WorldWideScience

Sample records for asymmetric salt ion

  1. Intrinsic potential of cell membranes: opposite effects of lipid transmembrane asymmetry and asymmetric salt ion distribution

    DEFF Research Database (Denmark)

    Gurtovenko, Andrey A; Vattulainen, Ilpo

    2009-01-01

    Using atomic-scale molecular dynamics simulations, we consider the intrinsic cell membrane potential that is found to originate from a subtle interplay between lipid transmembrane asymmetry and the asymmetric distribution of monovalent salt ions on the two sides of the cell membrane. It turns out......Cl saline solution and the PE leaflet is exposed to KCl, the outcome is that the effects of asymmetric lipid and salt ion distributions essentially cancel one another almost completely. Overall, our study highlights the complex nature of the intrinsic potential of cell membranes under physiological...

  2. Salt supply to and significance of asymmetric salt diapirs

    DEFF Research Database (Denmark)

    Koyi, H.; Burliga, S.; Chemia, Zurab

    2012-01-01

    Salt diapirs can be asymmetric both internally and externally reflecting their evolution history. As such, this asymmetry bear a significant amount of information about the differential loading (± lateral forces) and in turn the salt supply that have shaped the diapir. In two dimensions...... southeastern overhang due to salt extrusion during Middle Cretaceous followed by its burial in Tertiary. This external asymmetry is also reflected in the internal configuration of the diapir which shows different rates of salt flow on the two halves of the structure. The asymmetric external and internal...

  3. Asymmetric Hydrogenation of 3-Substituted Pyridinium Salts.

    Science.gov (United States)

    Renom-Carrasco, Marc; Gajewski, Piotr; Pignataro, Luca; de Vries, Johannes G; Piarulli, Umberto; Gennari, Cesare; Lefort, Laurent

    2016-07-01

    The use of an equivalent amount of an organic base leads to high enantiomeric excess in the asymmetric hydrogenation of N-benzylated 3-substituted pyridinium salts into the corresponding piperidines. Indeed, in the presence of Et3 N, a Rh-JosiPhos catalyst reduced a range of pyridinium salts with ee values up to 90 %. The role of the base was elucidated with a mechanistic study involving the isolation of the various reaction intermediates and isotopic labeling experiments. Additionally, this study provided some evidence for an enantiodetermining step involving a dihydropyridine intermediate. PMID:27140832

  4. Room Temperature ionic liquids based on asymmetric ammonium salts

    OpenAIRE

    Shaheen, Sobia

    2013-01-01

    Ionic liquids, ILs, in principle, are salts composed of weakly coordinating ions which are liquids at low temperature (˂100 0C). Room temperature ionic liquids, RTILs are those salts which are liquid even at room temperature. Due to the unique properties, such as large liquid range, negligible vapour pressure, solubility of wide range of materials and potential to be recycled and reused, ILs have become a popular class of solvents and catalysts.This study reports the synthesis of a library of...

  5. Solitary waves in asymmetric electron-positron-ion plasmas

    Science.gov (United States)

    Lu, Ding; Li, Zi-Liang; Xie, Bai-Song

    2015-10-01

    > By solving the coupled equations of the electromagnetic field and electrostatic potential, we investigate solitary waves in an asymmetric electron-positron plasma and/or electron-positron-ion plasmas with delicate features. It is found that the solutions of the coupled equations can capture multipeak structures of solitary waves in the case of cold plasma, which are left out by using the long-wavelength approximation. By considering the effect of ion motion with respect to non-relativistic and ultra-relativistic temperature plasmas, we find that the ions' mobility can lead to larger-amplitude solitary waves; especially, this becomes more obvious for a high-temperature plasma. The effects of asymmetric temperature between electrons and positrons and the ion fraction on the solitary waves are also studied and presented. It is shown that the amplitudes of solitary waves decrease with positron temperature in asymmetric temperature electron-positron plasmas and decrease also with ion concentration.

  6. Elliptic and Triangular flow in asymmetric heavy-ion collisions

    CERN Document Server

    Haque, Md Rihan; Mohanty, Bedangadas

    2011-01-01

    We present a study of the elliptic (v2) and triangular (v3) flow and their corresponding eccentricity fluctuations for asymmetric (Au+Ag, Au+Cu and Au+Si) collisions at \\sqrt_NN = 200 GeV. These are compared to the corresponding results from symmetric (Au+Au and Cu+Cu) collisions at the same energy. The study which is carried out using a multi-phase transport (AMPT) model shows that triangularity (\\epsilon_3), fluctuations in triangularity and v3 do not show much variation for the different colliding ion sizes studied. However the eccentricity (\\epsilon_2), fluctuations in eccentricity and v2 shows a strong dependence on colliding ion size for a given number of participating nucleons. Our study thus indicates that asymmetric heavy-ion collisions could be used to constrain models dealing with flow fluctuations in heavy-ion collisions.

  7. Ion pumping in nanochannels using an asymmetric electrode array

    OpenAIRE

    Sparreboom, W.; Cucu, C.F.; Eijkel, J.C.T.; Berg, van den, T.J.T.P.; Locascio, L.E.; Gaitan, M.; Paegel, B.M.; Ross, D J; Vreeland, W. N.

    2008-01-01

    We demonstrate an ion pump, consisting of a nanochannel with an AC driven asymmetric electrode array. Our system enables us to actively pump ions using a low driving voltage. In all experiments the electrical double layers are overlapping. Via viscous coupling ion pumping is accompanied by liquid pumping. Actuation below 500 mV at 10 Hz results in a liquid velocity of ~10 μm/s, corresponding to an electrical ion current of ~400 fA. Finite element simulations support the experimental data.

  8. Multicomponent asymmetric reactions mediated by proline lithium salt

    DEFF Research Database (Denmark)

    Renzi, Polyssena; Overgaard, Jacob; Bella, Marco

    2010-01-01

    The multicomponent reaction between proline lithium salt, 2-cyclohexen-1-one and aliphatic aldehydes affords the 4- alkylidene-2-cyclohexen-1-ones, which are interesting fragrances, and bicyclic amino acids that bear four additional stereocenters, obtained as single stereoisomer....

  9. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jun-Ho; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng, E-mail: mcho@korea.ac.kr [Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 136-713 (Korea, Republic of); Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Heejae; Kim, Seongheun [Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of)

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O—D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O—D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O—D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O—D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O—D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O—D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O—D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O—D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O—D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O—D stretch mode is shown to be important and the asymmetric line shapes of the O—D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We

  10. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions.

    Science.gov (United States)

    Choi, Jun-Ho; Kim, Heejae; Kim, Seongheun; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O-D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O-D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O-D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O-D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O-D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O-D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O-D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O-D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O-D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O-D stretch mode is shown to be important and the asymmetric line shapes of the O-D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We anticipate that this

  11. Asymmetric ion transport through ion-channel-mimetic solid-state nanopores.

    Science.gov (United States)

    Guo, Wei; Tian, Ye; Jiang, Lei

    2013-12-17

    Both scientists and engineers are interested in the design and fabrication of synthetic nanofluidic architectures that mimic the gating functions of biological ion channels. The effort to build such structures requires interdisciplinary efforts at the intersection of chemistry, materials science, and nanotechnology. Biological ion channels and synthetic nanofluidic devices have some structural and chemical similarities, and therefore, they share some common features in regulating the traverse ionic flow. In the past decade, researchers have identified two asymmetric ion transport phenomena in synthetic nanofluidic structures, the rectified ionic current and the net diffusion current. The rectified ionic current is a diode-like current-voltage response that occurs when switching the voltage bias. This phenomenon indicates a preferential direction of transport in the nanofluidic system. The net diffusion current occurs as a direct product of charge selectivity and is generated from the asymmetric diffusion through charged nanofluidic channels. These new ion transport phenomena and the elaborate structures that occur in biology have inspired us to build functional nanofluidic devices for both fundamental research and practical applications. In this Account, we review our recent progress in the design and fabrication of biomimetic solid-state nanofluidic devices with asymmetric ion transport behavior. We demonstrate the origin of the rectified ionic current and the net diffusion current. We also identify several influential factors and discuss how to build these asymmetric features into nanofluidic systems by controlling (1) nanopore geometry, (2) surface charge distribution, (3) chemical composition, (4) channel wall wettability, (5) environmental pH, (6) electrolyte concentration gradient, and (7) ion mobility. In the case of the first four features, we build these asymmetric features directly into the nanofluidic structures. With the final three, we construct

  12. Receptacle model of salting-in by tetramethylammonium ions.

    Science.gov (United States)

    Hribar-Lee, Barbara; Dill, Ken A; Vlachy, Vojko

    2010-11-25

    Water is a poor solvent for nonpolar solutes. Water containing ions is an even poorer solvent. According to standard terminology, the tendency of salts to precipitate oils from water is called salting-out. However, interestingly, some salt ions, such as tetramethylammonium (TMA), cause instead the salting-in of hydrophobic solutes. Even more puzzling, there is a systematic dependence on solute size. TMA causes the salting-out of small hydrophobes and the salting-in of larger nonpolar solutes. We study these effects using NPT Monte Carlo simulations of the Mercedes-Benz (MB) + dipole model of water, which was previously shown to account for hydrophobic effects and ion solubilities in water. The present model gives a structural interpretation for the thermodynamics of salting-in. The TMA structure allows deep penetration by a first shell of waters, the dipoles of which interact electrostatically with the ion. This first water shell sets up a second water shell that is shaped to act as a receptacle that binds the nonpolar solute. In this way, a nonpolar solute can actually bind more tightly to the TMA ion than to another hydrophobe, leading to the increased solubility and salting-in. Such structuring may also explain why molecular ions do not follow the same charge density series as atomic ions do. PMID:21028768

  13. The Receptacle Model of Salting-In by Tetramethylammonium Ions

    Science.gov (United States)

    Hribar–Lee, Barbara; Dill, Ken A.; Vlachy, Vojko

    2010-01-01

    Water is a poor solvent for nonpolar solutes. Water containing ions is an even poorer solvent. According to standard terminology, the tendency of salts to precipitate oils from water is called salting-out. However, interestingly, some salt ions, such as tetramethylammonium (TMA), cause instead the salting-in of hydrophobic solutes. Even more puzzling, there is a systematic dependence on solute size. TMA causes the salting-out of small hydrophobes and the salting-in of larger nonpolar solutes. We study these effects using NPT Monte Carlo simulations of the MB + dipole model of water, which was previously shown to account for hydrophobic effects and ion solubilities in water. The present model gives a structural interpretation for the thermodynamics of salting-in. The TMA structure allows deep penetration by a first shell of waters, the dipoles of which interact electrostatically with the ion. This first water shell sets up a second water shell that is shaped to act as a receptacle that binds the nonpolar solute. In this way, a nonpolar solute can actually bind more tightly to the TMA ion than to another hydrophobe, leading to the increased solubility and salting-in. Such structuring may also explain why molecular ions do not follow the same charge density series’ as atomic ions do. PMID:21028768

  14. Field Asymmetric Waveform Ion Mobility Spectrometry Studies of Proteins: Dipole Alignment in Ion Mobility Spectrometry?

    Energy Technology Data Exchange (ETDEWEB)

    Shvartsburg, Alexandre A.; Bryskiewicz, Tadeusz; Purves, Randy; Tang, Keqi; Guevremont, Roger; Smith, Richard D.

    2006-11-02

    Approaches to characterization and separation of ions involving their mobilities in gases were developed since 1960-s. Conventional ion mobility spectrometry (IMS) measures the absolute mobility and the field asymmetric waveform IMS (FAIMS) exploits the difference between mobilities at high and low electric fields. However, all previous work was based on the orientationally averaged cross-sections Ωavg between ions and buffer gas molecules. Virtually all large ions are electric dipoles that will be oriented by a sufficiently strong electric field. At typical FAIMS conditions, that must happen for dipole moments > ~400 Debye, found for many macroions including most proteins above ~30 kDa. Mobilities of aligned dipoles depend on directional cross-sections Ωdir (rather than Ωavg), which should have a major effect on FAIMS separation parameters. Here we study the FAIMS behavior of ESI-generated ions for ten proteins up to ~70 kDa. Those above 29 kDa exhibit a strong increase of mobility at high field, which is consistent with predicted ion dipole alignment. This effect expands the FAIMS peak capacity by an order of magnitude, allowing separation of up to ~102 distinct protein conformers and revealing information about Ωdir and ion dipole moment that is of potential utility for structural characterization. Possible means to extend the dipole alignment to smaller ions are discussed.

  15. Hypertension: Salt restriction, sodium homeostasis, and other ions

    OpenAIRE

    Neeru Gupta; Kishan Kumar Jani; Nivedita Gupta

    2011-01-01

    Salt is composed of Sodium Chloride (NaCl) which in body water becomes essential electrolytes, viz., Sodium (Na >+ ) and Chloride (Cl >- ) ions, including in the blood and other extracellular fluids (ECF). Na >+ ions are necessary cations in muscle contractions and their depletion will effect all the muscles in body including smooth muscle contraction of blood vessels, a fact which is utilized in lowering the blood pressure. Na+ ions also hold water with them in the ECF. Na >+ homeostasis in ...

  16. Ion flux profiles and plant ion homeostasis control under salt stress

    OpenAIRE

    Sun, Jian; Chen, Shao-Liang; Dai, Song-Xiang; Wang, Rui-gang; Li, Ni-Ya; Shen, Xin; Zhou, Xiao-Yang; Lu, Cun-Fu; Zheng, Xiao-Jiang; Hu, Zan-Min; Zhang, Zeng-Kai; Song, Jin; Xu, Yue

    2009-01-01

    The ability of a plant to maintain an ionic homeostasis is crucial in plant salt tolerance. Direct evidence based on data from the non-invasive measurement of ion fluxes would not only offer new insight about the function of the transporter but also provide a whole plant approach for dissecting salt adaptation mechanisms. Here, we review some reports using the ion-selective microelectrodes to characterize the net ion fluxes of tissues or cells.

  17. Mitochondrial membranes with mono- and divalent salt: changes induced by salt ions on structure and dynamics

    DEFF Research Database (Denmark)

    Pöyry, Sanja; Róg, Tomasz; Karttunen, Mikko;

    2009-01-01

    membrane electrostatic potential. The changes induced by salt are more prominent in dynamical properties related to ion binding and formation of ion-lipid complexes and lipid aggregates, as rotational diffusion of lipids is slowed down by ions, especially in the case of CaCl(2). In the same spirit, lateral...... diffusion of lipids is slowed down rather considerably for increasing concentration of CaCl(2). Both findings for dynamic properties can be traced to the binding of ions with lipid head groups and the related changes in interaction patterns in the headgroup region, where the binding of Na(+) and Ca(2+) ions...

  18. Isotope separation using high-field asymmetric waveform ion mobility spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, David A.; Purves, Randy W.; Guevremont, Roger E-mail: roger.guevremont@nrc.ca

    2000-08-01

    A new apparatus for gas-phase separation of stable elemental isotopes at atmospheric pressure is described. A gaseous mixture of chloride isotopes was generated using electrospray ionization and introduced into the analyzer region of a high-field asymmetric waveform ion mobility spectrometer (FAIMS). The ion current exiting the FAIMS was sampled into a quadrupole mass spectrometer for isotope identification.

  19. Hypertension: Salt restriction, sodium homeostasis, and other ions

    Directory of Open Access Journals (Sweden)

    Neeru Gupta

    2011-01-01

    Full Text Available Salt is composed of Sodium Chloride (NaCl which in body water becomes essential electrolytes, viz., Sodium (Na >+ and Chloride (Cl >- ions, including in the blood and other extracellular fluids (ECF. Na >+ ions are necessary cations in muscle contractions and their depletion will effect all the muscles in body including smooth muscle contraction of blood vessels, a fact which is utilized in lowering the blood pressure. Na+ ions also hold water with them in the ECF. Na >+ homeostasis in body is maintained by thirst (water intake, kidneys (urinary excretion and skin (sweating. In Na >+ withdrawal, body tries to maintain homeostasis as far as possible. However, in certain conditions (e.g., during exercise, intake of drugs and in disorders causing Syndrome of Inappropriate Anti Diuretic Hormone Secretion (SIADH, diuretics, diarrhea coupled with moderate or severe dietary salt restriction (anorexia nervosa, hyponatremia can get precipitated. Hyponatremia is one end point in the spectrum of disorders caused by severe Na >+ depletion whereas in moderate depletion it can cause hypohydration (or less total body water and lower urinary volume (U v . Moreover, salt sensitivity varies in various populations leading to different responses in relation to dietary Na >+ intake. Diabetes and Hypertension often co-exist but Na >+ withdrawal in salt sensitive subjects worsens diabetes though hypertension gets better and reverse occurs in salt loading. Therefore, Na >+ or salt restriction may be non-physiological. In hypertensive subjects other alternatives to Na >+ withdrawal could be Potassium (K >+ and Calcium (Ca >2+ supplementation. Further studies are required to monitor safety/side effects of salt restriction.

  20. Hypertension: salt restriction, sodium homeostasis, and other ions.

    Science.gov (United States)

    Gupta, Neeru; Jani, Kishan Kumar; Gupta, Nivedita

    2011-03-01

    Salt is composed of Sodium Chloride (NaCl) which in body water becomes essential electrolytes, viz., Sodium (Na⁺) and Chloride (Cl⁻) ions, including in the blood and other extracellular fluids (ECF). Na⁺ ions are necessary cations in muscle contractions and their depletion will effect all the muscles in body including smooth muscle contraction of blood vessels, a fact which is utilized in lowering the blood pressure. Na⁺ ions also hold water with them in the ECF. Na⁺ homeostasis in body is maintained by thirst (water intake), kidneys (urinary excretion) and skin (sweating). In Na⁺ withdrawal, body tries to maintain homeostasis as far as possible. However, in certain conditions (e.g., during exercise, intake of drugs and in disorders causing Syndrome of Inappropriate Anti Diuretic Hormone Secretion (SIADH), diuretics, diarrhea) coupled with moderate or severe dietary salt restriction (anorexia nervosa), hyponatremia can get precipitated. Hyponatremia is one end point in the spectrum of disorders caused by severe Na⁺ depletion whereas in moderate depletion it can cause hypohydration (or less total body water) and lower urinary volume (U v ). Moreover, salt sensitivity varies in various populations leading to different responses in relation to dietary Na⁺ intake. Diabetes and Hypertension often co-exist but Na⁺ withdrawal in salt sensitive subjects worsens diabetes though hypertension gets better and reverse occurs in salt loading. Therefore, Na⁺ or salt restriction may be non-physiological. In hypertensive subjects other alternatives to Na⁺ withdrawal could be Potassium (K⁺) and Calcium (Ca⁺²) supplementation. Further studies are required to monitor safety/side effects of salt restriction. PMID:23250294

  1. Ion track symmetric and asymmetric nanopores in polyethylene terephthalate foils for versatile applications

    Science.gov (United States)

    Apel, P. Yu.; Blonskaya, I. V.; Dmitriev, S. N.; Orelovich, O. L.; Sartowska, B. A.

    2015-12-01

    In this report we present several fabrication methods which allow production of ion track nanopore membranes with different pore configurations. Polymer foils, typically polyethylene terephthalate with a thickness of 5-23 μm, are irradiated with accelerated heavy ions (energy of 1-10 MeV/u) and then subjected to different physico-chemical treatments. Depending on the procedure, symmetric or asymmetric pores with nanoscale-sized narrowing are obtained. The asymmetric configurations include conical, funnel-like and bullet-like shapes. In electrolyte solutions the asymmetric nanopores exhibit diode-like properties which strongly depend on the pore shape. The peculiar features of such pores provide a basis for various applications.

  2. An inversion-asymmetric source function for HBT analysis in relativistic heavy ion collisions

    OpenAIRE

    Lianshou, Liu; Shusu, Shi; Jiaxin, Du

    2006-01-01

    The inversion-asymmetry of the emission source in relativistic heavy ion collision under the Bertsch-Pratt convention is discussed and explicitly exhibited by a Monte Carlo model. The Gaussian source function popularly used in the HBT analysis of relativistic heavy ion collisions is invalid in this case. An inversion-asymmetric source function is suggested. A method for extracting the inversion-asymmetry degree of the source together with the source size from experimental data is proposed.

  3. Ion yields for some salts in MALDI: mechanism for the gas-phase ion formation from preformed ions.

    Science.gov (United States)

    Moon, Jeong Hee; Shin, Young Sik; Bae, Yong Jin; Kim, Myung Soo

    2012-01-01

    Preformed ion emission is the main assumption in one of the prevailing theories for peptide and protein ion formation in matrix-assisted laser desorption ionization (MALDI). Since salts are in preformed ion forms in the matrix-analyte mixture, they are ideal systems to study the characteristics of preformed ion emission. In this work, a reliable method to measure the ion yield (IY) in MALDI was developed and used for a solid salt benzyltriphenylphosphonium chloride and two room-temperature ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate and trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate. IY for the matrix (α-cyano-4-hydroxycinnamic acid, CHCA) was also measured. Taking 1 pmol salts in 25 nmol CHCA as examples, IYs for three salts were similar, (4-8) × 10(-4), and those for CHCA were (0.8-1.2) × 10(-7). Even though IYs for the salts and CHCA remained virtually constant at low analyte concentration, they decreased as the salt concentrations increased. Two models, Model 1 and Model 2, were proposed to explain low IYs for the salts and the concentration dependences. Both models are based on the fact that the ion-pair formation equilibrium is highly shifted toward the neutral ion pair. In Model 1, the gas-phase analyte cations were proposed to originate from the same cations in the solid that were dielectrically screened from counter anions by matrix neutrals. In Model 2, preformed ions were assumed to be released from the solid sample in the form of neutral ion pairs and the anions in the ion pairs were assumed to be eliminated via reactions with matrix-derived cations.

  4. Electrodialysis-ion exchange for the separation of dissolved salts

    Energy Technology Data Exchange (ETDEWEB)

    Baroch, C.J. [Wastren, Inc., Westminster, CO (United States); Grant, P.J. [Wastren, Inc., Hummelstown, PA (United States)

    1995-10-01

    The Department of Energy generates and stores a significant quantity of low level, high level, and mixed wastes. As some of the DOE facilities are decontaminated and decommissioned, additional and possibly different forms of wastes will be generated. A significant portion of these wastes are aqueous streams containing acids, bases, and salts, or are wet solids containing inorganic salts. Some of these wastes are quite dilute solutions, whereas others contain large quantities of nitrates either in the form of dissolved salts or acids. Many of the wastes are also contaminated with heavy metals, radioactive products, or organics. Some of these wastes are in storage because a satisfactory treatment and disposal processes have not been developed. There is considerable interest in developing processes that remove or destroy the nitrate wastes. Electrodialysis-Ion Exchange (EDIX) is a possible process that should be more cost effective in treating aqueous waste steams. This report describes the EDIX process.

  5. Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination

    Science.gov (United States)

    Kwak, Rhokyun; Pham, Van Sang; Kim, Bumjoo; Chen, Lan; Han, Jongyoon

    2016-05-01

    Chloride ion, the majority salt in nature, is ∼52% faster than sodium ion (DNa+ = 1.33, DCl‑ = 2.03[10‑9m2s‑1]). Yet, current electrochemical desalination technologies (e.g. electrodialysis) rely on bipolar ion conduction, removing one pair of the cation and the anion simultaneously. Here, we demonstrate that novel ion concentration polarization desalination can enhance salt removal under a given current by implementing unipolar ion conduction: conducting only cations (or anions) with the unipolar ion exchange membrane stack. Combining theoretical analysis, experiment, and numerical modeling, we elucidate that this enhanced salt removal can shift current utilization (ratio between desalted ions and ions conducted through electrodes) and corresponding energy efficiency by the factor ∼(D‑ ‑ D+)/(D‑ + D+). Specifically for desalting NaCl, this enhancement of unipolar cation conduction saves power consumption by ∼50% in overlimiting regime, compared with conventional electrodialysis. Recognizing and utilizing differences between unipolar and bipolar ion conductions have significant implications not only on electromembrane desalination, but also energy harvesting applications (e.g. reverse electrodialysis).

  6. Structure, Ion Transport, and Rheology of Nanoparticle Salts

    KAUST Repository

    Wen, Yu Ho

    2014-07-08

    Above a critical surface chemistry-dependent particle loading associated with nanoscale interparticle spacing, ligand-ligand interactions-both electrostatic and steric-come into play and govern the structure and dynamics of charged oligomer-functionalized nanoparticle suspensions. We report in particular on the structure, ion transport, and rheology of suspensions of nanoparticle salts created by cofunctionalization of silica particles with tethered sulfonate salts and oligomers. Dispersion of the hairy ionic particles into medium and high dielectric constant liquids yields electrolytes with unique structure and transport properties. We find that electrostatic repulsion imparted by ion dissociation can be tuned to control the dispersion state and rheology through counterion size (i.e., Li+, Na+, and K+) and dielectric properties of the dispersing medium. Analysis of small-angle X-ray scattering (SAXS) structure factors and the mechanical modulus shows that when the interparticle spacing approaches nanometer dimensions, weakly entangled anchored ligands experience strong and long-lived topological constraints analogous to those normally found in well-entangled polymeric fluids. This finding provides insight into the molecular origins of the surprisingly similar rubbery plateau moduli observed in hairy nanoparticle suspensions and entangled polymers of the same chemistry as the tethered ligands. Additionally, we find that a time-composition superposition (TCS) principle exists for the suspensions, which can be used to substantially extend the observation time over which dynamics are observed in jammed, soft glassy suspensions. Application of TCS reveals dynamical similarities between the suspensions and entangled solutions of linear polymer chains; i.e., a hairy particle trapped in a cage appears to exhibit analogous dynamics to a long polymer chain confined to a tube. © 2014 American Chemical Society.

  7. Ion aggregation in high salt solutions. V. Graph entropy analyses of ion aggregate structure and water hydrogen bonding network

    Science.gov (United States)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-05-01

    Dissolved ions in water tend to form polydisperse ion aggregates such as ion pairs, relatively compact ion clusters, and even spatially extended ion networks with increasing salt concentration. Combining molecular dynamics simulation and graph theoretical analysis methods, we recently studied morphological structures of ion aggregates with distinctively different characteristics. They can be distinguished from each other by calculating various spectral graph theoretical properties such as eigenvalues and eigenvectors of adjacency matrices of ion aggregates and water hydrogen-bonding networks, minimum path lengths, clustering coefficients, and degree distributions. Here, we focus on percolation and graph entropic properties of ion aggregates and water hydrogen-bonding networks in high salt solutions. Ion network-forming K+ and SCN- ions at high concentrations show a percolating behavior in their aqueous solutions, but ion cluster-forming ions in NaCl solutions do not show such a transition from isolated ion aggregates to percolating ion-water mixture morphology. Despite that the ion aggregate structures are strikingly different for either cluster- or network-forming ions in high salt solutions, it is interesting that the water structures remain insensitive to the electrostatic properties, such as charge densities and polydentate properties, of dissolved ions, and morphological structures of water H-bonding networks appear to be highly robust regardless of the nature and concentration of salt. We anticipate that the present graph entropy analysis results would be of use in understanding a variety of anomalous behaviors of interfacial water around biomolecules as well as electric conductivities of high electrolyte solutions.

  8. Crystalline Silicotitanate Ion Exchange Support for Salt-Alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.F.

    2001-02-23

    The current version of crystalline silicotitanate (TAM5) is commercially available from UOP under the trade name IONSIV IE-911. TAM5 was extensively tested by several researchers and was determined as the best currently available material for removing radioisotopes from various types of nuclear wastes salt solutions stored at various DOE sites. The studies at Savannah River Technology Center (SRTC) indicated that the CST granules tend to leach into the nuclear waste simulants as it is processed by the ion exchange columns that is packed with CST granules from UOP. We, at Texas A and M University, agreed to conduct research to compliment the efforts at SRTC so that IONSIV IE-911 could be used for the treatment of nuclear waste stored at the DOE Savannah River facility. After consultation, we developed a Task Plan in January 2000. According to the agreement between Westinghouse Savannah River Company, Savannah River Technology Center, Aiken SC 29808 and, College Station, TX 77843, synthesis and the performance evaluations of crystalline silicotitanates (CST) were performed the during period of April 1 - September 30, 2000. Our main goals were delivery of a kilogram of CST (TAM5-4) synthesized at Texas A and M University in July to SRTC, performance evaluation of CST in nuclear waste simulants, and consultation mainly by telephone.

  9. Separation and identification of isomeric glycopeptides by high field asymmetric waveform ion mobility spectrometry.

    Science.gov (United States)

    Creese, Andrew J; Cooper, Helen J

    2012-03-01

    The analysis of intact glycopeptides by mass spectrometry is challenging due to the numerous possibilities for isomerization, both within the attached glycan and the location of the modification on the peptide backbone. Here, we demonstrate that high field asymmetric wave ion mobility spectrometry (FAIMS), also known as differential ion mobility, is able to separate isomeric O-linked glycopeptides that have identical sequences but differing sites of glycosylation. Two glycopeptides from the glycoprotein mucin 5AC, GT(GalNAc)TPSPVPTTSTTSAP and GTTPSPVPTTST(GalNAc)TSAP (where GalNAc is O-linked N-acetylgalactosamine), were shown to coelute following reversed-phase liquid chromatography. However, FAIMS analysis of the glycopeptides revealed that the compensation voltage ranges in which the peptides were transmitted differed. Thus, it is possible at certain compensation voltages to completely separate the glycopeptides. Separation of the glycopeptides was confirmed by unique reporter ions produced by supplemental activation electron transfer dissociation mass spectrometry. These fragments also enable localization of the site of glycosylation. The results suggest that glycan position plays a key role in determining gas-phase glycopeptide structure and have implications for the application of FAIMS in glycoproteomics.

  10. Secondary emission of negative ions and electrons resulting from electronic sputtering of cesium salts

    International Nuclear Information System (INIS)

    Secondary ion emission of negative ions and electrons from alkali salts bombarded with high energy (9 MeV) Ar+++ is discussed. Quite different features are observed according to the nature of the salt investigated (halide or oxygenated). In the case of cesium, the electron emission from halides is characterized by intense electron showers (several hundred electrons) with narrow distributions in intensity and orientation. Conversely, for oxygenated salts, these distributions are broader, much less intense (one order of magnitude), and the ion emission exhibits an dissymmetry, which has never been observed for inorganics. This last result is interpreted in terms of radiolysis of the oxygenated salt, a process well documented for gamma-ray irradiation, but not yet reported in secondary ion emission. (author) 17 refs.; 10 figs

  11. Asymmetric Aldol Reaction Catalyzed by L-Proline and Achiral Thiourea Fluoroboric Acid Salt

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Eun; Lee, Haney; Kim, Taek Hyeon [Chonnam National University, Gwangju (Korea, Republic of)

    2015-01-15

    Considering its ready availability and low cost, L-proline would be the first choice catalyst for preparing aldol adducts with high diastereo- and enantioselectivity. However, proline presents some major drawbacks, including poor performance in direct aldol reactions with aromatic aldehydes, limited solubility, and reactivity in nonpolar organic solvents, and side reactions that make using high catalyst loadings necessary to reach satisfactory conversions. Therefore, numerous proline-modified organo catalysts such as prolinamides, proline thioamides, sulfonamides, chiral amines, and organic salts have been designed for direct aldol reactions. An alternative is to add a readily available additive to the reactions containing proline. This last approach is clearly advantageous in avoiding tedious chemical syntheses of organo catalysts and would ultimately allow the construction of libraries of catalyst protocols by simply changing the additive. Acid additives can influence the outcome of enamine mediated reactions; however, only a few screening studies of acid additions to thiourea organo catalysts are available in the literature. The reaction between cyclohexanone and 4-nitrobenzaldehyde was selected as a standard model reaction for screening of more effective acid additives to thiourea.

  12. Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids

    Directory of Open Access Journals (Sweden)

    Carmen Nájera

    2004-04-01

    Full Text Available Alkaloids such as cinchonidine, quinine and N-methylephedrine have been N-alkylated using polymeric benzyl halides or co-polymerized and then N-alkylated, thus affording a series of polymer-supported chiral ammonium salts which have been employed as phase-transfer catalysts in the asymmetric benzylation of an N-(diphenylmethyleneglycine ester. These new polymeric catalysts can be easily recovered by simple filtration after the reaction and reused. The best ee’s were achieved when Merrifield resin-anchored cinchonidinium ammonium salts were employed.

  13. Systematization of the mass spectra for speciation of inorganic salts with static secondary ion mass spectrometry.

    Science.gov (United States)

    Van Ham, Rita; Van Vaeck, Luc; Adams, Freddy C; Adriaens, Annemie

    2004-05-01

    The analytical use of mass spectra from static secondary ion mass spectrometry for the molecular identification of inorganic analytes in real life surface layers and microobjects requires an empirical insight in the signals to be expected from a given compound. A comprehensive database comprising over 50 salts has been assembled to complement prior data on oxides. The present study allows the systematic trends in the relationship between the detected signals and molecular composition of the analyte to be delineated. The mass spectra provide diagnostic information by means of atomic ions, structural fragments, molecular ions, and adduct ions of the analyte neutrals. The prediction of mass spectra from a given analyte must account for the charge state of the ions in the salt, the formation of oxide-type neutrals from oxy salts, and the occurrence of oxidation-reduction processes.

  14. Asymmetric catalytic formation of quaternary carbons by iminium ion trapping of radicals

    Science.gov (United States)

    Murphy, John J.; Bastida, David; Paria, Suva; Fagnoni, Maurizio; Melchiorre, Paolo

    2016-04-01

    An important goal of modern organic chemistry is to develop new catalytic strategies for enantioselective carbon–carbon bond formation that can be used to generate quaternary stereogenic centres. Whereas considerable advances have been achieved by exploiting polar reactivity, radical transformations have been far less successful. This is despite the fact that open-shell intermediates are intrinsically primed for connecting structurally congested carbons, as their reactivity is only marginally affected by steric factors. Here we show how the combination of photoredox and asymmetric organic catalysis enables enantioselective radical conjugate additions to β,β-disubstituted cyclic enones to obtain quaternary carbon stereocentres with high fidelity. Critical to our success was the design of a chiral organic catalyst, containing a redox-active carbazole moiety, that drives the formation of iminium ions and the stereoselective trapping of photochemically generated carbon-centred radicals by means of an electron-relay mechanism. We demonstrate the generality of this organocatalytic radical-trapping strategy with two sets of open-shell intermediates, formed through unrelated light-triggered pathways from readily available substrates and photoredox catalysts—this method represents the application of iminium ion activation (a successful catalytic strategy for enantioselective polar chemistry) within the realm of radical reactivity.

  15. Scaling of triple differential cross-sections for asymmetric (, 2) process on helium isoelectronic ions by fast electrons

    Indian Academy of Sciences (India)

    M K Srivastava

    2005-01-01

    A simple scaling law is obtained for asymmetric (, 2) process on helium isoelectronic ions by fast electrons. It is based on treating the targets as having one active electron moving in the effective Coulomb field of the atomic core with an effective charge ' = − 5/8. This effective charge is also used in the description of the scattered and ejected electrons. The model has been tested against other available (, 2) results on helium in asymmetric geometry. The scaling law is found to work reasonably well for fast incident electrons and becomes increasingly accurate as target increases.

  16. Mathematical modeling of salt-gradient ion-exchange simulated moving bed chromatography for protein separations

    Institute of Scientific and Technical Information of China (English)

    卢建刚

    2004-01-01

    The salt-gradient operation mode used in ion-exchange simulated moving bed chromatography (SMBC) can improve the efficiency of protein separations. A detailed model that takes into account any kind of adsorption/ion-exchange equilibrium, salt gradient, size exclusion, mass transfer resistance, and port periodic switching mechanism, was developed to simulate the complex dynamics. The model predictions were verified by the experimental data on upward and downward gradients for protein separations reported in the literature. All design and operating parameters (number, configuration, length and diameter of columns, particle size, switching period, flow rates of feed, raffinate, desorbent and extract, protein concentrations in feed, different salt concentrations in desorbent and feed) can be chosen correctly by numerical simulation. This model can facilitate the design, operation, optimization, control and scale-up of salt-gradient ion-exchange SMBC for protein separations.

  17. Potassium Ions are More Effective than Sodium Ions in Salt Induced Peptide Formation

    Science.gov (United States)

    Dubina, Michael V.; Vyazmin, Sergey Yu.; Boitsov, Vitali M.; Nikolaev, Eugene N.; Popov, Igor A.; Kononikhin, Alexey S.; Eliseev, Igor E.; Natochin, Yuri V.

    2013-04-01

    Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K+ is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na+, which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K+ as the driving force, not Na+, as commonly believed.

  18. Potentiometric Sensor for Real-Time Monitoring of Multivalent Ion Concentrations in Molten Salt

    Energy Technology Data Exchange (ETDEWEB)

    Peter A. Zink; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson; Ben F. Cowan; Steven D. Herrmann; Shelly X. Li

    2010-07-01

    Electrorefining of spent metallic nuclear fuel in high temperature molten salt systems is a core technology in pyroprocessing, which in turn plays a critical role in the development of advanced fuel cycle technologies. In electrorefining, spent nuclear fuel is treated electrochemically in order to effect separations between uranium, noble metals, and active metals, which include the transuranics. The accumulation of active metals in a lithium chloride-potassium chloride (LiCl-KCl) eutectic molten salt electrolyte occurs at the expense of the UCl3-oxidant concentration in the electrolyte, which must be periodically replenished. Our interests lie with the accumulation of active metals in the molten salt electrolyte. The real-time monitoring of actinide concentrations in the molten salt electrolyte is highly desirable for controlling electrochemical operations and assuring materials control and accountancy. However, real-time monitoring is not possible with current methods for sampling and chemical analysis. A new solid-state electrochemical sensor is being developed for real-time monitoring of actinide ion concentrations in a molten salt electrorefiner. The ultimate function of the sensor is to monitor plutonium concentrations during electrorefining operations, but in this work gadolinium was employed as a surrogate material for plutonium. In a parametric study, polycrystalline sodium beta double-prime alumina (Na-ß?-alumina) discs and tubes were subject to vapor-phase exchange with gadolinium ions (Gd3+) using a gadolinium chloride salt (GdCl3) as a precursor to produce gadolinium beta double-prime alumina (Gd-ß?-alumina) samples. Electrochemical impedance spectroscopy and microstructural analysis were performed on the ion-exchanged discs to determine the relationship between ion exchange and Gd3+ ion conductivity. The ion-exchanged tubes were configured as potentiometric sensors in order to monitor real-time Gd3+ ion concentrations in mixtures of gadolinium

  19. Photocatalysis-triggered ion rectification in artificial nanochannels based on chemically modified asymmetric TiO2 nanotubes.

    Science.gov (United States)

    Hu, Ziying; Zhang, Qianqian; Gao, Jun; Liu, Zhaoyue; Zhai, Jin; Jiang, Lei

    2013-04-16

    Ion rectification is one of the important characteristics of biological ion channels. Inspired by the function of biological ion channels, creation of artificial nanochannels that show analogous ion rectification characteristics has attracted a great interest recently. Herein, we demonstrate a new type of artificial solid-state nanochannel with ion rectification characteristics. The creation of artificial nanochannels includes the formation of asymmetric TiO2 nanotubes by electrochemical anodization of Ti metal, followed by chemical modification with octadecyltrimethoxysilane (OTS) molecules. The carboxylic groups are introduced onto the tip side of TiO2 nanotubes via photocatalytic decomposition of OTS molecules by TiO2 photocatalysis under ultraviolet light. When the radius of tip side of TiO2 nanotubular channels is comparable to the thickness of electric double layer, the negatively charged surface in neutral electrolyte in combination with the asymmetric pore geometry contributes to the ion rectification characteristics. Compared with previous artificial nanochannels, our new type of artificial nanochannel is more facile to fabricate and behaves as a diode that rectifies the ion transport, which also shows some other potential applications, such as sensor and separation materials.

  20. Investigation of electron localization in harmonic emission from asymmetric molecular ion

    Institute of Scientific and Technical Information of China (English)

    张彩萍; 苗向阳

    2015-01-01

    We theoretically investigate the electron localization around two nuclei in harmonic emission from asymmetric molec-ular ion. The results show that the ionization process of electron localized around one nucleus competes with its transfer process to the other nucleus. By increasing the initial vibrational level, more electrons localized around the nucleus D+tend to transfer to the nucleus He2+so that the ionizations of electrons localized around the nucleus He2+increase. In this case, the difference in harmonic efficiency between HeH2+and HeD2+decreases while the difference in harmonic spectral structure increases. The evident minimum can be observed in the harmonic spectrum of HeH2+ compared with that in the spectral structure of HeD2+, which is due to the strong interference of multiple recombination channels originating from two nuclei. Time-dependent nuclear probability density, electron-nuclear probability density, double-well model, and time-frequency maps are presented to explain the underlying mechanisms.

  1. Detection of Potato Storage Disease via Gas Analysis: A Pilot Study Using Field Asymmetric Ion Mobility Spectrometry

    OpenAIRE

    Massimo Rutolo; Covington, James A.; John Clarkson; Daciana Iliescu

    2014-01-01

    Soft rot is a commonly occurring potato tuber disease that each year causes substantial losses to the food industry. Here, we explore the possibility of early detection of the disease via gas/vapor analysis, in a laboratory environment, using a recent technology known as FAIMS (Field Asymmetric Ion Mobility Spectrometry). In this work, tubers were inoculated with a bacterium causing the infection, Pectobacterium carotovorum, and stored within set environmental conditions in order to manage di...

  2. Regulation of ion homeostasis by aminolevulinic acid in salt-stressed wheat seedlings

    Science.gov (United States)

    Türk, Hülya; Genişel, Mucip; Erdal, Serkan

    2016-04-01

    Salinity is regarded as a worldwide agricultural threat, as it seriously limits plant development and productivity. Salt stress reduces water uptake in plants by disrupting the osmotic balance of soil solution. In addition, it creates a damaged metabolic process by causing ion imbalance in cells. In this study, we aim to examine the negative effects of 5-aminolevulinic acid (ALA) (20 mg/l) on the ion balance in wheat seedling leaves exposed to salt stress (150 mM). Sodium is known to be highly toxic for plant cells at high concentrations, and is significantly increased by salt stress. However, it can be reduced by combined application of ALA and salt, compared to salt application alone. On the other hand, while the K+/Na+ ratio was reduced by salt stress, ALA application changed this ratio in favor of K+. Manganese, iron, and copper were also able to reduce stress. However, ALA pre-treatment resulted in mineral level increments. Conversely, the stress-induced rise in magnesium, potassium, calcium, phosphorus, zinc, and molybdenum were further improved by ALA application. These data clearly show that ALA has an important regulatory effect of ion balance in wheat leaves.

  3. Transport of ions and biomolecules through single asymmetric nanopores in polymer films

    Science.gov (United States)

    Schiedt, Birgitta; Healy, Ken; Morrison, Alan P.; Neumann, Reinhard; Siwy, Zuzanna

    2005-07-01

    Single conical nanopores in polymer foils show 'rectifying' diode-like current-voltage (I-V) characteristics, with preferential cation flow in the direction from the narrow to the wide opening [P. Apel, Y.E. Korchev, Z. Siwy, R. Spohr, M. Yoshida, Nucl. Instr. and Meth. B 184 (2001) 337-346, Z. Siwy, D. Dobrev, R. Neumann, C. Trautmann, K. Voss, Appl. Phys. A 76 (2003) 781-785]. To produce single-pore membranes, we irradiated polymer films (polyethylene terephthalate and polyimide) with single heavy ions (using kinetic energies in the GeV range) and subsequently performed asymmetric chemical track-etching. The resulting conical pores had narrow openings of 4-20 nm. The I-V curves of these pores were measured in aqueous KCl solutions of various concentrations and pH values, and it was found that both parameters influence the rectification properties of the pores. For decreasing concentrations, down to 0.1 M, the degree of rectification increases, as predicted by a recently proposed model [Z. Siwy, A. Fulinski, Phys. Rev. Lett. 89 (2002) 198103], however, as the concentration decreases further, the rectification unexpectedly begins to decrease again. We suspect that this is due to conformation changes occurring in the pore. Also, our results have shown that the pores exhibit a non-classical conductance versus electrolyte concentration characteristic, having elevated conductances at low concentrations, for which we propose an explanation based on surface conductivity. Finally, we present an application of the polyimide conical nanopores as single-molecule DNA sensors, with results demonstrating their ability to detect individual plasmid DNA molecules.

  4. Electrokinetic salt removal from porous building materials using ion exchange membranes

    NARCIS (Netherlands)

    Kamran, K.; Van Soestbergen, M.; Pel, L.

    The removal of salt from porous building materials under the influence of an applied voltage gradient normally results in high pH gradients due to the formation of protons and hydroxyl ions at the electrodes. The formed acidic and alkaline regions not only lead to disintegration of the porous materi

  5. Potentiometric Sensor for Real-Time Monitoring of Multivalent Ion Concentrations in Molten Salt

    International Nuclear Information System (INIS)

    Electrorefining of spent metallic nuclear fuel in high temperature molten salt systems is a core technology in pyroprocessing, which in turn plays a critical role in the development of advanced fuel cycle technologies. In electrorefining, spent nuclear fuel is treated electrochemically in order to effect separations between uranium, noble metals, and active metals, which include the transuranics. The accumulation of active metals in a lithium chloride-potassium chloride (LiCl-KCl) eutectic molten salt electrolyte occurs at the expense of the UCl3-oxidant concentration in the electrolyte, which must be periodically replenished. Our interests lie with the accumulation of active metals in the molten salt electrolyte. The real-time monitoring of actinide concentrations in the molten salt electrolyte is highly desirable for controlling electrochemical operations and assuring materials control and accountancy. However, real-time monitoring is not possible with current methods for sampling and chemical analysis. A new solid-state electrochemical sensor is being developed for real-time monitoring of actinide ion concentrations in a molten salt electrorefiner. The ultimate function of the sensor is to monitor plutonium concentrations during electrorefining operations, but in this work gadolinium was employed as a surrogate material for plutonium. In a parametric study, polycrystalline sodium beta double-prime alumina (Na-β(doubleprime)-alumina) discs and tubes were subject to vapor-phase exchange with gadolinium ions (Gd3+) using a gadolinium chloride salt (GdCl3) as a precursor to produce gadolinium beta double-prime alumina (Gd-β(doubleprime)-alumina) samples. Electrochemical impedance spectroscopy and microstructural analysis were performed on the ion-exchanged discs to determine the relationship between ion exchange and Gd3+ ion conductivity. The ion-exchanged tubes were configured as potentiometric sensors in order to monitor real-time Gd3+ ion concentrations in

  6. Seed Treatment with Auxins Modulates Growth and Ion Partitioning in Salt-stressed Wheat Plants

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Experiments were performed to determine whether seed priming with different concentrations (100, 150, and 200 mg/L) of auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), or their precursor tryptophane (Trp)) could alter salinity induced perturbances in salicylic acid and ion concentrations and, hence, growth in wheat (Triticum aestivum L.) cultivars, namely M.H.-97 (salt intolerant) and Inqlab-91 (salt tolerant). Primed and non-primed seeds were sown in Petri dishes in a growth room, as well as in a field treated with 15 dS/m NaCl salinity. All priming agents, except IBA, increased the final germination percentage in both cultivars. The seedlings of either cultivar raised from Trp-treated seeds had greater dry biomass when under salt stress. In field experiments, Trp priming was much more effective in mediating the increase in grain yield,irrespective of the cultivar, under salt stress. The alleviatory effect of Trp was found to be associated with reduced uptake of Na+ in the roots and subsequent translocation to the shoots, as well as increased partitioning of Ca2+ in the roots of salt-stressed wheat plants. Plants of both cultivars raised from Trp- and IAA-treated seeds accumulated free salicylic acid in their leaves when under salt stress. Overall, the Trp priming-induced improvement in germination and the subsequent growth of wheat plants could be related to ion homeostasis when under salt stress. The possible involvement of salicylic acid in the Trp priming-induced better growth under conditions of salt stress is discussed.

  7. Ion Dynamics Study of Potato Starch + Sodium Salts Electrolyte System

    Directory of Open Access Journals (Sweden)

    Tuhina Tiwari

    2013-01-01

    Full Text Available The effect of different anions, namely, SCN−, I−, and ClO4−, on the electrical properties of starch-based polymer electrolytes has been studied. Anion size and conductivity are having an inverse trend indicating systems to be predominantly anionic conductor. Impact of anion size and multiplet forming tendency is reflected in number of charge carriers and mobility, respectively. Ion dynamics study reveals the presence of different mechanisms in different frequency ranges. Interestingly, superlinear power law (SLPL is found to be present at <5 MHz frequency, which is further confirmed by dielectric data.

  8. Effect of Salt Stress on Transpiration and Ion Distribution in Seedlings of Four Tree Species

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Transpiration rate and ion distribution of pagoda tree, walnut, velvet ash and poplar seedlings treated by NaCl solution of 0, 50, 100, 200 mmol·L-1 were studied. The results showed that there were significant differences in the response to NaCl among the four tree species. Na+ exclusion capacity of pagoda tree was the largest among the four species. The Na+ exclusion capacity of velvet ash was less than that of pagoda tree. Salt excretion capacity of velvet ash was limited. Its salt-tolerance was bigge...

  9. LiGa(OTf)(sub 4) as an Electrolyte Salt for Li-Ion Cells

    Science.gov (United States)

    Reddy, V. Prakash; Prakash, G. K. Syria; Hu, Jinbo; Yan, Ping; Smart, Marshall; Bugga, ratnakumar; Chin, Keith; Surampudi, Subarao

    2008-01-01

    Lithium tetrakis(trifluoromethane sulfo - nato)gallate [abbreviated "LiGa(OTf)4" (wherein "OTf" signifies trifluoro - methanesulfonate)] has been found to be promising as an electrolyte salt for incorporation into both liquid and polymer electrolytes in both rechargeable and non-rechargeable lithium-ion electrochemical cells. This and other ingredients have been investigated in continuing research oriented toward im proving the performances of rechargeable lithium-ion electrochemical cells, especially at low temperatures. This research at earlier stages, and the underlying physical and chemical principles, were reported in numerous previous NASA Tech Briefs articles. As described in more detail in those articles, lithiumion cells most commonly contain nonaqueous electrolyte solutions consisting of lithium hexafluorophosphate (LiPF6) dissolved in mixtures of cyclic and linear alkyl carbonates, including ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC). Although such LiPF6-based electrolyte solutions are generally highly ionically conductive and electrochemically stable, as needed for good cell performance, there is interest in identifying alternate lithium electrolyte salts that, relative to LiPF6, are more resilient at high temperature and are less expensive. Experiments have been performed on LiGa(OTf)4 as well as on several other candidate lithium salts in pursuit of this interest. As part of these experiments, LiGa(OTf)4 was synthesized by the reaction of Ga(OTf)3 with an equimolar portion of LiOTf in a solvent consisting of anhydrous acetonitrile. Evaporation of the solvent yielded LiGa(OTf)4 as a colorless crystalline solid. The LiGa(OTf)4 and the other salts were incorporated into solutions with PC and DMC. The resulting electrolyte solutions exhibited reasonably high ionic conductivities over a relatively wide temperature range down to 40 C (see figure). In cyclic

  10. Scaling of cross-sections for asymmetric (, 3) process on helium-like ions by fast electrons

    Indian Academy of Sciences (India)

    M K Srivastava

    2004-11-01

    An approximate simple scaling law is obtained for asymmetric (, 3) process on helium-like ions for double ionization by fast electrons. It is based on the equation $(Z'^{3} /)$ exp$[−Z' (r_{1} + r_{2})]$, $Z' = Z − (5/16)$ for ground state wave function of helium- like ions and $Z'^{2}$ scaling of energies. The scaling law is found to work very well if the lower energy electron is ejected along the momentum transfer direction and the other one is ejected in the opposite direction. It also works quite well if this electron is ejected within about 90° of the momentum transfer direction with the other electron going in the opposite direction. The scaling law becomes increasingly accurate as the target nuclear charge and the energy increase.

  11. Comparative Salt Stress Study on Intracellular Ion Concentration in Marine and Salt-adapted Freshwater Strains of Microalgae

    Directory of Open Access Journals (Sweden)

    Ahmad Farhad TALEBI

    2013-08-01

    Full Text Available Salinity imposes significant stresses in various living organisms including microalgae. High extracellular concentration of Na+ directly influences ionic balance inside the cell and subsequently the cellular activities. In the present study, the effect of such stress on growth and intracellular ions concentration (IIC of Dunaliella salina and Chlorella Spp. was investigated. IIC was analyzed using Ion chromatography technique. D. salina showed the highest degree of resistance to increase in salinity as little changes occurred both in IIC and in growth parameters. D. salina could maintain the balance of K+ inside the cell and eject the excess Na+ even at NaCl concentrations above 1M. Moreover, D. salina accumulated β-carotene in order to protect its photosynthetic apparatus. Among Chlorella species, C. vulgaris showed signs of adaptation to high content of salinity, though it is a fresh water species by nature. Moreover, the response shown by C. vulgaris to rise in salinity was even stronger than that of C. salina, which is presumably a salt-water resistant species. In fact, C. vulgaris could maintain intracellular K+ better than C. salina in response to increasing salinity, and as a result, it could survive at NaCl concentrations as high as 0.75 M. Marine strains such as D. salina well cope with the fluctuations in salinity through the existing adaptation mechanisms i.e. maintaining the K+/N+ balance inside the cell, K+ accumulation and Na+ ejection, accumulation of photosynthetic pigments like β-carotene.

  12. Enhancement of mass spectrometry performance for proteomic analyses using high-field asymmetric waveform ion mobility spectrometry (FAIMS).

    Science.gov (United States)

    Bonneil, Eric; Pfammatter, Sibylle; Thibault, Pierre

    2015-11-01

    Remarkable advances in mass spectrometry sensitivity and resolution have been accomplished over the past two decades to enhance the depth and coverage of proteome analyses. As these technological developments expanded the detection capability of mass spectrometers, they also revealed an increasing complexity of low abundance peptides, solvent clusters and sample contaminants that can confound protein identification. Separation techniques that are complementary and can be used in combination with liquid chromatography are often sought to improve mass spectrometry sensitivity for proteomics applications. In this context, high-field asymmetric waveform ion mobility spectrometry (FAIMS), a form of ion mobility that exploits ion separation at low and high electric fields, has shown significant advantages by focusing and separating multiply charged peptide ions from singly charged interferences. This paper examines the analytical benefits of FAIMS in proteomics to separate co-eluting peptide isomers and to enhance peptide detection and quantitative measurements of protein digests via native peptides (label-free) or isotopically labeled peptides from metabolic labeling or chemical tagging experiments. PMID:26505763

  13. Decreased Gap Width in a Cylindrical High-Field Asymmetric Waveform Ion Mobility Spectrometry Device Improves Protein Discovery.

    Science.gov (United States)

    Swearingen, Kristian E; Winget, Jason M; Hoopmann, Michael R; Kusebauch, Ulrike; Moritz, Robert L

    2015-12-15

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) is an atmospheric pressure ion mobility technique that separates gas phase ions according to their characteristic dependence of ion mobility on electric field strength. FAIMS can be implemented as a means of automated gas-phase fractionation in liquid chromatography-tandem mass spectrometry (LC-MS/MS) experiments. We modified a commercially available cylindrical FAIMS device by enlarging the inner electrode, thereby narrowing the gap and increasing the effective field strength. This modification provided a nearly 4-fold increase in FAIMS peak capacity over the optimally configured unmodified device. We employed the modified FAIMS device for on-line fractionation in a proteomic analysis of a complex sample and observed major increases in protein discovery. NanoLC-FAIMS-MS/MS of an unfractionated yeast tryptic digest using the modified FAIMS device identified 53% more proteins than were identified using an unmodified FAIMS device and 98% more proteins than were identified with unaided nanoLC-MS/MS. We describe here the development of a nanoLC-FAIMS-MS/MS protocol that provides automated gas-phase fractionation for proteomic analysis of complex protein digests. We compare this protocol against prefractionation of peptides with isoelectric focusing and demonstrate that FAIMS fractionation yields comparable protein recovery while significantly reducing the amount of sample required and eliminating the need for additional sample handling. PMID:26560994

  14. Ion motion in salt water flowing under a transverse magnetic field

    Directory of Open Access Journals (Sweden)

    De Luca R.

    2012-10-01

    Full Text Available The problem of ion motion in an electrolyte solution flowing in a thin rectangular duct with velocity VE in the presence of a transverse magnetic field B0 is studied by means of classical mechanics and electrodynamics. Because of Lorentz force on the ions in the electrolyte solution, a so called Faraday voltage appears at the electrodes orthogonal to both the field B0 and the velocity VE. The dynamics of positive and negative ions (cations and anions, respectively in this classical system is studied by taking into account the viscosity of the fluid and the process of charge accumulation on the opposite walls of the duct. Hydrogen production is seen to take place at one of the electrodes when salt water is taken as the flowing electrolyte.

  15. Lithium salt of tetrahydroxybenzoquinone: toward the development of a sustainable Li-ion battery.

    Science.gov (United States)

    Chen, Haiyan; Armand, Michel; Courty, Matthieu; Jiang, Meng; Grey, Clare P; Dolhem, Franck; Tarascon, Jean-Marie; Poizot, Philippe

    2009-07-01

    The use of lithiated redox organic molecules containing electrochemically active C=O functionalities, such as lithiated oxocarbon salts, is proposed. These represent alternative electrode materials to those used in current Li-ion battery technology that can be synthesized from renewable starting materials. The key material is the tetralithium salt of tetrahydroxybenzoquinone (Li(4)C(6)O(6)), which can be both reduced to Li(2)C(6)O(6) and oxidized to Li(6)C(6)O(6). In addition to being directly synthesized from tetrahydroxybenzoquinone by neutralization at room temperature, we demonstrate that this salt can readily be formed by the thermal disproportionation of Li(2)C(6)O(6) (dilithium rhodizonate phase) under an inert atmosphere. The Li(4)C(6)O(6) compound shows good electrochemical performance vs Li with a sustained reversibility of approximately 200 mAh g(-1) at an average potential of 1.8 V, allowing a Li-ion battery that cycles between Li(2)C(6)O(6) and Li(6)C(6)O(6) to be constructed. PMID:19476355

  16. Analysis of Supramolecular Complexes of 3-Methylxanthine with Field Asymmetric Waveform Ion Mobility Spectrometry Combined with Mass Spectrometry

    Science.gov (United States)

    Arthur, Kayleigh L.; Eiceman, Gary A.; Reynolds, James C.; Creaser, Colin S.

    2016-05-01

    Miniaturised field asymmetric waveform ion mobility spectrometry (FAIMS), combined with mass spectrometry (MS), has been applied to the study of self-assembling, noncovalent supramolecular complexes of 3-methylxanthine (3-MX) in the gas phase. 3-MX forms stable tetrameric complexes around an alkali metal (Na+, K+) or ammonium cation, to generate a diverse array of complexes with single and multiple charge states. Complexes of (3-MX)n observed include: singly charged complexes where n = 1-8 and 12 and doubly charged complexes where n = 12-24. The most intense ions are those associated with multiples of tetrameric units, where n = 4, 8, 12, 16, 20, 24. The effect of dispersion field on the ion intensities of the self-assembled complexes indicates some fragmentation of higher order complexes within the FAIMS electrodes (in-FAIMS dissociation), as well as in-source collision induced dissociation within the mass spectrometer. FAIMS-MS enables charge state separation of supramolecular complexes of 3-MX and is shown to be capable of separating species with overlapping mass-to-charge ratios. FAIMS selected transmission also results in an improvement in signal-to-noise ratio for low intensity complexes and enables the visualization of species undetectable without FAIMS.

  17. Changes in Transcript Related to Osmosis and Intracellular Ion Homeostasis in Paulownia tomentosa under Salt Stress.

    Science.gov (United States)

    Fan, Guoqiang; Wang, Limin; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng; Zhang, Xiaoshen; Li, Yongsheng

    2016-01-01

    Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including "plant hormone signal transduction," "RNA transporter," "protein processing in endoplasmic reticulum," and "plant-pathogen interaction," which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land.

  18. Changes in transcript related to osmosis and intracellular ion homeostasis in Paulownia tomentosa under salt stress

    Directory of Open Access Journals (Sweden)

    Guoqiang eFan

    2016-03-01

    Full Text Available Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including plant hormone signal transduction, RNA transporter, protein processing in endoplasmic reticulum and plant-pathogen interaction, which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land.

  19. Changes in Transcript Related to Osmosis and Intracellular Ion Homeostasis in Paulownia tomentosa under Salt Stress.

    Science.gov (United States)

    Fan, Guoqiang; Wang, Limin; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng; Zhang, Xiaoshen; Li, Yongsheng

    2016-01-01

    Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including "plant hormone signal transduction," "RNA transporter," "protein processing in endoplasmic reticulum," and "plant-pathogen interaction," which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land. PMID:27066034

  20. Effect of Surface and Salt Properties on the Ion Distribution around Spherical Nanoparticles: Monte Carlo Simulations.

    Science.gov (United States)

    Clavier, Arnaud; Carnal, Fabrice; Stoll, Serge

    2016-08-18

    Nanoparticle surface charge properties represent key parameters to predict their fate, reactivity, and complexation in natural, biological, and industrial dispersions. In this context, we present here an original approach to better understand the surface charge electrostatic properties of spherical nanoparticles (NPs). The ion distribution around one nanoparticle is investigated using Monte Carlo simulations and by adjusting a wide range of parameters including NP properties (surface charge density and site distribution), salt concentration (ionic strength and cation concentration), and salt valency (mono-, di-, and trivalent salt). A canonical Metropolis Monte Carlo method is used to reach equilibrium states and a primitive Coulomb model is applied to describe the electrostatic interactions between explicit discrete sites, counterions, and salt particles. Our results show that the presence of explicit surface charges on the NP and in solution has a strong influence on the local ion distribution and on the effective surface charge of the nanoparticles. The increase of surface charge density reduces the NP effective charge by the formation of a condensation layer around the nanoparticle. However, a limit of condensation is achieved due to steric effects and electrostatic repulsions. The presence of di- and trivalent cations is also found to strongly modify the effective charge and improve condensation state as long as electrostatic repulsion between the cations close to the surface are not so strong. At high trivalent cation concentration, the NP effective charge is greatly reduced and the local environment around the nanoparticle becomes more structured with the formation of a multi layer structure composed by anions and cations. PMID:27459187

  1. Pre-equilibrium dipole strength in charge asymmetric peripheral heavy-ion reactions

    International Nuclear Information System (INIS)

    We report on the results obtained from the study of the 32S+64Ni and 32S+58Ni peripheral reactions at incident energies Elab=288 MeV and Elab=320 MeV, respectively. High-energy γ-rays were detected in an array of 8 seven-pack BaF2 clusters. Coincidence with complex fragments detected in 12 three-stage telescopes ensured the selection of peripheral reaction events. All of the relevant reaction parameters were kept constant with the exception of the different initial dipole moment caused by the different entrance channel charge asymmetry. While for quasi-elastic events no N/Z effect was observed in the differential γ-ray multiplicities of the two reactions, for deep-inelastic events a larger dipole γ-ray emission occurs during the more N/Z asymmetric reaction. A theoretical interpretation based on a collective Bremsstrahlung analysis of the reaction dynamics is presented. (orig.)

  2. Influence of symmetry energy on the multifragmentation of asymmetric heavy-ion collisions

    International Nuclear Information System (INIS)

    In order to study the role of different density dependencies of symmetry energy on fragmentation pattern, we simulated thousands of events for the asymmetric collisions of 40Ar + 64Cu,108Ag, 197Au using soft equation of state supplemented by energy-dependent nucleon-nucleon cross-section reduced by 20%, i.e, σnn = 0.8 σfreenn free for three different values of γ= 0.5, 1 and 2. The choice of colliding geometry and incident energies is guided from the experimental measurements. As these reactions cover wide range of asymmetry (η = 0.2-0.6) and experimental measurements are also available, so we simulate these reactions to study the effect of different density dependencies of symmetry energy

  3. When do water-insoluble polyion-surfactant ion complex salts "redissolve" by added excess surfactant?

    Science.gov (United States)

    dos Santos, Salomé; Gustavsson, Charlotte; Gudmundsson, Christian; Linse, Per; Piculell, Lennart

    2011-01-18

    The redissolution of water-insoluble polyion-surfactant ion complexes by added excess of surfactant has systematically been investigated in experimental and theoretical phase equilibrium studies. A number of stoichiometric polyion-surfactant ion "complex salts" were synthesized and they consisted of akyltrimethylammonium surfactant ions of two different alkyl chain lengths (C(12)TA(+) and C(16)TA(+)) combined with homopolyions of polyacrylate of two different lengths (PA(-)(25) and PA(-)(6000)) or copolyions of acrylate and the slightly hydrophobic nonionic comonomers N-isopropylacrylamide (PA(-)-co-NIPAM) or N,N-dimethylacrylamide (PA(-)-co-DAM). The complex salts were mixed with water and excess alkyltrimethylammonium surfactant with either bromide or acetate counterions (C(n)TABr or C(n)TAAc). Factors promoting efficient redissolution were (i) very short polyions, (ii) a large fraction of NIPAM or DAM comonomers, and (iii) acetate, rather than bromide, as the surfactant counterion. Added C(12)TAAc gave an efficient redissolution of C(12)TAPA(25) but virtually no redissolution of C(12)TAPA(6000). A very efficient redissolution by added C(12)TAAc was obtained for PA(-)-co-NIPAM with 82 mol % of NIPAM. The C(12)TAPA-co-NIPAM/C(12)TAAc/H(2)O ternary phase diagram closely resembled the corresponding diagram for the much-studied pair cationic hydroxyethyl cellulose-(sodium) dodecyl sulfate. The simple Flory-Huggins theory adopted for polyelectrolyte systems successfully reproduced the main features of the experimental phase diagrams for the homopolyion systems, including the effect of the surfactant counterion. The efficient redissolution found for certain copolyion systems was explained by the formation of soluble polyion-surfactant ion complexes carrying an excess of surfactant ions through an additional hydrophobic attraction. PMID:21166446

  4. Nontarget analysis of urine by electrospray ionization-high field asymmetric waveform ion mobility-tandem mass spectrometry.

    Science.gov (United States)

    Beach, Daniel G; Gabryelski, Wojciech

    2011-12-01

    Nearly a decade after first commercialization, high field asymmetric waveform ion mobility spectrometry (FAIMS) has yet to find its place in routine chemical analysis. Prototypes have been used to demonstrate the utility of this separation technique combined with mass spectrometry (MS). Unfortunately, first generation commercial FAIMS instruments have gone practically unused by early adopters. Here, we show this to be due to poor ion transmission in the FAIMS-MS source interface. We present simple instrumental modifications and optimization of experimental conditions to achieve good performance from the first generation commercial FAIMS device (the Ionalytics Selectra) coupled to a high resolution Q-TOF-MS. In combination with nanospray ionization, we demonstrate for the first time the nontarget analysis of urine by FAIMS with minimal sample preparation. We show the unique suitability of electrospray ionization (ESI)-FAIMS-MS for identification of low abundance species such as urinary biomarkers of damage of nucleic acids in a complex biological matrix. The elimination of electrospray noise and matrix components by FAIMS and the continuous flow of analytes through FAIMS for accurate and tandem mass analysis produce high quality spectral data suitable for structural identification of unknowns. These characteristics make ESI-FAIMS-MS ideal for nontarget identification, even when compared to high efficiency LC-ESI-MS. PMID:21978137

  5. Interaction of the model alkyltrimethylammonium ions with alkali halide salts: an explicit water molecular dynamics study

    Directory of Open Access Journals (Sweden)

    M. Druchok

    2013-01-01

    Full Text Available We present an explicit water molecular dynamics simulation of dilute solutions of model alkyltrimethylammonium surfactant ions (number of methylene groups in the tail is 3, 5, 8, 10, and 12 in mixture with NaF, NaCl, NaBr, and NaI salts, respectively. The SPC/E model is used to describe water molecules. Results of the simulation at 298 K are presented in form of the radial distribution functions between nitrogen and carbon atoms of CH2 groups on the alkyltrimethylammonium ion, and the counterion species in the solution. The running coordination numbers between carbon atoms of surfactants and counterions are also calculated. We show that I- counterion exhibits the highest, and F- the lowest affinity to "bind" to the model surfactants. The results are discussed in view of the available experimental and simulation data for this and similar solutions.

  6. Characteristics and quantitative of negative ion in salt aqueous solution by Raman spectroscopy at -170℃

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Nai; ZHANG; Dajiang; ZHANG; Shuichang; ZHANG; Dijia

    2006-01-01

    The results from Raman spectroscopy analysis of salt aqueous solutions at -170℃ demonstrate that for those clearly sharp iron peaks whose Raman wavenumber is close to each other such as and , their original shape could be restorable by the stripping technique, and that ice's sharp characteristic peak (3090-3109 cm-1) is steady, while the spectrum band of the complex compound (nCl--[H+-OH-]n) chlorine ion combined chemically with water molecule is 3401-3413 cm-1. On the other hand, the research shows that the higher the negative iron concentration, the stronger its Raman characteristic peak intensity and the smaller the ice's. Based on the number of data and theoretical work, the strong correlation of the molar concentration of negative ion with the band area ratio is built up. Moreover, the developed Raman method is successfully used in the component analysis of the field fluid inclusions from Silurian sandstone in Tarim basin.

  7. Spin Frustration in an Organic Radical Ion Salt Based on a Kagome-Coupled Chain Structure.

    Science.gov (United States)

    Postulka, Lars; Winter, Stephen M; Mihailov, Adam G; Mailman, Aaron; Assoud, Abdeljalil; Robertson, Craig M; Wolf, Bernd; Lang, Michael; Oakley, Richard T

    2016-08-31

    Electro-oxidation of the quinoidal bisdithiazole BT in dichloroethane in the presence of [Bu4N][GaBr4] affords the 1:1 radical ion salt [BT][GaBr4], crystals of which belong to the trigonal space group P3. The packing pattern of the radical cations provides a rare example of an organic kagome basket structure, with S = 1/2 radical ion chains located at the triangular corners of a trihexagonal lattice. Magnetic measurements over a wide temperature range from 30 mK to 300 K suggest strongly frustrated AFM interactions on the scale of J/kb ∼ 30 K, but reveal no anomalies that would be associated with magnetic order. These observations are discussed in terms of the symmetry allowed magnetic interactions within and between the frustrated layers.

  8. A 2D ion chamber array audit of wedged and asymmetric fields in an inhomogeneous lung phantom

    International Nuclear Information System (INIS)

    Purpose: The Australian Clinical Dosimetry Service (ACDS) has implemented a new method of a nonreference condition Level II type dosimetric audit of radiotherapy services to increase measurement accuracy and patient safety within Australia. The aim of this work is to describe the methodology, tolerances, and outcomes from the new audit. Methods: The ACDS Level II audit measures the dose delivered in 2D planes using an ionization chamber based array positioned at multiple depths. Measurements are made in rectilinear homogeneous and inhomogeneous phantoms composed of slabs of solid water and lung. Computer generated computed tomography data sets of the rectilinear phantoms are supplied to the facility prior to audit for planning of a range of cases including reference fields, asymmetric fields, and wedged fields. The audit assesses 3D planning with 6 MV photons with a static (zero degree) gantry. Scoring is performed using local dose differences between the planned and measured dose within 80% of the field width. The overall audit result is determined by the maximum dose difference over all scoring points, cases, and planes. Pass (Optimal Level) is defined as maximum dose difference ≤3.3%, Pass (Action Level) is ≤5.0%, and Fail (Out of Tolerance) is >5.0%. Results: At close of 2013, the ACDS had performed 24 Level II audits. 63% of the audits passed, 33% failed, and the remaining audit was not assessable. Of the 15 audits that passed, 3 were at Pass (Action Level). The high fail rate is largely due to a systemic issue with modeling asymmetric 60° wedges which caused a delivered overdose of 5%–8%. Conclusions: The ACDS has implemented a nonreference condition Level II type audit, based on ion chamber 2D array measurements in an inhomogeneous slab phantom. The powerful diagnostic ability of this audit has allowed the ACDS to rigorously test the treatment planning systems implemented in Australian radiotherapy facilities. Recommendations from audits have led to

  9. Induction of salt tolerance in Azolla microphylla Kaulf through modulation of antioxidant enzymes and ion transport.

    Science.gov (United States)

    Abraham, Gerard; Dhar, Dolly Wattal

    2010-09-01

    Azolla microphylla plants exposed directly to NaCl (13 dsm(-1)) did not survive the salinity treatment beyond a period of one day, whereas plants exposed directly to 4 and 9 dsm(-1) NaCl were able to grow and produce biomass. However, plants pre-exposed to NaCl (2 dsm(-1)) for 7 days on subsequent exposure to 13 dsm(-1) NaCl were able to grow and produce biomass although at a slow rate and are hereinafter designated as pre-exposed plants. The pre-exposed and directly exposed plants distinctly differed in their response to salt in terms of lipid peroxidation, proline accumulation, activity of antioxidant enzymes, such as SOD, APX, and CAT, and Na(+)/K(+) ratio. Efficient modulation of antioxidant enzymes coupled with regulation of ion transport play an important role in the induction of salt tolerance. Results show that it is possible to induce salt adaptation in A. microphylla by pre-exposing them to low concentrations of NaCl. PMID:20422236

  10. Sorption of rare earth ions by alkylammonium salts of transition metal polyacids

    International Nuclear Information System (INIS)

    Consideration is given to results of investigations into gadolinium extraction from aqueous solutions by coprecipitation with hydrophobic compounds, formed during direct interaction of 12-tungstophosphoric acid (HPA) with surfactants (SA), depending on aqueous phase acidity, as well as SA nature and content. It was established that degree of gadolinium extraction increased with growth of pH value of the medium: gadolinium is concentrated in strong-acid media, as compared to yttrium. The process of gadolinium coprecipitation with HPA salts is also affected by the nature of precipitant: degree of metal extraction growth with increase of SA molecular mass. Gadolinium interaction with HPA salts takes place in result of ion exchange with salt-forming HPA protons. Data of IR spectroscopic investigations of the composition of hydrophobic precipitates, prepared under different conditions, are presented. Their content is not changed at different initial concentrations of HPA and gadolinium and depends only on pH of aqueous medium. Data of potentiometric titration of the compounds, supporting differences in interaction of gadolinium and yttrium with HPA, are presented

  11. Analysis of paralytic shellfish toxins using high-field asymmetric waveform ion mobility spectrometry with liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Beach, Daniel G; Melanson, Jeremy E; Purves, Randy W

    2015-03-01

    The analysis of paralytic shellfish toxins (PSTs) by liquid chromatography-mass spectrometry remains a challenge because of their high polarity, large number of analogues and the complex matrix in which they occur. Here we investigate the potential utility of high-field asymmetric waveform ion mobility spectrometry (FAIMS) as a gas-phase ion separation tool for analysis of PSTs by mass spectrometry. We investigate the separation of PSTs using FAIMS with two divergent goals: using FAIMS as a primary separation tool for rapid screening by electrospray ionization (ESI)-FAIMS-MS or combined with LC in a multidimensional LC-ESI-FAIMS-MS separation. First, a survey of the parameters that affect the sensitivity and selectivity of PST analysis by FAIMS was carried out using ESI-FAIMS-MS. In particular, the use of acetonitrile as a gas additive in the carrier gas flow offered good separation of all PST epimeric pairs. A second set of FAIMS conditions was also identified, which focussed PSTs to a relatively narrow CV range allowing development of an LC-ESI-FAIMS-MS method for analysis of PST toxins in complex mussel tissue extracts. The quantitative capabilities of this method were evaluated by analysing a PST containing mussel tissue matrix material. Results compared favourably with analysis by an established LC-post-column oxidation-fluorescence method with recoveries ranging from 70 to 106%, although sensitivity was somewhat reduced. The current work represents the first successful separation of PST isomers using ion mobility and shows the promise of FAIMS as a tool for analysis of algal biotoxins in complex samples and outlines some critical requirements for its future improvement.

  12. Multifragmentation in asymmetric heavy-ion collisions. An experimental trace search

    International Nuclear Information System (INIS)

    The author presents a review about experimental studies of multifragmentation in heavy ion collisions. After a description of the experimental methods for the study of such processes he describes the emission characteristics of medium heavy fragments like energy and angular distribution, production cross sections, and multiplicity. Then he considers statistical aspects of highly excited nuclei. Then the production of unstable fragments is discussed. Finally the author discusses the study of pp correlations looking for interference effects. (HSI)

  13. Charged patchy particle models in explicit salt: Ion distributions, electrostatic potentials, and effective interactions

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Cemil; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin (Germany); Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine,” 14513 Teltow (Germany); Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Heyda, Jan [Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Praha 6 (Czech Republic)

    2015-08-14

    We introduce a set of charged patchy particle models (CPPMs) in order to systematically study the influence of electrostatic charge patchiness and multipolarity on macromolecular interactions by means of implicit-solvent, explicit-ion Langevin dynamics simulations employing the Gromacs software. We consider well-defined zero-, one-, and two-patched spherical globules each of the same net charge and (nanometer) size which are composed of discrete atoms. The studied mono- and multipole moments of the CPPMs are comparable to those of globular proteins with similar size. We first characterize ion distributions and electrostatic potentials around a single CPPM. Although angle-resolved radial distribution functions reveal the expected local accumulation and depletion of counter- and co-ions around the patches, respectively, the orientation-averaged electrostatic potential shows only a small variation among the various CPPMs due to space charge cancellations. Furthermore, we study the orientation-averaged potential of mean force (PMF), the number of accumulated ions on the patches, as well as the CPPM orientations along the center-to-center distance of a pair of CPPMs. We compare the PMFs to the classical Derjaguin-Verwey-Landau-Overbeek theory and previously introduced orientation-averaged Debye-Hückel pair potentials including dipolar interactions. Our simulations confirm the adequacy of the theories in their respective regimes of validity, while low salt concentrations and large multipolar interactions remain a challenge for tractable theoretical descriptions.

  14. Primary amine/CSA ion pair: A powerful catalytic system for the asymmetric enamine catalysis

    KAUST Repository

    Liu, Chen

    2011-05-20

    A novel ion pair catalyst containing a chiral counteranion can be readily derived by simply mixing cinchona alkaloid-derived diamine with chiral camphorsulfonic acid (CSA). A mixture of 9-amino(9-deoxy)epi-quinine 8 and (-)-CSA was found to be the best catalyst with matching chirality, enabling the direct amination of α-branched aldehydes to proceed in quantitative yields and with nearly perfect enantioselectivities. A 0.5 mol % catalyst loading was sufficient to catalyze the reaction, and a gram scale enantioselective synthesis of biologically important α-methyl phenylglycine has been successfully demonstrated. © 2011 American Chemical Society.

  15. Influence of silicon on microdistribution of mineral ions in roots of salt-stressed barley as associated with salt tolerance in plants

    Institute of Scientific and Technical Information of China (English)

    梁永超; 丁瑞兴

    2002-01-01

    Two contrasting barley (Hordeum vulgare L.) cultivars: Kepin No.7 (salt sensitive), and Jian 4 (salt tolerant) were grown hydroponically to investigate the microdistribution of mineral ions in roots as affected by silicon (Si) with respect to salt tolerance. The experiment was undertaken consisting of two treatments with 3 replicates: (i) 120 mmol@L?1 NaCl alone (referred to as Si(NaCl+), (ii) 120 mmol@L?1 NaCl + 1.0 mmol@L?1 Si (as potassium silicate) (referred to as Si+NaCl+). Plant root tips were harvested for microanalysis using an energy dispersive X-ray microanalyzer (EDX) 30 d after transplanting. Higher Cl and Na X-ray peaks were recorded in the root epidermal, cortical and stelar cells of roots for the treatment Si(NaCl+ with the majorities of Na and Cl being accumulated in epidermal and cortical cells, while relatively low K peaks were observed regardless of the barley cultivars used. By contrast, considerably higher K peaks were detected in the epidermal, cortical and stelar cells of the roots for the treatment Si+NaCl+, but lower Cl and Na peaks were also observed for this treatment with both Na and Cl ions being evenly distributed in the epidermal, cortical and stelar cells. These findings directly support our previous finding, which showed that Si depressed the uptake of sodium but enhanced the uptake of potassium by salt-stressed barley. We believe that one of the possible mechanisms involved in Si-enhancement of salt tolerance in barley is attributed to the Si-induced changes in the uptake and microdistribution of mineral ions in plants.

  16. Detection of Potato Storage Disease via Gas Analysis: A Pilot Study Using Field Asymmetric Ion Mobility Spectrometry

    Directory of Open Access Journals (Sweden)

    Massimo Rutolo

    2014-08-01

    Full Text Available Soft rot is a commonly occurring potato tuber disease that each year causes substantial losses to the food industry. Here, we explore the possibility of early detection of the disease via gas/vapor analysis, in a laboratory environment, using a recent technology known as FAIMS (Field Asymmetric Ion Mobility Spectrometry. In this work, tubers were inoculated with a bacterium causing the infection, Pectobacterium carotovorum, and stored within set environmental conditions in order to manage disease progression. They were compared with controls stored in the same conditions. Three different inoculation time courses were employed in order to obtain diseased potatoes showing clear signs of advanced infection (for standard detection and diseased potatoes with no apparent evidence of infection (for early detection. A total of 156 samples were processed by PCA (Principal Component Analysis and k-means clustering. Results show a clear discrimination between controls and diseased potatoes for all experiments with no difference among observations from standard and early detection. Further analysis was carried out by means of a statistical model based on LDA (Linear Discriminant Analysis that showed a high classification accuracy of 92.1% on the test set, obtained via a LOOCV (leave-one out cross-validation.

  17. Detection of potato storage disease via gas analysis: a pilot study using field asymmetric ion mobility spectrometry.

    Science.gov (United States)

    Rutolo, Massimo; Covington, James A; Clarkson, John; Iliescu, Daciana

    2014-01-01

    Soft rot is a commonly occurring potato tuber disease that each year causes substantial losses to the food industry. Here, we explore the possibility of early detection of the disease via gas/vapor analysis, in a laboratory environment, using a recent technology known as FAIMS (Field Asymmetric Ion Mobility Spectrometry). In this work, tubers were inoculated with a bacterium causing the infection, Pectobacterium carotovorum, and stored within set environmental conditions in order to manage disease progression. They were compared with controls stored in the same conditions. Three different inoculation time courses were employed in order to obtain diseased potatoes showing clear signs of advanced infection (for standard detection) and diseased potatoes with no apparent evidence of infection (for early detection). A total of 156 samples were processed by PCA (Principal Component Analysis) and k-means clustering. Results show a clear discrimination between controls and diseased potatoes for all experiments with no difference among observations from standard and early detection. Further analysis was carried out by means of a statistical model based on LDA (Linear Discriminant Analysis) that showed a high classification accuracy of 92.1% on the test set, obtained via a LOOCV (leave-one out cross-validation). PMID:25171118

  18. Novel benzimidazole salts for lithium ion battery electrolytes: effects of substituents.

    Science.gov (United States)

    Sriana, T; Leggesse, E G; Jiang, J C

    2015-07-01

    In this paper, we report on our effort to design a novel lithium salt derived from bis(trifluoroborane)benzimidazolide by using density functional theory (DFT) calculations. The effects of different substituents are investigated with respect to ion pair dissociation energies and intrinsic anion oxidation potential of the molecules. Based on our calculations, we have found that ion pair dissociation energies and intrinsic anion oxidation potentials of the anions are mainly affected by the position and the type of substituents introduced into the parent structure. Compared to -CH3, substitution at the C2 position of the parent bis(trifluoroborane)benzimidazole (BTB(-)) by -CF3 results in an increase in anion oxidation stability. However, we observed a negligible change in the intrinsic anion oxidation potential as the length of the fluoroalkyl group increased to -C2F5. The most promising anions are generated by considering double-substitution at C2 and C5 positions. Among the possible anions, bis(trifluoroborane)-5-nitro-2-(trifluoromethyl) benzimidazolide (BTNTB(-)), with the calculated intrinsic anion oxidation potential of 5.50 V vs. Li(+)/Li, can be considered as a potential candidate for high voltage Li-ion batteries. PMID:26051990

  19. Membrane curvature generated by asymmetric depletion layers of ions, small molecules, and nanoparticles.

    Science.gov (United States)

    Różycki, Bartosz; Lipowsky, Reinhard

    2016-08-21

    Biomimetic and biological membranes consist of molecular bilayers with two leaflets that are typically exposed to different aqueous solutions. We consider solutions of "particles" that experience effectively repulsive interactions with these membranes and form depletion layers in front of the membrane leaflets. The particles considered here are water-soluble, have a size between a few angstrom and a few nanometers as well as a rigid, more or less globular shape, and do neither adsorb onto the membranes nor permeate these membranes. Examples are provided by ions, small sugar molecules, globular proteins, or inorganic nanoparticles with a hydrophilic surface. We first study depletion layers in a hard-core system based on ideal particle solutions as well as hard-wall interactions between these particles and the membrane. For this system, we obtain exact expressions for the coverages and tensions of the two leaflets as well as for the spontaneous curvature of the bilayer membrane. All of these quantities depend linearly on the particle concentrations. The exact results for the hard-core system also show that the spontaneous curvature can be directly deduced from the planar membrane geometry. Our results for the hard-core system apply both to ions and solutes that are small compared to the membrane thickness and to nanoparticles with a size that is comparable to the membrane thickness, provided the particle solutions are sufficiently dilute. We then corroborate the different relationships found for the hard-core system by extensive simulations of a soft-core particle system using dissipative particle dynamics. The simulations confirm the linear relationships obtained for the hard-core system. Both our analytical and our simulation results show that the spontaneous curvature induced by a single particle species can be quite large. When one leaflet of the membrane is exposed, e.g., to a 100 mM solution of glucose, a lipid bilayer can acquire a spontaneous curvature of ±1

  20. Membrane curvature generated by asymmetric depletion layers of ions, small molecules, and nanoparticles

    Science.gov (United States)

    RóŻycki, Bartosz; Lipowsky, Reinhard

    2016-08-01

    Biomimetic and biological membranes consist of molecular bilayers with two leaflets that are typically exposed to different aqueous solutions. We consider solutions of "particles" that experience effectively repulsive interactions with these membranes and form depletion layers in front of the membrane leaflets. The particles considered here are water-soluble, have a size between a few angstrom and a few nanometers as well as a rigid, more or less globular shape, and do neither adsorb onto the membranes nor permeate these membranes. Examples are provided by ions, small sugar molecules, globular proteins, or inorganic nanoparticles with a hydrophilic surface. We first study depletion layers in a hard-core system based on ideal particle solutions as well as hard-wall interactions between these particles and the membrane. For this system, we obtain exact expressions for the coverages and tensions of the two leaflets as well as for the spontaneous curvature of the bilayer membrane. All of these quantities depend linearly on the particle concentrations. The exact results for the hard-core system also show that the spontaneous curvature can be directly deduced from the planar membrane geometry. Our results for the hard-core system apply both to ions and solutes that are small compared to the membrane thickness and to nanoparticles with a size that is comparable to the membrane thickness, provided the particle solutions are sufficiently dilute. We then corroborate the different relationships found for the hard-core system by extensive simulations of a soft-core particle system using dissipative particle dynamics. The simulations confirm the linear relationships obtained for the hard-core system. Both our analytical and our simulation results show that the spontaneous curvature induced by a single particle species can be quite large. When one leaflet of the membrane is exposed, e.g., to a 100 mM solution of glucose, a lipid bilayer can acquire a spontaneous curvature of ±1

  1. Spatial Variability of Salt Ions in Soils in Oasis of Delta of Weigan River-Kuqa River in Different Seasons

    Institute of Scientific and Technical Information of China (English)

    Yuanyuan XU; Tashpolat TIYIP; Fei ZHANG; Jun XIA; Guihong HAN; Mamat SAWUT

    2012-01-01

    Abstract [Objective] The aim was to research the spatial variability of salts' ions in soils of oases of Weigan River-Kuqa River to explore spatial correlation among soil ions and effects of seasonal changes on distribution of eight ions in soils. [Method] Based on soil salinizaiton, temporal and spatial distributions of eight ions in surface soils were researched and distribution maps were drawn with the help of classical statistics and geostatistics. [Result] All contents of salt ions were proved in consistent with normal distribution by K-S test, and variability of the ions changed with season, for example, variability of ions in soils in October was higher than that in April, which might be caused by little rainfall and high evaporation in October. It can be concluded from semivariance analysis that salt ions were all of high spatial autocorrelation. In addition, it can be concluded from spatial distribution that spatial structures of most ions are reasonable, except Ca2+ and Mg2' in soils collected in April of 2010 and Mg2+ in October of 2010, which were more suitable for linear model, and chloride-sulfate dominated in salinized soils in the researching area. [Conclusion] The research laid foundation for partition, improvement and use of salin- ized soils in delta of Weigan River-Kuqa River.

  2. Asymmetric hydration structure around calcium ion restricted in micropores fabricated in activated carbons

    Science.gov (United States)

    Ohkubo, Takahiro; Kusudo, Tomoko; Kuroda, Yasushige

    2016-11-01

    The adsorbed phase and hydration structure of an aqueous solution of Ca(NO3)2 restricted in micropores fabricated in activated carbons (ACs) having different average pore widths (0.63 and 1.1 nm) were investigated with the analysis of adsorption isotherms and x-ray absorption fine structure (XAFS) spectra on Ca K-edge. The adsorbed density of Ca2+ per unit micropore volume in the narrower pore was higher than in the wider pore, while the adsorbed amount per unit mass of carbon with the narrower pore was half of the amount of ACs with the larger pore. On the other hand, variations in the bands assigned to double-electron (KM I) and 1s  →  3d excitations in XAFS spectra demonstrate the formation of a distorted hydration cluster around Ca2+ in the micropore, although the structural parameters of hydrated Ca2+ in the micropores were almost consistent with the bulk aqueous solution, as revealed by the analysis of extended XAFS (EXAFS) spectra. In contrast to the hydration structure of monovalent ions such as Rb+, which generally presents a dehydrated structure in smaller than 1 nm micropores in ACs, the present study clearly explains that the non-spherically-symmetric structure of hydrated Ca2+ restricted in carbon micropores whose sizes are around 1 nm is experimentally revealed where any dehydration phenomena from the first hydration shell around Ca2+ could not be observed.

  3. Lithium recovery by means of electrochemical ion pumping: a comparison between salt capturing and selective exchange.

    Science.gov (United States)

    Trocoli, Rafael; Bidhendi, Ghoncheh Kasiri; La Mantia, Fabio

    2016-03-23

    Currently, lithium carbonate is mainly produced through evaporation of lithium-rich brines, which are located in South American countries such as Bolivia, Chile, and Argentina. The most commonly used process, the lime-soda evaporation, requires a long time and several purification steps, which produces a considerable amount of chemical waste. Recently, several alternative electrochemical methods, based on LiFePO4 as a selective lithium capturing electrode and differing for the reaction at the counter electrode, have been proposed. In this work a comparison between the salt capturing method, based on silver / silver chloride reaction, and the selective exchange method, based on ion intercalation reaction in a Prussian Blue derivative, is performed in terms of energy consumption. In particular, the energy consumption is divided in thermodynamic and kinetic contribution, and the theoretical calculations are compared with the experimental results. The experimental results show a good agreement with the theoretical calculation. The selective exchange method shows superior performances to the salt exchange in terms of purity and efficiency, however the energy consumption is higher. PMID:26910577

  4. Lithium recovery by means of electrochemical ion pumping: a comparison between salt capturing and selective exchange

    International Nuclear Information System (INIS)

    Currently, lithium carbonate is mainly produced through evaporation of lithium-rich brines, which are located in South American countries such as Bolivia, Chile, and Argentina. The most commonly used process, the lime–soda evaporation, requires a long time and several purification steps, which produces a considerable amount of chemical waste. Recently, several alternative electrochemical methods, based on LiFePO4 as a selective lithium capturing electrode and differing for the reaction at the counter electrode, have been proposed. In this work a comparison between the salt capturing method, based on silver / silver chloride reaction, and the selective exchange method, based on ion intercalation reaction in a Prussian Blue derivative, is performed in terms of energy consumption. In particular, the energy consumption is divided in thermodynamic and kinetic contribution, and the theoretical calculations are compared with the experimental results. The experimental results show a good agreement with the theoretical calculation. The selective exchange method shows superior performances to the salt exchange in terms of purity and efficiency, however the energy consumption is higher. (paper)

  5. Observation of a sequential process in charge-asymmetric dissociation of CO2q + (q =4 ,5 ) upon the impact of highly charged ions

    Science.gov (United States)

    Khan, Arnab; Tribedi, Lokesh C.; Misra, Deepankar

    2015-09-01

    The dynamics involved in three-body breakup of carbon dioxide upon the impact of 1-MeV Ar8 + ions is investigated. Among the six possible fragmentation channels of CO2q + (q =4 ,5 ) , where all fragments are charged, two charge-asymmetric fragmentation channels show evidence of a sequential breakup process. It has been observed that the molecular structures tend towards deformed geometry as the initial charge on the precursor molecular ion increases. The total energy deposition to the system is found to play a key role in deciding between different breakup pathways.

  6. ZIF-8 Derived, Nitrogen-Doped Porous Electrodes of Carbon Polyhedron Particles for High-Performance Electrosorption of Salt Ions.

    Science.gov (United States)

    Liu, Nei-Ling; Dutta, Saikat; Salunkhe, Rahul R; Ahamad, Tansir; Alshehri, Saad M; Yamauchi, Yusuke; Hou, Chia-Hung; Wu, Kevin C-W

    2016-01-01

    Three-dimensional (3-D) ZIF-8 derived carbon polyhedrons with high nitrogen (N) content, (denoted as NC-800) are synthesized for their application as high-performance electrodes in electrosorption of salt ions. The results showed a high specific capacitance of 160.8 F·g(-1) in 1 M NaCl at a scan rate of 5 mV·s(-1). Notably, integration of 3-D mesopores and micropores in NC-800 achieves an excellent capacitive deionization (CDI) performance. The electrosorption of salt ions at the electrical double layer is enhanced by N-doping at the edges of a hexagonal lattice of NC-800. As evidenced, when the initial NaCl solution concentration is 1 mM, the resultant NC-800 exhibits a remarkable CDI potential with a promising salt electrosorption capacity of 8.52 mg·g(-1). PMID:27404086

  7. ZIF-8 Derived, Nitrogen-Doped Porous Electrodes of Carbon Polyhedron Particles for High-Performance Electrosorption of Salt Ions

    Science.gov (United States)

    Liu, Nei-Ling; Dutta, Saikat; Salunkhe, Rahul R.; Ahamad, Tansir; Alshehri, Saad M.; Yamauchi, Yusuke; Hou, Chia-Hung; Wu, Kevin C.-W.

    2016-01-01

    Three-dimensional (3-D) ZIF-8 derived carbon polyhedrons with high nitrogen (N) content, (denoted as NC-800) are synthesized for their application as high-performance electrodes in electrosorption of salt ions. The results showed a high specific capacitance of 160.8 F·g−1 in 1 M NaCl at a scan rate of 5 mV·s−1. Notably, integration of 3-D mesopores and micropores in NC-800 achieves an excellent capacitive deionization (CDI) performance. The electrosorption of salt ions at the electrical double layer is enhanced by N-doping at the edges of a hexagonal lattice of NC-800. As evidenced, when the initial NaCl solution concentration is 1 mM, the resultant NC-800 exhibits a remarkable CDI potential with a promising salt electrosorption capacity of 8.52 mg·g−1. PMID:27404086

  8. Calculation of activities of ions in molten salts with potential application to the pyroprocessing of nuclear waste.

    Science.gov (United States)

    Salanne, Mathieu; Simon, Christian; Turq, Pierre; Madden, Paul A

    2008-01-31

    The ability to separate fission products by electrodeposition from molten salts depends, in part, on differences between the interactions of the different fission product cations with the ions present in the molten salt "solvent". These differences may be expressed as ratios of activity coefficients, which depend on the identity of the solvent and other factors. Here, we demonstrate the ability to calculate these activity coefficient ratios using molecular dynamics simulations with sufficient precision to guide the choice of suitable solvent systems in practical applications. We use polarizable ion interaction potentials which have previously been shown to give excellent agreement with structural, transport, and spectroscopic information of the molten salts, and the activity coefficients calculated in this work agree well with experimental data. The activity coefficients are shown to vary systematically with cation size for a set of trivalent cations.

  9. On-line method to study dynamics of ion adsorption from mixtures of salts in capacitive deionization

    NARCIS (Netherlands)

    Dykstra, J.E.; Dijkstra, J.; Wal, van der A.; Hamelers, H.V.M.; Porada, S.

    2016-01-01

    Capacitive Deionization (CDI) is a water desalination technology that adsorbs ions into two oppositely polarized porous carbon electrodes, under the action of an applied voltage. Here, we introduce a novel method to analyze the effluent concentration of multiple ionic species in mixtures of salt

  10. Combination of Metal Coordination Tetrahedra and Asymmetric Coordination Geometries of Sb(III) in the Organically Directed Chalcogenidometalates: Structural Diversity and Ion-exchange Properties.

    Science.gov (United States)

    Feng, Mei-Ling; Wang, Kai-Yao; Huang, Xiao-Ying

    2016-04-01

    Chalcogenidometalates exhibit rich and diverse structures and properties applicable to ion exchange, thermoelectrics, photocatalysis, nonlinear optics, and so on. This personal account summarizes our recent progress in constructing chalcogenidometalates by combining metal coordination tetrahedra and the asymmetric coordination geometries of Sb(3+) in the presence of organic species (typically organic amines and metal-organic amine complexes), which has been demonstrated as an effective strategy for synthesizing chalcogenidometalates with diversified structures and interesting properties. The linkage modes of asymmetric SbQn (n = 3, 4) geometries and group 13 (or 14) metal coordination tetrahedra are analyzed, and the secondary building units (SBUs), with different compositions and architectures, are clarified. The crucial role and function of organic species in the formation of chalcogenidometalates are explored, with an emphasis on their powerful structure-directing features. In particular, some chalcogenidometalates in this family exhibit excellent ion-exchange properties for Cs(+) and/or Sr(2+) ions; the factors affecting ion-exchange properties are discussed to understand the underlying ion-exchange mechanism.

  11. Elucidation of transport mechanism and enhanced alkali ion transference numbers in mixed alkali metal-organic ionic molten salts.

    Science.gov (United States)

    Chen, Fangfang; Forsyth, Maria

    2016-07-28

    Mixed salts of Ionic Liquids (ILs) and alkali metal salts, developed as electrolytes for lithium and sodium batteries, have shown a remarkable ability to facilitate high rate capability for lithium and sodium electrochemical cycling. It has been suggested that this may be due to a high alkali metal ion transference number at concentrations approaching 50 mol% Li(+) or Na(+), relative to lower concentrations. Computational investigations for two IL systems illustrate the formation of extended alkali-anion aggregates as the alkali metal ion concentration increases. This tends to favor the diffusion of alkali metal ions compared with other ionic species in electrolyte solutions; behavior that has recently been reported for Li(+) in a phosphonium ionic liquid, thus an increasing alkali transference number. The mechanism of alkali metal ion diffusion via this extended coordination environment present at high concentrations is explained and compared to the dynamics at lower concentrations. Heterogeneous alkali metal ion dynamics are also evident and, somewhat counter-intuitively, it appears that the faster ions are those that are generally found clustered with the anions. Furthermore these fast alkali metal ions appear to correlate with fastest ionic liquid solvent ions. PMID:27375042

  12. LITERATURE REVIEWS TO SUPPORT ION EXCHANGE TECHNOLOGY SELECTION FOR MODULAR SALT PROCESSING

    Energy Technology Data Exchange (ETDEWEB)

    King, W

    2007-11-30

    This report summarizes the results of literature reviews conducted to support the selection of a cesium removal technology for application in a small column ion exchange (SCIX) unit supported within a high level waste tank. SCIX is being considered as a technology for the treatment of radioactive salt solutions in order to accelerate closure of waste tanks at the Savannah River Site (SRS) as part of the Modular Salt Processing (MSP) technology development program. Two ion exchange materials, spherical Resorcinol-Formaldehyde (RF) and engineered Crystalline Silicotitanate (CST), are being considered for use within the SCIX unit. Both ion exchange materials have been studied extensively and are known to have high affinities for cesium ions in caustic tank waste supernates. RF is an elutable organic resin and CST is a non-elutable inorganic material. Waste treatment processes developed for the two technologies will differ with regard to solutions processed, secondary waste streams generated, optimum column size, and waste throughput. Pertinent references, anticipated processing sequences for utilization in waste treatment, gaps in the available data, and technical comparisons will be provided for the two ion exchange materials to assist in technology selection for SCIX. The engineered, granular form of CST (UOP IE-911) was the baseline ion exchange material used for the initial development and design of the SRS SCIX process (McCabe, 2005). To date, in-tank SCIX has not been implemented for treatment of radioactive waste solutions at SRS. Since initial development and consideration of SCIX for SRS waste treatment an alternative technology has been developed as part of the River Protection Project Waste Treatment Plant (RPP-WTP) Research and Technology program (Thorson, 2006). Spherical RF resin is the baseline media for cesium removal in the RPP-WTP, which was designed for the treatment of radioactive waste supernates and is currently under construction in Hanford, WA

  13. Synthesis and Self-Assembly of Triangulenium Salts

    DEFF Research Database (Denmark)

    Shi, Dong

    This thesis describes the design and synthesis of asymmetrically substituted amphiphilic tis(dialkylamino)trioxiatriangulenium (ATOTA+) salts with different counter ions. Attention was focused on exploring the assembling properties of the ATOTA+ salts in aqueous media. A direct vortexing......-processed self-assembling method was developed to make aggregates with uniform morphologies and excellent stabilities in an equilibrium state either with pure ATOTA+ salts or with mixed systems of ATOTA+ salts and lipid molecules in aqueous media. Special emphasis was given to effects of the counterions......-assembly and triangulenium salts. Chapters 3 to 6 are mainly focused on the synthesis and self-assembly of trioxatriangulenium salts in aqueous media. In particular, chapter 3 reports a direct selfassembly of a synthetic triangulenium salt mixed with DMPC lipid (5/95 by molar ratio) to make mono disperse bilayer vesicles...

  14. Titratable Macroions in Multivalent Electrolyte Solutions: Strong Coupling Dressed Ion Approach

    CERN Document Server

    Adzic, Natasa

    2016-01-01

    We present a theoretical description of the effect of polyvalent ions on the interaction between titratable macro-ions. The model system consists of two point-like macro-ions with dissociable sites, immersed in an asymmetric ionic mixture of monovalent and polyvalent salts. We formulate a {\\em dressed ion strong coupling theory}, based on the decomposition of the asymmetric ionic mixture into a weakly electrostatically coupled monovalent salt, and into polyvalent ions that are strongly electrostatically coupled to the titratable macro-ions. The charge of the macroions is not considered as fixed, but is allowed to respond to local bathing solution parameters (electrostatic potential, $pH$ of the solution, salt concentration) through a simple {\\em charge regulation} model. The approach presented, yielding an effective polyvalent-ion mediated interaction between charge-regulated macro-ions at various solution conditions, describes the strong coupling equivalent of the Kirkwood-Schumaker interaction.

  15. Effect of NaCl on growth and ion relations in two salt-tolerant strains of Paxillus involutus

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua; WANG Mei-juan; LU Yan-jun; LI Li-si; Rosemarie LANGENFELD-HEYSER; Fritz EBERHARD; Andrea POLLE; LI Jing; CHEN Shao-liang; LU Cun-fu; WANG Rui-gang; DAI Song-xiang; ZHU Hui-juan; ZHANG Yun-xia; SHI Yong

    2008-01-01

    The effect of NaCl on growth, biomass and ion relations of two salt-tolerant isolates of Paxillus involutus, MAJ and NAU were investigated. The two Paxillus strains were exposed to the following concentrations of NaCl: 0, 100, 200 and 500 mmol·L-1. Growth of MAJ and NAU was enhanced by 100 mmol·L-1 NaCl but severely inhibited at the concentration of 500 mmol·L-1. NAU exhibited a greater capacity to exclude Na+ and Cl- under all salinity levels, whereas the salt-includer MAJ had a higher capacity in nutrient uptake under salt stress. The ratios Na+/K+, Na+/Ca2+ and Na+/Mg2+ in NaCl-treated MAJ and NAU did not increase at levels of 100 and 200 mmol·L-1 NaCl but markedly increased at 500 mmol·L-1. This suggests that the two strains, especially MAJ, enhanced nutrient uptake corresponding to the increased Na+ influx at moderate salinity. We conclude that both MAJ and NAU are able to tolerate 500 mmol·L-1 NaCl but there arc species-specific differences in retaining ionic homeostasis in the two Paxillus strains. NAU is a salt-excluder, MAJ is a salt-includer but retains a high capacity in nutrient selectivity under saline conditions. Their definite mechanisms to enhance salt tolerance of mycorrhizal hosts need further study.

  16. New boron based salts for lithium-ion batteries using conjugated ligands.

    Science.gov (United States)

    Jankowski, P; Wieczorek, W; Johansson, P

    2016-06-28

    A new anion design concept, based on combining a boron atom as the central atom and conjugated systems as ligands, is presented as a route for finding alternative Li-salts for lithium-ion batteries. The properties of a wide range of novel anions designed in this way have been evaluated by DFT calculations focusing on three different fundamental success factors/measures: the strength of the cation-anion interaction, ultimately determining both the solubility and the ionic conductivity, the oxidation limit, determining their possible use vs. high voltage cathodes, and the reduction stability, revealing a possible role of the anion in the SEI-formation at the anode. For a few anions superior properties vs. today's existing or suggested anions are predicted, especially the very low cation-anion interaction strengths are promising features. The design route itself is shown to be versatile in determining the correlation between different choices of ligands and the resulting overall properties - where the most striking feature is the decreased lithium cation interaction energy upon using the (1Z,3Z)-buta-1,3-diene-1,2,3,4-tetracarbonitrile ligands. This also opens avenues for the further design of novel anions beyond those with a boron central atom. PMID:27253752

  17. Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation of Sodium Salts

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A.; Bonnesen, Peter V.; Custelcean, Radu; Delmau, Laetitia H.; Engle, Nancy L.; Kang, Hyun-Ah; Keever, Tamara J.; Marchand, Alan P.; Gadthula, Srinivas; Gore, Vinayak K.; Huang, Zilin; Sivappa, Rasapalli; Tirunahari, Pavan K.; Levitskaia, Tatiana G.; Lumetta, Gregg J.

    2005-09-26

    The purpose of this research involving collaboration between Oak Ridge National Laboratory (ORNL) and Pacific Northwest National Laboratory (PNNL) is to explore new approaches to the separation of sodium hydroxide, sodium nitrate, and other sodium salts from high-level alkaline tank waste. The principal potential benefit is a major reduction in disposed waste volume, obviating the building of expensive new waste tanks and reducing the costs of vitrification. Principles of ion recognition are being researched toward discovery of liquid-liquid extraction systems that selectively separate sodium hydroxide and sodium nitrate from other waste components. The successful concept of pseudo hydroxide extraction using fluorinated alcohols and phenols is being developed at ORNL and PNNL toward a greater understanding of the controlling equilibria, role of solvation, and of synergistic effects involving crown ethers. Synthesis efforts are being directed toward enhanced sodium binding by crown ethers, both neutral and proton-ionizable. Studies with real tank waste at PNNL will provide feedback toward solvent compositions that have promising properties.

  18. Simultaneous removal of organic matter and salt ions from saline wastewater in bioelectrochemical systems

    KAUST Repository

    Kim, Younggy

    2013-01-01

    A new bioelectrochemical system is proposed for simultaneous removal of salinity and organic matter. In this process, exoelectrogenic microorganisms oxidize organic matter and transfer electrons to the anode, hydrogen is evolved at the cathode by supplying additional voltage, and salt is removed from the wastewater due to the electric potential generated and the use of two ion-exchange membranes. Salinity removal (initial conductivity ~40mS/cm) increased from 21 to 84% by increasing the substrate (sodium acetate) from 2 to 8g/L. A total of 72-94% of the chemical oxygen demand was degraded in the anode and cathode chambers, with 1-4% left in the anode chamber and the balance lost through the anion-exchange membrane into the concentrate waste chamber. The maximum hydrogen production rate was 3.6m3-H2/m3-electrolyte per day at an applied potential of 1.2V. The Coulombic efficiency was ~100%, while the cathode recovery varied from 57 to 100%, depending on the extent of methanogenesis. Exoelectrogenic microbes generated high current densities (7.8mA/cm2) at ≤36g/L of total dissolved solids, but >41g/L eliminated current. These results provide a new method for achieving simultaneous removal of salinity and organic matter from a saline wastewater with H2 production. © 2012 Elsevier B.V.

  19. Secretion by the nasal salt glands of two insectivorous lizard species is initiated by an ecologically relevant dietary ion, chloride.

    Science.gov (United States)

    Hazard, Lisa C; Lechuga, Claudia; Zilinskis, Stephanie

    2010-08-01

    Salt glands are used by some vertebrates to excrete hyperosmotic NaCl or KCl solutions in response to dietary salt loads. Control of secretion varies across taxa; some secrete in response to osmotic challenges while others secrete in response to specific dietary ions. We hypothesized that differences in control could be related to different diet-related selective pressures on herbivorous, marine, and insectivorous species. We studied control of secretion and flexibility of cation (sodium or potassium) and anion (chloride or bicarbonate) secretion in two insectivorous lizard species, Schneider's skinks (Eumeces schneideri, Scincidae) and green anoles (Anolis carolinensis, Polychrotidae). Lizards were injected daily for four days with combinations of cations (potassium, sodium, and histidine control) and anions (chloride and acetate control), isoosmotic saline, or sham injection. Secretions were collected daily and analyzed for sodium, potassium, and chloride. Both species secreted only in response to chloride; sodium appeared to have a slight inhibitory effect. Regardless of cation load, skinks secreted a combination of potassium and sodium, while anoles secreted solely potassium. In both species, total cation secretion was matched closely by chloride; very little bicarbonate was secreted. As predicted, secretion in insectivorous lizards was initiated by the dietary ion ecologically most important for these species, chloride, which otherwise cannot be excreted without significant water loss (unlike the cations, which may be excreted as insoluble urate salts). This gives further support to the hypothesis that ecological factors drive the evolution of control mechanisms in lizard salt glands. PMID:20623801

  20. Analysis of trace inorganic anions in weak acid salts by single pump cycling-column-switching ion chromatography.

    Science.gov (United States)

    Huang, Zhongping; Ni, Chengzhu; Zhu, Zhuyi; Pan, Zaifa; Wang, Lili; Zhu, Yan

    2015-05-01

    The application of ion chromatography with the single pump cycling-column-switching technique was described for the analysis of trace inorganic anions in weak acid salts within a single run. Due to the hydrogen ions provided by an anion suppressor electrolyzing water, weak acid anions could be transformed into weak acids, existing as molecules, after passing through the suppressor. Therefore, an anion suppressor and ion-exclusion column were adopted to achieve on-line matrix elimination of weak acid anions with high concentration for the analysis of trace inorganic anions in weak acid salts. A series of standard solutions consisting of target anions of various concentrations from 0.005 to 10 mg/L were analyzed, with correlation coefficients r ≥ 0.9990. The limits of detection were in the range of 0.67 to 1.51 μg/L, based on the signal-to-noise ratio of 3 and a 25 μL injection volume. Relative standard deviations for retention time, peak area, and peak height were all less than 2.01%. A spiking study was performed with satisfactory recoveries between 90.3 and 104.4% for all anions. The chromatographic system was successfully applied to the analysis of trace inorganic anions in five weak acid salts.

  1. Influences of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen and soil salt-ion leaching

    Institute of Scientific and Technical Information of China (English)

    YU Qiaogang; YE Xuezhu; CHEN Yingxu; ZHANG Zhijian; TIAN Guangming

    2008-01-01

    An undisturbed heavy clay soil column experiment was conducted to examine the influence of the new nitrification inhibitor,3,4-dimethylpyrazole phosphate (DMPP),on nitrogen and soil salt-ion leaching.Regular urea was selected as the nitrogen source in the soil.The results showed that the cumulative leaching losses of soil nitrate-N under the treatment of urea with DMPP were from 57.5% to 63.3% lower than those of the treatment of urea without DMPP.The use of nitrification inhibitors as nitrate leaching retardants may be a proposal in regulations to prevent groundwater contaminant.However,there were no great difference between urea and urea with DMPP treatments on ammonium-N leaching.Moreover,the soil salt-ion leaching losses of Ca2+,Mg2+,K+,and Na+ were reduced from 26.6% to 28.8%,21.3% to 27.8%,33.3% to 35.5%,and 21.7% to 32.1%,respectively.So,the leaching losses of soil salt-ion were declined for nitrification inhibitor DMPP addition,being beneficial to shallow groundwater protection and growth of crop.These results indicated the possibility of ammonium or ammonium producing compounds using nitrification inhibitor DMPP to control the nitrate and nutrient cation leaching losses,minimizing the risk of nitrate pollution in shallow groundwater.

  2. The optimal composition of sorbents on the basis of iso- and hetero-polyacid salts for selective concentration of inorganic ions

    International Nuclear Information System (INIS)

    Present article is devoted to selection of optimal composition of sorbents on the basis of iso- and hetero-polyacid salts for selective concentration of inorganic ions. Thus, several options are proposed and considered.

  3. Direct Analysis of Oil Additives by High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometry Combined with Electrospray Ionization and Desorption Electrospray Ionization.

    Science.gov (United States)

    Da Costa, Caitlyn; Turner, Matthew; Reynolds, James C; Whitmarsh, Samuel; Lynch, Tom; Creaser, Colin S

    2016-02-16

    The analysis of corrosion inhibitors in the presence and absence of an oil matrix is reported using electrospray ionization (ESI) and desorption electrospray ionization (DESI), hyphenated with miniaturized high-field asymmetric waveform ion mobility spectrometry (FAIMS) and mass spectrometry (MS). The target analytes were successfully ionized in solution by ESI and directly from steel surfaces using DESI ambient ionization at levels ≥0.0004% w/w (4 ppm) in oil. Differences in the mass spectral profiles observed for the additive/oil mixture are attributed to differences between the ESI and DESI ionization processes. The use of FAIMS improved selectivity for ESI generated analyte ions through reduction in the chemical noise resulting from the oil matrix. DESI enabled the direct, rapid, native state interrogation of oil samples on steel surfaces without sample pretreatment, and the hyphenation of DESI with the miniaturized FAIMS enhanced the relative analyte responses of the surface-active corrosion inhibitors. PMID:26780580

  4. Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

    Science.gov (United States)

    Y. A. Kaassis, Abdessamad; Xu, Si-Min; Guan, Shanyue; Evans, David G.; Wei, Min; Williams, Gareth R.

    2016-06-01

    The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co1.2Zn3.8(OH)8](NO3)2·2H2O (CoZn-NO3), [Ni2Zn3(OH)8](NO3)2·2H2O (NiZn-NO3) and [Zn5(OH)8](NO3)2·2H2O (Zn-NO3). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO3 but when it was reacted with Zn-NO3 the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an "X" shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO3 and Zn-NO3 is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO3 and of Val into CoZn-NO3 are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles.

  5. Strain evolution in Si substrate due to implantation of MeV ion observed by extremely asymmetric x-ray diffraction

    Science.gov (United States)

    Emoto, T.; Ghatak, J.; Satyam, P. V.; Akimoto, K.

    2009-08-01

    We studied the strain introduced in a Si(111) substrate due to MeV ion implantation using extremely asymmetric x-ray diffraction and measured the rocking curves of asymmetrical 113 diffraction for the Si substrates implanted with a 1.5 MeV Au2+ ion at fluence values of 1×1013, 5×1013, and 1×1014/cm2. The measured curves consisted of a bulk peak and accompanying subpeak with an interference fringe. The positional relationship of the bulk peak to the subpeak and the intensity variation of those peaks with respect to the wavelengths of the x rays indicated that crystal lattices near the surface were strained; the lattice spacing of surface normal (111) planes near the surface was larger than that of the bulk. Detailed strain profiles along the depth direction were successfully estimated using a curve-fitting method based on Darwin's dynamical diffraction theory. Comparing the shapes of resultant strain profiles, we found that a strain evolution rapidly occurred within a depth of ˜300 nm at fluence values between 1×1013 and 5×1013/cm2. This indicates that formation of the complex defects progressed near the surface when the fluence value went beyond a critical value between 1×1013 and 5×1013/cm2 and the defects brought a large strain to the substrate.

  6. A Systematic Investigation of Quaternary Ammonium Ions as Asymmetric Phase Transfer Catalysts. Application of Quantitative Structure Activity/Selectivity Relationships

    OpenAIRE

    Denmark, Scott E.; Gould, Nathan D.; Wolf, Larry M

    2011-01-01

    While the synthetic utility of asymmetric phase transfer catalysis continues to expand, the number of proven catalyst types and design criteria remains limited. At the origin of this scarcity is a lack in understanding of how catalyst structural features affect the rate and enantioselectivity of phase transfer catalyzed reactions. Described in this paper is the development of quantitative structure-activity relationships (QSAR) and -selectivity relationships (QSSR) for the alkylation of a pro...

  7. Evaluation of ion mobility spectroscopy for determining charge-solvated versus salt-bridge structures of protonated trimers.

    Science.gov (United States)

    Wong, Richard L; Williams, Evan R; Counterman, Anne E; Clemmer, David E

    2005-07-01

    The cross sections of five different protonated trimers consisting of two base molecules and trifluoroacetic acid were measured by using ion mobility spectrometry. The gas-phase basicities of these five base molecules span an 8-kcal/mol range. These cross sections are compared with those determined from candidate low-energy salt-bridge and charge-solvated structures identified by using molecular mechanics calculations using three different force fields: AMBER*, MMFF, and CHARMm. With AMBER*, the charge-solvated structures are all globular and the salt-bridge structures are all linear, whereas with CHARMm, these two forms of the protonated trimers can adopt either shape. Globular structures have smaller cross sections than linear structures. Conclusions about the structure of these protonated trimers are highly dependent on the force field used to generate low-energy candidate structures. With AMBER*, all of the trimers are consistent with salt-bridge structures, whereas with MMFF the measured cross sections are more consistent with charge-solvated structures, although the assignments are ambiguous for two of the protonated trimers. Conclusions based on structures generated by using CHARMm suggest a change in structure from charge-solvated to salt-bridge structures with increasing gas-phase basicity of the constituent bases, a result that is most consistent with structural conclusions based on blackbody infrared radiative dissociation experiments for these protonated trimers and theoretical calculations on the uncharged base-acid pairs.

  8. Salt Tolerance

    OpenAIRE

    Xiong, Liming; Zhu, Jian-Kang

    2002-01-01

    Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are sh...

  9. Adiabatic and sudden interaction potentials in the fusion-fission of heavy ion collisions: Asymmetric target-projectile combinations

    International Nuclear Information System (INIS)

    It is now well known that many reactions giving measurable fusion cross-sections also show a fission of the compound system formed, similar to the low energy fission of the known fissioning nuclei. Recently, both the fusion excitation functions and the mass equilibration in the fragmentation of the composite system were measured for a large number of systems with 94208Pb on different targets of 26Mg, 48Ca, 50Ti, 52Cr, 58Fe and 64Ni. From a theoretical point of view, it is relevant to ask the question: how do the colliding nuclei fuse and then why does the compound system formed fission instead of going to the ground state to give a stable system. In this Letter, we attempt to show that the fusion of asymmetric colliding nuclei is due to the overcoming of the interaction barriers in adiabatic potentials and the fission of the compound system should perhaps occur as a sudden process, like the one in the spontaneous fission phenomenon. We have made our calculations for the compound systems with 102<=Z<=110 and for the asymmetric target-projectile combinations of the experiments of Ref. 1, using the fragmentation theory whose basis is the asymmetric two-centre shell model

  10. Lithium salt with a super-delocalized perfluorinated sulfonimide anion as conducting salt for lithium-ion cells: Physicochemical and electrochemical properties

    Science.gov (United States)

    Zhang, Heng; Han, Hongbo; Cheng, Xiaorong; Zheng, Liping; Cheng, Pengfei; Feng, Wenfang; Nie, Jin; Armand, Michel; Huang, Xuejie; Zhou, Zhibin

    2015-11-01

    Lithium salt with a super-delocalized imide anion, namely (trifluoromethane(S-trifluoromethanesulfonylimino)sulfonyl) (trifluoromethanesulfonyl)imide ([CF3SO(=NSO2CF3)2]-), [sTFSI]-), has been prepared and studied as conducting salt for Li-ion cells. The fundamental physicochemical and electrochemical properties of neat Li[sTFSI] and its carbonate-based liquid electrolyte have been characterized with various chemical and electrochemical tools. Li[sTFSI] shows a low melting point at 118 °C, and is thermally stable up to 300 °C without decomposition on the spectra of differential scanning calorimetry-thermogravimetry-mass spectrometry (DSC-TG-MS). The electrolyte of 1.0 M (mol dm-3) Li[sTFSI] in ethylene carbonate (EC)/ethyl-methyl-carbonate (EMC) (3:7, v/v) containing 0.3% water does not show any hydrolytic decomposition on the spectra of 1H and 19F NMR, after storage at 85 °C for 10 days. The conductivities of 1.0 M Li[sTFSI]-EC/EMC (3:7, v/v) are slightly lower than those of Li[(CF3SO2)2N] (LiTFSI), but higher than those of Li[(C2F5SO2)2N] (LiBETI). The electrochemical behavior of Al foil in the Li[sTFSI]-based electrolyte has been investigated by using cyclic voltammetry and chronoamperometry, and scanning electron microscope (SEM). It is illustrated that Al metal does not corrode in the high potential region (3-5 V vs. Li/Li+) in the Li[sTFSI]-based electrolyte. On Pt electrode, the Li[sTFSI]-based electrolyte is highly resistant to oxidation (ca. 5 V vs. Li/Li+), and is also resistant to reduction to allow Li deposition and stripping. The applicability of Li[sTFSI] as conducting salt for Li-ion cells has been tested using graphite/LiCoO2 cells. It shows that the cell with Li[sTFSI] displays better cycling performance than that with LiPF6.

  11. Liquid electrolyte based on lithium bis-fluorosulfonyl imide salt: Aluminum corrosion studies and lithium ion battery investigations

    Energy Technology Data Exchange (ETDEWEB)

    Abouimrane, A.; Ding, J.; Davidson, I.J. [Institute for Chemical Process and Environmental Technology, National Research Council Canada, 1200 Montreal Road, Ottawa K1A 0R6 (Canada)

    2009-04-01

    The performance of a liquid electrolyte composed of lithium bis-fluorosulfonyl imide (LiSFI) in a 1:1 volume of ethylene carbonate and dimethyl carbonate is evaluated for use in lithium ion batteries. Imide salts offer the benefits of higher thermal stability and could provide a safer alternative to LiPF{sub 6} which is prone to the formation of HF. However, the most studied lithium imide salt, lithium bis(trifluoromethanesulfonyl) imide, is well known to have a problem with corrosion of aluminum which is commonly used as the cathode current collector. Consequently, the corrosion properties of liquid electrolytes based on lithium bis-fluorosulfonyl imide are also investigated. (author)

  12. Changes in Transcript Related to Osmosis and Intracellular Ion Homeostasis in Paulownia tomentosa under Salt Stress

    OpenAIRE

    Fan, Guoqiang; Wang, Limin; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng; Zhang, Xiaoshen; Li, Yongsheng

    2016-01-01

    Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through t...

  13. The 2-D Ion Chromatography Development and Application: Determination of Sulfate in Formation Water at Pre-Salt Region

    Science.gov (United States)

    Tonietto, G. B.; Godoy, J. M.; Almeida, A. C.; Mendes, D.; Soluri, D.; Leite, R. S.; Chalom, M. Y.

    2015-12-01

    Formation water is the naturally-occurring water which is contained within the geological formation itself. The quantity and quality of the formation water can both be problematic. Over time, the water volume should decrease as the gas volumes increase. Formation water has been found to contain high levels of Cl, As, Fe, Ba, Mn, PAHs and may even contain naturally occurring radioactive materials. Chlorides in some cases have been found to be in excess of four-five times the level of concentrations found in the ocean. Within the management of well operation, there is sulfate between the analytes of greatest importance due to the potential for hydrogen sulphide formation and consequent corrosion of pipelines. As the concentration of sulfate in these waters can be less than n times that of chloride, a quantitative determination, using the technique of ion chromatography, constitutes an analytical challenge. This work aimed to develop and validate a method for the determination of sulphate ions in hyper-saline waters coming from the oil wells of the pre-salt, using 2D IC. In 2D IC the first column can be understood as a separating column, in which the species with retention times outside a preset range are discarded, while those belonging to this range are retained in a pre-concentrator column to further injecting a second column, the second dimension in which occurs the separation and quantification of the analytes of interest. As the chloride ions have a retention time lower than that of sulfate, a method was developed a for determining sulfate in very low range (mg L-1) by 2D IC, applicable to hypersaline waters, wherein the first dimension is used to the elimination of the matrix, ie, chloride ions, and the second dimension utilized in determining sulfate. For sulphate in a concentration range from 1.00 mg L-1 was obtained an accuracy of 1.0%. The accuracy of the method was tested by the standard addition method different samples of formation water in the pre-salt

  14. High-field asymmetric waveform ion mobility spectrometry for determining the location of in-source collision-induced dissociation in electrospray ionization mass spectrometry.

    Science.gov (United States)

    Xia, Yuan-Qing; Jemal, Mohammed

    2009-09-15

    The understanding and control of the in-source collision-induced dissociation (CID) of analytes is important for the accurate LC-MS/MS quantitation of drugs and metabolites in biological samples. Accordingly, it was of interest to us to establish whether such in-source CID takes place after and/or before the orifice of an electrospray ionization (ESI) mass spectrometer. A high-field asymmetric waveform ion mobility spectrometry (FAIMS) system that is physically located between the sprayer and the orifice of a mass spectrometer can serve as an ion filter to control ions entering the orifice of the mass spectrometer. In such a configuration, FAIMS could conceivably be used to determine if the in-source CID of an analyte occurs after and/or before the mass spectrometer orifice. We demonstrated this capability of FAIMS using ifetroban acylglucuronide metabolite as a model compound. Under the conditions used, the results showed that the in-source CID conversion of the acylglucuronide metabolite to its parent drug ifetroban occurred almost entirely after the orifice of the mass spectrometer, with the conversion upstream of the orifice accounting for only 5.6% of the conversion. Under the circumstance, the term "post-orifice CID" rather than "in-source CID" may be more appropriate in describing such a dissociation occurring in the front end of a mass spectrometer.

  15. Titratable macroions in multivalent electrolyte solutions: Strong coupling dressed ion approach

    Science.gov (United States)

    Adžić, Nataša; Podgornik, Rudolf

    2016-06-01

    We present a theoretical description of the effect of polyvalent ions on the interaction between titratable macroions. The model system consists of two point-like macroions with dissociable sites, immersed in an asymmetric ionic mixture of monovalent and polyvalent salts. We formulate a dressed ion strong coupling theory, based on the decomposition of the asymmetric ionic mixture into a weakly electrostatically coupled monovalent salt and into polyvalent ions that are strongly electrostatically coupled to the titratable macro-ions. The charge of the macroions is not considered as fixed, but is allowed to respond to local bathing solution parameters (electrostatic potential, pH of the solution, and salt concentration) through a simple charge regulation model. The approach presented, yielding an effective polyvalent-ion mediated interaction between charge-regulated macroions at various solution conditions, describes the strong coupling equivalent of the Kirkwood-Schumaker interaction.

  16. Syntheses and Application of All-lithium Salts of Heteropolyacid as Electrolyte of Lithium-ion Battery

    Institute of Scientific and Technical Information of China (English)

    CHEN Ya-guang; WANG Cun-guo; ZHANG Xi-yan; XIE De-min; WANG Rong-shun

    2004-01-01

    The all-lithium salts of heteropoly acid LixXM12O40(HPA-Li)(X=P, Si; M=Mo, W) were obtained via ion exchange and characterized by means of IR and UV spectroscopies, TG and elemental analyses. The conductivity of the electrolytic solution consisting of Li3PW12O40 and PC/DME mixing solvent(1/2.5, volume ratio) is up to 7.2×10-2 S/cm, being higher than that of LiClO4 as the electrolyte. The all-lithium salts were used as electrolytes in secondary lithium-ion batteries. The discharge capacity of the PAS/Li batteries with Li3PW12O40 electrolyte solutions reaches to 148 (mA*h)/g and the cyclic life is up to 380 times, much better than those of commercialized products with LiClO4 and LiAsF6 as electrolytes.

  17. Thermal stability of LiPF 6 salt and Li-ion battery electrolytes containing LiPF 6

    Science.gov (United States)

    Yang, Hui; Zhuang, Guorong V.; Ross, Philip N.

    The thermal stability of the neat lithium hexafluorophosphate (LiPF 6) salt and of 1 molal (m) solutions of LiPF 6 in prototypical Li-ion battery solvents was studied with thermogravimetric analysis (TGA) and on-line Fourier transform infrared (FTIR). Pure LiPF 6 salt is thermally stable up to 107 °C in a dry inert atmosphere, and its decomposition path is a simple dissociation producing lithium fluoride (LiF) as solid and PF 5 as gaseous products. In the presence of water (300 ppm) in the carrier gas, its decomposition onset temperature is lowered as a result of direct thermal reaction between LiPF 6 and water vapor to form phosphorous oxyfluoride (POF 3) and hydrofluoric acid (HF). No new products were observed in 1 m solutions of LiPF 6 in ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) by on-line TGA-FTIR analysis. The storage of the same solutions in sealed containers at 85 °C for 300-420 h did not produce any significant quantity of new products as well. In particular, no alkylflurophosphates were found in the solutions after storage at elevated temperature. In the absence of either an impurity like alcohol or cathode active material that may (or may not) act as a catalyst, there is no evidence of thermally induced reaction between LiPF 6 and the prototypical Li-ion battery solvents EC, PC, DMC or EMC.

  18. Interaction modes between asymmetrically and oppositely charged rods.

    Science.gov (United States)

    Antila, Hanne S; Van Tassel, Paul R; Sammalkorpi, Maria

    2016-02-01

    The interaction of oppositely and asymmetrically charged rods in salt-a simple model of (bio)macromolecular assembly-is observed via simulation to exhibit two free energy minima, separated by a repulsive barrier. In contrast to similar minima in the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the governing mechanism includes electrostatic attraction at large separation, osmotic repulsion at close range, and depletion attraction near contact. A model accounting for ion condensation and excluded volume is shown to be superior to a mean-field treatment in predicting the effect of charge asymmetry on the free-energy profile. PMID:26986372

  19. Interaction modes between asymmetrically and oppositely charged rods.

    Science.gov (United States)

    Antila, Hanne S; Van Tassel, Paul R; Sammalkorpi, Maria

    2016-02-01

    The interaction of oppositely and asymmetrically charged rods in salt-a simple model of (bio)macromolecular assembly-is observed via simulation to exhibit two free energy minima, separated by a repulsive barrier. In contrast to similar minima in the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the governing mechanism includes electrostatic attraction at large separation, osmotic repulsion at close range, and depletion attraction near contact. A model accounting for ion condensation and excluded volume is shown to be superior to a mean-field treatment in predicting the effect of charge asymmetry on the free-energy profile.

  20. Analysis of triazines and associated metabolites with electrospray ionization field-asymmetric ion mobility spectrometry/mass spectrometry

    DEFF Research Database (Denmark)

    Mie, Axel; Sandulescu, Madaline; Mathiasson, Lennart;

    2008-01-01

    Triazines comprise an important pollutant class owing to continued use in certain countries, and owing to strong environmental persistence that leads to problems even in countries like Sweden where the use of triazines has been prohibited for some years. We investigated mass-selective detection...... for ion sorting and discrimination against the considerable "chemical noise", nonspecific cluster and fragment ions, which are typically generated in electrospray ionization. This paper presents results of a pilot study of triazines and some metabolites in ideal solvents. Our long-range goal is automated...

  1. A systematic investigation of quaternary ammonium ions as asymmetric phase-transfer catalysts. Application of quantitative structure activity/selectivity relationships.

    Science.gov (United States)

    Denmark, Scott E; Gould, Nathan D; Wolf, Larry M

    2011-06-01

    Although the synthetic utility of asymmetric phase-transfer catalysis continues to expand, the number of proven catalyst types and design criteria remains limited. At the origin of this scarcity is a lack in understanding of how catalyst structural features affect the rate and enantioselectivity of phase transfer catalyzed reactions. Described in this paper is the development of quantitative structure-activity relationships (QSAR) and -selectivity relationships (QSSR) for the alkylation of a protected glycine imine with libraries of quaternary ammonium ion catalysts. Catalyst descriptors including ammonium ion accessibility, interfacial adsorption affinity, and partition coefficient were found to correlate meaningfully with catalyst activity. The physical nature of the descriptors was rationalized through differing contributions of the interfacial and extraction mechanisms to the reaction under study. The variation in the observed enantioselectivity was rationalized employing a comparative molecular field analysis (CoMFA) using both the steric and electrostatic fields of the catalysts. A qualitative analysis of the developed model reveals preferred regions for catalyst binding to afford both configurations of the alkylated product.

  2. The salts of chloronium ions R-Cl(+)-R (R = CH3 or CH2Cl): formation, thermal stability, and interaction with chloromethanes.

    Science.gov (United States)

    Stoyanov, Evgenii S

    2016-05-14

    The interaction of CH3Cl/CD3Cl or CH2Cl2/CD2Cl2 with the carborane acid H(CHB11Cl11) (abbreviated as H{Cl11}) generates the salts of CH3-{Cl11} and CH2Cl-{Cl11} and their deuterio analogs, respectively, which are analogs of the salts of asymmetric chloronium cations. Next, salts of chloronium cations CH3-Cl(+)-CH3, ClCH2-Cl(+)-CH2Cl, and ClCH2-Cl(+)-CH3 and their deuterio analogs were obtained from the above compounds. The asymmetric ClCH2-Cl(+)-CH3 cation was found to be unstable, and at ambient temperature, slowly disproportionated into symmetric cations (CH3)2Cl(+) and (CH2Cl)2Cl(+). At a high temperature (150 °C), disproportionation was completed within 5 minutes, and the resulting cations further decomposed into CH3-{Cl11} and CH2Cl-{Cl11}. The molecular fragment ClCH2-(X) of the compounds (X = {Cl11}, -Cl(+)-CH2Cl, or -Cl(+)-CH3) is involved in exchange reactions with CH2Cl2 and CHCl3, converting into CH3-(X) with the formation of chloroform and CCl4, respectively. PMID:27104946

  3. Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions

    Directory of Open Access Journals (Sweden)

    Kohzo Yoshida

    2010-11-01

    Full Text Available Organoammonium salts composed of a Brønsted acid and an anilinothiourea promoted the Michael addition of β-keto esters and α,β-unsaturated aldehydes in the presence of primary amines to give functionalized 1,4-dihydropyridines enantioselectively. With the use of the different Brønsted acids such as DFA and HBF4 with the same bifunctional thiourea, both enantiomers of 4-substituted 1,4-dihydropyridine were synthesized from the same starting materials.

  4. Ion exchange reactions in amorphous and crystalline aluminium silicates from solution of cerium salts

    International Nuclear Information System (INIS)

    Reactions of ion-exchange of Na+ by Ce3+ and NH4+ on the zeolite containing catalyst, amorphous silica alumina and zeolite Y have been studied. The cerium cations are shown to be exchanged by the Na+ cations with more selectivity than the anmonia cations. In the case of the zeolite containing catalyst and amorphous silica alumina the region of the staggered ion-exchange from the mixture of the solutions of cerium and ammonium sulphates was been detected. This is explained by the formation fo cerium complexes with the sulphate ions

  5. The salt and lipid composition of model cheeses modifies in-mouth flavour release and perception related to the free sodium ion content.

    Science.gov (United States)

    Boisard, Lauriane; Andriot, Isabelle; Martin, Christophe; Septier, Chantal; Boissard, Vanessa; Salles, Christian; Guichard, Elisabeth

    2014-02-15

    Reducing salt and lipid levels in foodstuffs without any effect on acceptability is a major challenge, particularly because of their interactions with other ingredients. This study used a multimodal approach to understand the effects of changes to the composition of model cheeses (20/28, 24/24, 28/20 lipid/protein ratios, 0% and 1% added NaCl) on sodium ion mobility ((23)Na NMR), in-mouth sodium release and flavour perception. An increase in the salt content decreased cheese firmness and perceived hardness, and increased sodium ion mobility, in vivo sodium release and both saltiness and aroma perception. With the same amount of salt, a lower lipid/protein ratio increased the firmness of the cheeses, perceived hardness, and decreased sodium ion mobility, in vivo sodium release, saltiness and aroma perception. These findings suggest on one hand that it could be possible to increase saltiness perception by varying cheese composition, thus inducing differences in sodium ion mobility and in free sodium ion concentration, leading to differences in in-mouth sodium release and saltiness perception, and on the other hand that the reformulation of foods in line with health guidelines needs to take account of both salt content and the lipid/protein ratio. PMID:24128499

  6. Dietary salt loading and ion-poor water exposure provide insight into the molecular physiology of the rainbow trout gill epithelium tight junction complex.

    Science.gov (United States)

    Kolosov, Dennis; Kelly, Scott P

    2016-08-01

    This study utilized dietary salt loading and ion-poor water (IPW) exposure of rainbow trout (Oncorhynchus mykiss) to further understand the role of fish gill epithelium tight junction (TJ) physiology in salt and water balance. Gill morphology, biochemistry and molecular physiology were examined, with an emphasis on genes encoding TJ proteins. Fish were either fed a control or salt-enriched diet (~10 % NaCl) for 4 weeks prior to IPW exposure for 24 h. Serum [Na(+)], [Cl(-)] and muscle moisture content were unaltered by salt feeding, but changed in response to IPW irrespective of diet. Dietary salt loading altered the morphology (reduced Na(+)-K(+)-ATPase-immunoreactive cell numbers and surface exposure of mitochondrion-rich cells), biochemistry (decreased vacuolar-type H(+)-ATPase activity) and molecular physiology (decreased nkaα1a and cftrII mRNA abundance) of the gill in a manner indicative of reduced active ion uptake activity. But in control fish and not salt-fed fish, gill mRNA abundance of nkaα1c increased and nbc decreased after IPW exposure. Genes encoding TJ proteins were typically either responsive to salt feeding or IPW, but select genes responded to combined experimental treatment (e.g. IPW responsive but only if fish were salt-fed). Therefore, using salt feeding and IPW exposure, new insights into what factors influence gill TJ proteins and the role that specific TJ proteins might play in regulating the barrier properties of the gill epithelium have been acquired. In particular, evidence suggests that TJ proteins in the gill epithelium, or the regulatory networks that control them, respond independently to external or internal stimuli. PMID:27083431

  7. Interfacial behavior of perchlorate versus chloride ions in saturated aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosal, S; Kuo, I W; Baer, M D; Bluhm, H

    2009-04-14

    In recent years combination of theoretical and experimental work have presented a novel view of the aqueous interface wherein hard and/or multiply charged ions are excluded from the interface, but large polarizable anions show interfacial enhancement relative to the bulk. The observed trend in the propensity of anions to adsorb at the air/water interface appears to be reverse of the Hofmeister series for anions. This study focuses on experimental and theoretical examination of the partitioning behavior of perchlorate (ClO{sub 4}{sup -}) and chloride (Cl{sup -}) ions at the air/water interface. We have used ambient pressure X-ray photoelectron spectroscopy technique to directly probe the interfacial concentrations of ClO{sub 4}{sup -} and Cl{sup -} ions in sodium perchlorate and sodium chloride solutions, respectively. Experimental observations are compared with first principles molecular dynamics simulations. Both experimental and simulation results show enhancement of ClO{sub 4}{sup -} ion at the interface, compared with the absence of such enhancement in the case of Cl{sup -} ion. These observations are in agreement with the expected trend in the interfacial propensity of anions based on the Hofmeister series.

  8. Structure characterization and electrochemical properties of new lithium salt LiODFB for electrolyte of lithium ion batteries

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Lithium difluoro(axalato)borate (LiODFB) was synthesized in dimethyl carbonate (DMC) solvent and purified by the method of solventing-out crystallization.The structure characterization of the purified LiODFB was performed by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) spectrometry.The electrochemical properties of the cells using I mol/L LiPF6 and 1 mol/L LiODFB in ethylene carbonate (EC)/DMC were investigated,respectively.The results indicate that LiODFB can be reduced at about 1.5 V and form a robust protective solid electrolyte interface (SEI) film on the graphite surface in the first cycle.The graphite/LiNi1/3Mn1/3Co1/3O2 cells with LiODFB-based electrolyte have very good capacity retention at 55 ℃,and show very good rate capability at 0.5C and 1C charge/discharge rate.Therefore,as a new salt,LiODFB is a most promising alternative lithium salt to replace LiPF6 for lithium ion battery electrolytes in the future.

  9. Complex polyion-surfactant ion salts in equilibrium with water: changing aggregate shape and size by adding oil.

    Science.gov (United States)

    Bernardes, Juliana S; Norrman, Jens; Piculell, Lennart; Loh, Watson

    2006-11-23

    The phase behavior of ternary mixtures containing an alkyltrimethylammonium polyacrylate complex salt, water, and a nonpolar "oil" (n-decanol, p-xylene or cyclohexane) is investigated. The complex salts were prepared with short or long polyacrylates (30 or 6000 repeating units) and with hexadecyltrimethylammonium or dodecyltrimethylammonium surfactant ions. Phase diagrams and structures were determined by visual inspection and small-angle X-ray scattering analyses. Systems containing decanol display a predominance of lamellar phases, while hexagonal phases prevail in systems containing p-xylene or cyclohexane. The difference is interpreted as a result of the different locations of the oils within the surfactant aggregates. Decanol is incorporated at the aggregate interface, leading to a decrease in its curvature, which favors the appearance of lamellar structures. p-Xylene and cyclohexane, on the other hand, are mostly incorporated in the interior of the cylindrical aggregate, as reflected by its swelling as the oil content increases. The comparison of these results with those reported for similar systems with monovalent (bromide) counterions indicates a much more limited swelling of the lamellar phases with polymeric counterions by water. This limited swelling behavior is predominantly ascribed to bridging due to the polyions. PMID:17107195

  10. Calcium ion activity in physiological salt solutions: influence of anions substituted for chloride

    DEFF Research Database (Denmark)

    Christoffersen, Gert Rene Juul; Skibsted, Leif H

    1975-01-01

    1. Substitution by different anions for chloride in physiological salt solutions leads to binding between Ca2+ and the anion. Experiments designed to test effects of Cl- therefore often show mixed effects of changes in Cl- and Ca2+ activity.   2. This mixed effect is demonstrated in neurons...... of the snail, Helix pomatia: current-voltage characteristics and membrane potential are described during reduction of extracellular Cl- using different anions as substitutes. Methylsulphate is concluded to be the best substitute in this preparation. 3. The association constants for the binding of Ca2...

  11. Variation in viscosity and ion conductivity of a polymer–salt complex exposed to gamma irradiation

    Indian Academy of Sciences (India)

    Sujata Tarafdar; S K De; Sujit Manna; Udayan De; Pradyot Nanda

    2010-02-01

    We study changes in microstructure and resulting changes in the properties of PEO(1 − )–NH4 ClO4 () samples where = 0.18, when irradiated with gamma doses varying up to 50 kGy. Viscosities of aqueous solutions of the irradiated samples give an idea of the change in molecular weight and show correlation with ion conductivity. On the whole, there is a chain scission on irradiation, though there is evidence of some cross-linking at higher doses. The ion conductivity shows a strong increase for an irradiation of 35 kGy. DSC studies indicate a decrease in crystallinity with gamma dose.

  12. Interactive toxicity of major ion salts: Comparisons among species and between acute and chronic endpoints

    Science.gov (United States)

    Increased concentrations of major ions (Na, K, Ca, Mg, Cl, SO4, HCO3) in freshwater systems can result from a variety of anthropogenic activities, and can adversely affect aquatic organisms if the increase is sufficiently severe. Laboratory tests have indicated that the toxicity...

  13. Synthesis of rock-salt type lithium borohydride and its peculiar Li+ ion conduction properties

    Directory of Open Access Journals (Sweden)

    R. Miyazaki

    2014-05-01

    Full Text Available The high energy density and excellent cycle performance of lithium ion batteries makes them superior to all other secondary batteries and explains why they are widely used in portable devices. However, because organic liquid electrolytes have a higher operating voltage than aqueous solution, they are used in lithium ion batteries. This comes with the risk of fire due to their flammability. Solid electrolytes are being investigated to find an alternative to organic liquid. However, the nature of the solid-solid point contact at the interface between the electrolyte and electrode or between the electrolyte grains is such that high power density has proven difficult to attain. We develop a new method for the fabrication of a solid electrolyte using LiBH4, known for its super Li+ ion conduction without any grain boundary contribution. The modifications to the conduction pathway achieved by stabilizing the high pressure form of this material provided a new structure with some LiBH4, more suitable to the high rate condition. We synthesized the H.P. form of LiBH4 under ambient pressure by doping LiBH4 with the KI lattice by sintering. The formation of a KI - LiBH4 solid solution was confirmed both macroscopically and microscopically. The obtained sample was shown to be a pure Li+ conductor despite its small Li+ content. This conduction mechanism, where the light doping cation played a major role in ion conduction, was termed the “Parasitic Conduction Mechanism.” This mechanism made it possible to synthesize a new ion conductor and is expected to have enormous potential in the search for new battery materials.

  14. Stable isotopes and major ion chemistry of continental salt lakes from southern Spain

    International Nuclear Information System (INIS)

    In several lakes from Southern of Spain, the parameters geochemical and isotopic (oxygen 18 and deuterium) have been studied. The main objective was establish the hydrological regimen by analysing the relationship between surface and groundwater in the different lakes using both isotopic and the hydrochemical characteristics of their waters and to quantify the degree of correlation between these variables. Lakes are systems that, although complex as is every natural system, are well fitted to the study of environmental isotopes. The origin and subsequent evaporative process of natural waters can be determined by the investigation of the relationship between the oxygen and hydrogen isotopes. A total of four lakes have been selected and according to the results obtained, the hydrological dynamics and the relation between salinity and isotopic content within the lakes studied could be determined. Two main hydrologic models have been established: a) Lakes with a mainly epigenetic hydrologic regime, in which very high isotopic contents are not found, seeing as, they have not had continuous evaporite processes, but instead have frequently dried up in summer (temporary lakes). In such systems a 'reflux brine' appears under the lake basin, and the brine magnitude is in proportion to the extension of the lake. It may be added that, even though the surface runoff is the main recharge component in the hydrologic cycle, these systems have some groundwater recharge when the piezometric levels are above the free water level and, so, they can store water even in low or zero precipitation periods in which, otherwise, they would dry up. In this way, an accurate classification would be epigenetic-mixed. b) Lakes in which the water shows several evaporite cycles. These kind of lakes do not have a very high salt content, but a very high isotopic content. They are permanent lakes in which the principal water balance component is groundwater. The classification is hypogenic, according

  15. Stable isotopes and major ion chemistry of continental salt lakes from Southern Spain

    International Nuclear Information System (INIS)

    Full text: In several lakes from Southern of Spain, the parameters geochemical and isotopic (δ18O and δ2H) have been studied. The main objective was establish the hydrological regimen by analysing the relationship between surface and groundwater in the different lakes using both isotopic and the hydrochemical characteristics of their waters and to quantify the degree of correlation between these variables. Lakes are systems that, although complex as is every natural system, are well fitted to the study of environmental isotopes. The origin and subsequent evaporative process of natural waters can be determined by the investigation of the relationship between the oxygen and hydrogen isotopes. A total of four lakes have been selected and according to the results obtained, the hydrological dynamics and the relation between salinity and isotopic content within the lakes studied could be determined. Two main hydrologic models have been established: a) Lakes with a mainly epigenetic hydrologic regime, in which very high isotopic contents are not found, seeing as, they have not had continuous evaporite processes, but instead have frequently dried up in summer (temporary lakes). In such systems a 'reflux brine' appears under the lake basin, and the brine magnitude is in proportion to the extension of the lake. It may be added that, even though the surface runoff is the main recharge component in the hydrologic cycle, these systems have some groundwater recharge when the piezometric levels are above the free water level and, so, they can store water even in low or zero precipitation periods in which, otherwise, they would dry up. In this way, an accurate classification would be epigenetic-mixed; b) Lakes in which the water shows several evaporite cycles. These kind of lakes do not have a very high salt content, but a very high isotopic content. They are permanent lakes in which the principal water balance component is groundwater. The classification is hypogenic, according

  16. Electrochemical co-reduction between aluminium and lanthanide ions in fluoride salts: application to nuclear wastes pyrochemical treatment

    International Nuclear Information System (INIS)

    Nuclear reaction produces fission products such as lanthanides; these neutro-phage elements represent a poison for the nuclear chain reaction and have to be extracted. This thesis concerns lanthanides extraction (neodymium, cerium and samarium) by electrodeposition in the LiF-CaF2 eutectic mixture at 840 C. The process used is an alloy formation with aluminium by electrochemical co-reduction on an inert tungsten electrode. This technique is based on the simultaneous reduction of Al(III) and Ln(III) ions to obtain an alloy at the cathode. A decrease of the lanthanide activity in the alloy is obtained due to Al-Ln formation and a shift of lanthanide reduction potential to more positive values is observed: the theoretical extraction efficiency is then approaching 100 %. When both Ln(III) and Al(III) ions are present in the molten salt, new reduction waves appear between Al and Ln pure metal depositions and are attributed to Al-Ln alloy formation by co-reduction. The alloy compositions have been characterised in function of electrolysis potential: the more the electrolysis potential is negative, higher is the Ln content in the alloy. Finally, extractions by potentiostatic electrolyses have been carried out and the extraction efficiencies for the different lanthanides are higher than 99.4 %. (author)

  17. Preparation of hybrid polymer based on polyurethane lithium salt and polyvinylidene fluoride as electrolyte for lithium-ion batteries

    International Nuclear Information System (INIS)

    Graphical abstract: The hybrid microporous membrane (PVDF/PLS-10) presents a uniform morphology and the corresponding HMGPE delivers high electrochemical stability and excellent cycleability. - Abstract: In this paper, hybrid microporous gel polymer electrolytes (HMGPEs) based onpolyvinylidene fluoride (PVdF)/polyurethane lithium salt (PLS) are fabricated by thermal phase separation technique. PLS is synthesized via condensation copolymerization of polyethylene glycol 800 (PEG800) and diphenyl-methane-diisocyanate(MDI), and then neutralized with LiOH. The effect of PLS on the morphologies of the hybrid membrane, electrochemical properties and cycle performance of the assembled polymer lithium-ion rechargeable batteries are studied in detail. The morphologies of the hybrid polymer membranes are examined by scanning electron microscope (SEM). The intercalation of PVdF/PLS hybrid membranes is characterized by X-ray diffraction (XRD), differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). The incorporation of PLS in PVdF matrix can enhance ionic conductivities and electrochemical stabilities for the prepared HMGPEs. The assembled lithium-ion batteries based on HMGPEs with weight ratio 80:20 of PVdF and PLS (PVdF/PLS-20) delivers the highest charge-discharge capacity (about 175mAh g−1), and the cell based on HMGPEs of with weight ratio 90:10 of PVdF and PLS(PVdF/PLS-10) shows the best stability in cycle performance

  18. Molten salt synthesis of sodium lithium titanium oxide anode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.Y., E-mail: yshy2004@hotmail.com [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Feng, C.Q. [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry of Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules, Hubei University, Wuhan 430062 (China); Wu, S.J.; Liu, H.L.; Ke, B.Q. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Zhang, K.L. [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Chen, D.H. [College of Environmental and Biological Engineering, Wuhan Technology and Business University, Wuhan 430065 (China); Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South Central University for Nationalities, Wuhan 430074, Hubei (China)

    2015-09-05

    Highlights: • Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} has been successfully synthesized via a molten salt route. • Calcination temperature is an important effect on the component and microstructure of the product. • Pure phase Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 12} could be obtained at 700 °C for 2 h. - Abstract: The sodium lithium titanium oxide with composition Na{sub 2}Li{sub 2}Ti{sub 6}O{sub 14} has been synthesized by a molten salt synthesis method using sodium chloride and potassium chloride mixture as a flux medium. Synthetic variables on the synthesis, such as sintering temperature, sintering time and the amount of lithium carbonate, were intensively investigated. Powder X-ray diffraction and scanning electron microscopy images of the reaction products indicates that pure phase sodium lithium titanium oxide has been obtained at 700 °C, and impure phase sodium hexatitanate with whiskers produced at higher temperature due to lithium evaporative losses. The results of cyclic voltammetry and discharge–charge tests demonstrate that the synthesized products prepared at various temperatures exhibited electrochemical diversities due to the difference of the components. And the sample obtained at 700 °C revealed highly reversible insertion and extraction of Li{sup +} and displayed a single potential plateau at around 1.3 V. The product obtained at 700 °C for 2 h exhibits good cycling properties and retains the specific capacity of 62 mAh g{sup −1} after 500 cycles.

  19. Effect of phytohormones on absorption and distribution of ions in salt-stressed bean plants

    Directory of Open Access Journals (Sweden)

    Zofia Starck

    2014-02-01

    Full Text Available Bean plant seedlings grown in water culture were treated for 5 days either with NaCl or with 7-times concentrated nutrient solution (diminished water potential by 3-103 hPa in both cases. Control and stressed plants were treated for 24 hrs with zeatin and GA,. NaCl-stress reduced distinctly ion absorption rate (K, Ca and P. Zeatin and GA3 promoted potassium uptake, but only in NaCI-treated plants. These hormones diminished Na accumulation in metabolically active organs but increased P- and Ca-content. In plants grown under both kind of stresses zeatin and GA3 partially reestablished the ratio of the main mono- to divalent cations, which increased in the leaves and apical part of the stressed plants. ABA introduced into the nutrient solution caused inhibition of the ion uptake (K, Ca, Mg and P. similar to that caused by NaCl-stress. The above reported results seem to confirm the supposition, that hormones act as an important factor contributing to regulation of both uptake and distribution of ions. In this way growth substances may also participate in the regulation of transport of various substances (among others - assimilates in the whole plant.

  20. 3-(Dicyanomethylidene)indan-1-one-Functionalized Calix[4]arene-Calix[4]pyrrole Hybrid: An Ion-Pair Sensor for Cesium Salts.

    Science.gov (United States)

    Yeon, Yerim; Leem, Soojung; Wagen, Corin; Lynch, Vincent M; Kim, Sung Kuk; Sessler, Jonathan L

    2016-09-01

    A chromogenic calix[4]arene-calix[4]pyrrole hybrid ion pair receptor bearing an indane substituent at a β-pyrrolic position has been prepared. On the basis of solution-phase UV-vis spectroscopic analysis and (1)H NMR spectroscopic studies carried out in 10% methanol in chloroform, receptor 1 is able to bind only cesium ion pairs (e.g., CsF, CsCl, and CsNO3) but not the constituent cesium cation (as its perchlorate salt) or the F(-), Cl(-), or NO3(-) anions (as the tetrabutylammonium salts). It thus displays rudimentary AND logic gate behavior. Receptor 1 shows a colorimetric response to cesium ion pairs under conditions of solid-liquid (nitrobenzene) and liquid-liquid (D2O-nitrobenzene-d5) extraction. PMID:27533478

  1. Change of electrostatic potential of mean force between two curved surfaces due to different salt composition, ion valence and size under certain ionic strength

    Science.gov (United States)

    Zhou, Shiqi

    2016-02-01

    Change of an electrostatic potential of mean force (EPMF) between two cylindrical rod surfaces with salt composition, ion valence, and ion size at a constant ionic strength of 0.3 M is studied by a classical density functional theory (CDFT) in a primitive model electrolyte solution. Several novel observations are made: (i) strength of a so-called like charge attraction (LCA) reduces in an invariable manner with the salt solution changing from single 2:1 electrolyte to mixture of 2:1 and 1:1 type electrolytes of varying concentration ratios; the change is even over entire range of the composition variation under low surface charge strength, and tends to be insensitive to the composition variation in the presence of the divalent counter-ion, and more and more drastic at a critical point the divalent counter-ion disappears, respectively, as the surface charge strength becomes big enough. (ii) Both monovalent counter-ion and co-ion diameters have only a marginal effect on both the LCA strength and equilibrium distance, and the former "abnormally" affects less than the latter. (iii) Depending on the surface charge strength considered, the divalent counter-ion diameter influences the LCA strength in solution comprised of 2:1 type and 1:1 type electrolytes, monotonously or non-monotonously. All of these findings provide forceful support for a recently proposed hydrogen-bonding style mechanism explaining the LCA.

  2. Increased abscisic acid levels in transgenic maize overexpressing AtLOS5 mediated root ion fluxes and leaf water status under salt stress.

    Science.gov (United States)

    Zhang, Juan; Yu, Haiyue; Zhang, Yushi; Wang, Yubing; Li, Maoying; Zhang, Jiachang; Duan, Liusheng; Zhang, Mingcai; Li, Zhaohu

    2016-03-01

    Abscisic acid (ABA) is a vital cellular signal in plants, and effective ABA signalling is pivotal for stress tolerance. AtLOS5 encoding molybdenum cofactor sulphurase is a key regulator of ABA biosynthesis. Here, transgenic AtLOS5 plants were generated to explore the role of AtLOS5 in salt tolerance in maize. AtLOS5 overexpression significantly up-regulated the expression of ZmVp14-2, ZmAO, and ZmMOCO, and increased aldehyde oxidase activities, which enhanced ABA accumulation in transgenic plants under salt stress. Concurrently, AtLOS5 overexpression induced the expression of ZmNHX1, ZmCBL4, and ZmCIPK16, and enhanced the root net Na(+) efflux and H(+) influx, but decreased net K(+) efflux, which maintained a high cytosolic K(+)/Na(+) ratio in transgenic plants under salt stress. However, amiloride or sodium orthovanadate could significantly elevate K(+) effluxes and decrease Na(+) efflux and H(+) influx in salt-treated transgenic roots, but the K(+) effluxes were inhibited by TEA, suggesting that ion fluxes regulated by AtLOS5 overexpression were possibly due to activation of Na(+)/H(+) antiport and K(+) channels across the plasma membrane. Moreover, AtLOS5 overexpression could up-regulate the transcripts of ZmPIP1:1, ZmPIP1:5, and ZmPIP2:4, and enhance root hydraulic conductivity. Thus transgenic plants had higher leaf water potential and turgor, which was correlated with greater biomass accumulation under salt stress. Thus AtLOS5 overexpression induced the expression of ABA biosynthetic genes to promote ABA accumulation, which activated ion transporter and PIP aquaporin gene expression to regulate root ion fluxes and water uptake, thus maintaining high cytosolic K(+) and Na(+) homeostasis and better water status in maize exposed to salt stress. PMID:26743432

  3. A relationship between ion balance and the chemical compounds of salt inclusions found in the Greenland Ice Core Project and Dome Fuji ice cores

    DEFF Research Database (Denmark)

    Johnsen, Sigfus Johann; Dahl-Jensen, Dorthe; Steffensen, Jørgen Peder;

    2008-01-01

    on individual salt inclusions. The abundances in the ice cores are shown to reflect differences in climatic periods (the acidic environment of the Holocene versus the reductive environment of the last glacial maximum) and regional conditions (the marine environment of Antarctica versus the continental....... The dominant compounds depend only on the ion balance and the sequence of chemical reactions. In priority order, the principle salts are calcium sulfate, other sulfates, nitrate, chloride, and carbonate. The chemical abundances deduced by this method agree well with the results of Raman spectroscopy...

  4. Enhanced salt-removal percentage in capacitive deionization with addition of ion-exchange membrane using carbon electrode synthesized with freezing thawing method

    Science.gov (United States)

    Sari, Intan Permata; Endarko

    2016-04-01

    Ion-exchange membrane technology has shown a great potential to enhance the desalting efficiency. Ion-exchange membranes are placed in front of the electrodes so that the charged ions can be selectively passed through the membrane layer and captured by the oppositely charged electrode more quickly, so as to increase the efficiency of desalination. In this research, carbon electrodes have been synthesized from an activated carbon (700 - 1400 m2/g) and polyvinyl alcohol (PVA) as a binder using freezing thawing method. A solution with 180 µS/cm NaCl was pumped to the capacitive deionization (CDI) cell using a Boyu Submersible pump (model SP-601) at a flow rate of 25 mL/min and the voltage was set at 2 V. The result showed that the CDI cell with ion-exchange membrane (MCDI) has the salt removal efficiency greater than the CDI cell without ion-exchange membrane. The salt-removal percentage of MCDI was achieved at 66.36%, meanwhile the CDI cell without ion-exchange membrane resulted in 54.4%.

  5. Scanning ion-selective electrode technique and X-ray microanalysis provide direct evidence of contrasting Na+ transport ability from root to shoot in salt-sensitive cucumber and salt-tolerant pumpkin under NaCl stress.

    Science.gov (United States)

    Lei, Bo; Huang, Yuan; Sun, Jingyu; Xie, Junjun; Niu, Mengliang; Liu, Zhixiong; Fan, Molin; Bie, Zhilong

    2014-12-01

    Grafting onto salt-tolerant pumpkin rootstock can increase cucumber salt tolerance. Previous studies have suggested that this can be attributed to pumpkin roots with higher capacity to limit the transport of Na(+) to the shoot than cucumber roots. However, the mechanism remains unclear. This study investigated the transport of Na(+) in salt-tolerant pumpkin and salt-sensitive cucumber plants under high (200 mM) or moderate (90 mM) NaCl stress. Scanning ion-selective electrode technique showed that pumpkin roots exhibited a higher capacity to extrude Na(+), and a correspondingly increased H(+) influx under 200 or 90 mM NaCl stress. The 200 mM NaCl induced Na(+)/H(+) exchange in the root was inhibited by amiloride (a Na(+)/H(+) antiporter inhibitor) or vanadate [a plasma membrane (PM) H(+) -ATPase inhibitor], indicating that Na(+) exclusion in salt stressed pumpkin and cucumber roots was the result of an active Na(+)/H(+) antiporter across the PM, and the Na(+)/H(+) antiporter system in salt stressed pumpkin roots was sufficient to exclude Na(+) X-ray microanalysis showed higher Na(+) in the cortex, but lower Na(+) in the stele of pumpkin roots than that in cucumber roots under 90 mM NaCl stress, suggesting that the highly vacuolated root cortical cells of pumpkin roots could sequester more Na(+), limit the radial transport of Na(+) to the stele and thus restrict the transport of Na(+) to the shoot. These results provide direct evidence for pumpkin roots with higher capacity to limit the transport of Na(+) to the shoot than cucumber roots. PMID:24813633

  6. Isotherms and Kinetics of Water Vapor Sorption/Desorption for Surface Films of Polyion-Surfactant Ion Complex Salts.

    Science.gov (United States)

    Gustavsson, Charlotte; Piculell, Lennart

    2016-07-14

    Thin films of "complex salts" (CS = ionic surfactants with polymeric counterions) have recently been shown to respond to humidity changes in ambient air by changing their liquid crystalline structure. We here report isotherms and kinetics of water sorption/desorption for ∼10-100 μm films of alkyltrimethylammonium polyacrylate CS, measured in a dynamic gravimetric vapor sorption instrument over a 0-95% relative humidity (RH) range. The sorption per ion pair was similar to that observed for common ionomers. A kinetic model for the water exchange is presented, assuming that the "external" transport between the vapor reservoir and the film surface is rate-determining. The model predicts that the water content, after a small stepwise change of the reservoir RH, should vary exponentially with time, with a time constant proportional to both the slope of the sorption isotherm and the film thickness. These predictions were confirmed for our films over large RH ranges, and the external mass transfer coefficient in our setup was calculated from the experimental data. Expressions derived for the Biot number (ratio of characteristic times for internal and external water transport) for the considered limiting case strongly indicate that external water transport should quite generally affect, or even dominate, the measured kinetics for similarly thin hydrated films. PMID:27327628

  7. Salt-assisted liquid-liquid microextraction of Cr(VI) ion using an ionic liquid for preconcentration prior to its determination by flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    We report on the salt-assisted liquid-liquid microextraction of cationic complexes of Cr(VI) ion using the hydrophilic ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoraborate and potassium hydrogen phosphate. This is a novel, simple, non-toxic and effective technique for sample pretreatment technique that displays large extraction efficiency and represents a new platform where Cr(VI) is complexed with 1,5-diphenylcarbazide (DPC) in sulfuric acid medium. It was applied to the extraction of Cr(VI) in the form of the Cr(VI)-DPC complex prior to its determination by flame atomic absorption spectrometry. Cr(III) ion also can be determined by this procedure after oxidation to Cr(VI). Extraction is mainly affected by the amount of water-soluble IL, the kind and quantity of inorganic salts, by pH and the concentration of DPC. Calibration plots are linear in the range from 3 to 150 μg L-1 of Cr(VI), and the limit of detection is 1. 25 μg L-1. The method was successfully applied to the speciation and determination of trace levels of Cr(III) and Cr(VI) in environmental water samples containing high levels of dissolved salts or food grade salts. (author)

  8. Salts and nutrients present in regenerated waters induce changes in water relations, antioxidative metabolism, ion accumulation and restricted ion uptake in Myrtus communis L. plants.

    Science.gov (United States)

    Acosta-Motos, José R; Alvarez, Sara; Barba-Espín, Gregorio; Hernández, José A; Sánchez-Blanco, María J

    2014-12-01

    The use of reclaimed water (RW) constitutes a valuable strategy for the efficient management of water and nutrients in landscaping. However, RW may contain levels of toxic ions, affecting plant production or quality, a very important aspect for ornamental plants. The present paper evaluates the effect of different quality RWs on physiological and biochemical parameters and the recovery capacity in Myrtus communis L. plants. M. communis plants were submitted to 3 irrigation treatments with RW from different sources (22 weeks): RW1 (1.7 dS m(-1)), RW2 (4.0 dS m(-1)) and RW3 (8.0 dS m(-1)) and one control (C, 0.8 dS m(-1)). During a recovery period of 11 weeks, all plants were irrigated with the control water. The RW treatments did not negatively affect plant growth, while RW2 even led to an increase in biomass. After recovery,only plants irrigated with RW3 showed some negative effects on growth, which was related to a decrease in the net photosynthesis rate, higher Na accumulation and a reduction in K levels. An increase in salinity was accompanied by decreases in leaf water potential, relative water content and gas exchange parameters, and increases in Na and Cl uptake. Plants accumulated Na in roots and restricted its translocation to the aerial part. The highest salinity levels produced oxidative stress, as seen from the rise in electrolyte leakage and lipid peroxidation. The use of regenerated water together with carefully managed drainage practices, which avoid the accumulation of salt by the substrate, will provide economic and environmental benefits.

  9. Mechanism of dissolution of a lithium salt in an electrolytic solvent in a lithium ion secondary battery: a direct ab initio molecular dynamics (AIMD) study.

    Science.gov (United States)

    Tachikawa, Hiroto

    2014-06-01

    The mechanism of dissolution of the Li(+) ion in an electrolytic solvent is investigated by the direct ab initio molecular dynamics (AIMD) method. Lithium fluoroborate (Li(+)BF4(-)) and ethylene carbonate (EC) are examined as the origin of the Li(+) ion and the solvent molecule, respectively. This salt is widely utilized as the electrolyte in the lithium ion secondary battery. The binding of EC to the Li(+) moiety of the Li(+)BF4(-) salt is exothermic, and the binding energies at the CAM-B3LYP/6-311++G(d,p) level for n=1, 2, 3, and 4, where n is the number of EC molecules binding to the Li(+) ion, (EC)n(Li(+)BF4(-)), are calculated to be 91.5, 89.8, 87.2, and 84.0 kcal mol(-1) (per EC molecule), respectively. The intermolecular distances between Li(+) and the F atom of BF4(-) are elongated: 1.773 Å (n=0), 1.820 Å (n=1), 1.974 Å (n=2), 1.942 Å (n=3), and 4.156 Å (n=4). The atomic bond populations between Li(+) and the F atom for n=0, 1, 2, 3, and 4 are 0.202, 0.186, 0.150, 0.038, and 0.0, respectively. These results indicate that the interaction of Li(+) with BF4(-) becomes weaker as the number of EC molecules is increased. The direct AIMD calculation for n=4 shows that EC reacts spontaneously with (EC)3(Li(+)BF4(-)) and the Li(+) ion is stripped from the salt. The following substitution reaction takes place: EC+(EC)3(Li(+)BF4(-))→(EC)4Li(+)-(BF4(-)). The reaction mechanism is discussed on the basis of the theoretical results. PMID:24616076

  10. Asymmetric collider

    International Nuclear Information System (INIS)

    The study of CP violation in beauty decay is one of the key challenges facing high energy physics. Much work has not yielded a definitive answer how this study might best be performed. However, one clear conclusion is that new accelerator facilities are needed. Proposals include experiments at asymmetric electron-positron colliders and in fixed-target and collider modes at LHC and SSC. Fixed-target and collider experiments at existing accelerators, while they might succeed in a first observation of the effect, will not be adequate to study it thoroughly. Giomataris has emphasized the potential of a new approach to the study of beauty CP violation: the asymmetric proton collider. Such a collider might be realized by the construction of a small storage ring intersecting an existing or soon-to-exist large synchrotron, or by arranging collisions between a large synchrotron and its injector. An experiment at such a collider can combine the advantages of fixed-target-like spectrometer geometry, facilitating triggering, particle identification and the instrumentation of a large acceptance, while the increased √s can provide a factor > 100 increase in beauty-production cross section compared to Tevatron or HERA fixed-target. Beams crossing at a non-zero angle can provide a small interaction region, permitting a first-level decay-vertex trigger to be implemented. To achieve large √s with a large Lorentz boost and high luminosity, the most favorable venue is the high-energy booster (HEB) at the SSC Laboratory, though the CERN SPS and Fermilab Tevatron are also worth considering

  11. Evaluation and elimination of inhibitory effects of salts and heavy metal ions on biodegradation of Congo red by Pseudomonas sp. mutant.

    Science.gov (United States)

    Gopinath, Kannappan Panchamoorthy; Kathiravan, Mathur Natarajan; Srinivasan, Raman; Sankaranarayanan, Subramanian

    2011-02-01

    In this study, it was attempted to evaluate the influences and also recommended some elimination methods for inhibitory effects offered by salts and heavy metal ions. Congo red dye solution treated with mutant Pseudomonas sp. was taken as a model system for study. The salts used in this study are NaCl, CaCl(2) and MgSO(4)· 7H(2)O. Though the growth was inhibited at concentrations above 4 g/l, toleration was achieved by acclimatization process. In case of heavy metal ions, Cr (VI) showed low inhibition up to 500 mg/l of concentration, compared to Zn (II) and Cu (II). It was due to the presence of chromium reductase enzyme which was confirmed by SDS-PAGE. Zn (II) and Cu (II) ion inhibitions were eliminated by chelation with EDTA. The critical ion concentrations obtained as per Han-Levenspiel model for Cr (VI), Zn (II) and Cu (II) were 0.8958, 0.3028 and 0.204 g/l respectively.

  12. Geometrical effect on the issue of asymmetric C 1s photoelectron angular distributions detected in coincidence with the fragment ion pairs of CO+–O+ for CO2 molecules

    International Nuclear Information System (INIS)

    We have measured C 1s photoelectron angular distributions (PADs) in coincidence with the CO+–O+ fragment ion pairs of CO2 molecules at the photoelectron energies of 85, 120 and 150 eV. The observed left–right asymmetric PADs have been well reproduced by our theoretical model taking into account the two degenerate zero-point bending vibrations. This leads to a conclusive result on the interpretation of such PADs; although it has been believed so far that they are the molecular frame, in fact they are the recoil frame. (fast track communications)

  13. Interpretation with a Donnan-based concept of the influence of simple salt concentration on the apparent binding of divalent ions to the polyelectrolytes polystyrenesulfonate and dextran sulfate

    Science.gov (United States)

    Marinsky, J.A.; Baldwin, Robert F.; Reddy, M.M.

    1985-01-01

    It has been shown that the apparent enhancement of divalent metal ion binding to polyions such as polystyrenesulfonate (PSS) and dextran sulfate (DS) by decreasing the ionic strength of these mixed counterion systems (M2+, M+, X-, polyion) can be anticipated with the Donnan-based model developed by one of us (J.A.M.). Ion-exchange distribution methods have been employed to measure the removal by the polyion of trace divalent metal ion from simple salt (NaClO4)-polyion (NaPSS) mixtures. These data and polyion interaction data published earlier by Mattai and Kwak for the mixed counterion systems MgCl2-LiCl-DS and MgCl2-CsCl-DS have been shown to be amenable to rather precise analysis by this model. ?? 1985 American Chemical Society.

  14. Ion-specific weak adsorption of salts and water/octanol transfer free energy of a model amphiphilic hexa-peptide

    International Nuclear Information System (INIS)

    An amphiphilic hexa-peptide has been used as a model to quantify how specific ion effects induced by addition of four salts tune the hydrophilic/hydrophobic balance and induce temperature-dependant coacervate formation from aqueous solution. The hexa-peptide chosen is present as a dimer with low transfer energy from water to octanol. Taking sodium chloride as the reference state in the Hofmeister scale, we identify water activity effects and therefore measure the free energy of transfer from water to octanol and separately the free energy associated to the adsorption of chaotropic ions or the desorption of kosmotropic ions for the same amphiphilic peptide. These effects have the same order of magnitude: therefore, both energies of solvation as well as transfer into octanol strongly depend on the nature of the electrolytes used to formulate any buffer. Model peptides could be used on separation processes based on criteria linked to 'Hofmeister' but different from volume and valency. (authors)

  15. The Influence of Nitrate Salts and Complex Metal Ion to Regio-Selective Synthesis of 2-Nitro-5,10,15,20-Tetra-(4-Methoxyphenyl)Porphyrinato Metal

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A series of 2-nitro-5,10,15,20-tetra(4-methoxyphenyl) porphyrinato metals were regioselectively synthesized with nitrate salts as nitrating reagent in acetic acid/acetic anhydride for preparation of 2-substituted porphyrin. The influence of nitrate salts and complex metal ion to the reaction were investigated. The extent of 2-nitration increased with the electronegativity of the central metal. When Cu(NO3)2·3H2O was used as nitrating reagent, almost quantitative yields of 2 nitro porphyrin were obtained in the case of Cu(Ⅱ) or Ni(Ⅱ) chelates, while Zn(Ⅱ) or Mn(Ⅲ) chelates gave 50% and 30% yields respectively. If Zn(NO3)2·10H2O was used as nitrating agent, no product was found for Cu(Ⅱ) or Ni(Ⅱ) chelates, 12% was found for Zn(Ⅱ) chelates. The other metal ion and nitrate salts were also found in quite different influence.

  16. Protein adsorption on novel acrylamido-based polymeric ion-exchangers. III. Salt concentration effects and elution behavior.

    Science.gov (United States)

    Hunter, A K; Carta, G

    2001-09-28

    The effect of salt concentration on the adsorption and desorption of BSA has been determined for a polymeric anion-exchanger based on acrylamido monomers. The material investigated possesses a high adsorption capacity at low salt concentration and the bound protein can be recovered quantitatively at high salt concentrations. The effects of salt on adsorption and desorption rates were evaluated from batch and shallow-bed experiments, and a model was developed to describe the data quantitatively. The adsorption capacity decreases as the salt concentration is increased, but both adsorption and desorption rates increase at higher salt concentrations. The predictability of the behavior of columns packed with this material was examined by comparing model predictions and experimental results obtained in laboratory columns. In general, a good agreement was obtained between predicted and experimental breakthrough and elution profiles, especially in shorter columns. Thus, the model allows a prediction of the effects of column length, mobile phase flow-rate, protein feed concentration, and salt concentration on dynamic capacity, productivity, and on the concentration of product fractions. PMID:11681582

  17. Effectiveness of native and exotic arbuscular mycorrhizal fungi on nutrient uptake and ion homeostasis in salt-stressed Cajanus cajan L. (Millsp.) genotypes.

    Science.gov (United States)

    Garg, Neera; Pandey, Rekha

    2015-04-01

    Soil salinity is an increasing problem worldwide, restricting plant growth and production. Research findings show that arbuscular mycorrhizal (AM) fungi have the potential to reduce negative effects of salinity. However, plant growth responses to AM fungi vary as a result of genetic variation in mycorrhizal colonization and plant growth responsiveness. Thus, profitable use of AM requires selection of a suitable combination of host plant and fungal partner. A greenhouse experiment was conducted to compare effectiveness of a native AM fungal inoculum sourced from saline soil and two single exotic isolates, Funneliformis mossseae and Rhizophagus irregularis (single or dual mix), on Cajanus cajan (L.) Millsp. genotypes (Paras and Pusa 2002) under salt stress (0-100 mM NaCl). While salinity reduced plant biomass and disturbed ionic status in both genotypes, Pusa 2002 was more salt tolerant and ensured higher AM fungal colonization, plant biomass and nutrient content with favourable ion status under salinity. Although all AM fungi reduced negative effects of salt stress, R. irregularis (alone or in combination with F. mosseae) displayed highest efficiency under salinity, resulting in highest biomass, yield, nutrient uptake and improved membrane stability with favourable K(+)/Na(+) and Ca(2+)/Na(+) ratios in the host plant. Higher effectiveness of R. irregularis correlated with higher root colonization, indicating that the symbiosis formed by R. irregularis had more stable viability and efficiency under salt stress. These findings enhance understanding of the functional diversity of AM fungi in ameliorating plant salt stress tolerance and suggest the potential use of R. irregularis for increasing Cajanus cajan productivity in saline soils. PMID:25155616

  18. Mutation Breeding of Salt-tolerant and Ethanol-producing Strain S. cerevisiae H058 by Low-energy Ion Implantation

    Directory of Open Access Journals (Sweden)

    Shoubao Yan

    2014-07-01

    Full Text Available To obtain an industrial strain with high ethanol fermentation efficiency under salted conditions, the wild strain H058 of Saccharomyces cerevisiae was mutated by means of nitrogen ions implantation. Mutagenic effects of strain H058 by low energy N+ ion implantation were studied. A similar “saddle shape” survival curve due to ion beam irradiation appeared again in this study. By repeated screening, a high salt-tolerant and ethanol-producing strain M158 was obtained. Results showed that in medium contained 0, 1.5, 3.0, 4.5, 6.0% NaCl, M158 produced maximal ethanol of 98.3, 97.2, 96.4, 95.6 and 78.3 g/L at 54, 54, 54 and 72 h, respectively. However, the original strain H058 maximal ethanol of 95.2, 90.9, 84.8, 79.4 and 67.5 g/L at 60, 60, 66 and 72 h, respectively. In addition, the ethanol yield (g/g in all of the NaCl concentrations for M158 is 0.492, 0.486, 0.482, 0.48 and 0.392 g/g, respectively, which were higher than those (0.476, 0.455, 0.424, 0.397 and 0.338 g/g, respectively of the original strain H058. The higher production and shorter fermentation period suggest that strain M158 is a good salt-tolerant and ethanol-producing strain.

  19. Application of normal pulse voltammetric technique for on-line monitoring of lanthanide ions in LiCl-KCl molten salt at 773K

    International Nuclear Information System (INIS)

    The applicability of normal pulse voltammetry (NPV) to on-line monitoring of lanthanide ions in a molten salt system has been investigated for use in the pyrochemical process. It was revealed from NPV curves for lanthanides that the limiting currents for lanthanides linearly increased at lanthanide concentration of less than 2.5 wt%. However, it was observed that the concentration dependence of the limiting currents was not linear at higher concentration. It is thought from those results that NPV could be considered as a promising way to monitor concentration of lanthanides in the pyrochgemical process if the concentration range of analytes is properly controlled. (author)

  20. Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

    DEFF Research Database (Denmark)

    Lund Jensen, Kristian; Kristensen, Jesper Toft; Crumrine, Andrew Michael;

    2011-01-01

    Nanochannel ion transport is known to be governed by surface charge at low ionic concentrations. In this paper, we show that this surface charge is typically dominated by hydronium ions arising from dissolution of ambient atmospheric carbon dioxide. Taking the hydronium ions into account, we model...

  1. Phase behavior of polyion-surfactant ion complex salts: effects of surfactant chain length and polyion length.

    Science.gov (United States)

    Svensson, Anna; Norrman, Jens; Piculell, Lennart

    2006-06-01

    The aqueous phase behavior of a series of complex salts, containing cationic surfactants with polymeric counterions, has been investigated by visual inspection and small-angle X-ray scattering (SAXS). The salts were alkyltrimethylammonium polyacrylates, CxTAPAy, based on all combinations of five surfactant chain lengths (C6, C8, C10, C12, and C16) and two lengths of the polyacrylate chain (30 and 6 000 repeating units). At low water contents, all complex salts except C6TAPA6000 formed hexagonal and/or cubic Pm3n phases, with the hexagonal phase being favored by lower water contents. The aggregate dimensions in the liquid crystalline phases changed with the surfactant chain length. The determined micellar aggregation numbers of the cubic phases indicated that the micelles were only slightly aspherical. At high water contents, the C6TAPAy salts were miscible with water, whereas the other complex salts featured wide miscibility gaps with a concentrated phase in equilibrium with a (sometimes very) dilute aqueous solution. Thus, the attraction between oppositely charged surfactant aggregates and polyions decreases with decreasing surfactant chain length, and with decreasing polyion length, resulting in an increased miscibility with water. The complex salt with the longest surfactant chains and polyions gave the widest miscibility gap, with a concentrated hexagonal phase in equilibrium with almost pure water. A decrease in the attraction led to cubic-micellar and micellar-micellar coexistence in the miscibility gap and to an increasing concentration of the complex salt in the dilute phase. For each polyion length, the mixtures for the various surfactant chain lengths were found to conform to a global phase diagram, where the surfactant chain length played the role of an interaction parameter. PMID:16722736

  2. Genetic characterization of Lophopyrum elongatum salt tolerance and associated ion regulation as expressed in bread wheat. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-07

    Lophopyrum elongatum is a highly salt-tolerant relative of wheat. Its salt tolerance is partially expressed in the amphiploid from a cross between wheat cv. Chinese Spring and L. elongatum. Genetic studies showed that the tolerance of gradually imposed salt stress is controlled by L. elongatum chromosomes 3E, 4E, 5E, and 7E and the tolerance of suddenly imposed salt stress by chromosomes 3E, 5E, 6E, and 7E. In wheat, rye, barley, and Dasypyrum, chromosomes of the same homoeologous groups, 3, 5, 6, and 7, were found to control the tolerance of these stress regimes. To gain insight into the physiological mechanisms of salt tolerance by wheat and L. elongatum, accumulation of Na and K, 20 protein amino acids, glycinebetaine, aminobutyrate, all TCA cycle intermediates, oxalate, glycerol-3-P, glyceraldehyde-3-P, pyruvate, lactate, ornithine, taurine, glucose, sucrose and other sugars was examined in the amphiploid and Chinese Spring by gas chromatography and H-NMR.

  3. SEI Formation and Interfacial Stability of a Si Electrode in a LiTDI-Salt Based Electrolyte with FEC and VC Additives for Li-Ion Batteries.

    Science.gov (United States)

    Lindgren, Fredrik; Xu, Chao; Niedzicki, Leszek; Marcinek, Marek; Gustafsson, Torbjörn; Björefors, Fredrik; Edström, Kristina; Younesi, Reza

    2016-06-22

    An electrolyte based on the new salt, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), is evaluated in combination with nano-Si composite electrodes for potential use in Li-ion batteries. The additives fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are also added to the electrolyte to enable an efficient SEI formation. By employing hard X-ray photoelectron spectroscopy (HAXPES), the SEI formation and the development of the active material is probed during the first 100 cycles. With this electrolyte formulation, the Si electrode can cycle at 1200 mAh g(-1) for more than 100 cycles at a coulombic efficiency of 99%. With extended cycling, a decrease in Si particle size is observed as well as an increase in silicon oxide amount. As opposed to LiPF6 based electrolytes, this electrolyte or its decomposition products has no side reactions with the active Si material. The present results further acknowledge the positive effects of SEI forming additives. It is suggested that polycarbonates and a high LiF content are favorable components in the SEI over other kinds of carbonates formed by ethylene carbonate (EC) and dimethyl carbonate (DMC) decomposition. This work thus confirms that LiTDI in combination with the investigated additives is a promising salt for Si electrodes in future Li-ion batteries. PMID:27220376

  4. Characterization of Ion Contents and Metabolic Responses to Salt Stress of Different Arabidopsis AtHKT1;1 Genotypes and Their Parental Strains

    Institute of Scientific and Technical Information of China (English)

    Camilla B.Hill; Deepa Jha; Antony Bacic; Mark Tester; Ute Roessner

    2013-01-01

    Plants employ several strategies to maintain cellular ion homeostasis under salinity stress,including mediating ion fluxes by transmembrane transport proteins and adjusting osmotic pressure by accumulating osmolytes.The HKT (high-affinity potassium transporter) gene family comprises Na+ and Na+/K+ transporters in diverse plant species,with HKT1;1 as the only member in Arabidopsis thaliana.Cell-type-specific overexpression of AtHKT1;1 has been shown to prevent shoot Na+ overaccumulation under salinity stress.Here,we analyzed a broad range of metabolites and elements in shoots and roots of different AtHKT1;1 genotypes and their parental strains before and after salinity stress,revealing a reciprocal relationship of metabolite differences between an AtHKT1;1 knockout line (hktl;1) and the AtHKT1;1 overexpressing lines (E2586 UASGAL4:HKT1;1 and J2731*UASGAL4:HKT1;1).Although levels of root sugars were increased after salt stress in both AtHKT1;1 overexpressing lines,E2586 UASGAL4:HKT1;1 showed higher accumulation of the osmoprotectants trehalose,gentiobiose,and melibiose,whereas J2731*UASGAL4:HKT1;1 showed higher levels of sucrose and raffinose,compared with their parental lines,respectively.In contrast,the knockout line hktl;1 showed strong increases in the levels of the tricarboxylic acid (TCA) cycle intermediates in the shoots after salt treatment.This coincided with a significant depletion of sugars,suggesting that there is an increased rate of carbon influx into the TCA cycle at a constant rate of C-efflux from the cycle,which might be needed to support plant survival during salt stress.Using correlation analysis,we identified associations between the Na+ content and several sugars,suggesting that regulation of sugar metabolism is important in plant responses to salinity stress.

  5. Asymmetric Ashes

    Science.gov (United States)

    2006-11-01

    that oscillate in certain directions. Reflection or scattering of light favours certain orientations of the electric and magnetic fields over others. This is why polarising sunglasses can filter out the glint of sunlight reflected off a pond. When light scatters through the expanding debris of a supernova, it retains information about the orientation of the scattering layers. If the supernova is spherically symmetric, all orientations will be present equally and will average out, so there will be no net polarisation. If, however, the gas shell is not round, a slight net polarisation will be imprinted on the light. This is what broad-band polarimetry can accomplish. If additional spectral information is available ('spectro-polarimetry'), one can determine whether the asymmetry is in the continuum light or in some spectral lines. In the case of the Type Ia supernovae, the astronomers found that the continuum polarisation is very small so that the overall shape of the explosion is crudely spherical. But the much larger polarization in strongly blue-shifted spectral lines evidences the presence, in the outer regions, of fast moving clumps with peculiar chemical composition. "Our study reveals that explosions of Type Ia supernovae are really three-dimensional phenomena," says Dietrich Baade. "The outer regions of the blast cloud is asymmetric, with different materials found in 'clumps', while the inner regions are smooth." "This study was possible because polarimetry could unfold its full strength thanks to the light-collecting power of the Very Large Telescope and the very precise calibration of the FORS instrument," he adds. The research team first spotted this asymmetry in 2003, as part of the same observational campaign (ESO PR 23/03 and ESO PR Photo 26/05). The new, more extensive results show that the degree of polarisation and, hence, the asphericity, correlates with the intrinsic brightness of the explosion. The brighter the supernova, the smoother, or less clumpy

  6. Lorentz Force on Sodium and Chlorine Ions in a Salt Water Solution Flow under a Transverse Magnetic Field

    Science.gov (United States)

    De Luca, R.

    2009-01-01

    It is shown that, by applying elementary concepts in electromagnetism and electrochemistry to a system consisting of salt water flowing in a thin rectangular pipe at an average velocity v[subscript A] under the influence of a transverse magnetic field B[subscript 0], an electromotive force generator can be conceived. In fact, the Lorentz force…

  7. The influence of salt type on the retention of bovine serum albumin in ion-exchange chromatography

    DEFF Research Database (Denmark)

    Al-Jibbouri, Sattar

    2007-01-01

    In this paper, an analysis of the influence of the salt types, NaCl, NaCH"3COO, Na"2SO"4 and Na"3C"6H"5O"7, on the isocratic retention behaviour of bovine serum albumin (BSA) on two anion-exchangers media (Source 30Q and TSK Gel Super Q 5 PW) has been presented. The retention data demonstrated...

  8. THz Spectroscopic Investigation of Energetic Ion Salt%含能离子盐的太赫兹光谱研究

    Institute of Scientific and Technical Information of China (English)

    黄平; 邱睿

    2012-01-01

    In order to further explore the terahertz spectrum characteristics of energetic ion salts on the basis of the research on traditional nitro energetic materials, and extend applicable scope of terahertz wave technology in the study of safety testing field, experimental measurement and theoretical analysis of THz spectrum for new energetic ion salts (5-ATN and BMDATHBT) were introduced. The absorption coefficient of the samples was measured in the region of 0. 5 ~ 2. 0 THz by time-domain spectroscopy and by Fourier transform infrared spectroscopy in the 2. 0~8. 0 THz region. Using the density functional theory methods, the vibration characteristics were simulated by Gaussian 03 and Materials Studio 4. 3. The simulated spectrum of samples is in agreement with the experimental data. The result showed that ion salts have the typical absorption peaks that have close relation with the tribal structure, and the interaction between particles and the single skeleton vibrations of individual ion are the main reason for energetic ion salt to form absorption peak in terahertz band, which provides references for detecting high nitrogen compounds by terahertz technique.%在传统硝基含能材料研究的基础上,进一步探索含能离子盐类物质的太赫兹波谱特性,拓宽太赫兹波技术在安全检测领域的应用研究范围,对新型含能离子盐(5-ATN,BMDATHBT)进行了太赫兹时域光谱和傅里叶变换红外光谱的实验测量,得到样品在0.5~8.0 THz范围内的吸收频谱.基于密度泛函理论,采用Gaussian 03及Materials Studio 4.3量子化学软件分别进行单分子与晶胞形式的模拟计算,结果与实验值较为一致.研究发现,含能离子盐5-ATN,BMDATHBT具有明显的特征吸收峰,这与此类物质的结构有密切关系,离子间的相互作用及单个离子的骨架振动是离子型化合物在太赫兹频段形成吸收峰的主要原因.研究为利用太赫兹波技术检测高氮离子型化合物提供了参考.

  9. Novel chiral N4S2- and N6S3-donor macrocyclic ligands: synthesis, protonation constants, metal-ion binding and asymmetric catalysis in the Henry reaction.

    Science.gov (United States)

    Gao, Jian; Martell, A E

    2003-08-01

    New hydrophobic chiral macrocyclic ligands L1-L3 with chiral diamino and thiophene moieties have been synthesized by the Schiff base condensation approach. Protonation constants of L1 and L2 were determined by potentiometry titration. Metal-ion binding experiments exhibited that L1 and L3 are pronounced in selective recognition, Ag+, Cu2+ and Ca2+ ions among the surveyed metal ions (Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+, Ag+, Li+, Na+, K+, and Ca2+). L1 was found to spectroscopically detect the presence of Cu2+ and Ca2+ to function as a multiple readout sensor. The detection limit for Ca2+ ions was found to be 9.8 x 10(-5) M in CH2Cl2-MeOH solution. The trimeric chiral ligand L3 has been shown to be an efficient auxiliary in a Zn(II)-mediated enantioselective Henry reaction. PMID:12948208

  10. In situ synthesis of ultra-fine, porous, tin oxide-carbon nanocomposites via a molten salt method for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bin [Institute of Applied Chemistry, Xinjiang University, Urumqi 830046 (China); School of Science, Xinjiang Eduction Institute, Urumqi, Xinjiang (China); Guo, Zai Ping [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); Institute of Applied Chemistry, Xinjiang University, Urumqi 830046 (China); School of Mechanical, Materials and Mechatronics Engineering, University of Wollongong, NSW 2522 (Australia); Du, Guodong; Hassan, Mohd Faiz [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); School of Mechanical, Materials and Mechatronics Engineering, University of Wollongong, NSW 2522 (Australia); Nuli, Yanna [Department of Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Mechanical, Materials and Mechatronics Engineering, University of Wollongong, NSW 2522 (Australia); Jia, Dianzeng [Institute of Applied Chemistry, Xinjiang University, Urumqi 830046 (China); School of Mechanical, Materials and Mechatronics Engineering, University of Wollongong, NSW 2522 (Australia)

    2010-08-15

    Ultra-fine, porous, tin oxide-carbon (SnO{sub 2}/C) nanocomposites are fabricated by a molten salt method at 300 C, and malic acid is decomposed as the carbon source. In situ synthesis is favourable for the combination of carbon and SnO{sub 2}. The structure and morphology are confirmed by X-ray diffraction analysis, specific surface-area measurements, and transmission electron microscopy (TEM). Examination of TEM images reveals that the SnO{sub 2} nanoparticles are embedded in the carbon matrix, with sizes between 2 and 5 nm. The electrochemical measurements show that the nanocomposite delivers a high capacity with good capacity retention as an anode material for lithium-ion batteries, due to the combination of the ultra-fine porous structure and the carbon component. (author)

  11. Electrodeposited tin coating as negative electrode material for lithium-ion battery in room temperature molten salt

    OpenAIRE

    Fung, YS; Zhu, DR

    2002-01-01

    A new room temperature molten salt (RTMS) [1-methyl-3-ethylimidazolium/AlCl3/SnCl2 (3:2:0.5)] was developed for depositing tin on a copper electrode. Different tin crystallites were deposited at different temperatures, giving widely different performances of the assembled lithium cell [Sn (Cu)/LiCl buffered MEICl-AlCl3 RTMS/lithium]. Tin film deposited at 50°C or higher gave a more desirable crystal structure and an improved performance than films obtained at lower temperatures. Both cyclic v...

  12. Temperature dependence of corrosion inhibition of steels used in oil well stimulation using acetylenic compound and halide ion salt mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, M.A.M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica], E-mail: marcom@eq.ufrj.br; Valle, M.L.M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica. Dept. de Processos Organicos; Dweck, J. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica. Dept. de Processos Inorganicos; Queiroz Neto, J.C. [Petroleo Brasileiro S.A. (CENPES / PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2007-07-15

    Halogenated salt (HS)-acetylenic compound (AC) mixtures were tested as corrosion inhibitors of 13Cr and 22Cr stainless steel and N80 and P110 carbon steel when exposed to 15 wt.% HCl solutions, at 50 deg C, 80 deg C and 100 deg C. The best corrosion inhibition efficiency is obtained when the concentration of both AC and HS is 1.5 wt. %, which indicates the use of all tested steels in oil well stimulation operated at 50 deg C and the use of 13Cr, N80 and P110 steels in oil well processing temperatures up to 100 deg C. (author)

  13. Principal Locations of Major-Ion, Trace-Element, Nitrate, and Escherichia coli Loading to Emigration Creek, Salt Lake County, Utah, October 2005

    Science.gov (United States)

    Kimball, Briant A.; Runkel, Robert L.; Walton-Day, Katherine

    2008-01-01

    Housing development and recreational activity in Emigration Canyon have increased substantially since 1980, perhaps causing an observed decrease in water quality of this northern Utah stream located near Salt Lake City. To identify reaches of the stream that contribute to water-quality degradation, a tracer-injection and synoptic-sampling study was done to quantify mass loading of major ions, trace elements, nitrate, and Escherichia coli (E. coli) to the stream. The resulting mass-loading profiles for major ions and trace elements indicate both geologic and anthropogenic inputs to the stream, principally from tributary and spring inflows to the stream at Brigham Fork, Burr Fork, Wagner Spring, Emigration Tunnel Spring, Blacksmith Hollow, and Killyon Canyon. The pattern of nitrate loading does not correspond to the major-ion and trace-element loading patterns. Nitrate levels in the stream did not exceed water-quality standards at the time of synoptic sampling. The majority of nitrate mass loading can be considered related to anthropogenic input, based on the field settings and trends in stable isotope ratios of nitrogen. The pattern of E. coli loading does not correspond to the major-ion, trace-element, or nitrate loading patterns. The majority of E. coli loading was related to anthropogenic sources based on field setting, but a considerable part of the loading also comes from possible animal sources in Killyon Canyon, in Perkins Flat, and in Rotary Park. In this late summer sampling, E. coli concentrations only exceeded water-quality standards in limited sections of the study reach. The mass-loading approach used in this study provides a means to design future studies and to evaluate the loading on a catchment scale.

  14. Hydronium-dominated ion transport in carbon-dioxide-saturated electrolytes at low salt concentrations in nanochannels

    DEFF Research Database (Denmark)

    Pennathur, Sumita; Kristensen, Jesper; Crumrine, Andrew;

    2011-01-01

    Nanochannel ion transport is known to be governed by surface charge at low ionic concentrations. In this talk, we show that this surface charge is dominated by hydronium ions arising from dissolution of ambient atmospheric carbon dioxide. By refining the electrokinetic model of the nanochannel...... the surface reaction equilibrium constant for silica/hydronium reactions. The model describes our experimental data with aqueous potassium chloride solutions in 165-nm-high silica nanochannels well, and furthermore, by comparing model predictions with measurements in bulk and in nanochannels with hydrochloric...

  15. Plausible molecular and crystal structures of chitosan/HI type II salt.

    Science.gov (United States)

    Lertworasirikul, Amornrat; Noguchi, Keiichi; Ogawa, Kozo; Okuyama, Kenji

    2004-03-15

    Chitosan/HI type II salt prepared from crab tendon was investigated by X-ray fiber diffraction. Two polymer chains and 16 iodide ions (I(-)) crystallized in a tetragonal unit cell with lattice parameters of a = b = 10.68(3), c (fiber axis) = 40.77(13) A, and a space group P4(1). Chitosan forms a fourfold helix with a 40.77 A fiber period having a disaccharide as the helical asymmetric unit. One of the O-3... O-5 intramolecular hydrogen bonds at the glycosidic linkage is weakened by interacting with iodide ions, which seems to cause the polymer to take the 4/1-helical symmetry rather than the extended 2/1-helix. The plausible orientations of two O-6 atoms in the helical asymmetric unit were found to be gt and gg. Two chains are running through at the corner and the center of the unit cell along the c-axis. They are linked by hydrogen bonds between N-21 and O-61 atoms. Two out of four independent iodide ions are packed between the corner chains while the other two are packed between the corner and center chains when viewing through the ab-plane. The crystal structure of the salt is stabilized by hydrogen bonds between these iodide ions and N-21, N-22, O-32, O-61, O-62 of the polymer chains.

  16. Effects of solvents and salt on the thermal stability of lithiated graphite used in lithium ion battery.

    Science.gov (United States)

    Wang, Qingsong; Sun, Jinhua; Chen, Chunhua

    2009-08-15

    The thermal stability of lithiated graphite in the presence of solvents, electrolytes and LiPF(6) salt was studied using C80 micro-calorimeter. The presence of cyclic carbonates or linear carbonates increases the activity of Li(x)C(6)-solvent coexisting system, especially for the Li(x)C(6)-linear carbonates one. LiPF(6) was detected that it increases the activity greatly of its coexisting system with lithiated graphite. The coexisting system of Li(x)C(6) with the electrolyte of LiPF(6)/ethylene carbonate+diethyl carbonate shows less thermal stability, which is attributed to the activity between diethyl carbonate and Li(x)C(6). This also agrees with the experiment result of Li(x)C(6)-diethyl carbonate coexisting system. PMID:19261386

  17. Extraction-Spectrophotometric Method for Determination of Gallium(III) in the Form of Ion Associate with a Monotetrazolium Salt

    Science.gov (United States)

    Stojnova, K. T.; Divarov, V. V.; Racheva, P. V.; Lekova, V. D.

    2015-11-01

    The possibility of application of the ternary ion-association complex of gallium(III), 4-(2-pyridyl azo)resorcinol (PAR) and 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) for extraction-spectrophotometric determination of gallium(III) was studied. The liquid-liquid extraction system Ga(III)-PAR-TTC-H2O-CHCl3 was applied for this purpose. The effect of the foreign ions on the extraction was investigated. Based on the obtained results, a sensitive, relatively simple, and inexpensive method for determination of gallium(III) in a model mixture was developed, which can be implemented in industrial, biological, medical, and pharmaceutical samples.

  18. Liquid-liquid extraction of ion-association complexes of cobalt(II-4-(2-pyridylazoresorcinol with ditetrazolium salts

    Directory of Open Access Journals (Sweden)

    Divarova Vidka V.

    2015-01-01

    Full Text Available The formation and liquid-liquid extraction of ion-association complexes between Co(II-4-(2-Pyridylazoresorcinol (PAR anionic chelates and cations of three ditetrazolium chlorides were studied: Blue Tetrazolium chloride (BTC, Neotetrazolium chloride (NTC and Nitro Blue Tetrazolium chloride (NBT. The optimum conditions for the formation and solvent extraction of the ion-association comlpex chelates were determined. It has been found that in the systems of Co(II-PAR-DTS, the reactants are reacted in molar ratios 1:2:1 and the general formula of complexes was suggested. The extraction equilibria were investigated and quantitatively characterized by the equilibrium constants and the recovery factors. The analytical characteristics of the complexes were calculated.

  19. Asymmetric Wettability Directs Leidenfrost Droplets

    Energy Technology Data Exchange (ETDEWEB)

    Agapov, Rebecca L [ORNL; Boreyko, Jonathan B [ORNL; Briggs, Dayrl P [ORNL; Srijanto, Bernadeta R [ORNL; Retterer, Scott T [ORNL; Collier, Pat [ORNL; Lavrik, Nickolay V [ORNL

    2014-01-01

    Leidenfrost phenomena on nano- and microstructured surfaces are of great importance for increasing control over heat transfer in high power density systems utilizing boiling phenomena. They also provide an elegant means to direct droplet motion in a variety of recently emerging fluidic systems. Here, we report the fabrication and characterization of tilted nanopillar arrays (TNPAs) that exhibit directional Leidenfrost water droplets under dynamic conditions, namely on impact with Weber numbers 40 at T 325 C. The batch fabrication of the TNPAs was achieved by glancing-angle anisotropic reactive ion etching of a thermally dewet platinum mask, with mean pillar diameters of 100 nm and heights of 200-500 nm. In contrast to previously implemented macro- and microscopic Leidenfrost ratchets, our TNPAs induce no preferential directional movement of Leidenfrost droplets under conditions approaching steady-state film boiling, suggesting that the observed droplet directionality is not a result of asymmetric vapor flow. Using high-speed imaging, phase diagrams were constructed for the boiling behavior upon impact for droplets falling onto TNPAs, straight nanopillar arrays, and smooth silicon surfaces. The asymmetric impact and directional trajectory of droplets was exclusive to the TNPAs for impacts corresponding to the transition boiling regime, revealing that asymmetric wettability upon impact is the mechanism for the droplet directionality.

  20. Salt Tolerance in Soybean

    Institute of Scientific and Technical Information of China (English)

    Tsui-Hung Phang; Guihua Shao; Hon-Ming Lam

    2008-01-01

    Soybean is an Important cash crop and its productivity is significantly hampered by salt stress. High salt Imposes negative impacts on growth, nodulation, agronomy traits, seed quality and quantity, and thus reduces the yield of soybean. To cope with salt stress, soybean has developed several tolerance mechanisms, including: (I) maintenance of ion homeostasis; (ii) adjustment in response to osmotic stress; (iii) restoration of osmotic balance; and (iv) other metabolic and structural adaptations. The regulatory network for abiotic stress responses in higher plants has been studied extensively in model plants such as Arabidopsis thaliana. Some homologous components involved in salt stress responses have been identified in soybean. In this review, we tried to integrate the relevant works on soybean and proposes a working model to descdbe Its salt stress responses at the molecular level.

  1. Electrochemical characteristics of Li 2- xVTiO 4 rock salt phase in Li-ion batteries

    Science.gov (United States)

    Dominko, R.; Garrido, C. Vidal-Abraca; Bele, M.; Kuezma, M.; Arcon, I.; Gaberscek, M.

    Li 2- xVTiO 4/C sample with a disordered rock salt structure was successfully prepared by annealing at a temperature of 850 °C. The electrochemical oxidation in the first cycle occurs at voltages above 4 V vs. metallic lithium, while the shapes of the electrochemical curves in consequent reduction-oxidation processes show a monotonous change of the potential between the selected cut-off voltages. A linear combination fit of individual XANES spectra was used for the determination of the oxidation states of as prepared sample and intermediate states during oxidation and reduction. In the as-prepared sample, vanadium was found to be in the average oxidation state of V 3.5+ and was additionally oxidized to V 3.8+ by the electrochemical charging. During the discharge process, the vanadium oxidation state was reduced to V 3.0+. In situ X-ray diffraction patterns and EXAFS analysis suggest good structural stability during oxidation and reduction, which is also reflected in the cycling stability if batteries were cycled in the voltage window between 2.0 V and 4.4 V. Extension of the lower cut-off voltage to 1.0 V doubles the capacity retention with the improved capacity stability if compared with several high capacity vanadium based materials.

  2. Physiological mechanisms for high salt tolerance in wild soybean (Glycine soja) from Yellow River Delta, China: photosynthesis, osmotic regulation, ion flux and antioxidant capacity.

    Science.gov (United States)

    Chen, Peng; Yan, Kun; Shao, Hongbo; Zhao, Shijie

    2013-01-01

    Glycine soja (BB52) is a wild soybean cultivar grown in coastal saline land in Yellow River Delta, China. In order to reveal the physiological mechanisms adapting to salinity, we examined photosynthesis, ion flux, antioxidant system and water status in Glycine soja under NaCl treatments, taking a cultivated soybean, ZH13, as control. Upon NaCl exposure, higher relative water content and water potential were maintained in the leaf of BB52 than ZH13, which might depend on the more accumulation of osmotic substances such as glycinebetaine and proline. Compared with ZH13, activities of antioxidant enzymes including superoxide dismutase, catalase, ascorbate peroxidase and contents of ascorbate, glutathione and phenolics were enhanced to a higher level in BB52 leaf under NaCl stress, which could mitigate the salt-induced oxidative damage in BB52. Consistently, lipid peroxidation indicated by malondialdehyde content was lower in BB52 leaf. Photosynthetic rate (Pn) was decreased by NaCl stress in BB52 and ZH13, and the decrease was greater in ZH13. The decreased Pn in BB52 was mainly due to stomatal limitation. The inhibited activation of rubisco enzyme in ZH13 due to the decrease of rubisco activase content became an important limiting factor of Pn, when NaCl concentration increased to 200 mM. Rubisco activase in BB52 was not affected by NaCl stress. Less negative impact in BB52 derived from lower contents of Na(+) and Cl(-) in the tissues, and non-invasive micro-test technique revealed that BB52 roots had higher ability to extrude Na(+) and Cl(-). Wild soybean is a valuable genetic resource, and our study may provide a reference for molecular biologist to improve the salt tolerance of cultivated soybean in face of farmland salinity.

  3. Hydration and ion pair formation in common aqueous La(III) salt solutions--a Raman scattering and DFT study.

    Science.gov (United States)

    Rudolph, Wolfram W; Irmer, Gert

    2015-01-01

    Raman spectra of aqueous lanthanum perchlorate, triflate (trifluorosulfonate), chloride and nitrate solutions were measured over a broad concentration (0.121-3.050 mol L(-1)) range at room temperature (23 °C). A very weak mode at 343 cm(-1) with a full width at half height at 49 cm(-1) in the isotropic spectrum suggests that the nona-aqua La(III) ion is thermodynamically stable in dilute perchlorate solutions (∼0.2 mol L(-1)) while in concentrated perchlorate solutions outer-sphere ion pairs and contact ion pairs are formed. The La(3+) nona-hydrate was also detected in a 1.2 mol L(-1) La(CF3SO3)3(aq). In lanthanum chloride solutions chloro-complex formation was detected over the measured concentration range from 0.5-3.050 mol L(-1). The chloro-complexes in LaCl3(aq) are fairly weak and disappear with dilution. At a concentration complexes disappeared. In LaCl3 solutions, with additional HCl, a series of chloro-complexes of the type [La(OH2)(9-n)Cln](+3-n) (n = 1-3) were formed. The La(NO3)3(aq) spectra were compared with a spectrum of a 0.409 mol L(-1) NaNO3(aq) and it was concluded that in La(NO3)3(aq) over the concentration range from 0.121-1.844 mol L(-1), nitrato-complexes, [La(OH2)(9-n)(NO3)n](+3-n) (n = 1, 2) were formed. These nitrato-complexes are quite weak and disappear with dilution La(OH2)9](3+) with the polarizable dielectric continuum are in good agreement with data from recent structural experimental measurements and high quality simulations. The DFT frequency of the La-O stretching mode at 328.2 cm(-1), is only slightly smaller than the experimental one.

  4. Determination of the electrochemical performance and stability of the lithium-salt, lithium 4,5-dicyano-2-(trifluoromethyl) imidazolide, with various anodes in Li-ion cells

    Science.gov (United States)

    Paillet, Sabrina; Schmidt, Gregory; Ladouceur, Sébastien; Fréchette, Joël; Barray, Francis; Clément, Daniel; Hovington, Pierre; Guerfi, Abdelbast; Vijh, Ashok; Cayrefourcq, Ian; Zaghib, Karim

    2015-12-01

    The electrochemical performance and stability of lithium 4,5-dicyano-2-(trifluoromethyl) imidazolide (LiTDI), which is a promising lithium salt for electrolytes in lithium-ion batteries, are discussed. The power capability of LiTDI in EC/DEC (3/7 v/v) in half cells was evaluated with standard anodes used in the lithium-ion battery industry: graphite and Li4Ti5O12 (LTO). The effects of two additives, vinylene carbonate (VC) and fluoro-ethylene carbonate (FEC), were investigated (2% weight in EC/DEC) and compared with a reference electrolyte, 1 M LiPF6 (EC/DEC + 2%VC). LiTDI forms a thin SEI with FEC that is uniformly deposited on graphite, which allows high power capability with 93.9% of the specific capacity at 10C (92.3% for 1 M LiPF6 + 2%VC). Excellent results were also obtained for LiTDI with LTO, 91.1% of the specific capacity was recovered at 10C vs. 91.5% for LiPF6. The stability of LiTDI was evaluated in pouch-cells: LFP/LTO (1C-rate) and NMC/LTO (C/4-rate). The results show that the performance of LiTDI is comparable to that of LiPF6, 85.4% of the capacity was recovered after 900 cycles (87.6% for LiPF6) for LFP/LTO, and 85.8% of capacity was obtained after 450 cycles (86.3% for LiPF6) for NMC/LTO.

  5. Anion- interactions in layered structures of salts of 5-(hydroxyimino) quinolin-8-one and related salts

    Indian Academy of Sciences (India)

    Prithiviraj Khakhlary; Jubaraj B Baruah

    2015-01-01

    Relevance of anion- interactions in chloride, bromide, nitrate and perchlorate salts of 5-(hydroxyimino)quinolin-8-one are discussed. Structures of nitrate salt of 5-aminoquinoline as well as nitrate salt of 4-hydroxyquinazoline are compared with the structure of nitrate salt of 5-(hydroxyimino)quinolin-8-one. From such a comparison, two different arrangements of nitrate ions with respect to the respective cations are discerned. Nitrate ions are sandwiched between aromatic planes of cations in nitrate salts of 5-(hydroxyimino)quinolin-8-one or 4-hydroxyquinazoline; whereas, nitrate ions are in oblique positions with respect to aromatic planes of counter cations in nitrate salt of 5-aminoquinoline. Binding constants of different nitrate salts in solution are determined by UV-visible spectroscopic titrations. Solution study shows formation of ion-pairs of these salts in solution.

  6. Synthesis, Characterization and Properties of Asymmetric Methide Anion Based Ionic Liquids Containing Nitrile Groups

    Institute of Scientific and Technical Information of China (English)

    ZOU Ting; LU Liang; LIU Xiu-Li; ZHANG Zhan; WANG Li-Bing; FU Xian-Lei; GAO Guo-Hua; KOU Yuan; HE Ming-Yuan

    2008-01-01

    A series of asymmetric methide anion based ionic liquids containing nitrile groups have been synthesized for the first time using the method of ion-exchange between sodium/potassium methide and various quaternary bro-mide/chloride salts of trimethylamine, triethylamine, tributylamine, N-methylpyrrolidine, and N-methylimidazole. All of the functionalised ionic liquids were characterized by IR, 1H, 13C NMR, MS and elemental analysis. The de-composition temperature of the ionic liquids measured via TGA ranged from 219 to 339 ℃. The functionalised ionic liquid, [Bmim][C(CN)2COCH3], was used as a ligand for Suzuki coupling reaction. The yields of the coupling reaction increased 10%-15% by the addition of the functionalised ionic liquid, [Bmim] [C(CN)2COCH3].

  7. Hydrogen sulfide is involved in maintaining ion homeostasis via regulating plasma membrane Na+/H+ antiporter system in the hydrogen peroxide-dependent manner in salt-stress Arabidopsis thaliana root.

    Science.gov (United States)

    Li, Jisheng; Jia, Honglei; Wang, Jue; Cao, Qianhua; Wen, Zichao

    2014-07-01

    Hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) function as the signaling molecules in plants responding to salt stresses. The present study presents a signaling network involving H2S and H2O2 in salt resistance pathway of the Arabidopsis root. Arabidopsis roots were sensitive to 100 mM NaCl treatment, which displayed a great increase in electrolyte leakage (EL) and Na(+)/K(+) ratio under salt stress. The treatment of H2S donors sodium hydrosulfide (NaHS) enhanced the salt tolerance by maintaining a lower Na(+)/K(+) ratio. In addition, the inhibition of root growth under salt stress was removed by H2S. Further studies indicated that H2O2 was involved in H2S-induced salt tolerance pathway. H2S induced the production of the endogenous H2O2 via regulating the activities of glucose-6-phosphate dehydrogenase (G6PDH) and plasma membrane (PM) NADPH oxidase, with the treatment with dimethylthiourea (DMTU, an ROS scavenger), diphenylene iodonium (DPI, a PM NADPH oxidase inhibitor), or glycerol (G6PDH inhibitor) removing the effect of H2S. Treatment with amiloride (an inhibitor of PM Na(+)/H(+) antiporter) and vanadate (an inhibitor of PM H(+)-ATPase) also inhibited the activity of H2S on Na(+)/K(+) ratio. Through an analysis of quantitative real-time polymerase chain reaction and Western blot, we found that H2S promoted the genes expression and the phosphorylation level of PM H(+)-ATPase and Na(+)/H(+) antiporter protein level. However, when the endogenous H2O2 level was inhibited by DPI or DMTU, the effect of H2S on the PM Na(+)/H(+) antiporter system was removed. Taken together, H2S maintains ion homeostasis in the H2O2-dependent manner in salt-stress Arabidopsis root.

  8. Asymmetric Wettability Directs Leidenfrost Droplets

    Science.gov (United States)

    Agapov, Rebecca; Boreyko, Jonathan; Briggs, Dayrl; Srijanto, Bernadeta; Retterer, Scott; Collier, C. Patrick; Lavrik, Nickolay

    2014-03-01

    Exploration of Leidenfrost droplets on nano- and microstructured surfaces are of great importance for increasing control over heat transfer in high power density systems using boiling phenomena. They also provide an elegant way to direct droplet motion in a variety of emerging fluidic systems. Here, we report the fabrication and characterization of tilted nanopillar arrays (TNPAs) that exhibit directional Leidenfrost water droplets under dynamic conditions. The batch fabrication of the TNPAs was achieved by glancing-angle anisotropic reactive ion etching of a thermally dewet platinum mask. In contrast to previously implemented macro- and microscopic Leidenfrost ratchets, our TNPAs induce no preferential directional movement of Leidenfrost droplets under conditions approaching steady-state film boiling. This suggests that the observed droplet directionality is not a result of asymmetric vapor flow. Phase diagrams were constructed for the boiling behavior upon droplet impact onto TNPAs, straight nanopillar arrays, and smooth silicon surfaces. Asymmetric wettability and directional trajectory of droplets was exclusive to the TNPAs for impacts corresponding to the transition boiling regime, revealing this to be the mechanism for the droplet directionality. This work was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Lab by the Division of Scientific User Facilities, US Dept. of Energy.

  9. 土壤盐胁迫降低后甜高粱的补偿生长和盐离子分布特征%The compensation growth and salt ion distribution in sweet sorghum (Sorghum bicolor L. Moench) after salt stress reduction

    Institute of Scientific and Technical Information of China (English)

    李春宏; 郭文琦; 张培通; 殷剑美; 韩晓勇; 王立

    2016-01-01

    Adversity compensation effect is ubiquity in crops, which impacts on crop growth, development and yield. To elucidate the compensation growth of sweet sorghum following soil salt stress reduction, a pot experiment was conducted, in which 5 g×kg-1 (high salt), 2 g×kg-1 down from 5 g×kg-1 (salt stress reduction) and 2 g×kg-1 (low-salt control) of soil salt treatments were applied at the elongation stage of sweet sorghum. Then growth rate of dry matter on aboveground parts (leaf, leaf sheath and stem) and aboveground dry matter at maturity of two cultivated sweet sorghum varieties were determined. The experiment also measured salt ions (K+, Na+ and Cl-) distribution in aboveground organs of sweet sorghum. The results showed that the growth rate of aboveground dry matter in high salt treatment was always significantly lower than that of control. There was clear acceleration of growth after soil salt reduction, and gradually exceeded the growth of control due to overcompensation effect. At maturity stage, both plant height and aboveground dry matter of two sorghum varieties decreased sharply in high salt treatment. They decreased by 7.69% and 33.21%, respectively, in ‘Liaotian 1’ in salt stress reduction treatment compared with the low-salt control, moreover, no obviously difference was found in both plant height and aboveground dry matter of ‘Zhongketian 3’ between salt stress reduction treatment and low-salt control. The contents of Na+and Cl-in aboveground organs significantly increased, and K+content slightly increased under high salt stressed condition. At 35 days after soil salt reduction, the contents of Na+ and Cl- still higher than that of low-salt control, but decreased significantly compared to that of high salt treatment. Although K+content in both leaf sheath and stem in soil salt reduction treatment were higher than that of low-salt control, no difference was observed in leaf. The results suggested that ion toxicity in salt-stressed sweet

  10. Modeling on sensitivity of soil salt ions to electrical conductivity of soil extract%土壤盐分离子对浸提液电导率的敏感性分析建模

    Institute of Scientific and Technical Information of China (English)

    马亮; 何继武; 刘锋; 陈亮亮

    2011-01-01

    A study was conducted on the sensitivity of soil salt ions to the electrical conductivity of soil extract to promote technical progress in improved alkaline field and salt-water movement theory in depth. A preliminary qualitative analysis was first made by applying grey relational analysis in electrical conductivity of soil extract and salt ions, and then by default factor analysis and principal component analysis for further authentication. The results show that: Cl ~ and Na+ ions are mors sensitive than any other ions to the electrical conductivity of soil extract; the results of gray relational analysis method are the same as the results of principal component analysis model based on the default factor method; the seven salt ions have multicollinearity on electrical conductivity of soil extract, and the conductivity prediction model based on principal component regression method can make reasonable simulation of variables. This provides a new way for further study on salt - water movement theory.%为了研究土壤盐分离子对浸提液电导率的敏感性,首先采用灰色关联分析法对影响土壤浸提液电导率的盐分离子进行初步分析,之后采用缺省因子法与主成分分析法进一步分析检验.结果表明:Cl-、Na+这两种离子对土壤浸提液电导率的变化最为敏感;灰色关联分析法所得结果与基于缺省因子法的主成分分析模型结果基本一致;影响土壤浸提液电导率的7种盐分离子之间存在多重共线性,应用主成分回归方法建立的电导率预测模型能够对实测变量作出合理的模拟.

  11. Novel binary deep eutectic electrolytes for rechargeable Li-ion batteries based on mixtures of alkyl sulfonamides and lithium perfluoroalkylsulfonimide salts

    Science.gov (United States)

    Geiculescu, O. E.; DesMarteau, D. D.; Creager, S. E.; Haik, O.; Hirshberg, D.; Shilina, Y.; Zinigrad, E.; Levi, M. D.; Aurbach, D.; Halalay, I. C.

    2016-03-01

    Ionic liquids (IL's) were proposed for use in Li-ion batteries (LIBs), in order to mitigate some of the well-known drawbacks of LiPF6/mixed organic carbonates solutions. However, their large cations seriously decrease lithium transference numbers and block lithium insertion sites at electrode-electrolyte interfaces, leading to poor LIB rate performance. Deep eutectic electrolytes (DEEs) (which share some of the advantages of ILs but possess only one cation, Li+), were then proposed, in order to overcome the difficulties associated with ILs. We report herein on the preparation, thermal properties (melting, crystallization, and glass transition temperatures), transport properties (specific conductivity and viscosity) and thermal stability of binary DEEs based on mixtures of lithium bis(trifluoromethane)sulfonimide or lithium bis(fluoro)sulfonimide salts with an alkyl sulfonamide solvent. Promise for LIB applications is demonstrated by chronoamperometry on Al current collectors, and cycling behavior of negative and positive electrodes. Residual current densities of 12 and 45 nA cm-2 were observed at 5 V vs. Li/Li+ on aluminum, 1.5 and 16 nA cm-2 at 4.5 V vs. Li/Li+, respectively for LiFSI and LiTFSI based DEEs. Capacities of 220, 130, and 175 mAh· g-1 were observed at low (C/13 or C/10) rates, respectively for petroleum coke, LiMn1/3Ni1/3Co1/3O2 (a.k.a. NMC 111) and LiAl0.05Co0.15Ni0.8O2 (a.k.a. NCA).

  12. A Semi-Analytical Line Transfer (SALT) model to interpret the spectra of galaxy outflows

    CERN Document Server

    Scarlata, C

    2015-01-01

    We present a Semi-Analytical Line Transfer model, SALT, to study the absorption and re-emission line profiles from expanding galactic envelopes. The envelopes are described as a superposition of shells with density and velocity varying with the distance from the center. We adopt the Sobolev approximation to describe the interaction between the photons escaping from each shell and the remaining of the envelope. We include the effect of multiple scatterings within each shell, properly accounting for the atomic structure of the scattering ions. We also account for the effect of a finite circular aperture on actual observations. For equal geometries and density distributions, our models reproduce the main features of the profiles generated with more complicated transfer codes. Also, our SALT line profiles nicely reproduce the typical asymmetric resonant absorption line profiles observed in star-forming/starburst galaxies whereas these absorption profiles cannot be reproduced with thin shells moving at a fixed out...

  13. Crystal structures of five 1-alkyl-4-aryl-1,2,4-triazol-1-ium halide salts

    Directory of Open Access Journals (Sweden)

    Marites A. Guino-o

    2015-06-01

    Full Text Available The asymmetric units for the salts 4-(4-fluorophenyl-1-isopropyl-1,2,4-triazol-1-ium iodide, C11H13FN3+·I−, (1, 1-isopropyl-4-(4-methylphenyl-1,2,4-triazol-1-ium iodide, C12H16N3+·I−, (2, 1-isopropyl-4-phenyl-1,2,4-triazol-1-ium iodide, C11H14N3+·I−, (3, and 1-methyl-4-phenyl-1,2,4-triazol-1-ium iodide, C9H10N3+·I−, (4, contain one cation and one iodide ion, whereas in 1-benzyl-4-phenyl-1,2,4-triazol-1-ium bromide monohydrate, C15H14N3+·Br−·H2O, (5, there is an additional single water molecule. There is a predominant C—H...X(halide interaction for all salts, resulting in a two-dimensional extended sheet network between the triazolium cation and the halide ions. For salts with para-substitution on the aryl ring, there is an additional π–anion interaction between a triazolium carbon and iodide displayed by the layers. For salts without the para-substitution on the aryl ring, the π–π interactions are between the triazolium and aryl rings. The melting points of these salts agree with the predicted substituent inductive effects.

  14. Sessile multidroplets and salt droplets under high tangential electric fields

    Science.gov (United States)

    Xie, Guoxin; He, Feng; Liu, Xiang; Si, Lina; Guo, Dan

    2016-01-01

    Understanding the interaction behaviors between sessile droplets under imposed high voltages is very important in many practical situations, e.g., microfluidic devices and the degradation/aging problems of outdoor high-power applications. In the present work, the droplet coalescence, the discharge activity and the surface thermal distribution response between sessile multidroplets and chloride salt droplets under high tangential electric fields have been investigated with infrared thermography, high-speed photography and pulse current measurement. Obvious polarity effects on the discharge path direction and the temperature change in the droplets in the initial stage after discharge initiation were observed due to the anodic dissolution of metal ions from the electrode. In the case of sessile aligned multidroplets, the discharge path direction could affect the location of initial droplet coalescence. The smaller unmerged droplet would be drained into the merged large droplet as a result from the pressure difference inside the droplets rather than the asymmetric temperature change due to discharge. The discharge inception voltages and the temperature variations for two salt droplets closely correlated with the ionization degree of the salt, as well as the interfacial electrochemical reactions near the electrodes. Mechanisms of these observed phenomena were discussed. PMID:27121926

  15. Ion Colliders

    CERN Document Server

    Fischer, W

    2014-01-01

    High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

  16. Removal and separation of impurity ions in preparation of high-purity inorganic salts%高纯无机盐制备中杂质离子的去除与分离

    Institute of Scientific and Technical Information of China (English)

    石磊

    2012-01-01

    介绍了在制备高纯无机盐过程中,有害杂质离子——重有色金属离子(Cu、Mg、Zn、Pd、Cd等)、铁离子、砷化物的去除与分离方法:氧化-还原法、难溶金属氢氧化物沉淀法、硫化物沉淀法.%Introduced in the preparation of high purity inorganic salt process, harmful impurity ion-heavy non-ferrous metal ion (Cu,Mg,Zn,Pd,CDS,etc. ) ,iron ion,arsenide in removing and separation methods : oxidation-reduction method and difficult to thick metal hydroxide precipitation, sulfide precipitation.

  17. Thomson scattering measurements from asymmetric interpenetrating plasma flows

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J. S., E-mail: ross36@llnl.gov; Moody, J. D.; Fiuza, F.; Ryutov, D.; Divol, L.; Huntington, C. M.; Park, H.-S. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

    2014-11-15

    Imaging Thomson scattering measurements of collective ion-acoustic fluctuations have been utilized to determine ion temperature and density from laser produced counter-streaming asymmetric flows. Two foils are heated with 8 laser beams each, 500 J per beam, at the Omega Laser facility. Measurements are made 4 mm from the foil surface using a 60 J 2ω probe laser with a 200 ps pulse length. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the multi-ion species, asymmetric flows theoretical form factor for the ion feature such that the ion temperatures, ion densities, and flow velocities for each plasma flow are determined.

  18. Synthesis and characterization of a new family of aryl-trifluoromethanesulfonylimide Li-Salts for Li-ion batteries and beyond

    Science.gov (United States)

    Ladouceur, Sébastien; Paillet, Sabrina; Vijh, Ashok; Guerfi, Abdelbast; Dontigny, Martin; Zaghib, Karim

    2015-10-01

    The battery energy-storage industry is evolving rapidly so new battery components are needed with high stability and improved energy density, as well as enhanced safety. In this paper, results on new salts, safer degradation and good electrochemical performances are reported. Four organic anions for Li-salts were synthesized and their conductivity, viscosity and electrochemical potential window in EC/DEC (3/7) solutions were examined. These salts have high thermal stability and safer degradation products (compared to LiPF6 and Li-TFSI), which were identified by TGA-MS. Cyclic voltammetry measurements showed their electrochemical window and oxidation limits were at least 4.3 and 4.5 V vs Li/Li+ using a platinum and high surface area carbon material working electrode, respectively. The salts passivated the common aluminum current collector at 4.4 V vs Li/Li+ and without corrosion. The properties of one Li salts were evaluated in half cell configuration as a model system using lithium iron phosphate (LFP), lithium titanate oxide (LTO) and graphite as electrodes. The performance of the salt showed promising behavior in the model system, compared to benchmark salts such as LiPF6 and Li-TFSI.

  19. Asymmetrical international attitudes

    NARCIS (Netherlands)

    Van Oudenhoven, JP; Askevis-Leherpeux, F; Hannover, B; Jaarsma, R; Dardenne, B

    2002-01-01

    In general, attitudes towards nations have a fair amount of reciprocity: nations either like each other are relatively indifferent to each other or dislike each other Sometimes, however international attitudes are asymmetrical. In this study, we use social identity theory in order to explain asymmet

  20. An asymmetric Kadison's inequality

    CERN Document Server

    Bourin, Jean-Christophe

    2010-01-01

    Some inequalities for positive linear maps on matrix algebras are given, especially asymmetric extensions of Kadison's inequality and several operator versions of Chebyshev's inequality. We also discuss well-known results around the matrix geometric mean and connect it with complex interpolation.

  1. Asymmetric reactions in continuous flow

    Directory of Open Access Journals (Sweden)

    Xiao Yin Mak

    2009-04-01

    Full Text Available An overview of asymmetric synthesis in continuous flow and microreactors is presented in this review. Applications of homogeneous and heterogeneous asymmetric catalysis as well as biocatalysis in flow are discussed.

  2. Asymmetric catalysis with helical polymers

    NARCIS (Netherlands)

    Megens, Rik P.; Roelfes, Gerard

    2011-01-01

    Inspired by nature, the use of helical biopolymer catalysts has emerged over the last years as a new approach to asymmetric catalysis. In this Concept article the various approaches and designs and their application in asymmetric catalysis will be discussed.

  3. Determination of Hazardous Chemicals by Microchip-based Field Asymmetric Waveform Ion Mobility Spectrometric Technology%芯片级高场非对称波形离子迁移谱技术检测危险品

    Institute of Scientific and Technical Information of China (English)

    张洁; 李灵锋; 郭大鹏; 张媛; 王琦; 李鹏; 汪小知

    2013-01-01

    An in-situ analytical procedure employing silicon chip based ultra high field asymmetric waveform ion mobility spectrometry(FAIMS) via direct sniffing was developed.The sample introduction temperature was 50 ℃.The carrier gas flow rate and the sample flow rate were 1500 mL/min and 100 mL/min respectively.Ten listed hazardous chemicals,which were prohibited for public transportation in China,were selected to verify the procedure in terms of validity,sensitivity and selectivity.Recognition algorithm was also developed for the FAIMS fingerprint spectral.Ten chemicals were resolved with high reproducibility at the concentration from 0.1 to 20 mg/L.In comparison with current competing instruments,the microchip-based FAIMS instrument,which features its simplicity,high sensitivity and selectivity,fast response and free of sample pretreatment,opens up new applications in the field of public security and homeland security.%建立了吸气法-芯片级高场非对称波形离子迁移谱(FAIMS)技术,设置进样温度为50℃,载气与样品气流量分别为1500和100 mL/min时,测定了10种国家交通部门规定严禁携带的易燃易爆危险品.实验结果表明,利用FAIMS技术可以有效检测多种危险品.实验得到了10种危险品的FAIMS图谱,并对其进行了指纹识别.利用扩散管辅助技术得到10种物质的检测浓度范围约为0.1 ~20 mg/L.此方法方便快速,灵敏度高,具有很好的应用前景.

  4. Asymmetric information and economics

    Science.gov (United States)

    Frieden, B. Roy; Hawkins, Raymond J.

    2010-01-01

    We present an expression of the economic concept of asymmetric information with which it is possible to derive the dynamical laws of an economy. To illustrate the utility of this approach we show how the assumption of optimal information flow leads to a general class of investment strategies including the well-known Q theory of Tobin. Novel consequences of this formalism include a natural definition of market efficiency and an uncertainty principle relating capital stock and investment flow.

  5. Asymmetric Organocatalytic Cycloadditions

    DEFF Research Database (Denmark)

    Mose, Rasmus

    2016-01-01

    were pioneered by Otto Paul Hermann Diels and Kurt Alder who discovered what later became known as the Diels Alder reaction. The Diels Alder reaction is a [4+2] cycloaddition in which a π4 component reacts with a π2 component via a cyclic transition state to generate a 6 membered ring. This reaction...... reactions constitute the first organocatalytic asymmetric higher order cycloadditions and a rational for the periselectivity and stereoselectivity is provided based on experimental and computational investigations....

  6. 含咪唑环不对称双季铵盐的合成及缓蚀性能研究%synthesis and corrosion inhibition performance of the asymmetric bis Quaternary ammonium salt containinG imidaZole rinG

    Institute of Scientific and Technical Information of China (English)

    余宗学; 梁灵; 何毅; 马瑜; 李飞; 陈映晓

    2014-01-01

    成功合成了含咪唑环不对称双季铵盐,通过失重法、电化学阻抗谱、动电位扫描极化曲线、扫描电镜对合成产物在3% NaCl的饱和二氧化碳溶液中的缓蚀效率进行研究。结果表明,其在饱和二氧化碳溶液中对钢铁有着良好的缓蚀作用,缓蚀效率接近90%;运用Langmuir吸附等温式对吸附行为进行了拟合,表明其吸附类型符合Lang-muir吸附模型,吸附方式为化学吸附。%The asymmetric bis quaternary ammonium salt containing imidazole ring was synthesised suc-cessfully. And weight-loss method,electrochemical impedance spectroscopy,potentiodynamic polarization curve,scanning electron microscopy was used to study on the inhibition efficiency of this product in sodi-um chloride solutions(3. 00%)bubbled with CO2-saturated. The result shows that it has good corrosion inhibition for the P110 steel in this solution,and the corrosion inhibition efficiency is closed to 90%. The adsorption behavior was fitted using the Langmuir adsorption isotherm,and showed that the adsorption type conforms to the Langmuir adsorption isotherm,its adsorption mode is chemical adsorption.

  7. Probing the effect of different cross-sections in asymmetric collisions

    OpenAIRE

    Kaur, Deepinder; Kaur, Varinderjit; Kumar, Suneel

    2011-01-01

    We present a complete systematic theoretical study of multifragmentation for asymmetric colliding nuclei for heavy-ion reactions in the energy range between 50 MeV/nucleon and 1000 MeV/nucleon by using isospin dependent quantum molecular dynamics (IQMD) model. We have observed an interesting outcome for asymmetric colliding nuclei. The comparison between the symmetric and asymmetric colliding nuclei for the isospin independent cross section and isospin dependent cross section has been studied...

  8. Origin of Asymmetric Charge Partitioning in the Dissociation of Gas-Phase Protein Homodimers

    OpenAIRE

    Jurchen, John C.; Evan R Williams

    2003-01-01

    The origin of asymmetric charge and mass partitioning observed for gas-phase dissociation of multiply charged macromolecular complexes has been hotly debated. These experiments hold the potential to provide detailed information about the interactions between the macromolecules within the complex. Here, this unusual phenomenon of asymmetric charge partitioning is investigated for several protein homodimers. Asymmetric charge partitioning in these ions depends on a number of factors, including ...

  9. FT-IR and FT-Raman studies of cross-linking processes with Ca2+ ions, glutaraldehyde and microwave radiation for polymer composition of poly(acrylic acid)/sodium salt of carboxymethyl starch - Part I

    Science.gov (United States)

    Grabowska, Beata; Sitarz, Maciej; Olejnik, Ewa; Kaczmarska, Karolina

    2015-01-01

    FT-IR and FT-Raman spectroscopic methods allowed to identify the cross-linking process of the aqueous composition of poly(acrylic acid)/sodium salt of carboxymethyl starch (PAA/CMS-Na) applied as a binder for moulding sands. The cross-linking was performed by chemical methods by introducing cross-linking substances with Ca2+ ions or glutaraldehyde and by physical way, applying the microwave radiation. It was found that Ca2+ ions cause formation of cross-linking ionic bonds within carboxyl and carboxylate groups. Glutaraldehyde generates formation of cross-linking bonds with hemiacetal and acetal structures. Whereas in the microwave radiation field, due to dehydration, lattices are formed by anhydride bonds.

  10. Salt splitting with ceramic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kurath, D. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    The purpose of this task is to develop ceramic membrane technologies for salt splitting of radioactively contaminated sodium salt solutions. This technology has the potential to reduce the low-level waste (LLW) disposal volume, the pH and sodium hydroxide content for subsequent processing steps, the sodium content of interstitial liquid in high-level waste (HLW) sludges, and provide sodium hydroxide free of aluminum for recycle within processing plants at the DOE complex. Potential deployment sites include Hanford, Savannah River, and Idaho National Engineering Laboratory (INEL). The technical approach consists of electrochemical separation of sodium ions from the salt solution using sodium (Na) Super Ion Conductors (NaSICON). As the name implies, sodium ions are transported rapidly through these ceramic crystals even at room temperatures.

  11. Electronic structure and electro-optical properties of ion radicals formed during the reduction of N, N'-dialkylsubstituted salts of 4,4'-bipyridyl

    Science.gov (United States)

    Zakirov, M. I.; Efimov, N. N.; Mel'nikov, P. V.; Nodova, E. L.; Minin, V. V.

    2013-08-01

    Symmetric N, N'-disubstituted salts of 4,4'-bipyridyl (viologens) are synthesized and described. It is shown by cyclic voltammetry that disubstituted salts of 4,4'-bipyridyl have a tendency toward reversible two-electron reduction. Normal first and second step oxidation-reduction potentials with respect to saturated silver chloride electrodes at various potential scan rates are found. The spectra of the high-resolution electron paramagnetic resonance of viologen cation radicals formed during the reduction of N, N'-disubstituted salts of 4,4'-bipyridyl are obtained and interpreted. It is established that the nature of substitutes and counterions in a viologen molecule considerably influences the distribution of its spin density, voltammetric curves, and electro-optical properties.

  12. Fire behavior of carbonates-based electrolytes used in Li-ion rechargeable batteries with a focus on the role of the LiPF6 and LiFSI salts

    Science.gov (United States)

    Eshetu, Gebrekidan Gebresilassie; Bertrand, Jean-Pierre; Lecocq, Amandine; Grugeon, Sylvie; Laruelle, Stephane; Armand, Michel; Marlair, Guy

    2014-12-01

    A detailed investigation of the combustion behavior of LiPF6 or LiFSI-based carbonate electrolytes was conducted with the objective of getting better knowledge of lithium-ion battery system fire induced thermal and chemical threats. The well-controlled experimental conditions provided by the Tewarson calorimeter have enabled the accurate evaluation of fire hazard rating parameters such as heat release rate and effective heat of combustion and the quantification of toxic effluents (HF, SO2, NOx…). Results have shown that all the electrolytes tested burn in phases depending on the flammability nature of their mixture constituents. The first stage of combustion is solely governed by the more volatile solvent (linear carbonate) and the influence of adding salt comes into effect predominantly in the second stage. It has been also shown that combustion enthalpy of electrolytes lies in the solvent mixture, irrespective of the salt added. The fire induced toxicity in well-ventilated conditions is found to be mainly dictated by the salt and its chemical structure, showing very limited concerns that emanate from the organic solvents.

  13. Salt cookbook

    CERN Document Server

    Saha, Anirban

    2015-01-01

    If you are a professional associated with system and infrastructure management, looking at automated infrastructure and deployments, then this book is for you. No prior experience of Salt is required.

  14. H- beam emittance measurements for the penning and the asymmetric, grooved magnetron surface-plasma sources

    International Nuclear Information System (INIS)

    Beam-intensity and emittance measurements show that the H- beam from our Penning surface-plasma source (SPS) has twice the intensity and ten times the brightness of the H- beam from an asymmetric, grooved magnetron SPS. We deduce H- ion temperatures of 5 eV for the Penning SPS and 22 eV for the asymmetric, grooved magnetron

  15. Gene Expression, Protein Function and Pathways of Arabidopsis thaliana Responding to Silver Nanoparticles in Comparison to Silver Ions, Cold, Salt, Drought, and Heat

    Directory of Open Access Journals (Sweden)

    Eisa Kohan-Baghkheirati

    2015-03-01

    Full Text Available Silver nanoparticles (AgNPs have been widely used in industry due to their unique physical and chemical properties. However, AgNPs have caused environmental concerns. To understand the risks of AgNPs, Arabidopsis microarray data for AgNP, Ag+, cold, salt, heat and drought stresses were analyzed. Up- and down-regulated genes of more than two-fold expression change were compared, while the encoded proteins of shared and unique genes between stresses were subjected to differential enrichment analyses. AgNPs affected the fewest genes (575 in the Arabidopsis genome, followed by Ag+ (1010, heat (1374, drought (1435, salt (4133 and cold (6536. More genes were up-regulated than down-regulated in AgNPs and Ag+ (438 and 780, respectively while cold down-regulated the most genes (4022. Responses to AgNPs were more similar to those of Ag+ (464 shared genes, cold (202, and salt (163 than to drought (50 or heat (30; the genes in the first four stresses were enriched with 32 PFAM domains and 44 InterPro protein classes. Moreover, 111 genes were unique in AgNPs and they were enriched in three biological functions: response to fungal infection, anion transport, and cell wall/plasma membrane related. Despite shared similarity to Ag+, cold and salt stresses, AgNPs are a new stressor to Arabidopsis.

  16. Asymmetric synthesis v.4

    CERN Document Server

    Morrison, James

    1984-01-01

    Asymmetric Synthesis, Volume 4: The Chiral Carbon Pool and Chiral Sulfur, Nitrogen, Phosphorus, and Silicon Centers describes the practical methods of obtaining chiral fragments. Divided into five chapters, this book specifically examines initial chiral transmission and extension. The opening chapter describes the so-called chiral carbon pool, the readily available chiral carbon fragments used as building blocks in synthesis. This chapter also provides a list of 375 chiral building blocks, along with their commercial sources, approximate prices, and methods of synthesis. Schemes involving

  17. Two different molecular conformations found in chitosan type II salts.

    Science.gov (United States)

    Lertworasirikul, Amornrat; Tsue, Shin-ichiro; Noguchi, Keiichi; Okuyama, Kenji; Ogawa, Kozo

    2003-05-23

    The type II structure of chitosan acidic salts prepared from crab tendon in solid state was studied using an X-ray fiber diffraction technique together with the linked-atom least-squares (LALS) technique. The cylindrical Patterson method was applied to confirm the molecular conformation of the chitosan. It was shown that there are two different helical conformations for type II salts. One is the relaxed twofold helix having a tetrasaccharide as an asymmetric unit as found in chitosan.HCl salt, which was previously reported as a conformation of chitosan.HCOOH salt. The other is the fourfold helix having a disaccharide as an asymmetric unit newly found in chitosan.HI salt.

  18. RHIC operation with asymmetric collisions in 2015

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Aschenauer, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Atoian, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Connolly, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ottavio, T. D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Drees, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gardner, C. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hayes, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Laster, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Makdisi, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marr, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Montag, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Morris, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Narayan, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nayak, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nemesure, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pile, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Poblaguev, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roser, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schmidke, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Severino, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Shrey, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Smith, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Steski, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tepikian, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); White, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yip, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zaltsman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zeno, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhang, S. Y. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-08-07

    To study low-x shadowing/saturation physics as well as other nuclear effects [1], [2], proton-gold (p-Au, for 5 weeks) and proton-Aluminum (p-Al, for 2 weeks) collisions were provided for experiments in 2015 at the Relativistic Heavy Ion Collider (RHIC), with polarized proton beam in the Blue ring and Au/Al beam in the Yellow ring. The special features of the asymmetric run in 2015 will be introduced. The operation experience will be reviewed as well in the report.

  19. Novel FinFET Device Using Asymmetric Doping

    DEFF Research Database (Denmark)

    Moradi, Farshad

    2012-01-01

    In this paper, a new technique is proposed to improve the device characteristics by introducing asymmetric doping at the source and the drain of the conventional FinFET. Specifically, the proposed device exhibits 9X increase of the Ion/Ioff ratio and 3X improved DIBL compared to conventional...

  20. Asymmetric quantum cloning machines

    International Nuclear Information System (INIS)

    A family of asymmetric cloning machines for quantum bits and N-dimensional quantum states is introduced. These machines produce two approximate copies of a single quantum state that emerge from two distinct channels. In particular, an asymmetric Pauli cloning machine is defined that makes two imperfect copies of a quantum bit, while the overall input-to-output operation for each copy is a Pauli channel. A no-cloning inequality is derived, characterizing the impossibility of copying imposed by quantum mechanics. If p and p' are the probabilities of the depolarizing channels associated with the two outputs, the domain in (√p,√p')-space located inside a particular ellipse representing close-to-perfect cloning is forbidden. This ellipse tends to a circle when copying an N-dimensional state with N→∞, which has a simple semi-classical interpretation. The symmetric Pauli cloning machines are then used to provide an upper bound on the quantum capacity of the Pauli channel of probabilities px, py and pz. The capacity is proven to be vanishing if (√px, √py, √pz) lies outside an ellipsoid whose pole coincides with the depolarizing channel that underlies the universal cloning machine. Finally, the tradeoff between the quality of the two copies is shown to result from a complementarity akin to Heisenberg uncertainty principle. (author)

  1. Asymmetric inclusion process

    Science.gov (United States)

    Reuveni, Shlomi; Eliazar, Iddo; Yechiali, Uri

    2011-10-01

    We introduce and explore the asymmetric inclusion process (ASIP), an exactly solvable bosonic counterpart of the fermionic asymmetric exclusion process (ASEP). In both processes, random events cause particles to propagate unidirectionally along a one-dimensional lattice of n sites. In the ASEP, particles are subject to exclusion interactions, whereas in the ASIP, particles are subject to inclusion interactions that coalesce them into inseparable clusters. We study the dynamics of the ASIP, derive evolution equations for the mean and probability generating function (PGF) of the sites’ occupancy vector, obtain explicit results for the above mean at steady state, and describe an iterative scheme for the computation of the PGF at steady state. We further obtain explicit results for the load distribution in steady state, with the load being the total number of particles present in all lattice sites. Finally, we address the problem of load optimization, and solve it under various criteria. The ASIP model establishes bridges between statistical physics and queueing theory as it represents a tandem array of queueing systems with (unlimited) batch service, and a tandem array of growth-collapse processes.

  2. Electrostatic interactions of asymmetrically charged membranes

    Science.gov (United States)

    Ben-Yaakov, Dan; Burak, Yoram; Andelman, David; Safran, S. A.

    2007-08-01

    We predict the nature (attractive or repulsive) and range (exponentially screened or long-range power law) of the electrostatic interactions of oppositely charged, planar plates as a function of the salt concentration and surface charge densities (whose absolute magnitudes are not necessarily equal). An analytical expression for the crossover between attractive and repulsive pressure is obtained as a function of the salt concentration. This condition reduces to the high-salt limit of Parsegian and Gingell where the interaction is exponentially screened and to the zero salt limit of Lau and Pincus in which the important length scales are the inter-plate separation and the Gouy-Chapman length. In the regime of low salt and high surface charges we predict —for any ratio of the charges on the surfaces— that the attractive pressure is long-ranged as a function of the spacing. The attractive pressure is related to the decrease in counter-ion concentration as the inter-plate distance is decreased. Our theory predicts several scaling regimes with different scaling expressions for the pressure as a function of salinity and surface charge densities. The pressure predictions can be related to surface force experiments of oppositely charged surfaces that are prepared by coating one of the mica surfaces with an oppositely charged polyelectrolyte.

  3. The effect of organic salts on HPMC

    OpenAIRE

    Mongkolpiyawat, Jiraporn

    2012-01-01

    The presence of organic salts as drug counter-ions and buffers in hydroxypropylmethylcellulose (HPMC) matrices is often overlooked. This study investigates their potential to influence polymer solution properties and matrix drug release kinetics. A homologous series of aliphatic organic salts influenced solution and matrix properties in rank order of hydrocarbon chain length. Monovalent salts containing 1to4 C-atoms had little effect on polymer surface activity, but lowered sol:gel transit...

  4. Application of Boron-Based Lithium Salt for Li-Ion Battery%硼基锂盐电解质在锂离子电池中的应用

    Institute of Scientific and Technical Information of China (English)

    仇卫华; 阎坤; 连芳; 乔亚非

    2011-01-01

    Electrolyte is considered as one of the key materials to decide the performance of Li-ion batteries.Novel boron-based lithium salts have attracted people' s interests because of its varieties and environmental-friendly property. Lithium bis(oxalato) borate (LiBOB) , as one of boron-based lithium salts, is believed to be a candidate for commercial LiPF6 due to its good film-forming property and high thermal stability. In the paper, the new development of boron-based lithium salts is introduced, and LiBOB is also evaluated as lithium salt of electrolyte for Li-ion battery. The main influencing factors of LiBOB-based electrolyte are summarized. Especially, it has focused on the compatibility of LiBOB-based electrolyte with anode and metal oxide cathode. The application of LiBOBbased polymer electrolyte and LiBOB plastic chip electrolyte are introduced.%电解质材料是锂离子电池的关键材料之一,它直接影响电池的性能.新型硼酸锂盐由于种类繁多且环境友好而越来越引起人们的重视.双草酸硼酸锂(LiBOB)是一种新型的锂盐,具有很好的成膜性能和热稳定性,是一种很有潜力替代现有商品化锂盐LiPF6的物质.本文介绍了近期新型硼基锂盐的发展状况,归纳了LiBOB基电解质的研究概况,综述了影响LiBOB基电解质的因素,讨论了LiBOB与正负极材料的相容性,并对LiBOB基聚合物电解质和LiBOB塑晶电解质的应用进行了介绍.

  5. Effect of iron salt counter ion in dose-response curves for inactivation of Fusarium solani in water through solar driven Fenton-like processes

    Science.gov (United States)

    Aurioles-López, Verónica; Polo-López, M. Inmaculada; Fernández-Ibáñez, Pilar; López-Malo, Aurelio; Bandala, Erick R.

    2016-02-01

    The inactivation of Fusarium solani in water was assessed by solar driven Fenton-like processes using three different iron salts: ferric acetylacetonate (Fe(acac)3), ferric chloride (FeCl3) and ferrous sulfate (FeSO4). The experimental conditions tested were [Fe] ≈ 5 mg L-1, [H2O2] ≈ 10 mg L-1 and [Fe] ≈ 10 mg L-1; [H2O2] ≈ 20 mg L-1 mild and high, respectively, and pH 3.0 and 5.0, under solar radiation. The highest inactivation rates were observed at high reaction conditions for the three iron salts tested at pH 5.0 with less than 3.0 kJ L-1 of accumulate energy (QUV) to achieve over 99.9% of F. solani inactivation. Fe(acac)3 was the best iron salt to accomplishing F. solani inactivation. The modified Fermi equation was used to fix the experimental inactivation, data showed it was helpful for modeling the process, adequately describing dose-response curves. Inactivation process using FeSO4 at pH 3.0 was modeled fairly with r2 = 0.98 and 0.99 (mild and high concentration, respectively). Fe(acac)3, FeCl3 and FeSO4 at high concentration (i.e. [Fe] ≈ 10 mg L-1; [H2O2] ≈ 20 mg L-1) and pH 5.0 showed the highest fitting values (r2 = 0.99). Iron salt type showed a remarkable influence on the Fenton-like inactivation process.

  6. Effect of iron salt counter ion in dose-response curves for inactivation of Fusarium solani in water through solar driven Fenton-like processes

    Science.gov (United States)

    Aurioles-López, Verónica; Polo-López, M. Inmaculada; Fernández-Ibáñez, Pilar; López-Malo, Aurelio; Bandala, Erick R.

    2016-02-01

    The inactivation of Fusarium solani in water was assessed by solar driven Fenton-like processes using three different iron salts: ferric acetylacetonate (Fe(acac)3), ferric chloride (FeCl3) and ferrous sulfate (FeSO4). The experimental conditions tested were [Fe] ≈ 5 mg L-1, [H2O2] ≈ 10 mg L-1 and [Fe] ≈ 10 mg L-1; [H2O2] ≈ 20 mg L-1 mild and high, respectively, and pH 3.0 and 5.0, under solar radiation. The highest inactivation rates were observed at high reaction conditions for the three iron salts tested at pH 5.0 with less than 3.0 kJ L-1 of accumulate energy (QUV) to achieve over 99.9% of F. solani inactivation. Fe(acac)3 was the best iron salt to accomplishing F. solani inactivation. The modified Fermi equation was used to fix the experimental inactivation, data showed it was helpful for modeling the process, adequately describing dose-response curves. Inactivation process using FeSO4 at pH 3.0 was modeled fairly with r2 = 0.98 and 0.99 (mild and high concentration, respectively). Fe(acac)3, FeCl3 and FeSO4 at high concentration (i.e. [Fe] ≈ 10 mg L-1; [H2O2] ≈ 20 mg L-1) and pH 5.0 showed the highest fitting values (r2 = 0.99). Iron salt type showed a remarkable influence on the Fenton-like inactivation process.

  7. Crystal structure of the heptamolybdate(VI) (paramolybdate) ion, [Mo7O24]6-, in the ammonium and potassium tetrahydrate salts

    Science.gov (United States)

    Evans, H.T.; Gatehouse, B.M.; Leverett, P.

    1975-01-01

    The crystal structures of the isomorphous salts MI6 [Mo7O24],4H2O (M = NH4 or K) have been refined by three-dimensional X-ray diffraction methods. Unit cell dimensions of these monoclinic compounds, space group P21/C with Z = 4, are, ammonium salt: a = 8.3934 ?? 0.0008, b = 36.1703 ?? 0.0045, c = 10.4715 ?? 0.0011 A??, ?? = 115.958?? ?? 0.008??; and potassium salt: a = 8.15 ?? 0.02, b = 35.68 ?? 0.1, c = 10.30 ?? 0.02 A??, ?? = 115.2?? ?? 02??. By use of multiple Weissenberg patterns, 8197 intensity data (Mo-K?? radiation) for the ammonium compound and 2178 (Cu-K?? radiation) for the potassium compound were estimated visually and used to test and refine Lindqvist's proposed structure in the space group P21/c. Lindqvist's structure was confirmed and the full matrix least-squares isotropic refinement led to R 0.076 (ammonium) 0.120 (potassium), with direct unambiguous location of the cations and water molecules in the potassium compound.

  8. Alternative Asymmetric Stochastic Volatility Models

    NARCIS (Netherlands)

    M. Asai (Manabu); M.J. McAleer (Michael)

    2010-01-01

    textabstractThe stochastic volatility model usually incorporates asymmetric effects by introducing the negative correlation between the innovations in returns and volatility. In this paper, we propose a new asymmetric stochastic volatility model, based on the leverage and size effects. The model is

  9. Swelling of phospholipids by monovalent salt

    OpenAIRE

    Petrache, Horia I.; Tristram-Nagle, Stephanie; Harries, Daniel; Kučerka, Norbert; Nagle, John F.; Parsegian, V. Adrian

    2005-01-01

    Critical to biological processes such as membrane fusion and secretion, ion-lipid interactions at the membrane-water interface still raise many unanswered questions. Using reconstituted phosphatidylcholine membranes, we confirm here that multilamellar vesicles swell in salt solutions, a direct indication that salt modifies the interactions between neighboring membranes. By varying sample histories, and by comparing with data from ion carrier-containing bilayers, we eliminate the possibility t...

  10. Engineered Asymmetric Synthetic Vesicles

    Science.gov (United States)

    Lu, Li; Chiarot, Paul

    2013-11-01

    Synthetic vesicles are small, fluid-filled spheres that are enclosed by a bilayer of lipid molecules. They can be used as models for investigating membrane biology and as delivery vehicles for pharmaceuticals. In practice, it is difficult to simultaneously control membrane asymmetry, unilamellarity, vesicle size, vesicle-to-vesicle uniformity, and luminal content. Membrane asymmetry, where each leaflet of the bilayer is composed of different lipids, is of particular importance as it is a feature of most natural membranes. In this study, we leverage microfluidic technology to build asymmetric vesicles at high-throughput. We use the precise flow control offered by microfluidic devices to make highly uniform emulsions, with controlled internal content, that serve as templates to build the synthetic vesicles. Flow focusing, dielectrophoretic steering, and interfacial lipid self-assembly are critical procedures performed on-chip to produce the vesicles. Fluorescent and confocal microscopy are used to evaluate the vesicle characteristics.

  11. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  12. 多种盐分离子作用下苋菜对重金属的吸收累积特征%Absorption and Accumulation of Heavy Metals in Amaranth Under Stress of Multiple Salt Ions

    Institute of Scientific and Technical Information of China (English)

    张乾坤; 刘亚男; 李取生; 石雷; 王立立

    2012-01-01

    Reference to the salt and heavy metals content in the pore water of tidal flat soil which was in different leaching and desalinization stages, a hydroponic experiment of amaranth was carried out to investigate absorption, accumulation and transportation of six heavy metals (Zn, Cu, Ni, Cr, Pb and Cd) by the plant under the combined effect of a variety of salts (SO42- , Cl- , NO3- , CO32- , Na+ , Ca2+ , K+ and Mg2 + , etc. ). Results show that compared with what was observed in the control, under the effects of salt ions different in concentration, the content of Cd in stems and leaves of the plant increased by 69. 2% - 146. 2% , while the contents of other heavy metals did not change much; the content of Cd, Pb, Cr, Ni and Cu in roots of the plant increased by 187. 8% , 197. 7% , 305. 7% , 228. 1% and 58. 2% , respectively, but that of Zn was not significantly affected. In the culture solution with salt ion concentration being more than 1 312. 4 mg ? L ' , the contents of the six heavy metals in the roots and shoots did not vary much between treatments different in salt concentrations, separately. Salt treatment apparently reduced the translocation coefficients of Pb, Cr, Ni and Cu in amaranth from the roots to the shoots, but it did not affect much that of Cd and Zn.%模拟不同淋洗脱盐阶段滩涂土壤孔隙水中盐分和重金属含量,通过苋菜水培试验,研究多种盐分离子(SO42-、Cl-、NO3-、CO32-、Na+、Ca2、K+和Mg2等)的共同作用下,苋菜对Zn、Cu、Ni、Cr、Pb和Cd 6种重金属的吸收、累积和转运的变化.结果表明,与对照相比,在不同盐分离子浓度影响下,苋菜茎叶中Cd的累积增幅为69.2% ~ 146.2%,而茎叶中其他重金属的含量无显著变化,苋菜根系中Cd、Pb、Cr、Ni和Cu含量的最大增幅分别为187.8%、197.7%、305.7%、228.1%和58.2%,但根系中Zn含量未受到显著影响.在相对较高的盐分离子浓度( >1 312.4 mg·L-1)范围内,不同盐分离子

  13. 锂盐浓度对高功率锂离子电池性能的影响%Effect of lithium salt concentration on performance of high-rate discharge Li-ion battery

    Institute of Scientific and Technical Information of China (English)

    袁卉军; 陈真; 刘建生; 王姣丽

    2012-01-01

    考察了电解液中锂盐浓度对高功率锂离子电池倍率放电及高低温性能的影响.锂盐浓度为0.9~1.5 mol/L时,浓度越高越有利于大电流放电,但高于1.4 mol/L后,倍率放电中值电压的提升趋向平缓;在-20℃下以170 mA(1 C)放电,1.2 mol/L时的性能最好.%Effects of lithium salt concentration on rate discharge, high-low temperature performance of high-rate discharge Li-ion battery were investigated. When the lithium salt concentration was 0.9 ~ 1.5 mol/L, the higher concentration was benefit to heavy load discharge, but when higher than 1.4 mol/L, the increasing of rate discharge middle voltage trended gentle. When discharged with 1 C (170 mA) at - 20℃, the performance was the best with 1.2 mol/L.

  14. 锂离子电池电解质锂盐的发展历程和新型锂盐的研究进展%Development of Lithium Ion Battery Electrolyte and Research Progress of Novel Lithium Salts

    Institute of Scientific and Technical Information of China (English)

    闫春生; 李媛媛; 刘园园

    2016-01-01

    LiPF6 has become the most widely used commercial lithium battery electrolyte with brilliant ion-ic conductivity,better oxidation stability and less environmental pollution etc. Because LiPF6 thermal sta-bility is poor,the price is relatively expensive,the development and preparation of new lithium salts be-come a focus of attention for researchers. In this paper,the development of traditional lithium electrolyte is reviewed,the synthesis process of LiPF6 is summarized ,and research progress of new lithium salts is in-troduced.%六氟磷酸锂( LiPF6)因其突出的离子电导率、较优的氧化稳定性和较小的环境污染等优点成为目前使用最广泛的商业化锂电池电解质。由于LiPF6热稳定性较差、价格相对昂贵,使得新型锂盐的开发与制备成为研究者们关注的热点。本文回顾了传统锂盐电解质的发展,对LiPF6的合成工艺进行了综述,并介绍了新型锂盐的研究进展情况。

  15. The influence of salt formation on electrostatic and compression properties of flurbiprofen salts.

    Science.gov (United States)

    Supuk, Enes; Ghori, Muhammad U; Asare-Addo, Kofi; Laity, Peter R; Panchmatia, Pooja M; Conway, Barbara R

    2013-12-15

    Salt formation is an effective method of improving physicochemical properties of acidic and basic drugs. The selection of a salt form most suitable for drug development requires a well-designed screening strategy to ensure various issues are addressed in the early development stages. Triboelectrification of pharmaceutical powders may cause problems during processing such as segregation of components due to the effects of particle adhesion. However, very little work has been done on the effect of salt formation on triboelectrification properties. In this paper, salts of flurbiprofen were prepared by combining the drug with a selection of closely related amine counter ions. The aim of the work was to investigate the impact of the counter ion on electrostatic charge of the resultant salts to inform the salt selection process. The experimental results show the magnitude of charge and polarity of the flurbiprofen salts to be highly dependent on the type of counter ion selected for the salt formation. Furthermore, particle adhesion to the stainless steel surface of the shaking container and the salts' compression properties were measured. The formed salts had lower electrostatic charges, improved tabletability, and resulted in reduced adhesion of these powders compared with the parent drug.

  16. 不同盐度胁迫对芦荟生长和离子吸收分配的影响%Effects of Salt Concentration on Growth, Ion Absorption and Distribution of Aloe vera L.

    Institute of Scientific and Technical Information of China (English)

    马艳萍

    2012-01-01

    为探索芦荟对微咸水灌溉栽培的适应性,研究不同盐浓度对其生长和离子吸收分配的影响.结果表明,长期(120天)以含盐溶液灌溉栽培,盐浓度达200 mmol/L NaCl显著抑制芦荟生长,100 mmol/LNaCl对芦荟生长的抑制作用显著减轻,50 mmol/L NaCl不抑制芦荟生长.同时,以50 mmol/L NaCl溶液灌溉对芦荟盐分离子吸收分配影响轻微,但盐浓度达100 mmol/LNaCl对芦荟影响显著:根、茎、叶中K+含量显著下降,Na+、Cl-含量显著增大,K+/Na+大幅减小.X-射线能谱分析结果进一步表明,叶片贮水组织是芦荟积累盐分离子的重要部位,但100 mmol/L NaCl胁迫下芦荟根尖和叶片细胞中的离子平衡受到显著干扰.结果说明,芦荟适于用微咸水灌溉栽培,叶片贮水组织在缓解其盐胁迫中可起重要作用.%To explore the adaptability of irrigating aloe with weakly brine water, the effects of different concentration salinity stresses on growth, ion absorption and distribution of aloe plants were investigated.Experimental results showed that irrigation with 200 mmol/L NaCl for 120 d significantly retarded aloe growth, but the negative effects of irrigating aloe with 100 mmol/L NaCl on aloe growth were significantly relieved, even irrigating with 50 mmol/L NaCl did not retard aloe growth.The effects of irrigating with 50 mmol/L NaCl on ion absorption, transportation and distribution of aloe plants were not significant, but irrigating with 100 mmol/L NaCl were significant: K + contents of root, stem and leaf significantly decreased, Na + and Cl- content significantly increased, K+Na+ ratio significantly decreased.X-ray microanalysis results further showed that leaf aqueous was a main part of accumulating salt ion but ion homeostasis in root and leaf cells of aloe plants were significantly interrupted under 100 mmol/L NaCl stress.The experiment results suggested that Aloe vera L.was suitable to be irrigated with weakly brine water, and leaf

  17. Electrophysical methods of separation of metal cations in the moving salts solution

    Science.gov (United States)

    Gofman, V. N.; Tuksov, I. V.; Timchenko, S. N.; Shamanin, I. V.; Poberezhnikov, A. D.; Kazaryan, M. A.

    2016-07-01

    The results of experiments on the excitation of the phenomenon of selective drift of solvated ions under the influence of an external "asymmetric" electric field to the circulating solution of calcium chloride and magnesium salts in a polar liquid dielectric - water are shown. The purpose of the experiments was to determine the influence of the field frequency and amplitude of the field strength on the excitation phenomenon, and the study of the operating characteristics of the testing apparatus - a dividing cell. The dependences of the separation efficiency of solvated cations from the frequency of the external field and the excitation threshold of the phenomenon from the field strength in the separation cell are defined.

  18. Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: Theory, simulations, and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ovanesyan, Zaven; Marucho, Marcelo, E-mail: marcelo.marucho@utsa.edu [Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, Texas 78249-5003 (United States); Medasani, Bharat [Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, Texas 78249-5003 (United States); Computational Research Division, Lawrence Berkeley National Lab, Berkeley, California 94700 (United States); Fenley, Marcia O. [Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306 (United States); Guerrero-García, Guillermo Iván [Instituto de Física, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí (Mexico); Department of Chemistry and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Olvera de la Cruz, Mónica [Department of Chemistry and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-12-14

    The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules at experimental solvent concentrations. Our approach allows us to include ion correlations as well as solvent and ion excluded volume effects for studying the structural and thermodynamic properties of highly charged cylindrical polyelectrolytes. Several models of size and charge asymmetric mixtures of aqueous electrolytes at physiological concentrations are studied. Our results are in good agreement with Monte Carlo simulations. Our numerical calculations display significant differences in the ion density profiles for the different aqueous electrolyte models studied. However, similar results regarding the excess number of ions adsorbed to the B-DNA molecule are predicted by our theoretical approach for different aqueous electrolyte models. These findings suggest that ion counting experimental data should not be used alone to validate the performance of aqueous DNA-electrolyte models.

  19. Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: Theory, simulations, and experiments

    International Nuclear Information System (INIS)

    The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules at experimental solvent concentrations. Our approach allows us to include ion correlations as well as solvent and ion excluded volume effects for studying the structural and thermodynamic properties of highly charged cylindrical polyelectrolytes. Several models of size and charge asymmetric mixtures of aqueous electrolytes at physiological concentrations are studied. Our results are in good agreement with Monte Carlo simulations. Our numerical calculations display significant differences in the ion density profiles for the different aqueous electrolyte models studied. However, similar results regarding the excess number of ions adsorbed to the B-DNA molecule are predicted by our theoretical approach for different aqueous electrolyte models. These findings suggest that ion counting experimental data should not be used alone to validate the performance of aqueous DNA-electrolyte models

  20. Asymmetric Gepner Models (Revisited)

    CERN Document Server

    Gato-Rivera, B

    2010-01-01

    We reconsider a class of heterotic string theories studied in 1989, based on tensor products of N=2 minimal models with asymmetric simple current invariants. We extend this analysis from (2,2) and (1,2) spectra to (0,2) spectra with SO(10) broken to the Standard Model. In the latter case the spectrum must contain fractionally charged particles. We find that in nearly all cases at least some of them are massless. However, we identify a large subclass where the fractional charges are at worst half-integer, and often vector-like. The number of families is very often reduced in comparison to the 1989 results, but there are no new tensor combinations yielding three families. All tensor combinations turn out to fall into two classes: those where the number of families is always divisible by three, and those where it is never divisible by three. We find an empirical rule to determine the class, which appears to extend beyond minimal N=2 tensor products. We observe that distributions of physical quantities such as th...

  1. Magnetically Modified Asymmetric Supercapacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is for the development of an asymmetric supercapacitor that will have improved energy density and cycle...

  2. Ion colliders

    International Nuclear Information System (INIS)

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions (77Asb1, 81Bou1). The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

  3. Multicatalyst system in asymmetric catalysis

    CERN Document Server

    Zhou, Jian

    2014-01-01

    This book introduces multi-catalyst systems by describing their mechanism and advantages in asymmetric catalysis.  Helps organic chemists perform more efficient catalysis with step-by-step methods  Overviews new concepts and progress for greener and economic catalytic reactions  Covers topics of interest in asymmetric catalysis including bifunctional catalysis, cooperative catalysis, multimetallic catalysis, and novel tandem reactions   Has applications for pharmaceuticals, agrochemicals, materials, and flavour and fragrance

  4. On Asymmetric Quantum MDS Codes

    CERN Document Server

    Ezerman, Martianus Frederic; Ling, San

    2010-01-01

    Assuming the validity of the MDS Conjecture, the weight distribution of all MDS codes is known. Using a recently-established characterization of asymmetric quantum error-correcting codes, linear MDS codes can be used to construct asymmetric quantum MDS codes with $d_{z} \\geq d_{x}\\geq 2$ for all possible values of length $n$ for which linear MDS codes over $\\F_{q}$ are known to exist.

  5. Mobile Termination with Asymmetric Networks

    OpenAIRE

    Dewenter, Ralf; Haucap, Justus

    2003-01-01

    This paper examines mobile termination fees and their regulation when networks are asymmetric in size. It is demonstrated that with consumer ignorance about the exact termination rates (a) a mobile network?s termination rate is the higher the smaller the network?s size (as measured through its subscriber base) and (b) asymmetric regulation of only the larger operators in a market will, ce-teris paribus, induce the smaller operators to increase their termination rates. The results are supporte...

  6. Asymmetric Gepner models (revisited)

    Energy Technology Data Exchange (ETDEWEB)

    Gato-Rivera, B. [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands)] [Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain); Schellekens, A.N., E-mail: t58@nikhef.n [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands)] [Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain)] [IMAPP, Radboud Universiteit, Nijmegen (Netherlands)

    2010-12-11

    We reconsider a class of heterotic string theories studied in 1989, based on tensor products of N=2 minimal models with asymmetric simple current invariants. We extend this analysis from (2,2) and (1,2) spectra to (0,2) spectra with SO(10) broken to the Standard Model. In the latter case the spectrum must contain fractionally charged particles. We find that in nearly all cases at least some of them are massless. However, we identify a large subclass where the fractional charges are at worst half-integer, and often vector-like. The number of families is very often reduced in comparison to the 1989 results, but there are no new tensor combinations yielding three families. All tensor combinations turn out to fall into two classes: those where the number of families is always divisible by three, and those where it is never divisible by three. We find an empirical rule to determine the class, which appears to extend beyond minimal N=2 tensor products. We observe that distributions of physical quantities such as the number of families, singlets and mirrors have an interesting tendency towards smaller values as the gauge groups approaches the Standard Model. We compare our results with an analogous class of free fermionic models. This displays similar features, but with less resolution. Finally we present a complete scan of the three family models based on the triply-exceptional combination (1,16{sup *},16{sup *},16{sup *}) identified originally by Gepner. We find 1220 distinct three family spectra in this case, forming 610 mirror pairs. About half of them have the gauge group SU(3)xSU(2){sub L}xSU(2){sub R}xU(1){sup 5}, the theoretical minimum, and many others are trinification models.

  7. Short communication. Suitable growth stage to start irrigation with saline water to increase salt tolerance and decrease ion accumulation of Kochia scoparia (L. Schrad)

    Energy Technology Data Exchange (ETDEWEB)

    Salehi, M.; Kafi, M.

    2011-07-01

    Kochia scoparia L. Schard (common name: kochia) is a mesohalophyte, C4 plant. It has the potential of being an important fodder crop in arid and semi arid environments. In order to evaluate the effect of saline irrigation water on the seedling growth stage and to select the best growth stage to start using saline water, an experiment was conducted with seven different saline water treatments (1.5, 7, 14, 21, 28, 35 and 42 dS m{sup -}1) at four growth stages [after emergence (T1), 5 cm (T2), 10 cm (T3), and 15 cm (T4) of plant height]. Results showed that shoot dry biomass increased slightly up to 7 dS m{sup -}1 and after that decreased with increasing salinity. Salt tolerance of kochia increased at the T3 and T4 growth stages. Sodium content of the plant was increased by using high saline water. The adverse effect of salinity on the Na content of the plant was lower at the 10-15 cm growth stage than at earlier growth stages. Potassium content was not greatly affected by salinity. As conclusion, kochia is sensitive to saline irrigation at the earliest stages of growth, and the best plant height to start saline irrigation is between 10 and 15 cm. (Author) 18 refs.

  8. Novel synthetic approach for 1, 4-dihydroxyanthraquinone and the development of its Lithiated salts as anode material for aqueous rechargeable Lithium-ion batteries

    KAUST Repository

    Gurukar, Suresh Shivappa

    2015-08-17

    The influence of organic electrode materials in the field of lithium ion battery is becoming a keen interest for the present generation scientists. Here we are reporting a novel method of synthesis of electrode material by the combination of sono-chemical and thermal methods. The advantages of organic active material towards lithium ion battery are of core interest of this study. The structural confirmations are by FT-IR, 1H NMR, MALDI-TOF Mass Spectroscopy and powder XRD data. The electrochemical properties of Lithiated-1,4-dihydroxyanthraquinone were studied using electrochemical-techniques such as Cyclic Voltammetry, Galvanostatic Cyclic Potential Limitation and Potentiostatic Electrochemical Impedance Spectroscopy. The satisfactory results towards stability of active species in the aqueous media, reasonable discharge capacity with 0.9 V average voltages and agreeable cycling performance during charge-discharge process with reproducibility are achieved. For the construction of the full cell, the anode material was coupled with the LiNi1/3Co1/3Mn1/3O2 as a cathode material.

  9. 盐胁迫对油葵幼苗生长及离子吸收、分布的影响%Impact of Salt Stress on Growth and Ion Uptake of Different Parts of Oil Sunflower Seedlings

    Institute of Scientific and Technical Information of China (English)

    杨晓翠; 李文建; 曲颖; 张天虎

    2011-01-01

    [目的]研究不同NaCl浓度对油葵幼苗干、鲜重变化及离子吸收和分布的影响.[方法]不同浓度NaCl溶液模拟盐胁迫环境,测定油葵幼苗干、鲜重及离子含量.[结果]NaCl胁迫抑制油葵幼苗生长,降低了幼苗干、鲜重.叶片鲜重下降最明显,200mmol/L NaCl时下降约60%;子叶鲜重下降最少,200mmol/L NaCl时下降约13%.干重的下降程度同鲜重相似,200 mmol/L NaCl时根、茎、叶、子叶的干重与对照组相比分别下降约35%、39%、55%和8%.NaCl胁迫下,油葵幼苗根和茎中Na+含量上升,K+含量下降;Na+主要集中在根和茎中,叶片中较少;根中K+含量下降最明显,叶片中K+含量相对较高.根和茎中Ca2+、Mg2+含量下降,叶片和子叶中Ca2+含量相对稳定,子叶中Mg2+含量略上升.[结论]葵幼苗在NaCl胁迫下保持较高的矿物质元素吸收和运输以及相对稳定的离子平衡,这可能是油葵具有较高耐盐性的部分原因.%[Objective]The purpose was to discuss the effects of different NaCl concentrations on fresh weight and dry weight, ion absorption and distribution in oil sunflower seedlings.[Method]Under the simulated salt environment by using NaCl solutions at different concentrations,the dry weight, fresh weight and ion content of oil sunflower seedlings were determined.[Result]With the increase of NaCl concentration, the growth rate of oil sunflower seedling was inhibited.In addition, its fresh weight and dry weight also decreased; the fresh weight of leaf decreased most significantly by 60%, and that of cotyledon decreased most slightly by 13% at 200 mmol/L NaCl concentration.The dry weight of root,stem, leaf and cotyledon decreased by 35%, 39%, 55% and 8% respectively, showing a similar decreasing trend with fresh weight.Under NaCl stress, Na+ content in root and stem of oil sunflower seedling increased white K+ decreased.Na+ content was mainly concentrated in roots and stems much more than in leaves; K+ content

  10. 盐胁迫对油葵幼苗生长及离子吸收·分布的影响%Impact of Salt Stress on Growth and Ion Uptake of Different Parts of Oil Sunflower Seedlings

    Institute of Scientific and Technical Information of China (English)

    杨晓翠; 李文建; 曲颖; 张天虎

    2011-01-01

    [ Objective ] The purpose was to discuss the effects of different NaCl concentrations on fresh weight and dry weight,ion absorption and distribution in oil sunflower seedlings. [ Method ] Under the simulated salt environment by using NaCl solutions at different concentrations,the dry weight ,fresh weight and ion content of oil sunflower seedlings were determined. [ Result ] With the increase of NaCl concentration, the growth rate of oil sunflower seedling was inhibited. In addition ,its fresh weight and dry weight also decreased; the fresh weight of leaf decreased most significantly by 60% ,and that of cotyledon decreased most slightly by 13% at 200 mmol/L NaCl concentration. The dry weight of root,stem,leaf and cotyledon decreased by 35% ,39% ,55% and 8% respectively,showing a similar decreasing trend with fresh weight. Under NaCl stress,Na+ content in root and stem of oil sunflower seedling increased while K + decreased. Na+ content was mainly concentrated in roots and stems much more than in leaves; K + content in roots decreased most significantly by 21% compared with control ,and it was relatively high in leaf. Ca2+ and Mg2+ content was decreased slightly in roots and stems;Ca2+ content in leaves and cotyledons was stable;Mg2+ content was slightly increased. [ Conclusion ] Oil sunflower maintained high mineral ion absorption under salt stress, that maybe the part reason for high salt tolerance of oil sunflower seedlings.%[目的]研究不同浓度NaCl对油葵幼苗干、鲜重及离子吸收和分布的影响.[方法]采用不同浓度NaCl溶液模拟盐胁迫环境,测定油葵幼苗干、鲜重及离子含量.[结果]NaCl胁迫抑制油葵幼苗生长,降低了幼苗干、鲜重.叶片鲜重下降最明显,200mmol/L NaCl胁迫时下降约60%;子叶鲜重下降最少,200mmol/L NaCl时下降约13%.干重的下降程度同鲜重相似1200mmol/L NaCl胁迫时,根、茎、叶、子叶的干重与对照组相比分别下降约35%,39%,55%和8%.NaCl

  11. Detection, identification, and occurrence of thiotetronic acids in drinking water from underground sources by electrospray ionization-high field asymmetric waveform ion mobility spectrometry-quadrupole time-of-flight-mass spectrometry.

    Science.gov (United States)

    Lyczko, Jadwiga; Beach, Daniel; Gabryelski, Wojciech

    2015-10-01

    This paper demonstrates that electrospray ionization (ESI) with differential ion mobility spectroscopy (FAIMS) and "soft" mass spectrometry (MS) provide unique analytical capabilities that led to the discovery of sulfur-containing polar congeners of thiotetronic acid (TA) in drinking water from underground sources in Canada and the United States. Polar TAs accumulate in underground aquifers and appear to be the most abundant class of organic compounds in bottled water but cannot be detected by conventional mass spectrometry methods. We show that normally stable TAs are converted into very reactive ions in ESI which have to be analyzed using special conditions in ESI-FAIMS-MS to avoid extensive dissociation and ion/molecule reactions. De novo identification of 10 TAs was accomplished by the comparative tandem mass spectrometry analysis of authentic TA derivatives from groundwater samples and synthetic TA analogues prepared for this study. We present highlights of gas phase ion chemistry of polar TAs to explain their unique properties and reactivity. TA derivatives were originally isolated from soil bacteria and are of interest in the pharmaceutical industry due to their potent activity against a broad spectrum of pathogenic bacteria and negligible toxicity to mammals. We suspect that TAs are natural disinfection agents protecting groundwater from bacterial contamination, but these compound undergo modifications or decompose during an ozonation water treatment.

  12. Detection, identification, and occurrence of thiotetronic acids in drinking water from underground sources by electrospray ionization-high field asymmetric waveform ion mobility spectrometry-quadrupole time-of-flight-mass spectrometry.

    Science.gov (United States)

    Lyczko, Jadwiga; Beach, Daniel; Gabryelski, Wojciech

    2015-10-01

    This paper demonstrates that electrospray ionization (ESI) with differential ion mobility spectroscopy (FAIMS) and "soft" mass spectrometry (MS) provide unique analytical capabilities that led to the discovery of sulfur-containing polar congeners of thiotetronic acid (TA) in drinking water from underground sources in Canada and the United States. Polar TAs accumulate in underground aquifers and appear to be the most abundant class of organic compounds in bottled water but cannot be detected by conventional mass spectrometry methods. We show that normally stable TAs are converted into very reactive ions in ESI which have to be analyzed using special conditions in ESI-FAIMS-MS to avoid extensive dissociation and ion/molecule reactions. De novo identification of 10 TAs was accomplished by the comparative tandem mass spectrometry analysis of authentic TA derivatives from groundwater samples and synthetic TA analogues prepared for this study. We present highlights of gas phase ion chemistry of polar TAs to explain their unique properties and reactivity. TA derivatives were originally isolated from soil bacteria and are of interest in the pharmaceutical industry due to their potent activity against a broad spectrum of pathogenic bacteria and negligible toxicity to mammals. We suspect that TAs are natural disinfection agents protecting groundwater from bacterial contamination, but these compound undergo modifications or decompose during an ozonation water treatment. PMID:26340067

  13. Salt Effect on Osmotic Pressure of Polyelectrolyte Solutions: Simulation Study

    Directory of Open Access Journals (Sweden)

    Jan-Michael Y. Carrillo

    2014-07-01

    Full Text Available Abstract: We present results of the hybrid Monte Carlo/molecular dynamics simulations of the osmotic pressure of salt solutions of polyelectrolytes. In our simulations, we used a coarse-grained representation of polyelectrolyte chains, counterions and salt ions. During simulation runs, we alternate Monte Carlo and molecular dynamics simulation steps. Monte Carlo steps were used to perform small ion exchange between simulation box containing salt ions (salt reservoir and simulation box with polyelectrolyte chains, counterions and salt ions (polyelectrolyte solution. This allowed us to model Donnan equilibrium and partitioning of salt and counterions across membrane impermeable to polyelectrolyte chains. Our simulations have shown that the main contribution to the system osmotic pressure is due to salt ions and osmotically active counterions. The fraction of the condensed (osmotically inactive counterions first increases with decreases in the solution ionic strength then it saturates. The reduced value of the system osmotic coefficient is a universal function of the ratio of the concentration of osmotically active counterions and salt concentration in salt reservoir. Simulation results are in a very good agreement with osmotic pressure measurements in sodium polystyrene sulfonate, DNA, polyacrylic acid, sodium polyanetholesulfonic acid, polyvinylbenzoic acid, and polydiallyldimethylammonium chloride solutions.

  14. Asymmetric distances for binary embeddings.

    Science.gov (United States)

    Gordo, Albert; Perronnin, Florent; Gong, Yunchao; Lazebnik, Svetlana

    2014-01-01

    In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes that binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances that are applicable to a wide variety of embedding techniques including locality sensitive hashing (LSH), locality sensitive binary codes (LSBC), spectral hashing (SH), PCA embedding (PCAE), PCAE with random rotations (PCAE-RR), and PCAE with iterative quantization (PCAE-ITQ). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques.

  15. Determination of iodine in table salt by iodide ion selective electrode%碘离子选择电极快速测定食盐中碘的含量

    Institute of Scientific and Technical Information of China (English)

    李玉成; 姚静

    2011-01-01

    This paper describes a rapid iodine content measure method by using the iodide ion selective electrode under a reducing buffer environment. With Na2SO3 as reducing agent and the buffer solution of 0.1 mol/L KNO^(3-)0.01moL/L tartaric acid, IO^(3-)is reduced to I^-. The iodide ion could be detected by the selective electrode with potentiometry. Then the detection result is compared with standard curved to determine the salt iodine content. The linear measurement interval is 10^(-1)~ 10^(-7) mol/L with the minimum detects concentration of 4.6 × 10^(-8)mol/L. The recovery coefficient is 98.2% - 100.7%.%利用碘离子选择电极,以0.1mol/LKNO(3^-)0.01mol/L酒石酸为总离子强度调节荆、Na2SO3为还原保护剂,将加碘食盐中的10(3^-)还原为I^-,在双液接饱和甘汞电极为参比电极的条件下,采用直接电位法和标准曲线法直接测定了溶液中的碘含量,实验结果表明,本方法线性范围10^(-1)~10^(-7)mol/L,检测下限4.6×10^(-8)mol/L,样品具有较好的回收率(98.2%-100.7%),可以用此方法测定食盐中I^-的含量。

  16. Solvent-assisted molten salt process: A new route to synthesise {alpha}-Fe{sub 2}O{sub 3}/C nanocomposite and its electrochemical performance in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Mohd Faiz, E-mail: mfh125@uow.edu.a [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); Department of Science Physics, University of Malaysia Terengganu, Kuala Terengganu 20522 (Malaysia); Rahman, M.M. [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); Guo, Zai Ping [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia); School of Mechanical, Mechatronic and Materials Engineering, University of Wollongong, NSW 2522 (Australia); Chen, Zhi Xin [School of Mechanical, Mechatronic and Materials Engineering, University of Wollongong, NSW 2522 (Australia); Liu, Hua Kun [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2522 (Australia)

    2010-07-01

    Nanostructured {alpha}-Fe{sub 2}O{sub 3} was synthesised by a simple molten salt process using FeCl{sub 2}.4H{sub 2}O as a starting material and LiNO{sub 3}-LiOH.H{sub 2}O-H{sub 2}O{sub 2} as a eutectic mixture at 300 {sup o}C. To synthesise {alpha}-Fe{sub 2}O{sub 3}/C composite, both {alpha}-Fe{sub 2}O{sub 3} and malic acid were dispersed together in toluene, where malic acid was used as a carbon source. The morphology and microstructure of both compounds were confirmed by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. Electrochemical testing, including constant current charge-discharge and cyclic voltammetry (CV), was carried out. The {alpha}-Fe{sub 2}O{sub 3}/C composite anode exhibited much better electrochemical performance than the bare {alpha}-Fe{sub 2}O{sub 3}. The discharge capacities of the composite were measured to be 2112 mAh g{sup -1} at C/2 after 100 cycles and 584 mAh g{sup -1} at 20 C after 10 cycles. The superior electrochemical performance of {alpha}-Fe{sub 2}O{sub 3}/C composite can be mainly attributed to the combined effects of the nanostructure, the carbon layering on the {alpha}-Fe{sub 2}O{sub 3} nanoparticles, and the porous ultra-fine carbon matrix, where the three factors would contribute to provide high electronic conductivity, reduce the traverse time of electrons and lithium-ions, and could also prevent high volume expansion of the anode film during cycling. Our results indicate that the prepared {alpha}-Fe{sub 2}O{sub 3}/C nanocomposite is a very promising anode material for Li-ion power batteries.

  17. Asymmetric Synthesis via Chiral Aziridines

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Harden, Adrian; Wyatt, Paul;

    1996-01-01

    A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines)]. In the b......A series of chiral bis(aziridines) has been synthesised and evaluated as chelating ligands for a variety of asymmetric transformations mediated by metals [Os (dihydroxylation), Pd (allylic alkylation) Cu (cyclopropanation and aziridination, Li (1,2-addition of organolithiums to imines...

  18. Ideal 3D asymmetric concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Botella, Angel [Departamento Fisica Aplicada a los Recursos Naturales, Universidad Politecnica de Madrid, E.T.S.I. de Montes, Ciudad Universitaria s/n, 28040 Madrid (Spain); Fernandez-Balbuena, Antonio Alvarez; Vazquez, Daniel; Bernabeu, Eusebio [Departamento de Optica, Universidad Complutense de Madrid, Fac. CC. Fisicas, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2009-01-15

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used for producing reflective and refractive optical devices, including reverse engineering techniques. In this paper we apply photometric field theory and elliptic ray bundles method to study 3D asymmetric - without rotational or translational symmetry - concentrators, which can be useful components for nontracking solar applications. We study the one-sheet hyperbolic concentrator and we demonstrate its behaviour as ideal 3D asymmetric concentrator. (author)

  19. Incompressibility of asymmetric nuclear matter

    OpenAIRE

    Chen, Lie-Wen; Cai, Bao-Jun; Shen, Chun; Ko, Che Ming; Xu, Jun; Li, Bao-An(Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, TX, 75429-3011, USA)

    2009-01-01

    The incompressibility $K_sat(\\delta)$ of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of $K_sat(\\delta)$ in powers of isospin asymmetry $\\delta$, i.e., $K_sat(\\delta )$=K_{0}+K_{sat,2}\\delta^{2}+K_{sat,4}\\delta^{4}+O(\\delta^{6})$, the magnitude of the 4th-order K_{sat,4} parameter is generally small. The 2nd-order K_{sat,2} parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matte...

  20. Forces between asymmetric polymer brushes

    OpenAIRE

    Shim, D.F.K.; Cates, M. E.

    1990-01-01

    We study the equilibrium compression of asymmetric polymer brushes grafted on flat plates, under athermal and theta solvent conditions, using a lattice self-consistent field (SCF) approach. We find that the separation d between two plates coated asymmetrically with brushes of type 1 and 2, as a function of the force F, obeys the "bisection rule", d(F) = (d1(F) + d 2(F)) /2 where d1(F)and d 2(F) are the corresponding separations for the symmetric brushes of type 1 and 2 respectively.The bisect...

  1. Research on asymmetric "Jerusalem" unit

    Institute of Scientific and Technical Information of China (English)

    Jun Lu; Jianbo Wang

    2009-01-01

    An asymmetric Jerusalem unit and the frequency selective surface(FSS)structure composed of such units are designed.The transmittance of the designed FSS structure is calculated by mode-matching method and compared with the test results.The comparison results show that the FSS center frequency of the asymmetric structure unit drifts little with the variation of the incident angles of the electromagnetic waves and keeps relatively stable.The research offers a new choice for the application of FSS under the large scanning angle of electromagnetic waves.

  2. Salt resistant crop plants

    KAUST Repository

    Roy, Stuart J.

    2014-04-01

    Soil salinity is a major constraint to agriculture. To improve salinity tolerance of crops, various traits can be incorporated, including ion exclusion, osmotic tolerance and tissue tolerance. We review the roles of a range of genes involved in salt tolerance traits. Different tissues and cells are adapted for specific and often diverse function, so it is important to express the genes in specific cell-types and to pyramid a range of traits. Modern biotechnology (marker- assisted selection or genetic engineering) needs to be increasingly used to introduce the correct combination of genes into elite crop cultivars. Importantly, the effects of introduced genes need to be evaluated in the field to determine their effect on salinity tolerance and yield improvement.

  3. The Design of Reactions, Catalysts and Materials with Aromatic Ions

    Science.gov (United States)

    Bandar, Jeffrey Scott

    (dialkylamino)cyclopropenimine catalyst to promote asymmetric Mannich reactions of glycinate imines and N -Boc-aldimines is described in Chapter 4. The products of this transformation are optically enriched diamino acid derivatives, an important motif widely utilized in medicinal and synthetic chemistry. Importantly, unlike existing methods, our technology promotes reactions between tert-butyl glycinate and aliphatic N-Boc-aldimine substrates. A preparative-scale reaction is demonstrated and derivatization of its product to several valuable chiral compounds is shown. Chapter 5 describes the use of tris(dialkylamino)cyclopropenium (TDAC) ions as a new class of onium-like catalyst. A simple TDAC chloride salt is prepared on a 75-gram scale and its use as a phase transfer catalyst for a variety of reactions is demonstrated. This same salt is also utilized as an epoxide opening catalyst for a variety of transformations, including the fixation of carbon dioxide. Chapter 6 briefly highlights several continued applications of the chemistry advanced throughout this thesis. First, the work of other members of the Lambert Group toward the continued development of cyclopropenimine chemistry is described. Second, a broad initiative between the Lambert and Campos Groups at Columbia University focused on the synthesis and application of TDAC-based polymers is introduced. Lastly, the identification of a previously unknown equilibrium between fulvenes and imines/aldehydes in the context of a new mode of catalysis is presented.

  4. Effect of the difference in ion mobilities on traveling-wave electro-osmosis

    CERN Document Server

    Gonzalez, Antonio; Garcia-Sanchez, Pablo; Castellanos, Antonio

    2008-01-01

    We analyze the AC electro-osmotic motion of a 1:1 aqueous solution, taking into account the difference in mobilities and diffusion coefficients between positive and negative ions. This model serves to understand the behavior of common systems as a solution of NaCl in water. We pay special attention to two cases. First, the case of slightly different mobilities, that can model a KCl solution. Second, the case of a strongly asymmetric solution, with an almost vanishing mobility, applicable to the case of a salt where the negative ion is much more massive than the positive one. For all the cases, we perform the mathematical description and linear analysis of the problem, in order to establish the dependence of the induced velocity with the frequency, wavelength and amplitude of the applied voltage.

  5. Synthesis of Asymmetric Propanetriol Analogues

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    From natural tartaric acid, (R)-2-benzyloxy-3-(2-tetrahydropyranyloxy) propanol 3 was designed and synthesized, and (R)-2-benzyloxy-3-(4-methoxybenzyloxy) propanol 7 was prepared in a new method. They can be used as chiral synthons of lysophosphatidic acid and other compounds with asymmetric propanetriol backbone.

  6. Vertical asymmetric double quantum dots

    Science.gov (United States)

    Roßbach, R.; Reischle, M.; Beirne, G. J.; Schweizer, H.; Jetter, M.; Michler, P.

    2007-01-01

    Two layers of differently sized self-assembled InP-quantum dots (QDs) separated by a GaInP spacer layer with varying thickness were grown by metal organic vapor phase epitaxy (MOVPE). Photoluminescence measurements of the QD ensembles and of individual asymmetric double QDS show coupling due to the tunnelling of carriers.

  7. Asymmetrical Switch Costs in Children

    Science.gov (United States)

    Ellefson, Michelle R.; Shapiron, Laura R.; Chater, Nick

    2006-01-01

    Switching between tasks produces decreases in performance as compared to repeating the same task. Asymmetrical switch costs occur when switching between two tasks of unequal difficulty. This asymmetry occurs because the cost is greater when switching to the less difficult task than when switching to the more difficult task. Various theories about…

  8. [The morphological structure of salt gland and salt secretion in Aeluropus littoralis var. sinensis Debeaux].

    Science.gov (United States)

    Liu, Zhi-Hua; Shi, Li-Ran; Zhao, Ke-Fu

    2006-08-01

    The leaves of Aeluropus littoralis var. sinensis Debeaux were scanned with a scanning electron microscope, it showed that the upper-epidermis had almost the same number of salt glands as the lower-epidermis (Plate I-1, 2), and the salt gland is the typical bicelluar gland, which consists of a large basal cell inlaid into the epidermis and a small cap cell (Plate I-6). These salt glands were distributed mainly on the leaf veins, which favors the rapid collection of salts from the roots. Ion X-ray microanalysis indicated that the salt glands could effectively absorb Na(+) from the epidermal cells and mesophyllous cells (Table 1), then secreted Na(+) from the cap cells (Plate I-4), which would decrease the salinity of plant. After the plants were treated with various salts for 17 d, the ion contents of the leaves and the secretion were measured, and the results implied that salt glands had different selection in absorbing and secreting Na(+) , K(+) and Ca(2+), that is, the plants first selected K(+) when absorbing ions, while first selected Na(+) when sending ions out, but Ca(2+) was fewer in both absorbed and secreted, and the order of secretion of the three ions was found to be Na(+)>K(+)>Ca(2+) (Figs. 1-6). The secretion of Na(+) or three ions were respectively higher than that of leaves within 24 h (Figs. 1, 2, 7, 8), while K(+) situation was completely opposite with them (Figs. 3, 4). At the same time, the total ion content and composition inside the leaves remained more or less constant (Fig. 8). PMID:16957392

  9. Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

    Directory of Open Access Journals (Sweden)

    Nadin Pade

    2014-12-01

    Full Text Available The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants.

  10. Selfhealing of asymmetric Bessel-like modes

    DEFF Research Database (Denmark)

    Israelsen, Stine Møller; Rishøj, Lars Søgaard; Rottwitt, Karsten

    2014-01-01

    We numerically investigate asymmetric Bessel-like modes in an aircladding fiber. The selfhealing ability of asymmetric Bessel-like modes is demonstrated and quantified including the angular dependency of this ability.......We numerically investigate asymmetric Bessel-like modes in an aircladding fiber. The selfhealing ability of asymmetric Bessel-like modes is demonstrated and quantified including the angular dependency of this ability....

  11. SINGLE IONIC CONDUCTION OF POLYSILOXANE CONTAINING PROPYLENE CARBONATE GROUP AND LITHIUM POLYMERIC SALTS

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiwen; FANG Shibi; HAO Ning; JIANG Yingyan

    1996-01-01

    The polysiloxane containing propylene carbonate side group and several lithium polymeric salts were synthesized. The structure were confirmed by IR, NMR and XPS. The blending systems of polysiloxane containing propylene carbonate group with different lithium polymeric salts were studied by ion conductivity, XPS and DSC. Different lithium polymeric salts in the blending system lead to conductivity arranged in the following sequence:poly(lithium ethylenebenzene sulfonate methylsiloxane) > poly(lithium propionate methylsiloxane) > poly(lithium propylsulfonate methylsiloxane) > poly(lithium styrenesulfonate).In the blending system the best single ion conductivity was close to 10-5 Scm-1 at room temperature. XPS showed that at low lithium salt concentration the conductivity increased with the increasing content of lithium salt, in consequence of the increase of free ion and solvent separated ion pair. At high lithium salt concentration the free ion was absent and the solvent-separated ion pair functioned as carrier.

  12. The structure and IR signatures of the arginine-glutamate salt bridge. Insights from the classical MD simulations.

    Science.gov (United States)

    Vener, M V; Odinokov, A V; Wehmeyer, C; Sebastiani, D

    2015-06-01

    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)-glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898-915 (2011)]. These structures are stabilized by the short (+)N-H⋯O(-) bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm(-1). It is caused by the asymmetric stretching vibrations of the (+)N-H⋯O(-) fragment. Result of the present paper suggests that infrared spectroscopy in the 2000-2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is usually not considered in spectroscopic

  13. The structure and IR signatures of the arginine-glutamate salt bridge. Insights from the classical MD simulations

    Energy Technology Data Exchange (ETDEWEB)

    Vener, M. V., E-mail: mikhail.vener@gmail.com [Mendeleev University of Chemical Technology, Moscow (Russian Federation); Odinokov, A. V. [Photochemistry Center of the Russian Academy of Sciences, Moscow (Russian Federation); Wehmeyer, C. [Free University, Berlin (Germany); Sebastiani, D. [Martin-Luther-Universität Halle-Wittenberg, Halle (Germany)

    2015-06-07

    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)–glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898–915 (2011)]. These structures are stabilized by the short {sup +}N–H⋯O{sup −} bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm{sup −1}. It is caused by the asymmetric stretching vibrations of the {sup +}N–H⋯O{sup −} fragment. Result of the present paper suggests that infrared spectroscopy in the 2000–2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is

  14. Physical chemistry and evolution of salt tolerance in halobacteria

    Science.gov (United States)

    Lanyi, J. K.

    1980-01-01

    The cellular constituents of extremely halophilic bacteria not only tolerate high salt concentration, but in many cases require it for optical functioning. The characteristics affected by salt include enzyme activity, stability, allosteric regulation, conformation and subunit association. The salt effects are of two major kinds: electrostatic shielding of negative charges by cations at low salt concentration, and hydrophobic stabilization by salting-out type salts at high salt concentration. The composition of halobacterial proteins shows an excess of acidic amino acids and a deficiency of nonpolar amino acids, which accounts for these effects. Since the cohesive forces are weaker and the repulsing forces are stronger in these proteins, preventing aggregation in salt, these structures are no longer suited for functioning in the absence of high salt concentrations. Unlike these nonspecific effects, ribosomes in halobacteria show marked preference for potassium over sodium ions. To ensure the proper intracellular ionic composition, powerful ion transport systems have evolved in the halobacteria, resulting in the extrusion of sodium ions and their replacement by potassium. It is likely that such membrane transport system for ionic movements is a necessary requisite for salt tolerance.

  15. Asymmetric Multilevel Diversity Coding and Asymmetric Gaussian Multiple Descriptions

    CERN Document Server

    Mohajer, Soheil; Diggavi, Suhas N

    2009-01-01

    We consider the asymmetric multilevel diversity (A-MLD) coding problem, where a set of $2^K-1$ information sources, ordered in a decreasing level of importance, is encoded into $K$ messages (or descriptions). There are $2^K-1$ decoders, each of which has access to a non-empty subset of the encoded messages. Each decoder is required to reproduce the information sources up to a certain importance level depending on the combination of descriptions available to it. We obtain a single letter characterization of the achievable rate region for the 3-description problem. In contrast to symmetric multilevel diversity coding, source-separation coding is not sufficient in the asymmetric case, and ideas akin to network coding need to be used strategically. Based on the intuitions gained in treating the A-MLD problem, we derive inner and outer bounds for the rate region of the asymmetric Gaussian multiple description (MD) problem with three descriptions. Both the inner and outer bounds have a similar geometric structure t...

  16. Measurement of Concentrations of Magnesium Ion by Masking Method in Presence of the Interference Lithium Ion in Salt Water System%水盐体系中有干扰Li+离子存在下测定Mg2+浓度的掩蔽法研究

    Institute of Scientific and Technical Information of China (English)

    李红霞; 姚燕; 曾德文

    2012-01-01

    There are abundant lithium ions in salt water system,which lead to serious interference in magnesium measurement by the complexometric titration method with EDTA, making titration results on the high side. In this paper,the authors choose n-butanol and absolute ethylalcohol with the volume ratio of 1:9 as masking agent. What' s more,we discuss the suitable quantity of the mixed alcohol added to the sample under the different Li+/Mg2+ mole ratio, concentrations and sampling volumes. Eventually, this paper indicates that the added quantity of the mixed alcohol has a bigger connection with Li+/Mg2+ mole ratios,but has no obvious connection with the concentrations and the sampling volumes,under the same Li+/Mg2+ mole ratio, the added quantity of the mixed alcohol has a suitable range. The measurement errors for this analytical method could be within 0. 3%. This paper is important to improve reliability and accuracy of the phase chemistry experiment containing lithium ion and magnesium ion in salt water system.%在水盐体系中,大量Li+的存在,对EDTA络合滴定法测镁有严重的干扰,使滴定结果偏高.采用体积比为1∶9的正丁醇与无水乙醇作掩蔽剂,探究其在不同Li+/Mg2+摩尔比、不同浓度、不同取样量下的适宜加入量,得出混合醇的加入量与Li+/Mg2+摩尔比有较大关系,与溶液浓度、取样重的多少均无明显关系;同时指出在同一Li+/Mg2+摩尔比下混合醇的加入量有个适宜的范围.该方法的相对误差不大于0.3%.对提高含Li+和Mg2+的水盐体系相化学实验研究的可靠性和精度具有重要意义.

  17. Modelling asymmetric growth in crowded plant communities

    DEFF Research Database (Denmark)

    Damgaard, Christian

    2010-01-01

    A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size-asymmetric ......A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size...

  18. Cyclodextrins in Asymmetric and Stereospecific Synthesis

    Directory of Open Access Journals (Sweden)

    Fliur Macaev

    2015-09-01

    Full Text Available Since their discovery, cyclodextrins have widely been used as green and easily available alternatives to promoters or catalysts of different chemical reactions in water. This review covers the research and application of cyclodextrins and their derivatives in asymmetric and stereospecific syntheses, with their division into three main groups: (1 cyclodextrins promoting asymmetric and stereospecific catalysis in water; (2 cyclodextrins’ complexes with transition metals as asymmetric and stereospecific catalysts; and (3 cyclodextrins’ non-metallic derivatives as asymmetric and stereospecific catalysts. The scope of this review is to systematize existing information on the contribution of cyclodextrins to asymmetric and stereospecific synthesis and, thus, to facilitate further development in this direction.

  19. The relation between salt and ionic transport coefficients.

    Science.gov (United States)

    Kedem, O; Leaf, A

    1966-03-01

    The reflection coefficient was originally introduced by Staverman to describe the movement of nonelectrolytes through membranes. When this coefficient is extended to salts, one has a choice of defining this term for the whole salt moving as a single electrically neutral component or for the individual ions of the salt. The latter definition is meaningful only in the absence of an electric field across the permeability barrier. This condition may be achieved with the voltage clamp or short-circuit technique and is especially useful in dealing with biological systems in which one rarely has only a single salt or even equal concentrations of the major anion and cation. The relations between the transport coefficients for the salt and its individual ions are derived. The special conditions which may result in negative osmosis through a charged membrane in the presence of a salt are discussed. PMID:5943607

  20. Terahertz metamaterial with asymmetric transmission

    CERN Document Server

    Singh, R; Menzel, C; Rockstuhl, C; Azad, A K; Cheville, R A; Lederer, F; Zhang, W; Zheludev, N I

    2009-01-01

    We show for the first time that a planar metamaterial, an array of coupled metal split-ring resonators with a unit cell lacking mirror symmetry, exhibits asymmetric transmission of terahertz radiation propagating through it in opposite directions. This intriguing effect, that is compatible with Lorentz reciprocity and time-reversal, depends on a directional difference in conversion efficiency of the incident circularly polarized wave into one of opposite handedness, that is only possible in lossy low-symmetry planar chiral metamaterials. We show that asymmetric transmission is linked to excitation of enantiomerically sensitive plasmons, these are induced charge-field excitations that depend on the mutual handedness of incident wave and metamaterial pattern. Various bands of positive, negative and zero phase and group velocities have been identified indicating the opportunity to develop polarization sensitive negative index and slow light media based on such metamaterials.

  1. Stable walking with asymmetric legs

    International Nuclear Information System (INIS)

    Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

  2. Salt effects in electromembrane extraction.

    Science.gov (United States)

    Seip, Knut Fredrik; Jensen, Henrik; Kieu, Thanh Elisabeth; Gjelstad, Astrid; Pedersen-Bjergaard, Stig

    2014-06-20

    Electromembrane extraction (EME) was performed on samples containing substantial amounts of NaCl to investigate how the presence of salts affected the recovery, repeatability, and membrane current in the extraction system. A group of 17 non-polar basic drugs with various physical chemical properties were used as model analytes. When EME was performed in a hollow fiber setup with a supported liquid membrane (SLM) comprised of 2-nitrophenyl octyl ether (NPOE), a substantial reduction in recovery was seen for eight of the substances when 2.5% (w/v) NaCl was present. No correlation between this loss and the physical chemical properties of these substances was seen. The recovery loss was hypothesized to be caused by ion pairing in the SLM, and a mathematical model for the extraction recovery in the presence of salts was made according to the experimental observations. Some variations to the EME system reduced this recovery loss, such as changing the SLM solvent from NPOE to 6-undecanone, or by using a different EME setup with more favorable volume ratios. This was in line with the ion pairing hypothesis and the mathematical model. This thorough investigation of how salts affect EME improves the theoretical understanding of the extraction process, and can contribute to the future development and optimization of the technique. PMID:24792700

  3. High performance of junctionless MOSFET with asymmetric gate

    Science.gov (United States)

    Wang, Ying; Tang, Yan; Sun, Ling-ling; Cao, Fei

    2016-09-01

    In this work, we propose a junctionless MOSFET with asymmetric gates (AG-JL MOSFET). This device is a double gate structure with a lateral offset between the gate, and this leads to different characteristic than a conventional double gate structure. Specifically, the asymmetric gate modulates the effective channel length depending on whether the device is in the ON or OFF state, which this leads to more ideal device characteristics. A comprehensive device performance comparison including the ION/IOFF ratio, subthreshold slope (SS), and drain-induced barrier lowering (DIBL) between the proposed device and a conventional device is presented. The proposed device exhibits superior performance when compared a conventional device, and results show that it is also less sensitive to process variations.

  4. Asymmetric trienamine catalysis: new opportunities in amine catalysis.

    Science.gov (United States)

    Kumar, Indresh; Ramaraju, Panduga; Mir, Nisar A

    2013-02-01

    Amine catalysis, through HOMO-activating enamine and LUMO-activating iminium-ion formation, is receiving increasing attention among other organocatalytic strategies, for the activation of unmodified carbonyl compounds. Particularly, the HOMO-raising activation concept has been applied to the greatest number of asymmetric transformations through enamine, dienamine, and SOMO-activation strategies. Recently, trienamine catalysis, an extension of amine catalysis, has emerged as a powerful tool for synthetic chemists with a novel activation strategy for polyenals/polyenones. In this review article, we discuss the initial developments of trienamine catalysis for highly asymmetric Diels-Alder reactions with different dienophiles and emerging opportunities for other types of cycloadditions and cascade reactions.

  5. Asymmetric information and macroeconomic dynamics

    Science.gov (United States)

    Hawkins, Raymond J.; Aoki, Masanao; Roy Frieden, B.

    2010-09-01

    We show how macroeconomic dynamics can be derived from asymmetric information. As an illustration of the utility of this approach we derive the equilibrium density, non-equilibrium densities and the equation of motion for the response to a demand shock for productivity in a simple economy. Novel consequences of this approach include a natural incorporation of time dependence into macroeconomics and a common information-theoretic basis for economics and other fields seeking to link micro-dynamics and macro-observables.

  6. Entrepreneurship, Asymmetric Information and Unemployment

    OpenAIRE

    Robin Boadway; Nicolas Marceau; Maurice Marchand; Marianne Vigneault

    1998-01-01

    We examine how three sources of asymmetric information affect the supply of entrepreneurs and unemployment. In the first case, banks cannot observe entrepreneurs' risk of failure so ration credit. This increases the number of entrepreneurs and the level of unemployment. In the second case, firms cannot observe workers' effort so offer a wage above the market clearing one. This results in unemployment and too few entrepreneurs. The final case arises when firms cannot observe workers' abilities...

  7. Asymmetric Microscopic Driving Behavior Theory

    OpenAIRE

    Yeo, Hwasoo

    2008-01-01

    Numerous theories on traffic have been developed as traffic congestion gains more and more interest in our daily life. To model traffic phenomena, many traffic theorists have adopted theories from other fields such as fluid mechanics and thermodynamics. However, their efforts to model the traffic at a microscopic level have not been successful yet. Therefore, to overcome the limitations of the existing theories we propose a microscopic asymmetric traffic theory based on analysis of individual...

  8. Nano-LiNiO2 as cathode material for lithium ion battery synthesized by molten salt method%熔融盐法合成锂离子电池正极材料纳米LiNiO2

    Institute of Scientific and Technical Information of China (English)

    白莹; 王蓓; 张伟风

    2011-01-01

    采用熔融盐法,在较低的温度和较短的时间制备了符合理论化学计量比的纳米LiNiO2.研究表明,经过空气中的低温预烧,可以使制备的纯相纳米LiNiO2具有更加优良的结晶性能和更佳的电化学特性.添加预烧步骤前后所得最终产物的初始容量分别为151和148 mAh·g-1,经过100周的循环,容量衰减到55和118 mAh·g-1,容量保持率分别为36.4%和79.7%.原因在于预烧后再进行煅烧降低了阳离子无序度,减少了混杂在Li层中的Ni离子,从而有利于Li离子的扩散,优化了电化学性能.%Molten salt method is applied to synthesis stoichiometric nano-LiNiO2 in rather low temperature and short time. Our results indicate that in the process of preheating the better-crystallized LiNiO2 powder with better electrochemical performances can be produced. The final samples before and after preheating exhibit the initial discharge capacities of 151 and 148 mAh·g-1 respectively. After 100 cycles, they decay to only 55 and 118 mAh·g-1 , with capacity retentions being 36. 4% and 79. 7% respectively. The lowered cation disordering is thought to be favorable for the diffusion of lithium ions, by which the enhanced electrochemial properties can be explained.

  9. NA+/H+ ANTIPORT ACTIVITY IN TONOPLAST VESICLES FROM ROOTS OF THE SALT-TOLERANT PLANTAGO-MARITIMA AND THE SALT-SENSITIVE PLANTAGO-MEDIA

    NARCIS (Netherlands)

    STAAL, M; MAATHUIS, FJM; ELZENGA, JTM; OVERBEEK, JHM; PRINS, HBA

    1991-01-01

    Plantago species differ in their strategy towards salt stress, a major difference being the uptake and distribution of Na+ ions. A salt-sensitive (Plantago media L.) and a salt-tolerant (P. maritima L.) species were compared with respect to Na+/H+ antiport activities at the tonoplast. After exposure

  10. Hybrid materials from organic polymers and inorganic salts

    OpenAIRE

    Köberle, Peter; Laschewsky, André

    2008-01-01

    The prepaparation of amorphous, homogeneous blends of zwitterionic polymers and transition metal salts was investigated. Homogeneous miscibility was achieved in many cases up to equimolar amounts of salt, depending on the anion and cation chosen. Various analytical techniques point to a solid state solution of the inorganic ions in the polymer matrix.

  11. A mean-field theory on the differential capacitance of asymmetric ionic liquid electrolytes

    Science.gov (United States)

    Han, Yining; Huang, Shanghui; Yan, Tianying

    2014-07-01

    The size of ions significantly influences the electric double layer structure of room temperature ionic liquid (IL) electrolytes and their differential capacitance (Cd). In this study, we extended the mean-field theory (MFT) developed independently by Kornyshev (2007J. Phys. Chem. B 111 5545-57) and Kilic, Bazant, and Ajdari (2007 Phys. Rev. E 75 021502) (the KKBA MFT) to take into account the asymmetric 1:1 IL electrolytes by introducing an additional parameter ξ for the anion/cation volume ratio, besides the ionic compressibility γ in the KKBA MFT. The MFT of asymmetric ions becomes KKBA MFT upon ξ = 1, and further reduces to Gouy-Chapman theory in the γ → 0 limit. The result of the extended MFT demonstrates that the asymmetric ILs give rise to an asymmetric Cd, with the higher peak in Cd occurring at positive polarization for the smaller anionic size. At high potential, Cd decays asymptotically toward KKBA MFT characterized by γ for the negative polarization, and characterized by ξγ for the positive polarization, with inverse-square-root behavior. At low potential, around the potential of zero charge, the asymmetric ions cause a higher Cd, which exceeds that of Gouy-Chapman theory.

  12. Salt effects in electromembrane extraction

    DEFF Research Database (Denmark)

    Seip, Knut Fredrik; Jensen, Henrik; Kieu, Thanh Elisabeth;

    2014-01-01

    Electromembrane extraction (EME) was performed on samples containing substantial amounts of NaCl to investigate how the presence of salts affected the recovery, repeatability, and membrane current in the extraction system. A group of 17 non-polar basic drugs with various physical chemical...... properties were used as model analytes. When EME was performed in a hollow fiber setup with a supported liquid membrane (SLM) comprised of 2-nitrophenyl octyl ether (NPOE), a substantial reduction in recovery was seen for eight of the substances when 2.5% (w/v) NaCl was present. No correlation between...... this loss and the physical chemical properties of these substances was seen. The recovery loss was hypothesized to be caused by ion pairing in the SLM, and a mathematical model for the extraction recovery in the presence of salts was made according to the experimental observations. Some variations...

  13. Synthesis, structure, and properties of azatriangulenium salts

    DEFF Research Database (Denmark)

    Laursen, B.W.; Krebs, Frederik C

    2001-01-01

    A general synthetic route to novel nitrogen-bridged heterocyclic carbenium ions of the acridinium and triangulenium type has been developed and investigated. The synthetic method is based on nucleophilic aromatic substitution (SNAr) on the tris(2,6-dimethoxyphenyl)carbenium ion (1) with primary a...... amines and, by virtue of its stepwise and irreversible nature, provides a powerful tool for the preparation of a wide variety of new heterocyclic carbenium salts. Several derivatives of the three new oxygen- and/or nitrogen-bridged triangulenium salts, azadioxa- (6), diazaoxa- (7......), and triazatriangulenium (4), have been synthesized and their physicochemical properties have been investigated. Crystal structures for compounds 2 b-PF6: 2d-PF6, 4b-BF4, 4c-BF4, 6e-BF4, and 8 are reported. The different packing modes found for the triazatriagulenium salts are discussed in relation to the electrostatic...

  14. Fluorescent carbon dot–molecular salt hydrogels

    OpenAIRE

    Cayuela, Angelina; Kennedy, Stuart R.; Soriano, Laura; Jones, Christopher D.; Valcárcel, M.; Steed, Jonathan W.

    2015-01-01

    The incorporation of functionalised carbon nanodots within a novel low molecular weight salt hydrogel derived from 5-aminosalicylic acid is reported. The carbon dots result in markedly enhanced gelation properties, while inclusion within the hydrophobic gel results in a dramatic fluorescence enhancement for the carbon nanomaterials. The resulting hybrid CD gels exhibit a useful sensor response for heavy metal ions, particularly Pb2+.

  15. Ion-binding of glycine zwitterion with inorganic ions in biologically relevant aqueous electrolyte solutions.

    Science.gov (United States)

    Fedotova, Marina V; Kruchinin, Sergey E

    2014-06-01

    The ion-binding between inorganic ions and charged functional groups of glycine zwitter-ion in NaCl(aq), KCl(aq), MgCl2(aq), and CaCl2(aq) has been investigated over a wide salt concentration range by using integral equation theory in the 3D-RISM approach. These systems mimic biological systems where binding of ions to charged residues at protein surfaces is relevant. It has been found that the stability of ion pairs formed by the carboxylate group and added inorganic cations decreases in the sequence Mg(2+)>Ca(2+)>Na(+)>K(+). However, all formed ion pairs are weak and decrease in stability with increasing salt concentration. On the other hand, at a given salt concentration the stability of (-NH3(+):Cl(-))aq ion pairs is similar in all studied systems. The features of ion-binding and the salt concentration effect on this process are discussed.

  16. The behaviour of salt and salt caverns

    NARCIS (Netherlands)

    Fokker, P.A.

    1995-01-01

    Salts are mined for both storage and extraction purposes, either via dry or solution mining techniques. For operational, environmental and geological purposes, it is important to understand and predict the in situ behaviour of salt, in particular the creep and strength characteristics. A micro-mecha

  17. PySALT: SALT science pipeline

    Science.gov (United States)

    Crawford, S. M.; Still, M.; Schellart, P.; Balona, L.; Buckley, D. A. H.; Gulbis, A. A. S.; Kniazev, A.; Kotze, M.; Loaring, N.; Nordsieck, K. H.; Pickering, T. E.; Potter, S.; Romero Colmenero, E.; Vaisanen, P.; Wiliams, T.; Zietsman, E.

    2012-07-01

    The PySALT user package contains the primary reduction and analysis software tools for the SALT telescope. Currently, these tools include basic data reductions for RSS and SALTICAM in both imaging, spectroscopic, and slot modes. Basic analysis software for slot mode data is also provided. These tools are primarily written in python/PyRAF with some additional IRAF code.

  18. A Convenient Method for Asymmetric Reduction of Acetophenone using Lithium Hydroxide

    OpenAIRE

    NISHIKORI, Hisashi; Mizuno, Tomofumi; 錦織, 寿

    2010-01-01

    Optically active lithium-alkoxide catalyzes asymmetric reduction of ketones and imines with alkoxyhydrosilane as a Lewis base. Lithium salt is generally formed by a mixture of optically active alcohol and n-butyllithium as a metal source, which is too sensitive to moisture to handle in air. However, if n-butyllithium is replaced by another lithium source which is stable in air, a more convenient reaction system results. In this study, we examined the enantioselective reduction of acetophenone...

  19. Quantitative Analysis of Soil Salt and Its Main Ions Based on Visible/Near Infrared Spectroscopy in Estuary Area of Yellow River%基于可见/近红外光谱的黄河口区土壤盐分及其主要离子的定量分析

    Institute of Scientific and Technical Information of China (English)

    刘亚秋; 陈红艳; 王瑞燕; 常春艳; 陈哲

    2016-01-01

    Objective]It is crucial to quantitatively and accurately detect saline soil for the prevention of soil salinization and agricultural sustainable development. The objective of this study is to find the characteristic spectra of soil salt and its main ions, and build a quantitative analysis model of soil salinization which is suitable for the estuary area of Yellow River to improve the accuracy and stability of the quantitative analysis. [Method] Kenli County in Shandong Province was selected as the experimental area. Firstly, 96 representative soil samples were collected on October 5th-9th, 2014. After soil sample were dried, the contents of soil salt and ions were analyzed. Then the visible and near infrared reflectance hyperspectra of the soil samples were measured in the laboratory by ASD Fieldspec 3 spectrometer, smoothed and transformed to the first deviation. Secondly, the response spectra of salt and its main ions (Cl-, Na+, Ca2+)were analyzed, first soil salinity and main ions content and the first derivative spectra of reflectance by band correlation analysis, according to the principle of correlation coefficient and significant, their sensitive bands were selected as the characteristic bands, feature bands with maximum correlation coefficient were chosen as the significant feature bands. Then the characteristic spectra which can represent soil salt and main ions (Cl-, Na+, Ca2+) were analyzed synthetically using correlation analysis and identified. Finally, the methods of multiple linear regression (MLR), support vector machine (SVM) and random forest (RF) were used respectively to build quantitative analysis models of soil salinity and ions contents. [Result] The overall shape and trend of the spectra curves of soil salinity and major ions (Cl-, Na+, Ca2+) content in study area were very similar. Soil salinity and major ions (Cl-, Na+, Ca2+) spectra response regions were determined to be 1 320-1 495, 1 790-1 920, 2 120-2 290 nm. On account of the

  20. Salt splitting using ceramic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kurath, D.E. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    Many radioactive aqueous wastes in the DOE complex have high concentrations of sodium that can negatively affect waste treatment and disposal operations. Sodium can decrease the durability of waste forms such as glass and is the primary contributor to large disposal volumes. Waste treatment processes such as cesium ion exchange, sludge washing, and calcination are made less efficient and more expensive because of the high sodium concentrations. Pacific Northwest National Laboratory (PNNL) and Ceramatec Inc. (Salt Lake City UT) are developing an electrochemical salt splitting process based on inorganic ceramic sodium (Na), super-ionic conductor (NaSICON) membranes that shows promise for mitigating the impact of sodium. In this process, the waste is added to the anode compartment, and an electrical potential is applied to the cell. This drives sodium ions through the membrane, but the membrane rejects most other cations (e.g., Sr{sup +2}, Cs{sup +}). The charge balance in the anode compartment is maintained by generating H{sup +} from the electrolysis of water. The charge balance in the cathode is maintained by generating OH{sup {minus}}, either from the electrolysis of water or from oxygen and water using an oxygen cathode. The normal gaseous products of the electrolysis of water are oxygen at the anode and hydrogen at the cathode. Potentially flammable gas mixtures can be prevented by providing adequate volumes of a sweep gas, using an alternative reductant or destruction of the hydrogen as it is generated. As H{sup +} is generated in the anode compartment, the pH drops. The process may be operated with either an alkaline (pH>12) or an acidic anolyte (pH <1). The benefits of salt splitting using ceramic membranes are (1) waste volume reduction and reduced chemical procurement costs by recycling of NaOH; and (2) direct reduction of sodium in process streams, which enhances subsequent operations such as cesium ion exchange, calcination, and vitrification.

  1. Molten salt electrolyte separator

    Science.gov (United States)

    Kaun, Thomas D.

    1996-01-01

    A molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication.

  2. Phase transitions in warm, asymmetric nuclear matter

    International Nuclear Information System (INIS)

    A relativistic mean-field model of nuclear matter with arbitrary proton fraction is studied at finite temperature. An analysis is performed of the liquid-gas phase transition in a system with two conserved charges (baryon number and isospin) using the stability conditions on the free energy, the conservation laws, and Gibbs' criteria for phase equilibrium. For a binary system with two phases, the coexistence surface (binodal) is two dimensional. The Maxwell construction through the phase-separation region is discussed, and it is shown that the stable configuration can be determined uniquely at every density. Moreover, because of the greater dimensionality of the binodal surface, the liquid-gas phase transition is continuous (second order by Ehrenfest's definition), rather than discontinuous (first order), as in familiar one-component systems. Using a mean-field equation of state calibrated to the properties of nuclear matter and finite nuclei, various phase-separation scenarios are considered. The model is then applied to the liquid-gas phase transition that may occur in the warm, dilute matter produced in energetic heavy-ion collisions. In asymmetric matter, instabilities that produce a liquid-gas phase separation arise from fluctuations in the proton concentration (chemical instability), rather than from fluctuations in the baryon density (mechanical instability)

  3. Asymmetric Information and Consumer Demand

    OpenAIRE

    Ismagilova G. N.; Danilina E. I.; Gafurov I. R.; Ismagilov R. I.; Safiullin L. N.

    2014-01-01

    In the paper study the peculiarities of the formation the consumer demand for durable goods, the so-called «experience goods» in markets with asymmetric information. In the known literature sources studying of the demand is based on the assumption that at the moment of the purchase of goods and services people know exactly what price they are willing to pay for them and what utility they are going to obtain using those goods and services. Consider the signal model in which the initial price a...

  4. Spontaneous baryogenesis from asymmetric inflaton

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Yamada, Masaki [Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; DESY Hamburg (Germany)

    2015-10-15

    We propose a variant scenario of spontaneous baryogenesis from asymmetric inflaton based on current-current interactions between the inflaton and matter fields with a non-zero B-L charge. When the inflaton starts to oscillate around the minimum after inflation, it may lead to excitation of a CP-odd component, which induces an effective chemical potential for the B-L number through the current-current interactions. We study concrete inflation models and show that the spontaneous baryogenesis scenario can be naturally implemented in the chaotic inflation in supergravity.

  5. Asymmetric Formal Synthesis of Azadirachtin.

    Science.gov (United States)

    Mori, Naoki; Kitahara, Takeshi; Mori, Kenji; Watanabe, Hidenori

    2015-12-01

    An asymmetric formal synthesis of azadirachtin, a potent insect antifeedant, was accomplished in 30 steps to Ley's synthetic intermediate (longest linear sequence). The synthesis features: 1) rapid access to the optically active right-hand segment starting from the known 5-hydroxymethyl-2-cyclopentenone scaffold; 2) construction of the B and E rings by a key intramolecular tandem radical cyclization; 3) formation of the hemiacetal moiety in the C ring through the α-oxidation of the six-membered lactone followed by methanolysis. PMID:26474211

  6. Transient Stability During Asymmetrical Faults

    OpenAIRE

    Couturier, Nicolas

    2015-01-01

    This research project has been conducted at RTE in order to study the transient stability after asymmetrical faults. When three-phase short-circuits occur in a network, almost all the electrical power is lost on the relevant line(s). Among all short-circuit types, it is the most drastic event and the issue has to be solved very quickly. But oddly, it is also the easiest problem to solve mathematically speaking. This comes from the fact that the system stays balanced, and equations can be simp...

  7. Enhanced Asymmetric Bilinear Model for Face Recognition

    OpenAIRE

    Wenjuan Gong; Weishan Zhang; Jordi Gonzàlez; Yan Ren; Zhen Li

    2015-01-01

    Bilinear models have been successfully applied to separate two factors, for example, pose variances and different identities in face recognition problems. Asymmetric model is a type of bilinear model which models a system in the most concise way. But seldom there are works exploring the applications of asymmetric bilinear model on face recognition problem with illumination changes. In this work, we propose enhanced asymmetric model for illumination-robust face recognition. Instead of initiali...

  8. Interaction modes between asymmetrically and oppositely charged rods

    Science.gov (United States)

    Antila, Hanne S.; Van Tassel, Paul R.; Sammalkorpi, Maria

    2016-02-01

    The interaction of oppositely and asymmetrically charged rods in salt—a simple model of (bio)macromolecular assembly—is observed via simulation to exhibit two free energy minima, separated by a repulsive barrier. In contrast to similar minima in the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the governing mechanism includes electrostatic attraction at large separation, osmotic repulsion at close range, and depletion attraction near contact. A model accounting for ion condensation and excluded volume is shown to be superior to a mean-field treatment in predicting the effect of charge asymmetry on the free-energy profile.

  9. Chiral recognition in salts of trans-1,2-diaminocyclohexane and optically active tartaric acids: crystal structure of 1:2 salt of ( S, S)-diaminocyclohexane with ( R, R)-tartaric acid

    Science.gov (United States)

    Rychlewska, Urszula

    1999-01-01

    X-ray results for the highly organised superstructure (space group P6 522) of the 1:2 salt of (1 S,2 S)-diaminocyclohexane with ( R, R)-tartaric acid ( 1) are compared with the previously reported [1] crystal structures of two diastereomeric 1:1 salts of ( R, R)-diaminocyclohexane with ( R, R)- and ( S, S)-tartaric acid. The asymmetric unit of the unit cell of 1 consists of one molecule of ( S, S)-diaminocyclohexane, one molecule of ( R, R)-hydrogentartrate, half a molecule of ( R, R)-tartaric acid, half of an ( R, R)-tartrate anion, and a water molecule. The presence of all three ionisation states of ( R, R)-tartrate in one crystal is most unusual, as is the anti conformation of the carboxyl group in ( R, R)-tartaric acid. Association of ( S, S)-diaminocyclohexane and ( R, R)-hydrogentartrate involves three-centre hydrogen bonds between ammonium groups as donors and α-hydroxycarboxylate and α-hydroxycarboxyl moieties as acceptors. The remaining hydrogen bonds stabilise this motif and expand it to three dimensions. The results provide some insights into the enantioselective association of trans-1,2-diaminocyclohexane with optically active tartaric acids, the main driving force being the hydrogen bonding. While in a homochiral 1:1 salt the two ions combine by a scissors-shaped hydrogen bonding motif formed by two ammonium functions as donors and vicinal hydroxyl groups as acceptors, in heterochiral salts the cation and anion species join together via three-centre hydrogen bonds between ammonium functions and planar or nearly planar α-hydroxycarboxylate moieties.

  10. Low-salt diet

    Science.gov (United States)

    ... Some have a lot of salt in them. Home water softeners add salt to water. If you have one, limit how much tap water you drink. Drink bottled water instead. Ask your doctor if a salt substitute is safe for you. Many contain a lot ...

  11. Ion mobility sensor system

    Science.gov (United States)

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  12. Genotypic Differences in Antioxidative Stress and Salt Tolerance of Three Poplars Under Salt Stress

    Institute of Scientific and Technical Information of China (English)

    Wang Ruigang; Chen Shaoliang; Ma Haiyuan; Liu Liyuan; Li He; Weng Haijiao; Hao Zhiyong; Yang Shuang

    2006-01-01

    To evaluate genotypic difference in antioxidative ability and salt tolerance in poplars,the authors investigated the effects of increasing content of soil NaC1 on salt concentration in leaves,superoxide dismutase (SOD) and peroxidase (POD) activities,malondialdehyde (MDA)content,and membrane permeability (MP) in Populus euphratica Oliv.,P.popularis"35-44,"and P.×euramericana cv.I-214 (hereafter abbreviated as P.cv.I-214).Na+and C1- concentrations in leaves of P.popularis increased markedly over the increase of the duration of exposure to salinity,and culminated after 28 days of salt stress.SOD and POD activities declined correspondingly,followed by significant increases of MDA and MP,and leaf injury was finally observed.Compared with P.popularis,leaf Na+and C1- in P.cv.I-214 exhibited a trend similar to P.popularis,but a lower salt-induced increase of MDA and permeability was observed and lighter leaf necrosis occurred.In contrast to P.popularis and P.cv.I-214,SOD and POD activities in P.euphratica leaves increased rapidiy at the beginning of salt stress with a light soil NaCl concentration of 58.5 mmol/L.Furthermore,salt ion concentration,MDAcontent,and MP in P.euphratica leaves did not increase significantly during 28 days of increasing salt stress.Therefore,the increase in MP in P.popularis and P.cv.I-214 had a close relationship with a salt buildup in leaves under increasing salt stress.Salt-induced declines of SOD and POD activities might accelerate lipid peroxide and consequently resulted in ion leakage.P.euphratica rapidly activated antioxidant enzymes after the onset of salt stress,which might reduce the accumulation of reactive oxygen species and the subsequent acceleration of lipid peroxide.P.euphratica leaves exhibited a higher capacity to exclude salt in a longer period of increasing salinity,thus limited salt-induced lipid peroxide and MP,which contributed to membrane integrity maintenance and salt tolerance of P.euphratica.

  13. 咸水冰融化与土壤入渗过程不同盐分离子迁移规律研究%Study on Migration of Different Salt Ions in Melting and Infiltration Processes of Saline Water Ice

    Institute of Scientific and Technical Information of China (English)

    潘洁; 肖辉; 王立艳; 程文娟; 陆文龙

    2012-01-01

    Simulation and field experiments were conducted to investigate the migration of different salt ions in melting and infiltration processes of saline water ice. The aim of these experiments is to reveal the mechanism of water quality changes in ice melting and the distribution of different ions in different soil depth. The results showed that the content of all salt ions decreased rapidly during ice melting process. However,different ions leached in different rate. The sequence of different ions leaching ratio from high to low was Cl > Mg2+ > K + > Na+ > SP42- > Ca2+ > HCO3 . The difference of ions leaching rate leaded to changes of ions composition in melted water, which reduced sodium adsorption ratio and increased water pH eventually. After irrigation with freezing saline water,all salt ions of soil(0 ~ 80 cm) were decreased except HCO3 , which increased by 6. 85%. The sequence of ions leaching ratio from high to low was Mg2+ > Cl- > Ca2+ > Na+ > K+ > SO42- > HCO3- . Although the leaching ratios of Cl" and Na+ were not the highest, their proportions reached 62. 01 % and 21. 96% in total leaching salt,respectively. Irrigation with freezing saline water changed the ion composition of soil and resulted in alkaline trend in the surface soil. Therefore,freezing irrigation with saline water should be assorted with some measures to prevent soil alkalization.%通过模拟试验及大田试验研究了咸水冰融化过程及土壤入渗过程不同盐分离子迁移分布规律,以期揭示咸水冰融水水质变化机理及咸水结冰灌溉对土壤盐分分布的影响.试验结果表明,咸水冰融化过程各离子含量均急速下降,但不同离子融出速度不同,各离子融出比例高低次序为Cl- >Mg2 >K+ >Na+ >SO4- >Ca2+ >HCO3-;离子融出速度的不同,导致融水离子组成发生变化,最终使融水钠吸附比下降,pH值上升.咸水结冰灌溉使0~ 80 cm土体中除HCO3-增加6.85%以外,其余各

  14. Excitons in asymmetric quantum wells

    Science.gov (United States)

    Grigoryev, P. S.; Kurdyubov, A. S.; Kuznetsova, M. S.; Ignatiev, I. V.; Efimov, Yu. P.; Eliseev, S. A.; Petrov, V. V.; Lovtcius, V. A.; Shapochkin, P. Yu.

    2016-09-01

    Resonance dielectric response of excitons is studied for the high-quality InGaAs/GaAs heterostructures with wide asymmetric quantum wells (QWs). To highlight effects of the QW asymmetry, we have grown and studied several heterostructures with nominally square QWs as well as with triangle-like QWs. Several quantum confined exciton states are experimentally observed as narrow exciton resonances. A standard approach for the phenomenological analysis of the profiles is generalized by introducing different phase shifts for the light waves reflected from the QWs at different exciton resonances. Good agreement of the phenomenological fit to the experimentally observed exciton spectra for high-quality structures allowed us to reliably obtain parameters of the exciton resonances: the exciton transition energies, the radiative broadenings, and the phase shifts. A direct numerical solution of the Schrödinger equation for the heavy-hole excitons in asymmetric QWs is used for microscopic modeling of the exciton resonances. Remarkable agreement with the experiment is achieved when the effect of indium segregation is taken into account. The segregation results in a modification of the potential profile, in particular, in an asymmetry of the nominally square QWs.

  15. Asymmetric Laguerre-Gaussian beams

    Science.gov (United States)

    Kovalev, A. A.; Kotlyar, V. V.; Porfirev, A. P.

    2016-06-01

    We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redistributed toward peripheral diffraction rings. The projection of the orbital angular momentum (OAM) onto the optical axis is calculated. The OAM is shown to grow quadratically with increasing asymmetry parameter of the aLG beam, which equals the ratio of the shift to the waist radius. Conditions for the OAM becoming equal to the topological charge have been derived. For aLG beams with zero radial index, we have deduced an expression to define the intensity maximum coordinates and shown the crescent-shaped intensity pattern to rotate during propagation. Results of the experimental generation and rotation of aLG beams agree well with theoretical predictions.

  16. Some Remarks on Asymmetric Syntheses from Recent Studies

    OpenAIRE

    Baba, Naomichi

    1990-01-01

    Some asymmetric syntheses were presented here and discussed briefly including NADH model reactions, phase transfer-catalyzed asymmetric epoxidation, enantiotopic group-selective hydrolysis of a malonic anhydride with alkoxide anion, intramolecular acid-catalyzed lactonizations, catalytic asymmetric Diels-Alder synthesis, asymmetric aldol condensation, chiral homoallyl alcohol synthesis, asymmetric addition of diethylzinc to aldehyde, kinetic resolution of racemic hydroperoxides and binaphthol...

  17. Research on Influence Laws of Different Salt Content and Ion Content to Boundary Moisture Content of Soil%不同含盐量及离子含量对土的界限含水率的影响规律研究

    Institute of Scientific and Technical Information of China (English)

    努尔比亚·吾斯曼; 何建新; 苏枋

    2012-01-01

    The influence laws of the total salt content and different ion content(sulfate and chlorine salt) in fine-grained soil to the boundary moisture content of the soil are studied here in detail.Through artificially making the soil samples with different salt content and ion content,the boundary moisture content of the soil is determined,and the influence of salt content on the boundary moisture content of the soil is studied by using projection pursuit regression analysis method.It is found by analysis that when adding sodium chloride,the hydraulic limit and plastic limit of the soil are decreased with salt content increasing,and when adding sodium sulfate,the hydraulic limit and plastic limit of the soil are risen with salt content increasing.At the same time,when size changing,there appears expand phenomenon.When adding each half of the sodium chloride and sodium sulfate,the hydraulic limit of the soil is dropped obviously,and the plastic limit of the soil is changed a little with salt content increasing.%土中含盐量影响土的物理力学性能,研究细粒土中总盐含量及不同离子含量(硫酸盐和氯盐)对认识土的界限含水率的影响规律有重要意义。人工配制不同含盐量、不同离子含量的土样,测定土的界限含水率,并运用投影寻踪回归分析方法研究含盐量对土的界限含水率的影响。研究结果表明:加氯化钠时,随着含盐量的增加,土的液、塑限均有下降;加硫酸钠时,随着含盐量的增加,土的液、塑限均有上升,体积发生变化,出现膨胀现象;各加一半时,随着含盐量的增加,土的液限明显下降,塑限变化不大。

  18. A molecular simulation study on salt response of polyelectrolyte complexes

    Science.gov (United States)

    Antila, Hanne; van Tassel, Paul; Sammalkorpi, Maria

    2015-03-01

    In aqueous solutions, oppositely charged polymers, polyelectrolytes (PEs) form complexes which are known to be sensitive to added salt with responses ranging from shrinking to full destabilization of the complex. As a specific application of PE complexes, the complex formation of DNA with polycations has been demonstrated to be an effective means of transfecting genetic material in gene therapy. We use all-atom molecular dynamics and coarse-grained Monte Carlo simulations to investigate the effect of excess salt on DNA-polycation complex stability. The detailed all-atom simulations demonstrate the mechanism of polycation and ion species specific salt-driven dissociation involving charge reversal. More generally, other possible mechanisms of salt driven dissociation exist as well. The coarse grained approach, which describes the PE complex as oppositely charged, rigid rods and ions as hard spheres, provides a more complete understanding of PE interactions in salt, and suggests possible mechanisms leading to repulsion between the oppositely charged polyelectrolytes.

  19. Effects of Salt Stress on Three Ecologically Distinct Plantago Species.

    Science.gov (United States)

    Al Hassan, Mohamad; Pacurar, Andrea; López-Gresa, María P; Donat-Torres, María P; Llinares, Josep V; Boscaiu, Monica; Vicente, Oscar

    2016-01-01

    Comparative studies on the responses to salt stress of taxonomically related taxa should help to elucidate relevant mechanisms of stress tolerance in plants. We have applied this strategy to three Plantago species adapted to different natural habitats, P. crassifolia and P. coronopus-both halophytes-and P. major, considered as salt-sensitive since it is never found in natural saline habitats. Growth inhibition measurements in controlled salt treatments indicated, however, that P. major is quite resistant to salt stress, although less than its halophytic congeners. The contents of monovalent ions and specific osmolytes were determined in plant leaves after four-week salt treatments. Salt-treated plants of the three taxa accumulated Na+ and Cl- in response to increasing external NaCl concentrations, to a lesser extent in P. major than in the halophytes; the latter species also showed higher ion contents in the non-stressed plants. In the halophytes, K+ concentration decreased at moderate salinity levels, to increase again under high salt conditions, whereas in P. major K+ contents were reduced only above 400 mM NaCl. Sorbitol contents augmented in all plants, roughly in parallel with increasing salinity, but the relative increments and the absolute values reached did not differ much in the three taxa. On the contrary, a strong (relative) accumulation of proline in response to high salt concentrations (600-800 mM NaCl) was observed in the halophytes, but not in P. major. These results indicate that the responses to salt stress triggered specifically in the halophytes, and therefore the most relevant for tolerance in the genus Plantago are: a higher efficiency in the transport of toxic ions to the leaves, the capacity to use inorganic ions as osmotica, even under low salinity conditions, and the activation, in response to very high salt concentrations, of proline accumulation and K+ transport to the leaves of the plants. PMID:27490924

  20. Lithium Titanate Confined in Carbon Nanopores for Asymmetric Supercapacitors.

    Science.gov (United States)

    Zhao, Enbo; Qin, Chuanli; Jung, Hong-Ryun; Berdichevsky, Gene; Nese, Alper; Marder, Seth; Yushin, Gleb

    2016-04-26

    Porous carbons suffer from low specific capacitance, while intercalation-type active materials suffer from limited rate when used in asymmetric supercapacitors. We demonstrate that nanoconfinement of intercalation-type lithium titanate (Li4Ti5O12) nanoparticles in carbon nanopores yielded nanocomposite materials that offer both high ion storage density and rapid ion transport through open and interconnected pore channels. The use of titanate increased both the gravimetric and volumetric capacity of porous carbons by more than an order of magnitude. High electrical conductivity of carbon and the small size of titanate crystals allowed the composite electrodes to achieve characteristic charge and discharge times comparable to that of the electric double-layer capacitors. The proposed composite synthesis methodology is simple, scalable, and applicable for a broad range of active intercalation materials, while the produced composite powders are compatible with commercial electrode fabrication processes. PMID:26950509

  1. Condensation on Slippery Asymmetric Bumps

    CERN Document Server

    Park, Kyoo-Chul; He, Neil; Aizenberg, Joanna

    2015-01-01

    Bumps are omnipresent from human skin to the geological structures on planets, which offer distinct advantages in numerous phenomena including structural color, drag reduction, and extreme wettability. Although the topographical parameters of bumps such as radius of curvature of convex regions significantly influence various phenomena including anti-reflective structures and contact time of impacting droplets, the effect of the detailed bump topography on growth and transport of condensates have not been clearly understood. Inspired by the millimetric bumps of the Namib Desert beetle, here we report the identified role of radius of curvature and width of bumps with homogeneous surface wettability in growth rate, coalescence and transport of water droplets. Further rational design of asymmetric convex topography and synergetic combination with slippery coating simultaneously enable self-transport, leading to unseen five-fold higher growth rate and an order of magnitude faster shedding time of droplets compared...

  2. New asymmetric quantum codes over Fq

    Science.gov (United States)

    Ma, Yuena; Feng, Xiaoyi; Xu, Gen

    2016-07-01

    Two families of new asymmetric quantum codes are constructed in this paper. The first family is the asymmetric quantum codes with length n=qm-1 over Fq, where qge 5 is a prime power. The second one is the asymmetric quantum codes with length n=3m-1. These asymmetric quantum codes are derived from the CSS construction and pairs of nested BCH codes. Moreover, let the defining set T1=T2^{-q}, then the real Z-distance of our asymmetric quantum codes are much larger than δ _max+1, where δ _max is the maximal designed distance of dual-containing narrow-sense BCH code, and the parameters presented here have better than the ones available in the literature.

  3. SALT Science Conference 2015

    Science.gov (United States)

    Buckley, David; Schroeder, Anja

    The Southern African Large Telescope (SALT) has seen great changes in the last years following the beginning of full time science operations in 2011. The three first generation instruments, namely the SALTICAM imager, the Robert Stobie Spectrograph (RSS) and its multiple modes and finally in 2014, the new High Resolution Spectrograph (HRS), have commissioned it. The SALT community now eagerly anticipate the installation and commissioning of the near-infrared arm of RSS, likely to commence in 2016. The the third "Science with SALT" conference was held at the Stellenbosch Institute of Advanced Study from 1-5 June 2015. The goals of this conference were to: -Present and discuss recent results from SALT observations; -Anticipate scientific programs that will be carried out with new SALT instrumentation such as RSS-NIR; -Provide a scientific environment in which to foster inter-institutional and inter-facility collaborations between scientists at the different SALT partners; -Provide an opportunity for students and postdocs to become more engaged in SALT science and operations; -Encourage the scientific strategic planning that will be necessary to insure an important role for SALT in an era of large astronomical facilities in the southern hemisphere such as MeerKAT, the SKA, LSST, and ALMA; -Consider options for future instrumentation and technical development of SALT; and, -Present, discuss, and engage in the SALT Collateral Benefits program led by SAAO. Conference proceedings editors: David Buckley and Anja Schroeder

  4. Leaf sodium accumulation facilitates salt stress adaptation and preserves photosystem functionality in salt stressed Ocimum basilicum

    NARCIS (Netherlands)

    Mancarella, S.; Orsini, F.; Oosten, van M.J.; Sanoubar, R.; Stanghellini, C.; Kondo, S.; Gianquinto, G.; Maggio, A.

    2016-01-01

    In this study, plant growth, water relations, ABA levels, ion accumulation patterns and chlorophyll fluorescence were functionally linked to salt stress tolerance of two basil cultivars (Napoletano and Genovese) with different stress sensitivity levels. Plants were treated with salty water at 0,

  5. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder; Bruus, Henrik

    2014-01-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in ...

  6. Salinity tolerance in plants. Quantitative approach to ion transport starting from halophytes and stepping to genetic and protein engineering for manipulating ion fluxes

    OpenAIRE

    Volkov, Vadim

    2015-01-01

    Ion transport is the fundamental factor determining salinity tolerance in plants. The Review starts from differences in ion transport between salt tolerant halophytes and salt-sensitive plants with an emphasis on transport of potassium and sodium via plasma membranes. The comparison provides introductory information for increasing salinity tolerance. Effects of salt stress on ion transport properties of membranes show huge opportunities for manipulating ion fluxes. Further steps require knowl...

  7. Determination of heat stable salt anions in alkanolamine desulphurization solution by ion chromatography%离子色谱法测定醇胺脱硫溶液中热稳定盐

    Institute of Scientific and Technical Information of China (English)

    唐飞; 汪玉洁; 罗勤; 唐蒙; 陈赓良

    2012-01-01

    为了控制热稳定盐(HSS)对天然气净化装置造成的危害,建立了一种同时检测醇胺脱硫溶液中的乙酸根离子、甲酸根离子、氯离子、硫酸根离子、草酸根离子、硫代硫酸根离子和硫氰酸根离子的离子色谱方法.该方法利用膜过滤、反相固相萃取和稀释3个步骤对工业样品进行前处理,采用氢氧化钾梯度淋洗和电导检测的方式,实现了7种离子的分离与检测.方法的线性范围为0.01~0.5mmol/L,检出限(以信噪比(S/N)为3计)小于0.1 mg/L,回收率为80.0%~100.3%.在5个不同添加浓度下分别测定了上述7个离子,色谱峰面积的重复性良好(相对标准偏差(RSD,n=10)为0.94%~3.99%.通过3个实验室比对试验,表明该方法再现性良好,色谱峰面积的RSD小于5%.应用该方法成功地检测了8家天然气净化厂、3家石油炼厂和1家煤制油工厂的脱硫溶液样品中的HSS,并连续监测某天然气净化装置15 d.该方法具有良好的可靠性和实用性.%To control the potential risk of natural gas purification plants, an Ion chromato-graphic method has been developed to determine the heat stable salts (HSS) in alkanolamine desulphurization solution. Seven HSS anions, including CH3COO-, HCOO-, Cl-, SO2-4, C2O2-4, S2O2-3, SCN-, were determined in a single injection. Before the chromatographic analysis , these industrial samples were pie treated by three steps, i. e. filtration, solid phase extraction and dilution. Using the gradient elution with KOH solution, all of the seven anions have been separated and determined by a conductivity detector. As the calibration results, the linear range of this method was 0. 01 - 0. 5 mmol/L for the 7 anions. The limit of detection ( LOD, S/ N =3) was 0.1 mg/L for each anion. By spiked standard solutions in the samples, the recoveries were in the range of 80. 0% - 100. 3%. The repeatability of this method was evaluated at five different concentrations. The relative

  8. Ion-mediated interactions between net-neutral slabs: Weak and strong disorder effects

    Science.gov (United States)

    Ghodrat, Malihe; Naji, Ali; Komaie-Moghaddam, Haniyeh; Podgornik, Rudolf

    2015-12-01

    We investigate the effective interaction between two randomly charged but otherwise net-neutral, planar dielectric slabs immersed in an asymmetric Coulomb fluid containing a mixture of mobile monovalent and multivalent ions. The presence of charge disorder on the apposed bounding surfaces of the slabs leads to substantial qualitative changes in the way they interact, as compared with the standard picture provided by the van der Waals and image-induced, ion-depletion interactions. While, the latter predict purely attractive interactions between strictly neutral slabs, we show that the combined effects from surface charge disorder, image depletion, Debye (or salt) screening, and also, in particular, their coupling with multivalent ions, give rise to a more diverse behavior for the effective interaction between net-neutral slabs at nano-scale separations. Disorder effects show large variation depending on the properly quantified strength of disorder, leading either to non-monotonic effective interaction with both repulsive and attractive branches when the surface charges are weakly disordered (small disorder variance) or to a dominating attractive interaction that is larger both in its range and magnitude than what is predicted from the van der Waals and image-induced, ion-depletion interactions, when the surfaces are strongly disordered (large disorder variance).

  9. Regenerating a symmetry in asymmetric dark matter.

    Science.gov (United States)

    Buckley, Matthew R; Profumo, Stefano

    2012-01-01

    Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe. PMID:22304253

  10. Asymmetric dark matter in braneworld cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, Michael T.; Whittingham, Ian B., E-mail: Michael.Meehan@my.jcu.edu.au, E-mail: Ian.Whittingham@jcu.edu.au [School of Engineering and Physical Sciences, James Cook University, Townsville, 4811 Australia (Australia)

    2014-06-01

    We investigate the effect of a braneworld expansion era on the relic density of asymmetric dark matter. We find that the enhanced expansion rate in the early universe predicted by the Randall-Sundrum II (RSII) model leads to earlier particle freeze-out and an enhanced relic density. This effect has been observed previously by Okada and Seto (2004) for symmetric dark matter models and here we extend their results to the case of asymmetric dark matter. We also discuss the enhanced asymmetric annihilation rate in the braneworld scenario and its implications for indirect detection experiments.

  11. Regenerating a symmetry in asymmetric dark matter.

    Science.gov (United States)

    Buckley, Matthew R; Profumo, Stefano

    2012-01-01

    Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe.

  12. Asymmetric Dark Matter and Effective Operators

    CERN Document Server

    Buckley, Matthew R

    2011-01-01

    In order to annihilate in the early Universe to levels well below the measured dark matter density, asymmetric dark matter must possess large couplings to the Standard Model. In this paper, we consider effective operators which allow asymmetric dark matter to annihilate into quarks. In addition to a bound from requiring sufficient annihilation, the energy scale of such operators can be constrained by limits from direct detection and monojet searches at colliders. We show that the allowed parameter space for these operators is highly constrained, leading to non-trivial requirements that any model of asymmetric dark matter must satisfy.

  13. Salt Weathering on Mars

    Science.gov (United States)

    Jagoutz, E.

    2006-12-01

    Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974

  14. Construction of thermionic alkali-ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Ul Haq, F.

    1986-04-01

    A simple technique is described by which singly charged alkali ions of K, Na, Li, Rb and Cs are produced by heating ultra-pure chemical salts of different alkali metals on tungsten filaments without employing a temperature measuring device. The character of alkali-ion currents at different heating powers and the remarkably constant ion emission current for prolonged periods are discussed.

  15. Asymmetric plasmonic induced ionic noise in metallic nanopores

    Science.gov (United States)

    Li, Yi; Chen, Chang; Willems, Kherim; Lagae, Liesbet; Groeseneken, Guido; Stakenborg, Tim; van Dorpe, Pol

    2016-06-01

    We present distinct asymmetric plasmon-induced noise properties of ionic transport observed through gold coated nanopores. We thoroughly investigated the effects of bias voltage and laser illumination. We show that the potential drop across top-coated silicon nanocavity pores can give rise to a large noise asymmetry (~2-3 orders of magnitude). Varying the bias voltage has an appreciable effect on the noise density spectra, typically in the Lorentzian components. The laser power is found to strongly affect the ionic noise level as well as the voltage threshold for light-induced noise generation. The asymmetric noise phenomenon is attributed to plasmon-induced interfacial reactions which promote light-induced charge fluctuation in the ion flow and allow voltage modulation of photo-induced carriers surmounting over such Schottky junctions. We further compare the ionic noise performances of gold nanocavities containing different material stacks, among which thermal oxide passivation of the silicon successfully mitigates the light-induced noise and is also fully CMOS-compatible. The understanding of the described noise characteristics will help to foster multiple applications using related structures including plasmonic-based sensing or plasmon-induced catalysis such as water splitting or solar energy conversion devices.We present distinct asymmetric plasmon-induced noise properties of ionic transport observed through gold coated nanopores. We thoroughly investigated the effects of bias voltage and laser illumination. We show that the potential drop across top-coated silicon nanocavity pores can give rise to a large noise asymmetry (~2-3 orders of magnitude). Varying the bias voltage has an appreciable effect on the noise density spectra, typically in the Lorentzian components. The laser power is found to strongly affect the ionic noise level as well as the voltage threshold for light-induced noise generation. The asymmetric noise phenomenon is attributed to plasmon

  16. Twin Higgs Asymmetric Dark Matter.

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.

  17. Why Do Nucleosomes Unwrap Asymmetrically?

    Science.gov (United States)

    de Bruin, Lennart; Tompitak, Marco; Eslami-Mossallam, Behrouz; Schiessel, Helmut

    2016-07-01

    Nucleosomes, DNA spools with a protein core, engage about three-quarters of eukaryotic DNA and play a critical role in chromosomal processes, ranging from gene regulation, recombination, and replication to chromosome condensation. For more than a decade, micromanipulation experiments where nucleosomes are put under tension, as well as the theoretical interpretations of these experiments, have deepened our understanding of the stability and dynamics of nucleosomes. Here we give a theoretical explanation for a surprising new experimental finding: nucleosomes wrapped onto the 601 positioning sequence (the sequence used in most laboratories) respond highly asymmetrically to external forces by always unwrapping from the same end. Using a computational nucleosome model, we show that this asymmetry can be explained by differences in the DNA mechanics of two very short stretches on the wrapped DNA portion. Our finding suggests that the physical properties of nucleosomes, here the response to forces, can be tuned locally by the choice of the underlying base-pair sequence. This leads to a new view of nucleosomes: a physically highly varied set of DNA-protein complexes whose properties can be tuned on evolutionary time scales to their specific function in the genomic context. PMID:26991771

  18. Twin Higgs Asymmetric Dark Matter

    CERN Document Server

    García, Isabel García; March-Russell, John

    2015-01-01

    We study Asymmetric Dark Matter (ADM) in the context of the minimal (Fraternal) Twin Higgs solution to the little hierarchy problem, with a twin sector with gauged $SU(3)' \\times SU(2)'$, a twin Higgs, and only third generation twin fermions. Naturalness requires the QCD$^\\prime$ scale $\\Lambda'_{\\rm QCD} \\simeq 0.5 - 20 \\ {\\rm GeV}$, and $t'$ to be heavy. We focus on the light $b'$ quark regime, $m_{b'} \\lesssim \\Lambda'_{\\rm QCD}$, where QCD$^\\prime$ is characterised by a single scale $\\Lambda'_{\\rm QCD}$ with no light pions. A twin baryon number asymmetry leads to a successful DM candidate: the spin-3/2 twin baryon, $\\Delta' \\sim b'b'b'$, with a dynamically determined mass ($\\sim 5 \\Lambda'_{\\rm QCD}$) in the preferred range for the DM-to-baryon ratio $\\Omega_{\\rm DM}/\\Omega_{\\rm baryon} \\simeq 5$. Gauging the $U(1)'$ group leads to twin atoms ($\\Delta'$ - $\\bar {\\tau'}$ bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo ...

  19. Asymmetric total synthesis of vindoline.

    Science.gov (United States)

    Kato, Daisuke; Sasaki, Yoshikazu; Boger, Dale L

    2010-03-24

    A concise asymmetric total synthesis of (-)-vindoline (1) is detailed based on a tandem intramolecular [4+2]/[3+2] cycloaddition cascade of a 1,3,4-oxadiazole inspired by the natural product structure, in which the tether linking the initiating dienophile and oxadiazole bears a chiral substituent that controls the facial selectivity of the initiating Diels-Alder reaction and sets absolute stereochemistry of the remaining six stereocenters in the cascade cycloadduct. This key reaction introduces three rings and four C-C bonds central to the pentacyclic ring system setting all six stereocenters and introducing essentially all the functionality found in the natural product in a single step. Implementation of the approach also required the development of a unique ring expansion reaction to provide a six-membered ring suitably functionalized for introduction of the Delta (6, 7)-double bond found in the core structure of vindoline and defined our use of a protected hydroxymethyl group as the substituent used to control the stereochemical course of the cycloaddition cascade.

  20. Chaos suppression through asymmetric coupling

    Science.gov (United States)

    Bragard, J.; Vidal, G.; Mancini, H.; Mendoza, C.; Boccaletti, S.

    2007-12-01

    We study pairs of identical coupled chaotic oscillators. In particular, we have used Roessler (in the funnel and no funnel regimes), Lorenz, and four-dimensional chaotic Lotka-Volterra models. In all four of these cases, a pair of identical oscillators is asymmetrically coupled. The main result of the numerical simulations is that in all cases, specific values of coupling strength and asymmetry exist that render the two oscillators periodic and synchronized. The values of the coupling strength for which this phenomenon occurs is well below the previously known value for complete synchronization. We have found that this behavior exists for all the chaotic oscillators that we have used in the analysis. We postulate that this behavior is presumably generic to all chaotic oscillators. In order to complete the study, we have tested the robustness of this phenomenon of chaos suppression versus the addition of some Gaussian noise. We found that chaos suppression is robust for the addition of finite noise level. Finally, we propose some extension to this research.

  1. Force on an Asymmetric Capacitor

    CERN Document Server

    Bahder, T B; Bahder, Thomas B.; Fazi, Chris

    2002-01-01

    When a high voltage (~30 kV) is applied to a capacitor whose electrodes have different physical dimensions, the capacitor experiences a net force toward the smaller electrode (Biefeld-Brown effect). We have verified this effect by building four capacitors of different shapes. The effect may have applications to vehicle propulsion and dielectric pumps. We review the history of this effect briefly through the history of patents by Thomas Townsend Brown. At present, the physical basis for the Biefeld-Brown effect is not understood. The order of magnitude of the net force on the asymmetric capacitor is estimated assuming two different mechanisms of charge conduction between its electrodes: ballistic ionic wind and ionic drift. The calculations indicate that ionic wind is at least three orders of magnitude too small to explain the magnitude of the observed force on the capacitor. The ionic drift transport assumption leads to the correct order of magnitude for the force, however, it is difficult to see how ionic dr...

  2. Twin Higgs Asymmetric Dark Matter.

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors. PMID:26430985

  3. Modeling of asymmetrical boost converters

    Directory of Open Access Journals (Sweden)

    Eliana Isabel Arango Zuluaga

    2014-03-01

    Full Text Available The asymmetrical interleaved dual boost (AIDB is a fifth-order DC/DC converter designed to interface photovoltaic (PV panels. The AIDB produces small current harmonics to the PV panels, reducing the power losses caused by the converter operation. Moreover, the AIDB provides a large voltage conversion ratio, which is required to step-up the PV voltage to the large dc-link voltage used in grid-connected inverters. To reject irradiance and load disturbances, the AIDB must be operated in a closed-loop and a dynamic model is required. Given that the AIDB converter operates in Discontinuous Conduction Mode (DCM, classical modeling approaches based on Continuous Conduction Mode (CCM are not valid. Moreover, classical DCM modeling techniques are not suitable for the AIDB converter. Therefore, this paper develops a novel mathematical model for the AIDB converter, which is suitable for control-pur-poses. The proposed model is based on the calculation of a diode current that is typically disregarded. Moreover, because the traditional correction to the second duty cycle reported in literature is not effective, a new equation is designed. The model accuracy is contrasted with circuital simulations in time and frequency domains, obtaining satisfactory results. Finally, the usefulness of the model in control applications is illustrated with an application example.

  4. Hydroxycarboxylic acids and salts

    Energy Technology Data Exchange (ETDEWEB)

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  5. SALT for Language Acquisition.

    Science.gov (United States)

    Bancroft, W. Jane

    1996-01-01

    Discusses Schuster's Suggestive-Accelerative Learning Techniques (SALT) Method, which combines Lozanov's Suggestopedia with such American methods as Asher's Total Physical Response and Galyean's Confluent Education. The article argues that students trained with the SALT Method have higher achievement scores and better attitudes than others. (14…

  6. Plasma and Energetic Particle Behaviors During Asymmetric Magnetic Reconnection at the Magnetopause

    Science.gov (United States)

    Lee, S. H.; Zhang, H.; Zong, Q.-G.; Otto, A.; Sibeck, D. G.; Wang, Y.; Glassmeier, K.-H.; Daly, P.W.; Reme, H.

    2014-01-01

    The factors controlling asymmetric reconnection and the role of the cold plasma population in the reconnection process are two outstanding questions. We present a case study of multipoint Cluster observations demonstrating that the separatrix and flow boundary angles are greater on the magnetosheath than on the magnetospheric side of the magnetopause, probably due to the stronger density than magnetic field asymmetry at this boundary. The motion of cold plasmaspheric ions entering the reconnection region differs from that of warmer magnetosheath and magnetospheric ions. In contrast to the warmer ions, which are probably accelerated by reconnection in the diffusion region near the subsolar magnetopause, the colder ions are simply entrained by ??×?? drifts at high latitudes on the recently reconnected magnetic field lines. This indicates that plasmaspheric ions can sometimes play only a very limited role in asymmetric reconnection, in contrast to previous simulation studies. Three cold ion populations (probably H+, He+, and O+) appear in the energy spectrum, consistent with ion acceleration to a common velocity.

  7. Geomechanics of bedded salt

    Energy Technology Data Exchange (ETDEWEB)

    Serata, S.; Milnor, S.W.

    1979-06-08

    Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temperature is considered. Findings on the permeability of salt are summarized, and the in-situ behavior of openings in bedded salt is described based on extensive engineering experience. A stress measuring system utilizing a finite element computer code is discussed. Geological factors affecting the stability of salt openings are considered, and the Stress Control Technique for designing stable openings in bedded salt formations is explained.

  8. Geomechanics of bedded salt

    International Nuclear Information System (INIS)

    Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temperature is considered. Findings on the permeability of salt are summarized, and the in-situ behavior of openings in bedded salt is described based on extensive engineering experience. A stress measuring system utilizing a finite element computer code is discussed. Geological factors affecting the stability of salt openings are considered, and the Stress Control Technique for designing stable openings in bedded salt formations is explained

  9. 气相色谱-高场非对称波形离子迁移谱(GC-FAIMS)法应用于白酒的风味研究%Study on liquor flavor by gas chromatography-field asymmetric ion mobility spectrometry method

    Institute of Scientific and Technical Information of China (English)

    李娟; 郭亚洁; 赵伟军; 李灵峰; 李鹏; 汪小知

    2014-01-01

    目的:将 FAIMS 与 GC 分离技术联用,建立白酒中风味物质的甄别分析方法。方法首先利用 GC的高分离能力对白酒成分进行预分离,避免了干扰组分带来的离子竞争等问题;然后用 GC-FAIMS 进行检测;最后通过质谱对 GC-FAIMS 谱图中风味物质的出峰信号进行确认,并以各种风味物质含量为依据,通过主成分分析(PCA)法对白酒的不同香型进行划分。结果枝江大曲负模式下各组分峰的保留时间RSD均小于2.15%,峰高RSD均小于3.06%(n=5),系统的稳定性良好。对11种不同香型的白酒进行GC-FAIMS测试,在负模式下响应的组分主要是有机酸类物质。11种不同香型白酒具有较大的象限差异,能够通过PCA分析方法加以区分。结论 GC-FAIMS 联用技术成功实现了多种白酒的香型分析,该联用技术对复杂体系的分析具有一定的应用前景。%ABSTRACT:Objective To establish a method for identification analysis of flavor in liquors. Methods Liq-uor were separated by gas chromatography (GC) technology to avoid the ion of competition issues caused by the interference components, and determined by GC-high-field asymmetric waveform ion mobility spectrome-try (FAIMS). Finally, the peak signal of flavor compounds was confirmed by the mass spectra. Flavor of liquors were analyzed via PSA method. Results The RSDs of retention time were less than 2.15%, and high peak RSDs were below 3.06%(n=5) of each component in negative mode of Zhijiang Daqu, so the stability of the system was good. Response components of 11 kinds of different flavor liquors detected were the organic acids in negative mode. Different quadrant wine showed a great difference, which could be distinguished by PCA analysis methods. Conclusion GC-FAIMS is successfully implemented in liquor flavor analysis. It has an promising application prospect in dealing with complex sample system.

  10. Asymmetric dense matter in holographic QCD

    Directory of Open Access Journals (Sweden)

    Shin Ik Jae

    2012-02-01

    Full Text Available We study asymmetric dense matter in holographic QCD.We construct asymmetric dense matter by considering two quark flavor branes with dierent quark masses in a D4/D6/D6 model. To calculate the symmetry energy in nuclear matter, we consider two quarks with equal masses and observe that the symmetry energy increases with the total charge showing the stiff dependence. This behavior is universal in the sense that the result is independent of parameters in the model. We also study strange (or hyperon matter with one light and one intermediate mass quarks. In addition to the vacuum properties of asymmetric matter, we calculate meson masses in asymmetric dense matter and discuss our results in the light of in-medium kaon masses.

  11. Massless sunset diagrams in finite asymmetric volumes

    CERN Document Server

    Niedermayer, Ferenc

    2016-01-01

    In this paper we present methods to compute massless sunset diagrams in finite asymmetric volumes in the framework of dimensional regularization and lattice regularization. We also consider 1-loop sums in both regularizations.

  12. Asymmetric cryptography based on wavefront sensing.

    Science.gov (United States)

    Peng, Xiang; Wei, Hengzheng; Zhang, Peng

    2006-12-15

    A system of asymmetric cryptography based on wavefront sensing (ACWS) is proposed for the first time to our knowledge. One of the most significant features of the asymmetric cryptography is that a trapdoor one-way function is required and constructed by analogy to wavefront sensing, in which the public key may be derived from optical parameters, such as the wavelength or the focal length, while the private key may be obtained from a kind of regular point array. The ciphertext is generated by the encoded wavefront and represented with an irregular array. In such an ACWS system, the encryption key is not identical to the decryption key, which is another important feature of an asymmetric cryptographic system. The processes of asymmetric encryption and decryption are formulized mathematically and demonstrated with a set of numerical experiments.

  13. Molten salt battery having inorganic paper separator

    Science.gov (United States)

    Walker, Jr., Robert D.

    1977-01-01

    A high temperature secondary battery comprises an anode containing lithium, a cathode containing a chalcogen or chalcogenide, a molten salt electrolyte containing lithium ions, and a separator comprising a porous sheet comprising a homogenous mixture of 2-20 wt.% chrysotile asbestos fibers and the remainder inorganic material non-reactive with the battery components. The non-reactive material is present as fibers, powder, or a fiber-powder mixture.

  14. Worst Asymmetrical Short-Circuit Current

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Holmstrøm, O; Grastrup, L;

    2010-01-01

    In a typical power plant, the production scenario and the short-circuit time were found for the worst asymmetrical short-circuit current. Then, a sensitivity analysis on the missing generator values was realized in order to minimize the uncertainty of the results. Afterward the worst asymmetrical...... short-circuit current was analyzed in order to compare the results with the allowable DC current component based in the IEC. Finally the normal operating condition for the power plant was modeled....

  15. An asymmetric pericyclic cascade approach to oxindoles

    OpenAIRE

    Richmond, Edward

    2014-01-01

    The research in this thesis describes an asymmetric pericyclic cascade approach to the synthesis of a range of enantioenriched oxindoles using enantiopure oxazolidine derived nitrones and disubstituted ketenes. Chapter 1 aims to place this work in the context of the literature, describing other commonly employed or state-of-the-art asymmetric approaches to oxindoles and related compounds. Examples of where these approaches have been used successfully in the total synthesis of related indol...

  16. Asymmetric Federalism in Russia: Cure or Poison?

    OpenAIRE

    Jorge Martinez-Vazquez

    2003-01-01

    In the early years of its existence, the Russian Federation adopted a system of differential treatment of its regions in order to cope with the great degree of diversity present in them. This paper examines the Russian Federation’s asymmetric federalism by evaluating the system’s role, significance and effects on the Federation’s development. The study incorporates a detailed description of the asymmetric federalism over time along with the benefits and costs incurred by its implementation. I...

  17. Asymmetric Membrane Osmotic Capsules for Terbutaline Sulphate

    OpenAIRE

    Gobade, N. G.; Marina Koland; K H Harish

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist...

  18. Novel strategies for asymmetric hydrogenation reactions

    OpenAIRE

    Chen, Dianjun

    2011-01-01

    This thesis describes two novel possibilities for asymmetric hydrogenation: enantioselective hydrogenation using chiral ionic liquid systems and metal-free hydrogenation with boranes. In the first part, asymmetric hydrogenation systems using chiral ionic liquids in combination with racemic rhodium catalyst are presented. Enantioselectivities up to 69% ee were achieved in homogeneous Rh-catalyzed hydrogenation with tropos ligand (BIPHEP, sulfonated BIPHEP) in a proline derived cation chiral io...

  19. Asymmetric septal hypertrophy and hypothyroidism in children.

    OpenAIRE

    Altman, D I; Murray, J.; Milner, S.; Dansky, R; Levin, S. E.

    1985-01-01

    Any echocardiographic study of two children with hypothyroidism demonstrated the presence of asymmetric septal hypertrophy. One child died aged 11 months, and pronounced thickening of the interventricular septum was confirmed at necropsy. There was also hypertrophy of the left ventricular free wall. Histological examination showed only slight muscle fibre disarray, but there was striking vacuolation and hypertrophy of muscle fibres. In the second case, a child aged five years, the asymmetric ...

  20. Crystal structures and hydrogen bonding in the morpholinium salts of four phenoxyacetic acid analogues

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2015-11-01

    Full Text Available The anhydrous salts morpholinium (tetrahydro-2-H-1,4-oxazin-4-ium phenoxyacetate, C4H10NO+·C8H7O3−, (I, morpholinium (4-fluorophenoxyacetate, C4H10NO+·C8H6 FO3−, (II, and isomeric morpholinium (3,5-dichlorophenoxyacetate (3,5-D, (III, and morpholinium (2,4-dichlorophenoxyacetic acid (2,4-D, C4H10NO+·C8H5Cl2O3−, (IV, have been determined and their hydrogen-bonded structures are described. In the crystals of (I, (III and (IV, one of the the aminium H atoms is involved in a three-centre asymmetric cation–anion N—H...O,O′ R12(4 hydrogen-bonding interaction with the two carboxyl O-atom acceptors of the anion. With the structure of (II, the primary N—H...O interaction is linear. In the structures of (I, (II and (III, the second N—H...Ocarboxyl hydrogen bond generates one-dimensional chain structures extending in all cases along [100]. With (IV, the ion pairs are linked though inversion-related N—H...O hydrogen bonds [graph set R42(8], giving a cyclic heterotetrameric structure.

  1. Crushed Salt Constitutive Model

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, G.D.

    1999-02-01

    The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear and hydrostatic consolidation tests. Using the parameter values determined from the fitted database, the constitutive model is validated against constant strain-rate tests. Shaft seal problems are analyzed to demonstrate model-predicted consolidation of the shaft seal crushed-salt component. Based on the fitting statistics, the ability of the model to predict the test data, and the ability of the model to predict load paths and test data outside of the fitted database, the model appears to capture the creep consolidation behavior of crushed salt reasonably well.

  2. Simple models for charge and salt effects in protein crystallisation

    OpenAIRE

    Warren, Patrick B

    2002-01-01

    A simple extension of existing models for protein crystallisation is described, in which salt ions and charge neutrality are explicitly incorporated. This provides a straightforward explanation for the shape of protein crystallisation boundaries, the associated scaling properties seen for lysozyme, and can also explain much of the salt dependence of the second virial coefficient. The analysis has wider implications for the use of pair potentials to understand protein crystallisation.

  3. Boric Ester-Type Molten Salt via Dehydrocoupling Reaction

    Directory of Open Access Journals (Sweden)

    Noriyoshi Matsumi

    2014-11-01

    Full Text Available Novel boric ester-type molten salt was prepared using 1-(2-hydroxyethyl-3-methylimidazolium chloride as a key starting material. After an ion exchange reaction of 1-(2-hydroxyethyl-3-methylimidazolium chloride with lithium (bis-(trifluoromethanesulfonyl imide (LiNTf2, the resulting 1-(2-hydroxyethyl-3-methylimidazolium NTf2 was reacted with 9-borabicyclo[3.3.1]nonane (9-BBN to give the desired boric ester-type molten salt in a moderate yield. The structure of the boric ester-type molten salt was supported by 1H-, 13C-, 11B- and 19F-NMR spectra. In the presence of two different kinds of lithium salts, the matrices showed an ionic conductivity in the range of 1.1 × 10−4–1.6 × 10−5 S cm−1 at 51 °C. This was higher than other organoboron molten salts ever reported.

  4. Molecular Mechanism of Rice in Response to Salt Stress

    Institute of Scientific and Technical Information of China (English)

    E Zhi-guo; ZHANG Li-jing; WANG Lei

    2011-01-01

    Rice is moderately sensitive to salinity,and the response to salt stress is a complex process,including the perception and transduction of salt stress signal,the activation of specific transcriptional factors and the expression of downstream stress-responsive genes.The functions of Na+ transporters which are involved in the maintenance and reconstruction of the ion homeostasis,transcriptional regulators and osmotic regulation genes were reviewed.Salt tolerance of plants are enhanced by Na+ vacuolar compartmentation or efflux or high levels of osmoprotectants accumulation in cytoplasm.%Rice is moderately sensitive to salinity,and the response to salt stress is a complex process,including the perception and transduction of salt stress signal,the activation of specific transcriptional factors and the expression of downstream stress-respon

  5. Gases in molten salts

    CERN Document Server

    Tomkins, RPT

    1991-01-01

    This volume contains tabulated collections and critical evaluations of original data for the solubility of gases in molten salts, gathered from chemical literature through to the end of 1989. Within the volume, material is arranged according to the individual gas. The gases include hydrogen halides, inert gases, oxygen, nitrogen, hydrogen, carbon dioxide, water vapor and halogens. The molten salts consist of single salts, binary mixtures and multicomponent systems. Included also, is a special section on the solubility of gases in molten silicate systems, focussing on slags and fluxes.

  6. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation.

    Science.gov (United States)

    Zhang, Jun; Borg, Matthew K; Sefiane, Khellil; Reese, Jason M

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.

  7. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation.

    Science.gov (United States)

    Zhang, Jun; Borg, Matthew K; Sefiane, Khellil; Reese, Jason M

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface. PMID:26651708

  8. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation

    Science.gov (United States)

    Zhang, Jun; Borg, Matthew K.; Sefiane, Khellil; Reese, Jason M.

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.

  9. Synthesis of Reduced Graphene Oxide-Modified LiMn0.75Fe0.25PO4 Microspheres by Salt-Assisted Spray Drying for High-Performance Lithium-Ion Batteries

    Science.gov (United States)

    Kim, Myeong-Seong; Kim, Hyun-Kyung; Lee, Suk-Woo; Kim, Dong-Hyun; Ruan, Dianbo; Chung, Kyung Yoon; Lee, Sang Hyun; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-05-01

    Microsized, spherical, three-dimensional (3D) graphene-based composites as electrode materials exhibit improved tap density and electrochemical properties. In this study, we report 3D LiMn0.75Fe0.25PO4/reduced graphene oxide microspheres synthesized by one-step salt-assisted spray drying using a mixed solution containing a precursor salt and graphene oxide and a subsequent heat treatment. During this process, it was found that the type of metal salt used has significant effects on the morphology, phase purity, and electrochemical properties of the synthesized samples. Furthermore, the amount of the chelating agent used also affects the phase purity and electrochemical properties of the samples. The composite exhibited a high tap density (1.1 g cm‑3) as well as a gravimetric capacity of 161 mA h g‑1 and volumetric capacity of 281 mA h cm‑3 at 0.05 C-rate. It also exhibited excellent rate capability, delivering a discharge capacity of 90 mA h g‑1 at 60 C-rate. Furthermore, the microspheres exhibited high energy efficiency and good cyclability, showing a capacity retention rate of 93% after 1000 cycles at 10 C-rate.

  10. Synthesis of Reduced Graphene Oxide-Modified LiMn0.75Fe0.25PO4 Microspheres by Salt-Assisted Spray Drying for High-Performance Lithium-Ion Batteries

    Science.gov (United States)

    Kim, Myeong-Seong; Kim, Hyun-Kyung; Lee, Suk-Woo; Kim, Dong-Hyun; Ruan, Dianbo; Chung, Kyung Yoon; Lee, Sang Hyun; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-05-01

    Microsized, spherical, three-dimensional (3D) graphene-based composites as electrode materials exhibit improved tap density and electrochemical properties. In this study, we report 3D LiMn0.75Fe0.25PO4/reduced graphene oxide microspheres synthesized by one-step salt-assisted spray drying using a mixed solution containing a precursor salt and graphene oxide and a subsequent heat treatment. During this process, it was found that the type of metal salt used has significant effects on the morphology, phase purity, and electrochemical properties of the synthesized samples. Furthermore, the amount of the chelating agent used also affects the phase purity and electrochemical properties of the samples. The composite exhibited a high tap density (1.1 g cm-3) as well as a gravimetric capacity of 161 mA h g-1 and volumetric capacity of 281 mA h cm-3 at 0.05 C-rate. It also exhibited excellent rate capability, delivering a discharge capacity of 90 mA h g-1 at 60 C-rate. Furthermore, the microspheres exhibited high energy efficiency and good cyclability, showing a capacity retention rate of 93% after 1000 cycles at 10 C-rate.

  11. Optimization of salt adsorption rate in membrane capacitive deionization.

    Science.gov (United States)

    Zhao, R; Satpradit, O; Rijnaarts, H H M; Biesheuvel, P M; van der Wal, A

    2013-04-01

    Membrane capacitive deionization (MCDI) is a water desalination technique based on applying a cell voltage between two oppositely placed porous electrodes sandwiching a spacer channel that transports the water to be desalinated. In MCDI, ion-exchange membranes are positioned in front of each porous electrode to prevent co-ions from leaving the electrode region during ion adsorption, thereby enhancing the salt adsorption capacity. MCDI can be operated at constant cell voltage (CV), or at a constant electrical current (CC). In this paper, we present both experimental and theoretical results for desalination capacity and rate in MCDI (both in the CV- and the CC-mode) as function of adsorption/desorption time, salt feed concentration, electrical current, and cell voltage. We demonstrate how by varying each parameter individually, it is possible to systematically optimize the parameter settings of a given system to achieve the highest average salt adsorption rate and water recovery. PMID:23395310

  12. The Significance of Interfacial Water Structure in Soluble Salt Flotation Systems.

    Science.gov (United States)

    Hancer, M.; Celik, M. S.; Miller, J. D.

    2001-03-01

    Flotation of soluble salts with dodecyl amine hydrochloride (DAH) and sodium dodecyl sulfate (SDS) collectors has demonstrated that the interfacial water structure and hydration states of soluble salt surfaces together with the precipitation tendency of the corresponding collector salts are of considerable importance in explaining their flotation behavior. In particular, the high concentration of ions in these soluble salt brines and their hydration appear to modify the bulk and interfacial structure of water as revealed by contact angle measurements and this effect is shown to be an important feature in the flotation chemistry of soluble salt minerals including alkali halide and alkali oxyanion salts. Depending on characteristic chemical features (salt type), the salt can serve either as a structure maker, in which intermolecular hydrogen bonding between water molecules is facilitated, or as a structure breaker, in which intermolecular hydrogen bonding between water molecules is disrupted. For structure making salts the brine completely wets the salt surface and no contact angle can be measured. For structure breaking salts the brine does not completely wet the salt surface and a finite contact angle is measured. In this regard it has been found that soluble salt flotation either with the cationic DAH or anionic SDS collector is possible only if the salt is a structure breaker. Copyright 2001 Academic Press. PMID:11237454

  13. Orientation of x-lines in asymmetric magnetic reconnection

    Science.gov (United States)

    Liu, Yi-Hsin; Hesse, Michael; Kuznetsova, Masha

    2015-11-01

    At Earth's magnetopause, reconnection proceeds asymmetrically between magnetosheath plasmas, namely solar wind plasmas compressed by Earth's bow shock, and magnetospheric plasmas. In an asymmetric configuration, it is unclear if there is a simple principle to determine the orientation of the x-line. Using fully kinetic simulations, we study this issue and a spatially localized perturbation is employed to induce a single x-line, that has sufficient freedom to choose its orientation in three-dimensional systems. The effect of ion to electron mass ratio is investigated, and the x-line appears to bisect the magnetic shear angle across the current sheet in the large mass ratio limit. The deviation from the bisection angle in the lower mass ratio limit can be explained by the physics of tearing instability. The local physics control of the x-line orientation studied in this slab geometry could potentially interplay with global geometrical effects to determine the location of collisionless magnetic reconnection at Earth's magnetopause.

  14. Asymmetric switching in a homodimeric ABC transporter: a simulation study.

    Directory of Open Access Journals (Sweden)

    Jussi Aittoniemi

    2010-04-01

    Full Text Available ABC transporters are a large family of membrane proteins involved in a variety of cellular processes, including multidrug and tumor resistance and ion channel regulation. Advances in the structural and functional understanding of ABC transporters have revealed that hydrolysis at the two canonical nucleotide-binding sites (NBSs is co-operative and non-simultaneous. A conserved core architecture of bacterial and eukaryotic ABC exporters has been established, as exemplified by the crystal structure of the homodimeric multidrug exporter Sav1866. Currently, it is unclear how sequential ATP hydrolysis arises in a symmetric homodimeric transporter, since it implies at least transient asymmetry at the NBSs. We show by molecular dynamics simulation that the initially symmetric structure of Sav1866 readily undergoes asymmetric transitions at its NBSs in a pre-hydrolytic nucleotide configuration. MgATP-binding residues and a network of charged residues at the dimer interface are shown to form a sequence of putative molecular switches that allow ATP hydrolysis only at one NBS. We extend our findings to eukaryotic ABC exporters which often consist of two non-identical half-transporters, frequently with degeneracy substitutions at one of their two NBSs. Interestingly, many residues involved in asymmetric conformational switching in Sav1866 are substituted in degenerate eukaryotic NBS. This finding strengthens recent suggestions that the interplay of a consensus and a degenerate NBS in eukaroytic ABC proteins pre-determines the sequence of hydrolysis at the two NBSs.

  15. Gene Response to Salt Stress in Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Shen Xin; Thomas Teichmenn; Wang Yiqin; Bai Genben; Yu Guangjun; Wang Shasheng

    2003-01-01

    Through construction of a subtracted cDNA library and library screening, a number of salt-induced cDNA fragmentshave been cloned from Populus euphratica. Based on the results of DNA sequencing and Northern analysis, the gene response ofPopulus euphratica to salt stress is discussed. It is indicated that in response to salt treatment the transcription level for some genes ofPopulus euphratica increases by about 1.5 times and significant difference between the responses to osmotic stress and to ion stresshas been observed in gene activity.

  16. Salt-free vesicle-phases and their template effect

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Researches on the construction, structure, and formation of vesicles formed from surfactants have attracted great attention from colloid and interface chemists. The vesicles formed from salt-free cationic-anionic surfactant systems are very different from those with excess salts, having many particular properties. In this paper, we introduce the properties of vesicles prepared from salt-free surfactant systems, according to our own results, especially the vesicles formed from surfactants with divalent metal ions as counterions in aqueous solutions and room temperature ionic liquids. Moreover, the primary results on template effect of the metal-ligand vesicles have also been summarized.

  17. Water-Mediated Ion Pairing: Occurrence and Relevance

    DEFF Research Database (Denmark)

    van der Vegt, Nico F.A.; Haldrup, Kristoffer; Roke, Sylvie;

    2016-01-01

    salt solutions and their interfaces, the measured and calculated structure and dynamics reveal the presence of a distinct concentration of contact ion pairs (CIPs), solvent shared ion pairs (SIPs), and solvent-separated ion pairs (2SIPs). We discuss the importance of specific ion-pairing interactions...

  18. Improving the Sensitivity of Matrix-Assisted Ionization (MAI) Mass Spectrometry Using Ammonium Salts.

    Science.gov (United States)

    Chubatyi, Nicholas D; McEwen, Charles N

    2015-10-01

    In matrix-assisted ionization (MAI), analyte incorporated in a small molecule matrix is introduced into an aperture linking atmospheric pressure with the vacuum of a mass spectrometer. Gas-phase analyte ions are spontaneously produced without use of a laser or high voltage. Here we investigate analyte and background ion abundances upon addition of ammonium salts to various MAI matrix/analyte solutions. Regardless of the ammonium salt or matrix used, chemical background ions are suppressed and/or analyte ion abundance improved for basic small molecules, peptides, and proteins. Background ion abundances increase with increasing inlet temperature, but are suppressed with addition of any of a variety of ammonium salts without much effect on the total ion abundances of the analyte ions. However, at lower inlet temperature using the matrices 2-bromo-2-nitropropane-1,3-diol, 1,2-dicyanobenzene, and 3-nitrobenzonitrile (3-NBN), analyte ion abundance increases and any chemical background decreases upon addition of ammonium salt. The improvement in sensitivity using 3-NBN with ammonium salt allows full acquisition mass spectra consuming as little as 1 fmol of ubiquitin. More complete peptide coverage for 100 fmol of a BSA tryptic digest, and increased sensitivity of drugs spiked in urine and saliva were observed after ammonium salt addition to the 3-NBN matrix. PMID:26122522

  19. What Are Bath Salts?

    Science.gov (United States)

    ... Blog Team Concert festivals are all about good music, good friends, and big crowds. But for some ... school, North Carolina: Are bath salts becoming more popular? Marsha Lopez Hi, Lauren. Nope! Actually quite the ...

  20. Asymmetric electrochemical supercapacitor, based on polypyrrole coated carbon nanotube electrodes

    International Nuclear Information System (INIS)

    Highlights: • Polypyrrole (PPy) coated multiwalled carbon nanotubes (MWCNT) were prepared. • New method is based on the use of new electrochemically active dopants for PPy. • The dopans provided dispersion of MWCNT and promoted PPy coating formation. • Symmetric PPy–MWCNT supercapacitors showed high capacitance and low resistance. • Asymmetric PPy–MWCNT/VN–MWCNT devices and modules allowed larger voltage window. - Abstract: Conductive polypyrrole (PPy) polymer – multiwalled carbon nanotubes (MWCNT) composites were synthesized using sulfanilic acid azochromotrop (SPADNS) and sulfonazo III sodium salt (CHR-BS) as anionic dopants for chemical polymerization of PPy. The composites were tested for application in electrodes of electrochemical supercapacitors (ES). Sedimentation tests, electrophoretic deposition experiments and Fourier transform infrared spectroscopy (FTIR) investigations showed that strong adsorption of anionic CHR-BS on MWCNT provided MWCNT dispersion. The analysis of scanning and transmission electron microscopy data demonstrated that the use of CHR-BS allowed the formation of PPy coatings on MWCNT. As a result, the composites, prepared using CHR-BS, showed higher capacitance, compared to the composites, prepared using SPADNS. The electrodes, containing MWCNT, coated with PPy showed a capacitance of 179 F g−1 for active mass loading of 10 mg cm−2, good capacitance retention at scan rates in the range of 2–100 mV s−1 and excellent cyclic stability. Asymmetric ES devices, containing positive PPy–MWCNT electrodes and negative vanadium nitride (VN)–MWCNT electrodes showed significant improvement in energy storage performance, compared to the symmetric ES due to the larger voltage window. The low impedance and high capacitance of the individual cells paved the way to the development of modules with higher voltage, which showed good electrochemical performance

  1. Performance-Enhancing Asymmetric Separator for Lithium-Sulfur Batteries.

    Science.gov (United States)

    Conder, Joanna; Forner-Cuenca, Antoni; Gubler, Elisabeth Müller; Gubler, Lorenz; Novák, Petr; Trabesinger, Sigita

    2016-07-27

    Asymmetric separators with polysulfide barrier properties consisting of porous polypropylene grafted with styrenesulfonate (PP-g-PLiSS) were characterized in lithium-sulfur cells to assess their practical applicability. Galvanostatic cycling at different C-rates with and without an electrolyte additive and cyclic voltammetry were used to probe the electrochemical performance of the cells with the PP-g-PLiSS separators and to compare it with the performance of the cells utilizing state-of-the-art separator, Celgard 2400. Overall, it was found that regardless of the applied cycling rate, the use of the grafted separators greatly enhances the Coulombic efficiency of the cell. An appropriate Li-exchange-site (-SO3(-)) concentration at and near the surface of the separator was found to be essential to effectively suppress the polysulfide shuttle without sacrificing the Li-ion mobility through the separator and to improve the practical specific charge of the cell. PMID:27367443

  2. Asymmetric bilayer graphene nanoribbon MOSFETs for analog and digital electronics

    Science.gov (United States)

    Dinarvand, A.; Ahmadi, V.; Darvish, Gh.

    2016-05-01

    In this paper, a new structure was proposed for bilayer graphene nanoribbon field-effect transistor (BGNFET) mainly to enhance the electrical characteristics in analog and digital applications. The proposed device uses two metallic gates on the top and bottom of a bilayer graphene nanoribbon, which is surrounded by SiO2 and connected to heavily doped source/drain contacts. Electrical properties of the proposed device were explored using fully self-consistent solution of Poisson and Schrödinger equations based on the nonequilibrium Green's function (NEGF) formalism. Significant improvements in the electrical behavior was seen in the simulation results for gates asymmetrically biased. The comparison with graphene nanoribbon FET showed that the proposed structure benefited from higher intrinsic voltage gain and cut-off frequency and improved switching characteristics such as delay and Ion/Ioff ratio.

  3. [Development of new methods in asymmetric reactions and their applications].

    Science.gov (United States)

    Node, Manabu

    2002-01-01

    Several novel methods using chiral reagents and biocatalysts for asymmetric reactions are described. Among those reactions, asymmetric reduction via a novel tandem Michael addition/Meerwein-Ponndorf-Verley reduction of acyclic alpha,beta-unsaturated ketones using a chiral mercapto alcohol, asymmetric synthesis of allene-1,3-dicarboxylate via crystallization induced asymmetric transformation, and improved asymmetric nitroolefination of lactones and lactames at alpha-carbon using new chiral reagents were developed. In the reactions using biocatalysts, asymmetric dealkoxycarbonylation of bicyclic beta-keto diesters having sigma-symmetry with lipase or esterase to give optically active beta-keto esters, the asymmetric reduction of bicyclic 1,3-diketones having sigma-symmetry with Baker's yeast to give optically active keto alcohols, and the asymmetric aldol reaction of glycine with threonine aldolase were also developed. The above mentioned products were effectively utilized as chiral building blocks for the asymmetric synthesis of natural products and drugs.

  4. Performance and cost characteristics of multi-electron transfer, common ion exchange non-aqueous redox flow batteries

    Science.gov (United States)

    Laramie, Sydney M.; Milshtein, Jarrod D.; Breault, Tanya M.; Brushett, Fikile R.; Thompson, Levi T.

    2016-09-01

    Non-aqueous redox flow batteries (NAqRFBs) have recently received considerable attention as promising high energy density, low cost grid-level energy storage technologies. Despite these attractive features, NAqRFBs are still at an early stage of development and innovative design techniques are necessary to improve performance and decrease costs. In this work, we investigate multi-electron transfer, common ion exchange NAqRFBs. Common ion systems decrease the supporting electrolyte requirement, which subsequently improves active material solubility and decreases electrolyte cost. Voltammetric and electrolytic techniques are used to study the electrochemical performance and chemical compatibility of model redox active materials, iron (II) tris(2,2‧-bipyridine) tetrafluoroborate (Fe(bpy)3(BF4)2) and ferrocenylmethyl dimethyl ethyl ammonium tetrafluoroborate (Fc1N112-BF4). These results help disentangle complex cycling behavior observed in flow cell experiments. Further, a simple techno-economic model demonstrates the cost benefits of employing common ion exchange NAqRFBs, afforded by decreasing the salt and solvent contributions to total chemical cost. This study highlights two new concepts, common ion exchange and multi-electron transfer, for NAqRFBs through a demonstration flow cell employing model active species. In addition, the compatibility analysis developed for asymmetric chemistries can apply to other promising species, including organics, metal coordination complexes (MCCs) and mixed MCC/organic systems, enabling the design of low cost NAqRFBs.

  5. Renewable resource management under asymmetric information

    DEFF Research Database (Denmark)

    Jensen, Frank; Andersen, Peder; Nielsen, Max

    2013-01-01

    Asymmetric information between fishermen and the regulator is important within fisheries. The regulator may have less information about stock sizes, prices, costs, effort, productivity and catches than fishermen. With asymmetric information, a strong analytical tool is principal-agent analysis....... In this paper, we study asymmetric information about productivity within a principal-agent framework and a tax on fishing effort is considered. It is shown that a second best optimum can be achieved if the effort tax is designed such that low-productivity agents rent is exhausted, while high-productivity agents...... receive an information rent. The information rent is equivalent to the total incentive cost. The incentive costs arise as we want to reveal the agent's type....

  6. Dc SQUIDs with asymmetric shunt resistors

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, Matthias; Nagel, Joachim; Kemmler, Matthias; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena in LISAplus, Universitaet Tuebingen (Germany); Meckbach, Johannes Maximilian; Ilin, Konstantin; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2013-07-01

    We have investigated asymmetrically shunted Nb/Al-AlO{sub x}/Nb dc SQUIDs. Simulations based on the coupled Langevin equations predict that the optimum energy resolution ε, and thus also the noise performance of such an asymmetric SQUID, can be 3-4 times better than that of its symmetric counterpart. While keeping the total resistance R identical to a comparable symmetric SQUID with R{sup -1} = R{sub 1}{sup -1} + R{sub 2}{sup -1}, we shunted only one of the two Josephson junctions with R = R{sub 1,2}/2. Both types of SQUIDs were characterized with respect to their transport and noise properties at temperature T = 4.2 K, and we compared the experimental results with numerical simulations. Experiments yielded ε ∼ 32 ℎ for an asymmetric SQUID with an inductance L = 22 pH, whereas a comparable symmetric device achieved ε = 110 ℎ.

  7. Asymmetric membrane osmotic capsules for terbutaline sulphate

    Directory of Open Access Journals (Sweden)

    N G Gobade

    2012-01-01

    Full Text Available The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate.

  8. Asymmetric membrane osmotic capsules for terbutaline sulphate.

    Science.gov (United States)

    Gobade, N G; Koland, Marina; Harish, K H

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate. PMID:23204625

  9. Homogeneous asymmetric catalysis in fragrance chemistry.

    Science.gov (United States)

    Ciappa, Alessandra; Bovo, Sara; Bertoldini, Matteo; Scrivanti, Alberto; Matteoli, Ugo

    2008-06-01

    Opposite enantiomers of a chiral fragrance may exhibit different olfactory activities making a synthesis in high enantiomeric purity commercially and scientifically interesting. Accordingly, the asymmetric synthesis of four chiral odorants, Fixolide, Phenoxanol, Citralis, and Citralis Nitrile, has been investigated with the aim to develop practically feasible processes. In the devised synthetic schemes, the key step that leads to the formation of the stereogenic center is the homogeneous asymmetric hydrogenation of a prochiral olefin. By an appropriate choice of the catalyst and the reaction conditions, Phenoxanol, Citralis, and Citralis Nitrile were obtained in high enantiomeric purity, and odor profiles of the single enantiomers were determined.

  10. Asymmetric catalysis with short-chain peptides.

    Science.gov (United States)

    Lewandowski, Bartosz; Wennemers, Helma

    2014-10-01

    Within this review article we describe recent developments in asymmetric catalysis with peptides. Numerous peptides have been established in the past two decades that catalyze a wide variety of transformations with high stereoselectivities and yields, as well as broad substrate scope. We highlight here catalytically active peptides, which have addressed challenges that had thus far remained elusive in asymmetric catalysis: enantioselective synthesis of atropoisomers and quaternary stereogenic centers, regioselective transformations of polyfunctional substrates, chemoselective transformations, catalysis in-flow and reactions in aqueous environments.

  11. Asymmetric counter propagation of domain walls

    Science.gov (United States)

    Andrade-Silva, I.; Clerc, M. G.; Odent, V.

    2016-07-01

    Far from equilibrium systems show different states and domain walls between them. These walls, depending on the type of connected equilibria, exhibit a rich spatiotemporal dynamics. Here, we investigate the asymmetrical counter propagation of domain walls in an in-plane-switching cell filled with a nematic liquid crystal. Experimentally, we characterize the shape and speed of the domain walls. Based on the molecular orientation, we infer that the counter propagative walls have different elastic deformations. These deformations are responsible of the asymmetric counter propagating fronts. Theoretically, based on symmetry arguments, we propose a simple bistable model under the influence of a nonlinear gradient, which qualitatively describes the observed dynamics.

  12. Asymmetric acoustic transmission in multiple frequency bands

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hong-xiang, E-mail: jsdxshx@ujs.edu.cn [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Laboratory of Modern Acoustics, Institute of Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 (China); Yuan, Shou-qi, E-mail: Shouqiy@ujs.edu.cn [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Zhang, Shu-yi [Laboratory of Modern Acoustics, Institute of Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-11-23

    We report both experimentally and numerically that the multi-band device of the asymmetric acoustic transmission is realized by placing two periodic gratings with different periods on both sides of two brass plates immersed in water. The asymmetric acoustic transmission can exist in four frequency bands below 1500 kHz, which arises from the interaction between various diffractions from the two gratings and Lamb modes in the brass plates immersed in water. The results indicate that the device has the advantages of multiple band, broader bandwidth, and simpler structure. Our finding should have great potential applications in ultrasonic devices.

  13. Cell-sized asymmetric lipid vesicles facilitate the investigation of asymmetric membranes

    Science.gov (United States)

    Kamiya, Koki; Kawano, Ryuji; Osaki, Toshihisa; Akiyoshi, Kazunari; Takeuchi, Shoji

    2016-09-01

    Asymmetric lipid giant vesicles have been used to model the biochemical reactions in cell membranes. However, methods for producing asymmetric giant vesicles lead to the inclusion of an organic solvent layer that affects the mechanical and physical characteristics of the membrane. Here we describe the formation of asymmetric giant vesicles that include little organic solvent, and use them to investigate the dynamic responses of lipid molecules in the vesicle membrane. We formed the giant vesicles via the inhomogeneous break-up of a lipid microtube generated by applying a jet flow to an asymmetric planar lipid bilayer. The asymmetric giant vesicles showed a lipid flip-flop behaviour in the membrane, superficially similar to the lipid flip-flop activity observed in apoptotic cells. In vitro synthesis of membrane proteins into the asymmetric giant vesicles revealed that the lipid asymmetry in bilayer membranes improves the reconstitution ratio of membrane proteins. Our asymmetric giant vesicles will be useful in elucidating lipid–lipid and lipid–membrane protein interactions involved in the regulation of cellular functions.

  14. A single pump cycling-column-switching technique coupled with homemade high exchange capacity columns for the determination of iodate in iodized edible salt by ion chromatography with UV detection.

    Science.gov (United States)

    Huang, Zhongping; Subhani, Qamar; Zhu, Zuoyi; Guo, Weiqiang; Zhu, Yan

    2013-08-15

    A single pump cycling-column-switching technique has been developed for the iodate analysis in edible salt. Homemade high exchange capacity columns were adopted for the separation of iodate and chloride. Iodate could be retained and concentrated in a homemade concentrator column after eluents passing through the suppressor. With UV detection, iodate exhibited satisfactory linearity in the range of 0.1-10.0 mg/L with a correlation coefficient of 0.9996. The detection limit (LOD) was 45.53 μg/L, based on the signal-to-noise ratio of 3 (S/N=3) and a 100 μL injection volume. Relative standard deviations (RSDs) for retention time, peak area and peak height were all less than 2.1%. Recoveries of added iodate were in the range of 98.4-101.6% for the spiked samples. The quantitative determination of iodate in edible salt was accomplished by this column-switching technique, without any pretreatment and interference. The results on six samples were statistically compared with results determined by conventional titrimetric method. PMID:23561090

  15. Study of the energy inventory during asymmetric magnetic reconnection in a laboratory plasma

    Science.gov (United States)

    Yoo, Jongsoo; Yamada, Masaaki; Na, Ben; Jara-Almonte, Jonathan; Ji, Hantao; Fox, Will; Chien, Abe

    2015-11-01

    The energy inventory of a magnetic reconnection layer is studied in a laboratory plasma with a significant density asymmetry across the current sheet. The upstream density ratio of about 7 is generated by the in-plane inductive electric field during the plasma formation in MRX. Compared to the symmetric case where the ion energy gain is about twice more than that of electrons, the ion energy gain becomes smaller and the electron energy gain is larger. The reduction in the ion energy gain is mainly caused by the asymmetric profile of the in-plane electrostatic potential, which is generated to balance the Lorentz force in the electron momentum equation. Since the out-of-plane electron fluid velocity on the high-density side is small due to the high density, the potential drop on the high-density side becomes also small. The potential drop on the low-density side is also smaller than expected from the general scaling (~B2 / n), since it is suppressed by a large density gradient across the low-density side separatrices. As a result, the ion energy gain from the in-plane electrostatic field is smaller than the symmetric case, thereby decreasing the total ion energy gain. Discussion on the electron energization process during asymmetric reconnection is also presented. This research is supported by DoE Contract Number DE-AC02-09CH11466.

  16. Salt treatment Fukushima

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Stefan [NUKEM Technologies GmbH, Alzenau (Germany)

    2013-07-01

    The Task of NUKEM Technologies GmbH is to develop a technical solution for the treatment of salt containing effluents at Fukushima Daiichi. The target of the treatment is a solidified product suitable for the safe storage on site. Therefore, NUKEM investigated several technologies (direct cementation, drying and storage, drying and subsequent cementation) in order to find a fit for purpose solution. The following tasks have been considered: (a) Mechanical strength and homogeneity of the product; (b) Cost efficient solution (cost for the drying system vs. reduced amount of storage containers); (c) Proven technology; (d) On site storage. NUKEM made some practical test in parallel with different recipes. The aim was to embed as much as possible salt quantity into the cement matrix, but still meet the requested mechanical strength and required homogeneity. As a result NUKEM recommended to apply the following technologies (a) a drying system, to produce a dry salt product (b) a cementation facility, to generate a homogeneous salt/cement matrix (c) a filling station with attached CMS (Container measuring station) to fill the resulting cement/salt matrix into containers suitable for the storage at Fukushima Daiichi. (orig.)

  17. Fundamental Properties of Salts

    Energy Technology Data Exchange (ETDEWEB)

    Toni Y Gutknecht; Guy L Fredrickson

    2012-11-01

    Thermal properties of molten salt systems are of interest to electrorefining operations, pertaining to both the Fuel Cycle Research & Development Program (FCR&D) and Spent Fuel Treatment Mission, currently being pursued by the Department of Energy (DOE). The phase stability of molten salts in an electrorefiner may be adversely impacted by the build-up of fission products in the electrolyte. Potential situations that need to be avoided, during electrorefining operations, include (i) fissile elements build up in the salt that might approach the criticality limits specified for the vessel, (ii) electrolyte freezing at the operating temperature of the electrorefiner due to changes in the liquidus temperature, and (iii) phase separation (non-homogenous solution). The stability (and homogeneity) of the phases can be monitored by studying the thermal characteristics of the molten salts as a function of impurity concentration. Simulated salt compositions consisting of the selected rare earth and alkaline earth chlorides, with a eutectic mixture of LiCl-KCl as the carrier electrolyte, were studied to determine the melting points (thermal characteristics) using a Differential Scanning Calorimeter (DSC). The experimental data were used to model the liquidus temperature. On the basis of the this data, it became possible to predict a spent fuel treatment processing scenario under which electrorefining could no longer be performed as a result of increasing liquidus temperatures of the electrolyte.

  18. Burn-off dominated uranium and asymmetric copper-gold operation in RHIC

    Science.gov (United States)

    Luo, Y.; Fischer, W.; Blaskiewicz, M.; Brennan, J. M.; Kling, N.; Mernick, K.; Roser, T.

    2014-08-01

    In 2012 the Relativistic Heavy Ion Collider collided uranium-uranium ions with a particle energy of 96.4 GeV/nucleon and copper-gold (Cu-Au) ions at 100 GeV/nucleon for the first time. 3-dimensional stochastic cooling became operational for the first time and greatly enhanced the luminosity. Together with a new lattice configuration, we achieved a burn-off dominated uranium beam lifetime at physics stores. In the asymmetric Cu-Au collision, we observed an increased Cu beam loss stemming from different intrabeam-scattering and cooling rates between the Au and Cu ion bunches. By intentionally slowing down the cooling rate for the Au beam at the beginning of store, we reduced the Cu beam loss and maximized the integrated luminosity.

  19. Clean Salt integrated flowsheet

    International Nuclear Information System (INIS)

    The Clean Salt Process (CSP) is a novel waste management scheme that removes sodium nitrate and aluminum nitrate nonahydrate as decontaminated (low specific activity) salts from Hanford's high-level waste (HLW). The full scale process will separate the bulk of the waste that exists as sodium salts from the small portion of the waste that is by definition radioactive and dangerous. This report presents initial conceptual CSP flowsheets and demonstrates the benefit of integrating the process into the Tank Waste Remediation Systems (TWRS) Reference Flowsheet. Total HLW and low-level (LLW) volumes are reported for two different CSP integration options and are compared to the TWRS Reference Flowsheet values. The results for a single glass option eliminating LLW disposal are also reported

  20. Mineral resource of the month: salt

    Science.gov (United States)

    Kostick, Dennis S.

    2010-01-01

    The article presents information on various types of salt. Rock salt is either found from underground halite deposits or near the surface. Other types of salt include solar salt, salt brine, and vacuum pan salt. The different uses of salt are also given including its use as a flavor enhancer, as a road deicing agent, and to manufacture sodium hydroxide.

  1. Gas releases from salt

    Energy Technology Data Exchange (ETDEWEB)

    Ehgartner, B.; Neal, J.; Hinkebein, T.

    1998-06-01

    The occurrence of gas in salt mines and caverns has presented some serious problems to facility operators. Salt mines have long experienced sudden, usually unexpected expulsions of gas and salt from a production face, commonly known as outbursts. Outbursts can release over one million cubic feet of methane and fractured salt, and are responsible for the lives of numerous miners and explosions. Equipment, production time, and even entire mines have been lost due to outbursts. An outburst creates a cornucopian shaped hole that can reach heights of several hundred feet. The potential occurrence of outbursts must be factored into mine design and mining methods. In caverns, the occurrence of outbursts and steady infiltration of gas into stored product can effect the quality of the product, particularly over the long-term, and in some cases renders the product unusable as is or difficult to transport. Gas has also been known to collect in the roof traps of caverns resulting in safety and operational concerns. The intent of this paper is to summarize the existing knowledge on gas releases from salt. The compiled information can provide a better understanding of the phenomena and gain insight into the causative mechanisms that, once established, can help mitigate the variety of problems associated with gas releases from salt. Outbursts, as documented in mines, are discussed first. This is followed by a discussion of the relatively slow gas infiltration into stored crude oil, as observed and modeled in the caverns of the US Strategic Petroleum Reserve. A model that predicts outburst pressure kicks in caverns is also discussed.

  2. Some Physiological Responses of Chinese Iris to Salt Stress

    Institute of Scientific and Technical Information of China (English)

    BAI Wen-Bo; LI Pin-Fang; LI Bao-Guo; H. FUJIYAMA; FAN Fen-Cheng

    2008-01-01

    Chinese iris (Iris lactea Pall. Var. Chinensis (Fisch) Koidz.), a robust iridaceous plant, is widesprcad in arid and semiarid regions with high salinity. However, the mechanism of its salt tolerance is not well understood. In this study,plant growth, water status, content and distribution of inorganic ions, cell membrane permeability, and proline content of I. Lactea under salt stress were investigated using nutrient solutions with six NaCl concentrations ranging from 0 to 350 mmol L-1. The results indicated that the biomass, height, fresh weight, K+ content, and K+/Na+ and Ca2+/Na+ratios decreased with increasing NaCl stress, whereas plant water deficit and contents of Na+ and Cl- increased with increasing NaCl stress. In all salt treatments, water deficit of shoots was found to be higher than that of roots and had a positive correlation with salt concentration. When the NaCl concentration was less than 280 mmol L-1, the ion absorption selectivity ratio and the transportation selectivity ratio sharply increased with increasing NaCl stress. Under medium salt stress, I. Lactea exhibited a strong K+ selective absorption and the transportation of K+ from roots to shoots increased, whereas Na+ was not transported and was mostly retained in roots. The plants were able to maintain osmotic adjustment through the accumulation of Na+, Cl-, and proline. On the basis of its biomass production under salt stress,I. Lactea could be considered as a facultative halophyte.

  3. Asymmetric conditional volatility in international stock markets

    Science.gov (United States)

    Ferreira, Nuno B.; Menezes, Rui; Mendes, Diana A.

    2007-08-01

    Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the SP 500, FTSE 100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of changes in macroeconomic variables, we find no significant evidence of asymmetric behaviour of the stock market returns. There are some signs that the Portuguese Stock Market tends to show somewhat less market efficiency than other markets since the effect of the shocks appear to take a longer time to dissipate.

  4. Weak chaos in the asymmetric heavy top

    CERN Document Server

    Barrientos, M; Ranada, A F

    1995-01-01

    We consider the dynamics of the slightly asymmetric heavy top, a non-integrable system obtained from the Lagrange top by breaking the symmetry of its inertia tensor. It shows signs of weak chaos, which we study numerically. We argue that it is a good example for introducing students to non-integrability and chaos. (author)

  5. Asymmetric cell division: a persistent issue?

    OpenAIRE

    Aakre, Christopher D.; Laub, Michael T.

    2012-01-01

    Heterogeneity within a clonal population of cells can increase survival in the face of environmental stress. In a recent issue of Science, Aldridge et al. (2012) demonstrate that cell division in mycobacteria is asymmetric, producing daughter cells that differ in size, growth rate, and susceptibility to antibiotics.

  6. Asymmetric Total Synthesis of (-)-Cladospolide B

    Institute of Scientific and Technical Information of China (English)

    WANG,Wen-Kuan; ZHANG,Ji-Yong; HE,Jin-Mei; TANG,Shi-Bing; WANG,Xiao-Lei; SHE,Xue-Gong; PAN,Xin-Fu

    2008-01-01

    An enantioselective total synthesis of (-)-cladospolide B was described.The key steps in this synthesis include (a) a Sharpless asymmetric dihydroxylation to elaborate syn diol at C-4 and C-5 positions;(b) a Mitsunobu esterification to reverse the configuration at C-11 from (S) to (R);and (c) a ring-closing metathesis to access the 12-membered macrocyclic ring.

  7. Evidence of asymmetric top in 130Ba

    International Nuclear Information System (INIS)

    Introduced is a new relation connecting moment of inertia, Lipas parameter and asymmetric rotor model energies and put forward much closer trend in odd even staggering of quasi γ-band. A different view point regarding generation of quasi γ-band in 130Ba have been presented

  8. The Asymmetric Effects of Investor Sentiment

    DEFF Research Database (Denmark)

    Lutz, Chandler

    2016-01-01

    are asymmetric: During peak-to-trough periods of investor sentiment (sentiment contractions), high sentiment predicts low future returns for the cross section of speculative stocks and for the market overall, whereas the relationship between sentiment and future returns is positive but relatively weak during...... trough-to-peak episodes (sentiment expansions). Overall, these results match theories and anecdotal accounts of investor sentiment....

  9. Detection loophole in asymmetric Bell experiments

    OpenAIRE

    Brunner, Nicolas; Gisin, Nicolas; Scarani, Valerio; Simon, Christoph

    2007-01-01

    The problem of closing the detection loophole with asymmetric systems, such as entangled atom-photon pairs, is addressed. We show that, for the Bell inequality I_3322, a minimal detection efficiency of 43% can be tolerated for one of the particles, if the other one is always detected. We also study the influence of noise and discuss the prospects of experimental implementation.

  10. Beam-beam issues in asymmetric colliders

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e{sup +}- e{sup -} colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II).

  11. Attentional Control and Asymmetric Associative Priming

    Science.gov (United States)

    Hutchison, Keith A.; Heap, Shelly J.; Neely, James H.; Thomas, Matthew A.

    2014-01-01

    Participants completed a battery of 3 attentional control (AC) tasks (OSPAN, antisaccade, and Stroop, as in Hutchison, 2007) and performed a lexical decision task with symmetrically associated (e.g., "sister-brother") and asymmetrically related primes and targets presented in both the forward (e.g., "atom-bomb") and backward…

  12. Catalytic asymmetric synthesis of mycocerosic acid

    NARCIS (Netherlands)

    ter Horst, B.; Feringa, B.L.; J. Minnaard, A.

    2007-01-01

    The first catalytic asymmetric total synthesis of mycocerosic acid was achieved via the application of iterative enantioselective 1,4-addition reactions and allows for the efficient construction of 1,3-polymethyl arrays with full stereocontrol; further exemplified by the synthesis of tetramethyl-dec

  13. Asymmetric relationships between proteins shape genome evolution.

    NARCIS (Netherlands)

    Notebaart, R.A.; Kensche, P.R.; Huynen, M.A.; Dutilh, B.E.

    2009-01-01

    BACKGROUND: The relationships between proteins are often asymmetric: one protein (A) depends for its function on another protein (B), but the second protein does not depend on the first. In metabolic networks there are multiple pathways that converge into one central pathway. The enzymes in the conv

  14. Salt stabilizer for preventing chlorine depletion and increasing shelf-life of potable water - A concept

    Science.gov (United States)

    Copeland, E. J.; Edgerley, R. H.

    1971-01-01

    Proposed concept, based on law of mass action uses addition of salt to increase chlorine ions produced in sodium hydrochlorite solutions, thereby increasing solution shelf-life. This technique is not costly. Usefulness will be determined by acceptability of salt in product undergoing long shelf-life.

  15. HIGH YIELD AND RAPID SYNTHESES METHODS FOR PRODUCING METALLO-ORGANIC SALTS

    DEFF Research Database (Denmark)

    2005-01-01

    A new method for preparing salts of metal cations and organic acids, especially divalent salts of alkaline earth metal ions from group II of the periodic system and carboxylic acids. The method comprising the use of a high temperature (about 90° or more) and, optionally. high pressure, in order to...

  16. Mechanism for salt scaling

    Science.gov (United States)

    Valenza, John J., II

    Salt scaling is superficial damage caused by freezing a saline solution on the surface of a cementitious body. The damage consists of the removal of small chips or flakes of binder. The discovery of this phenomenon in the early 1950's prompted hundreds of experimental studies, which clearly elucidated the characteristics of this damage. In particular it was shown that a pessimum salt concentration exists, where a moderate salt concentration (˜3%) results in the most damage. Despite the numerous studies, the mechanism responsible for salt scaling has not been identified. In this work it is shown that salt scaling is a result of the large thermal expansion mismatch between ice and the cementitious body, and that the mechanism responsible for damage is analogous to glue-spalling. When ice forms on a cementitious body a bi-material composite is formed. The thermal expansion coefficient of the ice is ˜5 times that of the underlying body, so when the temperature of the composite is lowered below the melting point, the ice goes into tension. Once this stress exceeds the strength of the ice, cracks initiate in the ice and propagate into the surface of the cementitious body, removing a flake of material. The glue-spall mechanism accounts for all of the characteristics of salt scaling. In particular, a theoretical analysis is presented which shows that the pessimum concentration is a consequence of the effect of brine pockets on the mechanical properties of ice, and that the damage morphology is accounted for by fracture mechanics. Finally, empirical evidence is presented that proves that the glue-small mechanism is the primary cause of salt scaling. The primary experimental tool used in this study is a novel warping experiment, where a pool of liquid is formed on top of a thin (˜3 mm) plate of cement paste. Stresses in the plate, including thermal expansion mismatch, result in warping of the plate, which is easily detected. This technique revealed the existence of

  17. Standards vs. labels with imperfect competition and asymmetric information

    DEFF Research Database (Denmark)

    Baltzer, Kenneth Thomas

    I demonstrate that providing information about product quality is not necessarily the best way to address asymmetric information problems when markets are imperfectly competitive. In a vertical dierentiation model I show that a Minimum Quality Standard, which retains asymmetric information...

  18. Standards vs. labels with imperfect competition and asymmetric information

    DEFF Research Database (Denmark)

    Baltzer, Kenneth Thomas

    2012-01-01

    I demonstrate that providing information about product quality is not necessarily the best way to address asymmetric information problems when markets are imperfectly competitive. In a vertical differentiation model I show that a Minimum Quality Standard, which retains asymmetric information...

  19. Asymmetric Bulkheads for Cylindrical Pressure Vessels

    Science.gov (United States)

    Ford, Donald B.

    2007-01-01

    Asymmetric bulkheads are proposed for the ends of vertically oriented cylindrical pressure vessels. These bulkheads, which would feature both convex and concave contours, would offer advantages over purely convex, purely concave, and flat bulkheads (see figure). Intended originally to be applied to large tanks that hold propellant liquids for launching spacecraft, the asymmetric-bulkhead concept may also be attractive for terrestrial pressure vessels for which there are requirements to maximize volumetric and mass efficiencies. A description of the relative advantages and disadvantages of prior symmetric bulkhead configurations is prerequisite to understanding the advantages of the proposed asymmetric configuration: In order to obtain adequate strength, flat bulkheads must be made thicker, relative to concave and convex bulkheads; the difference in thickness is such that, other things being equal, pressure vessels with flat bulkheads must be made heavier than ones with concave or convex bulkheads. Convex bulkhead designs increase overall tank lengths, thereby necessitating additional supporting structure for keeping tanks vertical. Concave bulkhead configurations increase tank lengths and detract from volumetric efficiency, even though they do not necessitate additional supporting structure. The shape of a bulkhead affects the proportion of residual fluid in a tank that is, the portion of fluid that unavoidably remains in the tank during outflow and hence cannot be used. In this regard, a flat bulkhead is disadvantageous in two respects: (1) It lacks a single low point for optimum placement of an outlet and (2) a vortex that forms at the outlet during outflow prevents a relatively large amount of fluid from leaving the tank. A concave bulkhead also lacks a single low point for optimum placement of an outlet. Like purely concave and purely convex bulkhead configurations, the proposed asymmetric bulkhead configurations would be more mass-efficient than is the flat

  20. Salt Contribution to the Flexibility of Single-stranded Nucleic Acid of Finite Length

    CERN Document Server

    Wang, Feng-Hua; Tan, Zhi-Jie

    2012-01-01

    Nucleic acids are negatively charged macromolecules and their structure properties are strongly coupled to metal ions in solutions. In this paper, the salt effects on the flexibility of single stranded (ss) nucleic acid chain ranging from 12 to 120 nucleotides are investigated systematically by the coarse grained Monte Carlo simulations where the salt ions are considered explicitly and the ss chain is modeled with the virtual bond structural model. Our calculations show that, the increase of ion concentration causes the structural collapse of ss chain and multivalent ions are much more efficient in causing such collapse, and trivalent and small divalent ions can both induce more compact state than a random relaxation state. We found that monovalent, divalent and trivalent ions can all overcharge ss chain, and the dominating source for such overcharging changes from ion exclusion volume effect to ion Coulomb correlations. In addition, the predicted Na and Mg dependent persistence length lp of ss nucleic acid a...

  1. Charge Asymmetric Cosmic Rays as a probe of Flavor Violating Asymmetric Dark Matter

    DEFF Research Database (Denmark)

    Masina, Isabella; Sannino, Francesco

    2011-01-01

    The recently introduced cosmic sum rules combine the data from PAMELA and Fermi-LAT cosmic ray experiments in a way that permits to neatly investigate whether the experimentally observed lepton excesses violate charge symmetry. One can in a simple way determine universal properties of the unknown...... component of the cosmic rays. Here we attribute a potential charge asymmetry to the dark sector. In particular we provide models of asymmetric dark matter able to produce charge asymmetric cosmic rays. We consider spin zero, spin one and spin one-half decaying dark matter candidates. We show that lepton...... flavor violation and asymmetric dark matter are both required to have a charge asymmetry in the cosmic ray lepton excesses. Therefore, an experimental evidence of charge asymmetry in the cosmic ray lepton excesses implies that dark matter is asymmetric....

  2. On the influence that the ground electrode diameter has in the propulsion efficiency of an asymmetric capacitor in nitrogen gas

    CERN Document Server

    Martins, Alexandre A

    2011-01-01

    In this work the propulsion force developed in an asymmetric capacitor will be calculated for three different diameters of the ground electrode. The used ion source is a small diameter wire, which generates a positive corona discharge in nitrogen gas directed to the ground electrode. By applying the fluid dynamic and electrostatic theories all hydrodynamic and electrostatic forces that act on the considered geometries will be computed in an attempt to provide a physical insight on the force mechanism that acts on the asymmetrical capacitors, and also to understand how to increase the efficiency of propulsion.

  3. Surviving in a semi-marine habitat: Dietary salt exposure and salt secretion of a New Zealand intertidal skink.

    Science.gov (United States)

    Janssen, Jordi; Towns, David R; Duxbury, Mark; Heitkönig, Ignas M A

    2015-11-01

    Species that inhabit marine and intertidal ecosystems face osmoregulatory challenges, risking dehydration and increased ion concentrations in the body. Lizards need to either tolerate or regulate these increased ion concentrations. In this study, we aim to understand how Suter's skink (Oligosoma suteri), an intertidal skink restricted to shoreline habitats, is able to cope with the physiological stress of living in an extreme salt environment. We determined the diet, prey species' salt content, and nasal and cloacal salt excretion on Rangitoto and Motutapu Islands in northern New Zealand, where the skinks have contrasting access to terrestrial invertebrates. Analysis of stable isotopes suggests inter- and intra-population variability in Suter's skink diets. Intertidal invertebrates under washed up seaweed appear to compose a major part of the diet of the Rangitoto population, while the Motutapu population showed evidence for a mixed diet of terrestrial and intertidal invertebrates. Sodium content of prey species decreased with an increasing distance from the seawater. Field secretion of cations through nasal glands consisted primarily of Na(+), which is consistent with other marine and intertidal species. Sodium was also the primary cation in urine. In contrast, fecal cations consisted primarily of K(+). This first study into the salt secretion of an intertidal skink species provides evidence of Suter's skink's plasticity in secreting excess ions through nasal salt glands. This likely enables it to deal with the challenges of living in a semi-marine habitat. PMID:26188169

  4. Ion-pair triple helicates and mesocates self-assembled from ditopic 2,2 -bipyridine-bis(urea) ligands and Ni(II) and Fe(II) sulfate salts

    Energy Technology Data Exchange (ETDEWEB)

    Custelcean, Radu [ORNL; Bonnesen, Peter V [ORNL; Roach, Benjamin D [ORNL; Duncan, Nathan C [ORNL

    2012-01-01

    NiSO{sub 4} and FeSO{sub 4} self-assemble with heteroditopic ligands (L) comprising 2,2{prime}-bipyridine and o-phenylene-(bis)urea cation- and anion-binding sites, respectively, into [ML{sub 3}SO{sub 4}] (M = Ni{sup 2+}, Fe{sup 2+}) triple-stranded ion-pair helicates and mesocates.

  5. Improvement of penning ion sources

    CERN Document Server

    Bizyukov, A A; Kashaba, A Y; Sereda, K N

    2000-01-01

    It is shown that the loss of a longitudinal symmetry of magnetic field distribution in respect to the centre of the Penning discharge system causes change of electrostatic potential distribution in the discharge gap leads to appearance of asymmetry of current magnitude to the cathodes of the Penning cell,change of magnitude of current density and energy distribution of the ion beam extracted in a longitudinal direction.The use of an inhomogeneous magnetic field which is longitudinally asymmetrical concerning electrodes of the system allows to increase current efficiency of Penning ion sources from 0,2 to 0,55.

  6. Asymmetric dual-gate tunneling FET with improved performance

    Science.gov (United States)

    Wang, Ying; Wang, Yan-fu; Xue, Wei; Cao, Fei

    2016-03-01

    In this work, we propose and simulate an asymmetric dual-gate tunneling FET (ADG-TFET) combining a tunneling field effect transistor (TFET) with a junctionless field effect transistor (JLFET). The current is controlled by an in the bottom channel potential barrier as well as the reverse-biased P+ pocket-Intrinsic region (p-i) tunnel junction bandgap, which combines the merits of both bandgap-controlled TFET and barrier-controlled JLFET. The simulation results of ADG-TFET with high-κ dielectric material (HfO2) of 40-nm gate length show excellent characteristics with high ION/IOFF ratio of 3.3 × 1010 and ION of 302 μA/μm, a steep subthreshold slope (SS) for point SS of 35 mV/decade and average SS of 54 mV/decade at room temperature, which indicates that ADG-TFET is a promising candidate for future low power circuit applications.

  7. Controlling the profile of ion-cyclotron-resonant ions in JET with the wave-induced pinch effect

    NARCIS (Netherlands)

    Mantsinen, M. J.; Ingesson, L. C.; Johnson, T.; Kiptily, V. G.; Mayoral, M. L.; Sharapov, S. E.; Alper, B.; Bertalot, L.; Conroy, S.; Eriksson, L. G.; Hellsten, T.; Noterdaeme, J. M.; Popovichev, S.; Righi, E.; Tuccillo, A. A.

    2002-01-01

    Experiments on the JET tokamak show that the wave-induced pinch in the presence of toroidally asymmetric waves can provide a tool for controlling the profile of ion-cyclotron-resonant He-3 ions. Direct evidence for the wave-induced pinch has been obtained from the measured gamma-ray emission profile

  8. Influence of Salts on the Partitioning of 5-Hydroxymethylfurfural in Water/MIBK.

    Science.gov (United States)

    Mohammad, Sultan; Held, Christoph; Altuntepe, Emrah; Köse, Tülay; Sadowski, Gabriele

    2016-04-28

    This study investigates the influence of electrolytes on the performance of extracting 5-hydroxymethylfurfural (HMF) from aqueous media using methyl isobutyl ketone (MIBK). For that purpose, liquid-liquid phase equilibria (LLE) of quaternary systems containing HMF, water, MIBK and salts were measured at atmospheric pressure and 298.15 K. The salts under investigation were composed of one of the anions NO(3-), SO4(2-), Cl(-), or CH3COO(-) and of one of the alkali cations Li(+), Na(+), or K(+). On the basis of these LLE data, the partition coefficient of HMF between the aqueous and the MIBK phase KHMF was determined. It could be shown that KHMF significantly depends on the kind and concentration of the added salt. Weak electrolytes (e.g., sulfates, acetates) caused salting-out, whereas nitrates caused salting-in of HMF to the aqueous phase. Unexpectedly, LiCl caused salting-out at low LiCl concentrations and salting-in at LiCl concentrations higher than 3 mol/kgH2O. The model electrolyte perturbed-chain SAFT (ePC-SAFT) was used to predict the salt influence on the LLE in the quaternary systems water/MIBK/HMF/salt in good agreement with the experimental data. On the basis of ePC-SAFT, it could be concluded that the different salting-out/salting-in behavior of the various salts is mainly caused by their different tendency to form ion pairs in aqueous solutions. PMID:27027570

  9. Learning SaltStack

    CERN Document Server

    Myers, Colton

    2015-01-01

    If you are a system administrator who manages multiple servers, then you know how difficult it is to keep your infrastructure in line. If you've been searching for an easier way, this book is for you. No prior experience with SaltStack is required.

  10. A study of salt effects on the complexation between beta-cyclodextrins and bile salts based on the Hofmeister series

    DEFF Research Database (Denmark)

    Holm, Rene; Schonbeck, Christian; Somprasirt, Pitchayanun;

    2014-01-01

    bound drug molecules. The influence of Hofmeister ions on the binding constants of complexes between CDs (β-CD and hydroxypropylated β-CD) and bile salts (glycocholate and glycochenodeoxycholate) were examined by isothermal titration calorimetry. The chaotropic anions tended to weaken these inclusion...

  11. Ion exchange technology assessment report

    International Nuclear Information System (INIS)

    In the execution of its charter, the SRS Ion Exchange Technology Assessment Team has determined that ion exchange (IX) technology has evolved to the point where it should now be considered as a viable alternative to the SRS reference ITP/LW/PH process. The ion exchange media available today offer the ability to design ion exchange processing systems tailored to the unique physical and chemical properties of SRS soluble HLW's. The technical assessment of IX technology and its applicability to the processing of SRS soluble HLW has demonstrated that IX is unquestionably a viable technology. A task team was chartered to evaluate the technology of ion exchange and its potential for replacing the present In-Tank Precipitation and proposed Late Wash processes to remove Cs, Sr, and Pu from soluble salt solutions at the Savannah River Site. This report documents the ion exchange technology assessment and conclusions of the task team

  12. Salt enrichment of municipal sewage: New prevention approaches in Israel

    Science.gov (United States)

    Weber, Baruch; Avnimelech, Yoram; Juanico, Marcelo

    1996-07-01

    Wastewater irrigation is an environmentally sound wastewater disposal practice, but sewage is more saline than the supplied fresh water and the salts are recycled together with the water. Salts have negative environmental effects on crops, soils, and groundwater. There are no inexpensive ways to remove the salts once they enter sewage, and the prevention of sewage salt enrichment is the most immediately available solution. The body of initiatives presently structured by the Ministry of the Environment of Israel are herein described, with the aim to contribute to the search for a long-term solution of salinity problems in arid countries. The new initiatives are based on: (1) search for new technologies to reduce salt consumption and discharge into sewage; (2) different technologies to cope with different situations; (3) raising the awareness of the public and industry on the environmental implications of salinity pollution; and (4) an elastic legal approach expressed through new state-of-the-art regulations. The main contributor to the salinity of sewage in Israel is the watersoftening process followed by the meat koshering process. Some of the adopted technical solutions are: the discharge of the brine into the sea, the substitution of sodium by potassium salts in the ion-exchangers, the construction of centralized systems for the supply of soft water in industrial areas, the precipitation of Ca and Mg in the effluents from ion-exchangers and recycling of the NaCI solution, a reduction of the discharge of salts by the meat koshering process, and new membrane technology for salt recovery.

  13. Surface design and engineering of hierarchical hybrid nanostructures for asymmetric supercapacitors with improved electrochemical performance.

    Science.gov (United States)

    Achilleos, Demetra S; Hatton, T Alan

    2015-06-01

    With the current rising world demand for energy sufficiency, there is an increased necessity for the development of efficient energy storage devices. To address these needs, the scientific community has focused on the improvement of the electrochemical properties of the most well known energy storage devices; the Li-ion batteries and electrochemical capacitors, also called supercapacitors. Despite the fact that supercapacitors exhibit high power densities, good reversibility and long cycle life, they still exhibit lower energy densities than batteries, which limit their practical application. Various strategies have been employed to circumvent this problem, specifically targetting an increase in the specific capacitance and the broadening of the potential window of operation of these systems. In recent years, sophisticated surface design and engineering of hierarchical hybrid nanostructures has facilitated significant improvements in the specific and volumetric storage capabilities of supercapacitors. These nanostructured electrodes exhibit higher surface areas for ion adsorption and reduced ion diffusion lengths for the electrolyte ions. Significant advances have also been achieved in broadening the electrochemical window of operation of these systems, as realized via the development of asymmetric two-electrode cells consisting of nanocomposite positive and negative electrodes with complementary electrochemical windows, which operate in environmentally benign aqueous media. We provide an overview of the diverse approaches, in terms of chemistry and nanoscale architecture, employed recently for the development of asymmetric supercapacitors of improved electrochemical performance. PMID:25711524

  14. Preconceptual design of a salt splitting process using ceramic membranes

    International Nuclear Information System (INIS)

    Inorganic ceramic membranes for salt splitting of radioactively contaminated sodium salt solutions are being developed for treating U. S. Department of Energy tank wastes. The process consists of electrochemical separation of sodium ions from the salt solution using sodium (Na) Super Ion Conductors (NaSICON) membranes. The primary NaSICON compositions being investigated are based on rare- earth ions (RE-NaSICON). Potential applications include: caustic recycling for sludge leaching, regenerating ion exchange resins, inhibiting corrosion in carbon-steel tanks, or retrieving tank wastes; reducing the volume of low-level wastes volume to be disposed of; adjusting pH and reducing competing cations to enhance cesium ion exchange processes; reducing sodium in high-level-waste sludges; and removing sodium from acidic wastes to facilitate calcining. These applications encompass wastes stored at the Hanford, Savannah River, and Idaho National Engineering Laboratory sites. The overall project objective is to supply a salt splitting process unit that impacts the waste treatment and disposal flowsheets and meets user requirements. The potential flowsheet impacts include improving the efficiency of the waste pretreatment processes, reducing volume, and increasing the quality of the final waste disposal forms. Meeting user requirements implies developing the technology to the point where it is available as standard equipment with predictable and reliable performance. This report presents two preconceptual designs for a full-scale salt splitting process based on the RE-NaSICON membranes to distinguish critical items for testing and to provide a vision that site users can evaluate

  15. Quiz: What's the Buzz about Salt?

    Science.gov (United States)

    ... on. Feature: Too Much Salt Quiz: What's the buzz about salt? Past Issues / Spring - Summer 2010 Table ... Thing / Labels: For your health / Quiz: What's the buzz about salt? / Tasty Stand-Ins for Salt Spring / ...

  16. Design of Asymmetric Peptide Bilayer Membranes.

    Science.gov (United States)

    Li, Sha; Mehta, Anil K; Sidorov, Anton N; Orlando, Thomas M; Jiang, Zhigang; Anthony, Neil R; Lynn, David G

    2016-03-16

    Energetic insights emerging from the structural characterization of peptide cross-β assemblies have enabled the design and construction of robust asymmetric bilayer peptide membranes. Two peptides differing only in their N-terminal residue, phosphotyrosine vs lysine, coassemble as stacks of antiparallel β-sheets with precisely patterned charged lattices stabilizing the bilayer leaflet interface. Either homogeneous or mixed leaflet composition is possible, and both create nanotubes with dense negative external and positive internal solvent exposed surfaces. Cross-seeding peptide solutions with a preassembled peptide nanotube seed leads to domains of different leaflet architecture within single nanotubes. Architectural control over these cross-β assemblies, both across the bilayer membrane and along the nanotube length, provides access to highly ordered asymmetric membranes for the further construction of functional mesoscale assemblies.

  17. δ Meson Effects on Asymmetric Nuclear Matter

    Science.gov (United States)

    Liu, B.; di Toro, M.; Greco, V.

    The impact of a δ meson field (the scalar-isovector channel) on asymmetric nuclear matter is studied within relativistic mean-field (RMF) models with both constant and density dependent (DD) nucleon-meson couplings. The Equation of State (EOS) for asymmetric nuclear matter and the neutron star properties by the different models are compared. We find that the δ-field in the constant coupling scheme leads to a larger repulsion in dense neutron-rich matter and to a definite splitting of proton and neutron effective masses, finally influencing the stability of the neutron stars. A broader analysis of possible δ-field effects is achieved considering also density dependent nucleon-meson coupling. A remarkable effect on the relation between mass and radius for the neutron stars is seen, showing a significant reduction of the radius along with a moderate mass reduction due to the increase of the effective δ coupling in high density regions.

  18. Enhancing molecule fluorescence with asymmetrical plasmonic antennas.

    Science.gov (United States)

    Lu, Guowei; Liu, Jie; Zhang, Tianyue; Shen, Hongming; Perriat, Pascal; Martini, Matteo; Tillement, Olivier; Gu, Ying; He, Yingbo; Wang, Yuwei; Gong, Qihuang

    2013-07-21

    We propose and justify by the finite-difference time-domain method an efficient strategy to enhance the spontaneous emission of a fluorophore with a multi-resonance plasmonic antenna. The custom-designed asymmetrical antenna consists of two plasmonic nanoparticles with different sizes and is able to couple efficiently to free space light through multiple localized surface plasmon resonances. This design simultaneously permits a large near-field excitation near the antenna as well as a high quantum efficiency, which results in an unusual and significant enhancement of the fluorescence of a single emitter. Such an asymmetrical antenna presents intrinsic advantages over single particle or dimer based antennas made using two identical nanostructures. This promising concept can be exploited in the large domain of light-matter interaction processes involving multiple frequencies.

  19. Cosmological signatures of time-asymmetric gravity

    CERN Document Server

    Cortês, Marina; Smolin, Lee

    2016-01-01

    We develop the model proposed by Cort\\^es, Gomes & Smolin, to predict cosmological signatures of time-asymmetric extensions of general relativity they proposed recently. Within this class of models the equation of motion of chiral fermions is modified by a torsion term. This term leads to a dispersion law for neutrinos that associates a new time-varying energy with each particle. We find a new neutrino contribution to the Friedmann equation resulting from the torsion term in the Ashtekar connection. In this note we explore the phenomenology of this term and observational consequences for cosmological evolution. We show that constraints on the critical energy density will ordinarily render this term unobservably small, a maximum of order $10^{-25}$ of the neutrino energy density today. However, if the time-asymmetric dark energy is tuned to cancel the cosmological constant, the torsion effect may be a dark matter candidate.

  20. Asymmetric Electrodes Constructed with PAN-Based Activated Carbon Fiber in Capacitive Deionization

    Directory of Open Access Journals (Sweden)

    Mingzhe Li

    2014-01-01

    Full Text Available Capacitive deionization (CDI method has drawn much attention for its low energy consumption, low pollution, and convenient manipulation. Activated carbon fibers (ACFs possess high adsorption ability and can be used as CDI electrode material. Herein, two kinds of PAN-based ACFs with different specific surface area (SSA were used for the CDI electrodes. The CDI performance was investigated; especially asymmetric electrodes’ effect was evaluated. The results demonstrated that PAN-based ACFs showed a high electrosorption rate (complete electrosorption in less than half an hour and moderate electrosorption capacity (up to 0.2 mmol/g. CDI experiments with asymmetric electrodes displayed a variation in electrosorption capacity between forward voltage and reverse voltage. It can be attributed to the electrical double layer (EDL overlap effect and inner pore potential; thus the ions with smaller hydrated ionic radius can be adsorbed more easily.

  1. Moment methods for solving asymmetrically driven rf probes in the collisional ionospheric magnetoplasma

    International Nuclear Information System (INIS)

    The moment method is discussed, and the application of this method for solving asymmetrically driven RF probes in the collisional and warm ionospheric magnetoplasma is presented. The first three velocity moments of the Boltzmann transport equations are used for the description of the plasma. No interrelation between the electromagnetic mode and the plasma mode is assumed. The effects of these two modes on the antenna impedance are compared and it is shown that the electromagnetic effect is negligible with respect to the plasma effect under certain conditions. The absorptive boundary condition is considered so that the ion sheath may be treated as collapsed. Typical monopole, symmetrical dipole and asymmetrical dipole antennas are considered and many impedance curves are presented. Since the antenna impedance curves are related to all the plasma parameters, the methods of the prediction of plasma parameters from the measured antenna impedances are mentioned. Further research is proposed to eliminate the quasi-static restriction

  2. Applications of Chiral Anions in Asymmetric Catalysis

    OpenAIRE

    Hamilton, Gregory Lawrence

    2011-01-01

    The synthesis of molecules with control over their three-dimensional configuration, known as absolute stereochemistry, is one of the highest goals of synthetic organic chemists. As is so often the case, we strive to reach the facility and efficiency with which Nature achieves this goal. Fortunately, the chemist's imagination allows us to envision nearly unlimited possibilities for new modes of catalysis. In this dissertation, I discuss one branch of asymmetric catalysis that has in a short ti...

  3. New ruthenium catalysts for asymmetric hydrogenation

    OpenAIRE

    Diaz Valenzuela, Maria Belen

    2007-01-01

    A review on catalytic asymmetric hydrogenation of C=O double bonds is presented in the first chapter. Noyori’s pioneering research on ruthenium complexes containing both phosphine and diamine ligands using [i superscript]PrOH and [t superscript]BuOK is described, this system gave impressive highly chemeo-selectivity for C=O bonds and extremely high enantioselectivity for a range of acetophenone derivatives. Numerous groups have been inspired by Noyori’s catalyst of the ty...

  4. Competitive Price and Quality Under Asymmetric Information

    OpenAIRE

    Gerard J. Tellis; Birger Wernerfelt

    1987-01-01

    We present an analysis of equilibrium in markets with asymmetrically informed consumers. Some consumers know both price and quality of all sellers, whereas others know neither but may search among sellers. The equilibrium correlation between price and quality generally increases with the level of information in the market and can be negative when this level is sufficiently small. A meta-analysis of the available empirical studies strongly supports the model's predictions.

  5. Cosmological signatures of time-asymmetric gravity

    OpenAIRE

    Cortês, Marina; Liddle, Andrew R; Smolin, Lee

    2016-01-01

    We develop the model proposed by Cort\\^es, Gomes & Smolin, to predict cosmological signatures of time-asymmetric extensions of general relativity they proposed recently. Within this class of models the equation of motion of chiral fermions is modified by a torsion term. This term leads to a dispersion law for neutrinos that associates a new time-varying energy with each particle. We find a new neutrino contribution to the Friedmann equation resulting from the torsion term in the Ashtekar conn...

  6. Asymmetric inheritance of cytoophidia in Schizosaccharomyces pombe

    OpenAIRE

    Jing Zhang; Lydia Hulme; Ji-Long Liu

    2014-01-01

    ABSTRACT A general view is that Schizosaccharomyces pombe undergoes symmetric cell division with two daughter cells inheriting equal shares of the content from the mother cell. Here we show that CTP synthase, a metabolic enzyme responsible for the de novo synthesis of the nucleotide CTP, can form filamentous cytoophidia in the cytoplasm and nucleus of S. pombe cells. Surprisingly, we observe that both cytoplasmic and nuclear cytoophidia are asymmetrically inherited during cell division. Our t...

  7. Selective Homogeneous Catalysis in Asymmetric Synthesis

    DEFF Research Database (Denmark)

    Fristrup, Peter

    The subject of this thesis is selectivity in homogeneous asymmetric transition metalcatalyzed reactions. Four different reactions within organic chemistry have been studied by kinetic measurements, computational chemistry (modelling) or both of them in parallel. A Hammett study was performed....... A thorough computational study succeeded in explaining the observed results, although other significant results were also obtained during this study. Finally, an intramolecular reaction was studied computationally, and the rate increase observed under phase transfer catalysis conditions could be related...

  8. On asymmetric collisions with large disruption parameters

    International Nuclear Information System (INIS)

    Collisions between a weak electron bunch and a strong positron bunch are studied within a flat model. Electrons are tracked through the transverse space charge field of the positron bunch, and it is shown that positrons in a storage ring may remain stable after asymmetric collisions with a weak electron bunch in spite of large values of the electron disruption parameter. The plasma oscillations that affect collisions with large disruption parameters may be suppressed by properly matching the electrons. 8 refs., 5 figs

  9. Surface segregation of conformationally asymmetric polymer blends

    OpenAIRE

    Stepanow, Semjon; Fedorenko, Andrei A.

    2005-01-01

    We have generalized the Edwards' method of collective description of dense polymer systems in terms of effective potentials to polymer blends in the presence of a surface. With this method we have studied conformationally asymmetric athermic polymer blends in the presence of a hard wall to the first order in effective potentials. For polymers with the same gyration radius $R_g$ but different statistical segment lengths $l_{A}$ and $l_{B}$ the excess concentration of stiffer polymers at the su...

  10. Neuronal alignment on asymmetric textured surfaces

    OpenAIRE

    Beighley, Ross; Spedden, Elise; Sekeroglu, Koray; Atherton, Timothy; Demirel, Melik C.; Staii, Cristian

    2012-01-01

    Axonal growth and the formation of synaptic connections are key steps in the development of the nervous system. Here, we present experimental and theoretical results on axonal growth and interconnectivity in order to elucidate some of the basic rules that neuronal cells use for functional connections with one another. We demonstrate that a unidirectional nanotextured surface can bias axonal growth. We perform a systematic investigation of neuronal processes on asymmetric surfaces and quantify...

  11. Trapdoor Privacy in Asymmetric Searchable Encryption Schemes

    OpenAIRE

    Delerue Arriaga, Afonso; TANG, QIANG; Ryan, Peter

    2014-01-01

    Asymmetric searchable encryption allows searches to be carried over ciphertexts, through delegation, and by means of trapdoors issued by the owner of the data. Public Key Encryption with Keyword Search (PEKS) is a primitive with such functionality that provides delegation of exact-match searches. As it is important that ciphertexts preserve data privacy, it is also important that trapdoors do not expose the user’s search criteria. The difficulty of formalizing a security model for trapdoor pr...

  12. Legal Dilemmas in Fighting Asymmetrical Conflicts

    Directory of Open Access Journals (Sweden)

    Pnina Sharvit Baruch

    2012-04-01

    Full Text Available What legal rules apply to armed confrontations against non-state elements in areas populated by civilians? What rules apply when the enemy does not honor the basic laws of warfare - does not distinguish itself from the local population, and even uses it for shelter and as a base of operations? This essay, which presents my position on the issue, refers to such confrontations as "asymmetrical conflicts."

  13. Do Daily Retail Gasoline Prices adjust Asymmetrically?

    OpenAIRE

    Bettendorf, Leon; Geest, Stéphanie; Kuper, G.

    2005-01-01

    This paper analyzes adjustments in the Dutch retail gasoline prices. We estimate an error correction model on changes in the daily retail price for gasoline (taxes excluded) for the period 1996-2004 taking care of volatility clustering by estimating an EGARCH model. It turns out the volatility process is asymmetrical: an unexpected increase in the producer price has a larger effect on the variance of the producer price than an unexpected decrease. We do not find evidence for amount asymmetry,...

  14. Asymmetric Information – Adverse Selection Problem

    Directory of Open Access Journals (Sweden)

    Dumitru MARIN

    2007-01-01

    Full Text Available The present paper makes an introduction in the contract theory starting with the definitions of asymmetric information and some of the problems that generate: moral hazard and adverse selection. We provide an insight of the latest empirical studies in adverse selection in different markets. An adverse selection model, based on Rothchild and Stiglitz is also present to give a perspective of the theoretical framework.

  15. OFFICER AND COMMANDER IN ASYMMETRIC WARFARE OPERATIONS

    OpenAIRE

    Giuseppe CAFORIO

    2013-01-01

    Starting from the data of a field research conducted among soldiers with asymmetric warfare experiences from nine different countries, the author seeks to identify and shed light on the various problems that officers with command responsibilities had to face during their missions. A picture emerges of feelings and experiences relating to their first impression upon arriving in the theatre, relations with local armed forces, relations with the local population and local authorities, relations ...

  16. Ultralong distance coupling between asymmetric resonant microcavities

    OpenAIRE

    Shu, Fang-Jie; Zou, Chang-Ling; Chen, Wen-Cong; Sun, Fang-Wen

    2013-01-01

    The ultralong distance coupling between two Asymmetric Resonant Microcavities (ARCs) is studied. Different from traditional short distance tunneling coupling between microcavities, the high efficient free space directional emission and excitation allow ultralong distance energy transfer between ARCs. In this paper, a novel unidirectional emission ARC, which shows directionality I40 = 0.54, is designed for materials of refractive index n = 2.0. Compared with regular whispering gallery microres...

  17. Prospects for Asymmetric PNe with ALMA

    CERN Document Server

    Huggins, P J

    2010-01-01

    Millimeter and sub-millimeter observations have made fundamental contributions to our current understanding of the transition from AGB stars to white dwarfs. The approaching era of ALMA brings significantly enhanced observing capabilities at these wavelengths and promises to push back the frontiers in a number of ways. We examine the scientific prospects of this new era for PNe, with an emphasis on how developments may contribute to the goals of the asymmetric PNe community.

  18. Asymmetric Reversal in Inhomogeneous Magnetic Heterostructures

    OpenAIRE

    Li, Zhi-Pan; Petracic, Oleg; Morales, Rafael; Olamit, Justin; Batlle, Xavier; Liu, Kai; Schuller, Ivan K.

    2006-01-01

    Asymmetric magnetization reversal is an unusual phenomenon in antiferromagnet/ferromagnet (AF/FM) exchange biased bilayers. We investigated this phenomenon in a simple model system experimentally and by simulation assuming inhomogeneously distributed interfacial AF moments. The results suggest that the observed asymmetry originates from the intrinsic broken symmetry of the system, which results in local incomplete domain walls parallel to the interface in reversal to negative saturation of th...

  19. Novel Electrolytes for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lucht, Brett L

    2014-12-12

    We have been investigating three primary areas related to lithium ion battery electrolytes. First, we have been investigating the thermal stability of novel electrolytes for lithium ion batteries, in particular borate based salts. Second, we have been investigating novel additives to improve the calendar life of lithium ion batteries. Third, we have been investigating the thermal decomposition reactions of electrolytes for lithium-oxygen batteries.

  20. Evaluation of Salt Removal from Azulejo Tiles and Mortars using Electrodesalination

    DEFF Research Database (Denmark)

    Ferreira, Célia Maria Dias; Ottosen, Lisbeth M.; Christensen, Iben Vernegren;

    2011-01-01

    loss of historic value. In this work preliminary studies with single tiles presenting an underlying layer of mortar have been conducted to assess the amount of salts that can be removed from the building material using a new technique called “electrodesalination”, in which the salt’s ions...... and underlying mortar are no longer at risk of salt induced decay. The main conclusions are that the technique is successful in extracting salts from mortars (removals efficiencies between 88% and 92%) but not as good for the tile (removals between 10% and 80%). The risk of salt damage to the mortar and tile...

  1. Asymmetric Conditional Volatility in International Stock Markets

    CERN Document Server

    Ferreira, N B; Menezes, R; Ferreira, Nuno B.; Mendes, Diana A.; Menezes, Rui

    2006-01-01

    Recent studies show that a negative shock in stock prices will generate more volatility than a positive shock of similar magnitude. The aim of this paper is to appraise the hypothesis under which the conditional mean and the conditional variance of stock returns are asymmetric functions of past information. We compare the results for the Portuguese Stock Market Index PSI 20 with six other Stock Market Indices, namely the S&P 500, FTSE100, DAX 30, CAC 40, ASE 20, and IBEX 35. In order to assess asymmetric volatility we use autoregressive conditional heteroskedasticity specifications known as TARCH and EGARCH. We also test for asymmetry after controlling for the effect of macroeconomic factors on stock market returns using TAR and M-TAR specifications within a VAR framework. Our results show that the conditional variance is an asymmetric function of past innovations raising proportionately more during market declines, a phenomenon known as the leverage effect. However, when we control for the effect of chan...

  2. Asymmetric nuclear matter equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Bombaci, I.; Lombardo, U. (Dipartimento di Fisica, Universita di Catania, Corso Italia 57, Catania (Italy) Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia 57, I-95129 Catania (Italy))

    1991-11-01

    Systematic calculations of asymmetric nuclear matter have been performed in the framework of the Brueckner-Bethe-Goldstone approach in a wide range of both density and asymmetry parameter. The empirical parabolic law fulfilled by the binding energy per nucleon is confirmed by the present results in all the range of the asymmetry parameter values. The predominant role of the {sup 3}{ital S}{sub 1-}{sup 3}{ital D}{sub 1} component of the {ital NN} interaction is elucidated. A linear variation of the proton and neutron single-particle potentials is found as increasing the neutron excess; a deviation from the phenomenological potentials occurs for highly asymmetric matter as an effect of the self-consistency. The present calculations of the incompressibility predict a strong softening of the equation of state going from symmetric to asymmetric nuclear matter. The proton fraction in equilibrium with neutron matter has been determined from the beta-stability condition and its relevance to the superfluidity of neutron stars has been investigated.

  3. Multiple Traveling Salesmen in Asymmetric Metrics

    CERN Document Server

    Friggstad, Zachary

    2011-01-01

    We consider some generalizations of the Asymmetric Traveling Salesman Path problem. Suppose we have an asymmetric metric G = (V,A) with two distinguished nodes s,t. We are also given a positive integer k. The goal is to find k paths of minimum total cost from s to t whose union spans all nodes. We call this the k-Person Asymmetric Traveling Salesmen Path problem (k-ATSPP). Our main result for k-ATSPP is a bicriteria approximation that, for some parameter b >= 1 we may choose, finds between k and k + k/b paths of total length O(b log |V|) times the optimum value of an LP relaxation based on the Held-Karp relaxation for the Traveling Salesman problem. On one extreme this is an O(log |V|)-approximation that uses up to 2k paths and on the other it is an O(k log |V|)-approximation that uses exactly k paths. Next, we consider the case where we have k pairs of nodes (s_1,t_1), ..., (s_k,t_k). The goal is to find an s_i-t_i path for every pair such that each node of G lies on at least one of these paths. Simple appro...

  4. Asymmetric threat data mining and knowledge discovery

    Science.gov (United States)

    Gilmore, John F.; Pagels, Michael A.; Palk, Justin

    2001-03-01

    Asymmetric threats differ from the conventional force-on- force military encounters that the Defense Department has historically been trained to engage. Terrorism by its nature is now an operational activity that is neither easily detected or countered as its very existence depends on small covert attacks exploiting the element of surprise. But terrorism does have defined forms, motivations, tactics and organizational structure. Exploiting a terrorism taxonomy provides the opportunity to discover and assess knowledge of terrorist operations. This paper describes the Asymmetric Threat Terrorist Assessment, Countering, and Knowledge (ATTACK) system. ATTACK has been developed to (a) data mine open source intelligence (OSINT) information from web-based newspaper sources, video news web casts, and actual terrorist web sites, (b) evaluate this information against a terrorism taxonomy, (c) exploit country/region specific social, economic, political, and religious knowledge, and (d) discover and predict potential terrorist activities and association links. Details of the asymmetric threat structure and the ATTACK system architecture are presented with results of an actual terrorist data mining and knowledge discovery test case shown.

  5. Traceless Synthesis of Asymmetrically Modified Bivalent Nucleosomes.

    Science.gov (United States)

    Lechner, Carolin C; Agashe, Ninad D; Fierz, Beat

    2016-02-18

    Nucleosomes carry extensive post-translational modifications (PTMs), which results in complex modification patterns that are involved in epigenetic signaling. Although two copies of each histone coexist in a nucleosome, they may not carry the same PTMs and are often differently modified (asymmetric). In bivalent domains, a chromatin signature prevalent in embryonic stem cells (ESCs), namely H3 methylated at lysine 4 (H3K4me3), coexists with H3K27me3 in asymmetric nucleosomes. We report a general, modular, and traceless method for producing asymmetrically modified nucleosomes. We further show that in bivalent nucleosomes, H3K4me3 inhibits the activity of the H3K27-specific lysine methyltransferase (KMT) polycomb repressive complex 2 (PRC2) solely on the same histone tail, whereas H3K27me3 stimulates PRC2 activity across tails, thereby partially overriding the H3K4me3-mediated repressive effect. To maintain bivalent domains in ESCs, PRC2 activity must thus be locally restricted or reversed.

  6. Mixed salt crystallisation fouling

    CERN Document Server

    Helalizadeh, A

    2002-01-01

    The main purpose of this investigation was to study the mechanisms of mixed salt crystallisation fouling on heat transfer surfaces during convective heat transfer and sub-cooled flow boiling conditions. To-date no investigations on the effects of operating parameters on the deposition of mixtures of calcium sulphate and calcium carbonate, which are the most common constituents of scales formed on heat transfer surfaces, have been reported. As part of this research project, a substantial number of experiments were performed to determine the mechanisms controlling deposition. Fluid velocity, heat flux, surface and bulk temperatures, concentration of the solution, ionic strength, pressure and heat transfer surface material were varied systematically. After clarification of the effect of these parameters on the deposition process, the results of these experiments were used to develop a mechanistic model for prediction of fouling resistances, caused by crystallisation of mixed salts, under convective heat transfer...

  7. Frost formation with salt

    OpenAIRE

    Guadarrama-Cetina, J.; Mongruel, A. (Anne); González-Viñas, W.; Beysens, D.A. (Daniel A.)

    2015-01-01

    The formation of frost in presence of salt (NaCl) crystal is experimentally investigated on a hydrophobic surface. It presents several remarkable features due to the interplay of salty-water saturation pressure evolution, initially lower than the saturation pressure of ice and water, and the percolating propagation of ice dendrites from defects throughout the supercooled water droplet pattern. In particular, it is remarkable that nucleation of supercooled water and/or ice is prevented around ...

  8. Effects of salt concentration and pH value on ion rectification of conical glass nanopore%锥形玻璃纳米孔中溶液浓度和pH值对整流的影响

    Institute of Scientific and Technical Information of China (English)

    黄玉华; 葛艳艳; 沙菁洁; 刘磊; 章寅; 陈云飞

    2014-01-01

    In order to explore the mechanism of the conical nanopore rectification,glass conical nan-opores were fabricated with boron silicate glass capillary on micropipette puller system P 2000.The nanopores' diameter ranged from 20 to 50 nm.After the pore was filled with sodium chloride solu-tion,the rectification effect of the pore was experimentally studied with a patch clamp.It is found that the rectification ratio of the nanopore shows an increase and then decrease trend as the solution concentration becomes higher,and the highest rectification ratio appears when the salt concentration is between 10 and 50 mmol/L.When the pH is above the isoelectric point of glass,the rectification ratio increases as the solution pH increases.When the pH is below the isoelectric point of glass,the surface of the glass exhibits charge inversion and the rectification direction changes.The results show that conical nanopore rectification can be influenced both by salt concentration and pH value,and charge inversion can occur on the surface of glass without any chemical modification.%为了探索锥形纳米孔整流的机理,以硼硅酸盐玻璃毛细管为材料,采用微电极拉制仪P 2000拉制了内径20~50 nm的玻璃锥形纳米孔。孔内注满氯化钠盐溶液后,采用膜片钳对该类纳米孔的整流效应进行了实验研究。实验发现,锥形玻璃纳米孔的整流比随浓度先增大后减小,在溶液浓度为10~50 mmol/L范围内出现最大整流比。当溶液pH值高于玻璃等电点时,随着溶液pH值的增大,整流比随之增大;当溶液pH值低于玻璃等电点时,玻璃表面发生壁面电荷倒置,整流方向发生改变。实验结果表明,玻璃锥形纳米孔整流效应受到溶液浓度和溶液pH值共同影响,纳米孔内壁不经过任何化学修饰就可以发生电荷倒置。

  9. Simulations of Cyclic Voltammetry for Electric Double Layers in Asymmetric Electrolytes: A Generalized Modified Poisson-Nernst-Planck Model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hainan; Thiele, Alexander; Pilon, Laurent [UCLA

    2013-11-15

    This paper presents a generalized modified Poisson–Nernst–Planck (MPNP) model derived from first principles based on excess chemical potential and Langmuir activity coefficient to simulate electric double-layer dynamics in asymmetric electrolytes. The model accounts simultaneously for (1) asymmetric electrolytes with (2) multiple ion species, (3) finite ion sizes, and (4) Stern and diffuse layers along with Ohmic potential drop in the electrode. It was used to simulate cyclic voltammetry (CV) measurements for binary asymmetric electrolytes. The results demonstrated that the current density increased significantly with decreasing ion diameter and/or increasing valency |zi| of either ion species. By contrast, the ion diffusion coefficients affected the CV curves and capacitance only at large scan rates. Dimensional analysis was also performed, and 11 dimensionless numbers were identified to govern the CV measurements of the electric double layer in binary asymmetric electrolytes between two identical planar electrodes of finite thickness. A self-similar behavior was identified for the electric double-layer integral capacitance estimated from CV measurement simulations. Two regimes were identified by comparing the half cycle period τCV and the “RC time scale” τRC corresponding to the characteristic time of ions’ electrodiffusion. For τRC ← τCV, quasi-equilibrium conditions prevailed and the capacitance was diffusion-independent while for τRC → τCV, the capacitance was diffusion-limited. The effect of the electrode was captured by the dimensionless electrode electrical conductivity representing the ratio of characteristic times associated with charge transport in the electrolyte and that in the electrode. The model developed here will be useful for simulating and designing various practical electrochemical, colloidal, and biological systems for a wide range of applications.

  10. Transcriptional Regulation of Arabidopsis in Response to Salt Stress

    Institute of Scientific and Technical Information of China (English)

    Zhulong Chan

    2012-01-01

    Salt stress is a major factor limiting agricultural productivity worldwide.Adaptations to salt stress include avoidance by reduced sodium uptake,sequestration of toxic sodium ions away from the cytoplasm,or production of compatible solutes or osmoprotectants to reduce molecular disruption.Approaches to engineer salt stress resistance have included regulation of ion transport through introduction of Na+/H+ antiporter; synthesis of compatible solutes; or the introduction of transcription factors regulating expression of stress-responsive genes.On the other hand,naturally occurring variation among wild-type populations of plants also can be used to understand plant adaptive responses to their environments.In this study,we compared phenotypic and transcriptomic effects of constitutive expression of genes intended to confer salt stress tolerance by three different mechanisms:a transcription factor,CBF3/DREB1a; a metabolic gene,M6PR,for mannitol biosynthesis; and the Na+/H+ antiporter,SOS1.In the absence of salt,M6PR and SOS1 lines performed comparably with wild type; CBF3 lines exhibited dwarfing as reported previously.All three transgenes conferred fitness advantage when subjected to 100 mmol/L NaCI in the growth chamber.CBF3 and M6PR affected transcription of numerous abiotic stress-related genes as measured by Affymetrix microarray analysis.M6PR additionally modified expression of biotic stress and oxidative stress genes.Transcriptional effects of SOS1 were smaller and primarily limited to redox-related genes.In addition,we compared natural variations in salt tolerance between Ler and Sha ecotypes based on their responses to salt treatments and the results indicated that Ler was salt-sensitive,but Sha,which obtained a truncated RAS1 protein,was salt-tolerant.Transcriptome analysis revealed that many genes involved in secondary metabolism,photosynthesis,and protein synthesis were mainly down-regulated by salinity effects,while transposable element genes,microRNA and

  11. Preparation and Characterization of Amino Acids-Based Trimethoprim Salts

    Directory of Open Access Journals (Sweden)

    Afzal R. Mohammed

    2012-02-01

    Full Text Available Trimethoprim (TMP is a dihydrofolate reductase (DHFR inhibitor which prevents the conversion of dihydrofolic acid into tetrahydrofolic acid, resulting in the depletion of the latter and leading to bacterial death. Oral bioavailability of TMP is hindered by both its low solubility and low permeability. This study aims to prepare novel salts of TMP using anionic amino acids; aspartic and glutamic acid as counter ions in order to improve solubility and dissolution. TMP salts were prepared by lyophilisation and characterized using FT-IR spectroscopy, proton nuclear magnetic resonance (1HNMR, Differential Scanning Calorimetry (DSC and Thermogravimetric analysis (TGA. Both the amino acids formed salts with TMP in a 1:1 molar ratio and showed a 280 fold improvement in solubility. Investigation of the microbiological activity of the prepared salts against TMP sensitive Escherichia coli showed that the new salts not only retained antibacterial activity but also exhibited higher zone of inhibition which was attributed to improved physicochemical characters such as higher solubility and dissolution. The results are an important finding that could potentially impact on faster onset of antibacterial activity and reduced therapeutic dose when administered to patients. Studies are underway investigating the effect of ion-pairing TMP with amino acids on the permeability profile of the drug.

  12. Solution Asymmetry and Salt Expand Fluid-Fluid Coexistence Regions of Charged Membranes.

    Science.gov (United States)

    Kubsch, Bastian; Robinson, Tom; Lipowsky, Reinhard; Dimova, Rumiana

    2016-06-21

    Liquid-liquid phase separation in giant unilamellar vesicles (GUVs) leads to the formation of intramembrane domains. To mimic charged biological membranes, we studied phase separation and domain formation in GUVs of ternary lipid mixtures composed of egg sphingomyelin, cholesterol, and the negatively charged lipid dioleoylphosphatidylglycerol. The GUVs were exposed to solutions of sucrose and high-saline buffer. The phase diagram was determined using epifluorescence microscopy for vesicle populations with symmetric and asymmetric solution compositions across the membranes. Trans-membrane solution asymmetry was found to affect the membrane phase state. Furthermore, compared to the case of salt-free conditions, the phase diagram in the presence of high-saline buffer (both symmetrically or asymmetrically present across the membrane) was found to exhibit a significantly extended region of liquid-ordered and liquid-disordered coexistence. These observations were confirmed on single GUVs using microfluidics and confocal microscopy. Moreover, we found that the miscibility temperatures markedly increased for vesicles in the presence of symmetric and asymmetric salt solutions. Our results demonstrate a substantial effect of salt and solution asymmetry on the phase behavior of charged membranes, which has direct implications for protein adsorption onto these membranes and for the repartitioning of proteins within the membrane domains. PMID:27288275

  13. Ion Pairing in Alkali Nitrate Electrolyte Solutions.

    Science.gov (United States)

    Xie, Wen Jun; Zhang, Zhen; Gao, Yi Qin

    2016-03-10

    In this study, we investigate the thermodynamics of alkali nitrate salt solutions, especially the formation of contact ion pairs between alkali cation and nitrate anion. The ion-pairing propensity shows an order of LiNO3 law of matching water affinity" is followed by these alkali nitrate salt solutions. The spatial patterns of contact ion pairs are different in the three salt solutions studied here: Li(+) forms the contact ion pair with only one oxygen of the nitrate while Na(+) and K(+) can also be shared by two oxygens of the nitrate. In reproducing the salt activity coefficient using Kirkwood-Buff theory, we find that it is essential to include electronic polarization for Li(+) which has a high charge density. The electronic continuum correction for nonpolarizable force field significantly improves the agreement between the calculated activity coefficients and their experimental values. This approach also improves the performance of the force field on salt solubility. From these two aspects, this study suggests that electronic continuum correction can be a promising approach to force-field development for ions with high charge densities. PMID:26901167

  14. Ion Pairing in Alkali Nitrate Electrolyte Solutions.

    Science.gov (United States)

    Xie, Wen Jun; Zhang, Zhen; Gao, Yi Qin

    2016-03-10

    In this study, we investigate the thermodynamics of alkali nitrate salt solutions, especially the formation of contact ion pairs between alkali cation and nitrate anion. The ion-pairing propensity shows an order of LiNO3 activity coefficients and suggest that the empirical "law of matching water affinity" is followed by these alkali nitrate salt solutions. The spatial patterns of contact ion pairs are different in the three salt solutions studied here: Li(+) forms the contact ion pair with only one oxygen of the nitrate while Na(+) and K(+) can also be shared by two oxygens of the nitrate. In reproducing the salt activity coefficient using Kirkwood-Buff theory, we find that it is essential to include electronic polarization for Li(+) which has a high charge density. The electronic continuum correction for nonpolarizable force field significantly improves the agreement between the calculated activity coefficients and their experimental values. This approach also improves the performance of the force field on salt solubility. From these two aspects, this study suggests that electronic continuum correction can be a promising approach to force-field development for ions with high charge densities.

  15. NOx emissions and NO2- formation in thermal energy storage process of binary molten nitrate salts

    International Nuclear Information System (INIS)

    Referring to the national environmental protection standard of PR China, HJ479-2009, NOx emissions and the effect of 45# carbon steel (1045, ASTM) on it in thermal energy storage (TES) process of binary molten nitrate (BMN) salts (a eutectic salt mixture named as solar salt with the component of 60% NaNO3 and 40% KNO3) are discussed in this paper. The accumulative absorption concentrations of NOx emissions in tail gases of molten salts heated at different temperatures were measured to study the thermal decomposition situation of molten salts in TES process. Furthermore, the concentrations of nitrite ion in molten salts samples were determined and chemical thermodynamic calculations of related reactions were done to explain the results. The research shows that BMN salts contained in silica or carbon steel container in the air under certain conditions can release NOx in its use of temperature range. The concentrations of NOx emissions and nitrite ion in molten salts both increase with the rise of the temperature. After contacting with 45# carbon steel, the total concentrations of NOx emissions and nitrite ion in molten salts increased, which may be caused by Fe component in the carbon steel. - Highlights: • NOx emissions in TES process of binary molten nitrate salts are discussed. • The effect of 45# carbon steel on NOx emissions was also studied. • The concentrations of NOx emissions increase with the rise of the temperature. • The concentrations of nitrite ion creep with increasing temperature. • Fe element in the carbon steel may result in the increment of NO emissions

  16. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    OpenAIRE

    Nielsen, Christoffer Peder; Bruus, Henrik

    2013-01-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in qualitative agreement with experimental results published in the literature. The analytical results are furthermore in agreement with direct numerical simulations. As part of the analysis, we find app...

  17. Dynamics of salt playa polygons

    Science.gov (United States)

    Goehring, L.; Fourrière, A.

    2014-12-01

    In natural salt playa or in evaporation pools for the salt extraction industry, one can sometimes see surprising regular structures formed by ridges of salt. These ridges connect together to form a self-organized network of polygons one to two meters in diameter, which we call salt polygons. Here we propose a mechanism based on porous media convection of salty water in soil to explain the formation and the scaling of the salt polygons. Surface evaporation causes a steady upward flow of salty water, which can cause precipitation near the surface. A vertical salt gradient then builds up in the porous soil, with heavy salt-saturated water lying over the less salty source water. This can drive convection when a threshold is reached, given by a critical Rayleigh number of about 7. We suggest that the salt polygons are the surface expression of the porous medium convection, with salt crystallizing along the positions of the convective downwellings. To study this instability directly, we developed a 2D analogue experiment using a Hele-Shaw cell filled with a porous medium saturated with a salt solution and heated from above. We perform a linear stability analysis of this system, and find that it is unstable to convection, with a most unstable wavelength that is set by a balance between salt diffusion and water evaporation. The Rayleigh number in our experiment is controlled by the particle size of our model soil, and the evaporation rate. We obtain results that scale with the observation of natural salt polygons. Using dye, we observe the convective movement of salty water and find downwelling convective plumes underneath the spots where surface salt ridges form, as shown in the attached figure.

  18. Zinc oxide nanoring embedded lacey graphene nanoribbons in symmetric/asymmetric electrochemical capacitive energy storage

    Science.gov (United States)

    Sahu, Vikrant; Goel, Shubhra; Sharma, Raj Kishore; Singh, Gurmeet

    2015-12-01

    This article describes the synthesis and characterization of ZnO nanoring embedded graphene nanoribbons. Patterned holes (mesopore dia.) in graphene nanoribbons are chemically generated, leading to a high density of the edge planes. These planes carry negatively charged surface groups (like -COOH and -OH) and therefore anchor the metal ions in a cordial fashion forming a string of metal ions along the edge planes. These strings of imbibed metal ions precipitate as tiny ZnO nanorings over lacey graphene nanoribbons. The thus obtained graphene nanoribbon (GNR) based hierarchical ZnO mesoporous structures are three dimensionally accessible to the electrolyte and demonstrate high performance in capacitive energy storage. The ZnO/GNR nanocomposite electrode in an asymmetric supercapacitor device with lacey reduced graphene oxide nanoribbons (LRGONRs) as a negative electrode exhibits a 2.0 V potential window in the aqueous electrolyte and an ultra-short time constant (0.08 s). The wide potential window consequently increased the energy density from 6.8 Wh kg-1 (ZnO/GNR symmetric) to 9.4 Wh kg-1 (ZnO/GNR||LRGONR asymmetric). The relaxation time constant obtained for the asymmetric supercapacitor device was three orders of magnitude less compared to the ZnO (symmetric, 33 s) supercapacitor device. The high cycling stability of ZnO/GNR||LRGONR up to 96.7% capacitance retention, after 5000 GCD cycles at 2 mA cm-2, paves the way to a high performance aqueous electrochemical supercapacitive energy storage.This article describes the synthesis and characterization of ZnO nanoring embedded graphene nanoribbons. Patterned holes (mesopore dia.) in graphene nanoribbons are chemically generated, leading to a high density of the edge planes. These planes carry negatively charged surface groups (like -COOH and -OH) and therefore anchor the metal ions in a cordial fashion forming a string of metal ions along the edge planes. These strings of imbibed metal ions precipitate as tiny Zn

  19. Anabaena sp. DyP-type peroxidase is a tetramer consisting of two asymmetric dimers.

    Science.gov (United States)

    Yoshida, Toru; Ogola, Henry Joseph Oduor; Amano, Yoshimi; Hisabori, Toru; Ashida, Hiroyuki; Sawa, Yoshihiro; Tsuge, Hideaki; Sugano, Yasushi

    2016-01-01

    DyP-type peroxidases are a newly discovered family of heme peroxidases distributed from prokaryotes to eukaryotes. Recently, using a structure-based sequence alignment, we proposed the new classes, P, I and V, as substitutes for classes A, B, C, and D [Arch Biochem Biophys 2015;574:49-55]. Although many class V enzymes from eukaryotes have been characterized, only two from prokaryotes have been reported. Here, we show the crystal structure of one of these two enzymes, Anabaena sp. DyP-type peroxidase (AnaPX). AnaPX is tetramer formed from Cys224-Cys224 disulfide-linked dimers. The tetramer of wild-type AnaPX was stable at all salt concentrations tested. In contrast, the C224A mutant showed salt concentration-dependent oligomeric states: in 600 mM NaCl, it maintained a tetrameric structure, whereas in the absence of salt, it dissociated into monomers, leading to a reduction in thermostability. Although the tetramer exhibits non-crystallographic, 2-fold symmetry in the asymmetric unit, two subunits forming the Cys224-Cys224 disulfide-linked dimer are related by 165° rotation. This asymmetry creates an opening to cavities facing the inside of the tetramer, providing a pathway for hydrogen peroxide access. Finally, a phylogenetic analysis using structure-based sequence alignments showed that class V enzymes from prokaryotes, including AnaPX, are phylogenetically closely related to class V enzymes from eukaryotes.

  20. Effects of Hofmeister salt series on gluten network formation: Part I. Cation series.

    Science.gov (United States)

    Tuhumury, H C D; Small, D M; Day, L

    2016-12-01

    Different cationic salts were used to investigate the effects of the Hofmeister salt series on gluten network formation. The effects of cationic salts on wheat flour dough mixing properties, the rheological and the chemical properties of the gluten extracted from the dough with different respective salts, were investigated. The specific influence of different cationic salts on the gluten structure formation during dough mixing, compared to the sodium ion, were determined. The effects of different cations on dough and gluten of different flours mostly followed the Hofmeister series (NH4(+), K(+), Na(+), Mg(2+) and Ca(2+)). The impacts of cations on gluten structure and dough rheology at levels tested were relatively small. Therefore, the replacement of sodium from a technological standpoint is possible, particularly by monovalent cations such as NH4(+), or K(+). However the levels of replacement need to take into account sensory attributes of the cationic salts. PMID:27374596

  1. Investigating bile salt aggregation using coarse-grained molecular dynamics simulations

    Science.gov (United States)

    Vila Verde, Ana; Frenkel, Daan

    2010-03-01

    Bile salts are necessary for fat digestion due to their unusual surfactant properties: they assemble into small, polydisperse micelles and easily form mixed micelles with poorly soluble amphiphiles. Understanding these properties requires molecular scale information about bile salt micelles, something challenging to obtain experimentally but amenable to computational modeling. To address this issue we build a coarse-grained model of bile salts. We investigate their aggregation behavior through molecular dynamics simulations in a grand-canonical parallel tempering scheme. We validate our model against available solubility and light scattering data. Our results indicate that at physiological bile salt and counter ion concentrations, bile salts pack in many different orientations in pure bile micelles, contrary to standard surfactants. This feature may be physiologically relevant, allowing bile salts to solubilize the heterogeneous blends of fats typical of digestion.

  2. Reactive halogen species above salt lakes and salt pans

    OpenAIRE

    Holla, Robert

    2013-01-01

    Salt lakes can be found on all continents and saline soils cover 2.5% of the land surface of the earth (FAO, 2012). This thesis investigates the presence of reactive halogen species (RHS) above salt lakes and saline soils to evaluate their relevance for tropospheric chemistry of the planetary boundary layer. Ground-based MAX-DOAS and LP-DOAS measurements were conducted at salt lakes and two other sites with high halogen content. Prior to this work, RHS were found at three salt ...

  3. Assessing the soil microbial carbon budget: Probing with salt stress

    Science.gov (United States)

    Rath, Kristin; Rousk, Johannes

    2014-05-01

    measures are more sensitive to salinity than catabolic processes. This could be an indication that at higher salt concentrations, the microbial community allocates less carbon towards growth, resulting in reduced carbon use efficiency. We also found that microbial processes show different sensitivities depending on the kind of salt used in the experiment. Currently we are making comparative analyses to determine whether osmotic strength or specific ion concentrations best explain toxicity. In addition we are in the process of investigating if pre-exposed communities from naturally saline soils have developed a higher tolerance to salt.

  4. Ion permeable microcapsules for the release of biologically available ions for remineralization.

    Science.gov (United States)

    Davidson, Michael T; Greving, Theresa A; McHale, William A; Latta, Mark A; Gross, Stephen M

    2012-03-01

    The objective of this study was to investigate the effect of chemical structure, ion concentration, and ion type on the release rate of biologically available ions useful for remineralization from microcapsules with ion permeable membranes. A heterogeneous polymerization technique was utilized to prepare microcapsules containing either an aqueous solution of K₂HPO₄, Ca(NO₃)₂, or NaF. Six different polyurethane-based microcapsule shells were prepared and characterized based on ethylene glycol, butanediol, hexanediol, octanediol, triethylene glycol, and bisphenol A structural units. Ion release profiles were measured as a function of initial ion concentration within the microcapsule, ion type, and microcapsule chemical structure. The rate of ion release increased with initial concentration of ion stored in the microcapsule over a range of 0.5-3.0M. The monomer used in the synthesis of the membrane had a significant effect on ion release rates at 3.0 M salt concentration. At 1.0 M, the ethylene glycol released ions significantly faster than the hexanediol-, octanediol-, and butanediol-based microcapsules. Ion release was fastest for fluoride and slowest for phosphate for the salts used in this study. It was concluded that the microcapsules are capable of releasing calcium, phosphate, and fluoride ions in their biologically available form.

  5. Asymmetric-Structure Analysis of Carbon and Energy Markets

    Science.gov (United States)

    Xu, Wei; Cao, Guangxi

    2016-02-01

    This study aimed to investigate the asymmetric structure between the carbon and energy markets from two aspects of different trends (up or down) and volatility-transmission direction using asymmetric detrended cross-correlation analysis (DCCA) cross-correlation coefficient test, multifractal asymmetric DCCA (MF-ADCCA) method, asymmetric volatility-constrained correlation metric and time rate of information-flow approach. We sampled 1283 observations from January 2008 to December 2012 among pairs of carbon and energy markets for analysis. Empirical results show that the (1) asymmetric characteristic from the cross-correlation between carbon and returns in the energy markets is significant, (2) asymmetric cross-correlation between carbon and energy market price returns is persistent and multifractral and (3) volatility of the base assets of energy market returns is more influential to the base asset of the carbon market than that of the energy market.

  6. Cylindrical Asymmetrical Capacitors for Use in Outer Space

    Science.gov (United States)

    Campbell, Jonathan W.

    2007-01-01

    A report proposes that cylindrical asymmetrical capacitors (CACs) be used to generate small thrusts for precise maneuvering of spacecraft on long missions. The report notes that it has been known for decades that when high voltages are applied to CACs in air, thrusts are generated - most likely as a result of ionization of air molecules and acceleration of the ions by the high electric fields. The report goes on to discuss how to optimize the designs of CACs for operation as thrusters in outer space. Components that could be used to enable outerspace operation include a supply of gas and a shroud, partly surrounding a CAC, into which the gas would flow. Other elements of operation and design discussed in the report include variation of applied voltage and/or of gas flow to vary thrust, effects of CAC and shroud dimensions on thrust and weight, some representative electrode configurations, and several alternative designs, including one in which the basic CAC configuration would be modified into something shaped like a conventional rocket engine with converging/diverging nozzle and an anode with gas feed in the space that, in a conventional rocket engine, would be the combustion chamber.

  7. Aspects of particle production in isospin-asymmetric matter

    Science.gov (United States)

    Ferini, G.; Colonna, M.; Gaitanos, T.; Di Toro, M.

    2005-11-01

    The production/absorption rate of particles in compressed and heated asymmetric matter is studied using a Relativistic Mean Field (RMF) transport model with an isospin-dependent collision term. Just from energy conservation in the elementary production/absorption processes we expect to see a strong dependence of the yields on the basic Lorentz structure of the isovector effective interaction, due to isospin effects on the scalar and vector self-energies of the hadrons. This will be particularly evident for the ratio of the rates of particles produced with different charges: results are shown for π/π, K/K yields. In order to simplify the analysis we perform RMF cascade simulations in a box with periodic boundary conditions. In this way we can better pin down all such fine relativistic effects in particle production, that could likely show up even in realistic heavy ion collisions. In fact, the box properties are tuned in order to reproduce the heated dense matter formed during a nucleus-nucleus collision in the few A GeV beam energy region. In particular, K production is expected to be directly related to the high density behaviour of the symmetry energy, since kaons are produced very early during the high density stage of the collision and their mean free path is rather large. We show that the K/K ratio reflects important isospin contributions on the production rates just because of the large sensitivity around the threshold. The results are very promising for the possibility of a direct link between particle production data in exotic Heavy Ion Collisions (HIC) and the isospin-dependent part of the Equation of State (EoS) at high baryon densities.

  8. Asymmetric Synthesis of Both Enantiomers of Disparlure

    Institute of Scientific and Technical Information of China (English)

    王志刚; 郑剑峰; 黄培强

    2012-01-01

    Starting from propargyl alcohol (12), and on the basis of Zhou's modified Sharpless asymmetric epoxidation, the sex pheromone of the Gypsy moth, disparlure (+)-8 and its enantiomer (-)-8 have been synthesized, each in six steps, with overall yields of 29% for (+)-8 and 27% for (-)-8 (ee〉98%). The use of the sequential coupling tactic renders the method flexible, which is applicable to the synthesis of other cis-epoxy pheromones.

  9. Infinite dimensional mixed economies with asymmetric information

    CERN Document Server

    Bhowmik, Anuj

    2011-01-01

    In this paper, we study asymmetric information economies consisting of both non-negligible and negligible agents and having ordered Banach spaces as their commodity spaces. In answering a question of Herv\\'{e}s-Beloso and Moreno-Garc\\'{i}a, we establish a characterization of Walrasian expectations allocations by the veto power of the grand coalition. It is also shown that when an economy contains only negligible agents a Vind's type theorem on the private core with the exact feasibility can be restored. This solves a problem of Pesce.

  10. Quantum optics of lossy asymmetric beam splitters

    CERN Document Server

    Uppu, Ravitej; Tentrup, Tristan B H; Pinkse, Pepijn W H

    2016-01-01

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2$\\times$2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers.

  11. Asymmetric chemical reactions by polarized quantum beams

    Science.gov (United States)

    Takahashi, Jun-Ichi; Kobayashi, Kensei

    One of the most attractive hypothesis for the origin of homochirality in terrestrial bio-organic compounds (L-amino acid and D-sugar dominant) is nominated as "Cosmic Scenario"; a chiral impulse from asymmetric excitation sources in space triggered asymmetric reactions on the surfaces of such space materials as meteorites or interstellar dusts prior to the existence of terrestrial life. 1) Effective asymmetric excitation sources in space are proposed as polarized quantum beams, such as circularly polarized light and spin polarized electrons. Circularly polarized light is emitted as synchrotron radiation from tightly captured electrons by intense magnetic field around neutron stars. In this case, either left-or right-handed polarized light can be observed depending on the direction of observation. On the other hand, spin polarized electrons is emitted as beta-ray in beta decay from radioactive nuclei or neutron fireballs in supernova explosion. 2) The spin of beta-ray electrons is longitudinally polarized due to parity non-conservation in the weak interaction. The helicity (the the projection of the spin onto the direction of kinetic momentum) of beta-ray electrons is universally negative (left-handed). For the purpose of verifying the asymmetric structure emergence in bio-organic compounds by polarized quantum beams, we are now carrying out laboratory simulations using circularly polarized light from synchrotron radiation facility or spin polarized electron beam from beta-ray radiation source. 3,4) The target samples are solid film or aqueous solution of racemic amino acids. 1) K.Kobayashi, K.Kaneko, J.Takahashi, Y.Takano, in Astrobiology: from simple molecules to primitive life; Ed. V.Basiuk; American Scientific Publisher: Valencia, 2008. 2) G.A.Gusev, T.Saito, V.A.Tsarev, A.V.Uryson, Origins Life Evol. Biosphere. 37, 259 (2007). 3) J.Takahashi, H.Shinojima, M.Seyama, Y.Ueno, T.Kaneko, K.Kobayashi, H.Mita, M.Adachi, M.Hosaka, M.Katoh, Int. J. Mol. Sci. 10, 3044

  12. On asymmetric causal relationships in Petropolitics

    Directory of Open Access Journals (Sweden)

    Balan Feyza

    2016-01-01

    Full Text Available The aim of this paper is to examine whether the First Law of Petropolitics denominated by Friedman in 2006 is valid for OPEC countries. To do this, this paper analyses the relationship between political risk and oil supply by applying the asymmetric panel causality test suggested by Hatemi-J (2011 to these countries for the period 1984-2014. The results show that the First Law of Petropolitics is valid for Angola, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, and the UAE, given that positive oil supply shocks significantly lead to negative political stability shocks, and negative oil supply shocks significantly lead to positive shocks in political stability.

  13. OFFICER AND COMMANDER IN ASYMMETRIC WARFARE OPERATIONS

    Directory of Open Access Journals (Sweden)

    Giuseppe CAFORIO

    2013-01-01

    Full Text Available Starting from the data of a field research conducted among soldiers with asymmetric warfare experiences from nine different countries, the author seeks to identify and shed light on the various problems that officers with command responsibilities had to face during their missions. A picture emerges of feelings and experiences relating to their first impression upon arriving in the theatre, relations with local armed forces, relations with the local population and local authorities, relations with NGOs, relations with other armies, the impact of the rules of engagement (ROEs, training and education, and operational experiences. The paper ends with a discussion of the lessons learned.

  14. The Asymmetric Effects of Investor Sentiment

    DEFF Research Database (Denmark)

    Lutz, Chandler

    2016-01-01

    are asymmetric: During peak-to-trough periods of investor sentiment (sentiment contractions), high sentiment predicts low future returns for the cross section of speculative stocks and for the market overall, whereas the relationship between sentiment and future returns is positive but relatively weak during......We use the returns on lottery-like stocks and a dynamic factor model to construct a novel index of investor sentiment. This new measure is highly correlated with other behavioral indicators, but more closely tracks speculative episodes. Our main new finding is that the effects of sentiment...... trough-to-peak episodes (sentiment expansions). Overall, these results match theories and anecdotal accounts of investor sentiment....

  15. Quantum optics of lossy asymmetric beam splitters

    Science.gov (United States)

    Uppu, Ravitej; Wolterink, Tom A. W.; Tentrup, Tristan B. H.; Pinkse, Pepijn W. H.

    2016-07-01

    We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2$\\times$2 optical circuit. The losses in the circuit result in a non-unitary scattering matrix with a non-trivial set of constraints on the elements of the scattering matrix. Our analysis using the noise operator formalism shows that the loss allows tunability of quantum interference to an extent not possible with a lossless beam splitter. Our theoretical studies support the experimental demonstrations of programmable quantum interference in highly multimodal systems such as opaque scattering media and multimode fibers.

  16. Massless sunset diagrams in finite asymmetric volumes

    Science.gov (United States)

    Niedermayer, F.; Weisz, P.

    2016-06-01

    This paper discusses the methods and the results used in an accompanying paper describing the matching of effective chiral Lagrangians in dimensional and lattice regularizations. We present methods to compute 2-loop massless sunset diagrams in finite asymmetric volumes in the framework of these regularizations. We also consider 1-loop sums in both regularizations, extending the results of Hasenfratz and Leutwyler for the case of dimensional regularization and we introduce a new method to calculate precisely the expansion coefficients of the 1-loop lattice sums.

  17. Plasma current resonance in asymmetric toroidal systems

    Energy Technology Data Exchange (ETDEWEB)

    Hazeltine, R. D. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Catto, Peter J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, 167 Albany Street, Cambridge, Massachusetts 02139 (United States)

    2015-09-15

    The well-known singularity in the magnetic differential equation for plasma current in an asymmetric toroidal confinement system is resolved by including in the pressure tensor corrections stemming from finite Larmor radius. The result provides an estimate of the amplitude of spikes in the parallel current that occur on rational magnetic surfaces. Resolution of the singularity is shown to depend on both the ambipolarity condition—the requirement of zero surface-averaged radial current—and the form of the magnetic differential equation near the rational surface.

  18. Plasmonic photodetectors based on asymmetric nanogap electrodes

    Science.gov (United States)

    Ge, Junyu; Luo, Manlin; Zou, Wanghui; Peng, Wei; Duan, Huigao

    2016-08-01

    Hot electrons excited by plasmon resonance in nanostructure can be employed to enhance the properties of photodetectors, even when the photon energy is lower than the bandgap of the semiconductor. However, current research has seldom considered how to realize the efficient collection of hot electrons, which restricts the responsivity of the device. In this paper, a type of plasmonic photodetector based on asymmetric nanogap electrodes is proposed. Owing to this structure, the device achieves responsivities as high as 0.45 and 0.25 mA/W for wavelengths of 1310 and 1550 nm, respectively. These insights can aid the realization of efficient plasmon-enhanced photodetectors for infrared detection.

  19. Nanotribology of Symmetric and Asymmetric Liquid Lubricants

    Directory of Open Access Journals (Sweden)

    Shinji Yamada

    2010-03-01

    Full Text Available When liquid molecules are confined in a narrow gap between smooth surfaces, their dynamic properties are completely different from those of the bulk. The molecular motions are highly restricted and the system exhibits solid-like responses when sheared slowly. This solidification behavior is very dependent on the molecular geometry (shape of liquids because the solidification is induced by the packing of molecules into ordered structures in confinement. This paper reviews the measurements of confined structures and friction of symmetric and asymmetric liquid lubricants using the surface forces apparatus. The results show subtle and complex friction mechanisms at the molecular scale.

  20. Security-Preserving Asymmetric Protocol Encapsulation

    OpenAIRE

    Vaudenay, Serge; Phan, Raphael C-W

    2007-01-01

    Query-response based protocols between a client and a server such as SSL, TLS, SSH are asymmetric in the sense that the querying client and the responding server play different roles, and for which there is a need for two-way linkability between queries and responses within the protocol. We are motivated by the observation that though results exist in other related contexts, no provably secure scheme has been applied to the setting of client-server protocols, which differ from conventional co...