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Sample records for selective glass electrodes

  1. Ion-selective electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Mikhelson, Konstantin N. [St. Petersburg State Univ. (Russian Federation). Ion-Selective Electrode Laboratory

    2013-06-01

    Ion-selective electrodes (ISEs) have a wide range of applications in clinical, environmental, food and pharmaceutical analysis as well as further uses in chemistry and life sciences. Based on his profound experience as a researcher in ISEs and a course instructor, the author summarizes current knowledge for advanced teaching and training purposes with a particular focus on ionophore-based ISEs. Coverage includes the basics of measuring with ISEs, essential membrane potential theory and a comprehensive overview of the various classes of ion-selective electrodes. The principles of constructing ISEs are outlined, and the transfer of methods into routine analysis is considered.

  2. Ion-selective electrodes

    CERN Document Server

    Mikhelson, Konstantin N

    2013-01-01

    Ion-selective electrodes (ISEs) have a wide range of applications in clinical, environmental, food and pharmaceutical analysis as well as further uses in chemistry and life sciences. Based on his profound experience as a researcher in ISEs and a course instructor, the author summarizes current knowledge for advanced teaching and training purposes with a particular focus on ionophore-based ISEs. Coverage includes the basics of measuring with ISEs, essential membrane potential theory and a comprehensive overview of the various classes of ion-selective electrodes. The principles of constructing I

  3. Ion-selective electrode reviews

    CERN Document Server

    Thomas, J D R

    1985-01-01

    Ion-Selective Electrode Reviews, Volume 7 is a collection of papers that covers the applications of electrochemical sensors, along with the versatility of ion-selective electrodes. The coverage of the text includes solid contact in membrane ion-selective electrodes; immobilized enzyme probes for determining inhibitors; potentiometric titrations based on ion-pair formation; and application of ion-selective electrodes in soil science, kinetics, and kinetic analysis. The text will be of great use to chemists and chemical engineers.

  4. Ion-selective electrode reviews

    CERN Document Server

    Thomas, J D R

    1983-01-01

    Ion-Selective Electrode Reviews, Volume 5 is a collection of articles that covers ion-speciation. The book aims to present the advancements of the range and capabilities of selective ion-sensors. The topics covered in the selection are neutral carrier based ion-selective electrodes; reference electrodes and liquid junction effects in ion-selective electrode potentiometry; ion transfer across water/organic phase boundaries and analytical; and carbon substrate ion-selective electrodes. The text will be of great use to chemists and chemical engineers.

  5. Ion-selective electrode reviews

    CERN Document Server

    Thomas, J D R

    1982-01-01

    Ion-Selective Electrode Reviews, Volume 3, provides a review of articles on ion-selective electrodes (ISEs). The volume begins with an article on methods based on titration procedures for surfactant analysis, which have been developed for discrete batch operation and for continuous AutoAnalyser use. Separate chapters deal with detection limits of ion-selective electrodes; the possibility of using inorganic ion-exchange materials as ion-sensors; and the effect of solvent on potentials of cells with ion-selective electrodes. Also included is a chapter on advances in calibration procedures, the d

  6. Recovery of fluoride ion selective electrode

    International Nuclear Information System (INIS)

    Monteiro, R.P.G.

    1988-01-01

    A recovery procedure of fluoride ion selective electrode based upon the body radiography of inactive electrode and introduction of suitable internal regeneration solution, is developed. The recovered electrode was tested in standard solutions of fluoride ions (10 sup5) to 10 -1M showing as good performance as the new one. The fluor determination by potentiometric measurements with selective electrode is used in nuclear fuel cycle for quality control of thorium and uranium mixed oxide pellets and pellets of uranium dioxides. (author) [pt

  7. Polystyrene Based Silver Selective Electrodes

    Directory of Open Access Journals (Sweden)

    Shiva Agarwal

    2002-06-01

    Full Text Available Silver(I selective sensors have been fabricated from polystyrene matrix membranes containing macrocycle, Me6(14 diene.2HClO4 as ionophore. Best performance was exhibited by the membrane having a composition macrocycle : Polystyrene in the ratio 15:1. This membrane worked well over a wide concentration range 5.0×10-6–1.0×10-1M of Ag+ with a near-Nernstian slope of 53.0 ± 1.0 mV per decade of Ag+ activity. The response time of the sensor is <15 s and the membrane can be used over a period of four months with good reproducibility. The proposed electrode works well in a wide pH range 2.5-9.0 and demonstrates good discriminating power over a number of mono-, di-, and trivalent cations. The sensor has also been used as an indicator electrode in the potentiometric titration of silver(II ions against NaCl solution. The sensor can also be used in non-aqueous medium with no significant change in the value of slope or working concentration range for the estimation of Ag+ in solution having up to 25% (v/v nonaqueous fraction.

  8. Glass Electrode Calibration for Use in the Voltammetric ...

    African Journals Online (AJOL)

    A glass electrode (GE) can be successfully employed to measure pH in the study of metal-ligand equilibria by voltammetry at extremely low pH (between 0 and 2); two consecutive strong acid–strong base titrations involving different base concentrations (recommended to avoid corrosion of the GE in very basic solutions) are ...

  9. Evaluation study of an ion selective field effect transistor electrode for measuring quality parameters of fuel ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Gonzaga, Fabiano B.; Sobral, Sidney P.; Ribeiro, Carla M.; Goncalves, Mary A., E-mail: fbgonzaga@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia(INMETRO), Duque de Caxias, RJ (Brazil). Div. de Metrologia Quimica

    2013-01-15

    An ion selective field effect transistor (ISFET) electrode was evaluated for measuring pH and acid number (AN) of fuel ethanol and compared to two glass electrodes with different reference filling solutions: KCl aqueous solution (glass-KCl electrode)and LiCl ethanolic solution (glass-LiCl electrode). pH was determined at different measurement times and AN was determined using automatic potentiometric titration. For pH, the glass-KCl electrode showed the best precision and stability, with an average repeatability about four times better when compared to the ISFET electrode for the measurement time of 30 s (as indicated in the ASTM D6423 standard). For AN, the glass-KCl and glass-LiCl electrodes showed similar repeatabilities, which were about three times better than that of the ISFET electrode. In addition, the results from a recovery study demonstrated better accuracy of the glass-LiCl electrode, with a recovery value of 100.1% (author)

  10. Chemical sensors in natural water: peculiarities of behaviour of chalcogenide glass electrodes for determination of copper, lead and cadmium ions

    International Nuclear Information System (INIS)

    Seleznev, B.L.; Legin, A.V.; Vlasov, Yu.G.

    1996-01-01

    Specific features of chemical sensors (chalcogenide glass and crystal ion-selective electrodes) behaviour have been studied to determine copper (2), lead, cadmium and fluorine in the course of in situ measurements, including long-term uninterrupted testing, for solving the problem of inspection over natural water contamination. 16 refs., 3 figs., 2 tabs

  11. Contribution to the study of fluoride dosing by using a membrane selective electrode

    International Nuclear Information System (INIS)

    Rivas, Jean de

    1972-01-01

    As the method of dosing fluoride ions by precipitation with lead fluorochloride is not very satisfying, the author reports the study of a new process for the dosing of the fluorine ion by using a selective electrode. After some generalities on selective electrodes (principle, types, operation principle) and some recalls and definitions (Galvani and Volta potential, stability constants of complexes, principles of diffusion in solids), the author reports the study of the diffusion potential in glass membranes, the study of the membrane potential, and the study of the ion exchange equilibrium. He presents methods of calculation of selectivity coefficients of membrane electrodes, and the reports experiments performed in laboratory

  12. Site Selection for Hvdc Ground Electrodes

    Science.gov (United States)

    Freire, P. F.; Pereira, S. Y.

    2014-12-01

    High-Voltage Direct Current (HVDC) transmission systems are composed of a bipole transmission line with a converter substation at each end. Each substation may be equipped with a HVDC ground electrode, which is a wide area (up to 1 km Ø) and deep (from 3 to 100m) electrical grounding. When in normal operation, the ground electrode will dissipate in the soil the unbalance of the bipole (~1.5% of the rated current). When in monopolar operation with ground return, the HVDC electrode will inject in the soil the nominal pole continuous current, of about 2000 to 3000 Amperes, continuously for a period up to a few hours. HVDC ground electrodes site selection is a work based on extensive geophysical and geological surveys, in order to attend the desired design requirements established for the electrodes, considering both its operational conditions (maximum soil temperature, working life, local soil voltage gradients etc.) and the interference effects on the installations located up to 50 km away. This poster presents the geophysical investigations conducted primarily for the electrodes site selection, and subsequently for the development of the crust resistivity model, which will be used for the interference studies. A preliminary site selection is conducted, based on general geographical and geological criteria. Subsequently, the geology of each chosen area is surveyed in detail, by means of electromagnetic/electrical geophysical techniques, such as magnetotelluric (deep), TDEM (near-surface) and electroresistivity (shallow). Other complementary geologic and geotechnical surveys are conducted, such as wells drilling (for geotechnical characterization, measurement of the water table depth and water flow, and electromagnetic profiling), and soil and water sampling (for measurement of thermal parameters and evaluation of electrosmosis risk). The site evaluation is a dynamic process along the surveys, and some sites will be discarded. For the two or three final sites, the

  13. Selective functionalization of patterned glass surfaces

    NARCIS (Netherlands)

    Ploetz, E.; Visser, B.; Slingenbergh, W.; Evers, K.; Martinez-Martinez, D.; Pei, Y. T.; Feringa, B. L.; De Hosson, J. Th. M.; Cordes, T.; van Dorp, W. F.

    2014-01-01

    Tailored writing and specific positioning of molecules on nanostructures is a key step for creating functional materials and nano-optical devices, or interfaces for synthetic machines in various applications. We present a novel approach for the selective functionalization of patterned glass surfaces

  14. Acidity Measurements with the Glass Electrode in H2O-D2O Mixtures

    DEFF Research Database (Denmark)

    Mikkelsen, K.; Nielsen, Sigurd Olaf

    1960-01-01

    Determinations at 22° of the thermodynamic dissociation constant of acetic arid in ordinary water and in deuteriumenriched water (98.0 volume % D20) demonstrate that an ordinary Radiometer glass electrode type G 202A under convenient experimental conditions exhibits the theoretical response...... to variations in the hydrogen-ion concentration in both solvents in the range between 2 x 10 -2 and 2 x 10 -5 M. The acidity determinations involve standardization and storage of the glass electrode in solutions in HzO and subsequent drying of the glass electrode with mercury before immersing it in the 0.5-ml...

  15. REACTION PRODUCTS AND CORROSION OF MOLYBDENUM ELECTRODE IN GLASS MELT CONTAINING ANTIMONY OXIDES AND SODIUM SULFATE

    Directory of Open Access Journals (Sweden)

    JIŘÍ MATĚJ

    2012-09-01

    Full Text Available The products on the interface of a molybdenum electrode and glass melt were investigated primarily at 1400°C in three model glass melts without ingredients, with 1 % Sb2O3 and with 1 % Sb2O3 and 0.5 % SO3 (wt. %, both under and without load by alternating current. Corrosion of the molybdenum electrode in glass melt without AC load is higher by one order of magnitude if antimony oxides are present. The corrosion continues to increase if sulfate is present in addition to antimony oxides. Isolated antimony droplets largely occur on the electrode-glass melt interface, and numerous droplets are also dissipated in the surrounding glass if only antimony oxides are present in the glass melt. A comparatively continuous layer of antimony occurs on the interface if SO3 is also present, antimony being always in contact with molybdenum sulfide. Almost no antimony droplets are dissipated in the glass melt. The total amount of precipitated antimony also increases. The presence of sulfide on the interface likely facilitates antimony precipitation. The reaction of molybdenum with antimony oxides is inhibited in sites covered by an antimony layer. The composition of sulfide layers formed at 1400°C approximates that of Mo2S3. At 1100°C, the sulfide composition approximates that of MoS4. Corrosion multiplies in the glass melt without additions through the effect of AC current, most molybdenum being separated in the form of metallic particles. Corrosion also increases in the glass melt containing antimony oxides. This is due to increased corrosion in the neighborhood of the separated antimony droplets. This mechanism also results in the loosening of molybdenum particles. The amount of precipitated antimony also increases through the effect of the AC current. AC exerts no appreciable effect on either corrosion, the character of the electrode-glass interface, or antimony precipitation in the glass melt containing SO3.

  16. Single electrode electrochemical detection in hybrid poly(dimethylsiloxane)/glass multichannel micro devices

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Ney Henrique; Almeida, Andre Luis de Jesus de; Piazzeta, Maria Helena de Oliveira; Gobbia, Angelo Luiz [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil). Lab. de Microfabricacao; Jesus, Dosil Pereira de [Instituto Nacional de Ciencia e Tecnologia em Bioanalitica (INCTBio), Campinas, SP (Brazil); Deblire, Ariane; Silva, Jose Alberto Fracassi da [Universidade Estadual de Campinas (IQ/UNICAMP), SP (Brazil). Inst. de Quimica

    2009-07-01

    The fabrication process of a novel multichannel {mu}TAS based on PDMS and glass materials and with fully-integrated electrodes for amperometric detection has been described. Using the facilities of the Microfabrication Lab. (LMF) at Brazilian Synchrotron Light Laboratory (LNLS), soft-lithography, lift-off and O{sub 2} plasma surface activation sealing techniques were employed for rapid proto typing of cost effective PDMS/glass microchips. Fast calibration procedures were possible for the electro oxidation of hydroquinone, thiocyanate, and acetaminophen using Au and Cu electrodes. (author)

  17. Performance of glass RPC with industrial silk-screen-printed electrodes

    International Nuclear Information System (INIS)

    Ambrosio, M.; Candela, A.; De Deo, M.; D'Incecco, M.; Gamba, D.; Giuliano, A.; Gustavino, C.; Morganti, S.; Redaelli, N.; Tonazzo, A.; Trinchero, G.C.

    2003-01-01

    In this paper we describe the performance of several Glass RPCs, where the water-based graphite coating is replaced by a synthetic coating applied using the screen printing technique. As expected, the performance of the detectors is good and reproducible due to the accurate control of the coating resistivity value. The resistance of the coating to the action of mechanical and chemical agents permits an easy electrode cleaning and mounting with respect to the RPC coated with the graphite varnish. This coating, together with the use of float glass as electrode material, allows an industrial production, where the detector characteristics can be tailored as a function of the experiment requirements

  18. Reaction products and corrosion of molybdenum electrode in glass melt containing antimony oxides and sodium sulfate

    Czech Academy of Sciences Publication Activity Database

    Matěj, J.; Langrová, Anna

    2012-01-01

    Roč. 56, č. 3 (2012), s. 280-285 ISSN 0862-5468 Institutional support: RVO:67985831 Keywords : antimony oxides * corrosion * glass melt * Molybdenum electrode * sulfate Subject RIV: DD - Geochemistry Impact factor: 0.418, year: 2012 http://www.ceramics-silikaty.cz/2012/pdf/2012_03_280.pdf

  19. Ambulatory oesophageal pH monitoring: a comparison between antimony, ISFET, and glass pH electrodes

    NARCIS (Netherlands)

    Hemmink, Gerrit J. M.; Weusten, Bas L. A. M.; Oors, Jac; Bredenoord, Albert J.; Timmer, Robin; Smout, André J. P. M.

    2010-01-01

    BACKGROUND AND AIM: Ambulatory oesophageal pH-impedance monitoring is a widely used test to evaluate patients with reflux symptoms. Several types of pH electrodes are available: antimony, ion sensitive field effect transistor (ISFET), and glass electrodes. These pH electrodes have not been compared

  20. Graphene nanoflakes on transparent glass electrode sensor for electrochemical sensing of anti-diabetic drug.

    Science.gov (United States)

    Narang, Jagriti; Malhotra, Nitesh; Singhal, Chaitali; Bhatia, Rishabh; Kathuria, Vikas; Jain, Manan

    2017-04-01

    Metformin (Mf) plays a major role in controlling insulin level of individuals at risk of developing diabetes mellitus. Overdose of Mf can cause lactic acidosis, diarrhoea, cough, or hoarseness, etc. These particulars point out the identification for selective and sensitive methods of Mf determination. In the present work, graphene nanoflakes-polymethylene blue (GNF-PMB) nano-composites were developed onto fluorine-doped tin oxide (SnO 2 /F) coated glass substrates for electrochemical sensing of Mf using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The developed sensor shows quick response time (10 s), linearity as 10-10 3  µM, LOD (0.1 nM), and good shelf life (10 weeks). Attempts have been made to utilize this electrode for estimation of Mf in urine samples. Configured as a highly responsive, reproducible Mf sensor, it combines the electrical properties of GNF and stable electron transfer of PMB. The newly developed Mf sensor presents a promising candidate in point-of-care diagnosis.

  1. A study of the anomalous behaviour of the glass electrode in solutions containing hydrofluoric acid

    DEFF Research Database (Denmark)

    Sørensen, Emil; Lundgaard, T.

    1965-01-01

    A defined surface hydration of the glass electrode is secured by pre-treatment with 0.1 N HF followed by rinsing with pure 0.1 N HCl for a few minutes. On subsequent contact with 0.1 N HCl containing HF, the electrode potential shows a change which is determined by the [HF]. The immediate reaction...... is an adsorption of HF by the glass surface. This is followed, at [HF] higher than 0.01 N, by the substitution of two F− for OH− per Si atom. With increasing HF the attack on the Si-O-Si bonds becomes severe, but it can be tolerated to a considerable degree because the newly formed surface is identical...

  2. Nanomolar determination of Pb (II ions by selective templated electrode

    Directory of Open Access Journals (Sweden)

    Mazloum-Ardakani Mohammad

    2012-01-01

    Full Text Available Polypyrrole modified electrode, prepared by electropolymerization of pyrrole in the presence of methyl red as a dopant, was templated with respect to Pb2+ ion and applied for potentiometric and voltammetric detection of this ion. The templating process improved the analytical response characteristics of the electrode, specially their selectivity, with respect to Pb2+ ion. The improvement depends on both the incorporated ligand (dopant and the templating process, with the latter being more vital. The potentiometric response of the electrode was linear within the Pb2+ concentration range of 2.0×10-6 to 5.0×10-2 M with a near-Nernstian slope of 28.6 mV decade-1 and a detection limit of 7.0 ×10-7 M. The electrode was also used for preconcentration differential pulse anodic stripping voltammetry (DPASV and results showed that peak currents for the incorporated lead species were dependent on the metal ion concentration in the range of 1.0×10-8 to 1.0×10-3 M. The detection limit of DPASV method was 3.5 ×10-9 M. The selectivity of the electrode with respect to some transition metal ions was investigated. The modified-templated electrode was used for the successful assay of lead in two standard reference material samples.

  3. All-solid-state carbonate-selective electrode based on screen-printed carbon paste electrode

    International Nuclear Information System (INIS)

    Li, Guang; Lyu, Xiaofeng; Wang, Zhan; Rong, Yuanzhen; Hu, Ruifen; Wang, You; Luo, Zhiyuan

    2017-01-01

    A novel disposable all-solid-state carbonate-selective electrode based on a screen-printed carbon paste electrode using poly(3-octylthiophene-2,5-diyl) (POT) as an ion-to-electron transducer has been developed. The POT was dropped onto the reaction area of the carbon paste electrode covered by the poly(vinyl chloride) (PVC) membrane, which contains N,N-Dioctyl-3 α ,12 α -bis(4-trifluoroacetylbenzoyloxy)-5 β -cholan-24-amide as a carbonate ionophore. The electrode showed a near-Nernstian slope of  −27.5 mV/decade with a detection limit of 3.6 * 10 −5 mol l −1 . Generally, the detection time was 30 s. Because these electrodes are fast, convenient and low in cost, they have the potential to be mass produced and used in on-site testing as disposable sensors. Furthermore, the repeatability, reproducibility and stability have been studied to evaluate the properties of the electrodes. Measurement of the carbonate was also conducted in a human blood solution and achieved good performance. (paper)

  4. Determination of zirconium by fluoride ion selective electrode

    International Nuclear Information System (INIS)

    Mahanty, B.N.; Sonar, V.R.; Gaikwad, R.; Raul, S.; Das, D.K.; Prakash, A.; Afzal, Md.; Panakkal, J.P.

    2010-01-01

    Full text: Zirconium is used in a wide range of applications including nuclear clad, catalytic converters, surgical appliances, metallurgical furnaces, superconductors, ceramics, lamp filaments, anti corrosive alloys and photographical purposes. Irradiation testing of U-Zr and U-Pu-Zr fuel pins has also demonstrated their feasibility as fuel in liquid metal reactors. Different methods that are employed for the determination of zirconium are spectrophotometry, potentiometry, neutron activation analysis and mass spectrometry. Ion-selective electrode (ISE), selective to zirconium ion has been studied for the direct potentiometric measurements of zirconium ions in various samples. In the present work, an indirect method has been employed for the determination of zirconium in zirconium nitrate sample using fluoride ion selective electrode. This method is based on the addition of known excess amount of fluoride ion to react with the zirconium ion to produce zirconium tetra fluoride at about pH 2-3, followed by determination of residual fluoride ion selective electrode. The residual fluoride ion concentrations were determined from the electrode potential data using calibration plot. Subsequently, zirconium ion concentrations were determined from the concentration of consumed fluoride ions. A precision of about 2% (RSD) with the mean recovery of more than 94% has been achieved for the determination of zirconium at the concentration of 4.40 X 10 -3 moles lit -1

  5. Study of the effect of water vapor on a resistive plate chamber with glass electrodes

    CERN Document Server

    Sakai, H H; Teramoto, Y; Nakano, E E; Takahashi, T T

    2002-01-01

    We studied the effects of water vapor on the efficiencies of resistive plate chambers with glass electrodes, operated in the streamer mode. With moisture in the chamber gas that has freon as a component (water vapor approx 1000 ppm), a decrease in the efficiency (approx 20%) has been observed after operating for a period of several weeks to a few months. From our study, the cause of the efficiency decrease was identified as a change on the cathode surface. In addition, a recovery method was found: flushing for 1 day with argon bubbled through water containing >=3% ammonia, followed by a few weeks of training with dry gas.

  6. Analysis of Various Frequency Selective Shielding Glass by FDTD method

    OpenAIRE

    笠嶋, 善憲; Kasashima, Yoshinori

    2012-01-01

    A frequency Selective shielding (FSS) glass is a print of many same size antennas on a sheet of glass, and it has high shielding properties for one specific frequency. This time, the author analyzed characteristics of various FSSs whose antenna types are different by FDTD method. The antenna types are cross dipole, circular loop, square loop, circular patch, and square patch. As the result, the FSSs can be composed of the various types of the antennas, and the FSSs have broad-band shielding c...

  7. Characterization of 3 mm glass electrodes and development of RPC detectors for INO-ICAL experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Daljeet; Kumar, Ashok; Gaur, Ankit; Kumar, Purnendu; Hasbuddin, Md.; Mishra, Swati; Kumar, Praveen; Naimuddin, Md., E-mail: nayeem@cern.ch

    2015-02-21

    India-based Neutrino Observatory (INO) is a multi-institutional facility, planned to be built up in South India. The INO facility will host a 51 kton magnetized Iron CALorimeter (ICAL) detector to study atmospheric muon neutrinos. Iron plates have been chosen as the target material whereas Resistive Plate Chambers (RPCs) have been chosen as the active detector element for the ICAL experiment. Due to the large number of RPCs needed (∼28,000 of 2 m×2 m in size) for ICAL experiment and for the long lifetime of the experiment, it is necessary to perform a detailed R and D such that each and every parameter of the detector performance can be optimized to improve the physics output. In this paper, we report on the detailed material and electrical properties studies for various types of glass electrodes available locally. We also report on the performance studies carried out on the RPCs made with these electrodes as well as the effect of gas composition and environmental temperature on the detector performance. We also lay emphasis on the usage of materials for RPC electrodes and the suitable environmental conditions applicable for operating the RPC detector for optimal physics output at INO-ICAL experiment.

  8. Selection of Optical Glasses Using Buchdahl's Chromatic Coordinate

    Science.gov (United States)

    Griffin, DeVon W.

    1999-01-01

    This investigation attempted to extend the method of reducing the size of glass catalogs to a global glass selection technique with the hope of guiding glass catalog offerings. Buchdahl's development of optical aberration coefficients included a transformation of the variable in the dispersion equation from wavelength to a chromatic coordinate omega defined as omega = (lambda - lambda(sub 0))/ 1 + 2.5(lambda - lambda(sub 0)) where lambda is the wavelength at which the wavelength is calculated and lambda(sub 0) is a base wavelength about which the expansion is performed. The advantage of this approach is that the dispersion equation may be written in terms of a simple power series and permits direct calculation of dispersion coefficients. While several promising examples were given, a systematic application of the technique to an entire glass catalog and analysis of the subsequent predictions was not performed. The goal of this work was to apply the technique in a systematic fashion to glasses in the Schoft catalog and assess the quality of the predictions.

  9. Analysis of dispersed frequency response for ionic glasses: influence of electrode and nearly constant loss effects

    International Nuclear Information System (INIS)

    Macdonald, J Ross

    2005-01-01

    Analysis by D L Sidebottom of the dispersive frequency response of the real-part of the conductivity, σ'(ω), for many alkali phosphate and metaphosphate glasses, using a fitting model involving a 'universal dynamic response' power law with an exponent n and a constant-loss term, led to anomalous n behaviour that he explained as arising from variable constriction of the local cation conduction space. In order to obtain adequate fits, he eliminated from the data all low-frequency decreases of σ'(ω) below the dc plateau, ones actually associated with electrode effects. Such a cut-off does not, however, eliminate electrode effects possibly present in the high-frequency part of the data range. The results of the present detailed analysis and fitting of both synthetic data and several of his experimental data sets show unequivocally that his anomalous n behaviour arose from neglecting electrode effects. Their inclusion, with or without data cut-off in the fitting model, leads to the expected high-frequency slope value of n = 2/3 associated with bulk conduction, as required by recently published topological effective-dimension considerations for dielectric relaxation in conductive systems. Further, the effects of the inclusion in a full fitting model of series and possibly parallel complex constant-phase-element contributions, representing electrode and nearly constant loss effects, respectively, have been investigated in detail. Such composite models usually lead to best fitting of either the full or cut-off complex data when they include the semi-universal, topologically based K1 bulk model, one indirectly derived from the assumption of stretched-exponential temporal behaviour

  10. A selective iodide ion sensor electrode based on functionalized ZnO nanotubes.

    Science.gov (United States)

    Ibupoto, Zafar Hussain; Khun, Kimleang; Willander, Magnus

    2013-02-04

    In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF) was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10-6 to 1 × 10-1 M) and excellent sensitivity of -62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10-7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

  11. A Selective Iodide Ion Sensor Electrode Based on Functionalized ZnO Nanotubes

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2013-02-01

    Full Text Available In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10−6 to 1 × 10−1 M and excellent sensitivity of –62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10−7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

  12. Selective observation of charge storing ions in supercapacitor electrode materials.

    Science.gov (United States)

    Forse, Alexander C; Griffin, John M; Grey, Clare P

    2018-02-01

    Nuclear magnetic resonance (NMR) spectroscopy has emerged as a useful technique for probing the structure and dynamics of the electrode-electrolyte interface in supercapacitors, as ions inside the pores of the carbon electrodes can be studied separately from bulk electrolyte. However, in some cases spectral resolution can limit the information that can be obtained. In this study we address this issue by showing how cross polarisation (CP) NMR experiments can be used to selectively observe the in-pore ions in supercapacitor electrode materials. We do this by transferring magnetisation from 13 C nuclei in porous carbons to nearby nuclei in the cations ( 1 H) or anions ( 19 F) of an ionic liquid. Two-dimensional NMR experiments and CP kinetics measurements confirm that in-pore ions are located within Ångströms of sp 2 -hybridised carbon surfaces. Multinuclear NMR experiments hold promise for future NMR studies of supercapacitor systems where spectral resolution is limited. Copyright © 2017 University of Cambridge. Published by Elsevier Inc. All rights reserved.

  13. Glass and antimony electrodes for long-term pH monitoring: a dynamic in vitro comparison

    NARCIS (Netherlands)

    Geus, W. P.; Smout, A. J.; Kooiman, J. C.; Lamers, C. B.; Gues, J. W.

    1995-01-01

    OBJECTIVE: To compare the performance of combined glass microelectrodes with monocrystalline and polycrystalline antimony electrodes with external reference in a 24-h dynamic in vitro study. DESIGN AND METHODS: In an artificial stomach, the pH of the contents titrated from pH1-7 and back by NaOH and

  14. OXYGEN BUBBLE DEVELOPMENT ON A PLATINUM ELECTRODE IN BOROSILICATE GLASS MELT BY THE EFFECT OF ALTERNATING CURRENT

    Directory of Open Access Journals (Sweden)

    Jiri Matej

    2014-10-01

    or on alternating reduction and re-forming of oxidic layer on the electrode in the transition range, has been suggested. Start of bubble evolution at low alternating current density has also been observed in simple sodium-calcium-silicate glass melt. A relation between bubble release and platinum corrosion caused by reduced silicon has been suggested

  15. Schiff Base modified on CPE electrode and PCB gold electrode for selective determination of silver ion

    Science.gov (United States)

    Leepheng, Piyawan; Suramitr, Songwut; Phromyothin, Darinee

    2017-09-01

    The schiff base was synthesized by 2,5-thiophenedicarboxaldehyde and 1,2,4-thiadiazole-3,5-diamine with condensation method. There was modified on carbon paste electrode (CPE) and Printed circuit board (PCB) gold electrode for determination silver ion. The schiff base modified electrodes was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The electrochemical study was reported by cyclic voltammetry method and impedance spectroscopy using modified electrode as working electrode, platinum wire and Ag/AgCl as counter electrode and reference electrode, respectively. The modified electrodes have suitable detection for Ag+. The determination of silver ions using the modified electrodes depended linearly on Ag+ concentration in the range 1×10-10 M to 1×10-7 M, with cyclic voltammetry sensitivity were 2.51×108 μAM-1 and 1.88×108 μAM-1 for PCB gold electrode and CPE electrode, respectively, limits of detection were 5.33×10-9 M and 1.99×10-8 M for PCB gold electrode and CPE electrode, respectively. The modified electrodes have high accuracy, inexpensive and can applied to detection Ag+ in real samples.

  16. A copper ion-selective electrode with high selectivity prepared by sol-gel and coated wire techniques.

    Science.gov (United States)

    Mazloum Ardakani, M; Salavati-Niasari, M; Khayat Kashani, M; Ghoreishi, S M

    2004-03-01

    A sol-gel electrode and a coated wire ion-selective poly(vinyl chloride) membrane, based on thiosemicarbazone as a neutral carrier, were successfully developed for the detection of Cu (II) in aqueous solutions. The sol-gel electrode and coated electrode exhibited linear response with Nernstian slopes of 29.2 and 28.1 mV per decade respectively, within the copper ion concentration ranges 1.0 x 10(-5) - 1.0 x 10(-1) M and 6.0 x 10(-6) - 1.0 x 10(-1) M for coated and sol-gel sensors. The coated and sol-gel electrodes show detection limits of 3.0 x 10(-6) and 6.0 x 10(-6) M respectively. The electrodes exhibited good selectivities for a number of alkali, alkaline earth, transition and heavy metal ions. The proposed electrodes have response times ranging from 10-50 s to achieve a 95% steady potential for Cu2+ concentration. The electrodes are suitable for use in aqueous solutions over a wide pH range (4-7.5). Applications of these electrodes for the determination of copper in real samples, and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA, are reported. The lifetimes of the electrodes were tested over a period of six months to investigate their stability. No significant change in the performance of the sol-gel electrode was observed over this period, but after two months the coated wire copper-selective electrode exhibited a gradual decrease in the slope. The selectivity of the sol-gel electrode was found to be better than that of the coated wire copper-selective electrode. Based on these results, a novel sol-gel copper-selective electrode is proposed for the determination of copper, and applied to real sample assays.

  17. Measurement of ac electrical conductivity of molten glass by impedance measurement using co-axial cylinder electrode

    International Nuclear Information System (INIS)

    Shah, J.G.; Yalmali, V.S.; Tawde, Manisha; Mishra, R.

    2006-01-01

    The need of nuclear power as an energy source requires the solution of many problems. One of the most important is fixation of high level radioactive waste (HLW) in suitable borosilicate glass formulation. The major issue with this process is maximum waste loading in the final vitrified product without compromising on long term product characteristics. The electrical resistivity measurement at high temperature could not be measured with good precision using standard parallel plate electrode configuration due to error in cell constant measurement. Hence a high accuracy, calibration free technique consisting of co-axial electrodes was employed

  18. Survey of glass plutonium contents and poison selection

    Energy Technology Data Exchange (ETDEWEB)

    Plodinec, M.J.; Ramsey, W.G. [Westinghouse Savannah River Company, Aiken, SC (United States); Ellison, A.J.G.; Shaw, H. [Lawrence Livermore National Laboratory, CA (United States)

    1996-05-01

    If plutonium and other actinides are to be immobilized in glass, then achieving high concentrations in the glass is desirable. This will lead to reduced costs and more rapid immobilization. However, glasses with high actinide concentrations also bring with them undersirable characteristics, especially a greater concern about nuclear criticality, particularly in a geologic repository. The key to achieving a high concentration of actinide elements in a glass is to formulate the glass so that the solubility of actinides is high. At the same time, the glass must be formulated so that the glass also contains neutron poisons, which will prevent criticality during processing and in a geologic repository. In this paper, the solubility of actinides, particularly plutonium, in three types of glasses are discussed. Plutonium solubilities are in the 2-4 wt% range for borosilicate high-level waste (HLW) glasses of the type which will be produced in the US. This type of glass is generally melted at relatively low temperatures, ca. 1150{degrees}C. For this melting temperature, the glass can be reformulated to achieve plutonium solubilities of at least 7 wt%. This low melting temperature is desirable if one must retain volatile cesium-137 in the glass. If one is not concerned about cesium volatility, then glasses can be formulated which can contain much larger amounts of plutonium and other actinides. Plutonium concentrations of at least 15 wt% have been achieved. Thus, there is confidence that high ({ge}5 wt%) concentrations of actinides can be achieved under a variety of conditions.

  19. TXRF study of electrochemical deposition of metals on glass-ceramic carbon electrode surfaces

    International Nuclear Information System (INIS)

    Alov, N.; Oskolok, K.; Wittershagen, A.; Mertens, M.; Rittmeyer, C.; Kolbesen, B.O.

    2000-01-01

    Nowadays the methods of solid surface analysis are widely used to study the thermodynamic and kinetic aspects of joint electrochemical deposition of metals on solid substrates. In this work the surfaces of some binary and ternary metal electrodeposits on disc glass-ceramic carbon electrodes were studied by total-reflection x-ray fluorescence spectroscopy (TXRF). Metal alloys were obtained as a result of electrochemical co-deposition of copper, cadmium and lead from n x 10 -4 M (Cu, Cd, Pb)(NO 3 ) 2 + 0.01 M HNO 3 solutions under mixing. TXRF measurements were performed with an ATOMIKA EXTRA II A spectrometer using Mo K α and W (Brems) primary excitation. The serious advantage of TXRF as a method of near-surface analysis is very high element sensitivity. Apart from main elements (Cu, Cd, Pb) we have detected trace elements (Cl, Ag, Pt, Hg) which are present in working solution and has an effect to the electrodeposit formation. The comparison of TXRF data with information obtained by X-ray photoelectron spectroscopy and electron-probe x-ray microanalysis permits to realize depth profiling electrochemical alloys. In particular it was found that in binary systems Cu-Pb and Cu-Cd the relative lead and cadmium content on the electrodeposit surface is considerably greater than in the bulk. These phenomena are due to the features of metal nucleation and growth mechanisms. High sensitivity of TXRF to surface morphology and the correlation of TXRF and scanning electron microscopy data allow to determine the area of prevailing location of metal in the heterogeneous alloy surface. So we have established that in Cu-Pb and Cu-Cd-Pb systems solid solution of copper and lead is formed: significant part of lead is deposited not only in specific 3D-clusters but also in copper thin film. It was demonstrated that the near-surface TXRF analysis of metal electrodeposits on solid electrodes is highly effective to study the mechanisms of metal nucleation, metal cluster and thin film

  20. Simulation of multipolar fiber selective neural stimulation using intrafascicular electrodes

    NARCIS (Netherlands)

    Meier, J.H.; Meier, Jan H.; Rutten, Wim; Zoutman, Arne E.; Boom, H.B.K.; Bergveld, Piet

    1992-01-01

    A realistic, quantitative model for the excitation of myelinated nerve fibers by intrafascicular electrodes is presented. It predicts the stimulatory regions of any configuration of any number of electrodes, positioned anywhere inside the fascicle. The model has two parts. First, the nerve fiber is

  1. STRESS RELAXATION CHARACTERISTICS OF SELECTED COMMERCIALLY PRODUCED GLASSES

    Directory of Open Access Journals (Sweden)

    Chocholoušek J.

    2013-06-01

    Full Text Available This paper describes a quantitative method of stress relaxation measurement in prismatic glass samples during two different time-temperature regimes using the Sénarmont compensator. Four types of glass (Barium crystal glass, Eutal, Simax, and Container glass were subjected to observation in an assembled measuring device. Results will be used for parameterization of the Tool-Narayanaswamy-Mazurin model and consequently implemented in a finite element method code.

  2. Generalized Selectivity Description for Polymeric Ion-Selective Electrodes Based on the Phase Boundary Potential Model.

    Science.gov (United States)

    Bakker, Eric

    2010-02-15

    A generalized description of the response behavior of potentiometric polymer membrane ion-selective electrodes is presented on the basis of ion-exchange equilibrium considerations at the sample-membrane interface. This paper includes and extends on previously reported theoretical advances in a more compact yet more comprehensive form. Specifically, the phase boundary potential model is used to derive the origin of the Nernstian response behavior in a single expression, which is valid for a membrane containing any charge type and complex stoichiometry of ionophore and ion-exchanger. This forms the basis for a generalized expression of the selectivity coefficient, which may be used for the selectivity optimization of ion-selective membranes containing electrically charged and neutral ionophores of any desired stoichiometry. It is shown to reduce to expressions published previously for specialized cases, and may be effectively applied to problems relevant in modern potentiometry. The treatment is extended to mixed ion solutions, offering a comprehensive yet formally compact derivation of the response behavior of ion-selective electrodes to a mixture of ions of any desired charge. It is compared to predictions by the less accurate Nicolsky-Eisenman equation. The influence of ion fluxes or any form of electrochemical excitation is not considered here, but may be readily incorporated if an ion-exchange equilibrium at the interface may be assumed in these cases.

  3. Women's participation in parliament: 'Glass ceiling' syndrome and party selection

    Directory of Open Access Journals (Sweden)

    Čičkarić Lilijana

    2014-01-01

    Full Text Available The impact of 'glass ceiling' syndrome and party selection on participation of women in parliament and other political institutions are examined in this article. 'Glass ceiling' syndrome, which means invisible, but almost impenetrable border that women face in professional life, keeping them away from positions of influence and progress in career, is the main reason for the small number of women involved in politics. According to the focus of the research, there are three groups of barriers to women's political participation. Most researchers examine the influence of the political system, institutional and legal mechanisms, the question of their transparency and functional improvement. Significantly less frequent approach came from authors who are concentrated on the social and economic barriers, financial conditions and the broader social context. The third group consists of those who are considering the ideological and psychological barriers, patriarchal cultural patterns, traditional gender roles, self-confidence, ambition and women's desire to be involved in politics. Political parties are key actors in the process of discrimination against women, because they do not allow them to be selected in a number of political functions. There are many factors that determine that the issue of gender equality is variously interpreted in political parties. The most present are contextual and ideological factors, referring to a different definition of the status of women on the political agenda, the social climate in terms of gender equality and respect for human rights, the level of social development and political freedom. Then come organizational factors pertaining to the structure of parties, the manner in which the leadership is elected, whether there are internal women's pressure groups and lobbying, and are women leaders are visible on high positions in decision-making process. Finally, there are institutional-legal factors, which include the type

  4. Rapid determination of trace level copper in tea infusion samples by solid contact ion selective electrode

    Directory of Open Access Journals (Sweden)

    Aysenur Birinci

    2016-07-01

    Full Text Available A new solid contact copper selective electrode with a poly (vinyl chloride (PVC membrane consisting of o-xylylenebis(N,N-diisobutyldithiocarbamate as ionophore has been prepared. The main novelties of constructed ion selective electrode concept are the enhanced robustness, cheapness, and fastness due to the use of solid contacts. The electrode exhibits a rapid (< 10 seconds and near-Nernstian response to Cu2+ activity from 10−1 to 10−6 mol/L at the pH range of 4.0–6.0. No serious interference from common ions was found. The electrode characterizes by high potential stability, reproducibility, and full repeatability. The electrode was used as an indicator electrode in potentiometric titration of Cu(II ions with EDTA and for the direct assay of tea infusion samples by means of the calibration graph technique. The results compared favorably with those obtained by the atomic absorption spectroscopy (AAS.

  5. Design and in vivo evaluation of more efficient and selective deep brain stimulation electrodes

    Science.gov (United States)

    Howell, Bryan; Huynh, Brian; Grill, Warren M.

    2015-08-01

    Objective. Deep brain stimulation (DBS) is an effective treatment for movement disorders and a promising therapy for treating epilepsy and psychiatric disorders. Despite its clinical success, the efficiency and selectivity of DBS can be improved. Our objective was to design electrode geometries that increased the efficiency and selectivity of DBS. Approach. We coupled computational models of electrodes in brain tissue with cable models of axons of passage (AOPs), terminating axons (TAs), and local neurons (LNs); we used engineering optimization to design electrodes for stimulating these neural elements; and the model predictions were tested in vivo. Main results. Compared with the standard electrode used in the Medtronic Model 3387 and 3389 arrays, model-optimized electrodes consumed 45-84% less power. Similar gains in selectivity were evident with the optimized electrodes: 50% of parallel AOPs could be activated while reducing activation of perpendicular AOPs from 44 to 48% with the standard electrode to 0-14% with bipolar designs; 50% of perpendicular AOPs could be activated while reducing activation of parallel AOPs from 53 to 55% with the standard electrode to 1-5% with an array of cathodes; and, 50% of TAs could be activated while reducing activation of AOPs from 43 to 100% with the standard electrode to 2-15% with a distal anode. In vivo, both the geometry and polarity of the electrode had a profound impact on the efficiency and selectivity of stimulation. Significance. Model-based design is a powerful tool that can be used to improve the efficiency and selectivity of DBS electrodes.

  6. All-solid-state potassium-selective electrode using graphene as the solid contact

    DEFF Research Database (Denmark)

    Li, Fenghua; Ye, Junjin; Zhou, Min

    2012-01-01

    Graphene sheets are used for the first time to fabricate a new type of solid-contact ion-selective electrode (SC-ISE) as the intermediate layer between an ionophore-doped solvent polymeric membrane and a glassy carbon electrode. The new transducing layer was characterized by transmission electron...

  7. Time-dependent ion selectivity in capacitive charging of porous electrodes

    NARCIS (Netherlands)

    Zhao, R.; Soestbergen, M.; Rijnaarts, H.H.M.; Wal, van der A.F.; Bazant, M.Z.; Biesheuvel, P.M.

    2012-01-01

    In a combined experimental and theoretical study, we show that capacitive charging of porous electrodes in multicomponent electrolytes may lead to the phenomenon of time-dependent ion selectivity of the electrical double layers (EDLs) in the electrodes. This effect is found in experiments on

  8. Ion-selective electrodes in organic elemental and functional group analysis: a review

    International Nuclear Information System (INIS)

    Selig, W.

    1977-01-01

    The literature on the use of ion-selective electrodes in organic elemental and functional group analysis is surveyed in some detail. The survey is complete through Chemical Abstracts, Vol. 83 (1975). 40 figures, 52 tables, 236 references

  9. Ion-selective electrodes in organic elemental and functional group analysis: a review

    Energy Technology Data Exchange (ETDEWEB)

    Selig, W.

    1977-11-08

    The literature on the use of ion-selective electrodes in organic elemental and functional group analysis is surveyed in some detail. The survey is complete through Chemical Abstracts, Vol. 83 (1975). 40 figures, 52 tables, 236 references.

  10. Ion-selective solid-phase electrode sensitive to ammonium ions

    International Nuclear Information System (INIS)

    Vlasov, Yu.G.; Milonova, M.S.; Antonov, P.P.; Bychkov, E.A.; Ehfa, A.Ya.

    1983-01-01

    Ammonium phosphomolybdate is investigated for the purpose of using it as membrane material of ammonium-selective solid-phase electrodes. Estimation of proton mobility and ion conductivity of ammonium phosphomolybdate is performed

  11. Glass and Glass-Ceramic Materials from Simulated Composition of Lunar and Martian Soils: Selected Properties and Potential Applications

    Science.gov (United States)

    Ray, C. S.; Sen, S.; Reis, S. T.; Kim, C. W.

    2005-01-01

    In-situ resource processing and utilization on planetary bodies is an important and integral part of NASA's space exploration program. Within this scope and context, our general effort is primarily aimed at developing glass and glass-ceramic type materials using lunar and martian soils, and exploring various applications of these materials for planetary surface operations. Our preliminary work to date have demonstrated that glasses can be successfully prepared from melts of the simulated composition of both lunar and martian soils, and the melts have a viscosity-temperature window appropriate for drawing continuous glass fibers. The glasses are shown to have the potential for immobilizing certain types of nuclear wastes without deteriorating their chemical durability and thermal stability. This has a direct impact on successfully and economically disposing nuclear waste generated from a nuclear power plant on a planetary surface. In addition, these materials display characteristics that can be manipulated using appropriate processing protocols to develop glassy or glass-ceramic magnets. Also discussed in this presentation are other potential applications along with a few selected thermal, chemical, and structural properties as evaluated up to this time for these materials.

  12. Quaternary alkylammonium and alkylphosphonium pertechnetates. Application to pertechnetate ion-selective electrodes

    International Nuclear Information System (INIS)

    German, K.E.; Dorokhov, A.V.; Tarasov, A.V.; Baulin, V.E.; Peretroukhine, V.; Tsivadze, A.Yu.; Kopytin, A.V.; Politov, Yu.; Pyatova, E.N.

    2005-01-01

    Pertechnetate ion-selective PVC membrane electrodes based on quaternary alkylammonium and phosphonium salts (bromides and pertechnetates) were examined. The most favorable ionophore was tetradecyltrimethylammonium bromide. The response function was linear within the concentration range 10 -2 -10 -6 mol/L and the slope was 52 mV/pTcO 4 . The detection limit remained at 5x10 -7 mol/L. The selectivity and response time of the electrodes was studied and it was found that the electrodes exhibited high selectivity to TcO 4 - -anion against the main inorganic components of radioactive waste solutions and environmental waters (nitrate, sulfate, chloride and others). The electrodes response was stable over a wide pH range. (author)

  13. Selecting electrode configurations for image-guided cochlear implant programming using template matching.

    Science.gov (United States)

    Zhang, Dongqing; Zhao, Yiyuan; Noble, Jack H; Dawant, Benoit M

    2018-04-01

    Cochlear implants (CIs) are neural prostheses that restore hearing using an electrode array implanted in the cochlea. After implantation, the CI processor is programmed by an audiologist. One factor that negatively impacts outcomes and can be addressed by programming is cross-electrode neural stimulation overlap (NSO). We have proposed a system to assist the audiologist in programming the CI that we call image-guided CI programming (IGCIP). IGCIP permits using CT images to detect NSO and recommend deactivation of a subset of electrodes to avoid NSO. We have shown that IGCIP significantly improves hearing outcomes. Most of the IGCIP steps are robustly automated but electrode configuration selection still sometimes requires manual intervention. With expertise, distance-versus-frequency curves, which are a way to visualize the spatial relationship learned from CT between the electrodes and the nerves they stimulate, can be used to select the electrode configuration. We propose an automated technique for electrode configuration selection. A comparison between this approach and one we have previously proposed shows that our method produces results that are as good as those obtained with our previous method while being generic and requiring fewer parameters.

  14. Porous glasses as a host of luminescent materials, their applications and site selective determination

    Energy Technology Data Exchange (ETDEWEB)

    Reisfeld, Renata, E-mail: renata.reisfeld@mail.huji.ac.il [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Jasinska, Bozena [Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Skłodowsskiej 1, 20-031 Lublin (Poland); Levchenko, Viktoria [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Gorgol, Marek [Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Skłodowsskiej 1, 20-031 Lublin (Poland); Saraidarov, Tsiala; Popov, Inna [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Antropova, Tatiana [I. V. Grebenshchikov Institute of the Chemistry of Silicates, Russian Academy of Sciences, Nab. Makarova, 2, Liter B, Saint-Petersburg 199034 (Russian Federation); Rysiakiewicz-Pasek, Ewa [Institute of Physics, Wroclaw University of Technology, W. Wyspianskiego 27, 50-370 Wroclaw (Poland)

    2016-01-15

    The site selective distribution of pore sizes in pure porous glasses and glasses doped by a luminescent colorant is determined by luminescent spectroscopy, SEM, SAXS and PALS. The potential applications of the studied materials as environmental and biological sensors are outlined. We suggest how luminescent porous glasses doped by complexes of Gd can act as solid scintillators in tracing elementary particles like neutrino. - Highlights: • Porous glasses are a medium for large number of luminescent materials. • Size distribution of empty and filled pores is studied. • The validity of data obtained by different methods is analyzed.

  15. Analysis of Broad-band Frequency Selective Shielding Glass by FDTD method

    OpenAIRE

    笠嶋, 善憲; Kasashima, Yoshinori

    2010-01-01

    A frequency Selective shielding (FSS) glass is a print of many same size antennas on a sheet of glass, and it has high shielding properties for one specific frequency. In the past, the author analyzed theoretically the characteristics of the FSS, as a large scale array antenna. The FSS has narrow-band shielding characteristics. This time, the author analyzed accurately the characteristics of a FSS glass being a print of many same size dipole antennas on a sheet of glass by FDTD method. As the...

  16. Glasses

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2004-01-01

    The temperature dependence of the viscosity of most glassforming liquids is known to depart significantly from the classical Arrhenius behaviour of simple fluids. The discovery of an unexpected correlation between the extent of this departure and the Poisson ratio of the resulting glass could lead...... to new understanding of glass ageing and viscous liquid dynamics....

  17. Site selective generation of sol-gel deposits in layered bimetallic macroporous electrode architectures.

    Science.gov (United States)

    Lalo, Hélène; Bon-Saint-Côme, Yémima; Plano, Bernard; Etienne, Mathieu; Walcarius, Alain; Kuhn, Alexander

    2012-02-07

    The elaboration of an original composite bimetallic macroporous electrode containing a site-selective sol-gel deposit is reported. Regular colloidal crystals, obtained by a modified Langmuir-Blodgett approach, are used as templates for the electrogeneration of the desired metals in the form of a well-defined layered bimetallic porous electrode. This porous matrix shows a spatially modulated electroactivity which is subsequently used as a strategy for targeted electrogeneration of a sol-gel deposit, exclusively in one predefined part of the porous electrode.

  18. THERMODYNAMIC MODEL AND VISCOSITY OF SELECTED ZIRCONIA CONTAINING SILICATE GLASSES

    Directory of Open Access Journals (Sweden)

    MÁRIA CHROMČÍKOVÁ

    2013-03-01

    Full Text Available The compositional dependence of viscosity, and viscous flow activation energy of glasses with composition xNa2O∙(15-x K2O∙yCaO∙(10-yZnO∙zZrO2∙(75-zSiO2 (x = 0, 7.5, 15; y = 0, 5, 10; z = 0, 1, 3, 5, 7 was analyzed. The studied glasses were described by the thermodynamic model of Shakhmatkin and Vedishcheva considering the glass as an equilibrium ideal solution of species with stoichiometry given by the composition of stable crystalline phases of respective glass forming system. Viscosity-composition relationships were described by the regression approach considering the viscous flow activation energy and the particular isokome temperature as multilinear function of equilibrium molar amounts of system components. The classical approach where the mole fractions of individual oxides are considered as independent variables was compared with the thermodynamic model. On the basis of statistical analysis there was proved that the thermodynamic model is able to describe the composition property relationships with higher reliability. Moreover, due its better physical justification, thermodynamic model can be even used for predictive purposes.

  19. Energy Saving Glass Lamination via Selective Radio-Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Shulman, Holly S.; Allan, Shawn M.

    2009-11-11

    This Inventions and Innovations program supported the technical and commercial research and development needed to elevate Ceralink's energy saving process for flat glass lamination from bench scale to a self-supporting technology with significant potential for growth. Radio-frequency heating was any un-explored option for laminating glass prior to this program. With significant commercial success through time and energy savings in the wood, paper, and plastics industries, RF heating was found to have significant promise for the energy intensive glass lamination industry. A major technical goal of the program was to demonstrate RF lamination across a wide range of laminate sizes and materials. This was successfully accomplished, dispelling many skeptics' concerns about the abilities of the technology. Ceralink laminated panels up to 2 ft x 3 ft, with four sets processed simultaneously, in a 3 minute cycle. All major categories of interlayer materials were found to work with RF lamination. In addition to laminating glass, other materials including photovoltaic silicon solar cells, light emitting diodes, metallized glass, plastics (acrylic and polycarbonate), and ceramics (alumina) were found compatible with the RF process. This opens up a wide range of commercial opportunities beyond the initially targeted automotive industry. The dramatic energy savings reported for RF lamination at the bench scale were found to be maintained through the scale up of the process. Even at 2 ft x 3 ft panel sizes, energy savings are estimated to be at least 90% compared to autoclaving or vacuum lamination. With targeted promotion through conference presentations, press releases and internet presence, RF lamination has gained significant attention, drawing large audiences at American Ceramic Society meetings. The commercialization success of the project includes the establishment of a revenue-generating business model for providing process development and demonstrations for

  20. Selectivity coefficients of ion-selective magnesium electrodes used for simultaneous determination of magnesium and calcium ions.

    Science.gov (United States)

    Maj-Zurawska, Magdalena; Lewenstam, Andrzej

    2011-12-15

    Membrane ion-selective magnesium electrodes are commonly used to determine ionized magnesium concentration in blood serum and intracellular fluid by potentiometric clinical analyzers. The selectivity of these electrodes against calcium ion is typically insufficient to avoid calcium interference in blood serum analysis. For this reason the selectivity coefficient for calcium ion has to be studied to make possible any mathematical corrections for calcium ion influence. Existing methods relate to the thermodynamic concept of ISE response which suggest a single constant value of the selectivity coefficient and slope that are stable over the concentration ranges of calcium and magnesium ions in the samples. Unfortunately, this rarely happens, and we rather observe dependences on solution and membrane composition, readout time, matrices (anticoagulant, vial coats) that justify usage of apparent selectivities and slopes. To get the practical insight into the response of magnesium ion-selective electrodes a novel method for estimating the selectivity coefficients and the slope of the electrode characteristics is proposed. This method is an effective starting point for selecting electrodes and designing transient signal software in a potentiometric clinical analyzer. The method allows obtaining the ionized magnesium concentration in blood serum with minimal possible error by addressing the assessed targets, i.e. apparent selectivity and slope. The method is based on computer simulation and on the Nicolsky-Eisenman equation. Usually only a few iterations are needed to obtain stable congruent results. The method presented is particularly useful in conditions where is not possible to obtain calibration curve, which is typical for clinical analyzer where at most three point calibration is performed. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Selective detection and recovery of gold at tannin-immobilized non-conducting electrode

    Energy Technology Data Exchange (ETDEWEB)

    Banu, Khaleda, E-mail: kbanu@ucla.edu [Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095 (United States); Venture Business Laboratory, Center for Advanced Science and Innovation, Osaka University, Suita, Osaka 565-0871 (Japan); Shimura, Takayoshi [Venture Business Laboratory, Center for Advanced Science and Innovation, Osaka University, Suita, Osaka 565-0871 (Japan); Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University (Japan); Sadeghi, Saman, E-mail: samsadeghi@mednet.ucla.edu [Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095 (United States)

    2015-01-01

    Highlights: • Selective detection of gold at non-conducting (NC) polymer modified electrode. • Mimosa tannin oxidized on glassy carbon electrode surface as NC polymeric film. • Permselective diffusion and mediated electron transfer at NC electrode surface. • Chemical recovery of gold is due to the reducing ability of the NC polymeric film. • Adsorption capacity of Au(III) on carbon fiber was 29 ± 1.45 mg g{sup −1} at 60 °C. - Abstract: A tannin-immobilized glassy carbon electrode (TIGC) was prepared via electrochemical oxidation of the naturally occurring polyphenolic mimosa tannin, which generated a non-conducting polymeric film (NCPF) on the electrode surface. The fouling of the electrode surface by the electropolymerized film was evaluated by monitoring the electrode response of ferricyanide ions as a redox marker. The NCPF was permselective to HAuCl{sub 4}, and the electrochemical reduction of HAuCl{sub 4} to metallic gold at the TIGC electrode was evaluated by recording the reduction current during cyclic voltammetry measurement. In the mixed electrolyte containing HAuCl{sub 4} along with FeCl{sub 3} and/or CuCl{sub 2}, the NCPF remained selective toward the electrochemical reduction of HAuCl{sub 4} into the metallic state. The chemical reduction of HAuCl{sub 4} into metallic gold was also observed when the NCPF was inserted into an acidic gold solution overnight. The adsorption capacity of Au(III) on tannin-immobilized carbon fiber was 29 ± 1.45 mg g{sup −1} at 60 °C. In the presence of excess Cu(II) and Fe(III), tannin-immobilized NCPF proved to be an excellent candidate for the selective detection and recovery of gold through both electrochemical and chemical processes.

  2. Selective detection and recovery of gold at tannin-immobilized non-conducting electrode

    International Nuclear Information System (INIS)

    Banu, Khaleda; Shimura, Takayoshi; Sadeghi, Saman

    2015-01-01

    Highlights: • Selective detection of gold at non-conducting (NC) polymer modified electrode. • Mimosa tannin oxidized on glassy carbon electrode surface as NC polymeric film. • Permselective diffusion and mediated electron transfer at NC electrode surface. • Chemical recovery of gold is due to the reducing ability of the NC polymeric film. • Adsorption capacity of Au(III) on carbon fiber was 29 ± 1.45 mg g −1 at 60 °C. - Abstract: A tannin-immobilized glassy carbon electrode (TIGC) was prepared via electrochemical oxidation of the naturally occurring polyphenolic mimosa tannin, which generated a non-conducting polymeric film (NCPF) on the electrode surface. The fouling of the electrode surface by the electropolymerized film was evaluated by monitoring the electrode response of ferricyanide ions as a redox marker. The NCPF was permselective to HAuCl 4 , and the electrochemical reduction of HAuCl 4 to metallic gold at the TIGC electrode was evaluated by recording the reduction current during cyclic voltammetry measurement. In the mixed electrolyte containing HAuCl 4 along with FeCl 3 and/or CuCl 2 , the NCPF remained selective toward the electrochemical reduction of HAuCl 4 into the metallic state. The chemical reduction of HAuCl 4 into metallic gold was also observed when the NCPF was inserted into an acidic gold solution overnight. The adsorption capacity of Au(III) on tannin-immobilized carbon fiber was 29 ± 1.45 mg g −1 at 60 °C. In the presence of excess Cu(II) and Fe(III), tannin-immobilized NCPF proved to be an excellent candidate for the selective detection and recovery of gold through both electrochemical and chemical processes

  3. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Allan, Shawn M; Baranova, Inessa; Poley, Joseph; Reis, Henrique

    2012-02-27

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North

  4. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Allan, Shawn M.

    2012-02-27

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North

  5. Considering Angle Selection When Using Ultrasound Electrode Displacement Elastography to Evaluate Radiofrequency Ablation of Tissues

    Science.gov (United States)

    Li, Qiang; Chen, Pin-Yu; Wang, Chiao-Yin; Liu, Hao-Li; Teng, Jianfu

    2014-01-01

    Percutaneous radiofrequency ablation (RFA) is a minimally invasive treatment to thermally destroy tumors. Ultrasound-based electrode-displacement elastography is an emerging technique for evaluating the region of RFA-induced lesions. The angle between the imaging probe and the RFA electrode can influence electrode-displacement elastography when visualizing the ablation zone. We explored the angle effect on electrode-displacement elastography to measure the ablation zone. Phantoms embedded with meatballs were fabricated and then ablated using an RFA system to simulate RFA-induced lesions. For each phantom, a commercial ultrasound scanner with a 7.5 MHz linear probe was used to acquire raw image data at different angles, ranging from 30° to 90° at increments of 10°, to construct electrode-displacement images and facilitate comparisons with tissue section images. The results revealed that the ablation regions detected using electrode-displacement elastography were highly correlated with those from tissue section images when the angle was between 30° and 60°. However, the boundaries of lesions were difficult to distinguish, when the angle was larger than 60°. The experimental findings suggest that angle selection should be considered to achieve reliable electrode-displacement elastography to describe ablation zones. PMID:24971347

  6. Crown bridged thiacalix[4]arenes as cesium-selective ionophores in solvent polymeric membrane electrodes

    International Nuclear Information System (INIS)

    Bereczki, Robert; Csokai, Viktor; Gruen, Alajos; Bitter, Istvan; Toth, Klara

    2006-01-01

    Novel 1,3-alternate thiacalix[4]mono- and biscrown-6 ethers were studied as ionophores in poly(vinyl chloride) membrane electrodes. Their selectivity behavior was characterized with respect to large number of cations, including potential interferents in environmental samples, and the membrane composition was optimized for cesium ion response. Among the ionophores, 1,3-alternate thiacalix[4]mono(crown-6) ether showed, especially high selectivity for cesium over other alkali-metal ions. Transition and heavy metal ions did not interfere seriously with the electrode response, which indicates that the bridging sulfur atoms do not take part in the ion recognition process. The potentiometric cesium responses of all electrodes involved in this study were found close to Nernstian and the detection limits were lower than 10 -7 M. The Cs + /Na + selectivity of the different ionophore-based sensors and the solvent extraction ability of the ligands were interpreted based on the respective constants of complex formation

  7. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Shawn M. Allan; Patricia M. Strickland; Holly S. Shulman

    2009-11-11

    Ceralink Inc. developed FastFuse™, a rapid, new, energy saving process for lamination of glass and composites using radio frequency (RF) heating technology. The Inventions and Innovations program supported the technical and commercial research and development needed to elevate the innovation from bench scale to a self-supporting technology with significant potential for growth. The attached report provides an overview of the technical and commerical progress achieved for FastFuse™ during the course of the project. FastFuse™ has the potential to revolutionize the laminate manufacturing industries by replacing energy intensive, multi-step processes with an energy efficient, single-step process that allows higher throughput. FastFuse™ transmits RF energy directly into the interlayer to generate heat, eliminating the need to directly heat glass layers and the surrounding enclosures, such as autoclaves or vacuum systems. FastFuse™ offers lower start-up and energy costs (up to 90% or more reduction in energy costs), and faster cycles times (less than 5 minutes). FastFuse™ is compatible with EVA, TPU, and PVB interlayers, and has been demonstrated for glass, plastics, and multi-material structures such as photovoltaics and transparent armor.

  8. Preliminary experiments to simulate glass/electrode interactions within a Joule Ceramic Melter

    International Nuclear Information System (INIS)

    Dalton, J.T.; Paige, E.L.; Sutcliffe, P.W.

    1986-01-01

    Preliminary isothermal corrosion tests have been made on Inconel 690 coupon samples immersed in Harvest II M9 glass with and without excess additions of Li 2 O (1.5%) and RuO 2 (20%) together with TeO 2 (2%) at 1200 0 C for periods up to 100 hours. Inconel 690 corrosion and the products and ruthenium redox conditions within the glass approximate to those observed in the 1/3rd scale Joule Ceramic Melter operations. Corrosion takes place by an oxidation mechanism to form a chromium-rich surface oxide, and dissolution of this surface oxide by the surrounding glass. Additions of excess Li 2 O increase the corrosion rate of Inconel 690, whereas RuO 2 + TeO 2 are neutral. The latter however have a marked effect in lowering the room temperature resistivity by at least 5 orders of magnitude even though relatively small fraction of the RuO 2 precipitates were reduced to ruthenium metal. (author)

  9. Application of tripolar concentric electrodes and prefeature selection algorithm for brain-computer interface.

    Science.gov (United States)

    Besio, Walter G; Cao, Hongbao; Zhou, Peng

    2008-04-01

    For persons with severe disabilities, a brain-computer interface (BCI) may be a viable means of communication. Lapalacian electroencephalogram (EEG) has been shown to improve classification in EEG recognition. In this work, the effectiveness of signals from tripolar concentric electrodes and disc electrodes were compared for use as a BCI. Two sets of left/right hand motor imagery EEG signals were acquired. An autoregressive (AR) model was developed for feature extraction with a Mahalanobis distance based linear classifier for classification. An exhaust selection algorithm was employed to analyze three factors before feature extraction. The factors analyzed were 1) length of data in each trial to be used, 2) start position of data, and 3) the order of the AR model. The results showed that tripolar concentric electrodes generated significantly higher classification accuracy than disc electrodes.

  10. Iodide selective membrane electrodes based on a Molybdenum-Salen as a neutral carrier

    Energy Technology Data Exchange (ETDEWEB)

    Ghanei-Motlagh, Masoud [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Taher, Mohammad Ali, E-mail: ma_taher@yahoo.com [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ahmadi, Kyoumars [AJA University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sheikhshoaie, Iran [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

    2011-12-01

    A new polymeric membrane electrode (PME) and a coated platinum disk electrode (CPtE) based on Schiff base complex of Mo(VI) as a suitable carrier for I{sup -} ion were described. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrodes. The electrodes exhibited a Nernstian slope of 63.0 {+-} 0.5 (CPtE) and 60.3 {+-} 0.4 (PME) mV decade{sup -1} in I{sup -} ion over a wide concentration range from 7.9 x 10{sup -7} to 1.0 x 10{sup -1} M for CPtE and 9.1 x 10{sup -6} to 1.0 x 10{sup -1} M I{sup -} for PME. The potentiometric response of the electrodes was independent of the pH of the test solution in the pH range 2.0-8.5 with a fast response time (< 10 s). The process of transfer of iodide across the membrane interface was investigated by use of the AC impedance technique. The proposed sensors were successfully applied to direct determination of iodide in samples containing interfering anions, waste water and as indicator electrodes in precipitation titrations. Highlights: {yields} We study new selective membrane electrodes for iodide ions. {yields} To the best of our knowledge this is the first coated platinum disk electrode of I{sup -}. {yields} The sensors have a wide concentration range with a fast response time. {yields} Efforts have been made to improve the selectivity with the use of CPtE.

  11. Selective DNA-Mediated Assembly of Gold Nanoparticles on Electroded Substrates

    Science.gov (United States)

    2008-06-01

    might use the Watson - Crick base-pairing of DNA as a means for ultrahigh-precision engineering is well- known.5,6 The idea is to use the highly specific...Selective DNA -Mediated Assembly of Gold Nanoparticles on Electroded Substrates K. E. Sapsford,†,‡,∇ D. Park,§ E. R. Goldman,‡ E. E. Foos,| S. A...electrodes via DNA hybridization. Protocols are demonstrated for maximizing selectivity and coverage using 15mers as the active binding agents. Detailed

  12. A strategy for selective detection based on interferent depleting and redox cycling using the plane-recessed microdisk array electrodes

    International Nuclear Information System (INIS)

    Zhu Feng; Yan Jiawei; Lu Miao; Zhou Yongliang; Yang Yang; Mao Bingwei

    2011-01-01

    Highlights: → A novel strategy based on a combination of interferent depleting and redox cycling is proposed for the plane-recessed microdisk array electrodes. → The strategy break up the restriction of selectively detecting a species that exhibits reversible reaction in a mixture with one that exhibits an irreversible reaction. → The electrodes enhance the current signal by redox cycling. → The electrodes can work regardless of the reversibility of interfering species. - Abstract: The fabrication, characterization and application of the plane-recessed microdisk array electrodes for selective detection are demonstrated. The electrodes, fabricated by lithographic microfabrication technology, are composed of a planar film electrode and a 32 x 32 recessed microdisk array electrode. Different from commonly used redox cycling operating mode for array configurations such as interdigitated array electrodes, a novel strategy based on a combination of interferent depleting and redox cycling is proposed for the electrodes with an appropriate configuration. The planar film electrode (the plane electrode) is used to deplete the interferent in the diffusion layer. The recessed microdisk array electrode (the microdisk array), locating within the diffusion layer of the plane electrode, works for detecting the target analyte in the interferent-depleted diffusion layer. In addition, the microdisk array overcomes the disadvantage of low current signal for a single microelectrode. Moreover, the current signal of the target analyte that undergoes reversible electron transfer can be enhanced due to the redox cycling between the plane electrode and the microdisk array. Based on the above working principle, the plane-recessed microdisk array electrodes break up the restriction of selectively detecting a species that exhibits reversible reaction in a mixture with one that exhibits an irreversible reaction, which is a limitation of single redox cycling operating mode. The

  13. Solid-contact pH-selective electrode using multi-walled carbon nanotubes.

    Science.gov (United States)

    Crespo, Gastón A; Gugsa, Derese; Macho, Santiago; Rius, F Xavier

    2009-12-01

    Multi-walled carbon nanotubes (MWCNT) are shown to be efficient transducers of the ionic-to-electronic current. This enables the development of a new solid-contact pH-selective electrode that is based on the deposition of a 35-microm thick layer of MWCNT between the acrylic ion-selective membrane and the glassy carbon rod used as the electrical conductor. The ion-selective membrane was prepared by incorporating tridodecylamine as the ionophore, potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate as the lipophilic additive in a polymerized methylmethacrylate and an n-butyl acrylate matrix. The potentiometric response shows Nernstian behaviour and a linear dynamic range between 2.89 and 9.90 pH values. The response time for this electrode was less than 10 s throughout the whole working range. The electrode shows a high selectivity towards interfering ions. Electrochemical impedance spectroscopy and chronopotentiometry techniques were used to characterise the electrochemical behaviour and the stability of the carbon-nanotube-based ion-selective electrodes.

  14. A solid-contact pH-selective electrode based on tridodecylamine as hydrogen neutral ionophore

    Science.gov (United States)

    Zhang, Jianxin; Guo, Yixuan; Li, Shangjin; Xu, Hui

    2016-10-01

    other useful properties such as pressure and heat resistance, hydrofluoric acid resistance, and it is not as fragile as the glass electrode.

  15. A solid-contact pH-selective electrode based on tridodecylamine as hydrogen neutral ionophore

    International Nuclear Information System (INIS)

    Zhang, Jianxin; Guo, Yixuan; Li, Shangjin; Xu, Hui

    2016-01-01

    as well as some other useful properties such as pressure and heat resistance, hydrofluoric acid resistance, and it is not as fragile as the glass electrode. (paper)

  16. Multiphase, multi-electrode Joule heat computations for glass melter and in situ vitrification simulations

    International Nuclear Information System (INIS)

    Lowery, P.S.; Lessor, D.L.

    1991-02-01

    Waste glass melter and in situ vitrification (ISV) processes represent the combination of electrical thermal, and fluid flow phenomena to produce a stable waste-from product. Computational modeling of the thermal and fluid flow aspects of these processes provides a useful tool for assessing the potential performance of proposed system designs. These computations can be performed at a fraction of the cost of experiment. Consequently, computational modeling of vitrification systems can also provide and economical means for assessing the suitability of a proposed process application. The computational model described in this paper employs finite difference representations of the basic continuum conservation laws governing the thermal, fluid flow, and electrical aspects of the vitrification process -- i.e., conservation of mass, momentum, energy, and electrical charge. The resulting code is a member of the TEMPEST family of codes developed at the Pacific Northwest Laboratory (operated by Battelle for the US Department of Energy). This paper provides an overview of the numerical approach employed in TEMPEST. In addition, results from several TEMPEST simulations of sample waste glass melter and ISV processes are provided to illustrate the insights to be gained from computational modeling of these processes. 3 refs., 13 figs

  17. Selective oxidation of serotonin and norepinephrine over eriochrome cyanine R film modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Yao Hong; Li Shaoguang [Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, Fuzhou 350004 (China); Tang Yuhai [Institute of Analytical Sciences, Xi' an Jiaotong University, Xi' an 710061 (China); Chen Yan [Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, Fuzhou 350004 (China); Chen Yuanzhong [Fujian Institute of Hematology, The Affiliated Union Hospital of Fujian Medical University, Fuzhou 350001 (China)], E-Mail: chenyz@pub3.fz.fj.cn; Lin Xinhua [Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, Fuzhou 350004 (China)], E-mail: xhlin1963@sin.com

    2009-08-01

    A novel ECR-modified electrode is fabricated by electrodeposition of Eriochrome Cyanine R (ECR) at a glassy carbon (GC) electrode by cyclic voltammetry (CV) in double-distilled water. The characterization of the ECR film modified electrode is carried out by atomic force microscopy (AFM), infrared spectra (IR), spectroelectrochemistry and cyclic voltammetry. The results show that a slightly heterogeneous film formed on the surface of the modified electrode, and the calculated surface concentration of ECR is 2 x 10{sup -10} mol/cm{sup -2}. The ECR film modified GC electrode shows excellent electrocatalytic activities toward the oxidation of serotonin (5-HT) and norepinephrine (NE). Furthermore, the modified electrode can separately detect 5-HT and NE, even in the presence of 200-fold concentration of ascorbic acid (AA) and 25-fold concentration of uric acid (UA). Using differential pulse voltammetry (DPV), the peak currents of 5-HT and NE recorded in pH 7 solution are linearly dependent on their concentrations in the range of 0.05-5 {mu}M and 2-50 {mu}M, respectively. The limits of detection are 0.05 and 1.5 {mu}M for 5-HT and NE, respectively. The ECR film modified electrode can be stored stable for at least 1 week in 0.05 M PBS (pH 7) at 4 {sup o}C in a refrigerator. Owing to its excellent selectivity and sensitivity, the modified electrode could provide a promising tool for the simultaneous determination of 5-HT and NE in complex biosamples.

  18. Selective detection and recovery of gold at tannin-immobilized non-conducting electrode.

    Science.gov (United States)

    Banu, Khaleda; Shimura, Takayoshi; Sadeghi, Saman

    2015-01-01

    A tannin-immobilized glassy carbon electrode (TIGC) was prepared via electrochemical oxidation of the naturally occurring polyphenolic mimosa tannin, which generated a non-conducting polymeric film (NCPF) on the electrode surface. The fouling of the electrode surface by the electropolymerized film was evaluated by monitoring the electrode response of ferricyanide ions as a redox marker. The NCPF was permselective to HAuCl4, and the electrochemical reduction of HAuCl4 to metallic gold at the TIGC electrode was evaluated by recording the reduction current during cyclic voltammetry measurement. In the mixed electrolyte containing HAuCl4 along with FeCl3 and/or CuCl2, the NCPF remained selective toward the electrochemical reduction of HAuCl4 into the metallic state. The chemical reduction of HAuCl4 into metallic gold was also observed when the NCPF was inserted into an acidic gold solution overnight. The adsorption capacity of Au(III) on tannin-immobilized carbon fiber was 29±1.45 mg g(-1) at 60°C. In the presence of excess Cu(II) and Fe(III), tannin-immobilized NCPF proved to be an excellent candidate for the selective detection and recovery of gold through both electrochemical and chemical processes. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Determination of chloride in MOX samples using chloride ion selective electrode

    Energy Technology Data Exchange (ETDEWEB)

    Govindan, R; Das, D K; Mallik, G K; Sumathi, A; Patil, Sangeeta; Raul, Seema; Bhargava, V K; Kamath, H S [Bhabha Atomic Research Centre, Tarapur (India). Advanced Fuel Fabrication Facility

    1997-09-01

    The chloride present in the MOX fuel is separated from the matrix by pyrohydrolysis at a temperature of 950 {+-} 50 degC and is then analyzed by chloride ion selective electrode (Cl-ISE). The range covered is 0.4-4 ppm with a precision of better than {+-}5% R.S.D. (author). 4 refs., 1 tab.

  20. Selective wetting-induced micro-electrode patterning for flexible micro-supercapacitors.

    Science.gov (United States)

    Kim, Sung-Kon; Koo, Hyung-Jun; Lee, Aeri; Braun, Paul V

    2014-08-13

    Selective wetting-induced micro-electrode patterning is used to fabricate flexible micro-supercapacitors (mSCs). The resulting mSCs exhibit high performance, mechanical stability, stable cycle life, and hold great promise for facile integration into flexible devices requiring on-chip energy storage. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Determination of extractable fluoride in contaminated soils with ion-selective electrode

    OpenAIRE

    Mirlean, Nicolai; Baraj, Besnik; Garcia, Marina Reback Domingues; Niencheski, Luis Felipe Hax; Baisch, Paulo Roberto Martins; Casartelli, Maria Regina de Oliveira; Robinson, Daniel

    2003-01-01

    In a factorial design study involving the determination of F- by ion-selective electrodes, a significant interference was demonstrated for Fe, with an even more pronounced interference for Al. The fluoride leaching procedure from polluted soil showed more reliable results using 0.5 M citric acid

  2. Solid contact potassium selective electrodes for biomedical applications – a review

    NARCIS (Netherlands)

    van de Velde, Lennart; d'Angremont, E.; Olthuis, Wouter

    2016-01-01

    Ion-selective electrodes (ISE) are used in several biomedical applications, including laboratory sensing of potassium concentration in blood and urine samples. For on-site determination of potassium concentration and usage in other applications such as determination of extracellular potassium

  3. Method for fluoride routine determination in urine of personnel exposed, by ion selective electrode

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Bellintani, S.A.

    1986-01-01

    A simple, fast and sensible method is outlined for the determination of fluoride in urine of workers that handle fluorine compounds. The determination is based on the measurement of fluoride by ion selective electrode. Cationic interference like Ca ++ , Mg ++ , Fe +++ and Al +++ are complexed by EDTA and citric acid. (Author) [pt

  4. Radiation impact on the characteristics of optical glasses test results on a selected set of materials

    Science.gov (United States)

    Fruit, Michel; Gussarov, Andrei; Berghmans, Francis; Doyle, Dominic; Ulbrich, Gerd

    2017-11-01

    It is well known within the Space optics community that radiation may significantly affect transmittance of glasses. To overcome this drawback, glass manufacturers have developed Cerium doped counterparts of classical glasses. This doped glasses display much less transmittance sensitivity to radiation. Still, the impact of radiation on refractive index is less known and may affect indifferently classical or Cerium doped glasses. ESTEC has initialised an R&D program with the aim of establishing a comprehensive data base gathering radiation sensitivity data, called Dose coefficients, for all the glass optical parameters (transmittance / refractive index / compaction……). The first part of this study, to define the methodology for such a data base, is run by ASTRIUM SAS in co-operation with SCK CEN. This covers theoretical studies associated to testing of a selected set of classical and "radiation hardened" glasses. It is proposed here to present first the theoretical backgrounds of this study and then to give results which have been obtained so far.

  5. Determination of fluoride content in UO2F2 and ADUF solution by ion selective electrode

    International Nuclear Information System (INIS)

    Samanta, Papu; Kumar, Pradeep; Bagchi, A.C.

    2017-01-01

    During production of uranium metal powder, liquid solution UO 2 F 2 and ADUF containing high content of fluoride gets generated. Fluoride being corrosive in nature, fluorides concentration needs to determined. Ion selective electrode, LaF 3 (Eu) crystal, has been used. Uranium was found to interfere with fluoride analysis. Study was carried out to selectively remove uranium by solvent extraction employing D2EHPA+Cyanex 923 and TBP in dodecane. The TBP was found effective to remove uranium. (author)

  6. Selective passive adsorption of nitrate with surfactant treated porous electrode and electrostatic regeneration

    Science.gov (United States)

    Oyarzun, Diego I.; Hemmatifar, Ali; Palko, James W.; Stadermann, Michael; Santiago, Juan G.; Stanford microfluidics lab Team; Lawrence Livermore National Lab Team

    2017-11-01

    Nitrate is an important pollutant in drinking water worldwide, and a number of methods exist for the removal of nitrate from water including ion exchange and reverse osmosis. However, these approaches suffer from a variety of disadvantages including the need for a regenerating brine supply and disposal of used brine for ion exchange and low water recovery ratio for reverse osmosis. We are researching and developing a form of capacitive deionization (CDI) for energy efficient desalination and selective removal of ionic toxins from water. In CDI an electrode is used to electrostatically trap ions in a pair of porous electrodes. Here, we demonstrate the use of high surface area activated carbon electrodes functionalized with ion exchange moieties for adsorption of nitrate from aqueous solution. Unlike a traditional ion exchanger, the functionalized surfaces can be repeatedly regenerated by the application of an electrostatic potential which displaces the bound NO3- while leaving an excess of electronic charge on the electrode. Trimethylammonium has an intrinsic selectivity, we are using this moiety to selectively remove nitrate over chloride. We performed adsorption/desorption cycles under several desorption voltages and ratios of concentrations.

  7. Influence of nonionic surfactants on the potentiometric response of hydrogen ion-selective polymeric membrane electrodes.

    Science.gov (United States)

    Espadas-Torre, C; Bakker, E; Barker, S; Meyerhoff, M E

    1996-05-01

    The influence of poly(ethylene oxide)-based nonionic surfactants (i.e., Triton X-100 and Brij 35) in the sample phase on the response properties of hydrogen ion-selective polymeric membrane electrodes containing mobile (lipophilic amines) or covalently bound (aminated-poly-(vinyl chloride)) hydrogen ion carriers is reported. In the presence of these nonionic surfactants, membrane electrode response toward interfering cation activity (e.g., Na+) in the sample phase is increased substantially and the pH measuring range shortened. The degree of cation interference for pH measurements is shown to correlate with the basicity of the hydrogen ion carrier doped within the membrane phase. The observed deterioration in selectivity arises from the partitioning of the surfactant into the membrane and concomitant extraction of metal cations by the surfactants in the organic phase. The effect of nonionic surfactants on pH electrodes prepared with aminated-PVC membranes is shown to be more complex, with additional large shifts in EMF values apparently arising from multidentate interactions between the surfactant molecules and the polymeric amine in the membrane, leading to a change in the apparent pKa values for the amine sites. The effects induced by nonionic surfactants on the EMF response function of hydrogen ion-selective polymeric membrane electrodes are modeled, and experimental results are shown to correlate well with theoretical predictions.

  8. Monitoring of fluoride and iodide levels in drinking water using ion selective electrodes

    International Nuclear Information System (INIS)

    Ahmed, R.; Viqar-Un-Nisa; Hussain, M.; Tanwir, R.; Qureshi, S.A.

    2004-01-01

    Fluoride and iodide, the most important constituents of drinking water are essential as well as toxic depending on their levels. For their analysis in water mostly ion-selective electrodes, spectrophotometry, titrimetry and coulometry etc; have been used and literature has been briefly reviewed. Ion-selective electrodes offer an efficient method for the measurement of the two halides and were mostly used during this work. Fabrication of these electrodes is briefly described. Comparison of results obtained by ion selective electrode and coulometry is given. Recoveries of the added fluoride ions from the samples were good. A large number of water samples from Rawalpindi-Islamabad area were analyzed for fluoride and iodide. Levels of fluoride and iodide from two main water reservoirs of Rawalpindi and Islamabad are reported before and after treatment. Both surface and ground water samples were analyzed and results are compared and discussed. Some samples from northern areas were also analyzed for iodide and fluoride and compared. Intake of fluoride and iodide from water of different areas is also compared. Water samples, which caused bone deformation in certain areas in Punjab due to excess fluoride, were also analyzed for fluoride and results are presented. (author)

  9. Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates

    International Nuclear Information System (INIS)

    Chadderdon, Xiaotong H.; Chadderdon, David J.; Matthiesen, John E.

    2017-01-01

    Electrochemical reduction of biomass-derived platform molecules is an emerging route for the sustainable production of fuels and chemicals. Understanding gaps between reaction conditions, underlying mechanisms, and product selectivity have limited the rational design of active, stable, and selective catalyst systems. Here, the mechanisms of electrochemical reduction of furfural, an important biobased platform molecule and model for aldehyde reduction, are explored through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions of each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. By understanding the underlying mechanisms it enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important biobased polymer precursors and fuels.

  10. Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates.

    Science.gov (United States)

    Chadderdon, Xiaotong H; Chadderdon, David J; Matthiesen, John E; Qiu, Yang; Carraher, Jack M; Tessonnier, Jean-Philippe; Li, Wenzhen

    2017-10-11

    Electrochemical reduction of biomass-derived platform molecules is an emerging route for the sustainable production of fuels and chemicals. However, understanding gaps between reaction conditions, underlying mechanisms, and product selectivity have limited the rational design of active, stable, and selective catalyst systems. In this work, the mechanisms of electrochemical reduction of furfural, an important biobased platform molecule and model for aldehyde reduction, are explored through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions of each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. Understanding the underlying mechanisms enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important biobased polymer precursors and fuels.

  11. Application of graphene oxide/lanthanum-modified carbon paste electrode for the selective determination of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Fengying; Feng, Chenqi; Fu, Ning; Wu, Huihui; Jiang, Jibo, E-mail: jibojiang0506@163.com; Han, Sheng, E-mail: hansheng654321@sina.com

    2015-12-01

    Highlights: • The effective surface area of the modified CPE has been expanded after self-assembly. • The GO–La composite exhibited excellent electrocatalytic activity toward DA. • The GO–La/CPE presented high selectivity, sensitivity, excellent stability and repeatability. - Abstract: A home-made carbon paste electrode (CPE) was reformed by graphene oxide (GO)/lanthanum (La) complexes, and a modified electrode, called GO–La/CPE, was fabricated for the selective determination of dopamine (DA) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Several factors affecting the electrocatalytic performance of the modified sensor were investigated. Owning to the combination of GO and La ions, the GO–La/CPE sensor exhibited large surface area, well selectivity, good repeatability and stability in the oxidation reaction of DA. At optimal conditions, the response of the GO–La/CPE electrode for determining DA was linear in the region of 0.01–0.1 μM and 0.1–400.0 μM. The limit of detection was down to 0.32 nM (S/N = 3). In addition, this modified electrode was successfully applied to the detection of DA in real urine and serum samples by using standard adding method, showing its promising application in the electroanalysis of real samples.

  12. Behaviour of polycrystalline fluoride-selective membrane electrode in aqueous-organic media

    International Nuclear Information System (INIS)

    Manakova, L.I.; Bausova, N.V.; Moiseev, V.E.; Bamburov, V.G.; Sivoplyas, A.P.

    1978-01-01

    The behaviour of polycrystalline fluoride membrane electrode (RFME) in aqueous-organic media has been studied when the content of the organic component (methanol, ethanol, acetone, dioxane) has been changed from 20 to 80 mass%. Since LaF 3 is the base of the membrane, its solubility has been studied depending on the organic component content in the solution. It has been established that LaF 3 solubility decreases with increasing content of of the organic component. This explains the effect of the composition of an aqueous-organic solvent on the electrode sensitivity. The electrode sensitivity rises with increasing content of the organic component in an aqueous-organic solvent. A greater decrease of LaF 3 solubility in aqueous-organic solvents as compared with that of LaCl 3 , La(NO 3 ) 3 , and La 2 (SO 4 ) 3 causes a higher selectivity of RFME with respect to the anions under study

  13. Electrochemical selective detection of dopamine on microbial carbohydrate-doped multiwall carbon nanotube-modified electrodes.

    Science.gov (United States)

    Jin, Joon-Hyung; Cho, Eunae; Jung, Seunho

    2010-03-01

    Microbial carbohydrate-doped multiwall carbon nanotube (MWNT)-modified electrodes were prepared for the purpose of determining if 4-(2-aminoethyl)benzene-1,2-diol (3,4-dihydroxyphenylalanine; dopamine) exists in the presence of 0.5 mM ascorbic acid, a representative interfering agent in neurotransmitter detection. The microbial carbohydrate dopants were alpha-cyclosophorohexadecaose (alpha-C16) from Xanthomonas oryzae and cyclic-(1 --> 2)-beta-d-glucan (Cys) from Rhizobium meliloti. The cyclic voltammetric responses showed that the highest sensitivity (5.8 x 10(-3) mA cm(-2) microM(-1)) is attained with the Cys-doped MWNT-modified ultra-trace carbon electrode, and that the alpha-C16-doped MWNT-modified glassy carbon electrode displays the best selectivity to dopamine (the approximate peak potential separation is 310 mV).

  14. Development of a new all solid contact Cs"+ ion selective electrode

    International Nuclear Information System (INIS)

    Ramanjaneyulu, P.S.; Abha Naveen Kumar; Sharma, M.K.

    2017-01-01

    Studies were carried out to develop all solid contact cesium ion selective electrode with 25,27-bis(1-octyloxy)calix[4]arene-crown-6 as an ionophore. Polyaniline (PANI), deposited on Pt electrode by electrochemical method, was used as a transducer. Three different types of electrodes were made with variation in thickness of PANI film and gold nanoparticles doped PANI as transducers. The best response was observed with ISE having Au nanoparticles doped PANI as a transducer. The optimised ISE gave Nernstian response in the range 10"-"7 to 10"-"2 M with the slope of 55.0 ± 0.6 mV/decade of Cs"+. The response of ISE for Cs"+ is fairly constant above the pH 4. The developed ISE was successfully employed to determine Cs"+ in simulated high level nuclear waste solutions and CsCl spiked tap water samples. (author)

  15. Iodide selective membrane electrodes based on a Molybdenum-Salen as a neutral carrier

    International Nuclear Information System (INIS)

    Ghanei-Motlagh, Masoud; Taher, Mohammad Ali; Ahmadi, Kyoumars; Sheikhshoaie, Iran

    2011-01-01

    A new polymeric membrane electrode (PME) and a coated platinum disk electrode (CPtE) based on Schiff base complex of Mo(VI) as a suitable carrier for I - ion were described. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrodes. The electrodes exhibited a Nernstian slope of 63.0 ± 0.5 (CPtE) and 60.3 ± 0.4 (PME) mV decade -1 in I - ion over a wide concentration range from 7.9 x 10 -7 to 1.0 x 10 -1 M for CPtE and 9.1 x 10 -6 to 1.0 x 10 -1 M I - for PME. The potentiometric response of the electrodes was independent of the pH of the test solution in the pH range 2.0-8.5 with a fast response time ( - . → The sensors have a wide concentration range with a fast response time. → Efforts have been made to improve the selectivity with the use of CPtE.

  16. Effect of contacts configuration and location on selective stimulation of cuff electrode.

    Science.gov (United States)

    Taghipour-Farshi, Hamed; Frounchi, Javad; Ahmadiasl, Nasser; Shahabi, Parviz; Salekzamani, Yaghoub

    2015-01-01

    Cuff electrodes have been widely used chronically in different clinical applications. Advancements have been made in selective stimulation by using multi-contact cuff electrodes. Steering anodic current is a strategy to increase selectivity by reshaping and localizing electric fields. There are two configurations for contacts to be implemented in cuff, monopolar and tripolar. A cuff electrode with tripolar configuration can restrict the activation to a more localized region within a nerve trunk compared to a cuff with monopolar configuration and improve the selectivity. Anode contacts in tripolar configuration can be made in two structures, "ring" and "dot". In this study, the stimulation capabilities of these two structures were evaluated. The recruitment properties and the selectivity of stimulation were examined by measuring the electric potential produced by stimulation currents. The results of the present study indicated that using dot configuration, the current needed to stimulate fascicles in tripolar topologies would be reduced by 10%. It was also shown that stimulation threshold was increased by moving anode contacts inward the cuff. On the other hand, stimulation threshold was decreased by moving the anode contacts outward the cuff which would decrease selectivity, too. We conclude that dot configuration is a better choice for stimulation. Also, a cuff inward placement of 10% relative to the cuff length was near optimal.

  17. Test of freonless operation of resistive plate chambers with glass electrodes--1 mm gas gap vs 2 mm gas gap

    CERN Document Server

    Sakaue, H; Takahashi, T; Teramoto, Y

    2002-01-01

    Non-freon gas mixtures (Ar/iso-C sub 4 H sub 1 sub 0) were tested as the chamber gas for 1 and 2 mm gas gap Resistive Plate Chambers (RPCs) with float glass as the resistive electrodes, operated in the streamer mode. With the narrower (1 mm) gas gap, streamer charge is reduced (approx 1/3), which reduces the dead time (and dead area), associated with each streamer, improving the detection efficiency. The best performance was obtained for two cases: Ar/iso-C sub 4 H sub 1 sub 0 =50/50 and 60/40. For the 50/50 mixture, a detection efficiency of better than 98% was obtained for the 1 mm gap RPC, while the efficiency was 95% for the 2 mm gap RPC, each operated as a double-gap RPC. The measured time resolution (rms) was 1.45+-0.05 (2.52+-0.09) ns for the 1 (2) mm gap RPC for the 50/50 mixture.

  18. Development of phosphate glass microspheres containing holmium for selective internal radiotherapy

    International Nuclear Information System (INIS)

    Barros Filho, Eraldo Cordeiro

    2016-01-01

    The selective internal radiotherapy is an alternative for some kinds of cancer as the hepatocellular carcinoma (HCC) or primary liver cancer treatment. In this treatment, glass or polymer microspheres containing radionuclides inside their structure are introduced in the liver through hepatic artery and trapped at the arterioles that feed the tumor. In this work, the development of phosphate glasses containing holmium for production of microspheres and their application in Brazil are proposed. The developed glasses presented suitable chemical durability, density of 2,7(3) g/cm 3 , high thermal stability and the impurities contained therein do not preclude the treatment. The microspheres were produced by the flame method and the gravitational fall method, and were characterized by means of several techniques to evaluate shape, average particle size, activity and biocompatibility suitable for selective internal radiotherapy. Based in the main results, the submission to in vivo tests is proposed. (author)

  19. Cerium(III-Selective Membrane Electrode Based on Dibenzo-24-crown-8 as a Neutral Carrier

    Directory of Open Access Journals (Sweden)

    Susheel K. Mittal

    2010-01-01

    Full Text Available Cerium(III-selective membrane electrodes have been prepared using dibenzo-24-crown-8 (DB24C8 as an electroactive material. A membrane having a composition: DB24C8 (4.5%, plasticizer (NPOE, 62.5% and PVC (33% gives the best performance. It works well over a wide Ce(III ion-concentration range of 1x10-5 M to 1x10-1 M with a Nernstian slope of 19.0 mV/decade and a detection limit of 3x10-5 M. It has a fast response time of 20 seconds and has an average lifetime of four months. The internal solution concentration does not have a significant effect on the response of the electrode except for a change in intercept of the calibration curves. The working pH range for Ce(III solutions (1x10-2 M and 1x10-3 M is 3.5-8.0. The proposed sensor shows a good selectivity for cerium(III with respect to alkali, alkaline earth, some transition and rare earth metal ions that are normally present along with cerium in its ores. The proposed sensor was investigated in partially non-aqueous media using acetone, methanol and DMSO mixtures with water. The electrode was further used as an indicator electrode for the potentiometric titration of Ce(III solution against oxalic acid solution.

  20. Rapid prototyping of 2D glass microfluidic devices based on femtosecond laser assisted selective etching process

    Science.gov (United States)

    Kim, Sung-Il; Kim, Jeongtae; Koo, Chiwan; Joung, Yeun-Ho; Choi, Jiyeon

    2018-02-01

    Microfluidics technology which deals with small liquid samples and reagents within micro-scale channels has been widely applied in various aspects of biological, chemical, and life-scientific research. For fabricating microfluidic devices, a silicon-based polymer, PDMS (Polydimethylsiloxane), is widely used in soft lithography, but it has several drawbacks for microfluidic applications. Glass has many advantages over PDMS due to its excellent optical, chemical, and mechanical properties. However, difficulties in fabrication of glass microfluidic devices that requires multiple skilled steps such as MEMS technology taking several hours to days, impedes broad application of glass based devices. Here, we demonstrate a rapid and optical prototyping of a glass microfluidic device by using femtosecond laser assisted selective etching (LASE) and femtosecond laser welding. A microfluidic droplet generator was fabricated as a demonstration of a microfluidic device using our proposed prototyping. The fabrication time of a single glass chip containing few centimeter long and complex-shaped microfluidic channels was drastically reduced in an hour with the proposed laser based rapid and simple glass micromachining and hermetic packaging technique.

  1. Optimal Electrode Selection for Electrical Resistance Tomography in Carbon Fiber Reinforced Polymer Composites

    Science.gov (United States)

    Escalona Galvis, Luis Waldo; Diaz-Montiel, Paulina; Venkataraman, Satchi

    2017-01-01

    Electrical Resistance Tomography (ERT) offers a non-destructive evaluation (NDE) technique that takes advantage of the inherent electrical properties in carbon fiber reinforced polymer (CFRP) composites for internal damage characterization. This paper investigates a method of optimum selection of sensing configurations for delamination detection in thick cross-ply laminates using ERT. Reduction in the number of sensing locations and measurements is necessary to minimize hardware and computational effort. The present work explores the use of an effective independence (EI) measure originally proposed for sensor location optimization in experimental vibration modal analysis. The EI measure is used for selecting the minimum set of resistance measurements among all possible combinations resulting from selecting sensing electrode pairs. Singular Value Decomposition (SVD) is applied to obtain a spectral representation of the resistance measurements in the laminate for subsequent EI based reduction to take place. The electrical potential field in a CFRP laminate is calculated using finite element analysis (FEA) applied on models for two different laminate layouts considering a set of specified delamination sizes and locations with two different sensing arrangements. The effectiveness of the EI measure in eliminating redundant electrode pairs is demonstrated by performing inverse identification of damage using the full set and the reduced set of resistance measurements. This investigation shows that the EI measure is effective for optimally selecting the electrode pairs needed for resistance measurements in ERT based damage detection. PMID:28772485

  2. New polymeric membrane cadmium(II)-selective electrodes using tripodal amine based ionophores

    International Nuclear Information System (INIS)

    Khamjumphol, Utisawadee; Watchasit, Sarayut; Suksai, Chomchai; Janrungroatsakul, Wanwisa; Boonchiangma, Suthasinee; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2011-01-01

    Highlights: → New four ionophores having tripodal amine (TPA) unit on anthracene and calixarene. → Synthesis and characterization data were reported. → Incorporated to the plasticized PVC membranes to prepare Cd-ISEs. → Two TPA units on calixarene showed the best selectivity toward Cd 2+ . → Applied for sensing Cd 2+ from the oxidation of CdS QDs solution. - Abstract: Fabrication of PVC membrane electrodes incorporating selective neutral carriers for Cd 2+ was reported. The ionophores were designed to have different topologies, donor atoms and lipophilicity by attaching tripodal amine (TPA) units to the lipophilic anthracene (ionophore I) and p-tert-butylcalix[4]arene (ionophores II, III and IV). The synthesized ionophores were incorporated to the plasticized PVC membranes to prepare Cd(II) ion selective electrodes (ISEs). The membrane electrodes were optimized by changing types and amounts of ionic sites and plasticizers. The selectivity of the membranes fabricated from the synthesized ionophores was evaluated, the relationship between structures of ionophores and membrane characteristics were explored. The ionophore IV which composed of two opposites TPA units on the calix[4]arene compartment showed the best selectivity toward Cd 2+ . The best membrane electrode was fabricated from ionophore IV (10.2 mmol kg -1 ) with KTpClPB (50.1 mol% related to the ionophore) as an ion exchanger incorporated in the DOS plasticized PVC membrane (1:2; PVC:DOS). The Cd-ISE fabricated from ionophore IV exhibited good properties with a Nernstian response of 29.4 ± 0.6 mV decade -1 of activity for Cd 2+ ions and a working concentration range of 1.6 x 10 -6 -1.0 x 10 -2 M. The sensor has a fast response time of 10 s and can be used for at least 1 week without any divergence in potential. The electrode can be used in the pH range of 6.0-9.0. The proposed electrodes using ionophores III and IV were employed as a probe for determining Cd 2+ from the oxidation of CdS QDs

  3. New polymeric membrane cadmium(II)-selective electrodes using tripodal amine based ionophores

    Energy Technology Data Exchange (ETDEWEB)

    Khamjumphol, Utisawadee [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Watchasit, Sarayut [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Suksai, Chomchai [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Burapha University, Chonburi 20131 (Thailand); Janrungroatsakul, Wanwisa [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Boonchiangma, Suthasinee [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Tuntulani, Thawatchai [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Ngeontae, Wittaya, E-mail: wittayange@kku.ac.th [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Research Center for Environmental and Hazardous Substance Management, Khon Kaen University, Khon Kaen 40002 (Thailand); National Center of Excellence for Environmental and Hazardous Waste Management, Khon Kaen University, Khon Kaen 40002 (Thailand)

    2011-10-17

    Highlights: {yields} New four ionophores having tripodal amine (TPA) unit on anthracene and calixarene. {yields} Synthesis and characterization data were reported. {yields} Incorporated to the plasticized PVC membranes to prepare Cd-ISEs. {yields} Two TPA units on calixarene showed the best selectivity toward Cd{sup 2+}. {yields} Applied for sensing Cd{sup 2+} from the oxidation of CdS QDs solution. - Abstract: Fabrication of PVC membrane electrodes incorporating selective neutral carriers for Cd{sup 2+} was reported. The ionophores were designed to have different topologies, donor atoms and lipophilicity by attaching tripodal amine (TPA) units to the lipophilic anthracene (ionophore I) and p-tert-butylcalix[4]arene (ionophores II, III and IV). The synthesized ionophores were incorporated to the plasticized PVC membranes to prepare Cd(II) ion selective electrodes (ISEs). The membrane electrodes were optimized by changing types and amounts of ionic sites and plasticizers. The selectivity of the membranes fabricated from the synthesized ionophores was evaluated, the relationship between structures of ionophores and membrane characteristics were explored. The ionophore IV which composed of two opposites TPA units on the calix[4]arene compartment showed the best selectivity toward Cd{sup 2+}. The best membrane electrode was fabricated from ionophore IV (10.2 mmol kg{sup -1}) with KTpClPB (50.1 mol% related to the ionophore) as an ion exchanger incorporated in the DOS plasticized PVC membrane (1:2; PVC:DOS). The Cd-ISE fabricated from ionophore IV exhibited good properties with a Nernstian response of 29.4 {+-} 0.6 mV decade{sup -1} of activity for Cd{sup 2+} ions and a working concentration range of 1.6 x 10{sup -6}-1.0 x 10{sup -2} M. The sensor has a fast response time of 10 s and can be used for at least 1 week without any divergence in potential. The electrode can be used in the pH range of 6.0-9.0. The proposed electrodes using ionophores III and IV were employed

  4. Curved Microneedle Array-Based sEMG Electrode for Robust Long-Term Measurements and High Selectivity

    Directory of Open Access Journals (Sweden)

    Minjae Kim

    2015-07-01

    Full Text Available Surface electromyography is widely used in many fields to infer human intention. However, conventional electrodes are not appropriate for long-term measurements and are easily influenced by the environment, so the range of applications of sEMG is limited. In this paper, we propose a flexible band-integrated, curved microneedle array electrode for robust long-term measurements, high selectivity, and easy applicability. Signal quality, in terms of long-term usability and sensitivity to perspiration, was investigated. Its motion-discriminating performance was also evaluated. The results show that the proposed electrode is robust to perspiration and can maintain a high-quality measuring ability for over 8 h. The proposed electrode also has high selectivity for motion compared with a commercial wet electrode and dry electrode.

  5. Direct electrochemistry of glucose oxidase and a biosensor for glucose based on a glass carbon electrode modified with MoS2 nanosheets decorated with gold nanoparticles

    International Nuclear Information System (INIS)

    Su, Shao; Sun, Haofan; Xu, Fei; Yuwen, Lihui; Wang, Lianhui; Fan, Chunhai

    2014-01-01

    An electrochemical glucose biosensor was developed by immobilizing glucose oxidase (GOx) on a glass carbon electrode that was modified with molybdenum disulfide (MoS 2 ) nanosheets that were decorated with gold nanoparticles (AuNPs). The electrochemical performance of the modified electrode was investigated by cyclic voltammetry, and it is found that use of the AuNPs-decorated MoS 2 nanocomposite accelerates the electron transfer from electrode to the immobilized enzyme. This enables the direct electrochemistry of GOx without any electron mediator. The synergistic effect the MoS 2 nanosheets and the AuNPs result in excellent electrocatalytic activity. Glucose can be detected in the concentration range from 10 to 300 μM, and down to levels as low as 2.8 μM. The biosensor also displays good reproducibility and long-term stability, suggesting that it represents a promising tool for biological assays. (author)

  6. Liquid membrane ion-selective electrodes for potentiometric dosage of coper and nickel

    Directory of Open Access Journals (Sweden)

    MARIA PLENICEANY

    2005-02-01

    Full Text Available This paper presents experimental and theoretical data regarding the preparation and characterization of three liquid-membrane electrodes, which have not been mentioned in the specialized literature so far. The active substances, the solutions of which in nitrobenzene formed the membranes on a graphite rod, are simple complex combinations of Cu(II and Ni(II ions with an organic ligand belonging to the Schiff base class: N-[2-thienylmethilidene]-2-aminoethanol (TNAHE. The Cu2+ -selective and Ni2+ -selective electrodes were used to determine the copper and nickel ions in aqueous solutions, both by direct potentiometry and by potentiometric titration with EDTA. They were also used for the determination of Cu2+ and Ni2+ ions in industrial waters by direct potentiometry.

  7. A calixarene-based ion-selective electrode for thallium(I) detection

    Energy Technology Data Exchange (ETDEWEB)

    Chester, Ryan [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Sohail, Manzar [Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia); Ogden, Mark I.; Mocerino, Mauro [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Pretsch, Ernö [ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics (IBP), Universitätstrasse 16, CH-8092, Zürich (Switzerland); De Marco, Roland, E-mail: rdemarc1@usc.edu.au [Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia); Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4556 (Australia)

    2014-12-03

    Highlights: • Tuning of metal binding cavities in thallium(I) calixarene ionophores. • Novel calixarene-based ionophores with improved selectivity for thallium(I). • Sandwich membrane characterization of thallium(I) binding in novel calixarenes. • Improved selectivity and sensitivity with novel thallium(I) calixarene ionophores. • Solid contact ion-selective electrodes for novel thallium(I) calixarene ionophores. - Abstract: Three new calixarene Tl{sup +} ionophores have been utilized in Tl{sup +} ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10{sup −2}–10{sup −6} M TlNO{sub 3} with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (log β{sub IL}) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn{sup 2+}, Ca{sup 2+}, Ba{sup 2+}, Cu{sup 2+}, Cd{sup 2+} and Al{sup 3+} with moderate selectivity against Pb{sup 2+}, Li{sup +}, Na{sup +}, H{sup +}, K{sup +}, NH{sub 4}{sup +} and Cs{sup +}, noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8 nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)–poly(decyl methacrylate) (PMMA–PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4 mV decade

  8. A calixarene-based ion-selective electrode for thallium(I) detection

    International Nuclear Information System (INIS)

    Chester, Ryan; Sohail, Manzar; Ogden, Mark I.; Mocerino, Mauro; Pretsch, Ernö; De Marco, Roland

    2014-01-01

    Highlights: • Tuning of metal binding cavities in thallium(I) calixarene ionophores. • Novel calixarene-based ionophores with improved selectivity for thallium(I). • Sandwich membrane characterization of thallium(I) binding in novel calixarenes. • Improved selectivity and sensitivity with novel thallium(I) calixarene ionophores. • Solid contact ion-selective electrodes for novel thallium(I) calixarene ionophores. - Abstract: Three new calixarene Tl + ionophores have been utilized in Tl + ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10 −2 –10 −6 M TlNO 3 with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (log β IL ) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn 2+ , Ca 2+ , Ba 2+ , Cu 2+ , Cd 2+ and Al 3+ with moderate selectivity against Pb 2+ , Li + , Na + , H + , K + , NH 4 + and Cs + , noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8 nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)–poly(decyl methacrylate) (PMMA–PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4 mV decade −1 and a lower detection limit of 30.2 nM. Due to the presence of an undesirable

  9. Method for routine determination of fluoride in urine by selective ion- electrode

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Bellintani, S.A.

    1985-01-01

    A simple, fast and sensitive method is outlined for determining fluoride in urine of workers who handle fluoride compounds. The determination is based on the measurement of fluoride by ion selective electrode. Cationic interferents like Ca ++ , Mg ++ , Fe +++ and Al +++ are complexed by EDTA and citric acid. Common anions present in urine, such as Cl - , PO --- 4 and SO -- 4 do not interfere in the method. (Author) [pt

  10. Potentiometric determination of sulfate with EDTA and the cupric-selective electrode

    International Nuclear Information System (INIS)

    Baumann, E.W.

    1976-11-01

    Sulfate was indirectly determined by precipitating sulfate as BaSO 4 and then dissolving BaSO 4 in excess ammoniacal EDTA. The excess EDTA was titrated potentiometrically with La 3+ . A cupric-selective electrode was used to detect the end point. About 10 -3 M SO 4 2- was determined in 3M HCl solutions of metal oxides with a relative standard deviation of 3.5 percent and a bias of +4 percent

  11. The use of selective electrodes for the control of nuclear materials

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Abrao, A.

    1984-01-01

    The use of ion selective electrodes is discussed for the determination of nitrate, chloride and fluoride in several materials used in the fuel cycle. The determination of nitrate and chloride in thorium compounds, the analysis of fluoride and chloride in uranium compounds and the determination of fluoride in crude phosphoric acid are described. The control of fluoride in urine of individuals that handle materials containing fluor and its compounds is also described. (C.L.B.) [pt

  12. Tetraazacyclohexadeca Macrocyclic Ligand as a Neutral Carrier in a Cr Ion-selective Electrode

    Directory of Open Access Journals (Sweden)

    Puja Saxena

    2004-12-01

    Full Text Available Abstract: A polystyrene-based membrane of 2,10-dimethyl-4,12-diphenyl-1,5,9,13-tetraazacyclohexadeca-1,4,9,12-tetraene macrocyclic ionophore was prepared and investigated as Cr(III-selective electrode. The best performance was observed with the membrane having the polystyrene-ligand-dibutylphthalate-sodiumtetraphenyl borate composition 1:4:1:1 with a Nernstian slope of 19.0 mV per decade of concentration between pH 3.0 and 6.5. This electrode has been found to be chemically inert and of adequate stability with a response time of 20 s and was used over a period of 100 d with good reproducibility (S= 0.3 mV. The membrane works satisfactorily in a partially non-aqueous medium up to a maximum 30% (v/v content of methanol and ethanol. The potentiometric selectivity coefficient values indicate that the membrane sensor is highly selective for Cr(III ions over a number of monovalent, divalent and trivalent cations. The membrane electrode has also been successfully used to determine Cr3+ in various food materials.

  13. A Reagentless Amperometric Formaldehyde-Selective Chemosensor Based on Platinized Gold Electrodes.

    Science.gov (United States)

    Demkiv, Olha; Smutok, Oleh; Gonchar, Mykhailo; Nisnevitch, Marina

    2017-05-06

    Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde analysis based on platinized gold electrodes is described. The platinization process was performed electrochemically on the surface of 4 mm gold planar electrodes by both electrolysis and cyclic voltamperometry. The produced electrodes were characterized using scanning electron microscopy and X-ray spectral analysis. Using a low working potential (0.0 V vs. Ag/AgCl) enabled an essential increase in the chemosensor's selectivity for the target analyte. The sensitivity of the best chemosensor prototype to formaldehyde is uniquely high (28180 A·M -1 ·m -2 ) with a detection limit of 0.05 mM. The chemosensor remained stable over a one-year storage period. The formaldehye-selective chemosensor was tested on samples of commercial preparations. A high correlation was demonstrated between the results obtained by the proposed chemosensor, chemical and enzymatic methods ( R = 0.998). The developed formaldehyde-selective amperometric chemosensor is very promising for use in industry and research, as well as for environmental control.

  14. ENHANCED DOE HIGH LEVEL WASTE MELTER THROUGHPUT STUDIES: SRNL GLASS SELECTION STRATEGY

    Energy Technology Data Exchange (ETDEWEB)

    Raszewski, F; Tommy Edwards, T; David Peeler, D

    2008-01-23

    The Department of Energy has authorized a team of glass formulation and processing experts at the Savannah River National Laboratory (SRNL), the Pacific Northwest National Laboratory (PNNL), and the Vitreous State Laboratory (VSL) at Catholic University of America to develop a systematic approach to increase high level waste melter throughput (by increasing waste loading with minimal or positive impacts on melt rate). This task is aimed at proof-of-principle testing and the development of tools to improve waste loading and melt rate, which will lead to higher waste throughput. Four specific tasks have been proposed to meet these objectives (for details, see WSRC-STI-2007-00483): (1) Integration and Oversight, (2) Crystal Accumulation Modeling (led by PNNL)/Higher Waste Loading Glasses (led by SRNL), (3) Melt Rate Evaluation and Modeling, and (4) Melter Scale Demonstrations. Task 2, Crystal Accumulation Modeling/Higher Waste Loading Glasses is the focus of this report. The objective of this study is to provide supplemental data to support the possible use of alternative melter technologies and/or implementation of alternative process control models or strategies to target higher waste loadings (WLs) for the Defense Waste Processing Facility (DWPF)--ultimately leading to higher waste throughputs and a reduced mission life. The glass selection strategy discussed in this report was developed to gain insight into specific technical issues that could limit or compromise the ability of glass formulation efforts to target higher WLs for future sludge batches at the Savannah River Site (SRS). These technical issues include Al-dissolution, higher TiO{sub 2} limits and homogeneity issues for coupled-operations, Al{sub 2}O{sub 3} solubility, and nepheline formation. To address these technical issues, a test matrix of 28 glass compositions has been developed based on 5 different sludge projections for future processing. The glasses will be fabricated and characterized based on

  15. Non-invasive method for selection of electrodes and stimulus parameters for FES applications with intrafascicular arrays

    Science.gov (United States)

    Dowden, B. R.; Frankel, M. A.; Normann, R. A.; Clark, G. A.

    2012-02-01

    High-channel-count intrafascicular electrode arrays provide comprehensive and selective access to the peripheral nervous system. One practical difficulty in using several electrode arrays to evoke coordinated movements in paralyzed limbs is the identification of the appropriate stimulation channels and stimulus parameters to evoke desired movements. Here we present the use of a six degree-of-freedom load cell placed under the foot of a feline to characterize the muscle activation produced by three 100-electrode Utah Slanted Electrode Arrays (USEAs) implanted into the femoral nerves, sciatic nerves, and muscular branches of the sciatic nerves of three cats. Intramuscular stimulation was used to identify the endpoint force directions produced by 15 muscles of the hind limb, and these directions were used to classify the forces produced by each intrafascicular USEA electrode as flexion or extension. For 451 USEA electrodes, stimulus intensities for threshold and saturation muscle forces were identified, and the 3D direction and linearity of the force recruitment curves were determined. Further, motor unit excitation independence for 198 electrode pairs was measured using the refractory technique. This study demonstrates the utility of 3D endpoint force monitoring as a simple and non-invasive metric for characterizing the muscle-activation properties of hundreds of implanted peripheral nerve electrodes, allowing for electrode and parameter selection for neuroprosthetic applications.

  16. Highly selective direct determination of chlorate ions by using a newly developed potentiometric electrode based on modified smectite.

    Science.gov (United States)

    Topcu, Cihan

    2016-12-01

    A novel polyvinyl chloride membrane chlorate (ClO 3 - ) selective electrode based on modified smectite was developed for the direct determination of chlorate ions and the potentiometric performance characteristics of its were examined. The best selectivity and sensitivity for chlorate ions were obtained for the electrode membrane containing ionophore/polyvinylchloride/o-nitrophenyloctylether in composition of 12/28/60 (w/w%). The proposed electrode showed a Nernstian response toward chlorate ions at pH=7 in the concentration range of 1×10 -7 -1×10 -1 M and the limit of detection was calculated as 9×10 -8 M from the constructed response plot. The linear slope of the electrode was -61±1mVdecade -1 for chlorate activity in the mentioned linear working range. The selectivity coefficients were calculated according to both the matched potential method and the separate solution method. The calculated selectivity coefficients showed that the electrode performed excellent selectivity for chlorate ions. The potentiometric response of electrode toward chlorate ions was found to be highly reproducible. The electrode potential was stable between pH=4-10 and it had a dynamic response time of <5s. The potentiometric behavior of the electrode in partial non-aqueous medium was also investigated and the obtained results (up to 5% (v/v) alcohol) were satisfactory. The proposed electrode was used during 15 weeks without any significant change in its potential response. Additionally, the electrode was very useful in water analysis studies such as dam water, river water, tap water, and swimming pool water where the direct determination of chlorate ions was required. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. The glass cliff: when and why women are selected as leaders in crisis contexts.

    Science.gov (United States)

    Bruckmüller, Susanne; Branscombe, Nyla R

    2010-09-01

    The glass cliff refers to women being more likely to rise to positions of organizational leadership in times of crisis than in times of success, and men being more likely to achieve those positions in prosperous times. We examine the role that (a) a gendered history of leadership and (b) stereotypes about gender and leadership play in creating the glass cliff. In Expt 1, participants who read about a company with a male history of leadership selected a male future leader for a successful organization, but chose a female future leader in times of crisis. This interaction--between company performance and gender of the preferred future leader--was eliminated for a counter-stereotypic history of female leadership. In Expt 2, stereotypically male attributes were most predictive of leader selection in a successful organization, while stereotypically female attributes were most predictive in times of crisis. Differences in the endorsement of these stereotypes, in particular with regard to the ascription of lower stereotypically female attributes to the male candidate mediated the glass cliff effect. Overall, results suggest that stereotypes about male leadership may be more important for the glass cliff effect than stereotypes about women and leadership.

  18. Trace analysis of cyanide by ion-selective electrode indicator technique

    International Nuclear Information System (INIS)

    Tom, R.L.; Kapauan, P.A.

    1977-01-01

    Due to the toxicity of cyanide, its analysis in water is important. The use of ion-selective electrodes for its determination was studied. The known addition method using a silver sulfide membrane electrode was studied. This involved using a silver indicator solution to determine the cyanide content of a sample. Known amounts of a standard cyanide solution were added and the potentials noted. The results were plotted and the original concentration of cyanide extrapolated. The results of the experiment indicated the method to be practical for analysis of industrial waste waters, even in the presence of metal ions. The metal ions were masked using an EDTA solution while possible sulfides were precipitated out using a Pb (N0 3 ) 2 solution. The method was tested on four actual samples and the results indicated the applicability of the method

  19. New Signal Readout Principle for Solid-Contact Ion-Selective Electrodes.

    Science.gov (United States)

    Vanamo, Ulriika; Hupa, Elisa; Yrjänä, Ville; Bobacka, Johan

    2016-04-19

    A novel approach to signal transduction concerning solid-contact ion-selective electrodes (SC-ISE) with a conducting polymer (CP) as the solid contact is investigated. The method presented here is based on constant potential coulometry, where the potential of the SC-ISE vs the reference electrode is kept constant using a potentiostat. The change in the potential at the interface between the ion-selective membrane (ISM) and the sample solution, due to the change in the activity of the primary ion, is compensated with a corresponding but opposite change in the potential of the CP solid contact. This enforced change in the potential of the solid contact results in a transient reducing/oxidizing current flow through the SC-ISE. By measuring and integrating the current needed to transfer the CP to a new state of equilibrium, the total cumulated charge that is linearly proportional to the change of the logarithm of the primary ion activity is obtained. In this work, different thicknesses of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) were used as solid contact. Also, coated wire electrodes (CWEs) were included in the study to show the general validity of the new approach. The ISM employed was selective for K(+) ions, and the selectivity of the membrane under implementation of the presented transduction mechanism was confirmed by measurements performed with a constant background concentration of Na(+) ions. A unique feature of this signal readout principle is that it allows amplification of the analytical signal by increasing the capacitance (film thickness) of the solid contact of the SC-ISE.

  20. Poly (Vinyl Chloride Based Ion Selective Electrode for Determination of Zr (IV Ions Based on 2, 6-Dibenzylidenecyclohexanone

    Directory of Open Access Journals (Sweden)

    Syed A. Nabi

    2008-08-01

    Full Text Available A selective poly (vinyl chloride-based membrane sensor using 2,6-Dibenzylidenecyclohexanone as an ionophore have been prepared and explored as Zr (IV selective electrode. The sensitivity, working range and response time shows a significant dependence on the concentration of ionophore. The electrode prepared with 100 mg of PVC, 10 mg of ionophore and 5 ml of dibutylthylate shows the best performance. The electrode works well in the concentration range of 1×10-1-5×10-5 with a nerstian slope 55±2 eV and response time of 18 seconds. The sensor works well over the pH range 3-6. The sensor can be used for the period of over 1 month with out deviation in response characteristics. The selectivity of the electrode was studied and it was found that the electrode exhibited good selectivity for zirconium (IV over some alkaline earth metal ions. The electrode was also used as indicator electrode for potentiometeric titration of Zr (IV ions against EDTA solution.

  1. Glass sealing

    Energy Technology Data Exchange (ETDEWEB)

    Brow, R.K.; Kovacic, L.; Chambers, R.S. [Sandia National Labs., Albuquerque, NM (United States)

    1996-04-01

    Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

  2. Development of a novel bioactive glass for air-abrasion to selectively remove orthodontic adhesives.

    Science.gov (United States)

    Taha, Ayam A; Hill, Robert G; Fleming, Padhraig S; Patel, Mangala P

    2018-05-01

    To develop a novel, bioactive glass for removing residual orthodontic adhesive via air-abrasion, following bracket debonding, and to evaluate its effectiveness against a proprietary bioactive glass 45S5(Sylc™)-air-abrasion, and a slow-speed tungsten carbide (TC) bur. Three glasses were prepared and their bioactivity was proved. One novel glass (QMAT3) was selected due to its appropriate hardness, lower than that of enamel/45S5(Sylc™). Sixty extracted human premolars were randomly assigned to adhesive removal using: (a) QMAT3-air-abrasion, (b) 45S5(Sylc™)-air-abrasion, and (c) TC bur, which were further subdivided (n = 10) based on the adhesive used (Transbond XT™ or Fuji Ortho LC™). Enamel roughness was assessed using scanning electron microscopy (SEM) and non-contact profilometry before bracket bonding, after removing residual adhesive following bracket debonding and after polishing. QMAT3 formed apatite faster (6 h) than 45S5(Sylc™) (24 h) in Tris solution. QMAT3-air-abrasion gave the lowest enamel roughness (Ra) after removing the adhesives. SEM images showed a pitted, roughened enamel surface in the TC bur group and to a lesser extent with 45S5(Sylc™), while a virtually smooth surface without any damage was observed in the QMAT3-air-abrasion group. The time taken for adhesive removal with QMAT3 was comparable to 45S5(Sylc™) but was twice as long with the TC bur. QMAT3-air-abrasion is a promising technique for selective removal of adhesives without inducing tangible enamel damage. A novel bioactive glass has been developed as an alternative to the use of TC burs for orthodontic adhesive removal.

  3. All-Solid-State Sodium-Selective Electrode with a Solid Contact of Chitosan/Prussian Blue Nanocomposite

    Directory of Open Access Journals (Sweden)

    Tanushree Ghosh

    2017-11-01

    Full Text Available Conventional ion-selective electrodes with a liquid junction have the disadvantage of potential drift. All-solid-state ion-selective electrodes with solid contact in between the metal electrode and the ion-selective membrane offer high capacitance or conductance to enhance potential stability. Solution-casted chitosan/Prussian blue nanocomposite (ChPBN was employed as the solid contact layer for an all-solid-state sodium ion-selective electrode in a potentiometric sodium ion sensor. Morphological and chemical analyses confirmed that the ChPBN is a macroporous network of chitosan that contains abundant Prussian blue nanoparticles. Situated between a screen-printed carbon electrode and a sodium-ionophore-filled polyvinylchloride ion-selective membrane, the ChPBN layer exhibited high redox capacitance and fast charge transfer capability, which significantly enhanced the performance of the sodium ion-selective electrode. A good Nernstian response with a slope of 52.4 mV/decade in the linear range from 10−4–1 M of NaCl was observed. The stability of the electrical potential of the new solid contact was tested by chronopotentiometry, and the capacitance of the electrode was 154 ± 4 µF. The response stability in terms of potential drift was excellent (1.3 µV/h for 20 h of continuous measurement. The ChPBN proved to be an efficient solid contact to enhance the potential stability of the all-solid-state ion-selective electrode.

  4. An improved method of crafting a multi-electrode spiral cuff for the selective.

    Science.gov (United States)

    Rozman, Janez; Pečlin, Polona; Ribarič, Samo; Godec, Matjaž; Burja, Jaka

    2018-01-17

    This article reviews an improved methodology and technology for crafting a multi-electrode spiral cuff for the selective activation of nerve fibres in particular superficial regions of a peripheral nerve. The analysis, structural and mechanical properties of the spot welds used for the interconnections between the stimulating electrodes and stainless-steel lead wires are presented. The cuff consisted of 33 platinum electrodes embedded within a self-curling 17-mm-long silicone spiral sheet with a nominal internal diameter of 2.5 mm. The weld was analyzed using scanning electron microscopy and nanohardness tests, while the interconnection was investigated using destructive load tests. The functionality of the cuff was tested in an isolated porcine vagus nerve. The results of the scanning electron microscopy show good alloying and none of the typical welding defects that occur between the wire and the platinum foil. The results of the destructive load tests show that the breaking loads were between 3.22 and 5 N. The results of the nanohardness testing show that the hardness of the weld was different for the particular sites on the weld sample. Finally, the results of the functional testing show that for different stimulation intensities both the compound action potential deflection and the shape are modulated.

  5. Bismuth Modified Carbon-Based Electrodes for the Determination of Selected Neonicotinoid Insecticides

    Directory of Open Access Journals (Sweden)

    Marko Rodić

    2011-05-01

    Full Text Available Two types of bismuth modified electrodes, a bismuth-film modified glassy carbon (BiF-GCE and a bismuth bulk modified carbon paste, were applied for the determination of selected nitroguanidine neonicotinoid insecticides. The method based on an ex situ prepared BiF-GCE operated in the differential pulse voltammetric (DPV mode was applied to determine clothianidin in the concentration range from 2.5 to 23 μg cm−3 with a relative standard deviation (RSD not exceeding 1.5%. The tricresyl phosphate-based carbon paste electrodes (TCP-CPEs, bulk modified with 5 and 20 w/w% of bismuth, showed a different analytical performance in the determination of imidacloprid, regarding the peak shape, potential window, and noise level. The TCP-CPE with 5% Bi was advantageous, and the developed DPV method based on it allowed the determination in the concentration range from 1.7 to 60 μg cm−3 with an RSD of 2.4%. To get a deeper insight into the morphology of the bismuth-based sensor surfaces, scanning electron microscopic measurements were performed of both the surface film and the bulk modified electrodes.

  6. Ion-selective electrodes in potentiometric titrations; a new method for processing and evaluating titration data.

    Science.gov (United States)

    Granholm, Kim; Sokalski, Tomasz; Lewenstam, Andrzej; Ivaska, Ari

    2015-08-12

    A new method to convert the potential of an ion-selective electrode to concentration or activity in potentiometric titration is proposed. The advantage of this method is that the electrode standard potential and the slope of the calibration curve do not have to be known. Instead two activities on the titration curve have to be estimated e.g. the starting activity before the titration begins and the activity at the end of the titration in the presence of large excess of titrant. This new method is beneficial when the analyte is in a complexed matrix or in a harsh environment which affects the properties of the electrode and the traditional calibration procedure with standard solutions cannot be used. The new method was implemented both in a method of linearization based on the Grans's plot and in determination of the stability constant of a complex and the concentration of the complexing ligand in the sample. The new method gave accurate results when using titrations data from experiments with samples of known composition and with real industrial harsh black liquor sample. A complexometric titration model was also developed. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Aqueous corrosion of french R7T7 nuclear waste glass: selective then congruent dissolution by pH increase

    International Nuclear Information System (INIS)

    Advocat, T.; Vernaz, E.; Crovisier, J.L.

    1991-01-01

    A study of the corrosion of a borosilicate nuclear glass shows the strong effect of the pH on the dissolution mechanism. Acidic media lead to selective extraction of the glass modifier elements (Li, Na, Ca) as well as B, while dissolution is congruent under alkaline conditions. The silica dissolution rate significantly increases with increasing pH [fr

  8. Application of drug selective electrode in the drug release study of pH-responsive microgels.

    Science.gov (United States)

    Tan, Jeremy P K; Tam, Kam C

    2007-03-12

    The colloidal phenomenon of soft particles is becoming an important field of research due to the growing interest in using polymeric system in drug delivery. Previous studies have focused on techniques that require intermediate process step such as dialysis or centrifugation, which introduces additional errors in obtaining the diffusion kinetic data. In this study, a drug selective electrode was used to directly measure the concentration of procaine hydrochloride (PrHy) released from methacrylic acid-ethyl acrylate (MAA-EA) microgel, thereby eliminating the intermediate process step. PrHy selective membrane constructed using a modified poly (vinyl chloride) (PVC) membrane and poly (ethylene-co-vinyl acetate-co-carbon monoxide) as plasticizer exhibited excellent reproducibility and stability. The response was reproducible at pH of between 3 to 8.5 and the selectivity coefficients against various organic and inorganic cations were evaluated. Drug release was conducted using the drug electrode under different pHs and the release rate increased with pH. The release behavior of the system under different pH exhibited obvious gradient release characteristics.

  9. Metalophthalocyanine complexes as ion-carriers in membrane-selective electrodes for detection of thiosalicylic acid

    International Nuclear Information System (INIS)

    Shahrokhian, Saeed; Souri, Ali

    2004-01-01

    The potentiometric response properties of several PVC-based membrane electrodes using phthalocyanine complexes of aluminum (AlPc), nickel (NiPc) and copper (CuPc) as anion carriers, toward thiosalicylic acid (TSA) were investigated. The influences of lipophilic ionic additives (cationic and anionic) and the pH of the buffered solutions were used for the interpretation of the mechanism of the potentiometric response of sensors. The sensitivity, linear range, detection limit, and potentiometric selectivity of the membrane sensors show a considerable dependence on the nature of central metal of the ionophore. The membrane electrodes based on AlPc demonstrate sub-Nernstian responses toward TSA over the range of 0.01 to 1x10 -5 M. In the case of NiPc and CuPc as ionophores and in the presence of trioctylmethyl ammonium (TOMA + ) as a cationic additive, a Nernstian response could be established in a range of 4 orders of magnitudes of TSA concentration (0.01 to 1x10 -6 M). The results of potentiometric investigations revealed that from thermodynamic point of view, the axial coordination of thiosalicylate with the central metal of NiPc and CuPc is more efficient with respect to AlPc. This preference in response to TSA was discussed on the basis of the softness nature of NiPc and CuPc and more affinity for coordination with the thiolate group of thiosalicylate as a soft anion. These potentiometric sensors manifest prominent advantages of high selectivity for TSA over the various inorganic and organic anions, fast response times and micromolar detection limits and can be used over a wide pH range of 4.0-8.0. The prepared electrodes based on NiPc and CuPc were successfully applied in the potentiometric titration of sub-milimolar quantities of Hg 2+ in aqueous solutions and very good recovery results were obtained in these measurements. The results of complexometric studies between Hg 2+ and TSA using electrodes based on NiPc and CuPc as indicator electrodes were compared with

  10. Ion-Selective Electrode for the Determination of Iron(III in Vitamin Formulations

    Directory of Open Access Journals (Sweden)

    Teixeira Marcos Fernando de S.

    1998-01-01

    Full Text Available A coated graphite-epoxy ion-selective electrode for iron(III, based on the ion-pair formed between [Fe(citrate2]3- and the tricaprylylmethylammonium cation (Aliquat 336 in a poly(vinylchloride (PVC matrix has been constructed. A thin membrane film of this ion-pair, dibutylphthalate (DBPh in PVC was deposited directly onto a Perspex® tube, which contained a graphite-epoxy conductor substrate. The coating solution was prepared by dissolving 30% (w/w of PVC in 10 mL of tetrahydrofuran following addition of 65% (w/w DBPh and 5% (w/w of the ionic pair. The effect of pH, citrate concentration and some cations on the electrode response has been investigated. The E(mV vs. log [Fe(citrate2]3- electrode response was linear for iron(III concentration from 1.0 x 10-3 mol/L to 1.0 x 10-1 mol/L in 1.0 mol/L citrate medium, with a slope of 19.3 ± 0.5 mV/decade and a useful lifetime of at least six months (more than 800 determinations for each polymeric membrane used. The detection limit was 7.5 x 10-4 mol/L and the relative standard deviation was less than 3% for a solution containing 5.0 x 10-3 mol/L of iron(III (n = 10. The application of this electrode for iron(III determination in samples of vitamin formulations is described. The results obtained with this procedure are in close agreement with those obtained using AA spectrophotometry (r = 0.9999.

  11. Determination of the total nitrate content of thorium nitrate solution with a selective electrode

    International Nuclear Information System (INIS)

    Wirkner, F.M.

    1979-01-01

    The nitrate content of thorium nitrate solutions is determined with a liquid membrane nitrate selective electrode utilizing the known addition method in 0.1 M potassium fluoride medium as ionic strength adjustor. It is studied the influence of pH and the presence of chloride, sulphate, phosphate, meta-silicate, thorium, rare earths, iron, titanium, uranium and zirconium at the same concentrations as for the aqueous feed solutions in the thorium purification process. The method is tested in synthetic samples and in samples proceeding from nitric dissolutions of thorium hidroxide and thorium oxicarbonate utilized as thorium concentrates to be purified [pt

  12. A calixarene-based ion-selective electrode for thallium(I) detection.

    Science.gov (United States)

    Chester, Ryan; Sohail, Manzar; Ogden, Mark I; Mocerino, Mauro; Pretsch, Ernö; De Marco, Roland

    2014-12-03

    Three new calixarene Tl(+) ionophores have been utilized in Tl(+) ion-selective electrodes (ISEs) yielding Nernstian response in the concentration range of 10(-2)-10(-6)M TlNO3 with a non-optimized filling solution in a conventional liquid contact ISE configuration. The complex formation constants (logβIL) for two of the calixarene derivatives with thallium(I) (i.e. 6.44 and 5.85) were measured using the sandwich membrane technique, with the other ionophore immeasurable due to eventual precipitation of the ionophore during these long-term experiments. Furthermore, the unbiased selectivity coefficients for these ionophores displayed excellent selectivity against Zn(2+), Ca(2+), Ba(2+), Cu(2+), Cd(2+) and Al(3+) with moderate selectivity against Pb(2+), Li(+), Na(+), H(+), K(+), NH4(+) and Cs(+), noting that silver was the only significant interferent with these calixarene-based ionophores. When optimizing the filling solution in a liquid contact ISE, it was possible to achieve a lower limit of detection of approximately 8nM according to the IUPAC definition. Last, the new ionophores were also evaluated in four solid-contact (SC) designs leading to Nernstian response, with the best response noted with a SC electrode utilizing a gold substrate, a poly(3-octylthiophene) (POT) ion-to-electron transducer and a poly(methyl methacrylate)-poly(decyl methacrylate) (PMMA-PDMA) co-polymer membrane. This electrode exhibited a slope of 58.4mVdecade(-1) and a lower detection limit of 30.2nM. Due to the presence of an undesirable water layer and/or leaching of redox mediator from the graphite redox buffered SC, a coated wire electrode on gold and graphite redox buffered SC yielded grossly inferior detection limits against the polypyrrole/PVC SC and POT/PMMA-PDMA SC ISEs that did not display signs of a water layer or leaching of SC ingredients into the membrane. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Determination of uranyl ion by potentiometric titration using an uranyl-selective electrode

    International Nuclear Information System (INIS)

    Nassory, N.S.

    1990-01-01

    A potentiometric titration of uranyl ion is described using an uranyl selective electrode based on a membrane containing a complex of UO 2 -bis[di-4-(1,1,3,3-tetramethylbutyl)phenyl phosphate] as an ion-exchanger and tritolyl phosphate as a solvent mediator. The titrations were carried out with various titrants: Sodium hydroxide, potassium fluoride and sodium salts of acetate, oxalate and citrate. The equivalence points were determined by Gran's method. Good results were obtained by using sodium oxalate as a titrant for the determination of uranium in several samples of ammonium diuranate. The results were quite comparable with those obtained by X-ray fluorescence spectrometry. (orig.)

  14. Determination of chlorine in nuclear-grade uranium compounds by ion-selective electrode

    International Nuclear Information System (INIS)

    Yang Chunqing; Liu Fuyun; Huang Dianfan.

    1989-01-01

    The determination of microamount chlorine in nuclear-grade uranium compounds is described. Chlorine is separated from uranium oxide pyrohydrolytically with stream of wet oxygen in a furnace at 800-900 deg C. Chlorine is volatilized as hydrochloric acid, which then is absorbed in a dilute alkaline solution and measured with chlorine selective electrode. This method covers the concentration range of 10-500 ppm chlorine in uranium oxide. The relative standard diviation is better than 10% and recovery of 85-108% has been reported

  15. A full-wafer fabrication process for glass microfluidic chips with integrated electroplated electrodes by direct bonding of dry film resist

    International Nuclear Information System (INIS)

    Vulto, Paul; Urban, G A; Huesgen, Till; Albrecht, Björn

    2009-01-01

    A full-wafer process is presented for fast and simple fabrication of glass microfluidic chips with integrated electroplated electrodes. The process employs the permanent dry film resist (DFR) Ordyl SY300 to create microfluidic channels, followed by electroplating of silver and subsequent chlorination. The dry film resist is bonded directly to a second substrate, without intermediate gluing layers, only by applying pressure and moderate heating. The process of microfluidic channel fabrication, electroplating and wafer bonding can be completed within 1 day, thus making it one of the fastest and simplest full-wafer fabrication processes. (note)

  16. Omni-directional selective shielding material based on amorphous glass coated microwires.

    Science.gov (United States)

    Ababei, G; Chiriac, H; David, V; Dafinescu, V; Nica, I

    2012-01-01

    The shielding effectiveness of the omni-directional selective shielding material based on CoFe-glass coated amorphous wires in 0.8 GHz-3 GHz microwave frequency range is investigated. The measurements were done in a controlled medium using a TEM cell and in the free space using horn antennas, respectively. Experimental results indicate that the composite shielding material can be developed with desired shielding effectiveness and selective absorption of the microwave frequency range by controlling the number of the layers and the length of microwires.

  17. Ligand substitution and selective surface coordination studies of iodine and 2,5-dihydroxythiophenol at platinum electrodes

    International Nuclear Information System (INIS)

    Berry, G.M.; Soriaga, M.P.

    1989-01-01

    The relative surface coordination strengths of 2,5-dihydroxythiophenol (DHT) and iodine at a smooth polycrystalline platinum electrode have been investigated by thin-layer electrochemical techniques. The competitive chemisorption was studied by exposing the Pt electrode to solutions of varying mole fractions of I and DHT. Studies of ligand substitution were carried out by the introduction of an iodine-coated Pt electrode into DHT solutions, and the introduction of a DHT-coated into I solutions. Surface coverage measurements indicated that DHT is preferentially adsorbed and will displace chemisorbed iodine at the Pt electrode. Chemisorbed DHT is not appreciably displaced by iodine. These results and their contribution to the trend in the selective surface coordination chemistry of platinum electrodes will be discussed

  18. Accuracy of a selection criterion for glass forming ability in the Ni–Nb–Zr system

    International Nuclear Information System (INIS)

    Déo, L.P.; Oliveira, M.F. de

    2014-01-01

    Highlights: • We applied a selection in the Ni–Nb–Zr system to find alloys with high GFA. • We used the thermal parameter γ m to evaluate the GFA of alloys. • The correlation between the γ m parameter and R c in the studied system is poor. • The effect of oxygen impurity reduced dramatically the GFA of alloys. • Unknown intermetallic compounds reduced the accuracy of the criterion. - Abstract: Several theories have been developed and applied in metallic systems in order to find the best stoichiometries with high glass forming ability; however there is no universal theory to predict the glass forming ability in metallic systems. Recently a selection criterion was applied in the Zr–Ni–Cu system and it was found some correlation between experimental and theoretical data. This criterion correlates critical cooling rate for glass formation with topological instability of stable crystalline structures; average work function difference and average electron density difference among the constituent elements of the alloy. In the present work, this criterion was applied in the Ni–Nb–Zr system. It was investigated the influence of factors not considered in the calculation and on the accuracy of the criterion, such as unknown intermetallic compounds and oxygen contamination. Bulk amorphous specimens were produced by injection casting. The amorphous nature was analyzed by X-ray diffraction and differential scanning calorimetry; oxygen contamination was quantified by the inert gas fusion method

  19. Miniaturized, Planar Ion-selective Electrodes Fabricated by Means of Thick-film Technology

    Directory of Open Access Journals (Sweden)

    Robert Koncki

    2006-04-01

    Full Text Available Various planar technologies are employed for developing solid-state sensorshaving low cost, small size and high reproducibility; thin- and thick-film technologies aremost suitable for such productions. Screen-printing is especially suitable due to itssimplicity, low-cost, high reproducibility and efficiency in large-scale production. Thistechnology enables the deposition of a thick layer and allows precise pattern control.Moreover, this is a highly economic technology, saving large amounts of the used inks. Inthe course of repetitions of the film-deposition procedure there is no waste of material dueto additivity of this thick-film technology. Finally, the thick films can be easily and quicklydeposited on inexpensive substrates. In this contribution, thick-film ion-selective electrodesbased on ionophores as well as crystalline ion-selective materials dedicated forpotentiometric measurements are demonstrated. Analytical parameters of these sensors arecomparable with those reported for conventional potentiometric electrodes. All mentionedthick-film strip electrodes have been totally fabricated in only one, fully automated thick-film technology, without any additional manual, chemical or electrochemical steps. In allcases simple, inexpensive, commercially available materials, i.e. flexible, plastic substratesand easily cured polymer-based pastes were used.

  20. Determination of lithium in organic matrix by potentiometric titration using fluoride ion selective electrode

    International Nuclear Information System (INIS)

    Govindan, R.; Alamelu, D.; Shah, Raju; Aggarwal, S.K.

    2008-01-01

    A method has been developed for the determination of lithium (Li) present in organic matrix containing hexa methylene tetramine (HMTA) and urea used in the sol-gel process for preparing lithium titanate microspheres, using fluoride ion selective electrode and potentiometric end point. Lithium is present in the wash solutions of the Sol-Gel process employed for the preparation of lithium titanate microspheres, proposed to be used in TBM (Test Blanket Module) of International Thermonuclear Experimental Reactor (ITER) project. Methods such as ICP-AES, AAS etc. used in aqueous solutions cannot be employed directly for lithium determination in organic matrix containing hexa methylene tetramine (HMTA), urea, NH 4 NO 3 , NH 4 Cl etc. A potentiometric method using a combination fluoride ion selective electrode for end point detection was developed and has been employed for lithium determination in the process streams from sol-gel process. The method is simple and rapid and an accuracy of about 0.5 % was achieved for the determination of Li in the range of 1 to 20 mg. The method is based on the complexation of Li by adding a known excess of NH 4 F solution, followed by potentiometric end point detection using fluoride ISE

  1. Spatio-selective surface modification of glass assisted by laser-induced deposition of gold nanoparticles

    International Nuclear Information System (INIS)

    Takahashi, Hironobu; Niidome, Yasuro; Hisanabe, Hideyuki; Kuroiwa, Keita; Kimizuka, Nobuo; Yamada, Sunao

    2006-01-01

    Using pulsed laser irradiation (532 nm), dodecanethiol-capped gold nanoparticles (DT-Au) were deposited on the laser-irradiated region of a hydrophobic glass substrate modified with dimethyloctadecylchlorosilane (DMOS). After removal of deposited DT-Au, the laser-deposited region on the substrate was hydrophilic, as verified by static water contact angles. X-ray photoelectron spectroscopy suggested that the naked glass surface was not exposed at the hydrophilic region. Immersion of the substrate into gold nanorod (NR) solution selectively immobilized NRs on the hydrophilic surface via electrostatic interactions, indicating that the hydrophilic region was an anionic surface. From these results, it is expected that some immobilized DMOS groups on the laser-irradiated region of the substrate were oxidized during DT-Au deposition and fragmentation of the deposited DT-Au

  2. L1-Penalized N-way PLS for subset of electrodes selection in BCI experiments

    Science.gov (United States)

    Eliseyev, Andrey; Moro, Cecile; Faber, Jean; Wyss, Alexander; Torres, Napoleon; Mestais, Corinne; Benabid, Alim Louis; Aksenova, Tetiana

    2012-08-01

    Recently, the N-way partial least squares (NPLS) approach was reported as an effective tool for neuronal signal decoding and brain-computer interface (BCI) system calibration. This method simultaneously analyzes data in several domains. It combines the projection of a data tensor to a low dimensional space with linear regression. In this paper the L1-Penalized NPLS is proposed for sparse BCI system calibration, allowing uniting the projection technique with an effective selection of subset of features. The L1-Penalized NPLS was applied for the binary self-paced BCI system calibration, providing selection of electrodes subset. Our BCI system is designed for animal research, in particular for research in non-human primates.

  3. All-solid-state ion-selective silicone rubber membrane electrodes with a new conducting polymer

    International Nuclear Information System (INIS)

    Park, Eun Rang; Chung, Yeon Joon; Hwang, Sun Woo

    2012-01-01

    New conducting polymers containing heterocyclic rings with carbazole, ethylene dioxythiophene (EDOT) and benzobisthiazole were synthesized and the characterized by using organic spectroscopic methods. Potentiometric ion-selective membrane electrodes (ISMEs) have been extensively used for ion analysis in clinical, environmental, and industrial fields owing to their wide response range (4 to 7 orders of magnitude), no effect of sample turbidity, fast response time, and ease of miniaturization. Considerable attention has been given to alternative use of room-temperature vulcanizing (RTV)-type silicone rubber (SR) owing to its strong adhesion and high thermal durability. Unfortunately, the high membrane resistance of SR-based ion-selective membranes (ISMs) (2 to 3 higher orders of magnitude compared to those of poly(vinyl chloride)(PVC)-based ones) has significantly restricted their application. Herein, we demonstrate a new method to reduce the membrane resistance via addition of a new conducting polymer into the SR-based ISMs.

  4. Selective and lithography-independent fabrication of 20 nm nano-gap electrodes and nano-channels for nanoelectrofluidics applications

    International Nuclear Information System (INIS)

    Zhang, J Y; Wang, X F; Wang, X D; Fan, Z C; Li, Y; Ji, An; Yang, F H

    2010-01-01

    A new method has been developed to selectively fabricate nano-gap electrodes and nano-channels by conventional lithography. Based on a sacrificial spacer process, we have successfully obtained sub-100-nm nano-gap electrodes and nano-channels and further reduced the dimensions to 20 nm by shrinking the sacrificial spacer size. Our method shows good selectivity between nano-gap electrodes and nano-channels due to different sacrificial spacer etch conditions. There is no length limit for the nano-gap electrode and the nano-channel. The method reported in this paper also allows for wafer scale fabrication, high throughput, low cost, and good compatibility with modern semiconductor technology.

  5. The selective electrochemical detection of homocysteine in the presence of glutathione, cysteine, and ascorbic acid using carbon electrodes.

    Science.gov (United States)

    Lee, P T; Lowinsohn, D; Compton, R G

    2014-08-07

    The detection of homocysteine, HCys, was achieved with the use of catechol via 1,4-Michael addition reaction using carbon electrodes: a glassy carbon electrode and a carbon nanotube modified glassy carbon electrode. The selective detection of homocysteine was investigated and achieved in the absence and presence of glutathione, cysteine and ascorbic acid using cyclic voltammetry and square wave voltammetry. A calibration curve of homocysteine detection was determined and the sensitivity is (0.20 ± 0.02) μA μM(-1) and the limit of detection is 660 nM within the linear range. Lastly, commercially available multi walled carbon nanotube screen printed electrodes were applied to the system for selective homocysteine detection. This work presents a potential practical application towards medical applications as it can be highly beneficial towards quality healthcare management.

  6. Ion-Selective Electrodes for the Potentiometric Determination of Pramoxine HCl Using Different Ionophores.

    Science.gov (United States)

    Ramadan, Nesrin K; Merey, Hanan A

    2012-12-01

    Four novel pramoxine HCl (PAM) selective electrodes were investigated with 2-nitrophenyl octylether as a plasticiser in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using sodium-tetraphenylborate (TPB) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl -cyclodextrin as an ionophore, while sensors 3 and 4 were constructed using 4-sulfocalix-6-arene and 4-sulfocalix-8-arene respectively as ionophores. Linear responses of PAM within the concentration ranges of 1.0 × 10-4 to 1.0 × 10-2 mol L-1 and 1.0 × 10-5 to 1.0 × 10-2 mol L-1 were obtained using sensors 1 and 2, respectively and 1.0 × 10-6 to 1.0 × 10-2 mol L-1 were obtained using sensors 3 and 4. Nernstian slopes of 50.4 ± 0.6, 54.3 ± 0.8, 56.3 ± 0.3 and 59.1 ± 0.5 mV/decade over the pH range of 3.0-6.0 were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for PAM. The utility of 2-hydroxy- propylcyclodextrin (2HP-β-CD) and 4-sulfocalix [6,8] arene (SC 6, 8) as ionophores had a significant influence on increasing the membrane sensitivity and selectivity of sensors 2, 3 and 4 compared to sensor 1. The proposed sensors displayed useful analytical characteristics for the determination of PAM in bulk powder, pharmaceutical formulation, and in biological fluid. Validation of the method showed the suitability of the proposed electrodes for the use in the quality control assessment of the drug. Furthermore, statistical comparison between the results obtained by the proposed method and the official method of the drug was performed and no significant difference was found.

  7. Potentiometric Determination of Ketotifen Fumarate in Pharmaceutical Preparations and Urine Using Carbon Paste and PVC Membrane Selective Electrodes

    Directory of Open Access Journals (Sweden)

    Eman Y. Z. Frag

    2011-01-01

    Full Text Available This study compares between unmodified carbon paste (CPE; the paste has no ion pair and polyvinyl chloride (PVC membrane selective electrodes that were used in potentiometric determination of ketotifen fumarate (KTF, where sodium tetraphenylborate (NaTPB was used as titrant. The performance characteristics of these sensors were evaluated according to IUPAC recommendations which reveal a fast, stable, and linear response for KTF over the concentration range of 10−7 to 10−2 mol L−1. The electrodes show Nernstian slope value of 52.51±0.20 and 51.51±0.25 mV decade−1 for CPE and PVC membrane electrodes at 30∘C, respectively. The potential is nearly stable over the pH range 3.0–6.0 and 2.0–7.0 for CPE and PVC membrane electrodes, respectively. Selectivity coefficient values towards different inorganic cations, sugars, and amino acids reflect high selectivity of the prepared electrodes. The electrodes responses at different temperatures were also studied, and long operational lifetime of 12 and 5 weeks for CPE and PVC membrane electrodes, respectively, were found. These are used for determination of ketotifen fumarate using potentiometric titration, calibration, and standard addition methods in pure samples, its pharmaceutical preparations (Zaditen tablets, and biological fluid (urine. The direct potentiometric determination of KTF using the proposed sensors gave recoveries % of 98.97±0.53 and 98.62±0.74 with RSD 1.42 and 0.63% for CPE and PVC membrane selective electrodes, respectively. Validation of the method shows suitability of the proposed sensors for use in quality control assessment of KTF. The obtained results were in a good agreement with those obtained using the reported spectrophotometric method.

  8. Potentiometric determination of ketotifen fumarate in pharmaceutical preparations and urine using carbon paste and PVC membrane selective electrodes.

    Science.gov (United States)

    Frag, Eman Y Z; Mohamed, Gehad G; Khalil, Mohamed M; Hwehy, Mohammad M A

    2011-01-01

    This study compares between unmodified carbon paste (CPE; the paste has no ion pair) and polyvinyl chloride (PVC) membrane selective electrodes that were used in potentiometric determination of ketotifen fumarate (KTF), where sodium tetraphenylborate (NaTPB) was used as titrant. The performance characteristics of these sensors were evaluated according to IUPAC recommendations which reveal a fast, stable, and linear response for KTF over the concentration range of 10(-7) to 10(-2) mol L(-1). The electrodes show Nernstian slope value of 52.51 ± 0.20 and 51.51 ± 0.25 mV decade(-1) for CPE and PVC membrane electrodes at 30°C, respectively. The potential is nearly stable over the pH range 3.0-6.0 and 2.0-7.0 for CPE and PVC membrane electrodes, respectively. Selectivity coefficient values towards different inorganic cations, sugars, and amino acids reflect high selectivity of the prepared electrodes. The electrodes responses at different temperatures were also studied, and long operational lifetime of 12 and 5 weeks for CPE and PVC membrane electrodes, respectively, were found. These are used for determination of ketotifen fumarate using potentiometric titration, calibration, and standard addition methods in pure samples, its pharmaceutical preparations (Zaditen tablets), and biological fluid (urine). The direct potentiometric determination of KTF using the proposed sensors gave recoveries % of 98.97 ± 0.53 and 98.62 ± 0.74 with RSD 1.42 and 0.63% for CPE and PVC membrane selective electrodes, respectively. Validation of the method shows suitability of the proposed sensors for use in quality control assessment of KTF. The obtained results were in a good agreement with those obtained using the reported spectrophotometric method.

  9. Tris(2-ethylhexyl)phosphine oxide as an effective solvent mediator for constructing a serotonin-selective membrane electrode

    International Nuclear Information System (INIS)

    Ueda, Keisuke; Yonemoto, Rei; Komagoe, Keiko; Masuda, Kazufumi; Hanioka, Nobumitsu; Narimatsu, Shizuo; Katsu, Takashi

    2006-01-01

    A series of solvent mediators containing a phosphoryl (P=O) group, such as tris(2-ethylhexyl)phosphate, bis(2-ethylhexyl) 2-ethylhexylphosphonate, 2-ethylhexyl bis(2-ethylhexyl)phosphinate, and tris(2-ethylhexyl)phosphine oxide, were used to construct serotonin-selective membrane electrodes. We found that replacing the alkoxy groups attached to phosphorus atoms in P=O groups with alkyl groups strengthened the response of the electrode to serotonin, suppressing remarkably interference from inorganic cations, such as Na + . Thus, an electrode combining tris(2-ethylhexyl)phosphine oxide with an ion-exchanger, sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate, gave a detection limit of 9 x 10 -6 M with a slope of 55.2 mV per concentration decade in physiological saline containing 150 mM NaCl and 10 mM NaH 2 PO 4 /Na 2 HPO 4 (pH 7.4). This is the best detection limit of any serotonin-selective electrode developed to date. The selectivity of this electrode for serotonin was over 10 3 times that for inorganic cations, such as Na + and K + , and lipophilic quaternary ammonium ions, such as acetylcholine and (C 2 H 5 ) 4 N + . Using the electrode, we measured the amount of serotonin released from platelets and found that the results agreed well with those obtained by a conventional fluorimetric assay of serotonin

  10. Determination of total mercury in seafood by ion-selective electrodes based on a thiol functionalized ionic liquid

    Directory of Open Access Journals (Sweden)

    Juan Miao

    2018-04-01

    Full Text Available A mercury(II ion-selective electrode with an ionic liquid (IL, 1-methyl-2-butylthioimidazolium bis(trifluoromethanesulphonylimide ([C1C4Sim]NTf2 as active material was constructed. Parameters affecting the performance of the electrodes such as the dosages of the IL and carbon nanotubes and the aqueous pH values were investigated. Experimental results indicated that the optimal composition of the electrode filling material was 47.6% [C1C4Sim]NTf2, 47.6% tetrabutylphosphonium bis(trifluoromethanesulphonylimide (TBPNTf2 and 4.8% carboxylic multi-walled carbon nanotubes (MWCNTs-COOH. Under the selected conditions, the proposed electrodes showed a good linear response in the concentration range of 10−10–10−5 mol L−1 and had a detection limit of 4.1 × 10−11 mol L−1. No great interference from common metal ions was found. The proposed electrodes were applied to determine Hg2+ in seafood samples; the results were comparable to those of the direct mercury analyzer. Keywords: Ionic liquids (ILs, Mercury, Ion-selective electrodes, Carbon nanotubes, Seafood

  11. Concentric-Electrode Organic Electrochemical Transistors: Case Study for Selective Hydrazine Sensing

    Directory of Open Access Journals (Sweden)

    Sébastien Pecqueur

    2017-03-01

    Full Text Available We report on hydrazine-sensing organic electrochemical transistors (OECTs with a design consisting of concentric annular electrodes. The design engineering of these OECTs was motivated by the great potential of using OECT sensing arrays in fields such as bioelectronics. In this work, poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS-based OECTs have been studied as aqueous sensors that are specifically sensitive to the lethal hydrazine molecule. These amperometric sensors have many relevant features for the development of hydrazine sensors, such as a sensitivity down to 10−5 M of hydrazine in water, an order of magnitude higher selectivity for hydrazine than for nine other water-soluble common analytes, the capability to entirely recover its base signal after water flushing, and a very low operation voltage. The specificity for hydrazine to be sensed by our OECTs is caused by its catalytic oxidation at the gate electrode, and enables an increase in the output current modulation of the devices. This has permitted the device-geometry study of the whole series of 80 micrometric OECT devices with sub-20-nm PEDOT:PSS layers, channel lengths down to 1 µm, and a specific device geometry of coplanar and concentric electrodes. The numerous geometries unravel new aspects of the OECT mechanisms governing the electrochemical sensing behaviours of the device—more particularly the effect of the contacts which are inherent at the micro-scale. By lowering the device cross-talk, micrometric gate-integrated radial OECTs shall contribute to the diminishing of the readout invasiveness and therefore further promote the development of OECT biosensors.

  12. Development and evaluation of holmium doped phosphate glass microspheres for selective internal radiotherapy

    International Nuclear Information System (INIS)

    Barros Filho, Eraldo C.; Martinelli, Jose Roberto; Squair, Peterson L; Osso Junior, Joao A.; Sene, Frank Ferrer

    2013-01-01

    Selective Internal Radiotherapy is used to treat hepatocellular carcinoma. In this treatment 90 Y -doped aluminosilicate glass microspheres are introduced in the hepatic artery and they migrate to the liver near to the tumor where they are trapped in the arterioles. The radiation β- emitted by the decay of 90 Y annihilates the cancer cells. A macroaggregate of albumin containing technetium is previously used to monitor the lung shunt and to prevent the spreading of 90 Y during the treatment. In the present work, 165 Ho- doped phosphate glass microspheres were developed aiming that application. 165 Ho has high cross section for neutron capture (64 bars) and 166 Ho decays emitting β- radiation with appropriate energy for killing cancer cells, and gamma rays with low energy which can be used to obtain images of the microspheres location and to check possible occurrence of lung shunt. Holmium also is highly paramagnetic and can be used to obtain images whereby NMR. The glass matrix consists of (P 2 O 5 ) tetrahedrons and can be produced by a relatively lower melting temperature of chemical compounds. The 31 P decays by emitting β- radiation and contributes to the absorbed dose, helping to annihilate the cancer cells. The microspheres were produced by using two methods: the flame and the gravitation falling methods to obtain microspheres with appropriate properties. (author)

  13. Application of membrane-selective electrodes for the determination of Tiemonium methylsulphate

    Directory of Open Access Journals (Sweden)

    Lobna A. Hussein

    2017-06-01

    Full Text Available Three ion selective electrodes were developed for the quantification of Tiemonium methylsulphate (TIM. Two of these sensors involve the construction of water insoluble ion-association complexes; namely sensor1 TIM-phosphotungstate (TIM-PT and sensor 2 TIM-Reinecke (TIM-R. Molecular recognition elements have extensive applications in electrochemical sensors with a significant potential for future development thus a third electrode utilizing molecularly imprinted polymer was constructed; sensor 3 TIM-MIP. The proposed sensors showed fast, stable Nernstian responses of 56.4, 56.1and 57.5 mV/decade for sensors 1, 2 and 3, respectively, across a relatively wide TIM concentration range (1 × 10−4 to 1 × 10−2 mol L−1 for sensors 1 and 2 and 1 × 10–5 to 1 × 10–2 mol L−1 for sensor 3 in the pH range of 2–7. Sensor 1 and sensor 2 can be used for five weeks while sensor 3 for 65 days without a significant change in sensitivity. The suggested method was used to determine TIM in dosage forms. No measurable difference was obtained when the result statistically compared with respect to accuracy and precision with reported HPLC method.

  14. (110)-Textured Ca-doped BiFeO_3 film on refined Pt(111) electrode layer on glass substrate at reduced temperature

    International Nuclear Information System (INIS)

    Chang, H.W.; Shen, C.Y.; Yuan, F.T.; Tien, S.H.; Lin, S.Y.; Chen, W.A.; Wang, C.R.; Tu, C.S.; Jen, S.U.

    2016-01-01

    Multiferroic and photovoltaic properties of polycrystalline Bi_0_._8_5Ca_0_._1_5FeO_3 (BCFO) film on refined Pt(111) electrode buffered glass substrate have been studied. Optimized Pt(111) electrode layer having large grain size and smooth morphology enables the development of highly (110)-textured BCFO film at a temperature as low as 450 °C. The prepared BCFO film has dense microstructure, fine grain size, and smooth surface morphology. Good ferroelectric properties with the remanent polarization (2P_r) of 108 μC/cm"2 and electrical coercive field of 405 kV/cm are achieved. Improved ferromagnetic properties with magnetization of 9.2 emu/cm"3 and coercivity of 1250 Oe are also attained. Significant PV properties with open-circuit photovoltage of 0.49 V and the short-circuit photocurrent of 67.4 μA/cm"2 at illumination intensity of 228 mW/cm"2 are observed, which are comparable to BCFO ceramics or BFO epitaxial films. - Highlights: • BCFO polycrystalline film with (110) texture is formed on Pt(111) electrode. • Pt(111) underlayer induces BCFO(110) film with fine grain and flat surface. • Good multiferroic and photovoltaic properties are achieved simultaneously. • Improved multiferroic and photovoltaic properties makes BCFO film a multifunctional material for advanced applications.

  15. Transverse versus longitudinal tripolar configuration for selective stimulation with multipolar cuff electrodes.

    Science.gov (United States)

    Nielsen, Thomas N; Kurstjens, G A Mathijs; Struijk, Johannes J

    2011-04-01

    The ability to stimulate subareas of a nerve selectively is highly desirable, since it has the potential of simplifying surgery to implanting one cuff on a large nerve instead of many cuffs on smaller nerves or muscles, or alternatively can improve function where surgical access to the smaller nerves is limited. In this paper, stimulation was performed with a four-channel multipolar cuff electrode implanted on the sciatic nerve of nine rabbits to compare the extensively researched longitudinal tripolar configuration with the transverse tripolar configuration, which has received less interest. The performance of these configurations was evaluated in terms of selectivity in recruitment of the three branches of the sciatic nerve. The results showed that the transverse configuration was able to selectively activate the sciatic nerve branches to a functionally relevant level in more cases than the longitudinal configuration (20/27 versus 11/27 branches) and overall achieved a higher mean selectivity [0.79 ± 0.13 versus 0.61 ± 0.09 (mean ± standard deviation)]. The transverse configuration was most successful at recruiting the small cutaneous and medium-sized peroneal branches, and less successful at recruiting the large tibial nerve.

  16. Optimization of surface morphology and scattering properties of TCO/AIT textured glass front electrode for thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Addonizio, M.L., E-mail: marialuisa.addonizio@enea.it; Fusco, L.; Antonaia, A.; Cominale, F.; Usatii, I.

    2015-12-01

    Graphical abstract: - Highlights: • Aluminium induced texture (AIT) method has been used for obtaining highly textured glass substrates. • The effect of wet etch step on morphological and optical properties has been analyzed. • The morphology features have been optimized in order to obtain the best scattering properties. • Different ZnO surface textures, depending on the underlying glass substrate structures, are obtained. • The effect of different glass texture on optical confinement has been tested in a-Si:H devices. - Abstract: Aluminium induced texture (AIT) method has been used for obtaining highly textured glass substrate suitable for silicon based thin film solar cell technology. Wet etch step parameters of AIT process have been varied and effect of different etchants and different etching times on morphological and optical properties has been analyzed. The resulting morphology features (shape, size distribution, inclination angle) have been optimized in order to obtain the best scattering properties. ZnO:Ga (GZO) films have been deposited by sputtering technique on AIT-processed glass. Two different ZnO surface morphologies have been obtained, strongly depending on the underlying glass substrate morphology induced by different etching times. Very rough and porous texture (σ{sub rms} ∼ 150 nm) was obtained on glass etched 2 min showing cauliflower-like structure, whereas a softer texture (σ{sub rms} ∼ 78 nm) was obtained on glass etched 7 min giving wider and smoother U-shaped craters. The effect of different glass textures on optical confinement has been tested in amorphous silicon based p-i-n devices. Devices fabricated on GZO/high textured glass showed a quantum efficiency enhancement due to both an effective light trapping phenomenon and an effective anti-reflective optical behaviour. Short etching time produce smaller cavities (<1 μm) with deep U-shape characterized by high roughness, high inclination angle and low autocorrelation

  17. Enhanced selectivity of boron doped diamond electrodes for the detection of dopamine and ascorbic acid by increasing the film thickness

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Yao; Long, Hangyu [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Ma, Li, E-mail: marycsupm@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Wei, Quiping, E-mail: qiupwei@csu.edu.cn [School of Material Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Li, Site [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Yu, Zhiming [School of Material Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Hu, Jingyuan [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Liu, Peizhi [Key laboratory of interface science and engineering in advanced materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024,PR China (China); Wang, Yijia [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Meng, Lingcong [Department of Chemistry, University of Warwick, Coventry, West Midlands CV4 7AL (United Kingdom)

    2016-12-30

    Highlights: • BDD electrodes with different thickness have been fabricated. • BDD electrodes are used for simultaneous detection of DA and AA. • Anodic pretreatment enhance the separation of DA and AA oxidation peak potential. • Thicker BDD electrode show better performance for DA detection coexisting with AA. - Abstract: In this paper, boron doped diamond (BDD) with different thickness were prepared by hot filament chemical vapor deposition. The performance of BDD electrodes for detecting dopamine (DA) and ascorbic acid (AA) were investigated. Scanning electron microscopy and Raman spectra reveal the grain size increases and the film quality improves with the increase of film thickness. Electrochemical test show that the transfer coefficient in [Fe{sub 3} (CN) {sub 6}]{sup 3−/4−} redox system increases with the increase of the film thickness. The results of selectivity and sensitivity for DA mixed with AA detection show that 8h-BDD and 12h-BDD electrodes possess well selective separated oxidation peaks of DA and AA, and the 12h-BDD electrode exhibits optimal sensitivity until the DA concentration drops to 1 μ M.

  18. Separation of chloride and fluoride from uranium compounds and their determination by ion selective electrodes

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Abrao, A.

    1982-01-01

    Fluoride and chloride must be rigorously controlled in uranium compounds, especially in ceramic grade UO 2 . Their determination is very difficult without previous uranium separation, particularly when both are at a low concentration. A simple procedure is described for this separation using a strong cationic resin to retain the uranyl ion. Both anions are determined in the effluent solution. Uranium compounds of nuclear fuel cycle, especially ammonium diuranate, ammonium uranyl tricarbonate, sodium diuranate, uranium trioxide and dioxide and uranium peroxide are dissolved in nitric acid and the solutions are percolated through the resin column. Chloride and fluoride are determined in the effluent by selective electrodes, the detection limits being 0.02 μg F - /ml and 1.0 μg Cl - /ml. The dissolution of the sample, the acidity of the solution, the measurement conditions and the sensitivity of the method are discussed. (Author) [pt

  19. Determining fluoride ions in ammonium desulfurization slurry using an ion selective electrode method

    Science.gov (United States)

    Luo, Zhengwei; Guo, Mulin; Chen, Huihui; Lian, Zhouyang; Wei, Wuji

    2018-02-01

    Determining fluoride ions in ammonia desulphurization slurry using a fluoride ion selective electrode (ISE) is investigated. The influence of pH was studied and the appropriate total ionic strength adjustment buffer and its dosage were optimized. The impact of Fe3+ concentration on the detection results was analyzed under preferable conditions, and the error analysis of the ISE method’s accuracy and precision for measuring fluoride ion concentration in the range of 0.5-2000 mg/L was conducted. The quantitative recovery of F- in ammonium sulfate slurry was assessed. The results showed that when pH ranged from 5.5˜6 and the Fe3+ concentration was less than 750 mg/L, the accuracy and precision test results with quantitative recovery rates of 92.0%-104.2% were obtained.

  20. Poly(vinyl chloride) membrane alkali metal ion-selective electrodes based on crystalline synthetic zeolite of the Faujasite type

    International Nuclear Information System (INIS)

    Aghai, H.; Giahi, M.; Arvand Barmehi, M.

    2002-01-01

    Potentiometric electrodes based on the incorporation of zeolite particle in to poly (vinyl chloride) (pvc) membranes are described. The electrodes characteristics are evaluated regarding the response towards alkali ions. Pvc membranes plasticised with dibutyl phthalate and without lipophilic additives (co-exchanger) were used throughout this study. The electrode exhibits a Nernst ion response over the alkali metal cations concentration a range of 1.0x10 - 4 - 1.0 x 10 1 M with a slop of 57.0 ± 0.9 mV per decade of concentration a working ph range (3.0- 9.0) and a fast response time (≤15 c). The selective coefficients for cesium ion as test species with respect to alkaline earth, ammonium and some heavy metal ions were determined. Zeolite-PVC electrodes were applied to the determination of ionic surfactant

  1. Study of the spheroidization process of glass particles for selective internal radiotherapy

    International Nuclear Information System (INIS)

    Barros Filho, Eraldo Cordeiro

    2012-01-01

    The selective internal radiotherapy is an alternative method to treat hepatocellular carcinoma. Glass microspheres containing radionuclides are introduced in the liver through the hepatic artery, and they are housed preferentially in the region where the cancer cells are located. The microspheres are trapped in the arterioles which feed the tumors, and the β - particles annihilate the cancer cells. When these particles simultaneously emit γ rays, they can also be used to provide images of the tumor. The glass particles must be spherical to avoid unnecessary bleeding, and the particle size must be restricted to a range which is appropriated to trap them and avoid the migration to other parts of the body. Furthermore, they must have a good chemical durability and be nontoxic. The particle size distribution of microspheres is not easily predicted based on the original irregular particles since the variation of the aspect ratio and the presence of agglomerates can influence the final result. In the present work, the spheroidization process to obtain microspheres for radiotherapy treatment was studied. The glass microspheres were characterized by X-rays diffraction, Energy Dispersive X-rays Fluorescence Spectroscopy, Differential Scanning Calorimetry, Specific Superficial Area and cytotoxicity test. The dissolution rate in distilled water at 90 degree C (DR∼10 -8 g.cm - 2.min -1 ), density (2.79g.cm -3 ), viscosity, and size particle distribution were determined. The surface morphological aspect was evaluated by Scanning Electron Microscopy before and after the chemical durability tests in SBF and after the neutron irradiation. It is proposed that the produced material should be sieved to select the most suitable microspheres

  2. Construction and performance characteristics of polymeric membrane electrode and coated graphite electrode for the selective determination of Fe³⁺ ion.

    Science.gov (United States)

    Bandi, Koteswara Rao; Singh, Ashok K; Upadhyay, Anjali

    2014-03-01

    Novel Fe(3+) ion-selective polymeric membrane electrodes (PMEs) were prepared using three different ionophores N-(4-(dimethylamino)benzylidene)thiazol-2-amine [L1], 5-((3-methylthiophene-2yl) methyleneamino)-1,3,4-thiadiazole-2-thiol [L2] and N-((3-methylthiophene-2yl)methylene)thiazol-2-amine [L3] and their potentiometric characteristics were discussed. Effect of various plasticizers and anion excluders was also studied in detail and improved performance was observed. The best performance was obtained for the membrane electrode having a composition of L2:PVC:o-NPOE:NaTPB as 3:38.5:56:2.5 (w/w; mg). A coated graphite electrode (CGE) was also prepared with the same composition and compared. CGE is found to perform better as it shows a wider working concentration range of 8.3×10(-8)-1.0×10(-1)molL(-1), a lower detection limit of 2.3×10(-8)molL(-1), and a near Nernstian slope of 19.5 ± 0.4 mVdecade(-1) of activity with a response time of 10s. The CGE shows a shelf life of 6 weeks and in view of high selectivity, it can be used to quantify Fe(3+) ion in water, soil, vegetable and medicinal plants. It can also be used as an indicator electrode in potentiometric titration of EDTA with Fe(3+) ion. Copyright © 2013. Published by Elsevier B.V.

  3. Stretchable, Transparent, and Stretch-Unresponsive Capacitive Touch Sensor Array with Selectively Patterned Silver Nanowires/Reduced Graphene Oxide Electrodes.

    Science.gov (United States)

    Choi, Tae Young; Hwang, Byeong-Ung; Kim, Bo-Yeong; Trung, Tran Quang; Nam, Yun Hyoung; Kim, Do-Nyun; Eom, Kilho; Lee, Nae-Eung

    2017-05-31

    Stretchable and transparent touch sensors are essential input devices for future stretchable transparent electronics. Capacitive touch sensors with a simple structure of only two electrodes and one dielectric are an established technology in current rigid electronics. However, the development of stretchable and transparent capacitive touch sensors has been limited due to changes in capacitance resulting from dimensional changes in elastomeric dielectrics and difficulty in obtaining stretchable transparent electrodes that are stable under large strains. Herein, a stretch-unresponsive stretchable and transparent capacitive touch sensor array was demonstrated by employing stretchable and transparent electrodes with a simple selective-patterning process and by carefully selecting dielectric and substrate materials with low strain responsivity. A selective-patterning process was used to embed a stretchable and transparent silver nanowires/reduced graphene oxide (AgNWs/rGO) electrode line into a polyurethane (PU) dielectric layer on a polydimethylsiloxane (PDMS) substrate using oxygen plasma treatment. This method provides the ability to directly fabricate thin film electrode lines on elastomeric substrates and can be used in conventional processes employed in stretchable electronics. We used a dielectric (PU) with a Poisson's ratio smaller than that of the substrate (PDMS), which prevented changes in the capacitance resulting from stretching of the sensor. The stretch-unresponsive touch sensing capability of our transparent and stretchable capacitive touch sensor has great potential in wearable electronics and human-machine interfaces.

  4. Stuides on a Pb2+-selective electrode with a macrocyclic liquid membrane. Potentiometric determination of Pb2+ ions

    Directory of Open Access Journals (Sweden)

    MARIAN ISVORANU

    2006-12-01

    Full Text Available This paper presents experimental and theoretical data regarding the design, characterization and analytical applications of a non-expensive, liquid-membrane ion-selective electrode for Pb2+ ions. The membrane is a solution of the active complex formed by Pb2+ ions with dibenzo-18-crown-6-ionophore (DB-[18]-C-6 extracted in propylene carbonate (PC. The sucessful application of the developed electrode for the determination of Pb2+ ions in aqueos solution samples by direct potentiometry and potentiometric titration is presented. For the presented analytical results, there are insignificant systematic errors between the direct potentiometric method with the developed ion-selective electrode and atomic absorption spectrometry.

  5. Near-infrared selective dynamic windows controlled by charge transfer impedance at the counter electrode.

    Science.gov (United States)

    Pattathil, Praveen; Scarfiello, Riccardo; Giannuzzi, Roberto; Veramonti, Giulia; Sibillano, Teresa; Qualtieri, Antonio; Giannini, Cinzia; Cozzoli, P Davide; Manca, Michele

    2016-12-08

    Recent developments in the exploitation of transparent conductive oxide nanocrystals paved the way to the realization of a new class of electrochemical systems capable of selectively shielding the infrared heat loads carried by sunlight and prospected the blooming of a key enabling technology to be implemented in the next generation of "zero-energy" building envelopes. Here we report the fabrication of a set of electrochromic devices embodying an engineered nanostructured electrode made by high aspect-ratio tungsten oxide nanorods, which allow for selectively and dynamically controlling sunlight transmission over the near-infrared to visible range. Varying the intensity of applied voltage makes the spectral response of the device change across three different optical regimes, namely fully transparent, near-infrared only blocking and both visible and near-infrared blocking. It is demonstrated that the degree of reversible modulation of the thermal radiation entering the glazing element can approach a remarkable 85%, accompanied by only a modest reduction in the luminous transmittance.

  6. Unified selective sorting approach to analyse multi-electrode extracellular data

    Science.gov (United States)

    Veerabhadrappa, R.; Lim, C. P.; Nguyen, T. T.; Berk, M.; Tye, S. J.; Monaghan, P.; Nahavandi, S.; Bhatti, A.

    2016-01-01

    Extracellular data analysis has become a quintessential method for understanding the neurophysiological responses to stimuli. This demands stringent techniques owing to the complicated nature of the recording environment. In this paper, we highlight the challenges in extracellular multi-electrode recording and data analysis as well as the limitations pertaining to some of the currently employed methodologies. To address some of the challenges, we present a unified algorithm in the form of selective sorting. Selective sorting is modelled around hypothesized generative model, which addresses the natural phenomena of spikes triggered by an intricate neuronal population. The algorithm incorporates Cepstrum of Bispectrum, ad hoc clustering algorithms, wavelet transforms, least square and correlation concepts which strategically tailors a sequence to characterize and form distinctive clusters. Additionally, we demonstrate the influence of noise modelled wavelets to sort overlapping spikes. The algorithm is evaluated using both raw and synthesized data sets with different levels of complexity and the performances are tabulated for comparison using widely accepted qualitative and quantitative indicators. PMID:27339770

  7. Ytterbium-selective polymeric membrane electrode based on substituted urea and thiourea as a suitable carrier

    International Nuclear Information System (INIS)

    Singh, A.K.; Jain, A.K.; Mehtab, Sameena

    2007-01-01

    Plasticized membranes using 1-phenyl-3-(2-thiazolyl)-2-thiourea (PTT) and 1-phenyl-3-(2-thiazolyl)-2-urea (PTU) have been prepared and explored as ytterbium ion-selective sensors. Effect of various plasticizers, viz. chloronaphthalene (CN), o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), dioctylsebacate (DOS) and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied and improved membrane performance was observed. Optimum performance was noted with membrane of PTT having composition of PTT (3.5):PVC (80):DOS (160):NaTPB (1.5) in mg. The sensor works satisfactorily in the concentration range 1.2 x 10 -7 to 1.0 x 10 -2 M (detection limit 5.5 x 10 -8 M) with a Nernstian slope of 19.7 mV decade -1 of activity. Wide pH range (3.0-8.0), fast response time (10 s), non-aqueous tolerance (up to 20%) and adequate shelf life (12 weeks) indicate the vital utility of the proposed sensor. The proposed electrode comparatively shows good selectivity for Yb 3+ ion with respect to alkali, alkaline earth, transition and rare earth metals ions and can be used for its determination in binary mixtures and sulfite determination in white and red wine samples

  8. Ytterbium-selective polymeric membrane electrode based on substituted urea and thiourea as a suitable carrier.

    Science.gov (United States)

    Singh, A K; Jain, A K; Mehtab, Sameena

    2007-08-06

    Plasticized membranes using 1-phenyl-3-(2-thiazolyl)-2-thiourea (PTT) and 1-phenyl-3-(2-thiazolyl)-2-urea (PTU) have been prepared and explored as ytterbium ion-selective sensors. Effect of various plasticizers, viz. chloronaphthalene (CN), o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), dioctylsebacate (DOS) and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied and improved membrane performance was observed. Optimum performance was noted with membrane of PTT having composition of PTT (3.5):PVC (80):DOS (160):NaTPB (1.5) in mg. The sensor works satisfactorily in the concentration range 1.2x10(-7) to 1.0x10(-2) M (detection limit 5.5x10(-8) M) with a Nernstian slope of 19.7 mV decade(-1) of activity. Wide pH range (3.0-8.0), fast response time (10 s), non-aqueous tolerance (up to 20%) and adequate shelf life (12 weeks) indicate the vital utility of the proposed sensor. The proposed electrode comparatively shows good selectivity for Yb3+ ion with respect to alkali, alkaline earth, transition and rare earth metals ions and can be used for its determination in binary mixtures and sulfite determination in white and red wine samples.

  9. Ytterbium-selective polymeric membrane electrode based on substituted urea and thiourea as a suitable carrier

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)], E-mail: akscyfcy@iitr.ernet.in; Jain, A.K.; Mehtab, Sameena [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

    2007-08-10

    Plasticized membranes using 1-phenyl-3-(2-thiazolyl)-2-thiourea (PTT) and 1-phenyl-3-(2-thiazolyl)-2-urea (PTU) have been prepared and explored as ytterbium ion-selective sensors. Effect of various plasticizers, viz. chloronaphthalene (CN), o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), dioctylsebacate (DOS) and anion excluders, sodium tetraphenylborate (NaTPB) and oleic acid (OA) was studied and improved membrane performance was observed. Optimum performance was noted with membrane of PTT having composition of PTT (3.5):PVC (80):DOS (160):NaTPB (1.5) in mg. The sensor works satisfactorily in the concentration range 1.2 x 10{sup -7} to 1.0 x 10{sup -2} M (detection limit 5.5 x 10{sup -8} M) with a Nernstian slope of 19.7 mV decade{sup -1} of activity. Wide pH range (3.0-8.0), fast response time (10 s), non-aqueous tolerance (up to 20%) and adequate shelf life (12 weeks) indicate the vital utility of the proposed sensor. The proposed electrode comparatively shows good selectivity for Yb{sup 3+} ion with respect to alkali, alkaline earth, transition and rare earth metals ions and can be used for its determination in binary mixtures and sulfite determination in white and red wine samples.

  10. Effect of the Phase Volume Ratio on the Potential of a Liquid-Membrane Ion-Selective Electrode

    Czech Academy of Sciences Publication Activity Database

    Samec, Zdeněk; Girault, H. H.

    2004-01-01

    Roč. 76, č. 14 (2004), s. 4150-4155 ISSN 0003-2700 R&D Projects: GA MŠk ME 502 Institutional research plan: CEZ:AV0Z4040901 Keywords : liquit-membrane * ion-selective electrode * two.phase liquid system Subject RIV: CG - Electrochemistry Impact factor: 5.450, year: 2004

  11. A simple, rapid and green method based on pulsed potentiostatic electrodeposition of reduced graphene oxide on glass carbon electrode for sensitive voltammetric detection of sophoridine

    International Nuclear Information System (INIS)

    Wang, Fei; Wu, Yanju; Lu, Kui; Gao, Lin; Ye, Baoxian

    2014-01-01

    Graphical abstract: A simple, rapid and green method, based on graphene nanosheets directly deposited onto a glassy carbon electrode by pulsed potentiostatic reduction of a graphene oxide colloidal solution, to build sensitive voltammetric sensor for the determination of sophoridine was presented. - Highlights: • A simple, rapid and green method to build sensitive voltammetric sensor was presented. • The proposed sensor has a high electrochemical sensitivity for determination of sophoridine. • The proposed sensor exhibited an excellent selectivity. - Abstract: A simple, rapid and green method was described for sensitive voltammetric detection of sophoridine based on graphene nanosheets directly deposited onto a glassy carbon electrode (GCE) by pulsed potentiostatic reduction of a graphene oxide (GO) colloidal solution. The resulting electrodes (PP-ERGO/GCE) were characterized by electrochemical methods and scanning electron microscopy. Moreover, the electrochemical behaviors of sophoridine at the modified electrode were investigated in detail by cyclic voltammetry (CV), chronoamperometry (CA) and chronocoulometry (CC). Compared with the bare GCE and the preparation of reduced graphene oxide (RGO) films by potentiostatic method (PM) modified GCE, PP-ERGO/GCE could intensively enhance the oxidation peak currents and decrease the overpotential of sophoridine. Under the selected conditions, the modified electrode showed a linear voltammetric response to sophoridine within the concentration range of 8.0 × 10 −7 ∼ 1.0 × 10 −4 mol L −11 , with the detection limit of 2.0 × 10 −7 mol L −1 . And, the method was also applied to detect sophoridine in spiked human urine with wonderful satisfactory

  12. A Reagentless Amperometric Formaldehyde-Selective Chemosensor Based on Platinized Gold Electrodes

    OpenAIRE

    Demkiv, Olha; Smutok, Oleh; Gonchar, Mykhailo; Nisnevitch, Marina

    2017-01-01

    Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde analysis based on platinized gold electrodes is described. The platinization process was performed electrochemically on the surface of 4 mm gold planar electrodes by both electrolysis and cyclic voltamperometry. The produced electrodes were characterized using scanning electron microscopy and X-ray spectral analysis. Using a low working potential (0.0 V vs. Ag/AgCl) enabled an essential increase in th...

  13. Electrochemical Sensing toward Trace As(III Based on Mesoporous MnFe2O4/Au Hybrid Nanospheres Modified Glass Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Shaofeng Zhou

    2016-06-01

    Full Text Available Au nanoparticles decorated mesoporous MnFe2O4 nanocrystal clusters (MnFe2O4/Au hybrid nanospheres were used for the electrochemical sensing of As(III by square wave anodic stripping voltammetry (SWASV. Modified on a cheap glass carbon electrode, these MnFe2O4/Au hybrid nanospheres show favorable sensitivity (0.315 μA/ppb and limit of detection (LOD (3.37 ppb toward As(III under the optimized conditions in 0.1 M NaAc-HAc (pH 5.0 by depositing for 150 s at the deposition potential of −0.9 V. No obvious interference from Cd(II and Hg(II was recognized during the detection of As(III. Additionally, the developed electrode displayed good reproducibility, stability, and repeatability, and offered potential practical applicability for electrochemical detection of As(III in real water samples. The present work provides a potential method for the design of new and cheap sensors in the application of electrochemical determination toward trace As(III and other toxic metal ions.

  14. Electrochemical Sensing toward Trace As(III) Based on Mesoporous MnFe₂O₄/Au Hybrid Nanospheres Modified Glass Carbon Electrode.

    Science.gov (United States)

    Zhou, Shaofeng; Han, Xiaojuan; Fan, Honglei; Liu, Yaqing

    2016-06-22

    Au nanoparticles decorated mesoporous MnFe₂O₄ nanocrystal clusters (MnFe₂O₄/Au hybrid nanospheres) were used for the electrochemical sensing of As(III) by square wave anodic stripping voltammetry (SWASV). Modified on a cheap glass carbon electrode, these MnFe₂O₄/Au hybrid nanospheres show favorable sensitivity (0.315 μA/ppb) and limit of detection (LOD) (3.37 ppb) toward As(III) under the optimized conditions in 0.1 M NaAc-HAc (pH 5.0) by depositing for 150 s at the deposition potential of -0.9 V. No obvious interference from Cd(II) and Hg(II) was recognized during the detection of As(III). Additionally, the developed electrode displayed good reproducibility, stability, and repeatability, and offered potential practical applicability for electrochemical detection of As(III) in real water samples. The present work provides a potential method for the design of new and cheap sensors in the application of electrochemical determination toward trace As(III) and other toxic metal ions.

  15. Voltammetric measurement of the Pt electrode capacity and the determination of the polyvalent ions diffusion coefficients in the glass melt

    Czech Academy of Sciences Publication Activity Database

    Vondrák, Jiří; Rohanová, D.; Klápště, Břetislav; Velická, Jana

    2003-01-01

    Roč. 47, č. 2 (2003), s. 51-55 ISSN 0862-5468 R&D Projects: GA AV ČR IAA4032002 Institutional research plan: CEZ:AV0Z4032918; CEZ:MSM 262200010 Keywords : electric capacity of pt electrode * polyvalent ions * Fe3- and Cr3- ions Subject RIV: CA - Inorganic Chemistry Impact factor: 0.449, year: 2003

  16. Phase selection and microstructure in directional solidification of glass forming Pd-Si-Cu alloys

    Science.gov (United States)

    Huo, Yang

    Phase selection and microstructure formation during the rapid solidification of alloy melts has been a topic of substantial interest over the last several decades, attributed mainly to the access to novel structures involving metastable crystalline and non-crystalline phases. In this work, Bridgeman type directional solidification was conducted in Pd-Si-Cu glass forming system to study such cooling rate dependent phase transition and microstructure formation. The equilibrium state for Pd-Si-Cu ternary system was investigated through three different works. First of all, phase stabilities for Pd-Si binary system was accessed with respects of first-principles and experiments, showing Pd5Si, Pd9Si2, Pd3Si and Pd 2Si phase are stable all way to zero Kevin while PdSi phase is a high temperature stable phase, and Pd2Si phase with Fe2P is a non-stoichiometry phase. A thermodynamic database was developed for Pd-Si system. Second, crystal structures for compounds with ternary compositions were studied by XRD, SEM and TEM, showing ordered and disordered B2/bcc phases are stable in Pd-rich part. At last, based on many phase equilibria and phase transitions data, a comprehensive thermodynamic discrption for Pd-Si-Cu ternary system was first time to be developed, from which different phase diagrams and driving force for kinetics can be calculated. Phase selection and microstructure formation in directional solidification of the best glass forming composition, Pd 77.5Si16.5Cu6, in this system with growth velocities from 0.005 to 7.5mm/s was systematically studied and the solidification pathways at different conditions were interpreted from thermodynamic simulation. The results show that for growth velocities are smaller than 0.1mm/s Pd 3Si phase is primary phase and Pd9Si2 phase is secondary phase, the difficulty for Pd9Si2 phase nucleation gives rise to the formation of two different eutectic structure. For growth velocities between 0.4 and 1mm/s, instead of Pd3Si phase, Pd9Si2

  17. Electrode selection for hearing preservation in cochlear implantation: A review of the evidence

    Directory of Open Access Journals (Sweden)

    Jason A. Brant

    2016-09-01

    Full Text Available Objective: To review and assess the ideal length of electrode in cochlear implant patients for hearing preservation. Methods: The English language literature was reviewed for studies including hearing preservation and speech understanding for electrodes of different lengths. Results: One prospective trial was found, and there were no studies that randomized patients into different length electrodes with an intent to preserve hearing. Eight studies total included multiple length electrodes and contained data regarding hearing preservation. Conclusions: Although there is some evidence that indicates that shorter electrodes may improve both short and long-term hearing preservation rates in cochlear implant patients, no study has directly compared implant length on hearing preservation in a similar patient population. A randomized trial of short and standard length electrodes for hearing preservation is warranted. In the interim, utilization of current electrodes measuring 20–25 mm could seem to be a prudent approach when seeking to preserve residual hearing without unduly compromising cochlear coverage. Keywords: Electrode, Length, Hearing preservation, Cochlear implantation

  18. IMPROVED SELECTIVE ELECTROCATALYTIC OXIDATION OF PHENOLS BY TYROSINASE-BASED CARBON PASTE ELECTRODE BIOSENSOR

    Science.gov (United States)

    Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil yielded a greater response to phenol and catechol than those using a higher viscosity oil of s...

  19. Redox cycling with facing interdigitated array electrodes as a method for selective detection of redox species

    NARCIS (Netherlands)

    Dam, T.V.A.; Olthuis, Wouter; van den Berg, Albert

    2007-01-01

    A pair of interdigitated ultramicroelectrodes (UMEs) is used to electrochemically detect a weak reductor ( dopamine) in the presence of a stronger one (K-4[ Fe(CN)(6)]). In the mixture of both reductors, one of the two interdigitated electrodes ( the generator electrode) is used to oxidize both

  20. Redox cycling with facing interdigitated array electrodes as a method for selective detection of redox species

    NARCIS (Netherlands)

    Dam, V.A.T.; Olthuis, W.; Berg, van den A.

    2007-01-01

    A pair of interdigitated ultramicroelectrodes (UMEs) is used to electrochemically detect a weak reductor (dopamine) in the presence of a stronger one (K4[Fe(CN)6]). In the mixture of both reductors, one of the two interdigitated electrodes (the generator electrode) is used to oxidize both species at

  1. Using ion-selective electrode for determining iodine-131 preparation specific activity

    International Nuclear Information System (INIS)

    Melnik, M.I.; Nazirova, T.E.

    2002-01-01

    A pilot facility was developed in 2000 for the production of iodine-131. The parameters of the preparation are as follows: chemical form: sodium iodide solution (NaI-131) in a carbonate-bicarbonate buffer (or in 0.001M NaOH); specific activity: carrier free (> 5 Ci/mg); solution pH: 7-10; radionuclide purity: > 99.9%; radiochemical purity: > 97%; bulk activity: 0.15 Ci/ml. The experimental results of investigation aimed at the determination of the specific activity of the I-131 preparation using a iodine-selective electrode are described. The method enables the analytical concentration of iodide ions in the carbonate-bicarbonate buffer (pH = 8-11) and NaOH solution (0.01 mol/l, pH = 8-11) to be determined. A micro-cell has been developed for the analysis of the I-131 solution allowing the sample volume to be reduced to below 0.3 ml. The relative error of determination of the analytical concentration of iodide (10 -6 to 10 -1 mol/l) does not exceed 1%

  2. Selective electrochemical detection of dopamine in a microfluidic channel on carbon nanoparticulate electrodes.

    Science.gov (United States)

    Rozniecka, Ewa; Jonsson-Niedziolka, Martin; Celebanska, Anna; Niedziolka-Jonsson, Joanna; Opallo, Marcin

    2014-06-07

    There is a continuous need for the construction of detection systems in microfluidic devices. In particular, electrochemical detection allows the separation of signals from the analyte and interfering substances in the potential domain. Here, a simple microfluidic device for the sensitive and selective determination of dopamine in the presence of interfering substances was constructed and tested. It employs a carbon nanoparticulate electrode allowing the separation of voltammetric signals of dopamine and common interfering substances (ascorbic acid and acetaminophen) both in quiescent conditions and in flow due to the electrocatalytic effect. These voltammograms were also successfully simulated. The limit of detection of dopamine detected by square wave voltammetry in 1 mM solutions of interfering substances in phosphate buffered saline is about 100 nM. In human serum a clear voltammetric signal could be seen for a 200 nM solution, sufficient to detect dopamine in the cerebral fluid. Flow injection analysis allows a decrease in the limit of detection down to 3.5 nM.

  3. Improving the Response of Copper(II) Selective PVC Membrane Electrode by Modification of N2S2 Donor Ligand.

    Science.gov (United States)

    Brinić, Slobodan; Buzuk, Marijo; Generalić, Eni; Bralić, Marija

    2010-06-01

    S,S'-bis(2-aminophenyl)ethanebis(thioate), (APhET), is reported as N2S2 ligand which form chelate with copper of high stability as compared to the other metals. Two modification of APhET, simpler 1,2-di-(o-aminophenylthio)ethane (DAPhTE), and the complex one 1,2-di-(o-salicylaldiminophenylthio)ethane (SAPhTE), were examined as the active material for copper(II) ion selective PVC membrane electrodes, and observed results are correlated. The obtained results with DAPhTE based electrodes show that only coordination abilities of ligand are insufficient for preparing the efficient membrane material. On the other hand, the results that are achieved with electrodes based on SAPhTE actuate interaction of ligand with polymer membrane matrix and necessity of ionophore immobilization in membrane. Optimized SAPhTE based membrane electrode has a linear range down to 10-6 mol L-1, with slope of 27.0 mV per decade, very rapid response time (under 5 seconds) and detection limit of 5.1 × 10-7 mol L-1. Such electrode is suitable for determination of copper(II) in analytical measurements by direct potentiometry and in potentiometric titrations, within pH between 2 and 7. The electrode is selective for copper(II) ions over a large number of metal ions, with the exception on Hg2+ ion when is present in concentrations above 2 × 10-5 mol L-1.

  4. Eletrodo íon-seletivo para determinação potenciométrica de alumínio(III em meio de fluoreto Ion-selective electrode for potentiometric determination of aluminium(III in fluoride medium

    Directory of Open Access Journals (Sweden)

    Evandro Piccin

    2004-12-01

    Full Text Available The construction and analytical evaluation of a coated graphite Al(III ion-selective electrode, based on the ionic pair formed between the Al(Fn3-n anion and tricaprylylmethylammonium cation (Aliquat 336S incorporated on a poly(vinylchloride (PVC matrix membrane are described. A thin membrane film of this ionic pair and dibutylphthalate (DBPh in PVC was deposited directly on a cylindric graphite rod (2 cm length x 0.5 cm diameter attached to the end of a glass tube using epoxy resin. The membrane solution was prepared by dissolving 40% (m/m of PVC in 10 mL of tetrahydrofuran following addition of 45% (m/m of DBPh and 15% (m/m of the ionic pair. The effect of membrane composition, fluoride concentration, and several concomitants as potential interferences on the electrode response were investigated. The aluminium(III ion-selective electrode showed a linear response ranging from 1.4 x 10-4 to 1.0 x 10-2 mol L-1, a detection limit of 4.0 x 10-5 mol L-1, aslope of -54.3±0.2mV dec-1 and a lifetime of more than 1 year (over 3000 determinations for each membrane. The slope indicates that the ion-selective electrode responds preferentially to the Al(F4- species. Application of this electrode for the aluminium(III determination in stomach anti-acid samples is reported.

  5. Liquidus temperature and chemical durability of selected glasses to immobilize rare earth oxides waste

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Fadzil, Syazwani, E-mail: mfsyazwani86@postech.ac.kr [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, 790784 Pohang, Gyeongbuk (Korea, Republic of); School of Applied Physics, Faculty of Science and Technology, The National University of Malaysia, 43650 Bandar Baru Bangi, Selangor (Malaysia); Hrma, Pavel [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, 790784 Pohang, Gyeongbuk (Korea, Republic of); Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA (United States); Schweiger, Michael J.; Riley, Brian J. [Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA (United States)

    2015-10-15

    Pyroprocessing is are processing method for managing and reusing used nuclear fuel (UNF) by dissolving it in an electrorefiner with a molten alkali or alkaline earth chloride salt mixture while avoiding wet reprocessing. Pyroprocessing UNF with a LiCl–KCl eutectic salt releases the fission products from the fuel and generates a variety of metallic and salt-based species, including rare earth (RE) chlorides. If the RE-chlorides are converted to oxides, borosilicate glass is a prime candidate for their immobilization because of its durability and ability to dissolve almost any RE waste component into the glass matrix at high loadings. Crystallization that occurs in waste glasses as the waste loading increases may complicate glass processing and affect the product quality. This work compares three types of borosilicate glasses in terms of liquidus temperature (T{sub L}): the International Simple Glass designed by the International Working Group, sodium borosilicate glass developed by Korea Hydro and Nuclear Power, and the lanthanide aluminoborosilicate (LABS) glass established in the United States. The LABS glass allows the highest waste loadings (over 50 mass% RE{sub 2}O{sub 3}) while possessing an acceptable chemical durability. - Highlights: • We investigated crystallization in borosilicate glasses containing rare earth oxides. • New crystallinity and durability data are shown for glasses proposed in the literature. • Both liquidus temperature and chemical durability increased as the waste loading increased.

  6. Comparative Study of PVC-Free All-Solid-State, PVC Membrane, and Carbon Paste Ion-Selective Electrodes for the Determination of Dapoxetine Hydrochloride in Pharmaceutical Formulation.

    Science.gov (United States)

    Aziz, Azza; Khamees, Nesrin; Mohamed, Tagreed Abdel-Fattah; Derar, Abeer Rashad

    2016-11-01

    The potentiometric response characteristics and analytical applications of a poly(vinyl chloride) (PVC)-free all-solid-state ion-selective electrode for dapoxetine hydrochloride (DAP) are examined. The Nernstian response of the electrode was evaluated by comparison with PVC-based liquid membrane and carbon paste electrodes. The PVC-free electrode is prepared by direct incorporation of dapoxetine-tetraphenyl borate (DAP-TPB) as a sensing element into a commercial nail varnish containing cellulose acetate propionate. The composite was applied onto a 3 mm diameter graphite disk electrode. The electrode exhibited a Nernstian slope of 56.0 mV/decade in the concentration range of 1 × 10-4 to 1 × 10-2 mol/L with an LOD of 2 × 10-5 mol/L. The electrode is independent of pH in the range of 2 to 6 and showed good selectivity for DAP with respect to a large number of inorganic cations and amino acids. Comparable Nernstian slope, sensitivity, pH range, and selectivity pattern were obtained with a PVC membrane and a carbon paste incorporating DAP-TPB as a sensing element and dioctylphthalate as a solvent mediator. The electrodes were used for the determination of DAP in pure solution and in tablets without extraction with high accuracy and precision (RSD ≤ 2%). The nail varnish solid-state electrode is simple, economical, and rapid when compared with PVC membrane and carbon paste electrodes.

  7. Electrodes for 24 hours pH monitoring--a comparative study.

    OpenAIRE

    McLauchlan, G; Rawlings, J M; Lucas, M L; McCloy, R F; Crean, G P; McColl, K E

    1987-01-01

    Three pH electrodes in clinical use were examined--(1) antimony electrode with remote reference electrode (Synectics 0011), (2) glass electrode with remote reference electrode (Microelectrodes Inc. MI 506) and (3) combined glass electrode with integral reference electrode (Radiometer GK2801C). In vitro studies showed that both glass electrodes were similar and superior to the antimony electrode with respect to response time, drift, and sensitivity. The effect of the siting of the reference el...

  8. An amperometric uric acid biosensor based on Bis[sulfosuccinimidyl] suberate crosslinker/3-aminopropyltriethoxysilane surface modified ITO glass electrode

    International Nuclear Information System (INIS)

    Ahuja, Tarushee; Rajesh; Kumar, Devendra; Tanwar, Vinod Kumar; Sharma, Vikash; Singh, Nahar; Biradar, Ashok M.

    2010-01-01

    A label free, amperometric uric acid biosensor is described by immobilizing enzyme uricase through a self assembled monolayer (SAM) of 3-aminopropyltriethoxysilane (APTES) using a crosslinker, Bis[sulfosuccinimidyl]suberate (BS 3 ) on an indium-tin-oxide (ITO) coated glass plate. The biosensor (uricase/BS 3 /APTES/ITO) was characterized by, scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrochemical techniques. Chronoamperometric response was measured as a function of uric acid concentration in aqueous solution (pH 7.4). The biosensor shows a linear response over a concentration range of 0.05 to 0.58 mM with a sensitivity of 39.35 μA mM -1 . The response time is 50 s reaching to a 95% steady state current value and about 90% of enzyme activity is retained for about 7 weeks. These results indicate an efficient binding of enzyme with the crosslinker over the surface of APTES modified ITO glass plates, which leads to an improved sensitivity and shelf life of the biosensor.

  9. Charge-carrier selective electrodes for organic bulk heterojunction solar cell by contact-printed siloxane oligomers

    International Nuclear Information System (INIS)

    Hwang, Hyun-Sik; Khang, Dahl-Young

    2015-01-01

    ‘Smart’ (or selective) electrode for charge carriers, both electrons and holes, in organic bulk-heterojunction (BHJ) solar cells using insertion layers made of hydrophobically-recovered and contact-printed siloxane oligomers between electrodes and active material has been demonstrated. The siloxane oligomer insertion layer has been formed at a given interface simply by conformally-contacting a cured slab of polydimethylsiloxane stamp for less than 100 s. All the devices, either siloxane oligomer printed at one interface only or printed at both interfaces, showed efficiency enhancement when compared to non-printed ones. The possible mechanism that is responsible for the observed efficiency enhancement has been discussed based on the point of optimum symmetry and photocurrent analysis. Besides its simplicity and large-area applicability, the demonstrated contact-printing technique does not involve any vacuum or wet processing steps and thus can be very useful for the roll-based, continuous production scheme for organic BHJ solar cells. - Highlights: • Carrier-selective insertion layer in organic bulk heterojunction solar cells • Simple contact-printing of siloxane oligomers improves cell efficiency. • Printed siloxane layer reduces carrier recombination at electrode surfaces. • Siloxane insertion layer works equally well at both electrode surfaces. • Patterned PDMS stamp shortens the printing time within 100 s

  10. Sensitive and selective determination of Cu2+ at D-penicillamine functionalized nano-cellulose modified pencil graphite electrode

    Science.gov (United States)

    Taheri, M.; Ahour, F.; Keshipour, S.

    2018-06-01

    A novel electrochemical sensor based on D-penicillamine anchored nano-cellulose (DPA-NC) modified pencil graphite electrode was fabricated and used for highly selective and sensitive determination of copper (II) ions in the picomolar concentration by square wave adsorptive stripping voltammetric (SWV) method. The modified electrode showed better and increased SWV response compared to the bare and NC modified electrodes which may be related to the porous structure of modifier along with formation of complex between Cu2+ ions and nitrogen or oxygen containing groups in DPA-NC. Optimization of various experimental parameters influence the performance of the sensor, were investigated. Under optimized condition, DPA-NC modified electrode was used for the analysis of Cu2+ in the concentration range from 0.2 to 50 pM, and a lower detection limit of 0.048 pM with good stability, repeatability, and selectivity. Finally, the practical applicability of DPA-NC-PGE was confirmed via measuring trace amount of Cu (II) in tap and river water samples.

  11. Fabrication of copper-selective PVC membrane electrode based on newly synthesized copper complex of Schiff base as carrier

    Directory of Open Access Journals (Sweden)

    Sulekh Chandra

    2016-09-01

    Full Text Available The newly synthesized copper(II complex of Schiff base p-hydroxyacetophenone semicarbazone was explored as neutral ionophore for the fabrication of poly(vinylchloride (PVC based membrane electrode selective to Cu(II ions. The electrode shows a Nernstian slope of 29.8 ± 0.3 mV/decade with improved linear range of 1.8 × 10−7 to 1.0 × 10−1 M, comparatively lower detection limit 5.7 × 10−8 M between pH range of 2.0–8.0, giving a relatively fast response within 5s and can be used for at least 16 weeks without any divergence in potential. The selectivity coefficient was calculated using the fixed interference method (FIM. The electrode can also be used in partially non-aqueous media having up to 25% (v/v methanol, ethanol or acetone content with no significant change in the value of slope or working concentration range. It was successfully applied for the direct determination of copper content in water and tea samples with satisfactory results. The electrode has been used in the potentiometric titration of Cu2+ with EDTA.

  12. Yttrium-90 Selective Internal Radiation Therapy with Glass Microspheres for Hepatocellular Carcinoma: Current and Updated Literature Review

    International Nuclear Information System (INIS)

    Lee, Edward Wolfgang; Alanis, Lourdes; Cho, Sung-Ki; Saab, Sammy

    2016-01-01

    Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma

  13. Yttrium-90 selective internal radiation therapy with glass microspheres for hepatocellular carcinoma: Current and updated literature review

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Edward Wolfgang; Alanic, Lourdes [Div. of Interventional Radiology, Dept. of Radiology, UCLA Medical Center, David Geffen School of Medicine at UCLA, Los Angeles (United States); Cho, Sung Ki [Div. of Interventional Radiology, Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Saab, Sammy [Div. of Hepatology, Dept. of Medicine, Pfleger Liver Institute, University of California at Los Angeles, Los Angeles (United States)

    2016-07-15

    Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma.

  14. Yttrium-90 Selective Internal Radiation Therapy with Glass Microspheres for Hepatocellular Carcinoma: Current and Updated Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Edward Wolfgang; Alanis, Lourdes [Division of Interventional Radiology, Department of Radiology, UCLA Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Cho, Sung-Ki [Division of Interventional Radiology, Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351 (Korea, Republic of); Saab, Sammy [Division of Hepatology, Department of Medicine, Pfleger Liver Institute, University of California at Los Angeles, Los Angeles, CA 90024 (United States)

    2016-11-01

    Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma.

  15. Yttrium-90 selective internal radiation therapy with glass microspheres for hepatocellular carcinoma: Current and updated literature review

    International Nuclear Information System (INIS)

    Lee, Edward Wolfgang; Alanic, Lourdes; Cho, Sung Ki; Saab, Sammy

    2016-01-01

    Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma

  16. A Decision Support Concept for a construction design project – selecting the type of glass façade

    Directory of Open Access Journals (Sweden)

    Franjo Šimić

    2017-01-01

    Full Text Available The paper describes research into the possibility of developing a concept for supporting decisions in planning construction projects (one of the most important stages of construction project management. The focus is on supporting decisions in selecting the type of and solution for the glass façade in the main design. Materials and types of soluteons for a glass façade were analyzed and alternative solutions were obtained. The concept was developed in that it included relevant stakeholders in the decision-making process during the construction design. These stakeholders were the investor, architect, and construction contractor. The analysis was carried out and a hierarchical structure of objectives was formed as a goal tree. The criteria at the last hierarchical level were used to evaluate alternative solutions for the glass façade, and their weights were determined by all stakeholders using the AHP method (Analytic Hierarchy Process. Using PROMETHEE (Preference Ranking Method for Enrichment Evaluation, a comparison of alternative solutions for the glass façade was conducted and the alternatives were ranked according to the priorities for inclusion into the main design. The concept was tested by selecting a type of glass façade on a residential-commercial building in the city of Rijeka, Croatia.

  17. Yttrium-90 Selective Internal Radiation Therapy with Glass Microspheres for Hepatocellular Carcinoma: Current and Updated Literature Review.

    Science.gov (United States)

    Lee, Edward Wolfgang; Alanis, Lourdes; Cho, Sung-Ki; Saab, Sammy

    2016-01-01

    Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma.

  18. Hemi-ordered nanoporous carbon electrode material for highly selective determination of nitrite in physiological and environmental systems

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shenghai; Wu, Hongmin; Wu, Ying; Shi, Hongyan; Feng, Xun; Jiang, Shang; Chen, Jian; Song, Wenbo, E-mail: wbsong@jlu.edu.cn

    2014-08-01

    Hemi-ordered nanoporous carbon (HONC) was obtained from a mesoporous silica template through a nano-replication method using furfuryl alcohol as the carbon source. The structure and morphology of HONC were characterized and analyzed in detail by X-ray diffraction, N{sub 2}-sorption, Raman spectroscopy and transmission electron microscopy. HONC was then demonstrated as active electrode material for selective determination of nitrite in either physiological or environmental system. Well separated oxidation peaks of ascorbic acid, dopamine, uric acid and nitrite were observed in physiological system, and simultaneous discrimination of catechol, hydroquinone, resorcinol and nitrite in environmental system was also accomplished. Distinctly improved performances for selective determination of nitrite (such as significantly fast and sensitive current response with especially high selectivity) coexisted with ascorbic acid, dopamine and uric acid in the physiological system, as well as with catechol, hydroquinone and resorcinol in the environmental system were achieved at HONC electrode material. The excellent discriminating ability and high selectivity for NO{sub 2}{sup −} determination were ascribed to the good electronic conductivity, unique hemi-ordered porous structure, large surface area and large number of edge plane defect sites contained on the surface of nanopore walls of HONC. Results in this work demonstrated that HONC is one of the promising catalytic electrode materials for nitrite sensor fabrication. - Highlights: • Hemi-ordered nanoporous carbon as an active electrode material • Good discriminating ability towards NO{sub 2}{sup −} from physiological or environmental system • Highly selective determination of nitrite with fast and sensitive current response.

  19. Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

    International Nuclear Information System (INIS)

    Gupta, V.K.; Singh, A.K.; Gupta, Barkha

    2007-01-01

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S 1 ) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S 2 ) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S 1 ) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10 -8 to 1.0 x 10 -1 M Cd 2+ with limit of detection 5.0 x 10 -8 M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants

  20. Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, V.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)]. E-mail: vinodfcy@iitr.ernet.in; Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India); Gupta, Barkha [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

    2007-02-05

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S{sub 1}) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S{sub 2}) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S{sub 1}) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10{sup -8} to 1.0 x 10{sup -1} M Cd{sup 2+} with limit of detection 5.0 x 10{sup -8} M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

  1. Quantitative Determination of NTA and Other Chelating Agents in Detergents by Potentiometric Titration with Copper Ion Selective Electrode.

    Science.gov (United States)

    Ito, Sana; Morita, Masaki

    2016-01-01

    Quantitative analysis of nitrilotriacetate (NTA) in detergents by titration with Cu 2+ solution using a copper ion selective electrode was achieved. This method tolerates a wide range of pH and ingredients in detergents. In addition to NTA, other chelating agents, having relatively lower stability constants toward Cu 2+ , were also qualified with sufficient accuracy by this analytical method for model detergent formulations. The titration process was automated by automatic titrating systems available commercially.

  2. Study of the spheronization process of glass particles by the gravitational falling process for internal selective radiotherapy

    International Nuclear Information System (INIS)

    Barros Filho, E.C.; Martinelli, J.R.; Sene, F.F.

    2011-01-01

    The internal selective radiotherapy is an alternative to treat hepatocellular carcinoma. Glass microspheres containing β - emitter radionuclide are introduced in the liver, and they are housed preferentially in the region where the cancer cells are located. The microspheres are trapped in the arterioles which feed the tumors, and the β - particles annihilate the cancer cells. The glass particles must be spherical to avoid unnecessary bleeding, and the particle size must be restricted to a range which optimizes the blocking effect and avoid the migration to other parts of the human body. The particle size distribution of microspheres is not easily predicted since the variation of the aspect ratio and the presence of agglomerates can influence the resulting particle size distribution. In the present work, the spheronization process to obtain microspheres from irregular shape glass particles with suitable diameter and shape for radiotherapy treatment is studied. (author)

  3. Stability and selectivity of a chronic, multi-contact cuff electrode for sensory stimulation in human amputees.

    Science.gov (United States)

    Tan, Daniel W; Schiefer, Matthew A; Keith, Michael W; Anderson, J Robert; Tyler, Dustin J

    2015-04-01

    Stability and selectivity are important when restoring long-term, functional sensory feedback in individuals with limb-loss. Our objective is to demonstrate a chronic, clinical neural stimulation system for providing selective sensory response in two upper-limb amputees. Multi-contact cuff electrodes were implanted in the median, ulnar, and radial nerves of the upper-limb. Nerve stimulation produced a selective sensory response on 19 of 20 contacts and 16 of 16 contacts in subjects 1 and 2, respectively. Stimulation elicited multiple, distinct percept areas on the phantom and residual limb. Consistent threshold, impedance, and percept areas have demonstrated that the neural interface is stable for the duration of this on-going, chronic study. We have achieved selective nerve response from multi-contact cuff electrodes by demonstrating characteristic percept areas and thresholds for each contact. Selective sensory response remains consistent in two upper-limb amputees for 1 and 2 years, the longest multi-contact sensory feedback system to date. Our approach demonstrates selectivity and stability can be achieved through an extraneural interface, which can provide sensory feedback to amputees.

  4. Evaluation of the Seismic Characterision of Select Engineered Nanoparticles in Saturated Glass Beads

    Science.gov (United States)

    A laboratory testing apparatus was developed for the study of seismic body wave propagation through nanoparticles dispersed in pore fluid that is essentially saturating glass beads. First, the responses of water-saturated glass bead specimens were studied to establish baseline si...

  5. ELECTRODE SELECTION FOR RECOVERY OF THE CYLINDER LIDS OF THE TGM8K LOCOMITIVE ENGINE

    Directory of Open Access Journals (Sweden)

    Pablo Oñoz Gutiérrez

    2017-01-01

    Full Text Available The objective of this work was to determine the best-suited electrode to carry out the recovery of cylinder lids (cylinders heads of the TGM8K locomotives, by applying manual welding for electric arc. The test specimens of nodular cast iron, obtained from a discarded head, which were welded with two types electrodes, ENi-CI (UTP8 and ENiFe-CI ( UTP86FN following a technology of appropriate welding were prepared. The specimens were subject of thermic fatigue tests in an experimental installation created with this purpose, in which a process of heating and more severe cooling than in the head working conditions was simulated. During the thermic fatigue tests, in the specimens welded with electrodes ENi-CI appeared cracks at the thermic influence zone after 145 cycles, while in the specimens welded with electrodes ENiFe-CI, appeared at the 585 cycles on average. Based on the study results, the authors conclude that ENiFe-CI electrodes are the best-suited for the recovery of the cylinder lids.

  6. Wavelength-selective bleaching of the optical spectra of trapped electrons in organic glasses. II

    International Nuclear Information System (INIS)

    Paraszczak, J.; Willard, J.E.

    1979-01-01

    Further resolution of the inhomogeneous optical spectra of trapped electrons (e - /sub t/) in organic glasses has been obtained from wavelength selective bleaching and thermal decay studies on 3-methylpentane-d 14 (3MP-d 14 ) and 2-methyltetrahydrofuran (MTHF) following γ irradiation in the temperature region of 20 K, and limits on the degree of resolution achievable have been indicated. Exposure of 3MP-d 14 to light of wavelengths >2100 nm (from a tunable laser) reduces the optical densities at the bleaching wavelength and longer to zero, while ''peeling off'' a portion of the O.D. at all shorter wavelengths but leaving the remainder of the spectrum unaffected. The fraction of the integrated optical spectrum, ∫OD d (eV), removed by bleaching at each wavelength tested, and also by thermal decay, is equivalent to the fraction of the total e - /sub t/ spins removed and measured by ESR. 1064 nm light bleaches the spectrum nearly uniformly, confirming that the spectra of all of the e - /sub t/ have blue tails with similar ease of bleaching. Heretofore unobserved low temperature thermal decay of e - /sub t/ occurs at 20 and 40 K (20% of the spin concentration in 30 min, 35% in 3h). The rate of decay of the optical spectrum decreases with decreasing wavelength of observation (2.5, 2.2, 1.8, and 1.5 μ), but at each wavelength is the same at 40 K as at 20 K, consistent

  7. Concerted Electrodeposition and Alloying of Antimony on Indium Electrodes for Selective Formation of Crystalline Indium Antimonide.

    Science.gov (United States)

    Fahrenkrug, Eli; Rafson, Jessica; Lancaster, Mitchell; Maldonado, Stephen

    2017-09-19

    The direct preparation of crystalline indium antimonide (InSb) by the electrodeposition of antimony (Sb) onto indium (In) working electrodes has been demonstrated. When Sb is electrodeposited from dilute aqueous electrolytes containing dissolved Sb 2 O 3 , an alloying reaction is possible between Sb and In if any surface oxide films are first thoroughly removed from the electrode. The presented Raman spectra detail the interplay between the formation of crystalline InSb and the accumulation of Sb as either amorphous or crystalline aggregates on the electrode surface as a function of time, temperature, potential, and electrolyte composition. Electron and optical microscopies confirm that under a range of conditions, the preparation of a uniform and phase-pure InSb film is possible. The cumulative results highlight this methodology as a simple yet potent strategy for the synthesis of intermetallic compounds of interest.

  8. Development of a sensitive and selective Riboflavin sensor based on carbon ionic liquid electrode

    International Nuclear Information System (INIS)

    Safavi, Afsaneh; Maleki, Norouz; Ershadifar, Hamid; Tajabadi, Fariba

    2010-01-01

    The electrochemical properties of Riboflavin adsorbed on carbon ionic liquid electrode (CILE) were studied by cyclic voltammetry. A film with a surface coverage of up to 3.3 x 10 -9 mol cm -2 was formed after 10 min exposure time. Electron transfer coefficient and rate constant of electron transfer across the modified electrode were found to be 0.43 and 3.03 s -1 , respectively. Differential pulse voltammetry was used for the determination of Riboflavin. Two linear working ranges of 0.8-110 nM and 0.11-1.0 μM were obtained with correlation coefficients of 0.998 and 0.996, respectively. The experimental detection limit was obtained as 0.1 nM. The relative standard deviation for five replicate analyses was 4.7%. Other soluble vitamins had no significant interferences and the electrode was used for the determination of Riboflavin in pharmaceutical products, nutrition and beverages.

  9. Development of a reagentless electrochemiluminescent electrode for flow injection analysis using copolymerised luminol/aniline on nano-TiO2 functionalised indium-tin oxide glass.

    Science.gov (United States)

    Liu, Chao; Wei, Xiuhua; Tu, Yifeng

    2013-07-15

    In this study, a nano-structured copolymer of luminol/aniline (PLA) was deposited onto nano-TiO2-functionalised indium tin oxide (ITO)-coated glass by electrochemical polymerisation using cyclic voltammetry (CV). The resulting reagentless electrochemiluminescent (ECL) electrode (ECLode) can be used for flow injection analysis (FIA). The properties of the ECLode were characterised by CV, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The ECLode has high background ECL emission as well as excellent stability and reproducibility, and yielding sensitive response towards target analytes. The ECL emissions of the ECLode were 50 times higher than PLA/ITO, and 500 times higher than polyluminol (PL)/ITO. The ECLode showed sensitive responses to reactive oxygen species (ROSs), permitting its application for determination of antioxidants by quenching. Under optimised conditions, an absolute detection limit of 69.9 pg was obtained for resveratrol, comparable to the highest levels of sensitivity achieved by other methods. Thus, the gross antioxidant content of red wine was determined, with satisfactory recoveries between 87.6% and 108.3%. These results suggest a bright future for the use of the ECLode for single-channel FIA due to its high sensitivity, accuracy and reproducibility. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Use of ion selective electrodes for potentiometric analysis of solutions containing cadmium and cyanide ions

    International Nuclear Information System (INIS)

    Aleksandrov, V.V.; Glazkova, E.N.; Izmajlova, G.A.

    1988-01-01

    Technique for cadmium potentiometric determination in the cadmium-plating cyanide electrolyte, which countains Cd(CN) n 2-n (n=1,2,3,4) complexes, is developed. Reactions of cadmium precipitation in the form of diethyldithiocarbamate serve as the ground for determination technique. Polycrystalline membrane electrodes with hard contact are used as indicator electrodes. Pd, Ni, Cu, Ag do not interfere with cadmium determination, Fe, Zn, Bi may coprecipitate with cadmium. Determination limit of cadmium ions is 5x10 -3 M

  11. All-Solid-State, PVC Membrane, and Carbon Paste Ion-Selective Electrodes for Determination of Donepezil Hydrochloride in Pharmaceutical Formulation.

    Science.gov (United States)

    Khamees, Nesreen; Mohamed, Tagreed Abdel-Fattah; Derar, Abeer Rashad; Aziz, Azza

    2017-09-01

    All-solid-state, polyvinyl chloride (PVC) membrane, and carbon paste potentiometric ion-selective electrodes (ISEs) were proposed for the determination of donepezil hydrochloride (DON) in the drug substance and a pharmaceutical formulation. The potentiometric response toward DON was based on the existence of donepezil-tetraphenyl borate (DON-TPB) in a PVC membrane or a carbon paste in the presence of dioctylphthalate. In contrast, the solid-state electrode was prepared by direct incorporation of DON-TPB into a commercial nail varnish without external additives. The electrodes exhibited Nernstian slopes of 55.0, 57.0, and 53.0 mV/decade over the concentration ranges of 1 × 10-5 to 1 × 10-3, 1 × 10-4 to 10-2, and 1 × 10-4 to 5 × 10-3 for the solid-state, PVC membrane, and carbon paste electrodes, respectively. The response of the electrodes is independent of pH in the range of 2-≤8. The electrodes showed good selectivity for DON with respect to a number of inorganic cations and amino acids. The electrodes were used for the determination of DON in pure solution and in pharmaceutical tablets with high accuracy (±2%) and precision (RSD ≤2%). The solid-state electrode is simple, economical, and rapid when compared to the PVC membrane and carbon paste electrodes.

  12. Fabrication of GaAs nanowire devices with self-aligning W-gate electrodes using selective-area MOVPE

    International Nuclear Information System (INIS)

    Ooike, N.; Motohisa, J.; Fukui, T.

    2004-01-01

    We propose and demonstrate a novel self-aligning process for fabricating the tungsten (W) gate electrode of GaAs nanowire FETs by using selective-area metalorganic vapor phase epitaxy (SA-MOVPE) where SiO 2 /W composite films are used to mask the substrates. First, to study the growth process and its dependence on mask materials, GaAs wire structures were grown on masked substrates partially covered with a single W layer or SiO 2 /W composite films. We found that lateral growth over the masked regions could be suppressed when a wire along the [110] direction and a SiO 2 /W composite mask were used. Using this composite mask, we fabricated GaAs narrow channel FETs using W as a Schottky gate electrode, and we were able to observe FET characteristics at room temperature

  13. Criteria for selecting electrodes for electrical stimulation: theoretical and practical considerations.

    Science.gov (United States)

    Brummer, S B; Robblee, L S; Hambrecht, F T

    1983-01-01

    Smaller, more charge-intensive electrodes are needed for "safe" stimulation of the nervous system. In this paper we review critical concepts and the state of the art in electrodes. Control of charge density and charge balance are essential to avoid tissue electrolysis. Chemical criteria for "safe" stimulation are reviewed ("safe" is equated with "chemically reversible"). An example of a safe, but generally impractical, charge-injection process is double-layer charging. The limit here is the onset of irreversible faradaic processes. More charge can be safely injected with so-called "capacitor" electrodes, such as porous intermixtures of Ta/Ta2O5. BaTiO3 has excellent dielectric properties and may provide a new generation of capacitor electrodes. Faradaic charge injection is usually partially irreversible since some of the products escape into the solution. With Pt, up to 400 muc/cm2 real area can be absorbed by faradaic reactions of surface-adsorbed species, but a small part is lost due to metal dissolution. The surface of "activated" Ir is covered with a multilayer hydrated oxide. Charge injection occurs via rapid valence change within this oxide. Little or no metal dissolution is observed, and gassing limits are not exceeded even under stringent conditions.

  14. Tetracaine – selective electrodes with polymer membranes and their application in pharmaceutical formulation control

    Directory of Open Access Journals (Sweden)

    Ahmed Khudhair Hassan

    2017-02-01

    Full Text Available The construction and electrochemical response characteristics of poly(vinyl chloride (PVC membrane electrodes for tetracaine hydrochloride (TCH are described. The sensing membranes incorporating ion-association complexes of tetracaine cation with phosphotungstic acid (PTA or phosphomolybdic acid (PMA or Sodium tetraphenyl borate (NaTPB as electroactive materials and di-n-butyl phthalate (DBPH or tri-n-butyl phosphate (TBP as a plasticizer in PVC matrixes were evaluated. The results obtained show the electrodes based on PTA or PMA as electroactive compounds and DBPH as plasticizer with a fast, stable and near-Nernstian response over a wide concentration range (1 × 10−5–5 × 10−2 M, with cationic slopes of 55.02 and 52.05 mV decade−1 over a pH range of (2.5–6.5. The electrodes show good discrimination of tetracaine from several inorganic cations and sugars. The electrodes were successfully applied for the determination of tetracaine in pharmaceutical formulations.

  15. Mixed ion-exchanger chemically modified carbon paste ion-selective electrodes for determination of triprolidine hydrochloride

    Directory of Open Access Journals (Sweden)

    Yousry M. Issa

    2010-01-01

    Full Text Available Triprolidine hydrochloride (TpCl ion-selective carbon paste electrodes were constructed using Tp-TPB/Tp-CoN and Tp-TPB/Tp-PTA as ion-exchangers. The two electrodes revealed Nernstian responses with slopes of 58.4 and 58.1 mV decade−1 at 25 °C in the ranges 6 × 10−6–1 × 10−2 and 2 × 10−5–1 × 10−2 M for Tp-TPB/Tp-CoN and Tp-TPB/Tp-PTA, respectively. The potentials of these electrodes were independent of pH in the ranges of 2.5–7.0 and 4.5–7.0, and detection limits were 6 × 10−6 and 1 × 10−5 M for Tp-TPB/Tp-CoN and Tp-TPB/Tp-PTA, respectively. The electrodes showed a very good selectivity for TpCl with respect to a large number of inorganic cations and compounds. The standard addition, potentiometric titration methods and FIA were applied to the determination of TpCl in pure solutions and pharmaceutical preparations. The results obtained were in close agreement with those found by the official method. The mean recovery values were 100.91% and 97.92% with low coefficient of variation values of 0.94%, and 0.56% in pure solutions, 99.82% and 98.53% with coefficient of variation values of 2.20%, and 0.73% for Actifed tablet and Actifed syrup, respectively, using the Tp-TPB/Tp-CoN electrode, and 98.85%, and 99.18% with coefficient of variation values of 0.48% and 0.85% for Actifed tablet and Actifed syrup, respectively, using the Tp-TPB/Tp-PTA electrode.

  16. The behaviour of selected yttrium containing bioactive glass microspheres in simulated body environments.

    Science.gov (United States)

    Cacaina, D; Ylänen, H; Simon, S; Hupa, M

    2008-03-01

    The study aims at the manufacture and investigation of biodegradable glass microspheres incorporated with yttrium potentially useful for radionuclide therapy of cancer. The glass microspheres in the SiO2-Na2O-P2O5-CaO-K2O-MgO system containing yttrium were prepared by conventional melting and flame spheroidization. The behaviour of the yttrium silicate glass microspheres was investigated under in vitro conditions using simulated body fluid (SBF) and Tris buffer solution (TBS), for different periods of time, according to half-life time of the Y-90. The local structure of the glasses and the effect of yttrium on the biodegradability process were evaluated by Fourier Transform Infrared (FT-IR) spectroscopy and Back Scattered Electron Imaging of Scanning Electron Microscopy (BEI-SEM) equipped with Energy Dispersive X-ray (EDX) analysis. UV-VIS spectrometry and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for analyzing the release behaviour of silica and yttrium in the two used solutions. The results indicate that the addition of yttrium to a bioactive glass increases its structural stability which therefore, induced a different behaviour of the glasses in simulated body environments.

  17. Selection of a glass-ceramic formulation to immobilize fluorinel- sodium calcine

    International Nuclear Information System (INIS)

    Staples, B.A.; Wood, H.C.

    1994-12-01

    One option for immobilizing calcined high level wastes produced by nuclear fuel reprocessing activities at the Idaho Chemical Processing Plant (ICPP) is conversion to a glass-ceramic form through hot isostatic pressing. Calcines exist in several different chemical compositions, and thus candidate formulations have been developed for converting each to glass-ceramic forms which are potentially resistant to aqueous corrosion and stable enough to qualify for repository storage. Fluorinel/Na, a chemically complex calcine type, is one of the types being stored at ICPP, and development efforts have identified three formulations with potential for immobilizing it. These are a glass forming additive that uses aluminum metal to enhance reactivity, a second glass forming additive that uses titanium metal to enhance reactivity and a third that uses not only a combination of silicon and titanium metals but enough phosphorous pentoxide to form a calcium phosphate host phase in the glass-ceramic product. Glass-ceramics of each formulation performed well in restricted characterization tests. However, none of the three was subjected to rigorous testing that would provide information on whether each was processable, that is able to retain favorable characteristics over a practical range of processing conditions

  18. Physical properties and chemical durability of selected zirconia containing silicate glasses

    Directory of Open Access Journals (Sweden)

    ELEONÓRA GAŠPÁREKOVÁ

    2011-12-01

    Full Text Available Density, thermal expansion, glass transition temperature, refractive index, molar refractivity and chemical durability of five- and six-component glasses with as weighted composition xNa2O·(15-xK2O·yCaO∙(10-yZnO∙zZrO2∙(75-zSiO2 (x = 0, 7.5, 15; y = 0, 5, 10; z = 5, 7 were measured. The obtained experimental data were merged together with the previous results obtained for analogous glasses with lower zirconia content. The full set of glasses enabled the quantitative statistical estimation of possible mixed-oxide effects. The results of the multilinear regression analysis pointed out the ideal behavior of molar volume and molar refractivity. The strongest influence of mutual oxide interactions was found for chemical durability and glass transition temperature. The regression analysis of compositional dependence of metastable melt thermal expansion coefficient practically failed. The need of property-composition study based on the thermodynamic model was pointed out. Qualitatively the obtained results confirmed those previously obtained for the analogous glasses with zirconia content reaching up to 3 mol. %.

  19. Review of progresses on clinical applications of ion selective electrodes for electrolytic ion tests: from conventional ISEs to graphene-based ISEs

    Directory of Open Access Journals (Sweden)

    Rongguo Yan

    2016-10-01

    Full Text Available There exist several positively and negatively charged electrolytes or ions in human blood, urine, and other body fluids. Tests that measure the concentration of these ions in clinics are performed using a more affordable, portable, and disposable potentiometric sensing method with few sample volumes, which requires the use of ion-selective electrodes (ISEs and reference electrodes. This review summarily descriptively presents progressive developments and applications of ion selective electrodes in medical laboratory electrolytic ion tests, from conventional ISEs, solid-contact ISEs, carbon nanotube based ISEs, to graphene-based ISEs.

  20. Using ion-selective electrodes to study the drug release from porous cellulose matrices

    DEFF Research Database (Denmark)

    Vakili, Hossein; Genina, Natalja; Ehlers, Henrik

    2012-01-01

    -polymer solutions were prepared with the model drugs, using different blend ratios of ethylcellulose (EC) and hydroxypropyl cellulose (HPC). Two different solid dosage forms were used. Polymer films were produced by solvent casting method and drug containing porous cellulose samples were prepared by depositing...... the drug-polymer solutions onto filter paper substrates. The quality of the electrodes and the release profile of Pr+ and Ld+ were investigated with \\r\

  1. An accurate and stable nitrate-selective electrode for the in situ determination of nitrate in agricultural drainage waters.

    Science.gov (United States)

    Le Goff, Thierry; Braven, Jim; Ebdon, Les; Chilcottt, Neil P; Scholefield, David; Wood, John W

    2002-04-01

    A field evaluation of a novel nitrate-ion selective electrode (ISE) was undertaken by continuous immersion over a period of 5 months in agricultural drainage weirs. The nitrate sensor N,N,N-triallyl leucine betaine was covalently attached to polystyrene-block-polybutadiene-block-polystyrene (SBS) using a free radical initiated co-polymerisation, to produce a rubbery membrane which was incorporated into a commercially available electrode body. A measurement unit was constructed comprising the nitrate-ISEs, a reference electrode and a temperature probe connected through a pre-amplifier to a data-logger and battery supply. A temperature correction algorithm was developed to accomodate the temperature changes encountered in the drainage weirs. The nitrate results obtained with the ISEs at hourly intervals compared very favourably (R2 = 0.99) with those obtained with laboratory automated chemical determinations made on contemporaneous samples of drainage in a concentration range 0.47-16 ppm nitrate-N. The ISEs did not require re-calibration and no deterioration in performance or fouling of the membrane surface was observed over four months of deployment.

  2. Development of a sensitive and selective Riboflavin sensor based on carbon ionic liquid electrode

    Energy Technology Data Exchange (ETDEWEB)

    Safavi, Afsaneh, E-mail: safavi@chem.susc.ac.ir [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Maleki, Norouz; Ershadifar, Hamid; Tajabadi, Fariba [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)

    2010-08-03

    The electrochemical properties of Riboflavin adsorbed on carbon ionic liquid electrode (CILE) were studied by cyclic voltammetry. A film with a surface coverage of up to 3.3 x 10{sup -9} mol cm{sup -2} was formed after 10 min exposure time. Electron transfer coefficient and rate constant of electron transfer across the modified electrode were found to be 0.43 and 3.03 s{sup -1}, respectively. Differential pulse voltammetry was used for the determination of Riboflavin. Two linear working ranges of 0.8-110 nM and 0.11-1.0 {mu}M were obtained with correlation coefficients of 0.998 and 0.996, respectively. The experimental detection limit was obtained as 0.1 nM. The relative standard deviation for five replicate analyses was 4.7%. Other soluble vitamins had no significant interferences and the electrode was used for the determination of Riboflavin in pharmaceutical products, nutrition and beverages.

  3. Simple and rapid mercury ion selective electrode based on 1-undecanethiol assembled Au substrate and its recognition mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xian-Qing; Liang, Hai-Qing [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); Cao, Zhong, E-mail: zhongcao2004@163.com [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); Xiao, Qing [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); Xiao, Zhong-Liang, E-mail: xiaozhongliang@163.com [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); State Key Laboratory of High Performance Complex Manufacturing, School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China); Song, Liu-Bin [Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114 (China); Chen, Dan [Hunan Airbluer Environmental Protection Technology Co., Ltd., Changsha 410014 (China); Wang, Fu-Liang [State Key Laboratory of High Performance Complex Manufacturing, School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China)

    2017-03-01

    A simple and rapid mercury ion selective electrode based on 1-undecanethiol (1-UDT) assembled Au substrate (Au/1-UDT) has been well constructed. 1-UDT was for the purpose of generating self-assembled monolayer on gold surface to recognize Hg{sup 2+} in aqueous solution, which had a working concentration range of 1.0 × 10{sup −} {sup 8}–1.0 × 10{sup −4} mol L{sup −1}, with a Nernst response slope of 28.83 ± 0.4 mV/-pC, a detection limit of 4.5 × 10{sup −9} mol L{sup −1}, and a good selectivity over the other tested cations. Also, the Au/1-UDT possessed good reproducibility, stability, and short response time. The recovery obtained for the determination of mercury ion in practical tremella samples was in the range of 99.8–103.4%. Combined electrochemical analysis and X-ray photoelectron spectroscopy (XPS) with quantum chemical computation, the probable recognition mechanism of the electrode for selective recognition of Hg{sup 2+} has been investigated. The covalent bond formed between mercury and sulfur is stronger than the one between gold and sulfur and thus prevents the adsorption of 1-UDT molecules on the gold surface. The quantum chemical computation with density functional theory further demonstrates that the strong interaction between the mercury atom and the sulfur atom on the gold surface leads to the gold sulfur bond ruptured and the gold mercury metallophilic interaction. - Highlights: • A simple and rapid mercury ion selective electrode has been well constructed. • The Au/1-UDT electrode for sensing Hg{sup 2+} has a sensitivity of 28.83 ± 0.4 mV/− pC. • The ISE method has a detection limit of Hg{sup 2+} down to 4.5 × 10{sup −9} mol L{sup −1}. • A mechanism with density functional theory for recognition of Hg{sup 2+} is developed. • The quantum chemical computation demonstrates Au-Hg metallophilic interaction.

  4. The determination of small amounts of fluoride in uranium compounds by use of an ion-selective electrode

    International Nuclear Information System (INIS)

    Shelton, B.M.

    1975-01-01

    A method is presented for the determination of fluoride in uranium metal and oxide at levels from 16 p.p.m. upwards. Uranium is separated from fluoride by extraction into a solution of di(2-ethylhexyl)-phosphoric acid (HDEHP) in carbon tetrachloride. The fluoride remaining in the aqueous phase is determined by potentiometric measurement with an ion-selective electrode. A correction is made for the fluoride lost during the dissolution or extraction step, or both, which is based on a determination of the apparent loss of fluoride on spiked samples that are taken through the whole procedure [af

  5. Application of carbon nanotubes-ionic liquid hybrid in a sensitive atorvastatin ion-selective electrode

    International Nuclear Information System (INIS)

    Jalali, Fahimeh; Ardeshiri, Moslem

    2016-01-01

    Atorvastatin (ATR) was determined by a potentiometric method. The ion-pair of ATR and cetyltrimethylammonium bromide (CTAB) was used as a suitable ionophore. A graphite paste electrode was modified with ATR-CTAB ion-pair, multiwalled carbon nanotubes (MWCNTs), and an ionic liquid, 1-butyl-3-mtehyl-imidazolium hexafluorophosphate (BMIMPF 6 ). The amounts of electrode ingredients were optimized (graphite powder: paraffin oil: ATR-CTAB: MWCNTs: BMIMPF 6 (58:26:5:8:3 w/w%). Surface characterization was done by using scanning electron microscopy. The potential measurements were recorded at optimized pH by using acetate buffer solution (0.1 mol L −1 , pH 5.5). At the above experimental conditions, calibration curve (E vs. log [ATR]) was linear (R 2 = 0.9977) in the concentration range of 1.0 × 10 −9 –1.0 × 10 −3 mol L −1 (0.0012–1209 mg L −1 ) of ATR with a Nernstian slope of 58.14 ± 0.2 mV decade −1 , and detection limit of 1.0 × 10 −9 mol L −1 (0.0013 mg L −1 ). After each injection of ATR to the buffer solution, the potential was stabilized in a very short time (average response time ~ 6 s) at 25 °C. The modified graphite paste electrode had a long lifetime (> 4 months). Recovery of the spiked drug to blood serum samples (95.3–98.2%) revealed the reliability of electrode response to ATR. Blood serum samples from consumers were analyzed by the proposed method; the results were comparable with those from HPLC standard method. The potentiometric analysis of ATR tablets by the proposed electrode resulted in a relative error of 0.8% and 1.5% for 20 and 40 mg per tablets, respectively. Finally, the electrode was used in potentiometric titration of ATR (1.0 × 10 −3 mol L −1 ) by CTAB (1.0 × 10 −3 mol L −1 ). Excellent accuracy (≈ 100%) was obtained from the volume of the titrant at the endpoint. - Graphical abstract: Graphite paste was modified with atorvastatin-CTAB (ATR-CTAB), ionic liquid (BMIMPF 6 ) and multiwalled carbon

  6. Application of carbon nanotubes-ionic liquid hybrid in a sensitive atorvastatin ion-selective electrode

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Fahimeh, E-mail: fjalali@razi.ac.ir; Ardeshiri, Moslem

    2016-12-01

    Atorvastatin (ATR) was determined by a potentiometric method. The ion-pair of ATR and cetyltrimethylammonium bromide (CTAB) was used as a suitable ionophore. A graphite paste electrode was modified with ATR-CTAB ion-pair, multiwalled carbon nanotubes (MWCNTs), and an ionic liquid, 1-butyl-3-mtehyl-imidazolium hexafluorophosphate (BMIMPF{sub 6}). The amounts of electrode ingredients were optimized (graphite powder: paraffin oil: ATR-CTAB: MWCNTs: BMIMPF{sub 6} (58:26:5:8:3 w/w%). Surface characterization was done by using scanning electron microscopy. The potential measurements were recorded at optimized pH by using acetate buffer solution (0.1 mol L{sup −1}, pH 5.5). At the above experimental conditions, calibration curve (E vs. log [ATR]) was linear (R{sup 2} = 0.9977) in the concentration range of 1.0 × 10{sup −9}–1.0 × 10{sup −3} mol L{sup −1} (0.0012–1209 mg L{sup −1}) of ATR with a Nernstian slope of 58.14 ± 0.2 mV decade{sup −1}, and detection limit of 1.0 × 10{sup −9} mol L{sup −1} (0.0013 mg L{sup −1}). After each injection of ATR to the buffer solution, the potential was stabilized in a very short time (average response time ~ 6 s) at 25 °C. The modified graphite paste electrode had a long lifetime (> 4 months). Recovery of the spiked drug to blood serum samples (95.3–98.2%) revealed the reliability of electrode response to ATR. Blood serum samples from consumers were analyzed by the proposed method; the results were comparable with those from HPLC standard method. The potentiometric analysis of ATR tablets by the proposed electrode resulted in a relative error of 0.8% and 1.5% for 20 and 40 mg per tablets, respectively. Finally, the electrode was used in potentiometric titration of ATR (1.0 × 10{sup −3} mol L{sup −1}) by CTAB (1.0 × 10{sup −3} mol L{sup −1}). Excellent accuracy (≈ 100%) was obtained from the volume of the titrant at the endpoint. - Graphical abstract: Graphite paste was modified with atorvastatin

  7. Improved sensitivity and selectivity of uric acid voltammetric sensing with mechanically grinded carbon/graphite electrodes

    Czech Academy of Sciences Publication Activity Database

    Hasoň, Stanislav; Vetterl, Vladimír; Jelen, František; Fojta, Miroslav

    2009-01-01

    Roč. 54, č. 6 (2009), s. 1864-1873 ISSN 0013-4686 R&D Projects: GA AV ČR(CZ) KAN200040651; GA ČR(CZ) GA203/07/1195; GA MŠk(CZ) LC06035; GA ČR(CZ) GA202/08/1688; GA AV ČR(CZ) IAA400040804 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : grinded carbon electrodes * voltammetry * uric acid Subject RIV: AQ - Safety, Health Protection, Human - Machine Impact factor: 3.325, year: 2009

  8. UV-assisted selective chemical etching of relief gratings in Er/Yb-codoped IOG1 phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Pappas, C; Pissadakis, S [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, Vasilika Vouton, PO Box 1527, Heraklion 71 110, GREECE (Greece)

    2007-04-15

    The patterning of sub-micron periodicity Bragg reflectors in Er/Yb-codoped IOG1, phosphate glass is demonstrated. A high yield patterning technique is presented, wherein high volume damage is induced into the glass matrix by exposure to intense UV radiation, and subsequently a chemical development in a strong acid selectively etches the exposed areas. The grating reflectors were fabricated by employing an elliptical Talbot interferometer and the output of a 213nm, 150ps frequency quintupled Nd:YAG laser. The grating depth of the etched relief pattern in time was measured at fixed time intervals and the dependence is presented in upon the etching time and exposure conditions. The gratings fabricated are examined by atomic and scanning electron microscopy for revealing the topology of the relief structure. Gratings with period of the order of 500nm were fabricated, having a maximum depth of 60nm.

  9. β-cyclodextrin functionalized on glass micro-particles: A green catalyst for selective oxidation of toluene to benzaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Tahir, M. Nazir, E-mail: tahir.muhammad_nazir@courrier.uqam.ca [Department of Chemistry and Bioscience, Aalborg University, Frederik Bajers Vej 7H, DK-9220, Aalborg East (Denmark); Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8 (Canada); Nielsen, Thorbjørn T.; Larsen, Kim L. [Department of Chemistry and Bioscience, Aalborg University, Frederik Bajers Vej 7H, DK-9220, Aalborg East (Denmark)

    2016-12-15

    Highlights: • Functionalization of βCD onto glass micro-particles (GMP-βCD). • Application of GMP-βCD as a green catalyst for the oxidation of toluene. • 82% yield at room temperature. • Repeated use of the catalyst for several cycles. - Abstract: Oxidation of toluene is considered an important process which often requires high temperatures and specific conditions along with heavy-metals based catalysts. In this study, we have developed a green catalyst by functionalizing beta-cyclodextrin onto glass micro-particle surfaces. All surfaces were characterized by X-ray photoelectron spectroscopy and applied to catalyze the selective oxidation of toluene into benzaldehyde (82% yield) at room temperature. The catalyst was stable and could be used repeatedly for several cycles without losing efficiency.

  10. Highly sensitive and selective determination of methylergometrine maleate using carbon nanofibers/silver nanoparticles composite modified carbon paste electrode

    International Nuclear Information System (INIS)

    Kalambate, Pramod K.; Rawool, Chaitali R.; Karna, Shashi P.; Srivastava, Ashwini K.

    2016-01-01

    A highly sensitive and selective voltammetric method for determination of Methylergometrine maleate (MM) in pharmaceutical formulations, urine and blood serum samples has been developed based on enhanced electrochemical response of MM at carbon nanofibers and silver nanoparticles modified carbon paste electrode (CNF-AgNP-CPE). The electrode material was characterized by various techniques viz., X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic response of MM at CNF-AgNP-CPE was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimized conditions, the proposed sensor exhibits excellent electrochemical response towards MM. The DPV study shows greatly enhanced electrochemical signal for MM at CNF-AgNP-CPE lending high sensitivity to the proposed sensor for MM detection. The peak (I p ) current for MM is found to be rectilinear in the range 4.0 × 10 −8 –2.0 × 10 −5 M with a detection limit of 7.1 × 10 −9 M using DPV. The feasibility of the proposed sensor in analytical applications was investigated by conducting experiments on commercial pharmaceutical formulations, human urine and blood serum samples, which yielded satisfactory recoveries of MM. The proposed electrochemical sensor offers high sensitivity, selectivity, reproducibility and practical utility. We recommend it as an authentic and productive electrochemical sensor for successful determination of MM. - Highlights: • Voltammetric sensor for methylergometrine maleate using carbon nanofibers and silver nanoparticle - carbon paste electrode • Wide working range, good reproducibility, fast response and high stability were the main advantages of the proposed sensor • Analysis of methylergometrine maleate in pharmaceutical formulations, urine and blood serum samples • Lowest limit of detection obtained for methylergometrine maleate

  11. Antibacterial effects and dissolution behavior of six bioactive glasses.

    Science.gov (United States)

    Zhang, Di; Leppäranta, Outi; Munukka, Eveliina; Ylänen, Heimo; Viljanen, Matti K; Eerola, Erkki; Hupa, Mikko; Hupa, Leena

    2010-05-01

    Dissolution behavior of six bioactive glasses was correlated with the antibacterial effects of the same glasses against sixteen clinically important bacterial species. Powdered glasses (<45 microm) were immersed in simulated body fluid (SBF) for 48 h. The pH in the solution inside the glass powder was measured in situ with a microelectrode. After 2, 4, 27, and 48 h, the pH and concentration of ions after removing the particles and mixing the SBF were measured with a normal glass pH electrode and ICP-OES. The bacteria were cultured in broth with the glass powder for up to 4 days, after which the viability of the bacteria was determined. The antibacterial effect of the glasses increased with increasing pH and concentration of alkali ions and thus with increased dissolution tendency of the glasses, but it also depended on the bacterium type. The changes in the concentrations of Si, Ca, Mg, P, and B ions in SBF did not show statistically significant influence on the antibacterial property. Bioactive glasses showed strong antibacterial effects for a wide selection of aerobic bacteria at a high sample concentration (100 mg/mL). The antibacterial effects increased with glass concentration and a concentration of 50 mg/mL (SA/V 185 cm(-1)) was required to generate the bactericidal effects. Understanding the dissolution mechanisms of bioactive glasses is essential when assessing their antibacterial effects. Copyright 2009 Wiley Periodicals, Inc.

  12. Studies on the matched potential method for determining the selectivity coefficients of ion-selective electrodes based on neutral ionophores: experimental and theoretical verification.

    Science.gov (United States)

    Tohda, K; Dragoe, D; Shibata, M; Umezawa, Y

    2001-06-01

    A theory is presented that describes the matched potential method (MPM) for the determination of the potentiometric selectivity coefficients (KA,Bpot) of ion-selective electrodes for two ions with any charge. This MPM theory is based on electrical diffuse layers on both the membrane and the aqueous side of the interface, and is therefore independent of the Nicolsky-Eisenman equation. Instead, the Poisson equation is used and a Boltzmann distribution is assumed with respect to all charged species, including primary, interfering and background electrolyte ions located at the diffuse double layers. In this model, the MPM-selectivity coefficients of ions with equal charge (ZA = ZB) are expressed as the ratio of the concentrations of the primary and interfering ions in aqueous solutions at which the same amounts of the primary and interfering ions permselectively extracted into the membrane surface. For ions with unequal charge (ZA not equal to ZB), the selectivity coefficients are expressed as a function not only of the amounts of the primary and interfering ions permeated into the membrane surface, but also of the primary ion concentration in the initial reference solution and the delta EMF value. Using the measured complexation stability constants and single ion distribution coefficients for the relevant systems, the corresponding MPM selectivity coefficients can be calculated from the developed MPM theory. It was found that this MPM theory is capable of accurately and precisely predicting the MPM selectivity coefficients for a series of ion-selective electrodes (ISEs) with representative ionophore systems, which are generally in complete agreement with independently determined MPM selectivity values from the potentiometric measurements. These results also conclude that the assumption for the Boltzmann distribution was in fact valid in the theory. The recent critical papers on MPM have pointed out that because the MPM selectivity coefficients are highly concentration

  13. Positive dielectrophoresis used for selective trapping of nanoparticles from flue gas in a gradient field electrodes device

    Energy Technology Data Exchange (ETDEWEB)

    Lungu, Mihail, E-mail: lmihai@physics.uvt.ro; Neculae, Adrian; Lungu, Antoanetta [West University of Timisoara, Faculty of Physics (Romania)

    2015-12-15

    This paper investigates the possibility to use positive dielectrophoresis (pDEP) for selective trapping of nanoparticle dispersed in flue gas in a vertical pDEP-based microfluidic system. The experimental gradient field electrodes device contains as main part a vertical deposition plate with parallel planar electrodes in single connection on an insulating substrate, parallel to the reference electrode—a dielectric plate with a metalized side. The performances of the device were described and analyzed by numerical simulations and experimental tests in terms of two new specific parameters, called Retention rate and Filtration, related to the trapping of nanoparticles in suspension inside the device and the consequent purification of flue gas. It is outlined, both numerically and experimentally, that the concentration of particles trapped inside the device decreases as they are moving away from the inlet zone. The experimental results also highlight the nanoparticle size distribution of the particles collected from the deposition plate, using a nanoparticle tracking analysis method, and their selective capture on the deposition plate, depending on the amplitude and shape of the applied voltage, in a good agreement with the numerical simulations results.

  14. Highly sensitive and selective determination of methylergometrine maleate using carbon nanofibers/silver nanoparticles composite modified carbon paste electrode.

    Science.gov (United States)

    Kalambate, Pramod K; Rawool, Chaitali R; Karna, Shashi P; Srivastava, Ashwini K

    2016-12-01

    A highly sensitive and selective voltammetric method for determination of Methylergometrine maleate (MM) in pharmaceutical formulations, urine and blood serum samples has been developed based on enhanced electrochemical response of MM at carbon nanofibers and silver nanoparticles modified carbon paste electrode (CNF-AgNP-CPE). The electrode material was characterized by various techniques viz., X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic response of MM at CNF-AgNP-CPE was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimized conditions, the proposed sensor exhibits excellent electrochemical response towards MM. The DPV study shows greatly enhanced electrochemical signal for MM at CNF-AgNP-CPE lending high sensitivity to the proposed sensor for MM detection. The peak (Ip) current for MM is found to be rectilinear in the range 4.0×10(-8)-2.0×10(-5)M with a detection limit of 7.1×10(-9)M using DPV. The feasibility of the proposed sensor in analytical applications was investigated by conducting experiments on commercial pharmaceutical formulations, human urine and blood serum samples, which yielded satisfactory recoveries of MM. The proposed electrochemical sensor offers high sensitivity, selectivity, reproducibility and practical utility. We recommend it as an authentic and productive electrochemical sensor for successful determination of MM. Copyright © 2016. Published by Elsevier B.V.

  15. Screen-Printed Carbon Electrodes Modified with Cobalt Phthalocyanine for Selective Sulfur Detection in Cosmetic Products

    Directory of Open Access Journals (Sweden)

    Ying Shih

    2011-06-01

    Full Text Available Cobalt phthalocyanine (CoPc films were deposited on the surface of a screen-printed carbon electrode using a simple drop coating method. The cyclic voltammogram of the resulting CoPc modified screen-printed electrode (CoPc/SPE prepared under optimum conditions shows a well-behaved redox couple due to the (CoI/CoII system. The CoPc/SPE surface demonstrates excellent electrochemical activity towards the oxidation of sulfur in a 0.01 mol·L−1 NaOH. A linear calibration curve with the detection limit (DL, S/N = 3 of 0.325 mg·L−1 was achieved by CoPc/SPE coupled with flow injection analysis of the sulfur concentration ranging from 4 to 1120 mg·L−1. The precision of the system response was evaluated (3.60% and 3.52% RSD for 12 repeated injections, in the range of 64 and 480 mg·L−1 sulfur. The applicability of the method was successfully demonstrated in a real sample analysis of sulfur in anti-acne creams, and good recovery was obtained. The CoPc/SPE displayed several advantages in sulfur determination including easy fabrication, high stability, and low cost.

  16. Laboratory Evaluation of Ion-Selective Electrodes for Simultaneous Analysis of Macronutrients in Hydroponic Solution

    Science.gov (United States)

    Automated sensing of macronutrients in hydroponic solution would allow more efficient management of nutrients for crop growth in closed hydroponic systems. Ion-selective microelectrode technology requires an ion-selective membrane or a solid metal material that responds selectively to one analyte in...

  17. Handbook of reference electrodes

    CERN Document Server

    Inzelt, György; Scholz, Fritz

    2013-01-01

    Reference Electrodes are a crucial part of any electrochemical system, yet an up-to-date and comprehensive handbook is long overdue. Here, an experienced team of electrochemists provides an in-depth source of information and data for the proper choice and construction of reference electrodes. This includes all kinds of applications such as aqueous and non-aqueous solutions, ionic liquids, glass melts, solid electrolyte systems, and membrane electrodes. Advanced technologies such as miniaturized, conducting-polymer-based, screen-printed or disposable reference electrodes are also covered. Essen

  18. Analytical application of solid contact ion-selective electrodes for determination of copper and nitrate in various food products and drinking water.

    Science.gov (United States)

    Wardak, Cecylia; Grabarczyk, Malgorzata

    2016-08-02

    A simple, fast and cheap method for monitoring copper and nitrate in drinking water and food products using newly developed solid contact ion-selective electrodes is proposed. Determination of copper and nitrate was performed by application of multiple standard additions technique. The reliability of the obtained results was assessed by comparing them using the anodic stripping voltammetry or spectrophotometry for the same samples. In each case, satisfactory agreement of the results was obtained, which confirms the analytical usefulness of the constructed electrodes.

  19. PLZT capacitor on glass substrate

    Science.gov (United States)

    Fairchild, M. Ray; Taylor, Ralph S.; Berlin, Carl W.; Wong, Celine W. K.; Ma, Beihai; Balachandran, Uthamalingam

    2016-01-05

    A lead-lanthanum-zirconium-titanate (PLZT) capacitor on a substrate formed of glass. The first metallization layer is deposited on a top side of the substrate to form a first electrode. The dielectric layer of PLZT is deposited over the first metallization layer. The second metallization layer deposited over the dielectric layer to form a second electrode. The glass substrate is advantageous as glass is compatible with an annealing process used to form the capacitor.

  20. Validation of an ion selective electrode system for the analysis of serum fluoride ion

    OpenAIRE

    Duly, Ellie B.; Luney, Stephen R.; Trinick, Thomas R.; Murray, James M.; Comer, John E. A.

    1995-01-01

    A high impedance unit was developed for use with a fluoride/pH electrode system for the measurement of serum fluoride. The linearity, accuracy, precision and detection limit of the system is reported. At a pH of 1.55, the system was linear over a range of serum fluoride concentrations up to 100 μmol l-1, with a lower limit of detection of 0.3 μmol l-1. Recoveries at this pH were 94-105% in the range 2.6-100 μmol l-1. Within-run CVs ranged from 4.2% at a level of 2.3 μmol l-1 to 1.2% at a leve...

  1. A Cadmium Ion-selective Membrane Electrode Based on Strong Acidic Organic-inorganic Composite Cation-exchanger: Polyaniline Ce(IV Molybdate

    Directory of Open Access Journals (Sweden)

    Syed Ashfaq NABI

    2008-05-01

    Full Text Available A cadmium ion-selective composite cation-exchanger polyaniline Ce(IV molybdate was used as electroactive component for the construction of a ion-selective membrane electrode. The membrane electrode showed a Nerstian response for Cd(II ions over a wide concentration range 5 × 10-6 – 1 × 10-1 with a sub-Nerstian slope of 27 mV per decade change in concentration of cadmium ions. The limit of detection was also ascertained to be 5 × 10-6 M. It has a fast response time 15 s and can be very well utilized for more than three months with out any appreciable divergence in potentials. The optimum pH for the smooth functioning of this electrode was found to be in the Ph range of 2.5 – 7.5. The electrode also showed better selectivity for Cd(II ions over many other interfering ions. The practical utility of membrane electrode was demonstrated by using as indicator electrode for the potentiometric titration of Cd(II with EDTA and determination of cadmium content in drain water.

  2. Construction and performance characterization of ion-selective electrodes for potentiometric determination of pseudoephedrine hydrochloride applying batch and flow injection analysis techniques.

    Science.gov (United States)

    Zayed, Sayed I M; Issa, Yousry M; Hussein, Ahmed

    2006-01-01

    New pseudoephedrine selective electrodes have been constructed of the conventional polymer membrane type by incorporation of pseudoephedrine-phosphotungstate (PE-PT) or pseudoephedrine-silicotungstate (PE-SiT) ion-associates in a poly vinyl chloride (PVC) membrane plasticized with dibutyl phthalate (DBP). The electrodes were fully characterized in terms of the membrane composition, temperature, and pH. The electrodes exhibited mean slopes of calibration graphs of 57.09 and 56.10 mV concentration decade(-1) of PECl at 25 degrees C for (PE-PT) and (PE-SiT) electrodes, respectively. The electrodes showed fast, stable, and near-Nernstian response over the concentration ranges 6.31 x 10(-6)-1.00 x 10(-2) and 5.00 x 10(-5)-1.00x10(-2) M in the case of PE-PT applying batch and flow injection (FI) analysis, respectively, and 1.00 x 10(-5)-1.00 x 10(-2) and 5.00 x 10(-5)-1.00x10(-2) M in the case of PE-SiT for batch and FI analysis system, respectively. Detection limit was 5.01x 10(-6) M for PE-PT electrode and 6.31x10(-6) M for PE-SiT electrode. The electrodes were successfully applied for the potentiometric determination of pseudoephedrine hydrochloride (PECl) in pharmaceutical preparations with mean recovery 101.13 +/- 0.85% and 100.77+0.79% in case of PE-PT applying batch and flow injection systems, respectively, and 100.75+0.85% and 100.79 +/- 0.77% in case of PE-SiT for batch and flow injection systems, respectively. The electrodes exhibited good selectivity for PECl with respect to a large number of inorganic cations, sugars and amino acids.

  3. Fabrication and characterization of a nanometer-sized optical fiber electrode based on selective chemical etching for scanning electrochemical/optical microscopy.

    Science.gov (United States)

    Maruyama, Kenichi; Ohkawa, Hiroyuki; Ogawa, Sho; Ueda, Akio; Niwa, Osamu; Suzuki, Koji

    2006-03-15

    We have already reported a method for fabricating ultramicroelectrodes (Suzuki, K. JP Patent, 2004-45394, 2004). This method is based on the selective chemical etching of optical fibers. In this work, we undertake a detailed investigation involving a combination of etched optical fibers with various types of tapered tip (protruding-shape, double- (or pencil-) shape and triple-tapered electrode) and insulation with electrophoretic paint. Our goal is to establish a method for fabricating nanometer-sized optical fiber electrodes with high reproducibility. As a result, we realized pencil-shaped and triple-tapered electrodes that had radii in the nanometer range with high reproducibility. These nanometer-sized electrodes showed well-defined sigmoidal curves and stable diffusion-limited responses with cyclic voltammetry. The pencil-shaped optical fiber, which has a conical tip with a cone angle of 20 degrees , was effective for controlling the electrode radius. The pencil-shaped electrodes had higher reproducibility and smaller electrode radii (r(app) etched optical fiber electrodes. By using a pencil-shaped electrode with a 105-nm radius as a probe, we obtained simultaneous electrochemical and optical images of an implantable interdigitated array electrode. We achieved nanometer-scale resolution with a combination of scanning electrochemical microscopy SECM and optical microscopy. The resolution of the electrochemical and optical images indicated sizes of 300 and 930 nm, respectively. The neurites of living PC12 cells were also successfully imaged on a 1.6-microm scale by using the negative feedback mode of an SECM.

  4. Titanium (III) cation selective electrode based on synthesized tris(2pyridyl) methylamine ionophore and its application in water samples

    Science.gov (United States)

    Rezayi, Majid; Karazhian, Reza; Abdollahi, Yadollah; Narimani, Leila; Sany, Seyedeh Belin Tavakoly; Ahmadzadeh, Saeid; Alias, Yatimah

    2014-04-01

    The introduction of low detection limit ion selective electrodes (ISEs) may well pave the way for the determination of trace targets of cationic compounds. This research focuses on the detection of titanium (III) cation using a new PVC-membrane sensor based on synthesized tris(2pyridyl) methylamine (tpm) ionophore. The application and validation of the proposed sensor was done using potentiometric titration, inductively coupled plasma atomic emission spectrometry (ICP-AES), and atomic absorption spectrometry (AAS). The membrane sensor exhibited a Nernstian response to the titanium (III) cation over a concentration range of 1.0 × 10-6-1.0 × 10-2 M and pH range from 1-2.5. The Nernstian slope, the lower of detection (LOD), and the response time (t95%) of the proposed sensor were 29.17 +/- 0.24 mV/dec, 7.9 × 10-7 M, and 20 s, respectively. The direct determination of 4-39 μg/ml of titanium (III) standard solution showed an average recovery of 94.60 and a mean relative standard deviation of 1.8 at 100.0 μg/ml. Finally, the utilization of the electrodes as end-point indicators for potentiometric titration with EDTA solutions for titanium (III) sensor was successfully carried out.

  5. Determination of Cd2+ in aqueous solution using polyindole-Ce(IV) vanadophosphate conductive nanocomposite ion-selective membrane electrode

    Science.gov (United States)

    Khan, Asif Ali; Quasim Khan, Mohd; Hussain, Rizwan

    2017-09-01

    In the present study an organic-inorganic nanocomposite ion exchanger Polyindole-Ce(IV) vanadophosphate (PIn-CVP) was synthesized via sol-gel process showing excellent ion exchange capacity (IEC‒1.90 meqg-1). The material was characterized by SEM, TEM, XRD, FTIR, and TGA. A heterogeneous ion exchange membrane of PIn-CVP (IEC‒0.90 meqg-1) was also prepared by solution casting method. PIn-CVP shows high electrical conductivity (5.5  ×  10-2 S cm-1) and it is stable up to 120 °C under ambient conditions. Cd2+ selective membrane electrode was fabricated and its linear working range (3.98  ×  10-7 M to 1.0  ×  10-1 M), response time (25 s), Nerstian slope 25.00 mV dec-1 and working pH range (4-7) were calculated. It was employed as an indicator electrode in the potentiometric titration of Cd2+.

  6. Determination of arsenate in water by anion selective membrane electrode using polyurethane–silica gel fibrous anion exchanger composite

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Asif Ali, E-mail: asifkhan42003@yahoo.com; Shaheen, Shakeeba, E-mail: shakeebashaheen@ymail.com

    2014-01-15

    Highlights: • PU–Si gel is new anion exchanger material synthesized and characterized. • This material used as anion exchange membrane is applied for electroanalytical studies. • The method for detection and determination of AsO{sub 4}{sup 3−} in traces amounts discussed. • The results are also verified from arsenic analyzer. -- Abstract: Polyurethane (PU)–silica (Si gel) based fibrous anion exchanger composites were prepared by solid–gel polymerization of polyurethane in the presence of different amounts of silica gel. The formation of PU–Si gel fibrous anion exchanger composite was characterized by Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), scanning electron microscopy (SEM) and elemental analysis. The membrane having a composition of 5:3 (PU:Si gel) shows best results for water content, porosity, thickness and swelling. Our studies show that the present ion selective membrane electrode is selective for arsenic, having detection limit (1 × 10{sup −8} M to 1 × 10{sup −1} M), response time (45 s) and working pH range (5–8). The selectivity coefficient values for interfering ions indicate good selectivity for arsenate (AsO{sub 4}{sup 3−}) over interfering anions. The accuracy of the detection limit results was compared by PCA-Arsenomat.

  7. Devitrification kinetics and phase selection mechanisms in Cu-Zr metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kalay, Ilkay [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several hundred K/s. Some of the application products of BMGs include sporting goods, high performance springs and medical devices. Several rapid solidification techniques, including melt-spinning, atomization and surface melting have been developed to produce amorphous alloys. The aim of all these methods is to solidify the liquid phase rapidly enough to suppress the nucleation and growth of crystalline phases. Furthermore, the production of amorphous/crystalline composite (ACC) materials by partial crystallization of amorphous precursor has recently given rise to materials that provide better mechanical and magnetic properties than the monolithic amorphous or crystalline alloys. In addition, these advances illustrate the broad untapped potential of using the glassy state as an intermediate stage in the processing of new materials and nanostructures. These advances underlie the necessity of investigations on prediction and control of phase stability and microstructural dynamics during both solidification and devitrification processes. This research presented in this dissertation is mainly focused on Cu-Zr and Cu-Zr-Al alloy systems. The Cu-Zr binary system has high glass forming ability in a wide compositional range (35-70 at.% Cu). Thereby, Cu-Zr based alloys have attracted much attention according to fundamental

  8. Electrochemical Selective and Simultaneous Detection of Diclofenac and Ibuprofen in Aqueous Solution Using HKUST-1 Metal-Organic Framework-Carbon Nanofiber Composite Electrode

    Directory of Open Access Journals (Sweden)

    Sorina Motoc

    2016-10-01

    Full Text Available In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP and diclofenac (DCF in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA and multiple-pulsed amperometry (MPA. This electrode exhibited the possibility to selectively detect IBP and DCF by simple switching the detection potential using CA. However, the MPA operated under optimum working conditions of four potential levels selected based on CV shape in relation to the potential value, pulse time, and potential level number, and order allowed the selective/simultaneous detection of IBP and DCF characterized by the enhanced detection performance. For this application, the HKUST-CNF electrode exhibited a good stability and reproducibility of the results was achieved.

  9. Electrochemical Selective and Simultaneous Detection of Diclofenac and Ibuprofen in Aqueous Solution Using HKUST-1 Metal-Organic Framework-Carbon Nanofiber Composite Electrode.

    Science.gov (United States)

    Motoc, Sorina; Manea, Florica; Iacob, Adriana; Martinez-Joaristi, Alberto; Gascon, Jorge; Pop, Aniela; Schoonman, Joop

    2016-10-17

    In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP) and diclofenac (DCF) in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF) electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV) was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA) and multiple-pulsed amperometry (MPA). This electrode exhibited the possibility to selectively detect IBP and DCF by simple switching the detection potential using CA. However, the MPA operated under optimum working conditions of four potential levels selected based on CV shape in relation to the potential value, pulse time, and potential level number, and order allowed the selective/simultaneous detection of IBP and DCF characterized by the enhanced detection performance. For this application, the HKUST-CNF electrode exhibited a good stability and reproducibility of the results was achieved.

  10. Gadolinium(III Ion-Selective Electrode Based on 3-Methyl-1H-1,2,4-triazole-5-thiol

    Directory of Open Access Journals (Sweden)

    Hassan Ali Zamani

    2012-01-01

    Full Text Available The 3-methyl-1H-1,2,4-triazole-5-thiol (MTH was used as a suitable ionophore for fabrication of a new gadolinium(III ion selective potentiometric sensor. Nitrobenzene (NB was used as plasticizing solvent mediator and sodium tetraphenyl borate (NaTPB as an anion excluder. It displays a Nernstian response (19.8± 0.4 mV/decade in the concentration range of 1.0×10-7 to 1.0×10-2 M with the detection limit of 7.3×10-8 M. The sensor has a very short response time (<10s and can be used the pH range of 2.9-8.4. electrode was successfully applied as an indicator for gadolinium determination in titration with EDTA.

  11. Total cyanide mass measurement with micro-ion selective electrode for determination of specific activity of carbon-11 cyanide.

    Science.gov (United States)

    Shea, Colleen; Alexoff, David L; Kim, Dohyun; Hoque, Ruma; Schueller, Michael J; Fowler, Joanna S; Qu, Wenchao

    2015-08-01

    In this research, we aim to directly measure the specific activity (SA) of the carbon-11 cyanide ([(11)C]CN¯) produced by our in-house built automated [(11)C]HCN production system and to identify the major sources of (12)C-cyanide ((12)CN¯). The [(11)C]CN¯ is produced from [(11)C]CO2, which is generated by the (14)N(p,α)(11)C nuclear reaction using a cyclotron. Direct measurement of cyanide concentrations was accomplished using a relatively inexpensive, and easy to use ion selective electrode (ISE) which offered an appropriate range of sensitivity for detecting mass. Multiple components of the [(11)C]HCN production system were isolated in order to determine their relative contributions to (12)CN¯ mass. It was determined that the system gases were responsible for approximately 30% of the mass, and that the molecular sieve/nickel furnace unit contributed approximately 70% of the mass. Beam on target (33µA for 1 and 10min) did not contribute significantly to the mass. Additionally, we compared the SA of our [(11)C]HCN precursor determined using the ISE to the SA of our current [(11)C]CN¯ derived radiotracers determined by HPLC to assure there was no significant difference between the two methods. These results are the first reported use of an ion selective electrode to determine the SA of no-carrier-added cyanide ion, and clearly show that it is a valuable, inexpensive and readily available tool suitable for this purpose. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. A new ion selective electrode for cesium (I) based on calix[4]arene-crown-6 compounds.

    Science.gov (United States)

    Ramanjaneyulu, P S; Kumar, Abha Naveen; Sayi, Y S; Ramakumar, K L; Nayak, S K; Chattopadhyay, S

    2012-02-29

    A polyvinylchloride (PVC) based liquid membrane ion selective electrode (ISE) for cesium has been developed. 25,27-Dihydroxycalix[4]arene-crown-6 (L1), 5,11,17,23-tetra-tert-butyl-25,27-dimethoxycalix[4]arene-crown-6 (L2) and 25,27-bis(1-octyloxy)calix[4]arene-crown-6 (L3) were investigated for their use as ionophores. The cation exchange resin DOWEX-50W was used to maintain low activity Cs+ in inner filling solution to improve the performance. The best response for cesium was observed with L3 along with optimized membrane constituents and composition. Excellent Nernstian response (56.6 mV/decade of Cs(I)) over the concentration range 10(-7) to 10(-2)M of Cs(I) was obtained with a fast response time of less than 10s. Detection limit for Cs(I) using the present ISE is 8.48×10(-8) M Cs(I). Separate solution method (SSM) was applied to ascertain the selectivity for Cs(I) over alkali, alkaline earth and transition metal ions. The response of ISE for Cs(I) was fairly constant over the pH range of 4-11. The lifetime of the electrode is 10 months which is the highest life for any membrane based Cs-ISE so far developed. The concentration of cesium ion in two simulated high level active waste streams was determined and results agreed well with those obtained independently employing AAS. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Selective recurrent laryngeal nerve stimulation using a penetrating electrode array in the feline model.

    Science.gov (United States)

    Haidar, Yarah M; Sahyouni, Ronald; Moshtaghi, Omid; Wang, Beverly Y; Djalilian, Hamid R; Middlebrooks, John C; Verma, Sunil P; Lin, Harrison W

    2017-10-31

    Laryngeal muscles (LMs) are controlled by the recurrent laryngeal nerve (RLN), injury of which can result in vocal fold (VF) paralysis (VFP). We aimed to introduce a bioelectric approach to selective stimulation of LMs and graded muscle contraction responses. Acute experiments in cats. The study included six anesthetized cats. In four cats, a multichannel penetrating microelectrode array (MEA) was placed into an uninjured RLN. For RLN injury experiments, one cat received a standardized hemostat-crush injury, and one cat received a transection-reapproximation injury 4 months prior to testing. In each experiment, three LMs (thyroarytenoid, posterior cricoarytenoid, and cricothyroid muscles) were monitored with an electromyographic (EMG) nerve integrity monitoring system. Electrical current pulses were delivered to each stimulating channel individually. Elicited EMG voltage outputs were recorded for each muscle. Direct videolaryngoscopy was performed for visualization of VF movement. Stimulation through individual channels led to selective activation of restricted nerve populations, resulting in selective contraction of individual LMs. Increasing current levels resulted in rising EMG voltage responses. Typically, activation of individual muscles was successfully achieved via single placement of the MEA by selection of appropriate stimulation channels. VF abduction was predominantly observed on videolaryngoscopy. Nerve histology confirmed injury in cases of RLN crush and transection experiments. We demonstrated the ability of a penetrating MEA to selectively stimulate restricted fiber populations within the feline RLN and selectively elicit contractions of discrete LMs in both acute and injury-model experiments, suggesting a potential role for intraneural MEA implantation in VFP management. NA Laryngoscope, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  14. Fabrication of Stretchable Copper Coated Carbon Nanotube Conductor for Non-Enzymatic Glucose Detection Electrode with Low Detection Limit and Selectivity

    Directory of Open Access Journals (Sweden)

    Dawei Jiang

    2018-03-01

    Full Text Available The increasing demand for wearable glucose sensing has stimulated growing interest in stretchable electrodes. The development of the electrode materials having large stretchability, low detection limit, and good selectivity is the key component for constructing high performance wearable glucose sensors. In this work, we presented fabrication of stretchable conductor based on the copper coated carbon nanotube sheath-core fiber, and its application as non-enzymatic electrode for glucose detection with high stretchability, low detection limit, and selectivity. The sheath-core fiber was fabricated by coating copper coated carbon nanotube on a pre-stretched rubber fiber core followed by release of pre-stretch, which had a hierarchically buckled structure. It showed a small resistance change as low as 27% as strain increasing from 0% to 500% strain, and a low resistance of 0.4 Ω·cm−1 at strain of 500%. This electrode showed linear glucose concentration detection in the range between 0.05 mM and 5 mM and good selectivity against sucrose, lactic acid, uric acid, acrylic acid in phosphate buffer saline solution, and showed stable signal in high salt concentration. The limit of detection (LOD was 0.05 mM, for the range of 0.05–5 mM, the sensitivity is 46 mA·M−1. This electrode can withstand large strain of up to 60% with negligible influence on its performance.

  15. Selectivity of recording of neural signals with micromachined intraneural micro electrodes

    NARCIS (Netherlands)

    Rutten, Wim; Rozijn, T.H.; Rozijn, Tom H.; Meier, J.H.; Meier, Jan H.

    1993-01-01

    The number uf afferent fibers in a peripheral nerve fascicle and the electrical volume conduction in neuraI tissue determine the interelectrode spacing, needed for selective recording with mufticontact devices. These factors taking into account, and also assuming uniform distribution of fibers

  16. Selective electronalysis of peracetic acid in the presence of a large excess of H2O2 at Au(1 1 1)-like gold electrode

    International Nuclear Information System (INIS)

    Awad, M.I.

    2012-01-01

    Highlights: ► Analysis of peracetic acid in the presence of a large excess of H 2 O 2 is introduced. ► Au(1 1 1)-like gold electrode serves as an ideal for this purpose. ► The analysis is characterized by high selectivity and sensitivity. - Abstract: Peracetic acid (PAA) has been selectively electroanalyzed in the presence of a large excess of hydrogen peroxide (H 2 O 2 ), about 500 fold that of PAA, using Au (1 1 1)-like gold electrode in acetate buffer solutions of pH 5.4. Au(1 1 1)-like gold electrode was prepared by a controlled reductive desorption of a previously assembled thiol, typically cysteine, monolayer onto the polycrystalline gold (poly-Au) electrode. Cysteine molecules were selectively removed from the Au(1 1 1) facets of the poly-Au electrode, keeping the other two facets (i.e., Au(1 1 0) and Au(1 0 0)) under the protection of the adsorbed cysteine. It has been found that Au(1 1 1)-like gold electrode positively shifts the reduction peak of PAA, while, fortunately, shifts the reduction peak of H 2 O 2 negatively, achieving a large potential separation (around 750 mV) between the two reduction peaks as compared with that (around 450 mV) obtained at the poly-Au electrode. This large potential separation between the two reduction peaks enabled the analysis of PAA in the presence of a large excess of H 2 O 2 . In addition, the positive shift of the reduction peak of PAA gives the present method a high immunity against the interference of the dissolved oxygen.

  17. In situ preparation of NiS2/CoS2 composite electrocatalytic materials on conductive glass substrates with electronic modulation for high-performance counter electrodes of dye-sensitized solar cells

    Science.gov (United States)

    Li, Faxin; Wang, Jiali; Zheng, Li; Zhao, Yaqiang; Huang, Niu; Sun, Panpan; Fang, Liang; Wang, Lei; Sun, Xiaohua

    2018-04-01

    The electrocatalytic composite materials of honeycomb structure NiS2 nanosheets loaded with metallic CoS2 nanoparticles are in situ prepared on F doped SnO2 conductive glass (FTO) substrates used as counter electrodes of DSSCs through chemical bath deposition (CBD) and sulfidizing process. Single crystalline NiS2 honeycomb structure array lay a foundation for the large surface area of NiS2/CoS2 composite CEs. The formed NiS2/CoS2 nanointerface modulates electronic structure of composite CEs from the synergetic interactions between CoS2 nanoparticles and NiS2 nanosheets, which dramatically improves the electrocatalytic activity of NiS2/CoS2 composite CEs; Metallic CoS2 nanoparticles covering NiS2 nanosheets electrodes adjusts the electrodes' structure and then reduces the series resistance (Rs) and the Nernst diffusion resistance (Zw) of counter electrodes. The improvement of these areas greatly enhances the electrocatalytic performance of CEs and the short circuit current density (Jsc) and Fill factor (FF) of DSSCs. Impressively, the DSSC based on NiS2/CoS2-0.1 CE shows the best photovoltaic performance with photovoltaic conversion efficiency of 8.22%, which is 24.36% higher than that (6.61%) of the DSSC with Pt CE. And the NiS2/CoS2-0.1 CE also displays a good stability in the iodine based electrolyte. This work indicates that rational construction of composite electrocatalytic materials paves an avenue for high-performance counter electrodes of DSSCs.

  18. Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

    International Nuclear Information System (INIS)

    Kruger, A.A.

    1995-07-01

    This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading

  19. Selective Detection of Serotonin from the Interference by Ascorbic Acid and Uric Acid at Poly(thionine)-modified Glassy Carbon Electrode

    Energy Technology Data Exchange (ETDEWEB)

    Ahammad, A. J. Saleh; Nath, Narayan Chandra Deb; Kim, Sung Hyun [Konkuk University, Seoul (Korea, Republic of); Kim, Young Jun; Lee, Jae Joon [Konkuk University, Chungju (Korea, Republic of)

    2011-03-15

    Various approaches, such as using polymer film modified electrode, applying chemical modification, employing nano materials and molecularly imprinted polymers, have been developed to detect 5-HT selectively from interferences. The polymer-modified electrodes have widely been used because of their enhanced selectivity and sensitivity for many analytes. Previously, we have reported the role of poly(thionine) film (PTH) deposited on the electrochemically preanodized glassy carbon electrode (GCE) for the separation of the voltammetric signal of dopamine (DA) from that of AA and UA. In this communication, we are presenting the preliminary results of the electrochemical signal separation of 5-HT by suppressing those of AA and UA on another type PTH modified GCE (PTHGCE) which is prepared by electrochemical deposition of PTH directly on the mechanically polished GCE.

  20. Bi-enzyme L-arginine-selective amperometric biosensor based on ammonium-sensing polyaniline-modified electrode.

    Science.gov (United States)

    Stasyuk, Nataliya; Smutok, Oleh; Gayda, Galina; Vus, Bohdan; Koval'chuk, Yevgen; Gonchar, Mykhailo

    2012-01-01

    A novel L-arginine-selective amperometric bi-enzyme biosensor based on recombinant human arginase I isolated from the gene-engineered strain of methylotrophic yeast Hansenula polymorpha and commercial urease is described. The biosensing layer was placed onto a polyaniline-Nafion composite platinum electrode and covered with a calcium alginate gel. The developed sensor revealed a good selectivity to L-arginine. The sensitivity of the biosensor was 110 ± 1.3 nA/(mM mm(2)) with the apparent Michaelis-Menten constant (K(M)(app)) derived from an L-arginine (L-Arg) calibration curve of 1.27 ± 0.29 mM. A linear concentration range was observed from 0.07 to 0.6mM, a limit of detection being 0.038 mM and a response time - 10s. The developed biosensor demonstrated good storage stability. A laboratory prototype of the proposed amperometric biosensor was applied to the samples of three commercial pharmaceuticals ("Tivortin", "Cytrarginine", "Aminoplazmal 10% E") for L-Arg testing. The obtained L-Arg-content values correlated well with those declared by producers. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. YSZ-based sensor using Cr-Fe-based spinel-oxide electrodes for selective detection of CO.

    Science.gov (United States)

    Anggraini, Sri Ayu; Fujio, Yuki; Ikeda, Hiroshi; Miura, Norio

    2017-08-22

    A selective carbon monoxide (CO) sensor was developed by the use of both of CuCrFeO 4 and CoCrFeO 4 as the sensing electrode (SE) for yttria-stabilized zirconia (YSZ)-based potentiometric sensor. The sensing-characteristic examinations of the YSZ-based sensors using each of spinel oxides as the single-SE sensor showed that CuCrFeO 4 -SE had the ability to detect CO, hydrocarbons and NO x gases, while CoCrFeO 4 -SE was sensitive to hydrocarbons and NO x gases. Thus, when both SEs were paired as a combined-SEs sensor, the resulting sensor could generate a selective response to CO at 450 °C under humid conditions. The sensor was also capable of detecting CO in the concentration range of 20-700 ppm. Its sensing mechanism that was examined via polarization-curve measurements was confirmed to be based on mixed-potential model. The CO response generated by the combined-SEs sensor was unaffected by the change of water vapor concentration in the range of 1.3-11.5 vol% H 2 O. Additionally, the sensing performance was stable during 13 days tested. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Construction and evaluation of As(V) selective electrodes based on iron oxyhydroxide embedded in silica gel membrane

    International Nuclear Information System (INIS)

    Rodriguez, J.A.; Barrado, E.; Vega, M.; Prieto, F.; Lima, J.L.F.C.

    2005-01-01

    Two As(V) selective electrodes (with and without inner reference solution) have been developed using selective membranes based on iron oxyhydroxide embedded on silica gel mixed with ultrapure graphite at a 2/98 (w/w) ratio. The active component of the membrane was synthesised by means of the sol-gel technique and characterized by X-ray and FTIR spectroscopy. This compound shows a great affinity towards As(V) ions adsorbing 408 mg g -1 . Using 1 mol l -1 phosphate buffer (at a 1/1, v/v ratio) to adjust the pH and the ionic strength to 7 and 0.5 mol l -1 , respectively, the calibration curve is linear from 1.0 x 10 -1 to 1.0 x 10 -6 mol l -1 As(V), with a practical detection limit of 4 x 10 -7 mol l -1 (0.03 mg l -1 ) and a slope close to 30 mV decade -1 . The effect of potentially interfering ions was investigated. The accuracy and precision of the procedure have been tested on arsenic-free drinking water samples spiked with known amounts of arsenic and on groundwater samples containing high levels of arsenic. Total arsenic in these samples was determined after oxidation of As(III) with iodine at pH 7. The results of total As were comparable to those generated by ET-AAS

  3. Boronate-Modified Interdigitated Electrode Array for Selective Impedance-Based Sensing of Glycated Hemoglobin

    DEFF Research Database (Denmark)

    Boonyasit, Yuwadee; Laiwattanapaisal, Wanida; Chailapakul, Orawon

    2016-01-01

    An impedance-based label-free affinity sensor was developed for the recognition of glycated hemoglobin (HbA1c). Interdigitated gold microelectrode arrays (IDA) were first modified with a self-assembled monolayer of cysteamine followed by cross-linking with glutaraldehyde and subsequent binding of 3......-aminophenylboronic acid (APBA), which selectively binds HbA1c via cis-diol interactions. Impedance sensing was demonstrated to be highly responsive to the clinically relevant HbA1c levels (0.1%-8.36%) with a detection limit of 0.024% (3σ). The specificity of the assay was evaluated with non-glycated hemoglobin (Hb...

  4. Construction of a new selective coated disk electrode for Ag (I) based on modified polypyrrole-carbon nanotubes composite with new lariat ether.

    Science.gov (United States)

    Abbaspour, A; Tashkhourian, J; Ahmadpour, S; Mirahmadi, E; Sharghi, H; Khalifeh, R; Shahriyari, M R

    2014-01-01

    A poly (vinyl chloride) (PVC) matrix membrane ion-selective electrode for silver (I) ion is fabricated based on modified polypyrrole - multiwalled carbon nanotubes composite with new lariat ether. This sensor has a Nernstian slope of 59.4±0.5mV/decade over a wide linear concentration range of 1.0×10(-7) to 1.0×10(-1)molL(-1) for silver (I) ion. It has a short response time of about 8.0s and can be used for at least 50days. The detection limit is 9.3×10(-8)molL(-1) for silver (I) ion, and the electrode was applicable in the wide pH range of 1.6 -7.7. The electrode shows good selectivity for silver ion against many cations such as Hg (II), which usually imposes serious interference in the determination of silver ion concentration. The use of multiwalled carbon nanotubes (MWCNTs) in a polymer matrix improves the linear range and sensitivity of the electrode. In addition by coating the solid contact with a layer of the polypyrrole (Ppy) before coating the membrane on it, not only did it reduce the drift in potential, but a shorter response time was also resulted. The proposed electrode was used as an indicator electrode for potentiometric titration of silver ions with chloride anions and in the titration of mixed halides. This electrode was successfully applied for the determination of silver ions in silver sulphadiazine as a burning cream. © 2013.

  5. Determination of residence times of ions in a resistive glass selected ion flow-drift tube using the Hadamard transformation.

    Science.gov (United States)

    Spesyvyi, Anatolii; Španěl, Patrik

    2015-09-15

    Selected ion flow tube mass spectrometry, SIFT-MS, used for trace gas analyses has certain fundamental limitations that could be alleviated by adding a facility that allows reaction times and ion interaction energies to be varied. Thus, a selected ion flow-drift tube, SIFDT, has been created to explore the influence of an embedded electric field on these parameters and on reaction processes. The new SIFTD instrument was constructed using a miniature resistive glass drift tube. Arrival times of ions, t, analysed by a downstream quadrupole mass spectrometer over the m/z range 10-100 were studied by modulating the injected ion current using a gate lens. Single pulse modulation was compared with pseudorandom time multiplexing exploiting the Hadamard transformation. A simple model involving analysis of ethanol and water vapour mixture in air was used to explore the advantages of the SIFDT concept to SIFT-MS analysis. It is shown that the resistive glass drift tube is suitable for SIFDT experiments. The Hadamard transformation can be used to routinely determine reagent ion residence time in the flow-drift tube and also to observe differences in arrival times for different product ions. Two-dimensional data combining arrival time and mass spectra can be obtained rapidly. The calculated ion drift velocities vary with the reduced field strength, E/N, and the calculated ion mobilities agree with theoretical and previous literature values. This study has provided evidence that the SIFDT-MS technique can be implemented in a miniature and low-cost instrument and two- or three-dimensional data can be obtained (product ion count rates as functions of m/z, t and E/N) using the Hadamard transformation thus providing exciting possibilities for further analytical additions and extensions of the SIFT-MS technique. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Evaluation of the cytotoxicity of selected conventional glass ionomer cements on human gingival fibroblasts.

    Science.gov (United States)

    Marczuk-Kolada, Grażyna; Łuczaj-Cepowicz, Elżbieta; Pawińska, Małgorzata; Hołownia, Adam

    2017-10-01

    Dentistry materials are the most frequently used substitutes of human tissues. Therefore, an assessment of dental filling materials should cover not only their chemical, physical, and mechanical characteristics, but also their cytotoxicity. To compare the cytotoxic effects of 13 conventional glass ionomer cements on human gingival fibroblasts. The assessment was conducted using the MTT test. Six samples were prepared for each material. Culture plates with cells and inserts with the materials were incubated at 37°C, 5% CO2, and 95% humidity for 24 h. Then the inserts were removed, 1 mL of MTT was added in the amount of 0.5 mg/1 mL of the medium, and the samples were incubated in the described conditions without light for 2 h. The optical density was measured with an absorption spectrophotometer at a wavelength of 560 nm. The cytotoxic effects of the Argion Molar was significantly stronger than the Fuji Triage (p = 0.007), Chemfil Molar (p cements from the low cytotoxicity group were significantly more toxic vs materials whose presence resulted in fibroblast growth (p < 0.001). The research conducted indicates that, although the materials studied may belong to the same group, they are characterized by low, yet not uniform, cytotoxicity on human gingival fibroblasts. The toxic effects should not be assigned to a relevant group of materials, but each dentistry product should be evaluated individually.

  7. Potentiometer determination of sulfur using silver/sulfur ion selective electrodes; Determinacion potenciometrica de sulfuros mediante electrodo-ion-selectivo de plata/sulfuro

    Energy Technology Data Exchange (ETDEWEB)

    Salamanca Grosso, G. [Departamento de Quimica, Instituto de Ciencias, Universidad de Tolima, Tolima (Colombia)

    1996-06-01

    New devices in analytical chemistry, has been emerged, and new procedures take great interest. The use of electrodes ion selective are very important in water and wastewater control of Ag+/S= electrodes for control process in wastewater from UASE plan pilot, before check their potentiometric performance so: 28.6+- 0.4 mV/decade, optimal time 20 seconds, and pH>10, detection limit 1.8 x 10``-6. The study was made in comparative way with yodometrical method: we check quantification by addition, subtraction an GRANT`s titrimetric. (Author) 10 refs.

  8. Fabrication of novel coated graphite electrodes for the selective nano-level determination of Cd{sup 2+} ions in biological and environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Jitendra [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India); Singh, Ashok Kumar, E-mail: akscyfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India); Jain, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India)

    2011-10-30

    Novel cadmium selective coated graphite electrodes were prepared using three different ionophores N{sup 1}, N{sup 2}-dicyanoethyl-N{sup 1}, N{sup 2}-bis(pyridin-2-ylmethyl)benzene-1, 2-diamine [L{sub 1}], N{sup 1}, N{sup 2}-dicyanoethyl-N{sup 1}, N{sup 2}-bis(thiophen-2-ylmethyl) benzene-1, 2-diamine [L{sub 2}] and N{sup 1}, N{sup 2}-dicyanoethyl-N{sup 1}, N{sup 2}-bis(furan-2-ylmethyl)benzene-1, 2-diamine [L{sub 3}], and their potentiometric characteristics were determined. Membranes having different compositions of poly(vinylchloride) (PVC), the plasticizer o-nitrophenyloctylether (o-NPOE), sodium tetraphenylborate (NaTPB) as an anionic additive and ionophores were coated onto the graphite surface. The potential response measurements showed that the best performance was exhibited by the electrodes with membranes having the composition L{sub 1}: o-NPOE:NaTPB:PVC as 4:51:2.5:42.5 (wt.%), L{sub 2}: o-NPOE:NaTPB:PVC as 3:52.5:1.5:43 (wt.%) and L{sub 3}: o-NPOE:NaTPB:PVC as 7:49:3.5:40.5 (wt.%). These electrodes had the widest working concentration range, Nernstian slope and fast response times of 12 s, 7 s and 17 s for L{sub 1}, L{sub 2} and L{sub 3}, respectively. The selectivity studies showed that these electrodes have higher selectivity towards Cd{sup 2+} over a large number of cations and could tolerate up to 20 vol.% non-aqueous impurities. Furthermore, the electrodes generated constant potentials in the pH range 2.0-8.0, with a shelf life of approximately four to six weeks. The high selectivity of these electrodes permits their use in the detection of the Cd{sup 2+} content in some medicinal plants, soil and industrial wastewater samples. The electrodes could also be used as an indicator electrode in the potentiometric titration of Cd{sup 2+} with EDTA.

  9. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    International Nuclear Information System (INIS)

    Milly, Hussam; Andiappan, Manoharan; Thompson, Ian; Banerjee, Avijit

    2014-01-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  10. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    Energy Technology Data Exchange (ETDEWEB)

    Milly, Hussam [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Andiappan, Manoharan [Unit of Dental Public Health, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Thompson, Ian [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Banerjee, Avijit, E-mail: avijit.banerjee@kcl.ac.uk [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Unit of Conservative Dentistry, King' s College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom)

    2014-06-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  11. Preparation and characterization of electrically conducting polypyrrole Sn(IV phosphate cation-exchanger and its application as Mn(II ion selective membrane electrode

    Directory of Open Access Journals (Sweden)

    A.A. Khan

    2011-10-01

    Full Text Available Polypyrrole Sn(IV phosphate, an organic–inorganic composite cation-exchanger was synthesized via sol-gel mixing of an organic polymer, polypyrrole, into the matrices of the inorganic precipitate of Sn(IV phosphate. The physico-chemical properties of the material were determined using Atomic Absorption Spectrometry (AAS, CHN elemental analysis (inductively coupled plasma mass spectrometry, ICP-MS, UV–VIS spectrophotometry, FTIR (Fourier Transform Infra-Red, SEM (Scanning Electron Microscopy, TGA–DTA (Thermogravimetric Analysis–Differential Thermal Analysis, and XRD (X-ray diffraction. Ion-exchange behavior was observed to characterize the material. On the basis of distribution studies, the material was found to be highly selective for toxic heavy metal ion Mn2+. Due to its selective nature, the material was used as an electroactive component for the construction of an ion-selective membrane electrode. The proposed electrode shows fairly good discrimination of mercury ion over several other inorganic ions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations for Mn(II in water.

  12. Design of Smart Ion-Selective Electrode Arrays Based on Source Separation through Nonlinear Independent Component Analysis

    Directory of Open Access Journals (Sweden)

    Duarte L.T.

    2014-03-01

    Full Text Available The development of chemical sensor arrays based on Blind Source Separation (BSS provides a promising solution to overcome the interference problem associated with Ion-Selective Electrodes (ISE. The main motivation behind this new approach is to ease the time-demanding calibration stage. While the first works on this problem only considered the case in which the ions under analysis have equal valences, the present work aims at developing a BSS technique that works when the ions have different charges. In this situation, the resulting mixing model belongs to a particular class of nonlinear systems that have never been studied in the BSS literature. In order to tackle this sort of mixing process, we adopted a recurrent network as separating system. Moreover, concerning the BSS learning strategy, we develop a mutual information minimization approach based on the notion of the differential of the mutual information. The method works requires a batch operation, and, thus, can be used to perform off-line analysis. The validity of our approach is supported by experiments where the mixing model parameters were extracted from actual data.

  13. Determination of contaminants in boric acid used as neutron moderator by means of ion chromatography and selective electrodes

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Abrao, A.

    1988-07-01

    The boric acid used as neutron moderator in reactors must observe restrictions about the concentration of some impurities. According to Westinghouse (1) specification, the highest limits for sodium, sulphate, phosphate, fluoride, and chlorine are: Na + - 0,003%; SO 4 -2 - 0,0006%; PO 4 -3 - 0,003%; F - - 0,00002%; Cl - - 0,00004%. This paper describes the determination of ions above mentioned directly in the boric acid solution. The sample is dissolved in water or in an appropriate eluent and is injected in the ion chromatograph. Na + and F - are determined by means of selective electrodes. The determination limits found for F - (0,0002%) and Cl - (0,0002%) are not sufficiently low to attent the specifications. The determination limits found for SO 4 -2 (0,0005%), PO 4 -3 (0,0003%) and Na + (0,0005%) are good enough for nuclear pure boric acid analysis. In some samples nitrate (detection limit 0,0015%) was found as well. Boric acid from different suppliers were analysed. (author) [pt

  14. Experimental Study on Fabrication of AZO Transparent Electrode for Organic Solar Cell Using Selective Low-Temperature Atomic Layer Deposition

    International Nuclear Information System (INIS)

    Kim, Kicheol; Song, Gensoo; Kim, Hyungtae; Yoo, Kyunghoon; Kang, Jeongjin; Hwang, Junyoung; Lee, Sangho; Kang, Kyungtae; Kang, Heuiseok; Cho, Youngjune

    2013-01-01

    AZO (aluminum-doped zinc oxide) is one of the best candidate materials to replace Into (indium tin oxide) for TKOs (transparent conductive oxides) used in flat panel displays, organic light-emitting diodes (OLDS), and organic solar cells (OCSS). In the present study, to apply an AZO thin film to the transparent electrode of an organic solar cell, a low temperature selective atomic layer deposition (ALD) process was adopted to deposit an AZO thin film on a flexible polyethylene-naphthanate (Pen) substrate. The reactive gases for the ALD process were di-ethyl-zinc (De) and tri-methylaluminum (Tma) as precursors and H 2 O as an oxidant. The structural, electrical, and optical characteristics of the AZO thin film were evaluated. From the measured results of the electrical and optical characteristics of the AZO thin films deposited on the Pen substrates by Ald, it was shown that the Azo thin film appeared to be comparable to a commercially used Into thin film, which confirmed the feasibility of AZO as a TCO for flexible organic solar cells in the near future

  15. Development of phosphate glass microspheres containing holmium for selective internal radiotherapy; Desenvolvimento de microesferas de vidro fosfato contendo holmio para uso em radioterapia interna seletiva

    Energy Technology Data Exchange (ETDEWEB)

    Barros Filho, Eraldo Cordeiro

    2016-11-01

    The selective internal radiotherapy is an alternative for some kinds of cancer as the hepatocellular carcinoma (HCC) or primary liver cancer treatment. In this treatment, glass or polymer microspheres containing radionuclides inside their structure are introduced in the liver through hepatic artery and trapped at the arterioles that feed the tumor. In this work, the development of phosphate glasses containing holmium for production of microspheres and their application in Brazil are proposed. The developed glasses presented suitable chemical durability, density of 2,7(3) g/cm{sup 3}, high thermal stability and the impurities contained therein do not preclude the treatment. The microspheres were produced by the flame method and the gravitational fall method, and were characterized by means of several techniques to evaluate shape, average particle size, activity and biocompatibility suitable for selective internal radiotherapy. Based in the main results, the submission to in vivo tests is proposed. (author)

  16. Results of testing the Grambow rate law for use in HWVP glass durability correlations

    International Nuclear Information System (INIS)

    Kuhn, W.L.; Bunnell, L.R.

    1996-03-01

    A theory based on Grambow's work on hydration of glass as linear function of solution composition was evaluated. Use of Grambow's linear rate law for correlation of durability with glass composition is not recommended. Dissolution rate of the glass was determined using the rate of release of sodium with an ion selective electrode. This method was tested first applying it to initial dissolution rate of several glasses at several temperatures with zero initial concentration of silicic acid. HW39-2, HW39-4, and SRL-202 from Savannah River were tested; there was significant scatter in the data, with the dissolution rates of HW39 glasses and the SRL glass being comparable within this scatter. The dissolution rate of SRL-202 at 80 C and pH 7 for silicic acid concentrations 0, 25, 50, and 100% saturation, was found to decrease dramatically at only 25% of the saturated silicic acid concentration, which does not conform to the linear theory

  17. Construction of Eu3+ Ion-Selective Electrode Based on 1,2-Diaminopropane-N,N,N',N'-tetraacetic acid

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Abedi

    2011-01-01

    Full Text Available A new Eu3+ PVC membrane electrode based on 1,2-diaminopropane-N, N,N',N'-tetraacetic acid (DAPTA as a suitable ionophore has been prepared and studied. The electrode shows a good selectivity for Eu(III ion with respect to most common cations including alkali, alkaline earth, transition and heavy metal ions. This electrode has a wide linear dynamic range from 1.0×10-6 to 1.0×10-2 M with a Nernstian slope of 19.7±0.5 mV per decade and a low detection limit of 7.2×10-7 M in the pH range of 2.5–9.1, while the response time was rapid (<10 s. The practical utility of the electrodes has been demonstratedby their use as indicator electrodes in the potentiometric titration of Eu3+ ions with EDTA and for the determination of Eu3+ in some water sample solutions.

  18. PVC membrane, coated-wire, and carbon-paste ion-selective electrodes for potentiometric determination of galantamine hydrobromide in physiological fluids.

    Science.gov (United States)

    Abdel-Haleem, Fatehy M; Saad, Mohamed; Barhoum, Ahmed; Bechelany, Mikhael; Rizk, Mahmoud S

    2018-08-01

    We report on highly-sensitive ion-selective electrodes (ISEs) for potentiometric determining of galantamine hydrobromide (GB) in physiological fluids. Galantamine hydrobromide (GB) was selected for this study due to its previous medical importance for treating Alzheimer's disease. Three different types of ISEs were investigated: PVC membrane electrode (PVCE), carbon-paste electrode (CPE), and coated-wire electrode (CWE). In the construction of these electrodes, galantaminium-reineckate (GR) ion-pair was used as a sensing species for GB in solutions. The modified carbon-paste electrode (MCPE) was prepared using graphene oxide (MCPE-GO) and sodium tetrakis (trifluoromethyl) phenyl borate (MCPE-STFPB) as ion-exchanger. The potentiometric modified CPEs (MCPE-GO and MCPE-STFPB) show an improved performance in term of Nernstian slope, selectivity, response time, and response stability compared to the unmodified CPE. The prepared electrodes PVCE, CWE, CPE, MCPE-GO and MCPE-STFPB show Nernstian slopes of 59.9, 59.5, 58.1, 58.3 and 57.0 mV/conc. decade, and detection limits of 5.0 × 10 -6 , 6.3 × 10 -6 , 8.0 × 10 -6 , 6.0 × 10 -6 and 8.0 × 10 -6  mol L -1 , respectively. The prepared ISEs also show high selectivity against cations (i.e. Na + , K + , NH 4 + , Ca 2+ , Al 3+ , Fe 3+ ), amino acids (i.e. glycine, L-alanine alanine), and sugars (i.e. fructose, glucose, maltose, lactose). The prepared ISEs are applicable for determining GB in spiked serums, urines, and pharmaceutical preparations, using a standard addition and a direct potentiometric method. The fast response time (<10 s), long lifetime (1-5 weeks), reversibility and stability of the measured signals facilitate the application of these sensors for routine analysis of the real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. A polymeric membrane ion selective electrode based on organic-inorganic composite ion exchanger for the determination of thorium(IV)

    International Nuclear Information System (INIS)

    Chandra, Sulekh; Agarwal, Himanshu; Chandan Kumar, Singh; Sindhu, Susheel Kumar; Pankaj Kumar

    2005-01-01

    A poly(vinyl chloride) membrane electrode based on organic- inorganic composite ion exchanger, tin(IV) tungstoselenate-pyridine, has been prepared and tested for the selective determination of thorium(IV) ions. The PVC membrane electrode comprising 16% composite ion exchanger as the electroactive phase, 50% o-dioctyl phthalate as plasticizer, 4% tetraphenyl borate as anionic excluder and 30% poly(vinylchloride) displays a linear response to thorium(IV) ions over a wide concentration range of 1.0 x 10 -1 -8.0 x 10 -6 M with a Nernstain slope of 14.2 mV/ decade. The electrode shows a very short response time (∼15 s) and may be used in the pH range 2.5-9.0. The selectivity coefficient for alkali, alkaline earth and transition is smaller than 4.0 x 10 -4 . The sensor has been successfully used as an indicator electrode in the potentiometric titration of Th 4+ with EDTA as well as also for the determination of Th 4+ in the binary mixtures. (author)

  20. Selective Determination of Serotonin on Poly(3,4-ethylenedioxy pyrrole)-single-walled Carbon Nanotube-Modified Glassy Carbon Electrodes

    International Nuclear Information System (INIS)

    Kim, Seul Ki; Bae, Si Ra; Ahmed, Mohammad Shamsuddin; You, Jung Min; Jeon, Seung Won

    2011-01-01

    An electrochemically-modified electrode [P(EDOP-SWNTs)/GCE] was prepared by electropolymerization of 3,4-ethylenedioxy pyrrole (EDOP) single-walled carbon nanotubes (SWNTs) on the surface of a glassy carbon electrode (GCE) and characterized by SEM, CV, and DPV. This modified electrode was employed as an electrochemical biosensor for the selective determination of serotonin concentrations at pH 7.4 and exhibited a typical enhanced effect on the current response of serotonin with a lower oxidation overpotential. The linear response was in the range of 1.0 x 10"-"7 to 1.0 x 10"-"5 M, with a correlation coefficient of 0.998 on the anodic current. The lower detection limit was calculated as 5.0 nM. Due to the relatively low currents and difference of potentials in the electrochemical responses of uric acid (UA), ascorbic acid (AA), and dopamine (DA), the modified electrode was a useful and effective sensing device for the selective and sensitive serotonin determination in the presence of UA, AA, and DA

  1. Selective Determination of Serotonin on Poly(3,4-ethylenedioxy pyrrole)-single-walled Carbon Nanotube-Modified Glassy Carbon Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seul Ki; Bae, Si Ra; Ahmed, Mohammad Shamsuddin; You, Jung Min; Jeon, Seung Won [Chonnam National University, Gwangju (Korea, Republic of)

    2011-04-15

    An electrochemically-modified electrode [P(EDOP-SWNTs)/GCE] was prepared by electropolymerization of 3,4-ethylenedioxy pyrrole (EDOP) single-walled carbon nanotubes (SWNTs) on the surface of a glassy carbon electrode (GCE) and characterized by SEM, CV, and DPV. This modified electrode was employed as an electrochemical biosensor for the selective determination of serotonin concentrations at pH 7.4 and exhibited a typical enhanced effect on the current response of serotonin with a lower oxidation overpotential. The linear response was in the range of 1.0 x 10{sup -7} to 1.0 x 10{sup -5} M, with a correlation coefficient of 0.998 on the anodic current. The lower detection limit was calculated as 5.0 nM. Due to the relatively low currents and difference of potentials in the electrochemical responses of uric acid (UA), ascorbic acid (AA), and dopamine (DA), the modified electrode was a useful and effective sensing device for the selective and sensitive serotonin determination in the presence of UA, AA, and DA.

  2. Use of a silver ion selective electrode to assess mechanisms responsible for biological effects of silver nanoparticles

    International Nuclear Information System (INIS)

    Koch, Marcus; Kiefer, Silke; Cavelius, Christian; Kraegeloh, Annette

    2012-01-01

    For a detailed analysis of the biological effects of silver nanoparticles, discrimination between effects related to the nano-scale size of the particles and effects of released silver ions is required. Silver ions are either present in the initial particle dispersion or released by the nanoparticles over time. The aim of this study is to monitor the free silver ion activity {Ag + } in the presence of silver nanoparticles using a silver ion selective electrode. Therefore, silver in the form of silver nanoparticles, 4.2 ± 1.4 nm and 2–30 nm in size, or silver nitrate was added to cell culture media in the absence or presence of A549 cells as a model for human type II alveolar epithelial cells. The free silver ion activity measured after the addition of silver nanoparticles was determined by the initial ionic silver content. The p {Ag + } values indicated that the cell culture media decrease the free silver ion activity due to binding of silver ions by constituents of the media. In the presence of A549 cells, the free silver ion activity was further reduced. The morphology of A549 cells, cultivated in DME medium containing 9.1% (v/v) FBS, was affected by adding AgNO 3 at concentrations of ≥30 μM after 24 h. In comparison, silver nanoparticles up to a concentration of 200 μM Ag did not affect cellular morphology. Our experiments indicate that the effect of silver nanoparticles is mainly mediated by silver ions. An effect of silver on cellular morphology was observed at p {Ag + } ≤ 9.2.

  3. Interactions between poly(acrylic acid) and sodium dodecyl sulfate: isothermal titration calorimetric and surfactant ion-selective electrode studies.

    Science.gov (United States)

    Wang, C; Tam, K C

    2005-03-24

    Interaction between a monodispersed poly(acrylic acid) (PAA) (M(W) = 5670 g/mol, M(w)/M(n) = 1.02) with sodium dodecyl sulfate (SDS) was investigated using isothermal titration calorimetry (ITC), ion-selective electrode (ISE), and dynamic light scattering measurements. Contrary to previous studies, we report for the first time evidence of interaction between SDS and PAA when the degree of neutralization (alpha) of PAA is lower than 0.2. Hydrocarbon chains of SDS cooperatively bind to apolar segments of PAA driven by hydrophobic interaction. The interaction is both enthalpy and entropy favored (deltaH is negative but deltaS is positive). In 0.05 wt % PAA solution, the SDS concentration corresponding to the onset of binding (i.e., CAC) is approximately 2.4 mM and the saturation concentration (i.e., C(S)) is approximately 13.3 mM when alpha = 0. When PAA was neutralized and ionized, the binding was hindered by the enhanced electrostatic repulsion between negatively charged SDS and PAA chains and improved solubility of the polymer. With increasing alpha to 0.2, CAC increases to approximately 6.2 mM, C(S) drops to 8.6 mM, and the interaction is significantly weakened where the amount of bound SDS on PAA is reduced considerably. The values of CAC and C(S) derived from different techniques are in good agreement. The binding results in the formation of mixed micelles on apolar PAA coils, which then expands and dissociates into single PAA chains. The majority of unneutralized PAA molecules exist as single polymer chains stabilized by bound SDS micelles in solution after the saturation concentration.

  4. Stripping analysis of nanomolar perchlorate in drinking water with a voltammetric ion-selective electrode based on thin-layer liquid membrane.

    Science.gov (United States)

    Kim, Yushin; Amemiya, Shigeru

    2008-08-01

    A highly sensitive analytical method is required for the assessment of nanomolar perchlorate contamination in drinking water as an emerging environmental problem. We developed the novel approach based on a voltammetric ion-selective electrode to enable the electrochemical detection of "redox-inactive" perchlorate at a nanomolar level without its electrolysis. The perchlorate-selective electrode is based on the submicrometer-thick plasticized poly(vinyl chloride) membrane spin-coated on the poly(3-octylthiophene)-modified gold electrode. The liquid membrane serves as the first thin-layer cell for ion-transfer stripping voltammetry to give low detection limits of 0.2-0.5 nM perchlorate in deionized water, commercial bottled water, and tap water under a rotating electrode configuration. The detection limits are not only much lower than the action limit (approximately 246 nM) set by the U.S. Environmental Protection Agency but also are comparable to the detection limits of the most sensitive analytical methods for detecting perchlorate, that is, ion chromatography coupled with a suppressed conductivity detector (0.55 nM) or electrospray ionization mass spectrometry (0.20-0.25 nM). The mass transfer of perchlorate in the thin-layer liquid membrane and aqueous sample as well as its transfer at the interface between the two phases were studied experimentally and theoretically to achieve the low detection limits. The advantages of ion-transfer stripping voltammetry with a thin-layer liquid membrane against traditional ion-selective potentiometry are demonstrated in terms of a detection limit, a response time, and selectivity.

  5. Comparison of the Amount of Fluoride Release from Nanofilled Resin Modified Glass Ionomer Conventional and Resin Modified Glass Ionomer Cements

    Directory of Open Access Journals (Sweden)

    Sumitha Upadhyay

    2013-01-01

    Full Text Available Objective: To investigate and compare the amount of fluoride release of conventional, resin modified and nanofilled resin modified glass ionomer cements.Materials and Methods: Tablets of glass-ionomer cements were immersed in deionized water and incubated at 37◦C. After 1, 2, 7, 15 and 30 days, fluoride ion was measured under normal atmospheric conditions by fluoride ion selective electrode. Buffer (TISAB II was used to decomplex the fluoride ion and to provide a constant background ionic strength and to maintain the pH of water between 5.0 and 5.5 as the fluoride electrode is sensitive to changes in pH. Statistical evaluation was carried out by one way ANOVA (Analysis of Variance using SPSS 11.0. The significance level was set at p< 0.05.Results: The release of fluoride was highest on day 1 and there was a sudden fall on day 2 in all three groups. Initially fluoride release from conven-tional glass-ionomer cement was highest compared to the other two glass-ionomer cements, but the amount drastically reduced over the period. Although the amount of fluoride release was less than both the resin modified and nanofilled resin modified glass-ionomer cement, the release was sustained consistently for 30 daysConclusion: The cumulative fluoride release of nanofilled resin modified glass ionomer cement was very less compared to the conventional and resin modified glass ionomer cements and Nanofilled resin modified glass ionomer cement released less but steady fluoride as compared to other resin modified glass ionomer cements.

  6. Graphene nanocomposites for electrochemical cell electrodes

    Science.gov (United States)

    Zhamu, Aruna; Jang, Bor Z.; Shi, Jinjun

    2015-11-19

    A composite composition for electrochemical cell electrode applications, the composition comprising multiple solid particles, wherein (a) a solid particle is composed of graphene platelets dispersed in or bonded by a first matrix or binder material, wherein the graphene platelets are not obtained from graphitization of the first binder or matrix material; (b) the graphene platelets have a length or width in the range of 10 nm to 10 .mu.m; (c) the multiple solid particles are bonded by a second binder material; and (d) the first or second binder material is selected from a polymer, polymeric carbon, amorphous carbon, metal, glass, ceramic, oxide, organic material, or a combination thereof. For a lithium ion battery anode application, the first binder or matrix material is preferably amorphous carbon or polymeric carbon. Such a composite composition provides a high anode capacity and good cycling response. For a supercapacitor electrode application, the solid particles preferably have meso-scale pores therein to accommodate electrolyte.

  7. Patterning Method for Silver Nanoparticle Electrodes in Fully Solution-Processed Organic Thin-Film Transistors Using Selectively Treated Hydrophilic and Hydrophobic Surfaces

    Science.gov (United States)

    Fukuda, Kenjiro; Takeda, Yasunori; Kobayashi, Yu; Shimizu, Masahiro; Sekine, Tomohito; Kumaki, Daisuke; Kurihara, Masato; Sakamoto, Masatomi; Tokito, Shizuo

    2013-05-01

    Fully solution-processed organic thin-film transistor (OTFT) devices have been fabricated with simple patterning process at a relatively low process temperature of 100 °C. In the patterning process, a hydrophobic amorphous fluoropolymer material, which was used as the gate dielectric layer and the underlying base layer, was treated with an oxygen plasma to selectively change its surface wetting properties from hydrophobic to hydrophilic. Silver source and drain electrodes were successfully formed in the treated areas with highly uniform line widths and without residues between the electrodes. Nonuniformities in the thickness of the silver electrodes originating from the “coffee-ring” effect were suppressed by optimizing the blend of solvents used with the silver nanoparticles, such that the printed electrodes are appropriate for bottom-gate OTFT devices. A fully solution-processed OTFT device using a polymer semiconductor material (PB16TTT) exhibited good electrical performance with no hysteresis in its transfer characteristics and with good linearity in its output characteristics. A relatively high carrier mobility of 0.14 cm2 V-1 s-1 and an on/off ratio of 1×105 were obtained with the fabricated TFT device.

  8. Highly selective determination of dopamine in the presence of ascorbic acid and serotonin at glassy carbon electrodes modified with carbon nanotubes dispersed in polyethylenimine.

    Science.gov (United States)

    Rodríguez, Marcela C; Rubianes, María D; Rivas, Gustavo A

    2008-11-01

    We report the highly selective and sensitive voltammetric dopamine quantification in the presence of ascorbic acid and serotonin by using glassy carbon electrodes modified with a dispersion of multi-wall carbon nanotubes (MWCNT) in polyethylenimine, PEI (GCE/MWCNT-PEI). The electrocatalytic activity of the MWCNT deposited on the glassy carbon electrode has allowed an important decrease in the overvoltages for the oxidation of ascorbic acid and dopamine, making possible a clear definition of dopamine, serotonin and ascorbic acid oxidation processes. The sensitivities for dopamine in the presence and absence of 1.0 mM ascorbic acid and serotonin were (2.18 +/- 0.03) x 10(5) microAM(-1) (r = 0.9998); and (2.10 +/- 0.07) x 10(5) miroAM(-1) (r=0.9985), respectively, demonstrating the excellent performance of the GCE/MWCNT-PEI. The detection limit for dopamine in the mixture was 9.2 x 10(-7) M. The R. S. D. for the determination of 50 microM dopamine using four different electrodes was 3.9% when modified with the same MWCNT/PEI dispersion, and 4.6% when using four different dispersions. The modified electrode has been successfully applied for recovery assays of dopamine in human blood serum. Therefore, the new sensor represents an interesting and promising alternative for the electrochemical quantification of neurotransmitters and other analytes of clinical interest.

  9. A solid-contact Pb2+-selective electrode using poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) as ion-to-electron transducer

    International Nuclear Information System (INIS)

    Yu Shunyang; Li Fuhai; Yin Tanji; Liu Yongming; Pan, Dawei; Qin Wei

    2011-01-01

    Highlights: → All reagents used for the electrodes preparation were commercially available. → The lower detection limit of the proposed electrode reached subnanomolar levels. → No water film was observed with conventional commercially available PVC ion-sensing membranes. → This research provides an excellent strategy for fabrication of robust polymeric ion sensors. - Abstract: In this work, a novel all-solid-state polymeric membrane Pb 2+ -selective electrode was developed by using for the first time poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) (MEH-PPV) as solid contact. To demonstrate the ion-to-electron transducing ability of MEH-PPV, chronopotentiometry and electrochemical impedance spectroscopy measurements were carried out. The proposed electrodes showed a Nernstian response of 29.1 mV decade -1 and a lower detection limit of subnanomolar level. No water film was observed with the conventional plasticized PVC membrane. This work demonstrates a new strategy for the fabrication of robust potentiometric ion sensors.

  10. Selecting polymers for two-phase partitioning bioreactors (TPPBs): Consideration of thermodynamic affinity, crystallinity, and glass transition temperature.

    Science.gov (United States)

    Bacon, Stuart L; Peterson, Eric C; Daugulis, Andrew J; Parent, J Scott

    2015-01-01

    Two-phase partitioning bioreactor technology involves the use of a secondary immiscible phase to lower the concentration of cytotoxic solutes in the fermentation broth to subinhibitory levels. Although polymeric absorbents have attracted recent interest due to their low cost and biocompatibility, material selection requires the consideration of properties beyond those of small molecule absorbents (i.e., immiscible organic solvents). These include a polymer's (1) thermodynamic affinity for the target compound, (2) degree of crystallinity (wc ), and (3) glass transition temperature (Tg ). We have examined the capability of three thermodynamic models to predict the partition coefficient (PC) for n-butyric acid, a fermentation product, in 15 polymers. Whereas PC predictions for amorphous materials had an average absolute deviation (AAD) of ≥16%, predictions for semicrystalline polymers were less accurate (AAD ≥ 30%). Prediction errors were associated with uncertainties in determining the degree of crystallinity within a polymer and the effect of absorbed water on n-butyric acid partitioning. Further complications were found to arise for semicrystalline polymers, wherein strongly interacting solutes increased the polymer's absorptive capacity by actually dissolving the crystalline fraction. Finally, we determined that diffusion limitations may occur for polymers operating near their Tg , and that the Tg can be reduced by plasticization by water and/or solute. This study has demonstrated the impact of basic material properties that affects the performance of polymers as sequestering phases in TPPBs, and reflects the additional complexity of polymers that must be taken into account in material selection. © 2015 American Institute of Chemical Engineers.

  11. Information-theoretical feature selection using data obtained by Scanning Electron Microscopy coupled with and Energy Dispersive X-ray spectrometer for the classification of glass traces

    International Nuclear Information System (INIS)

    Ramos, Daniel; Zadora, Grzegorz

    2011-01-01

    Highlights: → A selection of the best features for multivariate forensic glass classification using SEM-EDX was performed. → The feature selection process was carried out by means of an exhaustive search, with an Empirical Cross-Entropy objective function. → Results show remarkable accuracy of the best variables selected following the proposed procedure for the task of classifying glass fragments into windows or containers. - Abstract: In this work, a selection of the best features for multivariate forensic glass classification using Scanning Electron Microscopy coupled with an Energy Dispersive X-ray spectrometer (SEM-EDX) has been performed. This has been motivated by the fact that the databases available for forensic glass classification are sparse nowadays, and the acquisition of SEM-EDX data is both costly and time-consuming for forensic laboratories. The database used for this work consists of 278 glass objects for which 7 variables, based on their elemental compositions obtained with SEM-EDX, are available. Two categories are considered for the classification task, namely containers and car/building windows, both of them typical in forensic casework. A multivariate model is proposed for the computation of the likelihood ratios. The feature selection process is carried out by means of an exhaustive search, with an Empirical Cross-Entropy (ECE) objective function. The ECE metric takes into account not only the discriminating power of the model in use, but also its calibration, which indicates whether or not the likelihood ratios are interpretable in a probabilistic way. Thus, the proposed model is applied to all the 63 possible univariate, bivariate and trivariate combinations taken from the 7 variables in the database, and its performance is ranked by its ECE. Results show remarkable accuracy of the best variables selected following the proposed procedure for the task of classifying glass fragments into windows (from cars or buildings) or containers

  12. Synthesis of nano-sized arsenic-imprinted polymer and its use as As3+ selective ionophore in a potentiometric membrane electrode: Part 1

    International Nuclear Information System (INIS)

    Alizadeh, Taher; Rashedi, Mariyam

    2014-01-01

    Highlights: • The first arsenic cation-selective membrane electrode was introduced. • A novel procedure was introduced for the preparation of As-imprinted polymer. • It was found that arsenic is recognized by the IIP as As 3+ species. • Nernstian response of 20.4 mV decade −1 and DL of 0.5 μM was obtained. - Abstract: In this study, a new strategy was proposed for the preparation of As (III)-imprinted polymer by using arsenic (methacrylate) 3 as template. Precipitation polymerization was utilized to synthesize nano-sized As (III)-imprinted polymer. Methacrylic acid and ethylene glycol dimethacrylate were used as the functional monomer and cross-linking agent, respectively. In order to assembly functional monomers around As (III) ion, sodium arsenite and methacrylic acid were heated in the presence of hydroquinone, leading to arsenic (methacrylate) 3 . The nano-sized As (III) selective polymer was characterized by FT-IR and scanning electron microscopy techniques (SEM). It was demonstrated that arsenic was recognized as As 3+ by the selective cavities of the synthesized IIP. Based on the prepared polymer, the first arsenic cation selective membrane electrode was introduced. Membrane electrode was constructed by dispersion of As (III)-imprinted polymer nanoparticles in poly(vinyl chloride), plasticized with di-nonylphthalate. The IIP-modified electrode exhibited a Nernstian response (20.4 ± 0.5 mV decade −1 ) to arsenic ion over a wide concentration range (7.0 × 10 −7 to 1.0 × 10 −1 mol L −1 ) with a lower detection limit of 5.0 × 10 −7 mol L −1 . Unlike this, the non-imprinted polymer (NIP)-based membrane electrode was not sensitive to arsenic in aqueous solution. The selectivity of the developed sensor to As (III) was shown to be satisfactory. The sensor was used for arsenic determination in some real samples

  13. Synthesis of nano-sized arsenic-imprinted polymer and its use as As{sup 3+} selective ionophore in a potentiometric membrane electrode: Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Taher, E-mail: Alizadeh@uma.ac.ir; Rashedi, Mariyam

    2014-09-16

    Highlights: • The first arsenic cation-selective membrane electrode was introduced. • A novel procedure was introduced for the preparation of As-imprinted polymer. • It was found that arsenic is recognized by the IIP as As{sup 3+} species. • Nernstian response of 20.4 mV decade{sup −1} and DL of 0.5 μM was obtained. - Abstract: In this study, a new strategy was proposed for the preparation of As (III)-imprinted polymer by using arsenic (methacrylate){sub 3} as template. Precipitation polymerization was utilized to synthesize nano-sized As (III)-imprinted polymer. Methacrylic acid and ethylene glycol dimethacrylate were used as the functional monomer and cross-linking agent, respectively. In order to assembly functional monomers around As (III) ion, sodium arsenite and methacrylic acid were heated in the presence of hydroquinone, leading to arsenic (methacrylate){sub 3}. The nano-sized As (III) selective polymer was characterized by FT-IR and scanning electron microscopy techniques (SEM). It was demonstrated that arsenic was recognized as As{sup 3+} by the selective cavities of the synthesized IIP. Based on the prepared polymer, the first arsenic cation selective membrane electrode was introduced. Membrane electrode was constructed by dispersion of As (III)-imprinted polymer nanoparticles in poly(vinyl chloride), plasticized with di-nonylphthalate. The IIP-modified electrode exhibited a Nernstian response (20.4 ± 0.5 mV decade{sup −1}) to arsenic ion over a wide concentration range (7.0 × 10{sup −7} to 1.0 × 10{sup −1} mol L{sup −1}) with a lower detection limit of 5.0 × 10{sup −7} mol L{sup −1}. Unlike this, the non-imprinted polymer (NIP)-based membrane electrode was not sensitive to arsenic in aqueous solution. The selectivity of the developed sensor to As (III) was shown to be satisfactory. The sensor was used for arsenic determination in some real samples.

  14. Lap shear strength of selected adhesives (epoxy, varnish, B-stage glass cloth) in liquid nitrogen and at room temperature

    International Nuclear Information System (INIS)

    Froelich, K.J.; Fitzpatrick, C.M.

    1976-12-01

    The adhesives included several epoxy resins, a varnish, and a B-stage glass cloth (a partially cured resin in a fiberglass cloth matrix). Several parameters critical to bond strength were varied: adhesive and adherend differences, surface preparation, coupling agents, glass cloth, epoxy thickness, fillers, and bonding pressure and temperature. The highest lap shear strengths were obtained with the B-shear glass cloth at both liquid nitrogen and room temperatures with values of approximately 20 MPa (3000 psi) and approximately 25.5 MPa (3700 psi) respectively

  15. Preparation of PbO nanoparticles by microwave irradiation and their application to Pb(II)-selective electrode based on cellulose acetate

    International Nuclear Information System (INIS)

    Li Shengying; Yang Wu; Chen Miao; Gao Jinzhang; Kang Jingwan; Youli, Q.

    2005-01-01

    Nanosized lead oxide particles were prepared by thermal decomposition of lead hydroxycarbonate synthesized under microwave irradiation. Urea and lead nitrate were used as the starting materials. Microstructure and morphology of the products were investigated by means of XRD, AFM, TEM, and IR absorption spectra. The results indicated that well crystallized, finely dispersed and spherical α-PbO nanoparticles with a size of ca. 30 nm were obtained. Meanwhile, an orthogonal phase β-PbO with a size of ca. 38 nm was also obtained when the calcinations temperature was up to 600 deg. C. In addition, a Pb(II)-selective electrode based on cellulose acetate was prepared using nanosized α-PbO powders synthesized. The electrode exhibited a Nernstian slope of 29±1 mV per decade in a linear range of 2.5x10 -5 mol L -1 to 1.0x10 -1 mol L -1 for Pb 2+ ion. The detection limit of this electrode is down to 8.0x10 -6 mol L -1 . This sensor has a short response time of about 10 s and could be used in a pH range of 2.0-8.0. High selectivity was obtained over a wide variety of metal ions

  16. Baseline LAW Glass Formulation Testing

    International Nuclear Information System (INIS)

    Kruger, Albert A.; Mooers, Cavin; Bazemore, Gina; Pegg, Ian L.; Hight, Kenneth; Lai, Shan Tao; Buechele, Andrew; Rielley, Elizabeth; Gan, Hao; Muller, Isabelle S.; Cecil, Richard

    2013-01-01

    The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements

  17. Polymer Photovoltaic Cell Using TiO2/G-PEDOT Nanocomplex Film as Electrode

    Directory of Open Access Journals (Sweden)

    F. X. Xie

    2008-01-01

    Full Text Available Using TiO2/G-PEDOT (PEDOT/PSS doped with glycerol nanocomplex film as a substitute for metal electrode in organic photovoltaic cell is described. Indium tin oxide (ITO worked as cathode and TiO2/G-PEDOT nanocomplex works as anode. The thickness of TiO2 layer in nanocomplex greatly affects the act of this nonmetallic electrode of the device. To enhance its performance, this inverted organic photovoltaic cell uses another TiO2 layer as electron selective layer contacted to ITO coated glass substrates. All films made by solution processing techniques are coated on the transparent substrate (glass with a conducting film ITO. The efficiency of this solar cell is compared with the conventional device using Al as electrode.

  18. Role of the adsorbed oxygen species in the selective electrochemical reduction of CO{sub 2} to alcohols and carbonyls on copper electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Le Duff, Cecile S.; Lawrence, Matthew J.; Rodriguez, Paramaconi [School of Chemistry, University of Birmingham, Edgbaston (United Kingdom)

    2017-10-09

    The electrochemical reduction of CO{sub 2} into fuels has gained significant attention recently as source of renewable carbon-based fuels. The unique high selectivity of copper in the electrochemical reduction of CO{sub 2} to hydrocarbons has called much interest in discovering its mechanism. In order to provide significant information about the role of oxygen in the electrochemical reduction of CO{sub 2} on Cu electrodes, the conditions of the surface structure and the composition of the Cu single crystal electrodes were controlled over time. This was achieved using pulsed voltammetry, since the pulse sequence can be programmed to guarantee reproducible initial conditions for the reaction at every fraction of time and at a given frequency. In contrast to the selectivity of CO{sub 2} reduction using cyclic voltammetry and chronoamperometric methods, a large selection of oxygenated hydrocarbons was found under alternating voltage conditions. Product selectivity towards the formation of oxygenated hydrocarbon was associated to the coverage of oxygen species, which is surface-structure- and potential-dependent. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Role of the adsorbed oxygen species in the selective electrochemical reduction of CO_2 to alcohols and carbonyls on copper electrodes

    International Nuclear Information System (INIS)

    Le Duff, Cecile S.; Lawrence, Matthew J.; Rodriguez, Paramaconi

    2017-01-01

    The electrochemical reduction of CO_2 into fuels has gained significant attention recently as source of renewable carbon-based fuels. The unique high selectivity of copper in the electrochemical reduction of CO_2 to hydrocarbons has called much interest in discovering its mechanism. In order to provide significant information about the role of oxygen in the electrochemical reduction of CO_2 on Cu electrodes, the conditions of the surface structure and the composition of the Cu single crystal electrodes were controlled over time. This was achieved using pulsed voltammetry, since the pulse sequence can be programmed to guarantee reproducible initial conditions for the reaction at every fraction of time and at a given frequency. In contrast to the selectivity of CO_2 reduction using cyclic voltammetry and chronoamperometric methods, a large selection of oxygenated hydrocarbons was found under alternating voltage conditions. Product selectivity towards the formation of oxygenated hydrocarbon was associated to the coverage of oxygen species, which is surface-structure- and potential-dependent. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. A new strategy for the modification of a carbon paste electrode with carrageenan hydrogel for a sensitive and selective determination of arsenic in natural waters.

    Science.gov (United States)

    Núñez, Claudia; Arancibia, Verónica; Triviño, Juan José

    2018-09-01

    An adsorptive stripping voltammetric method for the determination of As(III) and As total in water samples using a carrageenan modified carbon paste electrode is presented for the first time (CAR-CPE). The modified electrode was prepared in different ways: by adding CAR in solid form or as a hydrogel together with graphite and paraffin, as well as adsorbing CAR by applying a potential on an unmodified carbon paste electrode. The best results were obtained when CAR was incorporated as hydrogel (HCAR-CPE). The selection of the ratio amounts for electrode preparation was carried out applying a multivariate experimental design. Variables like amount of graphite (U 1 ), HCAR (U 2 ) and paraffin (U 3 ) were optimized using a (2 K +2K+C) model. The results showed that the amount of HCAR was the most significant factor, and the adequate U 1 :U 2 :U 3 ratio to prepare the electrode was: 493 mg of graphite, 214 μL of paraffin and 134 μL of carrageenan as gel. The optimum parameters for the determination of As(III) were pH = 3.25 (0.01 mol L -1 H 3 PO 4 /H 2 PO 4 - solution); E acc = -0.50 V and t acc = 30 s. The electrode presents good linear behavior concentration range from 0.50 to 6.70 μg L -1 , with a limit of detection of 0.22 μg L -1 . The relative standard deviation was 5.0% at the 1.5 μg L -1 As(III) level (n = 16). The method was validated by quantifying As(III) in spiked tap water from laboratory (RE: 3.0%), and it was applied for the determination of As total in water samples from the Loa River (North of Chile) prior reduction of As(V) with Na 2 S 2 O 3 solution, obtaining 814.00 ± 0.03 μg L -1 . The results of the proposed method were compared with those obtained by adsorptive stripping voltammetry with HMDE and by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Functionalized-graphene modified graphite electrode for the selective determination of dopamine in presence of uric acid and ascorbic acid.

    Science.gov (United States)

    Mallesha, Malledevaru; Manjunatha, Revanasiddappa; Nethravathi, C; Suresh, Gurukar Shivappa; Rajamathi, Michael; Melo, Jose Savio; Venkatesha, Thimmappa Venkatarangaiah

    2011-06-01

    Graphene is chemically synthesized by solvothermal reduction of colloidal dispersions of graphite oxide. Graphite electrode is modified with functionalized-graphene for electrochemical applications. Electrochemical characterization of functionalized-graphene modified graphite electrode (FGGE) is carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The behavior of FGGE towards ascorbic acid (AA), dopamine (DA) and uric acid (UA) has been investigated by CV, differential pulse voltammetry (DPV) and chronoamperommetry (CA). The FGGE showed excellent catalytic activity towards electrochemical oxidation of AA, DA and UA compared to that of the bare graphite electrode. The electrochemical oxidation signals of AA, DA and UA are well separated into three distinct peaks with peak potential separation of 193mv, 172mv and 264mV between AA-DA, DA-UA and AA-UA respectively in CV studies and the corresponding peak potential separations in DPV mode are 204mv, 141mv and 345mv. The FGGE is successfully used for the simultaneous detection of AA, DA and UA in their ternary mixture and DA in serum and pharmaceutical samples. The excellent electrocatalytic behavior of FGGE may lead to new applications in electrochemical analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Selective formation of GaN-based nanorod heterostructures on soda-lime glass substrates by a local heating method

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Young Joon; Kim, Yong-Jin [Department of Materials Science and Engineering, POSTECH, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Jeon, Jong-Myeong; Kim, Miyoung; Choi, Jun Hee [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Baik, Chan Wook; Kim, Sun Il; Park, Sung Soo; Kim, Jong Min [Frontier Research Laboratory, Samsung Advanced Institute of Technology, PO Box 111, Kiheung 446-712 (Korea, Republic of); Yi, Gyu-Chul, E-mail: joonie.choi@samsung.com, E-mail: gcyi@snu.ac.kr [National Creative Research Initiative Center for Semiconductor Nanorods, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2011-05-20

    We report on the fabrication of high-quality GaN on soda-lime glass substrates, heretofore precluded by both the intolerance of soda-lime glass to the high temperatures required for III-nitride growth and the lack of an epitaxial relationship with amorphous glass. The difficulties were circumvented by heteroepitaxial coating of GaN on ZnO nanorods via a local microheating method. Metal-organic chemical vapor deposition of ZnO nanorods and GaN layers using the microheater arrays produced high-quality GaN/ZnO coaxial nanorod heterostructures at only the desired regions on the soda-lime glass substrates. High-resolution transmission electron microscopy examination of the coaxial nanorod heterostructures indicated the formation of an abrupt, semicoherent interface. Photoluminescence and cathodoluminescence spectroscopy was also applied to confirm the high optical quality of the coaxial nanorod heterostructures. Mg-doped GaN/ZnO coaxial nanorod heterostructure arrays, whose GaN shell layers were grown with various different magnesocene flow rates, were further investigated by using photoluminescence spectroscopy for the p-type doping characteristics. The suggested method for fabrication of III-nitrides on glass substrates signifies potentials for low-cost and large-size optoelectronic device applications.

  3. Selective formation of GaN-based nanorod heterostructures on soda-lime glass substrates by a local heating method.

    Science.gov (United States)

    Hong, Young Joon; Kim, Yong-Jin; Jeon, Jong-Myeong; Kim, Miyoung; Choi, Jun Hee; Baik, Chan Wook; Kim, Sun Il; Park, Sung Soo; Kim, Jong Min; Yi, Gyu-Chul

    2011-05-20

    We report on the fabrication of high-quality GaN on soda-lime glass substrates, heretofore precluded by both the intolerance of soda-lime glass to the high temperatures required for III-nitride growth and the lack of an epitaxial relationship with amorphous glass. The difficulties were circumvented by heteroepitaxial coating of GaN on ZnO nanorods via a local microheating method. Metal-organic chemical vapor deposition of ZnO nanorods and GaN layers using the microheater arrays produced high-quality GaN/ZnO coaxial nanorod heterostructures at only the desired regions on the soda-lime glass substrates. High-resolution transmission electron microscopy examination of the coaxial nanorod heterostructures indicated the formation of an abrupt, semicoherent interface. Photoluminescence and cathodoluminescence spectroscopy was also applied to confirm the high optical quality of the coaxial nanorod heterostructures. Mg-doped GaN/ZnO coaxial nanorod heterostructure arrays, whose GaN shell layers were grown with various different magnesocene flow rates, were further investigated by using photoluminescence spectroscopy for the p-type doping characteristics. The suggested method for fabrication of III-nitrides on glass substrates signifies potentials for low-cost and large-size optoelectronic device applications.

  4. Selective determination of four arsenic species in rice and water samples by modified graphite electrode-based electrolytic hydride generation coupled with atomic fluorescence spectrometry.

    Science.gov (United States)

    Yang, Xin-An; Lu, Xiao-Ping; Liu, Lin; Chi, Miao-Bin; Hu, Hui-Hui; Zhang, Wang-Bing

    2016-10-01

    This work describes a novel non-chromatographic approach for the accurate and selective determining As species by modified graphite electrode-based electrolytic hydride generation (EHG) for sample introduction coupled with atomic fluorescence spectrometry (AFS) detection. Two kinds of sulfydryl-containing modifiers, l-cysteine (Cys) and glutathione (GSH), are used to modify cathode. The EHG performance of As has been changed greatly at the modified cathode, which has never been reported. Arsenite [As(III)] on the GSH modified graphite electrode (GSH/GE)-based EHG can be selectively and quantitatively converted to AsH3 at applied current of 0.4A. As(III) and arsenate [As(V)] on the Cys modified graphite electrode (Cys/GE) EHG can be selectively and efficiently converted to arsine at applied current of 0.6A, whereas monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) do not form any or only less volatile hydrides under this condition. By changing the analytical conditions, we also have achieved the analysis of total As (tAs) and DMA. Under the optimal condition, the detection limits (3s) of As(III), iAs and tAs in aqueous solutions are 0.25μgL(-1), 0.22μgL(-1) and 0.10μgL(-1), respectively. The accuracy of the method is verified through the analysis of standard reference materials (SRM 1568a). Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Influence of phosphate buffer and proteins on the potentiometric response of a polymeric membrane-based solid-contact Pb(II) ion-selective electrode

    DEFF Research Database (Denmark)

    Joon, Narender Kumar; He, Ning; Wagner, Michal

    2017-01-01

    In this work, the influence of phosphate buffer and proteins on the potentiometric response of a polymeric membrane-based solid-contact Pb2+-selective electrode (Pb2+-ISE) was studied. The effects of bovine serum albumin (BSA) adsorption at the surface of the ion-selective membrane combined...... ions studied (Cu2+, Cd2+). Conditioning of the Pb2+-ISE in 0.01 mol dm–3 PBS resulted in a super-Nernstian response which was related to fixation/extraction of Pb2+ in the ion-selective membrane via precipitation of Pb3(PO4)2 by PO43– anions present in PBS. By conditioning of the Pb2+-ISE in 0.01 mol...

  6. A new cerium (III) ion selective electrode based on 2,9-dihydroxy-1,10-diphenoxy-4,7-dithia decane, a novel synthetic ligand

    Energy Technology Data Exchange (ETDEWEB)

    Rounaghi, Gholamhossein, E-mail: ghrounagh@yahoo.com [Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Zadeh Kakhki, Roya Mohammad; Sadeghian, Hamid [Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

    2011-11-30

    Highlights: > An ISE based on a new ionophore is used successfully to determine cerium (III) cation over the concentration range 1.0 x 10{sup -1}-2.1 x 10{sup -9} mol l{sup -1}. > It has a fast response time of 10 s. > It has comparatively good selectivities with respect to metal cations. > It can be used in a pH range of 5.0-8.0. > It also was used as an indicator electrode in potentiometric determination of F{sup -} ion in some real sample preparations. - Abstract: In the present study, a novel electrode based on 2,9-dihydroxy-1,10-diphenoxy-4,7-dithiadecane (DHDPDTD) that is selective to cerium (III) cations was evaluated electrochemically, and a Nerenstian slope (19.3 {+-} 1 mV decade{sup -1}) over a concentration range of 1.0 x 10{sup -8}-1.0 x 10{sup -1} M and a detection limit of 2.1 x 10{sup -9} M were observed. The proposed electrochemical sensor displayed a rapid response time of 10 s, improved selectivity towards Ce (III) cations in the presence of alkali, alkaline earth, transition and heavy metal cations, and could be used in a pH range of 5.0-8.0. Additionally, the proposed sensor was used as an indicator in the potentiometric titration of fluoride and the determination of F{sup -} ions in real samples.

  7. Highly sensitive and selective SO2 MOF sensor: the integration of MFM-300 MOF as a sensitive layer on a capacitive interdigitated electrode

    KAUST Repository

    Chernikova, Valeriya; Yassine, Omar; Shekhah, Osama; Eddaoudi, Mohamed; Salama, Khaled N.

    2018-01-01

    We report on the fabrication of an advanced chemical capacitive sensor for the detection of sulfur dioxide (SO2) at room temperature. The sensing layer based on an indium metal–organic framework (MOF), namely MFM-300, is coated solvothermally on a functionalized capacitive interdigitated electrode. The fabricated sensor exhibits significant detection sensitivity to SO2 at concentrations down to 75 ppb, with the lower detection limit estimated to be around 5 ppb. The MFM-300 MOF sensor demonstrates highly desirable detection selectivity towards SO2 vs. CH4, CO2, NO2 and H2, as well as an outstanding SO2 sensing stability.

  8. Highly sensitive and selective SO2 MOF sensor: the integration of MFM-300 MOF as a sensitive layer on a capacitive interdigitated electrode

    KAUST Repository

    Chernikova, Valeriya

    2018-03-05

    We report on the fabrication of an advanced chemical capacitive sensor for the detection of sulfur dioxide (SO2) at room temperature. The sensing layer based on an indium metal–organic framework (MOF), namely MFM-300, is coated solvothermally on a functionalized capacitive interdigitated electrode. The fabricated sensor exhibits significant detection sensitivity to SO2 at concentrations down to 75 ppb, with the lower detection limit estimated to be around 5 ppb. The MFM-300 MOF sensor demonstrates highly desirable detection selectivity towards SO2 vs. CH4, CO2, NO2 and H2, as well as an outstanding SO2 sensing stability.

  9. Carbon-Based Solid-State Calcium Ion-Selective Microelectrode and Scanning Electrochemical Microscopy: A Quantitative Study of pH-Dependent Release of Calcium Ions from Bioactive Glass.

    Science.gov (United States)

    Ummadi, Jyothir Ganesh; Downs, Corey J; Joshi, Vrushali S; Ferracane, Jack L; Koley, Dipankar

    2016-03-15

    Solid-state ion-selective electrodes are used as scanning electrochemical microscope (SECM) probes because of their inherent fast response time and ease of miniaturization. In this study, we report the development of a solid-state, low-poly(vinyl chloride), carbon-based calcium ion-selective microelectrode (Ca(2+)-ISME), 25 μm in diameter, capable of performing an amperometric approach curve and serving as a potentiometric sensor. The Ca(2+)-ISME has a broad linear response range of 5 μM to 200 mM with a near Nernstian slope of 28 mV/log[a(Ca(2+))]. The calculated detection limit for Ca(2+)-ISME is 1 μM. The selectivity coefficients of this Ca(2+)-ISME are log K(Ca(2+),A) = -5.88, -5.54, and -6.31 for Mg(2+), Na(+), and K(+), respectively. We used this new type of Ca(2+)-ISME as an SECM probe to quantitatively map the chemical microenvironment produced by a model substrate, bioactive glass (BAG). In acidic conditions (pH 4.5), BAG was found to increase the calcium ion concentration from 0.7 mM ([Ca(2+)] in artificial saliva) to 1.4 mM at 20 μm above the surface. In addition, a solid-state dual SECM pH probe was used to correlate the release of calcium ions with the change in local pH. Three-dimensional pH and calcium ion distribution mapping were also obtained by using these solid-state probes. The quantitative mapping of pH and Ca(2+) above the BAG elucidates the effectiveness of BAG in neutralizing and releasing calcium ions in acidic conditions.

  10. Dealing with correlated choices: how a spin-glass model can help political parties select their policies.

    Science.gov (United States)

    Moore, M A; Katzgraber, Helmut G

    2014-10-01

    Starting from preferences on N proposed policies obtained via questionnaires from a sample of the electorate, an Ising spin-glass model in a field can be constructed from which a political party could find the subset of the proposed policies which would maximize its appeal, form a coherent choice in the eyes of the electorate, and have maximum overlap with the party's existing policies. We illustrate the application of the procedure by simulations of a spin glass in a random field on scale-free networks.

  11. A novel highly selective and sensitive detection of serotonin based on Ag/polypyrrole/Cu2O nanocomposite modified glassy carbon electrode.

    Science.gov (United States)

    Selvarajan, S; Suganthi, A; Rajarajan, M

    2018-06-01

    A silver/polypyrrole/copper oxide (Ag/PPy/Cu 2 O) ternary nanocomposite was prepared by sonochemical and oxidative polymerization simple way, in which Cu 2 O was decorated with Ag nanoparticles, and covered by polyprrole (PPy) layer. The as prepared materials was characterized by UV-vis-spectroscopy (UV-vis), FT-IR, X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM) with EDX, high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Sensing of serotonin (5HT) was evaluated electrocatalyst using polypyrrole/glassy carbon electrode (PPy/GCE), polypyrrole/copper oxide/glassy carbon electrode (PPy/Cu 2 O/GCE) and silver/polypyrrole/copper oxide/glassy carbon electrode (Ag/PPy/Cu 2 O/GCE). The Ag/PPy/Cu 2 O/GCE was electrochemically treated in 0.1MPBS solution through cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The peak current response increases linearly with 5-HT concentration from 0.01 to 250 µmol L -1 and the detection limit was found to be 0.0124 μmol L -1 . It exhibits high electrocatalytic activity, satisfactory repeatability, stability, fast response and good selectivity against potentially interfering species, which suggests its potential in the development of sensitive, selective, easy-operation and low-cost serotonin sensor for practical routine analyses. The proposed method is potential to expand the possible applied range of the nanocomposite material for detection of various concerned electro active substances. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Radionuclide Incorporation in Secondary Crystalline Minerals Resulting from Chemical Weathering of Selected Waste Glasses: Progress Report: Task kd.5b

    International Nuclear Information System (INIS)

    Mattigod, Shas V.; Serne, R. Jeffrey; Legore, Virginia L.; Parker, Kent E.; Orr, Robert D.; McCready, David E.; )

    2003-01-01

    Experiments were conducted by Pacific Northwest National Laboratory to evaluate potential incorporation of radionuclides in secondary mineral phases that form from weathering vitrified nuclear waste glasses. These experiments were conducted as part of the Immobilized Low-Activity Waste-Performance Assessment (ILAW-PA) to generate data on radionuclide mobilization and transport in a near-field environment of disposed vitrified wastes. The results of these experiments demonstrated that radionuclide sequestration can be significantly enhanced by promoting the formation of cage structured minerals such as sodalite from weathering glasses. These results have important implications regarding radionuclide sequestration/mobilization aspects that are not currently accounted for in the ILAW PA. Additional studies are required to confirm the results and to develop an improved understanding of the mechanisms of sequestration of radionuclides into the secondary and tertiary weathering products o f the ILAW glass to help refine how contaminants are released from the near-field disposal region out into the accessible environment. Of particular interest is to determine whether the contaminants remain sequestered in the glass weathering products for hundreds to thousands of years. If the sequestration can be shown to continue for long periods, another immobilization process can be added to the PA analysis and predicted risks should be lower than past predictions

  13. Politics and the Glass Cliff: Evidence that Women Are Preferentially Selected to Contest Hard-to-Win Seats

    Science.gov (United States)

    Ryan, Michelle K.; Haslam, S. Alexander; Kulich, Clara

    2010-01-01

    Recent archival and experimental research has revealed that women are more likely than men to be appointed to leadership positions when an organization is in crisis. As a result, women often confront a "glass cliff" in which their position as leader is precarious. Our first archival study examined the 2005 UK general election and found…

  14. A highly selective electrochemical sensor based on molecularly imprinted polypyrrole-modified gold electrode for the determination of glyphosate in cucumber and tap water.

    Science.gov (United States)

    Zhang, Chao; She, Yongxin; Li, Tengfei; Zhao, Fengnian; Jin, Maojun; Guo, Yirong; Zheng, Lufei; Wang, Shanshan; Jin, Fen; Shao, Hua; Liu, Haijin; Wang, Jing

    2017-12-01

    An electrochemical sensor based on molecularly imprinted polypyrrole (MIPPy) was developed for selective and sensitive detection of the herbicide glyphosate (Gly) in cucumber and tap water samples. The sensor was prepared via synthesis of molecularly imprinted polymers on a gold electrode in the presence of Gly as the template molecule and pyrrole as the functional monomer by cyclic voltammetry (CV). The sensor preparation conditions including the ratio of template to functional monomers, number of CV cycles in the electropolymerization process, the method of template removal, incubation time, and pH were optimized. Under the optimal experimental conditions, the DPV peak currents of hexacyanoferrate/hexacyanoferrite changed linearly with Gly concentration in the range from 5 to 800 ng mL -1 , with a detection limit of 0.27 ng mL -1 (S/N = 3). The sensor was used to detect the concentration of Gly in cucumber and tap water samples, with recoveries ranging from 72.70 to 98.96%. The proposed sensor showed excellent selectivity, good stability and reversibility, and could detect the Gly in real samples rapidly and sensitively. Graphical abstract Schematic illustration of the experimental procedure to detect Gly using the MIPPy electrode.

  15. Spontaneous and Selective Nanowelding of Silver Nanowires by Electrochemical Ostwald Ripening and High Electrostatic Potential at the Junctions for High-Performance Stretchable Transparent Electrodes.

    Science.gov (United States)

    Lee, Hyo-Ju; Oh, Semi; Cho, Ki-Yeop; Jeong, Woo-Lim; Lee, Dong-Seon; Park, Seong-Ju

    2018-04-25

    Metal nanowires have been gaining increasing attention as the most promising stretchable transparent electrodes for emerging field of stretchable optoelectronic devices. Nanowelding technology is a major challenge in the fabrication of metal nanowire networks because the optoelectronic performances of metal nanowire networks are mostly limited by the high junction resistance between nanowires. We demonstrate the spontaneous and selective welding of Ag nanowires (AgNWs) by Ag solders via an electrochemical Ostwald ripening process and high electrostatic potential at the junctions of AgNWs. The AgNWs were welded by depositing Ag nanoparticles (AgNPs) on the conducting substrate and then exposing them to water at room temperature. The AgNPs were spontaneously dissolved in water to form Ag + ions, which were then reduced to single-crystal Ag solders selectively at the junctions of the AgNWs. Hence, the welded AgNWs showed higher optoelectronic and stretchable performance compared to that of as-formed AgNWs. These results indicate that electrochemical Ostwald ripening-based welding can be used as a promising method for high-performance metal nanowire electrodes in various next-generation devices such as stretchable solar cells, stretchable displays, organic light-emitting diodes, and skin sensors.

  16. Ion selective electrode for cesium based on 5-(4'-nitrophenylazo)25,27-bis(2-propyloxy)26,28-dihydroxycalix[4]arene.

    Science.gov (United States)

    Ramanjaneyulu, P S; Singh, Parminder; Sayi, Y S; Chawla, H M; Ramakumar, K L

    2010-03-15

    A polyvinylchloride (PVC) based liquid membrane ion selective electrode (ISE) for cesium was fabricated with 5-(4'-nitrophenylazo)25,27-bis(2-propyloxy)26,28-dihydroxycalix[4]arene as ionophore. Different membrane constituents were investigated to realise optimum performance of the ISE developed. Of the four plasticizers and two ion additives studied, the best response was observed with membrane having 2-nitro phenyl octyl ether (oNPOE) as plasticizer and potassium tetrakis (perchloro phenyl) borate (KTpClPB) as ion additive. Linear response over concentration range of 10(-5)-10(-1)M CsCl was obtained. The Nernstian slope of the response was 56 mV per decade for Cs with a response time less than 20s. Matched potential method has been applied to find out the selectivity for Cs over several ions like Rb(+), K(+), Na(+), NH(4)(+), Sr(2+), Ba(2+), Ca(2+), Mg(2+), Cu(2+), Pb(2+), Zn(2+), Ni(2+) and Ce(3+). The response of ISE for Cs(+) was fairly constant over the pH range of 3-11. The lifetime of the electrode is 9 months which is the longest life for any membrane-based Cs-ISE so far developed. The concentration of cesium in two simulated high level active waste streams was determined and results agreed well with those obtained independently employing atomic absorption spectrometry. (c) 2009 Elsevier B.V. All rights reserved.

  17. Impedance spectral fingerprint of E. coli cells on interdigitated electrodes: A new approach for label free and selective detection

    Directory of Open Access Journals (Sweden)

    Maria Mallén-Alberdi

    2016-03-01

    Full Text Available Impedance-based biosensors for bacterial detection offer a rapid and cost-effective alternative to conventional techniques that are time-consuming and require specialized equipment and trained users. In this work, a new bacteria detection scheme is presented based on impedance measurements with antibody-modified polysilicon interdigitated electrodes (3 μm pitch, IDEs. The detection approach was carried out taking advantage of the E. coli structure which, in electrical terms, is constituted by two insulating cell membranes that separate a conductive cytoplasmatic medium and a more conductive periplasm. Impedance detection of bacteria is usually analyzed using electrical equivalent circuit models that show limitations for the interpretation of such complex cell structure. Here, a differential impedance spectrum representation is used to study the unique fingerprint that arises when bacteria attach to the surface of IDEs. That fingerprint shows the dual electrical behavior, insulating and conductive, at different frequency ranges. In parallel, finite-element simulations of this system using a three-shell bacteria model are performed to explain such phenomena. Overall, a new approach to detect bacteria is proposed that also enables to differentiate viable bacteria from other components non-specifically attached to the IDE surface by just detecting their spectral fingerprints. Keywords: Impedance spectroscopy, Bacterial detection, Interdigitated electrodes, Label-free detection, Immuno-detection, E. coli O157:H7

  18. Using gold nanostars modified pencil graphite electrode as a novel substrate for design a sensitive and selective Dopamine aptasensor

    Energy Technology Data Exchange (ETDEWEB)

    Talemi, Rasoul Pourtaghavi, E-mail: rasoulpourtaghavi@gmail.com [Faculty of Chemistry, Kharazmi University, Tehran (Iran, Islamic Republic of); Mousavi, Seyed Mehdi [Faculty of Chemistry, Kharazmi University, Tehran (Iran, Islamic Republic of); Afruzi, Hossein [Department of Chemistry, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of)

    2017-04-01

    For the first time, gold nanostars (GNS) were applied for electrostatic and covalent immobilizing a thiol modified Dopamine aptamer on the pencil graphite electrode and signal amplification. Dopamine aptamer was immobilized on the gold nanostars through electrostatic interaction between negatively charged phosphate groups of aptamer and positively charged gold nanostars and Au−S well known covalent interaction. In the presence of Dopamine in the test solution, the charge transfer resistance (R{sub CT}) on the electrode surface increased with the increase of the Dopamine concentration due to specific interaction between Dopamine aptamer and Dopamine molecules, which made a barrier for electrons and inhibited the electron-transfer. So, the proposed approach showed a high sensitivity and a wide linearity to Dopamine in the range from 1.0 (± 0.1) to 100.0 (± 0.3) ng L{sup −1} (ppt) with detection and quantification limits of 0.29 (± 0.10) and 0.90 (± 0.08) ng L{sup −1} (ppt), respectively. Finally, the sensor was successfully used for determination of Dopamine in biological (human blood plasma and urine) samples. The results open up the path for manufacturing cost effective aptasensors for other biomedical applications. - Highlights: • A novel impedimetric aptasensor was prepared for dopamine ultra-trace determination. • Gold nanostar used for electrostatic and covalent immobilization of a thiolated dopamine aptamer. • The proposed aptasensor had high sensitivity, specificity, and regeneration ability.

  19. Area-Selective ZnO Thin Film Deposition on Variable Microgap Electrodes and Their Impact on UV Sensing

    Directory of Open Access Journals (Sweden)

    Q. Humayun

    2013-01-01

    Full Text Available ZnO thin films were deposited on patterned gold electrodes using the sol-gel spin coating technique. Conventional photolithography process was used to obtain the variable microgaps of 30 and 43 μm in butterfly topology by using zero-gap chrome mask. The structural, morphological, and electrical properties of the deposited thin films were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, and Keithley SourceMeter, respectively. The current-voltage (I-V characterization was performed to investigate the effect of UV light on the fabricated devices. The ZnO fabricated sensors showed a photo to dark current (Iph/Id ratios of 6.26 for 30 μm and 5.28 for 43 μm gap electrodes spacing, respectively. Dynamic responses of both fabricated sensors were observed till 1V with good reproducibility. At the applied voltage of 1 V, the response time was observed to be 4.817 s and 3.704 s while the recovery time was observed to be 0.3738 s and 0.2891 s for 30 and 43 μm gaps, respectively. The signal detection at low operating voltages suggested that the fabricated sensors could be used for miniaturized devices with low power consumption.

  20. Using gold nanostars modified pencil graphite electrode as a novel substrate for design a sensitive and selective Dopamine aptasensor

    International Nuclear Information System (INIS)

    Talemi, Rasoul Pourtaghavi; Mousavi, Seyed Mehdi; Afruzi, Hossein

    2017-01-01

    For the first time, gold nanostars (GNS) were applied for electrostatic and covalent immobilizing a thiol modified Dopamine aptamer on the pencil graphite electrode and signal amplification. Dopamine aptamer was immobilized on the gold nanostars through electrostatic interaction between negatively charged phosphate groups of aptamer and positively charged gold nanostars and Au−S well known covalent interaction. In the presence of Dopamine in the test solution, the charge transfer resistance (R CT ) on the electrode surface increased with the increase of the Dopamine concentration due to specific interaction between Dopamine aptamer and Dopamine molecules, which made a barrier for electrons and inhibited the electron-transfer. So, the proposed approach showed a high sensitivity and a wide linearity to Dopamine in the range from 1.0 (± 0.1) to 100.0 (± 0.3) ng L −1 (ppt) with detection and quantification limits of 0.29 (± 0.10) and 0.90 (± 0.08) ng L −1 (ppt), respectively. Finally, the sensor was successfully used for determination of Dopamine in biological (human blood plasma and urine) samples. The results open up the path for manufacturing cost effective aptasensors for other biomedical applications. - Highlights: • A novel impedimetric aptasensor was prepared for dopamine ultra-trace determination. • Gold nanostar used for electrostatic and covalent immobilization of a thiolated dopamine aptamer. • The proposed aptasensor had high sensitivity, specificity, and regeneration ability.

  1. Low-Li2O Frits: Selecting Glasses that Support the Melt Rate Studies and Challenge the Current Durability Model

    International Nuclear Information System (INIS)

    Peeler, D. K.; Edwards, T. B.

    2005-01-01

    During the progressive development of the cold cap model (as it applies to a potential melt rate predictive tool), the formation of an Al-Li-silicate phase was identified as an intermediate reaction phase that could possibly hinder melt rate for SB4. To test this theory, six glasses were designed (using Frit 320's composition as the baseline) to maintain a constant 20 wt% sum of alkali content (in frit) by varying Na 2 O to Li 2 O ratios. The Li 2 O concentration ranged from 8 wt% down to 0% in either 2% or 1% increments with the differences being accounted for by an increase in Na 2 O concentration. Although the primary objective of the ''lower Li 2 O'' frits was to evaluate the potential for melt rate improvements, assessments of durability (as measured by the Product Consistency Test (PCT)) were also performed. The results suggest that durable glasses can be produced with these ''lower Li 2 O'' frits should it be necessary to pursue this option for improving melt rate. In addition to the series of glasses to support melt rate assessments, a series of frits were also developed to challenge the current durability model based on the limits proposed by Edwards et al. (2004). Although the ''new'' limits allow access into compositional regions of interest (i.e., higher alkali systems) which can improve melt rate and/or waste loading, there may still be ''additional'' conservatism. In this report, two series of glasses were developed to challenge the ''new'' durability limits for the SB4 system. In the first series, the total alkali of the Frit 320-based glasses (designed to support the melt rate program) was increased from 20 wt% to 21 wt% (in the frit), but the series also evaluated the possible impact of various Na 2 O and Li 2 O mass ratio differences. The second series pushed the alkali limit in the frit even further with frits containing either 22 or 24 wt% total alkali as well as various Na 2 O and Li 2 O mass ratios. The results of the PCT evaluation indicated

  2. Structural in situ study of the thermal behavior of manganese dioxide materials: toward selected electrode materials for supercapacitors.

    Science.gov (United States)

    Ghodbane, Ouassim; Pascal, Jean-Louis; Fraisse, Bernard; Favier, Frédéric

    2010-12-01

    The thermal behavior of a series of MnO2 materials was investigated toward MnO2 microstructures under inert atmospheres. The byproduct formed during MnO2 heat treatments from the room temperature to 800 °C were characterized by in situ X-ray diffraction analyses. It was found that annealing spinel and ramsdellite phases caused the formation of MnO2 pyrolusite at 200 °C, Mn2O3, at 400 °C, and then Mn3O4 at higher temperatures. In the case of cryptomelane and birnessite phases, the heating process resulted in the formation of K0.51Mn0.93O2 at 600 °C, while Mn3O4 was also formed and still present up to 800 °C. Heat-treating Ni-todorokite and OMS-5 up to about 450 °C led to the formation of NiMn2O4 and NaxMnO2, respectively, and again Mn3O4 at higher temperatures. All of these structural transformations were correlated to resulting weight losses of MnO2 powders, measured by thermogravimetric analyses, during the heating process. Cyclic voltammetry measurements were performed in the presence of 0.5 M K2SO4 aqueous solution for annealed cryptomelane, K0.51Mn0.93O2, and Mn3O4-based electrodes. It was found that MnO2 cryptomelane is electrochemically stable upon heating. The long-term charge/discharge voltammetric cycling revealed that the specific capacitance of Mn3O4-based electrode is significantly improved from 14 F·g(-1) (after 20 cycles) to 123 F·g(-1) (after 500 cycles).

  3. Electrochromic Glasses.

    Science.gov (United States)

    1980-07-31

    this glass and that dipole-dipole correlations contribute to the "ferroelectric-like" character of this amorphous system. The TeO2 -W03 glasses can only...shows the dielectric constant and Fig. I(b) glass from pure TeO2 ot pure WO. In addition, glass the tan 8 of the WO glass as a function of temperature... glasses containing WO, in various glass forming nitworks of LifO-B1O0, Na:O-BzO,, and TeO2 were prepared from reagent grade oxides at 800 C - 9SO C in

  4. Highly conductive cathode materials for Li-ion batteries prepared by thermal nanocrystallization of selected oxide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pietrzak, T.K.; Wasiucionek, M.; Michalski, P.P.; Kaleta, A.; Garbarczyk, J.E., E-mail: garbar@if.pw.edu.pl

    2016-11-15

    Glassy analogs of two important cathode materials for Li-ion cells: V{sub 2}O{sub 5} and phosphoolivine LiFePO{sub 4} were heat-treated in order to prepare nanocrystallized materials with high electronic conductivity of up to 7 × 10{sup −2} S cm{sup −1} and ca 7 × 10{sup −3} S cm{sup −1} at 25 °C, respectively. There is a clear correlation between the crystallization phenomena and the increase in the electrical conductivity for both groups of glasses. Electrochemical tests of heat-treated glasses of the V{sub 2}O{sub 5}–P{sub 2}O{sub 5} system, used as cathodes in lithium cells confirm their good gravimetric capacity and reversibility. Heat-treatment of glasses of the Li{sub 2}O–FeO–V{sub 2}O{sub 5}–P{sub 2}O{sub 5} system also leads to a high increase in the conductivity and to formation of nanocrystalline grains in the glassy matrix, evidenced by HR-TEM images. The temperature dependence of the conductivity of these materials follows the Arrhenius formula. The presented results indicate that the overall increase in conductivity in nanocrystallized materials is due to good charge transport properties of their interfacial regions.

  5. A fast response hafnium selective polymeric membrane electrode based on N,N'-bis(α-methyl-salicylidene)-dipropylenetriamine as a neutral carrier

    International Nuclear Information System (INIS)

    Rezaei, B.; Meghdadi, S.; Zarandi, R. Fazel

    2008-01-01

    In this study a new hafnium selective sensor was fabricated from polyvinylchloride (PVC) matrix membrane containing neutral carrier N,N'-bis(α-methyl-salicylidene)-dipropylenetriamine (Mesaldpt) as a new ionophore, sodium tetraphenyl borate (NaTPB) as anionic discriminator and dioctyl phthalate (DOP) as plasticizing solvent mediator in tetrahydrofuran solvent. The electrode exhibits Nernstian response for Hf 4+ (Hafnium(IV)) over a wide concentration range (2.0 x 10 -7 to 1.0 x 10 -1 M) with the determination coefficient of 0.9966 and slope of 15.1 ± 0.1 mV decades -1 . The limit of detection is 1.9 x 10 -7 M. The electrode has a fast response time of 18 s and a working pH range of 4-8. The proposed membrane shows excellent discriminating ability towards Hf 4+ ion with regard to several alkali, alkaline earth transition and heavy metal ions. It can be used over a period of 1.5 months with good reproducibility. It is successfully applied for direct determination of Hf 4+ in solutions by standard addition method for real sample analysis

  6. A fast response hafnium selective polymeric membrane electrode based on N,N'-bis({alpha}-methyl-salicylidene)-dipropylenetriamine as a neutral carrier

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, B. [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)], E-mail: rezaei@cc.iut.ac.ir; Meghdadi, S.; Zarandi, R. Fazel [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2008-08-30

    In this study a new hafnium selective sensor was fabricated from polyvinylchloride (PVC) matrix membrane containing neutral carrier N,N'-bis({alpha}-methyl-salicylidene)-dipropylenetriamine (Mesaldpt) as a new ionophore, sodium tetraphenyl borate (NaTPB) as anionic discriminator and dioctyl phthalate (DOP) as plasticizing solvent mediator in tetrahydrofuran solvent. The electrode exhibits Nernstian response for Hf{sup 4+} (Hafnium(IV)) over a wide concentration range (2.0 x 10{sup -7} to 1.0 x 10{sup -1} M) with the determination coefficient of 0.9966 and slope of 15.1 {+-} 0.1 mV decades{sup -1}. The limit of detection is 1.9 x 10{sup -7} M. The electrode has a fast response time of 18 s and a working pH range of 4-8. The proposed membrane shows excellent discriminating ability towards Hf{sup 4+} ion with regard to several alkali, alkaline earth transition and heavy metal ions. It can be used over a period of 1.5 months with good reproducibility. It is successfully applied for direct determination of Hf{sup 4+} in solutions by standard addition method for real sample analysis.

  7. Selective hydrogen detection at high temperature by using yttria-stabilized zirconia-based sensor with coupled metal-oxide-based sensing electrodes

    International Nuclear Information System (INIS)

    Yamaguchi, Mami; Anggraini, Sri Ayu; Fujio, Yuki; Breedon, Michael; Plashnitsa, Vladimir V.; Miura, Norio

    2012-01-01

    A selective and sensitive hydrogen (H 2 ) sensor capable of working at a high operating temperature was developed by using a pair of metal-oxide-based SEs formed on a yttria-stabilized zirconia (YSZ) tube, operating as a mixed-potential type sensor. The utilization of SnO 2 (+30 wt.% YSZ) electrode together with NiO-TiO 2 electrode configured as a combined-type sensor, successfully diminished the response of the examined interfering gases (especially propene), while maintaining high response toward H 2 at an operating temperature of 600 °C under humid operating conditions. The developed sensor exhibited quick response to 100 ppm H 2 , as the 90% response time was observed to be 9 s. The sensing performance of the combined-type sensor was barely affected by changes in water vapor concentration within the range of 1–4 vol.%, suggesting the resilience of the sensor to function in realistic working conditions. This sensor exhibited a linear relationship between sensitivity and H 2 concentration on a logarithmic scale.

  8. Potentiometric flow injection system for determination of reductants using a polymeric membrane permanganate ion-selective electrode based on current-controlled reagent delivery.

    Science.gov (United States)

    Song, Wenjing; Ding, Jiawang; Liang, Rongning; Qin, Wei

    2011-10-17

    A polymeric membrane permanganate-selective electrode has been developed as a current-controlled reagent release system for potentiometric detection of reductants in flow injection analysis. By applying an external current, diffusion of permanganate ions across the polymeric membrane can be controlled precisely. The permanganate ions released at the sample-membrane interface from the inner filling solution of the electrode are consumed by reaction with a reductant in the sample solution thus changing the measured membrane potential, by which the reductant can be sensed potentiometrically. Ascorbate, dopamine and norepinephrine have been employed as the model reductants. Under the optimized conditions, the potential peak heights are proportional to the reductant concentrations in the ranges of 1.0×10(-5) to 2.5×10(-7)M for ascorbate, of 1.0×10(-5) to 5.0×10(-7)M for dopamine, and of 1.0×10(-5) to 5.0×10(-7)M for norepinephrine, respectively with the corresponding detection limits of 7.8×10(-8), 1.0×10(-7) and 1.0×10(-7)M. The proposed system has been successfully applied to the determination of reductants in pharmaceutical preparations and vegetables, and the results agree well with those of iodimetric analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. An Integrated Glucose Sensor with an All-Solid-State Sodium Ion-Selective Electrode for a Minimally Invasive Glucose Monitoring System

    Directory of Open Access Journals (Sweden)

    Junko Kojima

    2015-06-01

    Full Text Available We developed a minimally invasive glucose monitoring system that uses a microneedle to permeate the skin surface and a small hydrogel to accumulate interstitial fluid glucose. The measurement of glucose and sodium ion levels in the hydrogel is required for estimating glucose levels in blood; therefore, we developed a small, enzyme-fixed glucose sensor with a high-selectivity, all-solid-state, sodium ion-selective electrode (ISE integrated into its design. The glucose sensor immobilized glucose oxidase showed a good correlation between the glucose levels in the hydrogels and the reference glucose levels (r > 0.99, and exhibited a good precision (coefficient of variation = 2.9%, 0.6 mg/dL. In the design of the sodium ISEs, we used the insertion material Na0.33MnO2 as the inner contact layer and DD16C5 exhibiting high Na+/K+ selectivity as the ionophore. The developed sodium ISE exhibited high selectivity (\\( \\log \\,k^{pot}_{Na,K} = -2.8\\ and good potential stability. The sodium ISE could measure 0.4 mM (10−3.4 M sodium ion levels in the hydrogels containing 268 mM (10−0.57 M KCl. The small integrated sensor (ϕ < 10 mm detected glucose and sodium ions in hydrogels simultaneously within 1 min, and it exhibited sufficient performance for use as a minimally invasive glucose monitoring system.

  10. The Graphene/l-Cysteine/Gold-Modified Electrode for the Differential Pulse Stripping Voltammetry Detection of Trace Levels of Cadmium

    Directory of Open Access Journals (Sweden)

    Yu Song

    2016-06-01

    Full Text Available Cadmium(II is a common water pollutant with high toxicity. It is of significant importance for detecting aqueous contaminants accurately, as these contaminants are harmful to human health and environment. This paper describes the fabrication, characterization, and application of an environment-friendly graphene (Gr/l-cysteine/gold electrode to detect trace levels of cadmium (Cd by differential pulse stripping voltammetry (DPSV. The influence of hydrogen overflow was decreased and the current response was enhanced because the modified graphene extended the potential range of the electrode. The Gr/l-cysteine/gold electrode showed high electrochemical conductivity, producing a marked increase in anodic peak currents (vs. the glass carbon electrode (GCE and boron-doped diamond (BDD electrode. The calculated detection limits are 1.15, 0.30, and 1.42 µg/L, and the sensitivities go up to 0.18, 21.69, and 152.0 nA·mm−2·µg−1·L for, respectively, the BDD electrode, the GCE, and the Gr/l-cysteine/gold electrode. It was shown that the Gr/l-cysteine/gold-modified electrode is an effective means for obtaining highly selective and sensitive electrodes to detect trace levels of cadmium.

  11. Straightforward grafting approach for cyclam-functionalized screen-printed electrodes for selective Cu(II) determination

    International Nuclear Information System (INIS)

    Jasmin, Jean-Philippe; Ouhenia-Ouadahi, Karima; Miserque, Frédéric; Dumas, Eddy; Cannizzo, Caroline; Chaussé, Annie

    2016-01-01

    We report in this paper an original way to covalently bind the macrocyclic ligand, 1,4,8,11-tetraazacyclotetradecane (cyclam), through diazonium salt chemistry, on the surface of carbon screen-printed electrodes (SPEs). The in situ synthesis of the diazonium salt obtained from the amine precursor derived from the cyclam and its electrografting are described. X-ray Photoelectron Spectroscopy was used to characterize this functionalized surface. Owing to the strong cyclam–Cu(II) affinity, the so called SPE-cyclam can be used as electrochemical sensors for Cu(II) determination at trace levels. The influence of electroanalysis parameters such as the accumulation time and the pH of the medium were investigated. An interference study was carried out with numerous metallic cations and few interference was found for Cu(II) quantification. The described method provided a limit of detection and a limit of quantification of 1.3 × 10"−"8 M and 4.0 × 10"−"8 M, respectively. Interference study and performances show that SPE-cyclam could be considered as efficient sensors for environmental analysis.

  12. Direct Electrodeposition of Gold Nanoparticles on Glassy Carbon Electrode for Selective Determination Catechol in the Presence of Hydroquinone.

    Science.gov (United States)

    Jayakumar, C; Magdalane, C Maria; Kaviyarasu, K; Kulandainathan, M Anbu; Jeyaraj, Boniface; Maaza, M

    2018-07-01

    A simple and reliable voltammetric sensor for simultaneous determination of Catechol (CT) and Hydroquinone (HQ) was developed by electrodepositing the gold nanoparticles on the surface of the Glassy Carbon Electrode (GCE). The cyclic voltammograms in a mixed solution of CT and HQ have shown that the oxidation peaks become well resolved and were separated by 110 mV, although the bare GCE gave a single broad oxidation peak. Moreover, the oxidation peak currents of both CT and HQ were remarkably increased three times in comparison with the bare GCE. This makes gold nanoparticles deposited GCE a suitable candidate for the determination of these isomers. In the presence of 1 mM HQ isomer, the oxidation peak currents of differential pulse voltammograms are proportional to the concentration of CT in the range of 21 μM to 323 μM with limit of detection 3.0 μM (S/N = 3). The proposed sensor has some important advantages such as low cost, ease of preparation, good stability and high reproducibility.

  13. Potentiometric titration of polyhexamethylene biguanide hydrochloride with potassium poly(vinyl sulfate) solution using a cationic surfactant-selective electrode.

    Science.gov (United States)

    Masadome, Takashi; Yamagishi, Yuichi; Takano, Masaki; Hattori, Toshiaki

    2008-03-01

    A potentiometric titration method using a cationic surfactant as an indicator cation and a plasticized poly(vinyl chloride) membrane electrode sensitive to the cationic surfactant is proposed for the determination of polyhexamethylene biguanide hydrochloride (PHMB-HCl), which is a cationic polyelectrolyte. A sample solution of PHMB-HCl containing an indicator cation (hexadecyltrimethylammonium ion, HTA) was titrated with a standard solution of an anionic polyelectrolyte, potassium poly(vinyl sulfate) (PVSK). The end-point was detected as a sharp potential change due to an abrupt decrease in the concentration of the indicator cation, HTA, which is caused by its association with PVSK. The effects of the concentrations of HTA ion and coexisting electrolytes in the sample solution on the degree of the potential change at the end-point were examined. A linear relationship between the concentration of PHMB-HCl and the end-point volume of the titrant exists in the concentration range from 2.0 x 10(-5) to 4.0 x 10(-4) M in the case that the concentration of HTA is 1.0 x 10(-5) M, and that from 1.0 x 10(-6) to 1.2 x 10(-5) M in the case that the concentration of HTA is 5.0 x 10(-6) M, respectively. The proposed method was applied to the determination of PHMB-HCl in some contact-lens detergents.

  14. Kinetically controlled glass transition measurement of organic aerosol thin films using broadband dielectric spectroscopy

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2018-06-01

    Full Text Available Glass transitions from liquid to semi-solid and solid phase states have important implications for reactivity, growth, and cloud-forming (cloud condensation nuclei and ice nucleation capabilities of secondary organic aerosols (SOAs. The small size and relatively low mass concentration of SOAs in the atmosphere make it difficult to measure atmospheric SOA glass transitions using conventional methods. To circumvent these difficulties, we have adapted a new technique for measuring glass-forming properties of atmospherically relevant organic aerosols. Aerosol particles to be studied are deposited in the form of a thin film onto an interdigitated electrode (IDE using electrostatic precipitation. Dielectric spectroscopy provides dipole relaxation rates for organic aerosols as a function of temperature (373 to 233 K that are used to calculate the glass transition temperatures for several cooling or heating rates. IDE-enabled broadband dielectric spectroscopy (BDS was successfully used to measure the kinetically controlled glass transition temperatures of aerosols consisting of glycerol and four other compounds with selected cooling and heating rates. The glass transition results agree well with available literature data for these five compounds. The results indicate that the IDE-BDS method can provide accurate glass transition data for organic aerosols under atmospheric conditions. The BDS data obtained with the IDE-BDS technique can be used to characterize glass transitions for both simulated and ambient organic aerosols and to model their climate effects.

  15. Colloidal titration of aqueous zirconium solutions with poly(vinyl sulfate) by potentiometric endpoint detection using a toluidine blue selective electrode.

    Science.gov (United States)

    Sakurada, Osamu; Kato, Yasutake; Kito, Noriyoshi; Kameyama, Keiichi; Hattori, Toshiaki; Hashiba, Minoru

    2004-02-01

    Zirconium oxy-salts were hydrolyzed to form positively charged polymer or cluster species in acidic solutions. The zirconium hydrolyzed polymer was found to react with a negatively charged polyelectrolyte, such as poly(vinyl sulfate), and to form a stoichiometric polyion complex. Thus, colloidal titration with poly(vinyl sulfate) was applied to measure the zirconium concentration in an acidic solution by using a Toluidine Blue selective plasticized poly(vinyl chloride) membrane electrode as a potentiometric end-point detecting device. The determination could be performed with 1% of the relative standard deviation. The colloidal titration stoichiometry at pH < or = 2 was one mol of zirconium per equivalent mol of poly(vinyl sulfate).

  16. Properties Of Soda/Yttria/Silica Glasses

    Science.gov (United States)

    Angel, Paul W.; Hann, Raiford E.

    1994-01-01

    Experimental study of glass-formation compositional region of soda/ yttria/silicate system and of selected physical properties of glasses within compositional region part of continuing effort to identify glasses with high coefficients of thermal expansion and high softening temperatures, for use as coatings on superalloys and as glass-to-metal seals.

  17. Measuring calcium, potassium, and nitrate in plant nutrient solutions using ion-selective electrodes in hydroponic greenhouse of some vegetables.

    Science.gov (United States)

    Vardar, Gökay; Altıkatoğlu, Melda; Ortaç, Deniz; Cemek, Mustafa; Işıldak, İbrahim

    2015-01-01

    Generally, the life cycle of plants depends on the uptake of essential nutrients in a balanced manner and on toxic elements being under a certain concentration. Lack of control of nutrient levels in nutrient solution can result in reduced plant growth and undesired conditions such as blossom-end rot. In this study, sensitivity and selectivity tests for various polyvinylchloride (PVC)-based ion-selective membranes were conducted to identify those suitable for measuring typical concentration ranges of macronutrients, that is, NO(3-), K(+), and Ca(2+), in hydroponic solutions. The sensitivity and selectivity of PVC-membrane-based ion-selective sensors prepared with tetradodecylammoniumnitrate for NO(3-), valinomycin for K(+), and Ca ionophore IV for Ca(2+) were found to be satisfactory for measuring NO(3-), K(+), and Ca(2+) ions in nutrient solutions over typical ranges of hydroponic concentrations. Potassium, calcium, and nitrate levels that were utilized by cucumber and tomato seedlings in the greenhouse were different. The findings show that tomato plants consumed less amounts of nitrate than cucumber plants over the first 2 months of their growth. We also found that the potassium intake was higher than other nutritional elements tested for all plants. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

  18. Selective electronalysis of peracetic acid in the presence of a large excess of H{sub 2}O{sub 2} at Au(1 1 1)-like gold electrode

    Energy Technology Data Exchange (ETDEWEB)

    Awad, M.I., E-mail: mawad70@yahoo.com [Department of Chemistry, Faculty of Science, Cairo University (Egypt)

    2012-06-12

    Highlights: Black-Right-Pointing-Pointer Analysis of peracetic acid in the presence of a large excess of H{sub 2}O{sub 2} is introduced. Black-Right-Pointing-Pointer Au(1 1 1)-like gold electrode serves as an ideal for this purpose. Black-Right-Pointing-Pointer The analysis is characterized by high selectivity and sensitivity. - Abstract: Peracetic acid (PAA) has been selectively electroanalyzed in the presence of a large excess of hydrogen peroxide (H{sub 2}O{sub 2}), about 500 fold that of PAA, using Au (1 1 1)-like gold electrode in acetate buffer solutions of pH 5.4. Au(1 1 1)-like gold electrode was prepared by a controlled reductive desorption of a previously assembled thiol, typically cysteine, monolayer onto the polycrystalline gold (poly-Au) electrode. Cysteine molecules were selectively removed from the Au(1 1 1) facets of the poly-Au electrode, keeping the other two facets (i.e., Au(1 1 0) and Au(1 0 0)) under the protection of the adsorbed cysteine. It has been found that Au(1 1 1)-like gold electrode positively shifts the reduction peak of PAA, while, fortunately, shifts the reduction peak of H{sub 2}O{sub 2} negatively, achieving a large potential separation (around 750 mV) between the two reduction peaks as compared with that (around 450 mV) obtained at the poly-Au electrode. This large potential separation between the two reduction peaks enabled the analysis of PAA in the presence of a large excess of H{sub 2}O{sub 2}. In addition, the positive shift of the reduction peak of PAA gives the present method a high immunity against the interference of the dissolved oxygen.

  19. Glass consistency and glass performance

    International Nuclear Information System (INIS)

    Plodinec, M.J.; Ramsey, W.G.

    1994-01-01

    Glass produced by the Defense Waste Processing Facility (DWPF) will have to consistently be more durable than a benchmark glass (evaluated using a short-term leach test), with high confidence. The DWPF has developed a Glass Product Control Program to comply with this specification. However, it is not clear what relevance product consistency has on long-term glass performance. In this report, the authors show that DWPF glass, produced in compliance with this specification, can be expected to effectively limit the release of soluble radionuclides to natural environments. However, the release of insoluble radionuclides to the environment will be limited by their solubility, and not glass durability

  20. Boosted selective internal radiation therapy with 90Y-loaded glass microspheres (B-SIRT) for hepatocellular carcinoma patients: a new personalized promising concept

    International Nuclear Information System (INIS)

    Garin, E.; Lenoir, L.; Edeline, J.; Laffont, S.; Mesbah, H.; Poree, P.; Sulpice, L.; Boudjema, K.; Mesbah, M.; Guillygomarc'h, A.; Quehen, E.; Pracht, M.; Raoul, J.L.; Clement, B.; Rolland, Y.; Boucher, E.

    2013-01-01

    To evaluate the impact of dosimetry based on MAA SPECT/CT for the prediction of response, toxicity and survival, and for treatment planning in patients with hepatocellular carcinoma (HCC) treated with 90 Y-loaded glass microspheres (TheraSphere registered). TheraSphere registered was administered to 71 patients with inoperable HCC. MAA SPECT/CT quantitative analysis was used for the calculation of the tumour dose (TD), healthy injected liver dose (HILD), and total injected liver dose. Response was evaluated at 3 months using EASL criteria. Time to progression (TTP) and overall survival (OS) were evaluated using the Kaplan-Meier method. Factors potentially associated with liver toxicity were combined to construct a liver toxicity score (LTS). The response rate was 78.8 %. Median TD were 342 Gy for responding lesions and 191 Gy for nonresponding lesions (p 205 Gy (p = 0.0015 and not significant). Among patients with portal vein thrombosis (PVT) (n = 33), the median TTP and OS were 4.5 months (2-7 months) and 5 months (2-8 months), respectively, in patients with TD 205 Gy (p = 0.039 and 0.005). The median OS was 24.5 months (18-28.5 months) in PVT patients with TD >205 Gy and good PVT targeting on MAA SPECT/CT. The LTS was able to detect severe liver toxicity (n = 6) with a sensitivity of 83 % and overall accuracy of 97 %. Dosimetry based on MAA SPECT/CT was able to accurately predict response and survival in patients treated with glass microspheres. This method can be used to adapt the injected activity without increasing liver toxicity, thus defining a new concept of boosted selective internal radiation therapy (B-SIRT). This new concept and LTS enable fully personalized treatment planning with glass microspheres to be achieved. (orig.)

  1. Boosted selective internal radiation therapy with 90Y-loaded glass microspheres (B-SIRT) for hepatocellular carcinoma patients: a new personalized promising concept.

    Science.gov (United States)

    Garin, E; Lenoir, L; Edeline, J; Laffont, S; Mesbah, H; Porée, P; Sulpice, L; Boudjema, K; Mesbah, M; Guillygomarc'h, A; Quehen, E; Pracht, M; Raoul, J L; Clement, B; Rolland, Y; Boucher, E

    2013-07-01

    To evaluate the impact of dosimetry based on MAA SPECT/CT for the prediction of response, toxicity and survival, and for treatment planning in patients with hepatocellular carcinoma (HCC) treated with (90)Y-loaded glass microspheres (TheraSphere®). TheraSphere® was administered to 71 patients with inoperable HCC. MAA SPECT/CT quantitative analysis was used for the calculation of the tumour dose (TD), healthy injected liver dose (HILD), and total injected liver dose. Response was evaluated at 3 months using EASL criteria. Time to progression (TTP) and overall survival (OS) were evaluated using the Kaplan-Meier method. Factors potentially associated with liver toxicity were combined to construct a liver toxicity score (LTS). The response rate was 78.8%. Median TD were 342 Gy for responding lesions and 191 Gy for nonresponding lesions (p 205 Gy (p = 0.0015 and not significant). Among patients with portal vein thrombosis (PVT) (n = 33), the median TTP and OS were 4.5 months (2-7 months) and 5 months (2-8 months), respectively, in patients with TD 205 Gy (p = 0.039 and 0.005). The median OS was 24.5 months (18-28.5 months) in PVT patients with TD >205 Gy and good PVT targeting on MAA SPECT/CT. The LTS was able to detect severe liver toxicity (n = 6) with a sensitivity of 83% and overall accuracy of 97%. Dosimetry based on MAA SPECT/CT was able to accurately predict response and survival in patients treated with glass microspheres. This method can be used to adapt the injected activity without increasing liver toxicity, thus defining a new concept of boosted selective internal radiation therapy (B-SIRT). This new concept and LTS enable fully personalized treatment planning with glass microspheres to be achieved.

  2. Radioresistance of inorganic glasses

    International Nuclear Information System (INIS)

    Vorob'ev, A.A.; Zavadovskaya, E.K.; Fedorov, B.V.; Starodubtsev, V.A.

    1977-01-01

    Regularities are considered in the variation of properties of glass due to irradiations. On the basis of previous theoretical statements and experimental investigations, it is inferred that the irradiation resistance of glasses of the same type, synthesis conditions, content of impurities and amount of imperfections, is a function of the ''element-oxygen'' bond energy. The irradiation resistance depends on the number and the nature of glass structure imperfections. The averaged level of bonding forces is indicative of the glass formation temperature; the imperfections in glasses are formed in structure elements whose amount predominates as compared to the others. Electric charges which accumulate on the crack surface tend to increase its size, thus lessening even further the electric strength of the dielectric. The greater the irradiation time, the greater the number of irradiation imperfections causing a drop in the electric strength of glass. When choosing a glass for service in a radiation field, it is necessary to select those of a highest temperature of glass formation and with a least amount of imperfections

  3. Colloidal glasses

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Colloidal glasses. Glassy state is attained when system fails to reach equilibrium due to crowding of constituent particles. In molecular glasses, glassy state is reached by rapidly lowering the temperature. In colloidal glasses, glassy state is reached by increasing the ...

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

    Czech Academy of Sciences Publication Activity Database

    Langmaier, Jan; Trojánek, Antonín; Samec, Zdeněk

    2009-01-01

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

  5. Nafion covered core–shell structured Fe{sub 3}O{sub 4}@graphene nanospheres modified electrode for highly selective detection of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wuxiang; Zheng, Jianzhong; Shi, Jiangu; Lin, Zhongqiu; Huang, Qitong; Zhang, Hanqiang; Wei, Chan [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Chen, Jianhua [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province University Key Laboratory of Analytical Science, Minnan Normal University, Zhangzhou 363000 (China); Hu, Shirong, E-mail: Hushirong6666@163.com [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province University Key Laboratory of Analytical Science, Minnan Normal University, Zhangzhou 363000 (China); School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Hao, Aiyou [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2015-01-01

    Graphical abstract: Schematic illustration of the reaction mechanism of Fe{sub 3}O{sub 4}@GNs/Nafion with DA. - Highlights: • The sensor based on Fe{sub 3}O{sub 4}@graphene nanospheres was prepared for the first time. • The biosensor shows a wide linear range and a lower detection limit of 0.007 μM. • This method was successfully applied to detection of DA in real samples. - Abstract: Nafion covered core–shell structured Fe{sub 3}O{sub 4}@graphene nanospheres (GNs) modified glassy carbon electrode (GCE) was successfully prepared and used for selective detection dopamine. Firstly, the characterizations of hydro-thermal synthesized Fe{sub 3}O{sub 4}@GNs were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Then Fe{sub 3}O{sub 4}@GNs/Nafion modified electrode exhibited excellent electrocatalytic activity toward the oxidations of dopamine (DA). The interference test showed that the coexisted ascorbic acid (AA) and uric acid (UA) had no electrochemical interference toward DA. Under the optimum conditions, the broad linear relationship was obtained in the experimental concentration from 0.020 μM to 130.0 μM with the detection limit (S/N = 3) of 0.007 μM. Furthermore, the core–shell structured Fe{sub 3}O{sub 4}@GNs/Nafion/GCE was applied to the determination of DA in real samples and satisfactory results were got, which could provide a promising platform to develop excellent biosensor for detecting DA.

  6. Comparative study of 2-hydroxy propyl beta cyclodextrin and calixarene as ionophores in potentiometric ion-selective electrodes for neostigmine bromide.

    Science.gov (United States)

    El-Kosasy, Amira M; Nebsen, Marianne; Abd El-Rahman, Mohamed K; Salem, Maissa Y; El-Bardicy, Mohamed G

    2011-08-15

    Three novel neostigmine bromide (NEO) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticiser in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using tetrakis(4-chlorophenyl)borate (TpClPB) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor 3 was constructed using 4-sulfocalix-8-arene as an ionophore. Linear responses of NEO within the concentration ranges of 10(-5) to 10(-2), 10(-6) to 10(-2) and 10(-7) to 10(-2) mol L(-1) were obtained using sensors 1, 2 and 3, respectively. Nernstian slopes of 51.6 ± 0.8, 52.9 ± 0.6 and 58.6 ± 0.4 mV/decade over the pH range of 4-9 were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for NEO. The utility of 2-hydroxy propyl β-cyclodextrin and 4-sulfocalix[8]arene as ionophores had a significant influence on increasing the membrane sensitivity and selectivity of sensors 2 and 3 compared to sensor 1. The proposed sensors displayed useful analytical characteristics for the determination of NEO in bulk powder, different pharmaceutical formulations, and biological fluids (plasma and cerebrospinal fluid (CSF)) and in the presence of its degradation product (3-hydroxyphenyltrimethyl ammonium bromide) and thus could be used for stability-indicating methods. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Determination of water quality of ground water in selected Payatas residential areas using ion-selective electrodes (ISE) and atomic absorption spectroscopy (AAS) (determination of NO3, Cl, Pb, Cd, Zn)

    International Nuclear Information System (INIS)

    Tahir, Samsudin A.; Roque, Willie P.; Arididon, Bonifacio D. Jr.; Gardon, Ruel W.

    2003-01-01

    This study aims to determine the water-soluble ions using ion-selective electrodes (ISE) and trace metals using atomic absorption spectroscopy (AAS). Seven water samples were chosen from the thirteen sites, which were gathered from the selected Payatas residential areas in Quezon City. For the trace metals the lowest detection of AAS in lead was obtained in La Brea site and was found to be -0.5 ppm. Lead content has a value of -0.04 ppm and was found to be below the detection limit of 0.1 ppm. The remaining sites obtained high value of lead concentrations in AAS reading. The range of concentration for lead was from 0.5 ppm for La Brea site to 1.4 ppm for Velasco site. The cadmium as trace metal in groundwater samples from Payatas residential area was found to be below the lowest limit of detection ( 3 which is 15.6 ppm and it was obtained by the used of ion selective electrodes (ISE) Horiba model type. Second to it was the La Brea site, which is 10.04 ppm All the other samples do not exceeds to the maximum allowable concentration of nitrate (50.0 ppm), and it ranged from 4.10 ppm for open-well site to 15.6 ppm for Lopez site. In chloride determination, Lagro High School obtained a reading of 57.6 ppm using ISE and it was the highest concentration amount present in seven samples. Next to it was the Ungrin site (36.8 ppm), samples ranged from 6.7 ppm for La Brea site to 57.6 ppm for Lagro high school site. All the samples do not exceeds to the maximum allowable concentration for chloride, which is 250 ppm. (Authors)

  8. Liquid electrode

    Science.gov (United States)

    Ekechukwu, A.A.

    1994-07-05

    A dropping electrolyte electrode is described for use in electrochemical analysis of non-polar sample solutions, such as benzene or cyclohexane. The liquid electrode, preferably an aqueous salt solution immiscible in the sample solution, is introduced into the solution in dropwise fashion from a capillary. The electrolyte is introduced at a known rate, thus, the droplets each have the same volume and surface area. The electrode is used in making standard electrochemical measurements in order to determine properties of non-polar sample solutions. 2 figures.

  9. Microfluidic sensor for ultra high redox cycling amplification for highly selective electrochemical measurements

    NARCIS (Netherlands)

    Odijk, Mathieu; Straver, Martin; Olthuis, Wouter; van den Berg, Albert

    2011-01-01

    In this contribution a SU8/glass-based microfluidic sensor is described with two closely spaced parallel electrodes for highly selective measurements using the redox cycling (RC) effect. Using this sensor, a RC amplification of ~2000x is measured using the ferrocyanide redox couple, which is much

  10. Silicate glasses

    International Nuclear Information System (INIS)

    Lutze, W.

    1988-01-01

    Vitrification of liquid high-level radioactive wastes has received the greatest attention, world-wide, compared to any other HLW solidification process. The waste form is a borosilicate-based glass. The production of phosphate-based glass has been abandoned in the western world. Only in the Soviet Union are phosphate-based glasses still being developed. Vitrification techniques, equipment and processes and their remote operation have been developed and studied for almost thirty years and have reached a high degree of technical maturity. Industrial demonstration of the vitrification process has been in progress since 1978. This chapter is a survey of world-wide research and development efforts in nuclear waste glasses and its production technology. The principal glasses considered are silicate glasses which contain boron, i.e., borosilicate glasses

  11. Electrochemical photovoltaic cells and electrodes

    Science.gov (United States)

    Skotheim, Terje A.

    1984-01-01

    Improved electrochemical photovoltaic cells and electrodes for use therein, particularly electrodes employing amorphous silicon or polyacetylene coating are produced by a process which includes filling pinholes or porous openings in the coatings by electrochemical oxidation of selected monomers to deposit insulating polymer in the openings.

  12. Improved photovoltaic cells and electrodes

    Science.gov (United States)

    Skotheim, T.A.

    1983-06-29

    Improved photovoltaic cells and electrodes for use therein, particularly electrodes employing amorphous silicon or polyacetylene coating are produced by a process which includes filling pinholes or porous openings in the coatings by electrochemical oxidation of selected monomers to deposit insulating polymer in the openings.

  13. Crystallization of Yttrium and Samarium Aluminosilicate Glasses

    OpenAIRE

    Lago, Diana Carolina; Prado, Miguel Oscar

    2016-01-01

    Aluminosilicate glasses containing samarium and yttrium (SmAS and YAS glasses) exhibit high glass transition temperatures, corrosion resistance, and glass stability on heating which make them useful for technological applications. Yttrium aluminosilicate glass microspheres are currently being used for internal selective radiotherapy of liver cancer. During the preparation process, crystallization needs to be totally or partially avoided depending on the final application. Thus knowing the cry...

  14. Glass Membrane For Controlled Diffusion Of Gases

    Science.gov (United States)

    Shelby, James E.; Kenyon, Brian E.

    2001-05-15

    A glass structure for controlled permeability of gases includes a glass vessel. The glass vessel has walls and a hollow center for receiving a gas. The glass vessel contains a metal oxide dopant formed with at least one metal selected from the group consisting of transition metals and rare earth metals for controlling diffusion of the gas through the walls of the glass vessel. The vessel releases the gas through its walls upon exposure to a radiation source.

  15. electrode array

    African Journals Online (AJOL)

    PROF EKWUEME

    A geoelectric investigation employing vertical electrical soundings (VES) using the Ajayi - Makinde Two-Electrode array and the ... arrangements used in electrical D.C. resistivity survey. These include ..... Refraction Tomography to Study the.

  16. Field testing of sulphide electrodes

    International Nuclear Information System (INIS)

    Singh, P.R.; Gaonkar, K.B.; Gadiyar, H.S.

    1993-01-01

    Sulphide ion selective electrodes have been developed at BARC, for determination of Ag + and S - ions directly and Cl - and CN - ions indirectly. The electrodes were tested for their use in sulphide environments in the EAD (Effluent After Dilution) stream at the Heavy Water Plant, Kota. The electrodes are suitable in the concentration range of 16000 ppm to 0.002 ppm, with a slope of 29-31 mV per decade change in the sulphide ion concentration. The response time is less than 10 seconds. These electrodes are reliable for continuous on-line use for a long period. (author). 7 refs., 11 figs., 1 tab

  17. Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results

    International Nuclear Information System (INIS)

    Coles, D.G.

    1981-01-01

    A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for 237 Np and 239 Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected the leach rate, but only slightly. Temperature effects were significant. Plutonium leach rate was lower at higher temperature suggesting that Pu sorption onto the beads was enhanced at the higher temperature. The range of leach rates for all analyzed elements (except Pu), at both temperature, at all three flow rates, and with all three leachant compositions varied only three orders of magnitude. The range of variables used in this experiment covered those expected in many proposed repository environments. The preliminary interpretation of the results also indicated that matrix dissolution may be the dominant leaching mechanism, at least for Np in bicarbonate leachant. Regardless of the leaching mechanism the importance of this study is that it bounds the effects of repository environments when the ground water is oxidizing and when it doesn't reach the waste form until the waste has cooled to ambient rock temperature

  18. Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results

    International Nuclear Information System (INIS)

    Coles, D.G.

    1981-01-01

    A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for 237 Np and 239 Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected the leach rate, but only slightly. Temperature effects were significant. Plutonium leach rate was lower at higher temperature suggesting that Pu sorption onto the beads was enhanced at the higher temperature. The range of leach rates for all analyzed elements (except Pu), at both temperatures, at all three flow rates, and with all three leachant compositions varied over only three orders of magnitude. The range of variables used in this experiment covered those expected in many proposed repository environments. The preliminary interpretation of the results aPPh 3 also reacted with Mn 2 (CO) 10 and Cp 2 Mo 2 (CO) 6 to give a variety of products at room temperature. A radical mechanism was suggested

  19. The Novel SCN''- Ion-selective Electrode Based on the 1-Benzyl-3-(4-nitrophenyl) thio-urea Ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Mi; Kang, Dong Hyeon; Choe, Ju Eun; You, Jung Min; Go, Min Jeong; Lee, Jung Seong; Jeon, Seung Won [Chungnam National University, Daejeon (Korea, Republic of)

    2014-09-15

    A potentiometric sensor based on the 1-benzyl-3-(4-nitrophenyl) thio-urea was synthesized and tested as an ionophore in PVC based membrane sensor towards SCN - ions. This membrane exhibits a linear stable response over a wide concentration range (1.0 × 10''-5 to 1.0 × 10''-2 M) with a slope of -59.2 mV/dec., a detection limit of log[SCN''- ] = -5.05, and a selectivity coefficient for thiocyanate against perchlorate anion of logK{sub s}cn''pot = -0.133. The selectivity series of the membrane is as follows: SCN''- > ClO{sub 4}''- > I''- >NO{sub 3}''- >HSO{sub 3}''- > Cl''-HSO{sub '}'-''4 > F''- > CH{sub 3}COO''- > HCO''-''3 > Br''- > H{sub 2}PO{sub 4}''- > SO{sub 3}''-''2 > SO{sub 4}''-''2 > CO{sub 3}''-''2. The proposed electrode showed good selectivity and a good response for the SCN''- ion over a wide variety of other anions in pH 6.0 buffer solutions and has a fast response time of about < 5s.. The influences of the membrane by pH, ionophore, and plasticizer were studied.

  20. Transparent Electrodes for Efficient Optoelectronics

    KAUST Repository

    Morales-Masis, Monica

    2017-03-30

    With the development of new generations of optoelectronic devices that combine high performance and novel functionalities (e.g., flexibility/bendability, adaptability, semi or full transparency), several classes of transparent electrodes have been developed in recent years. These range from optimized transparent conductive oxides (TCOs), which are historically the most commonly used transparent electrodes, to new electrodes made from nano- and 2D materials (e.g., metal nanowire networks and graphene), and to hybrid electrodes that integrate TCOs or dielectrics with nanowires, metal grids, or ultrathin metal films. Here, the most relevant transparent electrodes developed to date are introduced, their fundamental properties are described, and their materials are classified according to specific application requirements in high efficiency solar cells and flexible organic light-emitting diodes (OLEDs). This information serves as a guideline for selecting and developing appropriate transparent electrodes according to intended application requirements and functionality.

  1. Transparent Electrodes for Efficient Optoelectronics

    KAUST Repository

    Morales-Masis, Monica; De Wolf, Stefaan; Woods-Robinson, Rachel; Ager, Joel W.; Ballif, Christophe

    2017-01-01

    With the development of new generations of optoelectronic devices that combine high performance and novel functionalities (e.g., flexibility/bendability, adaptability, semi or full transparency), several classes of transparent electrodes have been developed in recent years. These range from optimized transparent conductive oxides (TCOs), which are historically the most commonly used transparent electrodes, to new electrodes made from nano- and 2D materials (e.g., metal nanowire networks and graphene), and to hybrid electrodes that integrate TCOs or dielectrics with nanowires, metal grids, or ultrathin metal films. Here, the most relevant transparent electrodes developed to date are introduced, their fundamental properties are described, and their materials are classified according to specific application requirements in high efficiency solar cells and flexible organic light-emitting diodes (OLEDs). This information serves as a guideline for selecting and developing appropriate transparent electrodes according to intended application requirements and functionality.

  2. Flexible transparent electrode

    Science.gov (United States)

    Demiryont, Hulya; Shannon, Kenneth C., III; Moorehead, David; Bratcher, Matthew

    2011-06-01

    This paper presents the properties of the EclipseTECTM transparent conductor. EclipseTECTM is a room temperature deposited nanostructured thin film coating system comprised of metal-oxide semiconductor elements. The system possesses metal-like conductivity and glass-like transparency in the visible region. These highly conductive TEC films exhibit high shielding efficiency (35dB at 1 to 100GHz). EclipseTECTM can be deposited on rigid or flexible substrates. For example, EclipseTECTM deposited on polyethylene terephthalate (PET) is extremely flexible that can be rolled around a 9mm diameter cylinder with little or no reduction in electrical conductivity and that can assume pre-extension states after an applied stress is relieved. The TEC is colorless and has been tailored to have high visible transmittance which matches the eye sensitivity curve and allows the viewing of true background colors through the coating. EclipseTECTM is flexible, durable and can be tailored at the interface for applications such as electron- or hole-injecting OLED electrodes as well as electrodes in flexible displays. Tunable work function and optical design flexibility also make EclipseTECTM well-suited as a candidate for grid electrode replacement in next-generation photovoltaic cells.

  3. Linear particle accelerator with seal structure between electrodes and insulators

    Science.gov (United States)

    Broadhurst, John H.

    1989-01-01

    An electrostatic linear accelerator includes an electrode stack comprised of primary electrodes formed or Kovar and supported by annular glass insulators having the same thermal expansion rate as the electrodes. Each glass insulator is provided with a pair of fused-in Kovar ring inserts which are bonded to the electrodes. Each electrode is designed to define a concavo-convex particle trap so that secondary charged particles generated within the accelerated beam area cannot reach the inner surface of an insulator. Each insulator has a generated inner surface profile which is so configured that the electrical field at this surface contains no significant tangential component. A spark gap trigger assembly is provided, which energizes spark gaps protecting the electrodes affected by over voltage to prevent excessive energy dissipation in the electrode stack.

  4. Recycle Glass in Foam Glass Production

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    The foam glass industry turn recycle glass into heat insulating building materials. The foaming process is relative insensitive to impurities in the recycle glass. It is therefore considered to play an important role in future glass recycling. We show and discuss trends of use of recycled glasses...... in foam glass industry and the supply sources and capacity of recycle glass....

  5. Characteristics of NH4+ and NO3− fluxes in tea (Camellia sinensis) roots measured by scanning ion-selective electrode technique

    Science.gov (United States)

    Ruan, Li; Wei, Kang; Wang, Liyuan; Cheng, Hao; Zhang, Fen; Wu, Liyun; Bai, Peixian; Zhang, Chengcai

    2016-01-01

    As a vital beverage crop, tea has been extensively planted in tropical and subtropical regions. Nitrogen (N) levels and forms are closely related to tea quality. Based on different N levels and forms, we studied changes in NO3− and NH4+ fluxes in tea roots utilizing scanning ion-selective electrode technique. Our results showed that under both single and mixed N forms, influx rates of NO3− were much lower than those of NH4+, suggesting a preference for NH4+ in tea. With the increase in N concentration, the influx rate of NO3− increased more than that of NH4+. The NH4+ influx rates in a solution without NO3− were much higher than those in a solution with NO3−, while the NO3− influx rates in a solution without NH4+ were much lower than those in a solution with NH4+. We concluded that (1) tea roots showed a preference for NH4+, (2) presence of NO3− had a negative effect on NH4+ influx, and (3) NH4+ had a positive effect on NO3− influx. Our findings not only may help advance hydroponic tea experiments but also may be used to develop efficient fertilization protocols for soil-grown tea in the future. PMID:27918495

  6. Highly sensitive and selective voltammetric detection of mercury(II) using an ITO electrode modified with 5-methyl-2-thiouracil, graphene oxide and gold nanoparticles

    International Nuclear Information System (INIS)

    Zhou, N.; Chen, H.; Li, J.; Chen, L.

    2013-01-01

    We have developed an electrochemical sensor for highly selective and sensitive determination of Hg(II). It is based on the specific binding of 5-methyl-2-thiouracil (MTU) and Hg(II) to the surface of an indium tin oxide (ITO) electrode modified with a composite made from graphene oxide (GO) and gold nanoparticles (AuNPs). This leads to a largely enhanced differential pulse voltammetric response for Hg(II). Following optimization of the method, a good linear relationship (R = 0.9920) is found between peak current and the concentration of Hg(II) in the 5.0-110.0 nM range. The limit of detection (LOD) is 0.78 nM at a signal-to-noise ratio of 3. A study on the interference by several metal ions revealed no interferences. The feasibility of this method was demonstrated by the analyses of real water samples. The LODs are 6.9, 1.0 and 1.9 nM for tap water, bottled water and lake water samples, respectively, and recoveries for the water samples spiked with 8.0, 50.0 and 100.0 nM were 83.9-96.8 %, with relative standard deviations ranging from 3.3 % to 5.2 %. (author)

  7. Characteristics of NH4+ and NO3- fluxes in tea (Camellia sinensis) roots measured by scanning ion-selective electrode technique.

    Science.gov (United States)

    Ruan, Li; Wei, Kang; Wang, Liyuan; Cheng, Hao; Zhang, Fen; Wu, Liyun; Bai, Peixian; Zhang, Chengcai

    2016-12-05

    As a vital beverage crop, tea has been extensively planted in tropical and subtropical regions. Nitrogen (N) levels and forms are closely related to tea quality. Based on different N levels and forms, we studied changes in NO 3 - and NH 4 + fluxes in tea roots utilizing scanning ion-selective electrode technique. Our results showed that under both single and mixed N forms, influx rates of NO 3 - were much lower than those of NH 4 + , suggesting a preference for NH 4 + in tea. With the increase in N concentration, the influx rate of NO 3 - increased more than that of NH 4 + . The NH 4 + influx rates in a solution without NO 3 - were much higher than those in a solution with NO 3 - , while the NO 3 - influx rates in a solution without NH 4 + were much lower than those in a solution with NH 4 + . We concluded that (1) tea roots showed a preference for NH 4 + , (2) presence of NO 3 - had a negative effect on NH 4 + influx, and (3) NH 4 + had a positive effect on NO 3 - influx. Our findings not only may help advance hydroponic tea experiments but also may be used to develop efficient fertilization protocols for soil-grown tea in the future.

  8. In-line monitoring of an oxide ion in LiCl molten salt using a YSZ based oxide ion selective electrode

    International Nuclear Information System (INIS)

    Cho, Young Hwan; Jeon, Jong Seon; Yeon, Jei Won; Choi, In Kyu; Kim, Won Ho

    2004-01-01

    The electrode potential characteristics of a YSZ based membrane metal oxide electrode have been studied in molten LiCl at 700 .deg. C by the potentiometric method. The electrode exhibited a good potential response to log[O 2 ] and data reproducibility. The calibration plot (potential vs. log[O 2 ] was found to be linear, obeying the nernst equation. The electrode potential showed a good reversibility corresponding to increase/decrease of the oxide ion present in the molten LiCl. The physical and chemical durability appeared to be sound after several repeated uses, resulting in reproducible results. However, 'the proposed electrode' failed when metallic Li was present in the melt

  9. Super ionic conductive glass

    Science.gov (United States)

    Susman, S.; Volin, K.J.

    Described is an ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A/sub 1 + x/D/sub 2-x/3/Si/sub x/P/sub 3 - x/O/sub 12 - 2x/3/, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  10. Facile one-step direct electrodeposition of bismuth nanowires on glassy carbon electrode for selective determination of folic acid

    International Nuclear Information System (INIS)

    Ananthi, Arjunan; Kumar, Shanmugam Senthil; Phani, Kanala Lakshminarasimha

    2015-01-01

    Highlights: • BiNWs prepared through simple, fast one step electrochemical route. • BiNWs showed more catalytic activity and sensitivity than GC towards FA reduction. • Selective detection of FA was achieved with low limit of detection (9.53 × 10 −9 mol L −1 ). • Real sample analysis was successfully demonstrated using FA pharmaceutical tablets. • BiNWs based sensor matrix is inexpensive, and more suitable for FA real application. - Abstract: In the present work, we have developed a facile one step route to electrodeposition of stabilizer-free bismuth nanowires (BiNWs) on glassy carbon (GC) substrates by using a simple potentiostatic method. Formation of BiNWs on GC substrate was confirmed by field emission scanning electron microscopy (FE-SEM). The growth of BiNWs on the GC substrate was monitored by cyclic voltammetry and found that continuous in-situ generation of hydrogen bubbles during electrodeposition provides a stagnant template for the formation of BiNWs on the GC substrate. Phase-purity of the deposited BiNWs on GC substrate studied by XRD indicates no other oxide formation. The electrodeposited BiNWs on GC substrate was used for electro-reduction of folic acid (FA) and its quantitative determination in Britton-Robinson buffer of pH 4.5 solutions. The observed cyclic voltammetric reduction current of FA on BiNWs/GC is almost 15 times higher with 0.015 V less negative overpotential compared to bare GC substrate alone. This result clearly reveals the electrocatalytic activity of the deposited BiNWs. In addition, square wave voltammetry (SWV) showed a perfectly linear response in the concentration range of 1 × 10 −8 –15 × 10 −8 mol L −1 with a correlation coefficient of 0.9956. The limit of detection (LOD) and limit of quantitation (LOQ) are determined to be 9.53 × 10 −9 and 31.68 × 10 −9 mol L −1 respectively. The response of the BiNWs/GC sensor matrix is not affected by any usual interference from excess concentrations of

  11. Boosted selective internal radiation therapy with {sup 90}Y-loaded glass microspheres (B-SIRT) for hepatocellular carcinoma patients: a new personalized promising concept

    Energy Technology Data Exchange (ETDEWEB)

    Garin, E.; Lenoir, L. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Nuclear Medicine, CS 44229, Rennes (France); University of Rennes 1, Rennes (France); INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Edeline, J. [University of Rennes 1, Rennes (France); Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France); Laffont, S. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Nuclear Medicine, CS 44229, Rennes (France); Mesbah, H.; Poree, P. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Informatics, CS 44229, Rennes (France); Sulpice, L. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Centre Hospitalier Universitaire Pontchaillou, Department of Digestive Surgery, Rennes (France); Boudjema, K. [University of Rennes 1, Rennes (France); INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Centre Hospitalier Universitaire Pontchaillou, Department of Digestive Surgery, Rennes (France); Mesbah, M. [University of Pierre et Marie Curie, Paris (France); Guillygomarc' h, A. [Centre Hospitalier Universitaire Pontchaillou, Department of Hepatology, Rennes (France); Quehen, E. [Centre Hospitalier Universitaire Pontchaillou, Department of Radiology, Rennes (France); Pracht, M. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France); Raoul, J.L. [Comprehensive Cancer Center, Institute Paoli Calmette, Department of Medical Oncology, Marseille (France); Clement, B. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Rolland, Y. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Imaging, CS 44229, Rennes (France); Boucher, E. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France)

    2013-07-15

    able to accurately predict response and survival in patients treated with glass microspheres. This method can be used to adapt the injected activity without increasing liver toxicity, thus defining a new concept of boosted selective internal radiation therapy (B-SIRT). This new concept and LTS enable fully personalized treatment planning with glass microspheres to be achieved. (orig.)

  12. Poly(3,4-ethylenedioxythiophene-co-(5-amino-2-naphthalenesulfonic acid)) (PEDOT-PANS) film modified glassy carbon electrode for selective detection of dopamine in the presence of ascorbic acid and uric acid

    International Nuclear Information System (INIS)

    Balamurugan, A.; Chen Shenming

    2007-01-01

    Poly(3,4-ethylenedioxythiophene-co-(5-amino-2-naphthalenesulfonic acid)) (PEDOT-PANS) film modified glassy carbon electrode was prepared by electrochemical polymerization technique. The properties of modified electrode was studied. It was found that the electrochemical properties of modified electrode was very much dependent on the experimental conditions, such as monomer oxidation potential and pH. The modified electrode surface was characterized by scanning electron microscopy (SEM). The PEDOT-PANS film modified electrode shows electrocatalytic activity toward oxidation of dopamine (DA) in acetate buffer solution (pH 5.0) and results in a marked enhancement of the current response. The linear sweep voltammetric (LSV) peak heights are linear with DA concentration from 2 x 10 -6 to 1 x 10 -5 M. The detection limit is 5 x 10 -7 M. More over, the interferences of ascorbic acid (AA) and uric acid (UA) were effectively diminished. This work provides a simple and easy approach for selective determination of dopamine in the presence of ascorbic acid and uric acid

  13. Highly Sensitive and Selective Detection of Dopamine at Poly(chromotrope 2B)-Modified Glassy Carbon Electrode in the Presence of Uric Acid and Ascorbic Acid

    International Nuclear Information System (INIS)

    Li, Xiao-Bo; Rahman, Md. Mahbubur; Xu, Guang-Ri; Lee, Jae-Joon

    2015-01-01

    A highly sensitive and selective electrochemical method based on a poly(chromotrope 2B)-modified anodized glassy carbon electrode (PCHAGCE) was developed for the determination of dopamine (DA) in the presence of uric acid (UA) and ascorbic acid (AA). The PCHAGCE sensor exhibited excellent electron-mediating behavior towards the oxidation of DA in 0.1 M phosphate buffer solution (PBS) (pH 7.0). It was found that the electrocatalytic activity was significantly dependent on the charge status and molecular structure of the target molecules. Differential pulse voltammetry (DPV) measurements revealed oxidation signals for DA, UA, and AA that were well-resolved into three distinct peaks with AA–DA, DA–UA, and AA–UA peak potential separations (ΔE p ) of 172, 132, and 304 mV, respectively. A detection limit of 0.04 ± 0.001 μM (S/N = 3) and a quantification limit (S/N = 10) of 0.149 ± 0.03 μM were obtained for DA sensing in a linear range of 1 to 40 μM in PBS (pH 7.0) with a very high sensitivity of 1.522 ± 0.032 μA·μM −1 . The DA concentrations in human urine samples were also successfully determined with recoveries of 94.0–98.0%. This approach provides a simple, easy, sensitive, and selective method to detect DA in the presence of AA and UA

  14. Cermet electrode

    Science.gov (United States)

    Maskalick, Nicholas J.

    1988-08-30

    Disclosed is a cermet electrode consisting of metal particles of nickel, cobalt, iron, or alloys or mixtures thereof immobilized by zirconia stabilized in cubic form which contains discrete deposits of about 0.1 to about 5% by weight of praseodymium, dysprosium, terbium, or a mixture thereof. The solid oxide electrode can be made by covering a substrate with particles of nickel, cobalt, iron, or mixtures thereof, growing a stabilized zirconia solid oxide skeleton around the particles thereby immobilizing them, contacting the skeleton with a compound of praseodymium, dysprosium, terbium, or a mixture thereof, and heating the skeleton to a temperature of at least 500.degree. C. The electrode can also be made by preparing a slurry of nickel, cobalt, iron, or mixture and a compound of praseodymium, dysprosium, terbium, or a mixture thereof, depositing the slurry on a substrate, heating the slurry to dryness, and growing a stabilized zirconia skeleton around the metal particles.

  15. Microbial electrode sensor for alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Hikuma, M [Ajinomoto Co., Inc., Kawasaki, Japan; Kubo, T; Yasuda, T; Karube, I; Suzuki, S

    1979-10-01

    A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within +- 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

  16. Cosmos & Glass

    DEFF Research Database (Denmark)

    Beim, Anne

    1996-01-01

    The article unfolds the architectural visions of glass by Bruno Taut. It refers to inspirations by Paul Sheerbart and litterature and the Crystal Chain, also it analyses the tectonic univers that can be found in the glass pavillion for the Werkbund exposition in Cologne....

  17. Glass Glimpsed

    DEFF Research Database (Denmark)

    Lock, Charles

    2015-01-01

    Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology.......Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology....

  18. Spin glasses

    CERN Document Server

    Bovier, Anton

    2007-01-01

    Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

  19. Magnetohydrodynamic electrode

    International Nuclear Information System (INIS)

    1980-01-01

    The object of the invention is the provision of a material capable of withstanding a high-temperature, corrosive and erosive environment for use as a ceramic-metal composite electrode current collector in the channel of a magnetohydrodynamic generator. (U.K.)

  20. Monitoring drilling mud composition using flowing liquid junction electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Jasinski, R; Fletcher, P; Vercaemer, C

    1990-06-27

    The concentration of a chosen ionic component of a drilling mud is determined from the potential difference between an ion selective electrode, selective to the component and a reference electrode, the reference electrode being connected to the mud by a liquid junction through which reference electrolyte flows from the electrode to the mud. The system avoids errors due to undesirable interactions between the mud and the reference electrode materials. (author).

  1. An ultrasensitive and selective electrochemical sensor for determination of estrone 3-sulfate sodium salt based on molecularly imprinted polymer modified carbon paste electrode.

    Science.gov (United States)

    Song, Han; Wang, Yuli; Zhang, Lu; Tian, Liping; Luo, Jun; Zhao, Na; Han, Yajie; Zhao, Feilang; Ying, Xue; Li, Yingchun

    2017-11-01

    A highly sensitive and selective electrochemical sensor based on carbon paste electrode (CPE) modified with molecularly imprinted polymers (MIPs) has been developed for the determination of estrone 3-sulfate sodium salt (ESS). MIPs were prepared in polar medium via bulk polymerization and characterized by scanning electron microscopy and infrared spectroscopy. Cyclic voltammetry was performed to the study preparation process and binding behavior of the MIP-modified CPE (MIP/CPE) toward ESS. The conditions for preparing MIPs and MIP/CPE as well as ESS detection were optimized. Under the optimal experimental conditions, the detection linear range for ESS is 4 × 10 -12 to 6 × 10 -9  M with a limit of detection of 1.18 × 10 -12  M (S/N = 3). In addition, the sensor exhibits high binding affinity toward ESS over its structural analogues with excellent repeatability and stability. The fabricated MIP/CPE was then successfully employed to detect ESS in pregnant mare urine (PMU) without any pretreatment, and the average recoveries were from 99.6 to 104.9% with relative standard deviation less than 3.0%. High-performance liquid chromatography was adopted as a reference to validate the established approach in detecting ESS and their results showed good agreement. The as-prepared sensor has high potential to be a decent tool for on-site determination of ESS in PMU in a fast and convenient manner. Graphical Abstract ᅟ.

  2. Selective and rapid monitoring of dual platelet inhibition by aspirin and P2Y12 antagonists by using multiple electrode aggregometry

    Directory of Open Access Journals (Sweden)

    Lorenz Reinhard

    2010-05-01

    Full Text Available Abstract Background Poor platelet inhibition by aspirin or clopidogrel has been associated with adverse outcomes in patients with cardiovascular diseases. A reliable and facile assay to measure platelet inhibition after treatment with aspirin and a P2Y12 antagonist is lacking. Multiple electrode aggregometry (MEA, which is being increasingly used in clinical studies, is sensitive to platelet inhibition by aspirin and clopidogrel, but a critical evaluation of MEA monitoring of dual anti-platelet therapy with aspirin and P2Y12 antagonists is missing. Design and Methods By performing in vitro and ex vivo experiments, we evaluated in healthy subjects the feasibility of using MEA to monitor platelet inhibition of P2Y12 antagonists (clopidogrel in vivo, cangrelor in vitro and aspirin (100 mg per day in vivo, and 1 mM or 5.4 mM in vitro alone, and in combination. Statistical analyses were performed by the Mann-Whitney rank sum test, student' t-test, analysis of variance followed by the Holm-Sidak test, where appropriate. Results ADP-induced platelet aggregation in hirudin-anticoagulated blood was inhibited by 99.3 ± 1.4% by in vitro addition of cangrelor (100 nM; p 95% and 100 ± 3.2%, respectively (p in vitro or ex vivo. Oral intake of clopidogrel did not significantly reduce AA-induced aggregation, but P2Y12 blockade by cangrelor (100 nM in vitro diminished AA-stimulated aggregation by 53 ± 26% (p Conclusions Selective platelet inhibition by aspirin and P2Y12 antagonists alone and in combination can be rapidly measured by MEA. We suggest that dual anti-platelet therapy with these two types of anti-platelet drugs can be optimized individually by measuring platelet responsiveness to ADP and AA with MEA before and after drug intake.

  3. Study of the spheronization process of glass particles by the gravitational falling process for internal selective radiotherapy; Estudo do processo de esferolizacao por queda gravitacional de particulas vitreas visando a aplicacao em radioterapia interna seletiva

    Energy Technology Data Exchange (ETDEWEB)

    Barros Filho, E.C.; Martinelli, J.R., E-mail: eraldo.filho@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Sene, F.F. [Centro Tecnologico da Marinha em Sao Paulo (CTMS), Sao Paulo, SP (Brazil)

    2011-07-01

    The internal selective radiotherapy is an alternative to treat hepatocellular carcinoma. Glass microspheres containing β{sup -} emitter radionuclide are introduced in the liver, and they are housed preferentially in the region where the cancer cells are located. The microspheres are trapped in the arterioles which feed the tumors, and the β{sup -} particles annihilate the cancer cells. The glass particles must be spherical to avoid unnecessary bleeding, and the particle size must be restricted to a range which optimizes the blocking effect and avoid the migration to other parts of the human body. The particle size distribution of microspheres is not easily predicted since the variation of the aspect ratio and the presence of agglomerates can influence the resulting particle size distribution. In the present work, the spheronization process to obtain microspheres from irregular shape glass particles with suitable diameter and shape for radiotherapy treatment is studied. (author)

  4. Real-time monitoring of nitric oxide (NO) and pO2 levels under ischemic conditions associated with small bowel ischemia/reperfusion injury using selective electrodes for NO and oxygen molecules.

    Science.gov (United States)

    Watanabe, T; Owada, S; Kobayashi, H; Ishiuchi, A; Nakano, H; Asakuta, T; Shimamura, T; Asano, T; Koizumi, S; Jinnouchi, Y; Katayama, M; Kamibayasi, M; Murakami, E; Otsubo, T

    2007-12-01

    The present study demonstrated the feasibility of monitoring nitric oxide (NO) and pO2 levels under ischemic conditions associated with small bowel ischemia/reperfusion (I/R) injury through the use of selective electrodes for NO and oxygen molecules. NO levels gradually increased during ischemia. When reperfusion was started, the NO level decreased suddenly and returned to pre-ischemia values within 10 minutes. After clamping, pO2 decreased rapidly. When reperfusion was started, pO2 increased suddenly, returning to pre-ischemia values within 10 minutes. We concluded that it is feasible to monitor NO and pO2 levels under ischemic conditions of small bowel I/R injury through the use of electrodes selective for NO and oxygen molecules.

  5. Lid heater for glass melter

    International Nuclear Information System (INIS)

    Phillips, T.D.

    1993-01-01

    A glass melter having a lid electrode for heating the glass melt radiantly. The electrode comprises a series of INCONEL 690 tubes running above the melt across the melter interior and through the melter walls and having nickel cores inside the tubes beginning where the tubes leave the melter interior and nickel connectors to connect the tubes electrically in series. An applied voltage causes the tubes to generate heat of electrical resistance for melting frit injected onto the melt. The cores limit heat generated as the current passes through the walls of the melter. Nickel bus connection to the electrical power supply minimizes heat transfer away from the melter that would occur if standard copper or water-cooled copper connections were used between the supply and the INCONEL 690 heating tubes. 3 figures

  6. Correction: Cecotti, H. and Rivet, B. Subject Combination and Electrode Selection in Cooperative Brain-Computer Interface Based on Event Related Potentials. Brain Sci. 2014, 4, 335–355

    Directory of Open Access Journals (Sweden)

    Hubert Cecotti

    2014-09-01

    Full Text Available The authors wish to make the following correction to this paper (Cecotti, H.; Rivet, B. Subject Combination and Electrode Selection in Cooperative Brain-Computer Interface Based on Event Related Potentials. Brain Sci. 2014, 4, 335–355: Due to an internal error, the reference numbers in the original published paper were not shown, and the error was not due to the authors. The former main text should be replaced as below.

  7. Electrode Processes in Porous Electrodes.

    Science.gov (United States)

    1985-11-26

    F104470 2.0 MASS SPECTROMETRY One part of activity for this year is an investigation of the behavior of silver electrodes through the distribution of...al. (2)). These, in some cases, involve tedious and time comsuming procedures and discrepencies of as much as 15% have been observed in the results. As

  8. Detection of irradiated foods with the photo-stimulated luminescence technique. Selection of a glass fiber filter for evaluating the performance of the PSL detectors

    International Nuclear Information System (INIS)

    Sekiguchi, Masayuki; Yamazaki, Masao; Goto, Michiko

    2008-01-01

    The PSL method is useful as a screening technique of irradiated foods to support efficient uses of TL analysis. Recently, there has been the growing need for the system check or calibration using the standard materials with spread of domestically -produced PSL detector. In this research, we characterized the PSL of several types of glass fiber filters and compared the cumulate photon counts of a selected filter of them (GA-100) with those of the SUERC paprika standard for PSL measurements. GA-100 filter showed a linear relationship between cumulate photon counts and irradiation doses, and the cumulate photon counts in the first 2 months after gamma rays irradiation (261Gy) were markedly decreased and reduced to about 5000 counts (the upper threshold of PSL) after 4 months. However, further long-term storage and dose increase was necessary to produce the filter with more adequate PSI property as a standard material. Light exposure (630Lux) within 3 minutes to GA-100 had little effect on the cumulate photon counts. GA-100 showed relatively less variation in cumulate photon counts compared with the paprika standard in a series of studies. (author)

  9. Selective laser melting of an Al86Ni6Y4.5Co2La1.5 metallic glass: Processing, microstructure evolution and mechanical properties

    International Nuclear Information System (INIS)

    Li, X.P.; Kang, C.W.; Huang, H.; Zhang, L.C.; Sercombe, T.B.

    2014-01-01

    In this study, single line scans at different laser powers were carried out using selective laser meting (SLM) equipment on a pre-fabricated porous Al 86 Ni 6 Y 4.5 Co 2 La 1.5 metallic glass (MG) preform. The densification, microstructural evolution, phase transformation and mechanical properties of the scan tracks were systematically investigated. It was found that the morphology of the scan track was influenced by the energy distribution of the laser beam and the heat transfer competition between convection and conduction in the melt pool. Due to the Gaussian distribution of laser energy and heat transfer process, different regions of the scan track experienced different thermal histories, resulting in a gradient microstructure and mechanical properties. Higher laser powers caused higher thermal stresses, which led to the formation of cracks; while low power reduced the strength of the laser track, also inducing cracking. The thermal fluctuation at high laser power produced an inhomogeneous chemical distribution which gave rise to severe crystallization of the MG, despite the high cooling rate. The crystallization occurred both within the heat affected zone (HAZ) and at the edge of melt pool. However, by choosing an appropriate laser power crack-free scan tracks could be produced with no crystallization. This work provides the necessary fundamental understanding that will lead to the fabrication of large-size, crack-free MG with high density, controllable microstructure and mechanical properties using SLM

  10. Vacuum-free, maskless patterning of Ni electrodes by laser reductive sintering of NiO nanoparticle ink and its application to transparent conductors.

    Science.gov (United States)

    Lee, Daeho; Paeng, Dongwoo; Park, Hee K; Grigoropoulos, Costas P

    2014-10-28

    We introduce a method for direct patterning of Ni electrodes through selective laser direct writing (LDW) of NiO nanoparticle (NP) ink. High-resolution Ni patterns are generated from NiO NP thin films by a vacuum-free, lithography-free, and solution-processable route. In particular, a continuous wave laser is used for the LDW reductive sintering of the metal oxide under ambient conditions with the aid of reducing agents in the ink solvent. Thin (∼ 40 nm) Ni electrodes of glossy metallic surfaces with smooth morphology and excellent edge definition can be fabricated. By applying this method, we demonstrate a high transmittance (>87%), electrically conducting panel for a touch screen panel application. The resistivity of the Ni electrode is less than an order of magnitude higher compared to that of the bulk Ni. Mechanical bending test, tape-pull test, and ultrasonic bath test confirm the robust adhesion of the electrodes on glass and polymer substrates.

  11. GLASS BOX

    National Research Council Canada - National Science Library

    Curtis, Laura

    2008-01-01

    The goals of this effort were to develop Glass Box capabilities to allow for the capturing of analyst activities and the associated data resources, track and log the results of automated processing...

  12. A solid-contact Pb{sup 2+}-selective electrode using poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) as ion-to-electron transducer

    Energy Technology Data Exchange (ETDEWEB)

    Yu Shunyang [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Li Fuhai [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Chemistry and Chemical Engineering College, Yantai University, Yantai 264005 (China); Yin Tanji [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Liu Yongming [Chemistry and Chemical Engineering College, Yantai University, Yantai 264005 (China); Pan, Dawei [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Qin Wei, E-mail: wqin@yic.ac.cn [CAS and Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China)

    2011-09-30

    Highlights: {yields} All reagents used for the electrodes preparation were commercially available. {yields} The lower detection limit of the proposed electrode reached subnanomolar levels. {yields} No water film was observed with conventional commercially available PVC ion-sensing membranes. {yields} This research provides an excellent strategy for fabrication of robust polymeric ion sensors. - Abstract: In this work, a novel all-solid-state polymeric membrane Pb{sup 2+}-selective electrode was developed by using for the first time poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) (MEH-PPV) as solid contact. To demonstrate the ion-to-electron transducing ability of MEH-PPV, chronopotentiometry and electrochemical impedance spectroscopy measurements were carried out. The proposed electrodes showed a Nernstian response of 29.1 mV decade{sup -1} and a lower detection limit of subnanomolar level. No water film was observed with the conventional plasticized PVC membrane. This work demonstrates a new strategy for the fabrication of robust potentiometric ion sensors.

  13. Spinal cord electrophysiology II: extracellular suction electrode fabrication.

    Science.gov (United States)

    Garudadri, Suresh; Gallarda, Benjamin; Pfaff, Samuel; Alaynick, William

    2011-02-20

    Development of neural circuitries and locomotion can be studied using neonatal rodent spinal cord central pattern generator (CPG) behavior. We demonstrate a method to fabricate suction electrodes that are used to examine CPG activity, or fictive locomotion, in dissected rodent spinal cords. The rodent spinal cords are placed in artificial cerebrospinal fluid and the ventral roots are drawn into the suction electrode. The electrode is constructed by modifying a commercially available suction electrode. A heavier silver wire is used instead of the standard wire given by the commercially available electrode. The glass tip on the commercial electrode is replaced with a plastic tip for increased durability. We prepare hand drawn electrodes and electrodes made from specific sizes of tubing, allowing consistency and reproducibility. Data is collected using an amplifier and neurogram acquisition software. Recordings are performed on an air table within a Faraday cage to prevent mechanical and electrical interference, respectively.

  14. Development of a ceramic membrane from a lithian spinel, Li1+xMyMn2-yO4 (M=trivalent or tetravalent cations) for a Li ion-selective electrode

    Science.gov (United States)

    Yoon, H.; Venugopal, N.; Rim, T.; Yang, B.; Chung, K.; Ko, T.

    2010-12-01

    Recently a few lithium containing ceramics are reported as promising cathodes for application in lithium batteries. Among them, a spinel-type lithium manganate (LM) exhibits an exceptionally high ion selectivity at room temperature. Thus, LM could have a great potential as an ion selective membrane material for screening interfering ions from lithium ion for the determination of lithium ion in salt solution. In this study, we developed an ion-selective electrode based on LM as a membrane material and investigated its lithium ion selectivity by varying the content of M in composition. A sol-gel process was successfully applied for preparing LM films without resorting to calcination at a high temperature. The LM thin film-type membranes exhibit a high selectivity for Li ion over other cations, a wide operation detection range of 10-5 ~ 10-2 M, and a fast response time less than 60 s. Furthermore, our result demonstrates a linear potentiometric response over a wide range of lithium concentration, which is compared to that of a lithium ion-selective electrode based on an ionophore. Acknowledgements: This research was supported by a grant from the Development of Technology for Extraction of Resources Dissolved in Sea Water Program funded by Ministry of Land Transport and Maritime Affairs in Korean Government (2010).

  15. Application of electrical resistance tomography to glass melter

    International Nuclear Information System (INIS)

    Ichijo, Noriaki; Sakai, Taiji; Fujiwara, Hiroaki; Matsuno, Shinsuke; Misumi, Ryuta; Nishi, Kazuhiko; Kaminoyama, Meguru

    2015-01-01

    This paper describes the application of electrical resistance tomography (ERT) to glass melter to monitor the accumulation of the noble metals. To minimize the modification of the melter, existing structures such as thermowells and heating electrodes are used as electrodes of ERT, and the number of electrodes is much fewer than the conventional method. Therefore, Expanding Combination Data Acquisition method (ECDA) is developed and applies to the glass melter. ECDA method uses adjacent method and opposite method as a data acquisition and current injection electrodes are used as voltage measurement electrodes to increase the number of the data. In addition, conductivity images are reconstructed only near the wall to improve the resolution. As a result of applying to the glass melter, the conductivity change inside the melter caused by temperature can be monitored. Furthermore, lower voltage is measured in case of containing the noble metals inside the melter. Therefore, the potential as a monitoring method be confirmed. (author)

  16. Glass Formulation Development for INEEL Sodium-Bearing Waste

    International Nuclear Information System (INIS)

    Vienna, J.D.; Schweiger, M.J.; Smith, D.E.; Smith, H.D.; Crum, J.V.; Peeler, D.K.; Reamer, I.A.; Musick, C.A.; Tillotson, R.D.

    1999-01-01

    For about four decades, radioactive wastes have been collected and calcined from nuclear fuels reprocessing at the Idaho Nuclear Technology and Engineering Center (INTEC), formerly Idaho Chemical Processing Plant (ICPP). Over this time span, secondary radioactive wastes have also been collected and stored as liquid from decontamination, laboratory activities, and fuel-storage activities. These liquid wastes are collectively called sodium-bearing wastes (SBW). About 5.7 million liters of these wastes are temporarily stored in stainless steel tanks at the Idaho National Engineering and Environmental Laboratory (INEEL). Vitrification is being considered as an immobilization step for SBW with a number of treatment and disposal options. A systematic study was undertaken to develop a glass composition to demonstrate direct vitrification of INEEL's SBW. The objectives of this study were to show the feasibility of SBW vitrification, not a development of an optimum formulation. The waste composition is relatively high in sodium, aluminum, and sulfur. A specific composition and glass property restrictions, discussed in Section 2, were used as a basis for the development. Calculations based on first-order expansions of selected glass properties in composition and some general tenets of glass chemistry led to an additive (fit) composition (68.69 mass % SiO 2 , 14.26 mass% B 2 O 3 , 11.31 mass% Fe 2 O 3 , 3.08 mass% TiO 2 , and 2.67 mass % Li 2 O) that meets all property restrictions when melted with 35 mass % of SBW on an oxide basis, The glass was prepared using oxides, carbonates, and boric acid and tested to confirm the acceptability of its properties. Glass was then made using waste simulant at three facilities, and limited testing was performed to test and optimize processing-related properties and confirm results of glass property testing. The measured glass properties are given in Section 4. The viscosity at 1150 C, 5 Pa·s, is nearly ideal for waste-glass processing in

  17. Nanopatterned Bulk Metallic Glass Biosensors.

    Science.gov (United States)

    Kinser, Emily R; Padmanabhan, Jagannath; Yu, Roy; Corona, Sydney L; Li, Jinyang; Vaddiraju, Sagar; Legassey, Allen; Loye, Ayomiposi; Balestrini, Jenna; Solly, Dawson A; Schroers, Jan; Taylor, André D; Papadimitrakopoulos, Fotios; Herzog, Raimund I; Kyriakides, Themis R

    2017-12-22

    Nanopatterning as a surface area enhancement method has the potential to increase signal and sensitivity of biosensors. Platinum-based bulk metallic glass (Pt-BMG) is a biocompatible material with electrical properties conducive for biosensor electrode applications, which can be processed in air at comparably low temperatures to produce nonrandom topography at the nanoscale. Work presented here employs nanopatterned Pt-BMG electrodes functionalized with glucose oxidase enzyme to explore the impact of nonrandom and highly reproducible nanoscale surface area enhancement on glucose biosensor performance. Electrochemical measurements including cyclic voltammetry (CV) and amperometric voltammetry (AV) were completed to compare the performance of 200 nm Pt-BMG electrodes vs Flat Pt-BMG control electrodes. Glucose dosing response was studied in a range of 2 mM to 10 mM. Effective current density dynamic range for the 200 nm Pt-BMG was 10-12 times greater than that of the Flat BMG control. Nanopatterned electrode sensitivity was measured to be 3.28 μA/cm 2 /mM, which was also an order of magnitude greater than the flat electrode. These results suggest that nonrandom nanotopography is a scalable and customizable engineering tool which can be integrated with Pt-BMGs to produce biocompatible biosensors with enhanced signal and sensitivity.

  18. Emerging Transparent Conducting Electrodes for Organic Light Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Tze-Bin Song

    2014-03-01

    Full Text Available Organic light emitting diodes (OLEDs have attracted much attention in recent years as next generation lighting and displays, due to their many advantages, including superb performance, mechanical flexibility, ease of fabrication, chemical versatility, etc. In order to fully realize the highly flexible features, reduce the cost and further improve the performance of OLED devices, replacing the conventional indium tin oxide with better alternative transparent conducting electrodes (TCEs is a crucial step. In this review, we focus on the emerging alternative TCE materials for OLED applications, including carbon nanotubes (CNTs, metallic nanowires, conductive polymers and graphene. These materials are selected, because they have been applied as transparent electrodes for OLED devices and achieved reasonably good performance or even higher device performance than that of indium tin oxide (ITO glass. Various electrode modification techniques and their effects on the device performance are presented. The effects of new TCEs on light extraction, device performance and reliability are discussed. Highly flexible, stretchable and efficient OLED devices are achieved based on these alternative TCEs. These results are summarized for each material. The advantages and current challenges of these TCE materials are also identified.

  19. Effect of material, process parameters, and simulated body fluids on mechanical properties of 13-93 bioactive glass porous constructs made by selective laser sintering.

    Science.gov (United States)

    Kolan, Krishna C R; Leu, Ming C; Hilmas, Gregory E; Velez, Mariano

    2012-09-01

    The effect of particle size distribution, binder content, processing parameters, and sintering schedule on the microstructure and mechanical properties of porous constructs was investigated. The porous constructs were produced by indirect selective laser sintering (SLS) of 13-93 bioactive glass using stearic acid as a polymeric binder. The binder content and d(50) particle size in the feedstock powders were simultaneously reduced from 22 to 12 wt% and from 20 to 11 μm, respectively, to identify the minimum binder content required for the SLS fabrication. An average particle size of ∼16 μm with a binder content of 15 wt% significantly reduced post-processing time and improved mechanical properties. Increasing the laser power and scan speed at the energy density of 1 cal/cm² maintained the feature sharpness of the parts during the fabrication of green parts and could almost double the mechanical properties of the sintered parts. Changes in the heating rates, ranging from 0.1 to 2 °C/min, during the post-processing of the fabricated "green" scaffolds showed that the heating rate significantly affects the densification and mechanical properties of the sintered scaffolds. The compressive strength of the scaffolds manufactured with the optimized parameters varied from 41 MPa, for a scaffold with a porosity of ∼50%, to 157 MPa, for a dense part. The bioactive scaffolds soaked in simulated body fluids for durations up to 6 weeks were used to evaluate the change in mechanical properties in vitro. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Glass compositions

    Energy Technology Data Exchange (ETDEWEB)

    France, P W

    1985-05-30

    A fluoride glass for use in the production of optical fibres has an enhanced D/H ratio, preferably such that OD:OH is at least 9:1. In the example, such a glass is prepared by treating with D/sub 2/O a melt comprising 51.53 mole per cent ZrF/sub 4/, 20.47 mole per cent BaF/sub 2/, 5.27 mole per cent LaF/sub 3/, 3.24 mole per cent AlF/sub 3/, and 19.49 mole per cent LiF.

  1. Development of a pH sensing membrane electrode based on a new calix[4]arene derivative.

    Science.gov (United States)

    Kormalı Ertürün, H Elif; Demirel Özel, Ayça; Sayın, Serkan; Yılmaz, Mustafa; Kılıç, Esma

    2015-01-01

    A new pH sensing poly(vinyl chloride) (PVC) membrane electrode was developed by using recently synthesized 5,17-bis(4-benzylpiperidine-1-yl)methyl-25,26,27,28-tetrahydroxy calix[4]arene as an ionophore. The effects of membrane composition, inner filling solution and conditioning solution on the potential response of the proposed pH sensing membrane electrode were investigated. An optimum membrane composition of 3% ionophore, 67% o-nitrophenyl octyl ether (o-NPOE) as plasticizer, 30% PVC was found. The electrode exhibited a near-Nernstian slope of 58.7±1.1 mV pH(-1) in the pH range 1.9-12.7 at 20±1 °C. It showed good selectivity for H(+) ions in the presence of some cations and anions and a longer lifetime of at least 12 months when compared with the other PVC membrane pH electrodes reported in the literature. Having a wide working pH range, it was not only applied as a potentiometric indicator electrode in various acid-base titrations, but also successfully employed in different real samples. It has good reproducibility and repeatability with a response time of 6-7s. Compared to traditional glass pH electrode, it exhibited excellent potentiometric response after being used in fluoride-containing media. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Effect of Gamma Irradiation on Some Properties of Bismuth Silicate Glasses and Their Glass Derivatives

    International Nuclear Information System (INIS)

    Abo Hussein, E.M.K.

    2014-01-01

    Glasses containing bismuth oxide have attracted considerable attention, although it is non-conventional glass forming oxide, but it has wide applications. In this work, it is aimed to prove that bismuth silicate glass can act as a good shielding material for γ- rays. For this purpose glass containing 20% bismuth oxide and 80% SiO_2 was prepared using melting-annealing technique. Also effects of adding some alkali heavy metal oxides to this glass such as PbO, BaO or SrO were also studied. The formed glasses were also heat treated at 450 degree C for 4 hours to give the corresponding heat treated glasses. Electron Paramagnetic Resonance (EPR) measurements show that the prepared glasses and heat treated glasses have very good stability when exposed to γ- irradiation, which encourage the assumption of using these glasses as gamma ray shielding materials. Many properties have been investigated, such as density to understand the structural properties, also mechanical properties were verified by measuring microhardness, while the chemical resistance was identified by testing their durability in both acidic and basic solutions. The EPR results were supported by measuring electrical conductivity of the glass and heat treated glass samples at different temperatures ranging from 298 to 553 K, which proved that these glasses have very low conductivity even at high temperature. The formed phases of heat treated glass or glass ceramic samples were demonstrated by means of X-ray diffraction (XRD). Also studying the structure of glasses and heat treated glasses before and after irradiation was investigated by the Infrared transmitting spectra. Calculations of optical band gap energies were demonstrated for some selected glasses and heat treated glasses from the data of UV optical absorption spectra to support the probability of using these bismuth silicate glasses for gamma radiation shielding processing.

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

    Science.gov (United States)

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

    2013-09-17

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

  4. Synthesis and characterization of poly-o-anisidine Sn(IV tungstate: A new and novel ‘organic–inorganic’ nano-composite material and its electro-analytical applications as Hg(II ion-selective membrane electrode

    Directory of Open Access Journals (Sweden)

    Asif A. Khan

    2012-07-01

    Full Text Available An organic–inorganic nano-composite poly-o-anisidine Sn(IV tungstate was chemically synthesized by sol–gel mixing of the incorporation of organic polymer o-anisidine into the matrices of inorganic ppt of Sn(IV tungstate in different mixing volume ratios. This composite material has been characterized using various analytical techniques like XRD (X-ray diffraction, FTIR (Fourier transform infrared, SEM (Scanning electron microscopy, TEM (Transmission electron microscopy and simultaneous TGA (Thermogravimetric analysis studies. On the basis of distribution studies, the material was found to be highly selective for Hg(II. Using this nano-composite cation exchanger as electro-active material, a new heterogeneous precipitate based on ion-sensitive membrane electrode was developed for the determination of Hg(II ions in solutions. The membrane electrode was mechanically stable, with a quick response time, and can be operated within a wide pH range. The electrode was also found to be satisfactory in electrometric titrations.

  5. Manual and Flow-Injection Detection/Quantification of Polyquaterniums via Fully Reversible Polyion-Sensitive Polymeric Membrane-Based Ion-Selective Electrodes.

    Science.gov (United States)

    Ferguson, Stephen A; Meyerhoff, Mark E

    2017-10-27

    The detection of four different polyquaterniums (PQs) using a fully reversible potentiometric polyion sensor in three different detection modes is described. The polyion sensing "pulstrodes" serve as the detector for direct dose-response experiments, beaker titrations, and in a flow-injection analysis (FIA) system. Direct polycation response toward PQ-2, PQ-6, PQ-10, and poly(2-methacryloxyethyltrimethylammonium) chloride (PMETAC) yields characteristic information about each PQ species (e.g., relative charge densities, etc.) via syringe pump addition of each PQ species to a background electrolyte solution. Quantitative titrations are performed using a syringe pump to deliver heparin as the polyanion titrant to quantify all four PQs at μg/mL levels. Both the direct and indirect methods incorporate the use of a three-electrode system including counter, double junction reference, and working electrodes. The working electrode possesses a plasticized poly(vinyl chloride) (PVC) membrane containing the neutral lipophilic salt of dinonylnaphthalenesulfonate (DNNS - ) tridodecylmethylammonium (TDMA + ). Further, the titration method is shown to be useful to quantify PQ-6 levels in recreational swimming pool water collected in Ann Arbor, MI. Finally, a FIA system equipped with a pulstrode detector is used to demonstrate the ability to potentially quantify PQ levels via a more streamlined and semiautomated testing platform.

  6. Ternary semitransparent organic solar cells with a laminated top electrode.

    Science.gov (United States)

    Makha, Mohammed; Testa, Paolo; Anantharaman, Surendra Babu; Heier, Jakob; Jenatsch, Sandra; Leclaire, Nicolas; Tisserant, Jean-Nicolas; Véron, Anna C; Wang, Lei; Nüesch, Frank; Hany, Roland

    2017-01-01

    Tinted and colour-neutral semitransparent organic photovoltaic elements are of interest for building-integrated applications in windows, on glass roofs or on facades. We demonstrate a semitransparent organic photovoltaic cell with a dry-laminated top electrode that achieves a uniform average visible transmittance of 51% and a power conversion efficiency of 3%. The photo-active material is based on a majority blend composed of a visibly absorbing donor polymer and a fullerene acceptor, to which a selective near-infrared absorbing cyanine dye is added as a minority component. Our results show that organic ternary blends are attractive for the fabrication of semitransparent solar cells in general, because a guest component with a complementary absorption can compensate for the inevitably reduced current generation capability of a high-performing binary blend when applied as a thin, semitransparent film.

  7. Booted selective internal radiation therapy (B-SIRT) using 90Y-loaded glass microspheres induces prolonged overall survival for PVT patients

    International Nuclear Information System (INIS)

    Garin, E.; Lenoir, L.; Edeline, J.; Laffont, S.; Mesbah, H.; Poree, P.; Boucher, E.; Rolland, Y.

    2015-01-01

    Full text of publication follows. Goal: evaluation of the response rate and survival of hepatocellular carcinoma PVT patients treated with Therasphere using the boost concept. Material and methods: Therasphere was administered in 40 PVT hepatocellular carcinoma patients (main = 11, lobar = 23, segmental = 6). MAA SPECT/CT quantitative analysis was used for the calculation of the tumour dose (TD), the healthy injected liver dose (HLD) and the injected liver dose (LD). Response was evaluated at 3 months using EASL criterion. OS was evaluated using Kaplan and Meyer tests. Results: Mean 90 Y-loaded microspheres injected activity was 3.1 ± 1.5 GBq. Mean LD was 143 ± 49 Gy. Median TD was 316 Gy for responding lesions versus 133 Gy for non responding lesion (p<0.0001). With a threshold TD of 205 Gy, MAA-SPECT/CT was predictive of response with a sensibility of 100%, and an overall accuracy of 90% (0FN, 4FP). Knowing the TD and the HLD, 40% of the patients received an intensification of the treatment (increase of the injected activity with the goal to achieve a TD> 205 Gy with a LD > 150 Gy and a HLD<120 Gy) with a good response rate (81%) and without increased liver grade III toxicity (6.2% as against 12.5% in the non boosted patients, ns). 6 patients were put aside, 5 received a lobar hepatectomy. Median OS was 18.2 months [12-27]. It was 4 m [12-27] for patients with a TD < 205 Gy versus 21.5 m [12-28.5] for patients with a TD > 205 Gy. OS was 12 m [3-∞] for patients with main PVT versus 21.5 m [12-28.7] for patients segmental or lobar PVT (ns). Finally Os was 23.2 m for patients with a TD > 205 Gy and a good PVT targeting (n = 34). Conclusion: boosted selective internal radiation therapy using 90 Y-loaded glass microspheres induces prolonged overall survival for PVT patients without increasing liver toxicity. (authors)

  8. Glass: Rotary Electric Glass Furnace

    Energy Technology Data Exchange (ETDEWEB)

    Recca, L.

    1999-01-29

    Compared to conventional gas-fired furnaces, the new rotary electric furnace will increase energy efficiency while significantly reducing air emissions, product turnaround time, and labor costs. As this informative new fact sheet explains, the thousand different types of glass optical blanks produced for the photonics industry are used for lasers, telescopes, cameras, lights, and many other products.

  9. Spatially selective Au nanoparticle growth in laser-quality glass controlled by UV-induced phosphate-chain cross-linkage

    International Nuclear Information System (INIS)

    Sigaev, Vladimir N; Savinkov, Vitaly I; Lotarev, Sergey V; Shakhgildyan, Georgiy Yu; Paleari, Alberto; Lorenzi, Roberto

    2013-01-01

    Herein we describe how UV excitation of localized electronic states in phosphate glasses can activate structural rearrangements that influence the kinetics of Au nanoparticle (NP) thermal growth in Au-doped glass. The results suggest a novel strategy to address the problem of controlling nano-assembly processes of metal NP patterns in fully inorganic and chemically stable hard materials, such as laser-quality glasses. We show that the mechanism is promoted by opening and subsequent cross-linkage of phosphate chains under UV excitation of non-bridging groups in the amorphous network of the glass, with a consequent modification of Au diffusion and metal NP growth. Importantly, the micro-Raman mapping of the UV-induced modifications demonstrates that the process is restricted within the beam waist region of the focused UV laser beam. This fact is consistent with the need for more than one excitation event, close in time and in space, in order to promote structural cross-linkage and Au diffusion confinement. The stability of the photo-induced modifications makes it possible to design new metal patterning approaches for the fabrication of three-dimensional metal structures in laser-quality materials for high-power nonlinear applications. (paper)

  10. Spatially selective Au nanoparticle growth in laser-quality glass controlled by UV-induced phosphate-chain cross-linkage.

    Science.gov (United States)

    Sigaev, Vladimir N; Savinkov, Vitaly I; Lotarev, Sergey V; Shakhgildyan, Georgiy Yu; Lorenzi, Roberto; Paleari, Alberto

    2013-06-07

    Herein we describe how UV excitation of localized electronic states in phosphate glasses can activate structural rearrangements that influence the kinetics of Au nanoparticle (NP) thermal growth in Au-doped glass. The results suggest a novel strategy to address the problem of controlling nano-assembly processes of metal NP patterns in fully inorganic and chemically stable hard materials, such as laser-quality glasses. We show that the mechanism is promoted by opening and subsequent cross-linkage of phosphate chains under UV excitation of non-bridging groups in the amorphous network of the glass, with a consequent modification of Au diffusion and metal NP growth. Importantly, the micro-Raman mapping of the UV-induced modifications demonstrates that the process is restricted within the beam waist region of the focused UV laser beam. This fact is consistent with the need for more than one excitation event, close in time and in space, in order to promote structural cross-linkage and Au diffusion confinement. The stability of the photo-induced modifications makes it possible to design new metal patterning approaches for the fabrication of three-dimensional metal structures in laser-quality materials for high-power nonlinear applications.

  11. HVDC Ground Electrodes and Tectonic Setting

    Science.gov (United States)

    Freire, P. F.; Pereira, S. Y.

    2017-12-01

    Ground electrodes in HVDC transmission are huge grounding systems for the DC part of the converter substation, about 1 km wide, sized to inject in the ground DC currents up to 3.5 kA. This work presents an analysis of how the tectonic setting at converter substation location is determinant for the search of the best electrode location (Site Selection) and on its design and performance. It will briefly present the author experience on HVDC electrode design, summarized as follows: Itaipu - Foz do Iguaçu electrodes (transmitter side) located in the middle of Paraná Sedimentary Basin, and Ibiúna electrodes (receiving side) on the border of the basin, 6 km from the geological strike, where the crystalline basement outcrops in São Paulo state; Madeira River - North electrodes (transmitting side) located on the Northwest border of South Amazon Craton, where the crystalline basement is below a shallow sediments layer, and South electrodes (receiving side) located within Paraná Sedimentary Basin; Chile - electrodes located on the Andean forearc, where the Nazca Plate plunges under the South American Plate; Kenya - Ethiopia - electrodes located in the African Rift; Belo Monte - North electrodes (transmitter side) located within the Amazonian Sedimentary Basin, about 35 km of its South border, and South electrodes (receiving side) within Paraná Sedimentary Basin (bipole 1) and on crystalline metamorphic terrain "Brasília Belt" (bipole 2). This diversity of geological conditions results on ground electrodes of different topologies and dimensions, with quite different electrical and thermal performances. A brief study of the geology of the converter stations regions, the so-called Desktop Study, allows for the preview of several important parameters for the site selection and design of the electrodes, such as localization, type, size and estimate of the interference area, which are important predictors of the investment to be made and indications of the design to be

  12. Polymer Coatings of Cochlear Implant Electrode Surface - An Option for Improving Electrode-Nerve-Interface by Blocking Fibroblast Overgrowth.

    Directory of Open Access Journals (Sweden)

    C Hadler

    Full Text Available Overgrowth of connective tissue and scar formation induced by the electrode array insertion increase the impedance and, thus, diminish the interactions between neural probes as like cochlear implants (CI and the target tissue. Therefore, it is of great clinical interest to modify the carrier material of the electrodes to improve the electrode nerve interface for selective cell adhesion. On one side connective tissue growth needs to be reduced to avoid electrode array encapsulation, on the other side the carrier material should not compromise the interaction with neuronal cells. The present in vitro-study qualitatively and quantitatively characterises the interaction of fibroblasts, glial cells and spiral ganglion neurons (SGN with ultrathin poly(N,N-dimethylacrylamide (PDMAA, poly(2-ethyloxazoline (PEtOx and poly([2-methacryloyloxyethyl]trimethylammoniumchlorid (PMTA films immobilised onto glass surfaces using a photoreactive anchor layer. The layer thickness and hydrophilicity of the polymer films were characterised by ellipsometric and water contact angle measurement. Moreover the topography of the surfaces was investigated using atomic force microscopy (AFM. The neuronal and non-neuronal cells were dissociated from spiral ganglions of postnatal rats and cultivated for 48 h on top of the polymer coatings. Immunocytochemical staining of neuronal and intermediary filaments revealed that glial cells predominantly attached on PMTA films, but not on PDMAA and PEtOx monolayers. Hereby, strong survival rates and neurite outgrowth were only found on PMTA, whereas PDMAA and PEtOx coatings significantly reduced the SG neuron survival and neuritogenesis. As also shown by scanning electron microscopy (SEM SGN strongly survived and retained their differentiated phenotype only on PMTA. In conclusion, survival and neuritogenesis of SGN may be associated with the extent of the glial cell growth. Since PMTA was the only of the polar polymers used in this study

  13. Molecularly imprinted polyaniline-ferrocene-sulfonic acid-Carbon dots modified pencil graphite electrodes for chiral selective sensing of D-Ascorbic acid and L-Ascorbic acid: A clinical biomarker for preeclampsia

    International Nuclear Information System (INIS)

    Pandey, Indu; Jha, Shashank Shekhar

    2015-01-01

    Highlights: • Pencil graphite electrode was non-covalently functionalized by C-dots. • Electrochemically synthesized ferrocene-sulfonic acid doped PANI film was used as chiral recognition element. • Electrochemical chiral sensing of L-ascorbic acid and D-ascorbic acid was carried out. • L-ascorbic acid determination was done in aqueous, biological and pharmaceutical samples at nM level. - Abstract: A simple and novel method is proposed for chiral separation of L-ascorbic acid and D-ascorbic acid in human cerebrospinal fluids and blood plasma samples. Electro-polymerized molecularly imprinted poly-aniline ferrocenesulfonic acid-C-dots modified pencil graphite electrodes was successfully applied for separation and quantification of D-/L-ascorbic acid in aqueous and some biological samples. Parameters, important to control the performance of the electrochemical sensor were investigated and optimized, including the effects of pH, monomer- template ratios, electropolymerization cycles and scan rates. The molecularly imprinted film exhibited a high chiral selectivity and sensitivity towards D-ascorbic acid and L-ascorbic acid respectively. The surface morphologies and electrochemical properties of the proposed sensor were characterized by scanning electron microscopy, cyclic voltammetry, difference pulse voltammetry, chrono-amperometry and electrochemical impedance spectroscopy. L-ascorbic acid selective sensor shows excellent selectivity towards the L-ascorbic acid in comparison to D- ascorbic acid vice versa for D- ascorbic acid selective sensor. Under optimal conditions the linear range of the calibration curve for L- ascorbic acid and D- ascorbic acid was 6.0–165.0 nM and 6.0–155.0 nM, with the detection limit of 0.001 nM and 0.002 nM. Chiral detection of L-ascorbic acid was successfully carried out in pharmaceuticals and human plasma samples (pregnant women and non pregnant women) via proposed sensor with good selectivity and sensitivity.

  14. Nitrate glass

    International Nuclear Information System (INIS)

    Kirilenko, I.A.; Vinogradov, E.E.

    1977-01-01

    Experimental evidence on behaviour of nitrate glasses is reviewed in terms of relationships between the presence of water in vitrescent nitrate systems and the properties of the systems. The glasses considered belong to systems of Mg(NO 3 ) 2 - Nd(NO 3 ) 3 ; Hg(NO 3 ) 2 -Nd(NO 3 ) 3 ; NaNO 3 -Mg(NO 3 ) 2 -Nd(NO 3 ) 3 ; M-Zn(NO 3 ) 3 , where M is a mixture of 20% mass NaNO 3 and 80% mass Mg(NO 3 ) 2 , and Zn is a rare earth ion. Nitrate glass is shown to be a product of dehydration. Vitrification may be regarded as a resusl of formation of molecular complexes in the chain due to hydrogen bonds of two types, i.e. water-water, or water-nicrate group. Chain formation, along with low melting points of the nitrates, hinder crystallization of nitrate melts. Provided there is enough water, this results in vitrification

  15. Light addressable gold electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Khalid, Waqas

    2011-07-01

    The main objective carried out in this dissertation was to fabricate Light Amplified Potentiometric sensors (LAPS) based upon the semiconductor nanoparticles (quantum dots) instead of its bulk form. Quantum dots (QDs) were opted for this device fabrication because of their superior fluorescent, electric and catalytic properties. Also in comparison to their bulk counterparts they will make device small, light weighted and power consumption is much lower. QDs were immobilized on a Au substrate via 1,4 benzene dithiol (BDT) molecule. Initially a self-assembled monolayer (SAM) of BDT was established on Au substrate. Because of SAM, the conductivity of Au substrate decreased dramatically. Furthermore QDs were anchored with the help of BDT molecule on Au substrate. When QDs immobilized on Au substrate (QD/Au) via BDT molecule were irradiated with UV-visible light, electron-hole pairs were generated in QDs. The surface defect states in QDs trapped the excited electrons and long lived electron-hole pairs were formed. By the application of an appropriate bias potential on Au substrate the electrons could be supplied or extracted from the QDs via tunneling through BDT. Thus a cathodic or anodic current could be observed depending upon bias potential under illumination. However without light illumination the QD/Au electrode remained an insulator. To improve the device different modifications were made, including different substrates (Au evaporated on glass, Au evaporated on mica sheets and Au sputtered on SiO{sub 2}/Si) and different dithiol molecules (capped and uncapped biphenyl 4,4' dithiol and capped and uncapped 4,4' dimercaptostilbenes) were tried. Also different QD immobilization techniques (normal incubation, spin coating, layer by layer assembly (LbL) of polyelectrolytes and heat immobilization) were employed. This device was able to detect electrochemically different analytes depending upon the QDs incorporated. For example CdS QDs were able to detect 4

  16. Glass pipette-carbon fiber microelectrodes for evoked potential recordings

    Directory of Open Access Journals (Sweden)

    Moraes M.F.D.

    1997-01-01

    Full Text Available Current methods for recording field potentials with tungsten electrodes make it virtually impossible to use the same recording electrode also as a lesioning electrode, for example for histological confirmation of the recorded site, because the lesioning procedure usually wears off the tungsten tip. Therefore, the electrode would have to be replaced after each lesioning procedure, which is a very high cost solution to the problem. We present here a low cost, easy to make, high quality glass pipette-carbon fiber microelectrode that shows resistive, signal/noise and electrochemical coupling advantages over tungsten electrodes. Also, currently used carbon fiber microelectrodes often show problems with electrical continuity, especially regarding electrochemical applications using a carbon-powder/resin mixture, with consequent low performance, besides the inconvenience of handling such a mixture. We propose here a new method for manufacturing glass pipette-carbon fiber microelectrodes with several advantages when recording intracerebral field potentials

  17. The use of in situ Fourier-transform infrared spectroscopy for the study of surface phenomena on electrodes in selected lithium battery electrolyte solutions

    Science.gov (United States)

    Aurbach, D.; Chusid, O.

    This paper presents some examples of surface studies of noble metals and Li electrodes in Li battery electrolyte solutions using in situ FT-IR spectroscopic techniques. These examples include the study of a mixture of solvents, the role of the reduction of salt in the build-up of surface films on the electrodes and the impact of contaminants such as traces of oxgen and water. The techniques included multiple and single internal reflectance modes and external reflectance (SNIFTIRS-type) mode. The following conclusions were drawn from this study: (i) salts containing the -SO 2CF 3 group are much more reactive on Li than LiAsF 6. Their reduction dominates the surface chemistry developed on Li in ethereal solutions; (ii) water reduction on Li in wet 1,3-dioxolane solution may not form stable LiOH films due to the further reaction of the hydroxy group with the solvent; (iii) in spite of its low solubility, oxygen dissolved in propylene carbonate and tetrahydrofuran solutions has some impact on the surface chemistry developed on Li in these solutions (probably due to Li 2O formation).

  18. Toward selective electrochemical 'E-tongue': Potentiometric DO sensor based on sub-micron ZnO-RuO{sub 2} sensing electrode

    Energy Technology Data Exchange (ETDEWEB)

    Zhuiykov, Serge, E-mail: serge.zhuiykov@csiro.au [CSIRO, Materials Science and Engineering Division, 37 Graham Road, Highett, VIC 3190 (Australia); Kats, Eugene [CSIRO, Materials Science and Engineering Division, 37 Graham Road, Highett, VIC 3190 (Australia); Plashnitsa, Vladimir [Research and Education Centre of Carbon Resources, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan); Miura, Norio [KASTEC, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan)

    2011-06-01

    Highlights: > We examine ZnO-doped RuO{sub 2} sensing electrode of DO sensor. > Study of ZnO-RuO{sub 2} confirmed the development of high surface-to-volume ratio. > Developed sensing electrode is insensitive to the presence of various dissolved salts. > 20 mol% ZnO-doped RuO{sub 2} sensing electrode enables maximum DO sensitivity. > We conclude that DO sensor based on ZnO-RuO{sub 2} electrode can work at 11-30 deg. C. - Abstract: Planar dissolved oxygen (DO) sensors based on thick-film ZnO-RuO{sub 2} sensing electrodes (SEs) with different mol% of ZnO were prepared on the alumina substrates using a screen-printing method and their structural and electrochemical properties were closely studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), electrochemical impedance spectroscopy (EIS) and energy-dispersive spectroscopy (EDS) techniques. Structural and electrochemical properties of ZnO-RuO{sub 2}-SEs have been investigated. Interference testing ascertained that the DO sensor based on sub-micron ZnO-RuO{sub 2}-SE is insensitive to the presence of various dissolved ions including Cl{sup -}, Li{sup +}, SO{sub 4}{sup 2-}, NO{sup 3-}, Ca{sup 2+}, PO{sub 4}{sup 3-}, Mg{sup 2+}, Na{sup +} and K{sup +} within a concentration range of 10{sup -7} to 10{sup -1} mol/L for DO measurement from 0.5 to 8.0 ppm in the test solution at a temperature range of 11-30 deg. C. These dissolved salts had practically no effect on the sensor's output potential difference response, whereas Br{sup -} ions had some effects at concentration more than 10{sup -3} mol/L. The relationship between DO and the sensor's potential difference was found to be relatively linear with the maximum sensitivity of -50.6 mV per decade was achieved at 20 mol% ZnO at 7.35 pH. The response and recovery time to pH changes for the planar device based on 20 mol% ZnO-RuO{sub 2}-SE was found to be 10 and 25 s

  19. Glass packages in interim storage

    International Nuclear Information System (INIS)

    Jacquet-Francillon, N.

    1994-10-01

    This report summarize the current state of knowledge concerning the behavior of type C waste packages consisting of vitrified high-level solutions produced by reprocessing spent fuel. The composition and the physical and chemical properties of the feed solutions are reviewed, and the vitrification process is described. Sodium alumino-borosilicate glass compositions are generally employed - the glass used at la Hague for LWR fuel solutions, for example, contains 45 % SiO 2 . The major physical, chemical, mechanical and thermal properties of the glass are reviewed. In order to allow their thermal power to diminish, the 3630 glass packages produced (as of January 1993) in the vitrification facilities at Marcoule and La Hague are placed in interim storage for several decades. The actual interim storage period has not been defined, as it is closely related to the concept and organization selected for the final destination of the packages: a geological repository. The glass behavior under irradiation is described. Considerable basic and applied research has been conducted to assess the aqueous leaching behavior of nuclear containment glass. The effects of various repository parameters (temperature, flow rate, nature of the environmental materials) have been investigated. The experimental findings have been used to specify a model describing the kinetics of aqueous corrosion of the glass. More generally all the ''source term'' models developed in France by the CEA or by ANDRA are summarized. (author). 152 refs., 33 figs

  20. Electrochemical cell and negative electrode therefor

    Science.gov (United States)

    Kaun, Thomas D.

    1982-01-01

    A secondary electrochemical cell with the positive and negative electrodes separated by a molten salt electrolyte with the negative electrode comprising a particulate mixture of lithium-aluminum alloy and electrolyte and an additive selected from graphitized carbon, Raney iron or mixtures thereof. The lithium-aluminum alloy is present in the range of from about 45 to about 80 percent by volume of the negative electrode, and the electrolyte is present in an amount not less than about 10 percent by volume of the negative electrode. The additive of graphitized carbon is present in the range of from about 1 to about 10 percent by volume of the negative electrode, and the Raney iron additive is present in the range of from about 3 to about 10 percent by volume of the negative electrode.

  1. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. The problems might include arching or ratholing in the silo/hopper. In addition, all of the blends may require consideration for their handling.

  2. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. In addition, all of the blends may require consideration for their handling. A number of engineering considerations and recommendations were prepared based on the experimental findings, experience, and other process considerations. Recommendations for future testing are included. In conjunction with future work, it is recommended that a professional consultant be engaged to guide and assist with testing and design input.

  3. BNFL Report Glass Formers Characterization

    International Nuclear Information System (INIS)

    Schumacher, R.F.

    2000-01-01

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. In addition, all of the blends may require consideration for their handling. A number of engineering considerations and recommendations were prepared based on the experimental findings, experience, and other process considerations. Recommendations for future testing are included. In conjunction with future work, it is recommended that a professional consultant be engaged to guide and assist with testing and design input

  4. BNFL Report Glass Formers Characterization

    International Nuclear Information System (INIS)

    Schumacher, R.F.

    2000-01-01

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. The problems might include arching or ratholing in the silo/hopper. In addition, all of the blends may require consideration for their handling

  5. Wear of MgO-CaO-SiO2-P2O5-F-Based Glass Ceramics Compared to Selected Dental Ceramics

    Directory of Open Access Journals (Sweden)

    Jongee Park

    2007-01-01

    Full Text Available Wear of a glass-ceramic produced through controlled crystallization of a glass in the MgO-CaO-SiO2-P2O5-F system has been evaluated and compared to various commercial dental ceramics including IPS Empress 2, Cergo Pressable Ceramic, Cerco Ceram, and Super porcelain EX-3. Wear tests were performed in accord with the ASTM G99 for wear testing with a pin-on-disk apparatus. The friction coefficient and specific wear rate of the materials investigated were determined at a load of 10 N and at ambient laboratory conditions. Microhardness of the materials was also measured to elucidate the appropriateness of these materials for dental applications.

  6. Experimental alteration of R7T7 nuclear model glass in solutions with different salinities (90/sup 0/C, 1 bar): implications for the selection of geological repositories

    Energy Technology Data Exchange (ETDEWEB)

    Godon, N.; Thomassin, J.H.; Touray, J.C.; Vernaz, E.

    1988-01-01

    In order to simulate the leaching of nuclear wastes in repositories percolated by solutions of variable salinity, leaching tests of R7T7 glass in solutions with different NaCl contents have been performed at 90/sup 0/C and 1 bar using a static procedure. A comparison of the efficiency of the different leachants indicated that the alteration was maximum in pure water and in 23.7 g (NaCl) kg/sup -1/ solution. In deionized water, uranium- and rare-earth elements simulating the actinides were found quite immobile: they have not been detected in solution but are present in the alteration layer. On the other hand, in the 23.7 g (NaCl) kg/sup -1/ solution, high amounts of uranium, cerium and neodymium have been detected in solution and did not accumulate in the solid phases. In the highest salinity brines, the bulk reactivity of the glass decreased. In all leachants, the alteration layer was structured in two parts: hydrated glass and flakes. The flakes were mainly nickel-and zinc-bearing aluminosilicate phases. When crystallized, the flakes were identified as berthierine.

  7. Direct synthesis of platelet graphitic-nanofibres as a highly porous counter-electrode in dye-sensitized solar cells.

    Science.gov (United States)

    Hsieh, Chien-Kuo; Tsai, Ming-Chi; Yen, Ming-Yu; Su, Ching-Yuan; Chen, Kuei-Fu; Ma, Chen-Chi M; Chen, Fu-Rong; Tsai, Chuen-Horng

    2012-03-28

    We synthesized platelet graphitic-nanofibres (GNFs) directly onto FTO glass and applied this forest of platelet GNFs as a highly porous structural counter-electrode in dye-sensitized solar cells (DSSCs). We investigated the electrochemical properties of counter-electrodes made from the highly porous structural GNFs and the photoconversion performance of the cells made with these electrodes.

  8. Glass frits coated with silver nanoparticles for silicon solar cells

    International Nuclear Information System (INIS)

    Li, Yingfen; Gan, Weiping; Zhou, Jian; Li, Biyuan

    2015-01-01

    Graphical abstract: - Highlights: • Silver-coated glass frits for solar cells were prepared by electroless plating. • Gum Arabic was used as the activating agent of glass frits. • Silver-coated glass frits can improve the photovoltaic performances of solar cells. - Abstract: Glass frits coated with silver nanoparticles were prepared by electroless plating. Gum Arabic (GA) was used as the activating agent of glass frits without the assistance of stannous chloride or palladium chloride. The silver-coated glass frits prepared with different GA dosages were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). The characterization results indicated that silver-coated glass frits had the structures of both glass and silver. Spherical silver nanoparticles were distributed on the glass frits evenly. The density and particle size of silver nanoparticles on the glass frits can be controlled by adjusting the GA dosage. The silver-coated glass frits were applied to silver pastes to act as both the densification promoter and silver crystallite formation aid in the silver electrodes. The prepared silver-coated glass frits can improve the photovoltaic performances of solar cells

  9. Glass frits coated with silver nanoparticles for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingfen, E-mail: lyf350857423@163.com; Gan, Weiping; Zhou, Jian; Li, Biyuan

    2015-06-30

    Graphical abstract: - Highlights: • Silver-coated glass frits for solar cells were prepared by electroless plating. • Gum Arabic was used as the activating agent of glass frits. • Silver-coated glass frits can improve the photovoltaic performances of solar cells. - Abstract: Glass frits coated with silver nanoparticles were prepared by electroless plating. Gum Arabic (GA) was used as the activating agent of glass frits without the assistance of stannous chloride or palladium chloride. The silver-coated glass frits prepared with different GA dosages were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). The characterization results indicated that silver-coated glass frits had the structures of both glass and silver. Spherical silver nanoparticles were distributed on the glass frits evenly. The density and particle size of silver nanoparticles on the glass frits can be controlled by adjusting the GA dosage. The silver-coated glass frits were applied to silver pastes to act as both the densification promoter and silver crystallite formation aid in the silver electrodes. The prepared silver-coated glass frits can improve the photovoltaic performances of solar cells.

  10. Electrodes for Semiconductor Gas Sensors

    Science.gov (United States)

    Lee, Sung Pil

    2017-01-01

    The electrodes of semiconductor gas sensors are important in characterizing sensors based on their sensitivity, selectivity, reversibility, response time, and long-term stability. The types and materials of electrodes used for semiconductor gas sensors are analyzed. In addition, the effect of interfacial zones and surface states of electrode–semiconductor interfaces on their characteristics is studied. This study describes that the gas interaction mechanism of the electrode–semiconductor interfaces should take into account the interfacial zone, surface states, image force, and tunneling effect. PMID:28346349

  11. The Thioacetate-Functionalized Self-Assembled Monolayers on Au: Toward High-Performance Ion-Selective Electrode for Ag{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jian; Zhou, Weijie; Chen, Ying; Liu, Yilong; Sun, Xiaoqiang; Xi Haitao [Changzhou Univ., Changzhou (China)

    2014-02-15

    Two classes of morpholino-substituted thioacetate have been successfully synthesized and their electrochemical properties of self-assembled monolayers (SAMs) on Au electrode are measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The barrier property of the SAMs-modified surfaces is evaluated by using potassium ferro/ferri cyanide. The results suggest that the arenethioacetate forms higher-quality close-packed blocking monolayers in comparison with alkanethioacetate. Furthermore, it has shown that the barrier properties of these monolayers can be significantly improved by mixed SAMs formation with decanethiol. From our experimental results we find that the electron transfer reaction of [Fe(CN){sub 6}]{sup 3-/4-} redox couple occurs predominantly through the pinholes and defects present in the SAM and both SAMs show a good and fast capacity in recognition for Ag{sup +}. The morphological and elementary composition have also been examined by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS)

  12. Conditioning of renewable silver amalgam film electrode for the characterization of clothianidin and its determination in selected samples by adsorptive square-wave voltammetry.

    Science.gov (United States)

    Brycht, Mariola; Skrzypek, Sławomira; Guzsvány, Valéria; Berenji, Janoš

    2013-12-15

    A new square-wave adsorptive stripping voltammetric (SWAdSV) method was developed for the determination of the neonicotinoid insecticide clothianidin (Clo), based on its reduction at a renewable silver amalgam film electrode (Hg(Ag)FE). The key point of the procedure is the pretreatment of the Hg(Ag)FE by applying the appropriate conditioning potential (-1.70 V vs. Ag/AgCl reference electrode). Under the optimized voltammetric conditions, such pretreatment resulted in the peak for the Clo reduction in Britton-Robinson buffer pH 9.0 at about -0.60 V, which was used for the analytical purpose. The developed SWAdSV procedure made it possible to determine Clo in the concentration range of 6.0×10(-7)-7.0×10(-6) mol L(-1) (LOD=1.8×10(-7) mol L(-1), LOQ=6.0×10(-7) mol L(-1)) and 7.0×10(-6)-4.0×10(-5) mol L(-1) (LOD=1.3×10(-6) mol L(-1), LOQ=4.2×10(-6) mol L(-1)). The repeatability, precision, and the recovery of the method were determined. The effect of common interfering pesticides was also investigated. Standard addition method was successfully applied and validated for the determination of Clo in spiked Warta River water, corn seeds samples, and in corn seeds samples treated with the commercial formulation PONCHO 600 FS. © 2013 Elsevier B.V. All rights reserved.

  13. A novel high electrode count spike recording array using an 81,920 pixel transimpedance amplifier-based imaging chip.

    Science.gov (United States)

    Johnson, Lee J; Cohen, Ethan; Ilg, Doug; Klein, Richard; Skeath, Perry; Scribner, Dean A

    2012-04-15

    Microelectrode recording arrays of 60-100 electrodes are commonly used to record neuronal biopotentials, and these have aided our understanding of brain function, development and pathology. However, higher density microelectrode recording arrays of larger area are needed to study neuronal function over broader brain regions such as in cerebral cortex or hippocampal slices. Here, we present a novel design of a high electrode count picocurrent imaging array (PIA), based on an 81,920 pixel Indigo ISC9809 readout integrated circuit camera chip. While originally developed for interfacing to infrared photodetector arrays, we have adapted the chip for neuron recording by bonding it to microwire glass resulting in an array with an inter-electrode pixel spacing of 30 μm. In a high density electrode array, the ability to selectively record neural regions at high speed and with good signal to noise ratio are both functionally important. A critical feature of our PIA is that each pixel contains a dedicated low noise transimpedance amplifier (∼0.32 pA rms) which allows recording high signal to noise ratio biocurrents comparable to single electrode voltage amplifier recordings. Using selective sampling of 256 pixel subarray regions, we recorded the extracellular biocurrents of rabbit retinal ganglion cell spikes at sampling rates up to 7.2 kHz. Full array local electroretinogram currents could also be recorded at frame rates up to 100 Hz. A PIA with a full complement of 4 readout circuits would span 1cm and could acquire simultaneous data from selected regions of 1024 electrodes at sampling rates up to 9.3 kHz. Published by Elsevier B.V.

  14. Preparation of poly(3,4-ethylenedioxythiophene) nanofibers modified pencil graphite electrode and investigation of over-oxidation conditions for the selective and sensitive determination of uric acid in body fluids

    Energy Technology Data Exchange (ETDEWEB)

    Özcan, Ali, E-mail: aozcan3@anadolu.edu.tr; İlkbaş, Salih

    2015-09-03

    In this study, we have performed the preparation of over-oxidized poly(3,4-ethylenedioxythiophene) nanofibers modified pencil graphite electrode (Ox-PEDOT-nf/PGE) to develop a selective and sensitive voltammetric uric acid (UA) sensor. It was noted that the over-oxidation potential and time had a prominent effect on the UA response of the Ox-PEDOT-nf/PGE. Characterizations of PEDOT-nf/PGE and Ox-PEDOT-nf/PGE have been performed by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The highest voltammetric response of UA was obtained at pH 2.0. A linear relationship between the concentration of UA and oxidation peak currents was observed in the concentration range of 0.01–20.0 μM. The detection limit (1.3 nM according to S/N = 3) and reproducibility (RSD: 4.6 % for N:10) have also been determined. The effects of different substances on the determination of UA have been investigated. A very high peak separation value of 423 mV was obtained between UA and ascorbic acid which is the major interfering substance for UA. The use of Ox-PEDOT-nf/PGE has been successfully tested in the determination of UA in human blood serum and urine samples for the first time in the literature. - Highlights: • Modification of pencil graphite with over-oxidized PEDOT nanofibers was performed. • The prepared electrodes were used in the voltammetric determination of uric acid. • The over-oxidation potential and time has a prominent effect on the responses. • A very high peak separation (463 mV) was obtained between ascorbic and uric acids. • Analytical application of the electrodes was successfully tested in real samples.

  15. Preparation of poly(3,4-ethylenedioxythiophene) nanofibers modified pencil graphite electrode and investigation of over-oxidation conditions for the selective and sensitive determination of uric acid in body fluids

    International Nuclear Information System (INIS)

    Özcan, Ali; İlkbaş, Salih

    2015-01-01

    In this study, we have performed the preparation of over-oxidized poly(3,4-ethylenedioxythiophene) nanofibers modified pencil graphite electrode (Ox-PEDOT-nf/PGE) to develop a selective and sensitive voltammetric uric acid (UA) sensor. It was noted that the over-oxidation potential and time had a prominent effect on the UA response of the Ox-PEDOT-nf/PGE. Characterizations of PEDOT-nf/PGE and Ox-PEDOT-nf/PGE have been performed by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The highest voltammetric response of UA was obtained at pH 2.0. A linear relationship between the concentration of UA and oxidation peak currents was observed in the concentration range of 0.01–20.0 μM. The detection limit (1.3 nM according to S/N = 3) and reproducibility (RSD: 4.6 % for N:10) have also been determined. The effects of different substances on the determination of UA have been investigated. A very high peak separation value of 423 mV was obtained between UA and ascorbic acid which is the major interfering substance for UA. The use of Ox-PEDOT-nf/PGE has been successfully tested in the determination of UA in human blood serum and urine samples for the first time in the literature. - Highlights: • Modification of pencil graphite with over-oxidized PEDOT nanofibers was performed. • The prepared electrodes were used in the voltammetric determination of uric acid. • The over-oxidation potential and time has a prominent effect on the responses. • A very high peak separation (463 mV) was obtained between ascorbic and uric acids. • Analytical application of the electrodes was successfully tested in real samples.

  16. High Antifouling Property of Ion-Selective Membrane: toward In Vivo Monitoring of pH Change in Live Brain of Rats with Membrane-Coated Carbon Fiber Electrodes.

    Science.gov (United States)

    Hao, Jie; Xiao, Tongfang; Wu, Fei; Yu, Ping; Mao, Lanqun

    2016-11-15

    In vivo monitoring of pH in live brain remains very essential to understanding acid-base chemistry in various physiological processes. This study demonstrates a potentiometric method for in vivo monitoring of pH in the central nervous system with carbon fiber-based proton-selective electrodes (CF-H + ISEs) with high antifouling property. The CF-H + ISEs are prepared by formation of a H + -selective membrane (H + ISM) with polyvinyl chloride polymeric matrixes containing plasticizer bis(2-ethylhexyl)sebacate, H + ionophore tridodecylamine, and ion exchanger potassium tetrakis(4-chlorophenyl)borate onto carbon fiber electrodes (CFEs). Both in vitro and in vivo studies demonstrate that the H + ISM exhibits strong antifouling property against proteins, which enables the CF-H + ISEs to well maintain the sensitivity and reversibility for pH sensing after in vivo measurements. Moreover, the CF-H + ISEs exhibit a good response to pH changes within a narrow physiological pH range from 6.0 to 8.0 in quick response time with high reversibility and selectivity against species endogenously existing in the central nervous system. The applicability of the CF-H + ISEs is illustrated by real-time monitoring of pH changes during acid-base disturbances, in which the brain acidosis is induced by CO 2 inhalation and brain alkalosis is induced by bicarbonate injections. The results demonstrate that brain pH value rapidly decreases in the amygdaloid nucleus by ca. 0.14 ± 0.01 (n = 5) when the rats breath in pure CO 2 gas, while increases in the cortex by about 0.77 ± 0.12 (n = 3) following intraperitoneal injection of 5 mmol/kg NaHCO 3 . This study demonstrates a new potentiometric method for in vivo measurement of pH change in the live brain of rats with high reliability.

  17. Fabrication of a new samarium(III) ion-selective electrode based on 3-{l_brace}[2-oxo-1(2h)-acenaphthylenyliden]amino{r_brace}-2-thioxo -1,3-thiazolidin-4-one

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Hassan Ali [Islamic Azad University, Quchan (Iran, islamic Republic of). Quchan Branch. Dept. of Chemistry]. E-mail: haszamani@yahoo.com; Ganjali, Mohammad Reza [Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of). Endocrine and Metabolism Research Center; Adib, Mehdi [University of Tehran, Tehran (Iran, Islamic Republic of). Faculty of Chemistry. Center of Excellence in Electrochemistry

    2007-07-01

    This paper introduces the development of an original PVC membrane electrode, based on 3-{l_brace}[2-oxo-1(2H)-acenaphthylenyliden]amino{r_brace}-2-thioxo-1,3-thiazolidin-4-one (ATTO) which has revealed to be a suitable carrier for Sm{sup 3+} ions. The resulting data illustrated that the electrode shows a Nernstian slope of 19.3 {+-} 0.6 mV per decade for Sm{sup 3+} ions over a broad working concentration range of 1.0 X 10{sup -6} to 1.0 X 10{sup -1} mol L{sup -1}. The lower detection limit was found to be equal to (5.5{+-} 0.3) X 10{sup -7} mol L{sup -}'1 in the pH range of 3.5-7.5, and the response time was very short ({approx}10 s). The potentiometric sensor displayed good selectivities for a number of cations such as alkali, alkaline earth, transition and heavy metal ions. (author)

  18. A new electrochemical sensor for highly sensitive and selective detection of nitrite in food samples based on sonochemical synthesized Calcium Ferrite (CaFe2O4) clusters modified screen printed carbon electrode.

    Science.gov (United States)

    Balasubramanian, Paramasivam; Settu, Ramki; Chen, Shen-Ming; Chen, Tse-Wei; Sharmila, Ganapathi

    2018-08-15

    Herein, we report a novel, disposable electrochemical sensor for the detection of nitrite ions in food samples based on the sonochemical synthesized orthorhombic CaFe 2 O 4 (CFO) clusters modified screen printed electrode. As synthesized CFO clusters were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformer infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and amperometry (i-t). Under optimal condition, the CFO modified electrode displayed a rapid current response to nitrite, a linear response range from 0.016 to 1921 µM associated with a low detection limit 6.6 nM. The suggested sensor also showed the excellent sensitivity of 3.712 μA μM -1  cm -2 . Furthermore, a good reproducibility, long-term stability and excellent selectivity were also attained on the proposed sensor. In addition, the practical applicability of the sensor was investigated via meat samples, tap water and drinking water, and showed desirable recovery rate, representing its possibilities for practical application. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Aqueous solutions/nuclear glasses interactions

    International Nuclear Information System (INIS)

    Delage, F.; Advocat, T.; Vernaz, E.; Crovisier, J.L.

    1991-01-01

    Interactions results of the borosilicate glass used in radioactive wastes confinement and aqueous solutions at various temperature and PH show that for the glass components: - the release rate evolution follows an Arrhenius law, - in acid PH, there is a selective dissolution, - in basic PH, there is a stoechiometric dissolution [fr

  20. High performance cermet electrodes

    Science.gov (United States)

    Isenberg, Arnold O.; Zymboly, Gregory E.

    1986-01-01

    Disclosed is a method of increasing the operating cell voltage of a solid oxide electrochemical cell having metal electrode particles in contact with an oxygen-transporting ceramic electrolyte. The metal electrode is heated with the cell, and oxygen is passed through the oxygen-transporting ceramic electrolyte to the surface of the metal electrode particles so that the metal electrode particles are oxidized to form a metal oxide layer between the metal electrode particles and the electrolyte. The metal oxide layer is then reduced to form porous metal between the metal electrode particles and the ceramic electrolyte.

  1. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  2. Crystallization In Multicomponent Glasses

    International Nuclear Information System (INIS)

    Kruger, A.A.; Hrma, P.R.

    2009-01-01

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  3. Printed optically transparent graphene cellulose electrodes

    Science.gov (United States)

    Sinar, Dogan; Knopf, George K.; Nikumb, Suwas; Andrushchenko, Anatoly

    2016-02-01

    Optically transparent electrodes are a key component in variety of products including bioelectronics, touch screens, flexible displays, low emissivity windows, and photovoltaic cells. Although highly conductive indium tin oxide (ITO) films are often used in these electrode applications, the raw material is very expensive and the electrodes often fracture when mechanically stressed. An alternative low-cost material for inkjet printing transparent electrodes on glass and flexible polymer substrates is described in this paper. The water based ink is created by using a hydrophilic cellulose derivative, carboxymethyl cellulose (CMC), to help suspend the naturally hydrophobic graphene (G) sheets in a solvent composed of 70% DI water and 30% 2-butoxyethanol. The CMC chain has hydrophobic and hydrophilic functional sites which allow adsorption on G sheets and, therefore, permit the graphene to be stabilized in water by electrostatic and steric forces. Once deposited on the functionalized substrate the electrical conductivity of the printed films can be "tuned" by decomposing the cellulose stabilizer using thermal reduction. The entire electrode can be thermally reduced in an oven or portions of the electrode thermally modified using a laser annealing process. The thermal process can reduce the sheet resistance of G-CMC films to < 100 Ω/sq. Experimental studies show that the optical transmittance and sheet resistance of the G-CMC conductive electrode is a dependent on the film thickness (ie. superimposed printed layers). The printed electrodes have also been doped with AuCl3 to increase electrical conductivity without significantly increasing film thickness and, thereby, maintain high optical transparency.

  4. Recycling of Glass

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Damgaard, Anders

    2011-01-01

    Glass is used for many purposes, but in the waste system glass is predominantly found in terms of beverage and food containers with a relatively short lifetime before ending up in the waste. Furthermore there is a large amount of flat glass used in building materials which also ends up in the waste...... system; this glass though has a long lifetime before ending up in the waste. Altogether these product types add up to 82% of the production of the European glass industry (IPCC, 2001). Recycling of glass in terms of cleaning and refilling of bottles as well as the use of broken glass in the production...... of new glass containers is well established in the glass industry. This chapter describes briefly howglass is produced and howwaste glass is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of glass recycling....

  5. Spectroscopic study of biologically active glasses

    Science.gov (United States)

    Szumera, M.; Wacławska, I.; Mozgawa, W.; Sitarz, M.

    2005-06-01

    It is known that the chemical activity phenomenon is characteristic for some inorganic glasses and they are able to participate in biological processes of living organisms (plants, animals and human bodies). An example here is the selective removal of silicate-phosphate glass components under the influence of biological solutions, which has been applied in designing glasses acting as ecological fertilizers of controlled release rate of the nutrients for plants. The structure of model silicate-phosphate glasses containing the different amounts of the glass network formers, i.e. Ca 2+ and Mg 2+, as a binding components were studied. These elements besides other are indispensable of the normal growth of plants. In order to establish the function and position occupied by the particular components in the glass structure, the glasses were examined by FTIR spectroscopy (with spectra decomposition) and XRD methods. It has been found that the increasing amount of MgO in the structure of silicate-phosphate glasses causes the formation of domains the structure of which changes systematically from a structure of the cristobalite type to a structure corresponding to forsterite type. Whilst the increasing content of CaO in the structure of silicate-phosphate glasses causes the formation of domains the structure of which changes from a structure typical for cristobalite through one similar to the structure of calcium orthophosphate, to a structure corresponding to calcium silicates. The changing character of domains structure is the reason of different chemical activity of glasses.

  6. Magnetic Glass Ceramics by Sintering of Borosilicate Glass and Inorganic Waste

    Directory of Open Access Journals (Sweden)

    Inès M. M. M. Ponsot

    2014-07-01

    Full Text Available Ceramics and glass ceramics based on industrial waste have been widely recognized as competitive products for building applications; however, there is a great potential for such materials with novel functionalities. In this paper, we discuss the development of magnetic sintered glass ceramics based on two iron-rich slags, coming from non-ferrous metallurgy and recycled borosilicate glass. The substantial viscous flow of the glass led to dense products for rapid treatments at relatively low temperatures (900–1000 °C, whereas glass/slag interactions resulted in the formation of magnetite crystals, providing ferrimagnetism. Such behavior could be exploited for applying the obtained glass ceramics as induction heating plates, according to preliminary tests (showing the rapid heating of selected samples, even above 200 °C. The chemical durability and safety of the obtained glass ceramics were assessed by both leaching tests and cytotoxicity tests.

  7. Electroplating of CdTe Thin Films from Cadmium Sulphate Precursor and Comparison of Layers Grown by 3-Electrode and 2-Electrode Systems

    Directory of Open Access Journals (Sweden)

    Imyhamy M. Dharmadasa

    2017-01-01

    Full Text Available Electrodeposition of CdTe thin films was carried out from the late 1970s using the cadmium sulphate precursor. The solar energy group at Sheffield Hallam University has carried out a comprehensive study of CdTe thin films electroplated using cadmium sulfate, cadmium nitrate and cadmium chloride precursors, in order to select the best electrolyte. Some of these results have been published elsewhere, and this manuscript presents the summary of the results obtained on CdTe layers grown from cadmium sulphate precursor. In addition, this research program has been exploring the ways of eliminating the reference electrode, since this is a possible source of detrimental impurities, such as K+ and Ag+ for CdS/CdTe solar cells. This paper compares the results obtained from CdTe layers grown by three-electrode (3E and two-electrode (2E systems for their material properties and performance in CdS/CdTe devices. Thin films were characterized using a wide range of analytical techniques for their structural, morphological, optical and electrical properties. These layers have also been used in device structures; glass/FTO/CdS/CdTe/Au and CdTe from both methods have produced solar cells to date with efficiencies in the region of 5%–13%. Comprehensive work carried out to date produced comparable and superior devices fabricated from materials grown using 2E system.

  8. Metal/Metal Oxide Differential Electrode pH Sensors

    Science.gov (United States)

    West, William; Buehler, Martin; Keymeulen, Didier

    2007-01-01

    Solid-state electrochemical sensors for measuring the degrees of acidity or alkalinity (in terms of pH values) of liquid solutions are being developed. These sensors are intended to supplant older electrochemical pH sensors that include glass electrode structures and reference solutions. The older sensors are fragile and subject to drift. The present developmental solid-state sensors are more rugged and are expected to be usable in harsh environments. The present sensors are based on a differential-electrode measurement principle. Each sensor includes two electrodes, made of different materials, in equilibrium with the solution of interest.

  9. A novel potentiometric biosensor for selective L-cysteine determination using L-cysteine-desulfhydrase producing Trichosporon jirovecii yeast cells coupled with sulfide electrode

    International Nuclear Information System (INIS)

    Hassan, Saad S.M.; El-Baz, Ashraf F.; Abd-Rabboh, Hisham S.M.

    2007-01-01

    Trichosporon jirovecii yeast cells are used for the first time as a source of L-cysteine desulfhydrase enzyme (EC 4.4.1.1) and incorporated in a biosensor for determining L-cysteine. The cells are grown under cadmium stress conditions to increase the expression level of the enzyme. The intact cells are immobilized on the membrane of a solid-state Ag 2 S electrode to provide a simple L-cysteine responsive biosensor. Upon immersion of the sensor in L-cysteine containing solutions, L-cysteine undergoes enzymatic hydrolysis into pyruvate, ammonia and sulfide ion. The rate of sulfide ion formation is potentiometrically measured as a function of L-cysteine concentration. Under optimized conditions (phosphate buffer pH 7, temperature 37 ± 1 deg. C and actual weight of immobilized yeast cells 100 mg), a linear relationship between L-cysteine concentration and the initial rate of sulfide liberation (dE/dt) is obtained. The sensor response covers the concentration range of 0.2-150 mg L -1 (1.7-1250 μmol L -1 ) L-cysteine. Validation of the assay method according to the quality control/quality assurance standards (precision, accuracy, between-day variability, within-day reproducibility, range of measurements and lower limit of detection) reveals remarkable performance characteristics of the proposed biosensor. The sensor is satisfactorily utilized for determination of L-cysteine in some pharmaceutical formulations. The lower limit of detection is ∼1 μmol L -1 and the accuracy and precision of the method are 97.5% and ±1.1%, respectively. Structurally similar sulfur containing compounds such as glutathione, cystine, methionine, and D-cysteine do no interfere

  10. A Simple Hydrogen Electrode

    Science.gov (United States)

    Eggen, Per-Odd

    2009-01-01

    This article describes the construction of an inexpensive, robust, and simple hydrogen electrode, as well as the use of this electrode to measure "standard" potentials. In the experiment described here the students can measure the reduction potentials of metal-metal ion pairs directly, without using a secondary reference electrode. Measurements…

  11. The Composite Insertion Electrode

    DEFF Research Database (Denmark)

    Atlung, Sven; Zachau-Christiansen, Birgit; West, Keld

    1984-01-01

    The specific energy obtainable by discharge of porous insertion electrodes is limited by electrolyte depletion in thepores. This can be overcome using a solid ion conductor as electrolyte. The term "composite" is used to distinguishthese electrodes from porous electrodes with liquid electrolyte...

  12. Near-Electrode Imager

    Energy Technology Data Exchange (ETDEWEB)

    Rathke, Jerome W.; Klingler, Robert J.; Woelk, Klaus; Gerald, Rex E.,II

    1999-05-01

    An apparatus, near-electrode imager, for employing nuclear magnetic resonance imaging to provide in situ measurements of electrochemical properties of a sample as a function of distance from a working electrode. The near-electrode imager use the radio frequency field gradient within a cylindrical toroid cavity resonator to provide high-resolution nuclear magnetic resonance spectral information on electrolyte materials.

  13. On the chemical variability of Middelburg glass beads and rods

    International Nuclear Information System (INIS)

    Karklins, K.; Kottman, J.; Hancock, R.G.V.; Sempowski, M.L.; Nohe, A.W.; Moreau, J.-F.; Aufreiter, S.; Kenyon, I.

    2001-01-01

    Forty-three glass samples from a late 16th-early 17th century, glass beadmaking house in Middelburg, the Netherlands, were selected for maximum colouring variability, including plain and multi-coloured varieties. The glass chemistries were quite diverse, within each colour grouping. For each single colour of glass, anticipated colouring elements (copper for turquoise blue, cobalt for dark blue, manganese for rose, and tin for white) were used, with the exception of two beads that were opacified wih antimony rather than with tin. Multi-coloured glass glasses (chevron beads) produced chemistries that match the mixing of the different coloured glasses. In some cases, low relative amounts of some inter-mixed glasses were not detectable against the composition of the major glass component. (author). 16 refs., 3 tabs

  14. DWPF Glass Melter Technology Manual: Volume 1

    International Nuclear Information System (INIS)

    Iverson, D.C.

    1993-01-01

    This document details information about the design of a glass melter to be used at the Defense Waste Processing Facility located at the Savannah River Site. Topics include: melter overview, design basis, materials, vessel configuration, insulation, refractory configuration, electrical isolation, electrodes, riser and pour spout heater design, dome heaters, feed tubes, drain valves, differential pressure pouring, and melter test results. Information is conveyed using many diagrams and photographs

  15. Effects of solar radiation on glass

    Science.gov (United States)

    Tucker, Dennis S.; Kinser, Donald L.

    1991-01-01

    The effects of solar radiation of selected glasses are reported. Optical property degradation is studied using UV-Vis spectrophotometry. Strength changes are measured using a concentric ring bend test. Direct fracture toughness measurements using an indentation test are planned.

  16. Dielectric elastomers with novel highly-conducting electrodes

    Science.gov (United States)

    Böse, Holger; Uhl, Detlev

    2013-04-01

    Beside the characteristics of the elastomer material itself, the performance of dielectric elastomers in actuator, sensor as well as generator applications depends also on the properties of the electrode material. Various electrode materials based on metallic particles dispersed in a silicone matrix were manufactured and investigated. Anisotropic particles such as silver-coated copper flakes and silver-coated glass flakes were used for the preparation of the electrodes. The concentration of the metallic particles and the thickness of the electrode layers were varied. Specific conductivities derived from resistance measurements reached about 100 S/cm and surmount those of the reference materials based on graphite and carbon black by up to three orders of magnitude. The high conductivities of the new electrode materials can be maintained even at very large stretch deformations up to 200 %.

  17. Graphene-based transparent electrodes for hybrid solar cells

    Directory of Open Access Journals (Sweden)

    Pengfei eLi

    2014-11-01

    Full Text Available The graphene-based transparent and conductive films were demonstrated to be cost-effective electrodes working in organic-inorganic hybrid Schottky solar cells. Large area graphene films were produced by chemical vapor deposition (CVD on copper foils and transferred onto glass as transparent electrodes. The hybrid solar cell devices consist of solution processed poly (3, 4-ethlenedioxythiophene: poly (styrenesulfonate (PEDOT: PSS which is sandwiched between silicon wafer and graphene electrode. The solar cells based on graphene electrodes, especially those doped with HNO3, has comparable performance to the reference devices using commercial indium tin oxide (ITO. Our work suggests that graphene-based transparent electrode is a promising candidate to replace ITO.

  18. A model for electrode effects using percolation theory

    International Nuclear Information System (INIS)

    Wuethrich, R.; Bleuler, H.

    2004-01-01

    Electrode effects are known for more than 150 years. These effects, with undesirable consequences in industrial aluminium electrolysis, can be used to micro-machine glass with Spark Assisted Chemical Engraving (SACE). In this paper, a novel approach for theoretical analysis of the phenomenon is proposed by considering the bubble growth and bubble departure from electrodes as a stochastic process. The critical conditions (critical voltage and current density) are predicted in function of electrode geometry and electrolyte concentration as well as the static mean current-voltage characteristics prior to the onset of the effects. The different regions of the current-voltage characteristics, as identified by previous authors, are described and explained. It is shown that all relevant processes for the onset of the electrodes effects happen in the adherence region of the bubble layer. The model is applied for vertical cylindrical electrodes and compared with experimental data

  19. Spin glasses

    International Nuclear Information System (INIS)

    Mookerjee, Abhijit

    1976-01-01

    ''Spin glasses'', are entire class of magnetic alloys of moderate dilution, in which the magnetic atoms are far enough apart to be unlike the pure metal, but close enough so that the indirect exchange energy between them (mediated by the s-d interaction between local moments and conduction electrons) dominates all other energies. Characteristic critical phenomena displayed such as freezing of spin orientation at 'Tsub(c)' and spreading of magnetic ordering, are pointed out. Anomalous behaviour, associated with these critical phenomena, as reflected in : (i) Moessbauer spectroscopy giving hyperfine splitting at Tsub(c), (ii) maxima in susceptibility and remanent magnetism, (iii) thermopower maxima and change in slope, (iv) Characteristic cusp in susceptibility and its removal by very small magnetic fields, and (v) conductivity-resistivity measurements, are discussed. Theoretical developments aimed at explaining these phenomena, in particular, the ideas from percolation and localisation theories, and the approach based on the gellations of polymers, are discussed. Finally, a new approach based on renormalisation group in disordered systems is also briefly mentioned. (K.B.)

  20. Physical Property Investigation of Contemporary Glass lonomer and Resin Modified Glass lonomer Restorative Materials

    Science.gov (United States)

    2016-05-24

    selected physical properties of nine contemporary and recently-marketed glass-ionomer cement (GIC) and four resin-modified glass-ionomer cement {RMGIC...stainless steel molds. Testing was completed on a universal testing machine unt il failure. Knoop Hardness was obtained using fai led fracture toughness...address caries, function, biocompatibility, and minimal environmental impact. 2·3 Glass-ionomer cements were invented and developed by Wilson and Kent

  1. Growth of TiO2-ZrO2 Binary Oxide Electrode for Dye Sensitized Solar Cell Application

    International Nuclear Information System (INIS)

    Than Than Win; Aye Myint Myat Kywe; Shwe Yee Win; Honey Thaw; Yin Maung Maung; Ko Ko Kyaw Soe

    2011-12-01

    TiO2-ZrO2 fine binary oxide was prepared by mechanochemical milling process to be homogeneous binary oxide powder. TiO2-ZrO2 paste was deposited on microscopic glass slide by rolling. It was immersed in the henna solution and annealed at 100C for 2h. It was deposited onto another glass slide and used as counter electrode (second electrode). Two glass slides were offset and two binder clips were used to hold the electrodes together. Photovoltaic properties of TiO2-ZrO2 cell were measured and it was expected to utilize the dye sensitized solar cells application.

  2. Cyanex based uranyl sensitive polymeric membrane electrodes.

    Science.gov (United States)

    Badr, Ibrahim H A; Zidan, W I; Akl, Z F

    2014-01-01

    Novel uranyl selective polymeric membrane electrodes were prepared using three different low-cost and commercially available Cyanex extractants namely, bis(2,4,4-trimethylpentyl) phosphinic acid [L1], bis(2,4,4-trimethylpentyl) monothiophosphinic acid [L2] and bis(2,4,4-trimethylpentyl) dithiophosphinic acid [L3]. Optimization and performance characteristics of the developed Cyanex based polymer membrane electrodes were determined. The influence of membrane composition (e.g., amount and type of ionic sites, as well as type of plasticizer) on potentiometric responses of the prepared membrane electrodes was studied. Optimized Cyanex-based membrane electrodes exhibited Nernstian responses for UO₂(2+) ion over wide concentration ranges with fast response times. The optimized membrane electrodes based on L1, L2 and L3 exhibited Nernstian responses towards uranyl ion with slopes of 29.4, 28.0 and 29.3 mV decade(-1), respectively. The optimized membrane electrodes based on L1-L3 showed detection limits of 8.3 × 10(-5), 3.0 × 10(-5) and 3.3 × 10(-6) mol L(-1), respectively. The selectivity studies showed that the optimized membrane electrodes exhibited high selectivity towards UO₂(2+) ion over large number of other cations. Membrane electrodes based on L3 exhibited superior potentiometric response characteristics compared to those based on L1 and L2 (e.g., widest linear range and lowest detection limit). The analytical utility of uranyl membrane electrodes formulated with Cyanex extractant L3 was demonstrated by the analysis of uranyl ion in different real samples for nuclear safeguards verification purposes. The results obtained using direct potentiometry and flow-injection methods were compared with those measured using the standard UV-visible and inductively coupled plasma spectroscopic methods. © 2013 Published by Elsevier B.V.

  3. ELECTROCHEMICAL DECHLORINATION OF TRICHLOROETHYLENE USING GRANULAR-GRAPHITE ELECTRODES

    Science.gov (United States)

    Electrochemical dechlorination of TCE was conducted in a glass column using granular graphite as electrodes. A constant voltage of 15 volt was applied resulting in 60-62 mA of current. Approximately 4-6% of the TCE was dechlorinated. Among the reduced TCE, more than 95% was compl...

  4. Effect of annealing over optoelectronic properties of graphene based transparent electrodes

    Science.gov (United States)

    Yadav, Shriniwas; Kaur, Inderpreet

    2016-04-01

    Graphene, an atom-thick two dimensional graphitic material have led various fundamental breakthroughs in the field of science and technology. Due to their exceptional optical, physical and electrical properties, graphene based transparent electrodes have shown several applications in organic light emitting diodes, solar cells and thin film transistors. Here, we are presenting effect of annealing over optoelectronic properties of graphene based transparent electrodes. Graphene based transparent electrodes have been prepared by wet chemical approach over glass substrates. After fabrication, these electrodes tested for optical transmittance in visible region. Sheet resistance was measured using four probe method. Effect of thermal annealing at 200 °C was studied over optical and electrical performance of these electrodes. Optoelectronic performance was judged from ratio of direct current conductivity to optical conductivity (σdc/σopt) as a figure of merit for transparent conductors. The fabricated electrodes display good optical and electrical properties. Such electrodes can be alternatives for doped metal oxide based transparent electrodes.

  5. Nickel hydrogen bipolar battery electrode design

    Science.gov (United States)

    Puglisi, V. J.; Russell, P.; Verrier, D.; Hall, A.

    1985-01-01

    The preferred approach of the NASA development effort in nickel hydrogen battery design utilizes a bipolar plate stacking arrangement to obtain the required voltage-capacity configuration. In a bipolar stack, component designs must take into account not only the typical design considerations such as voltage, capacity and gas management, but also conductivity to the bipolar (i.e., intercell) plate. The nickel and hydrogen electrode development specifically relevant to bipolar cell operation is discussed. Nickel oxide electrodes, having variable type grids and in thicknesses up to .085 inch are being fabricated and characterized to provide a data base. A selection will be made based upon a system level tradeoff. Negative (hydrpogen) electrodes are being screened to select a high performance electrode which can function as a bipolar electrode. Present nickel hydrogen negative electrodes are not capable of conducting current through their cross-section. An electrode was tested which exhibits low charge and discharge polarization voltages and at the same time is conductive. Test data is presented.

  6. Engineering Silver Nanowire Networks: From Transparent Electrodes to Resistive Switching Devices.

    Science.gov (United States)

    Du, Haiwei; Wan, Tao; Qu, Bo; Cao, Fuyang; Lin, Qianru; Chen, Nan; Lin, Xi; Chu, Dewei

    2017-06-21

    Metal nanowires (NWs) networks with high conductance have shown potential applications in modern electronic components, especially the transparent electrodes over the past decade. In metal NW networks, the electrical connectivity of nanoscale NW junction can be modulated for various applications. In this work, silver nanowire (Ag NW) networks were selected to achieve the desired functions. The Ag NWs were first synthesized by a classic polyol process, and spin-coated on glass to fabricate transparent electrodes. The as-fabricated electrode showed a sheet resistance of 7.158 Ω □ -1 with an optical transmittance of 79.19% at 550 nm, indicating a comparable figure of merit (FOM, or Φ TC ) (13.55 × 10 -3 Ω -1 ). Then, two different post-treatments were designed to tune the Ag NWs for not only transparent electrode but also for threshold resistive switching (RS) application. On the one hand, the Ag NW film was mechanically pressed to significantly improve the conductance by reducing the junction resistance. On the other hand, an Ag@AgO x core-shell structure was deliberately designed by partial oxidation of Ag NWs through simple ultraviolet (UV)-ozone treatment. The Ag core can act as metallic interconnect and the insulating AgO x shell acts as a switching medium to provide a conductive pathway for Ag filament migration. By fabricating Ag/Ag@AgO x /Ag planar structure, a volatile threshold switching characteristic was observed and an on/off ratio of ∼100 was achieved. This work showed that through different post-treatments, Ag NW network can be engineered for diverse functions, transforming from transparent electrodes to RS devices.

  7. Glass compositions suitable for PFR wastes

    International Nuclear Information System (INIS)

    Boult, K.A.; Dalton, J.T.; Eccles, E.W.; Hough, A.; Marples, J.A.C.; Paige, E.L.; Sutcliffe, P.W.

    1988-03-01

    Previous work had identified glass compositions that were suitable for vitrifying current and future high level wastes from the Prototype Fast Reactor (PFR) fuel reprocessing plant. Further work on these glasses has shown that: a) Foaming and crystallisation can occur under certain conditions, both probably associated with the presence of iron in the waste. Either of these could lead to greater difficulties in processing. b) Inconel 690, the preferred JCM (Joule-heated Ceramic Melter) electrode material has an acceptable corrosion rate at 1200 0 C: ca 0.6mm.y -1 . c) The leach rates are unaffected by radiation damage. The density of the glass decreases slightly with α-dose, with a dependency that extrapolates, at infinite time, to an 0.13% linear expansion. d) The concentrations of the radiologically important elements Tc, Np, Pu and Am, observed in a 'repository simulation' leach test, were satisfactorily low. (author)

  8. Boron Isotope Compositions of Selected Fresh MORB Glasses From the Northern EPR (8-10° N): Implications for MORB Magma Contamination

    Science.gov (United States)

    Le Roux, P. J.; Shirey, S. B.; Hauri, E. H.; Perfit, M. R.

    2003-12-01

    The petrogenetic role of seawater and seawater-equilibrated altered crust in the magmatic evolution of basalts formed at mid-ocean ridges is not well-constrained. Observed excess Cl in oceanic basaltic magmas led to established models of assimilation of a saline brine component, although the physical form of this component and whether any other components contaminate MORB magmas remain unresolved. Light stable isotopes such as B are valuable in further refining our understanding of these magmatic processes. The light element B has two stable isotopes (mass 11 and 10) and B isotopic ratio ranges significantly in oceanic settings: e.g. depleted upper mantle (δ 11B -10‰ ), fresh MORB magmas (δ 11B -1.2 to -6.5‰ ), altered oceanic crust (δ 11B +2 to +9‰ ), hydrothermal fluids (δ 11B +30 to +36.5‰ ), and seawater (δ 11B +38.5‰ ). We have developed an in situ laser ablation, multiple multiplier ICP-MS at DTM (see le Roux et al., in press) that has reliable uncertainties for B isotope analyses better than 1‰ (2σ ) over concentration ranges from 0.3 ppm to above 30 ppm. This technique makes nearly any size glass sample amenable to B isotope study. B isotopic compositions were obtained on 16 fresh MORB magmas from the northern East Pacific Rise (EPR) from 8 to 10° N. This region of the EPR has an extensive, existing MORB glass collection, with well-constrained general geochemistry and petrology, recovered from sites on-axis, off-axis (including young off-axis eruptions; abyssal hills), and the Siquerios fracture zone. Geophysical data from this region imaged the top of the dike section (layer 2A) and the sub-axial magma chambers (AMC). Data for these MORB glasses indicate the variable addition of H2O, Cl, F, Li and B to these magmas prior to eruption. The excess Cl can be accounted for by variable (Kent et al, 1999). Variable magma degassing places the contamination of some of these magmas at depths within the oceanic crust close to the top of the AMC

  9. A novel high-performance counter electrode for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Wang Guiqiang; Lin Ruifeng; Lin Yuan; Li Xueping; Zhou Xiaowen; Xiao Xurui

    2005-01-01

    A novel Pt counter electrode for dye-sensitized solar cells (DSC) was prepared by thermal decomposition of H 2 PtCl 6 on NiP-plated glass substrate. The charge-transfer kinetic properties of the platinized NiP-plated glass electrode (Pt/NiP electrode) for triiodide reduction were studied by electrochemical impedance spectroscopy. Pt/NiP electrode has the advantage over the platinized FTO conducting glass electrode (Pt/FTO electrode) in increasing the light reflectance and reducing the sheet resistance leading to improve the light harvest efficiency and the fill factor of the dye-sensitized solar cells effectively. The photon-to-current efficiency and the overall conversion efficiency of DSC using Pt/NiP counter electrode is increased by 20% and 33%, respectively, compared to that of using Pt/FTO counter electrode. Examination of the anodic dissolution and the long-term test on the variation of charge-transfer resistance indicates the good stability of the Pt/NiP electrode in the electrolyte containing iodide/triiodide

  10. Ammonium ions determination with polypyrrole modified electrode

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Dall´Antonia

    2007-03-01

    Full Text Available The present work relates the preparation of polypyrrole films (PPy deposited on surfaces of glass carbon, nickel and ITO (tin oxide doped with indium on PET plastic, in order to study the ammonium detection. The popypyrrole films were polymerized with dodecylbenzenesulfonate (DBSA on the electrodes, at + 0,70 V vs. Ag/AgCl, based on a solution containing the pyrrole monomer and the amphiphilic salt. Films deposited on glass carbon presented better performance. Cyclic voltammetries, between – 1,50 to + 0,5 V vs. Ag/AgCl, were repeated adding different concentrations of NH4Cl, in order to observe the behavior of the film as a possible detector of ions NH4+. The peak current for oxidation varies with the concentration of ammonium. A linear region can be observed in the band of 0 to 80 mM, with a sensibility (Sppy approximately similar to 4,2 mA mM-1 cm-2, showing the efficacy of the electrodes as sensors of ammonium ions. The amount of deposited polymer, controlled by the time of growth, does not influence on the sensor sensibility. The modified electrode was used to determine ammonium in grounded waters.

  11. lead glass brick

    CERN Multimedia

    When you look through the glass at a picture behind, the picture appears raised up because light is slowed down in the dense glass. It is this density (4.06 gcm-3) that makes lead glass attractive to physicists. The refractive index of the glass is 1.708 at 400nm (violet light), meaning that light travels in the glass at about 58% its normal speed. At CERN, the OPAL detector uses some 12000 blocks of glass like this to measure particle energies.

  12. Uncharged positive electrode composition

    Science.gov (United States)

    Kaun, Thomas D.; Vissers, Donald R.; Shimotake, Hiroshi

    1977-03-08

    An uncharged positive-electrode composition contains particulate lithium sulfide, another alkali metal or alkaline earth metal compound other than sulfide, e.g., lithium carbide, and a transition metal powder. The composition along with a binder, such as electrolytic salt or a thermosetting resin is applied onto an electrically conductive substrate to form a plaque. The plaque is assembled as a positive electrode within an electrochemical cell opposite to a negative electrode containing a material such as aluminum or silicon for alloying with lithium. During charging, lithium alloy is formed within the negative electrode and transition metal sulfide such as iron sulfide is produced within the positive electrode. Excess negative electrode capacity over that from the transition metal sulfide is provided due to the electrochemical reaction of the other than sulfide alkali metal or alkaline earth metal compound.

  13. Selective dissolution of halide perovskites as a step towards recycling solar cells.

    Science.gov (United States)

    Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

    2016-05-23

    Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb(2+) cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

  14. Selective dissolution of halide perovskites as a step towards recycling solar cells

    Science.gov (United States)

    Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

    2016-05-01

    Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

  15. A New Platform for Profiling Degradation-Related Impurities Via Exploiting the Opportunities Offered by Ion-Selective Electrodes: Determination of Both Diatrizoate Sodium and Its Cytotoxic Degradation Product.

    Science.gov (United States)

    Riad, Safaa M; Abd El-Rahman, Mohamed K; Fawaz, Esraa M; Shehata, Mostafa A

    2018-05-01

    Although the ultimate goal of administering active pharmaceutical ingredients (APIs) is to save countless lives, the presence of impurities and/or degradation products in APIs or formulations may cause harmful physiological effects. Today, impurity profiling (i.e., the identity as well as the quantity of impurity in a pharmaceutical) is receiving critical attention from regulatory authorities. Despite the predominant use of spectroscopic and chromatographic methods over electrochemical methods for impurity profiling of APIs, this work investigates the opportunities offered by electroanalytical methods, particularly, ion-selective electrodes (ISEs), for profiling degradation-related impurities (DRIs) compared with conventional spectroscopic and chromatographic methods. For a meaningful comparison, diatrizoate sodium (DTA) was chosen as the anionic X-ray contrast agent based on its susceptibility to deacetylation into its cytotoxic and mutagenic degradation product, 3,5-diamino-2,4,6 triiodobenzoic acid (DTB). This cationic diamino compound can be also detected as an impurity in the final product because it is used as a synthetic precursor for the synthesis of DTA. In this study, four novel sensitive and selective sensors for the determination of both DTA and its cytotoxic degradation products are presented. Sensors I and II were developed for the determination of the anionic drug, DTA, and sensors III and IV were developed for the determination of the cationic cytotoxic impurity. The use of these novel sensors not only provides a stability-indicating method for the selective determination of DTA in the presence of its degradation product, but also permits DRI profiling. Moreover, a great advantage of these proposed ISE systems is their higher sensitivity for the quantification of DTB relative to other spectroscopic and chromatographic methods, so it can measure trace amounts of DTB impurities in DTA bulk powder and pharmaceutical formulation without a need for

  16. Nuclear waste glass melter design including the power and control systems

    International Nuclear Information System (INIS)

    Chapman, C.C.

    1982-01-01

    An energy balance of a joule-heated nuclear waste glass melter is used to discuss the problems in the design of the melter geometry and in the specifications of the power and control systems. The relationships between geometry, electrode current density, production rate, load voltage, and load power are presented graphically. The influence of liquid feeding on the surface of the glass and the variability of nuclear waste glass on the design and control during operation is discussed. 10 refs

  17. PLUTONIUM SOLUBILITY IN HIGH-LEVEL WASTE ALKALI BOROSILICATE GLASS

    Energy Technology Data Exchange (ETDEWEB)

    Marra, J.; Crawford, C.; Fox, K.; Bibler, N.

    2011-01-04

    The solubility of plutonium in a Sludge Batch 6 (SB6) reference glass and the effect of incorporation of Pu in the glass on specific glass properties were evaluated. A Pu loading of 1 wt % in glass was studied. Prior to actual plutonium glass testing, surrogate testing (using Hf as a surrogate for Pu) was conducted to evaluate the homogeneity of significant quantities of Hf (Pu) in the glass, determine the most appropriate methods to evaluate homogeneity for Pu glass testing, and to evaluate the impact of Hf loading in the glass on select glass properties. Surrogate testing was conducted using Hf to represent between 0 and 1 wt % Pu in glass on an equivalent molar basis. A Pu loading of 1 wt % in glass translated to {approx}18 kg Pu per Defense Waste Processing Facility (DWPF) canister, or about 10X the current allowed limit per the Waste Acceptance Product Specifications (2500 g/m{sup 3} of glass or about 1700 g/canister) and about 30X the current allowable concentration based on the fissile material concentration limit referenced in the Yucca Mountain Project License Application (897 g/m{sup 3}3 of glass or about 600 g Pu/canister). Based on historical process throughput data, this level was considered to represent a reasonable upper bound for Pu loading based on the ability to provide Pu containing feed to the DWPF. The task elements included evaluating the distribution of Pu in the glass (e.g. homogeneity), evaluating crystallization within the glass, evaluating select glass properties (with surrogates), and evaluating durability using the Product Consistency Test -- Method A (PCT-A). The behavior of Pu in the melter was evaluated using paper studies and corresponding analyses of DWPF melter pour samples.The results of the testing indicated that at 1 wt % Pu in the glass, the Pu was homogeneously distributed and did not result in any formation of plutonium-containing crystalline phases as long as the glass was prepared under 'well-mixed' conditions

  18. Plutonium Solubility In High-Level Waste Alkali Borosilicate Glass

    International Nuclear Information System (INIS)

    Marra, J.; Crawford, C.; Fox, K.; Bibler, N.

    2011-01-01

    The solubility of plutonium in a Sludge Batch 6 (SB6) reference glass and the effect of incorporation of Pu in the glass on specific glass properties were evaluated. A Pu loading of 1 wt % in glass was studied. Prior to actual plutonium glass testing, surrogate testing (using Hf as a surrogate for Pu) was conducted to evaluate the homogeneity of significant quantities of Hf (Pu) in the glass, determine the most appropriate methods to evaluate homogeneity for Pu glass testing, and to evaluate the impact of Hf loading in the glass on select glass properties. Surrogate testing was conducted using Hf to represent between 0 and 1 wt % Pu in glass on an equivalent molar basis. A Pu loading of 1 wt % in glass translated to ∼18 kg Pu per Defense Waste Processing Facility (DWPF) canister, or about 10X the current allowed limit per the Waste Acceptance Product Specifications (2500 g/m 3 of glass or about 1700 g/canister) and about 30X the current allowable concentration based on the fissile material concentration limit referenced in the Yucca Mountain Project License Application (897 g/m 3 3 of glass or about 600 g Pu/canister). Based on historical process throughput data, this level was considered to represent a reasonable upper bound for Pu loading based on the ability to provide Pu containing feed to the DWPF. The task elements included evaluating the distribution of Pu in the glass (e.g. homogeneity), evaluating crystallization within the glass, evaluating select glass properties (with surrogates), and evaluating durability using the Product Consistency Test -- Method A (PCT-A). The behavior of Pu in the melter was evaluated using paper studies and corresponding analyses of DWPF melter pour samples.The results of the testing indicated that at 1 wt % Pu in the glass, the Pu was homogeneously distributed and did not result in any formation of plutonium-containing crystalline phases as long as the glass was prepared under 'well-mixed' conditions. The incorporation of 1 wt

  19. ELECTROD FLUOR-SELECTIV

    Directory of Open Access Journals (Sweden)

    Mariana DÎRU

    2018-03-01

    Full Text Available A fost preparat un senzor anionic specific, bazat pe pivalatul trinuclear al cromului(III ca material electro­activ încorporat în membrana PVC plastifiată. Senzorul prezintă răspuns Nernstian (55,78 mV/decadă în intervalul de concentrație 10-1-10-4 mol/L cu limita de detecție 2,0∙10-5 mol/L pentru anionul fluorură. Domeniul optim de pH de funcţionare a electrodului asamblat este ˃5. Senzorul dat are un timp de răspuns de 30-60 s și reproductibilitatea rezultatelor se menține timp de 3 luni. Coeficienții potențiometrici ai selectivității au fost determinați prin metoda soluțiilor separate. A fost realizată aplicarea acestor electrozi la analiza pastei de dinți ce conține fluorură și rezultatele experimentale au fost comparate cu datele de pe prospect.FLUORIDE-SELECTIVE ELECTRODEA specific anionic sensor has been prepared, based on trinuclearchromium(III pivalate as sensing material incorpo­rated into the plasticized PVC-membrane. The sensor exhibited Nernstian response (55,78 mV/decade in the region between 10-1-10-4 mol/L with a detection limit of 2,0∙10-5 mol/L for fluoride. The working pH of the electrode was in the 5-6 range. The sensor has a response time 30-60 s and can be used for least 3 month. The potentiometric selectivity coefficients were determined by separate solution method. Application of these electrodes to the analysis of toothpaste containing fluoride has been realized and experimental results have been compared with the data on the prospectus.

  20. Glass and nuclear wastes

    International Nuclear Information System (INIS)

    Sombret, C.

    1982-10-01

    Glass shows interesting technical and economical properties for long term storage of solidified radioactive wastes by vitrification or embedding. Glass composition, vitrification processes, stability under irradiation, thermal stability and aqueous corrosion are studied [fr

  1. Microstructuring of glasses

    CERN Document Server

    Hülsenberg, Dagmar; Bismarck, Alexander

    2008-01-01

    As microstructured glass becomes increasingly important for microsystems technology, the main application fields include micro-fluidic systems, micro-analysis systems, sensors, micro-actuators and implants. And, because glass has quite distinct properties from silicon, PMMA and metals, applications exist where only glass devices meet the requirements. The main advantages of glass derive from its amorphous nature, the precondition for its - theoretically - direction-independent geometric structurability. Microstructuring of Glasses deals with the amorphous state, various glass compositions and their properties, the interactions between glasses and the electromagnetic waves used to modify it. Also treated in detail are methods for influencing the geometrical microstructure of glasses by mechanical, chemical, thermal, optical, and electrical treatment, and the methods and equipment required to produce actual microdevices.

  2. Measurement of optical glasses

    International Nuclear Information System (INIS)

    Nicolau-Rebigan, S.

    1978-11-01

    The possibilities of measurement of the optical glasses parameters needed in building optical devices especially in lasers devices are presented. In the first chapter the general features of the main optical glasses as well as the modalities of obtaining them are given. Chapter two defines the optical glass parameters, and the third chapter describes the measuring methods of the optical glass parameters. Finally, the conclusions which point out the utilization of this paper are presented. (author)

  3. FY-97 operations of the pilot-scale glass melter to vitrify simulated ICPP high activity sodium-bearing waste

    International Nuclear Information System (INIS)

    Musick, C.A.

    1997-11-01

    A 3.5 liter refractory-lined joule-heated glass melter was built to test the applicability of electric melting to vitrify simulated high activity waste (HAW). The HAW streams result from dissolution and separation of Idaho Chemical Processing Plant (ICPP) calcines and/or radioactive liquid waste. Pilot scale melter operations will establish selection criteria needed to evaluate the application of joule heating to immobilize ICPP high activity waste streams. The melter was fabricated with K-3 refractory walls and Inconel 690 electrodes. It is designed to be continuously operated at 1,150 C with a maximum glass output rate of 10 lbs/hr. The first set of tests were completed using surrogate HAW-sodium bearing waste (SBW). The melter operated for 57 hours and was shut down due to excessive melt temperatures resulting in low glass viscosity (< 30 Poise). Due to the high melt temperature and low viscosity the molten glass breached the melt chamber. The melter has been dismantled and examined to identify required process improvement areas and successes of the first melter run. The melter has been redesigned and is currently being fabricated for the second run, which is scheduled to begin in December 1997

  4. Trace level and highly selective determination of urea in various real samples based upon voltammetric analysis of diacetylmonoxime-urea reaction product on the carbon nanotube/carbon paste electrode.

    Science.gov (United States)

    Alizadeh, Taher; Ganjali, Mohammad Reza; Rafiei, Faride

    2017-06-29

    In this study an innovative method was introduced for selective and precise determination of urea in various real samples including urine, blood serum, soil and water. The method was based on the square wave voltammetry determination of an electroactive product, generated during diacetylmonoxime reaction with urea. A carbon paste electrode, modified with multi-walled carbon nanotubes (MWCNTs) was found to be an appropriate electrochemical transducer for recording of the electrochemical signal. It was found that the chemical reaction conditions influenced the analytical signal directly. The calibration graph of the method was linear in the range of 1 × 10 -7 - 1 × 10 -2  mol L -1 . The detection limit was calculated to be 52 nmol L -1 . Relative standard error of the method was also calculated to be 3.9% (n = 3). The developed determination procedure was applied for urea determination in various real samples including soil, urine, plasma and water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Smooth Nanowire/Polymer Composite Transparent Electrodes

    KAUST Repository

    Gaynor, Whitney; Burkhard, George F.; McGehee, Michael D.; Peumans, Peter

    2011-01-01

    Smooth composite transparent electrodes are fabricated via lamination of silver nanowires into the polymer poly-(4,3-ethylene dioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS). The surface roughness is dramatically reduced compared to bare nanowires. High-efficiency P3HT:PCBM organic photovoltaic cells can be fabricated using these composites, reproducing the performance of cells on indium tin oxide (ITO) on glass and improving the performance of cells on ITO on plastic. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Smooth Nanowire/Polymer Composite Transparent Electrodes

    KAUST Repository

    Gaynor, Whitney

    2011-04-29

    Smooth composite transparent electrodes are fabricated via lamination of silver nanowires into the polymer poly-(4,3-ethylene dioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS). The surface roughness is dramatically reduced compared to bare nanowires. High-efficiency P3HT:PCBM organic photovoltaic cells can be fabricated using these composites, reproducing the performance of cells on indium tin oxide (ITO) on glass and improving the performance of cells on ITO on plastic. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...

  8. Toward a consistent model for glass dissolution

    International Nuclear Information System (INIS)

    Strachan, D.M.; McGrail, B.P.; Bourcier, W.L.

    1994-01-01

    Understanding the process of glass dissolution in aqueous media has advanced significantly over the last 10 years through the efforts of many scientists around the world. Mathematical models describing the glass dissolution process have also advanced from simple empirical functions to structured models based on fundamental principles of physics, chemistry, and thermodynamics. Although borosilicate glass has been selected as the waste form for disposal of high-level wastes in at least 5 countries, there is no international consensus on the fundamental methodology for modeling glass dissolution that could be used in assessing the long term performance of waste glasses in a geologic repository setting. Each repository program is developing their own model and supporting experimental data. In this paper, we critically evaluate a selected set of these structured models and show that a consistent methodology for modeling glass dissolution processes is available. We also propose a strategy for a future coordinated effort to obtain the model input parameters that are needed for long-term performance assessments of glass in a geologic repository. (author) 4 figs., tabs., 75 refs

  9. Low-cost optical fabrication of flexible copper electrode via laser-induced reductive sintering and adhesive transfer

    Science.gov (United States)

    Back, Seunghyun; Kang, Bongchul

    2018-02-01

    Fabricating copper electrodes on heat-sensitive polymer films in air is highly challenging owing to the need of expensive copper nanoparticles, rapid oxidation of precursor during sintering, and limitation of sintering temperature to prevent the thermal damage of the polymer film. A laser-induced hybrid process of reductive sintering and adhesive transfer is demonstrated to cost-effectively fabricate copper electrode on a polyethylene film with a thermal resistance below 100 °C. A laser-induced reductive sintering process directly fabricates a high-conductive copper electrode onto a glass donor from copper oxide nanoparticle solution via photo-thermochemical reduction and agglomeration of copper oxide nanoparticles. The sintered copper patterns were transferred in parallel to a heat-sensitive polyethylene film through self-selective surface adhesion of the film, which was generated by the selective laser absorption of the copper pattern. The method reported here could become one of the most important manufacturing technologies for fabricating low-cost wearable and disposable electronics.

  10. Electrode stabilizing materials

    Science.gov (United States)

    Amine, Khalil; Abouimrane, Ali; Moore, Jeffrey S.; Odom, Susan A.

    2015-11-03

    An electrolyte includes a polar aprotic solvent; an alkali metal salt; and an electrode stabilizing compound that is a monomer, which when polymerized forms an electrically conductive polymer. The electrode stabilizing compound is a thiophene, a imidazole, a anilines, a benzene, a azulene, a carbazole, or a thiol. Electrochemical devices may incorporate such electrolytes.

  11. Durable fuel electrode

    DEFF Research Database (Denmark)

    2017-01-01

    the composite. The invention also relates to the use of the composite as a fuel electrode, solid oxide fuel cell, and/or solid oxide electrolyser. The invention discloses a composite for an electrode, comprising a three-dimensional network of dispersed metal particles, stabilised zirconia particles and pores...

  12. Assessment of water/glass interactions in waste glass melter operation

    International Nuclear Information System (INIS)

    Postma, A.K.; Chapman, C.C.; Buelt, J.L.

    1980-04-01

    A study was made to assess the possibility of a vapor explosion in a liquid-fed glass melter and during off-standard conditions for other vitrification processes. The glass melter considered is one designed for the vitrification of high-level nuclear wastes and is comprised of a ceramic-lined cavity with electrodes for joule heating and processing equipment required to add feed and withdraw glass. Vapor explosions needed to be considered because experience in other industrial processes has shown that violent interactions can occur if a hot liquid is mixed with a cooler, vaporizable liquid. Available experimental evidence and theoretical analyses indicate that destructive glass/water interactions are low probability events, if they are possible at all. Under standard conditions, aspects of liquid-fed melter operation which work against explosive interactions include: (1) the aqueous feed is near its boiling point; (2) the feed contains high concentrations of suspended particles; (3) molten glass has high viscosity (greater than 20 poise); and (4) the glass solidifies before film boiling can collapse. While it was concluded that vapor explosions are not expected in a liquid-fed melter, available information does not allow them to be ruled out altogether. Several precautionary measures which are easily incorporated into melter operation procedures were identified and additional experiments were recommended

  13. The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    Jokić Anja B.

    2013-01-01

    Full Text Available The application of the hydrogen-palladium electrode (H2/Pd as the indicator electrode for the determination of relative acidity scale (Es, mV of tetrahydrofuran (THF and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH, which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051

  14. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

    Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

  15. Multiple Glass Ceilings

    OpenAIRE

    Russo, Giovanni; Hassink, Wolter

    2011-01-01

    Both vertical (between job levels) and horizontal (within job levels) mobility can be sources of wage growth. We find that the glass ceiling operates at both margins. The unexplained part of the wage gap grows across job levels (glass ceiling at the vertical margin) and across the deciles of the intra-job-level wage distribution (glass ceiling at the horizontal margin). This implies that women face many glass ceilings, one for each job level above the second, and that the glass ceiling is a p...

  16. Homogeneity of Inorganic Glasses

    DEFF Research Database (Denmark)

    Jensen, Martin; Zhang, L.; Keding, Ralf

    2011-01-01

    Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity...... of different glass products can be quantified and ranked. This approach is based on determination of both the optical intensity and dimension of the striations in glasses. These two characteristic values areobtained using the image processing method established recently. The logarithmic ratio between...

  17. Platinum and palladium alloys suitable as fuel cell electrodes

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention concerns electrode catalysts used in fuel cells, such as proton exchange membrane (PEM) fuel cells. The invention is related to the reduction of the noble metal content and the improvement of the catalytic efficiency by low level substitution of the noble metal to provide new...... and innovative catalyst compositions in fuel cell electrodes. The novel electrode catalysts of the invention comprise a noble metal selected from Pt and Pd alloyed with an alkaline earth metal....

  18. Platinum and palladium alloys suitable as fuel cell electrodes

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention concerns electrode catalysts used in fuel cells, such as proton exchange membrane (PEM) fuel cells. The invention is related to the reduction of the noble metal content and the improvement of the catalytic5 efficiency by low level substitution of the noble metal to provide new...... and innovative catalyst compositions in fuel cell electrodes. The novel electrode catalysts of the invention comprise a noble metal selected from Pt and Pd alloyed with a lanthanide metal....

  19. Amodiaquine polymeric membrane electrode.

    Science.gov (United States)

    Malongo, T Kimbeni; Blankert, B; Kambu, O; Amighi, K; Nsangu, J; Kauffmann, J-M

    2006-04-11

    The construction and electrochemical response characteristics of two types of poly(vinyl chloride) (PVC) membrane sensors for the determination of amodiaquine hydrochloride (ADQ.2HCl) are described. The sensing membrane comprised an ion-pair formed between the cationic drug and sodium tetraphenyl borate (NaTPB) or potassium tetrakis(4-chlorophenyl) borate (KTCPB) in a plasticized PVC matrix. Eight PVC membrane ion-selective electrodes were fabricated and studied. Several plasticizers were studied namely, dioctyl phthalate (DOP), 2-nitrophenyl octyl ether (NPOE), dioctyl phenylphosphonate (DOPP) and bis(2-ethylhexyl)adipate (EHA). The sensors display a fast, stable and near-Nernstian response over a relative wide ADQ concentration range (3.2 x 10(-6) to 2.0 x 10(-2) M), with slopes comprised between 28.5 and 31.4 mV dec(-1) in a pH range comprised between pH 3.7 and 5.5. The assay of amodiaquine hydrochloride in pharmaceutical dosage forms using one of the proposed sensors gave average recoveries of 104.3 and 99.9 with R.S.D. of 0.3 and 0.6% for tablets (Malaritab) and a reconstituted powder containing ADQ.2HCl, respectively. The sensor was also used for dissolution profile studies of two drug formulations. The sensor proved to have a good selectivity for ADQ.2HCl over some inorganic and organic compounds, however, berberine chloride interfered significantly. The results were validated by comparison with a spectrophotometric assay according to the USP pharmacopoeia.

  20. Modiolus-Hugging Intracochlear Electrode Array with Shape Memory Alloy

    Directory of Open Access Journals (Sweden)

    Kyou Sik Min

    2013-01-01

    Full Text Available In the cochlear implant system, the distance between spiral ganglia and the electrodes within the volume of the scala tympani cavity significantly affects the efficiency of the electrical stimulation in terms of the threshold current level and spatial selectivity. Because the spiral ganglia are situated inside the modiolus, the central axis of the cochlea, it is desirable that the electrode array hugs the modiolus to minimize the distance between the electrodes and the ganglia. In the present study, we propose a shape-memory-alloy-(SMA- embedded intracochlear electrode which gives a straight electrode a curved modiolus-hugging shape using the restoration force of the SMA as triggered by resistive heating after insertion into the cochlea. An eight-channel ball-type electrode array is fabricated with an embedded titanium-nickel SMA backbone wire. It is demonstrated that the electrode array changes its shape in a transparent plastic human cochlear model. To verify the safe insertion of the electrode array into the human cochlea, the contact pressures during insertion at the electrode tip and the contact pressures over the electrode length after insertion were calculated using a 3D finite element analysis. The results indicate that the SMA-embedded electrode is functionally and mechanically feasible for clinical applications.