WorldWideScience

Sample records for catalytic adsorptive stripping

  1. Trace vanadium analysis by catalytic adsorptive stripping voltammetry using mercury-coated micro-wire and polystyrene-coated bismuth film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Dansby-Sparks, Royce; Chambers, James Q. [Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600 (United States); Xue Ziling, E-mail: xue@ion.chem.utk.edu [Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600 (United States)

    2009-06-08

    An electrochemical technique has been developed for ultra-trace (ng L{sup -1}) vanadium (V) measurement. Catalytic adsorptive stripping voltammetry for V analysis was developed at mercury-coated gold micro-wire electrodes (MWEs, 100 {mu}m) in the presence of gallic acid (GA) and bromate ion. A potential of -0.275 V (vs Ag/AgCl) was used to accumulate the complex in acetate buffer (pH 5.0) at the electrode surface followed by a differential pulse voltammetric scan. Parameters affecting the electrochemical response, including pH, concentration of GA and bromate, deposition potential and time have been optimized. Linear response was obtained in the 0-1000 ng L{sup -1} range (2 min deposition), with a detection limit of 0.88 ng L{sup -1}. The method was validated by comparison of results for an unknown solution of V by atomic absorption measurement. The protocol was evaluated in a real sample by measuring the amount of V in river water samples. Thick bismuth film electrodes with protective polystyrene films have also been made and evaluated as a mercury free alternative. However, ng L{sup -1} level detection was only attainable with extended (10 min) deposition times. The proposed use of MWEs for the detection of V is sensitive enough for future use to test V concentration in biological fluids treated by the advanced oxidation process (AOP).

  2. Tritium stripping by a catalytic exchange stripper

    International Nuclear Information System (INIS)

    Heung, L.K.; Gibson, G.W.; Ortman, M.S.

    1991-01-01

    A catalytic exchange process for stripping elemental tritium from gas streams has been demonstrated. The process uses a catalyzed isotopic exchange reaction between tritium in the gas phase and protium or deuterium in the solid phase on alumina. The reaction is catalyzed by platinum deposited on the alumina. The process has been tested with both tritium and deuterium. Decontamination factors (ration of inlet and outlet tritium concentrations) as high as 1000 have been achieved, depending on inlet concentration. The test results and some demonstrated applications are presented

  3. Optimising carbon electrode materials for adsorptive stripping voltammetry

    OpenAIRE

    Chaisiwamongkhol, K; Batchelor-McAuley, C; Sokolov, S; Holter, J; Young, N; Compton, R

    2017-01-01

    Different types of carbon electrode materials for adsorptive stripping voltammetry are studied through the use of cyclic voltammetry. Capsaicin is utilised as a model compound for adsorptive stripping voltammetry using unmodified and modified basal plane pyrolytic graphite (BPPG) electrodes modified with multi-walled carbon nanotubes, carbon black or graphene nanoplatelets, screen printed carbon electrodes (SPE), carbon nanotube modified screen printed electrodes, and carbon paste electrodes....

  4. Adsorptive stripping voltammetry in lipophilic vitamins determination

    Directory of Open Access Journals (Sweden)

    Milan Sýs

    2016-06-01

    Full Text Available The aim of this contribution was to check if adsorptive stripping differential pulse voltammetry (AdSDPV is suitable tool for sensitive simultenous electrochemical detection of lipophilic vitamins. Retinol (vitamin A1, cholecalciferol (vitamin D3, α-tocopherol (vitamin E and phylloquinone (vitamin K1 were selected as representatives. All electrochemical measurements were performed in two separate steps due to the lipophilic character of the analytes. In the first step, an accumulation of lipophilic vitamin on the surface of glassy carbon electrode (GCE was done by immersing working electrode into the aqueous‑acetonitrile solutions (50%, v/v of each vitamin (50.0 µmol.L-1 at 400 rpm for 5 min. In the second one, differential pulse voltammetry of accumulated vitamins was performed in 0.01 mol.L-1 acetate (pH 4.5 buffer at potential step (Estep 5 mV, potential of amplitude (Eampl 25 mV, interval time (t 0.1 s and scan rate (ν 50 mV.s-1. It was observed that electrochemical behaviour of lipophilic vitamins adsorbed on surface of solid GCE in the aqueous electrolyte was very similar to those performed in organic/aqueous electrolyte in literature. Due to reversible electrochemical behaviour of vitamin K1 (phylloquinone/phyllohydroquinone redox couple, it was possible to detect all lipophilic vitamins only in one analysis. Observed values of peak potentials (Ep were sufficiently different for their recognition which was confirmed by the analysis of real sample. The results obtained in this study showed that simultaneous determination of some lipophilic vitamins is possible requiring further optimization study. For this reason, it is necessary to understand this work as an initial step in simultaneous determination of lipophilic vitamins without application of any chromatographic technique.

  5. Adsorptive stripping voltammetric methods for determination of aripiprazole

    Directory of Open Access Journals (Sweden)

    Derya Aşangil

    2012-06-01

    Full Text Available Anodic behavior of aripiprazole (ARP was studied using electrochemical methods. Charge transfer, diffusion and surface coverage coefficients of adsorbed molecules and the number of electrons transferred in electrode mechanisms were calculated for quasi-reversible and adsorption-controlled electrochemical oxidation of ARP at 1.15 V versus Ag/AgCl at pH 4.0 in Britton–Robinson buffer (BR on glassy carbon electrode. Voltammetric methods for direct determination of ARP in pharmaceutical dosage forms and biological samples were developed. Linearity range is found as from 11.4 μM (5.11 mg/L to 157 μM (70.41 mg/L without stripping mode and it is found as from 0.221 μM (0.10 mg/L to 13.6 μM (6.10 mg/L with stripping mode. Limit of detection (LOD was found to be 0.11 μM (0.05 mg/L in stripping voltammetry. Methods were successfully applied to assay the drug in tablets, human serum and human urine with good recoveries between 95.0% and 104.6% with relative standard deviation less than 10%. Keywords: Adsorptive stripping voltammetry, Aripiprazole, Electrochemical behavior, Human serum and urine, Pharmaceuticals

  6. SQUARE WAVE CATHODIC STRIPPING VOLTAMMETRY ADSORPTIVE FOR NICKEL AND COBALT ANALYSIS

    Directory of Open Access Journals (Sweden)

    Saryati Saryati

    2010-06-01

    Full Text Available The adsorptive stripping voltammetric determination of Ni and Co based on adsorption of the Ni/Co and dimethylglioxime (DMG complex on a hanging mercury drop electrode is studied. The reduction current of the adsorbed DMG complex is measured by square wave cathodic stripping voltammetry method. The effect of various parameters such as ligand concentration, pH of supporting electrolytic, adsorption potential and adsorption time on the current peak of Ni and Co voltammogram were studied. Optimum condition of this method are supporting electrolyte pH 9, DMG concentration 5×10 -4 M, adsorption potential -0.7 V vs Ag/AgCl and adsorption time 180 second. A linier relationship between the current peak and Ni or Co concentration was obtained in the range 5 - 30 ng/mL and the detection limit 0.6 ng/ml for both Ni and Co. The recovery of Ni and Co were 98.11-104.17% using standard biological materials with RSD 2.59 - 10.37%. Based on ";t"; test can be conclude that the result are nearly equal to the standard reference material.   Keywords: adsorptive stripping voltammetric, dimethylglioxime complex, nickel, cobalt

  7. Adsorptive stripping voltammetric determination of trace amounts of lead in environmental water samples with complicated matrix

    Directory of Open Access Journals (Sweden)

    Grabarczyk M.

    2013-04-01

    Full Text Available A sensitive, simple and fast adsorptive stripping voltammetric procedure for trace determination of lead in environmental water samples has been developed. The method is based on adsorptive accumulation of the Pb(II-cupferron complex onto a hanging mercury drop electrode, followed by the reduction of the adsorbed species by a voltammetric scan using differential pulse modulation. The interference from surface active substances was eliminated by adsorption of interferents onto an Amberlite XAD-16 resin. Optimumconditions for removing the surfactants by mixing the analysed sample with resin were evaluated. The accuracy of the method was tested by analyzing certified reference material (SPS-WW1 Waste Water.

  8. Adsorptive stripping chronopotentiometry (AdSCP). Part 1: Fundamental features

    NARCIS (Netherlands)

    Leeuwen, van H.P.; Town, R.M.

    2007-01-01

    Direct heterogeneous electron transfer reactions and the molecular orientation of d-fructose dehydrogenase (FDH, from Gluconobacter sp.) adsorbed onto electrodes were investigated. Catalytic oxidation currents based on the direct electron transfer reactions of FDH adsorbed onto basal-plane, highly

  9. Adsorptive stripping voltammetric determination of uranium with cephradine

    International Nuclear Information System (INIS)

    Ali, A.M.M.; Ghandour, M.A.; Khodari, M.

    1995-01-01

    Uranium adsorbed with cephradine is reduced on a hanging mercury drop electrode. This property was exploited in developing a highly sensitive stripping voltammetric procedure for the determination of uranium. A detection limit 2 x 10 -9 mol I -1 (0.5 μg I -1 ) of uranium ion is obtained with an 180 s accumulation time. Cyclic voltammetry was used to characterize the interfacial and redox behaviour. The effects of various parameters are discussed. Experimental conditions include the use of 5 x 10 -6 mol I -1 cephradine in 0.05 mol I -1 sodium perchlorate (pH ''approx ='' 6.5), an accumulation potential of 0.0 V versus SCE and a direct current stripping technique. The response is linear up to 5 x 10 -6 mol I -1 uranium and the relative standard deviation at 1 x 10 -7 mol I -1 ) UO 2+ is 4.4%. The effect of other metal ions was investigated. (author)

  10. Adsorptive stripping voltammetric determination of triprolidine hydrochloride in pharmaceutical tablets.

    Science.gov (United States)

    Zayed, S I M; Habib, I H I

    2005-01-01

    The electrochemical behavior of antihistaminic drug, viz. triprolidine hydrochloride (TripCl), at a hanging mercury drop electrode (HMDE) is investigated. Chemical and electrical parameters affecting the adsorptive voltammetric measurements are optimized. Different modes of sweep, viz. direct current DC, normal pulse NP, differential pulse DP and square wave SW modes, over the potential range from -800 to -1400 mV, are used in the presence of 0.04 M Britton-Robinson buffer pH 11, with accumulation time 30 s, scan rate 50 mV/s and pulse amplitude 50 mV. The reduction process is irreversible and involved the transfer of two electrons and two protons. Their responses are linear over the concentration range 15-157 ng/ml with average correlation coefficient 0.9998, while the detection limit is 2.64, 6.24, 8.80 and 2.12 ng/ml for DC, DP, SW and NP mode, respectively. The differential pulse method has been applied successfully for the determination of the drug in Egyptian pharmaceutical preparation with mean recovery 99.55+/-0.67%.

  11. Very Low Rate Constants of Bimolecular CO Adsorption on Anionic Gold Clusters: Implications for Catalytic Activity

    Czech Academy of Sciences Publication Activity Database

    Balteanu, I.; Balaj, O. P.; Fox, B. S.; Beyer, M. K.; Bastl, Zdeněk; Bondybey, V. E.

    2003-01-01

    Roč. 5, - (2003), s. 1213-1218 ISSN 1463-9076 Institutional research plan: CEZ:AV0Z4040901 Keywords : bimolecular * adsorption * catalytic activity Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.959, year: 2003

  12. Estimation of uranium in different types of water and sand samples by adsorptive stripping voltammetry

    International Nuclear Information System (INIS)

    Bhalke, Sunil; Raghunath, Radha; Mishra, Suchismita; Suseela, B.; Tripathi, R.M.; Pandit, G.G.; Shukla, V.K.; Puranik, V.D.

    2005-01-01

    A method is standardized for the estimation of uranium by adsorptive stripping voltammetry using chloranilic acid (CAA) as complexing agent. The optimum parameters to get best sensitivity and good reproducibility for uranium were 60s adsorption time, pH 1.8, chloranilic acid (2x10 -4 M) and 0.002M EDTA. The peak potential under this condition was found to be -0.03 V. With these optimum parameters a sensitivity of 1.19 nA/nM uranium was observed. Detection limit for this optimum parameter was found to be 0.55 nM. This can be further improved by increasing adsorption time. Using this method, uranium was estimated in different type of water samples such as seawater, synthetic seawater, stream water, tap water, well water, bore well water and process water. This method has also been used for estimation of uranium in sand, organic solvent used for extraction of uranium from phosphoric acid and its raffinate. Sample digestion procedures used for estimation of uranium in various matrices are discussed. It has been observed from the analysis that the uranium peak potentials changes with matrix of the sample, hence, standard addition method is the best method to get reliable and accurate results. Quality assurance of the standardized method is verified by analyzing certified reference water sample from USDOE, participating intercomparison exercises and also by estimating uranium content in water samples both by differential pulse adsorptive stripping voltammetric and laser fluorimetric techniques. (author)

  13. Cathodic adsorptive stripping voltammetric determination of Ribavirin in pharmaceutical dosage form, urine and serum

    Directory of Open Access Journals (Sweden)

    Ahmed A. Abdel Gaber

    2017-05-01

    Full Text Available A sensitive, simple and rapid square-wave adsorptive stripping voltammetric method was developed and validated for the determination of Ribavirin in pharmaceutical formulations. The proposed method was based on the electrochemical reduction of Ribavirin at a hanging mercury drop electrode in Britton Robinson buffer at pH 10. A well-defined peak was observed at 880 mV with 30 s of accumulation time and 50 mV of accumulation potential. Under these optimized conditions, the square-wave adsorptive stripping voltammetric peak current showed a linear correlation on drug concentration over the range of 1 × 10−10–2 × 10−7 mol L−1 with a correlation coefficient of 0.9995 for the proposed method. The detection and quantitation limits for this method were 2.02 × 10−10 and 6.80 × 10−10 mol L−1, respectively. The results obtained for intra-day and inter-day precision (as RSD % were between 0.447% and 1.024%. This method was applied successfully for the determination of Ribavirin in its pharmaceutical dosage forms with mean recoveries of 99.68 ± 0.13 with RSD % of 0.81% and 99.20 ± 0.24 with RSD % of 0.49% for two concentrations 5 × 10−9 and 5 × 10−8 mol L−1, respectively for 200 mg capsules. The results obtained from the developed square-wave adsorptive stripping voltammetric method were compared with those obtained by the analytical method reported in the literature.

  14. Adsorptive Cathodic Stripping Voltammetric Determination of Cefoperazone in Bulk Powder, Pharmaceutical Dosage Forms, and Human Urine

    Directory of Open Access Journals (Sweden)

    Vu Dang Hoang

    2013-01-01

    Full Text Available The electroreduction behaviour and determination of cefoperazone using a hanging mercury drop electrode were investigated. Cyclic voltammograms of cefoperazone recorded in universal Britton-Robinson buffers pH 3–6 exhibited a single irreversible cathodic peak. The process was adsorption-controlled. Britton-Robinson buffer 0.04 M pH 4.0 was selected as a supporting electrolyte for quantitative purposes by differential pulse and square wave adsorptive cathodic stripping voltammetry. The experimental voltammetric conditions were optimized using Central Composite Face design. A reduction wave was seen in the range from −0.7 to −0.8 V. These voltammetric techniques were successfully validated as per ICH guidelines and applied for the determination of cefoperazone in its single and sulbactam containing powders for injection and statistically comparable to USP-HPLC. They were further extended to determine cefoperazone in spiked human urine with no matrix effect.

  15. Trace determination of yttrium and some heavy rare-earths by adsorptive stripping voltammetry

    International Nuclear Information System (INIS)

    Wang, J.; Zadeii, J.M.

    1986-01-01

    The interfacial and redox behaviour of rare-earth chelates the Solochrome Violet RS are exploited for developing a sensitive adsorptive stripping procedure. Yttrium and heavy rare earths such as dysprosium, holmium and ytterbium can thus be measured at ng/ml levels and below, by controlled adsorptive accumulation of the metal chelate at the hanging mercury drop electrode, followed by voltammetric measurement of the surface species. With a 3-min preconcentration time, the detection limit ranges from 5 x 10 -10 to 1.4 x 10 -9 M. The relative standard deviation at the 7 ng/ml level ranges from 4 to 7%. A separation method is required to differentiate between the individual rare-earth metals. (author)

  16. Theoretical and experimental study of redox processes combined with adsorption phenomena under conditions of square-wave voltammetry

    OpenAIRE

    Gulaboski, Rubin

    2001-01-01

    Theoretical models of four electrode reactions coupled with adsorption phenomena under conditions of square-wave voltammetry are developed: simple surface redox reaction, surface catalytic reaction, cathodic stripping reaction of I order, and cathodic stripping reaction of II order.

  17. Determination of copper in whole blood by differential pulse adsorptive stripping voltammetry

    Directory of Open Access Journals (Sweden)

    Tarik Attar

    2014-02-01

    Full Text Available A selective and sensitive method for determination of copper in blood by adsorptive differential pulse cathodic stripping voltammetry is presented. The method is based on adsorptive accumulation of the complexes of Cu (II ions with benzenesulfonyl hydrazide onto hanging mercury drop electrode (HMDE, followed by the reduction of the adsorbed species by differential pulse cathodic stripping voltammetry. The effect of various parameters such as supporting electrolyte, concentration of benzenesulfonyl hydrazide, accumulation potential, accumulation time and stirring rate on the selectivity and sensitivity were studied. The optimum conditions for determination of copper include perchloric acid 0.03 M, concentration of benzenesulfonyl hydrazide 7.5×10-5 M, the accumulation potential of -350 mV (vs. Ag/AgCl, the accumulation time of 50 s, and the scan rate of 50 mV s-1. Under optimized conditions, linear calibration curves were established for the concentration of Cu (II in the range of 0.62-275 ng mL-1, with detection limit of 0.186 ng mL-1 for Cu (II. The procedure was successfully applied to the determination of copper ion in whole blood samples.

  18. Direct determination of molybdenum in seawater by adsorption cathodic stripping square-wave voltammetry.

    Science.gov (United States)

    Sun, Y C; Mierzwa, J; Lan, C R

    2000-06-30

    A reliable and very sensitive procedure for the determination of trace levels of molybdenum in seawater is proposed. The complex of molybdenum with 8-hydroxyquinoline (Oxine) is analyzed by cathodic stripping square-wave voltammetry based on the adsorption collection onto a hanging mercury drop electrode (HMDE). This procedure of molybdenum determination was found to be more favorable than differential pulse cathodic stripping voltammetry because of inherently faster scan rate and much better linearity obtained through the one-peak (instead of one-of-two peaks) calibration. The variation of polarographic peak and peak current with a pH, adsorption time, adsorption potential, and some instrumental parameters such as scan rate and pulse height were optimized. The alteration of polarographic wave and its likely mechanism are also discussed. The relationship between peak current and molybdenum concentration is linear up to 150 mug l(-1). Under the optimal analytical conditions, the determination limit of 0.5 mug l(-1) Mo was reached after 60 s of the stirred collection. The estimated detection limit is better than 0.1 mug l(-1) of Mo. The applicability of this method to analysis of seawater was assessed by the determination of molybdenum in two certified reference seawater samples (CASS-2 and NASS-2) and the comparison of the analytical results for real seawater samples (study on a vertical distribution of Mo in the seawater column) with the results obtained by Zeeman-corrected electrothermal atomization atomic absorption spectrometry (Zeeman ETAAS). A good agreement between two used methods of molybdenum determination was obtained.

  19. Adsorption and catalytic properties of skeleton nickel alloyed by tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Erzhanova, M S; Sokol' skii, D V; Popov, N I; Kondratenko, V I

    1977-02-01

    Adsorption properties are studied of Ni-Ta-catalysts composed of 20-50% Ni, 0-30% Ta, 50% Al with respect to hydrogen; their activity in a number of reactions has been tested. The adsorption capacity is characterized with respect to H/sub 2/ by the methods of thermodesorption and conductometry. It is shown that three forms to hydrogen (..beta.., ..gamma.., sigma) adsorb onto the surface of the alloyed catalysts, whose desorption peaks overlap because of their high mobility and interchangeability. Variation of activity, selectivity and isomerizing capacity of the catalysts correlates with the content of a weakly adsorbed mobile form of H/sub 2/.

  20. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Quesada-Penate, I. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Julcour-Lebigue, C., E-mail: carine.julcour@ensiacet.fr [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Jauregui-Haza, U. J. [Instituto Superior de Tecnologias y Ciencias Aplicadas, Ave. Salvador Allende y Luaces, Habana (Cuba); Wilhelm, A. M.; Delmas, H. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer Three activated carbons (AC) compared as adsorbents and oxidation catalysts. Black-Right-Pointing-Pointer Similar evolution for catalytic and adsorptive properties of AC over reuses. Black-Right-Pointing-Pointer Acidic and mesoporous AC to be preferred, despite lower initial efficiency. Black-Right-Pointing-Pointer Oxidative degradation of paracetamol improves biodegradability. Black-Right-Pointing-Pointer Convenient hybrid adsorption-regenerative oxidation process for continuous treatment. - Abstract: The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  1. Electrochemistry and analytical determination of lysergic acid diethylamide (LSD) via adsorptive stripping voltammetry.

    Science.gov (United States)

    Merli, Daniele; Zamboni, Daniele; Protti, Stefano; Pesavento, Maria; Profumo, Antonella

    2014-12-01

    Lysergic acid diethylamide (LSD) is hardly detectable and quantifiable in biological samples because of its low active dose. Although several analytical tests are available, routine analysis of this drug is rarely performed. In this article, we report a simple and accurate method for the determination of LSD, based on adsorptive stripping voltammetry in DMF/tetrabutylammonium perchlorate, with a linear range of 1-90 ng L(-1) for deposition times of 50s. LOD of 1.4 ng L(-1) and LOQ of 4.3 ng L(-1) were found. The method can be also applied to biological samples after a simple extraction with 1-chlorobutane. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Tritium removal from air streams by catalytic oxidation and water adsorption

    International Nuclear Information System (INIS)

    Sherwood, A.E.

    1976-06-01

    An effective method of capturing tritium from air streams is by catalytic oxidation followed by water adsorption on a microporous solid adsorbent. Performance of a burner/dryer combination is illustrated by overall mass balance equations. Engineering design methods for packed bed reactors and adsorbers are reviewed, emphasizing the experimental data needed for design and the effect of operating conditions on system performance

  3. Speciation of Co(II) and Ni(II) in anaerobic bioreactors measured by competitive ligand exchange - adsorptive stripping voltammetry

    NARCIS (Netherlands)

    Jansen, S.; Steffen, F.; Threels, W.F.; Leeuwen, van H.P.

    2005-01-01

    Competitive ligand exchange-adsorptive stripping voltammetry is applied to speciation analysis of dissolved Ni(II) and Co(II) in an anaerobic bioreactor and similar batch media. Co and Ni speciation in these media can be measured down to concentration levels of ca. 1 nM. Sulfide interference is

  4. Adsorptive stripping voltammetric behaviour of copper complexes of some heterocyclic azo compounds.

    Science.gov (United States)

    Farias, P A; Ferreira, S L; Ohara, A K; Bastos, M B; Goulart, M S

    1992-10-01

    Controlled adsorptive accumulation of copper complexed with TAN, TAC, TAR and TAM (heterocyclic azo-compounds) on a static mercury drop electrode provides the basis for the direct stripping measurement of this element in the nanomolar concentration level. The ligand TAN exhibited great sensitivity and better separation of the peak current of the ligand in relation to the complex. The reduction current of adsorbed complex ions of copper is measured by linear scan cathodic stripping voltammetry, preceded by a period of accumulation of a few minutes. The peak potential is at approximately -0.37 V vs. Ag/AgCl. Optimal experimental parameters were found to be a TAN concentration of 1 x 10(-5)M, an accumulation potential of -0.22 V, and a solution pH of 3.7 (acetate buffer). The detection limit is 0.8nM after a 5-min accumulation with a stirred solution, and the response is linear up to 50 mug/l. Many common cations and anions do not interfere in the determination of copper. The interference of titanium is eliminated by addition of fluoride ion. Results are reported for a fresh water sample.

  5. Adsorptive Stripping Determination of Trace Nickel Using Bismuth Modified Mesoporous Carbon Composite Electrode

    Science.gov (United States)

    Ouyang, Ruizhuo; Feng, Kai; Su, Yongfu; Zong, Tianyu; Zhou, Xia; Lei, Tian; Jia, Pengpeng; Cao, Penghui; Zhao, Yuefeng; Guo, Ning; Chang, Haizhou; Miao, Yuqing; Zhou, Shuang

    Novel bismuth nanoparticle-modified mesoporous carbon (MPC) was successfully prepared on a glassy carbon electrode (Bi@MPC/GCE) for the adsorptive stripping voltammetric determination of nickel by complexing with dimethylglyoxime (DMG). The presence of MPC obviously improved the properties of Bi particles like the electron transfer ability, particle size and hydrophicility, important parameters to achieve preferable analytical performances of Bi@MPC/GCE toward Ni(II). The best electrochemical behaviors of Bi@MPC/GCE was obtained for the stripping determination of Ni(II), compared with electrodes individually modified with Bi and MPC. The synergic effect between metallic Bi and ordered MPC (forming a 3D array like Bi microelectrodes) made major contribution to such improved electrochemical properties of Bi@MPC/GCE for Ni(II) sensing. The good linear analytical curve was achieved in a Ni(II) concentration range from 0.1μM to 5.0μM with a correlation coefficient of 0.9995. The detection limit and sensitivity were calculated to be 1.2nM (S/N=3) and 1410μAmM-1cm-2, respectively. The new method was successfully applied to Ni(II) determination in soybean samples with recoveries higher than 99% and proved to be a simple, efficient alternative for Ni(II) monitoring in real samples.

  6. Determination of Sudan I in drinks containing Sunset yellow by adsorptive stripping voltammetry.

    Science.gov (United States)

    Gómez, Marisol; Arancibia, Verónica; Aliaga, Margarita; Núñez, Claudia; Rojas-Romo, Carlos

    2016-12-01

    An efficient, fast and sensitive method for the determination of Sudan I (SI) in drinks containing Sunset yellow (Sy) is developed and validated using an adsorptive stripping voltammetric procedure. Sy is currently added to a large number of foods; however during their synthesis SI may be produced. The determination is based on adsorption of Sy and SI onto HMDE and later reduction of the azo group at -0.71 and -0.82V, respectively. Using the best set of the experimental conditions (pH 12.3; Eads: -0.40V) for the determination of SI in Sy, a linear response for SI in the concentration range 0.5-27.2μgL(-1) was found, with a detection limit of 1.5μgL(-1) in a tads of only 30s. The method was applied to the determination of SI in commercial drinks with satisfactory results. The presence of SI was confirmed by mass spectrometry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorptionCatalytic wet air oxidation on activated carbons

    International Nuclear Information System (INIS)

    Quesada-Peñate, I.; Julcour-Lebigue, C.; Jáuregui-Haza, U.J.; Wilhelm, A.M.; Delmas, H.

    2012-01-01

    Highlights: ► Three activated carbons (AC) compared as adsorbents and oxidation catalysts. ► Similar evolution for catalytic and adsorptive properties of AC over reuses. ► Acidic and mesoporous AC to be preferred, despite lower initial efficiency. ► Oxidative degradation of paracetamol improves biodegradability. ► Convenient hybrid adsorption–regenerative oxidation process for continuous treatment. - Abstract: The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  8. Improving catalytic selectivity through control of adsorption orientation

    Science.gov (United States)

    Pang, Simon H.

    In this thesis, we present an investigation, starting from surface science experiments, leading to design of supported catalysts, of how adsorption orientation can be used to affect reaction selectivity of highly functional molecules. The surface chemistry of furfuryl alcohol and benzyl alcohol and their respective aldehydes was studied on a Pd(111) single-crystal surface under ultra-high vacuum conditions. Temperature-programmed desorption experiments showed that synergistic chemistry existed between the aromatic ring and the oxygen-containing functional group, each allowing the other to participate in reaction pathways that a monofunctional molecule could not. Most important of these was a deoxygenation reaction that occurred more readily when the surface was crowded by the highest exposures. High-resolution electron energy loss spectroscopy revealed that at these high exposures, molecules were oriented upright on the surface, with the aromatic function extending into vacuum. In contrast, at low exposures, molecules were oriented flat on the surface. The upright adsorption geometry was correlated with deoxygenation, whereas the flat-lying geometry was correlated with decarbonylation. The insight gained from surface science experiments was utilized in catalyst design. Self-assembled monolayers of alkanethiolates were used to systematically reduce the average surface ensemble size, and the reaction selectivity was tracked. When a sparsely-packed monolayer was used, such as one formed by 1-adamantanethiol, the reactant furfural was still able to lie flat on the surface and the reaction selectivity was similar to that of the uncoated catalyst. However, when a densely-packed monolayer, formed by 1-octadecanethiol, was used, furfural was not able to adsorb flat on the surface and instead adopted an upright conformation, leading to a drastic increase in aldehyde hydrogenation and hydrodeoxygenation reaction selectivity. Using an even higher sulfur coverage from a

  9. Simultaneous determination of copper, lead and cadmium by cathodic adsorptive stripping voltammetry using artificial neural network

    International Nuclear Information System (INIS)

    Ensafi, Ali A.; Khayamian, T.; Benvidi, A.; Mirmomtaz, E.

    2006-01-01

    In this work, simultaneous determination of two groups of elements consisting of Pb(II)-Cd(II) and Cu(II)-Pb(II)-Cd(II) using adsorptive cathodic stripping voltammetry are described. The method is based on accumulation of these metal ions on mercury electrode using xylenol orange as a suitable complexing agent. The potential was scanned to the negative direction and the differential pulse stripping voltammograms were recorded. The instrumental and chemical factors were optimized using artificial neural network. The optimized conditions were obtained in pH of 5.5, xylenol orange concentration of 4.0 μM, accumulation potential of -0.50 V, accumulation time of 30 s, scan rate of 10 mV/s and pulse height of 70 mV. The relationship between the peak current versus concentration was linear over the range of 5.0-150.0 ng ml -1 for cadmium and 5.0-150.0 ng ml -1 for lead. The limits of detection were 0.98 and 1.18 ng ml -1 for lead and cadmium ions, respectively. In simultaneous determination of Cu(II), Pb(II) and Cd(II) there are inter-metallic interactions, which result a non-linear relationship between the peak current and the ionic concentration for each of the element. Therefore, an artificial neural network was used as the multivariate calibration method. The ANN was constructed with three neurons as the output layer for the simultaneous determination of the three elements. The constructed model was able to predict the concentration of the elements in the ranges of 1.0-50.0, 5.0-200.0 and 10.0-200.0 ng ml -1 , for Cu(II), Pb(II) and Cd(II), respectively

  10. Comparison of adsorptive with extractive stripping voltammetry in electrochemical determination of retinol

    Directory of Open Access Journals (Sweden)

    Milan Sýs

    2017-01-01

    Full Text Available Adsorptive stripping voltammetry (AdSV of retinol at solid glassy carbon electrode (GCE, carbon paste electrode (CPE covered by thin layer of multi-wall carbon nanotubes (CPE/MWCNTs and carbon paste electrode covered by thin layer of single layer graphene (CPE/Graphene was compared with an extractive stripping voltammetry (ExSV into silicone oil (SO as lipophilic binder of glassy carbon paste electrode (GCPE. All types of selected working electrodes were characterized by a scanning electron microscopy to determine overall morphology of electrode surfaces together with spatial arrangement of used carbon particles. The retinol, also known as vitamin A1, was chosen as a model analyte because it is the most biologically active representative of retinoids which are classified as a significant group of lipophilic vitamins. Based on this comparison, it was observed that electrochemical method with high sensitivity (ExSV at GPCE is generally characterized by shorter linear range of the calibration curve than in case of AdSV at CPE/MWCNTs or CPE/Graphene. Unlike AdSV at solid GCE, all other tested electrochemical methods could represent suitable analytical tools for monitoring of retinoids in different types of foodstuffs. Especially, content of retinol up to tenths milligrams can be easily determined using ExSV. Additionally, negative interference of chemical species present in real samples is minimal in comparison with direct voltammetric methods performed in supporting electrolytes based on organic solvents due to application of accumulation step in "ex-situ" mode.

  11. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons.

    Science.gov (United States)

    Quesada-Peñate, I; Julcour-Lebigue, C; Jáuregui-Haza, U J; Wilhelm, A M; Delmas, H

    2012-06-30

    The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Adsorptive Stripping Voltammetric Determination of Hydroquinone using an Electrochemically Pretreated Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Abdul Niaz1,

    2008-12-01

    Full Text Available A simple and efficient adsorptive stripping voltammetric (AdSV method was developed for the determination of hydroquinone at an electrochemically pretreated glassy carbon (GC electrode in waste water. Various parameters such as solvent system, accumulation potential, accumulation time and scan rate were optimized. The electrochemically pretreated GC electrode showed good response towards hydroquinone determination by using AdSV. Under the optimized conditions the peak current showed good linear relationship with the hydroquinone concentration in the range of 0.5-4.0mg L-1 and 5-30mg L-1. The 60/40 methanol/water composition was found to be the best solvent system and 0.05mol L-1 H2SO4 was found as useful supporting electrolyte concentration. The accumulation time was 60 s and the detection limit was 50µg L-1. The developed method was successfully applied for the determination of hydroquinone in polymeric industrial discharge samples waste photographic developer solution and cream sample without any significant effect of surface fouling.

  13. From Electronic Structure to Catalytic Activity: A Single Descriptor for Adsorption and Reactivity on Transition-Metal Carbides

    DEFF Research Database (Denmark)

    Vojvodic, A.; Hellman, Anders; Ruberto, C.

    2009-01-01

    Adsorption and catalytic properties of the polar (111) surface of transition-metal carbides (TMC's) are investigated by density-functional theory. Atomic and molecular adsorption are rationalized with the concerted-coupling model, in which two types of TMC surface resonances (SR's) play key roles...

  14. Removal of radionuclides from partitioning waste solutions by adsorption and catalytic oxidation methods

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, Isao; Yamaguchi, Isoo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kubota, Masumitsu [Research Organization for Information Science and Technology (RIST), Tokai, Ibaraki (Japan)

    2000-09-01

    Adsorption of radionuclides with inorganic ion exchangers and catalytic oxidation of a complexant were studied for the decontamination of waste solutions generated in past partitioning tests with high-level liquid waste. Granulated ferrocyanide and titanic acid were used for adsorption of Cs and Sr, respectively, from an alkaline solution resulting from direct neutralization of an acidic waste solution. Both Na and Ba inhibited adsorption of Sr but Na did not that of Cs. These exchangers adsorbed Cs and Sr at low concentration with distribution coefficients of more than 10{sup 4}ml/g from 2M Na solution of pH11. Overall decontamination factors (DFs) of Cs and total {beta} nuclides exceeded 10{sup 5} and 10{sup 3}, respectively, at the neutralization-adsorption step of actual waste solutions free from a complexant. The DF of total {alpha} nuclides was less than 10{sup 3} for a waste solution containing diethylenetriaminepentaacetic acid (DTPA). DTPA was rapidly oxidized by nitric acid in the presence of a platinum catalyst, and radionuclides were removed as precipitates by neutralization of the resultant solution. The DF of {alpha} nuclides increased to 8x10{sup 4} by addition of the oxidation step. The DFs of Sb and Co were quite low through the adsorption step. A synthesized Ti-base exchanger (PTC) could remove Sb with the DF of more than 4x10{sup 3}. (author)

  15. Determination of tryptamine in foods using square wave adsorptive stripping voltammetry.

    Science.gov (United States)

    Costa, Daniel J E; Martínez, Ana M; Ribeiro, Williame F; Bichinho, Kátia M; Di Nezio, María Susana; Pistonesi, Marcelo F; Araujo, Mario C U

    2016-07-01

    Tryptamine, a biogenic amine, is an indole derivative with an electrophilic substituent at the C3 position of the pyrrole ring of the indole moiety. The electrochemical oxidation of tryptamine was investigated using glassy carbon electrode (GCE), and focusing on trace level determination in food products by square wave adsorptive stripping voltammetry (SWAdSV). The electrochemical responses of tryptamine were evaluated using differing voltammetric techniques over a wide pH range, a quasi-reversible electron-transfer to redox system represented by coupled peaks P1-P3, and an irreversible reaction for peak P2 were demonstrated. The proton and electron counts associated with the oxidation reactions were estimated. The nature of the mass transfer process was predominantly diffusion-limited for the oxidation process of P1, the most selective and sensitive analytical response (acetate buffer solution pH 5.3), being used for the development of SWAdSV method, under optimum conditions. The excellent response allowed the development of an electroanalytical method with a linear response range of from 4.7-54.5)×10(-)(8)molL(-1), low detection limit (0.8×10(-)(9)molL(-)(1)), and quantification limit (2.7×10(-9)molL(-1)), and acceptable levels of repeatability (3.6%), and reproducibility (3.8%). Tryptamine content was determined in bananas, tomatoes, cheese (mozzarella and gorgonzola), and cold meats (chicken sausage and pepperoni sausage), yielding recoveries above 90%, with excellent analytical performance using simple and low cost instrumentation. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Effect of citrate on Aspergillus niger phytase adsorption and catalytic activity in soil

    Science.gov (United States)

    Mezeli, Malika; Menezes-Blackburn, Daniel; Zhang, Hao; Giles, Courtney; George, Timothy; Shand, Charlie; Lumsdon, David; Cooper, Patricia; Wendler, Renate; Brown, Lawrie; Stutter, Marc; Blackwell, Martin; Darch, Tegan; Wearing, Catherine; Haygarth, Philip

    2015-04-01

    Current developments in cropping systems that promote mobilisation of phytate in agricultural soils, by exploiting plant-root exudation of phytase and organic acids, offer potential for developments in sustainable phosphorus use. However, phytase adsorption to soil particles and phytate complexion has been shown to inhibit phytate dephosphorylation, thereby inhibiting plant P uptake, increasing the risk of this pool contributing to diffuse pollution and reducing the potential benefits of biotechnologies and management strategies aimed to utilise this abundant reserve of 'legacy' phosphorus. Citrate has been seen to increase phytase catalytic efficiency towards complexed forms of phytate, but the mechanisms by which citrate promotes phytase remains poorly understood. In this study, we evaluated phytase (from Aspergillus niger) inactivation, and change in catalytic properties upon addition to soil and the effect citrate had on adsorption of phytase and hydrolysis towards free, precipitated and adsorbed phytate. A Langmuir model was fitted to phytase adsorption isotherms showing a maximum adsorption of 0.23 nKat g-1 (19 mg protein g-1) and affinity constant of 435 nKat gˉ1 (8.5 mg protein g-1 ), demonstrating that phytase from A.niger showed a relatively low affinity for our test soil (Tayport). Phytases were partially inhibited upon adsorption and the specific activity was of 40.44 nKat mgˉ1 protein for the free enzyme and 25.35 nKat mgˉ1 protein when immobilised. The kinetics of adsorption detailed that most of the adsorption occurred within the first 20 min upon addition to soil. Citrate had no effect on the rate or total amount of phytase adsorption or loss of activity, within the studied citrate concentrations (0-4mM). Free phytases in soil solution and phytase immobilised on soil particles showed optimum activity (>80%) at pH 4.5-5.5. Immobilised phytase showed greater loss of activity at pH levels over 5.5 and lower activities at the secondary peak at pH 2

  17. Strip biosensor for amplified detection of nerve growth factor-beta based on a molecular translator and catalytic DNA circuit.

    Science.gov (United States)

    Liu, Jun; Lai, Ting; Mu, Kejie; Zhou, Zheng

    2014-10-07

    We have demonstrated a new visual detection approach based on a molecular translator and a catalytic DNA circuit for the detection of nerve growth factor-beta (NGF-β). In this assay, a molecular translator based on the binding-induced DNA strand-displacement reaction was employed to convert the input protein to an output DNA signal. The molecular translator is composed of a target recognition element and a signal output element. Target recognition is achieved by the binding of the anti-NGF-β antibody to the target protein. Polyclonal anti-NGF-β antibody is conjugated to DNA1 and DNA2. The antibody conjugated DNA1 is initially hybridized to DNA3 to form a stable DNA1/DNA3 duplex. In the presence of NGF-β, the binding of the same target protein brings DNA1 and DNA2 into close proximity, resulting in an increase in their local effective concentration. This process triggers the strand-displacement reaction between DNA2 and DNA3 and releases the output DNA3. The released DNA3 is further amplified by a catalytic DNA circuit. The product of the catalytic DNA circuit is detected by a strip biosensor. This proposed assay has high sensitivity and selectivity with a dynamic response ranging from 10 fM to 10 pM, and its detection limit is 10 fM of NGF-β. This work provides a sensitive, enzyme-free, and universal strategy for the detection of other proteins.

  18. Lignite utilisation for binding of radionuclides and uranium determination by adsorptive stripping chronopotentiometry

    International Nuclear Information System (INIS)

    Zavodska, L.

    2010-01-01

    -cupferron on amalgam work electrode with the value of accumulation potential +200 mV (vs. Ag/AgCl). The work includes optimisation of the accumulation and regeneration time, the regeneration potential, the pH value of supporting electrolyte and concentration of used complexing agent (cupferron). The interference impacts of selected cations on uranium determination by means of adsorptive stripping chronopotentiometry (AdSC) have been also studied. The method is linear within the range of up to 50 μg dm -3 , relative standard deviation for 10 μg dm -3 of uranium is 5.2 % (n=10, accumulation time 60 s). Experimentally, the value of limit of detection was determined for uranium (1.2 μg dm -3 ) as well as the value of limit of quantification (3.6 μg dm -3 ). Using AdSC, the content of uranium was successfully determined in the sample of natural mineral water with high content of salts. The newly designed electrochemical method of determining uranium was validated by means of ICP- MS analysis and spectrophotometric determination of uranium with arsenazo III. The AdSC method may be used for uranium monitoring in waters and after potential further optimisation of sample pre-treatment also in sediments and in soil. (author)

  19. Hydrogen production from palm kernel shell via integrated catalytic adsorption (ICA) steam gasification

    International Nuclear Information System (INIS)

    Khan, Zakir; Yusup, Suzana; Ahmad, Murni Melati; Chin, Bridgid Lai Fui

    2014-01-01

    Highlights: • The paper presents integrated catalytic adsorption (ICA) steam gasification for H 2 yield. • Effects of adsorbent to biomass, biomass particle size and fluidization velocity on H 2 yield are examined. • The present study produces higher H 2 yield as compared to that obtained in literatures. • The ICA provides enhancement of H 2 yield as compared to independent catalytic and CO 2 adsorption gasification systems. - Abstract: The present study investigates the integrated catalytic adsorption (ICA) steam gasification of palm kernel shell for hydrogen production in a pilot scale atmospheric fluidized bed gasifier. The biomass steam gasification is performed in the presence of an adsorbent and a catalyst in the system. The effect of adsorbent to biomass (A/B) ratio (0.5–1.5 wt/wt), fluidization velocity (0.15–0.26 m/s) and biomass particle size (0.355–2.0 mm) are studied at temperature of 675 °C, steam to biomass (S/B) ratio of 2.0 (wt/wt) and biomass to catalyst ratio of 0.1 (wt/wt). Hydrogen composition and yield, total gas yield, and lower product gas heating values (LHV gas ) increases with increasing A/B ratio, while particle size has no significant effect on hydrogen composition and yield, total gas and char yield, gasification and carbon conversion efficiency. However, gas heating values increased with increasing biomass particle size which is due to presence of high methane content in product gas. Meanwhile, medium fluidization velocity of 0.21 m/s favoured hydrogen composition and yield. The results showed that the maximum hydrogen composition and yield of 84.62 vol% and 91.11 g H 2 /kg biomass are observed at A/B ratio of 1.5, S/B ratio of 2.0, catalyst to biomass ratio of 0.1 and temperature of 675 °C. The product gas heating values are observed in the range of 10.92–17.02 MJ/N m 3 . Gasification and carbon conversion efficiency are observed in the range of 25.66–42.95% and 20.61–41.95%, respectively. These lower

  20. Session 6: Water depollution from aniline and phenol by air oxidation and adsorptive-catalytic oxidation in liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Dobrynkin, N.M.; Batygina, M.V.; Noskov, A.S. [Boreskov Institute of Catalysis of Siberian Branch of Russian Academy of Sciences, Pr. Ak. Lavrentieva (Russian Federation)

    2004-07-01

    This paper is devoted to development of carbon catalysts and application of catalytic wet air oxidation for deep cleaning of polluted waters. The described catalysts and method are solving the problem of development environmentally reliable method for fluids treatment and allow carrying out the adsorption of pollutants on carbon CAPM (catalytically active porous material) with following regeneration of the CAPM without the loss of adsorptive qualities. The experiments have shown a principal capability simultaneously to use carbon CAPM as adsorbent and either as catalyst, or as a catalyst support for oxidation of aniline and phenol in water solutions. (authors)

  1. Evaluation of an adsorption system to concentrate VOC in air streams prior to catalytic incineration.

    Science.gov (United States)

    Campesi, María A; Luzi, Carlos D; Barreto, Guillermo F; Martínez, Osvaldo M

    2015-05-01

    Catalytic combustion is a well-developed process for the removal of volatile organic compounds (VOCs). In order to reduce both the amount of catalyst needed for incineration and the surface area of recuperative heat exchangers, an evaluation of the use of thermal swing adsorption as a previous step for VOC concentration is made. An air stream containing ethyl acetate and ethanol (employed as solvents in printing processes) has been taken as a case study. Based on the characteristics of the adsorption/desorption system and the properties of the stream to be treated, a monolithic rotor concentrator with activated carbon as adsorbent material is adopted. Once the temperature of the inlet desorption stream TD is chosen, the minimum possible desorption flow rate, WD,min, and the amount of adsorbent material can be properly defined according to the extent of the Mass Transfer Zone (MTZ) at the end of the adsorption stage. An approximate procedure to speed up the calculations needed for sizing the bed and predicting the operating variables is also presented. In the case studied here, the concentration of the VOC stream can reach 6 times that of the primary effluent when TD = 200 °C is chosen. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Support effects on adsorption and catalytic activation of O2 in single atom iron catalysts with graphene-based substrates.

    Science.gov (United States)

    Gao, Zheng-Yang; Yang, Wei-Jie; Ding, Xun-Lei; Lv, Gang; Yan, Wei-Ping

    2018-03-07

    The adsorption and catalytic activation of O 2 on single atom iron catalysts with graphene-based substrates were investigated systematically by density functional theory calculation. It is found that the support effects of graphene-based substrates have a significant influence on the stability of the single atom catalysts, the adsorption configuration, the electron transfer mechanism, the adsorption energy and the energy barrier. The differences in the stable adsorption configuration of O 2 on single atom iron catalysts with different graphene-based substrates can be well understood by the symmetrical matching principle based on frontier molecular orbital analysis. There are two different mechanisms of electron transfer, in which the Fe atom acts as the electron donor in single vacancy graphene-based substrates while the Fe atom mainly acts as the bridge for electron transfer in double vacancy graphene-based substrates. The Fermi softness and work function are good descriptors of the adsorption energy and they can well reveal the relationship between electronic structure and adsorption energy. This single atom iron catalyst with single vacancy graphene modified by three nitrogen atoms is a promising non-noble metal single atom catalyst in the adsorption and catalytic oxidation of O 2 . Furthermore, the findings can lay the foundation for the further study of graphene-based support effects and provide a guideline for the development and design of new non-noble-metal single atom catalysts.

  3. REMEDIATION OF MTBE FROM DRINKING WATER: AIR STRIPPING FOLLOWED BY OFF-GAS ADSORPTION

    Science.gov (United States)

    The widespread use of methyl tertiary butyl ether (MTBE) as an oxygenate in gasoline has resulted in the contamination of a large number of ground and surface water sources. Even though air stripping has been proven to be an effective treatment technology for MTBE removal, off-ga...

  4. Differential pulse polarography of cadmium-and lead-urate and adsorptive stripping voltammetric determination of uric acid.

    Science.gov (United States)

    Gandour, M A; Ensaf-Aboul-Kasim; Amrallah, A H; Farghaly, O A

    1994-03-01

    The complex formation between uric acid and zinc, cadmium and lead ions has been investigated using differential pulse polarography in 0.01M NaNO(3). It is found that the complexes formed by Cd(II) and Pb(II) ions with uric acid have the stoichiometry of 1:2 and the logarithmic values of the apparent stability constant are 9.47 and 11.7, respectively. On the other hand, zinc(II) ions do not give any indication of complexation with uric acid. A sensitive voltammetric method is developed for the quantitative determination of uric acid. This method is based on controlled adsorptive preconcentration of uric acid on the hanging mercury drop electrode (HMDE), followed by tracing the voltammogram in the cathodic going potential scan. The modes used are direct current stripping voltammetry (DCSV) and differential pulse stripping voltammetry (DPSV). The detection limits found were 8 x 10(-9)M (quiescent period 15 sec) by DPSV and 1.6 x 10(-8)M by DCSV.

  5. Application of adsorptive stripping voltammetry to the simultaneous determination of bismuth and copper in the presence of nuclear fast red

    International Nuclear Information System (INIS)

    Gholivand, M.B.; Romiani, A.A.

    2006-01-01

    A sensitive and selective method for the simultaneous determination of copper and bismuth by adsorptive stripping was developed using nuclear fast red (2-anthracenesulfonic acid, 4-amino-9,10-dihydro-1,3-dihydroxy-9,10-dioxo-, monosodium salt) as selective complexing agent onto hanging mercury drop electrode. In a single scan both metals gave peaks that were distinctly separated by 85 mV allowing their determination in the presence of each other. Optimal analytical conditions were found to be: nuclear fast red concentration of 80 μM, pH of 2.8 and adsorptive potential of -300 mV versus Ag/AgCl. With accumulation time of 180 s the peaks currents are proportional to concentration of copper and bismuth over the 1-100 and 5-60 ng mL -1 range with detection limits of 0.2 and 1.2 ng mL -1 , respectively. The procedure was applied to simultaneous determination of copper and bismuth in some real samples

  6. Electrochemical behavior of folic acid at calixarene based chemically modified electrodes and its determination by adsorptive stripping voltammetry

    International Nuclear Information System (INIS)

    Vaze, Vishwanath D.; Srivastava, Ashwini K.

    2007-01-01

    Voltammetric behavior of folic acid at plain carbon paste electrode and electrode modified with calixarenes has been studied. Two peaks for irreversible oxidation were observed. Out of the three calixarenes chosen for modification of the electrodes, p-tert-butyl-calix[6]arene modified electrode (CME-6) was found to have better sensitivity for folic acid. Chronocoulometric and differential pulse voltammetric studies reveal that folic acid can assemble at CME-6 to form a monolayer whose electron transfer rate is 0.00273 s -1 with 2-electron/2-proton transfer for the peak at +0.71 V against SCE. An adsorption equilibrium constant of 5 x 10 3 l/mol for maximum surface coverage of 2.89 x 10 -10 mol/cm 2 was obtained. The current is found to be rectilinear with concentration by differential pulse voltammetry. However, linearity in the lower range of concentration 8.79 x 10 -12 M to 1.93 x 10 -9 M with correlation coefficient of 0.9920 was achieved by adsorptive stripping voltammetry. The limit of detection obtained was found to be 1.24 x 10 -12 M. This method was used for the determination of folic acid in a variety of samples, viz. serum, asparagus, spinach, oranges and multivitamin preparations

  7. Electrochemical behavior of folic acid at calixarene based chemically modified electrodes and its determination by adsorptive stripping voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Vaze, Vishwanath D. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Srivastava, Ashwini K. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India)], E-mail: aksrivastava@chem.mu.ac.in

    2007-12-31

    Voltammetric behavior of folic acid at plain carbon paste electrode and electrode modified with calixarenes has been studied. Two peaks for irreversible oxidation were observed. Out of the three calixarenes chosen for modification of the electrodes, p-tert-butyl-calix[6]arene modified electrode (CME-6) was found to have better sensitivity for folic acid. Chronocoulometric and differential pulse voltammetric studies reveal that folic acid can assemble at CME-6 to form a monolayer whose electron transfer rate is 0.00273 s{sup -1} with 2-electron/2-proton transfer for the peak at +0.71 V against SCE. An adsorption equilibrium constant of 5 x 10{sup 3} l/mol for maximum surface coverage of 2.89 x 10{sup -10} mol/cm{sup 2} was obtained. The current is found to be rectilinear with concentration by differential pulse voltammetry. However, linearity in the lower range of concentration 8.79 x 10{sup -12} M to 1.93 x 10{sup -9} M with correlation coefficient of 0.9920 was achieved by adsorptive stripping voltammetry. The limit of detection obtained was found to be 1.24 x 10{sup -12} M. This method was used for the determination of folic acid in a variety of samples, viz. serum, asparagus, spinach, oranges and multivitamin preparations.

  8. Adsorption of acetanilide herbicides on soil and its components. II. Adsorption and catalytic hydrolysis of diethatyl-ethyl on saturated Na(+)-, K(+)-, Ca(2+)-, and Mg(2+)-montmorillonite.

    Science.gov (United States)

    Liu, W P; Fang, Z; Liu, H J; Yang, W C

    2001-04-01

    Adsorption and catalytic hydrolysis of the herbicide diethatyl-ethyl [N-chloroacetyl-N-(2,6-diethylphenyl)glycine ethyl ester] on homoionic Na(+)-, K(+)-, Ca(2+)-, and Mg(2+)-montmorillonite clays were investigated in water solution. The Freundlich adsorption coefficient, Ki, got from isotherms on clay followed the order of Na+ approximately K+ > Mg2+ approximately Ca2+. Analysis of FT-IR spectra of diethatyl-ethyl adsorbed on clay suggests probable bonding at the carboxyl and amide carbonyl groups of the herbicide. The rate of herbicide hydrolysis in homoionic clay suspensions followed the same order as that for adsorption, indicating that adsorption may have preceded and thus caused hydrolysis. Preliminary product identification showed that hydrolysis occurred via nucleophilic substitution at the carboxyl carbon, causing the cleavage of the ester bond and formation of diethatyl and its dechlorinated derivative, and at the amide carbon, yielding an ethyl ester derivative and its acid. These pathways also suggest that hydrolysis of diethatyl-ethyl was catalyzed by adsorption on the clay surface.

  9. A square-wave adsorptive stripping voltammetric method for the determination of Amaranth, a food additive dye.

    Science.gov (United States)

    Alghamdi, Ahmad H

    2005-01-01

    Square-wave adsorptive stripping voltammetric (AdSV) determinations of trace concentrations of the azo coloring agent Amaranth are described. The analytical methodology used was based on the adsorptive preconcentration of the dye on the hanging mercury drop electrode, followed by initiation of a negative sweep. In a pH 10 carbonate supporting electrolyte, Amaranth gave a well-defined and sensitive AdSV peak at -518 mV. The electroanalytical determination of this azo dye was found to be optimal in carbonate buffer (pH 10) under the following experimental conditions: accumulation time, 120 s; accumulation potential, 0.0 V; scan rate, 600 mV/s; pulse amplitude, 90 mV; and frequency, 50 Hz. Under these optimized conditions the AdSV peak current was proportional over the concentration range 1 x 10(-8)-1.1 x 10(-7) mol/L (r = 0.999) with a detection limit of 1.7 x 10(-9) mol/L (1.03 ppb). This analytical approach possessed enhanced sensitivity, compared with conventional liquid chromatography or spectrophotometry and it was simple and fast. The precision of the method, expressed as the relative standard deviation, was 0.23%, whereas the accuracy, expressed as the mean recovery, was 104%. Possible interferences by several substances usually present as food additive azo dyes (E110, E102), gelatin, natural and artificial sweeteners, preservatives, and antioxidants were also investigated. The developed electroanalyticals method was applied to the determination of Amaranth in soft drink samples, and the results were compared with those obtained by a reference spectrophotometric method. Statistical analysis (paired t-test) of these data showed that the results of the 2 methods compared favorably.

  10. Adsorptive stripping voltammetric determination of nitroimidazole derivative on multiwalled carbon nanotube modified electrodes: influence of size and functionalization of nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Jara-Ulloa, Paola; Canete-Rosales, Paulina; Nunez-Vergara, Luis J; Squella, Juan A., E-mail: asquella@ciq.uchile.c [University of Chile, Santiago (Chile). Chemical and Pharmaceutical Sciences Faculty. Bioelectrochemistry Lab.

    2011-07-01

    1-Methyl-4-nitro-2-bromine methylimidazole (4-NimMeBr), was electrochemically reduced on mercury, glassy carbon and multiwalled carbon nanotubes (MWCNT) modified electrodes. 4-NimMeBr was adsorbed on the MWCNT modified electrode thus permitting the implementation of an adsorptive stripping voltammetric (ASV) method. We have used 4-NimMeBr as a prototype electroactive nitro compound to study the effect of both the size of the nanotubes and its functionalization by oxidation. The oxidized MWCNT forms better dispersions than the non-oxidized, producing electrode surface with higher density of MWCNT as was determined by electrochemical mapping using scanning electrochemical microscopy (SECM). Under the optimized conditions, the peak current was proportional to the concentration of 4-NimMeBr in the range of 10{sup -6} mol L{sup -1} to 10{sup -4} mol L{sup -1} with detection and quantification limits of 4.41 x 10{sup -6} mol L{sup -1} and 6.21 x 10{sup -6} mol L{sup -1}, respectively. The sensibility of bare electrode was 0.01 {mu}A per mmol L{sup -1}, which was lower than the value of 5.34 and 6.97 mA per mmol L{sup -1} obtained using short and large oxidized MWCNT, respectively. (author)

  11. Solar UV-assisted sample preparation of river water for ultra-trace determination of uranium by adsorptive stripping voltammetry

    International Nuclear Information System (INIS)

    Woldemichael, G.; Tulu, T.; Flechsig, G.-U.

    2012-01-01

    The article describes how solar ultraviolet-A radiation can be used to digest samples as needed for voltammetric ultratrace determination of uranium(VI) in river water. We applied adsorptive stripping voltammetry (AdSV) using chloranilic acid as the complexing agent. Samples from the river Warnow in Rostock (Germany) were pretreated with either soft solar UV or wit artificial hard UV from a 30-W source emitting 254-nm light. Samples were irradiated for 12 h, and both methods yielded the same results. We were able to detect around 1 μg.L -1 of uranium(VI) in a sample of river water that also contained dissolved organic carbon at a higher mg.L -1 levels. No AdSV signal was obtained for U(VI) without any UV pre-treatment. Pseudo-polarographic experiments confirmed the dramatic effect of both digestion techniques the the AdSV response. The new method is recommended for use in mobile ultratrace voltammetry of heavy metals for most kinds of natural water samples including tap, spring, ground, sea, and river waters. The direct use of solar radiation for sample pre-treatment represents a sustainable technique for sample preparation that does not consume large quantities of chemicals or energy. (author)

  12. Determination of Xanthine in the Presence of Hypoxanthine by Adsorptive Stripping Voltammetry at the Mercury Film Electrode

    Directory of Open Access Journals (Sweden)

    Percio Augusto Mardini Farias

    2014-01-01

    Full Text Available A stripping method for the determination of xanthine in the presence of hypoxanthine at the submicromolar concentration levels is described. The method is based on controlled adsorptive accumulation at the thin-film mercury electrode followed by a fast linear scan voltammetric measurement of the surface species. Optimum experimental conditions were found to be the use of 1.0 × 10 −3 mol L −1 NaOH solution as supporting electrolyte, an accumulation potential of 0.00 V for xanthine and −0.50 V for hypoxanthine–copper, and a linear scan rate of 200 mV second −1 . The response of xanthine is linear over the concentration ranges of 20-140 ppb. For an accumulation time of 30 minutes, the detection limit was found to be 36 ppt (2.3 × 10 −10 mol L −1 . Adequate conditions for measuring the xanthine in the presence of hypoxanthine, copper and other metals, uric acid, and other nitrogenated bases were also investigated. The utility of the method is demonstrated by the presence of xanthine associated with hypoxanthine, uric acid, nitrogenated bases, ATP, and ssDNA.

  13. Adsorptive stripping differential pulse voltammetric determination of venlafaxine and desvenlafaxine employing Nafion-carbon nanotube composite glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Sanghavi, Bankim J. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400 098, Maharashtra (India); Srivastava, Ashwini K., E-mail: aksrivastava@chem.mu.ac.i [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400 098, Maharashtra (India)

    2011-04-15

    A Nafion-carbon nanotube-modified glassy carbon electrode (NAF-CNT-GCE) was developed for the determination of venlafaxine (VF) and desvenlafaxine (DVF). The electrochemical behavior of both these molecules was investigated employing cyclic voltammetry (CV), chronocoulometry (CC), electrochemical impedance spectroscopy (EIS) and adsorptive stripping differential pulse voltammetry (AdSDPV). The surface morphology of the electrodes has been studied by means of scanning electron microscopy (SEM). These studies revealed that the oxidation of VF and DVF is facilitated at NAF-CNT-GCE. After optimization of analytical conditions employing this electrode at pH 7.0 in Britton-Robinson buffer (0.05 M) for VF and pH 5.0 in acetate buffer (0.1 M) for DVF, the peak currents for both the molecules were found to vary linearly with their concentrations in the range of 3.81 x 10{sup -8}-6.22 x 10{sup -5} M for VF and 5.33 x 10{sup -8}-3.58 x 10{sup -5} M for DVF. The detection limits (S/N = 3) of 1.24 x 10{sup -8} and 2.11 x 10{sup -8} M were obtained for VF and DVF, respectively, using AdSDPV. The prepared modified electrode showed several advantages, such as simple preparation method, high sensitivity, very low detection limits and excellent reproducibility. The proposed method was employed for the determination of VF and DVF in pharmaceutical formulations, urine and blood serum samples.

  14. Adsorption and bio-sorption of nickel ions and reuse for 2-chlorophenol catalytic ozonation oxidation degradation from water

    International Nuclear Information System (INIS)

    Ma, Wei; Zong, Panpan; Cheng, Zihong; Wang, Baodong; Sun, Qi

    2014-01-01

    Highlights: • Biomass and fly ash which were widespread for adsorption of heavy metal ions. • Preparation of catalyst by saturated adsorbents for 2-chlorophenol ozone degradation. • This work demonstrated that the O 3 /catalyst process was an effective pathway. • The use of nickel ions, fly ash and sawdust to achieve the recycling utilization of resources. -- Abstract: This work explored the preparation of an effective and low-cost catalyst and investigated its catalytic capacity for 2-chlorophenol ozonation oxidation degradation in wastewater by using an ozone oxidation batch reactor. The catalyst was directly prepared by the reuse of fly ash and sawdust after saturated adsorption of nickel ions from wastewater, which was proposed as an efficient and economic approach. The obtained catalyst was characterized by TGA, BET, FTIR, XRD, and SEM, the results showed that fly ash as the basic framework has high specific surface area and the addition of sawdust as the porogen agent could improve the pore structure of the catalyst. The adsorption of nickel ions by fly ash and sawdust from aqueous solution was also investigated in this study. The results obtained from the experiments indicated that adsorption of nickel ions by fly ash and biomass sawdust could be well described by Langmuir isotherm model and pseudo second order kinetic model. The catalytic performance of catalyst was studied in terms of the effect of time, liquid–solid ratio and pH on 2-chlorophenol ozonation degradation. It was found that the catalyst could effectively improve the ozonation reaction rate at pH = 7 with a 2:1 liquid–solid ratio. The kinetic study demonstrated that the reaction followed the first order model, and the rate constant increased 267% (0.03–0.1 min −1 ) of 2-chlorophenol ozonation degradation with 5 mmol/L concentration at pH = 7.0 compared with ozonation alone

  15. Adsorption and bio-sorption of nickel ions and reuse for 2-chlorophenol catalytic ozonation oxidation degradation from water

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Wei, E-mail: chmawv@yahoo.com [School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Zong, Panpan; Cheng, Zihong [School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, Baodong; Sun, Qi [National Institute of Clean-and-low Carbon Energy, Beijing 102209 (China)

    2014-02-15

    Highlights: • Biomass and fly ash which were widespread for adsorption of heavy metal ions. • Preparation of catalyst by saturated adsorbents for 2-chlorophenol ozone degradation. • This work demonstrated that the O{sub 3}/catalyst process was an effective pathway. • The use of nickel ions, fly ash and sawdust to achieve the recycling utilization of resources. -- Abstract: This work explored the preparation of an effective and low-cost catalyst and investigated its catalytic capacity for 2-chlorophenol ozonation oxidation degradation in wastewater by using an ozone oxidation batch reactor. The catalyst was directly prepared by the reuse of fly ash and sawdust after saturated adsorption of nickel ions from wastewater, which was proposed as an efficient and economic approach. The obtained catalyst was characterized by TGA, BET, FTIR, XRD, and SEM, the results showed that fly ash as the basic framework has high specific surface area and the addition of sawdust as the porogen agent could improve the pore structure of the catalyst. The adsorption of nickel ions by fly ash and sawdust from aqueous solution was also investigated in this study. The results obtained from the experiments indicated that adsorption of nickel ions by fly ash and biomass sawdust could be well described by Langmuir isotherm model and pseudo second order kinetic model. The catalytic performance of catalyst was studied in terms of the effect of time, liquid–solid ratio and pH on 2-chlorophenol ozonation degradation. It was found that the catalyst could effectively improve the ozonation reaction rate at pH = 7 with a 2:1 liquid–solid ratio. The kinetic study demonstrated that the reaction followed the first order model, and the rate constant increased 267% (0.03–0.1 min{sup −1}) of 2-chlorophenol ozonation degradation with 5 mmol/L concentration at pH = 7.0 compared with ozonation alone.

  16. Adsorptive accumulation in constant current stripping chronopotentiometry as an alternative for the electrochemical study of metal complexation by thiol–containing peptides

    Czech Academy of Sciences Publication Activity Database

    Serrano, N.; Šestáková, Ivana; Diaz-Cruz, J. M.; Arino, C.

    2006-01-01

    Roč. 591, č. 1 (2006), s. 105-117 ISSN 0022-0728 R&D Projects: GA MŠk OC D21.002 Grant - others:Spanish Ministry of Science and Technology(ES) BQU2003-07587-C02-01; Generalitat de Catalunya(ES) 2001SGR-00056 Institutional research plan: CEZ:AV0Z40400503 Keywords : stripping chronopotentiometry * adsorptive accumulation * phytochelatins * glutathione Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.339, year: 2006

  17. The redox behaviour of diazepam (Valium®) using a disposable screen-printed sensor and its determination in drinks using a novel adsorptive stripping voltammetric assay.

    Science.gov (United States)

    Honeychurch, Kevin C; Crew, Adrian; Northall, Hannah; Radbourne, Stuart; Davies, Owian; Newman, Sam; Hart, John P

    2013-11-15

    In this study we investigated the possibility of applying disposable electrochemical screen-printed carbon sensors for the rapid identification and quantitative determination of diazepam in beverages. This was achieved utilising a previously unreported oxidation peak. The origin of this peak was investigated further by cyclic voltammetry and gas chromatography/mass spectroscopy. At pH 6 the voltammetric behaviour of this oxidation process was found to involve adsorption of the drug allowing for the development of an adsorptive stripping voltammetric assay. Experimental conditions were then optimised for the determination of diazepam in a beverage sample using a medium exchange technique. It was shown that no elaborate extraction procedures were required as the calibration plots obtained in the absence and presence of the beverage were very similar. © 2013 Elsevier B.V. All rights reserved.

  18. Nanomolar detection of rutin based on adsorptive stripping analysis at single-sided heated graphite cylindrical electrodes with direct current heating

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shao-Hua; Sun, Jian-Jun; Zhang, De-Feng; Lin, Zhi-Bin; Nie, Fa-Hui; Qiu, He-Yuan; Chen, Guo-Nan [Key Laboratory of Analysis and Detection Technology for Food Safety, Ministry of Education, College of Chemistry and Chemical Engineering, Fuzhou University, 523 Gong Ye Road, Fuzhou 350002 (China)

    2008-09-20

    A single-sided heated graphite cylindrical electrode (ss-HGCE) was designed. Compared to previous alternative current (AC) heating, much simpler and cheaper direct current (DC) heating supplier was adopted for the first time to perform adsorptive accumulation of rutin at ss-HGCE at elevated electrode temperature. This offers great promise for low cost, miniaturization and high compatibility with portability. The square wave voltammetry (SWV) stripping peak current was enhanced with increasing the electrode temperature only during preconcentration step. This enhancement was contributed to the forced thermal convection induced by heating the electrode rather than the bulk solution, which is able to improve mass transfer and facilitate adsorption hence enhance stripping response. A detection limit of 1.0 x 10{sup -9} M (S/N = 3) could be obtained at an electrode temperature of 48 C during 5 min accumulation, one magnitude lower than that at 28 C (room temperature). This is the lowest value at carbon-based electrodes for rutin determination as we know. Such novel method was also successfully used to determine rutin in pharmaceutical tablets. (author)

  19. Electrochemical determination of resveratrol in dietary supplements at a boron-doped diamond electrode in the presence of hexadecyltrimethylammonium bromide using square-wave adsorptive stripping voltammetry

    Directory of Open Access Journals (Sweden)

    Yardim Yavuz

    2017-01-01

    Full Text Available A sensitive electroanalytical methodology for the determination of resveratrol is presented for the first time using adsorptive stripping voltammetry at a bare boron-doped diamond (BDD electrode. In cyclic voltammetry, resveratrol shows one irreversible and an adsorption-controlled oxidation peak at a BDD electrode. The voltammetric results indicated that in the presence of hexadecyl trimethyl ammonium bromide, the BDD electrode remarkably enhanced the oxidation of resveratrol, which leads to an improvement in the peak current with a shift of the peak potential to more positive values. Using the square-wave stripping mode, the compound yielded a well-defined voltammetric response in 0.1 M nitric acid solution containing 100 μmol L-1 hexadecyl trimethyl ammonium bromide at 0.74 V (vs. Ag/AgCl, after 60 s accumulation at the open-circuit condition. A linear calibration graph was obtained in the concentration range 0.025 to 60.0 μg mL-1, with a detection limit of 0.0063 μg mL-1. The applicability of the proposed method was verified by analysis of resveratrol in commercial dietary supplements.

  20. Removal of ethylene from air stream by adsorption and plasma-catalytic oxidation using silver-based bimetallic catalysts supported on zeolite.

    Science.gov (United States)

    Trinh, Quang Hung; Lee, Sang Baek; Mok, Young Sun

    2015-03-21

    Dynamic adsorption of ethylene on 13X zeolite-supported Ag and Ag-M(x)O(y) (M: Co, Cu, Mn, and Fe), and plasma-catalytic oxidation of the adsorbed ethylene were investigated. The experimental results showed that the incorporation of Ag into zeolite afforded a marked enhancement in the adsorptivity for ethylene. The addition of transition metal oxides was found to have a positive influence on the ethylene adsorption, except Fe(x)O(y). The presence of the additional metal oxides, however, appeared to somewhat interrupt the diffusion of ozone into the zeolite micro-pores, leading to a decrease in the plasma-catalytic oxidation efficiency of the ethylene adsorbed there. Among the second additional metal oxides, Fe(x)O(y) was able to reduce the emission of ozone during the plasma-catalytic oxidation stage while keeping a high effectiveness for the oxidative removal of the adsorbed ethylene. The periodical treatment consisting of adsorption followed by plasma-catalytic oxidation may be a promising energy-efficient ethylene abatement method. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Complexation-Based Detection of Nickel(II at a Graphene-Chelate Probe in the Presence of Cobalt and Zinc by Adsorptive Stripping Voltammetry

    Directory of Open Access Journals (Sweden)

    Keagan Pokpas

    2017-07-01

    Full Text Available The adsorptive stripping voltammetric detection of nickel and cobalt in water samples at metal film electrodes has been extensively studied. In this work, a novel, environmentally friendly, metal-free electrochemical probe was constructed for the ultra-trace determination of Ni2+ in water samples by Adsorptive Cathodic Stripping Voltammetry (AdCSV. The electrochemical platform is based on the adsorptive accumulation of Ni2+ ions directly onto a glassy carbon electrode (GCE modified with dimethylglyoxime (DMG as chelating agent and a Nafion-graphene (NGr nanocomposite to enhance electrode sensitivity. The nafion-graphene dimethylglyoxime modified glassy carbon electrode (NGr-DMG-GCE shows superior detection capabilities as a result of the improved surface-area-to-volume ratio and enhanced electron transfer kinetics following the incorporation of single layer graphene, while limiting the toxic effects of the sensor by removal of the more common mercury, bismuth and lead films. Furthermore, for the first time the NGr-DMG-GCE, in the presence of common interfering metal ions of Co2+ and Zn2+ demonstrates good selectivity and preferential binding towards the detection of Ni2+ in water samples. Structural and morphological characterisation of the synthesised single layer graphene sheets was conducted by Raman spectrometry, HRTEM and HRSEM analysis. The instrumental parameters associated with the electrochemical response, including accumulation potential and accumulation time were investigated and optimised in addition to the influence of DMG and graphene concentrations. The NGr-DMG-GCE demonstrated well resolved, reproducible peaks, with RSD (% below 5% and a detection limit of 1.5 µg L−1 for Ni2+ reduction at an accumulation time of 120 s., the prepared electrochemical sensor exhibited good detection and quantitation towards Ni2+ detection in tap water samples, well below 0.1 mg L−1 set by the WHO and EPA standards. This comparable to the South

  2. Complexation-Based Detection of Nickel(II) at a Graphene-Chelate Probe in the Presence of Cobalt and Zinc by Adsorptive Stripping Voltammetry.

    Science.gov (United States)

    Pokpas, Keagan; Jahed, Nazeem; Baker, Priscilla G; Iwuoha, Emmanuel I

    2017-07-25

    The adsorptive stripping voltammetric detection of nickel and cobalt in water samples at metal film electrodes has been extensively studied. In this work, a novel, environmentally friendly, metal-free electrochemical probe was constructed for the ultra-trace determination of Ni 2+ in water samples by Adsorptive Cathodic Stripping Voltammetry (AdCSV). The electrochemical platform is based on the adsorptive accumulation of Ni 2+ ions directly onto a glassy carbon electrode (GCE) modified with dimethylglyoxime (DMG) as chelating agent and a Nafion-graphene (NGr) nanocomposite to enhance electrode sensitivity. The nafion-graphene dimethylglyoxime modified glassy carbon electrode (NGr-DMG-GCE) shows superior detection capabilities as a result of the improved surface-area-to-volume ratio and enhanced electron transfer kinetics following the incorporation of single layer graphene, while limiting the toxic effects of the sensor by removal of the more common mercury, bismuth and lead films. Furthermore, for the first time the NGr-DMG-GCE, in the presence of common interfering metal ions of Co 2+ and Zn 2+ demonstrates good selectivity and preferential binding towards the detection of Ni 2+ in water samples. Structural and morphological characterisation of the synthesised single layer graphene sheets was conducted by Raman spectrometry, HRTEM and HRSEM analysis. The instrumental parameters associated with the electrochemical response, including accumulation potential and accumulation time were investigated and optimised in addition to the influence of DMG and graphene concentrations. The NGr-DMG-GCE demonstrated well resolved, reproducible peaks, with RSD (%) below 5% and a detection limit of 1.5 µg L -1 for Ni 2+ reduction at an accumulation time of 120 s., the prepared electrochemical sensor exhibited good detection and quantitation towards Ni 2+ detection in tap water samples, well below 0.1 mg L -1 set by the WHO and EPA standards. This comparable to the South African

  3. Adsorption and catalytic hydrolysis of carbaryl and atrazine on pig manure-derived biochars: Impact of structural properties of biochars

    International Nuclear Information System (INIS)

    Zhang, Peng; Sun, Hongwen; Yu, Li; Sun, Tieheng

    2013-01-01

    Highlights: ► High ash content biochar can increase solution pH and released metal ions. ► Ash in biochar can combine pesticide through specific interactions. ► Composition and structure of biochar is favor for the hydrolysis of pesticides. -- Abstract: Biochars were produced from pig manure to elucidate the influence of biochars with high ash contents on the fate of pesticides. Adsorption and catalytic hydrolysis of carbaryl and atrazine on original biochars and deashed biochars were investigated. The two pesticides were substantially adsorbed by the biochars, with organic carbon normalized sorption coefficient (K oc ) values of 10 2.65 –10 3.66 L/kg for carbaryl and 10 1.90 –10 3.57 L/kg for atrazine at C e of 0.5 mg/L. Hydrophobic effect alone could not explain the sorption, and several other processes including pore-filling and π–π electron donor–acceptor interactions were involved in pesticide adsorption. Adsorption increased greatly on the deashed biochar, indicating that some organic sorption sites in the original biochars were blocked or difficult to access due to their interactions with inorganic moiety. The pesticides were found to hydrolyze faster in the presence of biochars, and in the presence of biochar pyrolyzed at 700 °C, carbaryl and atrazine were decomposed by 71.8% and 27.9% in 12 h, respectively. The elevated solution pH was the main reason for the enhanced hydrolysis; however both the mineral surface and dissolved metal ions released from the biochars were confirmed to catalyze the hydrolysis

  4. Adsorption and catalytic hydrolysis of carbaryl and atrazine on pig manure-derived biochars: Impact of structural properties of biochars

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peng, E-mail: phevos1983@yahoo.com.cn [MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071 (China); Sun, Hongwen, E-mail: sunhongwen@nankai.edu.cn [MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071 (China); Yu, Li [MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071 (China); Sun, Tieheng [Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China)

    2013-01-15

    Highlights: ► High ash content biochar can increase solution pH and released metal ions. ► Ash in biochar can combine pesticide through specific interactions. ► Composition and structure of biochar is favor for the hydrolysis of pesticides. -- Abstract: Biochars were produced from pig manure to elucidate the influence of biochars with high ash contents on the fate of pesticides. Adsorption and catalytic hydrolysis of carbaryl and atrazine on original biochars and deashed biochars were investigated. The two pesticides were substantially adsorbed by the biochars, with organic carbon normalized sorption coefficient (K{sub oc}) values of 10{sup 2.65}–10{sup 3.66} L/kg for carbaryl and 10{sup 1.90}–10{sup 3.57} L/kg for atrazine at C{sub e} of 0.5 mg/L. Hydrophobic effect alone could not explain the sorption, and several other processes including pore-filling and π–π electron donor–acceptor interactions were involved in pesticide adsorption. Adsorption increased greatly on the deashed biochar, indicating that some organic sorption sites in the original biochars were blocked or difficult to access due to their interactions with inorganic moiety. The pesticides were found to hydrolyze faster in the presence of biochars, and in the presence of biochar pyrolyzed at 700 °C, carbaryl and atrazine were decomposed by 71.8% and 27.9% in 12 h, respectively. The elevated solution pH was the main reason for the enhanced hydrolysis; however both the mineral surface and dissolved metal ions released from the biochars were confirmed to catalyze the hydrolysis.

  5. Synthesis and characterization of kaolin assisted metal nanocomposite and its tremendous adsorptive and photo catalytic applications

    International Nuclear Information System (INIS)

    Tahir, H.; Saad, M.; Saleem, U.

    2018-01-01

    The present work demonstrates the synthesis of Kaolin assisted Ag nanocomposite (Ag-KNC) by co-precipitation method. The surface morphology of them was studied through SEM and chemical constituents by EDS techniques. The removal of efficaciousness of Ag-KNC was tested by Malachite Green Oxalate (MGO) dye through batch adsorption and photocatalytic strategies. The sorption experiments were preceded under the optimized conditions like amount of adsorbent, stay time and pH. The feasibility of the process was determined by employing Freundlich, Langmuir and D-R (Dubinin –Radushkevich) adsorption isotherms. The pH at point of zero charge (pHpzc) was conjointly calculable to work out the surface neutrality of the system. The salt effect for the removal of MGO dye was investigated. Thermodynamic parameters like free energy (∆Go), entropy (∆So) and enthalpy (∆Ho), of the system was investigated. Adsorption Kinetic was resolute by Intra particle diffusion (IPD) and Boyd’s models. An attempt was made to prepare (Ag-KCN) nanophoto catalyst by UV light assisted degradation of Malachite Green Oxalate (MGO) dye. They were prepared by the reduction of Ag+ ion under alkaline conditions on kaolin surface. The photo degradation (PD) process was initiated by photo generated electrons. The present study recommended that projected strategies were successfully applied for the remediation of environmental problems. (author)

  6. Polyvinylpyrrolidone adsorption effects on the morphologies of synthesized platinum particles and its catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Ooi, Mahayatun Dayana Johan [Nano - Optoelectronic Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800, Minden, Pulau Pinang (Malaysia); Aziz, Azlan Abdul [Nano - Optoelectronic Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800, Minden, Pulau Pinang (Malaysia); Nanobiotechnology Research and Innovation (NanoBRI), INFORMM, Universiti Sains Malaysia, 11800, Minden, Pulau Pinang (Malaysia)

    2015-04-24

    Flower-like Platinum micro-structures were synthesized from different concentration of the PVP using solvothermal method. At 5.0×10{sup −3} mmol of PVP, well-defined flower-like pattern consists of triangular petals radiating from the centre were produced whereas larger flower network developed at higher PVP concentration. High degree of crystallinity was obtained upon each increment of PVP. The well defined flower like pattern synthesized using 5.0×10{sup −3} mmol PVP exhibit the highest catalytic activity and stability towards electro-oxidation of formic acid.

  7. Using of multi-walled carbon nanotubes electrode for adsorptive stripping voltammetric determination of ultratrace levels of RDX explosive in the environmental samples.

    Science.gov (United States)

    Rezaei, Behzad; Damiri, Sajjad

    2010-11-15

    A study of the electrochemical behavior and determination of RDX, a high explosive, is described on a multi-walled carbon nanotubes (MWCNTs) modified glassy carbon electrode (GCE) using adsorptive stripping voltammetry and electrochemical impedance spectroscopy (EIS) techniques. The results indicated that MWCNTs electrode remarkably enhances the sensitivity of the voltammetric method and provides measurements of this explosive down to the sub-mg/l level in a wide pH range. The operational parameters were optimized and a sensitive, simple and time-saving cyclic voltammetric procedure was developed for the analysis of RDX in ground and tap water samples. Under optimized conditions, the reduction peak have two linear dynamic ranges of 0.6-20.0 and 8.0-200.0 mM with a detection limit of 25.0 nM and a precision of <4% (RSD for 8 analysis). Copyright © 2010 Elsevier B.V. All rights reserved.

  8. METHANOL REMOVAL FROM METHANOL-WATER MIXTURE USING ACTIVATED SLUDGE, AIR STRIPPING AND ADSORPTION PROCESS: COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    SALAM K. AL-DAWERY

    2015-12-01

    Full Text Available An experimental research has been carried out in order to examine the removal of methanol from methanol-water mixtures using three different methods; activated sludge; activated carbon and air stripping. The results showed that the methanol was totally consumed by the bacteria as quickly as the feed entered the activated sludge vessel. Air stripping process has a limited ability for removing of methanol due to strong intermolecular forces between methanol and water; however, the results showed that the percentage of methanol removed using air pressure at 0.5 bar was higher than that of using air pressure of 0.25 bar. Removal of methanol from the mixture with a methanol content of 5% using activated carbon was not successful due to the limited capacity of the of the activated carbon. Thus, the activated sludge process can be considered as the most suitable process for the treatment of methanol-water mixtures.

  9. Factors affecting hydrocarbon removal by air stripping

    International Nuclear Information System (INIS)

    McFarland, W.E.

    1992-01-01

    This paper includes an overview of the theory of air stripping design considerations and the factors affecting stripper performance. Effects of temperature, contaminant characteristics, stripping tower geometry and air/water ratios on removal performance are discussed. The discussion includes treatment of groundwater contaminated with petroleum hydrocarbons and chlorinated solvents such as TCE and PCE. Control of VOC emissions from air strippers has become a major concern in recent years, due to more stringent restrictions on air quality in many areas. This paper includes an overview of available technology to control air emissions (including activated carbon adsorption, catalytic oxidation and steam stripping) and the effects of air emission control on overall efficiency of the treatment process. The paper includes an overview of the relative performance of various packing materials for air strippers and explains the relative advantages and disadvantages of comparative packing materials. Field conditions affecting selection of packing materials are also discussed. Practical guidelines for the design of air stripping systems are presented, as well as actual case studies of full-scale air stripping projects

  10. Adsorptive Stripping Voltammetric Determination of Amaranth and Tartrazine in Drinks and Gelatins Using a Screen-Printed Carbon Electrode

    Science.gov (United States)

    Perdomo, Yeny; Arancibia, Verónica; Nagles, Edgar

    2017-01-01

    A fast, sensitive, and selective method for the simultaneous determination of one pair of synthetic colorants commonly found mixed in food products, Amaranth (AM) and Tartrazine (TZ), based on their adsorption and oxidation on a screen-printed electrode (SPE) is presented. The variation of peak current with pH, supporting electrolyte, adsorption time, and adsorption potential were optimized using square wave adsorptive voltammetry. The optimal conditions were found to be: pH 3.2 (PBS), Eads 0.00 V, and tads 30 s. Under these conditions, the AM and TZ signals were observed at 0.56 and 0.74 V, respectively. A linear response were found over the 0.15 to 1.20 µmol L−1 and 0.15 to 0.80 µmol L−1 concentrations, with detection limits (3σ/slope) of 26 and 70 nmol L−1 for AM and TZ, respectively. Reproducibility for 17.7 µmol L–1 AM and TZ solutions were 2.5 and 3.0% (n = 7), respectively, using three different electrodes. The method was validated by determining AM and TZ in spiked tap water and unflavored gelatin spiked with AM and TZ. Because a beverage containing both AM and TZ was not found, the method was applied to the determination of AM in a kola soft drink and TZ in an orange jelly and a soft drink powder. PMID:29156561

  11. Adsorptive Stripping Voltammetric Determination of Amaranth and Tartrazine in Drinks and Gelatins Using a Screen-Printed Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Yeny Perdomo

    2017-11-01

    Full Text Available A fast, sensitive, and selective method for the simultaneous determination of one pair of synthetic colorants commonly found mixed in food products, Amaranth (AM and Tartrazine (TZ, based on their adsorption and oxidation on a screen-printed electrode (SPE is presented. The variation of peak current with pH, supporting electrolyte, adsorption time, and adsorption potential were optimized using square wave adsorptive voltammetry. The optimal conditions were found to be: pH 3.2 (PBS, Eads 0.00 V, and tads 30 s. Under these conditions, the AM and TZ signals were observed at 0.56 and 0.74 V, respectively. A linear response were found over the 0.15 to 1.20 µmol L−1 and 0.15 to 0.80 µmol L−1 concentrations, with detection limits (3σ/slope of 26 and 70 nmol L−1 for AM and TZ, respectively. Reproducibility for 17.7 µmol L–1 AM and TZ solutions were 2.5 and 3.0% (n = 7, respectively, using three different electrodes. The method was validated by determining AM and TZ in spiked tap water and unflavored gelatin spiked with AM and TZ. Because a beverage containing both AM and TZ was not found, the method was applied to the determination of AM in a kola soft drink and TZ in an orange jelly and a soft drink powder.

  12. Adsorptive Stripping Voltammetric Determination of Amaranth and Tartrazine in Drinks and Gelatins Using a Screen-Printed Carbon Electrode.

    Science.gov (United States)

    Perdomo, Yeny; Arancibia, Verónica; García-Beltrán, Olimpo; Nagles, Edgar

    2017-11-18

    A fast, sensitive, and selective method for the simultaneous determination of one pair of synthetic colorants commonly found mixed in food products, Amaranth (AM) and Tartrazine (TZ), based on their adsorption and oxidation on a screen-printed electrode (SPE) is presented. The variation of peak current with pH, supporting electrolyte, adsorption time, and adsorption potential were optimized using square wave adsorptive voltammetry. The optimal conditions were found to be: pH 3.2 (PBS), E ads 0.00 V, and t ads 30 s. Under these conditions, the AM and TZ signals were observed at 0.56 and 0.74 V, respectively. A linear response were found over the 0.15 to 1.20 µmol L -1 and 0.15 to 0.80 µmol L -1 concentrations, with detection limits (3σ/slope) of 26 and 70 nmol L -1 for AM and TZ, respectively. Reproducibility for 17.7 µmol L -1 AM and TZ solutions were 2.5 and 3.0% ( n = 7), respectively, using three different electrodes. The method was validated by determining AM and TZ in spiked tap water and unflavored gelatin spiked with AM and TZ. Because a beverage containing both AM and TZ was not found, the method was applied to the determination of AM in a kola soft drink and TZ in an orange jelly and a soft drink powder.

  13. INVESTIGATION OF AMMONIA ADSORPTION ON FLY ASH DUE TO INSTALLATION OF SELECTIVE CATALYTIC REDUCTION SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    G.F. Brendel; J.E. Bonetti; R.F. Rathbone; R.N. Frey Jr.

    2000-11-01

    This report summarizes an investigation of the potential impacts associated with the utilization of selective catalytic reduction (SCR) systems at coal-fired power plants. The study was sponsored by the U.S. Department of Energy Emission Control By-Products Consortium, Dominion Generation, the University of Kentucky Center for Applied Energy Research and GAI Consultants, Inc. SCR systems are effective in reducing nitrogen oxides (NOx) emissions as required by the Clean Air Act (CAA) Amendments. However, there may be potential consequences associated with ammonia contamination of stack emissions and combustion by-products from these systems. Costs for air quality, landfill and pond environmental compliance may increase significantly and the marketability of ash may be seriously reduced, which, in turn, may also lead to increased disposal costs. The potential impacts to air, surface water, groundwater, ash disposal, ash utilization, health and safety, and environmental compliance can not be easily quantified based on the information presently available. The investigation included: (1) a review of information and data available from published and unpublished sources; (2) baseline ash characterization testing of ash samples produced from several central Appalachian high-volatile bituminous coals from plants that do not currently employ SCR systems in order to characterize the ash prior to ammonia exposure; (3) an investigation of ammonia release from fly ash, including leaching and thermal studies; and (4) an evaluation of the potential impacts on plant equipment, air quality, water quality, ash disposal operations, and ash marketing.

  14. Substantial Humic Acid Adsorption to Activated Carbon Air Cathodes Produces a Small Reduction in Catalytic Activity.

    Science.gov (United States)

    Yang, Wulin; Watson, Valerie J; Logan, Bruce E

    2016-08-16

    Long-term operation of microbial fuel cells (MFCs) can result in substantial degradation of activated carbon (AC) air-cathode performance. To examine a possible role in fouling from organic matter in water, cathodes were exposed to high concentrations of humic acids (HA). Cathodes treated with 100 mg L(-1) HA exhibited no significant change in performance. Exposure to 1000 mg L(-1) HA decreased the maximum power density by 14% (from 1310 ± 30 mW m(-2) to 1130 ± 30 mW m(-2)). Pore blocking was the main mechanism as the total surface area of the AC decreased by 12%. Minimization of external mass transfer resistances using a rotating disk electrode exhibited only a 5% reduction in current, indicating about half the impact of HA adsorption was associated with external mass transfer resistance and the remainder was due to internal resistances. Rinsing the cathodes with deionized water did not restore cathode performance. These results demonstrated that HA could contribute to cathode fouling, but the extent of power reduction was relatively small in comparison to large mass of humics adsorbed. Other factors, such as biopolymer attachment, or salt precipitation, are therefore likely more important contributors to long-term fouling of MFC cathodes.

  15. Adsorption

    Directory of Open Access Journals (Sweden)

    Sushmita Banerjee

    2017-05-01

    Full Text Available Application of saw dust for the removal of an anionic dye, tartrazine, from aqueous solutions has been investigated. The experiments were carried out in batch mode. Effect of the parameters such as pH, initial dye concentration and temperature on the removal of the dye was studied. Equilibrium was achieved in 70 min. Maximum adsorption of dye was achieved at pH 3. Removal percent was found to be dependent on the initial concentration of dye solution, and maximum removal was found to be 97% at 1 mg/L of tartrazine. The removal increases from 71% to 97% when the initial concentration of dye solution decreases from 15 mg/L to 1 mg/L. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The (Langmuir adsorption capacity of the adsorbent is found to be 4.71 mg/g at 318 K. Kinetic modeling of the process of removal was carried out and the process of removal was found to follow a pseudo second order model and the value of rate constant for adsorption process was calculated as 2.7 × 10−3 g mg−1 min−1 at 318 K. The thermodynamic parameters such as change in free energy (ΔG°, enthalpy (ΔH° and entropy (ΔS° were determined and the negative values of ΔG° indicated that the process of removal was spontaneous at all values of temperatures. Further, the values of ΔH° indicated the endothermic nature of the process of removal.

  16. Behaviour and quantification studies of terbacil and lenacil in environmental samples using cyclic and adsorptive stripping voltammetry at hanging mercury drop electrode.

    Science.gov (United States)

    Thriveni, T; Rajesh Kumar, J; Sujatha, D; Sreedhar, N Y

    2007-05-01

    The cyclic voltammograms of terbacil and lenacil at the hanging mercury drop electrode showed a single well defined four electron irreversible peak in universal buffer of pH 4.0 for both compounds. The peak potentials were shifted to more negative values on the increase of pH of the medium, implying the involvement of protons in the electrode reaction and that the proton transfer reaction precedes the proper electrode process. The four electron single peak may be attributed to the simultaneous reduction of carbonyl groups present in 2 and 4 in pyrimidine ring of terbacil and lenacil to the corresponding hydroxy derivative. Based on the interfacial adsorptive character of the terbacil and lenacil onto the mercury electrode surface, a simple sensitive and low cost differential pulse adsorptive stripping voltammetric procedure was optimized for the analysis of terbacil and lenacil. The optimal operational conditions of the proposed procedure were accumulation potential E (acc) = -0.4 V, accumulation time t (acc) = 80 s, scan rate = 40 mV s(-1), pulse amplitude = 25 mV using a universal buffer pH 4.0 as a supporting electrolyte. The linear concentration range was found to be 1.5 x 10(-5) to 1.2 x 10(-9) mol/l and 1.5 x 10(-5) to 2.5 x 10(-8) mol/l with the lower detection limit of 1.22 x 10(-9) and 2.0 x 10(-8) mol/l. The correlation coefficient and relative standard deviation values are found to be 0.942, 0.996, 1.64% and 1.23%, respectively, for 10 replicants. The procedure was successfully applied for determination of terbacil and lenacil in formulations, mixed formulations, environmental samples such as fruit samples and spiked water samples.

  17. Direct determination of tellurium and its redox speciation at the low nanogram level in natural waters by catalytic cathodic stripping voltammetry.

    Science.gov (United States)

    Biver, Marc; Quentel, François; Filella, Montserrat

    2015-11-01

    Tellurium is one of the elements recently identified as technologically critical and is becoming a new emergent contaminant. No reliable method exists for its determination in environmental samples such as natural waters. This gap is filled by the method described here; it allows the rapid detection of trace concentrations of Te(IV) and Te(VI) in surface waters by differential pulse cathodic stripping voltammetry. It is based on the proton reduction catalysed by the absorption of Te(IV) on the mercury electrode. Under our conditions (0.1 mol L(-1) HCl) a detection limit of about 5 ng L(-1) for a deposition time of 300 s is achieved. Organic matter does not represent a problem at low concentrations; higher concentrations are eliminated by adsorptive purification. Tellurium occurs primarily as Te(IV) and Te(VI) in natural waters. Thus, determining total Te requires the reduction of Te(VI) that it is not electroactive. A number of reduction procedures have been carefully evaluated and a method based on the addition of TiCl3 to the acidified samples has been proven to reduce Te(VI) at the trace level to Te(IV) reliably and quantitatively. Therefore, the procedure described allows the direct determination of total Te and its redox speciation. It is flexible, reliable and cost effective compared to any possible alternative method based on the common preconcentration-ICPMS approach. It is readily implementable as a routine method and can be deployed in the field with relative ease. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Cathodic adsorptive stripping voltammetry of an anti-emetic agent Granisetron in pharmaceutical formulation and biological matrix

    Directory of Open Access Journals (Sweden)

    Rajeev Jain

    2012-12-01

    Full Text Available Granisetron showed one well-defined reduction peak at Hanging Mercury Drop Electrode (HMDE in the potential range from −1.3 to −1.5 V due to reduction of C=N bond. Solid-phase extraction technique was employed for extraction of Granisetron from spiked human plasma. Granisetron showed peak current enhancement of 4.45% at square-wave voltammetry and 5.33% at cyclic voltammetry as compared with the non stripping techniques. The proposed voltammetric method allowed quantification of Granisetron in pharmaceutical formulation over the target concentration range of 50–200 ng/mL with detection limit 13.63 ng/mL, whereas in human plasma 50–225 ng/mL with detection limit 11.75 ng/mL. Keywords: Granisetron, Human plasma, Solid-phase extraction, Pharmaceutical formulation, Voltammetry, Hanging mercury drop electrode

  19. Differential pulse adsorptive stripping voltammetric determination of nanomolar levels of atorvastatin calcium in pharmaceutical and biological samples using a vertically aligned carbon nanotube/graphene oxide electrode.

    Science.gov (United States)

    Silva, Tiago Almeida; Zanin, Hudson; Vicentini, Fernando Campanhã; Corat, Evaldo José; Fatibello-Filho, Orlando

    2014-06-07

    A novel vertically aligned carbon nanotube/graphene oxide (VACNT-GO) electrode is proposed, and its ability to determine atorvastatin calcium (ATOR) in pharmaceutical and biological samples by differential pulse adsorptive stripping voltammetry (DPAdSV) is evaluated. VACNT films were prepared on a Ti substrate by a microwave plasma chemical vapour deposition method and then treated with oxygen plasma to produce the VACNT-GO electrode. The oxygen plasma treatment exfoliates the carbon nanotube tips exposing graphene foils and inserting oxygen functional groups, these effects improved the VACNT wettability (super-hydrophobic) which is crucial for its electrochemical application. The electrochemical behaviour of ATOR on the VACNT-GO electrode was studied by cyclic voltammetry, which showed that it underwent an irreversible oxidation process at a potential of +1.08 V in pHcond 2.0 (0.2 mol L(-1) buffer phosphate solution). By applying DPAdSV under optimized experimental conditions the analytical curve was found to be linear in the ATOR concentration range of 90 to 3.81 × 10(3) nmol L(-1) with a limit of detection of 9.4 nmol L(-1). The proposed DPAdSV method was successfully applied in the determination of ATOR in pharmaceutical and biological samples, and the results were in close agreement with those obtained by a comparative spectrophotometric method at a confidence level of 95%.

  20. Simultaneous detection of Ponceat 4R and tartrazine in food using adsorptive stripping voltammetry on an acetylene black nanoparticle-modified electrode.

    Science.gov (United States)

    Yang, Xiaofeng; Qin, Haibin; Gao, Miaomiao; Zhang, Huajie

    2011-12-01

    Ponceau 4R and tartrazine have been widely used in foodstuffs. However, they are pathogenic if they are excessively consumed. Therefore, the detection of Ponceat 4R and tartrazine is quite important. A sensitive and rapid electrochemical method was developed for the simultaneous detection of Ponceat 4R and tartrazine using anodic adsorptive stripping voltammetry and based on the strong enhancement effect of acetylene black nanoparticle. For Ponceat 4R, the linear range was from 0.05 to 4 mg kg(-1) , and the limit of detection was 0.03 mg kg(-1) . For tartrazine, the linear range was from 0.15 to 18 mg kg(-1) , and the limit of detection was 0.1 mg kg(-1) . The relative standard deviation was 3.8% and 4.7% for 10 successive measurements of 1 mg kg(-1) Ponceau 4R and tartrazine. The method was used to determine Ponceat 4R and tartrazine in soft drinks, and recovery was in the range of 92.4-104.8%. At the acetylene black nanoparticle-modified electrode, the oxidation current signal of Ponceau 4R and tartrazine greatly increase. This new method is sensitive, rapid, simple and feasible. Copyright © 2011 Society of Chemical Industry.

  1. Electrochemical behavior of the antituberculosis drug isoniazid and its square-wave adsorptive stripping voltammetric estimation in bulk form, tablets and biological fluids at a mercury electrode.

    Science.gov (United States)

    Ghoneim, M M; el-Baradie, K Y; Tawfik, A

    2003-11-24

    Isoniazid, pyridine-4-carboxylic acid hydrazide, is an antituberculosis-agent, which is used to prevent the development of clinical tuberculosis. A validated square-wave adsorptive cathodic stripping voltammetric procedure for the trace determination of the bulk drug at the hanging mercury drop electrode (HMDE) has been developed. Under the optimized conditions, (accumulation potential=-0.9 V, accumulation time=50-300 s, scan increment=8 mV, pulse-amplitude=25 mV, frequency=120 Hz and acetate buffer at pH 5.5) isoniazed generated two irreversible cathodic peaks. The first peak current showed a linear dependence with the drug concentration over the range 5 x 10(-10)-21 x 0(-6) M. The mean percentage recoveries, based on the average of five replicate measurements, for 7 x 10(-9) and 5 x 10(-8) M isoniazid were 97.71+/-2.93 and 99.76+/-0.77, respectively. The achieved limits of detection (LOD) and quantitation (LOQ) were 1.18 x 10(-10) and 3.93 x 10(-10) M isoniazid, respectively. The procedure was applied to the assay of the drug in tablets (Isocid and T.B. Zide), spiked human serum and urine with mean percentage recoveries of 97.81+/-1.49, 97.45+/-2.09, and 97.08+/-1.06, respectively. The limits of detection of 1.47 x 10(-9) and 2.4 x 10(-8) M, and quantitation of 4.9 x 10(-9) and 8 x 10(-8) M drug in human serum and urine, respectively, were achieved. The mean values of the various pharmackinetic parameters of isoniazid (C(max), T(max), t(1/2), AUC, and K(e)), estimated from analysis of plasma of two volunteers by means of the proposed procedure were similar to literature values.

  2. Impact of geo-chemical environment of subsurface water on the measurement of ultra trace level of uranium in ground water by adsorptive stripping voltammetry

    International Nuclear Information System (INIS)

    Singhal, R.K.; Preetha, J.; Karpe, Rupali; Ajay Kumar; Hegde, A.G.

    2005-01-01

    During the present work, impacts of cations (Ca 2+ , Mg 2+ , K + ,), anions (Cl -1 , F -1 , and PO 4 3- ) and DOC (Dissolved Organic Carbon) on the measurement of ultra trace level of uranium (VI) in subsurface water by adsorptive stripping voltammetry (AdSV) is studied. The concentrations of these anions, cations and DOC in subsurface water changes due to change in the geo-chemical environment at different locations. In AdSV, concentration of U was determined by forming an uranium-chloranilic acid complex (2,5-dichloro- 3,6-dihydroxy-1,4-benzoquinone). AdSV measurements were carried out in the differential pulse (DP) mode using a pulse amplitude of -50 mV, a pulse time of 30 ms and a potential step of 4 mV. The detection limit, was calculated to 2+ , Mg 2+ , K + ) and anions (Cl -1 , F -1 , and PO 4 3- ) was carried out by using Ion Chromatography. Ground water samples were spiked with varying degree of cations, anions and DOC (dissolved organic carbon). DOC in ground waters were measured by Total Organic Carbon (TOC) analyzer. Various experiments show that analysis of uranium in the concentration range of 2+ , Mg 2+ , K + , Cl -1 , F -1 , and PO 4 3- . In case of DOC there is no interference observed in the concentration range of 0.02-15 ppm but beyond 15 ppm the concentration of uranium decrease sharply. Further, if DOC exceeded 16 ppm it was not possible to do the analysis of uranium by AdSV without destruction of DOC, as DOC is surface active organic compound and accumulates on Hg electrode preferentially over uranium-chloroanailic complex. (author)

  3. Novel acyclonucleoside analog bearing a 1,2,4-triazole–Schiff base: Synthesis, characterization and analytical studies using square wave-adsorptive stripping voltammetry and HPLC

    Directory of Open Access Journals (Sweden)

    Ali F. Alghamdi

    2017-09-01

    Full Text Available New acyclonucleoside analogs tethered by a 1,2,4-triazole scaffold were synthesized through the condensation of 4-amino-5-(2-phenyleth-1-yl-2,4-dihydro-3H-1,2,4-triazole-3-thione (2 with benzaldehyde followed by the alkylation of the resulting Schiff base (3with 2-bromoethanol, 3-chloropropanol and/or 3-chloropropan-1,2-diol. Voltammetric studies were carried out for the analysis of 1 × 10−6 mol L−1 of the newly synthesized acyclonucleoside analogs (4–6 using square wave-adsorptive stripping voltammetry (SW-AdSV. The sharp voltammetric peak and high reduction current were recorded using a Britton–Robinson B–R pH 10 buffer at Ep = −1250 mV on the hanging mercury drop surface (HMDE and Ag/AgCl reference electrode. Several experimental conditions were studied, such as the supporting electrolytes, the pH, and the accumulation time, as well as the potential, the scan rate, the frequency and the step potential for 4-benzylideneamino-5-(2-phenyleth-1-yl-3-[(2,3-dihydroxyprop-1-ylthio]-1,2,4-triazole (6. The analytical performance of the voltammetric technique was investigated through the analysis of the calibration curve, the detection limit, the recovery and the stability. The voltammetric analytical applications were evaluated by the recovery of compound (6 in the urine and plasma samples. The HPLC technique was also applied for the separation of compound (6 from interference using a C-18 (5 μm column with UV detection at 254 nm.

  4. LabVIEW-based sequential-injection analysis system for the determination of trace metals by square-wave anodic and adsorptive stripping voltammetry on mercury-film electrodes.

    Science.gov (United States)

    Economou, Anastasios; Voulgaropoulos, Anastasios

    2003-01-01

    The development of a dedicated automated sequential-injection analysis apparatus for anodic stripping voltammetry (ASV) and adsorptive stripping voltammetry (AdSV) is reported. The instrument comprised a peristaltic pump, a multiposition selector valve and a home-made potentiostat and used a mercury-film electrode as the working electrodes in a thin-layer electrochemical detector. Programming of the experimental sequence was performed in LabVIEW 5.1. The sequence of operations included formation of the mercury film, electrolytic or adsorptive accumulation of the analyte on the electrode surface, recording of the voltammetric current-potential response, and cleaning of the electrode. The stripping step was carried out by applying a square-wave (SW) potential-time excitation signal to the working electrode. The instrument allowed unattended operation since multiple-step sequences could be readily implemented through the purpose-built software. The utility of the analyser was tested for the determination of copper(II), cadmium(II), lead(II) and zinc(II) by SWASV and of nickel(II), cobalt(II) and uranium(VI) by SWAdSV.

  5. Bi-modified Pd/C catalyst via irreversible adsorption and its catalytic activity for ethanol oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Cai, Jindi; Huang, Yiyin; Guo, Yonglang

    2013-01-01

    Highlights: • Pd-Bi/C catalysts were easily prepared by irreversible adsorption of Bi on Pd/C surface. • The adsorption of Bi increases the oxygen-containing species obviously on Pd-Bi/C surface. • Only a little amount of Bi on Pd-Bi/C can play a significant role in ethanol oxidation reaction (EOR). • Current density of EOR on Pd-Bi/C (20:1) is 2.4 times higher than that on Pd/C. • Anti-poisoning ability and durability of Pd-Bi/C (20:1) is greatly enhanced. -- Abstract: A facile approach to promote ethanol electro-oxidation on Pd-based catalysts is presented by the modification of Bi on Pd/C catalyst via irreversible adsorption. X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) measurements show that the modification of Bi has no significant effect on the Pd morphology and particle size distribution. Bi(III) and Pd(0) are the dominant forms in Pd-Bi/C catalyst. Electrochemical tests show that the modification of the appropriate amount of Bi on Pd/C catalyst can remarkably enhance activity toward ethanol oxidation reaction (EOR) up to about 2.4 times higher compared to Pd/C catalyst. The Pd-Bi/C (20:1) catalyst exhibits excellent stability and enhances CO tolerance. The enhanced electrochemical performance of Pd-Bi/C catalyst is attributed to the electronic effect and the bifunctional mechanism. The high exchange current density and the low apparent activation energy on Pd-Bi/C (20:1) catalyst reveal its faster kinetics and higher intrinsic activity compared to Pd/C catalyst

  6. Zeolites - the relationship between morphostructural parameters and adsorptive/molecular sieving/catalytic properties of porous solids (models and practices)

    International Nuclear Information System (INIS)

    Hartomo, A.J.; Soendoror, N.P.C.

    1989-01-01

    Zeolites receive great attention among researchers today primarily because of their numerous industrial uses and applications, ranging from water treatment to petroleum industries, concerning adsorption, molecular sieving and/or catalysis. Some important progress taking place during the last few years - theoretical and experimental are discussed. In Indonesia, zeolites of natural origin are found in many places including the western and eastern part of Java Island. Works preparing, modifying and characterizing their performance whether by spectroscopic, thermochemical or volumetric methods are presented. Cooperation in R and D is still to be seriously and constantly increased/intensified. (Auth.). 22 refs.; 10 figs.; 2 tabs

  7. Catalytic activity in reactions of isotopic exchange of carbon monoxide and adsorption properties of catalysts on zinc oxide base

    International Nuclear Information System (INIS)

    Mikheeva, T.M.; Kasatkina, L.A.; Volynkina, A.Ya.

    1987-01-01

    Activity of different zinc oxide samples in reaction of CO homomolecular isotopic exchnge (HMIE) ( 13 C 18 O+ 12 C 16 O= 13 C 16 O+ 12 C 18 O), CO adsorption on ZnO and isotopic exchange between adsorbed and gaseous CO are investigated. The most active is ZnO sample prepared from ZnCO 3 . Quantitative ratio between different with respect to surface strength molecules of adsorbed CO are experimentally determined. It is shown that by increase of ZnO time contact with CO the quantity of adsorbed CO(N σ/0 ), capable of fast exchange with a gaseous phase, is reduced and the quantity of slowly exchanged adsorbed CO is increased. Correlation between decrease of N σ/0 and decrease of CO HMIE with the catalyst holding time in CO medium is stated

  8. Integrated Removal of NOx with Carbon Monoxide as Reductant, and Capture of Mercury in a Low Temperature Selective Catalytic and Adsorptive Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Neville Pinto; Panagiotis Smirniotis; Stephen Thiel

    2010-08-31

    Coal will likely continue to be a dominant component of power generation in the foreseeable future. This project addresses the issue of environmental compliance for two important pollutants: NO{sub x} and mercury. Integration of emission control units is in principle possible through a Low Temperature Selective Catalytic and Adsorptive Reactor (LTSCAR) in which NO{sub x} removal is achieved in a traditional SCR mode but at low temperature, and, uniquely, using carbon monoxide as a reductant. The capture of mercury is integrated into the same process unit. Such an arrangement would reduce mercury removal costs significantly, and provide improved control for the ultimate disposal of mercury. The work completed in this project demonstrates that the use of CO as a reductant in LTSCR is technically feasible using supported manganese oxide catalysts, that the simultaneous warm-gas capture of elemental and oxidized mercury is technically feasible using both nanostructured chelating adsorbents and ceria-titania-based materials, and that integrated removal of mercury and NO{sub x} is technically feasible using ceria-titania-based materials.

  9. Square-wave adsorptive stripping voltammetric determination of nanomolar levels of bezafibrate using a glassy carbon electrode modified with multi-walled carbon nanotubes within a dihexadecyl hydrogen phosphate film.

    Science.gov (United States)

    Ardila, Jorge Armando; Oliveira, Geiser Gabriel; Medeiros, Roberta Antigo; Fatibello-Filho, Orlando

    2014-04-07

    A highly sensitive method for bezafibrate determination using a glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes within a dihexadecyl hydrogen phosphate film based on square-wave adsorptive stripping voltammetry (SWAdSV) is proposed. The electrochemical behaviour of bezafibrate has been studied by cyclic voltammetry, showing an irreversible anodic peak at a potential of 1.09 V in 0.1 mol L(-1) phosphate buffer solution (pH 2.0). A study of the scan rate showed that the oxidation of bezafibrate is an adsorptive-controlled process, involving the transfer of two electrons and two protons per molecule. The analytical curve was linear over a bezafibrate concentration range from 50 to 910 nmol L(-1), with a detection limit of 16 nmol L(-1). This analytical method was successfully applied for benzafibrate determination in pharmaceutical formulations, with results showing good agreement with those obtained using a comparative spectrophotometric method, and has the potential for field application.

  10. The effect of mixed HCl–KCl competitive adsorbate on Pt adsorption and catalytic properties of Pt–Sn/Al{sub 2}O{sub 3} catalysts in propane dehydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Zangeneh, Farnaz Tahriri, E-mail: tahriri_zangeneh@yahoo.com [Department of Chemistry, Science and Research Branch, Islamic Azad University, P.O. Box 14155-4933, Tehran (Iran, Islamic Republic of); Catalyst Research Group, Petrochemical Research and Technology Company, National Petrochemical Company, P.O. Box 14358-84711, Tehran (Iran, Islamic Republic of); Taeb, Abbas [Department of Chemistry, Science and Research Branch, Islamic Azad University, P.O. Box 14155-4933, Tehran (Iran, Islamic Republic of); Gholivand, Khodayar [Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Sahebdelfar, Saeed [Catalyst Research Group, Petrochemical Research and Technology Company, National Petrochemical Company, P.O. Box 14358-84711, Tehran (Iran, Islamic Republic of)

    2015-12-01

    Highlights: • Impregnation is a critical step in preparation of Pt-based dehydrogenation catalysts. • A competitor ion could strongly influence the impregnation of Pt on alumina support. • The competitor type is much more effective than pH of impregnation solution. • HCl competitor can be partially replaced by KCl reducing acidic attack on support. • Adsorption parameters can be estimated by a simple equilibrium-based model. - Abstract: The effect of competitive adsorbate concentration and combination on the adsorption of H{sub 2}PtCl{sub 6} onto γ-Al{sub 2}O{sub 3} in the preparation and performance of PtSnK/γ-Al{sub 2}O{sub 3} catalyst for propane dehydrogenation was investigated. The catalysts were prepared by sequential impregnation of Sn and Pt precursors. The effect of competitor concentration on Pt adsorption was studied by using hydrochloric acid (0.1–0.3 M) and the effect of pH was studied by using KCl/HCl mixtures at constant (0.1 M) total chloride ion concentration. The catalysts were characterized by nitrogen adsorption/desorption, XRD, XRF, SEM and CO chemisorption. The catalytic performance tests were carried out in a fixed-bed quartz reactor under kinetic controlled condition for proper catalyst screening. It was found that the corrosive competitor HCl could be partially substituted with KCl without appreciable impact on catalyst performance with the advantage of lower acid attack on the support and reduced leaching of the deposited tin. A model based on initial concentration and uptake of the adsorbates was developed to obtain the adsorption parameters. Values of 890 μmol/g and 600 lit/mol were obtained for adsorption site concentration of the tin-impregnated support and equilibrium constant for Pt adsorption, respectively, for HCl concentration range of 0.1–0.3 M.

  11. Stripping Voltammetry

    Science.gov (United States)

    Lovrić, Milivoj

    Electrochemical stripping means the oxidative or reductive removal of atoms, ions, or compounds from an electrode surface (or from the electrode body, as in the case of liquid mercury electrodes with dissolved metals) [1-5]. In general, these atoms, ions, or compounds have been preliminarily immobilized on the surface of an inert electrode (or within it) as the result of a preconcentration step, while the products of the electrochemical stripping will dissolve in the electrolytic solution. Often the product of the electrochemical stripping is identical to the analyte before the preconcentration. However, there are exemptions to these rules. Electroanalytical stripping methods comprise two steps: first, the accumulation of a dissolved analyte onto, or in, the working electrode, and, second, the subsequent stripping of the accumulated substance by a voltammetric [3, 5], potentiometric [6, 7], or coulometric [8] technique. In stripping voltammetry, the condition is that there are two independent linear relationships: the first one between the activity of accumulated substance and the concentration of analyte in the sample, and the second between the maximum stripping current and the accumulated substance activity. Hence, a cumulative linear relationship between the maximum response and the analyte concentration exists. However, the electrode capacity for the analyte accumulation is limited and the condition of linearity is satisfied only well below the electrode saturation. For this reason, stripping voltammetry is used mainly in trace analysis. The limit of detection depends on the factor of proportionality between the activity of the accumulated substance and the bulk concentration of the analyte. This factor is a constant in the case of a chemical accumulation, but for electrochemical accumulation it depends on the electrode potential. The factor of proportionality between the maximum stripping current and the analyte concentration is rarely known exactly. In fact

  12. A solid paraffin-based carbon paste electrode modified with 2-aminothiazole organofunctionalized silica for differential pulse adsorptive stripping analysis of nickel in ethanol fuel

    International Nuclear Information System (INIS)

    Takeuchi, Regina M.; Santos, Andre L.; Padilha, Pedro M.; Stradiotto, Nelson R.

    2007-01-01

    A solid paraffin-based carbon paste electrode modified with 2-aminothiazole organofunctionalized silica (SiAt-SPCPE) was applied to Ni 2+ determination in commercial ethanol fuel samples. The proposed method comprised four steps: (1) Ni 2+ preconcentration at open circuit potential directly in the ethanol fuel sample, (2) transference of the electrode to an electrochemical cell containing DMG, (3) differential pulse voltammogram registering and (4) surface regeneration by polishing the electrode. The proposed method combines the high Ni 2+ adsorption capacity presented by 2-aminothiazole organofunctionalized silica with the electrochemical properties of the Ni(DMG) 2 complex, whose electrochemical reduction provides the analytical signal. All experimental parameters involved in the proposed method were optimized. Using a preconcentration time of 20 min, it was obtained a linear range from 7.5 x 10 -9 to 1.0 x 10 -6 mol L -1 with detection limit of 2.0 x 10 -9 mol L -1 . Recovery values between 96.5 and 102.4% were obtained for commercial samples spiked with 1.0 μmol L -1 Ni 2+ and the developed electrode was totally stable in ethanolic solutions. The contents of Ni 2+ found in the commercial samples using the proposed method were compared to those obtained by graphite furnace atomic absorption spectroscopy by using the F- and t-test. Neither the F- nor t-values exceeded the critical values at 95% confidence level, confirming that there are not statistical differences between the results obtained by both methods. These results indicate that the developed electrode can be successfully employed to reliable Ni 2+ determination in commercial ethanol fuel samples without any sample pretreatment or dilution step

  13. Thin layer chitosan-coated cellulose filter paper as substrate for immobilization of catalytic cobalt nanoparticles.

    Science.gov (United States)

    Kamal, Tahseen; Khan, Sher Bahadar; Haider, Sajjad; Alghamdi, Yousef Gamaan; Asiri, Abdullah M

    2017-11-01

    A facile approach utilizing synthesis of cobalt nanoparticles in green polymers of chitosan (CS) coating layer on high surface area cellulose microfibers of filter paper (CFP) is described for the catalytic reduction of nitrophenol and an organic dye using NaBH 4 . Simple steps of CFP coating with 1wt% CS aqueous solution followed by Co 2+ ions adsorption from 0.2M CoCl 2 aqueous solution were carried out to prepare pre-catalytic strips. The Co 2+ loaded pre-catalytic strips of CS-CFP were treated with 0.19M NaBH 4 aqueous solution to convert the ions into nanoparticles. Successful Co nanoparticles formation was assessed by various characterization techniques of FESEM, EDX and XRD analyzes. TGA analyses were carried out on CFP, CS-CFP, and Co-CS-CFP for the determination of the amount of Co particles formed on the CS-FP, and to track their thermal properties. Furthermore, we demonstrated that the Co-CS-CFP showed an excellent catalytic activity and reusability in the reduction reactions a nitroaromatic compound of 2,6-dintirophenol (2,6-DNP) and brilliant cresyl blue (BCB) dye by NaBH 4 . The Co-CS-CFP catalyzed the reduction reactions of 2,6-DNP and BCB by NaBH 4 with psuedo-first order rate constants of 0.0451 and 0.1987min -1 , respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Adsorptive Cathodic Stripping Voltammetric Determination of ...

    African Journals Online (AJOL)

    International Pharmaceutical Abstract, Chemical Abstracts, Embase, Index Copernicus, EBSCO, African. Index Medicus ... The bioavailable salt forms of ciprofloxacin in the market are ... A standard stock solution of 500 ... CyberScan pH 510 (Eutech Instruments Pte Ltd., .... variation (5%) of the most important variables i.e..

  15. Adsorptive Cathodic Stripping Voltammetric Determination of ...

    African Journals Online (AJOL)

    in spiked human urine with no matrix effect (i.e. LLOQ 0.01 μg/ml, precision (RSD < 15%) and accuracy. (85 – 115%)) ... use in quality control and pharmacokinetics studies. ... subsequently approved by US Food and Drug ... high performance liquid chromatography (HPLC) ... factors, the optimizer function of Modde software.

  16. Adsorptive Cathodic Stripping Voltammetric Determination of ...

    African Journals Online (AJOL)

    Department of Analytical Chemistry and Toxicology, Hanoi University of Pharmacy, 13-15 Le .... factors, the optimizer function of Modde software ... implementing this experiment design, other ... influence of the interaction of buffer pH with.

  17. Varicose vein stripping

    Science.gov (United States)

    ... stripping; Venous reflux - vein stripping; Venous ulcer - veins Patient Instructions Surgical wound care - open Varicose veins - what to ask your doctor Images Circulatory system References American Family Physician. Management of varicose veins. www.aafp.org/afp/2008/ ...

  18. Development physicochemical and catalytic characteristics of Mo-containing catalysts for hydrotreatment based on various supports. 1. Adsorption of molybdate anions on the support surface

    International Nuclear Information System (INIS)

    Lur'e, M.A.; Kurest, I.Z.; Krasnopol'skaya, S.M.; Reznikov, S.A.; Babikov, A.F.; Shmidt, F.K.

    1994-01-01

    The amounts of basic OH-groups were determined by means of exchange by F-ions and the adsorption of Mo from acid and alkali ammonium paramolybdate (APM) solutions was investigated on the surface of hydrated titanium dioxide, γ-Al 2 O 3 and palygorskite-montmorillonite clay. The process is adequately described by the exchange equation at pH value of APM solution in excess of the isoelectric point (IEP) of the surface. At opposite correlation between pH of the solution and IEP the Langmuir model is adaptable. They concluded, on experimental data, that in the latter case OH-groups replaced by molybdate-anion stage of synthesis of catalyst. 22 refs., 3 figs

  19. Preparation of Ag/TiO{sub 2}/SiO{sub 2} films via photo-assisted deposition and adsorptive self-assembly for catalytic bactericidal application

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Baojuan, E-mail: baojuanxi@gmail.com [Department of Electrical and Computer Engineering, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Chu, Xiaona; Hu, Jiangyong [Department of Civil and Environmental Engineering, 10 Kent Ridge Crescent, Singapore 119260 (Singapore); Bhatia, Charanjit Singh; Danner, Aaron James; Yang, Hyunsoo [Department of Electrical and Computer Engineering, 10 Kent Ridge Crescent, Singapore 119260 (Singapore)

    2014-08-30

    Highlights: • We prepared controlledly the silver nanoparticles on TiO{sub 2}/SiO{sub 2} film by the facile photoreduction under the aid of structure-directing agents. • We studied the effect of silver loading on the antibactierial behavior of TiO{sub 2} film and optimized the content of silver. • We extended the route to fabricate other metals on substrates. - Abstract: The deterioration of water supply quality due to the waterborne bacteria is an environmental problem requiring the urgent attention. Due to the excellent and synergic antimicrobial capability, Ag-loaded TiO{sub 2} photocatalyst emerges as a feasible measure to guard the water. In our work, Ag nanoparticles have been prepared by the photoassisted reduction of AgNO{sub 3} on the TiO{sub 2} film fabricated by solution-based adsorptive self-assembly approach. The role of surfactant on the growth rate and size controlling of particles is also studied. In this connection, different kinds of surfactants, such as PVP, Tween-20, Tween-40 and so on, are applied in the system to investigate the formation of Ag nanoparticles. The surface profile and elemental analysis of Ag/TiO{sub 2}/SiO{sub 2} films are examined by scanning electron microscopy and attached energy-dispersive X-ray spectroscopy, respectively. In the anti-bacteria detection, Ag nanoparticles are found to enhance the bactericidal efficiency strongly comparing with the pure TiO{sub 2} film under the same condition. In addition, by comparison with Ag/TiO{sub 2}/SiO{sub 2} film in the dark environment as the reference experiment, UV–visible light plays a vital role in the improved bactericidal behavior, demonstrating the more efficient charge separation induced by metal silver. Because of the versatility of the method, the present photoreductive route is also exploited for the synthesis of Au nanoparticles on TiO{sub 2}/SiO{sub 2} films. The corresponding photocatalytical detection results demonstrate the loading of Au nanoparticles can

  20. The Strip Module

    DEFF Research Database (Denmark)

    Pedersen, Tommy

    1996-01-01

    When the behaviour of a ship in waves is to be predicted it is convenient to have a tool which includes different approaches to the problem.The aim of this project is to develop such a tool named the strip theory module. The strip theory module will consist of submodules dependent on the I...

  1. Science Comic Strips

    Science.gov (United States)

    Kim, Dae Hyun; Jang, Hae Gwon; Shin, Dong Sun; Kim, Sun-Ja; Yoo, Chang Young; Chung, Min Suk

    2012-01-01

    Science comic strips entitled Dr. Scifun were planned to promote science jobs and studies among professionals (scientists, graduate and undergraduate students) and children. To this end, the authors collected intriguing science stories as the basis of scenarios, and drew four-cut comic strips, first on paper and subsequently as computer files.…

  2. Anatomy Comic Strips

    Science.gov (United States)

    Park, Jin Seo; Kim, Dae Hyun; Chung, Min Suk

    2011-01-01

    Comics are powerful visual messages that convey immediate visceral meaning in ways that conventional texts often cannot. This article's authors created comic strips to teach anatomy more interestingly and effectively. Four-frame comic strips were conceptualized from a set of anatomy-related humorous stories gathered from the authors' collective…

  3. The Honeycomb Strip Chamber

    International Nuclear Information System (INIS)

    Graaf, Harry van der; Buskens, Joop; Rewiersma, Paul; Koenig, Adriaan; Wijnen, Thei

    1991-06-01

    The Honeycomb Strip Chamber (HSC) is a new position sensitive detector. It consists of a stack of folded foils, forming a rigid honeycomb structure. In the centre of each hexagonal cell a wire is strung. Conducting strips on the foils, perpendicular to the wires, pick up the induced avalanche charge. Test results of a prototype show that processing the signals form three adjacent strips nearest to the track gives a spatial resolution better than 64 μm for perpendicular incident tracks. The chamber performance is only slightly affected by a magnetic field. (author). 25 refs.; 21 figs

  4. Membrane air stripping utilizing a plate and frame configuration

    International Nuclear Information System (INIS)

    Boswell, S.T.

    1991-01-01

    Membrane air stripping has recently been proposed as a possible method to remove volatile organic chemicals (VOCs) and radon from drinking water supplies. Current and anticipated regulatory requirements, driven by health consequences, make the removal of these contaminants mandatory. This work examines the use of plate and frame membrane air stripping for the removal of VOCs and radon from a water supply. The theoretical basis of membrane air stripping and a literature review are included. The advantages of membrane air stripping versus other methods of removal, as well as the advantages of a plate and frame configuration versus a hollow fiber configuration for membrane air stripping are discussed. Multiple regression/correlation techniques are used to model mass transfer coefficients and fluid resistances. An economic evaluation is performed using the developed models. The costs of comparable membrane and packed tower air stripping systems are 4.86 cents per thousand gallons versus 4.36 cents per thousand gallons, respectively. This work indicates that plate and frame membrane air stripping may, in fact, prove to be an economical alternative to packed tower aeration and carbon adsorption for the removal of VOCs and radon

  5. Cascade air stripping: Techno-economic evaluation of a new ground water treatment process

    International Nuclear Information System (INIS)

    Nirmalakhandan, N.; Peace, G.L.; Shanbhag, A.R.; Speece, R.E.

    1992-01-01

    A simple modification of the conventional air-stripping process introduced as cascade air stripping is proposed for efficient and economical removal of semivolatile and low volatility contaminants from ground water. The technical feasibility and economic viability of this process are evaluated using field test results and cost model simulations. The field tests enabled the process model to be verified at various water flow rates ranging from 150 gpm to 400 gpm. The field study also demonstrated the feasibility of the proposed system at a near full-scale level. Cost models were used to compare the proposed process to conventional air stripping and granular-activated carbon adsorption in removing a range of contaminants. This analysis showed that the treatment cost (cents/1,000 gal) of cascade air stripping is about 15% lower than conventional air stripping and about 40% lower than granular-activated carbon adsorption

  6. Catalytic treatment

    Energy Technology Data Exchange (ETDEWEB)

    Bindley, W T.R.

    1931-04-18

    An apparatus is described for the catalytic treatment of liquids, semi-liquids, and gases comprising a vessel into which the liquid, semi-liquid, or gas to be treated is introduced through a common inlet to a chamber within the vessel whence it passes to contact with a catalyst through radially arranged channels or passages to a common outlet chamber.

  7. micro strip gas chamber

    CERN Multimedia

    1998-01-01

    About 16 000 Micro Strip Gas Chambers like this one will be used in the CMS tracking detector. They will measure the tracks of charged particles to a hundredth of a millimetre precision in the region near the collision point where the density of particles is very high. Each chamber is filled with a gas mixture of argon and dimethyl ether. Charged particles passing through ionise the gas, knocking out electrons which are collected on the aluminium strips visible under the microscope. Such detectors are being used in radiography. They give higher resolution imaging and reduce the required dose of radiation.

  8. Selective chemical stripping

    Science.gov (United States)

    Malavallon, Olivier

    1995-04-01

    At the end of the 80's, some of the large European airlines expressed a wish for paint systems with improved strippability on their aircraft, allowing the possibility to strip down to the primer without altering it, using 'mild' chemical strippers based on methylene chloride. These improvements were initially intended to reduce costs and stripping cycle times while facilitating rapid repainting, and this without the need to change the conventionally used industrial facilities. The level of in-service performance of these paint systems was to be the same as the previous ones. Requirements related to hygiene safety and the environment were added to these initial requirements. To meet customers' expectations, Aerospatiale, within the Airbus Industry GIE, formed a work group. This group was given the task of specifying, following up the elaboration and qualifying the paint systems allowing requirements to be met, in relation with the paint suppliers and the airlines. The analysis made in this report showed the interest of transferring as far upstream as possible (to paint conception level) most of the technical constraints related to stripping. Thus, the concept retained for the paint system, allowing selective chemical stripping, is a 3-coat system with characteristics as near as possible to the previously used paints.

  9. ALICE Silicon Strip Detector

    CERN Multimedia

    Nooren, G

    2013-01-01

    The Silicon Strip Detector (SSD) constitutes the two outermost layers of the Inner Tracking System (ITS) of the ALICE Experiment. The SSD plays a crucial role in the tracking of the particles produced in the collisions connecting the tracks from the external detectors (Time Projection Chamber) to the ITS. The SSD also contributes to the particle identification through the measurement of their energy loss.

  10. Research progress of novel adsorption processes in water purification:A review

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    As an effective, efficient, and economic approach for water purification, adsorbents and adsorption processes have been widely studied and applied in different aspects for a long time. In the recent years, a lot of novel adsorption processes have been developed for enhancing the efficiency of removing the organic and inorganic contaminants from water. This article reviews some new adsorbents and advanced adsorption methods that specialize in their compositions, structures, functions, and characteristics used in water treatment. The review emphasizes adsorption/catalytic oxidation process, adsorption/catalytic reduction process, adsorption coupled with redox process, biomimetic sorbent and its sorption behaviors of POPs, and modified adsorbents and their water purification efficiency.

  11. Strip interpolation in silicon and germanium strip detectors

    International Nuclear Information System (INIS)

    Wulf, E. A.; Phlips, B. F.; Johnson, W. N.; Kurfess, J. D.; Lister, C. J.; Kondev, F.; Physics; Naval Research Lab.

    2004-01-01

    The position resolution of double-sided strip detectors is limited by the strip pitch and a reduction in strip pitch necessitates more electronics. Improved position resolution would improve the imaging capabilities of Compton telescopes and PET detectors. Digitizing the preamplifier waveform yields more information than can be extracted with regular shaping electronics. In addition to the energy, depth of interaction, and which strip was hit, the digitized preamplifier signals can locate the interaction position to less than the strip pitch of the detector by looking at induced signals in neighboring strips. This allows the position of the interaction to be interpolated in three dimensions and improve the imaging capabilities of the system. In a 2 mm thick silicon strip detector with a strip pitch of 0.891 mm, strip interpolation located the interaction of 356 keV gamma rays to 0.3 mm FWHM. In a 2 cm thick germanium detector with a strip pitch of 5 mm, strip interpolation of 356 keV gamma rays yielded a position resolution of 1.5 mm FWHM

  12. Photosensitive Strip RETHGEM

    CERN Document Server

    Peskov, Vladimir; Nappi, E.; Oliveira, R.; Paic, G.; Pietropaolo, F.; Picchi, P.

    2008-01-01

    An innovative photosensitive gaseous detector, consisting of a GEM like amplification structure with double layered electrodes (instead of commonly used metallic ones) coated with a CsI reflective photocathode, is described. In one of our latest designs, the inner electrode consists of a metallic grid and the outer one is made of resistive strips; the latter are manufactured by a screen printing technology on the top of the metallic strips grid The inner metallic grid is used for 2D position measurements whereas the resistive layer provides an efficient spark protected operation at high gains - close to the breakdown limit. Detectors with active areas of 10cm x10cm and 10cm x20cm were tested under various conditions including the operation in photosensitive gas mixtures containing ethylferrocene or TMAE vapors. The new technique could have many applications requiring robust and reliable large area detectors for UV visualization, as for example, in Cherenkov imaging devices.

  13. Development of a nondestructive testing method and facility for investigation of surface reactions appearing in damage, corrosion, adsorption and catalytic processes encountered in the heat transfer systems of nuclear power plants and the energy storage problems

    International Nuclear Information System (INIS)

    Gumhalter, G.

    1986-08-01

    Studies of corrosion, oxide layer growth, etc., necessitate the investigation of processes which take place at surfaces: adsorption and desorption. Two problems are of major importance: i) initial stages of oxidative attack, e.g. the adsorptive properties of oxygen for a given system and possible synergetic effects of coadsorbed species like CO, H 2 O, OH, H 2 , SH 2 , impurities, and ii) the influence of surface conditions (crystalography, defects, pores, impurities, segregates) on the oxidative attack. An apparatus has been developed with three surface sensitive techniques: a) quartzcrystal micro-balance as a method for measuring the kinetics of deposition of thin metal films and gas adsorption, b) diode probe for the measurement of work function change caused by gas adsorption at metallic surfaces, and c) thermal desorption spectroscopy (TDS) which gives information on adsorption/desorption properties of a system studied: activation energy, preexponential factors for desorption, coverage, precursor states, lateral interaction, etc. The system investigated was oxygen/palladium foil (polycrystalline) by means of TDS and the following conclusions have been drawn: 1. Oxygen adsorbs on Pd foil both dissociatively and nondissociatively - depending on the adsorption temperature. 2. Certain amounts of oxygen penetrates into the surface and subsurface region, giving rise to a desorption peak around 1350K. 3. There are two groups of desorption peaks corresponding to atomically adsorbed oxygen (730K and 800K). The analysis of these peaks show the existence of strong lateral interactions between oxygen atoms at high coverages, which is not the case for low coverages. The position of the peaks and the dynamics of their evolution is consistent with the data obtained for Pd(111) and Pd(100) single crystal surfaces

  14. Removal of binary dyes mixtures with opposite and similar charges by adsorption, coagulation/flocculation and catalytic oxidation in the presence of CeO2/H2O2 Fenton-like system.

    Science.gov (United States)

    Issa Hamoud, Houeida; Finqueneisel, Gisèle; Azambre, Bruno

    2017-06-15

    In this study, the removal of binary mixtures of dyes with similar (Orange II/Acid Green 25) or opposite charges (Orange II/Malachite Green) was investigated either by simple adsorption on ceria or by the heterogeneous Fenton reaction in presence of H 2 O 2 . First, the CeO 2 nanocatalyst with high specific surface area (269 m 2 /g) and small crystal size (5 nm) was characterized using XRD, Raman spectroscopy and N 2 physisorption at 77 K. The adsorption of single dyes was studied either from thermodynamic and kinetic viewpoints. It is shown that the adsorption of dyes on ceria surface is highly pH-dependent and followed a pseudo-second order kinetic model. Adsorption isotherms fit well the Langmuir model with a complete monolayer coverage and higher affinity towards Orange II at pH 3, compared to other dyes. For the (Orange II/Acid Green 25) mixture, both the amounts of dyes adsorbed on ceria surface and discoloration rates measured from Fenton experiments were decreased by comparison with single dyes. This is due to the adsorption competition existing onto the same surface Ce x+ sites and the reaction competition with hydroxyl radicals, respectively. The behavior of the (Orange II/Malachite Green) mixture is markedly different. Dyes with opposite charges undergo paired adsorption on ceria as well as homogeneous and heterogeneous coagulation/flocculation processes, but can also be removed by heterogeneous Fenton process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Study of heterogeneous catalytic processes over cobalt, molybdenum and cobalt-molybdenum catalysts supported on alumina by temperature-programmed desorption and temperature-programmed reaction. 1. Adsorption of hydrozen

    International Nuclear Information System (INIS)

    Rozanov, V.V.; Tsao Yamin; Krylov, O.V.

    1996-01-01

    Hydrogen adsorption on reduced, sulphidized and reoxidized specimens of molybdenum-and cobalt-molybdenum-containing catalysts applied on aluminium oxide has been studied by the method of thermal desorption (TD). Comparison of TD spectra of hydrogen and data of X-ray phase analysis of the specimens and mass-spectrometric analysis of the products desorbed from the surface of catalysts after their successive reduction sulphidizing, carbonizing and reoxidation permitted a correlation between various forms of hydrogen adsorption and certain centres on the surface of the catalysts. 12 refs., 2 figs

  16. Dynamic Underground Stripping Project

    International Nuclear Information System (INIS)

    Aines, R.; Newmark, R.; McConachie, W.; Udell, K.; Rice, D.; Ramirez, A.; Siegel, W.; Buettner, M.; Daily, W.; Krauter, P.; Folsom, E.; Boegel, A.J.; Bishop, D.; Udell, K.

    1992-01-01

    LLNL is collaborating with the UC Berkeley College of Engineering to develop and demonstrate a system of thermal remediation and underground imaging techniques for use in rapid cleanup of localized underground spills. Called ''Dynamic Stripping'' to reflect the rapid and controllable nature of the process, it will combine steam injection, direct electrical heating, and tomographic geophysical imaging in a cleanup of the LLNL gasoline spill. In the first 8 months of the project, a Clean Site engineering test was conducted to prove the field application of the techniques before moving the contaminated site in FY 92

  17. Catalytic Hydrogenation of CO2 to Methanol: Study of Synergistic Effect on Adsorption Properties of CO2 and H2 in CuO/ZnO/ZrO2 System

    Directory of Open Access Journals (Sweden)

    Chunjie Huang

    2015-11-01

    Full Text Available A series of CuO/ZnO/ZrO2 (CZZ catalysts with different CuO/ZnO weight ratios have been synthesized by citrate method and tested in the catalytic hydrogenation of CO2 to methanol. Experimental results showed that the catalyst with the lowest CuO/ZnO weight ratio of 2/7 exhibited the best catalytic performance with a CO2 conversion of 32.9%, 45.8% methanol selectivity, and a process delivery of 193.9 gMeOH·kgcat−1·h−1. A synergetic effect is found by systematic temperature-programmed-desorption (TPD studies. Comparing with single and di-component systems, the interaction via different components in a CZZ system provides additional active sites to adsorb more H2 and CO2 in the low temperature range, resulting in higher weight time yield (WTY of methanol.

  18. Strip casting apparatus and method

    Science.gov (United States)

    Williams, R.S.; Baker, D.F.

    1988-09-20

    Strip casting apparatus including a molten-metal-holding container and a nozzle to deposit molten metal onto a moving chill drum to directly cast continuous metallic strip. The nozzle body includes a slot bounded between a back and a front lip. The slot width exceeds about 20 times the gap distance between the nozzle and the chill drum surface. Preferably, the slot width exceeds 0.5 inch. This method of strip casting minimizes pressure drop, insuring better metal-to-chill-drum contact which promotes heat transfer and results in a better quality metallic strip. 6 figs.

  19. Adsorptive Transfer Stripping AC Voltammetry of DNA Complexes with Intercalators

    Czech Academy of Sciences Publication Activity Database

    Fojta, Miroslav; Havran, Luděk; Fulnečková, Jana; Kubičárová, Tatiana

    2000-01-01

    Roč. 12, č. 12 (2000), s. 926-934 ISSN 1040-0397 R&D Projects: GA AV ČR IAA4004801; GA ČR GA204/98/P091; GA ČR GV204/97/K084 Institutional research plan: CEZ:AV0Z5004920 Subject RIV: BO - Biophysics Impact factor: 1.972, year: 2000

  20. Highly efficient catalytic systems based on Pd-coated microbeads

    Science.gov (United States)

    Lim, Jin Hyun; Cho, Ahyoung; Lee, Seung Hwan; Park, Bumkyo; Kang, Dong Woo; Koo, Chong Min; Yu, Taekyung; Park, Bum Jun

    2018-01-01

    The efficiency of two prototype catalysis systems using palladium (Pd)-coated microparticles was investigated with regard to the recovery and recyclability of the catalytic particles. One such system was the interface-adsorption method, in which polymer particles coated with Pd nanoparticles strongly and irreversibly attach to the oil-water interface. Due to the irreversible adsorption of the catalytic particles to the interface, particle loss was completely prevented while mixing the aqueous solution and while collecting the products. The other system was based on the magnetic field-associated particle recovery method. The use of polymeric microparticles containing Pd nanoparticles and magnetite nanoparticles accelerated the sedimentation of the particles in the aqueous phase by applying a strong magnetic field, consequently suppressing drainage of the particles from the reactor along the product stream. Upon multiple runs of the catalytic reactions, it was found that conversion does not change significantly, demonstrating the excellent recyclability and performance efficiency in the catalytic processes.

  1. Effect of radioactive radiation on catalytic properties of solid materials

    Energy Technology Data Exchange (ETDEWEB)

    Sokol' skii, D V; Kuzembaev, K K; Kel' man, I V [AN Kazakhskoj SSR, Alma-Ata. Inst. Organicheskogo Kataliza i Ehlektrokhimii

    1977-05-01

    General survey is made of the problem of radiation modification of the action of solid catalysts with respect to the various types of heterogeneous catalytic reactions. Consideration is given to the key mechanisms responsible for radiation damage in the interaction of high-energy radiation with a solid body. The effect of ionizing radiation on the adsorption capacity and catalytic activity of solid bodies is discussed.

  2. Characterization of galvannealed strip

    International Nuclear Information System (INIS)

    Moreas, G.; Hardy, Y.

    1999-01-01

    With the aim of enhancing coating quality control during galvannealing process, an online microscopic image acquisition sensor has been developed at CRM. In galvannealing process, the ζ phase surface density is a coating quality characteristic, and the on-line microscope, equipped with optics placed at 20 mm from the surface, grabs 250 μm x 190 μm images on which ζ crystals (approximate dimensions: 1 μm x 10 μm) can be clearly identified. On-line, the sensor is mounted in front of a roll where the strip has a stable position. The coating surface to sensor optics distance is continuously measured by an accurate triangulation sensor (1 μm repeatability) and is adjusted in such a way that, due to roll eccentricity, the image is focused at least twice per revolution. When focused, image of moving product is frozen by a short (10 ns) laser light pulse and is grabbed. The obtained image is then processed to extract ζ phase percentage and allows adjustment of process parameters to reach the desired coating characteristics. (author)

  3. Air Stripping Designs and Reactive Water Purification Processes for the Lunar Surface

    Science.gov (United States)

    Boul, Peter J.; Lange, Kevin; Conger, Bruce; Anderson, Molly

    2010-01-01

    Air stripping designs are considered to reduce the presence of volatile organic compounds in the purified water. Components of the wastewater streams are ranked by Henry's Law Constant and the suitability of air stripping in the purification of wastewater in terms of component removal is evaluated. Distillation processes are modeled in tandem with air stripping to demonstrate the potential effectiveness and utility of these methods in recycling wastewater on the Moon. Scaling factors for distillation and air stripping columns are presented to account for the difference in the lunar gravitation environment. Commercially available distillation and air stripping units which are considered suitable for Exploration Life Support are presented. The advantages to the various designs are summarized with respect to water purity levels, power consumption, and processing rates. An evaluation of reactive distillation and air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

  4. Buffers and vegetative filter strips

    Science.gov (United States)

    Matthew J. Helmers; Thomas M. Isenhart; Michael G. Dosskey; Seth M. Dabney

    2008-01-01

    This chapter describes the use of buffers and vegetative filter strips relative to water quality. In particular, we primarily discuss the herbaceous components of the following NRCS Conservation Practice Standards.

  5. Magnetic stripping studies for SPL

    CERN Document Server

    Posocco, P; CERN. Geneva. BE Department

    2010-01-01

    Magnetic stripping of H- can seriously enhance the beam losses along the SPL machine. These losses depend on the beam energy, on the beam transverse distribution and on the intensity of the magnetic field. For radioprotection issues the losses must be limited to 1 W/m. In this paper we will concentrate on the stripping phenomena inside the quadrupole magnets with the aim of defining the quadrupole range for the design phase of SPL.

  6. Thermal Adsorption Processing Of Hydrocarbon Residues

    Directory of Open Access Journals (Sweden)

    Sudad H. Al.

    2017-04-01

    Full Text Available The raw materials of secondary catalytic processes must be pre-refined. Among these refining processes are the deasphalting and demetallization including their thermo adsorption or thermo-contact adsorption variety. In oil processing four main processes of thermo-adsorption refining of hydrocarbon residues are used ART Asphalt Residual Treating - residues deasphaltizing 3D Discriminatory Destructive Distillation developed in the US ACT Adsorption-Contact Treatment and ETCC Express Thermo-Contact Cracking developed in Russia. ART and ACT are processes with absorbers of lift type reactor while 3D and ETCC processes are with an adsorbing reactor having ultra-short contact time of the raw material with the adsorbent. In all these processes refining of hydrocarbon residues is achieved by partial Thermo-destructive transformations of hydrocarbons and hetero-atomic compounds with simultaneous adsorption of the formed on the surface of the adsorbents resins asphaltene and carboids as well as metal- sulphur - and nitro-organic compounds. Demetallized and deasphalted light and heavy gas oils or their mixtures are a quality raw material for secondary deepening refining processes catalytic and hydrogenation cracking etc. since they are characterized by low coking ability and low content of organometallic compounds that lead to irreversible deactivation of the catalysts of these deepening processes.

  7. Reversibility of substrate adsorption for the cellulases Cel7A, Cel6A and Cel7B from H. jecorina

    DEFF Research Database (Denmark)

    Pellegrini, Vanessa de Oliveira Arnoldi; Lei, Nina; Kysaram, Madhuri

    2014-01-01

    Adsorption of cellulases on the cellulose surface is an integral part of the catalytic mechanism, and a detailed description of the adsorption process is therefore required for a fundamental understanding of this industrially important class of enzymes. However, the mode of adsorption has proven...

  8. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

    International Nuclear Information System (INIS)

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-01-01

    Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane

  9. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Sangchul; Namkoong, Wan [Department of Environmental Engineering, Konkuk University, Hwayang-Dong, Gwangjin-Gu, Seoul 143-701 (Korea, Republic of); Kang, Jeong-Hee; Park, Jin-Kyu [Department of Environmental Engineering, Anyang University, Anyang 5-Dong, Manan-Gu, Anyang-Si, Gyeonggi-Do 430-714 (Korea, Republic of); Lee, Namhoon, E-mail: nhlee@anyang.ac.kr [Department of Environmental Engineering, Anyang University, Anyang 5-Dong, Manan-Gu, Anyang-Si, Gyeonggi-Do 430-714 (Korea, Republic of)

    2013-10-15

    Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

  10. Fundamental study of manganese dioxide for catalytic recombustion of exhaust gas of motor car

    Energy Technology Data Exchange (ETDEWEB)

    Shimoyamada, T

    1974-01-01

    The catalytic activities of five manganese dioxide preparations were tested in a pulse reactor to assess their carbon monoxide-oxidizing capability in relation to the catalytic afterburning of automobile exhaust gases. Catalysts prepared from manganese sulfate showed diminished catalytic activity as a result of sulfate poisoning. Higher oxidation activity was obtained with a catalyst prepared by precipitating the permanganate salt in acidic solution. Two forms of carbon monoxide adsorption were demonstrated, each with a characteristic activation energy and reaction temperature.

  11. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.

    Science.gov (United States)

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-10-01

    Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Magnetic ring for stripping enhancement

    International Nuclear Information System (INIS)

    Selph, F.

    1992-10-01

    A ring designed to recycle ions through a stripping medium offers the possibility for increasing output of the desired charge state by up to 4x. This could be a very important component of a Radioactive Nuclear Beam Facility. In order for such a ring to work effectively it must satisfy certain design conditions. These include achromaticity at the stripper, a dispersed region for an extraction magnet, and a number of first and higher order optics constraints which are necessary to insure that the beam emittance is not degraded unduly by the ring. An example is given of a candidate design of a stripping ring

  13. Enhancement of the catalytic activity of Pt nanoparticles toward methanol electro-oxidation using doped-SnO2 supporting materials

    Science.gov (United States)

    Merati, Zohreh; Basiri Parsa, Jalal

    2018-03-01

    Catalyst supports play important role in governing overall catalyst activity and durability. In this study metal oxides (SnO2, Sb and Nb doped SnO2) were electrochemically deposited on titanium substrate (Ti) as a new support material for Pt catalyst in order to electro-oxidation of methanol. Afterward platinum nanoparticles were deposited on metal oxide film via electro reduction of platinum salt in an acidic solution. The surface morphology of modified electrodes were evaluated by field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDX) techniques. The electro-catalytic activities of prepared electrodes for methanol oxidation reaction (MOR) and oxidation of carbon monoxide (CO) absorbed on Pt was considered with cyclic voltammetry. The results showed high catalytic activity for Pt/Nb-SnO2/Ti electrode. The electrochemical surface area (ECSA) of a platinum electro-catalyst was determined by hydrogen adsorption. Pt/Nb-SnO2/Ti electrode has highest ECSA compared to other electrode resulting in high activity toward methanol electro-oxidation and CO stripping experiments. The doping of SnO2 with Sb and Nb improved ECSA and MOR activity, which act as electronic donors to increase electronic conductivity.

  14. Activated Carbon Preparation and Modification for Adsorption

    Science.gov (United States)

    Cao, Yuhe

    Butanol is considered a promising, infrastructure-compatible biofuel. Butanol has a higher energy content than ethanol and can be used in conventional gas engines without modifications. Unfortunately, the fermentation pathway for butanol production is restricted by its toxicity to the microbial strains used in the process. Butanol is toxic to the microbes, and this can slow fermentation rates and reduce butanol yields. Gas stripping technology can efficiently remove butanol from the fermentation broth as it is produced, thereby decreasing its inhibitory effects. Traditional butanol separation heavily depends on the energy intensive distillation method. One of the main issues in acetone-butanol-ethanol fermentation is that butanol concentrations in the fermentation broth are low, ranging from 1 to 1.2 percent in weight, because of its toxicity to the microorganisms. Therefore distillation of butanol is even worse than distillation of corn ethanol. Even new separation methods, such as solid- extraction methods involve adding substances, such as polymer resin and zeolite or activated carbon, to biobutanol fermentatioon broth did not achieve energy efficient separation of butanol due to low adsorption selectivity and fouling in broth. Gas-stripping - condensation is another new butanol recovery method, however, the butanol in gas-stripping stream is too low to be condensed without using expensive and energy intensive liquid nitrogen. Adsorption can then be used to recover butanol from the vapor phase. Activated carbon (AC) samples and zeolite were investigated for their butanol vapor adsorption capacities. Commercial activated carbon was modified via hydrothermal H2O2 treatment, and the specific surface area and oxygen-containing functional groups of activated carbon were tested before and after treatment. Hydrothermal H2O 2 modification increased the surface oxygen content, Brunauer-Emmett-Teller surface area, micropore volume, and total pore volume of active carbon

  15. Using Comic Strips in Language Classes

    Science.gov (United States)

    Csabay, Noémi

    2006-01-01

    The author believes that using comic strips in language-learning classes has three main benefits. First, comic strips motivate younger learners. Second, they provide a context and logically connected sentences to help language learning. Third, their visual information is helpful for comprehension. The author argues that comic strips can be used in…

  16. Method of stripping solid particles

    International Nuclear Information System (INIS)

    1980-01-01

    A method of stripping loaded solid particles is specified in which uniform batches of the loaded particles are passed successively upwardly through an elution column in the form of discrete plugs, the particles of which do not intermingle substantially with the particles of the vertically adjacent plug(s), and are contacted therein with eluant liquid flowed downwardly, strong eluate being withdrawn from the lower region of the column, the loaded particles being supplied as a slurry in a carrier liquid, and successive batches of loaded particles being isolated as measured batches and being separated from their carrier liquid before being contacted with strong eluate and slurried with the strong eluate into the lower region of the column. An example describes the stripping of ion exchange resin particles loaded with complex uranium ions. (author)

  17. Henna wood as an adsorptive material for bentazon

    African Journals Online (AJOL)

    SAM

    2014-08-27

    Aug 27, 2014 ... removal of impurities from liquids and gases (Chowdhury ... terrestrial non-food crops: ornamental lawns and turf. It ... Carbonization was carried out in a vertical stainless-steel reactor ..... an essential procedure before designing the adsorption ..... Catalytic processes for the purification of drinking water.

  18. Collisional stripping of planetary crusts

    Science.gov (United States)

    Carter, Philip J.; Leinhardt, Zoë M.; Elliott, Tim; Stewart, Sarah T.; Walter, Michael J.

    2018-02-01

    Geochemical studies of planetary accretion and evolution have invoked various degrees of collisional erosion to explain differences in bulk composition between planets and chondrites. Here we undertake a full, dynamical evaluation of 'crustal stripping' during accretion and its key geochemical consequences. Crusts are expected to contain a significant fraction of planetary budgets of incompatible elements, which include the major heat producing nuclides. We present smoothed particle hydrodynamics simulations of collisions between differentiated rocky planetesimals and planetary embryos. We find that the crust is preferentially lost relative to the mantle during impacts, and we have developed a scaling law based on these simulations that approximates the mass of crust that remains in the largest remnant. Using this scaling law and a recent set of N-body simulations of terrestrial planet formation, we have estimated the maximum effect of crustal stripping on incompatible element abundances during the accretion of planetary embryos. We find that on average approximately one third of the initial crust is stripped from embryos as they accrete, which leads to a reduction of ∼20% in the budgets of the heat producing elements if the stripped crust does not reaccrete. Erosion of crusts can lead to non-chondritic ratios of incompatible elements, but the magnitude of this effect depends sensitively on the details of the crust-forming melting process on the planetesimals. The Lu/Hf system is fractionated for a wide range of crustal formation scenarios. Using eucrites (the products of planetesimal silicate melting, thought to represent the crust of Vesta) as a guide to the Lu/Hf of planetesimal crust partially lost during accretion, we predict the Earth could evolve to a superchondritic 176Hf/177Hf (3-5 parts per ten thousand) at present day. Such values are in keeping with compositional estimates of the bulk Earth. Stripping of planetary crusts during accretion can lead to

  19. SHORT COMMUNICATION CATALYTIC KINETIC ...

    African Journals Online (AJOL)

    IV) catalyzes the discoloring reaction of DBS-arsenazo oxidized by potassium bromate, a new catalytic kinetic spectrophotometric method for the determination of trace titanium (IV) was developed. The linear range of the determination of ...

  20. Catalytic distillation process

    Science.gov (United States)

    Smith, L.A. Jr.

    1982-06-22

    A method is described for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C[sub 4] feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  1. Adsorption/desorption of biomacromolecules involved in catalytic hydrogen evolution

    Czech Academy of Sciences Publication Activity Database

    Strmečki, S.; Paleček, Emil

    2018-01-01

    Roč. 120, APR2018 (2018), s. 87-93 ISSN 1567-5394 R&D Projects: GA ČR(CZ) GA15-15479S Institutional support: RVO:68081707 Keywords : surface-active substances * free electrochemical analysis * mercury-electrodes Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 3.346, year: 2016

  2. Study of catalytic phenomena in radiation chemistry

    International Nuclear Information System (INIS)

    Dran, J.C.

    1965-01-01

    Two phenomena have been studied: the action of γ rays from radio-cobalt on the adsorption and catalytic properties of ZnO and NiO in. relationship with the heterogeneous oxidation of CO, and the homogeneous catalysis by OsO 4 of the oxidation of various aqueous phase solutes by the same radiation. The prior irradiation of ZnO and of NiO does not modify their catalytic activity but generally increases the adsorption energy of -the gases CO and O 2 . The influence of the radiations appears to be connected with the presence of traces of water on ZnO and of an excess of oxygen on NiO. Osmium tetroxide which is not degraded by irradiation in acid solution, accelerates the radiolytic oxidation of certain compounds (Te IV , Pt 11 , As 111 ) in the presence of oxygen, as a result of its sensitizing effect on the oxidation by H 2 O 2 . In the case of phosphites on the other hand, OsO 4 has a protecting action under certain conditions of acidity and may suppress entirely the chain reaction which characterizes the oxidation of this solute byγ rays. A general mechanism is proposed for these phenomena. The rate constant for the OsO 4 + HO 2 reaction is calculated to be 5.7 x 10 5 l.mol -1 . sec -1 . (author) [fr

  3. Catalytic distillation structure

    Science.gov (United States)

    Smith, L.A. Jr.

    1984-04-17

    Catalytic distillation structure is described for use in reaction distillation columns, and provides reaction sites and distillation structure consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and is present with the catalyst component in an amount such that the catalytic distillation structure consists of at least 10 volume % open space. 10 figs.

  4. Modeling adsorption: Investigating adsorbate and adsorbent properties

    Science.gov (United States)

    Webster, Charles Edwin

    1999-12-01

    Surface catalyzed reactions play a major role in current chemical production technology. Currently, 90% of all chemicals are produced by heterogeneously catalyzed reactions. Most of these catalyzed reactions involve adsorption, concentrating the substrate(s) (the adsorbate) on the surface of the solid (the adsorbent). Pore volumes, accessible surface areas, and the thermodynamics of adsorption are essential in the understanding of solid surface characteristics fundamental to catalyst and adsorbent screening and selection. Molecular properties such as molecular volumes and projected molecular areas are needed in order to convert moles adsorbed to surface volumes and areas. Generally, these molecular properties have been estimated from bulk properties, but many assumptions are required. As a result, different literature values are employed for these essential molecular properties. Calculated molar volumes and excluded molecular areas are determined and tabulated for a variety of molecules. Molecular dimensions of molecules are important in the understanding of molecular exclusion as well as size and shape selectivity, diffusion, and adsorbent selection. Molecular dimensions can also be used in the determination of the effective catalytic pore size of a catalyst. Adsorption isotherms, on zeolites, (crystalline mineral oxides) and amorphous solids, can be analyzed with the Multiple Equilibrium Analysis (MEA) description of adsorption. The MEA produces equilibrium constants (Ki), capacities (ni), and thermodynamic parameters (enthalpies, ΔHi, and entropies, ΔSi) of adsorption for each process. Pore volumes and accessible surface areas are calculated from the process capacities. Adsorption isotherms can also be predicted for existing and new adsorbate-adsorbent systems with the MEA. The results show that MEA has the potential of becoming a standard characterization method for microporous solids that will lead to an increased understanding of their behavior in gas

  5. 3D silicon strip detectors

    International Nuclear Information System (INIS)

    Parzefall, Ulrich; Bates, Richard; Boscardin, Maurizio; Dalla Betta, Gian-Franco; Eckert, Simon; Eklund, Lars; Fleta, Celeste; Jakobs, Karl; Kuehn, Susanne; Lozano, Manuel; Pahn, Gregor; Parkes, Chris; Pellegrini, Giulio; Pennicard, David; Piemonte, Claudio; Ronchin, Sabina; Szumlak, Tomasz; Zoboli, Andrea; Zorzi, Nicola

    2009-01-01

    While the Large Hadron Collider (LHC) at CERN has started operation in autumn 2008, plans for a luminosity upgrade to the Super-LHC (sLHC) have already been developed for several years. This projected luminosity increase by an order of magnitude gives rise to a challenging radiation environment for tracking detectors at the LHC experiments. Significant improvements in radiation hardness are required with respect to the LHC. Using a strawman layout for the new tracker of the ATLAS experiment as an example, silicon strip detectors (SSDs) with short strips of 2-3 cm length are foreseen to cover the region from 28 to 60 cm distance to the beam. These SSD will be exposed to radiation levels up to 10 15 N eq /cm 2 , which makes radiation resistance a major concern for the upgraded ATLAS tracker. Several approaches to increasing the radiation hardness of silicon detectors exist. In this article, it is proposed to combine the radiation hard 3D-design originally conceived for pixel-style applications with the benefits of the established planar technology for strip detectors by using SSDs that have regularly spaced doped columns extending into the silicon bulk under the detector strips. The first 3D SSDs to become available for testing were made in the Single Type Column (STC) design, a technological simplification of the original 3D design. With such 3D SSDs, a small number of prototype sLHC detector modules with LHC-speed front-end electronics as used in the semiconductor tracking systems of present LHC experiments were built. Modules were tested before and after irradiation to fluences of 10 15 N eq /cm 2 . The tests were performed with three systems: a highly focused IR-laser with 5μm spot size to make position-resolved scans of the charge collection efficiency, an Sr 90 β-source set-up to measure the signal levels for a minimum ionizing particle (MIP), and a beam test with 180 GeV pions at CERN. This article gives a brief overview of the results obtained with 3D-STC-modules.

  6. 3D silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Parzefall, Ulrich [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany)], E-mail: ulrich.parzefall@physik.uni-freiburg.de; Bates, Richard [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Boscardin, Maurizio [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Dalla Betta, Gian-Franco [INFN and Universita' di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Eckert, Simon [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Eklund, Lars; Fleta, Celeste [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Jakobs, Karl; Kuehn, Susanne [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Lozano, Manuel [Instituto de Microelectronica de Barcelona, IMB-CNM, CSIC, Barcelona (Spain); Pahn, Gregor [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Parkes, Chris [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Pellegrini, Giulio [Instituto de Microelectronica de Barcelona, IMB-CNM, CSIC, Barcelona (Spain); Pennicard, David [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Piemonte, Claudio; Ronchin, Sabina [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Szumlak, Tomasz [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Zoboli, Andrea [INFN and Universita' di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Zorzi, Nicola [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy)

    2009-06-01

    While the Large Hadron Collider (LHC) at CERN has started operation in autumn 2008, plans for a luminosity upgrade to the Super-LHC (sLHC) have already been developed for several years. This projected luminosity increase by an order of magnitude gives rise to a challenging radiation environment for tracking detectors at the LHC experiments. Significant improvements in radiation hardness are required with respect to the LHC. Using a strawman layout for the new tracker of the ATLAS experiment as an example, silicon strip detectors (SSDs) with short strips of 2-3 cm length are foreseen to cover the region from 28 to 60 cm distance to the beam. These SSD will be exposed to radiation levels up to 10{sup 15}N{sub eq}/cm{sup 2}, which makes radiation resistance a major concern for the upgraded ATLAS tracker. Several approaches to increasing the radiation hardness of silicon detectors exist. In this article, it is proposed to combine the radiation hard 3D-design originally conceived for pixel-style applications with the benefits of the established planar technology for strip detectors by using SSDs that have regularly spaced doped columns extending into the silicon bulk under the detector strips. The first 3D SSDs to become available for testing were made in the Single Type Column (STC) design, a technological simplification of the original 3D design. With such 3D SSDs, a small number of prototype sLHC detector modules with LHC-speed front-end electronics as used in the semiconductor tracking systems of present LHC experiments were built. Modules were tested before and after irradiation to fluences of 10{sup 15}N{sub eq}/cm{sup 2}. The tests were performed with three systems: a highly focused IR-laser with 5{mu}m spot size to make position-resolved scans of the charge collection efficiency, an Sr{sup 90}{beta}-source set-up to measure the signal levels for a minimum ionizing particle (MIP), and a beam test with 180 GeV pions at CERN. This article gives a brief overview of

  7. Dynamic Underground Stripping Demonstration Project

    International Nuclear Information System (INIS)

    Aines, R.; Newmark, R.; McConachie, W.; Rice, D.; Ramirez, A.; Siegel, W.; Buettner, M.; Daily, W.; Krauter, P.; Folsom, E.; Boegel, A.J.; Bishop, D.; udel, K.

    1992-03-01

    LLNL is collaborating with the UC Berkeley College of Engineering to develop and demonstrate a system of thermal remediation and underground imaging techniques for use in rapid cleanup of localized underground spills. Called ''Dynamic Stripping'' to reflect the rapid and controllable nature of the process, it will combine steam injection, direct electrical heating, and tomographic geophysical imaging in a cleanup of the LLNL gasoline spill. In the first 8 months of the project, a Clean Site engineering test was conducted to prove the field application of the techniques before moving to the contaminated site in FY 92

  8. Depletive stripping chronopotentiometry : a major step forward in electrochemical stripping techniques for metal ion speciation analysis

    NARCIS (Netherlands)

    Town, R.M.; Leeuwen, van H.P.

    2004-01-01

    A comparative evaluation of the utility of the various modes of stripping chronopotentiometry (SCP) for trace metal speciation analysis is presented in the broad context of stripping voltammetric techniques. The remarkable fundamental advantages of depletive SCP at scanned deposition potential

  9. Potential profile in a conducting polymer strip

    DEFF Research Database (Denmark)

    Bay, Lasse; West, Keld; Vlachopoulos, Nikolaos

    2002-01-01

    Many conjugated polymers show an appreciable difference in volume between their oxidized and reduced forms. This property can be utilized in soft electrochemically driven actuators, "artificial muscles". Several geometries have been proposed for the conversion of the volume expansion into useful...... mechanical work. In a particularly simple geometry, the length change of polymer strips is exploited. The polymer strips are connected to the driving circuit at the end of the strip that is attached to the support of the device. The other end of the strip is connected to the load. The advantage of this set...

  10. Optimizing the Stripping Procedure for LHCb

    CERN Document Server

    Richardson, Rachel

    2017-01-01

    The LHCb experiment faces a major challenge from the large amounts of data received while the LHC is running. The ability to sort this information in a useful manner is important for working groups to perform physics analyses. Both hardware and software triggers are used to decrease the data rate and then the stripping process is used to sort the data into streams and further into stripping lines. This project studies the hundreds of stripping lines to look for overlaps between them in order to make the stripping process more efficient.

  11. Study on lifetime of C stripping foils

    International Nuclear Information System (INIS)

    Zhang Hongbin; Lu Ziwei; Zhao Yongtao; Li Zhankui; Xu Hushan; Xiao Guoqing; Wang Yuyu; Zhang Ling; Li Longcai; Fang Yan

    2007-01-01

    The carbon stripping foils can be prepared with the AC and DC arc discharge methods, or even sandwiched with AC-DC alternative layers. The lifetime of the carbon stripping foils of 19 μg/cm 2 prepared with different methods and/or structures was measured. The factors affecting the bombarding lifetime of the carbon stripping foils, especially the method of the foil preparation and the structure of the carbon stripping foils, were discussed. It is observed that the foils prepared with the DC arc discharge method have a longer bombarding lifetime than those prepared with the AC arc discharge method. (authors)

  12. The Whipple Strip Sky Survey

    Science.gov (United States)

    Kertzman, M. P.

    As part of the normal operation of the Whipple 10m Gamma Ray telescope, ten minute drift scan “zenith” runs are made each night of observation for use as calibration. Most of the events recorded during a zenith run are due to the background of cosmic ray showers. However, it would be possible for a hitherto unknown source of gamma rays to drift through the field. This paper reports the results of a search for serendipitous high energy gamma ray sources in the Whipple 10m nightly calibration zenith data. From 2000-2004 nightly calibration runs were taken at an elevation of 89 º. A 2- D analysis of these drift scan runs produces a strip of width ~ 3.5º in declination and spanning the full range of right ascension. In the 2004-05 observing season the calibration runs were taken at elevations of 86° and 83°. Beginning in the 2005-06 season, the nightly calibration runs were taken at an elevation of 80º. Collectively, these drift scans cover a strip approximately 12.5º wide in declination, centered at declination 37.18º, and spanning the full range of RA. The analysis procedures developed for drift scan data, the sensitivity of the method, and the results will be presented.

  13. The 'KATOD-1' strip readout ASIC for cathode strip chamber

    International Nuclear Information System (INIS)

    Golutvin, I.A.; Gorbunov, N.V.; Karzhavin, V.Yu.; Khabarov, V.S.; Movchan, S.A.; Smolin, D.A.; Dvornikov, O.V.; Shumejko, N.M.; Chekhovskij, V.A.

    2001-01-01

    The 'KATOD-1', a 16-channels readout ASIC, has been designed to perform tests of P3 and P4 full-scale prototypes of the cathode strip chamber for the ME1/1 forward muon station of the Compact Muon Solenoid (CMS) experiment. The ASIC channel consists of two charge-sensitive preamplifiers, a three-stage shaper with cancellation, and an output driver. The ASIC is instrumented with control of gain, in the range of (-4.2 : +5.0) mV/fC, and control of output pulse-shape. The equivalent input noise is equal to 2400 e with the slope of 12 e/pF for detector capacity up to 200 pF. The peaking time is 100 ns for the chamber signal. The ASIC has been produced by a microwave Bi-jFET technology

  14. The "KATOD-1" Strip Readout ASIC for Cathode Strip Chamber

    CERN Document Server

    Golutvin, I A; Karjavin, V Yu; Khabarov, V S; Movchan, S A; Smolin, D A; Dvornikov, O V; Shumeiko, N M; Tchekhovski, V A

    2001-01-01

    The "KATOD-1", a 16-channels readout ASIC, has been designed to perform tests of P3 and P4 full-scale prototypes of the cathode strip chamber for the ME1/1 forward muon station of the Compact Muon Solenoid (CMS) experiment. The ASIC channel consists of two charge-sensitive preamplifiers, a three-stage shaper with tail cancellation, and an output driver. The ASIC is instrumented with control of gain, in the range of (-4.2\\div +5.0) mV/fC, and control of output pulse-shape. The equivalent input noise is equal to 2400 e with the slope of 12 e/pF for detector capacity up to 200 pF. The peaking time is 100 ns for the chamber signal. The ASIC has been produced by a microwave Bi-jFET technology.

  15. Performance of a Novel Hydrophobic Mesoporous Material for High Temperature Catalytic Oxidation of Naphthalene

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available A high surface area, hydrophobic mesoporous material, MFS, has been successfully synthesized by a hydrothermal synthesis method using a perfluorinated surfactant, SURFLON S-386, as the single template. N2 adsorption and TEM were employed to characterize the pore structure and morphology of MFS. Static water adsorption test indicates that the hydrophobicity of MFS is significantly higher than that of MCM-41. XPS and Py-GC/MS analysis confirmed the existence of perfluoroalkyl groups in MFS which led to its high hydrophobicity. MFS was used as a support for CuO in experiments of catalytic combustion of naphthalene, where it showed a significant advantage over MCM-41 and ZSM-5. SEM was helpful in understanding why CuO-MFS performed so well in the catalytic combustion of naphthalene. Experimental results indicated that MFS was a suitable support for catalytic combustion of large molecular organic compounds, especially for some high temperature catalytic reactions when water vapor was present.

  16. Catalytic nanoporous membranes

    Science.gov (United States)

    Pellin, Michael J; Hryn, John N; Elam, Jeffrey W

    2013-08-27

    A nanoporous catalytic membrane which displays several unique features Including pores which can go through the entire thickness of the membrane. The membrane has a higher catalytic and product selectivity than conventional catalysts. Anodic aluminum oxide (AAO) membranes serve as the catalyst substrate. This substrate is then subjected to Atomic Layer Deposition (ALD), which allows the controlled narrowing of the pores from 40 nm to 10 nm in the substrate by deposition of a preparatory material. Subsequent deposition of a catalytic layer on the inner surfaces of the pores reduces pore sizes to less than 10 nm and allows for a higher degree of reaction selectivity. The small pore sizes allow control over which molecules enter the pores, and the flow-through feature can allow for partial oxidation of reactant species as opposed to complete oxidation. A nanoporous separation membrane, produced by ALD is also provided for use in gaseous and liquid separations. The membrane has a high flow rate of material with 100% selectivity. Also provided is a method for producing a catalytic membrane having flow-through pores and discreet catalytic clusters adhering to the inside surfaces of the pores.

  17. Adsorption--from theory to practice.

    Science.gov (United States)

    Dabrowski, A

    2001-10-08

    Adsorption at various interfaces has concerned scientists since the beginning of this century. This phenomenon underlies a number of extremely important processes of utilitarian significance. The technological, environmental and biological importance of adsorption can never be in doubt. Its practical applications in industry and environmental protection are of paramount importance. The adsorption of substrates is the first stage in many catalytic processes. The methods for separation of mixtures on a laboratory and on an industrial scale are increasingly based on utilising the change in concentration of components at the interface. Moreover, such vital problems as purification of water, sewages, air and soil are involved here too. On the other hand, many areas in which technological innovation has covered adsorption phenomena have been expanded more through art and craft than through science. A basic understanding of the scientific principles is far behind; in part because the study of interfaces requires extremely careful experimentation if meaningful and reproducible results are to be obtained. In recent years, however, considerable effort has been increasingly directed toward closing the gap between theory and practice. Crucial progress in theoretical description of the adsorption has been achieved, mainly through the development of new theoretical approaches formulated on a molecular level, by means of computer simulation methods and owing to new techniques which examine surface layers or interfacial regions. Moreover, during the last 15 years new classes of solid adsorbents have been developed, such as activated carbon fibres and carbon molecular sieves, fullerenes and heterofullerenes, microporous glasses and nanoporous--both carbonaceous and inorganic--materials. Nanostructured solids are very popular in science and technology and have gained extreme interest due to their sorption, catalytic, magnetic, optical and thermal properties. Although the development

  18. Mechanical behaviour of a creased thin strip

    Directory of Open Access Journals (Sweden)

    J. Liu

    2018-02-01

    Full Text Available In this study the mechanical behaviour of a creased thin strip under opposite-sense bending was investigated. It was found that a simple crease, which led to the increase of the second moment of area, could significantly alter the overall mechanical behaviour of a thin strip, for example the peak moment could be increased by 100 times. The crease was treated as a cylindrical segment of a small radius. Parametric studies demonstrated that the geometry of the strip could strongly influence its flexural behaviour. We showed that the uniform thickness and the radius of the creased segment had the greatest and the least influence on the mechanical behaviour, respectively. We further revealed that material properties could dramatically affect the overall mechanical behaviour of the creased strip by gradually changing the material from being linear elastic to elastic-perfect plastic. After the formation of the fold, the moment of the two ends of the strip differed considerably when the elasto-plastic materials were used, especially for materials with smaller tangent modulus in the plastic range. The deformation patterns of the thin strips from the finite element simulations were verified by physical models made of thin metal strips. The findings from this study provide useful information for designing origami structures for engineering applications using creased thin strips.

  19. Nuclear reactor spring strip grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Flora, B.S.

    1978-01-01

    A bimetallic grid spacer is described comprising a grid structure of zircaloy formed by intersecting striplike members which define fuel element openings for receiving fuel elements and spring strips made of Inconel positioned within the grid structure for cooperating with the fuel elements to maintain them in their desired position. A plurality of these spring strips extend longitudinally between sides of the grid structure, being locked in position by the grid retaining strips. The fuel rods, which are disposed in the fuel openings formed in the grid structure, are positioned by means of the springs associated with the spring strips and a plurality of dimples which extend from the zircaloy grid structure into the openings. In one embodiment the strips are disposed in a plurality of arrays with those spring strip arrays situated in opposing diagonal quadrants of the grid structure extending in the same direction and adjacent spring strip arrays in each half of the spacer extending in relatively perpendicular directions. Other variations of the spring strip arrangements for a particular fuel design are disclosed herein

  20. CMS Silicon Strip Tracker Performance

    CERN Document Server

    Agram, Jean-Laurent

    2012-01-01

    The CMS Silicon Strip Tracker (SST), consisting of 9.6 million readout channels from 15148 modules and covering an area of 198 square meters, needs to be precisely calibrated in order to correctly reconstruct the events recorded. Calibration constants are derived from different workflows, from promptly reconstructed events with particles as well as from commissioning events gathered just before the acquisition of physics runs. The performance of the SST has been carefully studied since the beginning of data taking: the noise of the detector, data integrity, signal-over-noise ratio, hit reconstruction efficiency and resolution have been all investigated with time and for different conditions. In this paper we describe the reconstruction strategies, the calibration procedures and the detector performance results from the latest CMS operation.

  1. The CMS silicon strip tracker

    International Nuclear Information System (INIS)

    Focardi, E.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Bartalini, P.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Civinini, C.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell'Orso, R.; Marina, R. Della; Dutta, S.; Eklund, C.; Elliott-Peisert, A.; Feld, L.; Fiore, L.; French, M.; Freudenreich, K.; Fuertjes, A.; Giassi, A.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammerstrom, R.; Hebbeker, T.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B. Mc; Meschini, M.; Messineo, A.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Raffaelli, F.; Raso, G.; Raymond, M.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Skog, K.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Wang, Y.; Watts, S.; Wittmer, B.

    1999-01-01

    The Silicon Strip Tracker (SST) is the intermediate part of the CMS Central Tracker System. SST is based on microstrip silicon devices and in combination with pixel detectors and the Microstrip Gas Chambers aims at performing pattern recognition, track reconstruction and momentum measurements for all tracks with p T ≥2 GeV/c originating from high luminosity interactions at √s=14 TeV at LHC. We aim at exploiting the advantages and the physics potential of the precise tracking performance provided by the microstrip silicon detectors on a large scale apparatus and in a much more difficult environment than ever. In this paper we describe the actual SST layout and the readout system. (author)

  2. Steam reformer with catalytic combustor

    Science.gov (United States)

    Voecks, Gerald E. (Inventor)

    1990-01-01

    A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

  3. Catalytic dehydration of ethanol using transition metal oxide catalysts.

    Science.gov (United States)

    Zaki, T

    2005-04-15

    The aim of this work is to study catalytic ethanol dehydration using different prepared catalysts, which include Fe(2)O(3), Mn(2)O(3), and calcined physical mixtures of both ferric and manganese oxides with alumina and/or silica gel. The physicochemical properties of these catalysts were investigated via X-ray powder diffraction (XRD), acidity measurement, and nitrogen adsorption-desorption at -196 degrees C. The catalytic activities of such catalysts were tested through conversion of ethanol at 200-500 degrees C using a catalytic flow system operated under atmospheric pressure. The results obtained indicated that the dehydration reaction on the catalyst relies on surface acidity, whereas the ethylene production selectivity depends on the catalyst chemical constituents.

  4. Ultrasonic examination of JBK-75 strip material

    International Nuclear Information System (INIS)

    Cook, K.V.; Cunningham, R.A. Jr.; Lewis, J.C.; McClung, R.W.

    1982-12-01

    An ultrasonic inspection system was assembled to inspect the JBK-75 stainless steel sheath material (for the Large Coil Project) for the Westinghouse-Airco superconducting magnet program. The mechanical system provided for handling the 180-kg (400-lb) coils of strip material [1.6 mm thick by 78 mm wide by 90 to 120 m long (0.064 by 3.07 in. by 300 to 400 ft)], feeding the strip through the ultrasonic inspection and cleaning stations, and respooling the coils. We inspected 54 coils of strip for both longitudinal and laminar flaws. Simulated flaws were used to calibrate both inspections. Saw-cut notches [0.28 mm deep (0.011 in., about 17% of the strip thickness)] were used to calibrate the longitudinal flaw inspections; 1.59-mm-diam (0.063-in.) flat-bottom holes drilled halfway through a calibration strip were used to calibrate the laminar flaw tests

  5. Model for prediction of strip temperature in hot strip steel mill

    International Nuclear Information System (INIS)

    Panjkovic, Vladimir

    2007-01-01

    Proper functioning of set-up models in a hot strip steel mill requires reliable prediction of strip temperature. Temperature prediction is particularly important for accurate calculation of rolling force because of strong dependence of yield stress and strip microstructure on temperature. A comprehensive model was developed to replace an obsolete model in the Western Port hot strip mill of BlueScope Steel. The new model predicts the strip temperature evolution from the roughing mill exit to the finishing mill exit. It takes into account the radiative and convective heat losses, forced flow boiling and film boiling of water at strip surface, deformation heat in the roll gap, frictional sliding heat, heat of scale formation and the heat transfer between strip and work rolls through an oxide layer. The significance of phase transformation was also investigated. Model was tested with plant measurements and benchmarked against other models in the literature, and its performance was very good

  6. Model for prediction of strip temperature in hot strip steel mill

    Energy Technology Data Exchange (ETDEWEB)

    Panjkovic, Vladimir [BlueScope Steel, TEOB, 1 Bayview Road, Hastings Vic. 3915 (Australia)]. E-mail: Vladimir.Panjkovic@BlueScopeSteel.com

    2007-10-15

    Proper functioning of set-up models in a hot strip steel mill requires reliable prediction of strip temperature. Temperature prediction is particularly important for accurate calculation of rolling force because of strong dependence of yield stress and strip microstructure on temperature. A comprehensive model was developed to replace an obsolete model in the Western Port hot strip mill of BlueScope Steel. The new model predicts the strip temperature evolution from the roughing mill exit to the finishing mill exit. It takes into account the radiative and convective heat losses, forced flow boiling and film boiling of water at strip surface, deformation heat in the roll gap, frictional sliding heat, heat of scale formation and the heat transfer between strip and work rolls through an oxide layer. The significance of phase transformation was also investigated. Model was tested with plant measurements and benchmarked against other models in the literature, and its performance was very good.

  7. Interfacial adsorption of insulin - Conformational changes and reversibility of adsorption

    NARCIS (Netherlands)

    Mollmann, SH; Jorgensen, L; Bukrinsky, JT; Elofsson, U; Norde, W; Frokjaer, S

    The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

  8. Adsorption of sulfur dioxide on ammonia-treated activated carbon fibers

    Science.gov (United States)

    Mangun, C.L.; DeBarr, J.A.; Economy, J.

    2001-01-01

    A series of activated carbon fibers (ACFs) and ammonia-treated ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore volume, and pore surface chemistry on adsorption of sulfur dioxide and its catalytic conversion to sulfuric acid. As expected, the incorporation of basic functional groups into the ACFs was shown as an effective method for increasing adsorption of sulfur dioxide. The adsorption capacity for dry SO2 did not follow specific trends; however the adsorption energies calculated from the DR equation were found to increase linearly with nitrogen content for each series of ACFs. Much higher adsorption capacities were achieved for SO2 in the presence of oxygen and water due to its catalytic conversion to H2SO4. The dominant factor for increasing adsorption of SO2 from simulated flue gas for each series of fibers studied was the weight percent of basic nitrogen groups present. In addition, the adsorption energies calculated for dry SO2 were shown to be linearly related to the adsorption capacity of H2SO4 from this flue gas for all fibers. It was shown that optimization of this parameter along with the pore volume results in higher adsorption capacities for removal of SO2 from flue gases. ?? 2001 Elsevier Science Ltd. All rights reserved.

  9. Catalytic pyrolysis of hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Vail' eva, N A; Buyanov, R A

    1979-01-01

    Catalytic pyrolysis of petroleum fractions (undecane) was performed with the object of clarifying such questions as the mechanism of action of the catalyst, the concepts of activity and selectivity of the catalyst, the role of transport processes, the temperature ranges and limitations of the catalytic process, the effect of the catalyst on secondary processes, and others. Catalysts such as quartz, MgO, Al/sub 2/O/sub 3/, were used. Analysis of the experimental findings and the fact that the distribution of products is independent of the nature of the surface, demonstrate that the pyrolysis of hydrocarbons in the presence of catalysts is based on the heterogeneous-homogeneous radical-chain mechanism of action, and that the role of the catalysts reduces to increasing the concentration of free radicals. The concept of selectivity cannot be applied to catalysts here, since they do not affect the mechanism of the unfolding of the process of pyrolysis and their role consists solely in initiating the process. In catalytic pyrolysis the concepts of kinetic and diffusive domains of unfolding of the catalytic reaction do not apply, and only the outer surface of the catalyst is engaged, whereas the inner surface merely promotes deletorious secondary processes reducing the selectivity of the process and the activity of the catalyst. 6 references, 2 figures.

  10. Catalytic Conversion of Biofuels

    DEFF Research Database (Denmark)

    Jørgensen, Betina

    This thesis describes the catalytic conversion of bioethanol into higher value chemicals. The motivation has been the unavoidable coming depletion of the fossil resources. The thesis is focused on two ways of utilising ethanol; the steam reforming of ethanol to form hydrogen and the partial oxida...

  11. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

    Preferred Customer

    acetylchlorophosphonazo(CPApA) by hydrogen peroxide in 0.10 M phosphoric acid. A novel catalytic kinetic-spectrophotometric method is proposed for the determination of copper based on this principle. Copper(II) can be determined spectrophotometrically ...

  12. Catalytic methanol dissociation

    International Nuclear Information System (INIS)

    Alcinikov, Y.; Fainberg, V.; Garbar, A.; Gutman, M.; Hetsroni, G.; Shindler, Y.; Tatrtakovsky, L.; Zvirin, Y.

    1998-01-01

    Results of the methanol dissociation study on copper/potassium catalyst with alumina support at various temperatures are presented. The following gaseous and liquid products at. The catalytic methanol dissociation is obtained: hydrogen, carbon monoxide, carbon dioxide, methane, and dimethyl ether. Formation rates of these products are discussed. Activation energies of corresponding reactions are calculated

  13. Adsorption. What else?

    OpenAIRE

    Rodrigues, Alirio E.

    2012-01-01

    [EN] Chemical Engineering today combines Molecular and Materials Engineerig and Process and Product Engineering (ChE=M2P2). Cyclic adsorptive processes (Simulated Moving Bed –SMB and Pressure Swing Adsorption-PSA) will be discussed for “old” and “new” applications making use of “old” and “new” (MOFs) adsorbent materials. After revisiting my memory as PhD student and the First Brazilian Adsorption meeting I will review the basic concepts involved in adsorption processes and then...

  14. Prototype Strip Barrel Modules for the ATLAS ITk Strip Detector

    CERN Document Server

    Sawyer, Craig; The ATLAS collaboration

    2017-01-01

    The module design for the Phase II Upgrade of the new ATLAS Inner Tracker (ITk) detector at the LHC employs integrated low mass assembly using single-sided flexible circuits with readout ASICs and a powering circuit incorporating control and monitoring of HV, LV and temperature on the module. Both readout and powering circuits are glued directly onto the silicon sensor surface resulting in a fully integrated, extremely low radiation length module which simultaneously reduces the material requirements of the local support structure by allowing a reduced width stave structure to be employed. Such a module concept has now been fully demonstrated using so-called ABC130 and HCC130 ASICs fabricated in 130nm CMOS technology to readout ATLAS12 n+-in-p silicon strip sensors. Low voltage powering for these demonstrator modules has been realised by utilising a DCDC powerboard based around the CERN FEAST ASIC. This powerboard incorporates an HV multiplexing switch based on a Panasonic GaN transistor. Control and monitori...

  15. Charge collection in silicon strip detectors

    International Nuclear Information System (INIS)

    Kraner, H.W.; Beuttenmuller, R.; Ludlam, T.; Hanson, A.L.; Jones, K.W.; Radeka, V.; Heijne, E.H.M.

    1982-11-01

    The use of position sensitive silicon detectors as very high resolution tracking devices in high energy physics experiments has been a subject of intense development over the past few years. Typical applications call for the detection of minimum ionizing particles with position measurement accuracy of 10 μm in each detector plane. The most straightforward detector geometry is that in which one of the collecting electrodes is subdivided into closely spaced strips, giving a high degree of segmentation in one coordinate. Each strip may be read out as a separate detection element, or, alternatively, resistive and/or capacitive coupling between adjacent strips may be exploited to interpolate the position via charge division measrurements. With readout techniques that couple several strips, the numer of readout channels can, in principle, be reduced by large factors without sacrificing the intrinsic position accuracy. The testing of individual strip properties and charge division between strips has been carried out with minimum ionizing particles or beams for the most part except in one case which used alphs particless scans. This paper describes the use of a highly collimated MeV proton beam for studies of the position sensing properties of representative one dimensional strip detectors

  16. Transfusion and blood donation in comic strips.

    Science.gov (United States)

    Lefrère, Jean-Jacques; Danic, Bruno

    2013-07-01

    The representation of blood transfusion and donation of blood in the comic strip has never been studied. The comic strip, which is a relatively recent art, emerged in the 19th century before becoming a mass medium during the 20th century. We have sought, by calling on collectors and using the resources of Internet, comic strips devoted, wholly or in part, to the themes of transfusion and blood donation. We present some of them here in chronologic order, indicating the title, country of origin, year of publication, and names of authors. The theme of the superhero using transfusion to transmit his virtues or his powers is repeated throughout the 20th century in North American comic strips. More recently, comic strips have been conceived from the outset with a promotional aim. They perpetuate positive images and are directed toward a young readership, wielding humor to reduce the fear of venipuncture. Few comic strips denounce the abuse of the commercialization of products derived from the human body. The image of transfusion and blood donation given by the comic strips is not to be underestimated because their readership is primarily children, some of whom will become blood donors. Furthermore, if some readers are transfused during their lives, the impact of a memory more or less conscious of these childhood readings may resurface, both in hopes and in fears. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Reactive Distillation and Air Stripping Processes for Water Recycling and Trace Contaminant Control

    Science.gov (United States)

    Boul, Peter J.; Lange, Kevin E.; Conger, Bruce; Anderson, Molly

    2009-01-01

    Reactive distillation designs are considered to reduce the presence of volatile organic compounds in the purified water. Reactive distillation integrates a reactor with a distillation column. A review of the literature in this field has revealed a variety of functional reactive columns in industry. Wastewater may be purified by a combination of a reactor and a distiller (e.g., the EWRS or VPCAR concepts) or, in principle, through a design which integrates the reactor with the distiller. A review of the literature in reactive distillation has identified some different designs in such combinations of reactor and distiller. An evaluation of reactive distillation and reactive air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

  18. Stripping voltammetry in environmental and food analysis.

    Science.gov (United States)

    Brainina, K Z; Malakhova, N A; Stojko, N Y

    2000-10-01

    The review covers over 230 papers published mostly in the last 5 years. The goal of the review is to attract the attention of researchers and users to stripping voltammetry in particular, its application in environmental monitoring and analysis of foodstuffs. The sensors employed are impregnated graphite, carbon paste, thick film carbon/graphite and thin film metallic electrodes modified in-situ or beforehand. Hanging mercury drop electrodes and mercury coated glassy carbon electrodes are also mentioned. Strip and long-lived sensors for portable instruments and flow through systems are discussed as devices for future development and application of stripping voltammetry.

  19. Hardness of approximation for strip packing

    DEFF Research Database (Denmark)

    Adamaszek, Anna Maria; Kociumaka, Tomasz; Pilipczuk, Marcin

    2017-01-01

    Strip packing is a classical packing problem, where the goal is to pack a set of rectangular objects into a strip of a given width, while minimizing the total height of the packing. The problem has multiple applications, for example, in scheduling and stock-cutting, and has been studied extensively......)-approximation by two independent research groups [FSTTCS 2016,WALCOM 2017]. This raises a questionwhether strip packing with polynomially bounded input data admits a quasi-polynomial time approximation scheme, as is the case for related twodimensional packing problems like maximum independent set of rectangles or two...

  20. Spray rolling aluminum alloy strip

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, Kevin M.; Delplanque, J.-P.; Johnson, S.B.; Lavernia, E.J.; Zhou, Y.; Lin, Y

    2004-10-10

    Spray rolling combines spray forming with twin-roll casting to process metal flat products. It consists of atomizing molten metal with a high velocity inert gas, cooling the resultant droplets in flight and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets teams with conductive cooling at the rolls to rapidly remove the alloy's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly solidified product. While similar in some ways to twin-roll casting, spray rolling has the advantage of being able to process alloys with broad freezing ranges at high production rates. This paper describes the process and summarizes microstructure and tensile properties of spray-rolled 2124 and 7050 aluminum alloy strips. A Lagrangian/Eulerian poly-dispersed spray flight and deposition model is described that provides some insight into the development of the spray rolling process. This spray model follows droplets during flight toward the rolls, through impact and spreading, and includes oxide film formation and breakup when relevant.

  1. The Panda Strip Asic: Pasta

    Science.gov (United States)

    Lai, A.

    2018-01-01

    PASTA is the 64 channel front-end chip, designed in a 110 nm CMOS technology to read out the strip sensors of the Micro Vertex Detector (MVD) of the PANDA experiment. This chip provides high resolution timestamp and deposited charge information by means of the time-over-threshold technique. Its working principle is based on a predecessor, the TOFPET ASIC, that was designed for medical applications. A general restructuring of the architecture was needed, in order to meet the specific requirements imposed by the physics programme of PANDA, especially in terms of radiation tolerance, spatial constraints, and readout in absence of a first level hardware trigger. The first revision of PASTA is currently under evaluation at the Forschungszentrum Jülich, where a data acquisition system dedicated to the MVD prototypes has been developed. This paper describes the main aspect of the chip design, gives an overview of the data acquisition system used for the verification, and shows the first results regarding the performance of PASTA.

  2. Dynamic underground stripping demonstration project

    International Nuclear Information System (INIS)

    Newmark, R.L.

    1992-04-01

    LLNL is collaborating with the UC Berkeley College of Engineering to develop and demonstrate a system of thermal remediation techniques for rapid cleanup of localized underground spills. Called dynamic stripping to reflect the rapid and controllable nature of the process, it will combine steam injection, direct electrical heating, and tomographic geophysical imaging in a cleanup of the LLNL gasoline spill. In the first eight months of the project, a Clean Site engineering test was conducted to prove the field application of the techniques. Tests then began on the contaminated site in FY 1992. This report describes the work at the Clean Site, including design and performance criteria, test results, interpretations, and conclusions. We fielded 'a wide range of new designs and techniques, some successful and some not. In this document, we focus on results and performance, lessons learned, and design and operational changes recommended for work at the contaminated site. Each section focuses on a different aspect of the work and can be considered a self-contained contribution

  3. A Simple Adsorption Experiment

    Science.gov (United States)

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  4. Insights into the Hydrothermal Stability of Triamine-Functionalized SBA-15 Silica for CO2 Adsorption.

    Science.gov (United States)

    Jahandar Lashaki, Masoud; Ziaei-Azad, Hessam; Sayari, Abdelhamid

    2017-10-23

    The hydrothermal stability of triamine-grafted, large-pore SBA-15 CO 2 adsorbents was studied by using steam stripping. Following two 3 h cycles of steam regeneration, lower CO 2 uptakes, lower CO 2 /N ratios, and slower adsorption kinetics were observed relative to fresh samples, particularly at the lowest adsorption temperature (25 °C). CO 2 adsorption measurements for a selected sample exposed to 48 h of steam stripping depicted that after the initial loss during the first exposure to steam (3-6 h), the adsorptive properties stabilized. For higher adsorption temperatures (i.e., 50 and 75 °C), however, all adsorptive properties remained almost unchanged after steaming, indicating the significance of diffusional limitations. Thermogravimetric analysis and FTIR spectroscopy on grafted samples before and after steam stripping showed no amine leaching and no change in the chemical nature of the amine groups, respectively. Also, a six-cycle CO 2 adsorption/desorption experiment under dry conditions showed no thermal degradation. However, N 2 adsorption measurement at 77 K showed significant reductions in the BET surface area of the grafted samples following steaming. Based on the pore size distribution of calcined, grafted samples before and after steaming, it is proposed that exposure to steam restructured the grafted materials, causing mass transfer resistance. It is inferred that triamine-grafted, large-pore SBA-15 adsorbents are potential candidates for CO 2 capture at relatively high temperatures (50-75 °C; for example, flue gas) combined with steam regeneration. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Radioactive nuclide adsorption

    International Nuclear Information System (INIS)

    Fukushima, Kimichika.

    1982-01-01

    Purpose: To improve the efficiency of a radioactive nuclide adsorption device by applying a nickel plating on a nickel plate to render the surface active. Constitution: A capturing device for radioactive nuclide such as manganese 54, cobalt 60, 58 and the like is disposed to the inside of a pipeway provided on the upper portion of fuel assemblies through which liquid sodium as the coolant for LMFBR type reactor is passed. The device comprises a cylindrical adsorption body and spacers. The adsorption body is made of nickel and applied with a nickel plating on the surface thereof. The surface of the adsorption body is unevened to result in disturbance in the coolant and thereby improve the adsorptive efficiency. (Kawakami, Y.)

  6. Comparative limnology of strip-mine lakes

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, J D

    1964-01-01

    Lakes were classified according to chemical properties. The concentration of the ferric iron oxides was responsible for a reddish-black turbidity which, in turn, played a major role in the thermal stratification of red strip-mine lakes. Owing to the lack of measurable turbidity and as a result of selective absorption of visible solar radiation, other strip-mine lakes appeared blue in color. The annual heat budget and the summer heat budget are essentially equivalent under saline conditions. Regardless of the physical and chemical conditions of the strip-mine lakes, heat income was a function of the circulating water mass. The progressive oxidation and precipitation of the iron oxides is the key to the classification of strip-mine lakes.

  7. Buffer Strips for Riparian Zone Management

    National Research Council Canada - National Science Library

    1991-01-01

    This study provides a review of technical literature concerning the width of riparian buffer strips needed to protect water quality and maintain other important values provided by riparian ecosystem...

  8. Concentric catalytic combustor

    Science.gov (United States)

    Bruck, Gerald J [Oviedo, FL; Laster, Walter R [Oviedo, FL

    2009-03-24

    A catalytic combustor (28) includes a tubular pressure boundary element (90) having a longitudinal flow axis (e.g., 56) separating a first portion (94) of a first fluid flow (e.g., 24) from a second portion (95) of the first fluid flow. The pressure boundary element includes a wall (96) having a plurality of separate longitudinally oriented flow paths (98) annularly disposed within the wall and conducting respective portions (100, 101) of a second fluid flow (e.g., 26) therethrough. A catalytic material (32) is disposed on a surface (e.g., 102, 103) of the pressure boundary element exposed to at least one of the first and second portions of the first fluid flow.

  9. Determination of mobile form contents of Zn, Cd, Pb and Cu in soil extracts by combined stripping voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Nedeltcheva, T. [Department of Analytical Chemistry, University of Chemical Technology and Metallurgy, 8 Kl. Ohridsi Blvd., 1756 Sofia (Bulgaria)]. E-mail: nedel@uctm.edu; Atanassova, M. [Department of Analytical Chemistry, University of Chemical Technology and Metallurgy, 8 Kl. Ohridsi Blvd., 1756 Sofia (Bulgaria); Dimitrov, J. [N. Pushkarov Institute of Soil Science and Agroecology, 7 Shosse Bankya St., 1080 Sofia (Bulgaria); Stanislavova, L. [N. Pushkarov Institute of Soil Science and Agroecology, 7 Shosse Bankya St., 1080 Sofia (Bulgaria)

    2005-01-10

    The amount of mobile forms of Zn, Pb, Cd and Cu in extracts obtained by treating soil samples with ammonium nitrate were determined by an appropriate combination of anodic and cathodic stripping voltammetry with hanging mercury drop electrode. Every analysis required three mercury drops: on the first one, zinc was determined; on the second, cadmium and lead; on the third, copper was determined. Zinc, lead and cadmium were determined by conventional differential-pulse anodic stripping voltammetry. For copper determination, adsorptive differential-pulse cathodic stripping voltammetry with amalgamation using chloride ions as a complexing agent was applied. The standard deviation of the results was from 1 to 10% depending on the metal content in the sample. Voltammetric results were in good agreement with the AAS analysis. No microwave digestion of soil extracts was necessary.

  10. Determination of mobile form contents of Zn, Cd, Pb and Cu in soil extracts by combined stripping voltammetry

    International Nuclear Information System (INIS)

    Nedeltcheva, T.; Atanassova, M.; Dimitrov, J.; Stanislavova, L.

    2005-01-01

    The amount of mobile forms of Zn, Pb, Cd and Cu in extracts obtained by treating soil samples with ammonium nitrate were determined by an appropriate combination of anodic and cathodic stripping voltammetry with hanging mercury drop electrode. Every analysis required three mercury drops: on the first one, zinc was determined; on the second, cadmium and lead; on the third, copper was determined. Zinc, lead and cadmium were determined by conventional differential-pulse anodic stripping voltammetry. For copper determination, adsorptive differential-pulse cathodic stripping voltammetry with amalgamation using chloride ions as a complexing agent was applied. The standard deviation of the results was from 1 to 10% depending on the metal content in the sample. Voltammetric results were in good agreement with the AAS analysis. No microwave digestion of soil extracts was necessary

  11. Theoretical study of adsorption of organic phosphines on transition metal surfaces

    Science.gov (United States)

    Lou, Shujie; Jiang, Hong

    2018-04-01

    The adsorption properties of organic phosphines on transition metal (TM) surfaces (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au) have been studied to explore the possibility of building novel heterogeneous chiral catalytic systems based on organic phosphines. Preferred adsorption sites, adsorption energies and surface electronic structures of a selected set of typical organic phosphines adsorbed on TM surfaces are calculated with density-functional theory to obtain a systematic understanding on the nature of adsorption interactions. All organic phosphines considered are found to chemically adsorb on these TM surfaces with the atop site as the most preferred one, and the TM-P bond is formed via the lone-pair electrons of the P atom and the directly contacted TM atom. These findings imply that it is indeed possible to build heterogeneous chiral catalytic systems based on organic phosphines adsorbed on TM surfaces, which, however, requires a careful design of molecular structure of organic phosphines.

  12. Deuteron stripping reactions using dirac phenomenology

    Science.gov (United States)

    Hawk, E. A.; McNeil, J. A.

    2001-04-01

    In this work deuteron stripping reactions are studied using the distorted wave born approximation employing dirac phenomenological potentials. In 1982 Shepard and Rost performed zero-range dirac phenomenological stripping calculations and found a dramatic reduction in the predicted cross sections when compared with similar nonrelativistic calculations. We extend the earlier work by including full finite range effects as well as the deuteron's internal D-state. Results will be compared with traditional nonrelativistic approaches and experimental data at low energy.

  13. Flexible strip supercapacitors for future energy storage

    OpenAIRE

    Zhang, R-R; Xu, Y-M; Harrison, D; Fyson, J; Qiu, F-L; Southee, D

    2015-01-01

    Flexible strip supercapacitors are developed and their electrochemical properties are characterized. Activated carbon is used as the electrode material and it is found to have a good porous structure which provides a large surface area for energy storage. Furthermore, this activated carbon performs well. The manufacturing processes for the supercapacitors are described in detail and the preparation process has good reproducibility. The strip supercapacitors are combined in series and parallel...

  14. The charge collection in silicon strip detectors

    International Nuclear Information System (INIS)

    Boehringer, T.; Hubbeling, L.; Weilhammer, P.; Kemmer, J.; Koetz, U.; Riebesell, M.; Belau, E.; Klanner, R.; Lutz, G.; Neugebauer, E.; Seebrunner, H.J.; Wylie, A.

    1983-02-01

    The charge collection in silicon detectors has been studied, by measuring the response to high-energy particles of a 20μm pitch strip detector as a function of applied voltage and magnetic field. The results are well described by a simple model. The model is used to predict the spatial resolution of silicon strip detectors and to propose a detector with optimized spatial resolution. (orig.)

  15. LYCORIS - A Large Area Strip Telescope

    CERN Document Server

    Krämer, U; Stanitzki, M; Wu, M

    2018-01-01

    The LYCORIS Large Area Silicon Strip Telescope for the DESY II Test Beam Facility is presented. The DESY II Test Beam Facility provides elec- tron and positron beams for beam tests of up to 6 GeV. A new telescope with a large 10 × 20 cm2 coverage area based on a 25 μm pitch strip sensor is to be installed within the PCMAG 1 T solenoid. The current state of the system is presented.

  16. Quantitative comparison of 3 enamel-stripping devices in vitro: how precisely can we strip teeth?

    Science.gov (United States)

    Johner, Alexander Marc; Pandis, Nikolaos; Dudic, Alexander; Kiliaridis, Stavros

    2013-04-01

    In this in-vitro study, we aimed to investigate the predictability of the expected amount of stripping using 3 common stripping devices on premolars. One hundred eighty extracted premolars were mounted and aligned in silicone. Tooth mobility was tested with Periotest (Medizintechnik Gulden, Modautal, Germany) (8.3 ± 2.8 units). The selected methods for interproximal enamel reduction were hand-pulled strips (Horico, Hapf Ringleb & Company, Berlin, Germany), oscillating segmental disks (O-drive-OD 30; KaVo Dental, Biberach, Germany), and motor-driven abrasive strips (Orthofile; SDC Switzerland, Lugano-Grancia, Switzerland). With each device, the operator intended to strip 0.1, 0.2, 0.3, or 0.4 mm on the mesial side of 15 teeth. The teeth were scanned before and after stripping with a 3-dimensional laser scanner. Superposition and measurement of stripped enamel on the most mesial point of the tooth were conducted with Viewbox software (dHal Software, Kifissia, Greece). The Wilcoxon signed rank test and the Kruskal-Wallis test were applied; statistical significance was set at alpha ≤ 0.05. Large variations between the intended and the actual amounts of stripped enamel, and between stripping procedures, were observed. Significant differences were found at 0.1 mm of intended stripping (P ≤ 0.05) for the hand-pulled method and at 0.4 mm of intended stripping (P ≤ 0.001 to P = 0.05) for all methods. For all scenarios of enamel reduction, the actual amount of stripping was less than the predetermined and expected amount of stripping. The Kruskal-Wallis analysis showed no significant differences between the 3 methods. There were variations in the stripped amounts of enamel, and the stripping technique did not appear to be a significant predictor of the actual amount of enamel reduction. In most cases, actual stripping was less than the intended amount of enamel reduction. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights

  17. Catalytic exhaust control

    Energy Technology Data Exchange (ETDEWEB)

    Heinemann, H

    1973-09-01

    Recent achievements and problems in the development of exhaust control devices in the USA are reviewed. To meet the 1976 emission standards, catalytic systems for the oxidation of carbon monoxide and hydrocarbons and for the reduction of nitrogen oxides to nitrogen and water are needed. While oxidizing catalysts using platinum, palladium, copper, vanadium, and chromium appplied on alumina or ceramic materials are more or less effective in emission control, there are no catalytic devices for the reduction of nitrogen oxides with the required useful life of 25,000 to 50,000 miles as yet available. In the case of platinum catalysts on monolithic supports, the operating temperature of 650 to 750/sup 0/C as required for the oxidation process may cause inactivation of the catalysts and fusion of the support material. The oxidation of CO and hydrocarbons is inhibited by high concentrations of CO, nitric oxide, and hydrocarbons. The use of catalytic converters requires the use of lead-free or low-lead gasoline. The nitrogen oxides conversion efficiency is considerably influenced by the oxygen-to-CO ratio of the exhaust gas, which makes limitation of this ratio necessary.

  18. Transient TAP approach to investigate adsorption and diffusion of small alkanes in porous sulfated zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Galinsky, M.; Breitkopf, C. [Technische Univ. Dresden (Germany). Inst. fuer Energietechnik

    2011-07-01

    Sulfated zirconias have attracted an interest as catalysts due to their ability to isomerize alkanes at low temperatures, e.g., under thermodynamically favored conditions. However, the fast deactivation during the reaction remains a problem. To improve the catalytic performance of such porous catalysts, it is necessary to understand all steps in the catalytic cycle, namely diffusion and adsorption in more detail. The transient TAP method was applied to investigate sorption and diffusion phenomena of different alkanes in three different morphologically structured sulfated zirconias to elucidate their catalytic performances in the n-butane isomerization. New theoretical models were developed to describe the experimental results of TAP single-pulse experiments. The application of these models to pulse response curves allowed the extraction of adsorption and desorption rate constants as well as diffusion coefficients. Via introducing a second sorption center, the new adsorption model is able to reproduce the sorption behavior for larger alkanes quantitatively better than former models, especially in the low-temperature region. Moreover, the heterogeneous distribution of active centers was taken into account. Temperature dependent measurements have been performed to calculate heats of adsorption for various alkanes at the two assumed adsorption sites. The impact of these values on the catalytic properties is discussed. With the help of the new diffusion model, the diffusion coefficients for the inter- and intrapellet volume could be determined. These values are used in a numerical simulation to check whether the reaction rate for the isomerization at the investigated sulfated zirconias is diffusion limited. (orig.)

  19. New separation technique. Catalytically functionated separation membrane

    Energy Technology Data Exchange (ETDEWEB)

    Urgami, Tadashi [Kansai Univ., Osaka (Japan)

    1989-02-01

    This report introduces research examples, showing the fundamental principle of the membrane by separating the catalytically functionated separation membrane into enzyme fixing separation membrane, polymerized metal complex separation membrane and polymer catalyst separation membrane. This membrane can achieve both functions of separation and catalytic reaction simultaneously and has sufficient possibility to combine powerful functions. Enzyme fixing separation membrane is prepared by carrier combination method, bridging method or covering method and the enzyme fixing method with polymerized complex in which enzyme is controlled to prevent the activity lowering as much as possible and enzyme is fixed from an aqueous solution into polymer membrane. This membrane is applied to the continuous manufacturing of invert sugar from cane sugar and adsorption and removing of harmful substances from blood by utilizing both micro-capsuled urease and active carbon. Alginic acid-copper (II) complex membrane is used for the polymerized metal complex membrane and polystyrene sulfonate membrane is used for the polymer catalyst separation membrane. 28 refs., 4 figs., 1 tabs.

  20. Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

    Directory of Open Access Journals (Sweden)

    Qing Chen

    2017-01-01

    Full Text Available Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indicates that nitrogen adsorption on shale includes monolayer adsorption, multilayer adsorption, and capillary condensation. Usually, Langmuir isotherm is a monolayer adsorption model for ideal interfaces; BET (Brunauer, Emmett, Teller adsorption isotherm is a multilayer adsorption model based on specific assumptions; Freundlich isotherm is an empirical equation widely applied in liquid phase adsorption. In this study, a new nitrogen adsorption isotherm is applied to simultaneously depict monolayer adsorption, multilayer adsorption, and capillary condensation, which provides more real and accurate representation of nitrogen adsorption on shale. In addition, parameters are discussed in relation to heat of adsorption which is relevant to the shape of the adsorption isotherm curve. The curve fitting results indicate that our new nitrogen adsorption isotherm can appropriately describe the whole process of nitrogen adsorption on shale.

  1. Ozone adsorption on carbon nanoparticles

    Science.gov (United States)

    Chassard, Guillaume; Gosselin, Sylvie; Visez, Nicolas; Petitprez, Denis

    2014-05-01

    Carbonaceous particles produced by incomplete combustion or thermal decomposition of hydrocarbons are ubiquitous in the atmosphere. On these particles are adsorbed hundreds of chemical species. Those of great concern to health are polycyclic aromatic hydrocarbons (PAHs). During atmospheric transport, particulate PAHs react with gaseous oxidants. The induced chemical transformations may change toxicity and hygroscopicity of these potentially inhalable particles. The interaction between ozone and carbon particles has been extensively investigated in literature. However ozone adsorption and surface reaction mechanisms are still ambiguous. Some studies described a fast catalytic decomposition of ozone initiated by an atomic oxygen chemisorption followed by a molecular oxygen release [1-3]. Others suggested a reversible ozone adsorption according to Langmuir-type behaviour [4,5]. The aim of this present study is a better understanding of ozone interaction with carbon surfaces. An aerosol of carbon nanoparticles was generated by flowing synthetic air in a glass tube containing pure carbon (primary particles studied. Accordingly to literature, it has been observed that the number of gas-phase ozone molecules lost per unit particle surface area tends towards a plateau for high ozone concentration suggesting a reversible ozone adsorption according to a Langmuir mechanism. We calculated the initial reaction probability between O3 and carbon particles.An initial uptake coefficient of 1.10-4 was obtained. Similar experiments were realized by selecting the particles size with a differential mobility analyser. We observed a strong size-dependent increase in reactivity with the decrease of particles size. This result is relevant for the health issues. Indeed the smallest particles are most likely to penetrate deep into the lungs. Competitive reactions between ozone and other species like H2O or atomic oxygen were also considered. Oxygen atoms were generated by photolysis of O3

  2. adsorption, eosin, humic, peat

    OpenAIRE

    anshar, andi muhammad

    2015-01-01

    Eosin is one of the dyes commonly used in the industry and has the potential to cause pollution of the water environment. The Eosin pollution treatment methods used in this study was the adsorption method using humin fraction obtained from the peat land comes from Kalimantan. From the research data showed that the adsorption of eosin in humin result of washing with HCl / HF optimum at pH 4 and a contact time of 60 minutes with the adsorption-order rate was 8,4 x 10-3 min-1

  3. Anodic stripping voltammetric determination of heavy metals in solutions containing humic acids

    International Nuclear Information System (INIS)

    Labuda, J.; Saur, D.; Neeb, R.

    1994-01-01

    Various simultaneous effects of humic acids on the current and potential of differential pulse anodic stripping peaks of copper, lead, cadmium and zinc in weakly alkaline and acidic (pH 2) solutions have been investigated and interpreted with regard to metal complexation and the adsorption of humic acid on the mercury electrode. The applicability of the standard additions method for metal quantitation and the experimental conditions for UV-photolysis with a high-pressure mercury lamp have been examined in model as well as real water samples. (orig.)

  4. Removal of semivolatiles from soils by steam stripping. 1. A local equilibrium model

    International Nuclear Information System (INIS)

    Wilson, D.J.; Clarke, A.N.

    1992-01-01

    A mathematical model for the in-situ steam stripping of volatile and semivolatile organics from contaminated vadose zone soils at hazardous waste sites is developed. A single steam injection well is modeled. The model assumes that the pneumatic permeability of the soil is spatially constant and isotropic, that the adsorption isotherm of the contaminant is linear, and that the local equilibrium approximation is adequate. The model is used to explore the streamlines and transit times of the injected steam as well as the effects of injection well depth and contaminant distribution on the time required for remediation

  5. Competitive Protein Adsorption - Multilayer Adsorption and Surface Induced Protein Aggregation

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2009-01-01

    In this study, competitive adsorption of albumin and IgG (immunoglobulin G) from human serum solutions and protein mixtures onto polymer surfaces is studied by means of radioactive labeling. By using two different radiolabels (125I and 131I), albumin and IgG adsorption to polymer surfaces...... is monitored simultaneously and the influence from the presence of other human serum proteins on albumin and IgG adsorption, as well as their mutual influence during adsorption processes, is investigated. Exploring protein adsorption by combining analysis of competitive adsorption from complex solutions...... of high concentration with investigation of single protein adsorption and interdependent adsorption between two specific proteins enables us to map protein adsorption sequences during competitive protein adsorption. Our study shows that proteins can adsorb in a multilayer fashion onto the polymer surfaces...

  6. Novel fungal FAD glucose dehydrogenase derived from Aspergillus niger for glucose enzyme sensor strips.

    Science.gov (United States)

    Sode, Koji; Loew, Noya; Ohnishi, Yosuke; Tsuruta, Hayato; Mori, Kazushige; Kojima, Katsuhiro; Tsugawa, Wakako; LaBelle, Jeffrey T; Klonoff, David C

    2017-01-15

    In this study, a novel fungus FAD dependent glucose dehydrogenase, derived from Aspergillus niger (AnGDH), was characterized. This enzyme's potential for the use as the enzyme for blood glucose monitor enzyme sensor strips was evaluated, especially by investigating the effect of the presence of xylose during glucose measurements. The substrate specificity of AnGDH towards glucose was investigated, and only xylose was found as a competing substrate. The specific catalytic efficiency for xylose compared to glucose was 1.8%. The specific activity of AnGDH for xylose at 5mM concentration compared to glucose was 3.5%. No other sugars were used as substrate by this enzyme. The superior substrate specificity of AnGDH was also demonstrated in the performance of enzyme sensor strips. The impact of spiking xylose in a sample with physiological glucose concentrations on the sensor signals was investigated, and it was found that enzyme sensor strips using AnGDH were not affected at all by 5mM (75mg/dL) xylose. This is the first report of an enzyme sensor strip using a fungus derived FADGDH, which did not show any positive bias at a therapeutic level xylose concentration on the signal for a glucose sample. This clearly indicates the superiority of AnGDH over other conventionally used fungi derived FADGDHs in the application for SMBG sensor strips. The negligible activity of AnGDH towards xylose was also explained on the basis of a 3D structural model, which was compared to the 3D structures of A. flavus derived FADGDH and of two glucose oxidases. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Catalytic biomass pyrolysis process

    Science.gov (United States)

    Dayton, David C.; Gupta, Raghubir P.; Turk, Brian S.; Kataria, Atish; Shen, Jian-Ping

    2018-04-17

    Described herein are processes for converting a biomass starting material (such as lignocellulosic materials) into a low oxygen containing, stable liquid intermediate that can be refined to make liquid hydrocarbon fuels. More specifically, the process can be a catalytic biomass pyrolysis process wherein an oxygen removing catalyst is employed in the reactor while the biomass is subjected to pyrolysis conditions. The stream exiting the pyrolysis reactor comprises bio-oil having a low oxygen content, and such stream may be subjected to further steps, such as separation and/or condensation to isolate the bio-oil.

  8. Catalytic reforming methods

    Science.gov (United States)

    Tadd, Andrew R; Schwank, Johannes

    2013-05-14

    A catalytic reforming method is disclosed herein. The method includes sequentially supplying a plurality of feedstocks of variable compositions to a reformer. The method further includes adding a respective predetermined co-reactant to each of the plurality of feedstocks to obtain a substantially constant output from the reformer for the plurality of feedstocks. The respective predetermined co-reactant is based on a C/H/O atomic composition for a respective one of the plurality of feedstocks and a predetermined C/H/O atomic composition for the substantially constant output.

  9. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  10. Co adsorption in kaolinite

    International Nuclear Information System (INIS)

    Souza, Eliel S.; Silva, Paulo S.C.

    2017-01-01

    Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kaolinite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activated kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized parameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process. (author)

  11. Co adsorption in kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Eliel S.; Silva, Paulo S.C., E-mail: eliel201019@hotmail.com, E-mail: pscsilva@ipen.br [Instituto de Pesquisas Energética s e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kaolinite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activated kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized parameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process. (author)

  12. Development of floating strip micromegas detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bortfeldt, Jonathan

    2014-04-28

    Micromegas are high-rate capable, high-resolution micro-pattern gaseous detectors. Square meter sized resistive strip Micromegas are foreseen as replacement of the currently used precision tracking detectors in the Small Wheel, which is part of the forward region of the ATLAS muon spectrometer. The replacement is necessary to ensure tracking and triggering performance of the muon spectrometer after the luminosity increase of the Large Hadron Collider beyond its design value of 10{sup 34} cm{sup -2}s{sup -1} around 2020. In this thesis a novel discharge tolerant floating strip Micromegas detector is presented and described. By individually powering copper anode strips, the effects of a discharge are confined to a small region of the detector. This reduces the impact of discharges on the efficiency by three orders of magnitude, compared to a standard Micromegas. The physics of the detector is studied and discussed in detail. Several detectors are developed: A 6.4 x 6.4 cm{sup 2} floating strip Micromegas with exchangeable SMD capacitors and resistors allows for an optimization of the floating strip principle. The discharge behavior is investigated on this device in depth. The microscopic structure of discharges is quantitatively explained by a detailed detector simulation. A 48 x 50 cm{sup 2} floating strip Micromegas is studied in high energy pion beams. Its homogeneity with respect to pulse height, efficiency and spatial resolution is investigated. The good performance in high-rate background environments is demonstrated in cosmic muon tracking measurements with a 6.4 x 6.4 cm{sup 2} floating strip Micromegas under lateral irradiation with 550 kHz 20 MeV proton beams. A floating strip Micromegas doublet with low material budget is developed for ion tracking without limitations from multiple scattering in imaging applications during medical ion therapy. Highly efficient tracking of 20 MeV protons at particle rates of 550 kHz is possible. The reconstruction of the

  13. Development of floating strip micromegas detectors

    International Nuclear Information System (INIS)

    Bortfeldt, Jonathan

    2014-01-01

    Micromegas are high-rate capable, high-resolution micro-pattern gaseous detectors. Square meter sized resistive strip Micromegas are foreseen as replacement of the currently used precision tracking detectors in the Small Wheel, which is part of the forward region of the ATLAS muon spectrometer. The replacement is necessary to ensure tracking and triggering performance of the muon spectrometer after the luminosity increase of the Large Hadron Collider beyond its design value of 10 34 cm -2 s -1 around 2020. In this thesis a novel discharge tolerant floating strip Micromegas detector is presented and described. By individually powering copper anode strips, the effects of a discharge are confined to a small region of the detector. This reduces the impact of discharges on the efficiency by three orders of magnitude, compared to a standard Micromegas. The physics of the detector is studied and discussed in detail. Several detectors are developed: A 6.4 x 6.4 cm 2 floating strip Micromegas with exchangeable SMD capacitors and resistors allows for an optimization of the floating strip principle. The discharge behavior is investigated on this device in depth. The microscopic structure of discharges is quantitatively explained by a detailed detector simulation. A 48 x 50 cm 2 floating strip Micromegas is studied in high energy pion beams. Its homogeneity with respect to pulse height, efficiency and spatial resolution is investigated. The good performance in high-rate background environments is demonstrated in cosmic muon tracking measurements with a 6.4 x 6.4 cm 2 floating strip Micromegas under lateral irradiation with 550 kHz 20 MeV proton beams. A floating strip Micromegas doublet with low material budget is developed for ion tracking without limitations from multiple scattering in imaging applications during medical ion therapy. Highly efficient tracking of 20 MeV protons at particle rates of 550 kHz is possible. The reconstruction of the track inclination in a single

  14. Structure sensitivity in adsorption

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Nielsen, Ole Holm; Nørskov, Jens Kehlet

    1997-01-01

    The structure sensitivity of CO adsorption on different flat, stepped, kinked and reconstructed Pt surfaces is studied using large-scale density-functional calculations. We find an extremely strong structure sensitivity in the adsorption energy with variations up to 1 eV (or 100%) from one...... structure to the next. We propose a model to explain this behavior, and use it to discuss more generally the origin of structure sensitivity in heterogeneous catalysis....

  15. Superconducting nano-strip particle detectors

    International Nuclear Information System (INIS)

    Cristiano, R; Ejrnaes, M; Casaburi, A; Zen, N; Ohkubo, M

    2015-01-01

    We review progress in the development and applications of superconducting nano-strip particle detectors. Particle detectors based on superconducting nano-strips stem from the parent devices developed for single photon detection (SSPD) and share with them ultra-fast response times (sub-nanosecond) and the ability to operate at a relatively high temperature (2–5 K) compared with other cryogenic detectors. SSPDs have been used in the detection of electrons, neutral and charged ions, and biological macromolecules; nevertheless, the development of superconducting nano-strip particle detectors has mainly been driven by their use in time-of-flight mass spectrometers (TOF-MSs) where the goal of 100% efficiency at large mass values can be achieved. Special emphasis will be given to this case, reporting on the great progress which has been achieved and which permits us to overcome the limitations of existing mass spectrometers represented by low detection efficiency at large masses and charge/mass ambiguity. Furthermore, such progress could represent a breakthrough in the field. In this review article we will introduce the device concept and detection principle, stressing the peculiarities of the nano-strip particle detector as well as its similarities with photon detectors. The development of parallel strip configuration is introduced and extensively discussed, since it has contributed to the significant progress of TOF-MS applications. (paper)

  16. Properties isotropy of magnesium alloy strip workpieces

    Directory of Open Access Journals (Sweden)

    Р. Кавалла

    2016-12-01

    Full Text Available The paper discusses the issue of obtaining high quality cast workpieces of magnesium alloys produced by strip roll-casting. Producing strips of magnesium alloys by combining the processes of casting and rolling when liquid melt is fed continuously to fast rolls is quite promising and economic. In the process of sheet stamping considerable losses of metal occur on festoons formed due to anisotropy of properties of foil workpiece, as defined by the macro- and microstructure and modes of rolling and annealing. The principal causes of anisotropic mechanical properties of metal strips produced by the combined casting and rolling technique are the character of distribution of intermetallic compounds in the strip, orientation of phases of metal defects and the residual tensions. One of the tasks in increasing the output of fit products during stamping operations consists in minimizing the amount of defects. To lower the level of anisotropy in mechanical properties various ways of treating the melt during casting are suggested. Designing the technology of producing strips of magnesium alloys opens a possibility of using them in automobile industry to manufacture light-weight body elements instead of those made of steel.

  17. Area specific stripping factors for AGS. A method for extracting stripping factors from survey data

    Energy Technology Data Exchange (ETDEWEB)

    Aage, H.K.; Korsbech, U. [Technical Univ. of Denmark (Denmark)

    2006-04-15

    In order to use Airborne Gamma-ray Spectrometry (AGS) for contamination mapping, for source search etc. one must to be able to eliminate the contribution to the spectra from natural radioactivity. This in general is done by a stripping technique. The parameters for performing a stripping have until recently been measured by recording gamma spectra at special calibration sites (pads). This may be cumbersome and the parameters may not be correct when used at low gamma energies for environmental spectra. During 2000-2001 DTU tested with success a new technique for Carborne Gamma-ray Spectrometry (CGS) where the spectra from the surveyed area (or from a similar area) were used for calculating the stripping parameters. It was possible to calculate usable stripping ratios for a number of low energy windows - and weak source signals not detectable by other means were discovered with the ASS technique. In this report it is shown that the ASS technique also works for AGS data, and it has been used for recent Danish AGS tests with point sources. (Check of calibration of AGS parameters.) By using the ASS technique with the Boden data (Barents Rescue) an exercise source was detected that has not been detected by any of the teams during the exercise. The ASS technique therefore seems to be better for search for radiation anomalies than any other method known presently. The experiences also tell that although the stripping can be performed correctly at any altitude there is a variation of the stripping parameters with altitude that has not yet been quite understood. However, even with the oddly variations the stripping worked as expected. It was also observed that one might calculate a single common set of usable stripping factors for all altitudes from the entire data set i.e. some average a, b and c values. When those stripping factors were used the stripping technique still worked well. (au)

  18. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  19. Heterogeneous kinetic modeling of the catalytic conversion of cycloparaffins

    Science.gov (United States)

    Al-Sabawi, Mustafa N.

    catalytic conversions respectively, are reported. Using these data, heterogeneous kinetic models accounting for intracrystallite molecular transport, adsorption and thermal and catalytic cracking of both cycloparaffin reactants are established. Results show that undesirable hydrogen transfer reactions are more pronounced and selectively favoured against other reactions at lower reaction temperatures, while the desirable ring-opening and cracking reactions predominate at the higher reaction temperatures. Moreover, results of the present work show that while crystallite size may have an effect on the overall conversion in some situations, there is a definite effect on the selectivity of products obtained during the cracking of MCH and decalin and the cracking of MCH in a mixture with co-reactants such as 1,3,5-triisopropylbenzene. Keywords. cycloparaffins, naphthenes, fluid catalytic cracking, kinetic modeling, Y-zeolites, diffusion, adsorption, ring-opening, hydrogen transfer, catalyst selectivity.

  20. A review on adsorption refrigeration technology and adsorption deterioration in physical adsorption systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.C.; Li, Y.H. [College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Li, D.; Zhang, J.P. [College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Xia, Y.Z. [Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China)

    2010-01-15

    As one kind of environmentally friendly refrigeration, the adsorption refrigeration has attracted many attentions in resent decades. This paper introduces the researches of adsorption refrigeration systems with the commonly used working pairs, advanced adsorption cycles, heat and mass transfer enhancement and attempts of adsorption refrigeration applications. Poor heat and mass transfer problem is a bottleneck to prevent the improvements of the adsorption refrigeration technique. Two ways to enhance the heat and mass transfer are discussed in this paper. The adsorption deterioration of adsorbent, another obstacle to physical adsorption refrigeration applications, is also pointed out. And the possible reasons and the possible methods are analyzed. (author)

  1. Analysis of 'Coma strip' galaxy redshift catalog

    International Nuclear Information System (INIS)

    Klypin, A.A.; Karachentsev, I.D.; Lebedev, V.S.

    1990-01-01

    We present results of the analysis of a galaxy redshift catalog made at the 6-m telescope by Karachentsev and Kopylov (1990. Mon. Not. R. astr. Soc., 243, 390). The catalog covers a long narrow strip on the sky (10 arcmin by 63 0 ) and lists 283 galaxies up to limiting blue magnitude m B = 17.6. The strip goes through the core of Coma cluster and this is called the 'Coma strip' catalog. The catalog is almost two times deeper than the CfA redshift survey and creates the possibility of studying the galaxy distribution on scales of 100-250 Mpc. Due to the small number of galaxies in the catalog, we were able to estimate only very general and stable parameters of the distribution. (author)

  2. Catalytic oxidation of soot over alkaline niobates

    International Nuclear Information System (INIS)

    Pecchi, G.; Cabrera, B.; Buljan, A.; Delgado, E.J.; Gordon, A.L.; Jimenez, R.

    2013-01-01

    Highlights: ► No previous reported studies about alkaline niobates as catalysts for soot oxidation. ► NaNbO 3 and KNbO 3 perovskite-type oxides show lower activation energy than other lanthanoid perovskite-type oxides. ► The alkaline niobate does not show deactivation by metal loss. - Abstract: The lack of studies in the current literature about the assessment of alkaline niobates as catalysts for soot oxidation has motivated this research. In this study, the synthesis, characterization and assessment of alkaline metal niobates as catalysts for soot combustion are reported. The solids MNbO 3 (M = Li, Na, K, Rb) are synthesized by a citrate method, calcined at 450 °C, 550 °C, 650 °C, 750 °C, and characterized by AAS, N 2 adsorption, XRD, O 2 -TPD, FTIR and SEM. All the alkaline niobates show catalytic activity for soot combustion, and the activity depends basically on the nature of the alkaline metal and the calcination temperature. The highest catalytic activity, expressed as the temperature at which combustion of carbon black occurs at the maximum rate, is shown by KNbO 3 calcined at 650 °C. At this calcination temperature, the catalytic activity follows an order dependent on the atomic number, namely: KNbO 3 > NaNbO 3 > LiNbO 3 . The RbNbO 3 solid do not follow this trend presumably due to the perovskite structure was not reached. The highest catalytic activity shown by of KNbO 3 , despite the lower apparent activation energy of NaNbO 3 , stress the importance of the metal nature and suggests the hypothesis that K + ions are the active sites for soot combustion. It must be pointed out that alkaline niobate subjected to consecutive soot combustion cycles does not show deactivation by metal loss, due to the stabilization of the alkaline metal inside the perovskite structure.

  3. Outstanding catalytic activity of ultra-pure platinum nanoparticles.

    Science.gov (United States)

    Januszewska, Aneta; Dercz, Grzegorz; Piwowar, Justyna; Jurczakowski, Rafal; Lewera, Adam

    2013-12-09

    Small (4 nm) nanoparticles with a narrow size distribution, exceptional surface purity, and increased surface order, which exhibits itself as an increased presence of basal crystallographic planes, can be obtained without the use of any surfactant. These nanoparticles can be used in many applications in an as-received state and are threefold more active towards a model catalytic reaction (oxidation of ethylene glycol). Furthermore, the superior properties of this material are interesting not only due to the increase in their intrinsic catalytic activity, but also due to the exceptional surface purity itself. The nanoparticles can be used directly (i.e., as-received, without any cleaning steps) in biomedical applications (i.e., as more efficient drug carriers due to an increased number of adsorption sites) and in energy-harvesting/data-storage devices. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Solid strong base K-Pt/NaY zeolite nano-catalytic system for completed elimination of formaldehyde at room temperature

    Science.gov (United States)

    Song, Shaoqing; Wu, Xi; Lu, Changhai; Wen, Meicheng; Le, Zhanggao; Jiang, Shujuan

    2018-06-01

    Solid strong base nano-catalytic system of K-modification NaY zeolite supported 0.08% Pt (K-Pt/NaY) were constructed for eliminating HCHO at room temperature. In the catalytic process, activation energy over K-Pt/NaY nano-catalytic system was greatly decreased along with the enhanced reaction rate. Characterization and catalytic tests revealed the surface electron structure of K-Pt/NaY was improved, as reflected by the enhanced HCHO adsorption capability, high sbnd OH concentration, and low-temperature reducibility. Therefore, the optimal K-Pt/NaY showed high catalytic efficiency and strong H2O tolerance for HCHO elimination by directly promoting the reaction between active sbnd OH and formate species. These results may suggest a new way for probing the advanced solid strong base nano-catalytic system for the catalytic elimination of indoor HCHO.

  5. Test strip and method for its use

    International Nuclear Information System (INIS)

    1981-01-01

    A test strip device is described which is useful in performing binding assays involving antigens, antibodies, hormones, vitamins, metabolites or pharmacological agents. The device is capable of application to analytical methods in which a set of sequential test reactions is involved and in which a minute sample size may be used. This test strip is particularly useful in radioimmunoassays. The use of the device is illustrated in radioimmunoassays for 1) thyroxine in serum, 2) the triiodothyronine binding capacity of serum and 3) folic acid and its analogues in serum. (U.K.)

  6. Stage- vs. Channel-strip Metaphor

    DEFF Research Database (Denmark)

    Gelineck, Steven; Korsgaard, Dannie Michael; Büchert, Morten

    2015-01-01

    This study compares the stage metaphor and the channel strip metaphor in terms of performance. Traditionally, music mixing consoles employ a channels strip control metaphor for adjusting parameters such as volume and panning of each track. An alternative control metaphor, the so-called stage meta...... is surprisingly similar and thus we are not able to detect any significant difference in performance between the two interfaces. Qualitative data however, suggests that the stage metaphor is largely favoured for its intuitive interaction - confirming earlier studies....

  7. slice of LEP beamtube with getter strip

    CERN Multimedia

    1989-01-01

    A section of the LEP beam pipe. This is the chamber in which LEP's counter-rotating electron and positron beams travel. It is made of lead-clad aluminium. The beams circulate in the oval cross-section part of the chamber. In the rectangular cross-section part, LEP's innovative getter-strip vacuum pump is installed. After heating to purify the surface of the getter, the strip acts like molecular sticky tape, trapping any stray molecules left behind after the accelerator's traditional vacuum pumps have done their job.

  8. Comparative characteristics of polystyrene scintillation strips

    International Nuclear Information System (INIS)

    Gapienko, V.A.; Denisov, A.G.; Mel'nikov, E.A.

    1992-01-01

    Results are provided for a study of the main characteristics of polystyrene scintillation strips with a cross-section of 200 x 10 mm with two different scintillation-additive compositions: 1.5% p-terphenyl + 0.01% POPOP and 1.5% p-terphenyl + 0.01% DBP. The mean light-attenuation lengths are 180 cm and 260 cm, respectively, for strips with POPOP and DBP. The emittances of the polystyrene scintillators with DBP and POPOP additives have a ratio of 0.8:1.0 as recorded by an FEU-110 photomultiplier. 2 refs., 1 fig., 2 tabs

  9. Wide Strip Casting Technology of Magnesium Alloys

    Science.gov (United States)

    Park, W.-J.; Kim, J. J.; Kim, I. J.; Choo, D.

    Extensive investigations relating to the production of high performance and low cost magnesium sheet by strip casting have been performed for the application to automotive parts and electronic devices. Research on magnesium sheet production technology started in 2004 by Research Institute of Industrial Science and Technology (RIST) with support of Pohang Iron and Steel Company (POSCO). POSCO has completed the world's first plant to manufacture magnesium coil. Another big project in order to develop wide strip casting technology for the automotive applications of magnesium sheets was started in succession.

  10. Asset Stripping in a Mature Market Economy

    DEFF Research Database (Denmark)

    Klarskov Jeppesen, Kim; Møller, Ulrik Gorm

    2011-01-01

    Purpose – The purpose of this paper is to document a Danish fraud scheme, in which a large number of limited companies were stripped of their assets leaving them with nothing but tax debt, eventually causing the Danish Tax and Customs Administration to lose large sums. Furthermore, the purpose...... indicates that asset stripping may take place in mature market economies to the extent that perpetrators are able to circumvent the corporate governance system by giving lawyers, public accountants and banks incentives to act less critically towards dubious business transactions. Research limitations...

  11. In situ DRIFTS study of O{sub 3} adsorption on CaO, γ-Al{sub 2}O{sub 3}, CuO, α-Fe{sub 2}O{sub 3} and ZnO at room temperature for the catalytic ozonation of cinnamaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jianfeng; Su, Tongming; Jiang, Yuexiu; Xie, Xinling [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Qin, Zuzeng, E-mail: qinzuzeng@gmail.com [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Ji, Hongbing, E-mail: jihb@mail.sysu.edu.cn [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); School of Chemistry, Sun Yat-sen University, Guangzhou 510275 (China)

    2017-08-01

    Highlights: • In situ DRIFTS study of O{sub 3} adsorption on metal oxides at room temperature. • Using acidic probe molecules (DRIFTS) characterization of surface basicity. • Correlation between basic strength of metal oxides and O{sub 3} adsorption. • Study on the competitive adsorption of O{sub 3} and CO{sub 2}. • DRIFTS study of cinnamaldehyde ozonation and benzaldehyde excessive oxidation. - Abstract: In situ DRIFTS were conducted to identify adsorbed ozone and/or adsorbed oxygen species on CaO, ZnO, γ-Al{sub 2}O{sub 3}, CuO and α-Fe{sub 2}O{sub 3} surfaces at room temperature. Samples were characterized by means of TG, XRD, N{sub 2} adsorption–desorption, pyridine-IR, nitrobenzene-IR, chloroform-IR, and CO{sub 2}-TPD. Pyridine-DRIFTS measurements evidence two kinds of acid sites in all the samples. Nitrobenzene, chloroform-DRIFTS, and CO{sub 2}-TPD reveal that there are large amounts of medium-strength base sites on all the metal oxides, and only CaO, ZnO, and γ-Al{sub 2}O{sub 3} have strong base sites. And the benzaldehyde selectivity was increased in the same order of the alkalinity of the metal oxides. With weaker sites, ozone molecules form coordinative complexes bound via the terminal oxygen atom, observed by vibrational frequencies at 2095–2122 and 1026–1054 cm{sup −1}. The formation of ozonide O{sub 3}{sup −} at 790 cm{sup −1}, atomic oxygen at 1317 cm{sup −1}, and superoxide O{sub 2}{sup −} at 1124 cm{sup −1} was detected; these species are believed to be intermediates of O{sub 3} decomposition on strong acid/base sites. The adsorption of ozone on metal oxides is a weak adsorption, and other gases, such as CO{sub 2}, will compete with O{sub 3} adsorption. The mechanism of cinnamaldehyde ozonation at room temperature over CaO shows that cinnamaldehyde can not only be oxidized into cinnamic acid, but also be further oxidized into benzaldehyde, benzoic acid, maleic anhydride, and ultimately mineralized to CO{sub 2} in the

  12. Enhanced catalytic behavior of Ni alloys in steam methane reforming

    Science.gov (United States)

    Yoon, Yeongpil; Kim, Hanmi; Lee, Jaichan

    2017-08-01

    The dissociation process of methane on Ni and Ni alloys are investigated by density functional theory (DFT) in terms of catalytic efficiency and carbon deposition. Examining the dissociation to CH3, CH2, CH, C, and H is not sufficient to properly predict the catalytic efficiency and carbon deposition, and further investigation of the CO gas-evolving reaction is required to completely understand methane dissociation in steam. The location of alloying element in Ni alloy needed be addressed from the results of ab-inito molecular dynamics (MD). The reaction pathway of methane dissociation associated with CO gas evolution is traced by performing first-principles calculations of the adsorption and activation energies of each dissociation step. During the dissociation process, two alternative reaction steps producing adsorbed C and H or adsorbed CO are critically important in determining coking inhibition as well as H2 gas evolution (i.e., the catalytic efficiency). The theoretical calculations presented here suggest that alloying Ni with Ru is an effective way to reduce carbon deposition and enhance the catalytic efficiency of H2 fueling in solid oxide fuel cells (SOFCs).

  13. Catalytic activity of lanthanum oxide for the reduction of cyclohexanone

    International Nuclear Information System (INIS)

    Sugunan, S.; Sherly, K.B.

    1994-01-01

    Lanthanum oxides, La 2 O 3 has been found to be an effective catalyst for the liquid phase reduction of cyclohexanone. The catalytic activities of La 2 O 3 activated at 300, 500 and 800 degC and its mixed oxides with alumina for the reduction of cylcohexanone with 2-propanol have been determined and the data parallel that of the electron donating properties of the catalysts. The electron donating properties of the catalysts have been determined from the adsorption of electron acceptors of different electron affinities on the surface of these oxides. (author). 15 refs., 2 figs., 1 tab

  14. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is ...

  15. Investigation of Mercury Reduction in Gold Stripping Process at Elevated Temperature

    Science.gov (United States)

    Pramudya, Irawan

    Mercury is present in many gold ores. By processing these ores, there is a potential of emitting mercury to the environment. Carbon regeneration kiln stacks have been observed as one of the primary source of mercury emission into the atmosphere. Before it is recycled back into the carbon in leach (CIL) or carbon in columns (CIC), carbon used in the gold extraction process needs to be reactivated thermally. Emission of mercury can be minimized by keeping the mercury left in the carbon low before it goes to the carbon regeneration kiln stacks. The objective of this study is establishing the optimum elution conditions of mercury cyanide from loaded carbon (which includes the eluent, concentration, temperature and elution time) with respect to gold stripping. Several methods such as acid washing (UNR-100, HCl or ethanol/UNR-100) were investigated prior to the stripping process. Furthermore, conventional pressurized Zadra and modified Zadra were also studied with regards to mercury concentration in the solution and vapor state as well as maximizing the gold stripping from industrial loaded carbon. 7% UNR-100 acid washing of loaded carbon at 80°C was able to wash out approximately 90% of mercury while maintaining the gold adsorption on the carbon (selective washing). The addition of alcohol in the UNR-100 acid washing solution was able to enhance mercury washing from 90% to 97%. Furthermore, mercury stripping using conventional pressurized (cyanide-alkaline) Zadra was best performed at 80°C (minimal amount of mercury reduced and volatilized) whereas using the same process only 40% of gold was stripped, which makes this process not viable. When alcohol was added to the stripping solution, at 80°C, 95% of gold was detected in the solution while keeping the reduction and volatilization of mercury low. The outcome of this study provides a better understanding of mercury behavior during the acid washing and stripping processes so that the risk of mercury exposure and

  16. Adsorption of uranium on halloysite

    International Nuclear Information System (INIS)

    Kilislioglu, A.; Bilgin, B.

    2002-01-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  17. Adsorption of uranium on halloysite

    Energy Technology Data Exchange (ETDEWEB)

    Kilislioglu, A.; Bilgin, B. [Istanbul Univ. (Turkey). Faculty of Engineering

    2002-07-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  18. Catalytic detritiation of water

    International Nuclear Information System (INIS)

    Rogers, M.L.; Lamberger, P.H.; Ellis, R.E.; Mills, T.K.

    1977-01-01

    A pilot-scale system has been used at Mound Laboratory to investigate the catalytic detritiation of water. A hydrophobic, precious metal catalyst is used to promote the exchange of tritium between liquid water and gaseous hydrogen at 60 0 C. Two columns are used, each 7.5 m long by 2.5 cm ID and packed with catalyst. Water flow is 5-10 cm 3 /min and countercurrent hydrogen flow is 9,000-12,000 cm 3 /min. The equipment, except for the columns, is housed in an inert atmosphere glovebox and is computer controlled. The hydrogen is obtained by electrolysis of a portion of the water stream. Enriched gaseous tritium is withdrawn for further enrichment. A description of the system is included along with an outline of its operation. Recent experimental data are discussed

  19. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  20. Butanol production from wood pulping hydrolysate in an integrated fermentation-gas stripping process.

    Science.gov (United States)

    Lu, Congcong; Dong, Jie; Yang, Shang-Tian

    2013-09-01

    Wood pulping hydrolysate (WPH) containing mainly xylose and glucose as a potential substrate for acetone-butanol-ethanol (ABE) fermentation was studied. Due to the inhibitors present in the hydrolysate, several dilution levels and detoxification treatments, including overliming, activated charcoal adsorption, and resin adsorption, were evaluated for their effectiveness in relieving the inhibition on fermentation. Detoxification using resin and evaporation was found to be the most effective method in reducing the toxicity of WPH. ABE production in batch fermentation by Clostridium beijerinckii increased 68%, from 6.73 g/L in the non-treated and non-diluted WPH to 11.35 g/L in the resin treated WPH. With gas stripping for in situ product removal, ABE production from WPH increased to 17.73 g/L, demonstrating that gas stripping was effective in alleviating butanol toxicity by selectively separating butanol from the fermentation broth, which greatly improved solvents production and sugar conversion in the fermentation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Linear sweep anodic stripping voltammetry: Determination of ...

    Indian Academy of Sciences (India)

    The aim of this work is to determine Cr(VI) in water resources by anodic stripping voltammetry using SPE-. AuNPs modified electrode .... surface area about 4 fold). 3.2 Optimization of Parameters ..... in water samples. The above system offers a.

  2. Physical distribution of oak strip flooring 1969

    Science.gov (United States)

    William C. Miller; William C. Miller

    1971-01-01

    As an aid to the marketing of oak strip flooring, a study was made of the distribution process for this product, from manufacture to consumer-where the flooring came from, where it went, how much was shipped, and who handled it.

  3. The Advantages of Lateral Tarsal Strip Procedure

    African Journals Online (AJOL)

    Generally in surgery, an ideal operation should be effective, cause minimal discomfort and morbidity, give an aesthetic result, and have a lasting effect.[4]. Lateral strip procedure (LSP) has those characteristics and it does restore normal lid function and give a rapid rehabilitation with few complications and excellent.

  4. Nuclear reactor spring strip grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Flora, B.S.

    1980-01-01

    An improved and novel grid spacer for maintaining the fuel rods of a nuclear reactor fuel assembly in substantially parallel array is described. The invention provides for spring strips to maintain the fuel elements in their desired orientation which have more positive alignment than previous types while allowing greater flexibility to counterbalance the effects of differential thermal expansion. (UK)

  5. Nanoscale Test Strips for Multiplexed Blood Analysis

    Science.gov (United States)

    Chan, Eugene

    2015-01-01

    A critical component of the DNA Medicine Institute's Reusable Handheld Electrolyte and Lab Technology for Humans (rHEALTH) sensor are nanoscale test strips, or nanostrips, that enable multiplexed blood analysis. Nanostrips are conceptually similar to the standard urinalysis test strip, but the strips are shrunk down a billionfold to the microscale. Each nanostrip can have several sensor pads that fluoresce in response to different targets in a sample. The strips carry identification tags that permit differentiation of a specific panel from hundreds of other nanostrip panels during a single measurement session. In Phase I of the project, the company fabricated, tested, and demonstrated functional parathyroid hormone and vitamin D nanostrips for bone metabolism, and thrombin aptamer and immunoglobulin G antibody nanostrips. In Phase II, numerous nanostrips were developed to address key space flight-based medical needs: assessment of bone metabolism, immune response, cardiac status, liver metabolism, and lipid profiles. This unique approach holds genuine promise for space-based portable biodiagnostics and for point-of-care (POC) health monitoring and diagnostics here on Earth.

  6. KRITIK SOSIAL DALAM KOMIK STRIP PAK BEI

    Directory of Open Access Journals (Sweden)

    Yudhi Novriansyah

    2016-08-01

    Full Text Available This research aimed to do interpret the marking which flange social criticism and know laboring ideology in story of Comic Strip Pak Bei. Research based on theory of structural semiotic according to Ferdinand De Saussure. Using analysis of Syntagmatic as first level of meaning to the text network and also picture, and analysis of Paradigmatic as second level of meaning or implicit meaning (connota-tion, myth, ideology Analysis done to six Comic choice edition of Strip Pak Bei period of November 2004 - Februari 2005 which tend to flange social criticism. At band of syntagmatic, result of research indicate that story theme lifted from social problems that happened in major society. The fact clear progressively when connected by Intertextual with information and texts which have preexisted. At band of Paradigmatic, social criticism tend to emerge dimly, is not transparent. Because of Comic Strip Pak Bei expand in the middle of Java cultural domination that developing myth of criticize as action menacing compatibility and orderliness of society. Story of Comic Strip Pak Bei also confirm dominant ideology in Java society culture, namely ideology of Patriarkhi and Feudalism which still go into effect until now. This prove ideology idea according to Louis Althusser which not again opposition between class, but have been owned and practiced by all social class.

  7. Polymer Inclusion Membranes with Strip Dispersion

    Directory of Open Access Journals (Sweden)

    Yueh-Hsien Li

    2017-06-01

    Full Text Available The present work investigated the permeation of indium ions through a polymer inclusion membrane (PIM, prepared with cellulose triacetate (CTA as the base polymer, tris(2-butoxyethyl phosphate (TBEP as the plasticizer and di-(2-ethylhexylphosphoric acid (D2EHPA as the extractant. With 5 M HCl aqueous solution as the strip solution, we observed an initial indium permeability of 2.4 × 10−4 m/min. However, the permeability decreases with time, dropping to about 3.4 × 10−5 m/min after 200 min of operation. Evidence was obtained showing that hydrolysis of CTA occurred, causing a dramatic decrease in the feed pH (protons transported from strip to feed solutions and a loss of extractant and plasticizer from the membrane, and then leading to the loss of indium permeability. To alleviate the problem of hydrolysis, we proposed an operation scheme called polymer inclusion membranes with strip dispersion: dispersing the strip solution in extractant-containing oil and then bringing the dispersion to contact with the polymer membrane. Since the strong acid was dispersed in oil, the membrane did not directly contact the strong acid at all times, and membrane hydrolysis was thus alleviated and the loss of indium permeability was effectively prevented. With the proposed scheme, a stable indium permeability of 2.5 × 10−4 m/min was obtained during the whole time period of the permeation experiment.

  8. Comic Strips to Accompany Science Museum Exhibits

    Science.gov (United States)

    Chung, Beom Sun; Park, Eun-mi; Kim, Sang-Hee; Cho, Sook-kyoung; Chung, Min Suk

    2016-01-01

    Science museums make the effort to create exhibits with amusing explanations. However, existing explanation signs with lengthy text are not appealing, and as such, visitors do not pay attention to them. In contrast, conspicuous comic strips composed of simple drawings and humors can attract science museum visitors. This study attempted to reveal…

  9. Ductility of reinforced concrete columns confined with stapled strips

    International Nuclear Information System (INIS)

    Tahir, M.F.; Khan, Q.U.Z.; Shabbir, F.; Sharif, M.B.; Ijaz, N.

    2015-01-01

    Response of three 150x150x450mm short reinforced concrete (RC) columns confined with different types of confining steel was investigated. Standard stirrups, strips and stapled strips, each having same cross-sectional area, were employed as confining steel around four comer column bars. Experimental work was aimed at probing into the affect of stapled strip confinement on post elastic behavior and ductility level under cyclic axial load. Ductility ratios, strength enhancement factor and core concrete strengths were compared to study the affect of confinement. Results indicate that strength enhancement in RC columns due to strip and stapled strip confinement was not remarkable as compared to stirrup confined column. It was found that as compared to stirrup confined column, stapled strip confinement enhanced the ductility of RC column by 183% and observed axial capacity of stapled strip confined columns was 41 % higher than the strip confined columns. (author)

  10. Strip reduction testing of lubricants developed during ENFORM project

    DEFF Research Database (Denmark)

    Gazvoda, S.; Andreasen, Jan Lasson; Olsson, David Dam

    Strip reduction testing of lubricants developed during ENFORM project. Experiments were conducted with the strip reduction test [1] in order to classify experimental lubricants, developed during concerned project. One reference lubricant was used during testing....

  11. Refuges, flower strips, biodiversity and agronomic interest.

    Science.gov (United States)

    Roy, Grégory; Wateau, Karine; Legrand, Mickaël; Oste, Sandrine

    2008-01-01

    Several arthropods are natural predators of pests, and they are able to reduce and control their population development. FREDON Nord Pas-de-Calais (Federation Regionate de Defense contre les Organismes Nuisibles = Regional Federation for Pest Control) has begun for a long time to form farmers to the recognition of beneficial arthropods and to show them their usefulness. These beneficial insects or arachnids are present everywhere, in orchards and even in fields which are areas relatively poor in biodiversity. Adults feed in the flower strips instead larvae and some adults feed on preys such as aphids or caterpillars. Most of the time, beneficial insects can regulate pest but sometimes, in agricultural area, they can't make it early enough and efficiently. Their action begin too late and there biodiversity and number are too low. It's possible to enhance their action by manipulating the ecological infrastructures, like sewing flower strips or installing refuges. Flower strips increase the density of natural enemies and make them be present earlier in the field in order to control pests. Refuges permit beneficial's to spend winter on the spot. So they're able to be active and to grow in number earlier. From 2004 to 2007, on the one hand, FREDON Nord Pas-de-Calais has developed a research program. Its purpose was to inventory practices and also tools and means available and to judge the advisability of using such or such beneficial refuge in orchards. On the second hand, it studied the impact in orchard of refuges on population of beneficial's and the difference there were between manufactured refuges and homemade refuges. Interesting prospects were obtained with some of them. Otherwise, since 2003, FREDON has studied flower strips influence on beneficial population and their impact on pest control. In cabbage fields, results of trials have shown that flower strips lead to a reduction of aphid number under acceptable economic level, up to 50 meters from flower strips

  12. Parallel superconducting strip-line detectors: reset behaviour in the single-strip switch regime

    International Nuclear Information System (INIS)

    Casaburi, A; Heath, R M; Tanner, M G; Hadfield, R H; Cristiano, R; Ejrnaes, M; Nappi, C

    2014-01-01

    Superconducting strip-line detectors (SSLDs) are an important emerging technology for the detection of single molecules in time-of-flight mass spectrometry (TOF-MS). We present an experimental investigation of a SSLD laid out in a parallel configuration, designed to address selected single strip-lines operating in the single-strip switch regime. Fast laser pulses were tightly focused onto the device, allowing controllable nucleation of a resistive region at a specific location and study of the subsequent device response dynamics. We observed that in this regime, although the strip-line returns to the superconducting state after triggering, no effective recovery of the bias current occurs, in qualitative agreement with a phenomenological circuit simulation that we performed. Moreover, from theoretical considerations and by looking at the experimental pulse amplitude distribution histogram, we have the first confirmation of the fact that the phenomenological London model governs the current redistribution in these large area devices also after detection events. (paper)

  13. Catalytic hot gas cleaning of gasification gas

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1997-12-31

    The aim of this work was to study the catalytic cleaning of gasification gas from tars and ammonia. In addition, factors influencing catalytic activity in industrial applications were studied, as well as the effects of different operation conditions and limits. Also the catalytic reactions of tar and ammonia with gasification gas components were studied. The activities of different catalyst materials were measured with laboratory-scale reactors fed by slip streams taken from updraft and fluid bed gasifiers. Carbonate rocks and nickel catalysts proved to be active tar decomposing catalysts. Ammonia decomposition was in turn facilitated by nickel catalysts and iron materials like iron sinter and iron dolomite. Temperatures over 850 deg C were required at 2000{sup -1} space velocity at ambient pressure to achieve almost complete conversions. During catalytic reactions H{sub 2} and CO were formed and H{sub 2}O was consumed in addition to decomposing hydrocarbons and ammonia. Equilibrium gas composition was almost achieved with nickel catalysts at 900 deg C. No deactivation by H{sub 2}S or carbon took place in these conditions. Catalyst blocking by particulates was avoided by using a monolith type of catalyst. The apparent first order kinetic parameters were determined for the most active materials. The activities of dolomite, nickel catalyst and reference materials were measured in different gas atmospheres using laboratory apparatus. This consisted of nitrogen carrier, toluene as tar model compound, ammonia and one of the components H{sub 2}, H{sub 2}O, CO, CO{sub 2}, CO{sub 2}+H{sub 2}O or CO+CO{sub 2}. Also synthetic gasification gas was used. With the dolomite and nickel catalyst the highest toluene decomposition rates were measured with CO{sub 2} and H{sub 2}O. In gasification gas, however, the rate was retarded due to inhibition by reaction products (CO, H{sub 2}, CO{sub 2}). Tar decomposition over dolomite was modelled by benzene reactions with CO{sub 2}, H

  14. Study the Z-Plane Strip Capacitance

    International Nuclear Information System (INIS)

    Parikh, H.; Swain, S.

    2005-01-01

    The BaBaR detector at the Stanford Linear Accelerator Center is currently undergoing an upgrade to improve its muon and neutral hadron detection system. The Resistive Plate Chambers (RPCs) that had been used till now have deteriorated in performance over the past few years and are being replaced by Limited Streamer Tube (LSTs). Each layer of the system consists of a set of up to 10 streamer tube modules which provide one coordinate (φ coordinate) and a single ''Z-plane'' which provides the Z coordinate of the hit. The large area Z-planes (up to 12m 2 ) are 1mm thick and contain 96 copper strips that detect the induced charge from avalanches created in the streamer tube wires. All the Z-planes needed for the upgrade have already been constructed, but only a third of the planes were installed last summer. After installing the 24 Z-planes last year, it was learned that 0.7% of the strips were dead when put inside the detector. This was mainly due to the delicate solder joint between the read-out cable and the strip, and since it is difficult to access or replace the Z-planes inside the detector, it is very important to perform various tests to make sure that the Z-planes will be efficient and effective in the long term. We measure the capacitance between the copper strips and the ground plane, and compare it to the theoretical value that we expect. Instead of measuring the capacitance channel by channel, which would be a very tedious job, we developed a more effective method of measuring the capacitance. Since all the Z-planes were built at SLAC, we also built a smaller 46 cm by 30 cm Z-plane with 12 strips just to see how they were constructed and to gain a better understanding about the solder joints

  15. Regenerative adsorption distillation system

    KAUST Repository

    Ng, Kim Choon

    2013-12-26

    There is provided a regenerative adsorption distillation system comprising a train of distillation effects in fluid communication with each other. The train of distillation effects comprises at least one intermediate effect between the first and last distillation effects of the train, each effect comprising a vessel and a condensing tube for flow of a fluid therein. The system further comprises a pair of adsorption-desorption beds in vapour communication with the last effect and at least one intermediate effect, wherein the beds contain an adsorbent that adsorbs vapour from the last effect and transmits desorbed vapour into at least one of the intermediate effect.

  16. Regenerative adsorption distillation system

    KAUST Repository

    Ng, Kim Choon; Thu, Kyaw; Amy, Gary; Chunggaze, Mohammed; Al-Ghasham, Tawfiq

    2013-01-01

    There is provided a regenerative adsorption distillation system comprising a train of distillation effects in fluid communication with each other. The train of distillation effects comprises at least one intermediate effect between the first and last distillation effects of the train, each effect comprising a vessel and a condensing tube for flow of a fluid therein. The system further comprises a pair of adsorption-desorption beds in vapour communication with the last effect and at least one intermediate effect, wherein the beds contain an adsorbent that adsorbs vapour from the last effect and transmits desorbed vapour into at least one of the intermediate effect.

  17. Advection endash diffusion past a strip. II. Oblique incidence

    International Nuclear Information System (INIS)

    Knessl, C.; Keller, J.B.

    1997-01-01

    Advection and diffusion of particles past an impenetrable strip is considered when the strip is oblique to the advection or drift velocity. The particle concentration p(x,y) is determined asymptotically for large values of vL/D, where v is the drift velocity, D is the diffusion coefficient, and 2L is the width of the strip. The results complement those of Part I, which treated a strip normal to the drift velocity. copyright 1997 American Institute of Physics

  18. Catalytic production of biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Theilgaard Madsen, A.

    2011-07-01

    The focus of this thesis is the catalytic production of diesel from biomass, especially emphasising catalytic conversion of waste vegetable oils and fats. In chapter 1 an introduction to biofuels and a review on different catalytic methods for diesel production from biomass is given. Two of these methods have been used industrially for a number of years already, namely the transesterification (and esterification) of oils and fats with methanol to form fatty acid methyl esters (FAME), and the hydrodeoxygenation (HDO) of fats and oils to form straight-chain alkanes. Other possible routes to diesel include upgrading and deoxygenation of pyrolysis oils or aqueous sludge wastes, condensations and reductions of sugars in aqueous phase (aqueous-phase reforming, APR) for monofunctional hydrocarbons, and gasification of any type of biomass followed by Fischer-Tropsch-synthesis for alkane biofuels. These methods have not yet been industrialised, but may be more promising due to the larger abundance of their potential feedstocks, especially waste feedstocks. Chapter 2 deals with formation of FAME from waste fats and oils. A range of acidic catalysts were tested in a model fat mixture of methanol, lauric acid and trioctanoin. Sulphonic acid-functionalised ionic liquids showed extremely fast convertion of lauric acid to methyl laurate, and trioctanoate was converted to methyl octanoate within 24 h. A catalyst based on a sulphonated carbon-matrix made by pyrolysing (or carbonising) carbohydrates, so-called sulphonated pyrolysed sucrose (SPS), was optimised further. No systematic dependency on pyrolysis and sulphonation conditions could be obtained, however, with respect to esterification activity, but high activity was obtained in the model fat mixture. SPS impregnated on opel-cell Al{sub 2}O{sub 3} and microporous SiO{sub 2} (ISPS) was much less active in the esterification than the original SPS powder due to low loading and thereby low number of strongly acidic sites on the

  19. Testbeam evaluation of silicon strip modules for ATLAS Phase - II Strip Tracker Upgrade

    CERN Document Server

    Blue, Andrew; The ATLAS collaboration; Ai, Xiaocong; Allport, Phillip; Arling, Jan-Hendrik; Atkin, Ryan Justin; Bruni, Lucrezia Stella; Carli, Ina; Casse, Gianluigi; Chen, Liejian; Chisholm, Andrew; Cormier, Kyle James Read; Cunningham, William Reilly; Dervan, Paul; Diez Cornell, Sergio; Dolezal, Zdenek; Dopke, Jens; Dreyer, Etienne; Dreyling-Eschweiler, Jan Linus Roderik; Escobar, Carlos; Fabiani, Veronica; Fadeyev, Vitaliy; Fernandez Tejero, Javier; Fleta Corral, Maria Celeste; Gallop, Bruce; Garcia-Argos, Carlos; Greenall, Ashley; Gregor, Ingrid-Maria; Greig, Graham George; Guescini, Francesco; Hara, Kazuhiko; Hauser, Marc Manuel; Huang, Yanping; Hunter, Robert Francis Holub; Keller, John; Klein, Christoph; Kodys, Peter; Koffas, Thomas; Kotek, Zdenek; Kroll, Jiri; Kuehn, Susanne; Lee, Steven Juhyung; Liu, Yi; Lohwasser, Kristin; Meszarosova, Lucia; Mikestikova, Marcela; Mi\\~nano Moya, Mercedes; Mori, Riccardo; Moser, Brian; Nikolopoulos, Konstantinos; Peschke, Richard; Pezzullo, Giuseppe; Phillips, Peter William; Poley, Anne-luise; Queitsch-Maitland, Michaela; Ravotti, Federico; Rodriguez Rodriguez, Daniel

    2018-01-01

    The planned HL-LHC (High Luminosity LHC) is being designed to maximise the physics potential of the LHC with 10 years of operation at instantaneous luminosities of \\mbox{$7.5\\times10^{34}\\;\\mathrm{cm}^{-2}\\mathrm{s}^{-1}$}. A consequence of this increased luminosity is the expected radiation damage requiring the tracking detectors to withstand hadron equivalences to over $1x10^{15}$ 1 MeV neutron equivalent per $cm^{2}$ in the ATLAS Strips system. The silicon strip tracker exploits the concept of modularity. Fast readout electronics, deploying 130nm CMOS front-end electronics are glued on top of a silicon sensor to make a module. The radiation hard n-in-p micro-strip sensors used have been developed by the ATLAS ITk Strip Sensor collaboration and produced by Hamamatsu Photonics. A series of tests were performed at the DESY-II test beam facility to investigate the detailed performance of a strip module with both 2.5cm and 5cm length strips before irradiation. The DURANTA telescope was used to obtain a pointing...

  20. 7 CFR 29.6128 - Straight Stripped (X Group).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Straight Stripped (X Group). 29.6128 Section 29.6128... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.6128 Straight Stripped (X Group). This group consists of..., and tolerances X1 Fine Quality Straight Stripped. Heavy, ripe, firm, semielastic, normal strength and...

  1. Physical adsorption and molecular dynamics

    International Nuclear Information System (INIS)

    Cohan, N.V.

    1981-01-01

    Some aspects of noble gases adsorption (except He) on graphite substracts are reviewed. Experimental results from this adsorption are analyzed and compared with molecular dynamics calculations. (L.C.) [pt

  2. Sulfate adsorption on goethite

    Energy Technology Data Exchange (ETDEWEB)

    Rietra, R P.J.J.; Hiemstra, T; Riemsdijk, W.H. van

    1999-10-15

    Recent spectroscopic work has suggested that only one surface species of sulfate is dominant on hematite. Sulfate is therefore a very suitable anion to test and develop adsorption models for variable charge minerals. The authors have studied sulfate adsorption on goethite covering a large range of sulfate concentrations, surface coverages, pH values, and electrolyte concentrations. Four different techniques were used to cover the entire range of conditions. For characterization at low sulfate concentrations, below the detection limit of sulfate with ICP-AES, the authors used proton-sulfate titrations at constant pH. Adsorption isotherms were studied for the intermediate sulfate concentration range. Acid-base titrations in sodium sulfate and electromobility were used for high sulfate concentrations. All the data can be modeled with one adsorbed species if it is assumed that the charge of adsorbed sulfate is spatially distributed in the interface. The charge distribution of sulfate follows directly from modeling the proton-sulfate adsorption stoichoimemtry sine this stoichiometry is independent of the intrinsic affinity constant of sulfate. The charge distribution can be related to the structure of the surface complex by use of the Pauling bond valence concept and is in accordance with the microscopic structure found by spectroscopy. The intrinsic affinity constant follows from the other measurements. Modeling of the proton-ion stoichoimetry with the commonly used 2-pK models, where adsorbed ions are treated as point charges, is possible only if at least two surface species for sulfate are used.

  3. Catalytic cracking of lignites

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, M.; Nowak, S.; Naegler, T.; Zimmermann, J. [Hochschule Merseburg (Germany); Welscher, J.; Schwieger, W. [Erlangen-Nuernberg Univ. (Germany); Hahn, T. [Halle-Wittenberg Univ., Halle (Germany)

    2013-11-01

    A most important factor for the chemical industry is the availability of cheap raw materials. As the oil price of crude oil is rising alternative feedstocks like coal are coming into focus. This work, the catalytic cracking of lignite is part of the alliance ibi (innovative Braunkohlenintegration) to use lignite as a raw material to produce chemicals. With this new one step process without an input of external hydrogen, mostly propylene, butenes and aromatics and char are formed. The product yield depends on manifold process parameters. The use of acid catalysts (zeolites like MFI) shows the highest amount of the desired products. Hydrogen rich lignites with a molar H/C ratio of > 1 are to be favoured. Due to primary cracking and secondary reactions the ratio between catalyst and lignite, temperature and residence time are the most important parameter to control the product distribution. Experiments at 500 C in a discontinuous rotary kiln reactor show yields up to 32 wt-% of hydrocarbons per lignite (maf - moisture and ash free) and 43 wt-% char, which can be gasified. Particularly, the yields of propylene and butenes as main products can be enhanced four times to about 8 wt-% by the use of catalysts while the tar yield decreases. In order to develop this innovative process catalyst systems fixed on beads were developed for an easy separation and regeneration of the used catalyst from the formed char. (orig.)

  4. Catalytic reduction of NO by methane using a Pt/C/polybenzimidazole/Pt/C fuel cell

    DEFF Research Database (Denmark)

    Petrushina, Irina; Cleemann, Lars Nilausen; Refshauge, Rasmus

    2007-01-01

    with participation of H+ or electrochemically produced hydrogen. When added, methane partially suppresses the electrochemical reduction of NO. Methane outlet concentration monitoring has shown the CH4 participation in the chemical catalytic reduction, i.e., methane co-adsorption with NO inhibited the electrochemical...... NO reduction and introduced a dominant chemical path of the NO reduction. The products of the NO reduction with methane were N2, C2H4, and water. The catalytic NO reduction by methane was promoted when the catalyst was negatively polarized (−0.2 V). Repeated negative polarization of the catalyst increased...

  5. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    126, No. 2, March 2014, pp. 341–351. c Indian Academy of Sciences. ... enhancement was realized by catalyst design, appropriate choice of reactor, better injection and .... Gas–liquid and liquid–solid transport processes in catalytic reactors.5.

  6. Characterization of deactivated catalytic cracking catalyst and evaluation as absorbent material

    International Nuclear Information System (INIS)

    Valt, R.B.G.; Kaminari, N.M.S.; Cordeiro, B.; Ponte, M.J.J.S.; Ponte, H.A.

    2010-01-01

    One of the main uses of catalysts in the petroleum industry is in step catalytic cracking, which after use and regeneration cycles generates large quantities of waste material. In this research the deactivated FCC catalyst was characterized before and after the electrokinetic remediation process, in order to assess the change of its structure and possible adsorptive capacity. Analyses of X-Ray Fluorescence Spectroscopy, Scanning Electron Microscopy and BET surface area measurement were performed. The analysis showed no structural change due to the process employed and that electrokinetic remediation has recovered 42% of adsorption capacity of the material, by removing about 89% of heavy metals adhered initially in the catalyst surface. (author)

  7. Characterization of gallium-containing zeolites for catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Sanchez, M.

    2003-12-08

    The present study considers the synthesis, characterization, and catalytic evaluation of extra-framework gallium-containing zeolites. We focus on modification of zeolites by chemical vapor deposition of trimethylgallium on HZSM-5 and Mordenite zeolites. Chapter 2 is dedicated to the chemisorption and stability of TMG on HZSM-5 and HMOR zeolites. The effect of silylation is also addressed. Some theoretical calculations are also shown in this study to support part of the experimental results. In Chapter 3, the effect of oxidation and reduction treatments on these catalysts is investigated by FTIR, ICP and multinuclei NMR. In Chapter 4, the oxidation state and Ga coordination obtained during and after thermal treatment with H2 and O2 is analysed by X-ray adsorption spectroscopy (XANES and EXAFS) and IR analysis of CO adsorption. These results allow a better understanding of the catalytic behaviour of Ga-containing zeolites catalyst. Chapter 5 consists of two parts: one discusses the H2 activation over Ga/HZSM5 and Ga/MOR catalysts by H2/D2 isotopic exchange reaction, and the second part deals with the aromatization of n-heptane over the same catalysts.

  8. Interplay of complete wetting, critical adsorption, and capillary condensation.

    Science.gov (United States)

    Drzewiński, A; Maciołek, A; Barasiński, A; Dietrich, S

    2009-04-01

    The excess adsorption Gamma in two-dimensional Ising strips (infinityxL), subject to identical boundary fields at both one-dimensional surfaces decaying in the orthogonal direction j as -h1j(-p), is studied for various values of p and along various thermodynamic paths below the bulk critical point by means of the density-matrix renormalization-group method. The crossover behavior between the complete-wetting and critical-adsorption regimes, occurring in semi-infinite systems, is strongly influenced by confinement effects. Along isotherms T=const the asymptotic power-law dependences on the external bulk field, which characterize these two regimes, are pre-empted by capillary condensation. Along the pseudo-first-order phase-coexistence line of the strips, which varies with temperature, we find a broad crossover regime in which both the thickness of the wetting film and Gamma increase as functions of the reduced temperature tau but do not follow any power law. Above the wetting temperature the order-parameter profiles are not slablike but exhibit wide interfacial variations and pronounced tails.

  9. The extent of the stop coannihilation strip

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, John [King' s College London, Theoretical Particle Physics and Cosmology Group, Department of Physics, London (United Kingdom); CERN, Theory Division, Geneva 23 (Switzerland); Olive, Keith A. [University of Minnesota, School of Physics and Astronomy, Minneapolis, MN (United States); University of Minnesota, William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, Minneapolis, MN (United States); Zheng, Jiaming [University of Minnesota, School of Physics and Astronomy, Minneapolis, MN (United States)

    2014-07-15

    Many supersymmetric models such as the constrained minimal supersymmetric extension of the Standard Model (CMSSM) feature a strip in parameter space where the lightest neutralino χ is identified as the lightest supersymmetric particle, the lighter stop squark t{sub 1} is the next-to-lightest supersymmetric particle (NLSP), and the relic χ cold darkmatter density is brought into the range allowed by astrophysics and cosmology by coannihilation with the lighter stop squark t{sub 1} NLSP. We calculate the stop coannihilation strip in the CMSSM, incorporating Sommerfeld enhancement effects, and we explore the relevant phenomenological constraints and phenomenological signatures. In particular, we show that the t{sub 1} may weigh several TeV, and its lifetime may be in the nanosecond range, features that are more general than the specific CMSSM scenarios that we study in this paper. (orig.)

  10. Strip-till seeder for sugar beets

    Directory of Open Access Journals (Sweden)

    Peter Schulze Lammers

    2014-06-01

    Full Text Available Strip-till save costs by reducing tillage on the area of sugar beet rows only. The seeding system is characterized by a deep loosening of soil with a tine combined with a share and by following tools generating fine-grained soil as seed bed. In cooperation with the Kverneland company group Soest/Germany a strip tiller combined with precision seeder was designed and tested in field experiments. Tilling and seeding was performed in one path on fields with straw and mustard mulch. Even the plant development was slower as compared to conventional sawn sugar beets the yield was on equivalent level. Further field experiments are planned to attest constant yield, cost and energy efficiency of the seeding system.

  11. Dual deflectable beam strip engine development.

    Science.gov (United States)

    Dulgeroff, C. R.; Zuccaro, D. E.; Kami, S.; Schnelker, D. E.; Ward, J. W.

    1972-01-01

    This paper describes a dual beam thruster that has been designed, constructed, and tested. The system is suitable for two-axes attitude control and is comprised of two orthogonal strips, each capable of producing 0.30 mlb thrust and beam deflections of more than plus or minus 20 deg. The nominal specific impulse for the thruster is 5000 sec, and the thrust level from each strip can be varied from 0 to 100%. Neutralizer filaments that were developed and life tested over 2000 hours producing more than 40 mA of electron emission per watt of input power are also discussed. The system power required for clean ionizers is approximately 200 W.

  12. L-strip proximity fed ga

    Directory of Open Access Journals (Sweden)

    Ashish Singh

    2014-03-01

    Full Text Available In this article, the analysis of dualband L-strip fed compact semi-circular disk microstrip patch antenna has been presented using circuit theory concept. The antenna parameters such as return loss, VSWR and radiation pattern are calculated. The effect of geometric dimensions of the proposed antenna such as length of vertical and horizontal portion of L-strip is investigated. It is found that antenna resonate at two distinct modes i.e. 1.3 GHz and 6.13 GHz for lower and upper resonance frequencies respectively. The bandwidth of the proposed antenna at lower resonance frequency is 6.61% (simulated and 10.64% (theoretical whereas at upper resonance frequency, it is 6.02% (simulated and 9.06 % (theoretical. The theoretical results are compared with IE3D simulation results as well as experimental results and they are in close agreement.

  13. Nuclear reactor spring strip grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Flora, B.S.

    1980-01-01

    An improved and novel grid spacer was developed for use in nuclear reactor fuel assemblies. It is comprised of a series of intersecting support strips and a peripheral support band attached to the ends of the support strips. Each of the openings into which the fuel element is inserted has a number of protruding dimples and springs extending in different directions. The dimples coact with the springs to secure the fuel rods in the openings. Compared with previous designs, this design gives more positive alignment of the support stips while allowing greater flexibility to counterbalance the effects of thermal expansion. The springs are arranged in alternating directions so that the reaction forces tend to counterbalance each other, which in turn minimizes the reaction loads on the supporting structure. (D.N.)

  14. Electron capture by highly stripped ions

    International Nuclear Information System (INIS)

    Greenland, P.T.

    1981-06-01

    This review describes theories of electron capture suitable for the description of rearrangement collisions between atomic hydrogen and completely stripped projectiles with charge greater than unity. The region of impact velocity considered lies between 0.05 and 3 au, which is of technological importance in fusion power devices. The semiclassical, impact parameter formalism is discussed and the use of atomic expansions at medium impact velocity is described. Experimental results for both completely and partially stripped projectiles are reviewed. The use of a molecular basis at low energy, and the role of pseudocrossings peculiar to the two centre Coulomb interaction are described. Finally, purely classical techniques, in which the electron wavefunction is represented by an ensemble of Kepler orbits are considered. The review was completed in February 1981. (author)

  15. Continuous liquid sheet generator for ion stripping

    International Nuclear Information System (INIS)

    Gavin, B.; Batson, P.; Leemann, B.; Rude, B.

    1984-10-01

    Many of the technical problems of generating a large thin liquid sheet from 0.02 to 0.20 μm thick (3 to 40 μgm/cm 2 ) have been solved. It is shown that this perennial sheet is stable and consonant in dimension. Several ion beam species from the SuperHILAC have been used for evaluation; at 0.11 MeV/n. In one of three modes this sheet serves as an equivalent substitute for a carbon foil. The second mode is characterized by a solid-like charge state distribution but with a varying fraction of unstripped ions. The third mode gives stripping performance akin to a vapor stripping medium. 9 references, 7 figures

  16. Large strip RPCs for the LEPS2 TOF system

    Energy Technology Data Exchange (ETDEWEB)

    Tomida, N., E-mail: natsuki@scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Niiyama, M. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Ohnishi, H. [RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198 (Japan); Tran, N. [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Hsieh, C.-Y.; Chu, M.-L.; Chang, W.-C. [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Chen, J.-Y. [National Synchrotron Radiation Research Center (NSRRC), Hsinchu 30076, Taiwan (China)

    2014-12-01

    High time-resolution resistive plate chambers (RPCs) with large-size readout strips are developed for the time-of-flight (TOF) detector system of the LEPS2 experiment at SPring-8. The experimental requirement is a 50-ps time resolution for a strip size larger than 100 cm{sup 2}/channel. We are able to achieve 50-ps time resolutions with 2.5×100 cm{sup 2} strips by directly connecting the amplifiers to strips. With the same time resolution, the number of front-end electronics (FEE) is also reduced by signal addition. - Highlights: • Find a way to achieve a good time resolution with a large strip RPC. • 2.5 cm narrow strips have better resolutions than 5.0 cm ones. • The 0.5 mm narrow strip interval shows flat time resolutions between strips. • FEEs directly connected to strips make the signal reflection at the strip edge small. • A time resolution of 50 ps was achieved with 2.5 cm×100 cm strips.

  17. Moving strip technique of electron beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, Kishio; Wakasa, Hiroyuki; Oguri, Nobuhiro; Kitayama, Takuichi; Nakagiri, Yoshitada; Mikami, Yasutaka; Hashimoto, Keiji; Hiraki, Yoshio; Aono, Kaname

    1984-12-01

    The fieldsize in electron beam therapy is determined by the cone size. In case of skin metastasis of a malignant tumor and so on, which need a large field size and whose area is much larger than the size of the cone, a large field size is usually produced by dividing the portals. However, the dose distribution at the border of the field becomes unequal, and hot and cold dose areas are produced according to the distance between portals. We tried the strip field technique in a large field along the long axis of the body in order to flatten the dose of the border employing the moving strip used for whole abdominal irradiation in ovarian cancer. We set the film in Mix-DP and used the strip field technique with 2.5cm steps. We discussed the relationship between the interval (distance between portals) and the flattening of the dose within the field. Skin movement due to breathing and influences on the flattening of the dose were considered. The proper flatness was obtained at depths of 0,1,2, and 3cm by setting the interval at 0.5cm. When skin movement was produced by breathing in +-1.5mm, the proper flaness was obtained also at a 0.5-cm interval. It seems that smoothing is increased by breathing. An ''electron beam moving strip'' with a 2.5-cm step and 0.5-cm interval was clinically effective in the treatment of patients with skin metastasis of colon cancer. (author).

  18. Ram pressure stripping of tilted galaxies

    Czech Academy of Sciences Publication Activity Database

    Jáchym, Pavel; Köppen, J.; Palouš, Jan; Combes, F.

    2009-01-01

    Roč. 500, č. 2 (2009), s. 693-703 ISSN 0004-6361 R&D Projects: GA MŠk(CZ) LC06014; GA ČR GP205/08/P556 Institutional research plan: CEZ:AV0Z10030501 Keywords : interstellar medium * clusters of galaxies * gas stripping Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.179, year: 2009

  19. Cathode readout with stripped resistive drift tubes

    International Nuclear Information System (INIS)

    Bychkov, V.N.; Kekelidze, G.D.; Novikov, E.A.; Peshekhonov, V.D.; Shafranov, M.D.; Zhiltsov, V.E.

    1995-01-01

    A straw tube drift chamber prototype has been constructed and tested. The straw tube material is mylar film covered with a carbon layer with a resistivity of 0.5, 30 and 70 kΩ/□. Both the anode wire and the cathode strip signals were detected to study the behaviour of the chamber in the presence of X-ray ionization. The construction and the results of the study are presented. (orig.)

  20. Cathode readout with stripped resistive drift tubes

    Science.gov (United States)

    Bychkov, V. N.; Kekelidze, G. D.; Novikov, E. A.; Peshekhonov, V. D.; Shafranov, M. D.; Zhiltsov, V. E.

    1995-12-01

    A straw tube drift chamber prototype has been constructed and tested. The straw tube material is mylar film covered with a carbon layer with a resistivity of 0.5, 30 and 70 kΩ/□. Both the anode wire and the cathode strip signals were detected to study the behaviour of the chamber in the presence of X-ray ionization. The construction and the results of the study are presented.

  1. A STUDY ON ADSORPTION AND DESORPTION BEHAVIORS OF 14C FROM A MIXED BED RESIN

    Directory of Open Access Journals (Sweden)

    SEUNG-CHUL PARK

    2014-12-01

    Full Text Available Spent resin waste containing a high concentration of 14C radionuclide cannot be disposed of directly. A fundamental study on selective 14C stripping, especially from the IRN-150 mixed bed resin, was carried out. In single ion-exchange equilibrium isotherm experiments, the ion adsorption capacity of the fresh resin for non-radioactive HCO3− ion, as the chemical form of 14C, was evaluated as 11mg-C/g-resin. Adsorption affinity of anions to the resin was derived in order of NO3− > HCO3− ≥ H2PO4−. Thus the competitive adsorption affinity of NO3− ion in binary systems appeared far higher than that of HCO3− or H2PO4−, and the selective desorption of HCO3− from the resin was very effective. On one hand, the affinity of Co2+ and Cs+ for the resin remained relatively higher than that of other cations in the same stripping solution. Desorption of Cs+ was minimized when the summation of the metal ions in the spent resin and the other cations in solution was near saturation and the pH value was maintained above 4.5. Among the various solutions tested, from the view-point of the simple second waste process, NH4H2PO4 solution was preferable for the stripping of 14C from the spent resin.

  2. Nitrogen removal from wastewater by a catalytic oxidation method.

    Science.gov (United States)

    Huang, T L; Macinnes, J M; Cliffe, K R

    2001-06-01

    The ammonia-containing waste produced in industries is usually characterized by high concentration and high temperature, and is not treatable by biological methods directly. In this study, a hydrophobic Pt/SDB catalyst was first used in a trickle-bed reactor to remove ammonia from wastewater. In the reactor, both stripping and catalytic oxidation occur simultaneously. It was found that higher temperature and higher oxygen partial pressure enhanced the ammonia removal. A reaction pathway, which involves oxidizing ammonia to nitric oxide, which then further reacts with ammonia to produce nitrogen and water, was confirmed. Small amounts of by-products, nitrites and nitrates were also detected in the resultant reaction solution. These compounds came from the absorption of nitrogen oxides. Both the minimum NO2- selectivity and maximum ammonia removal were achieved when the resultant pH of treated water was near 7.5 for a feed of unbuffered ammonia solution.

  3. Multiple Electron Stripping of Heavy Ion Beams

    International Nuclear Information System (INIS)

    Mueller, D.; Grisham, L.; Kaganovich, I.; Watson, R. L.; Horvat, V.; Zaharakis, K. E.; Peng, Y.

    2002-01-01

    One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 Mev/amu with charge state 1 currently do not exist. Hence, the stripping cross-sections used to model the performance of heavy ion fusion driver beams have, up to now, been based upon theoretical calculations. We have investigated experimentally the stripping of 3.4 Mev/amu Kr 7+ and Xe +11 in N2; 10.2 MeV/amu Ar +6 in He, N2, Ar and Xe; 19 MeV/amu Ar +8 in He, N2, Ar and Xe; 30 MeV He 1 + in He, N2, Ar and Xe; and 38 MeV/amu N +6 in He, N2, Ar and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters

  4. Deuteron stripping reactions with Tabakin potential

    International Nuclear Information System (INIS)

    Osman, A.

    1976-05-01

    Deuteron stripping reactions are considered. Due to the strong repulsion between nucleons at very short distances, we have investigated the nuclear short-range correlations. The neutron proton nuclear potential in the deuteron is taken as a short-range repulsive core surrounded by a long-range attractive potential. The neutron-proton potential is taken as the Tabakin separable potential to take into account the short-range correlations. The differential cross-sections for deuteron stripping reactions have been calculated in two different cases by taking Yamaguchi or Breit et al type parameters for the Tabakin potential used. The angular distributions for different (d,p) stripping reactions on the different target nuclei 28 Si, 32 , 34 S, 36 Ar, 40 , 48 Ca, 50 , 52 , 54 Cr have been calculated using the DWBA calculations. Our present theoretical calculations for the angular distributions of the different reactions cosidered have been fitted to the experimental data, where good agreement is obtained. The extracted spectroscopic factors from the present work are found to be more reliable

  5. The Argonne silicon strip-detector array

    Energy Technology Data Exchange (ETDEWEB)

    Wuosmaa, A H; Back, B B; Betts, R R; Freer, M; Gehring, J; Glagola, B G; Happ, Th; Henderson, D J; Wilt, P [Argonne National Lab., IL (United States); Bearden, I G [Purdue Univ., Lafayette, IN (United States). Dept. of Physics

    1992-08-01

    Many nuclear physics experiments require the ability to analyze events in which large numbers of charged particles are detected and identified simultaneously, with good resolution and high efficiency, either alone, or in coincidence with gamma rays. The authors have constructed a compact large-area detector array to measure these processes efficiently and with excellent energy resolution. The array consists of four double-sided silicon strip detectors, each 5x5 cm{sup 2} in area, with front and back sides divided into 16 strips. To exploit the capability of the device fully, a system to read each strip-detector segment has been designed and constructed, based around a custom-built multi-channel preamplifier. The remainder of the system consists of high-density CAMAC modules, including multi-channel discriminators, charge-sensing analog-to-digital converters, and time-to-digital converters. The array`s performance has been evaluated using alpha-particle sources, and in a number of experiments conducted at Argonne and elsewhere. Energy resolutions of {Delta}E {approx} 20-30 keV have been observed for 5 to 8 MeV alpha particles, as well as time resolutions {Delta}T {<=} 500 ps. 4 figs.

  6. CLOSED-LOOP STRIPPING ANALYSIS (CLSA) OF ...

    Science.gov (United States)

    Synthetic musk compounds have been found in surface water, fish tissues, and human breast milk. Current techniques for separating these compounds from fish tissues require tedious sample clean-upprocedures A simple method for the deterrnination of these compounds in fish tissues has been developed. Closed-loop stripping of saponified fish tissues in a I -L Wheaton purge-and-trap vessel is used to strip compounds with high vapor pressures such as synthetic musks from the matrix onto a solid sorbent (Abselut Nexus). This technique is useful for screening biological tissues that contain lipids for musk compounds. Analytes are desorbed from the sorbent trap sequentially with polar and nonpolar solvents, concentrated, and directly analyzed by high resolution gas chromatography coupled to a mass spectrometer operating in the selected ion monitoring mode. In this paper, we analyzed two homogenized samples of whole fish tissues with spiked synthetic musk compounds using closed-loop stripping analysis (CLSA) and pressurized liquid extraction (PLE). The analytes were not recovered quantitatively but the extraction yield was sufficiently reproducible for at least semi-quantitative purposes (screening). The method was less expensive to implement and required significantly less sample preparation than the PLE technique. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water,

  7. Catalytic glycerol steam reforming for hydrogen production

    International Nuclear Information System (INIS)

    Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

    2015-01-01

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H 2 . In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al 2 O 3 . The catalyst was prepared by wet impregnation method and characterized through different methods: N 2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H 2 , CH 4 , CO, CO 2 . The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H 2 O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%

  8. Catalytic glycerol steam reforming for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Monica, E-mail: monica.dan@itim-cj.ro; Mihet, Maria, E-mail: maria.mihet@itim-cj.ro; Lazar, Mihaela D., E-mail: diana.lazar@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj Napoca (Romania)

    2015-12-23

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterized through different methods: N{sub 2} adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 2}O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  9. First-principles study of H, O, and N adsorption on metal embedded carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Detian [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Luo, Haijun, E-mail: luohaijun@wzu.edu.cn [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Cai, Jianqiu [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Cheng, Yongjun [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Shao, Xiji [Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China); Dong, Changkun, E-mail: dck@wzu.edu.cn [Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou, Gansu 730000 (China); Institute of Micro-nano Structures & Optoelectronics, Wenzhou University, Wenzhou, Zhejiang 325035 (China)

    2017-05-01

    Highlights: • Ni or Fe embedment and high atomic adsorption coverage benefit applications like hydrogen storage and field emission. • Ni or Fe embedment could help tune the catalytic properties. • Ni or Fe embedment enhances the adatom-SWNT interaction significantly. - Abstract: The density functional theory calculation has been conducted to investigate the structural and electronic properties, including the adsorption energies, bond structures, work functions, charge transfer behaviors, and density of states for pristine, Ni-, and Fe-embedded capped (5, 5) single-walled carbon nanotubes (SWNTs) with different coverage of atomic hydrogen, oxygen, and nitrogen adsorptions. Ni or Fe embedment enhances the adatom-SWNT interactions significantly for three kinds of gas atoms with the increases of the adsorption energies. The SWNT work function drops with H adsorption, while Ni or Fe embedment assists further the reduction. When increasing the coverage, the adsorption energy decreases and the work function climbs for O adsorption, but the nitrogen adsorption energy increases. The Bader charge transfer analysis implies that the cap possesses higher oxygen reduction activities than the tube, and the density of states analysis shows that Ni or Fe embedment deepens the C-adatom hybridizations.

  10. Fundamentals of high pressure adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.P.; Zhou, L. [Tianjin University, Tianjin (China). High Pressure Adsorption Laboratory

    2009-12-15

    High-pressure adsorption attracts research interests following the world's attention to alternative fuels, and it exerts essential effect on the study of hydrogen/methane storage and the development of novel materials addressing to the storage. However, theoretical puzzles in high-pressure adsorption hindered the progress of application studies. Therefore, the present paper addresses the major theoretical problems that challenged researchers: i.e., how to model the isotherms with maximum observed in high-pressure adsorption; what is the adsorption mechanism at high pressures; how do we determine the quantity of absolute adsorption based on experimental data. Ideology and methods to tackle these problems are elucidated, which lead to new insights into the nature of high-pressure adsorption and progress in application studies, for example, in modeling multicomponent adsorption, hydrogen storage, natural gas storage, and coalbed methane enrichment, was achieved.

  11. Noise analysis due to strip resistance in the ATLAS SCT silicon strip module

    International Nuclear Information System (INIS)

    Kipnis, I.

    1996-08-01

    The module is made out of four 6 cm x 6 cm single sided Si microstrip detectors. Two detectors are butt glued to form a 12 cm long mechanical unit and strips of the two detectors are electrically connected to form 12 cm long strips. The butt gluing is followed by a back to back attachment. The module in this note is the Rφ module where the electronics is oriented parallel to the strip direction and bonded directly to the strips. This module concept provides the maximum signal-to-noise ratio, particularly when the front-end electronics is placed near the middle rather than at the end. From the noise analysis, it is concluded that the worst-case ΔENC (far-end injection) between end- and center-tapped modules will be 120 to 210 el. rms (9 to 15%) for a non-irradiated detector and 75 to 130 el. rms (5 to 9%) for an irradiated detector, for a metal strip resistance of 10 to 20 Ω/cm

  12. Catalytic removal of sulfur dioxide from dibenzothiophene sulfone over Mg-Al mixed oxides supported on mesoporous silica.

    Science.gov (United States)

    You, Nansuk; Kim, Min Ji; Jeong, Kwang-Eun; Jeong, Soon-Yong; Park, Young-Kwon; Jeon, Jong-Ki

    2010-05-01

    Dibenzothiophene sulfone (DBTS), one of the products of the oxidative desulfurization of heavy oil, can be removed through extraction as well as by an adsorption process. It is necessary to utilize DBTS in conjunction with catalytic cracking. An object of the present study is to provide an Mg-Al-mesoporous silica catalyst for the removal of sulfur dioxide from DBTS. The characteristics of the Mg-Al-mesoporous silica catalyst were investigated through N2 adsorption, XRD, ICP, and XRF. An Mg-Al-mesoporous silica catalyst formulated in a direct incorporation method showed higher catalytic performance compared to pure MgO during the catalytic removal of sulfur dioxide from DBTS. The higher dispersion of Mg as well as the large surface area of the Mg-Al-mesoporous silica catalyst strongly influenced the catalyst basicity in DBTS cracking.

  13. Traps for phosphorus adsorption

    International Nuclear Information System (INIS)

    Montoya, Nawer D; Villegas, Wilson E; Rodriguez, Lino M; Taborda, Nelson; Montes de C, Consuelo

    2001-01-01

    Several AL 2 O 3 supported oxides such as: NiO, CuO, Co 2 O 3 BaO, CeO 2 and ZnO were investigated for phosphorus adsorption. Zno/y-Al 2 O 3 exhibited the highest phosphorus adsorption capacity. However, since it diminishes the activity of to the reaction mixture it should be located upstream of the NoX catalyst, i.e. 0,3% Pd-H-MOR, in order to protect it against p poisoning. The treatment procedure with citric acid was effective for the removal of more than 70% phosphorus from the adsorbent, ZnO/y-Al 2 O 3

  14. Experimental study on removals of SO2 and NO(x) using adsorption of activated carbon/microwave desorption.

    Science.gov (United States)

    Ma, Shuang-Chen; Yao, Juan-Juan; Gao, Li; Ma, Xiao-Ying; Zhao, Yi

    2012-09-01

    Experimental studies on desulfurization and denitrification were carried out using activated carbon irradiated by microwave. The influences of the concentrations of nitric oxide (NO) and sulfur dioxide (SO2), the flue gas coexisting compositions, on adsorption properties of activated carbon and efficiencies of desulfurization and denitrification were investigated. The results show that adsorption capacity and removal efficiency of NO decrease with the increasing of SO2 concentrations in flue gas; adsorption capacity of NO increases slightly first and drops to 12.79 mg/g, and desulfurization efficiency descends with the increasing SO2 concentrations. Adsorption capacity of SO2 declines with the increasing of O2 content in flue gas, but adsorption capacity of NO increases, and removal efficiencies of NO and SO2 could be larger than 99%. Adsorption capacity of NO declines with the increase of moisture in the flue gas, but adsorption capacity of SO2 increases and removal efficiencies of NO and SO2 would be relatively stable. Adsorption capacities of both NO and SO2 decrease with the increasing of CO2 content; efficiencies of desulfurization and denitrification augment at the beginning stage, then start to fall when CO2 content exceeds 12.4%. The mechanisms of this process are also discussed. The prominent SO2 and NOx treatment techniques in power plants are wet flue gas desulfurization (FGD) and the catalytic decomposition method like selective catalytic reduction (SCR) or nonselective catalytic reduction (NSCR). However, these processes would have some difficulties in commercial application due to their high investment, requirement of expensive catalysts and large-scale equipment, and so on. A simple SO2 and NOx reduction utilizing decomposition by microwave energy method can be used. The pollutants control of flue gas in the power plants by the method of microwave-induced decomposition using adsorption of activated carbon/microwave desorption can meet the

  15. AIR STRIPPING AND OFF-GAS ADSORPTION FOR THE REMOVAL OF MTBE FROM DRINKING WATER

    Science.gov (United States)

    Methyl-tertiary butyl ether (MTBE) is a synthetic organic chemical, primarily used for oxgenating fuel. The 1990 Federal Clean Air Act Amendments mandated the use of fuel oxgenates in areas where air quality did not meet national standards, which led to widespread use of MTBE in...

  16. Determination of triazines in hemodialysis saline solutions by adsorptive stripping voltammetry after extraction in acetonitrile

    Directory of Open Access Journals (Sweden)

    Nascimento Paulo Cícero do

    2003-01-01

    Full Text Available A method for the voltammetric determination of 2-methylthio-4,6-dialkylamino-1,3,5-triazine (triazines herbicides in hemodialysis (HD saline solutions was developed. The herbicides were detected in the saline solutions at the hanging mercury drop electrode (HMDE with high sensitivities only after extraction of the analytes in acetonitrile (ACN. The salting out effect originated by the saline environment existing in the solutions enabled the extractions. The volume ratio between the saline and ACN phases was investigated in order to find the best sensitivity to detect the triazines. The speciation amongst them (ametryn, desmetryn, prometryn and terbutryn was not possible. Recoveries between 88 and 107% were calculated in spiked samples, and detection limits of 0.03 mumol L-1 were calculated for the triazines in the saline samples using this methodology.

  17. Adsorptive stripping voltammetric study of vitamin B1 at multi-walled carbon nanotube paste electrode

    Directory of Open Access Journals (Sweden)

    Pradeep Kumar Brahman

    2016-11-01

    The reduction peak current varies linearly with the concentration of vitamin B1 over the range of 1.0 × 10−7–1.0 × 10−6 M. The limits of detection and quantification of the pure drug are 1.1 × 10−10 M and 2.0 × 10−9 M, with the correlation coefficient, r = 0.997 and the relative standard deviation, RSD = 1.2% (n = 5. Experimental results reveal that the MWCNTPE has advantages of small background current, high signal to background current ratio and good reproducibility.

  18. Diffusion Influenced Adsorption Kinetics.

    Science.gov (United States)

    Miura, Toshiaki; Seki, Kazuhiko

    2015-08-27

    When the kinetics of adsorption is influenced by the diffusive flow of solutes, the solute concentration at the surface is influenced by the surface coverage of solutes, which is given by the Langmuir-Hinshelwood adsorption equation. The diffusion equation with the boundary condition given by the Langmuir-Hinshelwood adsorption equation leads to the nonlinear integro-differential equation for the surface coverage. In this paper, we solved the nonlinear integro-differential equation using the Grünwald-Letnikov formula developed to solve fractional kinetics. Guided by the numerical results, analytical expressions for the upper and lower bounds of the exact numerical results were obtained. The upper and lower bounds were close to the exact numerical results in the diffusion- and reaction-controlled limits, respectively. We examined the validity of the two simple analytical expressions obtained in the diffusion-controlled limit. The results were generalized to include the effect of dispersive diffusion. We also investigated the effect of molecular rearrangement of anisotropic molecules on surface coverage.

  19. Adsorption of cadmium ions on nickel surface skeleton catalysts and its effect on reaction of cathodic hydrogen evolution

    International Nuclear Information System (INIS)

    Korovin, N.V.; Udris, E.Ya.; Savel'eva, O.N.

    1986-01-01

    Cadmium adsorption from different concentration CdSO 4 solutions on nickel surface skeleton catalysts (Ni ssc ) is studied by recording of polarization and potentiodynamic curves using electron microscopy and X-ray spectrometry. Main regularities of cadmium adsorption on Ni ssc are shown to be similar to those on smooth and skeleton nickel. A conclusion is drawn that increase of catalytic activity in reaction of cathodic hydrogen evolution from alkali solutions of Ni ssc base electrodes after their treatment in solutions containing Cd 2+ ions is due to irreversible desorption of strongly and averagely bound hydrogen from electrode surface at cadmium adsorption on them

  20. Low concentration volatile organic pollutants removal in combined adsorber-desorber-catalytic reactor system

    Directory of Open Access Journals (Sweden)

    Arsenijević Zorana

    2008-01-01

    Full Text Available The removal of volatile organic compounds (VOCs from numerous emission sources is of crucial importance due to more rigorous demands on air quality. Different technologies can be used to treat the VOCs from effluent gases: absorption, physical adsorption, open flame combustion, thermal and catalytic incineration. Their appropriateness for the specific process depends on several factors such as efficiency, energy consumption, secondary pollution, capital investments etc. The distinctive features of the catalytic combustion are high efficiency and selectivity toward be­nign products, low energy consumption and absence of secondary polluti­on. The supported noble catalysts are widely used for catalytic incineration due to their low ignition temperatures and high thermal and chemical stability. In our combined system adsorption and desorption are applied in the spouted bed with draft tube (SBDT unit. The annular zone, loaded with sorbent, was divided in adsorption and desorption section. Draft tube enabled sorbent recirculation between sections. Combustion of desorbed gases to CO2 and water vapor are realized in additive catalytic reactor. This integrated device provided low concentrations VOCs removal with reduced energy consumption. Experiments were conducted on a pilot unit of 220 m3/h nominal capacity. The sorbent was activated carbon, type K81/B - Trayal Corporation, Krusevac. A sphere shaped commercial Pt/Al2O3 catalyst with "egg-shell" macro-distribution was used for the investigation of xylene deep oxidation. Within this paper the investigations of removal of xylene vapors, a typical pollutant in production of liquid pesticides, in combined adsorber/desorber/catalytic reactor system is presented.

  1. Protein adsorption onto nanozeolite: effect of micropore openings.

    Science.gov (United States)

    Wu, Jiamin; Li, Xiang; Yan, Yueer; Hu, Yuanyuan; Zhang, Yahong; Tang, Yi

    2013-09-15

    A clear and deep understanding of protein adsorption on porous surfaces is desirable for the reasonable design and applications of porous materials. In this study, the effect of surface micropores on protein adsorption was systematically investigated by comparing adsorption behavior of cytochrome c (Cyto-c) and Candida antarctica Lipase B (CALB) on porous and non-porous nanozeolites silicalite-1 and Beta. It was found that micropore openings on the surface of nanozeolites played a key role in determining adsorption affinity, conformations, and activities of proteins. Both Cyto-c and CALB showed higher affinity to porous nanozeolites than to non-porous ones, resulting in greater conformational change of proteins on porous surfaces which in turn affected their bio-catalytic performance. The activity of Cyto-c improved while that of CALB decreased on porous nanozeolites. Recognition of certain amino acid residues or size-matching secondary structures by micropore openings on the surface of nanozeolites was proposed to be the reason. Moreover, the pore opening effect of porous nanozeolites on protein behavior could be altered by changing protein coverage on them. This study gives a novel insight into the interaction between proteins and microporous materials, which will help to guide the rational fabrication and bio-applications of porous materials in the future. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Catalytic bioreactors and methods of using same

    Science.gov (United States)

    Worden, Robert Mark; Liu, Yangmu Chloe

    2017-07-25

    Various embodiments provide a bioreactor for producing a bioproduct comprising one or more catalytically active zones located in a housing and adapted to keep two incompatible gaseous reactants separated when in a gas phase, wherein each of the one or more catalytically active zones may comprise a catalytic component retainer and a catalytic component retained within and/or thereon. Each of the catalytically active zones may additionally or alternatively comprise a liquid medium located on either side of the catalytic component retainer. Catalytic component may include a microbial cell culture located within and/or on the catalytic component retainer, a suspended catalytic component suspended in the liquid medium, or a combination thereof. Methods of using various embodiments of the bioreactor to produce a bioproduct, such as isobutanol, are also provided.

  3. Catalytic activity of Au nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Janssens, Ton V.W.; Clausen, Bjerne

    2007-01-01

    Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with par......Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change...... with particle size. We find that the fraction of low-coordinated Au atoms scales approximately with the catalytic activity, suggesting that atoms on the corners and edges of Au nanoparticles are the active sites. This effect is explained using density functional calculations....

  4. Copper adsorption in tropical oxisols

    Directory of Open Access Journals (Sweden)

    Silveira Maria Lucia Azevedo

    2003-01-01

    Full Text Available Cu adsorption, at concentrations between 0 to 800 mg L-1, was evaluated in surface and subsurface samples of three Brazilian soils: a heavy clayey-textured Rhodic Hapludalf (RH, a heavy clayey-textured Anionic ''Rhodic'' Acrudox (RA and a medium-textured Anionic ''Xanthic'' Acrudox (XA. After adsorption, two consecutive extractions were performed to the samples which received 100 mg L-1 copper. Surface samples adsorbed higher amounts of Cu than the subsurface, and exhibited lower Cu removed after the extractions, reinforcing the influence of the organic matter in the reactions. Cu adsorption was significant in the subsurface horizons of the Oxisols, despite the positive balance of charge, demonstrating the existence of mechanisms for specific adsorption, mainly related to the predominance of iron and aluminum oxides in the mineral fractions. In these samples, Cu was easily removed from the adsorption sites. RH demonstrated a higher capacity for the Cu adsorption in both horizons.

  5. [Effect of SO2 volume fraction in flue gas on the adsorption behaviors adsorbed by ZL50 activated carbon and kinetic analysis].

    Science.gov (United States)

    Gao, Ji-xian; Wang, Tie-feng; Wang, Jin-fu

    2010-05-01

    The influence of SO2 dynamic adsorption behaviors using ZL50 activated carbon for flue gas desulphurization and denitrification under different SO2 volume fraction was investigated experimentally, and the kinetic analysis was conducted by kinetic models. With the increase of SO2 volume fraction in flue gas, the SO2 removal ratio and the activity ratio of ZL50 activated carbon decreased, respectively, and SO2 adsorption rate and capacity increased correspondingly. The calculated results indicate that Bangham model has the best prediction effect, the chemisorption processes of SO2 was significantly affected by catalytic oxidative reaction. The adsorption rate constant of Lagergren's pseudo first order model increased with the increase of inlet SO, volume fraction, which indicated that catalytic oxidative reaction of SO2 adsorbed by ZL50 activated carbon may be the rate controlling step in earlier adsorption stage. The Lagergren's and Bangham's initial adsorption rate were deduced and defined, respectively. The Ho's and Elovich's initial adsorption rate were also deduced in this paper. The Bangham's initial adsorption rate values were defined in good agreement with those of experiments. The defined Bangham's adsorptive reaction kinetic model can describe the SO2 dynamic adsorption rate well. The studied results indicated that the SO2 partial order of initial reaction rate was one or adjacent to one, while the O2 and water vapor partial order of initial reaction rate were constants ranging from 0.15-0.20 and 0.45-0.50, respectively.

  6. Real life experimental determination of platinum group metals content in automotive catalytic converters

    Science.gov (United States)

    Yakoumis, I.; Moschovi, A. M.; Giannopoulou, I.; Panias, D.

    2018-03-01

    The real life experimental protocol for the preparation of spent automobile catalyst samples for elemental analysis is thoroughly described in the following study. Collection, sorting and dismantling, homogenization and sample preparation for X-Ray fluorescence spectroscopy and Atomic Adsorption Spectroscopy combined with Inductive coupled plasma mass spectrometry are discussed in detail for both ceramic and metallic spent catalysts. The concentrations of Platinum Group Metals (PGMs) in spent catalytic converters are presented based on typical consignments of recycled converters (more than 45,000 pieces) from the Greek Market. The conclusions clearly denoted commercial metallic catalytic foil contains higher PGMs loading than ceramic honeycombs. On the other hand, the total PGMs loading in spent ceramic catalytic converters has been found higher than the corresponding value for the metallic ones.

  7. Synthesis, Characterization, and Catalytic Activity of Pd(II Salen-Functionalized Mesoporous Silica

    Directory of Open Access Journals (Sweden)

    Rotcharin Sawisai

    2017-01-01

    Full Text Available Salen ligand synthesized from 2-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde was used as a palladium chelating ligand for the immobilization of the catalytic site. Mesoporous silica supported palladium catalysts were prepared by immobilizing Pd(OAc2 onto a mesoporous silica gel through the coordination of the imine-functionalized mesoporous silica gel. The prepared catalysts were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray (EDX, inductivity couple plasma (ICP, nitrogen adsorption-desorption, and Fourier transform infrared (FT-IR spectroscopy. The solid catalysts showed higher activity for the hydroamination of C-(tetra-O-acetyl-β-D-galactopyranosylallene with aromatic amines compared with the corresponding homogenous catalyst. The heterogeneous catalytic system can be easily recovered by simple filtration and reused for up to five cycles with no significant loss of catalytic activity.

  8. Electronic states of carbon alloy catalysts and nitrogen substituent effects on catalytic activity

    Science.gov (United States)

    Hata, Tomoyuki; Ushiyama, Hiroshi; Yamashita, Koichi

    2013-03-01

    In recent years, Carbon Alloy Catalysts (CACs) are attracting attention as a candidate for non-platinum-based cathode catalysts in fuel cells. Oxygen reduction reactions at the cathode are divided into two elementary processes, electron transfer and oxygen adsorption. The electron transfer reaction is the rate-determining, and by comparison of energy levels, catalytic activity can be evaluated quantitatively. On the other hand, to begin with, adsorption mechanism is obscure. The purpose of this study is to understand the effect of nitrogen substitution and oxygen adsorption mechanism, by first-principle electronic structure calculations for nitrogen substituted models. To reproduce the elementary processes of oxygen adsorption, we assumed that the initial structures are formed based on the Pauling model, a CACs model and nitrogen substituted CACs models in which various points are replaced with nitrogen. When we try to focus only on the DOS peaks of oxygen, in some substituted model that has high adsorption activity, a characteristic partial occupancy state was found. We conclude that this state will affect the adsorption activity, and discuss on why partially occupied states appear with simplification by using an orbital correlation diagram.

  9. High pressure water jet cutting and stripping

    Science.gov (United States)

    Hoppe, David T.; Babai, Majid K.

    1991-01-01

    High pressure water cutting techniques have a wide range of applications to the American space effort. Hydroblasting techniques are commonly used during the refurbishment of the reusable solid rocket motors. The process can be controlled to strip a thermal protective ablator without incurring any damage to the painted surface underneath by using a variation of possible parameters. Hydroblasting is a technique which is easily automated. Automation removes personnel from the hostile environment of the high pressure water. Computer controlled robots can perform the same task in a fraction of the time that would be required by manual operation.

  10. Nonlinear optical model for strip plasmonic waveguides

    DEFF Research Database (Denmark)

    Lysenko, Oleg; Bache, Morten; Lavrinenko, Andrei

    2016-01-01

    This paper presents a theoretical model of nonlinear optical properties for strip plasmonic waveguides. The particular waveguides geometry that we investigate contains a gold core, adhesion layers, and silicon dioxide cladding. It is shown that the third-order susceptibility of the gold core...... significantly depends on the layer thickness and has the dominant contribution to the effective third-order susceptibility of the long-range plasmon polariton mode. This results in two nonlinear optical effects in plasmonic waveguides, which we experimentally observed and reported in [Opt. Lett. 41, 317 (2016...... approaches. (C) 2016 Optical Society of America...

  11. Energy Fuels Nuclear, Inc. Arizona Strip Operations

    International Nuclear Information System (INIS)

    Pool, T.C.

    1993-01-01

    Founded in 1975 by uranium pioneer, Robert W. Adams, Energy Fuels Nuclear, Inc. (EFNI) emerged as the largest US uranium mining company by the mid-1980s. Confronting the challenges of declining uranium market prices and the development of high-grade ore bodies in Australia and Canada, EFNI aggressively pursued exploration and development of breccia-pipe ore bodies in Northwestern Arizona. As a result, EFNI's production for the Arizona Strip of 18.9 million pounds U 3 O 8 over the period 1980 through 1991, maintained the company's status as a leading US uranium producer

  12. Reaction Current Phenomenon in Bifunctional Catalytic Metal-Semiconductor Nanostructures

    Science.gov (United States)

    Hashemian, Mohammad Amin

    Energy transfer processes accompany every elementary step of catalytic chemical processes on material surface including molecular adsorption and dissociation on atoms, interactions between intermediates, and desorption of reaction products from the catalyst surface. Therefore, detailed understanding of these processes on the molecular level is of great fundamental and practical interest in energy-related applications of nanomaterials. Two main mechanisms of energy transfer from adsorbed particles to a surface are known: (i) adiabatic via excitation of quantized lattice vibrations (phonons) and (ii) non-adiabatic via electronic excitations (electron/hole pairs). Electronic excitations play a key role in nanocatalysis, and it was recently shown that they can be efficiently detected and studied using Schottky-type catalytic nanostructures in the form of measureable electrical currents (chemicurrents) in an external electrical circuit. These nanostructures typically contain an electrically continuous nanocathode layers made of a catalytic metal deposited on a semiconductor substrate. The goal of this research is to study the direct observations of hot electron currents (chemicurrents) in catalytic Schottky structures, using a continuous mesh-like Pt nanofilm grown onto a mesoporous TiO2 substrate. Such devices showed qualitatively different and more diverse signal properties, compared to the earlier devices using smooth substrates, which could only be explained on the basis of bifunctionality. In particular, it was necessary to suggest that different stages of the reaction are occurring on both phases of the catalytic structure. Analysis of the signal behavior also led to discovery of a formerly unknown (very slow) mode of the oxyhydrogen reaction on the Pt/TiO2(por) system occurring at room temperature. This slow mode was producing surprisingly large stationary chemicurrents in the range 10--50 microA/cm2. Results of the chemicurrent measurements for the bifunctional

  13. Insights into the effect of coverage on CO adsorption and dissociation over Rh(1 0 0) surface: A theoretical study

    International Nuclear Information System (INIS)

    Zhao, Xiaojun; Zhang, Riguang; Ling, Lixia; Wang, Baojun

    2014-01-01

    Graphical abstract: - Highlights: • The adsorption energies gradually decrease with the increasing of CO coverage on Rh(1 0 0). • CO reaches the saturated adsorption with the coverage of 12/12 ML on Rh(1 0 0). • Both CO desorption and dissociation co-exist at the coverage less than or equal to 2/12 ML. • Only molecule CO adsorption is favored at the coverage greater than or equal to 3/12 ML. • Only molecule CO adsorption form exists in syngas conversion on Rh catalyst. - Abstract: The adsorption, dissociation and desorption of CO at different coverage over Rh(1 0 0) surface have been systematically investigated using density functional theory method together with the periodic slab model. Our results show that at the coverage less than or equal to 4/12 ML, CO favored the most stable bridge site adsorption, and the adsorption energies of CO have little difference; while at the coverage greater than or equal to 5/12 ML, the lateral repulsive interaction begins to affect the adsorption structures and the corresponding adsorption energies of adsorbed CO molecules, and the interaction will be stronger with the increasing of CO coverage, which leads to CO migration over Rh(1 0 0) surface when CO coverage is greater than or equal to 10/12 ML. The adsorption energies of these CO molecules will decrease successively until the saturated adsorption with the CO coverage of 12/12 ML. Further calculations on CO dissociation indicate that when CO coverage is greater than or equal to 3/12 ML, the dissociation of adsorbed CO molecules will be unfavorable both kinetically and thermodynamically, suggesting that only molecule CO adsorption are favored. Considering the catalytic activity of Rh(1 0 0) surface toward CO dissociation and the higher CO coverage under the continuous supply of CO in syngas conversion, it is to be expected that only molecule CO adsorption exist on Rh catalyst

  14. Adsorption and collective paramagnetism

    CERN Document Server

    Selwood, Pierce W

    1962-01-01

    Adsorption and Collective Paramagnetism describes a novel method for studying chemisorption. The method is based on the change in the number of unpaired electrons in the adsorbent as chemisorption occurs. The method is applicable to almost all adsorbates, but it is restricted to ferromagnetic adsorbents such as nickel, which may be obtained in the form of very small particles, that is to say, to ferromagnetic adsorbents with a high specific surface. While almost all the data used illustratively have been published elsewhere this is the first complete review of the subject. The book is addresse

  15. Apparatus for measuring profile thickness of strip material

    International Nuclear Information System (INIS)

    Hold, A.C.

    1982-01-01

    Apparatus for measuring the thickness profile of steel strip comprises a radiation source reciprocally movable in a stepwise fashion (by a belt) across the strip width on one side thereof and a single elongated detector on the other side of the strip aligned with the scanning source. This detector may be a fluorescent scintillator detector or an ionisation chamber. Means are provided for sensing the degree of excitation in the detector in synchronism with the scanning source whereby to provide an output representative of the thickness profile of the strip. (author)

  16. Stability of barotropic vortex strip on a rotating sphere

    Science.gov (United States)

    Sohn, Sung-Ik; Sakajo, Takashi; Kim, Sun-Chul

    2018-02-01

    We study the stability of a barotropic vortex strip on a rotating sphere, as a simple model of jet streams. The flow is approximated by a piecewise-continuous vorticity distribution by zonal bands of uniform vorticity. The linear stability analysis shows that the vortex strip becomes stable as the strip widens or the rotation speed increases. When the vorticity constants in the upper and the lower regions of the vortex strip have the same positive value, the inner flow region of the vortex strip becomes the most unstable. However, when the upper and the lower vorticity constants in the polar regions have different signs, a complex pattern of instability is found, depending on the wavenumber of perturbations, and interestingly, a boundary far away from the vortex strip can be unstable. We also compute the nonlinear evolution of the vortex strip on the rotating sphere and compare with the linear stability analysis. When the width of the vortex strip is small, we observe a good agreement in the growth rate of perturbation at an early time, and the eigenvector corresponding to the unstable eigenvalue coincides with the most unstable part of the flow. We demonstrate that a large structure of rolling-up vortex cores appears in the vortex strip after a long-time evolution. Furthermore, the geophysical relevance of the model to jet streams of Jupiter, Saturn and Earth is examined.

  17. Strip type radiation detector and method of making same

    International Nuclear Information System (INIS)

    Jantsch, O.; Feigt, I.; Willig, W.R.

    1976-01-01

    An improved strip detector and a method for making such a detector in which a high resistivity N conduction semiconductor body has electrode strips formed thereon by diffusion is described. The strips are formed so as to be covered by an oxide layer at the surface point of the PN junction and in which the opposite side of the semiconductor body then has a substantial amount of material etched away to form a thin semiconductor upon which strip electrodes which are perpendicular to the electrodes on the first side are then placed

  18. Stability of barotropic vortex strip on a rotating sphere.

    Science.gov (United States)

    Sohn, Sung-Ik; Sakajo, Takashi; Kim, Sun-Chul

    2018-02-01

    We study the stability of a barotropic vortex strip on a rotating sphere, as a simple model of jet streams. The flow is approximated by a piecewise-continuous vorticity distribution by zonal bands of uniform vorticity. The linear stability analysis shows that the vortex strip becomes stable as the strip widens or the rotation speed increases. When the vorticity constants in the upper and the lower regions of the vortex strip have the same positive value, the inner flow region of the vortex strip becomes the most unstable. However, when the upper and the lower vorticity constants in the polar regions have different signs, a complex pattern of instability is found, depending on the wavenumber of perturbations, and interestingly, a boundary far away from the vortex strip can be unstable. We also compute the nonlinear evolution of the vortex strip on the rotating sphere and compare with the linear stability analysis. When the width of the vortex strip is small, we observe a good agreement in the growth rate of perturbation at an early time, and the eigenvector corresponding to the unstable eigenvalue coincides with the most unstable part of the flow. We demonstrate that a large structure of rolling-up vortex cores appears in the vortex strip after a long-time evolution. Furthermore, the geophysical relevance of the model to jet streams of Jupiter, Saturn and Earth is examined.

  19. Strip defect recognition in electrical tests of silicon microstrip sensors

    Energy Technology Data Exchange (ETDEWEB)

    Valentan, Manfred, E-mail: valentan@mpp.mpg.de

    2017-02-11

    This contribution describes the measurement procedure and data analysis of AC-coupled double-sided silicon microstrip sensors with polysilicon resistor biasing. The most thorough test of a strip sensor is an electrical measurement of all strips of the sensor; the measured observables include e.g. the strip's current and the coupling capacitance. These measurements are performed to find defective strips, e.g. broken capacitors (pinholes) or implant shorts between two adjacent strips. When a strip has a defect, its observables will show a deviation from the “typical value”. To recognize and quantify certain defects, it is necessary to determine these typical values, i.e. the values the observables would have without the defect. As a novel approach, local least-median-of-squares linear fits are applied to determine these “would-be” values of the observables. A least-median-of-squares fit is robust against outliers, i.e. it ignores the observable values of defective strips. Knowing the typical values allows to recognize, distinguish and quantify a whole range of strip defects. This contribution explains how the various defects appear in the data and in which order the defects can be recognized. The method has been used to find strip defects on 30 double-sided trapezoidal microstrip sensors for the Belle II Silicon Vertex Detector, which have been measured at the Institute of High Energy Physics, Vienna (Austria).

  20. Pavement Stripping in Saudi Arabia: Prediction and Prevention

    Directory of Open Access Journals (Sweden)

    H.I. Al-Abdul Wahhab

    2004-12-01

    Full Text Available Pavement weathering or stripping is a major distress in highway networks in arid regions. Using the Saudi Arabian road network as a case study area, seventeen road test sections were selected, out of which eight were stripped and nine were non-stripped. Aggregates from quarries used to build these sections were also collected and subjected to detailed physical and chemical tests to evaluate the ability of these tests to distinguish between stripped and non-stripped sections. The modified Lottman test was used to distinguish between compacted mixes. In addition, the Swedish Rolling Bottle test, was also found to be effective in being able to distinguish between different asphalt-aggregates for stripping potential. Eleven anti-stripping liquid additives, lime and cement, in addition to two polymers, were evaluated for their ability to reduce/eliminate stripping potential of stripping-prone aggregates. It was found that EE-2 Polymer, Portland cement, and their combination were effective with all aggregate sources.

  1. Competitive Adsorption between Nanoparticles and Surface Active Ions for the Oil-Water Interface.

    Science.gov (United States)

    Hua, Xiaoqing; Bevan, Michael A; Frechette, Joelle

    2018-04-24

    Nanoparticles (NPs) can add functionality (e.g., catalytic, optical, rheological) to an oil-water interface. Adsorption of ∼10 nm NPs can be reversible; however, the mechanisms for adsorption and its effects on surface pressure remain poorly understood. Here we demonstrate how the competitive reversible adsorption of NPs and surfactants at fluid interfaces can lead to independent control of both the adsorbed amount and surface pressure. In contrast to prior work, both species investigated (NPs and surfactants) interact reversibly with the interface and without the surface active species binding to NPs. Independent measurements of the adsorption and surface pressure isotherms allow determination of the equation of state (EOS) of the interface under conditions where the NPs and surfactants are both in dynamic equilibrium with the bulk phase. The adsorption and surface pressure measurements are performed with gold NPs of two different sizes (5 and 10 nm), at two pH values, and across a wide concentration range of surfactant (tetrapentylammonium, TPeA + ) and NPs. We show that free surface active ions compete with NPs for the interface and give rise to larger surface pressures upon the adsorption of NPs. Through a competitive adsorption model, we decouple the contributions of NPs wetting at the interface and their surface activity on the measured surface pressure. We also demonstrate reversible control of adsorbed amount via changes in the surfactant concentration or the aqueous phase pH.

  2. Extraction or adsorption? Voltammetric assessment of protamine transfer at ionophore-based polymeric membranes.

    Science.gov (United States)

    Garada, Mohammed B; Kabagambe, Benjamin; Amemiya, Shigeru

    2015-01-01

    Cation-exchange extraction of polypeptide protamine from water into an ionophore-based polymeric membrane has been hypothesized as the origin of a potentiometric sensor response to this important heparin antidote. Here, we apply ion-transfer voltammetry not only to confirm protamine extraction into ionophore-doped polymeric membranes but also to reveal protamine adsorption at the membrane/water interface. Protamine adsorption is thermodynamically more favorable than protamine extraction as shown by cyclic voltammetry at plasticized poly(vinyl chloride) membranes containing dinonylnaphthalenesulfonate as a protamine-selective ionophore. Reversible adsorption of protamine at low concentrations down to 0.038 μg/mL is demonstrated by stripping voltammetry. Adsorptive preconcentration of protamine at the membrane/water interface is quantitatively modeled by using the Frumkin adsorption isotherm. We apply this model to ensure that stripping voltammograms are based on desorption of all protamine molecules that are transferred across the interface during a preconcentration step. In comparison to adsorption, voltammetric extraction of protamine requires ∼0.2 V more negative potentials, where a potentiometric super-Nernstian response to protamine is also observed. This agreement confirms that the potentiometric protamine response is based on protamine extraction. The voltammetrically reversible protamine extraction results in an apparently irreversible potentiometric response to protamine because back-extraction of protamine from the membrane extremely slows down at the mixed potential based on cation-exchange extraction of protamine. Significantly, this study demonstrates the advantages of ion-transfer voltammetry over potentiometry to quantitatively and mechanistically assess protamine transfer at ionophore-based polymeric membranes as foundation for reversible, selective, and sensitive detection of protamine.

  3. Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

    OpenAIRE

    Chen, Qing; Tian, Yuanyuan; Li, Peng; Yan, Changhui; Pang, Yu; Zheng, Li; Deng, Hucheng; Zhou, Wen; Meng, Xianghao

    2017-01-01

    Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indi...

  4. Monitoring the CMS strip tracker readout system

    International Nuclear Information System (INIS)

    Mersi, S; Bainbridge, R; Cripps, N; Fulcher, J; Wingham, M; Baulieu, G; Bel, S; Delaere, C; Drouhin, F; Mirabito, L; Cole, J; Giassi, A; Gross, L; Hahn, K; Nikolic, M; Tkaczyk, S

    2008-01-01

    The CMS Silicon Strip Tracker at the LHC comprises a sensitive area of approximately 200 m 2 and 10 million readout channels. Its data acquisition system is based around a custom analogue front-end chip. Both the control and the readout of the front-end electronics are performed by off-detector VME boards in the counting room, which digitise the raw event data and perform zero-suppression and formatting. The data acquisition system uses the CMS online software framework to configure, control and monitor the hardware components and steer the data acquisition. The first data analysis is performed online within the official CMS reconstruction framework, which provides many services, such as distributed analysis, access to geometry and conditions data, and a Data Quality Monitoring tool based on the online physics reconstruction. The data acquisition monitoring of the Strip Tracker uses both the data acquisition and the reconstruction software frameworks in order to provide real-time feedback to shifters on the operational state of the detector, archiving for later analysis and possibly trigger automatic recovery actions in case of errors. Here we review the proposed architecture of the monitoring system and we describe its software components, which are already in place, the various monitoring streams available, and our experiences of operating and monitoring a large-scale system

  5. Microwave assisted synthesis of hydroxyapatite nano strips

    Energy Technology Data Exchange (ETDEWEB)

    Ruban Kumar, A.; Kalainathan, S.; Saral, A.M. [School of Advanced Sciences, VIT University, Vellore 632014, Tamil Nadu (India)

    2010-07-15

    Synthesis of hydroxyapatite (HAP) nano strips was carried out by chemical precipitation method followed by microwave irradiation. The microwave assisted reactions proceed at fast rates. It is found that the presence of the complex reagent EDTA plays an important role in the morphological changes of nanostructure hydroxyapatite. EDTA acts as a hexadentate unit by wrapping itself around the Ca{sup 2+} metal ion with, four oxygen and two nitrogen atoms and forms several five member chelate rings. The relative specific surface energies associated with the facets of the crystal determines the shape of the crystal. Scanning electron microscopy revealed the presence of hydroxyapatite nano strips with the range 50-100 nm in EDTA influenced HAP powders. Fourier transform-infrared spectroscopy (FT-IR) result combined with the X-ray diffraction (XRD) indicates the presence of amorphous hydroxyapatite (HAP) in the as-prepared material. X-ray patterns collected on the powder after heat-treatment at 1100 C for 2 h in air exhibits single phase of HAP. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. The structure of the Cepheid instability strip

    International Nuclear Information System (INIS)

    Fernie, J.D.

    1990-01-01

    About 100 classical Cepheids having color excesses on a homogeneous system with standard errors of 0.02 or less mag are used with the Feast-Walker period-luminosity-color relation to study the distribution of such stars in the instability strip. It is found that mean (B-V)mag is a better indicator of mean effective temperature than is mean B(i) - mean V(i)(i). The blue edge of the color-magnitude distribution is consistent with the theoretical blue edge for Y = 0.28 and Z = 0.02. Although the highest amplitude stars are found near the center of the period-color array, high- and low-amplitude stars can intermingle, and both kinds are to be found near the edges of the distribution. The same is true on the C-M array. Finally, it is pointed out that the Cepheids do not populate the instability strip uniformly if the red edge is taken to be parallel to the theoretical blue edge. Rather, the local instability region runs as a parallelogram in the C-M array from the theoretical blue edge upward and to the red. 24 refs

  7. Catalytic properties of niobium compounds

    International Nuclear Information System (INIS)

    Tanabe, K.; Iizuka, T.

    1983-04-01

    The catalytic activity and selectivity of niobium compounds including oxides, salts, organometallic compounds and others are outlined. The application of these compounds as catalysts to diversified reactions is reported. The nature and action of niobium catalysts are characteristic and sometimes anomalous, suggesting the necessity of basic research and the potential use as catalysts for important processes in the chemical industry. (Author) [pt

  8. Catalytic Decoupling of Quantum Information

    DEFF Research Database (Denmark)

    Majenz, Christian; Berta, Mario; Dupuis, Frédéric

    2017-01-01

    The decoupling technique is a fundamental tool in quantum information theory with applications ranging from quantum thermodynamics to quantum many body physics to the study of black hole radiation. In this work we introduce the notion of catalytic decoupling, that is, decoupling in the presence...... and quantum state merging, and leads to a resource theory of decoupling....

  9. Synthesis, spectroscopic characterization and catalytic oxidation ...

    Indian Academy of Sciences (India)

    were characterized by infrared, electronic, electron paramagnetic resonance ... The catalytic oxidation property of ruthenium(III) complexes were also ... cies at room temperature. ..... aldehyde part of Schiff base ligands, catalytic activ- ity of new ...

  10. Evaluation of silicon micro strip detectors with large read-out pitch

    International Nuclear Information System (INIS)

    Senyo, K.; Yamamura, K.; Tsuboyama, T.; Avrillon, S.; Asano, Y.; Bozek, A.; Natkaniec, Z.; Palka, H.; Rozanska, M.; Rybicki, K.

    1996-01-01

    For the development of the silicon micro-strip detector with the pitch of the readout strips as large as 250 μm on the ohmic side, we made samples with different structures. Charge collection was evaluated to optimize the width of implant strips, aluminum read-out strips, and/or the read-out scheme among strips. (orig.)

  11. New developments for localized adsorption

    International Nuclear Information System (INIS)

    Boudh-hir, M.E.

    1989-02-01

    Using the diagrammatic expansion, new developments for localized adsorption are found. It is proved that the correlations in the system, in the absence of the attractive site potential, and the periodicity of the sites play a fundamental role in the adsorption phenomena. 14 refs, 2 figs, 2 tabs

  12. Catalytic monolayer voltammetry and in situ scanning tunneling microscopy of copper nitrite reductase on cysteamine-modified Au(111) electrodes

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Welinder, A.C.; Hansen, Allan Glargaard

    2003-01-01

    electrochemical scanning tunneling microscopy (in situ STM) directly in aqueous acetate buffer, pH 6.0 has been used. High-resolution in situ STM shows that cysteamine packs into ordered domains with strip features of a periodic distance of 11.7 +/- 0.3 Angstrom. No voltammetric signals of the nitrite substrate...... on this surface could be detected. A strong cathodic catalytic wave appears in the presence of nitrite. The catalytic current follows a Michaelis-Menten pattern with a Michaelis constant of K-m approximate to 44 muM, which is close to the value for AxCuNiR in homogeneous solution. The apparent catalytic rate...

  13. Adsorption, hydrogenation and dehydrogenation of C2H on a CoCu bimetallic layer

    Science.gov (United States)

    Wu, Donghai; Yuan, Jinyun; Yang, Baocheng; Chen, Houyang

    2018-05-01

    In this paper, adsorption, hydrogenation and dehydrogenation of C2H on a single atomic layer of bimetallic CoCu were investigated using first-principles calculations. The CoCu bimetallic layer is formed by Cu replacement of partial Co atoms on the top layer of a Co(111) surface. Our adsorption and reaction results showed those sites, which have stronger adsorption energy of C2H, possess higher reactivity. The bimetallic layer possesses higher reactivity than either of the pure monometallic layer. A mechanism of higher reactivity of the bimetallic layer is proposed and identified, i.e. in the bimetallic catalyst, the catalytic performance of one component is promoted by the second component, and in our work, the catalytic performance of Co atoms in the bimetallic layer are improved by introducing Cu atoms, lowing the activation barrier of the reaction of C2H. The bimetallic layer could tune adsorption and reaction of C2H by modulating the ratio of Co and Cu. Results of adsorption energies and adsorption configurations reveal that C2H prefers to be adsorbed in parallel on both the pure Co metallic and CoCu bimetallic layers, and Co atoms in subsurface which support the metallic or bimetallic layer have little effect on C2H adsorption. For hydrogenation reactions, the products greatly depend on the concentration and initial positions of hydrogen atoms, and the C2H hydrogenation forming acetylene is more favorable than forming vinylidene in both thermodynamics and kinetics. This study would provide fundamental guidance for hydrocarbon reactions on Co-based and/or Cu-based bimetallic surface chemistry and for development of new bimetallic catalysts.

  14. Do repeated rumble strip hits improve driver alertness?

    NARCIS (Netherlands)

    Watling, C.N.; Akerstedt, T.; Kecklund, L.G.; Anund, A.

    2016-01-01

    Driving while sleepy is associated with increased crash risk. Rumble strips are designed to alert a sleepy or inattentive driver when they deviate outside their driving lane. The current study sought to examine the effects of repeated rumble strip hits on levels of physiological and subjective

  15. Metal films with imprinted nanostructures by template stripping

    DEFF Research Database (Denmark)

    Eriksen, René Lynge; Pors, Anders; Dreier, Jes

    We present a novel template stripping procedure for fabricating metal films with imprinted nanostructures. The basic idea is to deposit a gold film onto a nano-structured substrate and subsequently strip the film from the substrate surface thereby revealing imprinted nanostructures in the film...... result is a thin gold film with imprinted nano-cavities....

  16. Reforestation of strip-mined lands in West Virginia

    Science.gov (United States)

    H. Spencer Potter; Sidney Weitzman; George R., Jr. Trimble

    1951-01-01

    The early 1940's witnessed a striking increase in strip-mining throughout the eastern coal region. West Virginia, with its extensive coal resources, naturally was caught in the full current of this shift in mining methods. Today the raw gash on the hillside - almost infallibly the mark of a strip-mine operation - is a familiar sight in the State.

  17. Micro-strip sensors based on CVD diamond

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D' Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D. E-mail: dirk.meier@cern.ch; Mishina, M.; Moroni, L.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M

    2000-10-11

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition, we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation.

  18. Micro-strip sensors based on CVD Diamond

    CERN Document Server

    Adam, W; Bergonzo, P; Bertuccio, G; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Koeth, T W; Krammer, Manfred; Lo Giudice, A; Lü, R; MacLynne, L; Manfredotti, C; Meier, D; Mishina, M; Moroni, L; Oh, A; Pan, L S; Pernicka, Manfred; Peitz, A; Perera, L P; Pirollo, S; Procario, M; Riester, J L; Roe, S; Rousseau, L; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S R; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trischuk, W; Tromson, D; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Wetstein, M; White, C; Zeuner, W; Zoeller, M M

    2000-01-01

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation.

  19. Micro-strip sensors based on CVD diamond

    International Nuclear Information System (INIS)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L.S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J.L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.

    2000-01-01

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition, we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation

  20. Micro-strip sensors based on CVD diamond

    Science.gov (United States)

    Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K. K.; Gheeraert, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; mac Lynne, L.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L. S.; Pernicka, M.; Peitz, A.; Perera, L.; Pirollo, S.; Procario, M.; Riester, J. L.; Roe, S.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R. J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Wetstein, M.; White, C.; Zeuner, W.; Zoeller, M.; RD42 Collaboration

    2000-10-01

    In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition, we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation.

  1. Determination of residual stresses in roll compacted titanium strips

    CSIR Research Space (South Africa)

    Mothosi, KL

    2017-01-01

    Full Text Available residual stresses using x-ray diffraction (XRD) surface probing technique. Preliminary results were obtained for the surface residual stress at the center of the titanium strips for the 100 and 325 mesh strips rolled at 0.1 roll gap for 20 and 50 mm set...

  2. Stripping foils for the PSB H- injection system

    CERN Document Server

    Aiba, M; Goddard, B; Weterings, W

    2009-01-01

    Beam physics considerations for the stripping foil of the PSB H- injection system are described, including the arguments for the foil type, thickness, geometry and positioning. The foil performance considerations are described, including expected stripping efficiency, emittance growth, energy straggling, temperature and lifetime. The required movement ranges and tolerances are detailed, together with the assumptions used.

  3. Electrode/Dielectric Strip For High-Energy-Density Capacitor

    Science.gov (United States)

    Yen, Shiao-Ping S.

    1994-01-01

    Improved unitary electrode/dielectric strip serves as winding in high-energy-density capacitor in pulsed power supply. Offers combination of qualities essential for high energy density: high permittivity of dielectric layers, thinness, and high resistance to breakdown of dielectric at high electric fields. Capacitors with strip material not impregnated with liquid.

  4. Laser stripping of relativistic H- ions with practical considerations

    International Nuclear Information System (INIS)

    Tomlin, R.

    1995-12-01

    This paper describes laser stripping of H - ions. Some applications are suggested for HEP including stripping 2GeV ions circulating in an accelerator with radius 75 meters where laser meets ion head on in a three meter interaction region. The paper describes photoionizaton cross section, laser power calculation, and how to generate the 5 micrometer light

  5. Using Comic Strips as a Book Report Alternative

    Science.gov (United States)

    Reading Teacher, 2012

    2012-01-01

    Comic strips are great to share with parents, younger students, and peers. This article presents an activity where students use a six-paneled comic strip to summarize a story. This activity allows for multiple interpretations and enhances comprehension by drawing attention to story elements.

  6. Quality Tests of Double-Sided Silicon Strip Detectors

    CERN Document Server

    Cambon, T; CERN. Geneva; Fintz, P; Guillaume, G; Jundt, F; Kuhn, C; Lutz, Jean Robert; Pagès, P; Pozdniakov, S; Rami, F; Sparavec, K; Dulinski, W; Arnold, L

    1997-01-01

    The quality of the SiO2 insulator (AC coupling between metal and implanted strips) of double-sided Silicon strip detectors has been studied by using a probe station. Some tests performed on 23 wafers are described and the results are discussed. Remark This note seems to cause problems with ghostview but it can be printed without any problem.

  7. Effects of γ-irradiation and ageing on surface and catalytic properties of nano-sized Cu O/Mg O system

    International Nuclear Information System (INIS)

    El-Molla, S. A.; Ismail, S. A.; Ibrahim, M. M.

    2011-01-01

    0.2 Cu O/Mg O system prepared by impregnation method was calcined at 350 and 450 C. The effects of γ-rays (0.2-1.6 MGy) on its structure, surface and catalytic properties were investigated by using XRD, N 2 -adsorption at -196 C and catalytic conversion of isopropanol at 150-275 C using a flow technique. The results revealed that the investigated solids consisted of nano-sized Mg O as a major phase besides Cu O and trace amount of Cu 2 O. γ-Irradiation of the solids investigated exerted measurable changes in their surface and catalytic properties dependent on the calcination temperature and dose of irradiation. The catalysts investigated acted as active dehydrogenation solids. The five years-ageing of different solids showed limited changes of their surface and catalytic properties indicating a good catalytic stability of the irradiated prepared solids. (Author)

  8. Effects of {gamma}-irradiation and ageing on surface and catalytic properties of nano-sized Cu O/Mg O system

    Energy Technology Data Exchange (ETDEWEB)

    El-Molla, S. A. [Ain Shams University, Faculty of Education, Chemistry Deparment, Roxy, Heliopolis, 11757 Cairo (Egypt); Ismail, S. A.; Ibrahim, M. M., E-mail: saharelmolla@yahoo.com [National Center for Radiation Research and Technology, Nasr City, P.O. Box 29, 11731 Cairo (Egypt)

    2011-07-01

    0.2 Cu O/Mg O system prepared by impregnation method was calcined at 350 and 450 C. The effects of {gamma}-rays (0.2-1.6 MGy) on its structure, surface and catalytic properties were investigated by using XRD, N{sub 2}-adsorption at -196 C and catalytic conversion of isopropanol at 150-275 C using a flow technique. The results revealed that the investigated solids consisted of nano-sized Mg O as a major phase besides Cu O and trace amount of Cu{sub 2}O. {gamma}-Irradiation of the solids investigated exerted measurable changes in their surface and catalytic properties dependent on the calcination temperature and dose of irradiation. The catalysts investigated acted as active dehydrogenation solids. The five years-ageing of different solids showed limited changes of their surface and catalytic properties indicating a good catalytic stability of the irradiated prepared solids. (Author)

  9. ZVI (Fe0) desalination: catalytic partial desalination of saline aquifers

    Science.gov (United States)

    Antia, David D. J.

    2018-05-01

    Globally, salinization affects between 100 and 1000 billion m3 a-1 of irrigation water. The discovery that zero valent iron (ZVI, Fe0) could be used to desalinate water (using intra-particle catalysis in a diffusion environment) raises the possibility that large-scale in situ desalination of aquifers could be undertaken to support agriculture. ZVI desalination removes NaCl by an adsorption-desorption process in a multi-stage cross-coupled catalytic process. This study considers the potential application of two ZVI desalination catalyst types for in situ aquifer desalination. The feasibility of using ZVI catalysts when placed in situ within an aquifer to produce 100 m3 d-1 of partially desalinated water from a saline aquifer is considered.

  10. Mechanism for enhanced degradation of clofibric acid in aqueous by catalytic ozonation over MnOx/SBA-15

    International Nuclear Information System (INIS)

    Sun, Qiangqiang; Wang, Yu; Li, Laisheng; Bing, Jishuai; Wang, Yingxin; Yan, Huihua

    2015-01-01

    Highlights: • Clofibric acid (CA) is efficiently mineralized by O 3 /MnO x /SBA-15. • Adsorption of CA and its intermediates on MnO x /SBA-15 is proved unimportant. • Initiation of hydroxyl radicals (·OH) is enhanced in O 3 /MnO x /SBA-15. • Uniformly distributed MnO x accounts for the high activity of MnO x /SBA-15. • Degradation routes of CA in ozonation alone and catalytic ozonation are proposed. - Abstract: Comparative experiments were conducted to investigate the catalytic ability of MnO x /SBA-15 for the ozonation of clofibric acid (CA) and its reaction mechanism. Compared with ozonation alone, the degradation of CA was barely enhanced, while the removal of TOC was significantly improved by catalytic ozonation (O 3 /MnO x /SBA-15). Adsorption of CA and its intermediates by MnO x /SBA-15 was proved unimportant in O 3 /MnO x /SBA-15 due to the insignificant adsorption of CA and little TOC variation after ceasing ozone in stopped-flow experiment. The more remarkably inhibition effect of sodium bisulfite (NaHSO 3 ) on the removal of TOC in catalytic ozonation than in ozonation alone elucidated that MnO x /SBA-15 facilitated the generation of hydroxyl radicals (·OH), which was further verified by electron spin-resonance spectroscopy (ESR). Highly dispersed MnO x on SBA-15 were believed to be the main active component in MnO x /SBA-15. Some intermediates were indentified and different degradation routes of CA were proposed in both ozonation alone and catalytic ozonation. The amounts of small molecular carboxylic acids (i.e., formic acid (FA), acetic acid (AA) and oxalic acid (OA)) generated in catalytic ozonation were lower than in ozonation alone, resulting from the generation of more ·OH

  11. Optical fiber cable chemical stripping fixture

    Science.gov (United States)

    Kolasinski, John R. (Inventor); Coleman, Alexander M. (Inventor)

    1995-01-01

    An elongated fixture handle member is connected to a fixture body member with both members having interconnecting longitudinal central axial bores for the passage of an optical cable therethrough. The axial bore of the fixture body member, however, terminates in a shoulder stop for the outer end of a jacket of the optical cable covering both an optical fiber and a coating therefor, with an axial bore of reduced diameter continuing from the shoulder stop forward for a predetermined desired length to the outer end of the fixture body member. A subsequent insertion of the fixture body member including the above optical fiber elements into a chemical stripping solution results in a softening of the exposed external coating thereat which permits easy removal thereof from the optical fiber while leaving a desired length coated fiber intact within the fixture body member.

  12. Dynamic underground stripping. Innovative technology summary report

    International Nuclear Information System (INIS)

    1995-04-01

    Dynamic Underground Stripping (DUS) is a combination of technologies targeted to remediate soil and ground water contaminated with organic compounds. DUS is effective both above and below the water table and is especially well suited for sites with interbedded sand and clay layers. The main technologies comprising DUS are steam injection at the periphery of a contaminated area to heat permeable subsurface areas, vaporize volatile compounds bound to the soil, and drive contaminants to centrally located vacuum extraction wells; electrical heating of less permeable sediments to vaporize contaminants and drive them into the steam zone; and underground imaging such as Electrical Resistance Tomography to delineate heated areas to ensure total cleanup and process control. A full-scale demonstration was conducted on a gasoline spill site at Lawrence Livermore National Laboratory in Livermore, California from November 1992 through December 1993

  13. Digital autoradiography using silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Overdick, M.

    1998-05-01

    Spatially resolving radiation detection systems operating in real time can be used to acquire autoradiographic images. An overview over alternatives to traditional autoradiography is given and the special features of these filmless methods are discussed. On this basis the design of a system for digital autoradiography using silicon strip detectors is presented. Special emphasis is put on the physical background of the detection process in the semiconductor and on the self-triggering read-out technique. The practical performance of the system is analyzed with respect to energy and spatial resolution. This analysis is complemented by case studies from cell biology (especially electrophoresis), botany and mineralogy. Also the results from a time-resolved autoradiographic experiment are presented. (orig.) 80 refs.

  14. Coplanar strips for Josephson voltage standard circuits

    International Nuclear Information System (INIS)

    Schubert, M.; May, T.; Wende, G.; Fritzsch, L.; Meyer, H.-G.

    2001-01-01

    We present a microwave circuit for Josephson voltage standards. Here, the Josephson junctions are integrated in a microwave transmission line designed as coplanar strips (CPS). The new layout offers the possibility of achieving a higher scale of integration and to considerably simplify the fabrication technology. The characteristic impedance of the CPS is about 50 Ω, and this should be of interest for programmable Josephson voltage standard circuits with SNS or SINIS junctions. To demonstrate the function of the microwave circuit design, conventional 10 V Josephson voltage standard circuits with 17000 Nb/AlO x /Nb junctions were prepared and tested. Stable Shapiro steps at the 10 V level were generated. Furthermore, arrays of 1400 SINIS junctions in this microwave layout exhibited first-order Shapiro steps. Copyright 2001 American Institute of Physics

  15. Silicon strip detectors for the ATLAS upgrade

    CERN Document Server

    Gonzalez Sevilla, S; The ATLAS collaboration

    2011-01-01

    The Large Hadron Collider at CERN will extend its current physics program by increasing the peak luminosity by one order of magnitude. For ATLAS, one of the two general-purpose experiments of the LHC, an upgrade scenario will imply the complete replacement of its internal tracker due to the harsh conditions in terms of particle rates and radiation doses. New radiation-hard prototype n-in-p silicon sensors have been produced for the short-strip region of the future ATLAS tracker. The sensors have been irradiated up to the fluences expected in the high-luminous LHC collider. This paper summarizes recent results on the performance of the irradiated n-in-p detectors.

  16. Square-wave stripping voltammetric determination of caffeic acid on electrochemically reduced graphene oxide-Nafion composite film.

    Science.gov (United States)

    Filik, Hayati; Çetintaş, Gamze; Avan, Asiye Aslıhan; Aydar, Sevda; Koç, Serkan Naci; Boz, İsmail

    2013-11-15

    An electrochemical sensor composed of Nafion-graphene nanocomposite film for the voltammetric determination of caffeic acid (CA) was studied. A Nafion graphene oxide-modified glassy carbon electrode was fabricated by a simple drop-casting method and then graphene oxide was electrochemically reduced over the glassy carbon electrode. The electrochemical analysis method was based on the adsorption of caffeic acid on Nafion/ER-GO/GCE and then the oxidation of CA during the stripping step. The resulting electrode showed an excellent electrocatalytical response to the oxidation of caffeic acid (CA). The electrochemistry of caffeic acid on Nafion/ER-GO modified glassy carbon electrodes (GCEs) were studied by cyclic voltammetry and square-wave adsorption stripping voltammetry (SW-AdSV). At optimized test conditions, the calibration curve for CA showed two linear segments: the first linear segment increased from 0.1 to 1.5 and second linear segment increased up to 10 µM. The detection limit was determined as 9.1×10(-8) mol L(-1) using SW-AdSV. Finally, the proposed method was successfully used to determine CA in white wine samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Mechanism for enhanced degradation of clofibric acid in aqueous by catalytic ozonation over MnOx/SBA-15.

    Science.gov (United States)

    Sun, Qiangqiang; Wang, Yu; Li, Laisheng; Bing, Jishuai; Wang, Yingxin; Yan, Huihua

    2015-04-09

    Comparative experiments were conducted to investigate the catalytic ability of MnO(x)/SBA-15 for the ozonation of clofibric acid (CA) and its reaction mechanism. Compared with ozonation alone, the degradation of CA was barely enhanced, while the removal of TOC was significantly improved by catalytic ozonation (O3/MnO(x)/SBA-15). Adsorption of CA and its intermediates by MnO(x)/SBA-15 was proved unimportant in O3/MnO(x)/SBA-15 due to the insignificant adsorption of CA and little TOC variation after ceasing ozone in stopped-flow experiment. The more remarkably inhibition effect of sodium bisulfite (NaHSO3) on the removal of TOC in catalytic ozonation than in ozonation alone elucidated that MnO(x)/SBA-15 facilitated the generation of hydroxyl radicals (OH), which was further verified by electron spin-resonance spectroscopy (ESR). Highly dispersed MnO(x) on SBA-15 were believed to be the main active component in MnO(x)/SBA-15. Some intermediates were indentified and different degradation routes of CA were proposed in both ozonation alone and catalytic ozonation. The amounts of small molecular carboxylic acids (i.e., formic acid (FA), acetic acid (AA) and oxalic acid (OA)) generated in catalytic ozonation were lower than in ozonation alone, resulting from the generation of more OH. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Strip specimen tests for pipeline materials and girth welds

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, William C. [Edison Welding Institute (EWI), Columbus, Ohio (United States)

    2009-07-01

    Strip specimen testing of pipeline materials has been widely applied as a method of getting data relevant to the performance of pipelines under axial direction loading. Comparisons of strip specimen against smaller standard tests (round tensile bar, fracture toughness specimens, polished round bars) and against full-scale or large-scale testing will be explored. Data from early-generation pipe welds from the 1920's to the 1940's to the most recent materials for offshore reeled pipe will be used for examples. Strip samples can provide full thickness information to take account of varying material properties or imperfection distribution through the thickness. Strip samples can also accommodate measurement of effects of the original surface finish or weld surface shape. Strip samples have more design flexibility than standard tests, but must be designed to limit stress concentrations and effects of local bending. (author)

  19. Eddy current distribution and lift force for finite MAGLEV strips

    Energy Technology Data Exchange (ETDEWEB)

    Atherton, D L; Eastham, A R; Fombrun, C; Chong, M

    1974-07-01

    The transverse distribution of induced eddy currents across a flat conducing strip of finite width, due to a rectangular dc magnet moving above it, was modelled experimentally, and was compared with that calculated for an infinite sheet. The electrodynamic suspension was simulated by means of a stationary ac-excited copper magnet suspended above an aluminum strip, and the induced surface current density was measured by a voltage pickup probe connected to a lock-in amplifier. The effect of reducing strip width is examined and shown to produce high current densities close to the edges. These results are related to the variation of lift force with strip width, determined by impedance modelling. A slight enhancement of lift is evident for intermediate strip widths.

  20. Evaluation of anatomy comic strips for further production and applications

    Science.gov (United States)

    Shin, Dong Sun; Kim, Dae Hyun; Park, Jin Seo; Jang, Hae Gwon

    2013-01-01

    The corresponding author of the study has been sketching comic strips to explain anatomy in a humorous manner. All the anatomy comic strips, including those in Korean (650 episodes) and English (451 episodes), can be viewed on the homepage (http://anatomy.co.kr). Such comic strips were created with the aim of assisting medical students. However, their impact was unknown, and therefore, we surveyed the students' responses. We noted that anatomy grades were better in the students who read the comic strips. The comics helped the trainees chat with individuals with and without a medical background. The authors also considered comments on the problems with the comic strips and attempted to find solutions. The episodes are being currently used and further produced for educational purposes. To support this effort, the readers' valuable opinions will be continuously collected and assessed. PMID:24179697

  1. Evaluation of anatomy comic strips for further production and applications.

    Science.gov (United States)

    Shin, Dong Sun; Kim, Dae Hyun; Park, Jin Seo; Jang, Hae Gwon; Chung, Min Suk

    2013-09-01

    The corresponding author of the study has been sketching comic strips to explain anatomy in a humorous manner. All the anatomy comic strips, including those in Korean (650 episodes) and English (451 episodes), can be viewed on the homepage (http://anatomy.co.kr). Such comic strips were created with the aim of assisting medical students. However, their impact was unknown, and therefore, we surveyed the students' responses. We noted that anatomy grades were better in the students who read the comic strips. The comics helped the trainees chat with individuals with and without a medical background. The authors also considered comments on the problems with the comic strips and attempted to find solutions. The episodes are being currently used and further produced for educational purposes. To support this effort, the readers' valuable opinions will be continuously collected and assessed.

  2. Catalytic process for tritium exchange reaction

    International Nuclear Information System (INIS)

    Hansoo Lee; Kang, H.S.; Paek, S.W.; Hongsuk Chung; Yang Geun Chung; Sook Kyung Lee

    2001-01-01

    The catalytic activities for a hydrogen isotope exchange were measured through the reaction of a vapor and gas mixture. The catalytic activity showed to be comparable with the published data. Since the gas velocity is relatively low, the deactivation was not found clearly during the 5-hour experiment. Hydrogen isotope transfer experiments were also conducted through the liquid phase catalytic exchange reaction column that consisted of a catalytic bed and a hydrophilic bed. The efficiencies of both the catalytic and hydrophilic beds were higher than 0.9, implying that the column performance was excellent. (author)

  3. Analysis of heterogeneous oxygen exchange and fuel oxidation on the catalytic surface of perovskite membranes

    KAUST Repository

    Hong, Jongsup

    2013-10-01

    The catalytic kinetics of oxygen surface exchange and fuel oxidation for a perovskite membrane is investigated in terms of the thermodynamic state in the immediate vicinity of or on the membrane surface. Perovskite membranes have been shown to exhibit both oxygen perm-selectivity and catalytic activity for hydrocarbon conversion. A fundamental description of their catalytic surface reactions is needed. In this study, we infer the kinetic parameters for heterogeneous oxygen surface exchange and catalytic fuel conversion reactions, based on permeation rate measurements and a spatially resolved physical model that incorporates detailed chemical kinetics and transport in the gas-phase. The conservation equations for surface and bulk species are coupled with those of the gas-phase species through the species production rates from surface reactions. It is shown that oxygen surface exchange is limited by dissociative/associative adsorption/desorption of oxygen molecules onto/from the membrane surface. On the sweep side, while the catalytic conversion of methane to methyl radical governs the overall surface reactions at high temperature, carbon monoxide oxidation on the membrane surface is dominant at low temperature. Given the sweep side conditions considered in ITM reactor experiments, gas-phase reactions also play an important role, indicating the significance of investigating both homogeneous and heterogeneous chemistry and their coupling when examining the results. We show that the local thermodynamic state at the membrane surface should be considered when constructing and examining models of oxygen permeation and heterogeneous chemistry. © 2013 Elsevier B.V.

  4. Analysis of heterogeneous oxygen exchange and fuel oxidation on the catalytic surface of perovskite membranes

    KAUST Repository

    Hong, Jongsup; Kirchen, Patrick; Ghoniem, Ahmed F.

    2013-01-01

    The catalytic kinetics of oxygen surface exchange and fuel oxidation for a perovskite membrane is investigated in terms of the thermodynamic state in the immediate vicinity of or on the membrane surface. Perovskite membranes have been shown to exhibit both oxygen perm-selectivity and catalytic activity for hydrocarbon conversion. A fundamental description of their catalytic surface reactions is needed. In this study, we infer the kinetic parameters for heterogeneous oxygen surface exchange and catalytic fuel conversion reactions, based on permeation rate measurements and a spatially resolved physical model that incorporates detailed chemical kinetics and transport in the gas-phase. The conservation equations for surface and bulk species are coupled with those of the gas-phase species through the species production rates from surface reactions. It is shown that oxygen surface exchange is limited by dissociative/associative adsorption/desorption of oxygen molecules onto/from the membrane surface. On the sweep side, while the catalytic conversion of methane to methyl radical governs the overall surface reactions at high temperature, carbon monoxide oxidation on the membrane surface is dominant at low temperature. Given the sweep side conditions considered in ITM reactor experiments, gas-phase reactions also play an important role, indicating the significance of investigating both homogeneous and heterogeneous chemistry and their coupling when examining the results. We show that the local thermodynamic state at the membrane surface should be considered when constructing and examining models of oxygen permeation and heterogeneous chemistry. © 2013 Elsevier B.V.

  5. Catalytic Fast Pyrolysis: A Review

    Directory of Open Access Journals (Sweden)

    Theodore Dickerson

    2013-01-01

    Full Text Available Catalytic pyrolysis is a promising thermochemical conversion route for lignocellulosic biomass that produces chemicals and fuels compatible with current, petrochemical infrastructure. Catalytic modifications to pyrolysis bio-oils are geared towards the elimination and substitution of oxygen and oxygen-containing functionalities in addition to increasing the hydrogen to carbon ratio of the final products. Recent progress has focused on both hydrodeoxygenation and hydrogenation of bio-oil using a variety of metal catalysts and the production of aromatics from bio-oil using cracking zeolites. Research is currently focused on developing multi-functional catalysts used in situ that benefit from the advantages of both hydrodeoxygenation and zeolite cracking. Development of robust, highly selective catalysts will help achieve the goal of producing drop-in fuels and petrochemical commodities from wood and other lignocellulosic biomass streams. The current paper will examine these developments by means of a review of existing literature.

  6. Study of inter-strip gap effects and efficiency for full energy detection of double sided silicon strip detectors

    International Nuclear Information System (INIS)

    Fisichella, M.; Forneris, J.; Grassi, L.

    2015-01-01

    We performed a characterization of Double Sided Silicon Strip Detectors (DSSSD) with the aim to carry out a systematic study of the inter-strip effects on the energy measurement of charged particles. The dependence of the DSSSD response on ion, energy and applied bias has been investigated. (author)

  7. Adsorption Desalination: A Novel Method

    KAUST Repository

    Ng, Kim Choon

    2010-11-15

    The search for potable water for quenching global thirst remains a pressing concern throughout many regions of the world. The demand for new and sustainable sources and the associated technologies for producing fresh water are intrinsically linked to the solving of potable water availability and hitherto, innovative and energy efficient desalination methods seems to be the practical solutions. Quenching global thirst by adsorption desalination is a practical and inexpensive method of desalinating the saline and brackish water to produce fresh water for agriculture irrigation, industrial, and building applications. This chapter provides a general overview of the adsorption fundamentals in terms of adsorption isotherms, kinetics, and heat of adsorption. It is then being more focused on the principles of thermally driven adsorption desalination methods. The recent developments of adsorption desalination plants and the effect of operating conditions on the system performance in terms of specific daily water production and performance ratio are presented. Design of a large commercial adsorption desalination plant is also discussed herein.

  8. Catalytic processes for cleaner fuels

    International Nuclear Information System (INIS)

    Catani, R.; Marchionna, M.; Rossini, S.

    1999-01-01

    More stringent limitations on vehicle emissions require different measurement: fuel reformulation is one of the most important and is calling for a noticeable impact on refinery assets. Composition rangers of the future fuels have been defined on a time scale. In this scenario the evolution of catalytic technologies becomes a fundamental tool for allowing refinery to reach the fixed-by-law targets. In this paper, the refinery process options to meet each specific requirements of reformulated fuels are surveyed [it

  9. Highly Selective Synthesis of Catalytically Active Monodisperse Rhodium Nanocubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Grass, M.E.; Kuhn, J.N.; Tao, F.; Habas, S.E.; Huang, W.; Yang, P.; Somorjai, G.A.

    2009-02-21

    Synthesis of monodisperse and shape-controlled colloidal inorganic nanocrystals (NCs) is of increasing scientific interest and technological significance. Recently, shape control of Pt, Pd, Ag, Au, and Rh NCs has been obtained by tuning growth kinetics in various solution-phase approaches, including modified polyol methods, seeded growth by polyol reduction, thermolysis of organometallics, and micelle techniques. Control of reduction kinetics of the noble metal precursors and regulation of the relative growth rates of low-index planes (i.e. {l_brace}100{r_brace} and {l_brace}111{r_brace}) via selective adsorption of selected chemical species are two keys for achieving shape modification of noble metal NCs. One application for noble metal NCs of well-defined shape is in understanding how NC faceting (determines which crystallographic planes are exposed) affects catalytic performance. Rh NCs are used in many catalytic reactions, including hydrogenation, hydroformylation, hydrocarbonylation, and combustion reactions. Shape manipulation of Rh NCs may be important in understanding how faceting on the nanoscale affects catalytic properties, but such control is challenging and there are fewer reports on the shape control of Rh NCs compared to other noble metals. Xia and coworkers obtained Rh multipods exhibiting interesting surface plasmonic properties by a polyol approach. The Somorjai and Tilley groups synthesized crystalline Rh multipods, cubes, horns and cuboctahedra, via polyol seeded growth. Son and colleagues prepared catalytically active monodisperse oleylamine-capped tetrahedral Rh NCs for the hydrogenation of arenes via an organometallic route. More recently, the Somorjai group synthesized sizetunable monodisperse Rh NCs using a one-step polyol technique. In this Communication, we report the highly selective synthesis of catalytically active, monodisperse Rh nanocubes of < 10 nm by a seedless polyol method. In this approach, Br{sup -} ions from trimethyl

  10. Microstructural research on hot strips of low carbon steel produced by a compact strip production line under different thermal histories

    International Nuclear Information System (INIS)

    Yu Hao; Chen Qixiang; Kang Yonglin; Sun Yi

    2005-01-01

    Coupons with the same composition and thickness (4.0 mm nominal gauge) obtained from hot strips of low carbon steel underwent a series of investigations to analyze the microstructural characteristics and mechanisms responsible for their differences in mechanical properties. Two different industrial technologies were adopted, although the strips used in this research were produced on the same Compact Strip Production (CSP) line. One of the strips was produced with a routine γ→α CSP thermal history, but the other with a γ→α→γ* conventional thermal history. The only difference between them was that one technology had a α→γ* thermal history. Different specimens of both types of strips were prepared for metallographic observation, tensile tests, electron back-scattered diffraction tests and positron annihilation technique tests. Experimental results showed that the differences in mechanical properties could be ascribed to dissimilarities not only in the grain size and textural components but also in dislocation density

  11. Adsorption facility and adsorption vessel for radioactive carbon dioxide

    International Nuclear Information System (INIS)

    Harashina, Heihachi; Miwa, Keiichi; Kobayashi, Takeo.

    1992-01-01

    If 14 CO 2 gas-containing gases to be adsorbed are pressurized and sent to a packaging adsorption means, CO 2 ingredient in the gases to be adsorbed is adsorbed or absorbed, and remaining gases are passed through and sent out to downstream. CO 2 adsorption or absorption of the packaging adsorption means is judged by monitoring the state of the remaining gases, and if it is normal, remaining gases are sent further to downstream and processed. If abnormality is found, a gas feedback system is operated, and CO 2 removing gas is sent again to the packaging adsorption means, in which CO 2 gases are adsorbed or absorbed again repeatingly. With such procedures, in a case where C 14 nuclides having a long half decay time are supplied in the form of 14 CO 2 gas, they are efficiently adsorbed or absorbed in the packaging system to improve removing and storing property of 14 C nuclides. (T.M.)

  12. Carbon nanomaterials for gas adsorption

    CERN Document Server

    Terranova, Maria Letizia

    2012-01-01

    Research in adsorption of gases by carbon nanomaterials has experienced considerable growth in recent years, with increasing interest for practical applications. Many research groups are now producing or using such materials for gas adsorption, storage, purification, and sensing. This book provides a selected overview of some of the most interesting scientific results regarding the outstanding properties of carbon nanomaterials for gas adsorption and of interest both for basic research and technological applications. Topics receiving special attention in this book include storage of H, purific

  13. Hydrogen purification by periodic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Barg, Christian; Secchi, Argimiro R.; Trierweiler, Jorge O. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica]. E-mail: cbarg@enq.ufrgs.br; arge@enq.ufrgs.br; jorge@enq.ufrgs.br

    2000-07-01

    The periodic adsorption processes have been widely used for industrial applications, mainly because it spends less energy than the usual gas separation processes, like the cryogenic distillation. The largest commercial application of periodic adsorption processes is the pressure swing adsorption (PSA) applied to hydrogen purification. Although its wide use in the chemical and petrochemical industry, there are no reports in the open literature about complete modeling studies of a complex commercial unit, with multiple adsorbents and multiple beds and several feed components. This study has as objective the modeling, optimization and dynamical analysis of an industrial PSA unit for hydrogen purification. (author)

  14. Unique reactivity of Fe nanoparticles-defective graphene composites toward NH x (x = 0, 1, 2, 3) adsorption: A first-principles study

    KAUST Repository

    Liu, Xin

    2012-01-01

    We investigated the electronic structure of Fe nanoparticle-graphene composites and the impact of the interfacial interaction on NH x (x = 0, 1, 2, 3) adsorption by first-principles based calculations. We found that Fe 13 nanoparticles can be stabilized by the sp 2 dangling bonds on single vacancy graphene substrate with a binding energy up to -7.07 eV. This interaction not only deformed the carbon atoms around the defect and gave rise to the stability of the Fe nanoparticle against sintering, but also had significant impact on the adsorption of NH x that is related to the catalytic performance of these composites in NH 3 decomposition. Doping of the single vacancy graphene with N or B can finely tune the adsorption of NH x. Further analysis revealed that the calculated adsorption energies of NH x on these composites correlated well with the shift of the average d-band center of the Fe nanoparticles and they were around the peak of the activity-adsorption energy curve for NH 3 decomposition catalysts, especially when doped with B. The optimal adsorption of NH x on Fe nanoparticles deposited on boron-doped defective graphene suggests the possible high stability and superior catalytic performance of these composites in the low-temperature catalytic decomposition of NH 3. This journal is © 2012 the Owner Societies.

  15. New Concept of Cultivation Using Limited Strip-Tillage with Strip Shallow Irrigation

    Directory of Open Access Journals (Sweden)

    Yazid Ismi Intara

    2014-04-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE Dry land is one of land resources which potentially used for food crop cultivation, especially in the areas which have light to medium technical obstacles. The development of technology to improve soil quality in marginal lands to be productive lands is still widely open for agricultural development in Indonesia. Rooting medium quality can be improved by changing soil tillage method and observing the proper crop irrigation technology. It can be the solution for crop cultivation in clay loam soil. This study aimed to obtain water movement model in a minimally-tilled clay soil with strip shallow irrigation. The concept is limited soil-tillage with strip shallow irrigation method, water supply technique, and crop water requirement. Method used in this study includes developing water movement model (software development in a minimally-tilled clay soil with subsurface irrigation. In the final stages, research also conducted water movement analysis testing apparatus in the laboratory, field validation of the subsurface irrigation performance, and cultivation technique testing to chili pepper growth (Capsicum annuumL.. The development of water movement simulation on a limited strip-tillage with subsurface irrigation uses the concept to quantify the amount of water in the soil. The analysis of movement pattern was demonstrated on contour patterns. It showed that the wetting process can reach depth zone – 5 cm to the rooting zone. It was an important discovery on the development of minimum stripe tillage soil with subsurface irrigation. Specifically, it can be concluded that: the result of fitting by eyes to diffusivity graphic and water content obtained the required parameter values for soil physical properties. It was then simulated on horizontal water movement model on a minimum strip-tillage with strip shallow irrigation /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso

  16. Catalytic Reduction of NO and NOx Content in Tobacco Smoke

    Directory of Open Access Journals (Sweden)

    Cvetkovic N

    2014-12-01

    Full Text Available In order to reduce the nitric oxide (NO and nitrogen oxides (NO content in mainstream tobacco smoke, a new class of catalyst based on Cu-ZSM-5 zeolite has been synthesized. The effectiveness of the new catalyst (degree of reduction and specific catalytic ability was tested both by adding Cu-ZSM-5 zeolite directly to the tobacco blend and by addition to the filter. We have determined that adding the catalyst to the tobacco blend does not cause any changes in the physical, chemical or organoleptic properties of the cigarette blend. But, the addition reduces the yield of nitrogen oxides while having no influence on nicotine and “tar” content in the tobacco smoke of the modified blend. The catalyst addition increases the static burning rate (SBR. The changes in the quantity of NO and NOmay be explained by changes in burning conditions due to the increase of Oobtained from catalytic degradation of NO and NO, and adsorptive and diffusive properties of the catalyst. The changes in mainstream smoke analytes are also given on a puff-by-puff basis.

  17. Protein Adsorption in Three Dimensions

    Science.gov (United States)

    Vogler, Erwin A.

    2011-01-01

    Recent experimental and theoretical work clarifying the physical chemistry of blood-protein adsorption from aqueous-buffer solution to various kinds of surfaces is reviewed and interpreted within the context of biomaterial applications, especially toward development of cardiovascular biomaterials. The importance of this subject in biomaterials surface science is emphasized by reducing the “protein-adsorption problem” to three core questions that require quantitative answer. An overview of the protein-adsorption literature identifies some of the sources of inconsistency among many investigators participating in more than five decades of focused research. A tutorial on the fundamental biophysical chemistry of protein adsorption sets the stage for a detailed discussion of the kinetics and thermodynamics of protein adsorption, including adsorption competition between two proteins for the same adsorbent immersed in a binary-protein mixture. Both kinetics and steady-state adsorption can be rationalized using a single interpretive paradigm asserting that protein molecules partition from solution into a three-dimensional (3D) interphase separating bulk solution from the physical-adsorbent surface. Adsorbed protein collects in one-or-more adsorbed layers, depending on protein size, solution concentration, and adsorbent surface energy (water wettability). The adsorption process begins with the hydration of an adsorbent surface brought into contact with an aqueous-protein solution. Surface hydration reactions instantaneously form a thin, pseudo-2D interface between the adsorbent and protein solution. Protein molecules rapidly diffuse into this newly-formed interface, creating a truly 3D interphase that inflates with arriving proteins and fills to capacity within milliseconds at mg/mL bulk-solution concentrations CB. This inflated interphase subsequently undergoes time-dependent (minutes-to-hours) decrease in volume VI by expulsion of either-or-both interphase water and

  18. Strong Selective Adsorption of Polymers.

    Science.gov (United States)

    Ge, Ting; Rubinstein, Michael

    2015-06-09

    A scaling theory is developed for selective adsorption of polymers induced by the strong binding between specific monomers and complementary surface adsorption sites. By "selective" we mean specific attraction between a subset of all monomers, called "sticky", and a subset of surface sites, called "adsorption sites". We demonstrate that, in addition to the expected dependence on the polymer volume fraction ϕ bulk in the bulk solution, selective adsorption strongly depends on the ratio between two characteristic length scales, the root-mean-square distance l between neighboring sticky monomers along the polymer, and the average distance d between neighboring surface adsorption sites. The role of the ratio l / d arises from the fact that a polymer needs to deform to enable the spatial commensurability between its sticky monomers and the surface adsorption sites for selective adsorption. We study strong selective adsorption of both telechelic polymers with two end monomers being sticky and multisticker polymers with many sticky monomers between sticky ends. For telechelic polymers, we identify four adsorption regimes at l / d 1, we expect that the adsorption layer at exponentially low ϕ bulk consists of separated unstretched loops, while as ϕ bulk increases the layer crosses over to a brush of extended loops with a second layer of weakly overlapping tails. For multisticker chains, in the limit of exponentially low ϕ bulk , adsorbed polymers are well separated from each other. As l / d increases, the conformation of an individual polymer changes from a single-end-adsorbed "mushroom" to a random walk of loops. For high ϕ bulk , adsorbed polymers at small l / d are mushrooms that cover all the adsorption sites. At sufficiently large l / d , adsorbed multisticker polymers strongly overlap. We anticipate the formation of a self-similar carpet and with increasing l / d a two-layer structure with a brush of loops covered by a self-similar carpet. As l / d exceeds the

  19. Catalytic wet air oxidation of chlorophenols over supported ruthenium catalysts

    International Nuclear Information System (INIS)

    Li Ning; Descorme, Claude; Besson, Michele

    2007-01-01

    A series of noble metal (Pt, Pd, Ru) loaded zirconia catalysts were evaluated in the catalytic wet air oxidation (CWAO) of mono-chlorophenols (2-CP, 3-CP, 4-CP) under relatively mild reaction conditions. Among the investigated noble metals, Ru appeared to be the best to promote the CWAO of CPs as far as incipient-wetness impregnation was used to prepare all the catalysts. The position of the chlorine substitution on the aromatic ring was also shown to have a significant effect on the CP reactivity in the CWAO over 3 wt.% Ru/ZrO 2 . 2-CP was relatively easier to degradate compared to 3-CP and 4-CP. One reason could be the higher adsorption of 2-CP on the catalyst surface. Further investigations suggested that 3 wt.% Ru/ZrO 2 is a very efficient catalyst in the CWAO of 2-CP as far as high 2-CP conversion and TOC abatement could still be reached at even lower temperature (393 K) and lower total pressure (3 MPa). Additionally, the conversion of 2-CP was demonstrated to increase with the initial pH of the 2-CP solution. The dechlorination reaction is promoted at higher pH. In all cases, the adsorption of the reactants and the reaction intermediates was shown to play a major role. All parameters that would control the molecule speciation in solution or the catalyst surface properties would have a key effect

  20. Water adsorption on goethite: Application of multilayer adsorption models

    Science.gov (United States)

    Hatch, C. D.; Tumminello, R.; Meredith, R.

    2016-12-01

    Adsorbed water on the surface of atmospheric mineral dust has recently been shown to significantly affect the ability of mineral dust aerosol to act as cloud condensation nuclei. We have studied water adsorption as a function of relative humidity (RH) on goethite (α-FeO(OH)), a common component of atmospheric mineral dust. The goethite surface area and particle size was determined using BET analysis and with N2 as an adsorbate and scanning electron microscopy, respectively. Water adsorption on the sample was monitored using horizontal attenuated total reflectance Fourier transform infrared (HATR-FTIR) spectroscopy equipped with a flow cell. Water content was determined using Beer's law and the optical constants for bulk water. The results were analyzed using Type II adsorption isotherms to model multilayer adsorption, including BET (Brunauer, Emmet and Teller), FHH (Frenkel, Halsey and Hill) and Freundlich. BET fits to experimental data provide parameters of monolayer coverage, while the FHH and Freundlich isotherms provide insights into multilayer adsorption mechanisms. Results indicate that goethite contains 5% H2O by mass at 50% RH, which increases to 12% by mass at 90% RH. Adsorption parameters and experimental results will be presented.

  1. Volatile organic compound adsorption in a gas-solid fluidized bed.

    Science.gov (United States)

    Ng, Y L; Yan, R; Tsen, L T S; Yong, L C; Liu, M; Liang, D T

    2004-01-01

    Fluidization finds many process applications in the areas of catalytic reactions, drying, coating, combustion, gasification and microbial culturing. This work aims to compare the dynamic adsorption characteristics and adsorption rates in a bubbling fluidized bed and a fixed bed at the same gas flow-rate, gas residence time and bed height. Adsorption with 520 ppm methanol and 489 ppm isobutane by the ZSM-5 zeolite of different particle size in the two beds enabled the differentiation of the adsorption characteristics and rates due to bed type, intraparticle mass transfer and adsorbate-adsorbent interaction. Adsorption of isobutane by the more commonly used activated carbon provided the comparison of adsorption between the two adsorbent types. With the same gas residence time of 0.79 seconds in both the bubbling bed and fixed bed of the same bed size of 40 mm diameter and 48 mm height, the experimental results showed a higher rate of adsorption in the bubbling bed as compared to the fixed bed. Intraparticle mass transfer and adsorbent-adsorbate interaction played significant roles in affecting the rate of adsorption, with intraparticle mass transfer being more dominant. The bubbling bed was observed to have a steeper decline in adsorption rate with respect to increasing outlet concentration compared to the fixed bed. The adsorption capacities of zeolite for the adsorbates studied were comparatively similar in both beds; fluidizing, and using smaller particles in the bubbling bed did not increase the adsorption capacity of the ZSM-5 zeolite. The adsorption capacity of activated carbon for isobutane was much higher than the ZSM-5 zeolite for isobutane, although at a lower adsorption rate. Fourier transform infra-red (FTIR) spectroscopy was used as an analytical tool for the quantification of gas concentration. Calibration was done using a series of standards prepared by in situ dilution with nitrogen gas, based on the ideal gas law and relating partial pressure to gas

  2. Reactivity and Catalytic Activity of Hydrogen Atom Chemisorbed Silver Clusters.

    Science.gov (United States)

    Manzoor, Dar; Pal, Sourav

    2015-06-18

    Metal clusters of silver have attracted recent interest of researchers as a result of their potential in different catalytic applications and low cost. However, due to the completely filled d orbital and very high first ionization potential of the silver atom, the silver-based catalysts interact very weakly with the reacting molecules. In the current work, density functional theory calculations were carried out to investigate the effect of hydrogen atom chemisorption on the reactivity and catalytic properties of inert silver clusters. Our results affirm that the hydrogen atom chemisorption leads to enhancement in the binding energy of the adsorbed O2 molecule on the inert silver clusters. The increase in the binding energy is also characterized by the decrease in the Ag-O and increase in the O-O bond lengths in the case of the AgnH silver clusters. Pertinent to the increase in the O-O bond length, a significant red shift in the O-O stretching frequency is also noted in the case of the AgnH silver clusters. Moreover, the hydrogen atom chemisorbed silver clusters show low reaction barriers and high heat of formation of the final products for the environmentally important CO oxidation reaction as compared to the parent catalytically inactive clusters. The obtained results were compared with those of the corresponding gold and hydrogen atom chemisorbed gold clusters obtained at the same level of theory. It is expected the current computational study will provide key insights for future advances in the design of efficient nanosilver-based catalysts through the adsorption of a small atom or a ligand.

  3. Adsorption behaviors of thiophene, benzene, and cyclohexene on FAU zeolites: Comparison of CeY obtained by liquid-, and solid-state ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Yucai [College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266555, Shandong (China); Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Province, Liaoning Shihua University, Fushun 113001, Liaoning (China); Mo, Zhousheng; Yu, Wenguang; Dong, Shiwei; Duan, Linhai [College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266555, Shandong (China); Gao, Xionghou, E-mail: gaoxionghou@petrochina.com.cn [Petrochemical Research Institute, PetroChina Company Limited, 9 Dongzhimen North Street, Dongcheng District, Beijing 100007 (China); Song, Lijuan, E-mail: lsong56@263.net [College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266555, Shandong (China); Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Province, Liaoning Shihua University, Fushun 113001, Liaoning (China)

    2014-02-15

    Cerium containing Y zeolites were prepared by liquid- (L-CeY) and solid- (S-CeY) state ion exchange from NaY and HY, respectively. The structural and textural properties were characterized by XRD and N{sub 2} adsorption, and acidity properties were characterized by NH{sub 3} temperature-programmed desorption (NH{sub 3}-TPD) and in situ FTIR spectrum of chemisorbed pyridine (in situ Py-FTIR). Furthermore, the single component adsorption and multi-component competitive adsorption behavior of thiophene, benzene and cyclohexene on those zeolites have also been studied by using vapor adsorption isotherms, solution adsorption breakthrough curves, thermogravimetry and derivative thermogravimetry (TG/DTG), frequency response (FR) and in situ FTIR techniques. The results indicate that the primary adsorption mode of benzene is simply micropore filling process, but the nature of effect of aromatics on selective adsorption of thiophene is competitive adsorption. The strong chemical adsorptions and protonization reactions of thiophene and cyclohexene occur upon the Brönsted acid sites of the HY and L-CeY zeolites, and the preferable acid catalytic protonization reactions of olefins hinder the further adsorption of sulfur compounds.

  4. Prediction of Pure Component Adsorption Equilibria Using an Adsorption Isotherm Equation Based on Vacancy Solution Theory

    DEFF Research Database (Denmark)

    Marcussen, Lis; Aasberg-Petersen, K.; Krøll, Annette Elisabeth

    2000-01-01

    An adsorption isotherm equation for nonideal pure component adsorption based on vacancy solution theory and the Non-Random-Two-Liquid (NRTL) equation is found to be useful for predicting pure component adsorption equilibria at a variety of conditions. The isotherm equation is evaluated successfully...... adsorption systems, spreading pressure and isosteric heat of adsorption are also calculated....

  5. Ultra Low Concentration Adsorption Equilibria

    National Research Council Canada - National Science Library

    Mahle, John J; Buettner, Leonard C; LeVan, M. D; Schindler, Bryan J

    2006-01-01

    .... Specifically this work focuses on novel experimental and modeling methods to characterize and predict at ultra-low chemical vapor concentrations the protection afforded by adsorption-based vapor filtration systems...

  6. Potential Theory of Multicomponent Adsorption

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1998-01-01

    We developed a theory of multicomponent adsorption on the basis of the potential concept originally suggested by Polanyi. The mixture is considered as a heterogeneous substance segregated in the external field emitted by the adsorbent. The same standard equation of state, with no additional fitting...... parameters, is used for the segregated and for the bulk phases. With this approach, few parameters are needed to correlate pure component adsorption isotherms. These parameters may be used to predict adsorption equilibria of multicomponent mixtures without additional adjustment. A connection between...... the potential theory and the spreading pressure concept is established, and problems of the theory consistency are studied. Numerical algorithms are suggested for evaluation of the segregated state of the mixture in the potential field of adsorption forces. Comparison with experimental data shows good agreement...

  7. Adsorption kinetics of surfactants on activated carbon

    Science.gov (United States)

    Arnelli; Aditama, WP; Fikriani, Z.; Astuti, Y.

    2018-04-01

    A study on the adsorption of both cationic and anionic surfactants using activated carbon as well as the investigation of the adsorption isotherms and adsorption kinetics has been conducted. The results showed that the adsorption of sodium lauryl sulfate (SLS) by activated carbon was Langmuir’s adsorption isotherm while its adsorption kinetics showed pseudo-second order with an adsorption rate constant of 2.23 x 103 g mg-1 hour-1. Meanwhile, the adsorption of HDTMA-Br by activated carbon showed that the isotherm adsorption tended to follow Freundlich’s isotherm and was pseudo-second order with an adsorption rate constant of 89.39 g mg-1 hour-1.

  8. Adsorption of amylase enzyme on ultrafiltration membranes

    DEFF Research Database (Denmark)

    Beier, Søren; Enevoldsen, Ann Dorrit; Kontogeorgis, Georgios

    2007-01-01

    A method to measure the static adsorption on membrane surfaces has been developed and described. The static adsorption of an amylase-F has been measured on two different ultrafiltration membranes, both with a cut-off value of 10 kDa (a PES membrane and the ETNA10PP membrane, which is a surface......-modified PVDF membrane). The adsorption follows the Langmuir adsorption theory. Thus, the static adsorption consists of monolayer coverage. The static adsorption is expressed both as a permeability drop and an adsorption resistance. From the adsorption isotherms the maximum static permeability drops...... and the maximum static adsorption resistances are determined. The maximum static permeability drop for the hydrophobic PES membrane is 75 % and the maximum static adsorption resistance is 0.014 m2hbar/L. The maximum static permeability drop for the hydrophilic surface-modified PVDF membrane (ETNA10PP) is 23...

  9. Adsorption of antibiotics on microplastics.

    Science.gov (United States)

    Li, Jia; Zhang, Kaina; Zhang, Hua

    2018-06-01

    Microplastics and antibiotics are two classes of emerging contaminants with proposed negative impacts to aqueous ecosystems. Adsorption of antibiotics on microplastics may result in their long-range transport and may cause compound combination effects. In this study, we investigated the adsorption of 5 antibiotics [sulfadiazine (SDZ), amoxicillin (AMX), tetracycline (TC), ciprofloxacin (CIP), and trimethoprim (TMP)] on 5 types of microplastics [polyethylene (PE), polystyrene (PS), polypropylene (PP), polyamide (PA), and polyvinyl chloride (PVC)] in the freshwater and seawater systems. Scanning Electron Microscope (SEM) and X-ray diffractometer (XRD) analysis revealed that microplastics have different surface characterizes and various degrees of crystalline. Adsorption isotherms demonstrated that PA had the strongest adsorption capacity for antibiotics with distribution coefficient (K d ) values ranged from 7.36 ± 0.257 to 756 ± 48.0 L kg -1 in the freshwater system, which can be attributed to its porous structure and hydrogen bonding. Relatively low adsorption capacity was observed on other four microplastics. The adsorption amounts of 5 antibiotics on PS, PE, PP, and PVC decreased in the order of CIP > AMX > TMP > SDZ > TC with K f correlated positively with octanol-water partition coefficients (Log K ow ). Comparing to freshwater system, adsorption capacity in seawater decreased significantly and no adsorption was observed for CIP and AMX. Our results indicated that commonly observed polyamide particles can serve as a carrier of antibiotics in the aquatic environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Catalytic Ozonation by Iron Coated Pumice for the Degradation of Natural Organic Matters

    Directory of Open Access Journals (Sweden)

    Alper Alver

    2018-05-01

    Full Text Available The use of iron-coated pumice (ICP in heterogeneous catalytic ozonation significantly enhanced the removal efficiency of natural organic matters (NOMs in water, due to the synergistic effect of hybrid processes when compared to sole ozonation and adsorption. Multiple characterization analyses (BET, TEM, XRD, DLS, FT-IR, and pHPZC were employed for a systematic investigation of the catalyst surface properties. This analysis indicated that the ICP crystal structure was α-FeOOH, the surface hydroxyl group of ICP was significantly increased after coating, the particle size of ICP was about 200–250 nm, the BET surface area of ICP was about 10.56 m2 g−1, the pHPZC value of ICP was about 7.13, and that enhancement by iron loading was observed in the FT-IR spectra. The contribution of surface adsorption, hydroxyl radicals, and sole ozonation to catalytic ozonation was determined as 21.29%, 66.22%, and 12.49%, respectively. The reaction kinetic analysis with tert-Butyl alcohol (TBA was used as a radical scavenger, confirming that surface ferrous iron loading promoted the role of the hydroxyl radicals. The phosphate was used as an inorganic probe, and significantly inhibited the removal efficiency of catalytic NOM ozonation. This is an indication that the reactions which occur are more dominant in the solution phase.

  11. Synergetic mechanism of methanol–steam reforming reaction in a catalytic reactor with electric discharges

    International Nuclear Information System (INIS)

    Kim, Taegyu; Jo, Sungkwon; Song, Young-Hoon; Lee, Dae Hoon

    2014-01-01

    Highlights: • Methanol–steam reforming was performed on Cu catalysts under an electric discharge. • Discharge had a synergetic effect on the catalytic reaction for methanol conversion. • Discharge lowered the temperature for catalyst activation or light off. • Discharge controlled the yield and selectivity of species in a reforming process. • Adsorption triggered by a discharge was a possible mechanism for a synergetic effect. - Abstract: Methanol–steam reforming was performed on Cu/ZnO/Al 2 O 3 catalysts under an electric discharge. The discharge occurred between the electrodes where the catalysts were packed. The electric discharge was characterized by the discharge voltage and electric power to generate the discharge. The existence of a discharge had a synergetic effect on the catalytic reaction for methanol conversion. The electric discharge provided modified reaction paths resulting in a lower temperature for catalyst activation or light off. The discharge partially controlled the yield and selectivity of species in a reforming process. The aspect of control was examined in view of the reaction kinetics. The possible mechanisms for the synergetic effect between the catalytic reaction and electric discharge on methanol–steam reforming were addressed. A discrete reaction path, particularly adsorption triggered by an electric discharge, was suggested to be the most likely mechanism for the synergetic effect. These results are expected to provide a guide for understanding the plasma–catalyst hybrid reaction

  12. THz Wave Propagation on Strip Lines: Devices, Properties, and Applications

    Directory of Open Access Journals (Sweden)

    Y. Kadoya

    2008-06-01

    Full Text Available We report the propagation characteristics of THz pulses on micro-strip-lines and coplanar strip-lines, in which low permittivity polymer materials are used as the dielectric layer or the substrate. As a result of the low attenuation and small dispersion in the devices, the spectral width up to 3 THz can be achieved even after the 1 mm propagation. Spectroscopic characterizations of liquid or powder specimens are demonstrated using the devices. We also show a possibility of realizing a very low attenuation using a quadrupole mode in three strip coplanar lines on the polymer substrate.

  13. Improved dielectric functions in metallic films obtained via template stripping

    Science.gov (United States)

    Hyuk Park, Jong; Nagpal, Prashant; Oh, Sang-Hyun; Norris, David J.

    2012-02-01

    We compare the dielectric functions of silver interfaces obtained via thermal evaporation with those obtained with template stripping. Ellipsometry measurements show that the smoother template-stripped surfaces exhibit effective dielectric functions with a more negative real component and a smaller imaginary component, implying higher conductivity and less energy loss, respectively. These results agree with the relation between dielectric function and surface roughness derived from combining the effective-medium model and the Drude-Lorentz model. The improvement in the effective dielectric properties shows that metallic films prepared via template stripping can be favorable for applications in electronics, nanophotonics, and plasmonics.

  14. New technology for the production of magnesium strips and sheets

    Directory of Open Access Journals (Sweden)

    R. Kawalla

    2008-07-01

    Full Text Available A new production technology for magnesium strip, based on twin-roll-casting and strip rolling was developed in Freiberg Germany. By means of this economic method it is possible to produce strips in deep drawing quality with good forming properties in order to satisfy the request for low cost Mg sheets in the automotive and electronic industry. Both, coils as single sheets, were manufactured and rolled to a thickness of 1mm(0,5 mm. The technology of the new process and the properties of the twin-roll-casted material and the final sheets are presented.

  15. Substrate-mediated enhanced activity of Ru nanoparticles in catalytic hydrogenation of benzene

    KAUST Repository

    Liu, Xin

    2012-01-01

    The impact of carbon substrate-Ru nanoparticle interactions on benzene and hydrogen adsorption that is directly related to the performance in catalytic hydrogenation of benzene has been investigated by first-principles based calculations. The stability of Ru 13 nanoparticles is enhanced by the defective graphene substrate due to the hybridization between the dsp states of the Ru 13 particle with the sp 2 dangling bonds at the defect sites. The local curvature formed at the interface will also raise the Ru atomic diffusion barrier, and prohibit the particle sintering. The strong interfacial interaction results in the shift of averaged d-band center of the deposited Ru nanoparticle, from -1.41 eV for a freestanding Ru 13 particle, to -1.17 eV for the Ru/Graphene composites, and to -1.54 eV on mesocellular foam carbon. Accordingly, the adsorption energies of benzene are increased from -2.53 eV for the Ru/mesocellular foam carbon composites, to -2.62 eV on freestanding Ru 13 particles, to -2.74 eV on Ru/graphene composites. A similar change in hydrogen adsorption is also observed, and all these can be correlated to the shift of the d-band center of the nanoparticle. Thus, Ru nanoparticles graphene composites are expected to exhibit both high stability and superior catalytic performance in hydrogenation of arenes. © 2012 The Royal Society of Chemistry.

  16. CATALYTIC PERFORMANCES OF Fe2O3/TS-1 CATALYST IN PHENOL HYDROXYLATION REACTION

    Directory of Open Access Journals (Sweden)

    Didik Prasetyoko

    2010-07-01

    Full Text Available Hydroxylation reaction of phenol into diphenol, such as hydroquinone and catechol, has a great role in many industrial applications. Phenol hydroxylation reaction can be carried out using Titanium Silicalite-1 (TS-1 as catalyst and H2O2 as an oxidant. TS-1 catalyst shows high activity and selectivity for phenol hydroxylation reaction. However, its hydrophobic sites lead to slow H2O2 adsorption toward the active site of TS-1. Consequently, the reaction rate of phenol hydroxylation reaction is tends to be low. Addition of metal oxide Fe2O3 enhanced hydrophilicity of TS-1 catalyst. Liquid phase catalytic phenol hydroxylation using hydrogen peroxide as oxidant was carried out over iron (III oxide-modified TS-1 catalyst (Fe2O3/TS-1, that were prepared by impregnation method using iron (III nitrate as precursor and characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption, pyridine adsorption, and hydrophilicity techniques. Catalysts 1Fe2O3/TS-1 showed maximum catalytic activity of hydroquinone product. In this research, the increase of hydroquinone formation rate is due to the higher hydrophilicity of Fe2O3/TS-1 catalysts compare to the parent catalyst, TS-1.   Keywords: Fe2O3/TS-1, hydrophilic site, phenol hydroxylation

  17. Adsorption refrigeration technology theory and application

    CERN Document Server

    Wang, Ruzhu; Wu, Jingyi

    2014-01-01

    Gives readers a detailed understanding of adsorption refrigeration technology, with a focus on practical applications and environmental concerns Systematically covering the technology of adsorption refrigeration, this book provides readers with a technical understanding of the topic as well as detailed information on the state-of-the-art from leading researchers in the field. Introducing readers to background on the development of adsorption refrigeration, the authors also cover the development of adsorbents, various thermodynamic theories, the design of adsorption systems and adsorption refri

  18. Co and Fe-catalysts supported on sepiolite: effects of preparation conditions on their catalytic behaviors in high temperature gas flow treatment of dye.

    Science.gov (United States)

    Lin, Xiangfeng; Fang, Jian; Chen, Menglin; Huang, Zhi; Su, Chengyuan

    2016-08-01

    An efficient adsorbent/catalyst Co and Fe-catalysts loaded on sepiolite (Co-Fe/sepiolite) was successfully prepared for high temperature gas flow catalytic reaction by a simple impregnation method. The impact of preparation conditions (such as pH value of impregnation solution, impregnation time, calcination temperature, and time) on catalytic activity was studied. We found that the catalytic activity of Co-Fe/sepiolite was strongly influenced by all the investigated parameters. The regeneration efficiency (RE) was used to evaluate the catalytic activity. The RE is more noticeable at pH 5.0 of impregnation solution, impregnation time 18 h, calcination temperature 650 °C, and calcination time 3 h. This Co-Fe/sepiolite has great adsorption capacity in absorbing dye. It is used for an adsorbent to adsorb dye from wastewater solution under dynamic adsorption and saturated with dye, then regenerated with high temperature gas flow for adsorption/oxidation cycles. The Co-Fe/sepiolite acts as a catalyst to degrade the dye during regeneration under high temperature gas flow. Hence, the Co-Fe/sepiolite is not only an adsorbent but also a catalyst. The Co-Fe/sepiolite is more stable than sepiolite when applied in the treatment of plant's wastewater. The Co-Fe/sepiolite can be reused in adsorption-regeneration cycle. The results indicate the usability of the proposed combined process, dye adsorption on Co-Fe/sepiolite followed by the catalytic oxidation in high temperature gas flow.

  19. Fast timing readout for silicon strip detectors

    International Nuclear Information System (INIS)

    Jhingan, A.; Saneesh, N.; Kumar, M.

    2016-01-01

    The development and performance of a 16 channel hybrid fast timing amplifier (FTA), for extracting timing information from silicon strip detectors (SSD), is described. The FTA will be used in a time of flight (TOF) measurement, in which one SSD is used to obtain the ion velocity (A) as well as the energy information of a scattered particle. The TOF information with a thin transmission SSD, acting as ΔE detector (Z) in a detector telescope, will provide a unique detection system for the identification of reaction products in the slowed down beam campaign of low energy branch (LEB) at NUSTAR-FAIR. Such a system will also provide large solid angle coverage with ~ 100% detection efficiency, and adequate segmentation for angular information. A good timing resolution (≤ 100 ps) enables to have shorter flight paths, thus a closely packed 4π array should be feasible. Preamplifiers for energy readout in SSD are easily available. A major constraint with SSDs is the missing high density multichannel preamplifiers which can provide both fast timing as well as energy. Provision of both timing and energy processing, generally makes circuit bulky, with higher power consumption, which may not be suitable in SSD arrays. In case of DSSSD, the problem was overcome by using timing from one side and energy from the other side. A custom designed 16 channel FTA has been developed for DSSSD design W from Micron Semiconductors, UK

  20. Process Simulation Analysis of HF Stripping

    Directory of Open Access Journals (Sweden)

    Thaer A. Abdulla

    2015-02-01

    Full Text Available    HYSYS process simulator is used for the analysis of existing HF stripping column in LAB plant (Arab Detergent Company, Baiji-Iraq. Simulated column performance and profiles curves are constructed. The variables considered are the thermodynamic model option, bottom temperature, feed temperature, and column profiles for the temperature, vapor flow rate, liquid flow rate and composition. The five thermodynamic models options used (Margules, UNIQUAC, van laar, Antoine, and Zudkevitch-Joffee, affecting the results within (0.1-58% variation for the most cases.        The simulated results show that about 4% of paraffin (C10 & C11 presents at the top stream, which may cause a problem in the LAB production plant. The major variations were noticed for the total top vapor flow rate with bottom temperature and with feed composition. The column profiles maintain fairly constants from tray 5 to tray 18. The study gives evidence about a successful simulation with HYSYS because the results correspond with the real plant operation data.

  1. Profile of a science comic strip author

    CERN Multimedia

    Anaïs Schaeffer

    2014-01-01

    After studying visual arts, Lison Bernet worked as a lock keeper, waitress, grape picker, farm labourer and chef before finally returning to her first love: drawing. Today a scientific illustrator, Lison is the author of the cartoon strip "La BD du LHC", which she draws every month for LHC France (by CNRS/IN2P3 and CEA/Irfu, see here).   © Lison Bernet. Lison’s career path might seem somewhat chaotic, but it is a reflection of the artist herself: original and passionate. “I never do anything by half measures. When I got into cooking for example [Lison took a chef training course for adults], I became completely wrapped up in it. I even went as far as cooking roasts during my lunch hour, just for practice…” says Lison. On completing the course, Lison got a job as a chef on a canal boat. And it was then that she got the drawing bug again. “I started keeping an illustrated travel diary,” she says. &ldquo...

  2. The GLAST silicon-strip tracking system

    International Nuclear Information System (INIS)

    Johnson, Robert P.

    2000-01-01

    The GLAST instrument concept is a gamma-ray pair conversion telescope that uses silicon microstrip detector technology to track the electron-positron pairs resulting from gamma-ray conversions in thin lead foils. A cesium iodide calorimeter following the tracker is used to measure the gamma-ray energy. Silicon strip technology is mature and robust, with an excellent heritage in space science and particle physics. It has many characteristics important for optimal performance of a pair conversion telescope, including high efficiency in thin detector planes, low noise, and excellent resolution and two-track separation. The large size of GLAST and high channel count in the tracker puts demands on the readout technology to operate at very low power, yet with sufficiently low noise occupancy to allow self triggering. A prototype system employing custom-designed ASIC's has been built and tested that meets the design goal of approximately 200 W per channel power consumption with a noise occupancy of less than one hit per trigger per 10,000 channels. Detailed design of the full-scale tracker is well advanced, with non-flight prototypes built for all components, and a complete 50,000 channel engineering demonstration tower module is currently under construction and will be tested in particle beams in late 1999. The flight-instrument conceptual design is for a 4x4 array of tower modules with an aperture of 2.9 m2 and an effective area of greater than 8000 cm2

  3. The GLAST Silicon-Strip Tracking System

    International Nuclear Information System (INIS)

    Johnson, R

    2004-01-01

    The GLAST instrument concept is a gamma-ray pair conversion telescope that uses silicon microstrip detector technology to track the electron-positron pairs resulting from gamma ray conversions in thin lead foils. A cesium iodide calorimeter following the tracker is used to measure the gamma-ray energy. Silicon strip technology is mature and robust, with an excellent heritage in space science and particle physics. It has many characteristics important for optimal performance of a pair conversion telescope, including high efficiency in thin detector planes, low noise, and excellent resolution and two-track separation. The large size of GLAST and high channel count in the tracker puts demands on the readout technology to operate at very low power, yet with sufficiently low noise occupancy to allow self triggering. A prototype system employing custom-designed ASIC's has been built and tested that meets the design goal of approximately 200 (micro)W per channel power consumption with a noise occupancy of less than one hit per trigger per 10,000 channels. Detailed design of the full-scale tracker is well advanced, with non-flight prototypes built for all components, and a complete 50,000 channel engineering demonstration tower module is currently under construction and will be tested in particle beams in late 1999. The flight-instrument conceptual design is for a 4 x 4 array of tower modules with an aperture of 2.9 m 2 and an effective area of greater than 8000 cm 2

  4. Kinetics of heterogeneous catalytic reactions

    CERN Document Server

    Boudart, Michel

    2014-01-01

    This book is a critical account of the principles of the kinetics of heterogeneous catalytic reactions in the light of recent developments in surface science and catalysis science. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase acc

  5. Catalytic Organometallic Reactions of Ammonia

    Science.gov (United States)

    Klinkenberg, Jessica L.

    2012-01-01

    Until recently, ammonia had rarely succumbed to catalytic transformations with homogeneous catalysts, and the development of such reactions that are selective for the formation of single products under mild conditions has encountered numerous challenges. However, recently developed catalysts have allowed several classes of reactions to create products with nitrogen-containing functional groups from ammonia. These reactions include hydroaminomethylation, reductive amination, alkylation, allylic substitution, hydroamination, and cross-coupling. This Minireview describes examples of these processes and the factors that control catalyst activity and selectivity. PMID:20857466

  6. Catalytic cracking of hydrocarbon oils

    Energy Technology Data Exchange (ETDEWEB)

    1940-09-12

    A process is described for the vapor phase catalytic cracking of hydrocarbon oils boiling substantially in the gas oil range. The reaction takes place in the presence of a solid catalyst between 700 to 900/sup 0/F under pressure between atmospheric and 400 psi. A gas containing between 20 and 90 mol % of free hydrogen is used. The reaction is allowed to proceed until consumption of the free begins. The reaction is discontinued at that point and the catalyst is regenerated for further use.

  7. Molecular catalytic coal liquid conversion

    Energy Technology Data Exchange (ETDEWEB)

    Stock, L.M.; Yang, Shiyong [Univ. of Chicago, IL (United States)

    1995-12-31

    This research, which is relevant to the development of new catalytic systems for the improvement of the quality of coal liquids by the addition of dihydrogen, is divided into two tasks. Task 1 centers on the activation of dihydrogen by molecular basic reagents such as hydroxide ion to convert it into a reactive adduct (OH{center_dot}H{sub 2}){sup {minus}} that can reduce organic molecules. Such species should be robust withstanding severe conditions and chemical poisons. Task 2 is focused on an entirely different approach that exploits molecular catalysts, derived from organometallic compounds that are capable of reducing monocyclic aromatic compounds under very mild conditions. Accomplishments and conclusions are discussed.

  8. Regenerating an Arsenic Removal Iron-Based Adsorptive ...

    Science.gov (United States)

    The replacement of exhausted, adsorptive media used to remove arsenic from drinking water accounts for approximately 80% of the total operational and maintenance (O/M) costs of this commonly used small system technology. The results of three, full scale system studies of an on-site media regeneration process (Part 1) showed it to be effective in stripping arsenic and other contaminants from the exhausted media. Part 2, of this two part paper, presents information on the performance of the regenerated media to remove arsenic through multiple regeneration cycles (3) and the approximate cost savings of regeneration over media replacement. The results of the studies indicate that regenerated media is very effective in removing arsenic and the regeneration cost is substantially less than the media replacement cost. On site regeneration, therefore, provides small systems with alternative to media replacement when removing arsenic from drinking water using adsorptive media technology. Part 2 of a two part paper on the performance of the regenerated media to remove arsenic through multiple regeneration cycles (3) and the approximate cost savings of regeneration over media replacement.

  9. Continuous Strip Reduction Test Simulating Tribological Conditions in Ironing

    DEFF Research Database (Denmark)

    Üstünyagiz, Esmeray; Nielsen, Chris Valentin; Christiansen, Peter

    2017-01-01

    materials, surface roughnesses, normal pressure, sliding length, sliding speed, interface temperature and lubrication. This paper proposes a new Strip Reduction Test (SRT) for industrial ironing processes that is capable of replicating the highly severe tribological conditions that are experienced during...

  10. Hollow Mill for Extraction of Stripped Titanium Screws: An Easy ...

    African Journals Online (AJOL)

    countries. The known alternative in such condition is ... Key words: Hollow mill, stripped screws, titanium locked plates ... used a locally manufactured stainless steel hollow mill, ... head ‑ plate hole” assembly as a mono‑block single unit. In.

  11. The New Silicon Strip Detectors for the CMS Tracker Upgrade

    CERN Document Server

    Dragicevic, Marko

    2010-01-01

    The first introductory part of the thesis describes the concept of the CMS experiment. The tasks of the various detector systems and their technical implementations in CMS are explained. To facilitate the understanding of the basic principles of silicon strip sensors, the subsequent chapter discusses the fundamentals in semiconductor technology, with particular emphasis on silicon. The necessary process steps to manufacture strip sensors in a so-called planar process are described in detail. Furthermore, the effects of irradiation on silicon strip sensors are discussed. To conclude the introductory part of the thesis, the design of the silicon strip sensors of the CMS Tracker are described in detail. The choice of the substrate material and the complex geometry of the sensors are reviewed and the quality assurance procedures for the production of the sensors are presented. Furthermore the design of the detector modules are described. The main part of this thesis starts with a discussion on the demands on the ...

  12. Data acquisition software for the CMS strip tracker

    International Nuclear Information System (INIS)

    Bainbridge, R; Cripps, N; Fulcher, J; Radicci, V; Wingham, M; Baulieu, G; Bel, S; Delaere, C; Drouhin, F; Gill, K; Mirabito, L; Cole, J; Jesus, A C A; Giassi, A; Giordano, D; Gross, L; Hahn, K; Mersi, S; Nikolic, M; Tkaczyk, S

    2008-01-01

    The CMS silicon strip tracker, providing a sensitive area of approximately 200 m 2 and comprising 10 million readout channels, has recently been completed at the tracker integration facility at CERN. The strip tracker community is currently working to develop and integrate the online and offline software frameworks, known as XDAQ and CMSSW respectively, for the purposes of data acquisition and detector commissioning and monitoring. Recent developments have seen the integration of many new services and tools within the online data acquisition system, such as event building, online distributed analysis, an online monitoring framework, and data storage management. We review the various software components that comprise the strip tracker data acquisition system, the software architectures used for stand-alone and global data-taking modes. Our experiences in commissioning and operating one of the largest ever silicon micro-strip tracking systems are also reviewed

  13. Electroplating and stripping copper on molybdenum and niobium

    Science.gov (United States)

    Power, J. L.

    1978-01-01

    Molybdenum and niobium are often electroplated and subsequently stripped of copper. Since general standard plating techniques produce poor quality coatings, general procedures have been optimized and specified to give good results.

  14. Digital simulation of anodic stripping voltammetry from thin film electrodes

    International Nuclear Information System (INIS)

    Magallanes, J.F.

    1984-01-01

    The anodic stripping voltammetry (ASV) is routinely applied to control of Cu(II) in heavy water in the primary cooling loop of the Nuclear Power Reactor. The anodic stripping voltammetry (ASV) is a very well-known technique in electroanalytical chemistry. However, due to the complexity of the phenomena, it is practised with the fundamentals of empiric considerations. A geometric model for the anodic stripping voltammetry (ASV) from thin film electrodes which can be calculated by explicit digital simulation method is proposed as a possibility of solving the electrochemically reversible, cuasi-reversible and irreversible reactions under linear potential scan and multiple potential scans. (Until now the analytical mathematical method was applied to reversible reactions). All the results are compared with analytical solutions and experimental results and it permits to conclude that the anodic stripping voltammetry (ASV) can be studied with the simplicity and potentialities of explicit digital simulation methods. (M.E.L.) [es

  15. Results of Laboratory Testing of Advanced Power Strips: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Earle, L.; Sparn, B.

    2012-08-01

    This paper describes the results of a laboratory investigation to evaluate the technical performance of advanced power strip (APS) devices when subjected to a range of home entertainment center and home office usage scenarios.

  16. Nanoscale Test Strips for Multiplexed Blood Analysis, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of our nanoscale test strips, or nanostrips, is to provide rapid, low-cost, powerful multiplexed analyses in a diminutive form so that whole body health...

  17. Catalytic enantioselective Reformatsky reaction with ketones

    NARCIS (Netherlands)

    Fernandez-Ibanez, M. Angeles; Macia, Beatriz; Minnaard, Adriaan J.; Feringa, Ben L.

    2008-01-01

    Chiral tertiary alcohols were obtained with good yields and enantioselectivities via a catalytic Reformatsky reaction with ketones, including the challenging diaryl ketones, using chiral BINOL derivatives.

  18. High Pressure Water Stripping Using Multi-Orifice Nozzles

    Science.gov (United States)

    Hoppe, David

    1999-01-01

    The use of multi-orifice rotary nozzles greatly increases the speed and stripping effectiveness of high pressure water blasting systems, but also greatly increases the complexity of selecting and optimizing the operating parameters. The rotational speed of the nozzle must be coupled with its transverse velocity as it passes across the surface of the substrate being stripped. The radial and angular positions of each orifice must be included in the analysis of the nozzle configuration. Orifices at the outer edge of the nozzle head move at a faster rate than the orifices located near the center. The energy transmitted to the surface from the impact force of the water stream from an outer orifice is therefore spread over a larger area than energy from an inner orifice. Utilizing a larger diameter orifice in the outer radial positions increases the total energy transmitted from the outer orifice to compensate for the wider distribution of energy. The total flow rate from the combination of all orifices must be monitored and should be kept below the pump capacity while choosing orifice to insert in each position. The energy distribution from the orifice pattern is further complicated since the rotary path of all the orifices in the nozzle head pass through the center section. All orifices contribute to the stripping in the center of the path while only the outer most orifice contributes to the stripping at the edge of the nozzle. Additional orifices contribute to the stripping from the outer edge toward the center section. With all these parameters to configure and each parameter change affecting the others, a computer model was developed to track and coordinate these parameters. The computer simulation graphically indicates the cumulative affect from each parameter selected. The result from the proper choices in parameters is a well designed, highly efficient stripping system. A poorly chosen set of parameters will cause the nozzle to strip aggressively in some areas

  19. Fe-Mn bi-metallic oxides loaded on granular activated carbon to enhance dye removal by catalytic ozonation.

    Science.gov (United States)

    Tang, Shoufeng; Yuan, Deling; Zhang, Qi; Liu, Yameng; Zhang, Qi; Liu, Zhengquan; Huang, Haiming

    2016-09-01

    A Fe-Mn bi-metallic oxide supported on granular activated carbon (Fe-Mn GAC) has been fabricated by an impregnation-desiccation method and tested in the catalytic ozonation of methyl orange (MO) degradation and mineralization. X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy characterizations revealed that Fe-Mn oxides were successfully loaded and uniformly distributed on the GAC, and nitrogen adsorption isotherms showed that the supported GAC retained a large surface area and a high pore volume compared with the pristine GAC. The catalytic activity was systematically assessed by monitoring the MO removal efficiencies at different operational parameters, such as catalyst dosage, initial solution pH, and ozone flow rate. The Fe-Mn GAC exhibited better catalytic activity relative to ozone alone and GAC alone, improving the TOC removal by 24.5 and 11.5 % and COD removal by 13.6 and 7.3 %, respectively. The reusability of the hybrid was examined over five consecutive cyclic treatments. The Fe-Mn GAC catalytic activity was only a slight loss in the cycles, showing good stability. The addition of Na2CO3 as hydroxyl radicals (•OH) scavengers proved that the catalytic ozonation mechanism was the enhanced generation of •OH by the Fe-Mn GAC. The above results render the Fe-Mn GAC an industrially promising candidate for catalytic ozonation of dye contaminant removal.

  20. PECULIAR FEATURES PERTAINING TO STRIP FORMATION FROM BAR

    Directory of Open Access Journals (Sweden)

    G. N. Zdor

    2010-01-01

    Full Text Available The paper describes results of calculations and presents experimental substantiation of the dependence of a strip width being rolled out of a 10-mm diameter bar on its final thickness. It has been shown that the formation technology of thin steel strips out of a round bar makes it possible without any difficulties to obtain rolled products with the given cross-section dimensions due to proper selection of single drafting.

  1. The Strip: Las Vegas and the Symbolic Destruction of Spectacle

    OpenAIRE

    Al, Stefan Johannes

    2010-01-01

    Over the past 70 years, various actors have dramatically reconfigured the Las Vegas Strip in many forms. I claim that behind the Strip's "reinventions" lies a process of symbolic destruction. Since resorts distinguish themselves symbolically, each new round of capital accumulation relies on the destruction of symbolic capital of existing resorts. A new resort either ups the language within a paradigm, or causes a paradigm shift, which devalues the previous resorts even further. This is why, i...

  2. An analysis of stripping to isolated analog resonances

    International Nuclear Information System (INIS)

    Pessoa, E.F.; Toledo Piza, A.F.R. de.

    1983-04-01

    The Feshbach projection formalism is used to calculate the form factors for the (d,n) stripping process to isolated analog resonances. These are used in a standard DWBA stripping calculation in which the radial integration over all space is accomplished by including outerspace contributions evaluated along the complex contours of Vincent and Fortune. It turns out that the shape and magnitude of the predicted cross section is quite insensitive to the continuum proton wave emanating from the resonant residual state. (Author) [pt

  3. Petrochemical promoters in catalytic cracking

    International Nuclear Information System (INIS)

    Gomez, Maria; Vargas, Clemencia; Lizcano, Javier

    2010-01-01

    This study is based on the current scheme followed by a refinery with available Catalytic Cracking capacity to process new feedstocks such as Straight Run Naphtha and Naphthas from FCC. These feedstocks are of petrochemical interest to produce Ethane, Ethylene, Propylene, i-Butane, Toluene and Xylene. To evaluate the potential of these new streams versus the Cracking-charged Residues, it was performed a detailed chemical analysis on the structural groups in carbons [C1-C12] at the reactor product obtained in pilot plant. A catalyst with and without Propylene Promoter Additive was used. This study analyzes the differences in the chemical composition of the feedstocks, relating them to the yield of each petrochemical product. Straight Run Naphthas with a high content of Naphthenes, and Paraffines n[C5-C12] and i[C7-C12] are selective to the production of i-Butane and Propane, while Naphthas from FCC with a high content of n[C5-C12]Olefins, i-Olefins, and Aromatics are more selective to Propylene, Toluene, and Xylene. Concerning Catalytic Cracking of Naphthas, the Additive has similar selectivity for all the petrochemical products, their yields increase by about one point with 4%wt of Additive, while in cracking of Residues, the Additive increases in three points Propylene yield, corresponding to a selectivity of 50% (?C3= / ?LPG).

  4. Catalytic conversion of light alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J.E.

    1992-06-30

    The second Quarterly Report of 1992 on the Catalytic Conversion of Light Alkanes reviews the work done between April 1, 1992 and June 31, 1992 on the Cooperative Agreement. The mission of this work is to devise a new catalyst which can be used in a simple economic process to convert the light alkanes in natural gas to oxygenate products that can either be used as clean-burning, high octane liquid fuels, as fuel components or as precursors to liquid hydrocarbon uwspomdon fuel. During the past quarter we have continued to design, prepare, characterize and test novel catalysts for the mild selective reaction of light hydrocarbons with air or oxygen to produce alcohols directly. These catalysts are designed to form active metal oxo (MO) species and to be uniquely active for the homolytic cleavage of the carbon-hydrogen bonds in light alkanes producing intermediates which can form alcohols. We continue to investigate three molecular environments for the active catalytic species that we are trying to generate: electron-deficient macrocycles (PHASE I), polyoxometallates (PHASE II), and regular oxidic lattices including zeolites and related structures as well as other molecular surface structures having metal oxo groups (PHASE I).

  5. Catalytic converters in the fireplace

    International Nuclear Information System (INIS)

    Kouki, J.

    1995-01-01

    In addition to selecting the appropriate means of heating and using dry fuel, the amount of harmful emissions contained by flue gases produced by fireplaces can be reduced by technical means. One such option is to use an oxidising catalytic converter. Tests at TTS Institute's Heating Studies Experimental Station have focused on two such converters (dense and coarse) mounted in light-weight iron heating stoves. The ability of the dense catalytic converter to oxidise carbon monoxide gases proved to be good. The concentration of carbon monoxide in the flue gases was reduced by as much as 90 %. Measurements conducted by VTT (Technical Research Centre of Finland) showed that the conversion of other gases, e.g. of methane, was good. The exhaust resistance caused by the dense converter was so great as to necessitate the mounting of a fluegas evacuation fan in the chimney for the purpose of creating sufficient draught. When relying on natural draught, the dense converter requires a chimney of at least 7 metres and a by-pass connection while the fire is being lit. In addition, the converter will have to be constructed to be less dense and this will mean that it's capability to oxidise non-combusted gases will be reduced. The coarse converter did not impair the draught but it's oxidising property was insufficient. With the tests over, the converter was not observed to have become blocked up by impurities

  6. A new strips tracker for the upgraded ATLAS ITk detector

    Science.gov (United States)

    David, C.

    2018-01-01

    The ATLAS detector has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the next-generation tracking detector proposed for the High Luminosity LHC (HL-LHC), the so-called ATLAS Phase-II Upgrade, the fluences and radiation levels will be higher by as much as a factor of ten. The new sub-detectors must thus be faster, of larger area, more segmented and more radiation hard while the amount of inactive material should be minimized and the power supply to the front-end systems should be increased. For those reasons, the current inner tracker of the ATLAS detector will be fully replaced by an all-silicon tracking system that consists of a pixel detector at small radius close to the beam line and a large area strip tracker surrounding it. This document gives an overview of the design of the strip inner tracker (Strip ITk) and summarises the intensive R&D activities performed over the last years by the numerous institutes within the Strips ITk collaboration. These studies are accompanied with a strong prototyping effort to contribute to the optimisation of the Strip ITk's structure and components. This effort culminated recently in the release of the ATLAS Strips ITk Technical Design Report (TDR).

  7. Induction heating in in-line strip production process

    International Nuclear Information System (INIS)

    Costa, P.; Santinelli, M.

    1995-05-01

    ISP (In-line Strip Production), a continuous process for steel strip production, has recently been set in an italian innovative plant, where ecological impact and power requirements are lighter than usual. This report describes the studies performed by ENEA (Italian Agency for New Technologies, Energy and the Environment), while a prototype reheating facility was arranged by Acciaieria ISP in Cremona (Italy). The authors, after a study of the prototype electromagnetic field, calculate the heating rate, with the thermal network method. Then they detect, with a 1-D-FEM, the heat diffusion through the strip cross section. Afterward, since the heat distribution depends on the eddy current density one, which is given by the magnetic field distribution, the authors, with a 3-D-FEM, carry out a coupled, electromagnetic and thermal, analysis in time domain. The strip temperature map is established by the balance between skin depth heating and surface cooling: a thermal analysis, performed with a moving 2-D-FEM, take into account the effects of the different heating and cooling situations, originated by the strip moving at a speed of 6m/min through four consecutive reheating facilities. The temperatures of a strip sample heated by the prototype have been monitored, acquired by a computer and related with the simulation results. The little difference between experiment and simulation assessed the qualitative and quantitative validity of this analysis, that has come out to be a tool, useful to evaluate the effects of possible improvements to the ISP process

  8. The development of drift-strip detectors based on CdZnTe

    DEFF Research Database (Denmark)

    Gostilo, V.; Budtz-Jørgensen, Carl; Kuvvetli, Irfan

    2002-01-01

    The design and technological development of a CdZnTe drift strip detector is described. The device is based on a monocrystal of dimensions 10 x 10 x 3 mm(3) and has a pitch of 200 mum and a strip width of 100 mum. The strip length is 9.5 mm. The distribution of the leakage currents of the strips...

  9. Kinetics of nitrate adsorption and reduction by nano-scale zero valent iron (NZVI): Effect of ionic strength and initial pH

    DEFF Research Database (Denmark)

    Kim, Do-Gun; Hwang, Yuhoon; Shin, Hang-Sik

    2016-01-01

    Kinetic models for pollutants reduction by Nano-scale Zero Valent Iron (NZVI) were tested in this study to gain a better understanding and description of the reaction. Adsorption kinetic models and a heterogeneous catalytic reaction kinetic equation were proposed for nitrate removal and for ammon...

  10. Improving carbon tolerance of Ni-YSZ catalytic porous membrane by palladium addition for low temperature steam methane reforming

    Science.gov (United States)

    Lee, Sang Moon; Won, Jong Min; Kim, Geo Jong; Lee, Seung Hyun; Kim, Sung Su; Hong, Sung Chang

    2017-10-01

    Palladium was added on the Ni-YSZ catalytic porous membrane by wet impregnation and electroless plating methods. Its surface morphology characteristics and carbon deposition properties for the low temperature steam methane reforming were investigated. The addition of palladium could obviously be enhanced the catalytic activity as well as carbon tolerance of the Ni-YSZ porous membrane. The porous membranes were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR), CH4 temperature-programmed reduction (CH4-TPR), and O2 temperature-programmed oxidation (O2-TPO). It was found that the Pd-Ni-YSZ catalytic porous membrane showed the superior stability as well as the deposition of carbon on the surface during carbon dissociation adsorption at 650 °C was also suppressed.

  11. A biological oil adsorption filter

    Energy Technology Data Exchange (ETDEWEB)

    Pasila, A [University of Helsinki (Finland). Dept. of Agricultural Engineering and Household Technology

    2005-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  12. A biological oil adsorption filter

    International Nuclear Information System (INIS)

    Pasila, A.

    2005-01-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  13. The chemical and catalytic properties of nanocrystalline metal oxides prepared through modified sol-gel synthesis

    Science.gov (United States)

    Carnes, Corrie Leigh

    The goal of this research was to synthesize, characterize and study the chemical properties of nanocrystalline metal oxides. Nanocrystalline (NC) ZnO, CuO, NiO, Al2O3, and the binary Al2O 3/MgO and ZnO/CuO were prepared through modified sol gel methods. These NC metal oxides were studied in comparison to the commercial (CM) metal oxides. The samples were characterized by XRD, TGA, FTIR, BET, and TEM. The NC samples were all accompanied by a significant increase in surface area and decrease in crystallite size. Several chemical reactions were studied to compare the NC samples to the CM samples. One of the reactions involved a high temperature reaction between carbon tetrachloride and the oxide to form carbon dioxide and the corresponding metal chloride. A similar high temperature reaction was conducted between the metal oxide and hydrogen sulfide to form water and the corresponding metal sulfide. A room temperature gas phase adsorption was studied where SO2 was adsorbed onto the oxide. A liquid phase adsorption conducted at room temperature was the destructive adsorption of paraoxon (a toxic insecticide). In all reactions the NC samples exhibited greater activity, destroying or adsorbing a larger amount of the toxins compared to the CM samples. To better study surface area effects catalytic reactions were also studied. The catalysis of methanol was studied over the nanocrystalline ZnO, CuO, NiO, and ZnO/CuO samples in comparison to their commercial counterparts. In most cases the NC samples proved to be more active catalysts, having higher percent conversions and turnover numbers. A second catalytic reaction was also studied, this reaction was investigated to look at the support effects. The catalysis of cyclopropane to propane was studied over Pt and Co catalysts. These catalysts were supported onto NC and CM alumina by impregnation. By observing differences in the catalytic behavior, support effects have become apparent.

  14. Catalytic conversion of 11C-labeled methanol over Cs-ZSM-5 zeolite

    International Nuclear Information System (INIS)

    Sarkadi-Priboczki, E.; Kovacs, Z.; Kumar, N.; Salmi, T.; Murzin, D.Yu.

    2004-01-01

    Reaction mechanism of the conversion of 11 C labeled methanol over basic Cs-ZSM-5 zeolite catalyst was investigated and the reaction products obtained were compared with that of H-ZSM-5 acidic catalyst. The catalytic experiments were carried out by passing 11 C-labeled methanol with He as a carrier gas over Cs-ZSM-5 packed in a micro reactor. After adsorption of the radio methanol, the catalyst was heated up to 330 deg C. The products of the catalytic conversion of the 11 C-labeled methanol were analyzed by radio-gas chromatography (gas chromatograph with thermal conductivity detector on-line coupled with a radioactivity detector). (N.T.)

  15. A consistent reaction scheme for the selective catalytic reduction of nitrogen oxides with ammonia

    DEFF Research Database (Denmark)

    Janssens, Ton V.W.; Falsig, Hanne; Lundegaard, Lars Fahl

    2015-01-01

    For the first time, the standard and fast selective catalytic reduction of NO by NH3 are described in a complete catalytic cycle, that is able to produce the correct stoichiometry, while only allowing adsorption and desorption of stable molecules. The standard SCR reaction is a coupling of the ac...... for standard SCR. Finally, the role of a nitrate/nitrite equilibrium and the possible in uence of Cu dimers and Brønsted sites are discussed, and an explanation is offered as to how a catalyst can be effective for SCR, while being a poor catalyst for NO oxidation to NO2....... spectroscopy (FTIR). A consequence of the reaction scheme is that all intermediates in fast SCR are also part of the standard SCR cycle. The calculated activation energy by density functional theory (DFT) indicates that the oxidation of an NO molecule by O2 to a bidentate nitrate ligand is rate determining...

  16. Synthesis and catalytic performance of ZSM-5/MCM-41 composite molecular sieve from palygorskite

    Science.gov (United States)

    Jiang, Jinlong; Wu, Mei; Yang, Yong; Duanmu, Chuansong; Chen, Jing; Gu, Xu

    2017-10-01

    ZSM-5/MCM-41 composite molecular sieve has been hydrothermally synthesized through a two-step crystallization process using palygorskite (PAL) as silicon and aluminum source. The products were characterized by various means and their catalytic properties for acetalization of cyclohexanone and esterification of acetic acid and n-butanol were also investigated. In the first step ZSM-5 zeolite could be formed from the acid-treated PAL after hydrothermal treatment using tetrapropylammonium bromide as template. XRD patterns, N2 adsorption and desorption data, and TEM images show that the composite obtained in the secondary step had a well-ordered mesoporous MCM-41 phase and a microporous ZSM-5 zeolite phase. Compared with ZSM-5, ZSM-5/MCM-41 composite possessed more total acid amount, weak acid sites and large pore structure due to the formation of MCM-41 and exhibited higher catalytic activity for the acetalization and esterification reaction.

  17. Efficient catalytic system for the direct transformation of lignocellulosic biomass to furfural and 5-hydroxymethylfurfural.

    Science.gov (United States)

    Zhang, Luxin; Xi, Guoyun; Zhang, Jiaxin; Yu, Hongbing; Wang, Xiaochang

    2017-01-01

    A feasible approach was developed for the co-production of 5-hydroxymethylfurfural (5-HMF) and furfural from corncob via a new porous polytriphenylamine-SO 3 H (SPTPA) solid acid catalyst in lactone solvents. XRD, SEM, XPS, N 2 adsorption-desorption, elemental analysis, TG-DTA, acid-base titration and FTIR spectroscopy techniques were used to characterize the catalyst. This study demonstrates and optimizes the catalytic performance of SPTPA and solvent selection. SPTPA was found to exhibit superior catalytic ability in γ-valerolactone (GVL). Under the optimum reaction conditions, simultaneously encouraging yields of furfural (73.9%) and 5-HMF (32.3%) were achieved at 448K. The main advantages of this process include reasonable yields of both 5-HMF and furfural in the same reaction system, practical simplicity for the raw biomass utilization, and the use of a safe and environmentally benign solvent. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Effect of preparation conditions on physicochemical, surface and catalytic properties of cobalt ferrite prepared by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    El-Shobaky, G.A., E-mail: elshobaky@yahoo.co [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt); Turky, A.M.; Mostafa, N.Y.; Mohamed, S.K. [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

    2010-03-18

    Cobalt ferrite nanoparticles were prepared via thermal treatment of cobalt-iron mixed hydroxides at 400-600 {sup o}C. The mixed hydroxides were coprecipitated from their nitrates solutions using NaOH as precipitating agent. The effects of pH and temperature of coprecipitation and calcination temperature on the physicochemical, surface and catalytic properties of the prepared ferrites were studied. The prepared systems were characterized using TG, DTG, DTA, chemical analysis, atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) as well as surface and texture properties based on nitrogen adsorption-desorption isotherms. The prepared cobalt ferrites were found to be mesoporous materials that have crystallite size ranges between 8 and 45 nm. The surface and catalytic properties of the produced ferrite phase were strongly dependent on coprecipitation conditions of the mixed hydroxides and on their calcination temperature.

  19. Electro-catalytic oxidation of ethanol on platinum-iridium mixtures supported on glassy carbon

    International Nuclear Information System (INIS)

    Rodriguez, Henry; Hoyos Bibian

    2004-01-01

    Electro-catalytic oxidation of ethanol on platinum-iridium mixtures supported on glassy carbon was studied, in acid media at different temperatures and concentrations. During the maturation time of deposited iridium, the surface is covered by an irreversible oxide formation, which affects the behavior of the catalytic mixture. The Pt 7 0 Ir 3 0 and Pt 9 0 Ir 1 0 mixtures seem to be a little more active than the Pt/C electrode at potentials below 800 mV (vs. HRE). In all electrodes appears two reactions: partial ethanol oxidation to produce acetaldehyde (main path of reaction at low temperatures and high electrode coverage with ethanol adsorption residues) and the total oxidation to carbon dioxide which is considerable at potential above 800 mV and it is increased with increasing temperature

  20. Adsorptive differential pulse voltammetry for determination of uranium in sea water

    International Nuclear Information System (INIS)

    Khandekar, R.N.; Raghunath, R.

    1990-01-01

    An adsorptive stripping voltammetric procedure for direct determination of trace quantities of uranium in sea water is described. Optimal conditions include pH 6.7, 2 x 10 -5 M 8-hydroxyquinoline (oxine) and collection potential of -0.4V (vs Ag/AgCl) at hanging mercury drop electrode. With controlled adsorptive accumulation for one min. a detection limit of 2.8 x 10 -10 M uranium is obtained. The response is linear upto 7 x 10 -8 M uranium and the relative standard deviation at 4 x 10 -9 M uranium is 11.5%. The effect of possible interference from other metals has been investigated. The accuracy of the method has been tested by comparison with the results obtained by fluorimetric method. (author). 2 figs., 1 tab., 20 refs

  1. Determination of uranium in sea water by adsorptive differential pulse voltametry

    International Nuclear Information System (INIS)

    Khandekar, R.N.; Raghunath, Radha

    1991-01-01

    An adsorptive stripping voltametric procedure for direct determination of trace quantities of uranium in sea water has been described. Optimal conditions include pH 6.7, 2 x 10 -5 M 8-hydroxy quinoline (oxine) and collection potential of -0.4V (Vs Ag/AgCl) at hanging mercury drop electrode. With controlled adsorptive accumulation for one minute a detection limit of 2.8 x 10 -10 M uranium is obtained. The response is linear upto 7 x 10 -8 M uranium and the relative standard deviation at 4 x 10 -9 M is 11.5%. The effect of possible interference from other metals has been investigated. (author). 14 refs., 1 tab

  2. Catalytic combustion of methane over mixed oxides derived from Co-Mg/Al ternary hydrotalcites

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zheng [Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, OX1 3QR (United Kingdom); Research Centre of Eco-Environmental Sciences, CAS, Beijing 100085 (China); Jesus College, University of Oxford, OX1 3DW (United Kingdom); Yu, Junjie; Cheng, Jie; Hao, Zhengping [Research Centre of Eco-Environmental Sciences, CAS, Beijing 100085 (China); Xiao, Tiancun; Edwards, Peter P. [Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, OX1 3QR (United Kingdom); Jones, Martin O. [Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, OX1 3QR (United Kingdom); Rutherford Appleton Laboratory, Didcot, OX11 0QX (United Kingdom)

    2010-01-15

    Co{sub x}Mg{sub 3-x} /Al composite oxides (xCoMAO-800) were prepared by calcination of Co{sub x}Mg{sub 3-x}/Al hydrotalcites (x=0.0,0.5,1.0,1.5,2.0,2.5,3.0, respectively) at 800 C. The materials were characterized using XRD, TG-DSC, N{sub 2} adsorption-desorption and TPR. The methane catalytic combustion over the xCoMAO-800 was assessed in a fixed bed micro-reactor. The results revealed that cobalt can be homogenously dispersed into the matrices of the hydrotalcites and determines the structure, specific surface areas and porosity of the derived xCoMAO-800 oxide catalysts. The thermal stability and homogeneity of the hydrotalcites markedly depends on the cobalt concentration in the hydrotalcites. The Co-based hydrotalcite-derived oxides exhibit good activity in the catalytic combustion of methane. The catalytic activity over the xCoMAO-800 oxides enhances with increasing x up to 1.5, but subsequently decreases dramatically as cobalt loadings are further increased. The 1.5CoMAO-800 catalyst shows the best methane combustion activity, igniting methane at 450 C and completing methane combustion around 600 C. The catalytic combustion activity over the xCoMAO-800 oxides are closely related to the strong Co-Mg/Al interaction within the mixed oxides according to the TG-DSC, TPR and activity characteristics. (author)

  3. Natural clinoptilolite exchanged with iron: characterization and catalytic activity in nitrogen monoxide reduction

    Directory of Open Access Journals (Sweden)

    Daria Tito-Ferro

    2016-12-01

    Full Text Available The aim of this work was to characterize the natural clinoptilolite from Tasajeras deposit, Cuba, modified by hydrothermal ion-exchange with solutions of iron (II sulfate and iron (III nitrate in acid medium. Besides this, its catalytic activity to reduce nitrogen monoxide with carbon monoxide/propene in the presence of oxygen was evaluated. The characterization was performed by Mössbauer and UV-Vis diffuse reflectance spectroscopies and adsorption measurements. The obtained results lead to conclude that in exchanged samples, incorporated divalent and trivalent irons are found in octahedral coordination. Both irons should be mainly in cationic extra-framework positions inside clinoptilolite channels as charge compensating cations, and also as iron oxy-hydroxides resulting from limited hydrolysis of these cations. The iron (III exchanged samples has a larger amount of iron oxy-hydroxides agglomerates. The iron (II exchanged samples have additionally iron (II sulfate adsorbed. The catalytic activity in the nitrogen monoxide reduction is higher in the exchanged zeolites than starting. Among all samples, those exchanged of iron (II has the higher catalytic activity. This lead to outline that, main catalytically active centers are associated with divalent iron.

  4. High-efficiency plasma catalytic removal of dilute benzene from air

    International Nuclear Information System (INIS)

    Fan, Hong-Yu; Shi, Chuan; Li, Xiao-Song; Zhao, De-Zhi; Xu, Yong; Zhu, Ai-Min

    2009-01-01

    Achieving complete oxidation, good humidity tolerance and low energy cost is the key issue that needs to be addressed in plasma catalytic volatile organic compounds removal from air. For this purpose, Ag/HZSM-5 catalyst-packed dielectric barrier discharge using a cycled system composed of a storage stage and a discharge stage was studied. For dilute benzene removal from simulated air, Ag/HZSM-5 catalysts exhibit not only preferential adsorption of benzene in humid air at the storage stage but also almost complete oxidation of adsorbed benzene at the discharge stage. Five 'storage-discharge' cycles were examined, which suggests that Ag/HZSM-5 catalysts are very stable during the cycled 'storage-discharge' (CSD) plasma catalytic process. High oxidation rate of absorbed benzene as well as low energy cost can be achieved at a moderate discharge power. In an example of the CSD plasma catalytic remedy of simulated air containing 4.7 ppm benzene with 50% RH and 600 ml min -1 flow rate, the energy cost was as low as 3.7 x 10 -3 kWh m -3 air. This extremely low energy cost to remove low-concentration pollutants from air undoubtedly makes the environmental applications of the plasma catalytic technique practical.

  5. Nanostructured, mesoporous Au/TiO2 model catalysts – structure, stability and catalytic properties

    Directory of Open Access Journals (Sweden)

    Matthias Roos

    2011-09-01

    Full Text Available Aiming at model systems with close-to-realistic transport properties, we have prepared and studied planar Au/TiO2 thin-film model catalysts consisting of a thin mesoporous TiO2 film of 200–400 nm thickness with Au nanoparticles, with a mean particle size of ~2 nm diameter, homogeneously distributed therein. The systems were prepared by spin-coating of a mesoporous TiO2 film from solutions of ethanolic titanium tetraisopropoxide and Pluronic P123 on planar Si(100 substrates, calcination at 350 °C and subsequent Au loading by a deposition–precipitation procedure, followed by a final calcination step for catalyst activation. The structural and chemical properties of these model systems were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, N2 adsorption, inductively coupled plasma ionization spectroscopy (ICP–OES and X-ray photoelectron spectroscopy (XPS. The catalytic properties were evaluated through the oxidation of CO as a test reaction, and reactivities were measured directly above the film with a scanning mass spectrometer. We can demonstrate that the thin-film model catalysts closely resemble dispersed Au/TiO2 supported catalysts in their characteristic structural and catalytic properties, and hence can be considered as suitable for catalytic model studies. The linear increase of the catalytic activity with film thickness indicates that transport limitations inside the Au/TiO2 film catalyst are negligible, i.e., below the detection limit.

  6. Studies of Catalytic Properties of Inorganic Rock Matrices in Redox Reactions

    Directory of Open Access Journals (Sweden)

    Nikolay M. Dobrynkin

    2017-09-01

    Full Text Available Intrinsic catalytic properties of mineral matrices of various kinds (basalts, clays, sandstones were studied, which are of interest for in-situ heavy oil upgrading (i.e., underground to create advanced technologies for enhanced oil recovery. The elemental, surface and phase composition and matrix particle morphology, surface and acidic properties were studied using elemental analysis, X-ray diffraction, adsorption and desorption of nitrogen and ammonia. The data on the catalytic activity of inorganic matrices in ammonium nitrate decomposition (reaction with a large gassing, oxidation of hydrocarbons and carbon monoxide, and hydrocracking of asphaltenes into maltenes (the conversion of heavy hydrocarbons into more valuable light hydrocarbons were discussed. In order to check their applicability for the asphaltenes hydrocracking catalytic systems development, basalt and clay matrices were used as supports for iron/basalt, nickel/basalt and iron/clay catalysts. The catalytic activity of the matrices in the reactions of the decomposition of ammonium nitrate, oxidation of hydrocarbons and carbon monoxide, and hydrocracking of asphaltens was observed for the first time.

  7. Catalytic ozonation of fenofibric acid over alumina-supported manganese oxide

    Energy Technology Data Exchange (ETDEWEB)

    Rosal, Roberto, E-mail: roberto.rosal@uah.es [Departamento de Quimica Analitica e Ingenieria Quimica, Universidad de Alcala, E-28771 Alcala de Henares (Spain); Gonzalo, Maria S.; Rodriguez, Antonio; Garcia-Calvo, Eloy [Departamento de Quimica Analitica e Ingenieria Quimica, Universidad de Alcala, E-28771 Alcala de Henares (Spain)

    2010-11-15

    The catalytic ozonation of fenofibric acid was studied using activated alumina and alumina-supported manganese oxide in a semicontinuous reactor. The rate constants at 20 deg. C for the non-catalytic reaction of fenofibric acid with ozone and hydroxyl radicals were 3.43 {+-} 0.20 M{sup -1} s{sup -1} and (6.55 {+-} 0.33) x 10{sup 9} M{sup -1} s{sup -1}, respectively. The kinetic constant for the catalytic reaction between fenofibric acid and hydroxyl radicals did not differ significantly from that of homogeneous ozonation, either using Al{sub 2}O{sub 3} or MnO{sub x}/Al{sub 2}O{sub 3}. The results showed a considerable increase in the generation of hydroxyl radicals due to the use of catalysts even in the case of catalytic runs performed using a real wastewater matrix. Both catalysts promoted the decomposition of ozone in homogeneous phase, but the higher production of hydroxyl radicals corresponded to the catalyst with more activity in terms of ozone decomposition. We did not find evidence of the catalysts having any effect on rate constants, which suggests that the reaction may not involve the adsorption of organics on catalyst surface.

  8. Test-beam evaluation of heavily irradiated silicon strip modules for ATLAS Phase-II Strip Tracker Upgrade

    CERN Document Server

    Blue, Andrew; The ATLAS collaboration

    2018-01-01

    The planned HL-LHC (High Luminosity LHC) is being designed to maximise the physics potential of the LHC with 10 years of operation at instantaneous luminosities of 7.5x1034cm−2s−1. A consequence of this increased luminosity is the expected radiation damage requiring the tracking detectors to withstand hadron equivalences to over 1x1015 1 MeV neutron equivalent per cm2 in the ATLAS Strips system. The silicon strip tracker exploits the concept of modularity. Fast readout electronics, deploying 130nm CMOS front-end electronics are glued on top of a silicon sensor to make a module. The radiation hard n-in-p micro-strip sensors used have been developed by the ATLAS ITk Strip Sensor collaboration and produced by Hamamatsu Photonics. A series of tests were performed at the DESY-II and CERN SPS test beam facilities to investigate the detailed performance of a strip module with both 2.5cm and 5cm length strips before and after irradiation with 8x1014neqcm−2 protons and a total ionising dose of 37.2MRad. The DURA...

  9. Catalytic properties and acidity of modified MCM-41 mesoporous materials with low Si/Al ratio: heptane isomerisation

    Directory of Open Access Journals (Sweden)

    Ahmed Belhakem

    2006-06-01

    Full Text Available The catalytic properties and acidity of modified MCM-41 with a low Si/Al ratio and 0-95% NH4+ exchange were investigated. The samples were characterised by X-ray diffraction, scanning and transmission electron microscopy, and nitrogen adsorption. The acidity was studied by pyridine adsorption, temperature programmed desorption (TPD of ammonia, and infrared (IR spectroscopy. Adsorption of pyridine and IR spectroscopy indicated various types of Lewis and Brönsted acid sites. The density distribution of acid sites was determined by TPD. Both Lewis and Brönsted acid sites were found to be active in the heptane isomerisation. The presence of aluminium (low Si/Al combined to the ionic exchange between Na+ and NH4+ increases the acidity of MCM-41 materials. A close correlation between acidity and isomerisation was observed. Coke deposition, which reduces the activity, was also studied.

  10. Investigations on the heterogenous catalytic hydrogenation using isotope effect and gamma- and neutron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kudlacek, R; Cabicar, J [Ceske Vysoke Uceni Technicke, Prague (Czechoslovakia). Katedra Jaderne Chemie

    1976-01-01

    The kinetic and solvent isotope effects during the maleic acid heterogeneous catalytic hydrogenation and deuteration in light and heavy water have been studied. Also the effect of the gamma and neutron irradiation on the Ni-ZnO catalysts (with various ratios of components) on the reaction kinetics and mechanism has been measured, as well as the effect of pH on the adsorption behaviour of maleic acid and the temperature dependence of the reaction rate. Existence of different adsorption centers for hydrogen and maleic acid could be deduced from these experiments. A reaction mechanism based on the two-dimensional diffusion of components in the surface is proposed. The catalyst is formed from Ni and ZnO-microspheres. Hydrogen is bound to nickel and maleic acid is adsorbed on the ZnO-microspheres. The reaction takes place on the boundary layers of these microspheres.

  11. Removal of gas phase low-concentration toluene over Mn, Ag and Ce modified HZSM-5 catalysts by periodical operation of adsorption and non-thermal plasma regeneration.

    Science.gov (United States)

    Wang, Wenzheng; Wang, Honglei; Zhu, Tianle; Fan, Xing

    2015-07-15

    Ag/HZSM-5, Mn/HZSM-5, Ce/HZSM-5, Ag-Mn/HZSM-5 and Ce-Mn/HZSM-5 were prepared by impregnation method. Both their adsorption capacity and catalytic activity were investigated for the removal of gas phase low-concentration toluene by periodical operation of adsorption and non-thermal plasma regeneration. Results show that catalysts loaded with Ag (Ag/HZSM-5 and Ag-Mn/HZSM-5) had larger adsorption capacity for toluene than the other catalysts. And Ag-Mn/HZSM-5 displayed the best catalytic performance for both toluene oxidation by non-thermal plasma and byproducts suppression. On the other hand, the deactivated catalyst can be fully regenerated by calcining in air stream when its adsorption capacity and catalytic activity of the Ag-Mn/HZSM-5 catalyst was found to be decreased after 10 cycles of periodical adsorption and non-thermal regeneration. Copyright © 2015. Published by Elsevier B.V.

  12. Development of the photo catalytic materials for the purification and deodorization of hazardous wastes

    International Nuclear Information System (INIS)

    Hong, Gye Woon; Park, Ji Yeon; Jung, Choong Hwan; Kim, Weon Ju

    1999-12-01

    A hazardous material treatment system utilizing photochemical reaction is a new technology which does not produce any secondary pollutants after dissolving treatment because it is activated by solar photo energy. Photo catalysis reaction apparatus using photo catalytic reaction of TiO 2 was fabricated and installed to food waste treatment system for removing bad smell during treatment of food waste. Evolved gas was analysed by gas chromatograph and active carbon fiber sheet and yarn were used as adsorption media for photo catalysis in order to increase the effectiveness of filter system. (author)

  13. Using scaling relations to understand trends in the catalytic activity of transition metals

    International Nuclear Information System (INIS)

    Jones, G; Bligaard, T; Abild-Pedersen, F; Noerskov, J K

    2008-01-01

    A method is developed to estimate the potential energy diagram for a full catalytic reaction for a range of late transition metals on the basis of a calculation (or an experimental determination) for a single metal. The method, which employs scaling relations between adsorption energies, is illustrated by calculating the potential energy diagram for the methanation reaction and ammonia synthesis for 11 different metals on the basis of results calculated for Ru. It is also shown that considering the free energy diagram for the reactions, under typical industrial conditions, provides additional insight into reactivity trends

  14. Generalized hydrodynamic treatment of the interplay between restricted transport and catalytic reactions in nanoporous materials.

    Science.gov (United States)

    Ackerman, David M; Wang, Jing; Evans, James W

    2012-06-01

    Behavior of catalytic reactions in narrow pores is controlled by a delicate interplay between fluctuations in adsorption-desorption at pore openings, restricted diffusion, and reaction. This behavior is captured by a generalized hydrodynamic formulation of appropriate reaction-diffusion equations (RDE). These RDE incorporate an unconventional description of chemical diffusion in mixed-component quasi-single-file systems based on a refined picture of tracer diffusion for finite-length pores. The RDE elucidate the nonexponential decay of the steady-state reactant concentration into the pore and the non-mean-field scaling of the reactant penetration depth.

  15. Tailoring the electronic structure of graphene for catalytic and nanoelectronic applications

    DEFF Research Database (Denmark)

    Vallejo, Federico Calle; García Lastra, Juan Maria

    2011-01-01

    We explore possible routes to tailor the catalytic and electronic properties of graphitic materials through doping. The investigation is carried out by theoretical Density Functional Theory (DFT) and tight-binding calculations. We show that Feporphyrin- like sites inserted in graphitic sheets......, created after doping are active towards the Oxygen Reduction reaction (ORR). On the other hand, we also show that it is possible to tune the opening of a gap in the band structure of graphene by changing the adsorption periodicity of molecules on its surface....

  16. Heterogeneous catalytic degradation of polyacrylamide solution | Hu ...

    African Journals Online (AJOL)

    Modified with trace metal elements, the catalytic activity of Fe2O3/Al2O3 could be changed greatly. Among various trace metal elements, Fe2O3/Al2O3 catalysts modified with Co and Cu showed great increase on catalytic activity. International Journal of Engineering, Science and Technology, Vol. 2, No. 7, 2010, pp. 110- ...

  17. Adsorption studies on Pt(111)

    International Nuclear Information System (INIS)

    Hopster, H.

    1977-06-01

    The adsorption of O 2 , CO, and C 2 H 2 as well as the CO oxidation on Pt(111) were studied by high-resolution electron spectroscopy. Using a platinum monocrystal sample with a contonuous stage density, the adhesion coefficient for O 2 and the reaction probability for CO were determined as a function of stage density and oxygen cover by measuring the oxygen cover and its time behaviour. The study of vibrations of adsorbed CO showed that CO is bound in linear form on two different adsorption sites. The adsorption of acetylene was studied at 140 K and 300 K. The frequencies of the C-H stretching and flexural vibrations as well as the C-C-H bonding angle were determined. (orig./GSC) [de

  18. Catalytic hydrodeoxygenation of methyl-substituted phenols: correlations of kinetic parameters with molecular properties.

    Science.gov (United States)

    Massoth, F E; Politzer, P; Concha, M C; Murray, J S; Jakowski, J; Simons, Jack

    2006-07-27

    The hydrodeoxygenation of methyl-substituted phenols was carried out in a flow microreactor at 300 degrees C and 2.85 MPa hydrogen pressure over a sulfided CoMo/Al(2)O(3) catalyst. The primary reaction products were methyl-substituted benzene, cyclohexene, cyclohexane, and H(2)O. Analysis of the results suggests that two independent reaction paths are operative, one leading to aromatics and the other to partially or completely hydrogenated cyclohexanes. The reaction data were analyzed using Langmuir-Hinshelwood kinetics to extract the values of the reactant-to-catalyst adsorption constant and of the rate constants characterizing the two reaction paths. The adsorption constant was found to be the same for both reactions, suggesting that a single catalytic site center is operative in both reactions. Ab initio electronic structure calculations were used to evaluate the electrostatic potentials and valence orbital ionization potentials for all of the substituted phenol reactants. Correlations were observed between (a) the adsorption constant and the two reaction rate constants measured for various methyl-substitutions and (b) certain moments of the electrostatic potentials and certain orbitals' ionization potentials of the isolated phenol molecules. On the basis of these correlations to intrinsic reactant-molecule properties, a reaction mechanism is proposed for each pathway, and it is suggested that the dependencies of adsorption and reaction rates upon methyl-group substitution are a result of the substituents' effects on the electrostatic potential and orbitals rather than geometric (steric) effects.

  19. Method of fabricating a catalytic structure

    Science.gov (United States)

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

    2009-09-22

    A precursor to a catalytic structure comprising zinc oxide and copper oxide. The zinc oxide has a sheet-like morphology or a spherical morphology and the copper oxide comprises particles of copper oxide. The copper oxide is reduced to copper, producing the catalytic structure. The catalytic structure is fabricated by a hydrothermal process. A reaction mixture comprising a zinc salt, a copper salt, a hydroxyl ion source, and a structure-directing agent is formed. The reaction mixture is heated under confined volume conditions to produce the precursor. The copper oxide in the precursor is reduced to copper. A method of hydrogenating a carbon oxide using the catalytic structure is also disclosed, as is a system that includes the catalytic structure.

  20. A thermogravimetric analysis (TGA) method to determine the catalytic conversion of cellulose from carbon-supported hydrogenolysis process

    International Nuclear Information System (INIS)

    Leal, Glauco F.; Ramos, Luiz A.; Barrett, Dean H.; Curvelo, Antonio Aprígio S.; Rodella, Cristiane B.

    2015-01-01

    Graphical abstract: - Highlights: • A new method to determine the catalytic conversion of cellulose using TGA has been developed. • TGA is able to differentiate between carbon from cellulose and carbon from the catalyst. • Building an analytical curve from TGA results enables the accurate determination of cellulose conversion. - Abstract: The ability to determine the quantity of solid reactant that has been transformed after a catalytic reaction is fundamental in accurately defining the conversion of the catalyst. This quantity is also central when investigating the recyclability of a solid catalyst as well as process control in an industrial catalytic application. However, when using carbon-supported catalysts for the conversion of cellulose this value is difficult to obtain using only a gravimetric method. The difficulty lies in weighing errors caused by loss of the solid mixture (catalyst and non-converted cellulose) after the reaction and/or moisture adsorption by the substrate. These errors are then propagated into the conversion calculation giving erroneous results. Thus, a quantitative method using thermogravimetric analysis (TGA) has been developed to determine the quantity of cellulose after a catalytic reaction by using a tungsten carbide catalyst supported on activated carbon. Stepped separation of TGA curves was used for quantitative analysis where three thermal events were identified: moisture loss, cellulose decomposition and CO/CO 2 formation. An analytical curve was derived and applied to quantify the residual cellulose after catalytic reactions which were performed at various temperatures and reaction times. The catalytic conversion was calculated and compared to the standard gravimetric method. Results showed that catalytic cellulose conversion can be determined using TGA and exhibits lower uncertainty (±2%) when compared to gravimetric determination (±5%). Therefore, it is a simple and relatively inexpensive method to determine catalytic

  1. Catalytic hydrogenation of carbon monoxide

    International Nuclear Information System (INIS)

    Wayland, B.B.

    1993-12-01

    Focus of this project is on developing new approaches for hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. The strategies to accomplish CO reduction are based on favorable thermodynamics manifested by rhodium macrocycles for producing a series of intermediates implicated in the catalytic hydrogenation of CO. Metalloformyl complexes from reactions of H 2 and CO, and CO reductive coupling to form metallo α-diketone species provide alternate routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. Electronic and steric effects associated with the ligand arrays along with the influences of the reaction medium provide the chemical tools for tuning these factors. Non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics are promising candidates for future development

  2. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J; Koljonen, T [VTT Energy, Espoo (Finland)

    1997-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  3. Non-catalytic recuperative reformer

    Science.gov (United States)

    Khinkis, Mark J.; Kozlov, Aleksandr P.; Kurek, Harry

    2015-12-22

    A non-catalytic recuperative reformer has a flue gas flow path for conducting hot flue gas from a thermal process and a reforming mixture flow path for conducting a reforming mixture. At least a portion of the reforming mixture flow path is embedded in the flue gas flow path to permit heat transfer from the hot flue gas to the reforming mixture. The reforming mixture flow path contains substantially no material commonly used as a catalyst for reforming hydrocarbon fuel (e.g., nickel oxide, platinum group elements or rhenium), but instead the reforming mixture is reformed into a higher calorific fuel via reactions due to the heat transfer and residence time. In a preferred embodiment, extended surfaces of metal material such as stainless steel or metal alloy that are high in nickel content are included within at least a portion of the reforming mixture flow path.

  4. Studies of Catalytic Model Systems

    DEFF Research Database (Denmark)

    Holse, Christian

    The overall topic of this thesis is within the field of catalysis, were model systems of different complexity have been studied utilizing a multipurpose Ultra High Vacuum chamber (UHV). The thesis falls in two different parts. First a simple model system in the form of a ruthenium single crystal...... of the Cu/ZnO nanoparticles is highly relevant to industrial methanol synthesis for which the direct interaction of Cu and ZnO nanocrystals synergistically boost the catalytic activity. The dynamical behavior of the nanoparticles under reducing and oxidizing environments were studied by means of ex situ X......-ray Photoelectron Electron Spectroscopy (XPS) and in situ Transmission Electron Microscopy (TEM). The surface composition of the nanoparticles changes reversibly as the nanoparticles exposed to cycles of high-pressure oxidation and reduction (200 mbar). Furthermore, the presence of metallic Zn is observed by XPS...

  5. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  6. NH3 adsorption on anatase-TiO2(101)

    Science.gov (United States)

    Koust, Stig; Adamsen, Kræn C.; Kolsbjerg, Esben Leonhard; Li, Zheshen; Hammer, Bjørk; Wendt, Stefan; Lauritsen, Jeppe V.

    2018-03-01

    The adsorption of ammonia on anatase TiO2 is of fundamental importance for several catalytic applications of TiO2 and for probing acid-base interactions. Utilizing high-resolution scanning tunneling microscopy (STM), synchrotron X-ray photoelectron spectroscopy, temperature-programmed desorption (TPD), and density functional theory (DFT), we identify the adsorption mode and quantify the adsorption strength on the anatase TiO2(101) surface. It was found that ammonia adsorbs non-dissociatively as NH3 on regular five-fold coordinated titanium surface sites (5f-Ti) with an estimated exothermic adsorption energy of 1.2 eV for an isolated ammonia molecule. For higher adsorbate coverages, the adsorption energy progressively shifts to smaller values, due to repulsive intermolecular interactions. The repulsive adsorbate-adsorbate interactions are quantified using DFT and autocorrelation analysis of STM images, which both showed a repulsive energy of ˜50 meV for nearest neighbor sites and a lowering in binding energy for an ammonia molecule in a full monolayer of 0.28 eV, which is in agreement with TPD spectra.

  7. Catalytic degradation of the soil fumigant 1,3-dichloropropene in aqueous biochar slurry

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Jiaolong [School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Cheng, Yuxiao; Sun, Mingxing [Shanghai Entry–Exit Inspection and Quarantine Bureau, Shanghai 200135 (China); Yan, Lili [School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Shen, Guoqing, E-mail: gqsh@sjtu.edu.cn [School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

    2016-11-01

    Biochar has been explored as a cost-effective sorbent of contaminants, such as soil fumigant. However, contaminant-loaded biochar probably becomes a source of secondary air pollution. In this study, biochars developed from cow manure and rice husk at 300 °C or 700 °C were used to investigate the catalytic degradation of the soil fumigant 1,3-dichloropropene (1,3-D) in aqueous biochar slurry. Results showed that the adsorption of 1,3-D on the biochars was influenced by Langmuir surface monolayer adsorption. The maximum adsorption capacity of cow manure was greater than that of rice husk at the same pyrolysis temperature. Batch experiments revealed that 1,3-D degradation was improved in aqueous biochar slurry. The most rapid 1,3-D degradation occurred on cow manure-derived biochar produced at 300 °C (C-300), with t{sub 1/2} = 3.47 days. The degradation efficiency of 1,3-D on C-300 was 95.52%. Environmentally persistent free radicals (EPFRs) in biochars were detected via electron paramagnetic resonance (EPR) techniques. Dissolved organic matter (DOM) and hydroxyl radical (·OH) in biochars were detected by using a fluorescence spectrophotometer coupled with a terephthalic acid trapping method. The improvement of 1,3-D degradation efficiency may be attributed to EPFRs and DOM in aqueous biochar slurry. Our results may pose implications in the development of effective reduction strategies for soil fumigant emission with biochar. - Highlights: • Hydrolysis of 1,3-D was accelerated in aqueous biochar slurry. • 1,3-D adsorption kinetics on biochars fitted well with Langmuir model. • Cow manure biochar showed higher catalytic degradation activity for 1,3-D than rice husk biochar did. • EPFRs and DOM have potential roles in 1,3-D degradation on biochar.

  8. Catalytic Conversion of Biomass to Fuels and Chemicals Using Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei; Zheng, Richard; Brown, Heather; Li, Joanne; Holladay, John; Cooper, Alan; Rao, Tony

    2012-04-13

    This project provides critical innovations and fundamental understandings that enable development of an economically-viable process for catalytic conversion of biomass (sugar) to 5-hydroxymethylfurfural (HMF). A low-cost ionic liquid (Cyphos 106) is discovered for fast conversion of fructose into HMF under moderate reaction conditions without any catalyst. HMF yield from fructose is almost 100% on the carbon molar basis. Adsorbent materials and adsorption process are invented and demonstrated for separation of 99% pure HMF product and recovery of the ionic liquid from the reaction mixtures. The adsorbent material appears very stable in repeated adsorption/regeneration cycles. Novel membrane-coated adsorbent particles are made and demonstrated to achieve excellent adsorption separation performances at low pressure drops. This is very important for a practical adsorption process because ionic liquids are known of high viscosity. Nearly 100% conversion (or dissolution) of cellulose in the catalytic ionic liquid into small molecules was observed. It is promising to produce HMF, sugars and other fermentable species directly from cellulose feedstock. However, several gaps were identified and could not be resolved in this project. Reaction and separation tests at larger scales are needed to minimize impacts of incidental errors on the mass balance and to show 99.9% ionic liquid recovery. The cellulose reaction tests were troubled with poor reproducibility. Further studies on cellulose conversion in ionic liquids under better controlled conditions are necessary to delineate reaction products, dissolution kinetics, effects of mass and heat transfer in the reactor on conversion, and separation of final reaction mixtures.

  9. Catalytic degradation of the soil fumigant 1,3-dichloropropene in aqueous biochar slurry

    International Nuclear Information System (INIS)

    Qin, Jiaolong; Cheng, Yuxiao; Sun, Mingxing; Yan, Lili; Shen, Guoqing

    2016-01-01

    Biochar has been explored as a cost-effective sorbent of contaminants, such as soil fumigant. However, contaminant-loaded biochar probably becomes a source of secondary air pollution. In this study, biochars developed from cow manure and rice husk at 300 °C or 700 °C were used to investigate the catalytic degradation of the soil fumigant 1,3-dichloropropene (1,3-D) in aqueous biochar slurry. Results showed that the adsorption of 1,3-D on the biochars was influenced by Langmuir surface monolayer adsorption. The maximum adsorption capacity of cow manure was greater than that of rice husk at the same pyrolysis temperature. Batch experiments revealed that 1,3-D degradation was improved in aqueous biochar slurry. The most rapid 1,3-D degradation occurred on cow manure-derived biochar produced at 300 °C (C-300), with t 1/2 = 3.47 days. The degradation efficiency of 1,3-D on C-300 was 95.52%. Environmentally persistent free radicals (EPFRs) in biochars were detected via electron paramagnetic resonance (EPR) techniques. Dissolved organic matter (DOM) and hydroxyl radical (·OH) in biochars were detected by using a fluorescence spectrophotometer coupled with a terephthalic acid trapping method. The improvement of 1,3-D degradation efficiency may be attributed to EPFRs and DOM in aqueous biochar slurry. Our results may pose implications in the development of effective reduction strategies for soil fumigant emission with biochar. - Highlights: • Hydrolysis of 1,3-D was accelerated in aqueous biochar slurry. • 1,3-D adsorption kinetics on biochars fitted well with Langmuir model. • Cow manure biochar showed higher catalytic degradation activity for 1,3-D than rice husk biochar did. • EPFRs and DOM have potential roles in 1,3-D degradation on biochar.

  10. Theoretical insight of adsorption cooling

    KAUST Repository

    Chakraborty, Anutosh

    2011-06-03

    This letter proposes and presents a thermodynamic formulation to calculate the energetic performances of an adsorption cooler as a function of pore widths and volumes of solid adsorbents. The simulated results in terms of the coefficient of performance are validated with experimental data. It is found from the present analysis that the performance of an adsorption cooling device is influenced mainly by the physical characteristics of solid adsorbents, and the characteristics energy between the adsorbent-adsorbate systems. The present study confirms that there exists a special type of silicagel having optimal physical characteristics that allows us to obtain the best performance.

  11. Theoretical insight of adsorption cooling

    KAUST Repository

    Chakraborty, Anutosh; Leong, Kai Choong; Thu, Kyaw; Saha, Bidyut Baran; Ng, Kim Choon

    2011-01-01

    This letter proposes and presents a thermodynamic formulation to calculate the energetic performances of an adsorption cooler as a function of pore widths and volumes of solid adsorbents. The simulated results in terms of the coefficient of performance are validated with experimental data. It is found from the present analysis that the performance of an adsorption cooling device is influenced mainly by the physical characteristics of solid adsorbents, and the characteristics energy between the adsorbent-adsorbate systems. The present study confirms that there exists a special type of silicagel having optimal physical characteristics that allows us to obtain the best performance.

  12. Potential Theory of Multicomponent Adsorption

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1998-01-01

    We developed a theory of multicomponent adsorption on the basis of the potential concept originally suggested by Polanyi. The mixture is considered as a heterogeneous substance segregated in the external field emitted by the adsorbent. The same standard equation of state, with no additional fitting...... and high degree of predictability of the theory developed....... the potential theory and the spreading pressure concept is established, and problems of the theory consistency are studied. Numerical algorithms are suggested for evaluation of the segregated state of the mixture in the potential field of adsorption forces. Comparison with experimental data shows good agreement...

  13. The evolution of catalytic function

    Science.gov (United States)

    Maurel, Marie-Christine; Ricard, Jacques

    2006-03-01

    It is very likely that the main driving force of enzyme evolution is the requirement to improve catalytic and regulatory efficiency which results from the intrinsic performance as well as from the spatial and functional organization of enzymes in living cells. Kinetic co-operativity may occur in simple monomeric proteins if they display “slow” conformational transitions, at the cost of catalytic efficiency. Oligomeric enzymes on the other hand can be both efficient and co-operative. We speculate that the main reason for the emergence of co-operative oligomeric enzymes is the need for catalysts that are both cooperative and efficient. As it is not useful for an enzyme to respond to a change of substrate concentration in a complex kinetic way, the emergence of symmetry has its probable origin in a requirement for “functional simplicity”. In a living cell, enzyme are associated with other macromolecules and membranes. The fine tuning of their activity may also be reached through mutations of the microenvironment. Our hypothesis is that these mutations are related to the vectorial transport of molecules, to achieve the hysteresis loops of enzyme reactions generated by the coupling of reaction and diffusion, through the co-operativity brought about by electric interactions between a charged substrate and a membrane, and last but not least, through oscillations. As the physical origins of these effects are very simple and do not require complex molecular devices, it is very likely that the functional advantage generated by the spatial and functional organization of enzyme molecules within the cell have appeared in prebiotic catalysis or very early during the primeval stages of biological evolution. We shall began this paper by presenting the nature of the probable earliest catalysts in the RNA world.

  14. Catalytic hydrolysis of COS over CeO_2 (110) surface: A density functional theory study

    International Nuclear Information System (INIS)

    Song, Xin; Ning, Ping; Wang, Chi; Li, Kai; Tang, Lihong; Sun, Xin

    2017-01-01

    Graphical abstract: CeO_2 decreases the maximum energy barrier by 76.15 kcal/mol. H_2O plays a role as a bridge in the process of joint adsorption. Catalytic effect of CeO_2 in the hydrolysis of COS is mainly reflected on the C−O channel. - Highlights: • H_2O is easier adsorbed on the CeO_2 (110) surface than COS. • When COS and H_2O jointly adsorb on the CeO_2 (110) surface, the H_2O molecule plays a role as a bridge. • Ce−O−H bond can enhance the adsorption effect. • Catalytic effect of CeO_2 in the hydrolysis of COS is mainly reflected on the C−O channel. - Abstract: Density functional theory (DFT) calculations were performed to investigate the reaction pathways for catalytic hydrolysis of COS over CeO_2 (110) surface using Dmol"3 model. The thermodynamic stability analysis for the suggested routes of COS hydrolysis to CO_2 and H_2S was evaluated. The absolute values of adsorption energy of H_2O-CeO_2 are higher than that of COS-CeO_2. Meanwhile, the adsorption energy and geometries show that H_2O is easier adsorbed on the surface of CeO_2 (110) than COS. H_2O plays a role as a bridge in the process of joint adsorption. H_2O forms more Ce−O−H groups on the CeO_2 (110) surface. CeO_2 decreases the maximum energy barrier by 76.15 kcal/mol. The migration of H from H_2O to COS is the key for the hydrolysis reaction. C−O channel is easier to occur than C−S channel. Experimental result shows that adding of CeO_2 can increase COS removal rate and prolong the 100% COS removal rate from 180 min to 210 min. The difference between Fe_2O_3 and CeO_2 for the hydrolysis of COS is characterized in the atomic charge transfer and the formation of H−O bond and H−S bond. The transfer effect of H in H_2O to S in COS over CeO_2 decreases the energy barriers of hydrolysis reaction, and enhances the reaction activity of COS hydrolysis.

  15. Method of making steel strapping and strip

    Energy Technology Data Exchange (ETDEWEB)

    Robert D. Reilly

    2000-02-16

    The technical progress obtained for this time frame consisted of the awarding of two contracts for determination of metallurgical parameters for heat treatment of strapping and strip which are unavailable from current technology and/or published data in this field. The two contractors were Bricmont, Inc. and the Department of Materials Science and Engineering at the Technological Institute of Northwestern University, Evanston, IL. Phase 1 of the two stage contract with Bricmont, Inc. which provided a computer analysis of the cooling rates of a typical range of thickness' of strapping was completed. This study was developed for the purpose of determining the time parameters for quenching low carbon steels to a martensitic microstructure within the time frame of the design of the proposed process. It also provides design criteria for cooling to ambient for the total process. This data is required for Phase 2 of the Bricmont proposal which completes the design and specifications of the total heat treating and cooling system for the process. This becomes the basis for developing the cost and space requirements for this component of the production line. The authors do not intend to award Phase 2 until the work done at Northwestern University discussed hereafter is completed. On or about May 1, 1999 a contract for a project entitled ``Effects of Steel Composition and Quench Rate on Microstructure and Mechanical Properties of Strapping'' to be performed at the Department of Materials Science and Engineering was awarded. The delay in initiating this project was due to the legal interpretation and final agreement of the intellectual provisions of the award by the author's attorneys, Northwestern's attorneys and the legal representative in the Chicago office of the DOE. The work to date includes rapid quenching of a number of different steel compositions and microstructure on an existing drop quench test apparatus. It was initially assumed that this

  16. Fast gas adsorption measurements for complicated adsorption mechanisms

    NARCIS (Netherlands)

    Robens, E.; Poulis, J.A.; Massen, C.H.

    2000-01-01

    Jäntti introduced a method to reduce the time required for the stepwise measurement of adsorption isotherms. After each pressure change he measured the adsorbed mass three times and calculated its equilibrium value at the new pressure. In the present paper, we discuss the applicability of this

  17. CONTAMINANT ADSORPTION AND OXIDATION VIA FENTON REACTION

    Science.gov (United States)

    A ground water treatment process is proposed involving two cgemical processes: adsorption and oxidation. Adsorption of an organic compound onto granulated activated carbon (GAC) containing iron conveniently results in immobilizing and concentrating contaminants from the ground w...

  18. In-situ stripping of H{sub 2}S in gasoil hydrodesulphurization - reactor design considerations

    Energy Technology Data Exchange (ETDEWEB)

    Nava, J.A.O.; Krishna, R. [Amsterdam Univ., Dept. of Chemical Engineering, Amsterdam (Netherlands)

    2004-02-01

    In order to meet future diesel specifications the sulphur content of diesel would need to be reduced to below 50 ppm. This requirement would require improved reactor configurations. In this study we examine the benefits of counter-current contacting of gas oil with H{sub 2}, over conventional co-current contacting in a trickle bed hydrodesulphurization (HDS) reactor. In counter-current contacting, we achieve in-situ stripping of H{sub 2}S from the liquid phase; this is beneficial to the HDS kinetics. A comparison simulation study shows that counter-current contacting would require about 20% lower catalyst load than co-current contacting. However, counter-current contacting of gas and liquid phases in conventionally used HDS catalysts, of 1.5 mm sizes, is not possible due to flooding limitations. The catalysts need to be housed in special wire gauze envelopes as in the catalytic bales or KATAPAK-S configurations. A preliminary hardware design of a counter-current HDS reactor using catalytic bales was carried out in order to determine the technical feasibility. Using a realistic sulphur containing feedstock, the target of 50 ppm S content of desulphurized oil could be met in a reactor of reasonable dimensions. The study also underlines the need for accurate modelling of thermal effects during desulphurization. Our study also shows that interphase mass transfer is unlikely to be a limiting factor and there is a need to develop improved reactor configurations allowing for increased catalyst loading, at the expense of gas-liquid interfacial area. (Author)

  19. Investigating the effect of gas flow rate, inlet ozone concentration and relative humidity on the efficacy of catalytic ozonation process in the removal of xylene from waste airstream

    Directory of Open Access Journals (Sweden)

    H.R. MokaramI

    2010-10-01

    Full Text Available Background and aimsThe catalytic ozonation is an efficient process for the degradation of volatile organic compounds from contaminated air stream. This study was aimed at investigating the efficacy of catalytic ozonation process in removal of xylene from the polluted air stream andthe influence of retention time (gas flow rate, inlet ozone dose and relative humidity on this performanceMethodsthe catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selectedoperational variables.ResultsThe results indicated that the efficiency of catalytic ozonation was greater than that of single adsorption in removal of xylene under similar inlet concentration and relative humidity. We found a significant catalytic effect for activated carbon when used in combination with ozonation process, leading to improvement of xylene removal percentage. In addition, the elimination capacity of the system improved with the increase of inlet ozone dose as well as gas flow rate. The relative humidity showed a positive effect of the xylene removal at the range of 5 to 50%, while the higher humidity (more than 50% resulted in reduction of the performance.ConclusionThe findings of the present work revealed that the catalytic ozonation process can be an efficient technique for treating the air streams containing industrial concentrations of xylene. Furthermore, there is a practical potential to retrofit the present adsorption systems intothe catalytic ozonation simply by coupling them with the ozonation system. the catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selected

  20. Mesoporous templated silicas: stability, pore size engineering and catalytic activation

    International Nuclear Information System (INIS)

    Vansant, Etienne

    2003-01-01

    The Laboratory of Adsorption and Catalysis has focused its research activities on the synthesis and activation of new porous materials. In the past few years, we have succeeded in developing easy and reproducible pathways to synthesize a huge variety of mesoporous crystalline materials. Points of interest in the synthesis of Mesoporous Templated Silicas are (i) stabilization of the structure, to withstand hydrothermal, thermal and mechanical pressure, (ii) pore size engineering to systematically control the pore size, pore volume and the ratio micro/mesopores and (iii) ease and reproducibility of the synthesis procedure, applying green principles, such as template recuperation. By carefully adapting the synthesis conditions and composition of the synthesis gel, using surfactants (long chain quaternary ammonium ions) and co-templates (long chain amines, alcohols or alkanes), the pore size of the obtained materials can be controlled from 1.5 to 7.0 nm, retaining the very narrow pore size distribution. Alternatively, materials with combined micro- and mesoporosity can be synthesized, using neutral surfactants (triblock copolymers). Hereby, the optimization of the SBA-15 and SBA-16 synthesis is being done in order to create mesoporous materials with microporous walls. The second research line is the controlled activation of MTS materials, by grafting or incorporation of catalytic active centers. We have developed for this purpose the Molecular Designed Dispersion method, which uses metal diketonate complexes as precursors. It is shown that in all cases the dispersion of the metal oxides on the surface is much better compared to the conventional grafting techniques. We have studied and published activation with V, Ti, Mo, Fe, Al and Cr species on different MTS materials. The structure and location of the active metal ion is the subject of an extensive spectroscopic investigation, using FT-IR, FT-Raman, UV-Vis DR coupled with selective chemisorption experiments and

  1. ADSORPTION MALACHITE GREEN ON NATURAL ZEOLITE

    OpenAIRE

    Eko Ariyanto

    2012-01-01

    A natural zeolite was employed as adsorbent for reducing of malachite green from aqueous solution. A batch system was applied to study the adsorption of malachite green in single system on natural zeolite. The adsorption studies indicate that malachite green in single component system follows the second-order kinetics and the adsorption is diffusion process with two stages for malachite green. Malachite green adsorption isotherm follows the Langmuir model.

  2. ADSORPTION MALACHITE GREEN ON NATURAL ZEOLITE

    Directory of Open Access Journals (Sweden)

    Eko Ariyanto

    2012-02-01

    Full Text Available A natural zeolite was employed as adsorbent for reducing of malachite green from aqueous solution. A batch system was applied to study the adsorption of malachite green in single system on natural zeolite. The adsorption studies indicate that malachite green in single component system follows the second-order kinetics and the adsorption is diffusion process with two stages for malachite green. Malachite green adsorption isotherm follows the Langmuir model.

  3. Validation of the catalytic properties of Cu-Os/13X using single fixed bed reactor in selective catalytic reduction of NO

    International Nuclear Information System (INIS)

    Oh, Kwang Seok; Woo, Seong Ihl

    2007-01-01

    Catalytic decomposition of NO over Cu-Os/13X has been carried out in a tubular fixed bed reactor at atmospheric pressure and the results were compared with literature data performed by high-throughput screening (HTS). The activity and durability of Cu-Os/13X prepared by conventional ion-exchange method have been investigated in the presence of H 2 O and SO 2 . It was found that Cu-Os/13X prepared by ion-exchange shows a high activity in a wide temperature range in selective catalytic reduction (SCR) of NO with C 3 H 6 compared to Cu/13X, proving the existence of more NO adsorption site on Cu-Os/13X. However, Cu-Os/13X exhibited low activity in the presence of water, and was quite different from the result reported in literature. SO 2 resistance is also low and does not recover its original activity when the SO 2 was blocked in the feed gas stream. This result suggested that catalytic activity between combinatorial screening and conventional testing should be compared to confirm the validity of high-throughput screening

  4. Adsorption of guaiacol on Fe (110) and Pd (111) from first principles

    Science.gov (United States)

    Hensley, Alyssa J. R.; Wang, Yong; McEwen, Jean-Sabin

    2016-06-01

    The catalytic properties of surfaces are highly dependent upon the effect said surfaces have on the geometric and electronic structure of adsorbed reactants, products, and intermediates. It is therefore crucial to have a surface-level understanding of the adsorption of the key species in a reaction in order to design active and selective catalysts. Here, we study the adsorption of guaiacol on Fe (110) and Pd (111) using dispersion-corrected density functional theory calculations as both of these metals are of interest as hydrodeoxygenation catalysts for the conversion of bio-oils to useable biofuels. Both vertical (via the oxygen functional groups) and horizontal (via the aromatic ring) adsorption configurations were examined and the resulting adsorption and molecular distortion energies showed that the vertical sites were only physisorbed while the horizontal sites were chemisorbed on both metal surfaces. A comparison of guaiacol's horizontal adsorption on Fe (110) and Pd (111) showed that guaiacol had a stronger adsorption on Pd (111) while the Fe (110) surface distorted the Csbnd O bonds to a greater degree. Electronic analyses on the horizontal systems showed that the greater adsorption strength for guaiacol on Pd (111) was likely due to the greater charge transfer between the aromatic ring and the surface Pd atoms. Additionally, the greater distortion of the Csbnd O bonds in adsorbed guaiacol on Fe (110) is likely due to the greater degree of interaction between the oxygen and surface Fe atoms. Overall, our results show that the Fe (110) surface has a greater degree of interaction with the functional groups and the Pd (111) surface has a greater degree of interaction with the aromatic ring.

  5. Platinum adsorption onto graphene and oxidized graphene: A quantum mechanics study

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, S.A.; Jahanshahi, M. [Nanotechnology Research Institute, School of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of); Ahangari, M. Ghorbanzadeh, E-mail: ghorbanzadeh.morteza@gmail.com [Department of Mechanical Engineering, Faculty of Engineering and Technology, University of Mazandaran, Babolsar (Iran, Islamic Republic of)

    2017-04-01

    Density functional theory based on first-principle calculations was used to examine platinum-supported oxidized graphene as a beneficial nanomaterial in terms of its catalytic activity and utility for contaminant removal and disinfecting polluted solutions in both domestic and industrial applications. The first step was to select the most appropriate available computing package to apply the supercell technique, which would provide a better representation of a large and real graphene slab. Using OpenMX was less time-consuming after we enforced a basis set for valence electrons to avoid an all-electron calculation, and this had very slight and negligible effect on the accuracy of the calculations. The OpenMX software was selected to perform forward steps of investigating changes in the properties such as adsorption energy and ground state structure of the complexes made by the adsorption of a platinum atom on the surface of pristine graphene (Pt/PG) and oxidized graphene (Pt/OG), which had the lowest adsorption energy of −5.28 eV. Moreover, we examined the effect of Pt atom adsorption on the surface and between two layers of graphene. Our results show that, there was no specific change observed in mentioned properties of Pt atom adsorption on bilayer graphene in comparison with single layer. - Highlights: • Pt adsorption on graphene and oxidized graphene was examined. • We have also considered the effect of the layered graphene on the Pt adsorption. • We first compared two different DFT calculation codes, SIESTA and OpenMX. • We then used ORCA to validate and select a suitable computation package for this study.

  6. Theoretical study of H- stripping with a wiggler magnet

    International Nuclear Information System (INIS)

    Hutson, R.L.

    1991-01-01

    The first step for injecting protons into the LAMPF Proton Storage Ring (PSR) at LANL is to strip a beam of 800-MeV H - ions to H 0 with a 1.8-T dipole magnet. Because of the finite lifetime of energetic H - ions in the magnetic field, their trajectories bend before stripping causing the angular spread of the beam, and therefore its emittance, to grow during the stripping process. In the case of the PSR, the horizontal beam emittance grows by a factor of roughly three during injection. As a consequence, beam losses in the ring are significantly greater than they would be if there were not emittance growth. A speculative technique is proposed in which the beam divergence growth and resulting emittance growth is reduced by stripping the H - in a wiggler magnet whose transverse field alternates in direction as a function of position along the beam axis. The wiggler field configuration is adjusted so that the angular beam spread introduced during passage through one unidirectional-field increment of path is relatively small and so that 99.99% of the beam is stripped after passing through the whole magnet. With careful field design the net added angular beam spread is reduced because the incremental angular spreads are painted back and forth over the same small range. In the hypothetical case described, the calculated emittance growth and beam loss increase are significantly smaller than those calculated for a conventional stripper magnet. 3 refs., 3 figs

  7. Characterization and Calibration of Large Area Resistive Strip Micromegas Detectors

    CERN Document Server

    Losel, Philipp Jonathan; The ATLAS collaboration

    2015-01-01

    Resisitve strip Micromegas detectors behave discharge tolerant. They have been tested extensively as smaller detectors of about 10 x 10 cm$^2$ in size and they work reliably at high rates of 100\\,kHz/cm$^2$ and above. Tracking resolutions well below 100\\,$\\mu$m have been observed for 100 GeV muons and pions. Micromegas detectors are meanwhile proposed as large area muon precision trackers of 2-3\\,m$^2$ in size. To investigate possible differences between small and large detectors, a 1\\,m$^2$ detector with 2048 resistive strips at a pitch of 450 $\\mu$m was studied in the LMU Cosmic Ray Facility (CRF) using two 4 $\\times$ 2.2 m$^2$ large Monitored Drift Tube (MDT) chambers for cosmic muon reference tracking. Segmentation of the resistive strip anode plane in 57.6\\,mm x 95\\,mm large areas has been realized by the readout of 128 strips with one APV25 chip each and by 11 95\\,mm broad trigger scintillators placed along the readout strips.\\\\ This allows for mapping of homogenity in pulse height and efficiency, deter...

  8. Characterization and Calibration of Large Area Resistive Strip Micromegas Detectors

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00389527; The ATLAS collaboration

    2016-01-01

    Resistive strip Micromegas detectors are discharge tolerant. They have been tested extensively as small detectors of about 10 x 10 cm$^2$ in size and they work reliably at high rates of 100 kHz/cm$^2$ and above. Tracking resolution well below 100 $\\mu$m has been observed for 100 GeV muons and pions. Micromegas detectors are meanwhile proposed as large area muon precision trackers of 2-3 m$^2$ in size. To investigate possible differences between small and large detectors, a 1 m$^2$ detector with 2048 resistive strips at a pitch of 450 $\\mu$m was studied in the LMU Cosmic Ray Measurement Facility (CRMF) using two 4 $\\times$ 2.2 m$^2$ large Monitored Drift Tube (MDT) chambers for cosmic muon reference tracking. A segmentation of the resistive strip anode plane in 57.6 mm x 93 mm large areas has been realized by the readout of 128 strips with one APV25 chip each and by eleven 93 mm broad trigger scintillators placed along the readout strips. This allows for mapping of homogeneity in pulse height and efficiency, d...

  9. Thermodynamic features of dioxins’ adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Prisciandaro, Marina [Department of Industrial and Information Engineering and of Economics, University of L’Aquila, Viale Giovanni Gronchi 18, L’Aquila 67100 (Italy); Piemonte, Vincenzo, E-mail: v.piemonte@unicampus.it [Faculty of Engineering, University Campus Biomedico of Rome, Via Alvaro del Portillo 21, Rome 00128 (Italy); Mazziotti di Celso, Giuseppe [Faculty of Bioscience, University of Teramo, Via R. Balzarini, 1, 64100 Teramo (Italy); Ronconi, Silvia [Arta Abruzzo, Department of L’Aquila, Bazzano (AQ), 67100 L’Aquila (Italy); Capocelli, Mauro [Faculty of Engineering, University Campus Biomedico of Rome, Via Alvaro del Portillo 21, Rome 00128 (Italy)

    2017-02-15

    Highlights: • We develop the P-T diagram for six PCDD. • We derive theoretical adsorption isotherms according to the Langmuir’s model. • We calculate K and w{sub max} values for several temperatures. • We estimate the adsorption heat with a good agreement with literature data. - Abstract: In this paper, the six more poisonous species among all congeners of dioxin group are taken into account, and the P-T diagram for each of them is developed. Starting from the knowledge of vapour tensions and thermodynamic parameters, the theoretical adsorption isotherms are calculated according to the Langmuir’s model. In particular, the Langmuir isotherm parameters (K and w{sub max}) have been validated through the estimation of the adsorption heat (ΔH{sub ads}), which varies in the range 20–24 kJ/mol, in agreement with literature values. This result will allow to put the thermodynamical basis for a rational design of different process units devoted to dioxins removal.

  10. Adsorptive storage of natural gas

    International Nuclear Information System (INIS)

    Yan, Song; Lang, Liu; Licheng, Ling

    2001-01-01

    The Adsorbed Natural Gas (ANG) storage technology is reviewed. The present status, theoretical limits and operational problems are discussed. Natural gas (NG) has a considerable advantage over conventional fuels both from an environmental point of view and for its natural abundance. However, as well known, it has a two fold disadvantage compared with liquid fuels: it is relatively expensive to transport from the remote areas, and its energy density (heat of combustion/volume) is low. All these will restrict its use. Compressed natural gas (CNG) may be a solution, but high pressures are needed (up to 25 MPa) for use in natural-gas fueled vehicles, and the large cost of the cylinders for storage and the high-pressure facilities necessary limit the practical use of CNG. Alternatively, adsorbed natural gas (ANG) at 3 - 4 MPa offers a very high potential for exploitation in both transport and large-scale applications. At present, research about this technology mainly focuses on: to make adsorbents with high methane adsorption capacity; to make clear the effects of heat of adsorption and the effect of impurities in natural gas on adsorption and desorption capacity. This paper provides an overview of current technology and examines the relations between fundamentals of adsorption and ANG storage. (authors)

  11. ADSORPTION OF SURFACTANT ON CLAYS

    Science.gov (United States)

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  12. Immunoglobulin adsorption on modified surfaces

    NARCIS (Netherlands)

    Bremer, M.G.E.G.

    2001-01-01

    Preservation of biological functioning of proteins during immobilisation is of special interest in various biomedical and biotechnical applications. In industry physical adsorption of immunoglobulins (IgGs) onto solid surfaces is still the predominant immobilisation procedure because it is

  13. Thermodynamic Properties of Chromium Adsorption by Sediments ...

    African Journals Online (AJOL)

    The adsorption of Chromium from aqueous solution using river Watari sediment as an adsorbent was modeled. The influence of initial pH, solution temperature, adsorbent and adsorbate concentrations on the adsorption efficiency was investigated using batch equilibrium assays. From the results obtained for the adsorption ...

  14. Competitive Adsorption of Chloroform and Bromoform Using ...

    African Journals Online (AJOL)

    The results obtained were checked with Freundlich adsorption isotherm model. This model expresses well adsorption of one THM species in the presence of another with R2 > 0.95. Based on the model, adsorption capacity of Calgon F200 and Norit GCN1240 were found higher for bromoform than chloroform. Calgon F200 ...

  15. Environmentally benign working pairs for adsorption refrigeration

    International Nuclear Information System (INIS)

    Cui Qun; Tao Gang; Chen Haijun; Guo Xinyue; Yao Huqing

    2005-01-01

    This paper begins from adsorption working pairs: water and ethanol were selected as refrigerants; 13x molecular sieve, silica gel, activated carbon, adsorbent NA and NB, proposed by authors, were selected as adsorbents, and the performance of adsorption working pairs in adsorption refrigeration cycle was studied. The adsorption isotherms of adsorbents (NA and NB) were obtained by high-vacuum gravimetric method. Desorption properties of adsorbents were analyzed and compared by thermal analysis method. The performance of adsorption refrigeration was studied on simulation device of adsorption refrigeration cycle. After presentation of adsorption isotherms, the thermodynamic performance for their use in adsorption refrigeration system was calculated. The results show: (1) the maximum adsorption capacity of water on adsorbent NA reaches 0.7 kg/kg, and the maximum adsorption capacity of ethanol on adsorbent NB is 0.68 kg/kg, which is three times that of ethanol on activated carbon, (2) the refrigeration capacity of NA-water working pair is 922 kJ/kg, the refrigeration capacity of NB-ethanol is 2.4 times that of activated carbon-methanol, (3) as environmental friendly and no public hazard adsorption working pair, NA-H 2 O and NB-ethanol can substitute activated carbon-methanol in adsorption refrigeration system using low-grade heat source

  16. Catalytic modification of cellulose and hemicellulose - Sugarefine

    Energy Technology Data Exchange (ETDEWEB)

    Repo, T. [Helsinki Univ. (Finland),Laboratory of Inorganic Chemistry], email: timo.repo@helsinki.fi

    2012-07-01

    The main goal of the project is to develop catalytic methods for the modification of lignocellulose-based saccharides in the biorefineries. The products of these reactions could be used for example as biofuel components, raw materials for the chemical industry, solvents and precursors for biopolymers. The catalyst development aims at creating efficient, selective and green catalytic methods for profitable use in biorefineries. The project is divided in three work packages: In WP1 (Catalytic dehydration of cellulose) the aim is at developing non-toxic, efficient methods for the catalytic dehydration of cellulose the target molecule being here 5-hydroxymethylfurfural (5-HMF). 5-HMF is an interesting platform chemical for the production of fuel additives, solvents and polymers. In WP2 (Catalytic reduction), the objective of the catalytic reduction studies is to produce commercially interesting monofunctional chemicals, such as 1-butanol or 2-methyltetrahydrofuran (2-MeTHF). In WP3 (Catalytic oxidation), the research focuses on developing a green and efficient oxidation method for producing acids. Whereas acetic and formic acids are bulk chemicals, diacids such as glucaric and xylaric acids are valuable specialty chemicals for detergent, polymer and food production.

  17. Phonon thermal conductance of disordered graphene strips with armchair edges

    International Nuclear Information System (INIS)

    Shi Lipeng; Xiong Shijie

    2009-01-01

    Based on the model of lattice dynamics together with the transfer matrix technique, we investigate the thermal conductances of phonons in quasi-one-dimensional disordered graphene strips with armchair edges using Landauer formalism for thermal transport. It is found that the contributions to thermal conductance from the phonon transport near von Hove singularities is significantly suppressed by the presence of disorder, on the contrary to the effect of disorder on phonon modes in other frequency regions. Besides the magnitude, for different widths of the strips, the thermal conductance also shows different temperature dependence. At low temperatures, the thermal conductance displays quantized features of both pure and disordered graphene strips implying that the transmission of phonon modes at low frequencies are almost unaffected by the disorder

  18. Efficiency measurements for 3D silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Parzefall, Ulrich, E-mail: ulrich.parzefall@physik.uni-freiburg.d [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Dalla Betta, Gian-Franco [INFN Trento and Universita di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Boscardin, Maurizio [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Eckert, Simon [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Eklund, Lars; Fleta, Celeste [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Jakobs, Karl; Koehler, Michael; Kuehn, Susanne; Pahn, Gregor [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Parkes, Chris; Pennicard, David [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Ronchin, Sabina [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Zoboli, Andrea [INFN Trento and Universita di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Zorzi, Nicola [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy)

    2010-11-01

    Silicon strip detectors are widely used as part of the inner tracking layers in particle physics experiments. For applications at the luminosity upgrade of the Large Hadron Collider (LHC), the sLHC, silicon detectors with extreme radiation hardness are required. The 3D detector design, where electrodes are processed from underneath the strips into the silicon bulk material, provides a way to enhance the radiation tolerance of standard planar silicon strip detectors. Detectors with several innovative 3D designs that constitute a simpler and more cost-effective processing than the 3D design initially proposed were connected to read-out electronics from LHC experiments and subsequently tested. Results on the amount of charge collected, the noise and the uniformity of charge collection are given.

  19. Compton recoil electron tracking with silicon strip detectors

    International Nuclear Information System (INIS)

    O'Neill, T.J.; Ait-Ouamer, F.; Schwartz, I.; Tumer, O.T.; White, R.S.; Zych, A.D.

    1992-01-01

    The application of silicon strip detectors to Compton gamma ray astronomy telescopes is described in this paper. The Silicon Compton Recoil Telescope (SCRT) tracks Compton recoil electrons in silicon strip converters to provide a unique direction for Compton scattered gamma rays above 1 MeV. With strip detectors of modest positional and energy resolutions of 1 mm FWHM and 3% at 662 keV, respectively, 'true imaging' can be achieved to provide an order of magnitude improvement in sensitivity to 1.6 x 10 - 6 γ/cm 2 -s at 2 MeV. The results of extensive Monte Carlo calculations of recoil electrons traversing multiple layers of 200 micron silicon wafers are presented. Multiple Coulomb scattering of the recoil electron in the silicon wafer of the Compton interaction and the next adjacent wafer is the basic limitation to determining the electron's initial direction

  20. Performance studies of the CMS Strip Tracker before installation

    CERN Document Server

    Adam, Wolfgang; Dragicevic, Marko; Friedl, Markus; Fruhwirth, R; Hansel, S; Hrubec, Josef; Krammer, Manfred; Oberegger, Margit; Pernicka, Manfred; Schmid, Siegfried; Stark, Roland; Steininger, Helmut; Uhl, Dieter; Waltenberger, Wolfgang; Widl, Edmund; Van Mechelen, Pierre; Cardaci, Marco; Beaumont, Willem; de Langhe, Eric; de Wolf, Eddi A; Delmeire, Evelyne; Hashemi, Majid; Bouhali, Othmane; Charaf, Otman; Clerbaux, Barbara; Dewulf, Jean-Paul; Elgammal, Sherif; Hammad, Gregory Habib; de Lentdecker, Gilles; Marage, Pierre Edouard; Vander Velde, Catherine; Vanlaer, Pascal; Wickens, John; Adler, Volker; Devroede, Olivier; De Weirdt, Stijn; D'Hondt, Jorgen; Goorens, Robert; Heyninck, Jan; Maes, Joris; Mozer, Matthias Ulrich; Tavernier, Stefaan; Van Lancker, Luc; Van Mulders, Petra; Villella, Ilaria; Wastiels, C; Bonnet, Jean-Luc; Bruno, Giacomo; De Callatay, Bernard; Florins, Benoit; Giammanco, Andrea; Gregoire, Ghislain; Keutgen, Thomas; Kcira, Dorian; Lemaitre, Vincent; Michotte, Daniel; Militaru, Otilia; Piotrzkowski, Krzysztof; Quertermont, L; Roberfroid, Vincent; Rouby, Xavier; Teyssier, Daniel; Daubie, Evelyne; Anttila, Erkki; Czellar, Sandor; Engstrom, Pauli; Harkonen, J; Karimaki, V; Kostesmaa, J; Kuronen, Auli; Lampen, Tapio; Linden, Tomas; Luukka, Panja-Riina; Maenpaa, T; Michal, Sebastien; Tuominen, Eija; Tuominiemi, Jorma; Ageron, Michel; Baulieu, Guillaume; Bonnevaux, Alain; Boudoul, Gaelle; Chabanat, Eric; Chabert, Eric Christian; Chierici, Roberto; Contardo, Didier; Della Negra, Rodolphe; Dupasquier, Thierry; Gelin, Georges; Giraud, Noël; Guillot, Gérard; Estre, Nicolas; Haroutunian, Roger; Lumb, Nicholas; Perries, Stephane; Schirra, Florent; Trocme, Benjamin; Vanzetto, Sylvain; Agram, Jean-Laurent; Blaes, Reiner; Drouhin, Frédéric; Ernenwein, Jean-Pierre; Fontaine, Jean-Charles; Berst, Jean-Daniel; Brom, Jean-Marie; Didierjean, Francois; Goerlach, Ulrich; Graehling, Philippe; Gross, Laurent; Hosselet, J; Juillot, Pierre; Lounis, Abdenour; Maazouzi, Chaker; Olivetto, Christian; Strub, Roger; Van Hove, Pierre; Anagnostou, Georgios; Brauer, Richard; Esser, Hans; Feld, Lutz; Karpinski, Waclaw; Klein, Katja; Kukulies, Christoph; Olzem, Jan; Ostapchuk, Andrey; Pandoulas, Demetrios; Pierschel, Gerhard; Raupach, Frank; Schael, Stefan; Schwering, Georg; Sprenger, Daniel; Thomas, Maarten; Weber, Markus; Wittmer, Bruno; Wlochal, Michael; Beissel, Franz; Bock, E; Flugge, G; Gillissen, C; Hermanns, Thomas; Heydhausen, Dirk; Jahn, Dieter; Kaussen, Gordon; Linn, Alexander; Perchalla, Lars; Poettgens, Michael; Pooth, Oliver; Stahl, Achim; Zoeller, Marc Henning; Buhmann, Peter; Butz, Erik; Flucke, Gero; Hamdorf, Richard Helmut; Hauk, Johannes; Klanner, Robert; Pein, Uwe; Schleper, Peter; Steinbruck, G; Blum, P; De Boer, Wim; Dierlamm, Alexander; Dirkes, Guido; Fahrer, Manuel; Frey, Martin; Furgeri, Alexander; Hartmann, Frank; Heier, Stefan; Hoffmann, Karl-Heinz; Kaminski, Jochen; Ledermann, Bernhard; Liamsuwan, Thiansin; Muller, S; Muller, Th; Schilling, Frank-Peter; Simonis, Hans-Jürgen; Steck, Pia; Zhukov, Valery; Cariola, P; De Robertis, Giuseppe; Ferorelli, Raffaele; Fiore, Luigi; Preda, M; Sala, Giuliano; Silvestris, Lucia; Tempesta, Paolo; Zito, Giuseppe; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Giordano, Domenico; Maggi, Giorgio; Manna, Norman; My, Salvatore; Selvaggi, Giovanna; Albergo, Sebastiano; Chiorboli, Massimiliano; Costa, Salvatore; Galanti, Mario; Giudice, Nunzio; Guardone, Nunzio; Noto, Francesco; Potenza, Renato; Saizu, Mirela Angela; Sparti, V; Sutera, Concetta; Tricomi, Alessia; Tuve, Cristina; Brianzi, Mirko; Civinini, Carlo; Maletta, Fernando; Manolescu, Florentina; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Broccolo, B; Ciulli, Vitaliano; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Genta, Chiara; Landi, Gregorio; Lenzi, Piergiulio; Macchiolo, Anna; Magini, Nicolo; Parrini, Giuliano; Scarlini, Enrico; Cerati, Giuseppe Benedetto; Azzi, Patrizia; Bacchetta, Nicola; Candelori, Andrea; Dorigo, Tommaso; Kaminsky, A; Karaevski, S; Khomenkov, Volodymyr; Reznikov, Sergey; Tessaro, Mario; Bisello, Dario; De Mattia, Marco; Giubilato, Piero; Loreti, Maurizio; Mattiazzo, Serena; Nigro, Massimo; Paccagnella, Alessandro; Pantano, Devis; Pozzobon, Nicola; Tosi, Mia; Bilei, Gian Mario; Checcucci, Bruno; Fano, Livio; Servoli, Leonello; Ambroglini, Filippo; Babucci, Ezio; Benedetti, Daniele; Biasini, Maurizio; Caponeri, Benedetta; Covarelli, Roberto; Giorgi, Marco; Lariccia, Paolo; Mantovani, Giancarlo; Marcantonini, Marta; Postolache, Vasile; Santocchia, Attilio; Spiga, Daniele; Bagliesi, Giuseppe; Balestri, Gabriele; Berretta, Luca; Bianucci, S; Boccali, Tommaso; Bosi, Filippo; Bracci, Fabrizio; Castaldi, Rino; Ceccanti, Marco; Cecchi, Roberto; Cerri, Claudio; Cucoanes, Andi Sebastian; Dell'Orso, Roberto; Dobur, Didar; Dutta, Suchandra; Giassi, Alessandro; Giusti, Simone; Kartashov, Dmitry; Kraan, Aafke; Lomtadze, Teimuraz; Lungu, George-Adrian; Magazzu, Guido; Mammini, Paolo; Mariani, Filippo; Martinelli, Giovanni; Moggi, Andrea; Palla, Fabrizio; Palmonari, Francesco; Petragnani, Giulio; Profeti, Alessandro; Raffaelli, Fabrizio; Rizzi, Domenico; Sanguinetti, Giulio; Sarkar, Subir; Sentenac, Daniel; Serban, Alin Titus; Slav, Adrian; Soldani, A; Spagnolo, Paolo; Tenchini, Roberto; Tolaini, Sergio; Venturi, Andrea; Verdini, Piero Giorgio; Vos, Marcel; Zaccarelli, Luciano; Avanzini, Carlo; Basti, Andrea; Benucci, Leonardo; Bocci, Andrea; Cazzola, Ugo; Fiori, Francesco; Linari, Stefano; Massa, Maurizio; Messineo, Alberto; Segneri, Gabriele; Tonelli, Guido; Azzurri, Paolo; Bernardini, Jacopo; Borrello, Laura; Calzolari, Federico; Foa, Lorenzo; Gennai, Simone; Ligabue, Franco; Petrucciani, Giovanni; Rizzi, Andrea; Yang, Zong-Chang; Benotto, Franco; Demaria, Natale; Dumitrache, Floarea; Farano, R; Borgia, Maria Assunta; Castello, Roberto; Costa, Marco; Migliore, Ernesto; Romero, Alessandra; Abbaneo, Duccio; Abbas, M; Ahmed, Ijaz; Akhtar, I; Albert, Eric; Bloch, Christoph; Breuker, Horst; Butt, Shahid Aleem; Buchmuller, Oliver; Cattai, Ariella; Delaere, Christophe; Delattre, Michel; Edera, Laura Maria; Engstrom, Pauli; Eppard, Michael; Gateau, Maryline; Gill, Karl; Giolo-Nicollerat, Anne-Sylvie; Grabit, Robert; Honma, Alan; Huhtinen, Mika; Kloukinas, Kostas; Kortesmaa, Jarmo; Kottelat, Luc-Joseph; Kuronen, Auli; Leonardo, Nuno; Ljuslin, Christer; Mannelli, Marcello; Masetti, Lorenzo; Marchioro, Alessandro; Mersi, Stefano; Michal, Sebastien; Mirabito, Laurent; Muffat-Joly, Jeannine; Onnela, Antti; Paillard, Christian; Pal, Imre; Pernot, Jean-Francois; Petagna, Paolo; Petit, Patrick; Piccut, C; Pioppi, Michele; Postema, Hans; Ranieri, Riccardo; Ricci, Daniel; Rolandi, Gigi; Ronga, Frederic Jean; Sigaud, Christophe; Syed, A; Siegrist, Patrice; Tropea, Paola; Troska, Jan; Tsirou, Andromachi; Vander Donckt, Muriel; Vasey, François; Alagoz, Enver; Amsler, Claude; Chiochia, Vincenzo; Regenfus, Christian; Robmann, Peter; Rochet, Jacky; Rommerskirchen, Tanja; Schmidt, Alexander; Steiner, Stefan; Wilke, Lotte; Church, Ivan; Cole, Joanne; Coughlan, John A; Gay, Arnaud; Taghavi, S; Tomalin, Ian R; Bainbridge, Robert; Cripps, Nicholas; Fulcher, Jonathan; Hall, Geoffrey; Noy, Matthew; Pesaresi, Mark; Radicci, Valeria; Raymond, David Mark; Sharp, Peter; Stoye, Markus; Wingham, Matthew; Zorba, Osman; Goitom, Israel; Hobson, Peter R; Reid, Ivan; Teodorescu, Liliana; Hanson, Gail; Jeng, Geng-Yuan; Liu, Haidong; Pasztor, Gabriella; Satpathy, Asish; Stringer, Robert; Mangano, Boris; Affolder, K; Affolder, T; Allen, Andrea; Barge, Derek; Burke, Samuel; Callahan, D; Campagnari, Claudio; Crook, A; D'Alfonso, Mariarosaria; Dietch, J; Garberson, Jeffrey; Hale, David; Incandela, H; Incandela, Joe; Jaditz, Stephen; Kalavase, Puneeth; Kreyer, Steven Lawrence; Kyre, Susanne; Lamb, James; Mc Guinness, C; Mills, C; Nguyen, Harold; Nikolic, Milan; Lowette, Steven; Rebassoo, Finn; Ribnik, Jacob; Richman, Jeffrey; Rubinstein, Noah; Sanhueza, S; Shah, Yousaf Syed; Simms, L; Staszak, D; Stoner, J; Stuart, David; Swain, Sanjay Kumar; Vlimant, Jean-Roch; White, Dean; Ulmer, Keith; Wagner, Stephen Robert; Bagby, Linda; Bhat, Pushpalatha C; Burkett, Kevin; Cihangir, Selcuk; Gutsche, Oliver; Jensen, Hans; Johnson, Mark; Luzhetskiy, Nikolay; Mason, David; Miao, Ting; Moccia, Stefano; Noeding, Carsten; Ronzhin, Anatoly; Skup, Ewa; Spalding, William J; Spiegel, Leonard; Tkaczyk, Slawek; Yumiceva, Francisco; Zatserklyaniy, Andriy; Zerev, E; Anghel, Ioana Maria; Bazterra, Victor Eduardo; Gerber, Cecilia Elena; Khalatian, S; Shabalina, Elizaveta; Baringer, Philip; Bean, Alice; Chen, Jie; Hinchey, Carl Louis; Martin, Christophe; Moulik, Tania; Robinson, Richard; Gritsan, Andrei; Lae, Chung Khim; Tran, Nhan Viet; Everaerts, Pieter; Hahn, Kristan Allan; Harris, Philip; Nahn, Steve; Rudolph, Matthew; Sung, Kevin; Betchart, Burton; Demina, Regina; Gotra, Yury; Korjenevski, Sergey; Miner, Daniel Carl; Orbaker, Douglas; Christofek, Leonard; Hooper, Ryan; Landsberg, Greg; Nguyen, Duong; Narain, Meenakshi; Speer, Thomas; Tsang, Ka Vang

    2009-01-01

    In March 2007 the assembly of the Silicon Strip Tracker was completed at the Tracker Integration Facility at CERN. Nearly 15% of the detector was instrumented using cables, fiber optics, power supplies, and electronics intended for the operation at the LHC. A local chiller was used to circulate the coolant for low temperature operation. In order to understand the efficiency and alignment of the strip tracker modules, a cosmic ray trigger was implemented. From March through July 4.5 million triggers were recorded. This period, referred to as the Sector Test, provided practical experience with the operation of the Tracker, especially safety, data acquisition, power, and cooling systems. This paper describes the performance of the strip system during the Sector Test, which consisted of five distinct periods defined by the coolant temperature. Significant emphasis is placed on comparisons between the data and results from Monte Carlo studies.