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Sample records for flow injection determination

  1. Spectrofluorimetric determination of cerium by flow injection analysis

    International Nuclear Information System (INIS)

    Liu Shaorong; Meng Jian; Liu Wenhua

    1990-01-01

    A spectrofluorimetric method for the determination of cerium (λ ex/em:251/365 nm) in hydrochloric acid solution by flow injection analysis is presented. It has well developed the normal spectrofluorimetric method for determination of cerium and has made: 1, the determination procedure shortened; 2, the determination speed increased to about 180 samples per hour; 3, the determination range widened to 0.05-100.0 ppm CeO 2 , abouot two times as wide as the normal spectrofluorimetric method; and 4, the relative standard deviation lessened (about 0.47% for 0.1 ppm CeO 2 , n = 13)

  2. Stopped-flow injection spectrophotometric method for determination of chlorate in soil

    OpenAIRE

    Jaroon Jakmunee

    2008-01-01

    A stopped-flow injection (FI) spectrophotometric procedure based on iodometric reaction for the determination of chlorate has been developed. Standard/sample was injected into a stream of potassium iodide solution and then merged with a stream of hydrochloric acid solution to produce triiodide. By stopping the flow while the sample zone is being in a mixing coil, a slow reaction of chlorate with iodide in acidic medium was promoted to proceed with minimal dispersion of the triiodide product z...

  3. Determination of albumin in bronchoalveolar lavage fluid by flow-injection fluorometry using chromazurol S.

    Science.gov (United States)

    Sato, Takaji; Saito, Yoshihiro; Chikuma, Masahiko; Saito, Yutaka; Nagai, Sonoko

    2008-03-01

    A highly sensitive flow injection fluorometry for the determination of albumin was developed and applied to the determination of albumin in human bronchoalveolar lavage fluids (BALF). This method is based on binding of chromazurol S (CAS) to albumin. The calibration curve was linear in the range of 5-200 microg/ml of albumin. A highly linear correlation (r=0.986) was observed between the albumin level in BALF samples (n=25) determined by the proposed method and by a conventional fluorometric method using CAS (CAS manual method). The IgG interference was lower in the CAS flow injection method than in the CAS manual method. The albumin level in BALF collected from healthy volunteers (n=10) was 58.5+/-13.1 microg/ml. The albumin levels in BALF samples obtained from patients with sarcoidosis and idiopathic pulmonary fibrosis were increased. This finding shows that the determination of albumin levels in BALF samples is useful for investigating lung diseases and that CAS flow injection method is promising in the determination of trace albumin in BALF samples, because it is sensitive and precise.

  4. Home-Made Micro Valve for Determining Malachite Green Dye by Flow Injection Analysis

    Directory of Open Access Journals (Sweden)

    Amal Saadoon Majeed

    2017-07-01

    Full Text Available The research is included studying and designing micro flow injection system which is characterized with rapidity, simplicity, and low cost for the determination of green malachite dye. The study of flow rate of carrier stream, repeatability, dispersion coefficient, and calibration graph are conducted. It is found that the optimum conditions for the determination of mentioned dye are flow rate 4.200 mL/min, sampling rate 102 sample/h, limit of detection 0.05 ppm, linear range (0.05-18.00 ppm with linearity (R2=0.9700, RSD is 0.355, the repeatability for seven successive injections is studied for the two concentrations 5 ppm and 12 ppm, and the dispersion coefficient values are 1.73 and 1.28 at the two concentrations 2 ppm and 9 ppm respectively.

  5. The determination, by flow-injection analysis, of iron, sulphate, silver and cadmium

    International Nuclear Information System (INIS)

    Jones, E.A.

    1983-01-01

    This report describes the spectrophotometric determination by flow-injection analysis including, where necessary, liquid-liquid extraction of iron with 1,10-phenanthroline; of sulphate by its catalytic effect on the methylthymol blue-zirconium reaction; of silver with bromopyrogallol red and 1,10-phenanthroline; and of cadmium with dithizone. Optimum conditions for each system are established, and sensitivities and ranges of determination are given

  6. O-(β-hydroxyethylrutosides determination by micellar flow injection (FI-spectrofluorimetry

    Directory of Open Access Journals (Sweden)

    Cecilia Mariana Peralta

    2014-12-01

    Full Text Available A simple, eco-friendly, sensitive and economic flow injection spectrofluorimetric method was developed for the determination of O-(β-hydroxyethylrutosides. The procedure was based on the use of an anionic surfactant such as sodium dodecyl sulfate to provide an appreciable O-(β-hydroxyethylrutosides fluorescence enhancement, increasing considerably the sensitivity of detection. All the variables affecting the fluorescence intensity were studied and optimized. The flow rate was 5 mL/min with detection at 450 nm (after excitation at 346 nm. A linear correlation between drug amount and peak area was established for O-(β-hydroxyethylrutosides in the range of 0.01–200 µg/mL with a detection limit of 0.001 µg/mL (s/n=3. Validation processes were performed by recovering studies with satisfactory results. The new methodology can be employed for the routine analysis of O-(β-hydroxyethylrutosides in bulks as well as in commercial formulations. Keywords: O-(β-hydroxyethylrutosides, Micellar enhancement, Flow injection, Spectrofluorimetry, Pharmaceuticals

  7. Flow injection analysis using carbon film resistor electrodes for amperometric determination of ambroxol.

    Science.gov (United States)

    Felix, Fabiana S; Brett, Christopher M A; Angnes, Lúcio

    2008-06-30

    Flow injection analysis (FIA) using a carbon film sensor for amperometric detection was explored for ambroxol analysis in pharmaceutical formulations. The specially designed flow cell designed in the lab generated sharp and reproducible current peaks, with a wide linear dynamic range from 5x10(-7) to 3.5x10(-4) mol L(-1), in 0.1 mol L(-1) sulfuric acid electrolyte, as well as high sensitivity, 0.110 Amol(-1) L cm(-2) at the optimized flow rate. A detection limit of 7.6x10(-8) mol L(-1) and a sampling frequency of 50 determinations per hour were achieved, employing injected volumes of 100 microL and a flow rate of 2.0 mL min(-1). The repeatability, expressed as R.S.D. for successive and alternated injections of 6.0x10(-6) and 6.0x10(-5) mol L(-1) ambroxol solutions, was 3.0 and 1.5%, respectively, without any noticeable memory effect between injections. The proposed method was applied to the analysis of ambroxol in pharmaceutical samples and the results obtained were compared with UV spectrophotometric and acid-base titrimetric methods. Good agreement between the results utilizing the three methods and the labeled values was achieved, corroborating the good performance of the proposed electrochemical methodology for ambroxol analysis.

  8. Spectrophotometric flow injection catalytic determination of molybdenum in plant digest using ion exchange resin

    International Nuclear Information System (INIS)

    Pessenda, L.C.R.

    1987-03-01

    A spectrophotometric flow injection analytical method based on the catalytic action of molybdenum on the oxidation of iodide by hydrogen peroxide in acidic medium is proposed for the molybdenum determination in plant digests. A cation exchange resin column is incorporated into a flow injection system for removal of interferents. The following system variables were investigated and optimized: reagent concentrations, sample injection volume, mixing and reaction coil lengths, temperature, sampling time, pumping rate and concentration of eluting agents. The effects of interfering species and of the acidity of samples on the molybdenum retention by the ion exchange resin column were investigated. The proposed method is characterized by good precision (r.s.d. (2.0%), a sampling rate of about 40 samples per hour, and permits the determination of molybdenum in plant digests in the range 1.0 to 40.0 μg/l. The results compare well with those obtained by graphite furnace atomic absorption spectrometry. (author) [pt

  9. Stopped-flow injection spectrophotometric method for determination of chlorate in soil

    Directory of Open Access Journals (Sweden)

    Jaroon Jakmunee

    2008-06-01

    Full Text Available A stopped-flow injection (FI spectrophotometric procedure based on iodometric reaction for the determination of chlorate has been developed. Standard/sample was injected into a stream of potassium iodide solution and then merged with a stream of hydrochloric acid solution to produce triiodide. By stopping the flow while the sample zone is being in a mixing coil, a slow reaction of chlorate with iodide in acidic medium was promoted to proceed with minimal dispersion of the triiodide product zone. When the flow started again, a concentrated product zone was pushed into a flow cell and a signal profile due to light absorption of the product was recorded. Employing a lab-built semi-automatic stopped-FI analyser, the analysis can be performed with higher degree of automation and low chemical consumption. Linear calibration graph in the range of 5-50 mg ClO3- L-1 was obtained, with detection limit of 1.4 mg ClO3- L-1. Relative standard deviation of 2.2% (30 mg ClO3- L-1, n=10 and sample throughput of about 20 h-1 were achieved. The system was applied to soil samples and validated by batch spectrophotometric and standard titrimetric methods.

  10. The determination of uranium(VI) by flow-injection analysis

    International Nuclear Information System (INIS)

    Jones, E.A.

    1985-01-01

    A method is described for the direct determination of uranium(VI) in waste waters and acid leach liquors by use of a flow-injection procedure and spectrophotometric measurement with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (bromo-PADAP). The interference effects of several commonly occurring elements were studied. The calibration curve is linear over concentrations of uranium(VI) from 0,5 to 20 mg/1, and the precision obtained on a synthetic leach liquor was 0,019 (relative standard deviation). The procedure is rapid and convenient, and up to 40 samples can be analysed in an hour

  11. [Determination of mercury in Boletus impolitus by flow injection-atomic absorption spectrometry].

    Science.gov (United States)

    Li, Tao; Wang, Yuan-Zhong

    2008-04-01

    Various test conditions and effect factors for the determination of mercury by flow injection-atomic absorption spectrometry were discussed, and a method for the determination of mercury in Boletus impolitus has been developed. The linear range for mercury is 0-60 microg x L(-1). The relative standard deviation is less than 3.0%, and the recovery is 96%-107%. This method is simple, rapid and has been applied to the determination of mercury in Boletus impolitus samples with satisfactory results.

  12. Stopped-flow injection method for determination of phosphate in soils and fertilisers

    Directory of Open Access Journals (Sweden)

    Jaroon Jakmunee

    2008-02-01

    Full Text Available A stopped-flow injection system for the determination of phosphate has been developed. It involves the phosphate-molybdate-ascorbic acid reactions in the molybdenum blue method. The system is controlled by a semi-automatic stopped-FI analyser with a light emitting diode (LED-colorimeter for monitoring the absorbance change relating to the concentration of a reaction product formed during the stopping period while the injected zone of a standard or sample is being in the flow cell. The slope of the FIAgram obtained is linearly proportional to the reaction rate, which depends on the phosphate concentration. Effects of concentration of reagents, viz. sodium molybdate, ascorbic acid and nitric acid, on the slope of the FIAgram were studied. The suitable concentration is 0.02 M, 0.25 %w/v and 0.15 M, respectively. A linear calibration graph in the range of 0.3-6.0 mg P L-1 was employed for the determination of phosphate in soil and fertiliser samples. The results obtained agree well with those from a standard spectrophotometric method.

  13. An automatic system for acidity determination based on sequential injection titration and the monosegmented flow approach.

    Science.gov (United States)

    Kozak, Joanna; Wójtowicz, Marzena; Gawenda, Nadzieja; Kościelniak, Paweł

    2011-06-15

    An automatic sequential injection system, combining monosegmented flow analysis, sequential injection analysis and sequential injection titration is proposed for acidity determination. The system enables controllable sample dilution and generation of standards of required concentration in a monosegmented sequential injection manner, sequential injection titration of the prepared solutions, data collecting, and handling. It has been tested on spectrophotometric determination of acetic, citric and phosphoric acids with sodium hydroxide used as a titrant and phenolphthalein or thymolphthalein (in the case of phosphoric acid determination) as indicators. Accuracy better than |4.4|% (RE) and repeatability better than 2.9% (RSD) have been obtained. It has been applied to the determination of total acidity in vinegars and various soft drinks. The system provides low sample (less than 0.3 mL) consumption. On average, analysis of a sample takes several minutes. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Spectrophotometric determination of phosphorus in iron alloys employing a flow injection system

    OpenAIRE

    Gervasio,Ana P. G.; Miranda,Carlos E. S.; Luca,Gilmara C.; Tumang,Cristiane A.; Campos,Luis F. P.; Reis,Boaventura F.

    2001-01-01

    A flow-injection procedure for spectrophotometric determination of phosphorus in electrolytic iron and iron alloys is proposed. The method is based on the ammonium molybdate reaction followed by stannous chloride reduction in acidic medium. In order to circumvent the severe interference caused by the major constituents such as Fe(III) and Cr(III), a mini-column packed with AG50W-X8 resin was coupled to the manifold. A sample throughput of 40 determinations per hour, a dynamical range from P 0...

  15. Flow injection spectrofluorimetric method for the determination of cadmium

    International Nuclear Information System (INIS)

    Bo Tang; Taixing Yue; Lili Zhang; Junsen Wu; Zhenzhen Chen

    2004-01-01

    A novel fluorescent reagent, o-vanillin furoylhydrazone (OVFH), was synthesized, and its infrared spectrum, elemental analysis and dissociation constant are reported. The reaction between Cd 2+ and OVFH produces an intensely fluorescent complex in ethanol-water medium of pH 10.00, and this finding has led to a simple, rapid, and sensitive flow injection (FI) spectrofluorimetric method for on-line determination of Cd 2+ . Under the optimum experimental conditions, the fluorescent complex had excitation and emission maxima at 393 and 494 nm, respectively. The linear range is from 0.025 to 8.0 μg mL -1 of Cd 2+ , the detection limit is 7.6 μg L -1 and the maximum sampling rate is 80 h -1 . The effect of interferences was studied. The method was successfully applied to the determination of cadmium in environmental samples. (author)

  16. Minicolumn field preconcentration and flow-injection flame atomic absorption spectrometric determination of cadmium in seawater

    International Nuclear Information System (INIS)

    Yebra-Biurrun, M.C.; Moreno-Cid, A.; Puig, L.

    2004-01-01

    A simple method for the continuous field preconcentration of trace dissolved cadmium in seawater samples has been developed based on the minicolumn field sampling technique. For this purpose, minicolumns containing Chelite P (aminomethylphosphonic groups) were connected to a field flow preconcentration system (FFPS). Once in the laboratory, these minicolumns are sequentially inserted into a flow-injection system for on-line cadmium elution and detection by flame atomic absorption spectrometry. Factorial designs have been used to optimise the FFPS and the flow-injection elution process. Six experimental variables were optimised: sample pH, sample flow-rate, eluent concentration, eluent volume, eluent flow-rate and minicolumn diameter. The detection limit (3F) of the procedure was 2.7 ng l -1 for a sample volume of 300 ml. The precision (expressed as relative standard deviation) for 11 independent determinations was 0.5-9.4% for cadmium solutions of 10-300 ng l -1 . Analysis of certified reference materials (SLEW-3 and NASS-5) showed good agreement with the certified values. This procedure has been successfully applied to the determination of cadmium in seawater samples from Galicia (Spain)

  17. Development of an automated flow injection analysis system for determination of phosphate in nutrient solutions.

    Science.gov (United States)

    Karadağ, Sevinç; Görüşük, Emine M; Çetinkaya, Ebru; Deveci, Seda; Dönmez, Koray B; Uncuoğlu, Emre; Doğu, Mustafa

    2018-01-25

    A fully automated flow injection analysis (FIA) system was developed for determination of phosphate ion in nutrient solutions. This newly developed FIA system is a portable, rapid and sensitive measuring instrument that allows on-line analysis and monitoring of phosphate ion concentration in nutrient solutions. The molybdenum blue method, which is widely used in FIA phosphate analysis, was adapted to the developed FIA system. The method is based on the formation of ammonium Mo(VI) ion by reaction of ammonium molybdate with the phosphate ion present in the medium. The Mo(VI) ion then reacts with ascorbic acid and is reduced to the spectrometrically measurable Mo(V) ion. New software specific for flow analysis was developed in the LabVIEW development environment to control all the components of the FIA system. The important factors affecting the analytical signal were identified as reagent flow rate, injection volume and post-injection flow path length, and they were optimized using Box-Behnken experimental design and response surface methodology. The optimum point for the maximum analytical signal was calculated as 0.50 mL min -1 reagent flow rate, 100 µL sample injection volume and 60 cm post-injection flow path length. The proposed FIA system had a sampling frequency of 100 samples per hour over a linear working range of 3-100 mg L -1 (R 2  = 0.9995). The relative standard deviation (RSD) was 1.09% and the limit of detection (LOD) was 0.34 mg L -1 . Various nutrient solutions from a tomato-growing hydroponic greenhouse were analyzed with the developed FIA system and the results were found to be in good agreement with vanadomolybdate chemical method findings. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  18. Indirect flow injection determination of N-acetyl-L-cysteine using cerium(IV) and ferroin

    International Nuclear Information System (INIS)

    Vieira, Heberth Juliano; Fatibello-Filho, Orlando

    2005-01-01

    An indirect flow injection spectrophotometric procedure is proposed for the determination of N-acetyl-L-cysteine in pharmaceutical formulations. In this system, ferroin ([Fe(II)-(fen) 2 ] 2+ ) in excess, with a strong absorption at 500 nm, is oxidized by cerium(IV) yielding cerium(III) and [Fe(III)-(fen) 2 ] 3+ (colorless), thus producing a baseline. When N-acetyl-L-cysteine solution is introduced into the flow injection system, it reacts with cerium(IV) increasing the analytical signal in proportion to the drug concentration. Under optimal experimental conditions, the linearity of the analytical curve for N-acetyl-L-cysteine ranged from 6.5x10 -6 to 1.3x10 -4 mol L -1 . The detection limit was 5.0x10 -6 mol L -1 and recoveries between 98.0 and 106% were obtained. The sampling frequency was 60 determinations per hour and the RSD was smaller than 1.4% for 2.2x10 -5 mol L -1 N-acetyl-L-cysteine. (author)

  19. Determination of mercury by multisyringe flow injection system with cold-vapor atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Leal, L.O.; Elsholz, O.; Forteza, R.; Cerda, V.

    2006-01-01

    A new software-controlled time-based multisyringe flow injection system for mercury determination by cold-vapor atomic absorption spectrometry is proposed. Precise known volumes of sample, reducing agent (1.1% SnCl 2 in 3% HCl) and carrier (3% HCl) are dispensed into a gas-liquid separation cell with a multisyringe burette coupled with one three-way solenoid valve. An argon flow delivers the reduced mercury to the spectrometer. The optimization of the system was carried out testing reaction coils and gas-liquid separators of different design as well as changing parameters, such as sample and reagents volumes, reagent concentrations and carrier gas flow rate, among others. The analytical curves were obtained within the range 50-5000 ng L -1 . The detection limit (3σ b /S) achieved is 5 ng L -1 . The relative standard deviation (R.S.D.) was 1.4%, evaluated from 16 successive injections of 250 ng L -1 Hg standard solution. The injection and sample throughput per hour were 44 and 11, respectively. This technique was validated by means of solid and water reference materials with good agreement with the certified values and was successfully applied to fish samples

  20. Determination of gallic acid with rhodanine by reverse flow injection analysis using simplex optimization.

    Science.gov (United States)

    Phakthong, Wilaiwan; Liawruangrath, Boonsom; Liawruangrath, Saisunee

    2014-12-01

    A reversed flow injection (rFI) system was designed and constructed for gallic acid determination. Gallic acid was determined based on the formation of chromogen between gallic acid and rhodanine, resulting in a colored product with a λmax at 520 nm. The optimum conditions for determining gallic acid were also investigated. Optimizations of the experimental conditions were carried out based on the so-call univariate method. The conditions obtained were 0.6% (w/v) rhodanine, 70% (v/v) ethanol, 0.9 mol L(-1) NaOH, 2.0 mL min(-1) flow rate, 75 μL injection loop and 600 cm mixing tubing length, respectively. Comparative optimizations of the experimental conditions were also carried out by multivariate or simplex optimization method. The conditions obtained were 1.2% (w/v) rhodanine, 70% (v/v) ethanol, 1.2 mol L(-1) NaOH, flow rate 2.5 mL min(-1), 75 μL injection loop and 600 cm mixing tubing length, respectively. It was found that the optimum conditions obtained by the former optimization method were mostly similar to those obtained by the latter method. The linear relationship between peak height and the concentration of gallic acid was obtained over the range of 0.1-35.0 mg L(-1) with the detection limit 0.081 mg L(-1). The relative standard deviations were found to be in the ranges 0.46-1.96% for 1, 10, 30 mg L(-1) of gallic acid (n=11). The method has the advantages of simplicity extremely high selectivity and high precision. The proposed method was successfully applied to the determination of gallic acid in longan samples without interferent effects from other common phenolic compounds that might be present in the longan samples collected in northern Thailand. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Determination of uranium (IV) in cloride solutions of enrichment columns by spectrometry with flow injection

    International Nuclear Information System (INIS)

    Bastos, M.B.R.

    1988-01-01

    The utilization of Flow Injection Analysis for the U (IV) spectrophotometric determination in chloride solutions is described. The method has been shown reproducible in the range of concentrations and conditions employed with a standard deviation of about 0,3. (C.G.C.) [pt

  2. Dual-phase gas-permeation flow-injection thermometric analysis for the determination of carbon dioxide.

    Science.gov (United States)

    Liu, S J; Tubino, M

    1998-11-01

    A flow-injection configuration based on a dual-phase gas-permeation system from a liquid donor to a gas acceptor stream with a thermistor flow-through detector is proposed for the direct analysis of the gas in the acceptor. This system was applied for the determination of carbon dioxide (in the form of carbonate) using the following chemical reaction: CO(2)(g)+2NH(3)(g)+H(2)O(g)=(NH(4))(2)CO(3)(s), with a linear response from 1x10(-3) to 50x10(-3) mol l(-1) of CO(3)(2-). Carbon dioxide was produced in the liquid donor and permeated into the gaseous acceptor stream of air/water vapor. The detection limit is 1x10(-3) mol l(-1) of carbonate, and a sampling frequency of 60 h(-1) is achieved with a relative standard deviation of 4.1% for replicate injections. The dual-phase gas-permeation flow-injection manifold, along with the membrane and phase separations, as well as the chemical reaction, provides enhanced selectivity when compared with the system employing a liquid acceptor stream, as serious interferents in this system, for instance, acetate and formate, among others, do not interfere in the proposed system.

  3. Rapid determination of 99Tc in environmental samples by high resolution ICP-MS coupled with on-line flow injection system

    International Nuclear Information System (INIS)

    Kim, C.K.; Kim, C.S.; Rho, B.H.; Lee, J.I.

    2002-01-01

    High resolution inductively coupled plasma mass spectrometry coupled with an on-line flow injection system (FI-HR-ICP-MS) was applied to determine the ultra-trace level 99 Tc in soil. The flow injection system (PrepLab TM ) was composed of two TEVA-Spec R resins, reduced remarkably the sample amounts and the analysis time, compared to the conventional analytical methods. In the flow injection system, Mo and Ru were sufficiently eliminated by using the flow injection system, with the decontamination factors of 1.6 x 10 4 and 9.9 x 10 5 , respectively. With the present method, it was possible to determine ultra-low level of 99 Tc in 3∼6 soil at 3-5 hours of analysis time per sample. The relative standard deviation for each sample was less than 4%. The detection limits for 99 Tc was 85 fg x ml -1 (0.05 mBq x ml -1 ), which was calculated from the three times standard deviation of the count rate of the blank. (author)

  4. A novel stopped flow injection-amperometric procedure for the determination of chlorate.

    Science.gov (United States)

    Tue-Ngeun, Orawan; Jakmunee, Jaroon; Grudpan, Kate

    2005-12-15

    A novel stopped flow injection-amperometric (sFI-Amp) procedure for determination of chlorate has been developed. The reaction of chlorate with excess potassium iodide and hydrochloric acid, forming iodine/triiodide that is further electrochemically reduced at a glassy carbon electrode at +200mV versus Ag/AgCl electrode is employed. In order to increase sensitivity without using of too high acid concentration, promoting of the reaction by increasing reaction time and temperature can be carried out. This can be done without increase of dispersion of the product zone by stopping the flow while the injected zone is being in a mixing coil which is immersed in a water bath of 55+/-0.5 degrees C. In a closed system of FIA, a side reaction of oxygen with iodide is also minimized. Under a set of conditions, linear calibration graphs were in the ranges of 1.2x10(-6)-6.0x10(-5)moll(-1)and 6.0x10(-5)-6.0x10(-4)moll(-1). A sample throughput of 25h(-1) was accomplished. Relative standard deviation was 2% (n=21, 1.2x10(-4)moll(-1) chlorate). The proposed sFI-Amp procedure was successfully applied to the determination of chlorate in soil samples from longan plantation area.

  5. Flow injection analysis simulations and diffusion coefficient determination by stochastic and deterministic optimization methods.

    Science.gov (United States)

    Kucza, Witold

    2013-07-25

    Stochastic and deterministic simulations of dispersion in cylindrical channels on the Poiseuille flow have been presented. The random walk (stochastic) and the uniform dispersion (deterministic) models have been used for computations of flow injection analysis responses. These methods coupled with the genetic algorithm and the Levenberg-Marquardt optimization methods, respectively, have been applied for determination of diffusion coefficients. The diffusion coefficients of fluorescein sodium, potassium hexacyanoferrate and potassium dichromate have been determined by means of the presented methods and FIA responses that are available in literature. The best-fit results agree with each other and with experimental data thus validating both presented approaches. Copyright © 2013 The Author. Published by Elsevier B.V. All rights reserved.

  6. Development of a flow method for the determination of phosphate in estuarine and freshwaters-Comparison of flow cells in spectrophotometric sequential injection analysis

    International Nuclear Information System (INIS)

    Mesquita, Raquel B.R.; Ferreira, M. Teresa S.O.B.; Toth, Ildiko V.; Bordalo, Adriano A.; McKelvie, Ian D.; Rangel, Antonio O.S.S.

    2011-01-01

    Highlights: → Sequential injection determination of phosphate in estuarine and freshwaters. → Alternative spectrophotometric flow cells are compared. → Minimization of schlieren effect was assessed. → Proposed method can cope with wide salinity ranges. → Multi-reflective cell shows clear advantages. - Abstract: A sequential injection system with dual analytical line was developed and applied in the comparison of two different detection systems viz; a conventional spectrophotometer with a commercial flow cell, and a multi-reflective flow cell coupled with a photometric detector under the same experimental conditions. The study was based on the spectrophotometric determination of phosphate using the molybdenum-blue chemistry. The two alternative flow cells were compared in terms of their response to variation of sample salinity, susceptibility to interferences and to refractive index changes. The developed method was applied to the determination of phosphate in natural waters (estuarine, river, well and ground waters). The achieved detection limit (0.007 μM PO 4 3- ) is consistent with the requirement of the target water samples, and a wide quantification range (0.024-9.5 μM) was achieved using both detection systems.

  7. Development of a flow method for the determination of phosphate in estuarine and freshwaters-Comparison of flow cells in spectrophotometric sequential injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Raquel B.R. [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, R. Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Laboratory of Hydrobiology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Institute of Marine Research (CIIMAR), Universidade do Porto, Lg. Abel Salazar 2, 4099-003 Porto (Portugal); Ferreira, M. Teresa S.O.B. [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, R. Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Toth, Ildiko V. [REQUIMTE, Departamento de Quimica, Faculdade de Farmacia, Universidade de Porto, Rua Anibal Cunha, 164, 4050-047 Porto (Portugal); Bordalo, Adriano A. [Laboratory of Hydrobiology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Institute of Marine Research (CIIMAR), Universidade do Porto, Lg. Abel Salazar 2, 4099-003 Porto (Portugal); McKelvie, Ian D. [School of Chemistry, University of Melbourne, Victoria 3010 (Australia); Rangel, Antonio O.S.S., E-mail: aorangel@esb.ucp.pt [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, R. Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal)

    2011-09-02

    Highlights: {yields} Sequential injection determination of phosphate in estuarine and freshwaters. {yields} Alternative spectrophotometric flow cells are compared. {yields} Minimization of schlieren effect was assessed. {yields} Proposed method can cope with wide salinity ranges. {yields} Multi-reflective cell shows clear advantages. - Abstract: A sequential injection system with dual analytical line was developed and applied in the comparison of two different detection systems viz; a conventional spectrophotometer with a commercial flow cell, and a multi-reflective flow cell coupled with a photometric detector under the same experimental conditions. The study was based on the spectrophotometric determination of phosphate using the molybdenum-blue chemistry. The two alternative flow cells were compared in terms of their response to variation of sample salinity, susceptibility to interferences and to refractive index changes. The developed method was applied to the determination of phosphate in natural waters (estuarine, river, well and ground waters). The achieved detection limit (0.007 {mu}M PO{sub 4}{sup 3-}) is consistent with the requirement of the target water samples, and a wide quantification range (0.024-9.5 {mu}M) was achieved using both detection systems.

  8. Micelle-mediated methodology for the preconcentration of uranium prior to its determination by flow injection

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Laespada, M E; Perez Pavon, J L; Moreno Cordero, B [Univ. de Salamanca (Spain). Dept. de Quimica Analitica, Nutricion y Bromatologia

    1993-02-01

    Cloud point extraction has been used for the preconcentration of uranium, prior to its determination by flow injection. The non-ionic surfactant employed was Triton X-114 and the reagent chosen to form a hydrophobic chelate of uranium was 1-(2-pyridylazo)-2-naphthol. The optimum conditions for the preconcentration and determination of uranium have been studied. This methodology has been applied to the determination of trace amounts of uranium in tap and river waters from Salamanca. (Author).

  9. Determination of Optimal Flow Paths for Safety Injection According to Accident Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Kwae Hwan; Kim, Ju Hyun; Kim, Dong Yeong; Na, Man Gyun [Chosun Univ., Gwangju (Korea, Republic of); Hur, Seop; Kim, Changhwoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    In case severe accidents happen, major safety parameters of nuclear reactors are rapidly changed. Therefore, operators are unable to respond appropriately. This situation causes the human error of operators that led to serious accidents at Chernobyl. In this study, we aimed to develop an algorithm that can be used to select the optimal flow path for cold shutdown in serious accidents, and to recover an NPP quickly and efficiently from the severe accidents. In order to select the optimal flow path, we applied a Dijkstra algorithm. The Dijkstra algorithm is used to find the path of minimum total length between two given nodes and needs a weight (or length) matrix. In this study, the weight between nodes was calculated from frictional and minor losses inside pipes. That is, the optimal flow path is found so that the pressure drop between a starting node (water source) and a destination node (position that cooling water is injected) is minimized. In case a severe accident has happened, if we inject cooling water through the optimized flow path, then the nuclear reactor will be safely and effectively returned into the cold shutdown state. In this study, we have analyzed the optimal flow paths for safety injection as a preliminary study for developing an accident recovery system. After analyzing the optimal flow path using the Dijkstra algorithm, and the optimal flow paths were selected by calculating the head loss according to path conditions.

  10. Determination of uranium in organic phase by flow injection spectrophotometric analysis

    International Nuclear Information System (INIS)

    Yu Yiyun

    1998-01-01

    Based on the use of merging zone circuit and simulating a series of standard solution of uranium in organic phase, uranium in unknown organic phase sample was determined by flow injection spectrophotometry. A linear calibration graph was obtained with correlation coefficient of 0.999 for uranium concentration in organic phase over 10∼200 mg/L. Isopropyl alcohol was used as carrier solution. Mixing colour solution contains isopropyl alcohol, triethanolamine, masking reagent and Br-PADAP. The relative standard deviation of the method was better than +-5%. Determination of each sample can be completed in one minute. The method characteristic is: (1) using merging zone and simulating standard solution of uranium in organic phase, the method is sensitive and reliable; (2) even if the determined solution was in turbid condition, it can be quantitatively determined; (3) by means of solution replace technique, the tube of peristaltic pump can be used over a long period of time

  11. Determination of pH by flow-injection analysis and by fiber-optrode analysis

    International Nuclear Information System (INIS)

    Pia, S.H.; Waltman, D.P.; Hillman, D.C.

    1988-07-01

    Two new procedures for measuring pH were developed. The first measures pH colorimetrically using a proprietary indicator-dye mixture in a flow injection analysis (FIA) procedure. The second measures pH using a fiber-optic chemical sensor (FOCS) specifically developed for pH determinations. The FOCS method measures pH by monitoring the fluorescence of a fluorescein derivative bonded to the distal end of a fiber-optic cable called an optrade. The FIA method currently has a precision and accuracy of about + or - 0.2 pH units and can measure 100 samples/hour. The FOCS method has a precision of + or - 0.05-0.20 pH units and an accuracy of + or - 0.1 to 0.6 pH units. About 10 to 60 samples can be analyzed. The characteristics of the FOCS Method will vary significantly with individual optrodes. The experimental results indicate that either flow-injection analysis or fiber optic chemical sensor analysis could form the basis for an alternative to electrometric measurement of pH in certain circumstances

  12. Flow-injection fluorimetric determination of menadione using on-line photo-reduction in micellar media

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

    2004-07-01

    A very sensitive fluorimetric method for the determination of menadione using a flow injection system is proposed. The method is based on the on-line reduction of menadione in dodecylsulphate micelles upon irradiation with UV light. The strong fluorescence of the reduced menadione in micellar medium is measured at 410 nm with excitation at 340 nm. The method shows a linear range between 2.42 and 245 ng ml{sup -1} and a limit of detection of 0.18 ng ml{sup -1}. The sample throughput was 90 injections per hour. The applicability of the assay was demonstrated by analysing this vitamin in commercial pharmaceutical preparations.

  13. Flow-injection fluorimetric determination of menadione using on-line photo-reduction in micellar media

    International Nuclear Information System (INIS)

    Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

    2004-01-01

    A very sensitive fluorimetric method for the determination of menadione using a flow injection system is proposed. The method is based on the on-line reduction of menadione in dodecylsulphate micelles upon irradiation with UV light. The strong fluorescence of the reduced menadione in micellar medium is measured at 410 nm with excitation at 340 nm. The method shows a linear range between 2.42 and 245 ng ml -1 and a limit of detection of 0.18 ng ml -1 . The sample throughput was 90 injections per hour. The applicability of the assay was demonstrated by analysing this vitamin in commercial pharmaceutical preparations

  14. Flow injection kinetic spectrofluorimetric determination of trace amounts of osmium

    Science.gov (United States)

    Tang, Bo; Zhang, Hui; Wang, Yan

    2005-07-01

    A flow injection (FI) kinetic spectrofluorimetric method is described for the determination of osmium(IV) and the possible mechanism of catalytic reaction is discussed. The method is based on the fluorescence enhancing reaction of o-vanillin furfuralhydrazone (OVFH) with potassium bromate, which is catalyzed by Os(IV) in water medium at pH 6.10 and 45 °C. OVFH is newly synthesized and its ionization, IR and elemental analysis are established. Under these experimental conditions, the oxidized product of OVFH has excitation and emission maxima at 337 and 490 nm, respectively. The linear range of this method is 0-600 ng ml -1 with the R.S.D. of 1.2%. The detection limit is 1.0 ng ml -1 of Os(IV). A high analysis rate of 24 samples h -1 is obtained by the FI method. The proposed method is applied successfully to determine Os(IV) in synthetic mixture and mineral samples, and the results are well consistent with the standard values.

  15. A volumetric flow sensor for automotive injection systems

    International Nuclear Information System (INIS)

    Schmid, U; Krötz, G; Schmitt-Landsiedel, D

    2008-01-01

    For further optimization of the automotive power train of diesel engines, advanced combustion processes require a highly flexible injection system, provided e.g. by the common rail (CR) injection technique. In the past, the feasibility to implement injection nozzle volumetric flow sensors based on the thermo-resistive measurement principle has been demonstrated up to injection pressures of 135 MPa (1350 bar). To evaluate the transient behaviour of the system-integrated flow sensors as well as an injection amount indicator used as a reference method, hydraulic simulations on the system level are performed for a CR injection system. Experimentally determined injection timings were found to be in good agreement with calculated values, especially for the novel sensing element which is directly implemented into the hydraulic system. For the first time pressure oscillations occurring after termination of the injection pulse, predicted theoretically, could be verified directly in the nozzle. In addition, the injected amount of fuel is monitored with the highest resolution ever reported in the literature

  16. A volumetric flow sensor for automotive injection systems

    Science.gov (United States)

    Schmid, U.; Krötz, G.; Schmitt-Landsiedel, D.

    2008-04-01

    For further optimization of the automotive power train of diesel engines, advanced combustion processes require a highly flexible injection system, provided e.g. by the common rail (CR) injection technique. In the past, the feasibility to implement injection nozzle volumetric flow sensors based on the thermo-resistive measurement principle has been demonstrated up to injection pressures of 135 MPa (1350 bar). To evaluate the transient behaviour of the system-integrated flow sensors as well as an injection amount indicator used as a reference method, hydraulic simulations on the system level are performed for a CR injection system. Experimentally determined injection timings were found to be in good agreement with calculated values, especially for the novel sensing element which is directly implemented into the hydraulic system. For the first time pressure oscillations occurring after termination of the injection pulse, predicted theoretically, could be verified directly in the nozzle. In addition, the injected amount of fuel is monitored with the highest resolution ever reported in the literature.

  17. Flow injection analysis in inductively coupled plasma spectrometry

    International Nuclear Information System (INIS)

    Rosias, Maria F.G.G.

    1995-10-01

    The main features of flow injection analysis (FIA) as contribution to the inductively coupled plasma (Icp) spectrometry are described. A systematic review of researches using the combined FIA-Icp and the benefits of this association are presented. Flow systems were proposed to perform on-line Icp solution management for multielemental determination by atomic emission spectrometry (Icp-AES) or mass spectrometry. The inclusion of on-line ion exchangers in flow systems for matrix separation and/or analyte preconcentration are presented. Together with those applications the new advent of instruments with facilities for multielement detection on flow injection signals are described. (author). 75 refs., 19 figs

  18. Flow-through solid-phase based optical sensor for the multisyringe flow injection trace determination of orthophosphate in waters with chemiluminescence detection

    International Nuclear Information System (INIS)

    Morais, Ines P.A.; Miro, Manuel; Manera, Matias; Estela, Jose Manuel; Cerda, Victor; Souto, M. Renata S.; Rangel, Antonio O.S.S.

    2004-01-01

    In this work, a novel flow-through solid-phase based chemiluminescence (CL) optical sensor is described for the trace determination of orthophosphate in waters exploiting the multisyringe flow injection analysis (MSFIA) concept with multicommutation. The proposed time-based injection flow system relies upon the in-line derivatisation of the analyte with ammonium molybdate in the presence of vanadate, and the transient immobilisation of the resulting heteropolyacid in a N-vinylpyrrolidone/divinylbenzene copolymer packed spiral shape flow-through cell located in front of the window of a photomultiplier tube. The simultaneous injection of well-defined slugs of luminol in alkaline medium and methanol solution towards the packed reactor is afterwards performed by proper switching of the solenoid valves. Then, the light emission from the luminol oxidation by the oxidant species retained onto the sorbent material is readily detected. At the same time, the generated molybdenum-blue compound is eluted by the minute amount of injected methanol, rendering the system prepared for a new measuring cycle. Therefore, the devised sensor enables the integration of the solid-phase CL reaction with elution and detection of the emitted light without the typical drawbacks of the molybdenum-blue based spectrophotometric procedures regarding the excess of molybdate anion, which causes high background signals due to its self-reduction. The noteworthy features of the developed CL-MSFIA system are the feasibility to accommodate reactions with different pH requirements and the ability to determine trace levels of orthophosphate in high silicate content samples (Si/P ratios up to 500). Under the optimised conditions, a dynamic linear range from 5 to 50 μg P l -1 for a 1.8 ml sample, repeatability better than 3.0% and a quantification limit of 4 μg P l -1 were attained. The flowing stream system handles 11 analysis h -1 and has been successfully applied to the determination of trace levels of

  19. Determination of tellurium in lead and lead alloy using flow injection-hydride generation atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Mesko, Marcia F.; Pozebon, Dirce; Flores, Erico M.M.; Dressler, Valderi L.

    2004-01-01

    A method based on flow injection-hydride generation atomic absorption spectrometry (FI-HG AAS) for the determination of trace amount of Te in lead and lead alloy is described. A flow injection system (FI) and related analytical parameters as well as Te determination and interference caused by Pb, Bi and Ag on Te were investigated. The Pb interference could be overcome by using a small sample volume, while the Bi interference could be overcome by thiourea. However, it was not possible to minimise the interference caused by Ag on Te. The optimised conditions for Te determination in the analysed samples were: 6 mol l -1 HCl as sample carrier solution, 0.75% (m/v) sodium tetrahydroborate as Te reductant, 40 μl of sample solution, and 200 ml min -1 Ar flow rate as carrier gas. The limit of quantification (LOQ) was 1.0 μg g -1 Te (using 250 mg of sample in 50 ml final solution), the limit of detection (LOD) was 2.5 μg l -1 and the relative standard deviation (RSD) was 6% for five consecutive measurements of sample solution. The standard addition calibration method was used. Relatively high sample throughput (ca. 45 sample runs can be performed in a working hour), reduced sample manipulation since matrix separation is not necessary, and minor waste generation are the main advantages of the proposed method for Te determination by FI-HG AAS

  20. Chemiluminescence determination of ultramicro DNA with a flow-injection method

    International Nuclear Information System (INIS)

    Chen Hui; Zhou Min; Jin Xiaoyong; Song Yumin; Zhang Ziyu; Ma Yongjun

    2002-01-01

    A high sensitive flow-injection chemiluminescence method for determination of calf thymus DNA and herring sperm DNA has been developed. The method is based on the chemiluminescence reaction of Rhodamine B-cerium(IV)-thermally denatured DNAs in sulfuric acid media. The proposed procedure allows quantitation of DNAs in the range 2.6x10 -5 to 0.26 μg ml -1 for calf thymus DNA and 5.0x10 -8 to 5.0x10 -5 μg ml -1 for herring sperm DNA with correlation coefficients 0.9998 and 0.9996 (both n=11), respectively. The detection limits (3σ) are 6.5x10 -6 μg ml -1 for calf thymus DNA and 4.3x10 -8 μg ml -1 for herring sperm DNA. The possible mechanism of chemiluminescence in the system is discussed

  1. Chemiluminescence determination of ultramicro DNA with a flow-injection method

    Energy Technology Data Exchange (ETDEWEB)

    Chen Hui; Zhou Min; Jin Xiaoyong; Song Yumin; Zhang Ziyu; Ma Yongjun

    2002-02-12

    A high sensitive flow-injection chemiluminescence method for determination of calf thymus DNA and herring sperm DNA has been developed. The method is based on the chemiluminescence reaction of Rhodamine B-cerium(IV)-thermally denatured DNAs in sulfuric acid media. The proposed procedure allows quantitation of DNAs in the range 2.6x10{sup -5} to 0.26 {mu}g ml{sup -1} for calf thymus DNA and 5.0x10{sup -8} to 5.0x10{sup -5} {mu}g ml{sup -1} for herring sperm DNA with correlation coefficients 0.9998 and 0.9996 (both n=11), respectively. The detection limits (3{sigma}) are 6.5x10{sup -6} {mu}g ml{sup -1} for calf thymus DNA and 4.3x10{sup -8} {mu}g ml{sup -1} for herring sperm DNA. The possible mechanism of chemiluminescence in the system is discussed.

  2. One-shot flow injection spectrophotometric simultaneous determination of copper, iron and zinc in patients' sera with newly developed multi-compartment flow cell

    International Nuclear Information System (INIS)

    Teshima, Norio; Gotoh, Shingo; Ida, Kazunori; Sakai, Tadao

    2006-01-01

    We propose here an affordable flow injection method for simultaneous spectrophotometric determination of copper, iron and zinc in patients' sera. The use of a newly designed multi-compartment flow cell allowed the simultaneous determination of the three metals with a single injection ('one-shot') and a double beam spectrophotometer. The chemistry relied on the reactions of these metals with 2-(5-nitro-2-pyridylazo)-5-[N-propyl-N-(3-sulfopropyl)amino]phenol (nitro-PAPS) to form corresponding colored complexes. At pH 3.8, only copper-nitro-PAPS complex was formed in the presence of pyrophosphate as a masking agent for iron, and then the copper and iron(II) complexes were formed in the presence of reductant (ascorbic acid) at the same pH, and finally all three metals reacted with nitro-PAPS at pH 8.6. The characteristics were introduced into the flow system to determine each metal selectively and sensitively. Under the optimum conditions, linear calibration curves for the three metals were obtained in the range of 0.01-1 mg L -1 with a sample throughput rate of 20 h -1 . The limits of detection (3σ) were 3.9 μg L -1 for copper, 4.1 μg L -1 for iron and 4.0 μg L -1 for zinc. The proposed method was applied to analysis of some patients' sera

  3. A novel approach for determination of free fatty acids in vegetable oils by a flow injection system with manual injection.

    Science.gov (United States)

    Ayyildiz, H Filiz; Kara, Huseyin; Sherazi, S T H

    2011-12-01

    A non-aqueous flow injection method for determining free fatty acid (FFA) content in corn and sunflower oil samples was developed. A single-line manifold system was built by modification of an HPLC for flow injection analysis (FIA). Without pre-treatment, oil samples were injected into a n-propanol solution containing KOH and phenolphthalein (PHP). The main parameters, such as flow rate of carrier phase, length, geometry, inner diameters of the coils and reagent concentration were all optimized. The proposed FIA method was validated for precision, accuracy, linear region, limit of detection (LOD) and limit of quantification (LOQ). The intra- and inter-day measurements of the precision of the method were found to be within the limits of acceptance criteria (RSD analyst. The linear concentration range was calculated as 0.09-1.50 and 0.07-1.40 FFA% for corn and sunflower oils, correspondingly. The LOD and LOQ were found to be 7.53 × 10(-4)-2.28 × 10(-3) oleic acid % and 7.11 × 10(-4)-2.23 × 10(-3) oleic acid % for corn and sunflower oils, respectively. The results were compared with those obtained by the AOCS (Ca-5a-40) method using statistical t and F tests, and a significant difference was not observed between the methods at a 95% confidence level. The proposed method is suitable for quality control of routine applications due to its simplicity, high sample throughput, and economy of solvents and sample, offering considerable promise as a low cost analytical system that needs minimum human intervention over long periods of time.

  4. Flow injection spectrophotometric determination of low concentrations of orthosphate in natural waters employing ion exchange resin

    International Nuclear Information System (INIS)

    Pessenda, L.C.R.

    1981-01-01

    A simple and fast method for the determination of low concentrations of orthophosphate in natural waters is described. Ion exchange is incorporated into a flow injection system by usina a resin column in the sample loop of a proportion injector. Effects of sample aspiration rate, sampling time, eluting agent concentration, pumping rate of the sample carrier stream and interfaces, were investigated both using 32 PO 3- 4 or 31 PO 3- 4 with columns coupled to a gerger-muller detector and incorporated in a flow system with molybdenum blue colorinetry. (M.A.C.) [pt

  5. Spectrophotometric determination of phosphorus in iron alloys employing a flow injection system

    Directory of Open Access Journals (Sweden)

    Gervasio Ana P. G.

    2001-01-01

    Full Text Available A flow-injection procedure for spectrophotometric determination of phosphorus in electrolytic iron and iron alloys is proposed. The method is based on the ammonium molybdate reaction followed by stannous chloride reduction in acidic medium. In order to circumvent the severe interference caused by the major constituents such as Fe(III and Cr(III, a mini-column packed with AG50W-X8 resin was coupled to the manifold. A sample throughput of 40 determinations per hour, a dynamical range from P 0.25 to 6.00 mg L-1, a reagent consumption of 25 mg ammonium molybdate and 2 mg stannous chloride per determination, and a relative standard deviation < 1% (n = 10 for a typical sample with 2.20 mg L-1 P were achieved. Three different types of samples were used to evaluate system performance. Accuracy was assessed by comparing the results with certified values and no significant difference at 95 % confidence level was observed.

  6. A rapid and accurate method for determining protein content in dairy products based on asynchronous-injection alternating merging zone flow-injection spectrophotometry.

    Science.gov (United States)

    Liang, Qin-Qin; Li, Yong-Sheng

    2013-12-01

    An accurate and rapid method and a system to determine protein content using asynchronous-injection alternating merging zone flow-injection spectrophotometry based on reaction between coomassie brilliant blue G250 (CBBG) and protein was established. Main merit of our approach is that it can avoid interferences of other nitric-compounds in samples, such as melamine and urea. Optimized conditions are as follows: Concentrations of CBBG, polyvinyl alcohol (PVA), NaCl and HCl are 150 mg/l, 30 mg/l, 0.1 mol/l and 1.0% (v/v), respectively; volumes of the sample and reagent are 150 μl and 30 μl, respectively; length of a reaction coil is 200 cm; total flow rate is 2.65 ml/min. The linear range of the method is 0.5-15 mg/l (BSA), its detection limit is 0.05 mg/l, relative standard deviation is less than 1.87% (n=11), and analytical speed is 60 samples per hour. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Modified and reverse radiometric flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Myint, U; Ba, H; Khin, M M; Aung, K; Thida, [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

    1994-06-01

    Determination of [sup 137]Cs and [sup 60]Co by using modified and reverse radiometric flow injection analysis is described. Two component RFIA was also realized using [sup 60]Co and [sup 137]Cs radionuclides. (author) 2 refs.; 5 figs.

  8. A novel automatic flow method with direct-injection photometric detector for determination of dissolved reactive phosphorus in wastewater and freshwater samples.

    Science.gov (United States)

    Koronkiewicz, Stanislawa; Trifescu, Mihaela; Smoczynski, Lech; Ratnaweera, Harsha; Kalinowski, Slawomir

    2018-02-12

    The novel automatic flow system, direct-injection detector (DID) integrated with multi-pumping flow system (MPFS), dedicated for the photometric determination of orthophosphates in wastewater and freshwater samples is for the first time described. All reagents and the sample were injected simultaneously, in counter-current into the reaction-detection chamber by the system of specially selected for this purpose solenoid micro-pumps. The micro-pumps provided good precision and accuracy of the injected volumes. For the determination of orthophosphates, the molybdenum blue method was employed. The developed method can be used to detect orthophosphate in the range 0.1-12 mg L -1 , with the repeatability (RSD) about 2.2% at 4 mg L -1 and a very high injection throughput of 120 injections h -1 . It was possible to achieve a very small consumption of reagents (10 μL of ammonium molybdate and 10 μL of ascorbic acid) and sample (20 μL). The volume of generated waste was only 440 μL per analysis. The method has been successfully applied, giving a good accuracy, to determination of orthophosphates in complex matrix samples: treated wastewater, lake water and reference sample of groundwater. The developed system is compact, small in both size and weight, requires 12 V in supply voltage, which are desirable for truly portable equipment used in routine analysis. The simplicity of the system should result in its greater long-time reliability comparing to other flow methods previously described.

  9. Determination of Nitrite and Nitrate in Natural Waters Using Flow Injection with Spectrophotometric Detection

    International Nuclear Information System (INIS)

    Yaqoob, M.; Nabi, A.

    2013-01-01

    A simple and sensitive flow injection spectrophotometric method is reported for the room temperature determination of nitrite and nitrate based on the Griess reaction and a copperised cadmium column for reduction of nitrate. Calibration graphs were linear over the range 2 - 1000 micro g N L /sup -1/ (R2 = 0.9997 and 0.9999, n = 9) with a limit of detection (3 s.d.) of 1.0 micro g N L and relative standard deviations (n = 10) of 0.9 and 1.2% for 50 micro g N L nitrite and nitrate respectively. The sample throughput was 50 h. The effect of reagent concentrations, physical parameters (flow rate, sample volume, reaction coil and copperised cadmium column length) and the potential interferences are reported. The effect of salinity on the blank and on the determination of nitrite and nitrate are also presented. The method was applied to natural waters (rainwater, freshwater and estuarine water) and the results for nitrite + nitrate (140 - 7310 micro g N L/sup -1/) were not significantly different (95% confidence interval) from results obtained using a segmented flow analyser reference method with spectrophotometric detection. (author)

  10. Sibutramine selective electrodes for batch and flow injection determinations in pharmaceutical preparations.

    Science.gov (United States)

    Zayed, S I M; Issa, Y M

    2010-01-01

    The construction and electrochemical response characteristics of two new polyvinyl chloride (PVC) membrane sensors for the determination of sibutramine hydrochloride were described. The sensors are based on the ion association complexes of sibutramine with sodium tetraphenylborate (NaTPB) or phosphotungstic acid (PTA) using dibutyl phthalate as plasticizing solvent. The sensors display a fast, stable response over the concentration range 3.84 x 10(-5)-1.00 x 10(-2) M sibutramine hydrochloride monohydrate (SibuCl), with cationic slopes of 57.7 +/- 0.57 and 59.7 +/- 1.79 mV concentration decade(-1) and detection limits of 8.91 x 10(-6) and 1.47 x 10(-5) M in case of sibutramine-tetraphenylborate (Sibu-TPB) and sibutramine-phosphotungstate ((Sibu)(3)-PT), respectively. The proposed sensors have been successfully applied for the determination of sibutramine hydrochloride in Regitrim capsules in batch and flow injection (FI) conditions.

  11. Direct microcomputer controlled determination of zinc in human serum by flow injection atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Simonsen, Kirsten Wiese; Nielsen, Bent; Jensen, Arne

    1986-01-01

    A procedure is described for the direct determination of zinc in human serum by fully automated, microcomputer controlled flow injection atomic absorption spectrometry (Fl-AAS). The Fl system is pumpless, using the negative pressure created by the nebuliser. It only consists of a three-way valve......, programmable from the microcomputer, to control the sample volume. No pre-treatment of the samples is necessary. The limit of detection is 0.14 mg l–1, and only small amounts of serum (

  12. Individual renal plasma flow determination in 2 minutes

    International Nuclear Information System (INIS)

    Schlegel, J.U.; Hamway, S.A.

    1976-01-01

    A method is described for determining effective renal plasma flow, using the renal counts 1 to 2 minutes after injection and applying background subtraction as a ratio to the total amount of radioactivity injected intravenously with appropriate correction for kidney depth. It appears that this simple approach for determination of effective renal plasma flow within a matter of 2 minutes is accurate and reliable, and should be useful for a number of applications when it is important to determine total and individual renal plasma flow. The approach is recommended as a screening procedure in lieu of the determination of blood urea nitrogen and serum creatinine, with the additional advantages of gross morphology and determination of individual renal plasma flow in an absolute as well as relative manner

  13. Development of flow injection method for indirect copper determination with amperometric detection in drinking water samples

    Directory of Open Access Journals (Sweden)

    Nikolić-Mandić Snežana

    2012-01-01

    Full Text Available A gas-diffusion flow injection method with amperometric detection for indirect copper determination on a silver electrode is developed. The flow through system is equipped with two injection valves and a gas-diffusion unit. In the first step, a signal of cyanide solution was recorded. In the following step a signal of cyanide in the presence of copper was measured. Interferences (Cd(II, Co(II, Ag(I, Ni(II, Fe(III, Hg(II and Zn(II were investigated and successfully removed. The calibration graph is linear in the range 1-90 μmol dm-3 of copper, correlation coefficient is 0.993, the regression equation is I = (0.0455±0.0015c + (0.4611±0.0671, I is relative signal decrease in μA and c is concentration in μmol dm-3. Relative standard deviation for six consecutive injections of 30 μmol dm-3 copper(II was 1.47 % and for 1 μmol dm-3 copper(II was 3.40 %. The detection limit, calculated as 3 s/m (where s is a standard deviation of nine measurement of a reagent blank and m is the slope of the calibration curve, was 0.32 μmol dm-3, which corresponds to 2.44 ng of copper(II (loop volume was 0.12 cm3. The method enables 60 analyses per hour and it was successfully applied on determination of copper in drinking water samples. [Acknowledgements. The authors acknowledge the grant from the Ministry of Education and Science of the Republic of Serbia, Project number 172051

  14. Flow injection spectrophotometry using natural reagent from Morinda citrifolia root for determination of aluminium in tea.

    Science.gov (United States)

    Tontrong, Sopa; Khonyoung, Supada; Jakmunee, Jaroon

    2012-05-01

    A flow injection (FI) spectrophotometric method with using natural reagent extracted from Morinda citrifolia root has been developed for determination of aluminium. The extract contained anthraquinone compounds which could react with Al(3+) to form reddish complexes which had maximum absorption wavelength at 499.0nm. The extract could be used as a reagent in FI system without further purification to obtain pure compound. A sensitive method for determination of aluminium in concentration range of 0.1-1.0mgL(-1), with detection limit of 0.05mgL(-1) was achieved. Relative standard deviations of 1.2% and 1.7% were obtained for the determination of 0.1 and 0.6mgL(-1) Al(3+) (n=11). Sample throughput of 35h(-1) was achieved with the consumption of 3mL each of carrier and reagent solutions per injection. The developed method was successfully applied to tea samples, validated by the FAAS standard method. The method is simple, fast, economical and could be classified as a greener analytical method. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Flow-Injection Amperometric Determination of Tacrine based on Ion Transfer across a Water–Plasticized Polymeric Membrane Interface

    Directory of Open Access Journals (Sweden)

    C. Rueda

    2007-07-01

    Full Text Available A flow-injection pulse amperometric method for determining tacrine, based onion transfer across a plasticized poly(vinyl chloride (PVC membrane, was developed. Afour-electrode potentiostat with ohmic drop compensation was used, while a flow-throughcell incorporated the four electrodes and the membrane, which containedtetrabutylammonium tetraphenylborate. The influence of the applied potential and of theflow-injection variables on the determination of tacrine was studied. In the selectedconditions, a linear relationship between peak height and tacrine concentration was foundup to 4x10-5M tacrine. The detection limit was 1x10-7M. Good repeatability was obtained.Some common ions and pharmaceutical excipients did not interfere.

  16. Sensitive flow-injection spectrophotometric analysis of bromopride

    Science.gov (United States)

    Lima, Liliane Spazzapam; Weinert, Patrícia Los; Pezza, Leonardo; Pezza, Helena Redigolo

    2014-12-01

    A flow injection spectrophotometric procedure employing merging zones is proposed for direct bromopride determination in pharmaceutical formulations and biological fluids. The proposed method is based on the reaction between bromopride and p-dimethylaminocinnamaldehyde (p-DAC) in acid medium, in the presence of sodium dodecyl sulfate (SDS), resulting in formation of a violet product (λmax = 565 nm). Experimental design methodologies were used to optimize the experimental conditions. The Beer-Lambert law was obeyed in a bromopride concentration range of 3.63 × 10-7 to 2.90 × 10-5 mol L-1, with a correlation coefficient (r) of 0.9999. The limits of detection and quantification were 1.07 × 10-7 and 3.57 × 10-7 mol L-1, respectively. The proposed method was successfully applied to the determination of bromopride in pharmaceuticals and human urine, and recoveries of the drug from these media were in the ranges 99.6-101.2% and 98.6-102.1%, respectively. This new flow injection procedure does not require any sample pretreatment steps.

  17. The impact of interpreted flow regimes during constant head injection tests on the estimated transmissivity from injection tests and difference flow logging

    Energy Technology Data Exchange (ETDEWEB)

    Hjerne, Calle; Ludvigsson, Jan-Erik; Harrstroem, Johan [Geosigma AB, Uppsala (Sweden)

    2013-04-15

    A large number of constant head injection tests were carried out in the site investigation at Forsmark using the Pipe String System, PSS3. During the original evaluation of the tests the dominating transient flow regimes during both the injection and recovery period were interpreted together with estimation of hydraulic parameters. The flow regimes represent different flow and boundary conditions during the tests. Different boreholes or borehole intervals may display different distributions of flow regimes. In some boreholes good agreement was obtained between the results of the injection tests and difference flow logging with Posiva flow log (PFL) but in other boreholes significant discrepancies were found. The main objective of this project is to study the correlation between transient flow regimes from the injection tests and other borehole features such as transmissivity, depth, geology, fracturing etc. Another subject studied is whether observed discrepancies between estimated transmissivity from difference flow logging and injection tests can be correlated to interpreted flow regimes. Finally, a detailed comparison between transient and stationary evaluation of transmissivity from the injection tests in relation to estimated transmissivity from PFL tests in corresponding sections is made. Results from previous injection tests in 5 m sections in boreholes KFM04, KFM08A and KFM10A were used. Only injection tests above the (test-specific) measurement limit regarding flow rate are included in the analyses. For all of these tests transient flow regimes were interpreted. In addition, results from difference flow logging in the corresponding 5 m test sections were used. Finally, geological data of fractures together with rock and fracture zone properties have been used in the correlations. Flow regimes interpreted from the injection period of the tests are generally used in the correlations but deviations between the interpreted flow regimes from the injection and

  18. Flow injection on-line dilution for multi-element determination in human urine with detection by inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald; Gammelgaard, Bente

    2001-01-01

    A simple flow injection on-line dilution procedure with detection by inductively coupled plasma mass spectrometry (ICP-MS) was developed for the determination of copper, zinc, arsenic, lead, selenium, nickel and molybdenum in human urine. Matrix effects were minimized by employing a dilution factor...

  19. Flow injection spectrophotometric determination of Fe(III) and V(v)

    International Nuclear Information System (INIS)

    Elrahman, Azza Mohamed

    2000-01-01

    Phenylflourone was synthesized with the objective of developing a method for determining Fe(III) and V(V) in the pressence of micelles using flow injectoin technique. Phenylflourone showed a wavelength of maximum absorption at 412 nm which was not affected by the presence of miccelles i.e. n-hexadodecylpyridinum bromide and sodium n-dodecylsulphate, but they have different effects on the absorbance of PHF. The example of PHF-Fe(III) and PHF-V(V) showed the wavelength of the maximum absorption at 4428 nm and 412 nm, respectively. Presence of micelles shifted the wavelength of the two complexes to a lower one. Generally the addition of micelles increased the absorbance of phenylflourone metal ions complexes except for PHF-V(V) with hexadodecylpyridinum bromide. With flow injection technique two approaches were practiced the use of micelle as a carrier or water as a carrier. Sodium n-dodecylsulphate increased the absorbance of the two complexes when it was used as a carrier or added to the metal ions using water as carrier. On the other hand, the use of n-hexadodecylpyridinum bromide as carrieer increased the absorbance of the complexes but it decreased the absorbance when it was used in conjunction with metal ions and water as a carrier. After establishing the optimum FI conditions for PHF-Fe(III) and PHF-V(V) complexes, the calibration curves were construction and produced semiliner response in the concentration range studied. Ti(IV) III, Mo(VI) showed a positive interference in PHF-Fe(III) and PHF-V(V) complexes, respectively.(Author)

  20. Flow injection determination of lead and cadmium in hair samples from workers exposed to welding fumes

    International Nuclear Information System (INIS)

    Cespon-Romero, R.M.; Yebra-Biurrun, M.C.

    2007-01-01

    A flow injection procedure involving continuous acid leaching for lead and cadmium determination in hair samples of persons in permanent contact with a polluted workplace environment by flame atomic absorption spectrometry is proposed. Variables such as sonication time, nature and concentration of the acid solution used as leaching solution, leaching temperature, flow-rate of the continuous manifold, leaching solution volume and hair particle size were simultaneously studied by applying a Plackett-Burman design approach. Results showed that nitric acid concentration (leaching solution), leaching temperature and sonication time were statistically significant variables (confidence interval of 95%). These last two variables were finally optimised by using a central composite design. The proposed procedure allowed the determination of cadmium and lead with limits of detection 0.1 and 1.0 μg g -1 , respectively. The accuracy of the developed procedure was evaluated by the analysis of a certified reference material (CRM 397, human hair, from the BCR). The proposed method was applied with satisfactory results to the determination of Cd and Pb in human hair samples of workers exposed to welding fumes

  1. Chemiluminescent determination of vanadium(IV) using a cinchomeronic hydrazide-H2O2 system and flow injection analysis

    International Nuclear Information System (INIS)

    Pradana Perez, J.A.; Alegria, J.S. Durand; Hernando, P. Fernandez; Sierra, A. Narros

    2005-01-01

    This paper proposes a new chemiluminescent flow injection analysis (FIA) method for the determination of vanadium(IV) ions in aqueous media. The method is based on the chemiluminescent reaction that occurs between cinchomeronic hydrazide (CH) and hydrogen peroxide in a strongly alkaline medium, in which vanadium(IV) acts as a catalyst. The chemical and physical variables involved in the flow injection system are optimised using a modified simplex method. Vanadium ions can be detected in the 0.08 and 1.00 μg mL -1 range; the detection limit for a signal-to-noise ratio of 3 is 0.08 μg mL -1 . Great variations in the quantum yield were observed when cobalt(II), chromium(III), copper(II) and/or nickel(II) were present in the reaction medium. The proposed method is selective and simple, and can be successfully used to analyse water samples without the need for separation or preconcentration processes

  2. Flow injection chemiluminescent determination of N-nitrosodimethylamine using photogenerated tris(2,2'-bipyridyl) ruthenium (III)

    International Nuclear Information System (INIS)

    Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

    2005-01-01

    A flow injection configuration was developed and evaluated for the chemiluminescent determination of N-nitrosodimethylamine. The method is based on the on-line cleavage of the N-NO bond of the nitrosamine by irradiation with ultraviolet light. The dimethylamine generated was subsequently reacted with tris(2,2'-bipyridyl) ruthenium (III), which was generated through the on-line photo-oxidation of tris(2,2'-bipyridyl) ruthenium (II) with peroxydisulfate. After selecting the best operating parameters, the emitted light showed a linear relationship with the concentration of N-nitrosodimethylamine between 1.5 and 148 ng ml -1 , with a detection limit of 0.29 ng ml -1 . The repeatability was 1.6% expressed as relative standard deviation (n = 10) and the reproducibility, studied on five consecutive days, was 3.2%. The sample throughput was 50 injections per hour. The method was applied to studying the recoveries of N-nitrosodimethylamine in water and different cured meat products

  3. New method for simultaneous determination of Fe(II) and Fe(III) in water using flow injection technique

    International Nuclear Information System (INIS)

    Kozak, J.; Gutowski, J.; Kozak, M.; Wieczorek, M.; Koscielniak, P.

    2010-01-01

    The method exploits the possibilities of flow injection gradient titration in a system of reversed flow with spectrophotometric detection. In the developed approach a small amount of titrant (EDTA) is injected into a stream of sample containing a mixture of indicators (sulfosalicylic acid and 1,10-phenanthroline). In acid environment sulfosalicylic acid forms a complex with Fe(III), whereas 1,10-phenanthroline forms a complex with Fe(II). Measurements are performed at wavelength λ = 530 nm when radiation is absorbed by both complexes. After injection EDTA replaces sulfosalicylic acid and forms with Fe(III) more stable colourless complex. As a result, a characteristic 'cut off' peak is registered with a width corresponding to the Fe(III) concentration and with a height corresponding to the Fe(II) concentration. Calibration was performed by titration of four two-component standard solutions of the Fe(II)/Fe(III) concentrations established in accordance with 2 2 factorial plan. The method was tested with the use of synthetic samples and then it was applied to the analysis of water samples taken from artesian wells. Under optimized experimental conditions Fe(II) and Fe(III) were determined with precision less than 0.8 and 2.5% (RSD) and accuracy less than 3.2 and 5.1% (relative error) within the concentration ranges of 0.1-3.0 and 0.9-3.5 mg L -1 of both analytes, respectively.

  4. Development of flow injection analysis technique for uranium estimation

    International Nuclear Information System (INIS)

    Paranjape, A.H.; Pandit, S.S.; Shinde, S.S.; Ramanujam, A.; Dhumwad, R.K.

    1991-01-01

    Flow injection analysis is increasingly used as a process control analytical technique in many industries. It involves injection of the sample at a constant rate into a steady flowing stream of reagent and passing this mixture through a suitable detector. This paper describes the development of such a system for the analysis of uranium (VI) and (IV) and its gross gamma activity. It is amenable for on-line or automated off-line monitoring of uranium and its activity in process streams. The sample injection port is suitable for automated injection of radioactive samples. The performance of the system has been tested for the colorimetric response of U(VI) samples at 410 nm in the range of 35 to 360mg/ml in nitric acid medium using Metrohm 662 Photometer and a recorder as detector assembly. The precision of the method is found to be better than +/- 0.5%. This technique with certain modifications is used for the analysis of U(VI) in the range 0.1-3mg/ailq. by alcoholic thiocynate procedure within +/- 1.5% precision. Similarly the precision for the determination of U(IV) in the range 15-120 mg at 650 nm is found to be better than 5%. With NaI well-type detector in the flow line, the gross gamma counting of the solution under flow is found to be within a precision of +/- 5%. (author). 4 refs., 2 figs., 1 tab

  5. Flow Injection/Sequential Injection Analysis Systems: Potential Use as Tools for Rapid Liver Diseases Biomarker Study

    Directory of Open Access Journals (Sweden)

    Supaporn Kradtap Hartwell

    2012-01-01

    Full Text Available Flow injection/sequential injection analysis (FIA/SIA systems are suitable for carrying out automatic wet chemical/biochemical reactions with reduced volume and time consumption. Various parts of the system such as pump, valve, and reactor may be built or adapted from available materials. Therefore the systems can be at lower cost as compared to other instrumentation-based analysis systems. Their applications for determination of biomarkers for liver diseases have been demonstrated in various formats of operation but only a few and limited types of biomarkers have been used as model analytes. This paper summarizes these applications for different types of reactions as a guide for using flow-based systems in more biomarker and/or multibiomarker studies.

  6. Application of a field flow preconcentration system with a minicolumn packed with amberlite XAD-4/1-(2-pyridylazo)-2-naphtol and a flow injection-flame atomic adsorption spectrometric system for lead determination in sea water

    International Nuclear Information System (INIS)

    Carmen Yebra, M. del; Rodriguez, L.; Puig, L.; Moreno-Cid, A.

    2002-01-01

    A field flow preconcentration technique involving a minicolumn containing Amberlite XAD-4 impregnated with the complexing agent 1-(2-pyridylazo)-2-naphthol was used to preconcentrate lead from seawater. Elution of retained lead on the minicolumns was performed by a flow-injection-flame atomic absorption spectrometric system. Factorial designs have been used to optimize the field flow preconcentration system and the flow injection elution process. Factors such as sample pH, sample flow-rate, eluent concentration and volume (hydrochloric acid), elution flow-rate and minicolumn diameter were considered. The results suggest that the sample flow-rate and the eluent volume are statistically significant factors. The detection limit (3σ) of the procedure was 5 ng/L for a sample volume of 1000 ml. The precision (expressed as relative standard deviation) for eleven independent determinations reached values of 4.0-3.1 % in lead solutions of 50-200 ng/L. This procedure has been successfully applied to the determination of lead in seawater from Galicia (Spain). (author)

  7. Charge Injection and Current Flow in Organic Light Emitting Diodes

    Science.gov (United States)

    Smith, D. L.; Davids, P. S.; Heller, C. M.; Crone, B. K.; Campbell, I. H.; Barashkov, N. N.; Ferraris, J. P.

    1997-03-01

    We present a comparison between device model calculations and current-voltage measurements for a series of organic LED structures. The Schottky energy barrier of an injecting contact is systematically varied by changing the metal used to form that contact. The current-voltage characteristics of the structures are described using a device model that considers charge injection, transport and space charge effects in the low mobility organic material. Charge injection into the organic material is controlled by the Schottky energy barrier of the metal/organic contact. For Schottky energy barriers greater than about 0.4 eV injection into the organic material is the principal limitation to current flow. In this regime the net injected charge density is relatively small, the electric field in the structure is nearly uniform, and space charge effects are not important. For smaller energy barriers relatively large charge densities are injected into the organic material and space charge effects become the dominant limit to current flow. The measured current-voltage characteristics are quantitatively described by the device model using Schottky barrier values independently determined by internal photoemission and electroabsorption measurements.

  8. Batch and flow-injection methods for the spectrophotometric determination of olanzapine

    Energy Technology Data Exchange (ETDEWEB)

    Jasinska, A.; Nalewajko, E

    2004-04-22

    An indirect batch spectrophotometric and direct flow-injection (FI) visible spectrophotometric methods have been developed for the determination of the novel anti-psychotic drug olanzapine (OLA). The batch method is based on the oxidation of olanzapine by a known excess of potassium hexacyanoferrate(III) in the presence of the mixture of sulphuric and phosphoric acids (1:1 (v/v)). The absorbance of unreacted oxidant is measured at 425 nm. The absorbance decreases linearly with increasing concentration of the assayed drug. The FI method with detection at 540 nm is based on the direct oxidation of olanzapine one of two oxidants, cerium(IV) sulphate or potassium hexacyanoferrate(III) in acidic medium. The calibration graph were linear over the range of 2.5-40 {mu}g ml{sup -1} in the batch method and 0.05-300 and 0.5-250 {mu}g ml{sup -1} in the FI methods, used cerium (IV) sulphate and potassium hexacyanoferrate (III) respectively. Both FI methods gave similar results in terms of precision and accuracy. The relative standard deviation (R.S.D.), was <1%. The accuracy, obtained from recovery experiments, was 97.9-99.4%. The batch method gave slightly higher R.S.D. values (up to 2.3%) and lower values of accuracy (the recovery was between 96.5 and 96.6%). The methods developed were applied to the determination of olanzapine in a pharmaceutical product.

  9. A Simple and Rapid Flow-Injection Chemiluminescence Method for the Determination of Noscapine with Ru(phen)32+-Ce(4) System

    International Nuclear Information System (INIS)

    Rezaei, B.; Mokhtari, A.; Khayamian, T.

    2007-01-01

    A new flow injection chemiluminescence (CL) system was used for the determination of noscapine. This technique is based on the reduction effect of noscapine on the Ru(phen) 3 3+ , which is produced by reaction between Ru(phen) 3 2+ and acidic Ce(4) solutions, and this rapid reduction produces strong CL. Calibration plots were linear over the range of 3.0x10 -7 -2.0x10 -6 mol L -1 and 2.0x10 -6 -2.0x10 -4 mol L -1 . The CL intensity was so high, that it is able to produce a detection limit of 6.6x10 -8 M noscapine (3σ). The relative standard deviation of 2.0x10 -6 M noscapine was 1.0% (n=10). The proposed method was successfully applied for the flow injection determination of noscapine in cough and Tonin syrup samples. The results of real sample analyses show good recovery percentages (97.3-102.4%). The minimum sampling rate was 100 samples per hour

  10. The Co-axial Flow of Injectable Solid Hydrogels with Encapsulated Cells

    Science.gov (United States)

    Stewart, Brandon; Pochan, Darrin; Sathaye, Sameer

    2013-03-01

    Hydrogels are quickly becoming an important biomaterial that can be used for the safe, localized injection of cancer drugs, the injection of stem cells into areas of interest or other biological applications. Our peptides can be self-assembled in a syringe where they form a gel, sheared by injection and, once in the body, immediately reform a localized pocket of stiff gel. My project has been designed around looking at the possibility of having a co-axial strand, in which one gel can surround another. This co-axial flow can be used to change the physical properties of our gel during injection, such as stiffening our gel using hyaluronic acid or encapsulating cells in the gel and surrounding the gel with growth medium or other biological factors. Rheology on hyaluron stiffened gels and cells encapsulated in gels was performed for comparison to the results from co-axial flow. Confocal microscopy was used to examine the coaxial gels after flow and to determine how the co-axial nature of the gels is affected by the concentration of peptide.

  11. Determination of trace elements in seawater by air-flow injection/ICP-MS with chelating resin preconcentration

    International Nuclear Information System (INIS)

    Lee, Kyue-Hyung; Ohshima, Mitsuko; Motomizu, Shoji

    2002-01-01

    Multielement determination of major to trace metals in a deep seawater malt was accomplished by inductively coupled plasma-mass spectrometry (ICP-MS) together with inductively coupled plasma-atomic emission spectrometry (ICP-AES). Major elements, such as Na, K, Mg, and Ca, were measured by ICP-AES and normal continuos nebulization ICP-MS after sample dilution by 10 3 -10 6 fold. Fifteen trace elements in the concentrated metal solutions pretreated with cation-exchange resin or chelating resin could be simultaneously determined by air-flow injection/ICP-mass spectrometry (AFI/ICP-MS). Since the injection volume for AFI/ICP-MS was 25 μl, final samples volumes less than 500 μl were enough for several replicate measurements. Three different preconcentration methods assisted with AFI/ICP-MS were examined and could be successfully applied to a deep seawater malt. The analytical results of rate earth elements (REEs) and Co, Ni, Cu, Zn, Cd, and Pb obtained by AFI/ICP-MS coupled with disk filtration method using iminodiacetate (IDA)-type chelating resin were favorably agreed with the data obtained by AFI/ICP-MS coupled with column preconcentration method using chitosan-based chelating resin. (author)

  12. A novel flow injection chemiluminescence method for automated and miniaturized determination of phenols in smoked food samples.

    Science.gov (United States)

    Vakh, Christina; Evdokimova, Ekaterina; Pochivalov, Aleksei; Moskvin, Leonid; Bulatov, Andrey

    2017-12-15

    An easily performed fully automated and miniaturized flow injection chemiluminescence (CL) method for determination of phenols in smoked food samples has been proposed. This method includes the ultrasound assisted solid-liquid extraction coupled with gas-diffusion separation of phenols from smoked food sample and analytes absorption into a NaOH solution in a specially designed gas-diffusion cell. The flow system was designed to focus on automation and miniaturization with minimal sample and reagent consumption by inexpensive instrumentation. The luminol - N-bromosuccinimide system in an alkaline medium was used for the CL determination of phenols. The limit of detection of the proposed procedure was 3·10 -8 ·molL -1 (0.01mgkg -1 ) in terms of phenol. The presented method demonstrated to be a good tool for easy, rapid and cost-effective point-of-need screening phenols in smoked food samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Flow-injection determination of thorium and uranium after on-line ion-exchange preconcentration in Dowex 50-X8

    International Nuclear Information System (INIS)

    Perez Pavon, J.L.; Garcia Pinto, C.G.; Rodriguez Garcia, Estrella; Moreno Cordero, Bernardo

    1992-01-01

    The preconcentration of thorium and uranium on Dowex 50-X8 was studied as a method for the preconcentration of these cations prior to their determination by flow injection with spectrophotometric detection using Arsenazo III in 3.6 M HCl stabilized with Triton X-100 as chromogenic reagent. The preconcentration device is a minicolumn included in the sample loop of the injection valve. A second valve contains a reducing minicolumn filled with lead powder to reduce U(VI) to U(IV) before the confluence of the sample with the reagent stream. The method can be applied to samples containing 0.5-100 μg l -1 and was tested with different spiked water samples. (author). 15 refs.; 3 figs.; 3 tabs

  14. Determination of thiram in natural waters using flow-injection with cerium(IV)-quinine chemiluminescence system.

    Science.gov (United States)

    Waseem, Amir; Yaqoob, Mohammad; Nabi, Abdul

    2010-01-01

    A simple and rapid flow-injection chemiluminescence method has been developed for the determination of dithiocarbamate fungicide thiram based on the chemiluminescence reaction of thiram with ceric sulfate and quinine in aqueous sulfuric acid. The present method allowed the determination of thiram in the concentration range of 7.5-2500 ng/mL and the detection limit (signal-to-noise ratio = 3) was 7.5 ng/mL with sample throughput of 120/h. The relative standard deviation was 2.5% for 10 replicate analyses of 500 ng/mL thiram. The effects of foreign species including various anions and cations present in water at environmentally relevant concentrations and some pesticides were also investigated. The proposed method was applied to determine thiram in spiked natural waters using octadecyl bonded phase silica (C(18)) cartridges for solid-phase extraction. The recoveries were in the range 99 +/- 1 to 104 +/- 1%. Copyright (c) 2009 John Wiley & Sons, Ltd.

  15. Evaluation of Flow-Injection Tandem Mass Spectrometry for Rapid and High-Throughput Quantitative Determination of B-Vitamins in Nutritional Supplements

    Energy Technology Data Exchange (ETDEWEB)

    Bhandari, Deepak [ORNL; Van Berkel, Gary J [ORNL

    2012-01-01

    The use of flow-injection electrospray ionization tandem mass spectrometry for rapid and high-throughput mass spectral analysis of selected B-vitamins, viz. B1, B2, B3, B5, and B6, in nutritional formulations was demonstrated. A simple and rapid (~5 min) in-tube sample preparation was performed by adding extraction solvent to a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Automated flow injection introduced 1 L of the extracts directly into the mass spectrometer ion source without chromatographic separation. Sample-to-sample analysis time was 60 s representing significant improvement over conventional liquid chromatography approaches which typically require 25-45 min, and often require more significant sample preparation procedures. Quantitative capabilities of the flow-injection analysis were tested using the method of standard additions and NIST standard reference material (SRM 3280) multivitamin/multielement tablets. The quantity determined for each B-vitamin in SRM 3280 was within the statistical range provided for the respective certified values. The same sample preparation and analysis approach was also applied to two different commercial vitamin supplement tablets and proved to be successful in the quantification of the selected B-vitamins as evidenced by an agreement with the labels values and the results obtained using isotope dilution liquid chromatography/mass spectrometry.

  16. Screen-printed sensor for batch and flow injection potentiometric chromium(VI) monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Moreno, Raul A.; Gismera, M.J.; Sevilla, M.T.; Procopio, Jesus R. [Facultad de Ciencias, Universidad Autonoma de Madrid, Departamento de Quimica Analitica y Analisis Instrumental, Madrid (Spain)

    2010-05-15

    A disposable screen-printed electrode was designed and evaluated for direct detection of chromium(VI) in batch and flow analysis. The carbon screen-printed electrode was modified with a graphite-epoxy composite. The optimal graphite-epoxy matrix contains 37.5% graphite powder, 12.5% diphenylcarbohydrazide, a selective compound for chromium(VI), and 50% epoxy resin. The principal analytical parameters of the potentiometric response in batch and flow analysis were optimized and calculated. The screen-printed sensor exhibits a response time of 20 {+-} 1 s. In flow analysis, the analytical frequency of sampling is 70 injections per hour using 0.1 M NaNO{sub 3} solution at pH 3 as the carrier, a flow rate of 2.5 mL.min{sup -1}, and an injection sample volume of 0.50 mL. The sensor shows potentiometric responses that are very selective for chromium(VI) ions and optimal detection limits in both static mode (2.1 x 10{sup -7} M) and online analysis (9.4 x 10{sup -7} M). The disposable potentiometric sensor was employed to determine toxicity levels of chromium(VI) in mineral, tap, and river waters by flow-injection potentiometry and batch potentiometry. Chromium(VI) determination was also carried out with successful results in leachates from municipal solid waste landfills. (orig.)

  17. Flow injection methods for the determination of a-tocopherol with spectrophotometric detection

    International Nuclear Information System (INIS)

    Rishi, L.; Waseem, A.; Yaqoob, M.; Nabi, A.; Jadoon, S.

    2011-01-01

    The present paper describes flow injection procedures for a-tocopherol determination in pharmaceuticals and infant milk powder based on spectrophotometric detection. These two procedures are based on the reduction of iron(III) to iron(II) and of Mo(Vi) to Mo(V) by a-tocopherol and subsequent formation of iron(II)-o-phenanthroline, and phospho molybdenum complexes which were monitored at 510 and 695 nm respectively. Calibration graphs were linear over the concentration range of 0.21-43 mu g/mL for iron(III) and 0.25-10 mu g/mL for Mo(Vi) reduction methods respectively. The limits of detection (3s) of 0.05 and 0.1 mu g/mL with sample throughput of 30 and 50/h respectively were obtained. The relative standard deviations of 1.2- 3.8% (n = 4) was achieved in the concentration range studied. The developed methods were applied to pharmaceuticals and infant milk powders and the results obtained were compared with official method and no significant difference between these methods was observed at 95% confidence level. (author)

  18. Determination of As(III) and As(V) by Flow Injection-Hydride Generation-Atomic Absorption Spectrometry via On-line Reduction of As(V) by KI

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Hansen, Elo Harald

    1997-01-01

    A volume-based flow injection (FI) procedure is described for the determination and speciation of trace inorganic arsenic, As(III) and As(V), via hydride generation-atomic absorption spectrometry (HG-AAS) of As(III). The determination of total arsenic is obtained by on-line reduction of As(V) to As...

  19. Flow injection analysis-flame atomic absorption spectrometry system for indirect determination of sulfite after on-line reduction of solid-phase manganese (IV) dioxide reactor.

    Science.gov (United States)

    Zare-Dorabei, Rouholah; Boroun, Shokoufeh; Noroozifar, Meissam

    2018-02-01

    A new and simple flow injection method followed by atomic absorption spectrometry was developed for indirect determination of sulfite. The proposed method is based on the oxidation of sulfite to sulphate ion using solid-phase manganese dioxide (30% W/W suspended on silica gel beads) reactor. MnO 2 will be reduced to Mn(II) by sample injection in to the column under acidic carrier stream of HNO 3 (pH 2) with flow rate of 3.5mLmin -1 at room temperature. Absorption measurement of Mn(II) which is proportional to the concentration of sulfite in the sample was carried out by atomic absorption spectrometry. The calibration curve was linear up to 25mgL -1 with a detection limit (DL) of 0.08mgL -1 for 400µL injection sample volume. The presented method is efficient toward sulfite determination in sugar and water samples with a relative standard deviation (RSD) less than 1.2% and a sampling rate of about 60h -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Phenylboronic acid immunoaffinity reactor coupled with flow injection chemiluminescence for determination of {alpha}-fetoprotein

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yafeng [Jiangsu Provincial Key Lab of Biomaterials and Biodevices, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 210096 (China); Zhuang Yafeng [Department of Chemistry, Changzhou Institute of Technology, Changzhou 213022 (China); Liu Songqin [Jiangsu Provincial Key Lab of Biomaterials and Biodevices, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 210096 (China)], E-mail: liusq@seu.edu.cn; He Lin [Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204 (United States)

    2008-12-23

    A reusable and sensitive immunoassay based on phenylboronic acid immunoaffinity reactor in combination with flow injection chemiluminescence (CL) for determination of glycoprotein was described. The reactor was fabricated by immobilizing 3-aminophenylboronic acid (APBA) on glass microbeads with {gamma}-glycidoxypropyltrimethoxysilane (GPMS) as linkage. The {alpha}-fetoprotein (AFP) could be easily immobilized on the APBA coated beads through sugar-boronic interaction. After an off-line incubation, the mixture of the analyte AFP with horseradish peroxidase-labeled AFP antibody (HRP-anti-AFP) was injected into the reactor. This led the trapping of free HRP-anti-AFP by the surface coated AFP on glass beads. The trapped HRP-anti-AFP was detected by chemiluminescence due to its sensitizing effect on the reaction of luminol and hydrogen peroxide. Under optimal conditions, the chemiluminescent signal was proportional to AFP concentration in the range of 10-100 ng mL{sup -1}. The whole assay process including regeneration of the reactor could be completed within 31 min. The proposed system showed acceptable detection and fabrication reproducibility, and the results obtained with the present method were in acceptable agreement with those from parallel single-analyte test of practical clinical sera. The described method enabled a low-cost, time saving and was potential to detect the serum AFP level in clinical diagnosis.

  1. Exploiting flow injection and sequential injection for trace metal determinations in conjunction with detection by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    and selectivity. Either in order to separate/preconcentrate the analyte material, or because of the presence of potentially interfering matrix constituents. Such pretreatments are advantageously performed in flow injection (FI) or sequential injection (SI) manifolds, where all appropriate unit operations can...

  2. On-line dynamic fractionation and automatic determination of inorganic phosphorous in environmental solid substrates exploiting sequential injection microcolumn extraction and flow injection analysi

    DEFF Research Database (Denmark)

    Buanuam, Janya; Miró, Manuel; Hansen, Elo Harald

    2006-01-01

    Sequential injection microcolumn extraction (SI-MCE) based on the implementation of a soil containing microcartridge as external reactor in a sequential injection network is, for the first time, proposed for dynamic fractionation of macronutrients in environmental solids, as exemplified by the pa......Sequential injection microcolumn extraction (SI-MCE) based on the implementation of a soil containing microcartridge as external reactor in a sequential injection network is, for the first time, proposed for dynamic fractionation of macronutrients in environmental solids, as exemplified...... by the partitioning of inorganic phosphorous in agricultural soils. The on-line fractionation method capitalises on the accurate metering and sequential exposure of the various extractants to the solid sample by application of programmable flow as precisely coordinated by a syringe pump. Three different soil phase...... associations for phosphorus, that is, exchangeable, Al- and Fe-bound and Ca-bound fractions, were elucidated by accommodation in the flow manifold of the 3 steps of the Hietjles-Litjkema (HL) scheme involving the use of 1.0 M NH4Cl, 0.1 M NaOH and 0.5 M HCl, respectively, as sequential leaching reagents...

  3. Flow Injection Analysis in Industrial Biotechnology

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Miró, Manuel

    2009-01-01

    Flow injection analysis (FIA) is an analytical chemical continuous-flow (CF) method which in contrast to traditional CF-procedures does not rely on complete physical mixing (homogenisation) of the sample and the reagent(s) or on attaining chemical equilibria of the chemical reactions involved. Ex...

  4. Application of direct-injection detector integrated with the multi-pumping flow system to chemiluminescence determination of the total polyphenol index.

    Science.gov (United States)

    Nalewajko-Sieliwoniuk, Edyta; Iwanowicz, Magdalena; Kalinowski, Sławomir; Kojło, Anatol

    2016-03-10

    In this work, we present a novel chemiluminescence (CL) method based on direct-injection detector (DID) integrated with the multi-pumping flow system (MPFS) to chemiluminescence determination of the total polyphenol index. In this flow system, the sample and the reagents are injected directly into the cone-shaped detection cell placed in front of the photomultiplier window. Such construction of the detection chamber allows for fast measurement of the CL signal in stopped-flow conditions immediately after mixing the reagents. The proposed DID-CL-MPFS method is based on the chemiluminescence of nanocolloidal manganese(IV)-hexametaphosphate-ethanol system. The application of ethanol as a sensitizer, eliminated the use of carcinogenic formaldehyde. Under the optimized experimental conditions, the chemiluminescence intensities are proportional to the concentration of gallic acid in the range from 5 to 350 ng mL(-1). The DID-CL-MPFS method offers a number of advantages, including low limit of detection (0.80 ng mL(-1)), high precision (RSD = 3.3%) and high sample throughput (144 samples h(-1)) as well as low consumption of reagents, energy and low waste generation. The proposed method has been successfully applied to determine the total polyphenol index (expressed as gallic acid equivalent) in a variety of plant-derived food samples (wine, tea, coffee, fruit and vegetable juices, herbs, spices). Copyright © 2016 Elsevier B.V. All rights reserved.

  5. The effects of arbitrary injection angle and flow conditions on venturi-jet mixer

    Directory of Open Access Journals (Sweden)

    Sundararaj S.

    2012-01-01

    Full Text Available This paper describes the effect of jet injection angle, cross flow Reynolds number and velocity ratio on entrainment and mixing of jet with incompressible cross flow in venturi-jet mixer. Five different jet injection angles 45o, 60o, 90o, 125o, 135o are tested to evaluate the entrainment of jet and mixing performances of the mixer. Tracer concentration along the downstream of the jet injection, cross flow velocity, jet velocity and pressure drop across the mixer are determined experimentally to characterize the mixing performance of the mixer. The experiments show that the performance of a venturi-jet-mixer substantially improves at high injection angle and can be augmented still by increasing velocity ratio. The jet deflects much and penetrates less in the cross flow as the cross flow Reynolds number is increased. The effect could contribute substantially to the better mixing index with moderate pressure drop. Normalized jet profile, concentration decay, jet velocity profile are computed from equations of conservation of mass, momentum and concentration written in natural co-ordinate systems. The comparison between the experimental and numerical results confirms the accuracy of the simulations. Correlations for jet trajectory and entrainment ratio of the mixer are obtained by multivariate-linear regression analysis using power law.

  6. Determinação potenciométrica em fluxo de cloreto de cetilpiridinio em desinfectantes bucais Potentiometric determination of cetylpyridinium chloride in oral desinfectants by flow injection analysis

    Directory of Open Access Journals (Sweden)

    Paula C. S. Baptista

    2003-08-01

    Full Text Available The work describes a new procedure for cetylpyridinium chloride determination in oral disinfectants, based on a flow-injection system with potentiometric detection. The determination was based on the measurement of picrate concentration decrease as result of ion-pair reaction with the analyte present in the injected sample. In the optimised set-up the sample injection volume was kept at 400 µL and merged downstream with the reagent solution containing 1,0 x10-5 mol/L of picrate adjusted to pH 5.0 with citrate/citric acid buffer. The flow rate was fixed at 8 mL/min and the reactor length at 40 cm. The proposed procedure enables the determination of cetylpyridinium in the analytical range of 5,0x10-6 - 7,5x10-5 mol/L at a sampling rate of 60/h. The results for real samples had a precision better than 3% and were comparable to the labelled values.

  7. Spectrophotometric determination of uranium and thorium with arsenazo III in the flow injection system

    International Nuclear Information System (INIS)

    Andrade, M. das G.M. de.

    1986-12-01

    A simple system for flow injection analysis (FIA) with double confluence was built using a filter photocolorimeter, an analogic potentiometer, 'plexiglass' flow cuvettes, polyethylene colls and tubes, 'plexiglass' commuter and peristaltic pump to introduce solutions and gravity as flow source. The system was dimensioned and studied using only Arsenazo III solutions. Spectrophotometric methods for uranium and thorium using Arsenazo III were studied using a scanning spectrophotometer and after chosing adequate red filter, adapted to photocolorimetry using flow cuvettes and FIA. Synthetic samples, phosphate rock, and process samples from uranium recovery of dolomites were analysed. Rocks of Morro do Ferro (MG, Brazil), Caldasite (Baddeleyte + Zirconite), Zirconite, Monazite from a program for certification and certified rocks (Dunite DC-1, CANMET) were analysed without chemical separation of Th (IV) and with ion exchange separation in semi-micro columns of cation exchange resin (Dowex 50). (Author) [pt

  8. Sequential injection lab-on-valve: the third generation of flow injection analysis

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2003-01-01

    Termed the third generation of flow injection analysis, sequential injection (SI)-lab-on-valve (LOV) has specific advantages and allows novel, unique applications - not least as a versatile front end to a variety of detection techniques. This review presents snd discusses progress to date of the ...

  9. Automated injection of slurry samples in flow-injection analysis

    NARCIS (Netherlands)

    Hulsman, M.H.F.M.; Hulsman, M.; Bos, M.; van der Linden, W.E.

    1996-01-01

    Two types of injectors are described for introducing solid samples as slurries in flow analysis systems. A time-based and a volume-based injector based on multitube solenoid pinch valves were built, both can be characterized as hydrodynamic injectors. Reproducibility of the injections of dispersed

  10. Flow improvers for water injection based on surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Oskarsson, H.; Uneback, I.; Hellsten, M.

    2006-03-15

    In many cases it is desirable to increase the flow of injection water when an oil well deteriorates. It is very costly in offshore operation to lay down an additional water pipe to the injection site. Flow improvers for the injection water will thus be the most cost-effective way to increase the flow rate. During the last years water-soluble polymers have also been applied for this purpose. These drag-reducing polymers are however only slowly biodegraded which has been an incentive for the development of readily biodegradable surfactants as flow improvers for injection water. A combination of a zwitterionic and an anionic surfactant has been tested in a 5.5 inch, 700 m long flow loop containing sulphate brine with salinity similar to sea water. A drag reduction between 75 and 80% was achieved with 119 ppm in solution of the surfactant blend at an average velocity of 1.9 m/s and between 50 and 55% at 2.9 m/s. The surfactants in this formulation were also found to be readily biodegradable in sea water and low bio accumulating which means they have an improved environmental profile compared to the polymers used today. Due to the self-healing properties of the drag-reducing structures formed by surfactants, these may be added before the pump section - contrary to polymers which are permanently destroyed by high shear forces. (Author)

  11. Reverse flow injection spectrophotometric determination of thiram and nabam fungicides in natural water samples

    International Nuclear Information System (INIS)

    Asghar, M.; Yaqoob, M.; Nabi, A.

    2014-01-01

    A reverse flow injection (rFI) spectrophotometric method is reported for determination of thiram and nabam fungicides in natural water samples. The method is based on the reduction of iron(III) in the presence of thiram/nabam in acidic medium at 60 degree C and formation of iron(II)-ferricyanide complex was measured at 790 nm. The limits of detection (3s blank) were 0.01 and 0.05 micro g mL1 for thiram and nabam respectively with a sample throughput of 60 h1. Calibration graphs were linear over the range of 0.02 - 8.0 micro g mL1 (R2 = 0.9999, n = 8) and 0.1 - 30 micro g mL1 (R2 = 0.9982, n = 10) for thiram and nabam with relative standard deviations (RSDs; n = 3) in the range of 0.8 - 1.6% respectively. Experimental parameters and potential interferences were examined. Thiram and nabam were determined in natural water samples using solid-phase extraction (SPE) procedure and recoveries were in the range of 93+-3 - 105+-2% and 87+-4 - 102+-3% respectively. The results obtained were not significantly different compared with a HPLC method. (author)

  12. A multisyringe flow injection method for the determination of thorium in water samples using spectrophotometric detection

    International Nuclear Information System (INIS)

    Guzman-Mar, J.L.; Aracely Hernandez-Ramirez; Lopez-Chuken, U.J.; Lopez-de-Alba, P.L.; Victor Cerda

    2011-01-01

    A fast and simple multisyringe flow injection analysis (MSFIA) method for routine determination of thorium in water samples was developed. The methodology was based on the complexation reaction of thorium with arsenazo (III) at pH 2.0. Thorium concentrations were spectrophotometrically detected at 665 nm. Under optimal conditions, Beer's law was obeyed over the range from 0.2 to 4.5 μg mL -1 thorium, a 3σ detection limit of 0.05 μg mL -1 , and a 10σ quantification limit of 0.2 μg mL -1 were obtained. The relative standard deviations (RSD, %) at 0.5, 2.5 and 4.5 μg mL -1 was 2.8, 1.5 and 0.8%, respectively (n = 10). It was found that most of the common metal ions and anions did not interfere with the thorium determination. The proposed method was successfully applied to its analysis in various water samples. (author)

  13. Flow injection on-line spectrophotometric determination of thorium(IV) after preconcentration on XAD-4 resin impregnated with oxytetracycline

    Energy Technology Data Exchange (ETDEWEB)

    Shahida, Shabnam; Khan, Muhammad Haleem [Univ. of Azad Jammu and Kashmir, Muzaffarabad (Pakistan). Dept. of Chemistry; Ali, Akbar [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

    2014-02-15

    A very sensitive, selective and simple flow injection time-based method was developed for on-line preconcentration and determination of thorium(IV) at micro g L{sup -1} levels in environmental samples. The system operation was based on thorium(IV) ion retention at pH 4.0 in the minicolumn at a flow rate of 15.2 mL min{sup -1}. The trapped complex was then eluted with 3.6 mol L{sup -1} HCl at a flow rate of 4.9 mL min{sup -1}. The amount of thorium(IV) in the eluate was measured spectrophotometrically at 651 nm using arsenazo-III solution (0.05 % in 3.6 mol L{sup -1} HCl stabilized with 1 % triton X-100, 4.9 mL min{sup -1}) as colorimetric reagent. All chemical, and flow injection variables were optimized for the quantitative preconcentration of metal and a study of interference level of various ions was also carried out. The system offered low backpressure and improved sensitivity and selectivity. At a preconcentration time of 60 s and a sample frequency of 40 h{sup -1}, the enhancement factor was 97, the detection limit was 0.25 μg L{sup -1}, and the precision expressed as relative standard deviation was 1.08 % (at 50 μg L{sup -1}), whereas for 300 s of the preconcentration time and a sample frequency of 10 h{sup -1}, the enhancement factor of 357, the detection limit (3s) of 0.069 μg L{sup -1} and the precision of 1.32 % (at 10 μg L{sup -1}) was reported. The accuracy of the developed method was sufficient and evaluated by the analysis of certified reference material IAEA-SL-1 (Lake Sediment) and spiked water samples.

  14. Flow injection on-line spectrophotometric determination of thorium(IV) after preconcentration on XAD-4 resin impregnated with oxytetracycline

    International Nuclear Information System (INIS)

    Shahida, Shabnam; Khan, Muhammad Haleem; Ali, Akbar

    2014-01-01

    A very sensitive, selective and simple flow injection time-based method was developed for on-line preconcentration and determination of thorium(IV) at micro g L"-"1 levels in environmental samples. The system operation was based on thorium(IV) ion retention at pH 4.0 in the minicolumn at a flow rate of 15.2 mL min"-"1. The trapped complex was then eluted with 3.6 mol L"-"1 HCl at a flow rate of 4.9 mL min"-"1. The amount of thorium(IV) in the eluate was measured spectrophotometrically at 651 nm using arsenazo-III solution (0.05 % in 3.6 mol L"-"1 HCl stabilized with 1 % triton X-100, 4.9 mL min"-"1) as colorimetric reagent. All chemical, and flow injection variables were optimized for the quantitative preconcentration of metal and a study of interference level of various ions was also carried out. The system offered low backpressure and improved sensitivity and selectivity. At a preconcentration time of 60 s and a sample frequency of 40 h"-"1, the enhancement factor was 97, the detection limit was 0.25 μg L"-"1, and the precision expressed as relative standard deviation was 1.08 % (at 50 μg L"-"1), whereas for 300 s of the preconcentration time and a sample frequency of 10 h"-"1, the enhancement factor of 357, the detection limit (3s) of 0.069 μg L"-"1 and the precision of 1.32 % (at 10 μg L"-"1) was reported. The accuracy of the developed method was sufficient and evaluated by the analysis of certified reference material IAEA-SL-1 (Lake Sediment) and spiked water samples.

  15. Modeling and flow analysis of pure nylon polymer for injection molding process

    International Nuclear Information System (INIS)

    Nuruzzaman, D M; Kusaseh, N; Basri, S; Hamedon, Z; Oumer, A N

    2016-01-01

    In the production of complex plastic parts, injection molding is one of the most popular industrial processes. This paper addresses the modeling and analysis of the flow process of the nylon (polyamide) polymer for injection molding process. To determine the best molding conditions, a series of simulations are carried out using Autodesk Moldflow Insight software and the processing parameters are adjusted. This mold filling commercial software simulates the cavity filling pattern along with temperature and pressure distributions in the mold cavity. In the modeling, during the plastics flow inside the mold cavity, different flow parameters such as fill time, pressure, temperature, shear rate and warp at different locations in the cavity are analyzed. Overall, this Moldflow is able to perform a relatively sophisticated analysis of the flow process of pure nylon. Thus the prediction of the filling of a mold cavity is very important and it becomes useful before a nylon plastic part to be manufactured. (paper)

  16. Modeling and flow analysis of pure nylon polymer for injection molding process

    Science.gov (United States)

    Nuruzzaman, D. M.; Kusaseh, N.; Basri, S.; Oumer, A. N.; Hamedon, Z.

    2016-02-01

    In the production of complex plastic parts, injection molding is one of the most popular industrial processes. This paper addresses the modeling and analysis of the flow process of the nylon (polyamide) polymer for injection molding process. To determine the best molding conditions, a series of simulations are carried out using Autodesk Moldflow Insight software and the processing parameters are adjusted. This mold filling commercial software simulates the cavity filling pattern along with temperature and pressure distributions in the mold cavity. In the modeling, during the plastics flow inside the mold cavity, different flow parameters such as fill time, pressure, temperature, shear rate and warp at different locations in the cavity are analyzed. Overall, this Moldflow is able to perform a relatively sophisticated analysis of the flow process of pure nylon. Thus the prediction of the filling of a mold cavity is very important and it becomes useful before a nylon plastic part to be manufactured.

  17. Recent Development in Optical Chemical Sensors Coupling with Flow Injection Analysis

    Directory of Open Access Journals (Sweden)

    Fuensanta Sánchez Rojas

    2006-10-01

    Full Text Available Optical techniques for chemical analysis are well established and sensors based on thesetechniques are now attracting considerable attention because of their importance in applications suchas environmental monitoring, biomedical sensing, and industrial process control. On the other hand,flow injection analysis (FIA is advisable for the rapid analysis of microliter volume samples and canbe interfaced directly to the chemical process. The FIA has become a widespread automatic analyticalmethod for more reasons; mainly due to the simplicity and low cost of the setups, their versatility, andease of assembling. In this paper, an overview of flow injection determinations by using opticalchemical sensors is provided, and instrumentation, sensor design, and applications are discussed. Thiswork summarizes the most relevant manuscripts from 1980 to date referred to analysis using opticalchemical sensors in FIA.

  18. Optimized and validated flow-injection spectrophotometric analysis of topiramate, piracetam and levetiracetam in pharmaceutical formulations.

    Science.gov (United States)

    Hadad, Ghada M; Abdel-Salam, Randa A; Emara, Samy

    2011-12-01

    Application of a sensitive and rapid flow injection analysis (FIA) method for determination of topiramate, piracetam, and levetiracetam in pharmaceutical formulations has been investigated. The method is based on the reaction with ortho-phtalaldehyde and 2-mercaptoethanol in a basic buffer and measurement of absorbance at 295 nm under flow conditions. Variables affecting the determination such as sample injection volume, pH, ionic strength, reagent concentrations, flow rate of reagent and other FIA parameters were optimized to produce the most sensitive and reproducible results using a quarter-fraction factorial design, for five factors at two levels. Also, the method has been optimized and fully validated in terms of linearity and range, limit of detection and quantitation, precision, selectivity and accuracy. The method was successfully applied to the analysis of pharmaceutical preparations.

  19. Flow-injection determination of total organic fluorine with off-line defluorination reaction on a solid sorbent bed.

    Science.gov (United States)

    Musijowski, Jacek; Trojanowicz, Marek; Szostek, Bogdan; da Costa Lima, José Luis Fontes; Lapa, Rui; Yamashita, Hiroki; Takayanagi, Toshio; Motomizu, Shoji

    2007-09-26

    Considering recent reports on widespread occurrence and concerns about perfluoroalkyl substances (PFAS) in environmental and biological systems, analysis of these compounds have gained much attention in recent years. Majority of analyte-specific methods are based on a LC/MS/MS or a GC/MS detection, however many environmental or biological studies would benefit from a total organic fluorine (TOF) determination. Presented work was aimed at developing a method for TOF determination. TOF is determined as an amount of inorganic fluoride obtained after defluorination reaction conducted off-line using sodium biphenyl reagent directly on the sorbent without elution of retained analytes. Recovered fluoride was analyzed using flow-injection system with either fluorimetric or potentiometric detection. The TOF method was tested using perfluorocarboxylic acids (PFCA), including perfluorooctanoic acid (PFOA), as model compounds. Considering low concentrations of PFAS in natural samples, solid-phase extraction as a preconcentration procedure was evaluated. Several carbon-based sorbents were tested, namely multi-wall carbon nanotubes, carbon nanofibres and activated carbon. Good sorption of all analytes was achieved and defluorination reaction was possible to carry out directly on a sorbent bed. Recoveries obtained for PFCAs, adsorbed on an activated carbon sorbent, and measured as TOF, were 99.5+/-1.7, 110+/-9.4, 95+/-26, 120+/-32, 110+/-12 for C4, C6, C8, C10 and C12-PFCA, respectively. Two flow systems that would enable the defluorination reaction and fluoride determination in a single system were designed and tested.

  20. Simultaneous Determination of Iron, Copper and Cobalt in Food Samples by CCD-diode Array Detection-Flow Injection Analysis with Partial Least Squares Calibration Model

    International Nuclear Information System (INIS)

    Mi Jiaping; Li Yuanqian; Zhou Xiaoli; Zheng Bo; Zhou Ying

    2006-01-01

    A flow injection-CCD diode array detection spectrophotometry with partial least squares (PLS) program for simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction of the three metal ions and 2- (5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP in acetic acid - sodium acetate buffer solution (pH5) with Triton X-100 and ascorbic acid. The overlapped spectra of the colored complexes were collected by charge-coupled device (CCD) - diode array detector and the multi-wavelength absorbance data was processed using partial least squares (PLS) algorithm. Optimum reaction conditions and parameters of flow injection analysis were investigated. The samples of tea, sesame, laver, millet, cornmeal, mung bean and soybean powder were determined by the proposed method. The average recoveries of spiked samples were 91.80%∼100.9% for Iron, 92.50%∼108.0% for Copper, 93.00%∼110.5% for Cobalt, respectively with relative standard deviation (R.S.D) of 1.1%∼12.1%. The sampling rate is 45 samples h -1 . The determination results of the food samples were in good agreement between the proposed method and ICP-AES

  1. Simultaneous Determination of Iron, Copper and Cobalt in Food Samples by CCD-diode Array Detection-Flow Injection Analysis with Partial Least Squares Calibration Model

    Energy Technology Data Exchange (ETDEWEB)

    Mi Jiaping; Li Yuanqian; Zhou Xiaoli; Zheng Bo; Zhou Ying [West China School of Public Health, Sichuan University, Chengdu, 610041 (China)

    2006-01-01

    A flow injection-CCD diode array detection spectrophotometry with partial least squares (PLS) program for simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction of the three metal ions and 2- (5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP in acetic acid - sodium acetate buffer solution (pH5) with Triton X-100 and ascorbic acid. The overlapped spectra of the colored complexes were collected by charge-coupled device (CCD) - diode array detector and the multi-wavelength absorbance data was processed using partial least squares (PLS) algorithm. Optimum reaction conditions and parameters of flow injection analysis were investigated. The samples of tea, sesame, laver, millet, cornmeal, mung bean and soybean powder were determined by the proposed method. The average recoveries of spiked samples were 91.80%{approx}100.9% for Iron, 92.50%{approx}108.0% for Copper, 93.00%{approx}110.5% for Cobalt, respectively with relative standard deviation (R.S.D) of 1.1%{approx}12.1%. The sampling rate is 45 samples h{sup -1}. The determination results of the food samples were in good agreement between the proposed method and ICP-AES.

  2. Simultaneous Determination of Iron, Copper and Cobalt in Food Samples by CCD-diode Array Detection-Flow Injection Analysis with Partial Least Squares Calibration Model

    Science.gov (United States)

    Mi, Jiaping; Li, Yuanqian; Zhou, Xiaoli; Zheng, Bo; Zhou, Ying

    2006-01-01

    A flow injection-CCD diode array detection spectrophotometry with partial least squares (PLS) program for simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction of the three metal ions and 2- (5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP in acetic acid - sodium acetate buffer solution (pH5) with Triton X-100 and ascorbic acid. The overlapped spectra of the colored complexes were collected by charge-coupled device (CCD) - diode array detector and the multi-wavelength absorbance data was processed using partial least squares (PLS) algorithm. Optimum reaction conditions and parameters of flow injection analysis were investigated. The samples of tea, sesame, laver, millet, cornmeal, mung bean and soybean powder were determined by the proposed method. The average recoveries of spiked samples were 91.80%~100.9% for Iron, 92.50%~108.0% for Copper, 93.00%~110.5% for Cobalt, respectively with relative standard deviation (R.S.D) of 1.1%~12.1%. The sampling rate is 45 samples h-1. The determination results of the food samples were in good agreement between the proposed method and ICP-AES.

  3. Investigations into the Role of Modifiers for Entrapment of Hydrides in Flow Injection Hydride Generation Electrothermal Atomic Absorption Spectrometry as Exemplified for the Determination of Germanium

    DEFF Research Database (Denmark)

    Hilligsøe, Bo; Andersen, Jens Enevold Thaulov; Hansen, Elo Harald

    1997-01-01

    Pd-conditioned graphite tubes, placed in the furnace of an atomic absorption spectrometry instrument, are used for entrapment of germane as generated in an associated flow injection system. Two different approaches are tested with the ultimate aim to allow multiple determinations, that is...

  4. Down scaled Kjeldahl digestion and flow injection conductometric system for determination of protein content in some traditional northern Thai foods.

    Science.gov (United States)

    Yanu, Pattama; Jakmunee, Jaroon

    2017-09-01

    A flow injection conductometric (FIC) system for determination of total Kjeldahl nitrogen (TKN) was developed for estimating total protein content in food. A small scale Kjeldahl digestion was performed with a short digestion time of only 20min. The digested solution was injected into the FIC system, and TKN was converted to ammonia gas in an alkaline donor stream of the system. The gas diffused through a membrane and dissolved into an acceptor stream causing an increase in conductivity as detected by a detector and recorded as a peak. Under the optimum condition, a linear calibration graph in the range of 4.00-100.00mgL -1 was obtained with LOD of 0.05mgL -1 . A good precision (0.04% RSD, n=11, 30.00mgNL -1 ) and high sample throughput of 72h -1 was achieved. The method was applied for determination of protein in some traditional northern Thai foods, revealing that they are good sources of proteins. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Enhancement of melting heat transfer of ice slurries by an injection flow in a rectangular cross sectional horizontal duct

    International Nuclear Information System (INIS)

    Fujii, Kota; Yamada, Masahiko

    2013-01-01

    Ice slurries are now commonly used as cold thermal storage materials, and have the potential to be applied to other engineering fields such as quenching metals to control properties, emergency cooling systems, and preservation of food and biomaterials at low temperatures. Although ice slurries have been widely utilized because of their high thermal storage densities, previous studies have revealed that the latent heat of ice particles is not completely released on melting because of insufficient contact between the ice particles and a heated surface. In this study, an injection flow that was bifurcated from the main flow of an ice slurry was employed to promote melting heat transfer of ice particles on a horizontal heated surface. The effects of injection angle and injection flow rate on local heat transfer coefficients and heat transfer coefficient ratios were determined experimentally. The results show that from two to three times higher heat transfer coefficients can be obtained by using large injection flow rates and injection angles. However, low injection angles improved the utilization rate of the latent heat of ice near the injection point by approximately a factor of two compared to that without injection. -- Highlights: • Melting of ice slurries were enhanced by the injection under constant total flow rate. • Contribution of ice particles and their latent heat to heat transfer was investigated. • Effect of velocity ratio of injection to that of main flow was examined. • Effect of the angle of injection flow to the main flow was also examined. • Appropriate conditions for the use of latent heat of ice and heat transfer did not coincide

  6. Reagent-free determination of amikacin content in amikacin sulfate injections by FTIR derivative spectroscopy in a continuous flow system

    Directory of Open Access Journals (Sweden)

    José F. Ovalles

    2014-04-01

    Full Text Available The quantitative estimation of amikacin (AMK in AMK sulfate injection samples is reported using FTIR-derivative spectrometric method in a continuous flow system. Fourier transform of mid-IR spectra were recorded without any sample pretreatment. A good linear calibration (r>0.999, %RSD<2.0 in the range of 7.7–77.0 mg/mL was found. The results showed a good correlation with the manufacturer's and overall they all fell within acceptable limits of most pharmacopoeial monographs on AMK sulfate. Keywords: Amikacin, FTIR derivative spectrometry, Continuous flow system, Pharmaceutical preparation, Injection, Sulfate

  7. Wavelet transform for the evaluation of peak intensities in flow-injection analysis

    NARCIS (Netherlands)

    Bos, M.; Hoogendam, E.

    1992-01-01

    The application of the wavelet transform in the determination of peak intensities in flow-injection analysis was studied with regard to its properties of minimizing the effects of noise and baseline drift. The results indicate that for white noise and a favourable peak shape a signal-to-noise ratio

  8. Wavelett transform for the evaluation of peak intensities in flow-injection analysis

    NARCIS (Netherlands)

    Bos, M.; Hoogendam, E.; Hoogendam, E.

    1992-01-01

    The application of the wavelet transform in the determination of peak intensities in flow-injection analysis was studied with regard to its properties of minimizing the effects of noise and baseline drift. The results indicate that for white noise and a favourable peak shape a signal-to-noise ratio

  9. 3D-CFD Simulation of Confined Cross-Flow Injection Process Using Single Piston Pump

    Directory of Open Access Journals (Sweden)

    M. Elashmawy

    2017-12-01

    Full Text Available Injection process into a confined cross flow is quite important for many applications including chemical engineering and water desalination technology. The aim of this study is to investigate the performance of the injection process into a confined cross-flow of a round pipe using a single piston injection pump. A computational fluid dynamics (CFD analysis has been carried out to investigate the effect of the locations of the maximum velocity and minimum pressure on the confined cross-flow process. The jet trajectory is analyzed and related to the injection pump shaft angle of rotation during the injection duty cycle by focusing on the maximum instant injection flow of the piston action. Results indicate a low effect of the jet trajectory within the range related to the injection pump operational conditions. Constant cross-flow was used and injection flow is altered to vary the jet to line flow ratio (QR. The maximum jet trajectory exhibits low penetration inside the cross-flow. The results showed three regions of the flow ratio effect zones with different behaviors. Results also showed that getting closer to the injection port causes a significant decrease on the locations of the maximum velocity and minimum pressure.

  10. Optimization of a flow injection analysis system for multiple solvent extraction

    International Nuclear Information System (INIS)

    Rossi, T.M.; Shelly, D.C.; Warner, I.M.

    1982-01-01

    The performance of a multistage flow injection analysis solvent extraction system has been optimized. The effect of solvent segmentation devices, extraction coils, and phase separators on performance characteristics is discussed. Theoretical consideration is given to the effects and determination of dispersion and the extraction dynamics within both glass and Teflon extraction coils. The optimized system has a sample recovery similar to an identical manual procedure and a 1.5% relative standard deviation between injections. Sample throughput time is under 5 min. These characteristics represent significant improvements over the performance of the same system before optimization. 6 figures, 2 tables

  11. Method for 236U Determination in Seawater Using Flow Injection Extraction Chromatography and Accelerator Mass Spectrometry

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Steier, Peter

    2015-01-01

    An automated analytical method implemented in a flow injection (FI) system was developed for rapid determination of 236U in 10 L seawater samples. 238U was used as a chemical yield tracer for the whole procedure, in which extraction chromatography (UTEVA) was exploited to purify uranium, after...... experimental parameters affecting the analytical effectiveness were investigated and optimized in order to achieve high chemical yields and simple and rapid analysis as well as low procedure background. Besides, the operational conditions for the target preparation prior to the AMS measurement were optimized......, on the basis of studying the coprecipitation behavior of uranium with iron hydroxide. The analytical results indicate that the developed method is simple and robust, providing satisfactory chemical yields (80−100%) and high analysis speed (4 h/sample), which could be an appealing alternative to conventional...

  12. Lanthanides determination in red wine using ultrasound assisted extraction, flow injection, aerosol desolvation and ICP-MS.

    Science.gov (United States)

    Bentlin, Fabrina R S; dos Santos, Clarissa M M; Flores, Erico M M; Pozebon, Dirce

    2012-01-13

    This paper deals with the determination of the fourteen naturally occurring elements of the lanthanide series in red wine. Ultrasound (US) was used for sample preparation prior lanthanides determination using ICP-MS. Flow injection (FI) and pneumatic nebulization/aerosol desolvation were used for nebulization of aliquots of 50 μL of sample and its subsequent transportation to plasma. Sample preparation procedures, matrix interference and time of sonication were evaluated. Better results for lanthanides in red wine were obtained by sonication with US probe for 90 s and sample 10-fold diluted. The limits of detection of La, Ce, Nd, Sm, Gd, Pr, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb were 6.57, 10.8, 9.97, 9.38, 2.71, 1.29, 1.22, 0.52, 2.35, 0.96, 2.30, 0.45, 0.24 and 1.35 ng L(-1), respectively. Red wines of different varieties from three countries of South America were discriminated according to the country of origin by means of multivariate analysis of lanthanides concentration. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Polarographic study of acrolein and its determination by flow injection with amperometric detection at a mercury electrode.

    Science.gov (United States)

    Naranjo Rodríguez, I; Muñoz Leyva, J A; Hidalgo Hidalgo de Cisneros, J L

    1996-07-01

    A study of the electrochemical behavior of acrolein at a dropping mercury electrode using different polarographic techniques is described. Theoretical studies of the reversibility of the wave of acrolein were carried out using two different polarographic techniques: direct current tast and differential pulse. Differential pulse polarography may be used to determine acrolein concentration in a Britton-Robinson buffer solution of pH 10 in the ranges 2 x 10(-7)10(-8) and 5 x 10(-8)-10(-4) mol dm(-3) and a coefficient of variation of 1.7% for a concentration of 10(-5)mol dm(-3). A flow injection method with amperometric detection at a potential of -1.4V using a mercury electrode is also described. Before each injection, any drop hanging from the tip of the capillary needs to be dislodged and a new electrode drop dispensed; three different drop sizes were tested. A linear relationship between peak intensity and acrolein concentration was obtained in the range 10(-5)-10(-7) mol dm(-3), with a detection limit of 9.8 x 10(-8) mol dm(-) 3 and a coefficient of variation of 2.9% for a 2 x 10(-7) mol dm(-3) concentration. Several organic and inorganic species were tested in order to ascertain whether they interfered with the signal for acrolein. The proposed methods were applied to the determination of acrolein in seawater samples.

  14. Simple flow injection for determination of sulfite by amperometric detection using glassy carbon electrode modified with carbon nanotubes-PDDA-gold nanoparticles.

    Science.gov (United States)

    Amatatongchai, Maliwan; Sroysee, Wongduan; Chairam, Sanoe; Nacapricha, Duangjai

    2015-02-01

    A new approach is presented for sensitive and selective measurement of sulfite (SO3(2-)) in beverages based on a simple flow injection system with amperometric detection. In this work, the sulfite sensor was a glassy carbon electrode modified with multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-gold nanoparticles composites (CNTs-PDDA-AuNPs/GC). Electrochemical oxidation of sulfite with this electrode was first studied in 0.1M phosphate buffer (pH 7.0) using cyclic voltammetry. The results indicated that the CNTs-PDDA-AuNPs/GC electrode possesses electrocatalytic activity for the oxidation of sulfite with high sensitivity and selectivity. Sulfite was quantified using amperometric measurement with the new sensor at +0.4V vs Ag/AgCl in conjunction with flow injection. The linear working range for the quantitation of sulfite was 2-200 mg L(-1) (r(2)=0.998) with a detection limit of 0.03 mg L(-1) (3σ of blank) and an estimated precision of 1.5%.The proposed method was successfully applied to the determination of sulfite in fruit juices and wines with a sample throughput of 23 samples per hour. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2006-01-01

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

  16. Flow-Injection Solid Phase Partial Least-Squares Spectrophotometric Simultaneous Determination of Iron, Nickel and Zinc

    Directory of Open Access Journals (Sweden)

    Teixeira Leonardo S. G.

    2002-01-01

    Full Text Available A PLS-2 multivariate calibration method has been developed for the simultaneous determination of iron, nickel and zinc in ternary mixtures by solid phase spectrophotometry associated with flow injection analysis. Fe(II, Ni(II and Zn(II form color complexes with 1-(2-thiazolylazo-2-naphthol (TAN, immobilized on a C18 bonded silica support, at pH 6.4. The proposed procedure is based on the different reaction/retention ratios of the studied ions on the solid support. Bilinear spectrophotometric data of the analytes, fixed in the solid support, were recorded in the 400-800 nm wavelength range as a function of time and a partial least squares (PLS-2 algorithm was used to predict results of synthetic samples. The calibration set employed was integrated by 8 ternary mixture standards and a blank solution. Mixtures containing 0.040 to 0.20 mg L-1, of each species, were successfully resolved, using 3 factors for each analyte and a restricted number of absorbance data obtained in the wavelength range from 560 to 650 nm.

  17. Spectrophotometric flow-injection determination of sulphite in white wines involving gas diffusion through a concentric tubular membrane

    Directory of Open Access Journals (Sweden)

    Melo Denise

    2003-01-01

    Full Text Available A flow-injection system is proposed for the spectrophotometric determination of sulphite in white wines. The method involves analyte conversion to SO2, gas diffusion through a Teflon® semi-permeable membrane, collection into an alkaline stream (pH 8, reaction with Malachite green (MG and monitoring at 620 nm. With a concentric tubular membrane, the system design was simplified. Influence of reagent concentrations, pH of donor and acceptor streams, temperature, timing, surfactant addition and presence of potential interfering species of the wine matrix were investigated. A pronounced (ca. 100% enhancement in sensitivity was noted by adding cetylpyridinium chloride (CPC. The proposed system is robust and baseline drift is not observed during 4 h operating periods. Only 400 muL of sample and 0.32 mg MG are required per determination. The system handles 30 samples per hour, yielding precise results (r.s.d. < 0.015 for 1.0 - 20.0 mg L-1 SO2 in agreement with those obtained by an alternative procedure.

  18. Fluoroscopically Guided Extraforaminal Cervical Nerve Root Blocks: Analysis of Epidural Flow of the Injectate with Respect to Needle Tip Position

    Science.gov (United States)

    Shipley, Kyle; Riew, K. Daniel; Gilula, Louis A.

    2013-01-01

    Study Design Retrospective evaluation of consecutively performed fluoroscopically guided cervical nerve root blocks. Objective To describe the incidence of injectate central epidural flow with respect to needle tip position during fluoroscopically guided extraforaminal cervical nerve root blocks (ECNRBs). Methods Between February 19, 2003 and June 11, 2003, 132 consecutive fluoroscopically guided ECNRBs performed with contrast media in the final injected material (injectate) were reviewed on 95 patients with average of 1.3 injections per patient. Fluoroscopic spot images documenting the procedure were obtained as part of standard quality assurance. An independent observer not directly involved in the procedures retrospectively reviewed the images, and the data were placed into a database. Image review was performed to determine optimal needle tip positioning for injectate epidural flow. Results Central epidural injectate flow was obtained in only 28.9% of injections with the needle tip lateral to midline of the lateral mass (zone 2). 83.8% of injectate went into epidural space when the needle tip was medial to midline of the lateral mass (zone 3). 100% of injectate flowed epidurally when the needle tip was medial to or at the medial cortex of the lateral mass (zone 4). There was no statistically significant difference with regards to central epidural flow and the needle tip position on lateral view. Conclusion To ensure central epidural flow with ECNRBs one must be prepared to pass the needle tip medial to midplane of the lateral mass or to medial cortex of the lateral mass. Approximately 16% of ECNRBs with needle tip medial to midline of the lateral mass did not flow into epidural space. One cannot claim a nerve block is an epidural block unless epidural flow of injectate is observed. PMID:24494176

  19. Polymeric microchip for the simultaneous determination of anions and cations by hydrodynamic injection using a dual-channel sequential injection microchip electrophoresis system.

    Science.gov (United States)

    Gaudry, Adam J; Nai, Yi Heng; Guijt, Rosanne M; Breadmore, Michael C

    2014-04-01

    A dual-channel sequential injection microchip capillary electrophoresis system with pressure-driven injection is demonstrated for simultaneous separations of anions and cations from a single sample. The poly(methyl methacrylate) (PMMA) microchips feature integral in-plane contactless conductivity detection electrodes. A novel, hydrodynamic "split-injection" method utilizes background electrolyte (BGE) sheathing to gate the sample flows, while control over the injection volume is achieved by balancing hydrodynamic resistances using external hydrodynamic resistors. Injection is realized by a unique flow-through interface, allowing for automated, continuous sampling for sequential injection analysis by microchip electrophoresis. The developed system was very robust, with individual microchips used for up to 2000 analyses with lifetimes limited by irreversible blockages of the microchannels. The unique dual-channel geometry was demonstrated by the simultaneous separation of three cations and three anions in individual microchannels in under 40 s with limits of detection (LODs) ranging from 1.5 to 24 μM. From a series of 100 sequential injections the %RSDs were determined for every fifth run, resulting in %RSDs for migration times that ranged from 0.3 to 0.7 (n = 20) and 2.3 to 4.5 for peak area (n = 20). This system offers low LODs and a high degree of reproducibility and robustness while the hydrodynamic injection eliminates electrokinetic bias during injection, making it attractive for a wide range of rapid, sensitive, and quantitative online analytical applications.

  20. Are Flow Injection-based Approaches Suitable for Automated Handling of Solid Samples?

    DEFF Research Database (Denmark)

    Miró, Manuel; Hansen, Elo Harald; Cerdà, Victor

    Flow-based approaches were originally conceived for liquid-phase analysis, implying that constituents in solid samples generally had to be transferred into the liquid state, via appropriate batch pretreatment procedures, prior to analysis. Yet, in recent years, much effort has been focused...... electrolytic or aqueous leaching, on-line dialysis/microdialysis, in-line filtration, and pervaporation-based procedures have been successfully implemented in continuous flow/flow injection systems. In this communication, the new generation of flow analysis, including sequential injection, multicommutated flow.......g., soils, sediments, sludges), and thus, ascertaining the potential mobility, bioavailability and eventual impact of anthropogenic elements on biota [2]. In this context, the principles of sequential injection-microcolumn extraction (SI-MCE) for dynamic fractionation are explained in detail along...

  1. Assessing preferential flow by simultaneously injecting nanoparticle and chemical tracers

    KAUST Repository

    Subramanian, S. K.; Li, Yan; Cathles, L. M.

    2013-01-01

    The exact manner in which preferential (e.g., much faster than average) flow occurs in the subsurface through small fractures or permeable connected pathways of other kinds is important to many processes but is difficult to determine, because most chemical tracers diffuse quickly enough from small flow channels that they appear to move more uniformly through the rock than they actually do. We show how preferential flow can be assessed by injecting 2 to 5 nm carbon particles (C-Dots) and an inert KBr chemical tracer at different flow rates into a permeable core channel that is surrounded by a less permeable matrix in laboratory apparatus of three different designs. When the KBr tracer has a long enough transit through the system to diffuse into the matrix, but the C-Dot tracer does not, the C-Dot tracer arrives first and the KBr tracer later, and the separation measures the degree of preferential flow. Tracer sequestration in the matrix can be estimated with a Peclet number, and this is useful for experiment design. A model is used to determine the best fitting core and matrix dispersion parameters and refine estimates of the core and matrix porosities. Almost the same parameter values explain all experiments. The methods demonstrated in the laboratory can be applied to field tests. If nanoparticles can be designed that do not stick while flowing through the subsurface, the methods presented here could be used to determine the degree of fracture control in natural environments, and this capability would have very wide ranging value and applicability.

  2. The effect of saturation on resin flow in injection pultrusion: a preliminary numerical study

    DEFF Research Database (Denmark)

    Spangenberg, Jon; Larsen, Martin; R. Rodríguez, Rosa

    . The implemented saturation and relative permeability curves are adopted from relationships presented in the literature. The results of the numerical model highlights the importance of accurately determining thesaturation curve when included in a numerical solver that is used to predict the resin flow in injection...

  3. An automated flow injection system for metal determination by flame atomic absorption spectrometry involving on-line fabric disk sorptive extraction technique.

    Science.gov (United States)

    Anthemidis, A; Kazantzi, V; Samanidou, V; Kabir, A; Furton, K G

    2016-08-15

    A novel flow injection-fabric disk sorptive extraction (FI-FDSE) system was developed for automated determination of trace metals. The platform was based on a minicolumn packed with sol-gel coated fabric media in the form of disks, incorporated into an on-line solid-phase extraction system, coupled with flame atomic absorption spectrometry (FAAS). This configuration provides minor backpressure, resulting in high loading flow rates and shorter analytical cycles. The potentials of this technique were demonstrated for trace lead and cadmium determination in environmental water samples. The applicability of different sol-gel coated FPSE media was investigated. The on-line formed complex of metal with ammonium pyrrolidine dithiocarbamate (APDC) was retained onto the fabric surface and methyl isobutyl ketone (MIBK) was used to elute the analytes prior to atomization. For 90s preconcentration time, enrichment factors of 140 and 38 and detection limits (3σ) of 1.8 and 0.4μgL(-1) were achieved for lead and cadmium determination, respectively, with a sampling frequency of 30h(-1). The accuracy of the proposed method was estimated by analyzing standard reference materials and spiked water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Jet flow analysis of liquid poison injection in a CANDU reactor using source term

    International Nuclear Information System (INIS)

    Chae, Kyung Myung; Choi, Hang Bok; Rhee, Bo Wook

    2001-01-01

    For the performance analysis of Canadian deuterium uranium (CANDU) reactor shutdown system number 2 (SDS2), a computational fluid dynamics model of poison jet flow has been developed to estimate the flow field and poison concentration formed inside the CANDU reactor calandria. As the ratio of calandria shell radius over injection nozzle hole diameter is so large (1055), it is impractical to develop a full-size model encompassing the whole calandria shell. In order to reduce the model to a manageable size, a quarter of one-pitch length segment of the shell was modeled using symmetric nature of the jet; and the injected jet was treated as a source term to avoid the modeling difficulty caused by the big difference of the hole sizes. For the analysis of an actual CANDU-6 SDS2 poison injection, the grid structure was determined based on the results of two-dimensional real- and source-jet simulations. The maximum injection velocity of the liquid poison is 27.8 m/s and the mass fraction of the poison is 8000 ppm (mg/kg). The simulation results have shown well-established jet flow field. In general, the jet develops narrowly at first but stretches rapidly. Then, the flow recirculates a little in r-x plane, while it recirculates largely in r-θ plane. As the time goes on, the adjacent jets contact each other and form a wavy front such that the whole jet develops in a plate form. his study has shown that the source term model can be effectively used for the analysis of the poison injection and the simulation result of the CANDU reactor is consistent with the model currently being used for the safety analysis. In the future, it is strongly recommended to analyze the transient (from helium tank to injection nozzle hole) of the poison injection by applying Bernoulli equation with real boundary conditions

  5. Retro-review of flow injection analysis

    DEFF Research Database (Denmark)

    Ruzicka, Jaromir; Hansen, Elo Harald

    2008-01-01

    It is indeed unusual for authors to review their own monograph – J. Ruzicka, E.H. Hansen, Flow Injection Analysis, 2nd Edition, Wiley, Chichester, West Sussex, UK, 1988. – and even more so if the book was published 20 years ago. Yet such an exercise might yield a perspective on the progress of an...

  6. Cost-effective flow injection amperometric system with metal nanoparticle loaded carbon nanotube modified screen printed carbon electrode for sensitive determination of hydrogen peroxide.

    Science.gov (United States)

    Reanpang, Preeyaporn; Themsirimongkon, Suwaphid; Saipanya, Surin; Chailapakul, Orawon; Jakmunee, Jaroon

    2015-11-01

    Various metal nanoparticles (NPs) decorated on carbon nanotube (CNT) was modified on the home-made screen printed carbon electrode (SPCE) in order to enhances sensitivity of hydrogen peroxide (H2O2) determination. The simple casting method was used for the electrode modification. The monometallic and bimetallic NPs modified electrodes were investigated for their electrochemical properties for H2O2 reduction. The Pd-CNT/SPCE is appropriated to measure the H2O2 reduction at a potential of -0.3 V, then this modified electrode was incorporated with a home-made flow through cell and applied in a simple flow injection amperometry (FI-Amp). Some parameters influencing the resulted modified electrode and the FI-Amp system were studied. The proposed detection system was able to detect H2O2 in the range of 0.1-1.0 mM, with detection limit of 20 µM. Relative standard deviation for 100 replicated injections of 0.6 mM H2O2 was 2.3%. The reproducibility of 6 electrodes preparing in 3 different lots was 8.2%. It was demonstrated for determination of H2O2 in disinfectant, hair colorant and milk samples. Recoveries in the range of 90-109% were observed. The developed system provided high stability, good repeatability, high sample throughput and low reagent consumption. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. FLOW INJECTION ANALYSIS SYSTEM COUPLED WITH ICP-EOS FOR DETERMINATION OF SOME METALLIC ELEMENTS IN DRINKING WATER

    Directory of Open Access Journals (Sweden)

    Cristina Dinu

    2009-06-01

    Full Text Available The European Drinking Water Directive (98/83/EC, transposed in Romanian Legislation as Low 458/2002, amended by Low 311/2004, imposes the limit of concentration for metallic elements in water intended for human consumption. The toxic metals arsenic and selenium are among these elements and the limit value is 10 μg/L. In the paper there are presented the working conditions for determination of As and Se from drinking water using modern techniques based on the fl ow injection-hydride generation with the inductively coupled plasma atomic emission spectrometry (FIAS-ICP-EOS. The analyses were performed on Optima 5300 DV Perkin Elmer equipment with FIAS 400 Flow Injection System, Perkin Elmer type. For the hydride generation two types of solution were used: 10% (v/v HCl as a carrier solution and 0.2 % NaBH4 in 0.05%NaOH solution as a reducing agent [1]. The treatment step of the samples and standard solutions consisted in reducing with mixed solutions of KI and ascorbic acid in acidic condition (HCl for As and only with HCl and high temperature for Se [2,3]. The paper contains the characteristic parameters of the methods, such as: low detection limit, quantifi cation limit, repeatability, precision, recovery, which were evaluated using Certifi ed Reference Materials for each element.

  8. Trace and ultratrace analysis methods for the determination of phosphorus by flow-injection techniques.

    Science.gov (United States)

    Motomizu, Shoji; Li, Zhen-Hai

    2005-04-15

    Trace (phosphorus determination by flow-injection analysis are reviewed. Most of the methods cited in this review are fundamentally based on the reaction of orthophosphate with molybdate to form heteropoly acids, such as molybdenum yellow and molybdenum blue, and some of the methods are based on the formation of such secondary reactions as ion associates and their aggregates with bulky cations, such as cationic dyes and quaternary ammonium ions. The heteropoly acids themselves can be measured by spectrophotometry, and the ion associate formed with a cationic dye, Malachite Green (MG), can be measured based on the coloration of MG. Light scattering detection methods can be used for measuring the aggregates of ion associates formed with bulky cations. Highly sensitive detection of phosphorus can be accomplished by fluorophotometry; Rhodamine B (RB) and its analogues react with molybdophosphate to form ion associates, which shows fluorescence quenching of RB: LOD is about 5 nM. The detection method based on the chemiluminescence of luminal oxidized with molybdophosphoric acids is probably the most sensitive of all the detection methods reported so far: LOD of the method is as low as 1nM. The LOD of the molybdenum blue method can be improved by using a liquid core waveguide: LOD is 0.5 nM.

  9. Determination of boron in natural water and products derived from grape using an automated flow injection analysis system with piezoelectric detection

    International Nuclear Information System (INIS)

    Jesus, Dosil P. de; Saito, Renata M.; Lago, Claudimir L. do

    2004-01-01

    An automated flow injection analysis system with piezoelectric detection is proposed as a sensitive and selective method for boron. The detector is an electrode-separated piezoelectric quartz crystal coated with N-methyl-D-glucamine-modified poly(epichlorohydrin). The film ability to retain boron allows the adjustment of the linear dynamic range and the sensitivity by varying the injected sample volume. In the present work, the sample volumes were varied from 0.5 to 5.0 mL. Among several ionic species, germanate is the only one that can interfere in the method. Nevertheless, it can be eliminated by addition of sulfide to the sample. The method was successfully applied to the determination of boron concentration in samples of natural water (from 1.71 to 309 μL -1 ) and products derived from grape juice (from 2.06 to 6.21 mg L -1 ). A pretreatment with hydrogen peroxide in alkaline medium was required due to the great amount of sugars in the grape products (author)

  10. Flow injection on-line preconcentration of low levels of Cr(VI) with detection by ETAAS

    DEFF Research Database (Denmark)

    Som-aum, Waraporn; Liawruangrath, Saisunee; Hansen, Elo Harald

    2002-01-01

    A flow injection (FI) on-line sorption preconcentration procedure utilizing a packed column reactor and combined with electrothermal atomic absorption spectrometry (ETAAS) is proposed for the determination of low levels of Cr(VI) in water samples. Polytetrafluoroethylene (PTFE) beads packed in a ...

  11. Trends and perspectives of flow injection/sequential injection on-line sample-pretreatment schemes coupled to ETAAS

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2005-01-01

    Flow injection (FI) analysis, the first generation of this technique, became in the 1990s supplemented by its second generation, sequential injection (SI), and most recently by the third generation (i.e.,Lab-on-Valve). The dominant role played by FI in automatic, on-line, sample pretreatments in ...

  12. Determination of uranium in natural waters and high-purity aluminum by flow-injection on-line preconcentration and ICP-MS detection

    International Nuclear Information System (INIS)

    Seki, Tatsuya; Oguma, Koichi

    2004-01-01

    A flow injection method has been developed for the determination of uranium is natural waters and high-purity aluminum by use of on-line preconcentration on a U/TEVA TM column and ICP-MS detection. The sample solution prepared as a nitric acid solution in 3 mol l -1 was passed through the U/TEVA TM column to collect uranium and uranium adsorbed was eluted with 0.1 mol l -1 nitric acid. The effluent was introduced directly into the nebulizer of the ICP-MS and 238 U was measured. The detection limit, calculated as 3-times the standard deviation of the background noise, was 3pg and the sample throughput was about 10 per hour. The proposed method was successfully applied to the determination of uranium in river-water reference materials, a seawater reference material and high-purity aluminum reference materials. (author)

  13. Flow injection preconcentration system using a new functionalized resin for determination of cadmium and nickel in tobacco samples

    International Nuclear Information System (INIS)

    Lemos, Valfredo Azevedo; Novaes, Cleber Galvao; Lima, Adriana da Silva; Vieira, Daniel Rodrigues

    2008-01-01

    A solid-phase extraction method combined with flow injection (FI) on-line flame atomic absorption spectrometry (FAAS) for the determination of cadmium and nickel in tobacco samples is presented. The 2-aminothiophenol functionalized Amberlite XAD-4 (AT-XAD) resin was synthesized by covalent coupling of the ligand with the copolymer through a methylene group. A minicolumn packed with AT-XAD was connected into the automated on-line preconcentration system. Elution of metal ions from minicolumn can be made with 0.50 mol L -1 hydrochloric acid solution. With a consumption of 21.0 mL of sample solution, detection limits (3 s) of 0.3 (Cd) and 0.8 μg L -1 (Ni) were achieved at a sample throughput of 18 h -1 . Enrichment factors (EF) of 99 (cadmium) and 43 (nickel) were obtained compared with the slope of the linear portion of the calibration curves before and after preconcentration. The contents of Cd and Ni in a certified reference material (NIST 1570a, spinach leaves) determined by the present method was in good agreement with the certified value. The developed procedure was also successfully applied to the determination of Cd and Ni in local tobacco samples

  14. A simple and selective spectrophotometric flow injection determination of trace amounts of ruthenium by catalytic oxidation of safranin-O

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, Behzad [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-84111 (Iran, Islamic Republic of)], E-mail: rezaei@cc.iut.ac.ir; Keyvanfard, Mohsen [Faculty of Science, Majlesi Campus, Islamic Azad University, Isfahan (Iran, Islamic Republic of)

    2008-03-01

    In this work, a simple, selective and rapid flow injection method has been developed for determination of ruthenium. The method is based on its catalytic effect on the oxidation of safranin-O by metaperiodate. The reaction was monitored spectrophotometrically by measuring safranin-O absorbance at {lambda}{sub max} = 521. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine ruthenium in the ranges of 0.4-20.0 ng/mL ({delta}A = 0.2819C{sub Ru} + 1.1840) and 20.0-100.0 ng/mL ({delta}A = 0.0984C{sub Ru} + 7.9391) with a detection limit of 0.095 ng/mL and a sample rate of 30 {+-} 5 samples/h. Relative standard deviation for the five replicate measurements was less than 1.84%. The proposed method has been successfully applied for analysis of ultra trace amounts of ruthenium in real samples.

  15. A simple and selective spectrophotometric flow injection determination of trace amounts of ruthenium by catalytic oxidation of safranin-O

    International Nuclear Information System (INIS)

    Rezaei, Behzad; Keyvanfard, Mohsen

    2008-01-01

    In this work, a simple, selective and rapid flow injection method has been developed for determination of ruthenium. The method is based on its catalytic effect on the oxidation of safranin-O by metaperiodate. The reaction was monitored spectrophotometrically by measuring safranin-O absorbance at λ max = 521. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine ruthenium in the ranges of 0.4-20.0 ng/mL (ΔA = 0.2819C Ru + 1.1840) and 20.0-100.0 ng/mL (ΔA = 0.0984C Ru + 7.9391) with a detection limit of 0.095 ng/mL and a sample rate of 30 ± 5 samples/h. Relative standard deviation for the five replicate measurements was less than 1.84%. The proposed method has been successfully applied for analysis of ultra trace amounts of ruthenium in real samples

  16. Determination of hydrogen peroxide in water by chemiluminescence detection, (1). Flow injection type hydrogen peroxide detection system

    International Nuclear Information System (INIS)

    Yamashiro, Naoya; Uchida, Shunsuke; Satoh, Yoshiyuki; Morishima, Yusuke; Yokoyama, Hiroaki; Satoh, Tomonori; Sugama, Junichi; Yamada, Rie

    2004-01-01

    A flow injection type hydrogen peroxide detection system with a sub-ppb detection limit has been developed to determine hydrogen peroxide concentration in water sampled from a high temperature, high pressure hydrogen peroxide water loop. The hydrogen peroxide detector is based on luminol chemiluminescence spectroscopy. A small amount of sample water (20 μl) is mixed with a reagent mixture, an aqueous solution of luminol and Co 2+ catalyst, in a mixing cell which is installed just upstream from the detection cell. The optimum values for pH and the concentrations of luminol and Co 2+ ion have been determined to ensure a lower detectable limit and a higher reproducibility. The photocurrent detected by the detection system is expressed by a linear function of the hydrogen peroxide concentration in the region of lower concentration ([H 2 O 2 ] 2 O 2 ] in the region of higher concentration ([H 2 O 2 ] > 10 ppb). The luminous intensity of luminol chemiluminescence is the highest when pH of the reagent mixture is 11.0. Optimization of the major parameters gives the lowest detectable limit of 0.3 ppb. (author)

  17. Preconcentration and determination of iron and copper in spice samples by cloud point extraction and flow injection flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Cigdem Arpa, E-mail: carpa@hacettepe.edu.tr [Hacettepe University, Chemistry Department, 06800 Beytepe, Ankara (Turkey); Tokgoez, Ilknur; Bektas, Sema [Hacettepe University, Chemistry Department, 06800 Beytepe, Ankara (Turkey)

    2010-09-15

    A flow injection (FI) cloud point extraction (CPE) method for the determination of iron and copper by flame atomic absorption spectrometer (FAAS) has been improved. The analytes were complexed with 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR) and octylphenoxypolyethoxyethanol (Triton X-114) was added as a surfactant. The micellar solution was heated above 50 {sup o}C and loaded through a column packed with cotton for phase separation. Then the surfactant-rich phase was eluted using 0.05 mol L{sup -1} H{sub 2}SO{sub 4} and the analytes were determined by FAAS. Chemical and flow variables influencing the instrumental and extraction conditions were optimized. Under optimized conditions for 25 mL of preconcentrated solution, the enrichment factors were 98 and 69, the limits of detection (3s) were 0.7 and 0.3 ng mL{sup -1}, the limits of quantification (10s) were 2.2 and 1.0 ng mL{sup -1} for iron and copper, respectively. The relative standard deviation (RSD) for ten replicate measurements of 10 ng mL{sup -1} iron and copper were 2.1% and 1.8%, respectively. The proposed method was successfully applied to determination of iron and copper in spice samples.

  18. A microfabricated electroosmotic pump coupled to a gas-diffusion microchip for flow injection analysis of ammonia

    International Nuclear Information System (INIS)

    Zhu, Zaifang; Lu, Joann J.; Liu, Shaorong; Almeida, M. Inês G. S.; Kolev, Spas D.; Pu, Qiaosheng

    2015-01-01

    We have microfabricated two functional components toward developing a microchip flow injection analysis (FIA) system, i.e., an open-channel electroosmotic pump and a gas-diffusion chip, consisting of two microfabricated glass wafers and a porous polytetrafluoroethylene membrane. This is the first application of gas-diffusion separation in a microchip FIA system. To demonstrate the feasibility of using these two components for performing gas-diffusion FIA, we have incorporated them together with a regular FIA injection valve and a capillary electrophoresis absorbance detector in a flow injection system for determination of ammonia in environmental water samples. This system has a limit of detection of 0.10 mg L −1 NH 3 , with a good repeatability (relative standard deviation of less than 5 % for 4.0 mg L −1 NH 3 ). Parameters affecting its performance are also discussed. (author)

  19. Lanthanides determination in red wine using ultrasound assisted extraction, flow injection, aerosol desolvation and ICP-MS

    International Nuclear Information System (INIS)

    Bentlin, Fabrina R.S.; Santos, Clarissa M.M. dos; Flores, Érico M.M.; Pozebon, Dirce

    2012-01-01

    Highlights: ► Ultrasound was investigated and applied for red wine samples preparation. ► Aliquots of 50 μL of sample were nebulized and transported to plasma. ► FI and pneumatic nebulization/aerosol desolvation were used. ► LODs of the ICP-MS method for lanthanides determination were at ng L −1 level. ► Lanthanides concentration allowed red wines classification. - Abstract: This paper deals with the determination of the fourteen naturally occurring elements of the lanthanide series in red wine. Ultrasound (US) was used for sample preparation prior lanthanides determination using ICP-MS. Flow injection (FI) and pneumatic nebulization/aerosol desolvation were used for nebulization of aliquots of 50 μL of sample and its subsequent transportation to plasma. Sample preparation procedures, matrix interference and time of sonication were evaluated. Better results for lanthanides in red wine were obtained by sonication with US probe for 90 s and sample 10-fold diluted. The limits of detection of La, Ce, Nd, Sm, Gd, Pr, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb were 6.57, 10.8, 9.97, 9.38, 2.71, 1.29, 1.22, 0.52, 2.35, 0.96, 2.30, 0.45, 0.24 and 1.35 ng L −1 , respectively. Red wines of different varieties from three countries of South America were discriminated according to the country of origin by means of multivariate analysis of lanthanides concentration.

  20. An investigation of flow properties of metal matrix composites suspensions for injection molding

    International Nuclear Information System (INIS)

    Ahmad, F.; Bevis, M.J.

    1997-01-01

    Flow properties of metal matrix composites suspensions have significant effects on the fibre orientation during mould filling. The results presented in this paper relate to the flow properties of aluminium powder and glass fibres compounded into a sacrificial thermoplastics binder. For this purpose, a range of aluminium compounds and aluminium composite suspensions were investigated over a wide shear rate range expected to occur during injection mould process. Aluminium composites wee prepared by substituting glass fibres for aluminium in aluminium compound. Aluminium composite containing a maximum critical volume fraction of fibres which did not exhibit an increase n viscosity was determined. The effect of temperature on the flow behaviour of aluminium composite was also investigated. (author)

  1. Flow injection chemiluminescence determination of loxoprofen and naproxen with the acidic permanganate-sulfite system

    Directory of Open Access Journals (Sweden)

    Li-Juan Wang

    2011-02-01

    Full Text Available A novel flow injection chemiluminescence (CL method for the determination of loxoprofen and naproxen was proposed based on the CL system of KMnO4, and Na2SO3 in acid media. The CL intensity of KMnO4-Na2SO3 was greatly enhaneed in the presence of loxoprofen and naproxen. The mechanism of the CL reaction was studied by the kinetic proecss and UV-vis absorption and the conditions were optimized. Under optimized conditions, the CL intensity was linear with loxoprofen and naproxen concentration in the range of 7.0 × 10−8 – 1.0 × 10−5 g/mL and 2.0 × 10−7 – 4.0 × 10−6 g/mL with the detection limit of 2.0 × 10−8 g/mL and 3.0 × 10−8 g/mL (S/N = 3, respectively. Thc relative standard deviations were 2.39% and 1.37% for 5.0 × 10−7 g/mL naproxen and 5.0 × 10−7 g/mL loxoprofen (n = 10, respectively. The proposed method was satisfactorily applied to thc determination of loxoprofen and naproxen in pharmaceutical preparations. Keywords: chemiluminescence, KMnO4, loxoprofen, naproxen

  2. Flow injection chemiluminescence determination of lercanidipine based on N-chlorosuccinimide-eosin Y post-chemiluminescence reaction.

    Science.gov (United States)

    Wang, Guowei; Zhao, Fang; Gao, Ying

    2014-12-01

    A novel post-chemiluminescence (PCL) reaction was discovered when lercanidipine was injected into the CL reaction mixture of N-chlorosuccinimide with alkaline eosin Y in the presence of cetyltrimethylammonium bromide (CTAB), where eosin Y was used as the CL reagent and CTAB as the surfactant. Based on this observation, a simple and highly sensitive PCL method combined with a flow injection (FI) technique was developed for the assay of lercanidipine. Under optimum conditions, the CL signal was linearly related to the concentration of lercanidipine in the range 7.0 × 10(-10) to 3.0 × 10(-6)  g/mL with a detection limit of 2.3 × 10(-10) g/mL (3σ). The relative standard deviation (RSD) was 2.1% for 1.0 × 10(-8) g/mL lercanidipine (n = 13). The proposed method had been applied to the estimation of lercanidipine in tablets and human serum samples with satisfactory results. The possible CL mechanism is also discussed briefly. Copyright © 2014 John Wiley & Sons, Ltd.

  3. Sequential determination of multi-nutrient elements in natural water samples with a reverse flow injection system.

    Science.gov (United States)

    Lin, Kunning; Ma, Jian; Yuan, Dongxing; Feng, Sichao; Su, Haitao; Huang, Yongming; Shangguan, Qipei

    2017-05-15

    An integrated system was developed for automatic and sequential determination of NO 2 - , NO 3 - , PO 4 3- , Fe 2+ , Fe 3+ and Mn 2+ in natural waters based on reverse flow injection analysis combined with spectrophotometric detection. The system operation was controlled by a single chip microcomputer and laboratory-programmed software written in LabVIEW. The experimental parameters for each nutrient element analysis were optimized based on a univariate experimental design, and interferences from common ions were evaluated. The upper limits of the linear range (along with detection limit, µmolL -1 ) of the proposed method was 20 (0.03), 200 (0.7), 12 (0.3), 5 (0.03), 5 (0.03), 9 (0.2) µmolL -1 , for NO 2 - , NO 3 - , PO 4 3- , Fe 2+ , Fe 3+ and Mn 2+ , respectively. The relative standard deviations were below 5% (n=9-13) and the recoveries varied from 88.0±1.0% to 104.5±1.0% for spiked water samples. The sample throughput was about 20h -1 . This system has been successfully applied for the determination of multi-nutrient elements in different kinds of water samples and showed good agreement with reference methods (slope 1.0260±0.0043, R 2 =0.9991, n=50). Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Flow injection determination of hydrogen peroxide using catalytic effect of cobalt(II) ion on a dye formation reaction.

    Science.gov (United States)

    Kurihara, Makoto; Muramatsu, Miyuki; Yamada, Mari; Kitamura, Naoya

    2012-07-15

    A novel flow injection photometric method was developed for the determination of hydrogen peroxide in rainwater. This method is based on a cobalt(II)-catalyzed oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethoxyaniline (DAOS) as a modified Trinder's reagent to produce intensely colored dye (λ(max)=530nm) in the presence of hydrogen peroxide at pH 8.4. In this method, 1,2-dihydroxy-3,5-benzenedisulfonic acid (Tiron) acted as an activator for the cobalt(II)-catalyzed reaction and effectively increased the peak height for hydrogen peroxide. The linear calibration graphs were obtained in the hydrogen peroxide concentration range 5×10(-8) to 2.2×10(-6)mol dm(-3) at a sampling rate of 20h(-1). The relative standard deviations for ten determinations of 2.2×10(-6) and 2×10(-7)mol dm(-3) hydrogen peroxide were 1.1% and 3.7%, respectively. The proposed method was successfully applied to the determination of hydrogen peroxide in rainwater samples and the analytical results agreed fairly well with the results obtained by different two reference methods; peroxidase method and hydrogen peroxide electrode method. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Reverse flow injection spectrophotometric determination of ciprofloxacin in pharmaceuticals using iron from soil as a green reagent

    Science.gov (United States)

    Palamy, Sysay; Ruengsitagoon, Wirat

    2018-02-01

    A novel reverse flow injection spectrophotometric method for the determination of ciprofloxacin was successfully combined with the on-line introduction of an iron solution extracted from soil as green reagent. The assay was optimized by a univariate method to select the optimum conditions for the highest absorbance and highest stability of the complex. Beer-Lambert's law (λmax = 440 nm) is obeyed in the range 0.5-50 μg mL- 1 with a correlation coefficient (r2) of 0.9976 and 0.9996 using soil as green reagent from Khon Kaen, Thailand and Vientiane, Laos, respectively. The average percentage recoveries were in the range of 98.55-102.14% and the precision was in the range of 0.80-1.73%. The limit of detection and the limit of quantitation were 0.20 and 0.69 μg mL- 1, respectively, with a sampling rate of over 46 samples h- 1. The method was successfully applied to the determination of ciprofloxacin in commercial pharmaceutical formulations. The results were in good agreement with those obtained by the reference HPLC method using a t-test at 95% of confidence level for comparison. This method is suitable for laboratories looking for alternative analytical methods using green reagents.

  6. Flow injection determination of diclofenac sodium based on its sensitizing effect on the chemiluminescent reaction of acidic potassium permanganate-formaldehyde.

    Science.gov (United States)

    Song, Jingjing; Sun, Pulv; Ji, Zhongling; Li, Jianguo

    2015-02-01

    A sensitive and simple chemiluminescent (CL) method for the determination of diclofenac sodium has been developed by combining the flow injection technique and its sensitizing effect on the weak CL reaction between formaldehyde and acidic potassium permanganate. A calibration curve is constructed for diclofenac sodium under optimized experimental parameters over the range 0.040-5.0 µg/mL and the limit of detection is 0.020 µg/mL (3σ). The inter-assay relative standard deviation for 0.040 µg/mL diclofenac sodium (n = 11) is 2.0%. This method is rapid, sensitive, simple, and shows good selectivity and reproducibility. The proposed method has been successfully applied to the determination of the studied diclofenac sodium in pharmaceutical preparations with satisfactory results. Furthermore, the possible mechanism for the CL reaction has been discussed in detail on the basis of UV and CL spectra. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Lanthanides determination in red wine using ultrasound assisted extraction, flow injection, aerosol desolvation and ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Bentlin, Fabrina R.S. [Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501.970 Porto Alegre, RS (Brazil); Santos, Clarissa M.M. dos; Flores, Erico M.M. [Departamento de Quimica Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Pozebon, Dirce, E-mail: dircepoz@iq.ufrgs.br [Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501.970 Porto Alegre, RS (Brazil)

    2012-01-13

    Highlights: Black-Right-Pointing-Pointer Ultrasound was investigated and applied for red wine samples preparation. Black-Right-Pointing-Pointer Aliquots of 50 {mu}L of sample were nebulized and transported to plasma. Black-Right-Pointing-Pointer FI and pneumatic nebulization/aerosol desolvation were used. Black-Right-Pointing-Pointer LODs of the ICP-MS method for lanthanides determination were at ng L{sup -1} level. Black-Right-Pointing-Pointer Lanthanides concentration allowed red wines classification. - Abstract: This paper deals with the determination of the fourteen naturally occurring elements of the lanthanide series in red wine. Ultrasound (US) was used for sample preparation prior lanthanides determination using ICP-MS. Flow injection (FI) and pneumatic nebulization/aerosol desolvation were used for nebulization of aliquots of 50 {mu}L of sample and its subsequent transportation to plasma. Sample preparation procedures, matrix interference and time of sonication were evaluated. Better results for lanthanides in red wine were obtained by sonication with US probe for 90 s and sample 10-fold diluted. The limits of detection of La, Ce, Nd, Sm, Gd, Pr, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb were 6.57, 10.8, 9.97, 9.38, 2.71, 1.29, 1.22, 0.52, 2.35, 0.96, 2.30, 0.45, 0.24 and 1.35 ng L{sup -1}, respectively. Red wines of different varieties from three countries of South America were discriminated according to the country of origin by means of multivariate analysis of lanthanides concentration.

  8. Flow Injection and Atomic Absorption Spectrometry (FI-AAS) -

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    1996-01-01

    One of the advantages of the flow injection (FI) concept is that it is compatible with virtually all detection techniques. Being a versatile vehicle for enhancing the performance of the individual detection devices, the most spectacular results have possibly been obtained in conjunction with atomic...... the point of sample injection/introduction to the point of detection. Hence, in FI-fAAS this feature allows not only to obtain improved repeatability but also improved accuracy, and because the wash to sample ratio is high it permits the handling of samples with elevated salt contents - which...

  9. Interaction of Liquid Film Flow of Direct Vessel Injection Under the Cross Directional Gas Flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-sol; Lee, Jae-young [Handong Global University, Pohang (Korea, Republic of); Euh, Dong-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In order to obtain a proper scaling law of the flow, local information of the flow was investigated experimentally and also numerically. A series of experiments were conducted in the 1/20 modified linear scaled plate type test rig to analyze a liquid film from ECC water injection through the DVI nozzle to the downcomer wall. The present study investigates liquid film flow generated in a downcomer of direct vessel injection (DVI) system which is employed as an emergency core cooling (ECC) system during a loss of coolant accident in the Korea nuclear power plant APR1400. During the late reflooding, complicated multi-phase flow phenomena including the wavy film flow, film breakup, entrainment, liquid film shift due to interfacial drag and gas jet impingement occur. A confocal chromatic sensor was used to measure the local instantaneous liquid film thickness and a hydraulic jump in the film flow and boundaries of the film flow. It was found that CFD analysis results without surface tension model showed some difference with the data in surface tension dominated flow region. For the interaction between a liquid film and gas shear flow, CFD results make a good agreement with the real liquid film dynamics in the case of low film Reynolds number or low Weber number flow. In the 1/20 scaled plate type experiment and simulation, the deformed spreading profile results seem to accord with each other at the relatively low We and Re regime.

  10. The determination of levofloxacin by flow injection analysis using UV detection, potentiometry, and conductometry in pharmaceutical preparations.

    Science.gov (United States)

    Altiokka, G; Atkosar, Z; Can, N O

    2002-10-15

    A flow injection analysis (FIA) using UV detection, potentiometry and conductometry for levofloxacin (LVF) are described in this study. The best solvent system was found to consist of 0.2 M acetate buffer at pH 3 having 10% MeOH. A flow rate of 1 ml min(-1) was pumped and active material was detected at 288 nm. The detection limit (LOD) and limit of quantification (LOQ) for FIA were calculated to be 3 x 10(-7) M (S/N = 3) and 1 x 10(-7) M (S/N = 10), respectively. In the analysis of tablets, the RSD values were found to be 0.83, 0.98 and 0.99 for FIA, potentiometric and conductometric methods, respectively. Copyright 2002 Elsevier Science B.V.

  11. Flow-injection analysis of nitrate by reduction to nitrite and gas-phase molecular absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Haghighi, B.; Tavassoli, A. [Dept. of Chemistry, Inst. for Advanced Studies in Basic Sciences, Zanjan (Iran)

    2001-12-01

    Two flow-injection manifolds have been investigated for the determination of nitrate. These manifolds are based on the reduction of nitrate to nitrite and determination of nitrite by gas-phase molecular absorption spectrophotometry. Nitrate sample solution (300 {mu}L) which is injected to the flow line, is reduced to nitrite by reaction with hydrazine or passage through the on-line copperized cadmium (Cd-Cu) reduction column. The nitrite produced reacts with a stream of hydrochloric acid and the evolved gases are purged into the stream of O{sub 2}carrier gas. The gaseous phase is separated from the liquid phase using a gas-liquid separator and then swept into a flow-through cell which has been positioned in the cell compartment of an UV-visible spectrophotometer. The absorbance of the gaseous phase is measured at 204.7 nm. A linear relationship was obtained between the intensity of absorption signals and concentration of nitrate when Cd-Cu reduction method was used, but a logarithmic relationship was obtained when the hydrazine reduction method was used. By use of the Cd-Cu reduction method, up to 330 {mu}g of nitrate was determined. The limit of detection was 2.97 {mu}g nitrate and the relative standard deviations for the determination of 12.0, 30.0 and 150 {mu}g nitrate were 3.32, 3.87 and 3.6%, respectively. Maximum sampling rate was approximately 30 samples per hour. The Cd-Cu reduction method was applied to the determination of nitrate and the simultaneous determination of nitrate and nitrite in meat products, vegetables, urine, and a water sample. (orig.)

  12. Fabrication of an Amperometric Flow-Injection Microfluidic Biosensor Based on Laccase for In Situ Determination of Phenolic Compounds

    Directory of Open Access Journals (Sweden)

    Juan C. Gonzalez-Rivera

    2015-01-01

    Full Text Available We aim to develop an in situ microfluidic biosensor based on laccase from Trametes pubescens with flow-injection and amperometry as the transducer method. The enzyme was directly immobilized by potential step chronoamperometry, and the immobilization was studied using cyclic voltammetry and electrochemical impedance spectroscopy. The electrode response by amperometry was probed using ABTS and syringaldazine. A shift of interfacial electron transfer resistance and the electron transfer rate constant from 18.1 kΩ to 3.9 MΩ and 4.6 × 10−2 cm s−1 to 2.1 × 10−4 cm s−1, respectively, evidenced that laccase was immobilized on the electrode by the proposed method. We established the optimum operating conditions of temperature (55°C, pH (4.5, injection flow rate (200 µL min−1, and applied potential (0.4 V. Finally, the microfluidic biosensor showed better lower limit of detection (0.149 µM and sensitivity (0.2341 nA µM−1 for ABTS than previous laccase-based biosensors and the in situ operation capacity.

  13. Multicommuted flow injection method for fast photometric determination of phenolic compounds in commercial virgin olive oil samples.

    Science.gov (United States)

    Lara-Ortega, Felipe J; Sainz-Gonzalo, Francisco J; Gilbert-López, Bienvenida; García-Reyes, Juan F; Molina-Díaz, Antonio

    2016-01-15

    A multicommuted flow injection method has been developed for the determination of phenolic species in virgin olive oil samples. The method is based on the inhibitory effect of antioxidants on a stable and colored radical cation formation from the colorless compound N,N-dimethyl-p-phenylenediamine (DMPD(•+)) in acidic medium in the presence of Fe(III) as oxidant. The signal inhibition by phenolic species and other antioxidants is proportional to their concentration in the olive oil sample. Absorbance was recorded at 515nm by means of a modular fiber optic spectrometer. Oleuropein was used as the standard for phenols determination and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox) was the reference standard used for total antioxidant content calculation. Linear response was observed within the range of 250-1000mg/kg oleuropein, which was in accordance with phenolic contents observed in commercial extra virgin olive oil in the present study. Fast and low-volume liquid-liquid extraction of the samples using 60% MeOH was made previous to their insertion in the flow multicommuted system. The five three-way solenoid valves used for multicommuted liquid handling were controlled by a homemade electronic interface and Java-written software. The proposed approach was applied to different commercial extra virgin olive oil samples and the results were consistent with those obtained by the Folin Ciocalteu (FC) method. Total time for the sample preparation and the analysis required in the present approach can be drastically reduced: the throughput of the present analysis is 8 samples/h in contrast to 1sample/h of the conventional FC method. The present method is easy to implement in routine analysis and can be regarded as a feasible alternative to FC method. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Radiometric flow injection analysis with an ASIA (Ismatec) analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Myint, U; Win, N; San, K; Han, B; Myoe, K M [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

    1994-07-01

    Radiometric Flow Injection Analysis of a radioactive ([sup 131]I) sample is described. For analysis an ASIA (Ismatec) analyzer with a NaI(Tl) scintillation detector was used. (author) 5 refs.; 3 figs.

  15. Channel flow induced by wall injection of fluid and particles; Ecoulement induit par injection parietale de fluide et de particules dans un conduit

    Energy Technology Data Exchange (ETDEWEB)

    Feraille, Th.; Casalis, G. [Aerodynamics and Energetics Modeling Dept., 31 - Toulouse (France)

    2003-12-01

    The Taylor flow is the laminar single phase flow induced by gas injection through porous walls, and is assumed to represent the flow inside solid propellant motors. Such a flow is intrinsically unstable, and the generated instabilities are probably responsible for the thrust oscillations observed in the aforesaid motors. However particles are embedded in the propellants usually used, and are released in the fluid by the lateral walls during the combustion, so that there are two heterogeneous phases in the flow. The purpose of this paper is to study the influence of these particles on stability by comparison with stability results from the single phase studies, in a plane two-dimensional configuration. The particles are supposed to be chemically inert and of a uniform size. In order to carry out a linear stability study for this flow modified by the presence of particles, the mean particle velocity field is first determined, assuming that only the gas exerts forces on the particles. This field is sought in a self similar form, which imposes a limit on the size of the particles. However, the particle mass concentration cannot be obtained in a self similar form, but can only, be described by a partial differential equation. The mean flow characteristics being determined, the spectrum of the discretized linear stability operator shows first that particle addition does not trigger any new 'dangerous' modes compared with the single phase flow case. It also shows that the most amplified mode in the case of the single phase flow remains the most amplified mode in the case of the two phase flow. Moreover, the addition of particles acts continuously upon stability results, behaving linearly with respect to the particle mass concentration when the latter is small. The linear correction to the monophasic mode, as well as the evolution of the modes with weak values of the particle mass concentration at the wall, are shown to be proportional to the ejection velocity of

  16. Cross-flow analysis of injection wells in a multilayered reservoir

    Directory of Open Access Journals (Sweden)

    Mohammadreza Jalali

    2016-09-01

    Natural and forced cross-flow is modeled for some injection wells in an oil reservoir located at North Sea. The solution uses a transient implicit finite difference approach for multiple sand layers with different permeabilities separated by impermeable shale layers. Natural and forced cross-flow rates for each reservoir layer during shut-in are calculated and compared with different production logging tool (PLT measurements. It appears that forced cross-flow is usually more prolonged and subject to a higher flow rate when compared with natural cross-flow, and is thus worthy of more detailed analysis.

  17. Ionophore-Based Potentiometric Sensors for the Flow-Injection Determination of Promethazine Hydrochloride in Pharmaceutical Formulations and Human Urine

    Directory of Open Access Journals (Sweden)

    Suad Mustafa Al-Araji

    2011-01-01

    Full Text Available Plasticised poly(vinyl chloride-based membranes containing the ionophores (α-, β- and γ-cyclodextrins (CD, dibenzo-18-crown-6 (DB18C6 and dibenzo-30-crown-10 (DB30C10 were evaluated for their potentiometric response towards promethazine (PM in a flow injection analysis (FIA set-up. Good responses were obtained when β- and γ-CDs, and DB30C10 were used. The performance characteristics were further improved when tetrakis(4-chlorophenyl borate (KTPB was added to the membrane. The sensor based on β-CD, bis(2-ethylhexyl adipate (BEHA and KTPB exhibited the best performance among the eighteen sensor compositions that were tested. The response was linear from 1 x 10−5 to 1 x 10−2 M, slope was 61.3 mV decade−1, the pH independent region ranged from 4.5 to 7.0, a limit of detection of 5.3 x 10−6 M was possible and a lifetime of more than a month was observed when used in the FIA system. Other plasticisers such as dioctyl phenylphosphonate and tributyl phosphate do not show significant improvements in the quality of the sensors. The promising sensors were further tested for the effects of foreign ions (Li+, Na+, K+, Mg2+, Ca2+, Co2+, Cu2+, Cr3+, Fe3+, glucose, fructose. FIA conditions (e.g., effects of flow rate, injection volume, pH of the carrier stream were also studied when the best sensor was used (based on β-CD. The sensor was applied to the determination of PM in four pharmaceutical preparations and human urine that were spiked with different levels of PM. Good agreement between the sensor and the manufacturer’s claimed values (for pharmaceutical preparations was obtained, while mean recoveries of 98.6% were obtained for spiked urine samples. The molecular recognition features of the sensors as revealed by molecular modelling were rationalised by the nature of the interactions and complexation energies between the host and guest molecules.

  18. Flow injection analysis-flame atomic absorption spectrometry system for indirect determination of cyanide using cadmium carbonate as a new solid-phase reactor

    International Nuclear Information System (INIS)

    Noroozifar, M.; Khorasani-Motlagh, M.; Hosseini, S.-N.

    2005-01-01

    A new and simple flow injection system procedure has been developed for the indirect determination of cyanide. The method is based on insertion of aqueous cyanide solutions into an on-line cadmium carbonate packed column (25% m/m suspended on silica gel beads) and a sodium hydroxide with pH 10 is used as the carrier stream. The eluent containing the analyte as cadmiumcyanide complexes, produced from reaction between cadmium carbonate and cyanide, measured by flame atomic absorption spectrometry. The absorbance is proportional to the concentration of cyanide in the sample. The linear range of the system is up to 15 mg L -1 with a detection limit 0.2 mg L -1 and sampling rate 72 h -1 . The method is suitable for determination of cyanide in industrial waste waters with a relative standard deviation better than 1.22%

  19. Flow regime analysis for fluid injection into a confined aquifer: implications for CO2 sequestration

    Science.gov (United States)

    Guo, B.; Zheng, Z.; Celia, M. A.; Stone, H.

    2015-12-01

    Carbon dioxide injection into a confined saline aquifer may be modeled as an axisymmetric two-phase flow problem. Assuming the two fluids segregate in the vertical direction due to strong buoyancy, and neglecting capillary pressure and miscibility, the lubrication approximation leads to a nonlinear advection-diffusion equation that describes the evolution of the sharp fluid-fluid interface. The flow behaviors in the system are controlled by two dimensionless groups: M, the viscosity ratio of the displaced fluid relative to injected fluid, and Γ , the gravity number, which represents the relative importance of buoyancy and fluid injection. Four different analytical solutions can be derived as the asymptotic approximations, representing specific values of the parameter pairs. The four solutions correspond to: (1) Γ 1; and (4) Γ >> 1, any M values. The first two of these solutions are new, while the third corresponds to the solution of Nordbotten and Celia (2006) for confined injections and the fourth corresponds to the solution of (Lyle et al., 2005) for gravity currents in an unconfined aquifer. Overall, the various axisymmetric flows can be summarized in a Γ-M regime diagram with five distinct dynamic behaviors including the four asymptotic regimes and an intermediate regime (Fig. 1). Data from a number of CO2 injection sites around the world can be used to compute the two dimensionless groups Γ and M associated with each injection. When plotted on the regime diagram, these values show the flow behavior for each injection and how the values vary from site to site. For all the CO2 injections, M is always larger than 1, while Γ can range from 0.01 up to 100. The pairs of (Γ, M) with lower Γ values correspond to solution (3), while the ones with higher Γ values can move up to the intermediate regime and the flow regime for solution (4). The higher values of Γ correspond to pilot-scale injections with low injection rates; most industrial-scale injection

  20. Water injection profiling by nuclear logging

    International Nuclear Information System (INIS)

    Arnold, D.M.

    1980-01-01

    This invention relates to nuclear logging techniques for determining the volume flow rates and flow directions of injected water moving behind a wellbore casing. The apparatus includes a sonde equipped with a neutron source and dual radiation detectors. Oxygen in the neutron irradiated water is transmitted to 16 N and the resultant primary and Compton scattered gamma rays are detected in two energy windows by both detectors. Count rate data is analysed in terms of the windows to obtain linear flow velocities for water flow within and behind the casing. Volume flow rates are determined for upward and downward flow, and horizontal volume flow into the surrounding formation is calculated. A complete injection profile may thus be obtained. (U.K.)

  1. Determination of available phosphorus in soils by using a new extraction procedure and a flow injection amperometric system.

    Science.gov (United States)

    Jakmunee, Jaroon; Junsomboon, Jaroon

    2009-09-15

    A new extraction procedure based on an off-line extraction column was proposed for extracting of available phosphorus from soils. The column was fabricated from a plastic syringe fitted at the bottom with a cotton wool and a piece of filter paper to support a soil sample. An aliquot (50 mL) of extracting solution (0.05 M HCl+0.0125 M H(2)SO(4)) was used to extract the sample under gravity flow and the eluate was collected in a polyethylene bottle. The extract was then analyzed for phosphorus contents by a simple flow injection amperometric system, employing a set of three-way solenoid valves as an injection valve. The method is based on the electrochemical reduction of 12-molybdophosphate which is produced on-line by the reaction of orthophosphate with acidic molybdate and the electrical current produced was directly proportional to the concentration of phosphate in range of 0.1-10.0 mg L(-1) PO(4)-P, with a detection limit of 0.02 mg L(-1). Relative standard for 11 replicate injections of 5 mg L(-1) PO(4)-P was 0.5%. A sample through put of 35 h(-1) was achieved, with consumption of 14 mg KCl, 10mg ammonium molybdate and 0.05 mL H(2)SO(4) per analysis. The detection system does not suffer from the interferences that are encountered in the photometric method such as colored substances, colloids, metal ions, silicate and refractive index effect (Schlieren effect). The results obtained by the column extraction procedure were well correlated with those obtained by the steady-state extraction procedure, but showed slightly higher extraction efficiency.

  2. Determination of Noncovalent Binding Using a Continuous Stirred Tank Reactor as a Flow Injection Device Coupled to Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Santos, Inês C.; Waybright, Veronica B.; Fan, Hui; Ramirez, Sabra; Mesquita, Raquel B. R.; Rangel, António O. S. S.; Fryčák, Petr; Schug, Kevin A.

    2015-07-01

    Described is a new method based on the concept of controlled band dispersion, achieved by hyphenating flow injection analysis with ESI-MS for noncovalent binding determinations. A continuous stirred tank reactor (CSTR) was used as a FIA device for exponential dilution of an equimolar host-guest solution over time. The data obtained was treated for the noncovalent binding determination using an equimolar binding model. Dissociation constants between vancomycin and Ac-Lys(Ac)-Ala-Ala-OH peptide stereoisomers were determined using both the positive and negative ionization modes. The results obtained for Ac- L-Lys(Ac)- D-Ala- D-Ala (a model for a Gram-positive bacterial cell wall) binding were in reasonable agreement with literature values made by other mass spectrometry binding determination techniques. Also, the developed method allowed the determination of dissociation constants for vancomycin with Ac- L-Lys(Ac)- D-Ala- L-Ala, Ac- L-Lys(Ac)- L-Ala- D-Ala, and Ac- L-Lys(Ac)- L-Ala- L-Ala. Although some differences in measured binding affinities were noted using different ionization modes, the results of each determination were generally consistent. Differences are likely attributable to the influence of a pseudo-physiological ammonium acetate buffer solution on the formation of positively- and negatively-charged ionic complexes.

  3. Determination of splenic blood flow by inhalation of radioactive rare gases

    Energy Technology Data Exchange (ETDEWEB)

    Huchzermeyer, H; Schmitz-Feuerhake, I; Reblin, T [Medizinische Hochschule Hannover (Germany, F.R.). Abt. fuer Nuklearmedizin und Spezielle Biophysik; Medizinische Hochschule Hannover (Germany, F.R.). Abt. fuer Gastroenterologie)

    1977-10-01

    We have evaluated the /sup 133/Xenon inhalation method for the determination of splenic blood flow. In twenty-two healthy persons the blood flow was on average 109 +- 4 ml/100 g x min, which is equivalent to a total blood flow of about 170 ml/min. In patients with chronic fatty liver hepatitis specific blood flow was reduced (81 +- 10 ml/100 g x min) as it was in patients with cirrhotic liver without splenomegaly (75 +- 2 ml/100 g x min.). With increasing weight of the spleen, the total blood flow rises, although specific blood flow is low. Our results obtained by the /sup 133/Xenon inhalation method are similar to results obtained by others using intraarterial injection of tracer gas. The advantages of the inhalation method as a non-traumatic method are: 1) the stress for the patient is very small; 2) blood flow measurements can be repeated within short periods of time. We consider for the present the /sup 133/Xenon inhalation method to be the method of choice for the determination of the splenic blood flow.

  4. In-line electrochemical reagent generation coupled to a flow injection biamperometric system for the determination of sulfite in beverage samples.

    Science.gov (United States)

    de Paula, Nattany T G; Barbosa, Elaine M O; da Silva, Paulo A B; de Souza, Gustavo C S; Nascimento, Valberes B; Lavorante, André F

    2016-07-15

    This work reports an in-line electrochemical reagent generation coupled to a flow injection biamperometric procedure for the determination of SO3(2-). The method was based on a redox reaction between the I3(-) and SO3(2-) ions, after the diffusion of SO2 through a gas diffusion chamber. Under optimum experimental conditions, a linear response ranging from 1.0 to 12.0 mg L(-1) (R=0.9999 and n=7), a detection and quantification limit estimated at 0.26 and 0.86 mg L(-1), respectively, a standard deviation relative of 0.4% (n=10) for a reference solution of 4.0 mg L(-1) SO3(2-) and sampling throughput for 40 determinations per hour were achieved. Addition and recovery tests with juice and wine samples were performed resulting in a range between 92% and 110%. There were no significant differences at a 95% confidence level in the analysis of eight samples when comparing the new method with a reference procedure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Flow rate dependent extra-column variance from injection in capillary liquid chromatography.

    Science.gov (United States)

    Aggarwal, Pankaj; Liu, Kun; Sharma, Sonika; Lawson, John S; Dennis Tolley, H; Lee, Milton L

    2015-02-06

    Efficiency and resolution in capillary liquid chromatography (LC) can be significantly affected by extra-column band broadening, especially for isocratic separations. This is particularly a concern in evaluating column bed structure using non-retained test compounds. The band broadening due to an injector supplied with a commercially available capillary LC system was characterized from experimental measurements. The extra-column variance from the injection valve was found to have an extra-column contribution independent of the injection volume, showing an exponential dependence on flow rate. The overall extra-column variance from the injection valve was found to vary from 34 to 23 nL. A new mathematical model was derived that explains this exponential contribution of extra-column variance on chromatographic performance. The chromatographic efficiency was compromised by ∼130% for a non-retained analyte because of injection valve dead volume. The measured chromatographic efficiency was greatly improved when a new nano-flow pumping system with integrated injection valve was used. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Re-injection feasibility study of fracturing flow-back fluid in shale gas mining

    Science.gov (United States)

    Kang, Dingyu; Xue, Chen; Chen, Xinjian; Du, Jiajia; Shi, Shengwei; Qu, Chengtun; Yu, Tao

    2018-02-01

    Fracturing flow-back fluid in shale gas mining is usually treated by re-injecting into formation. After treatment, the fracturing flow-back fluid is injected back into the formation. In order to ensure that it will not cause too much damage to the bottom layer, feasibility evaluations of re-injection of two kinds of fracturing fluid with different salinity were researched. The experimental research of the compatibility of mixed water samples based on the static simulation method was conducted. Through the analysis of ion concentration, the amount of scale buildup and clay swelling rate, the feasibility of re-injection of different fracturing fluid were studied. The result shows that the swelling of the clay expansion rate of treated fracturing fluid is lower than the mixed water of treated fracturing fluid and the distilled water, indicating that in terms of clay expansion rate, the treated fracturing flow-back fluid is better than that of water injection after re-injection. In the compatibility test, the maximum amount of fouling in the Yangzhou oilfield is 12mg/L, and the maximum value of calcium loss rate is 1.47%, indicating that the compatibility is good. For the fracturing fluid with high salinity in the Yanchang oilfield, the maximum amount of scaling is 72mg/L, and the maximum calcium loss rate is 3.50%, indicating that the compatibility is better.

  7. Rapid dual-injection single-scan 13N-ammonia PET for quantification of rest and stress myocardial blood flows

    International Nuclear Information System (INIS)

    Rust, T C; DiBella, E V R; McGann, C J; Christian, P E; Hoffman, J M; Kadrmas, D J

    2006-01-01

    Quantification of myocardial blood flows at rest and stress using 13 N-ammonia PET is an established method; however, current techniques require a waiting period of about 1 h between scans. The objective of this study was to test a rapid dual-injection single-scan approach, where 13 N-ammonia injections are administered 10 min apart during rest and adenosine stress. Dynamic PET data were acquired in six human subjects using imaging protocols that provided separate single-injection scans as gold standards. Rest and stress data were combined to emulate rapid dual-injection data so that the underlying activity from each injection was known exactly. Regional blood flow estimates were computed from the dual-injection data using two methods: background subtraction and combined modelling. The rapid dual-injection approach provided blood flow estimates very similar to the conventional single-injection standards. Rest blood flow estimates were affected very little by the dual-injection approach, and stress estimates correlated strongly with separate single-injection values (r = 0.998, mean absolute difference = 0.06 ml min -1 g -1 ). An actual rapid dual-injection scan was successfully acquired in one subject and further demonstrates feasibility of the method. This study with a limited dataset demonstrates that blood flow quantification can be obtained in only 20 min by the rapid dual-injection approach with accuracy similar to that of conventional separate rest and stress scans. The rapid dual-injection approach merits further development and additional evaluation for potential clinical use

  8. A comparison of continuous pneumatic nebulization and flow injection-direct injection nebulization for sample introduction in inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Crain, J.S.; Kiely, J.T.

    1995-08-01

    Dilute nitric acid blanks and solutions containing Ni, Cd, Pb, and U (including two laboratory waste samples) were analyzed eighteen times over a two-month period using inductively coupled plasma-mass spectrometry (ICP-MS). Two different sample introduction techniques were employed: flow injection-direct injection nebulization (FI-DIN) and continuous pneumatic nebulization (CPN). Using comparable instrumental measurement procedures, FI-DIN analyses were 33% faster and generated 52% less waste than CPN analyses. Instrumental limits of detection obtained with FI-DIN and CPN were comparable but not equivalent (except in the case of Pb) because of nebulizer-related differences in sensitivity (i.e., signal per unit analyte concentration) and background. Substantial and statistically significant differences were found between FI-DIN and CPN Ni determinations, and in the case of the laboratory waste samples, there were also small but statistically significant differences between Cd determinations. These small (2 to 3%) differences were not related to polyatomic ion interference (e.g., 95 Mo 16 O + ), but in light of the time savings and waste reduction to be realized, they should not preclude the use of FI-DIN in place of CPN for determination of Cd, Pb, U and chemically

  9. Flow Injection Analysis: A Revolution in Modern Analytical Chemistry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    1996-01-01

    A review is made of the fundamentals of Flow Injection Analysis (FIA), and the versatility and applicability of this analytical concept is demonstrated by a series of examples, comprizing the use of different types of FIA-manifolds and various detection devices (optical and electrochemical...

  10. An automatic flow injection analysis procedure for photometric determination of ethanol in red wine without using a chromogenic reagent.

    Science.gov (United States)

    Borges, Sivanildo S; Frizzarin, Rejane M; Reis, Boaventura F

    2006-05-01

    An automatic reagentless photometric procedure for the determination of ethanol in red wine is described. The procedure was based on a falling drop system that was implemented by employing a flow injection analysis manifold. The detection system comprised an infrared LED and a phototransistor. The experimental arrangement was designed to ensure that the wine drop grew between these devices, thus causing a decrease in the intensity of the radiation beam coming from the LED. Since ethanol content affected the size of the wine drop this feature was exploited to develop an analytical procedure for the photometric determination of ethanol in red wine without using a chromogenic reagent. In an attempt to prove the usefulness of the proposed procedure, a set of red wines were analysed. No significant difference between our results and those obtained with a reference method was observed at the 95% confidence level. Other advantages of our method were a linear response ranging from 0.17 up to 5.14 mol L(-1) (1.0 up to 30.0%) ethanol (R = 0.999); a limit of detection of 0.05 mol L(-1) (0.3%) ethanol; a relative standard deviation of 2.5% (n = 10) using typical wine sample containing 2.14 mol L(-1) (12.5%) ethanol; and a sampling rate of 50 determinations per hour.

  11. Liquid sprays and flow studies in the direct-injection diesel engine under motored conditions

    Science.gov (United States)

    Nguyen, Hung Lee; Carpenter, Mark H.; Ramos, Juan I.; Schock, Harold J.; Stegeman, James D.

    1988-01-01

    A two dimensional, implicit finite difference method of the control volume variety, a two equation model of turbulence, and a discrete droplet model were used to study the flow field, turbulence levels, fuel penetration, vaporization, and mixing in diesel engine environments. The model was also used to study the effects of engine speed, injection angle, spray cone angle, droplet distribution, and intake swirl angle on the flow field, spray penetration and vaporization, and turbulence in motored two-stroke diesel engines. It is shown that there are optimum conditions for injection, which depend on droplet distribution, swirl, spray cone angle, and injection angle. The optimum conditions result in good spray penetration and vaporization and in good fuel mixing. The calculation presented clearly indicates that internal combustion engine models can be used to assess, at least qualitatively, the effects of injection characteristics and engine operating conditions on the flow field and on the spray penetration and vaporization in diesel engines.

  12. Rapid food decomposition by H2O2-H2SO4 for determination of total mercury by flow injection cold vapor atomic absorption spectrometry.

    Science.gov (United States)

    Zenebon, Odair; Sakuma, Alice M; Dovidauskas, Sergio; Okada, Isaura A; de, MaioFrancaD; Lichtig, Jaim

    2002-01-01

    A mixture of 50% H2O2-H2SO4 (3 + 1, v/v) was used for decomposition of food in open vessels at 80 degrees C. The treatment allowed rapid total mercury determination by flow injection cold vapor atomic absorption spectrometry. Cabbage, potatoes, peanuts paste, hazelnuts paste, oats, tomatoes and their derivatives, oysters, shrimps, prawns, shellfish, marine algae, and many kinds of fish were analyzed by the proposed methodology with a limit of quantitation of 0.86 +/- 0.08 microg/L mercury in the final solution. Reference materials tested also gave excellent recovery.

  13. Numerical investigation of the air injection effect on the cavitating flow in Francis hydro turbine

    Science.gov (United States)

    Chirkov, D. V.; Shcherbakov, P. K.; Cherny, S. G.; Skorospelov, V. A.; Turuk, P. A.

    2017-09-01

    At full and over load operating points, some Francis turbines experience strong self-excited pressure and power oscillations. These oscillations are occuring due to the hydrodynamic instability of the cavitating fluid flow. In many cases, the amplitude of such pulsations may be reduced substantially during the turbine operation by the air injection/ admission below the runner. Such an effect is investigated numerically in the present work. To this end, the hybrid one-three-dimensional model of the flow of the mixture "liquid-vapor" in the duct of a hydroelectric power station, which was proposed previously by the present authors, is augmented by the second gaseous component — the noncondensable air. The boundary conditions and the numerical method for solving the equations of the model are described. To check the accuracy of computing the interface "liquid-gas", the numerical method was applied at first for solving the dam break problem. The algorithm was then used for modeling the flow in a hydraulic turbine with air injection below the runner. It is shown that with increasing flow rate of the injected air, the amplitude of pressure pulsations decreases. The mechanism of the flow structure alteration in the draft tube cone has been elucidated, which leads to flow stabilization at air injection.

  14. Study of process parameters effect on the filling phase of micro injection moulding using weld lines as flow markers

    DEFF Research Database (Denmark)

    Tosello, Guido; Gava, Alberto; Hansen, Hans Nørgaard

    2010-01-01

    , the relationships between the filling pattern and the different process parameter settings have to be established. In this paper, a novel approach based on the use of weld lines as flow markers to trace the development of the flow front during the filling is proposed. The effects on the filling stage of process......Micro-injection moulding (micro-moulding) is a process which enables the mass production of polymer microproducts. In order to produce high-quality injection moulded micro-parts, a crucial aspect to be fully understood and optimised is the filling of the cavity by the molten polymer. As a result...... manufactured by micro-electrodischarge machining. A commercially available polystyrene grade polymer has been moulded using a high-speed injection moulding machine. The design of experiment technique was employed to determine the effect of the process parameters on the filling phase of the micro...

  15. Calculation method of water injection forward modeling and inversion process in oilfield water injection network

    Science.gov (United States)

    Liu, Long; Liu, Wei

    2018-04-01

    A forward modeling and inversion algorithm is adopted in order to determine the water injection plan in the oilfield water injection network. The main idea of the algorithm is shown as follows: firstly, the oilfield water injection network is inversely calculated. The pumping station demand flow is calculated. Then, forward modeling calculation is carried out for judging whether all water injection wells meet the requirements of injection allocation or not. If all water injection wells meet the requirements of injection allocation, calculation is stopped, otherwise the demand injection allocation flow rate of certain step size is reduced aiming at water injection wells which do not meet requirements, and next iterative operation is started. It is not necessary to list the algorithm into water injection network system algorithm, which can be realized easily. Iterative method is used, which is suitable for computer programming. Experimental result shows that the algorithm is fast and accurate.

  16. Dispersive liquid-liquid microextraction followed by flow injection-inductively coupled plasma mass spectrometry (FI-ICPMS) determination of 14 lanthanides from ground water

    International Nuclear Information System (INIS)

    Chandrasekaran, K.; Karunasagar, D.; Arunachalam, J.

    2011-01-01

    The aim of the present work was to develop a dispersive liquid-liquid microextraction (DLLME) method for the sensitive determination of REEs at a few parts per billion in groundwater by flow injection-inductively coupled plasma mass spectrometry (FI-ICPMS). In the developed method, methanol (500 μl) and chloroform (200μl) were used as the disperser and extractant respectively. The REEs were complexed with 4-(2-pyridylazo resorcinol) (PAR) at a pH of 7. Acetate ion was added as an auxiliary ligand for neutralization of the charge on the lanthanide-PAR complex. The disperser (MeOH) - extraction solvent (CHCl 3 ) mixture was rapidly injected using a disposable syringe, thereby forming a cloudy solution. The lanthanide-PAR complex was extracted into the fine droplets of the chloroform dispersed in the aqueous phase. The solution was centrifuged and the aqueous layer at the top was discarded. The REEs were back extracted from the chloroform layer with nitric acid for determination by ICPMS. Important parameters for complex formation and extraction, such as volume of extraction/disperser solvent, extraction time, pH and concentration of the chelating agent and the auxiliary ligand are being optimized using ICP-MS. The optimization is being carried out at 5 μg L -1 concentration level of REE in the initial water sample. Preliminary studies have shown an extraction recovery of 80-85% for all the 14 lanthanide elements and these will be presented

  17. Numerical Simulation of Polymer Injection in Turbulent Flow Past a Circular Cylinder

    KAUST Repository

    Richter, David; Shaqfeh, Eric S. G.; Iaccarino, Gianluca

    2011-01-01

    Using a code developed to compute high Reynolds number viscoelastic flows, polymer injection from the upstream stagnation point of a circular cylinder is modeled at Re = 3900. Polymer stresses are represented using the FENE-P constitutive equations. By increasing polymer injection rates within realistic ranges, significant near wake stabilization is observed. Rather than a turbulent detached shear layer giving way to a chaotic primary vortex (as seen in Newtonian flows at high Re), a much more coherent primary vortex is shed, which possesses an increased core pressure as well as a reduced level of turbulent energy. © 2011 American Society of Mechanical Engineers.

  18. Detailed evaluation of the natural circulation mass flow rate of water propelled by using an air injection

    International Nuclear Information System (INIS)

    Park, Rae-Joon; Ha, Kwang-Soon; Kim, Jae-Cheol; Hong, Seong-Wan; Kim, Sang-Baik

    2008-01-01

    One-dimensional (1D) air-water two-phase natural circulation flow in the thermohydraulic evaluation of reactor cooling mechanism by external self-induced flow - one-dimensional' (THERMES-1D) experiment has been verified and evaluated by using the RELAP5/MOD3 computer code. Experimental results on the 1D natural circulation mass flow rate of water propelled by using an air injection have been evaluated in detail. The RELAP5 results have shown that an increase in the air injection rate to 50% of the total heat flux leads to an increase in the water circulation mass flow rate. However, an increase in the air injection rate from 50 to 100% does not affect the water circulation mass flow rate, because of the inlet area condition. As the height increases in the air injection part, the void fraction increases. However, the void fraction in the upper part of the air injector maintains a constant value. An increase in the air injection mass flow rate leads to an increase in the local void fraction, but it has no influence on the local pressure. An increase in the coolant inlet area leads to an increase in the water circulation mass flow rate. However, the water outlet area does not have an influence on the water circulation mass flow rate. As the coolant outlet moves to a lower position, the water circulation mass flow rate decreases. (author)

  19. Decompositions of injection patterns for nodal flow allocation in renewable electricity networks

    Science.gov (United States)

    Schäfer, Mirko; Tranberg, Bo; Hempel, Sabrina; Schramm, Stefan; Greiner, Martin

    2017-08-01

    The large-scale integration of fluctuating renewable power generation represents a challenge to the technical and economical design of a sustainable future electricity system. In this context, the increasing significance of long-range power transmission calls for innovative methods to understand the emerging complex flow patterns and to integrate price signals about the respective infrastructure needs into the energy market design. We introduce a decomposition method of injection patterns. Contrary to standard flow tracing approaches, it provides nodal allocations of link flows and costs in electricity networks by decomposing the network injection pattern into market-inspired elementary import/export building blocks. We apply the new approach to a simplified data-driven model of a European electricity grid with a high share of renewable wind and solar power generation.

  20. Flow-injection system for automated dissolution testing of isoniazid tablets with chemiluminescence detection.

    Science.gov (United States)

    Li, B; Zhang, Z; Liu, W

    2001-05-30

    A simple and sensitive flow-injection chemiluminescence (CL) system for automated dissolution testing is described and evaluated for monitoring of dissolution profiles of isoniazid tablets. The undissolved suspended particles in the dissolved solution were eliminated via on-line filter. The novel CL system of KIO(4)-isoniazid was also investigated. The sampling frequency of the system was 120 h(-1). The dissolution profiles of isoniazid fast-release tablets from three sources were determined, which demonstrates the stability, great sensitivity, large dynamic measuring range and robustness of the system.

  1. Study of process parameters on two phase flow agitated by top blowing lance injection into a bath

    Energy Technology Data Exchange (ETDEWEB)

    Xia Jiliang; Ahokainen, T.; Holappa, L.

    1998-12-31

    Numerical investigation has been carried out for two phase flow in a bath agitated by top blowing lance injection. Eulerian two phase flow model is used. Lance immersion depth, injection gas flow rate, nozzle diameter, and bubble size have been systematically changed to examine their influence on the flow characteristics in the bath. It is found that there appear three typical flow patterns: one-vortex, two-vortex, and three-vortex type, with changing the injection gas flow rate or/and the nozzle diameter at moderate lance immersion depth. Predicted velocities are in a good agreement with Iguchi et al.`s experimental data and the main findings are also consistent with the measurements and observations of Chatterjee and Hsiao and Lehner. (orig.) 24 refs. Computational Fluid Dynamics Technology Programme

  2. Bienzymatic Biosensor for Rapid Detection of Aspartame by Flow Injection Analysis

    Directory of Open Access Journals (Sweden)

    Maria-Cristina Radulescu

    2014-01-01

    Full Text Available A rapid, simple and stable biosensor for aspartame detection was developed. Alcohol oxidase (AOX, carboxyl esterase (CaE and bovine serum albumin (BSA were immobilised with glutaraldehyde (GA onto screen-printed electrodes modified with cobalt-phthalocyanine (CoPC. The biosensor response was fast. The sample throughput using a flow injection analysis (FIA system was 40 h−1 with an RSD of 2.7%. The detection limits for both batch and FIA measurements were 0.1 µM for methanol and 0.2 µM for aspartame, respectively. The enzymatic biosensor was successfully applied for aspartame determination in different sample matrices/commercial products (liquid and solid samples without any pre-treatment step prior to measurement.

  3. Bienzymatic biosensor for rapid detection of aspartame by flow injection analysis.

    Science.gov (United States)

    Radulescu, Maria-Cristina; Bucur, Bogdan; Bucur, Madalina-Petruta; Radu, Gabriel Lucian

    2014-01-09

    A rapid, simple and stable biosensor for aspartame detection was developed. Alcohol oxidase (AOX), carboxyl esterase (CaE) and bovine serum albumin (BSA) were immobilised with glutaraldehyde (GA) onto screen-printed electrodes modified with cobalt-phthalocyanine (CoPC). The biosensor response was fast. The sample throughput using a flow injection analysis (FIA) system was 40 h⁻¹ with an RSD of 2.7%. The detection limits for both batch and FIA measurements were 0.1 µM for methanol and 0.2 µM for aspartame, respectively. The enzymatic biosensor was successfully applied for aspartame determination in different sample matrices/commercial products (liquid and solid samples) without any pre-treatment step prior to measurement.

  4. On-line complexation/cloud point preconcentration for the sensitive determination of dysprosium in urine by flow injection inductively coupled plasma-optical emission spectrometry

    International Nuclear Information System (INIS)

    Ortega, Claudia; Cerutti, Soledad; Silva, Maria F.; Olsina, Roberto A.; Martinez, Luis D.

    2003-01-01

    An on-line dysprosium preconcentration and determination system based on the hyphenation of cloud point extraction (CPE) to flow injection analysis (FIA) associated with ICP-OES was studied. For the preconcentration of dysprosium, a Dy(III)-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex was formed on-line at pH 9.22 in the presence of nonionic micelles of PONPE-7.5. The micellar system containing the complex was thermostated at 30 C in order to promote phase separation, and the surfactant-rich phase was retained in a microcolumn packed with cotton at pH 9.2. The surfactant-rich phase was eluted with 4 mol L -1 nitric acid at a flow rate of 1.5 mL min -1 , directly in the nebulizer of the plasma. An enhancement factor of 50 was obtained for the preconcentration of 50 mL of sample solution. The detection limit value for the preconcentration of 50 mL of aqueous solution of Dy was 0.03 μg L -1 . The precision for 10 replicate determinations at the 2.0 μg L -1 Dy level was 2.2% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for dysprosium was linear with a correlation coefficient of 0.9994 at levels near the detection limits up to at least 100 μg L -1 . The method was successfully applied to the determination of dysprosium in urine. (orig.)

  5. Flow injection determination of choline in milk hydrolysates by an immobilized enzyme reactor coupled to a selective hydrogen peroxide amperometric sensor

    Energy Technology Data Exchange (ETDEWEB)

    Pati, Sandra [Dipartimento di Chimica, Universita degli Studi di Bari, Via Orabona 4, 70126 Bari (Italy); Quinto, Maurizio [Dipartimento di Scienze Agroambientali, Chimica e Difesa Vegetale, Universita degli Studi di Foggia, Via Napoli 25, 71100 Foggia (Italy); Palmisano, Francesco [Dipartimento di Chimica, Universita degli Studi di Bari, Via Orabona 4, 70126 Bari (Italy)]. E-mail: palmisano@chimica.uniba.it

    2007-07-02

    A choline oxidase (ChO) immobilized enzyme reactor (IMER) prepared by glutaraldehyde coupling of the enzyme on aminopropyl modified controlled pore glass beads is described. The ChO-IMER was coupled, in a flow injection configuration system, to an interference free hydrogen peroxide amperometric sensor based on a Pt surface modified by an overoxidized polypyrrole film. The resulting analytical device responds selectively to choline and displays a sensitivity of 46.9 {+-} 0.2 {mu}C mM{sup -1} and a limit of detection, calculated at a signal-to-noise ratio equal to 3, of 7 {mu}M. Sensitivity remains constant for about 20 days and then starts to slowly deteriorate and after 2 months a 70% of the initial sensitivity was still retained. The application to choline determination in milk hydrolysates is demonstrated. Short- and long-term drift observed in the analytical response can be corrected by a bracketing technique.

  6. Mathematical modeling of flow-injection techniques and their applications for environmental monitoring

    International Nuclear Information System (INIS)

    Begum, N.N.; Ahmed, J.

    2006-01-01

    A classification of the existing mathematical models of flow-injection (FI) manifolds based on the main principles on which they are built, have been proposed. Numerous mathematical models of FI systems employing ideas from different scientific areas (e.g. mathematical statistics, chemical engineering, chromatography) have been developed so far. The models have been compared with respect to their predictive power, the complexity of their mathematical treatment, and the requirements for computation time when applied to single-line, multi-channel and conjugated two-line FI systems. It is concluded that the axially dispersed plug flow model deserves special attention because it offers an acceptable compromise between the conflicting requirements for maximal possible mathematical simplicity and maximal possible precision. Applicability of these existing flow-injection models to single-line, multi-channel and conjugated two-line systems for environmental monitoring have been discussed. (author)

  7. Transverse injection into Mach 2 flow behind a rearward-facing step - A 3-D, compressible flow test case for hypersonic combustor CFD validation

    Science.gov (United States)

    Mcdaniel, James C.; Fletcher, Douglas G.; Hartfield, Roy J.; Hollo, Steven D.

    1991-01-01

    A spatially-complete data set of the important primitive flow variables is presented for the complex, nonreacting, 3D unit combustor flow field employing transverse injection into a Mach 2 flow behind a rearward-facing step. A unique wind tunnel facility providing the capability for iodine seeding was built specifically for these measurements. Two optical techniques based on laser-induced-iodine fluorescence were developed and utilized for nonintrusive, in situ flow field measurements. LDA provided both mean and fluctuating velocity component measurements. A thermographic phosphor wall temperature measurement technique was developed and employed. Data from the 2D flow over a rearward-facing step and the complex 3D mixing flow with injection are reported.

  8. A simple and sensitive flow injection method based on the catalytic activity of CdS quantum dots in an acidic permanganate chemiluminescence system for determination of formaldehyde in water and wastewater.

    Science.gov (United States)

    Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza

    2016-04-01

    A simple and sensitive flow injection chemiluminescence (CL) method in which CdS quantum dots (QDs) enhanced the CL intensity of a KMnO4-formaldehyde (HCHO) reaction was offered for the determination of HCHO. This CL system was based on the catalytic activity of CdS QDs and their participation in the CL resonance energy transfer (CRET) phenomenon. A possible mechanism for the supplied CL system was proposed using the kinetic curves of the CL systems and the spectra of CL, photoluminescence (PL) and ultraviolet-visible (UV-Vis). The emanated CL intensity of the KMnO4-CdS QDs system was amplified in the presence of a trace level of HCHO. Based on this enhancement effect, a simple and sensitive flow injection CL method was suggested for the determination of HCHO concentration in environmental water and wastewater samples. Under selected optimized experimental conditions, the increased CL intensity was proportional to the HCHO concentration in the range of 0.03-4.5 μg L(-1) and 4.5-10.0 μg L(-1). The detection limits (3σ) were 0.0003 μg L(-1) and 1.2 μg L(-1). The relative standard deviations (RSD%) for eleven replicate determinations of 4.0 μg L(-1) HCHO were 2.2%. Furthermore, the feasibility of the developed method was investigated via the determination of HCHO concentration in environmental water and wastewater samples.

  9. Determination of scandium in acid mine drainage by ICP-OES with flow injection on-line preconcentration using oxidized multiwalled carbon nanotubes.

    Science.gov (United States)

    Jerez, Javier; Isaguirre, Andrea C; Bazán, Cristian; Martinez, Luis D; Cerutti, Soledad

    2014-06-01

    An on-line scandium preconcentration and determination system implemented with inductively coupled plasma optical emission spectrometry associated with flow injection was studied. Trace amounts of scandium were preconcentrated by sorption on a minicolumn packed with oxidized multiwalled carbon nanotubes, at pH 1.5. The retained analyte was removed from the minicolumn with 30% (v/v) nitric acid. A total enrichment factor of 225-fold was obtained within a preconcentration time of 300 s (for a 25 mL sample volume). The overall time required for preconcentration and elution of 25 mL of sample was about 6 min; the throughput was about 10 samples per hour. The value of the detection limit was 4 ng L(-1) and the precision for 10 replicate determinations at 100 ng L(-1) Sc level was 5% relative standard deviation, calculated from the peak heights obtained. The calibration graph using the preconcentration system was linear with a correlation coefficient of 0.9996 at levels near the detection limits up to at least 10 mg L(-1). After optimization, the method was successfully applied to the determination of Sc in an acid drainage from an abandoned mine located in the province of San Luis, Argentina. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Comparison of Descemet stripping under continuous air flow, manual air injection and balanced salt solution for DMEK: a pilot study.

    Science.gov (United States)

    Gabbay, I E; Bahar, I; Nahum, Y; Livny, E

    2017-08-01

    Descemet's membrane endothelial keratoplasty (DMEK) involves removal of the recipient's Descemet membrane (DM) prior to transplanting the donor's DM. When using balanced salt solution (BSS) or ophthalmic viscosurgical devices (OVDs), visualization of the host's DM during its stripping may be inadequate and may result in Descemet remnants and could lead to sub-optimal surgical results. Previous articles described excellent visualization when utilizing air injection but this requires repeated air injection into the anterior chamber (AC). We present a pilot study that compares different techniques under which DM stripping can be performed: with continuous automated air infusion, with manual air infusion, and with BSS. We retrospectively compared video footage of DM stripping with BSS, with continuous air and with manual injection of air into the AC to determine DM stripping duration and the number of times the surgeon had to insert and retrieve a surgical instrument from the AC. Thirty videos of 10 consecutive cases of the three DM stripping techniques were evaluated. DM stripping duration was 3.26 (±1.32), 3.92 (±1.2) and 12.9 (±3.98) minutes for BSS, continuous air flow, and manual air injection, respectively. Frequency of instrument retrieval (FIR) was 3.6 (±1.71), 1.5 (±0.71) and 15.1 (±3.28) for BSS, continuous air flow, and manual air injection, respectively. Continuous air flow and BSS were both statistically different than manual air injection into the AC (p air in the AC contributes to better visualization and an efficient surgery.

  11. Improvement of Power Flow Calculation with Optimization Factor Based on Current Injection Method

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2014-01-01

    Full Text Available This paper presents an improvement in power flow calculation based on current injection method by introducing optimization factor. In the method proposed by this paper, the PQ buses are represented by current mismatches while the PV buses are represented by power mismatches. It is different from the representations in conventional current injection power flow equations. By using the combined power and current injection mismatches method, the number of the equations required can be decreased to only one for each PV bus. The optimization factor is used to improve the iteration process and to ensure the effectiveness of the improved method proposed when the system is ill-conditioned. To verify the effectiveness of the method, the IEEE test systems are tested by conventional current injection method and the improved method proposed separately. Then the results are compared. The comparisons show that the optimization factor improves the convergence character effectively, especially that when the system is at high loading level and R/X ratio, the iteration number is one or two times less than the conventional current injection method. When the overloading condition of the system is serious, the iteration number in this paper appears 4 times less than the conventional current injection method.

  12. Coupled Viscous Fluid Flow and Joint Deformation Analysis for Grout Injection in a Rock Joint

    Science.gov (United States)

    Kim, Hyung-Mok; Lee, Jong-Won; Yazdani, Mahmoud; Tohidi, Elham; Nejati, Hamid Reza; Park, Eui-Seob

    2018-02-01

    Fluid flow modeling is a major area of interest within the field of rock mechanics. The main objective of this study is to gain insight into the performance of grout injection inside jointed rock masses by numerical modeling of grout flow through a single rock joint. Grout flow has been widely simulated using non-Newtonian Bingham fluid characterized by two main parameters of dynamic viscosity and shear yield strength both of which are time dependent. The increasing value of these properties with injection time will apparently affect the parameters representing the grouting performance including grout penetration length and volumetric injection rate. In addition, through hydromechanical coupling a mutual influence between the injection pressure from the one side and the joint opening/closing behavior and the aperture profile variation on the other side is anticipated. This is capable of producing a considerable impact on grout spread within the rock joints. In this study based on the Bingham fluid model, a series of numerical analysis has been conducted using UDEC to simulate the flow of viscous grout in a single rock joint with smooth parallel surfaces. In these analyses, the time-dependent evolution of the grout fluid properties and the hydromechanical coupling have been considered to investigate their impact on grouting performance. In order to verify the validity of these simulations, the results of analyses including the grout penetration length and the injection flow rate were compared with a well-known analytical solution which is available for the simple case of constant grout properties and non-coupled hydraulic analysis. The comparison demonstrated that the grout penetration length can be overestimated when the time-dependent hardening of grout material is not considered. Moreover, due to the HM coupling, it was shown that the joint opening induced by injection pressure may have a considerable increasing impression on the values of penetration length and

  13. The efficacy of IntraFlow intraosseous injection as a primary anesthesia technique.

    Science.gov (United States)

    Remmers, Todd; Glickman, Gerald; Spears, Robert; He, Jianing

    2008-03-01

    The purpose of this study was to compare the efficacy of intraosseous injection and inferior alveolar (IA) nerve block in anesthetizing mandibular posterior teeth with irreversible pulpitis. Thirty human subjects were randomly assigned to receive either intraosseous injection using the IntraFlow system (Pro-Dex Inc, Santa Ana, CA) or IA block as the primary anesthesia method. Pulpal anesthesia was evaluated via electric pulp testing at 4-minute intervals for 20 minutes. Two consecutive 80/80 readings were considered successful pulpal anesthesia. Anesthesia success or failure was recorded and groups compared. Intraosseous injection provided successful anesthesia in 13 of 15 subjects (87%). The IA block provided successful anesthesia in 9 of 15 subjects (60%). Although this difference was not statistically significant (p = 0.2148), the results of this preliminary study indicate that the IntraFlow system can be used as the primary anesthesia method in teeth with irreversible pulpitis to achieve predictable pulpal anesthesia.

  14. An experimental study of the flow characteristics of fluidic device in a passive safety injection tank

    International Nuclear Information System (INIS)

    Cho, Seok; Song, Chul Hwa; Won, Suon Yeon; Min, Kyong Ho; Chung, Moon Ki

    1998-01-01

    It is considered to adopt passive safety injection tank (SIT) as a enhanced safety feature in KNGR. Passive SIT employs a vortex chamber as a fluidic device, which control injection flow rate passively by the variation of flow resistance produced by vortex intensity within the vortex chamber. To investigate the flow characteristics of the vortex chamber many tests have been carried out by using small-scale test facility. In this report the effects of geometric parameters of vortex chamber on discharge flow characteristics and the velocity measurement result of flow field, measured by PIV, are presented and discussed. (author). 25 refs., 11 tabs., 31 figs

  15. Selective Flow-Injection Quantification of Ultra-trace Amounts of Cr(VI) via On-line Complexation and Preconcentration with APDC Followed by Determination by Electrothermal Atomic Absorption Spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Hansen, Elo Harald

    1998-01-01

    A rapid, sensitive and selective time-based flow injection (FI) preconcentration procedure is described for the determination of ultra-trace amounts of Cr(VI) via on-line reaction with ammonium pyrrolidine dithiocarbamate (APDC) and formation of the Cr(VI)-PDC complex. The preconcentration...... to direct introduction of 55 mu l samples, yielding a detection limit (3 sigma) of 4.2 ng l(-1). The sample frequency was 21.2 samples per hour. The proposed method was evaluated by analyzing drinking water, a NIST Cr(VI)-reference material and synthetic sea water. A major contribution to successful...

  16. Preliminary three-dimensional potential flow simulation of a five-liter flask air injection experiment

    International Nuclear Information System (INIS)

    Davis, J.E.

    1977-01-01

    The preliminary results of an unsteady three-dimensional potential flow analysis of a five-liter flask air injection experiment (small-scale model simulation of a nuclear reactor steam condensation system) are presented. The location and velocity of the free water surface in the flask as a function of time are determined during pipe venting and bubble expansion processes. The analyses were performed using an extended version of the NASA-Ames Three-Dimensional Potential Flow Analysis System (POTFAN), which uses the vortex lattice singularity method of potential flow analysis. The pressure boundary condition at the free water surface and the boundary condition along the free jet boundary near the pipe exit were ignored for the purposes of the present study. The results of the analysis indicate that large time steps can be taken without significantly reducing the accuracy of the solutions and that the assumption of inviscid flow should not have an appreciable effect on the geometry and velocity of the free water surface. In addition, the computation time required for the solutions was well within acceptable limits

  17. Continuous-Flow Production of Injectable Liposomes via a Microfluidic Approach

    Science.gov (United States)

    Zizzari, Alessandra; Bianco, Monica; Perrone, Elisabetta; Amato, Francesco; Maruccio, Giuseppe; Rendina, Filippo; Arima, Valentina

    2017-01-01

    Injectable liposomes are characterized by a suitable size and unique lipid mixtures, which require time-consuming and nonstraightforward production processes. The complexity of the manufacturing methods may affect liposome solubility, the phase transition temperatures of the membranes, the average particle size, and the associated particle size distribution, with a possible impact on the drug encapsulation and release. By leveraging the precise steady-state control over the mixing of miscible liquids and a highly efficient heat transfer, microfluidic technology has proved to be an effective and direct methodology to produce liposomes. This approach results particularly efficient in reducing the number of the sizing steps, when compared to standard industrial methods. Here, Microfluidic Hydrodynamic Focusing chips were produced and used to form liposomes upon tuning experimental parameters such as lipids concentration and Flow-Rate-Ratios (FRRs). Although modelling evidenced the dependence of the laminar flow on the geometric constraints and the FRR conditions, for the specific formulation investigated in this study, the lipids concentration was identified as the primary factor influencing the size of the liposomes and their polydispersity index. This was attributed to a predominance of the bending elasticity modulus over the vesiculation index in the lipid mixture used. Eventually, liposomes of injectable size were produced using microfluidic one-pot synthesis in continuous flow. PMID:29232873

  18. Stability Analysis of High-Speed Boundary-Layer Flow with Gas Injection

    Science.gov (United States)

    2014-06-01

    laminar-turbulent transition on slender bodies in a hypersonic flow at small angles of attack is caused by amplification of acoustic waves trapped in...x decreases and slowly approaches the no-blow distribution. These CFD data demonstrate that the injection strongly affects the near-wall flow...conclusion. Figure 10 shows that the spatial growth rates ( )  are maximal for mode 0 corresponding to the Mack second mode – typical for hypersonic

  19. Theoretical considerations of Flow Injection Analysis in the Absence of Chemical Reactions

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    2000-01-01

    The fundamental mechanism of flow injection analysis (FIA) is assumed to be simple dissusion and the response of the detector is included in a model description that provide information about the shape of the FIA peak in terms of, basically, five parameters. Two of the five parameters are associa...... that any deviation from the features of the present model and the results of a tentative chemical reaction with one of the test compounds, is related to chemical kinetics.......The fundamental mechanism of flow injection analysis (FIA) is assumed to be simple dissusion and the response of the detector is included in a model description that provide information about the shape of the FIA peak in terms of, basically, five parameters. Two of the five parameters...

  20. Flow velocity effect on the corrosion/erosion in water injection systems; Efecto de la velocidad de flujo en la corrosion/erosion en sistemas de inyeccion de agua

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, C.; Mendez, J. [PDVSA Exploracion y reduccion, Departamento de Ingenieria de Instalaciones, Torres Petroleras EX-MRV, Torre Lama, Piso No. 6, Zulia, Apartado 4013, Venezuela (Venezuela)

    1998-12-31

    The main causes of fails at water injection lines on the secondary petroleum recovery systems are related with corrosion/erosion problems which are influenced by the flow velocity, the presence of dissolved oxygen, solids in the medium and the microorganisms proliferation. So too, this corrosion process promotes the suspended solids generation which affects the water quality injected, causing wells tamponage and loss of injectivity, with the consequent decrease in the crude production. This situation has been impacted in meaning order at the production processes of an exploration enterprise which utilizes the Maracaibo lake as water resource for their injection by pattern projects. Stating that, it was developed a study for determining in experimental order the effect of flow velocity on the corrosion/erosion process joined to the presence of dissolved oxygen which allows to determine the optimum range of the said working velocity for the water injection systems. This range is defined by critical velocities of bio layers deposition and erosion. They were realized simulation pilot tests of the corrosion standard variables, concentration of dissolved oxygen and fluid velocity in the injection systems with filtered and non filtered water. For the development of these tests it was constructed a device which allows to install and expose cylindrical manometers of carbon steel according to predetermined conditions which was obtained the necessary information to make correlations the results of these variables. Additionally, they were determined the mathematical models that adjusts to dynamical behavior of the corrosion/erosion process, finding the optimum range of the flow velocity for the control of this process, being necessary to utilize the following techniques: Scanning Electron Microscopy (SEM), X-ray dispersion analysis (EDX) for encourage the surface studies. They were effected morphological analysis of the surfaces studies and the values were determined of

  1. Flow injection electrochemical hydride generation inductively coupled plasma time-of-flight mass spectrometry for the simultaneous determination of hydride forming elements and its application to the analysis of fresh water samples

    International Nuclear Information System (INIS)

    Bings, Nicolas H.; Stefanka, Zsolt; Mallada, Sergio Rodriguez

    2003-01-01

    A flow injection (FI) method was developed using electrochemical hydride generation (EcHG) as a sample introduction system, coupled to an inductively coupled plasma time-of-flight mass spectrometer (ICP-TOFMS) for rapid and simultaneous determination of six elements forming hydrides (As, Bi, Ge, Hg, Sb and Se). A novel low volume electrolysis cell, especially suited for FI experiments was designed and the conditions for simultaneous electrochemical hydride generation (EcHG; electrolyte concentrations and flow rates, electrolysis voltage and current) as well as the ICP-TOFMS operational parameters (carrier gas flow rate, modulation pulse width (MPW)) for the simultaneous determination of 12 isotopes were optimized. The compromise operation parameters of the electrolysis were found to be 1.4 and 3 ml min -1 for the anolyte and catholyte flow rates, respectively, using 2 M sulphuric acid. An optimum electrolysis current of 0.7 A (16 V) and an argon carrier gas flow rate of 0.91 l min -1 were chosen. A modulation pulse width of 5 μs, which influences the sensitivity through the amount of ions being collected by the MS per single analytical cycle, provided optimum results for the detection of transient signals. The achieved detection limits were compared with those obtained by using FI in combination with conventional nebulization (FI-ICP-TOFMS); values for chemical hydride generation (FI-CHG-ICP-TOFMS) were taken from the literature. By using a 200 μl sample loop absolute detection limits (3σ) in the range of 10-160 pg for As, Bi, Ge, Hg, Sb and 1.1 ng for Se and a precision of 4-8% for seven replicate injections of 20-100 ng ml -1 multielemental sample solutions were achieved. The analysis of a standard reference material (SRM) 1643d (NIST, 'Trace Elements in Water') showed good agreement with the certified values for As and Sb. Se showed a drastic difference, which is probably due to the presence of hydride-inactive Se species in the sample. Recoveries better than

  2. Non-darcy flow behavior mean high-flux injection wells in porous and fractured formations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yu-Shu

    2003-04-25

    This paper presents a study of non-Darcy fluid flow through porous and fractured rock, which may occur near wells during high-flux injection of waste fluids into underground formations. Both numerical and analytical models are used in this study. General non-Darcy flow is described using the Forchheimer equation, implemented in a three-dimensional, multiphase flow reservoir simulator. The non-Darcy flow through a fractured reservoir is handled using a general dual continuum approach, covering commonly used conceptual models, such as double porosity, dual permeability, explicit fracture, etc. Under single-phase flow conditions, an approximate analytical solution, as an extension of the Warren-Root solution, is discussed. The objectives of this study are (1) to obtain insights into the effect of non-Darcy flow on transient pressure behavior through porous and fractured reservoirs and (2) to provide type curves for well test analyses of non-Darcy flow wells. The type curves generated include various types of drawdown, injection, and buildup tests with non-Darcy flow occurring in porous and fractured reservoirs. In addition, non-Darcy flow into partially penetrating wells is also considered. The transient-pressure type curves for flow in fractured reservoirs are based on the double-porosity model. Type curves provided in this work for non-Darcy flow in porous and fractured reservoirs will find their applications in well test interpretation using a type-curve matching technique.

  3. Development of an automated technique for the speciation of arsenic using flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS)

    Energy Technology Data Exchange (ETDEWEB)

    Ruede, T.R. (Inst. of Petrography and Geochemistry, Univ. of Karlsruhe (Germany)); Puchelt, H. (Inst. of Petrography and Geochemistry, Univ. of Karlsruhe (Germany))

    1994-09-01

    An automated method for the determination of arsenic acid (AsV), arsenous acid (AsIII), monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) was developed using a commercial available flow injection hydride generation system. By carrying out the hydride generation in selected acid media the determination of As(III) alone, of MMAA and DMAA by sum and by different sensitivities, and of all four species is possible. (orig.)

  4. Determination of the Flow Field in the Propellant Tank of a Rocket Engine on Completion of the Mission

    Science.gov (United States)

    Fedorov, A. V.; Bedarev, I. A.; Lavruk, S. A.; Trushlyakov, V. I.; Kudentsov, V. Yu.

    2018-03-01

    In the present work, a method of mathematical simulation is employed to describe processes occurring in the specimens of new equipment and using the remaining propellant in rocket-engine tanks. Within the framework of certain turbulence models, the authors perform a calculation of the flow field in the volume of the tank of the launch-vehicle stage when a hot gas jet is injected into it. A vortex flow structure is revealed; the characteristics of heat transfer for different angles of injection of the jet are determined. The obtained correlation Nu = Nu(Re) satisfactorily describes experimental data.

  5. Continuous-Flow Production of Injectable Liposomes via a Microfluidic Approach

    Directory of Open Access Journals (Sweden)

    Alessandra Zizzari

    2017-12-01

    Full Text Available Injectable liposomes are characterized by a suitable size and unique lipid mixtures, which require time-consuming and nonstraightforward production processes. The complexity of the manufacturing methods may affect liposome solubility, the phase transition temperatures of the membranes, the average particle size, and the associated particle size distribution, with a possible impact on the drug encapsulation and release. By leveraging the precise steady-state control over the mixing of miscible liquids and a highly efficient heat transfer, microfluidic technology has proved to be an effective and direct methodology to produce liposomes. This approach results particularly efficient in reducing the number of the sizing steps, when compared to standard industrial methods. Here, Microfluidic Hydrodynamic Focusing chips were produced and used to form liposomes upon tuning experimental parameters such as lipids concentration and Flow-Rate-Ratios (FRRs. Although modelling evidenced the dependence of the laminar flow on the geometric constraints and the FRR conditions, for the specific formulation investigated in this study, the lipids concentration was identified as the primary factor influencing the size of the liposomes and their polydispersity index. This was attributed to a predominance of the bending elasticity modulus over the vesiculation index in the lipid mixture used. Eventually, liposomes of injectable size were produced using microfluidic one-pot synthesis in continuous flow.

  6. Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bhandari, Deepak [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2013-01-01

    RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injection volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.

  7. Entropy Generation in a Rotating Couette Flow with Suction/Injection

    Directory of Open Access Journals (Sweden)

    S. Das

    2015-05-01

    Full Text Available The present paper is concerned with an analytical study of entropy generation in viscous incompressible Couette flow with suction/injection in a rotating frame of reference. One of the plate is held at rest and the other one moves with an uniform velocity.The flow induced by the moving plate. An exact solution of governing equations has been obtained in closed form. The entropy generation number and the Bejan number are also obtained. The influences of each of the governing parameters on velocity, temperature, entropy generation and Bejan number are discussed with the help of graphs.

  8. Enzymatic amplification of a flow-injected thermometric enzyme-linked immunoassay for human insulin.

    Science.gov (United States)

    Mecklenburg, M; Lindbladh, C; Li, H; Mosbach, K; Danielsson, B

    1993-08-01

    A flow-injected thermometric enzyme linked immunoassay for human insulin which employs the lactate dehydrogenase/lactate oxidase (LDH/LOD) substrate recycling system for signal amplification is described. The system is composed of two columns, an immunosorbent column containing immobilized anti-insulin antibodies for sensing and a recycling column containing immobilized LDH/LOD/Catalase for detection. The effect of flow rates, conjugate concentrations, and chromatographic support material upon the sensitivity of the assay are investigated. The assay has a detection limit of 0.025 microgram/ml and a linear range from 0.05 to 2 micrograms/ml. This corresponds to a 10-fold increase in sensitivity over the unamplified system. A recombinant human insulin-proinsulin conjugate was also tested. The results show that enzymatic amplification can be employed to increase the sensitivity and reproducibility of flow injection assay-based biosensors. The implications of these results upon on-line analysis are discussed.

  9. Flow injection analysis: Emerging tool for laboratory automation in radiochemistry

    International Nuclear Information System (INIS)

    Egorov, O.; Ruzicka, J.; Grate, J.W.; Janata, J.

    1996-01-01

    Automation of routine and serial assays is a common practice of modern analytical laboratory, while it is virtually nonexistent in the field of radiochemistry. Flow injection analysis (FIA) is a general solution handling methodology that has been extensively used for automation of routine assays in many areas of analytical chemistry. Reproducible automated solution handling and on-line separation capabilities are among several distinctive features that make FI a very promising, yet under utilized tool for automation in analytical radiochemistry. The potential of the technique is demonstrated through the development of an automated 90 Sr analyzer and its application in the analysis of tank waste samples from the Hanford site. Sequential injection (SI), the latest generation of FIA, is used to rapidly separate 90 Sr from interfering radionuclides and deliver separated Sr zone to a flow-through liquid scintillation detector. The separation is performed on a mini column containing Sr-specific sorbent extraction material, which selectively retains Sr under acidic conditions. The 90 Sr is eluted with water, mixed with scintillation cocktail, and sent through the flow cell of a flow through counter, where 90 Sr radioactivity is detected as a transient signal. Both peak area and peak height can be used for quantification of sample radioactivity. Alternatively, stopped flow detection can be performed to improve detection precision for low activity samples. The authors current research activities are focused on expansion of radiochemical applications of FIA methodology, with an ultimate goal of creating a set of automated methods that will cover the basic needs of radiochemical analysis at the Hanford site. The results of preliminary experiments indicate that FIA is a highly suitable technique for the automation of chemically more challenging separations, such as separation of actinide elements

  10. Coupling on-line preconcentration by ion-exchange with ETAAS. A novel flow injection approach based on the use of a renewable microcolumn as demonstrated for the determination of nickel in environmental and biological samples

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2000-01-01

    microcolumn incorporated within an integrated micro FI-system, the column is loaded with a defined volume of small beads of an SP Sephadex C-25 cation-exchange resin and subsequently exposed to a metered amount of sample solution. However, instead of eluting the retained analyte from the organic ion-exchange......A novel way of exploiting flow injection/sequential injection (FIA/SIA) on-line ion-exchange preconcentration with detection by electrothermal atomic absorption spectrometry (ETAAS) is described and demonstrated for the determination of trace-levels of nickel. Based on the use of a renewable...... resin, the beads are along with 30 mul of carrier (buffer) solution transported via air segmentation directly into the graphite tube, where they are ashed during the pyrolysis and atomization process. The ETAAS determination is performed in parallel with the preconcentration process of the ensuing...

  11. Incorporation of flow injection analysis with dual-wavelength overlapping resonance Rayleigh scattering for rapid determination of malachite green and its metabolite in fish.

    Science.gov (United States)

    Zhu, Jinghui; Qin, Mingyou; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli

    2014-09-15

    A flow injection analysis (FIA) system combined with dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) has been established and validated for rapid determination of malachite green (MG) and its metabolite in fish samples. Under experimental condition, MG would react with Erythrosin (Ery) to form ion-association complexes, resulting in the occurrence of two RRS peaks and a dramatic enhancement of RRS intensity. The maximum RRS peaks were located at 286 nm and 337 nm. It is noted that the increments of both of these two peaks were proportional to the concentration of MG. The detection limit of DWO-RRS was 1.5 ng/mL, which was comparable to several reported methods. Moreover, the results of real sample analysis exhibited an acceptable recovery between 97.5% and 103.6%, indicating that the method had good reproducibility. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Flow injection analysis of sulphide based on its photoelectrocatalytic oxidation at poly-methylene blue modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Dilgin, Yusuf; Canarslan, Seda; Ayyildiz, Onder; Ertek, Bensu; Nişli, Gürel

    2012-01-01

    A new approach for photoelectrocatalytic determination of sulphide in a flow injection analysis (FIA) system was studied using a poly-methylene blue modified glassy carbon electrode (poly-MB/GCE). Results from electrochemical measurements have revealed that poly-MB/GCE is capable of signalling electrocatalytic and photoelectrocatalytic activity towards sulphide oxidation. When the surface of poly-MB/GCE was irradiated with a light source (250 W Halogen lamp), the electrocatalytic current increased substantially. A homemade flow electrochemical cell with a suitable transparent window for the irradiation of the electrode surface was used to perform the photoelectrocatalytic determination of sulphide in FIA system. The currents obtained from the photoamperometric measurements in the FIA system at optimum conditions (carrier solution: pH 9.0 Britton Robinson buffer solution containing 0.1 M KCl; flow rate: 1.3 mL min −1 ; transmission tubing length: 10 cm; injection volume: 100 μL; and constant applied potential: +150 mV vs. Ag/AgCl/KCl sat ) were linearly correlated with the sulphide concentration. The calibration curves were obtained for sulphide concentrations in a range of 0.5–500 μM. The detection limits were found to be 0.27 and 0.15 μM for amperometric and photoamperometric methods, respectively. The proposed method was successfully applied to different wastewaters such as municipal sewage or tannery wastewater. Finally, results from the sulphide measurements by poly-MB/GCE were in good agreement with those attained using spectrophotometric method.

  13. Numerical simulation in steam injection process by a mechanistic approach

    Energy Technology Data Exchange (ETDEWEB)

    De Souza, J.C.Jr.; Campos, W.; Lopes, D.; Moura, L.S.S. [Petrobras, Rio de Janeiro (Brazil)

    2008-10-15

    Steam injection is a common thermal recovery method used in very viscous oil reservoirs. The method involves the injection of heat to reduce viscosity and mobilize oil. A steam generation and injection system consists primarily of a steam source, distribution lines, injection wells and a discarding tank. In order to optimize injection and improve the oil recovery factor, one must determine the parameters of steam flow such as pressure, temperature and steam quality. This study focused on developing a unified mathematical model by means of a mechanistic approach for two-phase steam flow in pipelines and wells. The hydrodynamic and heat transfer mechanistic model was implemented in a computer simulator to model the parameters of steam injection while trying to avoid the use of empirical correlations. A marching algorithm was used to determine the distribution of pressure and temperature along the pipelines and wellbores. The mathematical model for steam flow in injection systems, developed by a mechanistic approach (VapMec) performed well when the simulated values of pressures and temperatures were compared with the values measured during field tests. The newly developed VapMec model was incorporated in the LinVap-3 simulator that constitutes an engineering supporting tool for steam injection wells operated by Petrobras. 23 refs., 7 tabs., 6 figs.

  14. Experimental determination of sorption in fractured flow systems

    Science.gov (United States)

    Zimmerman, Mitchell D.; Bennett, Philip C.; Sharp, John M.; Choi, Wan-Joo

    2002-09-01

    Fracture "skins" are alteration zones on fracture surfaces created by a variety of biological, chemical, and physical processes. Skins increase surface area, where sorption occurs, compared to the unaltered rock matrix. This study examines the sorption of organic solutes on altered fracture surfaces in an experimental fracture-flow apparatus. Fracture skins containing abundant metal oxides, clays, and organic material from the Breathitt Formation (Kentucky, USA) were collected in a manner such that skin surface integrity was maintained. The samples were reassembled in the lab in a flow-through apparatus that simulated ˜2.7 m of a linear fracture "conduit." A dual-tracer injection scheme was utilized with the sorbing or reactive tracer compared to a non-reactive tracer (chloride) injected simultaneously. Sorption was assessed from the ratio of the first temporal moments of the breakthrough curves and from the loss of reactive tracer mass and evaluated as a function of flow velocity and solute type. The breakthrough curves suggest dual-flow regimes in the fracture with both sorbing and non-sorbing flow fields. Significant sorption occurs for the reactive components, and sorption increased with decreasing flow rate and decreasing compound solubility. Based on moment analysis, however, there was little retardation of the center of solute mass. These data suggest that non-equilibrium sorption processes dominate and that slow desorption and boundary layer diffusion cause extensive tailing in the breakthrough curves.

  15. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

    Science.gov (United States)

    Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

    2009-08-15

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  16. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Martinis, Estefania M.; Berton, Paula; Olsina, Roberto A.; Altamirano, Jorgelina C.; Wuilloud, Rodolfo G.

    2009-01-01

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 mim][PF 6 ]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 μl of 9.0 mol L -1 hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3 ng L -1 and the relative standard deviation (RSD) for 10 replicates at 1 μg L -1 Hg 2+ was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  17. Bubble-size distributions produced by wall injection of air into flowing freshwater, saltwater and surfactant solutions

    Science.gov (United States)

    Winkel, Eric S.; Ceccio, Steven L.; Dowling, David R.; Perlin, Marc

    2004-12-01

    As air is injected into a flowing liquid, the resultant bubble characteristics depend on the properties of the injector, near-wall flow, and flowing liquid. Previous research has shown that near-wall bubbles can significantly reduce skin-friction drag. Air was injected into the turbulent boundary layer on a test section wall of a water tunnel containing various concentrations of salt and surfactant (Triton-X-100, Union Carbide). Photographic records show that the mean bubble diameter decreased monotonically with increasing salt and surfactant concentrations. Here, 33 ppt saltwater bubbles had one quarter, and 20 ppm Triton-X-100 bubbles had one half of the mean diameter of freshwater bubbles.

  18. Process and part filling control in micro injection molding

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans Nørgaard; Schoth, Andreas

    2008-01-01

    The influence of process parameters on μ-injection molding (μIM) and on μ-injection molded parts has been investigated using Design of Experiments. A mold with a sensor applied at injection location was used to monitor actual injection pressure and to determine the cavity filling time. Flow markers...... position was measured on the polymer μ-parts to evaluate filling behavior of the polymer melt flowing through μ-features. Experimental results obtained under different processing conditions were evaluated to correlate the process parameter levels influence on the selected responses. Results showed...... that the injection speed in one of the most influencing process parameters on the μIM process and on the μ-parts filling....

  19. Blood flow determinations utilizing digital densitometry

    International Nuclear Information System (INIS)

    Lois, F.; Mankovich, N.J.; Gomes, A.S.

    1987-01-01

    A method of obtaining relative and absolute blood flow measurements from digital densitometry was evaluated with a simulated vessel phantom and a hydrodynamic model. A digital vascular imaging system capable of acquisition in 512 2 and 1024 2 mode was used. Relative and absolute blood flow were measured using parameters derived from the densitometric curve. Since application of densitometric data to absolute flow measurements requires the vessel diameter, an algorithm for vessel size determination was created. Gray scale changes were demonstrated to be linearly related to contrast concentration. The variance of vessel size determination was significantly different in all combinations of 1024 2 and 512 2 imaging with 15 cm or 35 cm field size. The error in vessel size determination was significantly less using the larger 1024 2 matrix and the smaller 15 cm image intensifier field size, as shown by the smaller variance. In relative flow determinations, there was good correlation between the flow and four parameters of the densitometric curve with no significant differences between 512 2 and 1024 2 imaging. Absolute flow determinations had slightly lower correlation to actual flow but were not significantly different from relative flow determinations. Relative and absolute blood flow determinations can be performed adequately with either 512 2 or 1024 2 imaging. The increased accuracy in vessel size determination with 1024 2 imaging makes this high resolution system potentially perferable to determine absolute blood flow. (orig.)

  20. Irreversibility analysis of magneto-hydrodynamic nanofluid flow injected through a rotary disk

    Directory of Open Access Journals (Sweden)

    Rashidi Mohammad Mehdi

    2015-01-01

    Full Text Available The non-linear Navier-Stokes equations governed on the nanofluid flow injected through a rotary porous disk in the presence of an external uniform vertical magnetic field can be changed to a system of non-linear partial differential equations by applying similar parameter. In this study, partial differential equations are analytically solved by the modified differential transform method, Pade differential transformation method to obtain self-similar functions of motion and temperature. A very good agreement is observed between the obtained results of Pade differential transformation method and those of previously published ones. Then it has become possible to do a comprehensive parametric analysis on the entropy generation in this case to demonstrate the effects of physical flow parameters such as magnetic interaction parameter, injection parameter, nanoparticle volume fraction, dimensionless temperature difference, rotational Brinkman number and the type of nanofluid on the problem.

  1. Flow-injection chemiluminescence assay for ultra-trace determination of DNA using rhodamine B-Ce(IV)-DNA ternary system in sulfuric acid media

    International Nuclear Information System (INIS)

    Ma Yongjun; Zhou Min; Jin Xiaoyong; Zhang Ziyu; Teng Xiulan; Chen Hui

    2004-01-01

    A novel flow-injection chemiluminescence method for the determination of DNA at ultra-trace level has been established. In 0.8 M sulfuric acid media, the chemiluminescence of the rhodamine B-cerium (IV) or Ce(IV) system is enhanced by DNA, activated previously by imidazole-HCl buffer solution (pH 7.0). The enhanced intensity of chemiluminescence is in proportion to log DNA concentration 1.0x10 -8 to 0.1 μg ml -1 for herring sperm DNA and 2.0x10 -6 to 0.2 μg ml -1 for calf thymus DNA with 3σ detection limits of 8.3x10 -9 μg ml -1 for herring sperm DNA and 3.5x10 -7 μg ml -1 for calf thymus DNA, respectively. The relative standard deviation for 1.0x10 -4 μg ml -1 herring sperm DNA was 0.99% and 2.0x10 -3 μg ml -1 for calf thymus DNA was 1.1% (n=11). Using the optimized system, DNA contents in six synthetic samples has been determined with recoveries of 99.5-109.0%. The possible mechanism has also been studied in this paper

  2. Flow-injection chemiluminescence assay for ultra-trace determination of DNA using rhodamine B-Ce(IV)-DNA ternary system in sulfuric acid media

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yongjun; Zhou Min; Jin Xiaoyong; Zhang Ziyu; Teng Xiulan; Chen Hui

    2004-01-09

    A novel flow-injection chemiluminescence method for the determination of DNA at ultra-trace level has been established. In 0.8 M sulfuric acid media, the chemiluminescence of the rhodamine B-cerium (IV) or Ce(IV) system is enhanced by DNA, activated previously by imidazole-HCl buffer solution (pH 7.0). The enhanced intensity of chemiluminescence is in proportion to log DNA concentration 1.0x10{sup -8} to 0.1 {mu}g ml{sup -1} for herring sperm DNA and 2.0x10{sup -6} to 0.2 {mu}g ml{sup -1} for calf thymus DNA with 3{sigma} detection limits of 8.3x10{sup -9} {mu}g ml{sup -1} for herring sperm DNA and 3.5x10{sup -7} {mu}g ml{sup -1} for calf thymus DNA, respectively. The relative standard deviation for 1.0x10{sup -4} {mu}g ml{sup -1} herring sperm DNA was 0.99% and 2.0x10{sup -3} {mu}g ml{sup -1} for calf thymus DNA was 1.1% (n=11). Using the optimized system, DNA contents in six synthetic samples has been determined with recoveries of 99.5-109.0%. The possible mechanism has also been studied in this paper.

  3. Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Ni [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Jiang, Shiuh-Jen, E-mail: sjjiang@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Chen, Yen-Ling [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Sahayam, A.C. [National Centre for Compositional Characterisation of Materials (CCCM), Hyderabad (India)

    2015-02-20

    Highlights: • Determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions in a single run. • Accurate analysis using isotope dilution and standard addition methods. • Vapor generation ICP-MS yielded superior detection limits compared to ETV-ICP-MS. • No sample dissolution increased sample through put. • Analysis of GBW09305 Cosmetic (Cream) reference material for accuracy. - Abstract: A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v L-cysteine, 0.5 μg mL{sup −1} Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng g{sup −1} for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample.

  4. Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions

    International Nuclear Information System (INIS)

    Chen, Wei-Ni; Jiang, Shiuh-Jen; Chen, Yen-Ling; Sahayam, A.C.

    2015-01-01

    Highlights: • Determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions in a single run. • Accurate analysis using isotope dilution and standard addition methods. • Vapor generation ICP-MS yielded superior detection limits compared to ETV-ICP-MS. • No sample dissolution increased sample through put. • Analysis of GBW09305 Cosmetic (Cream) reference material for accuracy. - Abstract: A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v L-cysteine, 0.5 μg mL −1 Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng g −1 for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample

  5. Principles and Applications of Flow Injection Analysis in Biosensors

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    1996-01-01

    In practical applications biosensors are often forced to operate under less than optimal conditions. Because of their construction, and the physical processes and chemical reactions involved in their operation, compromise conditions are frequently required to synchronize all events taking place....... Therefore, and in order to implement functions such as periodic calibration, conditioning and possible regeneration of the biosensor, and, very importantly, to yield the freedom to select the optimum detection means, it is advantageous to use these devices in a flow-through mode, particularly by employing...... the flow injection (FI) approach. The capacity of FI, as offering itself as a complementary facility to augment the performance of biosensors, and in many cases as an attractive alternative, is demonstrated by reference to selected examples, comprising assays based on enzymatic procedures with optical...

  6. MHD flow over a permeable stretching/shrinking sheet of a nanofluid with suction/injection

    Directory of Open Access Journals (Sweden)

    Sandeep Naramgari

    2016-06-01

    Full Text Available In this study we analyzed the influence of thermal radiation and chemical reaction on two dimensional steady magnetohydrodynamic flow of a nanofluid past a permeable stretching/shrinking sheet in the presence of suction/injection. We considered nanofluid volume fraction on the boundary is submissive controlled, which makes the present study entirely different from earlier studies and physically more realistic. The equations governing the flow are solved numerically. Effects of non-dimensional governing parameters on velocity, temperature and concentration profiles are discussed and presented through graphs. Also, coefficient of skin friction and local Nusselt number is investigated for stretching/shrinking and suction/injection cases separately and presented through tables. Comparisons with existed results are presented. Present results have an excellent agreement with the existed studies under some special assumptions. Results indicate that the enhancement in Brownian motion and thermophoresis parameters depreciates the nanoparticle concentration and increases the mass transfer rate. Dual solutions exist only for certain range of stretching/shrinking and suction/injection parameters.

  7. An on-line potentiometric sequential injection titration process analyser for the determination of acetic acid.

    Science.gov (United States)

    van Staden, J F; Mashamba, Mulalo G; Stefan, Raluca I

    2002-09-01

    An on-line potentiometric sequential injection titration process analyser for the determination of acetic acid is proposed. A solution of 0.1 mol L(-1) sodium chloride is used as carrier. Titration is achieved by aspirating acetic acid samples between two strong base-zone volumes into a holding coil and by channelling the stack of well-defined zones with flow reversal through a reaction coil to a potentiometric sensor where the peak widths were measured. A linear relationship between peak width and logarithm of the acid concentration was obtained in the range 1-9 g/100 mL. Vinegar samples were analysed without any sample pre-treatment. The method has a relative standard deviation of 0.4% with a sample frequency of 28 samples per hour. The results revealed good agreement between the proposed sequential injection and an automated batch titration method.

  8. Simultaneous detection of selenium by atomic fluorescence and sulfur by molecular emission by flow-injection hydride generation with on-line reduction for the determination of selenate, sulfate and sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Tyson, J.F., E-mail: tyson@chem.umass.edu [Department of Chemistry, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Palmer, C.D. [Lead Poisoning Trace Elements Laboratory, Wadsworth Center, New York State Department of Health, P.O. Box 509, Empire State Plaza, Albany, NY 12201-0509 (United States)

    2009-10-12

    An inductively coupled plasma atomic fluorescence spectrometry (ICP-AFS) instrument, was modified so that it was capable of monitoring transient chromatographic or flow-injection profiles and that sulfur molecular emission and selenium atomic fluorescence could be monitored simultaneously in an argon-hydrogen diffusion flame on a glass burner. The analytes were introduced as hydrogen selenide and hydrogen sulfide, generated on a flow-injection manifold. Selenate was reduced to hydride-forming selenite by microwave-assisted on-line reaction with hydrochloric acid, and sulfate, or sulfite, was reduced to hydride-forming sulfide by a mixture of hydriodic acid, acetic acid and sodium hypophosphite. The effects of the nature of reducing agent, flow rate, microwave power and coil length were studied. The limit of detection (3 s) for selenium was 10 {mu}g L{sup -1}, and for sulfide was 70 {mu}g L{sup -1} (200-{mu}L injection volume). The calibration was linear for selenium up to 2 mg L{sup -1} and to 10 mg L{sup -1} for sulfide. The throughput was 180 h{sup -1}. The three sulfur species could be differentiated on the basis of reactivity at various microwave powers.

  9. Flow visualization and simulation of the filling process during injection molding

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Tosello, Guido; Hattel, Jesper Henri

    2017-01-01

    To directly compare experimental moldings from an injection molding machine with simulations, a special mold has been produced with a glass window. The injection plane is perpendicular to the opening and closing planes, in order for the 55. mm thick glass window to be easily visible from the side....... These two had significant effects on the filling times and injection pressure calculated by the simulations. Other effects investigated included transient thermal management of the mold, pressure dependent viscosity and wall slip, but their effect were not remarkably large in this work. The obtained....... A high speed camera recording 500 frames per second was employed, and the mold had three thermocouples and two pressure sensors installed. The molded part is a 2. mm thick plate with a 0.5. mm thin section, which creates a characteristic V-shaped flow pattern. Two different materials were employed...

  10. Three-dimensional simulation of flow and combustion for pulverised coal injection

    Energy Technology Data Exchange (ETDEWEB)

    Guo, B.Y.; Zulli, P.; Rogers, H.; Mathieson, J.G.; Yu, A.B. [BlueScope Steel Research, Port Kembla, NSW (Australia)

    2005-07-01

    A three-dimensional numerical model of pulverised coal injection has been developed for simulating coal flow and combustion in the tuyere and raceway of a blast furnace. The model has been used to simulate previously reported combustion tests, which feature an inclined co-axial lance with an annular cooling gas. The predicted coal burnout agrees well with that measured for three coals with volatile contents and particle size ranging between 20.2-36.4% and particle sizes 1-200 {mu}m. Many important phenomena including flow asymmetry, recirculating flow and particle dispersion in the combustion chamber have been predicted. The current model can reproduce the experimental observations including the effects on burnout of coal flowrate and the introduction of methane for lance cooling.

  11. Numerical simulation of effects of a non-ionized fluid injection and suction on the MHD flow in a circular channel

    International Nuclear Information System (INIS)

    Rahimi Eosboee, M.; Pourmahmoud, N.; Mirzaie, I.; Mohajeri Khameneh, P.; Majidyfar, S.

    2012-01-01

    Control of a fluid flow velocity profile by injection and suction of a non-ionized fluid in presence of a uniform steady magnetic field has important technical applications. In this paper, the unsteady incompressible and viscous conducting fluid flow has been investigated in a circular channel. The channel walls are assumed to be non-conducting and porous. They are subjected to a uniform steady magnetic field which is perpendicular to the axis of channel, then and suction and injection are applied at the walls. The well known equations of Magnetohydrodynamics are governed to the motion of an electrically conducting fluid flow that is subjected to magnetic field. The numerical solution is carried out by finite difference approach. The results of present numerical simulation shown that the flow injection and suction through the wall can be controlled effectively, the main flow in channel especially in industrial purposes. The results are obtained for different values of the injected and sucked non-ionized flow rate and the effect of Hartman number on the velocity profile is investigated. Finally, a good agreement is seen between the presented results and the corresponding data of finite element method.

  12. Dispersion-convolution model for simulating peaks in a flow injection system.

    Science.gov (United States)

    Pai, Su-Cheng; Lai, Yee-Hwong; Chiao, Ling-Yun; Yu, Tiing

    2007-01-12

    A dispersion-convolution model is proposed for simulating peak shapes in a single-line flow injection system. It is based on the assumption that an injected sample plug is expanded due to a "bulk" dispersion mechanism along the length coordinate, and that after traveling over a distance or a period of time, the sample zone will develop into a Gaussian-like distribution. This spatial pattern is further transformed to a temporal coordinate by a convolution process, and finally a temporal peak image is generated. The feasibility of the proposed model has been examined by experiments with various coil lengths, sample sizes and pumping rates. An empirical dispersion coefficient (D*) can be estimated by using the observed peak position, height and area (tp*, h* and At*) from a recorder. An empirical temporal shift (Phi*) can be further approximated by Phi*=D*/u2, which becomes an important parameter in the restoration of experimental peaks. Also, the dispersion coefficient can be expressed as a second-order polynomial function of the pumping rate Q, for which D*(Q)=delta0+delta1Q+delta2Q2. The optimal dispersion occurs at a pumping rate of Qopt=sqrt[delta0/delta2]. This explains the interesting "Nike-swoosh" relationship between the peak height and pumping rate. The excellent coherence of theoretical and experimental peak shapes confirms that the temporal distortion effect is the dominating reason to explain the peak asymmetry in flow injection analysis.

  13. On-line determination of glucose and lactate concentrations in animal cell culture based on fibre optic detection of oxygen in flow-injection analysis.

    Science.gov (United States)

    Dremel, B A; Li, S Y; Schmid, R D

    1992-01-01

    A flow-injection analysis (FIA) system based on fibre optic detection of oxygen consumption using immobilized glucose oxidase (GOD) and lactate oxidase (LOD) is described for the on-line monitoring of glucose and lactate concentrations in animal cell cultures. The consumption of oxygen was determined via dynamic quenching by molecular oxygen of the fluorescence of an indicator. GOD and LOD were immobilized on controlled pore glass (CPG) in enzyme reactors which were directly linked to a specially designed fibre optic flow-through cell covering the oxygen optrode. The system is linear for 0-30 mM glucose, with an r.s.d. of 5% at 30 mM (five measurements) and for 0-30 mM lactate, with an r.s.d. of 5% at 30 mM (five measurements). The enzyme reactors used were stable for more than 4 weeks in continuous operation, and it was possible to analyse up to 20 samples per hour. The system has been successfully applied to the on-line monitoring of glucose and lactate concentrations of an animal cell culture designed for the production of recombinant human antithrombine III (AT-III). Results of the on-line measurement obtained by the FIA system were compared with the off-line results obtained by a glucose and lactate analyser from Yellow Springs Instrument Company (YSI).

  14. Single injection techniques in determining age-related changes in porcine renal function

    International Nuclear Information System (INIS)

    Robbins, M.E.C.

    1984-01-01

    Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were determined in 32 anaesthetised female Large White pigs, aged 4-24 months, from the plasma disappearance curves of [sup(99m)Tc]DTPA and [ 131 I]hippuran respectively. Clearance was also monitored by external counting over the heart. GFR and ERPF increased markedly with age in pigs up to 12 months old, reaching mean values of 242.06 +- 5.89 and 919.39 +- 79.01 mL/min. In pigs aged 12-24 months ERPF increased slightly but renal function remained essentially unchanged after 1 yr of age. These results for renal function were similar to previous estimates, using continuous infusion techniques inferring that GFR and ERPF could be accurately monitored using single injection procedures. (author)

  15. Determination of technetium-99, thorium-230 and uranium-234 in soils by inductively coupled plasma mass spectrometry using flow injection preconcentration

    International Nuclear Information System (INIS)

    Hollenbach, Mark; Grohs, James; Mamich, Stephen; Kroft, Marilyn; Denoyer, E.R.

    1994-01-01

    A new method is described for the determination of 99 Tc, 230 Th, and 234 U at ultra-trace levels in soils. The method used flow injection (FI) for on-line preconcentration of 99 Tc, 230 Th and 234 U prior to detection using inductively coupled plasma mass spectrometry (ICP-MS). The FI-ICP-MS method results in greater sensitivity and freedom from interferences compared with direct aspiration into an ICP mass spectrometer. Detection limits are improved by approximately a factor of 10. The FI-ICP-MS method is also faster, less labour intensive and generates less laboratory waste than traditional radiochemical methods. The accuracy of the method was tested for 99 Tc by comparison to liquid scintillation counting and for 230 Th and 234 U by analysis of a US Department of Energy reference soil. Detection limits in the soil for 99 Tc, 230 Th and 234 U were 11 mBq g -1 (0.02 ng g -1 ), 3.7 mBq g -1 (0.005 ng g -1 ) and 0.74 mBq g -1 (0.003 ng g -1 ), respectively. Sample preparation, analysis protocol, and method validation are described. (Author)

  16. Highly sensitive determination of diclofenac based on resin beads and a novel polyclonal antibody by using flow injection chemiluminescence competitive immunoassay

    Science.gov (United States)

    Shi, Jing; Xu, Mingxia; Tang, Qinghui; Zhao, Kang; Deng, Anping; Li, Jianguo

    2018-02-01

    A novel flow injection chemiluminescence immunoassay for simple, sensitive and low-cost detection of diclofenac was established based on specific binding of antigen and antibody. Carboxylic resin beads used as solid phase carrier materials provided good biocompatibility and large surface-to-volume ratio for modifying more coating antigen. There was a competitive process between the diclofenac in solution and the immobilized coating antigen to react with the limited binding sites of the polyclonal antibody to form the immunocomplex. The second antibody labelled with horseradish peroxidase was introduced into the immunosensor and trapped by captured polyclonal antibody against diclofenac, which could effectively amplify chemiluminescence signals of luminol-PIP-H2O2. Under optimal conditions, the diclofenac could be detected quantitatively. The chemiluminescence intensity decreased linearly with the logarithm of the diclofenac concentration in the range of 0.1-100 ng mL- 1 with a detection limit of 0.05 ng mL- 1 at a signal-to-noise ratio of 3. The immunosensor exhibited high sensitivity, specificity and acceptable stability. This easy-operated and cost-effective analytical method could be valuable for the diclofenac determination in real water samples.

  17. Theoretical Study on the Flow of Refilling Stage in a Safety Injection Tank

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Sang [Halla Univ. Daejeon (Korea, Republic of)

    2017-10-15

    In this study, a theoretical analysis was performed to the flow of refilling stage in a safety injection tank, which is the core cooling system of nuclear power plant in an emergency. A theoretical model was proposed with a nonlinear governing equation defining on the flow of the refilling process of the coolant. Utilizing the Taylor-series expansion, the 1st - order approximation flow equation was obtained, along with its analytic solution of closed type, which could predict accurately the variations of free surface height and flow rate of the coolant. The availability of theoretical result was confirmed by comparing with previous experimental results.

  18. AN APPLICATION OF FLOW INJECTION ANALYSIS WITH GAS DIFFUSION AND SPECTROPHOTOMETRIC DETECTION FOR THE MONITORING OF DISSOLVED SULPHIDE CONCENTRATION IN ENVIRONMENTAL SAMPLES

    Directory of Open Access Journals (Sweden)

    Malwina Cykowska

    2014-10-01

    Full Text Available The monitoring of the concentration of sulphide is very important from the environment point of view because of high toxicity of hydrogen sulphide. What is more hydrogen sulphide is an important pollution indicator. In many cases the determination of sulphide is very difficult due to complicated matrix of some environmental samples, which causes that most analytical methods cannot be used. Flow injection analysis allows to avoid matrix problem what makes it suitable for a wide range of applications in analytical laboratories. In this paper determination of dissolved sulphide in environmental samples by gas-diffusion flow injection analysis with spectrophotometric detection was presented. Used gas-diffusion separation ensures the elimination of interferences caused by sample matrix and gives the ability of determination of sulphides in coloured and turbid samples. Studies to optimize the measurement conditions and to determine the value of the validation parameters (e.g. limit of detection, limit of quantification, precision, accuracy were carried out. Obtained results confirm the usefulness of the method for monitoring the concentration of dissolved sulphides in water and waste water. Full automation and work in a closed system greatly reduces time of analysis, minimizes consumption of sample and reagents and increases safety of analyst’s work.

  19. Determination of the separate effective renal blood flow by mathematical interpretation of radionephrograms

    International Nuclear Information System (INIS)

    Degtereva, O.A.; Zvonova, I.A.

    1982-01-01

    Mathematical model of nephrotropic compound kinetics was plotted, and using +t, the procedure of determination of separate effective, renal blood flow was developed. This procedure was based on radionephrograms obtained after intravenous injection of 131 I hippuran. Partial renal functions were found according summary gammachronograms of the precardiac and renal areas with double taking of blood samples. The technique of plotting of theoretical summary radionephrogram was solved according to calculated parameters [ru

  20. A dilute-and-shoot flow-injection tandem mass spectrometry method for quantification of phenobarbital in urine.

    Science.gov (United States)

    Alagandula, Ravali; Zhou, Xiang; Guo, Baochuan

    2017-01-15

    Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is the gold standard of urine drug testing. However, current LC-based methods are time consuming, limiting the throughput of MS-based testing and increasing the cost. This is particularly problematic for quantification of drugs such as phenobarbital, which is often analyzed in a separate run because they must be negatively ionized. This study examined the feasibility of using a dilute-and-shoot flow-injection method without LC separation to quantify drugs with phenobarbital as a model system. Briefly, a urine sample containing phenobarbital was first diluted by 10 times, followed by flow injection of the diluted sample to mass spectrometer. Quantification and detection of phenobarbital were achieved by an electrospray negative ionization MS/MS system operated in the multiple reaction monitoring (MRM) mode with the stable-isotope-labeled drug as internal standard. The dilute-and-shoot flow-injection method developed was linear with a dynamic range of 50-2000 ng/mL of phenobarbital and correlation coefficient > 0.9996. The coefficients of variation and relative errors for intra- and inter-assays at four quality control (QC) levels (50, 125, 445 and 1600 ng/mL) were 3.0% and 5.0%, respectively. The total run time to quantify one sample was 2 min, and the sensitivity and specificity of the method did not deteriorate even after 1200 consecutive injections. Our method can accurately and robustly quantify phenobarbital in urine without LC separation. Because of its 2 min run time, the method can process 720 samples per day. This feasibility study shows that the dilute-and-shoot flow-injection method can be a general way for fast analysis of drugs in urine. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Numerical simulation of the gas-solid flow in a square circulating fluidized bed with secondary air injection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhengyang [Harbin Institute of Technology, Harbin (China). Post-doctor Station of Civil Engineering; Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Sun, Shaozeng; Zhao, Ningbo; Wu, Shaohua [Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Tan, Yufei [Harbin Institute of Technology, Harbin (China). School of Municipal and Environmental Engineering

    2013-07-01

    The dynamic behavior of gas-solid flow in an experimental square circulating fluidized bed setup (0.25 m x 0.25 m x 6.07 m) is predicted with numerical simulation based on the theory of Euler-Euler gas-solid two-phase flow and the kinetic theory of granular flows. The simulation includes the operation cases with secondary injection and without air-staging. The pressure drop profile, local solids concentration and particle velocity was compared with experimental results. Both simulation and experimental results show that solids concentration increases significantly below the secondary air injection ports when air-staging is adopted. Furthermore, the flow asymmetry in the solid entrance region of the bed was investigated based on the particle concentration/velocity profile. The simulation results are in agreement with the experimental results qualitatively.

  2. Flow Injection Analysis of Mercury Using 4-(Dimethylamino Benzaldehyde-4-Ethylthiosemicarbazone as the Ionophore of a Coated Wire Electrode

    Directory of Open Access Journals (Sweden)

    Sulaiman Ab Ghani

    2012-11-01

    Full Text Available A flow injection analysis (FIA incorporating a thiosemicarbazone-based coated wire electrode (CWE was developed method for the determination of mercury(II. A 0.1 M KNO3 carrier stream with pH between 1 and 5 and flow rate of 1 mL·min−1 were used as optimum parameters. A linear plot within the concentration range of 5 × 10−6–0.1 M Hg(II, slope of 27.8 ± 1 mV per decade and correlation coefficient (R2 of 0.984 were obtained. The system was successfully applied for the determination of mercury(II in dental amalgam solutions and spiked environmental water samples. Highly reproducible measurements with relative standard deviation (RSD < 1% (n = 3 were obtained, giving a typical throughput of 30 samples·h−1.

  3. Numerical simulation of flow characteristics of lean jet to cross-flow in safety injection of reactor cooling system

    International Nuclear Information System (INIS)

    Wang Haijun; He Huining; Luo Yushan; Wang Weishu

    2011-01-01

    In the present work, a numerical simulation was performed to study the flow characteristics of lean jet to cross flow in a main tube in the safety injection of reactor cooling system. The influence scope and mixing characteristics of the confined lean jet in cross-flow were studied. It can be concluded that three basic flow regimes are marked, namely the attached lean jet, lift-off lean jet and impinging lean jet. The velocity ratio V R is the key factor in the flow state. The depth and region of jet to main flow are enhanced with the increase of the velocity ratio. The jet flow penetrates through the main flow with the increase of the velocity ratio. At higher velocity ratio, the jet flow strikes the main flow bottom and circumfluence happens in upriver of main flow. The vortex flow characteristics dominate the flow near region of jet to cross-flow and the mixture of jet to cross-flow. At different velocity ratio V R , the vortex grows from the same displacement, but the vortex type and the vortex is different. At higher velocity ratio, the vortex develops fleetly, wears off sharp and dies out sharp. The study is very important to the heat transfer experiments of cross-flow jet and thermal stress analysis in the designs of nuclear engineering. (authors)

  4. A study on nozzle flow and spray characteristics of piezo injector for next generation high response injection

    International Nuclear Information System (INIS)

    Lee, Jin Wook; Min, Kyoung Doug

    2006-01-01

    Most diesel injector, which is currently used in high-pressure common rail fuel injection system of diesel engine, is driven by the solenoid coil energy for its needle movement. The main disadvantage of this solenoid-driven injector is a high power consumption, high power loss through solenoid coil and relatively fixed needle response's problem. In this study, a prototype piezo-driven injector, as a new injector mechanism driven by piezoelectric energy based on the concept of inverse piezo-electric effect, has been designed and fabricated to know the effect of piezo-driven injection processes on the diesel spray structure and internal nozzle flow. Firstly we investigated the spray characteristics in a constant volume chamber pressurized by nitrogen gas using the back diffusion light illumination method for high-speed temporal photography and also analyzed the inside nozzle flow by a fully transient simulation with cavitation model using VOF(Volume Of Fraction) method. The numerical calculation has been performed to simulate the cavitating flow of 3-dimensional real size single hole nozzle along the injection duration. Results were compared between a conventional solenoid-driven injector and piezo-driven injector, both equipped with the same micro-sac multi-hole injection nozzle. The experimental results show that the piezo-driven injector has short injection delay and a faster spray development and produces higher injection velocity than the solenoid-driven injector. And the predicted simulation results with the degree of cavitation's generation inside nozzle for faster needle response in a piezo-driven injector were reflected to spray development in agreement with the experimental spray images

  5. [Studies on a sequential injection renewable surface reflectance spectrophotometric system using a microchip flow cell].

    Science.gov (United States)

    Wang, Jian-ya; Fang, Zhao-lun

    2002-02-01

    A microchip flow cell was developed for flow injection renewable surface assay by reflectance spectrophotometry. The flow cell was coupled to a sequential injection system and optical fiber photometric detection system. The flow cell featured a three-layer structure. The flow channel was cut into a silicone rubber membrance which formed the middle layer, and a porous filter was inlayed across a widened section of the channel to trap microbeads introduced into the flow cell. The area of the detection window of the flow cell was approximately 3.6 mm2, the volume of the bead trapped in the flow cell was 2.2 microL, the depth of the bead layer was 600 microns. A multistrand bifurcated optical fiber was coupled with incident light, detector and flow cell. The chromogenic reaction of Cr(VI) with 1,5-diphenylcarbohydrazide (DPC) which was adsorbed on trapped Polysorb C-18 beads was used as a model reaction to optimize the flow cell design and the experimental system. The reflectance of the renewable reaction surface was monitored at 540 nm. With 100 microL sample loaded and 1.0 mL.min-1 carrier flow rate, the linear response range was 0-0.6 microgram.mL-1 Cr(VI). A detection limit (3 sigma) of 6 ng.mL-1, precision of 1.5% RSD(n = 11), and a throughput of 64 samples per hour were achieved. Considerations in system and flow cell design, the influence of depth of the bead layer, weight of beads used, and the flow rates of carrier stream on the performance were discussed.

  6. Magnetohydrodynamics effect on three-dimensional viscous incompressible flow between two horizontal parallel porous plates and heat transfer with periodic injection/suction

    Directory of Open Access Journals (Sweden)

    R. C. Chaudhary

    2004-11-01

    Full Text Available We investigate the hydromagnetic effect on viscous incompressible flow between two horizontal parallel porous flat plates with transverse sinusoidal injection of the fluid at the stationary plate and its corresponding removal by periodic suction through the plate in uniform motion. The flow becomes three dimensional due to this injection/suction velocity. Approximate solutions are obtained for the flow field, the pressure, the skin-friction, the temperature field, and the rate of heat transfer. The dependence of solution on M (Hartmann number and λ (injection/suction is investigated by the graphs and tables.

  7. Determination of phenols by flow injection and liquid chromatography with on-line quinine-sensitized photo-oxidation and quenched luminol chemiluminescence detection

    International Nuclear Information System (INIS)

    Zhang Wei; Danielson, Neil D.

    2003-01-01

    An on-line quinine-sensitized photo-oxidation with quenched chemiluminescence (CL) detection method is developed for phenols using flow injection (FI) and liquid chromatography (LC). This detection method is based on the decrease of light emission from the luminol CL reaction due to the photo-oxidation of phenols that scavenge the photogenerated reactive oxygen species (e.g. singlet oxygen ( 1 O 2 ) and superoxide (O 2 · - )). On-line photo-oxidation is achieved using a coil photo-reactor made from fluoroethylene-propylene copolymer tubing (3048 mmx0.25 mm i.d.) coiled around a mercury UV lamp. A buffer of pH 7 and a concentration of 350 μM for quinine sulfate are determined optimum for the sensitized photo-oxidation. Using a carrier system flow rate of 60 μl/min, calibration curves taken by FI for 10 phenolic compounds in aqueous solutions showed this decreasing sensitivity order: 4-chlorophenol, phenol, 4-nitrophenol, 3-hydroxy-L-kynurenine, 2-nitrophenol, salicylate, 3-nitrophenol, catechol, 2,4-dinitrophenol, and 2,4-dichlorophenol. This detection method using two tandem coil photo-reactors is also applied for the LC separation of phenol, 4-nitrophenol and 4-chlorophenol on an octadecyl (C18) silica LC column using acetonitrile-H 2 O (40:60, v/v) as a mobile phase. The quenched CL detection limits (about 1 μM or 20 pmol) for phenol and 4-chlorophenol are comparable to those for UV detection at 254 nm. Some selectivity in the quenched CL detection is evident by no interference in the FI phenol response even when benzaldehyde and phenethanol concentrations are 8 and 15 times that of phenol

  8. Exact solution for flow in a porous pipe with unsteady wall suction and/or injection

    Science.gov (United States)

    Tsangaris, S.; Kondaxakis, D.; Vlachakis, N. W.

    2007-10-01

    This paper presents an extension of the exact solution of the steady laminar axisymmetric flow in a straight pipe of circular cross section with porous wall, given by R.M. Terrill, to the case of unsteady wall injection and/or suction. The cases of the pulsating parabolic profile and of the developed pulsating flow are investigated as examples. The pulsating flow in porous ducts has many applications in biomedical engineering and in other engineering areas.

  9. Flow Injection and Atomic Absorption Spectrometry - An Effective and Attractive Analytical Chemical Combination

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Nielsen, Steffen

    1998-01-01

    One of the advantages of the flow injection (FI) concept is that it is compatible with virtually all detection techniques. Being a versatile vehicle for enhancing the performance of the individual detection devices, the most spectacular results have possibly been obtained in conjunction with atom...

  10. AAO-CNTs electrode on microfluidic flow injection system for rapid iodide sensing.

    Science.gov (United States)

    Phokharatkul, Ditsayut; Karuwan, Chanpen; Lomas, Tanom; Nacapricha, Duangjai; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2011-06-15

    In this work, carbon nanotubes (CNTs) nanoarrays in anodized aluminum oxide (AAO-CNTs) nanopore is integrated on a microfluidic flow injection system for in-channel electrochemical detection of iodide. The device was fabricated from PDMS (polydimethylsiloxane) microchannel bonded on glass substrates that contains three-electrode electrochemical system, including AAO-CNTs as a working electrode, silver as a reference electrode and platinum as an auxiliary electrode. Aluminum, stainless steel catalyst, silver and platinum layers were sputtered on the glass substrate through shadow masks. Aluminum layer was then anodized by two-step anodization process to form nanopore template. CNTs were then grown in AAO template by thermal chemical vapor deposition. The amperometric detection of iodide was performed in 500-μm-wide and 100-μm-deep microchannels on the microfluidic chip. The influences of flow rate, injection volume and detection potential on the current response were optimized. From experimental results, AAO-CNTs electrode on chip offers higher sensitivity and wider dynamic range than CNTs electrode with no AAO template. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Sahin, Cigdem Arpa; Tokgoez, Ilknur

    2010-01-01

    A rapid, simple and cost effective solidified floating organic drop microextraction (SFODME) and flow injection flame atomic absorption spectrometric determination (FI-FAAS) method for copper was developed. In this method, a free microdrop of 1-undecanol containing 1,5-diphenyl carbazide (DPC) as the complexing agent was transferred to the surface of an aqueous sample including Cu(II) ions, while being agitated by a stirring bar in the bulk of the solution. Under the proper stirring conditions, the suspended microdrop can remain at the top-center position of the aqueous sample. After the completion of the extraction, the sample vial was cooled by placing it in a refrigerator for 10 min. The solidified microdrop was then transferred into a conical vial, where it melted immediately and diluted to 300 μL with ethanol. Finally, copper ions in 200 μL of diluted solution were determined by FI-FAAS. Several factors affecting the microextraction efficiency, such as type of extraction solvent, pH, complexing agent concentration, extraction time, stirring rate, sample volume and temperature were investigated and optimized. Under optimized conditions for 100 mL of solution, the preconcentration factor was 333 and the enrichment factor was 324. The limit of detection (3 s) was 0.4 ng mL -1 , the limit of quantification (10 s) was 1.1 ng mL -1 and the relative standard deviation (RSD) for 10 replicate measurements of 10 ng mL -1 copper was 0.9%. The proposed method was successfully applied to the determination of copper in different water samples.

  12. Determination of arsenic species in human urine using HPLC with on-line photooxidation or microwave-assisted oxidation combined with flow-injection HG-AAS

    Energy Technology Data Exchange (ETDEWEB)

    Sur, R.; Begerow, J.; Dunemann, L. [Department of Analytical Chemistry, Medizinisches Institut fuer Umwelthygiene, Duesseldorf (Germany)

    1999-03-01

    An improved analytical procedure is presented for the separation and simultaneous determination of hydride-forming (toxic) and not hydride-forming (non-toxic) arsenic species in human urine. Separation was performed by cation-exchange chromatography using a new solid phase type based on the continuous bed chromatography (CBC) technology. This column permits by a factor of 4 higher flow rates than conventional columns resulting in a drastical reduction of retention times without any loss of resolution. Using this type of column, arsenobetaine (AsBet), arsenocholine (AsChol), and dimethylarsinic acid (DMA) were separated from the more toxic arsenic species arsenous acid (As(III)), arsenic acid (As(V)), and methylarsonic acid (MA) within only 4 min. The HPLC system was coupled via a flow injection system and either a UV or a microwave (MW) reactor to the HG-AAS instrument. UV photolysis and MW digestion were used to transform AsBet and AsChol to hydride-forming species and to make them accessible to HG-AAS. UV photolysis turned out to be more suitable for this application than MW digestion, because the latter technique led to peak broadening and poorer performance. The described procedure was applied to the determination of arsenic species in urine samples of non-occupationally exposed persons before and 12 h after seafood consumption. Detection limits were about 1 {mu}g/L for each arsenic species. After consumption, the AsBet and DMA excretion increased by at least a factor of 150 for AsBet and by a factor of 6 for DMA, respectively, while the excretion of the other species did not increase significantly. This invalidates the use of total urinary arsenic as well as total hydride-forming arsenic as an indicator for exposure to inorganic arsenic. (orig.) With 4 figs., 2 tabs., 13 refs.

  13. Flow Injection Photosensitized Chemiluminescence of Luminol with Cu(II-Rose Bengal: Mechanistic Approach and Vitamin A and C Determination

    Directory of Open Access Journals (Sweden)

    Muhammad Asgher

    2014-01-01

    Full Text Available Rose Bengal photosensitized flow injection chemiluminescence method is reported using luminol-Cu(II for the determination of vitamins A and C in pharmaceutical formulations. The reaction is based on the enhancement effect of analyte in the production of anion radicals of Rose Bengal (RB•− which rapidly interact with dissolved oxygen and generate superoxide anions radicals (O2•− and hydrogen peroxide (H2O2. Highly reactive hydroxyl radicals (•OH were produced via dismutation of H2O2 by catalyst (Cu2+. The generated superoxide anions radicals and hydroxyl radicals thus oxidize luminol in alkaline medium to generate strong chemiluminescence. The limit of detection (3s of the blank, n=6 of vitamins A and C and RB was found to be 0.008, 0.005, and 0.05 μg mL−1, respectively. The sample throughput of 70 h−1 for vitamins A and C and 30 h−1 for RB was found. Calibration curve was linear in the range of 0.05–15, 0.01–20, and 0.1–50 μg mL−1 for vitamins A and C and RB, respectively, with relative standard deviations (RSDs; n=3 in the range 1.6–3.6%. The method was successfully applied to pharmaceutical formulations and the results obtained were in good agreement with the labeled values.

  14. Determination of thiomersal by flow injection coupled with microwave-assisted photochemical online oxidative decomposition of organic mercury and cold vapor atomic fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Campanella, Beatrice; Onor, Massimo; Mascherpa, Marco Carlo; D’Ulivo, Alessandro; Ferrari, Carlo; Bramanti, Emilia

    2013-01-01

    Graphical abstract: -- Highlights: •Thiomersal was determined on line using FI-MW/UV-CVGAFS. •MW/UV allows a “green” on line oxidation of organic mercury to Hg II . •Each measure requires less than 5 min with a LOD of 3 ng mL −1 (as mercury). •Hg concentration in commercial ophthalmic solutions ranges between 7.5 and 59.0 μg mL −1 . -- Abstract: We developed a flow injection (FI) method for the determination of thiomersal (sodium ethylmercurithiosalicylate, C 9 H 9 HgNaO 2 S) based on the UV/microwave (MW) photochemical, online oxidation of organic mercury, followed by cold vapor generation atomic fluorescence spectrometry (CVG-AFS) detection. Thiomersal was quantitatively converted in the MW/UV process to Hg(II), with a yield of 97 ± 3%. This reaction was followed by the reduction of Hg(II) to Hg(0) performed in a knotted reaction coil with NaBH 4 solution, and AFS detection in an Ar/H 2 miniaturized flame. The method was linear in the 0.01–2 μg mL −1 range, with a LOD of 0.003 μg mL −1 . This method has been applied to the determination of thiomersal in ophthalmic solutions, with recoveries ranging between 97% and 101%. We found a mercury concentration in commercial ophthalmic solutions ranging between 7.5 and 59.0 μg mL −1

  15. Determination of picloram in natural waters employing sequential injection square wave voltammetry using the hanging mercury drop electrode.

    Science.gov (United States)

    Dos Santos, Luciana B O; Masini, Jorge C

    2007-05-15

    This paper describes the development of a sequential injection analysis method to automate the determination of picloram by square wave voltammetry exploiting the concept of monosegmented flow analysis to perform in-line sample conditioning and standard addition. To perform these tasks, an 800muL monosegment is formed, composed by 400muL of sample and 400muL of conditioning/standard solution, in medium of 0.10molL(-1) H(2)SO(4). Homogenization of the monosegment is achieved by three flow reversals. After homogenization the mixture zone is injected toward the flow cell, which is adapted to the capillary of a hanging drop mercury electrode, at a flow rate of 50muLs(-1). After a suitable delay time, the potential is scanned from -0.5 to -1.0V versus Ag/AgCl at frequency of 300Hz and pulse height of 25mV. The linear dynamic range is observed for picloram concentrations between 0.10 and 2.50mgL(-1) fitting to the linear equation I(p)=(-2.19+/-0.03)C(picloram)+(0.096+/-0.039), with R(2)=0.9996, for which the slope is given in muALmg(-1). The detection and quantification limits are 0.036 and 0.12mgL(-1), respectively. The sampling frequency is 37h(-1) when the standard addition protocol is followed, but can be increased to 41h(-1) if the protocol to obtain in-line external calibration curve is used for quantification. The method was applied for determination of picloram in spiked water samples and the accuracy was evaluated by comparison with high performance liquid chromatography using molecular absorption at 220nm for detection. No evidences of statistically significant differences between the two methods were observed.

  16. Numerical Simulation of Magnetic Nanoparticles Injection into Two–phase Flow in a Porous Medium

    KAUST Repository

    El-Amin, Mohamed; Saad, Ahmed M.; Sun, Shuyu; Salama, Amgad

    2017-01-01

    In this paper, the problem of magnetic nanoparticles injection into a water–oil two–phase flow under an external permanent magnetic field is investigated. The mathematical model of the problem under consideration has been developed. We treat

  17. Quantum dots as chemiluminescence enhancers tested by sequential injection technique: Comparison of flow and flow-batch conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sklenářová, Hana, E-mail: sklenarova@faf.cuni.cz [Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Department of Analytical Chemistry, Hradec Králové (Czech Republic); Voráčová, Ivona [Institute of Analytical Chemistry of the CAS, v. v. i., Brno (Czech Republic); Chocholouš, Petr; Polášek, Miroslav [Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Department of Analytical Chemistry, Hradec Králové (Czech Republic)

    2017-04-15

    The effect of 0.01–100 µmol L{sup −1} Quantum Dots (QDs) with different emission wavelengths (520–640 nm) and different surface modifications (mercaptopropionic, mercaptoundecanoic, thioglycolic acids and mercaptoethylamine) on permanganate-induced and luminol–hydrogen peroxide chemiluminescence (CL) was studied in detail by a sequential injection technique using a spiral detection flow cell and a flow-batch detection cell operated in flow and stop-flow modes. In permanganate CL system no significant enhancement of the CL signal was observed while for the luminol–hydrogen peroxide CL substantial increase (>100% and >90% with the spiral detection cell in flow and stop-flow modes, respectively) was attained for CdTe QDs. Enhancement exceeding 120% was observed for QDs with emissions at 520, 575 and 603 nm (sizes of 2.8 nm, 3.3 nm and 3.6 nm) using the flow-batch detection cell in the stop-flow mode. Pronounced effect was noted for surface modifications while mercaptoethylamine was the most efficient in CL enhancement compared to mercaptopropionic acid the most commonly applied coating. Significant difference between results obtained in flow and flow-batch conditions based on the entire kinetics of the extremely fast CL reaction was discussed. The increase of the CL signal was always accompanied by reduced lifetime of the CL emission thus application of QDs in flow techniques should be always coupled with the study of the CL lifetime.

  18. Improved oxygen-activation method for determining water flow behind casing

    International Nuclear Information System (INIS)

    McKeon, D.C.; Scott, H.D.; Olesen, J.R.; Patton, G.L.; Mitchell, R.J.

    1991-01-01

    This paper reports on impulse activation which is a new oxygen-activation technique developed to detect vertical water flow and to provide a quantitative measure of water flow velocity and flow rate. Flow-loop measurements made over a wide range of water velocities are in good agreement with theoretical predictions. Measurements of up- and downward channel flow were made at the U.S. Environmental Protection Agency (EPA) leak test well in Ada, OK, to demonstrate the technique in a controlled environment and to confirm that EPA requirements have been met. A major advantage of this method over previous procedures is that a measurement is a known zero-flow zone is not required. The impulse-activation technique has improved sensitivity to both low and high flow rates. In the EPA leak test well, the technique successfully discriminated between 0- and 1.4 ft/min flow conditions. The lowest quantified velocity was 1.8 ft/min or 10 BWPD, significantly below the EPA requirement of 3 ft/min. The upper limit of detection has not been determined by exceeds 137 ft/min. The water flow log (WFL SM ) measurement uses the impulse-activation technique and a Dual-Bust SM , thermal-decay-time (TDT SM ) tool to detect water flow behind casing. An important application of this measurement is testing for fluid migration in the wellbore as part of the mechanical integrity testing process for Class I and II disposal wells. The new oxygen-activation measurement was used in numerous production wells to identify the presence of water flow behind casing. Additional applications include the identification of open fractures in horizontal wells and the quantification of water flow in the tubing/casing annulus in injection and production wells

  19. A study on nozzle flow and spray characteristics of piezo injector for next generation high response injection

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Wook [Korea Institue of Machinery and Materials, Daejeon (Korea, Republic of); Min, Kyoung Doug [Seoul National University, Seoul (Korea, Republic of)

    2006-06-15

    Most diesel injector, which is currently used in high-pressure common rail fuel injection system of diesel engine, is driven by the solenoid coil energy for its needle movement. The main disadvantage of this solenoid-driven injector is a high power consumption, high power loss through solenoid coil and relatively fixed needle response's problem. In this study, a prototype piezo-driven injector, as a new injector mechanism driven by piezoelectric energy based on the concept of inverse piezo-electric effect, has been designed and fabricated to know the effect of piezo-driven injection processes on the diesel spray structure and internal nozzle flow. Firstly we investigated the spray characteristics in a constant volume chamber pressurized by nitrogen gas using the back diffusion light illumination method for high-speed temporal photography and also analyzed the inside nozzle flow by a fully transient simulation with cavitation model using VOF(Volume Of Fraction) method. The numerical calculation has been performed to simulate the cavitating flow of 3-dimensional real size single hole nozzle along the injection duration. Results were compared between a conventional solenoid-driven injector and piezo-driven injector, both equipped with the same micro-sac multi-hole injection nozzle. The experimental results show that the piezo-driven injector has short injection delay and a faster spray development and produces higher injection velocity than the solenoid-driven injector. And the predicted simulation results with the degree of cavitation's generation inside nozzle for faster needle response in a piezo-driven injector were reflected to spray development in agreement with the experimental spray images.

  20. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry in water samples

    Directory of Open Access Journals (Sweden)

    Arpa Şahin Ç.

    2013-04-01

    Full Text Available A simple, rapid and inexpensive solidified floating organic drop microextraction (SFODME and flow injection flame atomic absorption spectrometric determination (FI-FAAS method for copper was developed. 3-amino-7-dimethylamino-2-methylphenazine (Neutral red, NR was used as the complexing agent. Several factors affecting the microextraction efficiency, such as, pH, NR and sodium dodecylbenzenesulfonate (SDBS concentration, extraction time, stirring rate, and temperature were investigated and optimized. Under optimized experimental conditions an enrichment factor of 541 was obtained for 100 mL of sample solution. The calibration graph was linear in the range of 0.5 – 20.0 ng mL–1 and the limit of detection (3s was 0.18 ng mL–1, the limit of quantification (10s was 0.58 ng mL–1. The relative standard deviation (RSD for 10 replicate measurements of 10 ng mL–1 copper was 2.7%. The developed method was successfully applied to the extraction and determination of copper in different certified reference materials (Estuarine water, Slew 3 and fortified water, TM 23.2 and real water samples and satisfactory results were obtained.

  1. Rheological and thermal analysis of the filling stage of injection moulding

    Directory of Open Access Journals (Sweden)

    A. Szucs

    2012-08-01

    Full Text Available Flow conditions are different in the cavity of the injection mould from the capillary flow of a laboratory rheological instrument. An injection moulding slit die rheometer (Rheo-mould was designed with a series of slit and orifice dies. Four pressure sensors were built in the stationary side of the mould, therefore the pressure could be measured at four different places. A changeable slit die insert was designed in the moving side. The shear stress and the shear rate can be calculated from the pressure gradient and from the flow rate of the melt, respectively. Flow curves of low density polyethylene were determined using Bagley, Rabinowitsch and Mooney corrections. The results were compared to the flow curves determined by Göttfert and Haake capillary equipments. It was found that the agreement between the methods is excellent.

  2. Start-up assist by magnetized plasma flow injection in TPE-RX reversed-field pinch

    Energy Technology Data Exchange (ETDEWEB)

    Asai, T. [College of Science and Technology, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan)]. E-mail: asai@phys.cst.nihon-u.ac.jp; Nagata, M. [Graduate School of Engineering, University of Hyogo, Himeji (Japan); Koguchi, H. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Hirano, Y. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Sakakita, H. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Yambe, K. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Kiyama, S. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)

    2006-11-15

    A reversed-field pinch (RFP) start-up assisted by a magnetized plasma flow injection was demonstrated for the first time on a TPE-RX machine. This sequence of experiments aimed to establish a new method of ionization, gas-fill and helicity injection in the start-up phase of an RFP. In this start-up method, magnetized and well-ionized plasma is formed by a magnetized coaxial plasma gun and injected into the torus chamber as an initial pre-ionized plasma for RFP formation. In the initial experiments, attenuated density pump-out and comparatively slow decay of the toroidal flux and plasma current were observed as evidence of its being an effective start-up method.

  3. Flow Injection Potentiometric Determination of Cd2+ Ions Using a Coated Graphite Plasticized PVC-Membrane Electrode Based on 1, 3-Bis(2-cyanobenzene)triazene.

    Science.gov (United States)

    Shamsipur, Mojtaba; Sahari, Shokat; Payehghadr, Mahmood; Alizadeh, Kamal

    2011-09-01

    1, 3-Bis(2-cyanobenzene)triazene, L, was used as a suitable ionophore for the fabrication of a new PVC-based polymeric membrane coated graphite electrode for selective sensing of Cd2+ ion. The electrode exhibited a selective linear Nernstian response to Cd2+ ion at an optimal pH range of 6-9 with a limit of detection of 8.0 × 10-6 M and a fast response time of about 2 s. The electrode was used as a proper detection system in flow-injection potentiometry of cadmium ion and resulted in well defined peaks for cadmium ions with stable baseline, excellent reproducibility and high sampling rates of over 100 injections per hour. It showed good stability, reproducibility and fast response time. The practical utility of the proposed system has also been reported.

  4. Simultaneous determination of 2 aconitum alkaloids and 12 ginsenosides in Shenfu injection by ultraperformance liquid chromatography coupled with a photodiode array detector with few markers to determine multicomponents

    Directory of Open Access Journals (Sweden)

    Ai-Hua Ge

    2015-06-01

    Full Text Available A method with few markers to determine multicomponents was established and validated to evaluate the quality of Shenfu injection by ultraperformance liquid chromatography coupled with a photodiode array detector. The separations were performed on an ACQUITY UPLC BEH C18 (2.1 × 50 mm2, 1.7 μm column. Methanol and 0.1% formic acid aqueous solution were used as the mobile phase. The flow rate was 0.3 mL/min. 2 aconitum alkaloids and 12 ginsenosides could be perfectly separated within 15 minutes. Ginsenoside Rg1 and benzoylmesaconine, the easily available active components, were employed as the maker components to calculate the relative correction factors of other components in Shenfu injection, Panax ginseng and Aconitum carmichaeli. The external standard method was also established to validate the feasibility of the method with few markers to determine multicomponents. Parameter p and the principal component analysis method were employed to investigate the disparities among batches for the effective quality control of Shenfu injection. The results demonstrated that the ultraperformance liquid chromatography coupled with a photodiode array detector method with few markers to determine multicomponents could be used as a powerful tool for the quality evaluation of traditional Chinese medicines and their preparations.

  5. Review of recent applications of flow injection spectrophotometry to pharmaceutical analysis

    International Nuclear Information System (INIS)

    Tzanavaras, Paraskevas D.; Themelis, Demetrius G.

    2007-01-01

    Pharmaceutical analysis is one of the most important fields in analytical chemistry. The discovery of new drugs and the on-going update of international regulations for the safety and efficacy of pharmaceutical formulations demand the continuous development of new analytical methods. Inevitably, automation plays an important role, especially when a lot of samples have to be analyzed in the minimum of time. The present study reviews the applications of flow injection (FI) spectrophotometry to the determination of active pharmaceutical ingredients (APIs) in their respective formulations. However, the topic covered in this study is important not only to pharmaceutical analytical scientists. The principles, figures of merit and 'chemistry' of the presented methods can be of interest to bio-analytical and clinical chemists as well for the analysis of biological samples, to environmental analysts that study the up-to-date demand of the determination of the fate of pharmaceuticals in the environment and even to toxicologists and forensic scientists. This review covers scientific contributions published later than 2000. A variety of FI procedures based on homogeneous (direct UV measurements, colour-forming reactions, metal-drug interactions) and heterogeneous (optical sensors and solid-phase reactors) systems are discussed. A third section covers on-line sample pretreatment (solid-phase extraction, liquid-liquid extraction, on-line digestion, etc.)

  6. Intelligent methods for the process parameter determination of plastic injection molding

    Science.gov (United States)

    Gao, Huang; Zhang, Yun; Zhou, Xundao; Li, Dequn

    2018-03-01

    Injection molding is one of the most widely used material processing methods in producing plastic products with complex geometries and high precision. The determination of process parameters is important in obtaining qualified products and maintaining product quality. This article reviews the recent studies and developments of the intelligent methods applied in the process parameter determination of injection molding. These intelligent methods are classified into three categories: Case-based reasoning methods, expert system- based methods, and data fitting and optimization methods. A framework of process parameter determination is proposed after comprehensive discussions. Finally, the conclusions and future research topics are discussed.

  7. The Optimisation of Processing Condition for Injected Mould Polypropylene-Nanoclay-Gigantochloa Scortechinii based on Melt Flow Index

    Science.gov (United States)

    Othman, M. H.; Rosli, M. S.; Hasan, S.; Amin, A. M.; Hashim, M. Y.; Marwah, O. M. F.; Amin, S. Y. M.

    2018-03-01

    The fundamental knowledge of flow behaviour is essential in producing various plastic parts injection moulding process. Moreover, the adaptation of advanced polymer-nanocomposites such as polypropylene-nanoclay with natural fibres, for instance Gigantochloa Scortechinii may boost up the mechanical properties of the parts. Therefore, this project was proposed with the objective to optimise the processing condition of injected mould polypropylene-nanoclay-Gigantochloa Scortechini fibres based on the flow behaviour, which was melt flow index. At first, Gigantochloa Scortechinii fibres have to be preheated at temperature 120°C and then mixed with polypropylene, maleic anhydride modified polypropylene oligomers (PPgMA) and nanoclay by using Brabender Plastograph machine. Next, forms of pellets were produced from the samples by using Granulator machine for use in the injection moulding process. The design of experiments that was used in the injection moulding process was Taguchi Method Orthogonal Array -L934. Melt Flow Index (MF) was selected as the response. Based on the results, the value of MFI increased when the fiber content increase from 0% to 3%, which was 17.78 g/10min to 22.07 g/10min and decreased from 3% to 6%, which was 22.07 g/10min to 20.05 g/10min and 3%, which gives the highest value of MFI. Based on the signal to ratio analysis, the most influential parameter that affects the value of MFI was the melt temperature. The optimum parameter for 3% were 170°C melt temperature, 35% packing pressure, 30% screw speed and 3 second filling time.

  8. Assessment of effect of intravitreal ranibizumab injection on the ocular blood flow in patients with neovascular age-related macular degeneration

    Directory of Open Access Journals (Sweden)

    V. V. Neroev

    2014-07-01

    Full Text Available Purpose: To evaluate the effect of intravitreal ranibizumab injection on the ocular blood flow in patients with neovascular agerelatedmacular degeneration (AMD.Methods: 35 patients with wet AMD undergone intravitreal 0.5 mg ranibizumab injection. Color Doppler Imaging (CDI and dopplerographywere used to measure hemodynamic parameters including the peak systolic velocity (Vsyst, cm / s, end-diastolic velocity (V diast, cm / s, and resistance index (RI of blood flow in the central retinal artery (CRA, the short posterior ciliary arteries (PCA, and the ophthalmic artery (OA. All patients were examined before and after injection on day 1‑7 and 30 day during the 3‑month follow up period.Results: Before intravitreal injection Vsyst was decreased in short PCA (p<0.05, RI in CRA and in short PCA significantly increased in comparison with normal index in same vessels. The peak systolic velocity in OA, in CRA and in short PCA was not significantly changed. After second injection resistance index in CRA and in short PCA was normalized.Conclusion: There was not impairment of ocular blood flow in retinal and choroidal after monthly intravitreal injection of ranibizumab during the 3‑month follow up period.

  9. Assessment of effect of intravitreal ranibizumab injection on the ocular blood flow in patients with neovascular age-related macular degeneration

    Directory of Open Access Journals (Sweden)

    V. V. Neroev

    2013-01-01

    Full Text Available Purpose: To evaluate the effect of intravitreal ranibizumab injection on the ocular blood flow in patients with neovascular agerelatedmacular degeneration (AMD.Methods: 35 patients with wet AMD undergone intravitreal 0.5 mg ranibizumab injection. Color Doppler Imaging (CDI and dopplerographywere used to measure hemodynamic parameters including the peak systolic velocity (Vsyst, cm / s, end-diastolic velocity (V diast, cm / s, and resistance index (RI of blood flow in the central retinal artery (CRA, the short posterior ciliary arteries (PCA, and the ophthalmic artery (OA. All patients were examined before and after injection on day 1‑7 and 30 day during the 3‑month follow up period.Results: Before intravitreal injection Vsyst was decreased in short PCA (p<0.05, RI in CRA and in short PCA significantly increased in comparison with normal index in same vessels. The peak systolic velocity in OA, in CRA and in short PCA was not significantly changed. After second injection resistance index in CRA and in short PCA was normalized.Conclusion: There was not impairment of ocular blood flow in retinal and choroidal after monthly intravitreal injection of ranibizumab during the 3‑month follow up period.

  10. Water injection profiling

    International Nuclear Information System (INIS)

    Arnold, D.M.

    1982-01-01

    A method of neutron-gamma logging is described, in which water, injected in a cased well borehole with peforations, is irradiated with neutrons of 10 MeV or greater, and subsequent gamma radiation is detected by a pair of detectors along the borehole. Counting rates of detectors are analyzed in terms of two gamma ray energy windows. Linear flow velocity of fluid moving downward within the casing is used in conjunction with count rate data to determine volume flow rates of water moving in other directions. Apparatus includes a sonde with a neutron source and appropriate gamma sensors

  11. Flow injection gas chromatography with sulfur chemiluminescence detection for the analysis of total sulfur in complex hydrocarbon matrixes.

    Science.gov (United States)

    Hua, Yujuan; Hawryluk, Myron; Gras, Ronda; Shearer, Randall; Luong, Jim

    2018-01-01

    A fast and reliable analytical technique for the determination of total sulfur levels in complex hydrocarbon matrices is introduced. The method employed flow injection technique using a gas chromatograph as a sample introduction device and a gas phase dual-plasma sulfur chemiluminescence detector for sulfur quantification. Using the technique described, total sulfur measurement in challenging hydrocarbon matrices can be achieved in less than 10 s with sample-to-sample time ideal for fast analysis or trace sulfur analysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Modelling and Simulation of Structural Deformation of Isothermal Subsurface Flow and Carbon Dioxide Injection

    KAUST Repository

    El-Amin, Mohamed; Negara, Ardiansyah; Salama, Amgad; Sun, Shuyu

    2011-01-01

    force term. The flux continuity condition is used at interfaces between different permeability layers of the heterogeneous medium. We analyze the vertical migration of a CO2 plume injected into a 2D layered reservoir. Analysis of distribution of flow

  13. Artificial neural networks study of the catalytic reduction of resazurin: stopped-flow injection kinetic-spectrophotometric determination of Cu(II) and Ni(II)

    International Nuclear Information System (INIS)

    Magni, Diana M.; Olivieri, Alejandro C.; Bonivardi, Adrian L.

    2005-01-01

    An artificial neural network (ANN) procedure was used in the development of a catalytic spectrophotometric method for the determination of Cu(II) and Ni(II) employing a stopped-flow injection system. The method is based on the catalytic action of these ions on the reduction of resazurin by sulfide. ANNs trained by back-propagation of errors allowed us to model the systems in a concentration range of 0.5-6 and 1-15 mg l -1 for Cu(II) and Ni(II), respectively, with a low relative error of prediction (REP) for each cation: REP Cu(II) = 0.85% and REP Ni(II) = 0.79%. The standard deviations of the repeatability (s r ) and of the within-laboratory reproducibility (s w ) were measured using standard solutions of Cu(II) and Ni(II) equal to 2.75 and 3.5 mg l -1 , respectively: s r [Cu(II)] = 0.039 mg l -1 , s r [Ni(II)] = 0.044 mg l -1 , s w [Ni(II)] = 0.045 mg l -1 and s w [Ni(II)] = 0.050 mg l -1 . The ANNs-kinetic method has been applied to the determination of Cu(II) and Ni(II) in electroplating solutions and provided satisfactory results as compared with flame atomic absorption spectrophotometry method. The effect of resazurin, NaOH and Na 2 S concentrations and the reaction temperature on the analytical sensitivity is discussed

  14. Analytical study of electron flows with a virtual cathode

    International Nuclear Information System (INIS)

    Dubinov, A.E.

    2000-01-01

    The dynamics of the electron flow behavior by its injection into a half-space is considered. Two problems are considered, namely the long-term injection of a monoenergetic electron flow and instantaneous flow injection with an assigned electron energy spectrum. The all flow electrons in both cases return to the injection plane. The simple analytical self-consistent model of the initial stage of the virtual cathode formation in a plane-parallel equipotential gap is plotted in the course of analysis whereof the duration of the virtual cathode formation process is determined. The performance of this model is not limited by the multivalence of the electron velocity in the flow. This makes it possible to extend the frames of the model performance relative to the moment of the virtual cathode formation and to consider its dynamics. The frequency of electron oscillations in the potential cathode-virtual cathode well is determined on the basis of the above model [ru

  15. Flow Injection Photochemical Vapor Generation Coupled with Miniaturized Solution-Cathode Glow Discharge Atomic Emission Spectrometry for Determination and Speciation Analysis of Mercury.

    Science.gov (United States)

    Mo, Jiamei; Li, Qing; Guo, Xiaohong; Zhang, Guoxia; Wang, Zheng

    2017-10-03

    A novel, compact, and green method was developed for the determination and speciation analysis of mercury, based on flow injection photochemical vapor generation (PVG) coupled with miniaturized solution cathode glow discharge-atomic emission spectroscopy (SCGD-AES). The SCGD was generated between a miniature hollow titanium tube and a solution emerging from a glass capillary. Cold mercury vapor (Hg(0)) was generated by PVG and subsequently delivered to the SCGD for excitation, and finally the emission signals were recorded by a miniaturized spectrograph. The detection limits (DLs) of Hg(II) and methylmercury (MeHg) were both determined to be 0.2 μg L -1 . Moreover, mercury speciation analysis could also be performed by using different wavelengths and powers from the UV lamp and irradiation times. Both Hg(II) and MeHg can be converted to Hg(0) for the determination of total mercury (T-Hg) with 8 W/254 nm UV lamp and 60 s irradiation time; while only Hg(II) can be reduced to Hg(0) and determined selectively with 4 W/365 nm UV lamp and 20 s irradiation time. Then, the concentration of MeHg can be calculated by subtracting the Hg(II) from the T-Hg. Because of its similar sensitivity and DL at 8 W/254 nm, the simpler and less toxic Hg(II) was used successfully as a primary standard for the quantification of T-Hg. The novel PVG-SCGD-AES system provides not only a 365-fold improvement in the DL for Hg(II) but also a nonchromatographic method for the speciation analysis of mercury. After validating its accuracy, this method was successfully used for mercury speciation analysis of water and biological samples.

  16. Advancement of In-Flight Alumina Powder Spheroidization Process with Water Droplet Injection Using a Small Power DC-RF Hybrid Plasma Flow System

    Science.gov (United States)

    Jang, Juyong; Takana, Hidemasa; Park, Sangkyu; Nishiyama, Hideya

    2012-09-01

    The correlation between plasma thermofluid characteristics and alumina powder spheroidization processes with water droplet injection using a small power DC-RF hybrid plasma flow system was experimentally clarified. Micro-sized water droplets with a low water flow rate were injected into the tail of thermal plasma flow so as not to disturb the plasma flow directly. Injected water droplets were vaporized in the thermal plasma flow and were transported upstream in the plasma flow to the torch by the backflow. After dissociation of water, the production of hydrogen was detected by the optical emission spectroscopy in the downstream RF plasma flow. The emission area of the DC plasma jet expanded and elongated in the vicinity of the RF coils. Additionally, the emission area of RF plasma flow enlarged and was visible as red emission in the downstream RF plasma flow in the vicinity below the RF coils due to hydrogen production. Therefore, the plasma flow mixed with produced hydrogen increased the plasma enthalpy and the highest spheroidization rate of 97% was obtained at a water flow rate of 15 Sm l/min and an atomizing gas flow rate of 8 S l/min using a small power DC-RF hybrid plasma flow system.

  17. Modelling and Simulation of Structural Deformation of Isothermal Subsurface Flow and Carbon Dioxide Injection

    KAUST Repository

    El-Amin, Mohamed

    2011-05-15

    Injection of CO2 in hydrocarbon reservoir has double benefit. On the one hand, it is a profitable method due to issues related to global warming, and on the other hand it is an effective mechanism to enhance hydrocarbon recovery. Such injection associates complex processes involving, e.g., solute transport of dissolved materials, in addition to local changes in density of the phases. Also, increasing carbon dioxide injection may cause a structural deformation of the medium, so it is important to include such effect into the model. The structural deformation modelling in carbon sequestration is important to evaluate the medium stability to avoid CO2 leakage to the atmosphere. On the other hand, geologic formation of the medium is usually heterogeneous and consists of several layers of different permeability. In this work we conduct numerical simulation of two-phase flow in a heterogeneous porous medium domain with dissolved solute transport as well as structural deformation effects. The solute transport of the dissolved component is described by concentration equation. The structural deformation for geomechanics is derived from a general local differential balance equation with neglecting the local mass balance of solid phase and the inertial force term. The flux continuity condition is used at interfaces between different permeability layers of the heterogeneous medium. We analyze the vertical migration of a CO2 plume injected into a 2D layered reservoir. Analysis of distribution of flow field components such as saturation, pressures, velocities, and CO2 concentration are presented.

  18. Quantitative determination of the regional cerebral blood flow with 133Xe

    International Nuclear Information System (INIS)

    Otto, H.J.; Abraham, K.; Freitag, J.; Koch, R.D.; Freitag, G.; Hoefs, R.

    1982-01-01

    After injection of 133 Xe into the A. carotis interna, the regional blood flow in the brain was determined with a 10-channel measuring unit. From the first clinical evaluation of the findings in 35 patients, the following conclusions can be drawn: 1. In epileptics, a localized hyperemia indicates very probably a latent increased convulsive activity. 2. The measurement of the cerebral blood flow does not yield a contribution to the diagnosis of the type of cerebral tumors. 3. As consequence of mass shifting of space occupying processes particularly endangered brain sections, also remote from the focus proper, show a localized pathological hyeperemia (morbid 'luxus perfusion'). 4. Of greatest importance is the method with regard to the elucidation of pathophysiological relations, as well as of questions in connection with the blood/brain barrier function, and concerning the indication for and the estimation of the results of vascular interventions. (author)

  19. Exploiting an automated microfluidic hydrodynamic sequential injection system for determination of phosphate.

    Science.gov (United States)

    Khongpet, Wanpen; Pencharee, Somkid; Puangpila, Chanida; Kradtap Hartwell, Supaporn; Lapanantnoppakhun, Somchai; Jakmunee, Jaroon

    2018-01-15

    A microfluidic hydrodynamic sequential injection (μHSI) spectrophotometric system was designed and fabricated. The system was built by laser engraving a manifold pattern on an acrylic block and sealing with another flat acrylic plate to form a microfluidic channel platform. The platform was incorporated with small solenoid valves to obtain a portable setup for programmable control of the liquid flow into the channel according to the HSI principle. The system was demonstrated for the determination of phosphate using a molybdenum blue method. An ascorbic acid, standard or sample, and acidic molybdate solutions were sequentially aspirated to fill the channel forming a stack zone before flowing to the detector. Under the optimum condition, a linear calibration graph in the range of 0.1-6mg P L -1 was obtained. The detection limit was 0.1mgL -1 . The system is compact (5.0mm thick, 80mm wide × 140mm long), durable, portable, cost-effective, and consumes little amount of chemicals (83μL each of molybdate and ascorbic acid, 133μL of the sample solution and 1.7mL of water carrier/run). It was applied for the determination of phosphate content in extracted soil samples. The percent recoveries of the analysis were obtained in the range of 91.2-107.3. The results obtained agreed well with those of the batch spectrophotometric method. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Analysis of transient flows in gasoline direct injection systems: effects on unsteady air entrainment by the spray; Analyse des ecoulements transitoires dans les systemes d'injection directe essence: effets sur l'entrainement d'air instationnaire du spray

    Energy Technology Data Exchange (ETDEWEB)

    Delay, G

    2005-03-15

    The aim of this study is to determine instantaneous liquid flow rate oscillations effect on non stationary air entrainment of an injector conical spray (Gasoline Direct Injection). The tools we use are either experimental or numerical ones. An instantaneous flow rate determination method is used. It is based on pulsated flows physics and only requires the velocity at the centerline of a pipe mounted just before the injector. So, it is possible to 'rebuild' the instantaneous velocity distributions and then to get the instantaneous liquid flow rate (Laser Doppler Anemometry measurements). A mechanical and hydraulics modeling software (AMESim) is necessary to get injector outlet flow rate. Simulations are validated by both 'rebuilding' method results and common rail pressure measurements. Fluorescent Particle Image Velocimetry (FPIV), suited to dense two -phase flows, is used to measure air flow around and inside the conical spray. Velocity measurements close to the spray frontier are used to compute instantaneous air entrainment. Considering droplets momentum exchange with air and thanks to droplets diameters and liquid velocities measurements at the nozzle exit, a transient air entrainment model is proposed according to FPIV measurements. (author)

  1. Investigation of iron(III) reduction and trace metal interferences in the determination of dissolved iron in seawater using flow injection with luminol chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Ussher, Simon J. [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Milne, Angela [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320 (United States); Landing, William M. [Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320 (United States); Attiq-ur-Rehman, Kakar [Department of Chemistry, University of Balochistan, Quetta (Pakistan); Seguret, Marie J.M.; Holland, Toby [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Achterberg, Eric P. [National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH (United Kingdom); Nabi, Abdul [Department of Chemistry, University of Balochistan, Quetta (Pakistan); Worsfold, Paul J., E-mail: pworsfold@plymouth.ac.uk [School of Earth, Ocean and Environmental Sciences (SEOES), University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2009-10-12

    A detailed investigation into the performance of two flow injection-chemiluminescence (FI-CL) manifolds (with and without a preconcentration column) for the determination of sub-nanomolar dissolved iron (Fe(II) + Fe(III)), following the reduction of Fe(III) by sulphite, in seawater is described. Kinetic experiments were conducted to examine the efficiency of reduction of inorganic Fe(III) with sulphite under different conditions and a rigorous study of the potential interference caused by other transition metals present in seawater was conducted. Using 100 {mu}M concentrations of sulphite a reduction time of 4 h was sufficient to quantitatively reduce Fe(III) in seawater. Under optimal conditions, cobalt(II) and vanadium(IV)/(III) were the major positive interferences and strategies for their removal are reported. Specifically, cobalt(II) was masked by the addition of dimethylglyoxime to the luminol solution and vanadium(IV) was removed by passing the sample through an 8-hydroxyquinoline column in a low pH carrier stream. Manganese(II) also interfered by suppression of the CL response but this was not significant at typical open ocean concentrations.

  2. Three-dimensional analysis of internal flow characteristics in the injection nozzle tip of direct-injection diesel engines; Sanjigen suchi kaiseki ni yoru DI diesel kikan no nenryo funsha nozzle nai ryudo tokusei no kaimei

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, H; Matsui, Y; Kimura, S [Nissan Motor Co. Ltd. Tokyo (Japan)

    1997-10-01

    To reduce the exhaust emissions and fuel consumption of direct-injection diesel engines, it is essential to optimize the fuel injection equipment closely related to combustion and emission characteristics. In this study, three-dimensional computation has been applied to investigate the effects of the injection nozzle specifications (e.g., sac volume, round shape at the inlet of the nozzle hole) and needle tip deviation on internal flow characteristics. The computational results revealed that the effects of the nozzle specifications and needle tip deviation with a smaller needle lift on internal flow characteristics and a general approach to optimize the injection nozzle specifications were obtained. 3 refs., 10 figs., 1 tab.

  3. Cold water injection nozzles

    International Nuclear Information System (INIS)

    Kura, Masaaki; Maeda, Masamitsu; Endo, Takio.

    1979-01-01

    Purpose: To inject cold water in a reactor without applying heat cycles to a reactor container and to the inner wall of a feedwater nozzle by securing a perforated plate at the outlet of the cold water injection nozzle. Constitution: A disc-like cap is secured to the final end of a return nozzle of a control rod drive. The cap prevents the flow of a high temperature water flowing downward in the reactor from entering into the nozzle. The cap is perforated with a plurality of bore holes for injecting cold water into the reactor. The cap is made to about 100 mm in thickness so that the cold water passing through the bore holes is heated by the heat conduction in the cap. Accordingly, the flow of high temperature water flowing downwardly in the reactor is inhibited by the cap from backward flowing into the nozzle. Moreover, the flow of the cold water in the nozzle is controlled and rectified when passed through the bore holes in the cap and then injected into the reactor. (Yoshino, Y.)

  4. How Flow Injection Analysis (FIA) over the past 25 years has changed our way of performing chemical analyses

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Miró, Manuel

    2007-01-01

    Briefly looking back on the impact of flow injection analysis (FIA), as reflected in the rapid growth of publications in the scientific literature, and touching upon many of the novel and unique analytical chemical possibilities that FIA and its sequels, sequential injection analysis (SIA) and La...

  5. Second-order Data by Flow Injection Analysis with Spectrophotometric Diode-array Detection and Incorporated Gel-filtration Chromatographic Column

    DEFF Research Database (Denmark)

    Bechmann, Iben Ellegaard

    1997-01-01

    A flow injection analysis (FIA) system furnished with a gel-filtration chromatographic column and with photodiode-array detection was used for the generation of second-order data. The system presented is a model system in which the analytes are blue dextran, potassium hexacyanoferrate(III) and he......A flow injection analysis (FIA) system furnished with a gel-filtration chromatographic column and with photodiode-array detection was used for the generation of second-order data. The system presented is a model system in which the analytes are blue dextran, potassium hexacyanoferrate...

  6. Determination of thiomersal by flow injection coupled with microwave-assisted photochemical online oxidative decomposition of organic mercury and cold vapor atomic fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Campanella, Beatrice; Onor, Massimo; Mascherpa, Marco Carlo; D’Ulivo, Alessandro [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Ferrari, Carlo [National Research Council of Italy, C.N.R., Istituto Nazionale di Ottica, INO–UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Bramanti, Emilia, E-mail: bramanti@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2013-12-04

    Graphical abstract: -- Highlights: •Thiomersal was determined on line using FI-MW/UV-CVGAFS. •MW/UV allows a “green” on line oxidation of organic mercury to Hg{sup II}. •Each measure requires less than 5 min with a LOD of 3 ng mL{sup −1} (as mercury). •Hg concentration in commercial ophthalmic solutions ranges between 7.5 and 59.0 μg mL{sup −1}. -- Abstract: We developed a flow injection (FI) method for the determination of thiomersal (sodium ethylmercurithiosalicylate, C{sub 9}H{sub 9}HgNaO{sub 2}S) based on the UV/microwave (MW) photochemical, online oxidation of organic mercury, followed by cold vapor generation atomic fluorescence spectrometry (CVG-AFS) detection. Thiomersal was quantitatively converted in the MW/UV process to Hg(II), with a yield of 97 ± 3%. This reaction was followed by the reduction of Hg(II) to Hg(0) performed in a knotted reaction coil with NaBH{sub 4} solution, and AFS detection in an Ar/H{sub 2} miniaturized flame. The method was linear in the 0.01–2 μg mL{sup −1} range, with a LOD of 0.003 μg mL{sup −1}. This method has been applied to the determination of thiomersal in ophthalmic solutions, with recoveries ranging between 97% and 101%. We found a mercury concentration in commercial ophthalmic solutions ranging between 7.5 and 59.0 μg mL{sup −1}.

  7. A review of flow analysis methods for determination of radionuclides in nuclear wastes and nuclear reactor coolants.

    Science.gov (United States)

    Trojanowicz, Marek; Kołacińska, Kamila; Grate, Jay W

    2018-06-01

    The safety and security of nuclear power plant operations depend on the application of the most appropriate techniques and methods of chemical analysis, where modern flow analysis methods prevail. Nevertheless, the current status of the development of these methods is more limited than it might be expected based on their genuine advantages. The main aim of this paper is to review the automated flow analysis procedures developed with various detection methods for the nuclear energy industry. The flow analysis methods for the determination of radionuclides, that have been reported to date, are primarily focused on their environmental applications. The benefits of the application of flow methods in both monitoring of the nuclear wastes and process analysis of the primary circuit coolants of light water nuclear reactors will also be discussed. The application of either continuous flow methods (CFA) or injection methods (FIA, SIA) of the flow analysis with the β-radiometric detection shortens the analysis time and improves the precision of determination due to mechanization of certain time-consuming operations of the sample processing. Compared to the radiometric detection, the mass spectrometry (MS) detection enables one to perform multicomponent analyses as well as the determination of transuranic isotopes with much better limits of detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Simulation of Spray Injection in the Pressurizer Using RELAP5

    Directory of Open Access Journals (Sweden)

    S. Dibyo

    2017-08-01

    Full Text Available A modeling research using Relap5 to assess the pressurizer of a pressurized water reactor(PWR power plant has been performed. The heater and water injection systems in the pressurizer system of the PWRare of greatimportance for system pressure control.The heater is designed to increase the pressure while the water sprayer injection is to perform depressurization. Most of studies conducted in the past mainly focused on determining the effects of nozzle spray design and droplet size using testing loops. The purpose of this simulation is to analyze the spray injection flow rate against the pressure characteristics of the pressurizer using RELAP5. Through this approach, the optimum injection flow rate of full scale plant pressurizer can be analyzed. The parameters investigated are pressure and temperature.In RELAP5, the pressurizer tank wasmodeled with six volume nodes and the heater was modeled by using heat structure. In the model, the sprayer takes water from the cold leg to inject it into the top of tank region.The resultsshowedthat the mass flow of about 4 kg/s is the mosteffectivevalueto limit pressure in the pressurizer to below 15.7 MPa. However, the flow rates of 8 kg/s and more cause overpressure. This simulation is usefulto complement the data related to the water flow rate injection systems of the pressurizer. Normal 0 false false false EN-US X-NONE X-NONE Flow analysis techniques for phosphorus: an overview.

    Science.gov (United States)

    Estela, José Manuel; Cerdà, Víctor

    2005-04-15

    A bibliographical review on the implementation and the results obtained in the use of different flow analytical techniques for the determination of phosphorus is carried out. The sources, occurrence and importance of phosphorus together with several aspects regarding the analysis and terminology used in the determination of this element are briefly described. A classification as well as a brief description of the basis, advantages and disadvantages of the different existing flow techniques, namely; segmented flow analysis (SFA), flow injection analysis (FIA), sequential injection analysis (SIA), all injection analysis (AIA), batch injection analysis (BIA), multicommutated FIA (MCFIA), multisyringe FIA (MSFIA) and multipumped FIA (MPFIA) is also carried out. The most relevant manuscripts regarding the analysis of phosphorus by means of flow techniques are herein classified according to the detection instrumental technique used with the aim to facilitate their study and obtain an overall scope. Finally, the analytical characteristics of numerous flow-methods reported in the literature are provided in the form of a table and their applicability to samples with different matrixes, namely water samples (marine, river, estuarine, waste, industrial, drinking, etc.), soils leachates, plant leaves, toothpaste, detergents, foodstuffs (wine, orange juice, milk), biological samples, sugars, fertilizer, hydroponic solutions, soils extracts and cyanobacterial biofilms are tabulated.

  9. Fast cholesterol detection using flow injection microfluidic device with functionalized carbon nanotubes based electrochemical sensor.

    Science.gov (United States)

    Wisitsoraat, A; Sritongkham, P; Karuwan, C; Phokharatkul, D; Maturos, T; Tuantranont, A

    2010-12-15

    This work reports a new cholesterol detection scheme using functionalized carbon nanotube (CNT) electrode in a polydimethylsiloxane/glass based flow injection microfluidic chip. CNTs working, silver reference and platinum counter electrode layers were fabricated on the chip by sputtering and low temperature chemical vapor deposition methods. Cholesterol oxidase prepared in polyvinyl alcohol solution was immobilized on CNTs by in-channel flow technique. Cholesterol analysis based on flow injection chronoamperometric measurement was performed in 150-μm-wide and 150-μm-deep microchannels. Fast and sensitive real-time detection was achieved with high throughput of more than 60 samples per hour and small sample volume of 15 μl. The cholesterol sensor had a linear detection range between 50 and 400 mg/dl. In addition, low cross-sensitivities toward glucose, ascorbic acid, acetaminophen and uric acid were confirmed. The proposed system is promising for clinical diagnostics of cholesterol with high speed real-time detection capability, very low sample consumption, high sensitivity, low interference and good stability. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Espectrofotometria de zinco em fertilizantes em fluxo Flow injection spectrophotometry of zinc in mineral fertilizers

    Directory of Open Access Journals (Sweden)

    Arnaldo Antonio Rodella

    1999-07-01

    Full Text Available Um sistema de análise química por injeção em fluxo é proposto para a determinação espectrofotométrica de zinco em amostras de misturas de fertilizantes minerais, empregando-se zincon como reagente cromogênico. O procedimento analítico envolve redução de íons metálicos por ácido ascórbico, complexação com íon cianeto, seguindo-se a descomplexação seletiva do zinco com formaldeído, liberando-o para que reaja com o zincon formando um complexo azul. A aplicação do método proposto à extratos de mistura de fertilizantes indicou que a ação de interferentes pode ser contornada e que resultados comparáveis aos da espectrometria de absorção atômica são obtidos.A flow injection system for zinc analysis in mineral fertilizer mixtures is proposed using zincon as chromogenic reagent. The effect of interfering ions such as Cu2+, Fe3+, Mn2+ was eliminated by reduction (using ascorbic acid and complexation of these metal íons with cyanide, with zinc included. Zinc is allowed to react with zincon only after the destruction of the zinc cyano complex with formaldehyde. Flow injection analysis permitted efficient control of the reaction time so that only the zinc ion is set free to produce a blue complex with zincon. Zinc was determined in 16 fertilizer mixtures (3 replicates with precision and accuracy comparable to atomic absorption spectrometry.

  11. Optimal Power Flow Control by Rotary Power Flow Controller

    Directory of Open Access Journals (Sweden)

    KAZEMI, A.

    2011-05-01

    Full Text Available This paper presents a new power flow model for rotary power flow controller (RPFC. RPFC injects a series voltage into the transmission line and provides series compensation and phase shifting simultaneously. Therefore, it is able to control the transmission line impedance and the active power flow through it. An RPFC is composed mainly of two rotary phase shifting transformers (RPST and two conventional (series and shunt transformers. Structurally, an RPST consists of two windings (stator and rotor windings. The rotor windings of the two RPSTs are connected in parallel and their stator windings are in series. The injected voltage is proportional to the vector sum of the stator voltages and so its amplitude and angle are affected by the rotor position of the two RPSTs. This paper, describes the steady state operation and single-phase equivalent circuit of the RPFC. Also in this paper, a new power flow model, based on power injection model of flexible ac transmission system (FACTS controllers, suitable for the power flow analysis is introduced. Proposed model is used to solve optimal power flow (OPF problem in IEEE standard test systems incorporating RPFC and the optimal settings and location of the RPFC is determined.

  12. Flow injection on-line dilution for zinc determination in human saliva with electrothermal atomic absorption spectrometry detection

    Energy Technology Data Exchange (ETDEWEB)

    Burguera-Pascu, Margarita [Department of Oral Medicine, School of Dentistry, University of Granada, Granada (Spain)], E-mail: margaburpas@hotmail.com; Rodriguez-Archilla, Alberto [Department of Oral Medicine, School of Dentistry, University of Granada, Granada (Spain); Burguera, Jose Luis; Burguera, Marcela; Rondon, Carlos; Carrero, Pablo [Department of Chemistry, Faculty of Sciences, University of Los Andes, Merida (Venezuela)

    2007-09-26

    An automated method is described for the determination of zinc in human saliva by electrothermal atomic absorption spectrometry (ET AAS) after on-line dilution of samples with a significant reduction of sample consumption per analysis (<0.4 mL including the dead volume of the system). In order to fulfill this aim without changing the sample transport conduits during the experiments, a flow injection (FI) dilution system was constructed. Its principal parts are: one propulsion device (peristaltic pump, PP) for either samples, standards or washing solution all located in an autosampler tray and for the surfactant solution (Triton X-100) used as diluent, and a two-position time based solenoid injector (TBSI{sub 1}) which allowed the introduction of 10 {mu}L of either solution in the diluent stream. To avoid unnecessary waste of samples, the TBSI{sub 1} also permitted the recirculation of the solutions to their respective autosampler cups. The downstream diluted solution fills a home made sampling arm assembly. The sequential deposition of 20 {mu}L aliquots of samples or standards on the graphite tube platform was carried out by air displacement with a similar time based solenoid injector (TBSI{sub 2}). The dilution procedure and the injection of solutions into the atomizer are computer controlled and synchronized with the operation of the temperature program. Samples or standards solutions were submitted to two drying steps (at 90 and 130 deg. C), followed by pyrolysis and atomization at 700 and 1700 deg. C, respectively. The aqueous calibration was linear up to 120.0 {mu}g L{sup -1} for diluted standard solutions/samples and its slope was similar (p > 0.05) to the standard addition curve, indicating lack of matrix effect. The precision tested by repeated analysis of real saliva samples was less than 3% and the detection limit (3{sigma}) was of 0.35 {mu}g L{sup -1}. To test the accuracy of the proposed procedure, recovery tests were performed, obtaining mean recovery

  13. Filterless preconcentration, flow injection analysis and detection by inductively-coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    The influence of interferences in the analysis of elements by inductively-coupled-plasma mass-spectrometry (ICP-MS) may be significantly diminished by utilising a protocol of flow-injection analysis (FIA). The method is based on filterless preconcentration of metallic elements at the walls...... of a knotted reactor that was made of nylon tubings. In the load mode, the preconcentration was accomplished by precipitation of metallic species in alkaline-buffered carriers onto the inner walls of the hydrofilic tube. After a preconcen-tration period of 40-120 seconds using sample volumes of 4-10 m...... of 10-30 were obtained in the analysis of aluminium, of chromium and of iron, which resulted in detection limits (3) down to 20 g/L at a sampling frequency of 50 per hour. The preconcentration protocol improves the selectivity thus allowing direct determination of the elements in saline media. Anionic...

  14. Cumulative Distributions and Flow Structure of Two-Passage Shear Coaxial Injector with Various Gas Injection Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Inchul; Kim, Dohun; Koo, Jaye [Korea Aerospace Univ., Goyang (Korea, Republic of)

    2013-07-15

    To verify the effect of inner- and outer-stage gas jets, a shear coaxial injector was designed to analyze the axial velocity profile and breakup phenomenon with an increase in the measurement distance. When the measurement position was increased to Z/d=100, the axial flow showed a fully developed shape due to the momentum transfer, aerodynamic drag effect, and viscous mixing. An inner gas injection, which induces a higher momentum flux ratio near the nozzle, produces the greater shear force on atomization than an outer gas injection. Inner- and Outer-stage gas injection do not affect the mixing between the inner and outer gas flow below Z/d=5. The experiment results showed that the main effect of liquid jet breakup was governed by the gas jet of an inner stage. As the nozzle exit of the outer-stage was located far from the liquid column, shear force and turbulence breaking up of the liquid jets do not fully affect the liquid column. In the case of an inner-stage gas injection momentum flux ratio within 0.84, with the increase in the outer gas momentum flux ratio, the Smd decreases. However, at an inner-stage gas jet momentum flux ratio over 1.38, the Smd shows the similar distribution.

  15. Effects of Injection Timing on Fluid Flow Characteristics of Partially Premixed Combustion Based on High-Speed Particle Image Velocimetry

    KAUST Repository

    Izadi Najafabadi, Mohammad

    2017-03-28

    Partially Premixed Combustion (PPC) is a promising combustion concept ,based on judicious tuning of the charge stratification, to meet the increasing demands of emission legislation and to improve fuel efficiency. Longer ignition delays of PPC in comparison with conventional diesel combustion provide better fuel/air mixture which decreases soot and NO emissions. Moreover, a proper injection timing and strategy for PPC can improve the combustion stability as a result of a higher level of fuel stratification in comparison with the Homogeneous Charge Compression Ignition (HCCI) concept. Injection timing is the major parameter with which to affect the level of fuel and combustion stratification and to control the combustion phasing and the heat release behavior. The scope of the present study is to investigate the fluid flow characteristics of PPC at different injection timings. To this end, high-speed Particle Image Velocimetry (PIV) is implemented in a light-duty optical engine to measure fluid flow characteristics, including the flow fields, mean velocity and cycle-resolved turbulence, inside the piston bowl as well as the squish region with a temporal resolution of 1 crank angle degree at 800 rpm. Two injectors, having 5 and 7 holes, were compared to see their effects on fluid flow and heat release behavior for different injection timings. Reactive and non-reactive measurements were performed to distinguish injection-driven and combustion-driven turbulence. Formation of vortices and higher turbulence levels enhance the air/fuel interaction, changing the level of fuel stratification and combustion duration. Results demonstrate clearly how turbulence level correlates with heat release behavior, and provide a quantitative dataset for validation of numerical simulations.

  16. Determining How Magnetic Helicity Injection Really Works

    International Nuclear Information System (INIS)

    Paul M Bellan

    2001-01-01

    OAK-B135 The goal of the Caltech program is to determine how helicity injection works by investigating the actual dynamics and topological evolution associated with magnetic relaxation. A new coaxial helicity injection source has been constructed and brought into operation. The key feature of this source is that it has maximum geometric simplicity. Besides being important for fusion research, this work also has astrophysical implications. Photos obtained using high-speed cameras show a clear sequence of events in the formation process. In particular, they show initial merging/reconnection processes, jet-like expansion, kinking, and separation of the plasma from the source. Various diagnostics have been developed, including laser induced fluorescence and soft x-ray detection using high speed diodes. Gas valves have been improved and a patent disclosure relating to puffed gas valves has been filed. Presentations on this work have been given in the form of invited talks at several university physics departments that were previously unfamiliar with laboratory plasma experiments

  17. Performance Analysis of Multi Stage Safety Injection Tank

    International Nuclear Information System (INIS)

    Shin, Soo Jai; Kim, Young In; Bae, Youngmin; Kang, Han-Ok; Kim, Keung Koo

    2015-01-01

    In general the integral reactor has such characteristics, the integral reactor requires a high flow rate of coolant safety injection at the initial stage of the accident in which the core level is relatively fast decreased, A medium flow rate of coolant safety injection at the early and middle stages of the accident in which the coolant discharge flow rate is relatively large due to a high internal pressure of the reactor vessel, and a low flow rate of coolant safety injection is required at the middle and late stages of the accident in which the coolant discharge flow rate is greatly reduced due to a decreased pressure of the reactor vessel. It is noted that a high flow rate of the integral reactor is quite smaller compared to a flow rate required in the commercial loop type reactor. However, a nitrogen pressurized safety injection tank has been typically designed to quickly inject a high flow rate of coolant when the internal pressure of the reactor vessel is rapidly decreased, and a core makeup tank has been designed to safely inject at a single mode flow rate due to a gravitational head of water subsequent to making a pressure balance between the reactor vessel and core makeup tank. As a result, in order to compensate such a disadvantage, various type systems are used in a complicated manner in a reactor according to the required characteristic of safety injection during an accident. In the present study, we have investigated numerically the performance of the multi stage safety injection tank. A parameter study has performed to understand the characteristics of the multi stage safety injection tank. The performance of the multi stage safety injection tank has been investigated numerically. When an accident occurs, the coolant in the multi stage safety injection tank is injected into a reactor vessel by a gravitational head of water subsequent to making a pressure balance between the reactor and tank. At the early stages of the accident, the high flow rate of

  18. Performance Analysis of Multi Stage Safety Injection Tank

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Soo Jai; Kim, Young In; Bae, Youngmin; Kang, Han-Ok; Kim, Keung Koo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In general the integral reactor has such characteristics, the integral reactor requires a high flow rate of coolant safety injection at the initial stage of the accident in which the core level is relatively fast decreased, A medium flow rate of coolant safety injection at the early and middle stages of the accident in which the coolant discharge flow rate is relatively large due to a high internal pressure of the reactor vessel, and a low flow rate of coolant safety injection is required at the middle and late stages of the accident in which the coolant discharge flow rate is greatly reduced due to a decreased pressure of the reactor vessel. It is noted that a high flow rate of the integral reactor is quite smaller compared to a flow rate required in the commercial loop type reactor. However, a nitrogen pressurized safety injection tank has been typically designed to quickly inject a high flow rate of coolant when the internal pressure of the reactor vessel is rapidly decreased, and a core makeup tank has been designed to safely inject at a single mode flow rate due to a gravitational head of water subsequent to making a pressure balance between the reactor vessel and core makeup tank. As a result, in order to compensate such a disadvantage, various type systems are used in a complicated manner in a reactor according to the required characteristic of safety injection during an accident. In the present study, we have investigated numerically the performance of the multi stage safety injection tank. A parameter study has performed to understand the characteristics of the multi stage safety injection tank. The performance of the multi stage safety injection tank has been investigated numerically. When an accident occurs, the coolant in the multi stage safety injection tank is injected into a reactor vessel by a gravitational head of water subsequent to making a pressure balance between the reactor and tank. At the early stages of the accident, the high flow rate of

  19. Determinação espectrofotométrica de vitamina B2 (riboflavina) em formulações farmacêuticas empregando sistema de análises por injeção em fluxo Spectrophotometric determination of vitamin B2 (riboflavin) in pharmaceutical formulations using flow injection analysis

    OpenAIRE

    Clezio Aniceto; Larissa de Souza Canaes; Orlando Fatibello-Filho; Carla C. S. Cavalheiro

    2000-01-01

    A flow injection spectrophotometric procedure exploiting merging zones is proposed for determining vitamin B2 (riboflavin) in pharmaceutical preparations. The determination is based on the red-colored complex formation between vitamin B2 and silver(I) which was measured at 520 nm. Vitamin B2 was determined in four pharmaceutical preparations in the 1.0 to 50.0 mg L-1 concentration range, with a detection limit of 0.5 mg L-1. The recovery from three samples ranged from 98.0 to 104.0 %. The ana...

  1. STRATEGY DETERMINATION FOR DIESEL INJECTION USING AVL ESE DIESEL

    Directory of Open Access Journals (Sweden)

    Vrublevskiy, A.

    2012-06-01

    Full Text Available Based on the design of research AVL FIRE ESE DIESEL environment they proposed to reduce noise and NOx emissions in the exhaust gases of the automobile diesel engine using two-stage injection. The parameters of the fuel for idling are determined.

  2. Speciation of mercury in fish samples by flow injection catalytic cold vapour atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Zhang Yanlin; Adeloju, Samuel B.

    2012-01-01

    Highlights: ► Successful speciation of inorganic and organic Hg with Fe 3+ , Cu 2+ and thiourea as catalysts. ► Best sensitivity enhancement and similar sensitivity for MeHg and Hg 2+ with Fe 3+ . ► Successful use of Hg 2+ as the primary standard for quantification of inorganic and total-Hg. ► Quantitative extraction of Hg and MeHg with 2 M HCl which contained thiourea. ► Integration with FIA for rapid analysis with a sample throughput of 180 h −1 . - Abstract: A rapid flow injection catalytic cold vapour atomic absorption spectrometric (FI-CCV-AAS) method is described for speciation and determination of mercury in biological samples. Varying concentrations of NaBH 4 were employed for mercury vapour generation from inorganic and mixture of inorganic and organic (total) Hg. The presence of Fe 3+ , Cu 2+ and thiourea had catalytic effect on mercury vapour generation from methylmercury (MeHg) and, when together, Cu 2+ and thiourea had synergistic catalytic effect on the vapour generation. Of the two metal ions, Fe 3+ gave the best sensitivity enhancement, achieving the same sensitivity for MeHg and inorganic Hg 2+ . Due to similarity of resulting sensitivity, Hg 2+ was used successfully as a primary standard for quantification of inorganic and total Hg. The catalysis was homogeneous in nature, and it was assumed that the breaking of the C-Hg bond was facilitated by the delocalization of the 5d electron pairs in Hg atom. The extraction of MeHg and inorganic mercury (In-Hg) in fish samples were achieved quantitatively with hydrochloric acid in the presence of thiourea and determined by FI-CCV-AAS. The application of the method to the quantification of mercury species in a fish liver reference material DOLT-4 gave 91.5% and 102.3% recoveries for total and methyl mercury, respectively. The use of flow injection enabled rapid analysis with a sample throughput of 180 h −1 .

  3. Mass spectrometric confirmation criterion for product-ion spectra generated in flow-injection analysis. Environmental application

    NARCIS (Netherlands)

    Geerdink, R.B.; Niessen, W.M.A.; Brinkman, U.A.T.

    2001-01-01

    The suitability of a confirmation criterion recently recommended in the Netherlands for gas chromatography with mass spectrometric detection (GC-MS), was evaluated for flow-injection analysis (FIA) with atmospheric pressure chemical ionisation MS-MS detection. The main feature of the criterion is

  4. Determination of As(III) and total inorganic As in water samples using an on-line solid phase extraction and flow injection hydride generation atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Sigrist, Mirna; Albertengo, Antonela; Beldomenico, Horacio; Tudino, Mabel

    2011-01-01

    A simple and robust on-line sequential injection system based on solid phase extraction (SPE) coupled to a flow injection hydride generation atomic absorption spectrometer (FI-HGAAS) with a heated quartz tube atomizer (QTA) was developed and optimized for the determination of As(III) in groundwater without any kind of sample pretreatment. The method was based on the selective retention of inorganic As(V) that was carried out by passing the filtered original sample through a cartridge containing a chloride-form strong anion exchanger. Thus the most toxic form, inorganic As(III), was determined fast and directly by AsH 3 generation using 3.5 mol L -1 HCl as carrier solution and 0.35% (m/v) NaBH 4 in 0.025% NaOH as the reductant. Since the uptake of As(V) should be interfered by several anions of natural occurrence in waters, the effect of Cl - , SO 4 2- , NO 3 - , HPO 4 2- , HCO 3 - on retention was evaluated and discussed. The total soluble inorganic arsenic concentration was determined on aliquots of filtered samples acidified with concentrated HCl and pre-reduced with 5% KI-5% C 6 H 8 O 6 solution. The concentration of As(V) was calculated by difference between the total soluble inorganic arsenic and As(III) concentrations. Detection limits (LODs) of 0.5 μg L -1 and 0.6 μg L -1 for As(III) and inorganic total As, respectively, were obtained for a 500 μL sample volume. The obtained limits of detection allowed testing the water quality according to the national and international regulations. The analytical recovery for water samples spiked with As(III) ranged between 98% and 106%. The sampling throughput for As(III) determination was 60 samples h -1 . The device for groundwater sampling was especially designed for the authors. Metallic components were avoided and the contact between the sample and the atmospheric oxygen was carried to a minimum. On-field arsenic species separation was performed through the employ of a serial connection of membrane filters and

  5. Effects of Injection Timing on Fluid Flow Characteristics of Partially Premixed Combustion Based on High-Speed Particle Image Velocimetry

    KAUST Repository

    Izadi Najafabadi, Mohammad; Tanov, Slavey; Wang, Hua; Somers, Bart; Johansson, Bengt; Dam, Nico

    2017-01-01

    behavior. The scope of the present study is to investigate the fluid flow characteristics of PPC at different injection timings. To this end, high-speed Particle Image Velocimetry (PIV) is implemented in a light-duty optical engine to measure fluid flow

  6. Polyion selective polymeric membrane-based pulstrode as a detector in flow-injection analysis.

    Science.gov (United States)

    Bell-Vlasov, Andrea K; Zajda, Joanna; Eldourghamy, Ayman; Malinowska, Elzbieta; Meyerhoff, Mark E

    2014-04-15

    A method for the detection of polyions using fully reversible polyion selective polymeric membrane type pulstrodes as detectors in a flow-injection analysis (FIA) system is examined. The detection electrode consists of a plasticized polymeric membrane doped with 10 wt % of tridodecylmethylammonium-dinonylnaphthalene sulfonate (TDMA/DNNS) ion-exchanger salt. The pulse sequence used involves a short (1 s) galvanostatic pulse, an open-circuit pulse (0.5 s) during which the EMF of the cell is measured, and a longer (15 s) potentiostatic pulse to return the membrane to its original chemical composition. It is shown that total pulse sequence times can be optimized to yield reproducible real-time detection of injected samples of protamine and heparin at up to 20 samples/h. Further, it is shown that the same membrane detector can be employed for FIA detection of both polycations at levels ≥10 μg/mL and polyanions at levels of ≥40 μg/mL by changing the direction of the galvanostatic pulse. The methodology described may also be applicable in the detection of polyionic species at low levels in other flowing configurations, such as in liquid chromatography and capillary electrophoresis.

  7. Improved upper bounds on energy dissipation rates in plane Couette flow with boundary injection and suction

    Science.gov (United States)

    Lee, Harry; Wen, Baole; Doering, Charles

    2017-11-01

    The rate of viscous energy dissipation ɛ in incompressible Newtonian planar Couette flow (a horizontal shear layer) imposed with uniform boundary injection and suction is studied numerically. Specifically, fluid is steadily injected through the top plate with a constant rate at a constant angle of injection, and the same amount of fluid is sucked out vertically through the bottom plate at the same rate. This set-up leads to two control parameters, namely the angle of injection, θ, and the Reynolds number of the horizontal shear flow, Re . We numerically implement the `background field' variational problem formulated by Constantin and Doering with a one-dimensional unidirectional background field ϕ(z) , where z aligns with the distance between the plates. Computation is carried out at various levels of Re with θ = 0 , 0 .1° ,1° and 2°, respectively. The computed upper bounds on ɛ scale like Re0 as Re > 20 , 000 for each fixed θ, this agrees with Kolmogorov's hypothesis on isotropic turbulence. The outcome provides new upper bounds to ɛ among any solution to the underlying Navier-Stokes equations, and they are sharper than the analytical bounds presented in Doering et al. (2000). This research was partially supported by the NSF Award DMS-1515161, and the University of Michigan's Rackham Graduate Student Research Grant.

  8. Analysis of transient flows in gasoline direct injection systems: effects on unsteady air entrainment by the spray; Analyse des ecoulements transitoires dans les systemes d'injection directe essence: effets sur l'entrainement d'air instationnaire du spray

    Energy Technology Data Exchange (ETDEWEB)

    Delay, G.

    2005-03-15

    The aim of this study is to determine instantaneous liquid flow rate oscillations effect on non stationary air entrainment of an injector conical spray (Gasoline Direct Injection). The tools we use are either experimental or numerical ones. An instantaneous flow rate determination method is used. It is based on pulsated flows physics and only requires the velocity at the centerline of a pipe mounted just before the injector. So, it is possible to 'rebuild' the instantaneous velocity distributions and then to get the instantaneous liquid flow rate (Laser Doppler Anemometry measurements). A mechanical and hydraulics modeling software (AMESim) is necessary to get injector outlet flow rate. Simulations are validated by both 'rebuilding' method results and common rail pressure measurements. Fluorescent Particle Image Velocimetry (FPIV), suited to dense two -phase flows, is used to measure air flow around and inside the conical spray. Velocity measurements close to the spray frontier are used to compute instantaneous air entrainment. Considering droplets momentum exchange with air and thanks to droplets diameters and liquid velocities measurements at the nozzle exit, a transient air entrainment model is proposed according to FPIV measurements. (author)

  9. Arterio-venous concentration difference of [51Cr]EDTA after a single injection in man. Significance of renal function and local blood flow

    DEFF Research Database (Denmark)

    Rehling, M; Hyldstrup, L; Henriksen, Jens Henrik Sahl

    1989-01-01

    , whereas the difference was very sensitive to even small changes in forearm blood flow within the physiological range. For measurement of renal plasma clearance it is recommended to use one long period: from the time of injection until 300 min p.i. or longer. If the clearance period is too short, the use...... introduced in the measurement of renal plasma clearance and total plasma clearance by using venous blood samples instead of arterial. In 13 patients with GFR ranging from 29 to 150 ml min-1, Ca was higher than Cv immediately after the injection. After mean 38 min (range 12-82 min) the two curves crossed...... of venous samples will overestimate the true renal clearance. Plasma clearance determined by venous and arterial blood samples does not differ significantly as long as the concentration is followed from the time of injection and a long period is applied. When simplified plasma clearance techniques are used...

  10. Determination of Total Selenium in Infant Formulas: Comparison of the Performance of FIA and MCFA Flow Systems

    Directory of Open Access Journals (Sweden)

    Mariela Pistón

    2012-01-01

    Full Text Available Two flow methods, based, respectively, on flow-injection analysis (FIA and on multicommutated flow analysis (MCFA, were compared with regard to their use for the determination of total selenium in infant formulas by hydride-generation atomic absorption spectrometry. The method based on multicommutation provided lower detection and quantification limits (0.08 and 0.27 μg L−1 compared to 0.59 and 1.95 μ L−1, resp., higher sampling frequency (160 versus. 70 samples per hour, and reduced reagent consumption. Linearity, precision, and accuracy were similar for the two methods compared. It was concluded that, while both methods proved to be appropriate for the purpose, the MCFA-based method exhibited a better performance.

  11. Effects of GC temperature and carrier gas flow rate on on-line oxygen isotope measurement as studied by on-column CO injection.

    Science.gov (United States)

    Chen, Zhi-Gang; Yin, Xi-Jie; Zhou, Youping

    2015-08-01

    Although deemed important to δ 18 O measurement by on-line high-temperature conversion techniques, how the GC conditions affect δ 18 O measurement is rarely examined adequately. We therefore directly injected different volumes of CO or CO-N 2 mix onto the GC column by a six-port valve and examined the CO yield, CO peak shape, CO-N 2 separation, and δ 18 O value under different GC temperatures and carrier gas flow rates. The results show the CO peak area decreases when the carrier gas flow rate increases. The GC temperature has no effect on peak area. The peak width increases with the increase of CO injection volume but decreases with the increase of GC temperature and carrier gas flow rate. The peak intensity increases with the increase of GC temperature and CO injection volume but decreases with the increase of carrier gas flow rate. The peak separation time between N 2 and CO decreases with an increase of GC temperature and carrier gas flow rate. δ 18 O value decreases with the increase of CO injection volume (when half m/z 28 intensity is rate. On average, the δ 18 O value of the injected CO is about 1‰ higher than that of identical reference CO. The δ 18 O distribution pattern of the injected CO is probably a combined result of ion source nonlinearity and preferential loss of C 16 O or oxygen isotopic exchange between zeolite and CO. For practical application, a lower carrier gas flow rate is therefore recommended as it has the combined advantages of higher CO yield, better N 2 -CO separation, lower He consumption, and insignificant effect on δ 18 O value, while a higher-than-60 °C GC temperature and a larger-than-100 µl CO volume is also recommended. When no N 2 peak is expected, a higher GC temperature is recommended, and vice versa. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Heat and mass transfer in the stratified flow with ECCS injection

    International Nuclear Information System (INIS)

    Strubelj, L.; Tiselj, I.

    2007-01-01

    One of the most important problems in the light-water nuclear thermal-hydraulics is behaviour of the cold emergency core cooling water injected from the top or from the bottom into the horizontal section of the cold leg near the reactor vessel during the loss of coolant accident. The stratified flows appear where cold water is injected in partially or fully uncovered horizontal cold leg. The hot steam condenses on cold water surface what is also called direct contact condensation. Direct contact condensation and condensation induced water-hammer in a horizontal pipe were experimentally investigated at PMK-2 test facility of the Hungarian Atomic Energy Research Institute KFKI. The cold water is injected through small pipe into lower horizontal part of the section, and then water fills the vertical pipeline and floods the horizontal test section of the pipeline of the PMK-2 integral test facility. As liquid water floods the horizontal part of the pipeline, the counter current horizontally stratified flow is being observed. During the flooding of the pipeline, the steam-liquid interface area increases and therefore the steam condensation rate and the steam velocity also increase and can lead to bubble entrapment. Water level at one cross-section and four local void fraction and temperature at the top of horizontal test pipeline was measured and compared with simulation. Condensed steam increases the water temperature that is why the local temperature measurements are the most important information, from which condensation rate can be estimated, since mass of condensed steam was not measured. Numerical simulation of the experiment with thermal phase change is presented. Surface renewal concept with small eddies is used for calculation of condensation heat transfer coefficient. Two simulations were performed: simulation of whole experimental domain (lower horizontal, vertical and test horizontal pipeline) and simplified simulation of only upper horizontal test section

  13. Potentiometric flow injection system for determination of reductants using a polymeric membrane permanganate ion-selective electrode based on current-controlled reagent delivery.

    Science.gov (United States)

    Song, Wenjing; Ding, Jiawang; Liang, Rongning; Qin, Wei

    2011-10-17

    A polymeric membrane permanganate-selective electrode has been developed as a current-controlled reagent release system for potentiometric detection of reductants in flow injection analysis. By applying an external current, diffusion of permanganate ions across the polymeric membrane can be controlled precisely. The permanganate ions released at the sample-membrane interface from the inner filling solution of the electrode are consumed by reaction with a reductant in the sample solution thus changing the measured membrane potential, by which the reductant can be sensed potentiometrically. Ascorbate, dopamine and norepinephrine have been employed as the model reductants. Under the optimized conditions, the potential peak heights are proportional to the reductant concentrations in the ranges of 1.0×10(-5) to 2.5×10(-7)M for ascorbate, of 1.0×10(-5) to 5.0×10(-7)M for dopamine, and of 1.0×10(-5) to 5.0×10(-7)M for norepinephrine, respectively with the corresponding detection limits of 7.8×10(-8), 1.0×10(-7) and 1.0×10(-7)M. The proposed system has been successfully applied to the determination of reductants in pharmaceutical preparations and vegetables, and the results agree well with those of iodimetric analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. On-line dynamic extraction and automated determination of readily bioavailable hexavalent chromium in solid substrates using micro-sequential injection bead-injection lab-on-valve hyphenated with electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2006-01-01

    A novel and miniaturized micro-sequential injection bead injection lab-on-valve (μSI-BI-LOV) fractionation system was developed for in-line microcolumn soil extraction under simulated environmental scenarios and accurate monitoring of the content of easily mobilisable hexavalent chromium in soil...... environments at the sub-low parts-per-million level. The flow system integrates dynamic leaching of hexavalent chromium using deionized water as recommended by the German Standard DIN 38414-S4 method; on-line pH adjustment of the extract by a 0.01 mol L-1 Tris-HNO3 buffer solution; isolation of the chromate...... polluted agricultural soil material (San Joaquin Soil-Baseline Trace Element Concentrations) with water-soluble Cr(VI) salts at different concentration levels. The potential of the μSI-BI-LOV set-up with renewable surfaces for flame-AAS determination of high levels of readily bioavailable chromate...

  15. Evaluation of Antibacterial Enrofloxacin in Eggs by Matrix Solid Phase Dispersion-Flow Injection Chemiluminescence

    Directory of Open Access Journals (Sweden)

    Xiaocui Duan

    2014-01-01

    Full Text Available The study based on the chemiluminescence (CL reaction of potassium ferricyanide and luminol in sodium hydroxide medium, enrofloxacin (ENRO could dramatically enhance CL intensities and incorporated with matrix solid-phase dispersion (MSPD technique (Florisil used as dispersant, dichloromethane eluted the target compounds. A simple flow injection chemiluminescence (FL-CL method with MSPD technique for determination of ENRO in eggs was described. Under optimal conditions, the CL intensities were linearly related to ENRO concentration ranging from 4.0×10-8 g.L−1 to 5.0×10-5 g.L−1, with a correlation coefficient of 0.9989 and detection limit of 5.0×10-9 g.L−1. The relative standard deviation was 3.6% at an ENRO concentration of 2.0×10-6 g.L−1. Our testing technique can help ensure food safety, and thus, protect public health.

  16. Direct Zinc Determination in Brazilian Sugar Cane Spirit by Solid-Phase Extraction Using Moringa oleifera Husks in a Flow System with Detection by FAAS

    OpenAIRE

    Alves, Vanessa N.; Borges, Simone S. O.; Coelho, Nivia M. M.

    2011-01-01

    This paper reports a method for the determination of zinc in Brazilian sugar cane spirit, (cachaça in Portuguese), using solid-phase extraction with a flow injection analysis system and detection by FAAS. The sorbent material used was activated carbon obtained from Moringa oleifera husks. Flow and chemical variables of the proposed system were optimized through multivariate designs. The factors selected were sorbent mass, sample pH, sample flow rate, and eluent concentration. The optimum extr...

  17. An investigation of fluid mixing with safety injection in advanced reactors

    International Nuclear Information System (INIS)

    Cha, Jong Hee; Won, Soon Yean; Chung, Moon Ki; Jun, Hyung Gil

    1994-01-01

    The objective of this work is to investigate the fluid mixing phenomena in aspect of pressurized thermal shock(PTS) in an advanced PWR vessel downcomer during transient cooldown with safety injection. It provides comparison of fluid mixing characteristics between AP 600 DVI, designed by Westinghouse, and ABB CE System 80+ DVI, and the effects of deflector at the reactor downcomer. In order to investigate the fluid mixing phenomena in the downcomer of an advanced PWR, the flow visualization tests and the salt concentration tests were conducted in a 1/7-scale acrylic transparent model, which was designed and built based on AP 600 reactor geometry. The behaviour of the safety injection flow in downcomer associated with mixing phenomenon can be observed during visualization test, and time-dependent mixing rate between safety injection fluid and existing coolant can be determined with concentration test. Visualization tests were performed by the dye injection method. The results of concentration measurements were compared with the calculation using the REMIX code. During the tests, difference between AP 600 DVI flow and ABB CE System 80+ DVI flow and the effect of the deflector were observed

  18. Cavitating flow control through continuous tangential mass injection on a 2D hydrofoil at a small attack angle

    Directory of Open Access Journals (Sweden)

    Timoshevskiy Mikhail V.

    2016-01-01

    Full Text Available We studied cavitating flow over the suction side of a symmetric 2D foil – a scaled-down model of high-pressure hydroturbine guide vanes (GV – in different cavitation regimes at the attack angle of 3°. High-speed imaging was used to analyze spatial patterns and time dynamics of the gas-vapour cavities. A hydroacoustic pressure transducer was employed to register time-spectra of pressure fluctuations nearby the hydrofoil. A PIV technique was applied to measure the velocity fields and its fluctuations. The active flow control was implemented by means of a continuous liquid supply with different flow rates through a slot channel located in the GV surface. It was found that the active mass injection does not influence the primary flow upstream of the slot channel position. For the cavitation-free and cavitation inception cases, the injection was shown to make the turbulent wake past the GV section more intense. However, at the developed cavitation regimes the active flow management made it possible to reduce substantially the amplitude or even totally suppress the periodic cavity length oscillations and pressure pulsations associated with them.

  19. Numerical Simulation of Magnetic Nanoparticles Injection into Two–phase Flow in a Porous Medium

    KAUST Repository

    El-Amin, Mohamed

    2017-06-09

    In this paper, the problem of magnetic nanoparticles injection into a water–oil two–phase flow under an external permanent magnetic field is investigated. The mathematical model of the problem under consideration has been developed. We treat the water-nanoparticles suspension as a miscible mixture while it is immiscible with the oil phase. The magnetized phase pressure includes an additional pressure term with the conventional thermodynamic pressure. The countercurrent imbibition flow problem is taken as an example. Physical variables including water–nanoparticles suspension saturation, nanoparticles concentration, and pore wall/throat deposited nanoparticles are investigated under the influence of the magnetic field.

  20. Effect of gas field production and CO2 injection on brine flow and salt precipitation

    NARCIS (Netherlands)

    Loeve, D.; Tambach, T.J.; Hofstee, C.; Plug, W.J.; Maas, J.

    2012-01-01

    This paper reports modeling of gas field produc-tion and CO2 injection from a theoretical reser-voir based on characteristics of the P18 gas field in the Dutch offshore, which consists of four geological deposits with different petrophysical properties. We especially focus on the brine flow during

  1. Reverse radiometric flow injection analysis (RFIA) of radioactive waste-waters with an ASIA (Ismatec) analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Myint, U; Win, N; San, K; Han, B; Myoe, K M [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

    1994-07-01

    A new application of reverse radiometric flow injection analysis is described. RFIA was used for the analysis of radioactive wastewaters. ASIA (Ismatec) analyzer with NaI(Tl) scintillation detector was used in the study of analysis of [sup 131]I containing waste-aster. (author) 4 refs.; 3 figs.

  2. Comparison of the samples injection systems with ultrasonic nebulizer and with pneumatic nebulizer for the metal determination in water by inductively coupled plasma optical emission spectrometry

    International Nuclear Information System (INIS)

    Marin, Sergio R; Pismante, Paola A

    2005-01-01

    The natural waters, depending on their use, must fulfill the exigencies and requirements that fix national and international norms. These establish conditions with respect to the concentration levels that must be some metals. In this work the development of inductively coupled plasma emission optical spectrometry with ultrasonic injection system is presented. The determination of aluminum, arsenic, barium, cadmium, zinc, cobalt, chromium, copper, iron, manganese, molybdenum, nickel, lead, strontium and vanadium, at levels of ultra-trace in water samples is studied by this technique. The wavelengths that represented better sensitivity and minors spectral interferences, were selected from the Literature specialized in the analysis of this type of material. Also the conditions of work for the ultrasonic nebulization: temperature, pressure, flow speed of argon, and flow speed of sample was determined. The greater sensitivity of the injection system by ultrasonic nebulization forehead to the injection system by pneumatic nebulization, is verified when comparing the spectral intensity of the selected wavelengths. Also the limits of detection and quantification was obtained by both systems. The validity of the results obtained in this method is verified applying the test of Fisher, who determines the degree of homogeneity of the variances, and the test of Student, to determine the trazability obtained with these values. For these studies, the certified material of reference TM-24.2 of National Water Research Institute Environment Canada (NWRI), was used. The positive answer to the criteria of evaluation E and Z-Score, obtained by this technique, allows to verify that it fulfills the exigencies to be used in the determination of metals at the required levels (au)

  3. Capillary permeability of 99mTc-DTPA and blood flow rate in the human myocardium determined by intracoronary bolus injection and residue detection

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Efsen, F; Haunsø, S

    1992-01-01

    .7 ml.(100 g.min)-1 (SD 13.0). Similar values of blood flow rate, capillary extraction fraction and the PS product were determined in 6 patients with localized coronary atheroma without hemodynamically significant coronary artery stenosis (25-50% luminal narrowing). The values for the regional......The aims of the present study were to quantitate blood flow rate and capillary permeability of 99mTc-DTPA in the human myocardium and to assess whether capillary permeability is influenced by the presence of small degree atherosclerotic lesions. Myocardial blood flow rate and capillary permeability......, a mean value of the capillary permeability-surface area (PS) product of 54.0 ml.(100 g.min)-1 (SD 13.0) was determined from a capillary extraction of 55.0% (SD 9.4%) and a regional myocardial plasma flow rate of 74.6 ml.(100 g.min)-1 (SD 6.3) equivalent with a regional myocardial blood flow rate of 121...

  4. Simple technique for measuring relative renal blood flow

    International Nuclear Information System (INIS)

    Shames, D.M.; Korobkin, M.

    1976-01-01

    To determine whether externally monitored early renal uptake of 131 I-hippurate is proportional to renal blood flow, the renal uptake of 131 -hippurate at 1 to 2 min after injection was compared with the renal accumulation of radioactive carbonized microspheres in dogs. A renal artery catheter equipped with a balloon was used to decrease renal blood flow unilaterally. One minute after the intravenous injection of 100 μCi of 131 I-hippurate, about 1 μCi of either 85 Sr- or 95 Nb-labeled carbon microspheres was injected into the left ventricle. Radioactivity was measured over both kidneys. The total radioactivity within each kidney region of interest was corrected for background and integrated over the 1 to 2 min interval after injection. Thirteen measurements of relative renal blood flow were made for seven dogs. The dogs were then killed and both kidneys were excised and counted for the radioactivity of the microspheres. The 1 to 2-min relative renal uptake of 131 I-hippurate correlated well with relative microsphere uptake, suggesting that relative renal blood flow can be simply determined from the external measurements of renal uptake of 131 I-hippurate

  5. On-line monitoring of glucose and/or lactate in a fermentation process using an expanded micro-bed flow injection analyser.

    Science.gov (United States)

    Nandakumar, M P; Lali, A M; Mattiasson, B

    1999-01-01

    A novel flow injection biosensor system for monitoring fermentation processes has been developed using an expanded micro bed as the enzyme reactor. An expanded bed reactor is capable of handling a mobile phase containing suspended matter like cells and cell debris. Thus, while the analyte is free to interact with the adsorbent, the suspended particulate matter passes through unhindered. With the use of a scaled down expanded bed in the flow injection analysis (FIA) system, it was possible to analyse samples directly from a fermentor without the pretreatment otherwise required to extract the analyte or remove the suspended cells. This technique, therefore, provides a means to determine the true concentrations of the metabolites in a fermentor, with more ease than possible with other techniques. Glucose oxidase immobilised on STREAMLINE was used to measure glucose concentration in a suspension of dead yeast cells. There was no interference from the cell particles even at high cell densities such as 15 gm dry weight per litre. The assay time was about 6 min. Accuracy and reproducibility of the system was found to be good. In another scheme, lactate oxidase was covalently coupled to STREAMLINE for expanded bed operation. With the on-line expanded micro bed FIA it was possible to follow the fermentation with Lactobacillus casei.

  6. Determination of inorganic mercury and total mercury in biological and environmental samples by flow injection-cold vapor-atomic absorption spectrometry using sodium borohydride as the sole reducing agent

    International Nuclear Information System (INIS)

    Rio Segade, Susana; Tyson, Julian F.

    2003-01-01

    A simple, fast, precise and accurate method to determine inorganic mercury and total mercury in biological and environmental samples was developed. The optimized flow-injection mercury system permitted the separate determination of inorganic mercury and total mercury using sodium borohydride as reducing agent. Inorganic mercury was selectively determined after reduction with 10 -4 % w/v sodium borohydride, while total mercury was determined after reduction with 0.75% w/v sodium borohydride. The calibration graphs were linear up to 30 ng ml -1 . The detection limits of the method based on three times the standard deviation of the blank were 24 and 3.9 ng l -1 for total mercury and inorganic mercury determination, respectively. The relative standard deviation was less than 1.5% for a 10 ng ml -1 mercury standard. As a means of checking method performance, deionized water and pond water samples were spiked with methylmercury and inorganic mercury; quantitative recovery for total mercury and inorganic mercury was obtained. The accuracy of the method was verified by analyzing alkaline and acid extracts of five biological and sediment reference materials. Microwave-assisted extraction procedures resulted in higher concentrations of recovered mercury species, lower matrix interference with mercury determination and less time involved in sample treatment than conventional extraction procedures. The standard addition method was only needed for calibration when biological samples were analyzed. The detection limits were in the range of 1.2-19 and 6.6-18 ng g -1 in biological and sediment samples for inorganic mercury and total mercury determination, respectively

  7. Transmicrocatheter local injection of ethanol to treat hepatocellular carcinoma with high flow arteriovenous shunts

    International Nuclear Information System (INIS)

    Guan Shouhai; Shan Hong; Jiang Zaibo; Huang Mingsheng; Zhu Kangshun; Li Zhengran; Meng Xiaochun

    2002-01-01

    Objective: To evaluate the feasibility and clinical effect of embolization therapy in treating the high flow hepatic arteriovenous shunts in hepatocellular carcinoma (HCC) by locally injected ethanol through microcatheter. Methods: Forty-one branches of arteriovenous shunts were treated by local ethanol infusion through microcatheter in 29 patients suffered with HCC. Angiography was performed to observe the embolization effect and influence to non-targeted vessels. Result: Forty-one branches of arteriovenous shunts in 29 patients were injected with ethanol locally. Each single shunt was infused 1-6 times. The dose of ethanol was 2-3 ml per time, and the total dose of ethanol was 2-12 ml. All shunting tracts were embolized, and all non-target vessels were protected fluently. Iodine-oil deposition was well in continued TACE. Their syndromes were improved or disappeared. Conclusion: Transmicrocatheter injection of ethanol could safely and effectively treat the hepatic arteriovenous shunts and make advantages to TACE in HCC

  8. Estimation of the quantification uncertainty from flow injection and liquid chromatography transient signals in inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Laborda, Francisco; Medrano, Jesus; Castillo, Juan R.

    2004-01-01

    The quality of the quantitative results obtained from transient signals in high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) and flow injection-inductively coupled plasma mass spectrometry (FI-ICPMS) was investigated under multielement conditions. Quantification methods were based on multiple-point calibration by simple and weighted linear regression, and double-point calibration (measurement of the baseline and one standard). An uncertainty model, which includes the main sources of uncertainty from FI-ICPMS and HPLC-ICPMS (signal measurement, sample flow rate and injection volume), was developed to estimate peak area uncertainties and statistical weights used in weighted linear regression. The behaviour of the ICPMS instrument was characterized in order to be considered in the model, concluding that the instrument works as a concentration detector when it is used to monitorize transient signals from flow injection or chromatographic separations. Proper quantification by the three calibration methods was achieved when compared to reference materials, although the double-point calibration allowed to obtain results of the same quality as the multiple-point calibration, shortening the calibration time. Relative expanded uncertainties ranged from 10-20% for concentrations around the LOQ to 5% for concentrations higher than 100 times the LOQ

  9. Determination of drugs in biological fluids by direct injection of samples for liquid-chromatographic analysis.

    Science.gov (United States)

    Mullett, Wayne M

    2007-03-10

    The analysis of drugs in various biological fluids is an important criterion for the determination of the physiological performance of a drug. After sampling of the biological fluid, the next step in the analytical process is sample preparation. The complexity of biological fluids adds to the challenge of direct determination of the drug by chromatographic analysis, therefore demanding a sample preparation step that is often time-consuming, tedious, and frequently overlooked. However, direct on-line injection methods offer the advantage of reducing sample preparation steps and enabling effective pre-concentration and clean-up of biological fluids. These procedures can be automated and therefore reduce the requirements for handling potentially infectious biomaterial, improve reproducibility, and minimize sample manipulations and potential contamination. The objective of this review is to present an overview of the existing literature with emphasis on advances in automated sample preparation methods for liquid-chromatographic methods. More specifically, this review concentrates on the use of direct injection techniques, such as restricted-access materials, turbulent-flow chromatography and other automated on-line solid-phase extraction (SPE) procedures. It also includes short overviews of emerging automated extraction-phase technologies, such as molecularly imprinted polymers, in-tube solid-phase micro-extraction, and micro-extraction in a packed syringe for a more selective extraction of analytes from complex samples, providing further improvements in the analysis of biological materials. Lastly, the outlook for these methods and potential new applications for these technologies are briefly discussed.

  10. Flow injection microfluidic device with on-line fluorescent derivatization for the determination of Cr(III) and Cr(VI) in water samples after solid phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Guilong [Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, 400045 (China); Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084 (China); He, Qiang, E-mail: heqiang0980@163.com [Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, 400045 (China); Lu, Ying [Department of Mathematics and Physics, Armed Police College, Chengdu, 610213 (China); Huang, Jing [Research Center for Advanced Computation, College of Science, Xihua University, Chengdu, 610039 (China); Lin, Jin-Ming, E-mail: jmlin@mail.tsinghua.edu.cn [Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084 (China)

    2017-02-22

    In this paper, a rapid and simple method using magnetic multi-walled carbon nanotubes (MWCNTS), as a solid-phase extraction (SPE) sorbent, was successfully developed for extraction and preconcentration trace amounts of Cr(III) in water samples. The synthesized magnetic-MWCNTs nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). A rhodamine derivative (R1) was synthesized and characterized as a highly selective and sensitive fluorescent derivatizing agent for Cr(III). After SPE procedure, Cr(III) analysis was performed by flow injection microfluidic chip with on-line fluorescent derivatization and laser-induced fluorescence (LIF) spectroscopy detection. The parameters, which affected the efficiency of the developed method were investigated and optimized. Under the optimized conditions, the method exhibited a linear dynamic range of 0–10.0 nM, with a detection limit of 0.094 nM and an enrichment factor of 38. Furthermore, real water samples were analyzed and good recoveries were obtained from 91.0 to 101.6%. - Graphical abstract: Flow injection microfluidic device with on-line fluorescent derivatization and detection coupled to LIF. - Highlights: • A highly selective and sensitive derivatizing reagent for Cr(III) was synthesized and characterized. • The magnetic-MWCNTs nanocomposite as a SPE sorbent was successfully synthesized and characterized. • A new portable detection system was developed for microfluidic chip FIA platform.

  11. A two-fluid model for vertical flow applied to CO2 injection wells

    DEFF Research Database (Denmark)

    Linga, Gaute; Lund, Halvor

    2016-01-01

    Flow of CO2 in wells is associated with substantial variations in thermophysical properties downhole, due to the coupled transient processes involved: complex flow patterns, density changes, phase transitions, and heat transfer to and from surroundings. Large temperature variations can lead...... the well, including tubing, packer fluid, casing, cement or drilling mud, and rock formation. This enables prediction of the temperature in the well fluid and in each layer of the well. The model is applied to sudden shut-in and blowout cases of a CO2 injection well, where we employ the highly accurate...

  12. Small-Volume Injections: Evaluation of Volume Administration Deviation From Intended Injection Volumes.

    Science.gov (United States)

    Muffly, Matthew K; Chen, Michael I; Claure, Rebecca E; Drover, David R; Efron, Bradley; Fitch, William L; Hammer, Gregory B

    2017-10-01

    In the perioperative period, anesthesiologists and postanesthesia care unit (PACU) nurses routinely prepare and administer small-volume IV injections, yet the accuracy of delivered medication volumes in this setting has not been described. In this ex vivo study, we sought to characterize the degree to which small-volume injections (≤0.5 mL) deviated from the intended injection volumes among a group of pediatric anesthesiologists and pediatric postanesthesia care unit (PACU) nurses. We hypothesized that as the intended injection volumes decreased, the deviation from those intended injection volumes would increase. Ten attending pediatric anesthesiologists and 10 pediatric PACU nurses each performed a series of 10 injections into a simulated patient IV setup. Practitioners used separate 1-mL tuberculin syringes with removable 18-gauge needles (Becton-Dickinson & Company, Franklin Lakes, NJ) to aspirate 5 different volumes (0.025, 0.05, 0.1, 0.25, and 0.5 mL) of 0.25 mM Lucifer Yellow (LY) fluorescent dye constituted in saline (Sigma Aldrich, St. Louis, MO) from a rubber-stoppered vial. Each participant then injected the specified volume of LY fluorescent dye via a 3-way stopcock into IV tubing with free-flowing 0.9% sodium chloride (10 mL/min). The injected volume of LY fluorescent dye and 0.9% sodium chloride then drained into a collection vial for laboratory analysis. Microplate fluorescence wavelength detection (Infinite M1000; Tecan, Mannedorf, Switzerland) was used to measure the fluorescence of the collected fluid. Administered injection volumes were calculated based on the fluorescence of the collected fluid using a calibration curve of known LY volumes and associated fluorescence.To determine whether deviation of the administered volumes from the intended injection volumes increased at lower injection volumes, we compared the proportional injection volume error (loge [administered volume/intended volume]) for each of the 5 injection volumes using a linear

  13. Adaptation of a load-inject valve for a flow injection chemiluminescence system enabling dual-reagent injection enhances understanding of environmental Fenton chemistry

    International Nuclear Information System (INIS)

    Jones, Matthew R.; Nightingale, Philp D.; Turner, Suzanne M.; Liss, Peter S.

    2013-01-01

    Graphical abstract: -- Highlights: •Measurement of multiple components of Fenton chemistry; Fe(II) and H 2 O 2 . •Rapid, quasi-simultaneous analysis enables calculation of environmental kinetics. •Low, nano to pico-molar detection limits with dual analyte analysis. •Able to measure complex matrix samples – organically enriched seawater. •Low cost system with appreciable sensitivity compared to single analyte analysis. -- Abstract: Environmental Fenton chemistry has been poorly constrained within the marine environment at a multi-component level. A simple, unique, reconfiguration of a flow-injection analytical system combined with luminol chemiluminescence allows quasi-simultaneously the measurement, using a single load-inject valve and a single photon multiplier tube, of reduced iron, Fe(II), and hydrogen peroxide. The system enables rapid, every 22 s, measurements with good accuracy at environmentally relevant concentrations, less than 5% relative standard deviations on both a 5 nM Fe(II) standard and a 60 nM hydrogen peroxide standard. Limits of detection were as low as 40 pM Fe(II) and 100 pM hydrogen peroxide. The system showed excellent capability by measuring from within an organic rich seawater the photochemically induced production of Fe(II) and hydrogen peroxide and their subsequent cycling and Fenton like interactions

  14. Determination of skin blood flow by 133Xe washout and by heat flux from a heated tc-Po2 electrode

    International Nuclear Information System (INIS)

    Jaszczak, P.; Sejrsen, P.

    1984-01-01

    133 Xe washout measurements were used to determine cutaneous and subcutaneous blood flow beneath a specially designed double-thermostated tc-Po 2 electrode. The skin blood flow was determined using thermal methods based on reduced heat dissipation during blood flow cessation. A total of 20 measurements were performed on two healthy volunteers, using the volar side of the right forearm as the experimental area. Cutaneous as well as subcutaneous blood flow increased with increasing electrode temperature. The cutaneous blood flow increased from 12.3 +- 1.3 ml (100 g) -1 . min -1 (37degC) to 49.1 +- 5.4 ml (100g) -1 . min -1 (45degC) and the subcutaneous values from 20.9 +- 0.2 ml (100 g) -1 . min -1 to 57.3 +- 0.5 ml(100 g) -1 . min -1 . Preheating of the measuring area or injection of papaverine as blood flow accelerator did not increase the maximum blood flow values. A considerable inter-individual difference between cutaneous and subcutaneous blood flow was observed, but in spite of that a good overall correlation between the 133 Xe washout measurements and the two thermal flow measurements was found (r = 0.932 and 0.945, respectively). It is concluded that in some cases, but not always, measurements of tc-Po 2 at electrode temperatures of 45degC take place on a maximally perfused skin and that it is possible to determine skin blood flow by means of determinations of the heat dissipated from the tc-Po 2 electrode to the underlying skin. (author)

  15. Determination of hepatic fractional clearance of radioactive gold colloids for a measure of effective hepatic blood flow

    International Nuclear Information System (INIS)

    Fujii, Masahiro

    1979-01-01

    For a measure of effective blood flow, a hepatic fractional clearance of 198 Au-colloids was determined, which was obtained from the disappearance rate multiplied by the fraction of injected dose taken up by the liver. The hepatic uptake was determined with a gamma camera. The counts over the liver was corrected for body weight and height. The method was considered sufficiently simple for routine use. 198 Au-colloids were obtained from Dainabot Lab. and CIS. The former gave 64% higher values of disappearance rate than the latter, without any change in the organ distribution. A quality control tests were applied over a six-year period to the disappearance rates. Reproducibility within 95 to confidence limits was found for both groups. In 28 normal control subjects, hepatic fractional clearance of the colloids from Dainabot Lab. was 18.5 +- 3.4%/min. In patients with progressed hepatic disease, both hepatic fractional clearance and final hepatic uptake were decreased, showing that the determination of hepatic uptake is necessary in measuring effective hepatic blood flow by the colloidal clearance method. The influence of splenic uptake is discussed in relation to hepatic blood flow measurement. (author)

  16. Cerebral blood flow in the occlusive cerebrovascular disease. 133Xe intravenous injection method

    Energy Technology Data Exchange (ETDEWEB)

    Kuda, Hitoshi; Mukawa, Jiro; Takara, Eiichi; Kinjo, Toshihiko; Ishikawa, Yasunari

    1988-04-01

    From December 1985 to May 1986, cerebral blood flow (CBF) was studied in 11 patients with occlusive cerebrovascular diseases confined by angiography. 133Xe (5mci) intravenous injection method designed by Kuikka and coworkers was applied for the measurement of regional-CBF and mean-CBF, and the calculation was based on the initial slope index. They were composed of 4 patients of the middle cerebral artery occlusion, 2 of the posterior cerebral artery occlusion, 1 of the internal carotid artery occlusion, 2 of the middle cerebral artery stenosis, 1 of the internal carotid artery stenosis, and 1 of the anterior cerebral artery stenosis. The period from the vascular attack to the initial CBF study was 2-29 days(mean 9.2 days). Recovery of mean-CBF was correlated with clinical and neurological improvement, and vice versa. There was no correlation between mean-CBF and neurological severity. CBF study alone is not sufficient to evaluate neuronal conditions in the occlusive disease. Additional other means, such as CT-scan, angiography and etc. should be requested for it. Intravenous 133Xe injection technique has an advantage over intracarotid injection method; less dangerous, especially in ages and capable of simultaneous measurement of bilateral hemisphere. Considering /sup c/ross talk/sup /regional-CBF of a low density area on X-ray CT-scan was equal to the one obtained by intracarotid injection method.

  17. Determination of As(III) and total inorganic As in water samples using an on-line solid phase extraction and flow injection hydride generation atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sigrist, Mirna, E-mail: msigrist@fiq.unl.edu.ar [Laboratorio Central, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2654-Piso 6, (3000) Santa Fe (Argentina); Albertengo, Antonela; Beldomenico, Horacio [Laboratorio Central, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2654-Piso 6, (3000) Santa Fe (Argentina); Tudino, Mabel [Laboratorio de Analisis de Trazas, Departamento de Quimica Inorganica, Analitica y Quimica Fisica/INQUIMAE, Facultad de Ciencias Exactas y Naturales, Pabellon II, Ciudad Universitaria (1428), Buenos Aires (Argentina)

    2011-04-15

    A simple and robust on-line sequential injection system based on solid phase extraction (SPE) coupled to a flow injection hydride generation atomic absorption spectrometer (FI-HGAAS) with a heated quartz tube atomizer (QTA) was developed and optimized for the determination of As(III) in groundwater without any kind of sample pretreatment. The method was based on the selective retention of inorganic As(V) that was carried out by passing the filtered original sample through a cartridge containing a chloride-form strong anion exchanger. Thus the most toxic form, inorganic As(III), was determined fast and directly by AsH{sub 3} generation using 3.5 mol L{sup -1} HCl as carrier solution and 0.35% (m/v) NaBH{sub 4} in 0.025% NaOH as the reductant. Since the uptake of As(V) should be interfered by several anions of natural occurrence in waters, the effect of Cl{sup -}, SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, HPO{sub 4}{sup 2-}, HCO{sub 3}{sup -} on retention was evaluated and discussed. The total soluble inorganic arsenic concentration was determined on aliquots of filtered samples acidified with concentrated HCl and pre-reduced with 5% KI-5% C{sub 6}H{sub 8}O{sub 6} solution. The concentration of As(V) was calculated by difference between the total soluble inorganic arsenic and As(III) concentrations. Detection limits (LODs) of 0.5 {mu}g L{sup -1} and 0.6 {mu}g L{sup -1} for As(III) and inorganic total As, respectively, were obtained for a 500 {mu}L sample volume. The obtained limits of detection allowed testing the water quality according to the national and international regulations. The analytical recovery for water samples spiked with As(III) ranged between 98% and 106%. The sampling throughput for As(III) determination was 60 samples h{sup -1}. The device for groundwater sampling was especially designed for the authors. Metallic components were avoided and the contact between the sample and the atmospheric oxygen was carried to a minimum. On-field arsenic species

  18. Regional cerebral blod flow studied by xenon-133. Intra-arterial injection studies and inhalation studies using emission tomography

    DEFF Research Database (Denmark)

    Lassen, N A

    1980-01-01

    .) technique is insensitive both to hyperemia and ischemia yielding essentially only a mean flow value. A new rapidly moving single photon tomograph following D. Kuhl's principle is presented applicable to Xe-133. Preliminary clinical data show that this technique is able to detect ischemic areas both with Xe......A survey of the Xenon-133 techniques for measurement of regional cerebral blood flow, rCBF, in man is presented. The intra-arterial Xe-133 injection method is very sensitive for detecting even small hyperemic areas, but cannot "see" smaller ischemic areas. The Xe-133 inhalation (or i.v. inj......-133 intra-arterial injection and with Xe-133 inhalation. The practical and economic advantages of Xe-133 or Xe-127 tomography over positron tomography for rCBF are discussed....

  19. Online preconcentration and determination of trace levels cadmium in water samples using flow injection systems coupled with flame AAS

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Songlin; Liang, Huading; Yan, Hua; Yan, Zhengzhong; Chen, Suqing; Zhu, Xiandi; Cheng, Miaoxian [School of Pharmaceutical and Chemical Engineering, Taizhou University (China)

    2010-02-15

    A rapid and sensitive method for the determination of trace levels cadmium in water samples by flame atomic absorption spectrometry was developed. It is based on the online sorption of Cd(II) ions on a microcolumn packed with HCl treated bamboo charcoal. In a pH range of 5.0-7.5, Cd(II) ions were effectively retained on the microcolumn, which exhibited fast kinetics, permitting the use of high sample flow rates up to at least 12.8 mL/min without the loss of retention efficiency. The retained Cd(II) ions were quantitatively eluted with HCl (2.0 mol/L) for an online determination. With a preconcentration time of 80 s at a sample loading flow rate of 8.6 mL/min, a sensitivity enhancement factor of 63 was obtained compared with the slope of the linear portion of the calibration curves before and after preconcentration. The calibration graph using the preconcentration system for cadmium was linear with a correlation coefficient of 0.9997, at levels from 1-40 ng/mL. The precision (RSD) for 11 replicate measurements were 3.2% for the determination of 5 ng/mL Cd(II) and 1.8% for 20 ng/mL Cd(II), respectively, and the detection limit (3s) was 0.36 ng/mL. The accuracy was assessed through the determination of a certified reference material, and also through recovery experiments. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  20. Instabilities and prediction of the acoustic resonance of flows with wall injection; Instabilites et prevision de l'accrochage acoustique des ecoulements avec injection parietale

    Energy Technology Data Exchange (ETDEWEB)

    Avalon, G. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), 91 - Palaiseau (France); Casalis, G. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), 91 - Palaiseau (France)

    1998-07-01

    Aero-acoustic coupling that occurs inside solid propellant rocket engines can lead to a longitudinal acoustic mode resonance of the combustion chamber. This phenomenon, which can have various origins, in analyzed using the Vecla test facility and the theory of linear stability of flows. Different comparisons between the hot-wire measurements performed and the theory of stability confirm the presence of intrinsic instabilities for this type of flow. The instability allows to selectively amplify a given range of frequencies which depends on the injection velocity and on the conduit height. The results obtained seem to indicate that when this frequency range does not comprise the longitudinal acoustic mode or the first harmonics, the flow becomes turbulent downstream. (J.S.)

  1. Speciation of mercury in fish samples by flow injection catalytic cold vapour atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yanlin [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Churchill, Victoria 3842 (Australia); Adeloju, Samuel B., E-mail: Sam.Adeloju@monash.edu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Churchill, Victoria 3842 (Australia)

    2012-04-06

    Highlights: Black-Right-Pointing-Pointer Successful speciation of inorganic and organic Hg with Fe{sup 3+}, Cu{sup 2+} and thiourea as catalysts. Black-Right-Pointing-Pointer Best sensitivity enhancement and similar sensitivity for MeHg and Hg{sup 2+} with Fe{sup 3+}. Black-Right-Pointing-Pointer Successful use of Hg{sup 2+} as the primary standard for quantification of inorganic and total-Hg. Black-Right-Pointing-Pointer Quantitative extraction of Hg and MeHg with 2 M HCl which contained thiourea. Black-Right-Pointing-Pointer Integration with FIA for rapid analysis with a sample throughput of 180 h{sup -1}. - Abstract: A rapid flow injection catalytic cold vapour atomic absorption spectrometric (FI-CCV-AAS) method is described for speciation and determination of mercury in biological samples. Varying concentrations of NaBH{sub 4} were employed for mercury vapour generation from inorganic and mixture of inorganic and organic (total) Hg. The presence of Fe{sup 3+}, Cu{sup 2+} and thiourea had catalytic effect on mercury vapour generation from methylmercury (MeHg) and, when together, Cu{sup 2+} and thiourea had synergistic catalytic effect on the vapour generation. Of the two metal ions, Fe{sup 3+} gave the best sensitivity enhancement, achieving the same sensitivity for MeHg and inorganic Hg{sup 2+}. Due to similarity of resulting sensitivity, Hg{sup 2+} was used successfully as a primary standard for quantification of inorganic and total Hg. The catalysis was homogeneous in nature, and it was assumed that the breaking of the C-Hg bond was facilitated by the delocalization of the 5d electron pairs in Hg atom. The extraction of MeHg and inorganic mercury (In-Hg) in fish samples were achieved quantitatively with hydrochloric acid in the presence of thiourea and determined by FI-CCV-AAS. The application of the method to the quantification of mercury species in a fish liver reference material DOLT-4 gave 91.5% and 102.3% recoveries for total and methyl mercury

  2. Flow-injection chemiluminescent determination of estrogen benzoate using the tris(1,10-phenanthroline) ruthenium(II)-permanganate system.

    Science.gov (United States)

    Ma, Yan; Cao, Wei; Qiao, Shuang; Liu, Wenwen; Yang, Jinghe

    2011-01-01

    Chemiluminescence (CL) detection for the determination of estrogen benzoate, using the reaction of tris(1,10-phenanthroline)ruthenium(II)-Na(2)SO(3)-permanganate, is described. This method is based on the CL reaction of estrogen benzoate (EB) with acidic potassium permanganate and tris(1,10-phenanthroline)ruthenium(II). The CL intensity is greatly enhanced when Na(2)SO(3) is added. After optimization of the different experimental parameters, a calibration graph for estrogen benzoate is linear in the range 0.05-10 µg/mL. The 3 s limit of detection is 0.024 µg/mL and the relative standard deviation was 1.3% for 1.0 µg/mL estrogen benzoate (n = 11). This proposed method was successfully applied to commercial injection samples and emulsion cosmetics. The mechanism of CL reaction was also studied. Copyright © 2011 John Wiley & Sons, Ltd.

  3. Simultaneous injection effective mixing flow analysis of urinary albumin using dye-binding reaction.

    Science.gov (United States)

    Ratanawimarnwong, Nuanlaor; Ponhong, Kraingkrai; Teshima, Norio; Nacapricha, Duangjai; Grudpan, Kate; Sakai, Tadao; Motomizu, Shoji

    2012-07-15

    A new four-channel simultaneous injection effective mixing flow analysis (SIEMA) system has been assembled for the determination of urinary albumin. The SIEMA system consisted of a syringe pump, two 5-way cross connectors, four holding coils, five 3-way solenoid valves, a 50-cm long mixing coil and a spectrophotometer. Tetrabromophenol blue anion (TBPB) in Triton X-100 micelle reacted with albumin at pH 3.2 to form a blue ion complex with a λ(max) 625nm. TBPB, Triton X-100, acetate buffer and albumin standard solutions were aspirated into four individual holding coils by a syringe pump and then the aspirated zones were simultaneously pushed in the reverse direction to the detector flow cell. Baseline drift, due to adsorption of TBPB-albumin complex on the wall of the hydrophobic PTFE tubing, was minimized by aspiration of Triton X-100 and acetate buffer solutions between samples. The calibration graph was linear in the range of 10-50μg/mL and the detection limit for albumin (3σ) was 0.53μg/mL. The RSD (n=11) at 30μg/mL was 1.35%. The sample throughput was 37/h. With a 10-fold dilution, interference from urine matrix was removed. The proposed method has advantages in terms of simple automation operation and short analysis time. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Study on effect of mixing mechanism by the transverse gaseous injection flow in scramjet engine with variable parameters

    Science.gov (United States)

    Yadav, Siddhita; Pandey, K. M.

    2018-04-01

    In scramjet engine the mixing mechanism of fuel and atmospheric air is very complicated, because the fuel have time in milliseconds for mixing with atmospheric air in combustion chamber having supersonic speed. Mixing efficiency of fuel and atmospheric air depends on mainly these parameters: Aspect ratio of injector, vibration amplitude, shock type, number of injector, jet to transverse flow momentum flux ratio, injector geometry, injection angle, molecular weight, incoming air stream angle, jet to transverse flow pressure ratio, spacing variation, mass flow rate of fuel etc. here is a very brief study of these parameters from previously done research on these parameters for the improvement of mixing efficiency. The mixing process have the significant role for the working of engine, and mixing between the atmospheric air and the jet fuel is significant factor for improving the overall thrust of the engine. The results obtained by study of papers are obtained by the 3D-Reynolds Average-Nervier-Stokes(RANS) equations along with the 2-equation k-ω shear-stress-transport (SST) turbulence model. Engine having multi air jets have 60% more mixing efficiency than single air jet, thus if the jets are increased, the mixing efficiency of engine can also be increased up to 150% by changing jet from 1 to 16. When using delta shape of injector the mixing efficiency is inversely proportional to the pressure ratio. When the fuel is injected inside the combustor from the top and bottom walls of the engine efficiency of mixing in reacting zone is higher than the single wall injection and in comparison to parallel flow, the transverse type flow is better as the atmospheric air jet can penetrate smoothly in the fuel jets and mixes well in less time. Hence this study of parameters and their effects on mixing can enhance the efficiency of mixing in engine.

  5. Sensitive determination of perphenazine in pharmaceuticals and human serum by flow injection chemiluminescence method using [Ru(phen)3]2+-Ce(IV) system and a chemometrical optimization approach

    International Nuclear Information System (INIS)

    Rezaei, B.; Mokhtari, A.

    2011-01-01

    This paper describes a simple, rapid and sensitive chemiluminescence (CL) method for the determination of perphenazine by flow injection system. All variables that can affect the CL response were optimized by employing central composite design (CCD) for the experimental design and response surface methodology for the modeling. Optimization by means of CCD method with respect to conventional single factor at a time method showed a significant improvement in the sensitivity. Under the optimum experimental conditions, a wide linear relationship between analyte concentration and peak height was obtained within the range 1.2-1,300 ng mL -1 with correlation coefficient of 0.9978. The limit of detection was 0.4 ng mL -1 (S/N = 3) and the relative standard deviation for 6 repeated measurements of a solution containing 70.5 ng mL -1 was lower than 4%. This method was successfully applied for the quantification of perphenazine in pharmaceutical formulations and human serum with good recoveries (95.3-104.0%). Sample throughput was 100 +- 5 samples per hour. (author)

  6. Preparation of Fe(3)O(4)@C@CNC multifunctional magnetic core/shell nanoparticles and their application in a signal-type flow-injection photoluminescence immunosensor.

    Science.gov (United States)

    Chu, Chengchao; Li, Meng; Li, Long; Ge, Shenguang; Ge, Lei; Yu, Jinghua; Yan, Mei; Song, Xianrang

    2013-11-01

    We describe here the preparation of carbon-coated Fe3O4 magnetic nanoparticles that were further fabricated into multifunctional core/shell nanoparticles (Fe3O4@C@CNCs) through a layer-by-layer self-assembly process of carbon nanocrystals (CNCs). The nanoparticles were applied in a photoluminescence (PL) immunosensor to detect the carcinoembryonic antigen (CEA), and CEA primary antibody was immobilized onto the surface of the nanoparticles. In addition, CEA secondary antibody and glucose oxidase were covalently bonded to silica nanoparticles. After stepwise immunoreactions, the immunoreagent was injected into the PL cell using a flow-injection PL system. When glucose was injected, hydrogen peroxide was obtained because of glucose oxidase catalysis and quenched the PL of the Fe3O4@C@CNC nanoparticles. The here proposed PL immunosensor allowed us to determine CEA concentrations in the 0.005–50 ng·mL-1 concentration range, with a detection limit of 1.8 pg·mL-1.

  7. Flow-injection amperometric determination of glucose using a biosensor based on immobilization of glucose oxidase onto Au seeds decorated on core Fe₃O₄ nanoparticles.

    Science.gov (United States)

    Samphao, Anchalee; Butmee, Preeyanut; Jitcharoen, Juthamas; Švorc, Ľubomír; Raber, Georg; Kalcher, Kurt

    2015-09-01

    An amperometric biosensor based on chemisorption of glucose oxidase (GOx) on Au seeds decorated on magnetic core Fe3O4 nanoparticles (Fe3O4@Au) and their immobilization on screen-printed carbon electrode bulk-modified with manganese oxide (SPCE{MnO2}) was designed for the determination of glucose. The Fe3O4@Au/GOx modified SPCE{MnO2} was used in a flow-injection analysis (FIA) arrangement. The experimental conditions were investigated in amperometric mode with the following optimized parameters: flow rate 1.7 mL min(-1), applied potential +0.38 V, phosphate buffer solution (PBS; 0.1 mol L(-1), pH 7.0) as carrier and 3.89 unit mm(-2) enzyme glucose oxidase loading on the active surface of the SPCE. The designed biosensor in FIA arrangement yielded a linear dynamic range for glucose from 0.2 to 9.0 mmol L(-1) with a sensitivity of 2.52 µA mM(-1) cm(-2), a detection limit of 0.1 mmol L(-1) and a quantification limit of 0.3 mmol L(-1). Moreover, a good repeatability of 2.8% (number of measurements n=10) and a sufficient reproducibility of 4.0% (number of sensors n=3) were achieved. It was found that the studied system Fe3O4@Au facilitated not only a simpler enzyme immobilization but also provided wider linear range. The practical application of the proposed biosensor for FIA quantification of glucose was tested in glucose sirup samples, honeys and energy drinks with the results in good accordance with those obtained by an optical glucose meter and with the contents declared by the producers. Copyright © 2015. Published by Elsevier B.V.

  8. Geological Factors Affecting Flow Spatial Continuity in Water Injection of Units Operating in the LGITJ–0102 Ore Body

    Directory of Open Access Journals (Sweden)

    Ilver M. Soto-Loaiza

    2016-05-01

    Full Text Available The objective of the investigation was to identify the geological factors affecting the spatial continuity of the flow during the process of flank water injection in the units operating in the Lower Lagunilla Hydrocarbon Ore Body. This included the evaluation of the recovery factor, the petro-physic properties such as porosity, permeability, water saturation and rock type and quality in each flow unit. it was observed that the rock type of the geologic structure in the ore body is variable. The lowest values for the petro-physic properties were found in the southern area while a high variability of these parameters was observed in the northern and central areas. It was concluded that the northern area has a great potential for the development of new injection projects for petroleum recovery.

  9. Thermodilution-determined Internal Jugular Venous Flow

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Widmer, Mario; Hilty, Matthias P

    2017-01-01

    PURPOSE: Cerebral blood flow (CBF) increases ~20% during whole body exercise although a Kety-Schmidt-determined CBF is reported to remain stable; a discrepancy that could reflect evaluation of arterial vs. internal jugular venous (IJV) flow and/or that CBF is influenced by posture. Here we test...

  10. Three-dimensional numerical simulation for plastic injection-compression molding

    Science.gov (United States)

    Zhang, Yun; Yu, Wenjie; Liang, Junjie; Lang, Jianlin; Li, Dequn

    2018-03-01

    Compared with conventional injection molding, injection-compression molding can mold optical parts with higher precision and lower flow residual stress. However, the melt flow process in a closed cavity becomes more complex because of the moving cavity boundary during compression and the nonlinear problems caused by non-Newtonian polymer melt. In this study, a 3D simulation method was developed for injection-compression molding. In this method, arbitrary Lagrangian- Eulerian was introduced to model the moving-boundary flow problem in the compression stage. The non-Newtonian characteristics and compressibility of the polymer melt were considered. The melt flow and pressure distribution in the cavity were investigated by using the proposed simulation method and compared with those of injection molding. Results reveal that the fountain flow effect becomes significant when the cavity thickness increases during compression. The back flow also plays an important role in the flow pattern and redistribution of cavity pressure. The discrepancy in pressures at different points along the flow path is complicated rather than monotonically decreased in injection molding.

  11. Impact of physical properties of biodiesel on the injection process in a common-rail direct injection system

    International Nuclear Information System (INIS)

    Boudy, Frederic; Seers, Patrice

    2009-01-01

    This paper presents the influence of biodiesel fuel properties on the injection mass flow rate of a diesel common-rail injection system. Simulations are first performed with ISO 4113 diesel fuel on a four-cylinder common-rail system to evaluate a single and triple injection strategies. For each injection strategy, the impact of modifying a single fuel property at a time is evaluated so as to quantify its influence on the injection process. The results show that fuel density is the main property that affects the injection process, such as total mass injected and pressure wave in the common-rail system. The fuel's viscosity and bulk modulus also influence, but to a lessen degree, the mass flow rate of the injector notably during multiple injection strategies as individual properties change the fuel's dampening property and friction coefficient.

  12. Magnetic detection of ferrofluid injection zones

    Energy Technology Data Exchange (ETDEWEB)

    Borglin, S.; Moridis, G.; Becker, A.

    1998-03-01

    Ferrofluids are stable colloidal suspensions of magnetic particles that can be stabilized in various carrier liquids. In this study the authors investigate the potential of ferrofluids to trace the movement and position of liquids injected in the subsurface using geophysical methods. An ability to track and monitor the movement and position of injected liquids is essential in assessing the effectiveness of the delivery system and the success of the process. Ferrofluids can also provide a significant detection and verification tool in containment technologies, where they can be injected with the barrier liquids to provide a strong signature allowing determination of the barrier geometry, extent, continuity and integrity. Finally, ferrofluids may have unique properties as tracers for detecting preferential flow features (such as fractures) in the subsurface, and thus allow the design of more effective remediation systems. In this report the authors review the results of the investigation of the potential of ferrofluids to trace the movement and position of liquids injected in the subsurface using geophysical methods. They demonstrate the feasibility of using conventional magnetometry for detecting subsurface zones of injected ferrofluids used to trace liquids injected for remediation or barrier formation. The geometrical shapes considered were a sphere, a thin disk, a rectangular horizontal slab, and a cylinder. Simple calculations based on the principles of magnetometry are made to determine the detection depths of FTs. Experiments involving spherical, cylindrical and horizontal slabs show a very good agreement between predictions and measurements.

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

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Ganjali

    2013-07-01

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

  14. Effect of cross-flow direction of coolant on film cooling effectiveness with one inlet and double outlet hole injection

    Directory of Open Access Journals (Sweden)

    Guangchao Li

    2012-12-01

    Full Text Available In order to study the effect of cross-flow directions of an internal coolant on film cooling performance, the discharge coefficients and film cooling effectiveness with one inlet and double outlet hole injections were simulated. The numerical results show that two different cross-flow directions of the coolant cause the same decrease in the discharge coefficients as that in the case of supplying coolant by a plenum. The different proportion of the mass flow out of the two outlets of the film hole results in different values of the film cooling effectiveness for three different cases of coolant supplies. The film cooling effectiveness is the highest for the case of supplying coolant by the plenum. At a lower blowing ratio of 1.0, the film cooling effectiveness with coolant injection from the right entrance of the passage is higher than that from the left entrance of the passage. At a higher blowing ratio of 2.0, the opposite result is found.

  15. Load Flow Analysis of a 15Mva Injection Substation | Oshevire ...

    African Journals Online (AJOL)

    This load flow helps to determine the state of the power system for a given load and generation distribution. This paper presents the computer aided power flow analysis of the existing Otovwodo33/11kV distribution network using the ETAP 7.0 software. The result showed that out of 91load feeders of which 6 is out of service, ...

  16. Regulation of pulpal blood flow

    International Nuclear Information System (INIS)

    Kim, S.

    1985-01-01

    The regulation of blood flow of the dental pulp was investigated in dogs and rats anesthetized with sodium pentobarbital. Pulpal blood flow was altered by variations of local and systemic hemodynamics. Macrocirculatory blood flow (ml/min/100 g) in the dental pulp was measured with both the 133 Xe washout and the 15-microns radioisotope-labeled microsphere injection methods on the canine teeth of dogs, to provide a comparison of the two methods in the same tooth. Microcirculatory studies were conducted in the rat incisor tooth with microscopic determination of the vascular pattern, RBC velocity, and intravascular volumetric flow distribution. Pulpal resistance vessels have alpha- and beta-adrenergic receptors. Activation of alpha-receptors by intra-arterial injection of norepinephrine (NE) caused both a reduction in macrocirculatory Qp in dogs and decreases in arteriolar and venular diameters and intravascular volumetric flow (Qi) in rats. These responses were blocked by the alpha-antagonist PBZ. Activation of beta-receptors by intra-arterial injection of isoproterenal (ISO) caused a paradoxical reduction of Qp in dogs. In rats, ISO caused a transient increase in arteriolar Qi followed by a flow reduction; arteriolar dilation was accompanied by venular constriction. These macrocirculatory and microcirculatory responses to ISO were blocked by the alpha-antagonist propranolol

  17. Flow-based determination of methionine in pharmaceutical formulations exploiting TGA-capped CdTe quantum dots for enhancing the luminol-KIO{sub 4} chemiluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Min, E-mail: mzhou8367@sina.com [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Wang, Ailian [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Jiuquan Enviromental Protection Bureau, Jiuquan 735000 (China); Li, Cong; Luo, Xiaowei; Ma, Yongjun [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2017-03-15

    A novel flow-injection chemiluminescence method (FI-CL) was established for the determination of methionine in this paper, based on its strong enhancement on CL intensity of the luminol-KIO{sub 4} system catalyzed by thioglycolic acid-capped CdTe quantum dots in alkaline media. Under the optimized conditions, the relative CL intensity was in proportion to methionine concentration in the range from 1.0×10{sup −8} to 1.0×10{sup −5} g mL{sup −1} with a detection limit of 6.6×10{sup −9} g mL{sup −1} (3σ). The relative standard deviation (RSD) of the CL intensity for 1.0×10{sup −6} g mL{sup −1} standard methionine solution was 0.97% (n=11). The proposed method was successfully applied to determine methionine in commercial pharmaceutical formulations with recoveries between 98.0% and 101.9%. The possible CL mechanism was discussed as well. - Graphical abstract: Methionine in commercial pharmaceutical formulations was determined by flow-injection chemiluminescence and the possible chemiluminescence mechanism was discussed as well.

  18. Image resolution influence on determination of resin injection rock mass

    Science.gov (United States)

    Wang, Weixing; Hakami, Eva

    2006-01-01

    In the context of nuclear waste repositories, an important approach to understanding brittle rock mass behavior to integrate new and powerful observational and numerical methods with multi-functional 3-D imaging and visualization techniques. Since 1994, Swedish Nuclear Fuel and Waste Management Company (SKB) have identified the need for a better understanding of radionuclide transport and retention processes in fractured rock. As a cooperation project between Sweden and China, we sampled a number of rock specimens for analyze rock fracture network by optical image technique. The samples are resin injected, in which way; opened fractures can be seen clearly by means of UV (Ultraviolet) light illumination. In the study period, we used different optical focuses to obtain the images from the same samples; we found that Image resolution influences on porosity determination of resin injected rock mass. This paper presents and discusses the six issues based on our research results: (1) Fracture porosity increases as camera focus distance decreases; (2) Porosity increases as illumination increases in resin injected fracture images; (3) To roughly estimate the porosity, the low resolution image can be used; (4) To collect more details of fracture information, the high resolution image is needed; (5) The resolution of image should be determined based on the aim of fracture analysis; (6) To acquire high resolution image, constructing a special illumination (standard) box maybe helpful to avoid light reflection and diffusion.

  19. On-line sample-pre-treatment schemes for trace-level determinations of metals by coupling flow injection or sequential injection with ICP-MS

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2003-01-01

    a polytetrafluoroethylene (PTFE) knotted reactor (KR), solvent extraction-back extraction and hydride/vapor generation. It also addresses a novel, robust approach, whereby the protocol of SI-LOV-bead injection (BI) on-line separation and pre-concentration of ultra-trace levels of metals by a renewable microcolumn...

  20. Sub-1min separation in sequential injection chromatography for determination of synthetic water-soluble dyes in pharmaceutical formulation.

    Science.gov (United States)

    Davletbaeva, Polina; Chocholouš, Petr; Bulatov, Andrey; Šatínský, Dalibor; Solich, Petr

    2017-09-05

    Sequential Injection Chromatography (SIC) evolved from fast and automated non-separation Sequential Injection Analysis (SIA) into chromatographic separation method for multi-element analysis. However, the speed of the measurement (sample throughput) is due to chromatography significantly reduced. In this paper, a sub-1min separation using medium polar cyano monolithic column (5mm×4.6mm) resulted in fast and green separation with sample throughput comparable with non-separation flow methods The separation of three synthetic water-soluble dyes (sunset yellow FCF, carmoisine and green S) was in a gradient elution mode (0.02% ammonium acetate, pH 6.7 - water) with flow rate of 3.0mLmin -1 corresponding with sample throughput of 30h -1 . Spectrophotometric detection wavelengths were set to 480, 516 and 630nm and 10Hz data collection rate. The performance of the separation was described and discussed (peak capacities 3.48-7.67, peak symmetries 1.72-1.84 and resolutions 1.42-1.88). The method was represented by validation parameters: LODs of 0.15-0.35mgL -1 , LOQs of 0.50-1.25mgL -1 , calibration ranges 0.50-150.00mgL -1 (r>0.998) and repeatability at 10.0mgL -1 of RSD≤0.98% (n=6). The method was used for determination of the dyes in "forest berries" colored pharmaceutical cough-cold formulation. The sample matrix - pharmaceuticals and excipients were not interfering with vis determination because of no retention in the separation column and colorless nature. The results proved the concept of fast and green chromatography approach using very short medium polar monolithic column in SIC. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Sequential injection spectrophotometric determination of V(V) in ...

    African Journals Online (AJOL)

    2009-01-15

    Jan 15, 2009 ... The determination was based on the oxidation of dopamine (DP) by V(V) in acidic medium followed by ... To overcome some of these drawbacks some flow injec- ..... The analytical signal increased with the reactor length.

  2. Vacuum injection system for hydrogen micro-spheres in the CELSIUS storage ring

    International Nuclear Information System (INIS)

    Tinoco, Hernan.

    1990-01-01

    The use of hydrogen micro-spheres as internal targets in the CELSIUS storage ring has been proposed for light meson rare decay measurements. The target generation apparatus design is based on that developed for refueling of fusion tokamak reactors. The micro-spheres are produced by acoustic excitation of a liquid hydrogen jet, and are injected into vacuum for the experiments by means of a hydrogen gas flow through an injection nozzle. The work reported here is an analysis of the gas flow in the injection nozzle, of the entrained motion of the micro-spheres considered as spherical particles, and of the heat transfer between them and the gas. The computation of the heat transfer allows the determination of the conditions under which the evaporation of the micro-spheres is negligible. It is shown that the gas must be cooled to temperatures near that of the micro-spheres for these to survive. Together with the computation of the gas flow and particle motion, the analysis includes the design of the injection nozzle. The requirements of well defined mass flow rate and low perturbation level suggest a nozzle consisting of a contraction region and a straight region with constant cross-sectional area. This nozzle is to be operated with stagnation conditions near the triple point conditions and choked flow at the exit. The condition of a limiting mass flow rate of the order of 10 -6 kg/s together with the operating conditions bound the exit diameter to values of 200-250 μm. Other geometrical parameters have only a subordinate importance on the injection nozzle design

  3. Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase.

    Science.gov (United States)

    Rahimi, Masoud; Shahhosseini, Shahrokh; Movahedirad, Salman

    2017-11-01

    A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Injection practices in a metropolis of North India: perceptions, determinants and issues of safety.

    Science.gov (United States)

    Kotwal, A; Priya, R; Thakur, R; Gupta, V; Kotwal, J; Seth, T

    2004-08-01

    At least 50 percent of the injections administered each year are unsafe, more particularly in developing countries, posing serious health risks. An initial assessment to describe injection practices; their determinants and adverse effects can prevent injection-associated transmission of blood borne pathogens by reducing injection frequency and adoption of safe injection practices. To assess the injection practices in a large metropolitan city encompassing varied socio-cultural scenarios. STUDY SETTING AND DESIGN: Field based cross sectional survey covering urban non-slum, slum and peri-urban areas of a large metropolitan city. Injection prescribers, providers and community members selected by random sampling from the study areas. Pre tested questionnaires assessed knowledge and perceptions of study subjects towards injections and their possible complications. Observation of the process of injection and prescription audit also carried out. MS Access for database and SPSS ver 11 for analysis. Point estimates, 95% confidence intervals, Chi Square, t test, one-way ANOVA. The per capita injection rate was 5.1 per year and ratio of therapeutic to immunization injections was 4.4:1. Only 22.5%of injections were administered with a sterile syringe and needle. The level of knowledge about HIV and HBV transmission by unsafe injections was satisfactory amongst prescribers and community, but inadequate amongst providers. HCV was known to a very few in all the groups. The annual incidence of needle stick injuries among providers was quite high. A locally relevant safe injection policy based on multi disciplinary approach is required to reduce number of injections, unsafe injections and their attendant complications.

  5. Developments in Pulsed Neutron Activation for Determination of Water Flow in Pipes

    Energy Technology Data Exchange (ETDEWEB)

    Mattsson, Haakan

    2003-06-01

    In PNA (pulsed neutron activation) it is important that the measured data can be related to the total mass flow. In this thesis two fundamental problems of the measurement technique and data treatment have been investigated: transport/mixing and background radiation. The principle of PNA is to introduce a radioactive substance into a pipe by bombarding fluid in the pipe with neutron pulses. The fluid in the pipe is activated and subsequently transported and mixed with the flow. Gamma radiation emitted from the activity is measured with one or two detectors downstream from the activation point. The time-resolved signal from the detectors is used to calculate the average velocity of the water flow. Due to the short distance between the neutron generator and the pipe the activity in the pipe becomes highly inhomogeneous. The transport and mixing of the activity were simulated using colour which was injected into the flow. It was found that the inhomogeneous activity distribution must be taken into account if the precision of the measurements is to be improved. The shape of the background in PNA affects the shape and position of the time spectrum. The nature of the background has been determined using one detector upstream and one downstream of the neutron generator. The background was shown to be caused by {sup 16}N. A method that subtracts the background from the PNA time spectrum was also developed.

  6. Developments in Pulsed Neutron Activation for Determination of Water Flow in Pipes

    International Nuclear Information System (INIS)

    Mattsson, Haakan

    2003-06-01

    In PNA (pulsed neutron activation) it is important that the measured data can be related to the total mass flow. In this thesis two fundamental problems of the measurement technique and data treatment have been investigated: transport/mixing and background radiation. The principle of PNA is to introduce a radioactive substance into a pipe by bombarding fluid in the pipe with neutron pulses. The fluid in the pipe is activated and subsequently transported and mixed with the flow. Gamma radiation emitted from the activity is measured with one or two detectors downstream from the activation point. The time-resolved signal from the detectors is used to calculate the average velocity of the water flow. Due to the short distance between the neutron generator and the pipe the activity in the pipe becomes highly inhomogeneous. The transport and mixing of the activity were simulated using colour which was injected into the flow. It was found that the inhomogeneous activity distribution must be taken into account if the precision of the measurements is to be improved. The shape of the background in PNA affects the shape and position of the time spectrum. The nature of the background has been determined using one detector upstream and one downstream of the neutron generator. The background was shown to be caused by 16 N. A method that subtracts the background from the PNA time spectrum was also developed

  7. Clinical studies on the lymph flow of the esophagus by injecting sup(99m)Tc-rhenium colloid into the esophageal wall

    International Nuclear Information System (INIS)

    Baba, Masamichi; Tanabe, Gen; Nishi, Mitsumasa

    1985-01-01

    Using 29 operative cases lymph flow of the esophagus was investigated by injecting endoscopically sup(99m)Tc-Rhenium colloid. Rhenium colloid lymphoscintigraphy was made, and 30 -- 32 hours after injection RI up take (cpm/g) of resected lymph nodes was counted by scintillation counter. 1. RI up take of resected lymph nodes correspond with the lymphoscintigraphy of resected lymph nodes therefore, RI up take count was available to study the extra-mural lymph flow of the esophagus. 2. In the cases injected at upper part of the esophagus, the high counted RI up take was noted in bifurcation lymph nodes, upper mediastinal lymph nodes and bilateral supraclavicular lymph nodes. In the cases injected at middle part of the esophagus, bilateral supraclavicular lymph nodes, upper mediastinal lymph nodes and left gastric artery lymph nodes revealed the high RI up takes. In the cases injected at lower part of the esophagus, RI up take was highly noted in bifurcation lymph nodes, left gastric artery lymph nodes and celiac axis lymph nodes. In the cases injected at esophago-gastric junction, the high counted RI up take was noted in left gastric artery lymph nodes, celiac axis lymph nodes and the lymph nodes around the left renal vein. 3. In the cases injected at upper, middle parts of the esophagus, bilateral supraclavicular lymph nodes revealed the high RI up take. Some of these lymph nodes are regarded as directly connected with the extra-mural lymph vessls of the esophagus. Therefore, it was suggested that existence of ''direct lymph flow'' from which upper, middle intrathoracic esophagus directly connected to right supraclavicular lymph nodes. 4. It is important to perform bilateral modified neck dissection in case of upper, middle intrathoracic esophageal cancer and is important to dissect the lymph nodes around the left renal vein in case of esophago-gastric cancer and lower intrathoracic esophageal cancer. (J.P.N.)

  8. Experimental Investigation of Diffuser Hub Injection to Improve Centrifugal Compressor Stability

    Science.gov (United States)

    Skoch, Gary J.

    2004-01-01

    Results from a series of experiments to investigate whether centrifugal compressor stability could be improved by injecting air through the diffuser hub surface are reported. The research was conducted in a 4:1 pressure ratio centrifugal compressor configured with a vane-island diffuser. Injector nozzles were located just upstream of the leading edge of the diffuser vanes. Nozzle orientations were set to produce injected streams angled at 8, 0 and +8 degrees relative to the vane mean camber line. Several injection flow rates were tested using both an external air supply and recirculation from the diffuser exit. Compressor flow range did not improve at any injection flow rate that was tested. Compressor flow range did improve slightly at zero injection due to the flow resistance created by injector openings on the hub surface. Leading edge loading and semi-vaneless space diffusion showed trends similar to those reported earlier from shroud surface experiments that did improve compressor flow range. Opposite trends are seen for hub injection cases where compressor flow range decreased. The hub injection data further explain the range improvement provided by shroud-side injection and suggest that different hub-side techniques may produce range improvement in centrifugal compressors.

  9. Development of a Sequential Injection Analysis System for the Determination of Saccharin.

    Science.gov (United States)

    Wibowotomo, Budi; Eun, Jong-Bang; Rhee, Jong Il

    2017-12-12

    Saccharin is a powerfully sweet nonnutritive sweetener that has been approved for food-processing applications within the range of 100-1200 mg/kg. A simple, rapid, and cost-effective sequential injection analysis (SIA) technique was developed to determine the saccharin level. This method is based on the reaction of saccharin with p-chloranil in an ethanol medium with a hydrogen peroxide (H₂O₂) acceleration, and the resultant violet-red compound was detected using a UV-Vis spectrophotometer at λ max = 420 nm. To ascertain the optimal conditions for the SIA system, several parameters were investigated, including buffer flow rate and volume, p-chloranil concentration, and reactant volumes (saccharin, p-chloranil, and H₂O₂). The optimum setup of the SIA system was achieved with a buffer flow rate, buffer volume, and draw-up time of 1.2 mL/min, 2900 µL, and ~145 s, respectively. The optimal p-chloranil concentration is 30 mM, and the best reactant volumes, presented in an ordered sequence, are as follows: 30 µL of H₂O₂, 450 µL of saccharin, and 150 µL of p-chloranil. The optimized SIA configuration produced a good linear calibration curve with a correlation coefficient (R² = 0.9812) in the concentration range of 20-140 mg/L and with a detection limit of 19.69 mg/L. Analytical applications in different food categories also showed acceptable recovery values in the range of 93.1-111.5%. This simple and rapid SIA system offers great feasibility for the saccharin quality control in food-product processing.

  10. Reverse-Tangent Injection in a Centrifugal Compressor

    Science.gov (United States)

    Skoch, Gary J.

    2007-01-01

    Injection of working fluid into a centrifugal compressor in the reverse tangent direction has been invented as a way of preventing flow instabilities (stall and surge) or restoring stability when stall or surge has already commenced. The invention applies, in particular, to a centrifugal compressor, the diffuser of which contains vanes that divide the flow into channels oriented partly radially and partly tangentially. In reverse-tangent injection, a stream or jet of the working fluid (the fluid that is compressed) is injected into the vaneless annular region between the blades of the impeller and the vanes of the diffuser. As used here, "reverse" signifies that the injected flow opposes (and thereby reduces) the tangential component of the velocity of the impeller discharge. At the same time, the injected jet acts to increase the radial component of the velocity of the impeller discharge.

  11. Noninvasive measurement of an index of renal blood flow

    International Nuclear Information System (INIS)

    Powers, T.A.; Rees, R.S.; Bowen, R.D.

    1983-01-01

    A new technique for the noninvasive measurement of an index of renal blood flow is described. The method utilizes ultrasound determined renal volume and radionuclide assessment of the mean transit time of a pertechnetate bolus through the kidneys. From this information a value for flow is calculated according to compartmental analysis principles. There is good correlation between renal blood flow estimated by this technique and that determined by microsphere injection

  12. Effect of Process Parameters on Flow Length and Flash Formation in Injection Moulding of High Aspect Ratio Polymeric Micro Features

    Directory of Open Access Journals (Sweden)

    Abdelkhalik Eladl

    2018-01-01

    Full Text Available This paper reports an investigation of the effects of process parameters on the quality characteristics of polymeric parts produced by micro injection moulding (μIM with two different materials. Four injection moulding process parameters (injection velocity, holding pressure, melt temperature and mould temperature were investigated using Polypropylene (PP and Acrylonitrile Butadiene Styrene (ABS. Three key characteristics of the mouldings were evaluated with respect to process settings and the material employed: part mass, flow length and flash formation. The experimentation employs a test part with four micro fingers with different aspect ratios (from 21 up to 150 and was carried out according to the Design of Experiments (DOE statistical technique. The results show that holding pressure and injection velocity are the most influential parameters on part mass with a direct effect for both materials. Both parameters have a similar effect on flow length for both PP and ABS at all aspect ratios and have higher effects as the feature thickness decreased below 300 μm. The study shows that for the investigated materials the injection speed and packing pressure were the most influential parameters for increasing the amount of flash formation, with relative effects consistent for both materials. Higher melt and mould temperatures settings were less influential parameters for increasing the flash amount when moulding with both materials. Of the two investigated materials, PP was the one exhibiting more flash formation as compared with ABS, when corresponding injection moulding parameters settings for both materials were considered.

  13. Radial lean direct injection burner

    Science.gov (United States)

    Khan, Abdul Rafey; Kraemer, Gilbert Otto; Stevenson, Christian Xavier

    2012-09-04

    A burner for use in a gas turbine engine includes a burner tube having an inlet end and an outlet end; a plurality of air passages extending axially in the burner tube configured to convey air flows from the inlet end to the outlet end; a plurality of fuel passages extending axially along the burner tube and spaced around the plurality of air passage configured to convey fuel from the inlet end to the outlet end; and a radial air swirler provided at the outlet end configured to direct the air flows radially toward the outlet end and impart swirl to the air flows. The radial air swirler includes a plurality of vanes to direct and swirl the air flows and an end plate. The end plate includes a plurality of fuel injection holes to inject the fuel radially into the swirling air flows. A method of mixing air and fuel in a burner of a gas turbine is also provided. The burner includes a burner tube including an inlet end, an outlet end, a plurality of axial air passages, and a plurality of axial fuel passages. The method includes introducing an air flow into the air passages at the inlet end; introducing a fuel into fuel passages; swirling the air flow at the outlet end; and radially injecting the fuel into the swirling air flow.

  14. Numerical Simulations of Two-Phase Reacting Flow in a Single-Element Lean Direct Injection (LDI) Combustor Using NCC

    Science.gov (United States)

    Liu, Nan-Suey; Shih, Tsan-Hsing; Wey, C. Thomas

    2011-01-01

    A series of numerical simulations of Jet-A spray reacting flow in a single-element lean direct injection (LDI) combustor have been conducted by using the National Combustion Code (NCC). The simulations have been carried out using the time filtered Navier-Stokes (TFNS) approach ranging from the steady Reynolds-averaged Navier-Stokes (RANS), unsteady RANS (URANS), to the dynamic flow structure simulation (DFS). The sub-grid model employed for turbulent mixing and combustion includes the well-mixed model, the linear eddy mixing (LEM) model, and the filtered mass density function (FDF/PDF) model. The starting condition of the injected liquid spray is specified via empirical droplet size correlation, and a five-species single-step global reduced mechanism is employed for fuel chemistry. All the calculations use the same grid whose resolution is of the RANS type. Comparisons of results from various models are presented.

  15. Analytical and numerical solution of three-dimensional channel flow in presence of a sinusoidal fluid injection and a chemical reaction

    Directory of Open Access Journals (Sweden)

    Sahin Ahmed

    2015-06-01

    Full Text Available Modeling of three-dimensional channel flow in a chemically-reacting fluid between two long vertical parallel flat plates in the presence of a transverse magnetic field is presented. The stationary plate is subjected to a transverse sinusoidal injection velocity distribution while the uniformly moving plate is subjected to a constant suction and slip boundary conditions. Due to this type of injection velocity, the flow becomes three dimensional. Comparisons with previously published work are performed and the results are found to be in excellent agreement. An increase in the permeability/magnetic parameter is found to escalate the velocity near the plate in motion. Growing Reynolds number or magnetic parameter enhances the x-component and reduces the z-component of the skin-friction at the wall at rest. The acquired knowledge in our study can be used by designers to control MHD flow as suitable for certain applications which include laminar magneto-aerodynamics, materials processing and MHD propulsion thermo-fluid dynamics.

  16. Development of a sequential injection-square wave voltammetry method for determination of paraquat in water samples employing the hanging mercury drop electrode.

    Science.gov (United States)

    dos Santos, Luciana B O; Infante, Carlos M C; Masini, Jorge C

    2010-03-01

    This work describes the development and optimization of a sequential injection method to automate the determination of paraquat by square-wave voltammetry employing a hanging mercury drop electrode. Automation by sequential injection enhanced the sampling throughput, improving the sensitivity and precision of the measurements as a consequence of the highly reproducible and efficient conditions of mass transport of the analyte toward the electrode surface. For instance, 212 analyses can be made per hour if the sample/standard solution is prepared off-line and the sequential injection system is used just to inject the solution towards the flow cell. In-line sample conditioning reduces the sampling frequency to 44 h(-1). Experiments were performed in 0.10 M NaCl, which was the carrier solution, using a frequency of 200 Hz, a pulse height of 25 mV, a potential step of 2 mV, and a flow rate of 100 µL s(-1). For a concentration range between 0.010 and 0.25 mg L(-1), the current (i(p), µA) read at the potential corresponding to the peak maximum fitted the following linear equation with the paraquat concentration (mg L(-1)): i(p) = (-20.5 ± 0.3)C (paraquat) - (0.02 ± 0.03). The limits of detection and quantification were 2.0 and 7.0 µg L(-1), respectively. The accuracy of the method was evaluated by recovery studies using spiked water samples that were also analyzed by molecular absorption spectrophotometry after reduction of paraquat with sodium dithionite in an alkaline medium. No evidence of statistically significant differences between the two methods was observed at the 95% confidence level.

  17. Reduction of Altitude Diffuser Jet Noise Using Water Injection

    Science.gov (United States)

    Allgood, Daniel C.; Saunders, Grady P.; Langford, Lester A.

    2011-01-01

    A feasibility study on the effects of injecting water into the exhaust plume of an altitude rocket diffuser for the purpose of reducing the far-field acoustic noise has been performed. Water injection design parameters such as axial placement, angle of injection, diameter of injectors, and mass flow rate of water have been systematically varied during the operation of a subscale altitude test facility. The changes in acoustic far-field noise were measured with an array of free-field microphones in order to quantify the effects of the water injection on overall sound pressure level spectra and directivity. The results showed significant reductions in noise levels were possible with optimum conditions corresponding to water injection at or just upstream of the exit plane of the diffuser. Increasing the angle and mass flow rate of water injection also showed improvements in noise reduction. However, a limit on the maximum water flow rate existed as too large of flow rate could result in un-starting the supersonic diffuser.

  18. Multi-Phase Modeling of Rainbird Water Injection

    Science.gov (United States)

    Vu, Bruce T.; Moss, Nicholas; Sampson, Zoe

    2014-01-01

    This paper describes the use of a Volume of Fluid (VOF) multiphase model to simulate the water injected from a rainbird nozzle used in the sound suppression system during launch. The simulations help determine the projectile motion for different water flow rates employed at the pad, as it is critical to know if water will splash on the first-stage rocket engine during liftoff.

  19. Determination of trace thorium in water samples by flow injection fluorescence spectrophotometry with microcolumn on-line preconcentration

    International Nuclear Information System (INIS)

    Shen Zhuqin; Zhang Yanan; Guo Dongfa; Huang Yun

    1991-01-01

    An on-line preconcentration time resolved fluorimetric method was developed for the determination of trace thorium in water, based on luminescence of complex Th-morin-TOPO (or TRPO)-sodium lauryl sulfate in sulfuric acid medium. Interferences from companied cations, such as Al 3+ and Zr 4+ , which emit fluorescence with much slower rising rate at the same condition were effectively eliminated through optimization of the manifold parameters and precisely controlling of the elution flow rate. Effects of nearly 40 ions were also investigated. The detection limit, the liner range and relative standard deviation for 50 ng Th are 2.5 ng/L, 0∼80 ng and 3.6%, respectively. Sampling rate is 30 per hour

  20. Imaging diagnostics of ethanol port fuel injection sprays for automobile engine applications

    International Nuclear Information System (INIS)

    Padala, Srinivas; Le, Minh Khoi; Kook, Sanghoon; Hawkes, Evatt R.

    2013-01-01

    This paper presents characteristics of ethanol sprays at port fuel injection (PFI) conditions with variations in injection and ambient parameters. Details of temporal and spatial development of ethanol PFI sprays are studied using Mie-scattering and high-speed shadowgraph imaging techniques. Momentum flux-based injection rate measurement is also performed. The influences of fuel flow-rate, injection duration, and ambient air cross-flow are of particular interest in an effort to understand ethanol PFI spray characteristics that are relevant to automobile engines. For comparison purposes, the results from gasoline fuel are also presented. Ethanol flow-rate effects are studied using two injectors with different nozzle-hole sizes at a fixed injection pressure. From the experiments, it was found that the actual injection duration was longer for the higher flow-rate injector although an electronic pulse width was fixed. This was due to an extended delay in the injector needle closing as the flow resistance against the needle was increased for the high flow-rate injector. For liquid droplets, the larger hole size of the higher flow-rate injector caused a higher mean droplet diameter and higher number of droplets. Injection duration was also varied to study transient spray behaviour: short-injection sprays with the end-of-injection transient dominating the overall spray development were compared to long, steady-injection sprays. From Mie-scattering images, the number of droplets and mean droplet diameter were found to be less for the short injection sprays. Detailed analysis using an axial profile of the number of droplets and mean droplet diameter suggested that the observed trends were a result of increased evaporation rate near the nozzle after the end of injection. This was consistent with shadowgraph images showing no liquid regions but only the vapour-phase fuel near the nozzle. Under the influence of ambient air cross-flow, both mean droplet diameter and number of

  1. Optimum design of the injection duct system of a stenter machine

    Energy Technology Data Exchange (ETDEWEB)

    Juraeva, Makhsuda; Song, Dong Joo [Yeungnam University, Geyongsan (Korea, Republic of); Ryu, Kyung Jin [Ajou Motor College, Boryeong (Korea, Republic of)

    2017-05-15

    Stenter machines are used for drying fabrics in the textile industry and have a heater, injection duct system, and fans inside a chamber. The injection duct system has ducts and air-injecting holes. Plane-type injection duct systems were investigated to obtain uniform airflow at the air-injecting holes. The flow field of the injection duct systems was computed using ANSYS CFX with different heights of the duct end and different shapes for the air-injecting holes. There was a high mass flow rate at the air-injecting holes and high airflow circulation inside both plane-type and mountain-type ducts at the ends. The height of the duct end was varied between 40 mm and 160 mm. The injection duct systems were analyzed with four different shapes of air-injecting holes. The circular and elliptical holes had lower standard deviations of the mass flow rate than other shapes. Relatively uniform mass flow rates were obtained in the plane-type and mountain-type duct systems when the height of the duct end was 40 mm and the shape of the air-injecting holes was circular or elliptical. The developed injection duct systems were improved by obtaining a uniform mass flow rate at the air-injecting holes. A stenter prototype was fabricated with the developed injection duct system to confirm the numerical results. The developed injection duct system had better performance than the original system.

  2. Application of a novel metabolomic approach based on atmospheric pressure photoionization mass spectrometry using flow injection analysis for the study of Alzheimer's disease.

    Science.gov (United States)

    González-Domínguez, Raúl; García-Barrera, Tamara; Gómez-Ariza, José Luis

    2015-01-01

    The use of atmospheric pressure photoionization is not widespread in metabolomics, despite its considerable potential for the simultaneous analysis of compounds with diverse polarities. This work considers the development of a novel analytical approach based on flow injection analysis and atmospheric pressure photoionization mass spectrometry for rapid metabolic screening of serum samples. Several experimental parameters were optimized, such as type of dopant, flow injection solvent, and their flows, given that a careful selection of these variables is mandatory for a comprehensive analysis of metabolites. Toluene and methanol were the most suitable dopant and flow injection solvent, respectively. Moreover, analysis in negative mode required higher solvent and dopant flows (100 µl min(-1) and 40 µl min(-1), respectively) compared to positive mode (50 µl min(-1) and 20 µl min(-1)). Then, the optimized approach was used to elucidate metabolic alterations associated with Alzheimer's disease. Thereby, results confirm the increase of diacylglycerols, ceramides, ceramide-1-phosphate and free fatty acids, indicating membrane destabilization processes, and reduction of fatty acid amides and several neurotransmitters related to impairments in neuronal transmission, among others. Therefore, it could be concluded that this metabolomic tool presents a great potential for analysis of biological samples, considering its high-throughput screening capability, fast analysis and comprehensive metabolite coverage. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Sensitive determination of perphenazine in pharmaceuticals and human serum by flow injection chemiluminescence method using [Ru(phen){sub 3}]{sup 2+}-Ce(IV) system and a chemometrical optimization approach

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, B.; Mokhtari, A., E-mail: rezaei@cc.iut.ac.i [Isfahan University of Technology (Iran, Islamic Republic of). Dept. of Chemistry

    2011-07-01

    This paper describes a simple, rapid and sensitive chemiluminescence (CL) method for the determination of perphenazine by flow injection system. All variables that can affect the CL response were optimized by employing central composite design (CCD) for the experimental design and response surface methodology for the modeling. Optimization by means of CCD method with respect to conventional single factor at a time method showed a significant improvement in the sensitivity. Under the optimum experimental conditions, a wide linear relationship between analyte concentration and peak height was obtained within the range 1.2-1,300 ng mL{sup -1} with correlation coefficient of 0.9978. The limit of detection was 0.4 ng mL{sup -1} (S/N = 3) and the relative standard deviation for 6 repeated measurements of a solution containing 70.5 ng mL{sup -1} was lower than 4%. This method was successfully applied for the quantification of perphenazine in pharmaceutical formulations and human serum with good recoveries (95.3-104.0%). Sample throughput was 100 +- 5 samples per hour. (author)

  4. Iodine speciation in coastal and inland bathing waters and seaweeds extracts using a sequential injection standard addition flow-batch method.

    Science.gov (United States)

    Santos, Inês C; Mesquita, Raquel B R; Bordalo, Adriano A; Rangel, António O S S

    2015-02-01

    The present work describes the development of a sequential injection standard addition method for iodine speciation in bathing waters and seaweeds extracts without prior sample treatment. Iodine speciation was obtained by assessing the iodide and iodate content, the two inorganic forms of iodine in waters. For the determination of iodide, an iodide ion selective electrode (ISE) was used. The indirect determination of iodate was based on the spectrophotometric determination of nitrite (Griess reaction). For the iodate measurement, a mixing chamber was employed (flow batch approach) to explore the inherent efficient mixing, essential for the indirect determination of iodate. The application of the standard addition method enabled detection limits of 0.14 µM for iodide and 0.02 µM for iodate, together with the direct introduction of the target water samples, coastal and inland bathing waters. The results obtained were in agreement with those obtained by ICP-MS and a colorimetric reference procedure. Recovery tests also confirmed the accuracy of the developed method which was effectively applied to bathing waters and seaweed extracts. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Transient performance analysis of pressurized safety injection tank with a partition

    International Nuclear Information System (INIS)

    Bae, Youngmin; Kim, Young In; Kim, Keung Koo

    2015-01-01

    Highlights: • Functional performance of safety injection tanks with a partition is evaluated. • Effects of key design parameters are scrutinized. • Distinctive features of the flow in multi-unit safety injection tanks are explored. - Abstract: A parametric study has been performed to evaluate the functional performance of a pressurized multi-unit safety injection tank, which would be considered as one of the candidates for a passive safety injection system in a nuclear power plant. The influences of key design parameters including the orifice size, initial gas fraction, and resistance coefficients and operating condition on the injection flow rate are scrutinized with a discussion of the relevant flow features such as the choked flow of gas through an orifice and two interconnected regions of differing gaseous pressure. The obtained results indicate that a multi-unit safety injection tank can passively control the injection flow rate and provide a stable safety injection over a relatively long period even in the case of drastic depressurization of a reactor coolant system

  6. Tracer techniques for determination of groundwater flow parameters

    International Nuclear Information System (INIS)

    Drost, W.; Klotz, D.

    1988-05-01

    The most common one-borehole and multiple borehole methods using tracers for the direct determination of the groundwater flow parameters (velocity of flow, flow direction) and for the indirect determination of characteristic quantities of the aquifer (effective porosity, dispersivity, transmissivity) are presented methodically and their value is documented by practical examples. Especially, the properties of and measuring technique with suitable tracers are considered (e.g. T, Na-24, Cr-51, Co-58, Co-60, Br-82, Tc-99, I-125, I-131, Au-198). (orig./HP) [de

  7. Urinary bladder blood flow. I. Comparison of clearance of locally injected 99mtechnetium pertechnate and radioactive microsphere technique in dogs

    DEFF Research Database (Denmark)

    Krøyer, Kristian; Bülow, J; Nielsen, S L

    1990-01-01

    The blood flow of the dog urinary bladder measured by radioactive microsphere technique was compared to the clearance of locally injected 99mTechnetium pertechnate (99mTc) in the bladder wall. In semilogarithmic plots the 99mTc washout curves showed a multiexponential course. From the initial...... slopes (median 5.7 min) the bladder blood flow was calculated to be only 30-62% of the results obtained from the radioactive microsphere technique (blood flow in the muscular layer 21.7-44.8 ml/100 g/min). These lower values imply that the rate of removal of the hydrophilic tracer 99mTc at these flow...... blood flow....

  8. A Customizable Flow Injection System for Automated, High Throughput, and Time Sensitive Ion Mobility Spectrometry and Mass Spectrometry Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Orton, Daniel J. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Tfaily, Malak M. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Moore, Ronald J. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; LaMarche, Brian L. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Zheng, Xueyun [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Fillmore, Thomas L. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Chu, Rosalie K. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Weitz, Karl K. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Monroe, Matthew E. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Kelly, Ryan T. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Smith, Richard D. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States; Baker, Erin S. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, United States

    2017-12-13

    To better understand disease conditions and environmental perturbations, multi-omic studies (i.e. proteomic, lipidomic, metabolomic, etc. analyses) are vastly increasing in popularity. In a multi-omic study, a single sample is typically extracted in multiple ways and numerous analyses are performed using different instruments. Thus, one sample becomes many analyses, making high throughput and reproducible evaluations a necessity. One way to address the numerous samples and varying instrumental conditions is to utilize a flow injection analysis (FIA) system for rapid sample injection. While some FIA systems have been created to address these challenges, many have limitations such as high consumable costs, low pressure capabilities, limited pressure monitoring and fixed flow rates. To address these limitations, we created an automated, customizable FIA system capable of operating at diverse flow rates (~50 nL/min to 500 µL/min) to accommodate low- and high-flow instrument sources. This system can also operate at varying analytical throughputs from 24 to 1200 samples per day to enable different MS analysis approaches. Applications ranging from native protein analyses to molecular library construction were performed using the FIA system. The results from these studies showed a highly robust platform, providing consistent performance over many days without carryover as long as washing buffers specific to each molecular analysis were utilized.

  9. Flow Injection Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    1998-01-01

    Learning objectives:* To provide an introduction to automated assays* To describe the basic principles of FIA * To demonstrate the capabilities of FIA in relation to batch assays and conventional continuous flow systems* To show that FIA allows one to augment existing analytical techniques* To sh...... how FIA offers novel analytical procedures which are not feasible by conventional means* To hightlight the potentials of FIA in selected practical assays...

  10. Flow regime effects on non-cavitating injection nozzles over spray behavior

    Energy Technology Data Exchange (ETDEWEB)

    Payri, R., E-mail: rpayri@mot.upv.e [CMT-Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, Valencia E-46022 (Spain); Salvador, F.J.; Gimeno, J.; Novella, R. [CMT-Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, Valencia E-46022 (Spain)

    2011-02-15

    This paper deals with the influence of flow regime (laminar, transition or turbulent) on the internal flow behavior, and how it affects the spray development in diesel nozzles. In particular, the research described here aims at studying and quantifying the internal flow regime effects on the spray behavior. With this purpose, internal flow results, based on mass flow rate and momentum flux measurements performed on three different tapered nozzles and which helped to determine the flow regime, has been taken into account as a point of departure for the spray behavior analysis. Thus, in this work, spray macroscopic visualization tests have been performed and analyzed which clearly revealed a change in the behavior of the angle and penetration of the spray related to the change of the flow nature. Moreover, with all the experimental data available, it has been possible to relate macroscopic parameters of the spray with those describing the internal flow (momentum and effective velocity) or the geometry of the nozzle (length or diameter) through correlations.

  11. Single injection 51Cr EDTA plasma clearance determination in children using capillary blood samples

    International Nuclear Information System (INIS)

    Broechner-Mortensen, J.; Christoffersen, J.

    1977-01-01

    The reliability of a determination of the total 51 Cr EDTA plasma clearance (e) (and with it the glomerular filtration rate), by a simplified single injection method (injected dose: 4.5 μCi per kg b.w.) using capillary blood samples (0.2 ml), was investigated in twenty children. Clearance values determined from capillary blood samples did not differ significantly from those measured simultaneously from venous blood samples, the mean ratio+-SD being 1.02+-0.06(n = 10). The reproducibility (total day-to-day variation) of E determined from capillary blood samples was 6.7% in children with decreased renal function (n = 3) and 6.9% in children with normal renal function (n = 7). The present data indicate that the use of capillary blood samples is an accurate and very precise approach for determination of E in children. (Auth.)

  12. Development of a Sequential Injection Analysis System for the Determination of Saccharin

    Directory of Open Access Journals (Sweden)

    Budi Wibowotomo

    2017-12-01

    Full Text Available Saccharin is a powerfully sweet nonnutritive sweetener that has been approved for food-processing applications within the range of 100–1200 mg/kg. A simple, rapid, and cost-effective sequential injection analysis (SIA technique was developed to determine the saccharin level. This method is based on the reaction of saccharin with p-chloranil in an ethanol medium with a hydrogen peroxide (H2O2 acceleration, and the resultant violet-red compound was detected using a UV-Vis spectrophotometer at λmax = 420 nm. To ascertain the optimal conditions for the SIA system, several parameters were investigated, including buffer flow rate and volume, p-chloranil concentration, and reactant volumes (saccharin, p-chloranil, and H2O2. The optimum setup of the SIA system was achieved with a buffer flow rate, buffer volume, and draw-up time of 1.2 mL/min, 2900 µL, and ~145 s, respectively. The optimal p-chloranil concentration is 30 mM, and the best reactant volumes, presented in an ordered sequence, are as follows: 30 µL of H2O2, 450 µL of saccharin, and 150 µL of p-chloranil. The optimized SIA configuration produced a good linear calibration curve with a correlation coefficient (R2 = 0.9812 in the concentration range of 20–140 mg/L and with a detection limit of 19.69 mg/L. Analytical applications in different food categories also showed acceptable recovery values in the range of 93.1–111.5%. This simple and rapid SIA system offers great feasibility for the saccharin quality control in food-product processing.

  13. Injection dynamics of gelled propellants

    Science.gov (United States)

    Yoon, Changjin

    Gel propellants have been recognized as attractive candidates for future propulsion systems due to the reduced tendency to spill and the energy advantages over solid propellants. One of strong benefits emphasized in gel propellant applications is a throttling capability, but the accurate flow control is more complicated and difficult than with conventional Newtonian propellants because of the unique rheological behaviors of gels. This study is a computational effort directed to enhance understanding of the injector internal flow characteristics for gel propellants under rocket injection conditions. In simulations, the emphasized rheology is a shear-thinning which represents a viscosity decrease with increasing a shear rate. It is described by a generalized Newtonian fluid constitutive equation and Carreau-Yasuda model. Using this rheological model, two injection schemes are considered in the present study: axially-fed and cross-fed injection for single-element and multi-element impinging injectors, respectively. An axisymmetric model is developed to describe the axially-fed injector flows and fully three-dimensional model is utilized to simulate cross-fed injector flows. Under axially-fed injection conditions investigated, three distinct modes, an unsteady, steady, and hydraulic flip mode, are observed and mapped in terms of Reynolds number and orifice design. In an unsteady mode, quasi-periodic oscillations occur near the inlet lip leading mass pulsations and viscosity fluctuations at the orifice exit. This dynamic behavior is characterized using a time-averaged discharge coefficient, oscillation magnitude and frequency by a parametric study with respect to an orifice design, Reynolds number and rheology. As a result, orifice exit flows for gel propellants appear to be significantly influenced by a viscous damping and flow resistance due to a shear thinning behavior and these are observed in each factors considered. Under conditions driven by a manifold crossflow

  14. Effect of intracoronary nitroprusside injection on flow recovery during primary PCI in acute STEMI patients.

    Science.gov (United States)

    Yang, Lixia; Mu, Lihua; Sun, Linhui; Qi, Feng; Guo, Ruiwei

    2017-04-01

    The no/slow reflow phenomenon during primary percutaneous coronary intervention (PPCI) causes the destruction of the coronary microcirculation and further myocardial damage. Some studies have shown that intracoronary nitroprusside infusion is a safe and effective method for managing the no/slow reflow phenomenon. However, it is uncertain whether the injection of nitroprusside at a specific time point during PPCI can most effectively prevent no-reflow. In this study, we investigated the effect of the timing of an intracoronary nitroprusside injection on flow recovery during PPCI in patients with ST elevation acute myocardial infarction (STEMI). One hundred twenty consecutive patients with STEMI who underwent PPCI were enrolled in the study. Patients who fulfilled the eligibility criteria were randomly allocated to three groups: control group (N.=40) received no nitroprusside before they completed PCI; the second group (N.=40) received nitroprusside before balloon dilatation; and the third group (N.=40) received nitroprusside after each balloon dilatation and before contrast agent refilling. The baseline clinical variables and the details of the PCI procedure were collected. The thrombolysis in myocardial infarction (TIMI) flow grades and the corrected TIMI frame count (cTFC) were evaluated immediately after stent implantation was completed. There were no significant differences in the baseline characteristics, antithrombotic drugs given before PCI, and details of the PCI procedure among the three groups (P>0.05). The incidence of TIMI grade 3 after PCI was significantly higher in the nitroprusside group than in the control group (P=0.025), whereas cTFC was significantly lower in the nitroprusside group (26.6±15.2) than in the control group (38.1±21.3, P=0.001). The incidence of TIMI grade 3 after PCI was significantly higher in the third group than in the second group (P=0.045), and cTFC was significantly lower in the third group (21.5±9.5) than in the second

  15. Determination of adipose tissue blood flow with local 133Xe clearance. Evaluation of a new labelling technique

    DEFF Research Database (Denmark)

    Simonsen, Lene; Enevoldsen, Lotte Hahn; Bülow, Jens

    2003-01-01

    Adipose tissue blood flow was measured in six healthy, non-obese subjects with the xenon wash-out technique after labelling of the tissue by either injection of 133Xe dissolved in isotonic sodium chloride (water depot) or injection of 133Xe in gas form (gas depot). The wash-out rates were...

  16. Stall margin improvement of an axial flow fan with end wall injection and suction; Hekimen fukidashi suidashi ni yoru han'yo jikuryu sofuki no shissoku kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Nishioka, K.; Kuroda, H.; Obata, S.; Chimura, O. [National Defense Academy, Kanagawa (Japan)

    1999-06-25

    The experimental studies are conducted to reveal the mechanism of stall margin improvement of an axial flow fan by injection or suction from the end wall. In case of injection, the largest improvement is obtained by the injection at about 0. 14 {approx} 0 .21 times axial chord length downstream from leading edge. The reason for large improvement is that stall vortex, shed intermittent separation vortex and tip leakage vortex are dissipated by this injection, and also that this blowing suppresses the separation of boundary layer. In case of suction, the largest improvement is found for the suction from the end wall near leading edge. The amplitude of periodic static pressure after stall inception becomes smaller in comparison with injection cases. These effects are increased with the increase of suction flow rate, because the discharge of the vortex occurs more easily. On the other hand, the suction from the upstream of leading edge reduces the axial velocity near rotor tip, and then it induces stall. Also we tried to visualize the tip region flow, The suppression mechanism is discussed based on the visualization. The suppression of stall is successfully photographed. (author)

  17. [Study on Content Determination of Lead and Arsenic in Four Traditional Tibetan Medicine Prescription Preparations by Wet Digestion Flow Injection-Hydride Generation-Atomic Absorption Spectrometry].

    Science.gov (United States)

    Zheng, Zhi-yuan; Du, Yu-zhi; Zhang, Ming; Yu, Ming-jie; Li, Cen; Yang, Hong-xia; Zhao, Jing; Xia, Zheng-hua; Wei, Li-xin

    2015-04-01

    Four common traditional tibetan medicine prescription preparations "Anzhijinghuasan, Dangzuo, Renqingchangjue and Rannasangpei" in tibetan areas were selected as study objects in the present study. The purpose was to try to establish a kind of wet digestion and flow injection-hydride generation-atomic absorption spectrometry (FI-HAAS) associated analysis method for the content determinations of lead and arsenic in traditional tibetan medicine under optimized digestion and measurement conditions and determine their contents accurately. Under these optimum operating conditions, experimental results were as follows. The detection limits for lead and arsenic were 0.067 and 0.012 µg · mL(-1) respectively. The quantification limits for lead and arsenic were 0.22 and 0.041 µg · mL(-1) respectively. The linear ranges for lead and arsenic were 25-1,600 ng · mL(-1) (r = 0.9995) and 12.5-800 ng · mL(-1) (r = 0.9994) respectively. The degrees of precision(RSD) for lead and arsenic were 2.0% and 3.2% respectively. The recovery rates for lead and arsenic were 98.00%-99.98% and 96.67%-99.87% respectively. The content determination results of lead and arsenic in four traditional tibetan medicine prescription preparations were as fol- lows. The contents of lead and arsenic in Anzhijinghuasan are 0.63-0.67 µg · g(-1) and 0.32-0.33 µg · g(-1) in Anzhijinghua- san, 42.92-43.36 µg · g(-1) and 24.67-25.87 µg · g(-1) in Dangzuo, 1,611. 39-1,631.36 µg · g(-1) and 926.76-956.52 µg- g(-1) in Renqing Changjue, and 1,102.28-1,119.127 µg-g(-1) and 509.96-516.87 µg · g(-1) in Rannasangpei, respectively. This study established a method for content determination of lead and arsenic in traditional tibetan medicine, and determined the content levels of lead and arsenic in four tibetan medicine-prescription preparations accurately. In addition, these results also provide the basis for the safe and effective use of those medicines in clinic.

  18. Comparison of Flow Injection MS, NMR, and DNA Sequencing: Methods for Identification and Authentication of Black Cohosh (Actaea racemosa)

    Science.gov (United States)

    Flow injection mass spectrometry (FIMS) and proton nuclear magnetic resonance spectrometry (1H-NMR), two metabolic fingerprinting methods, and DNA sequencing were used to identify and authenticate Actaea species. Initially, samples of Actaea racemosa L. from a single source were distinguished from ...

  19. Combustion characteristics and optimal factors determination with Taguchi method for diesel engines port-injecting hydrogen

    International Nuclear Information System (INIS)

    Wu, Horng-Wen; Wu, Zhan-Yi

    2012-01-01

    This study applies the L 9 orthogonal array of the Taguchi method to find out the best hydrogen injection timing, hydrogen-energy-share ratio, and the percentage of exhaust gas circulation (EGR) in a single DI diesel engine. The injection timing is controlled by an electronic control unit (ECU) and the quantity of hydrogen is controlled by hydrogen flow controller. For various engine loads, the authors determine the optimal operating factors for low BSFC (brake specific fuel consumption), NO X , and smoke. Moreover, net heat-release rate involving variable specific heat ratio is computed from the experimental in-cylinder pressure. In-cylinder pressure, net heat-release rate, A/F ratios, COV (coefficient of variations) of IMEP (indicated mean effective pressure), NO X , and smoke using the optimum condition factors are compared with those by original baseline diesel engine. The predictions made using Taguchi's parameter design technique agreed with the confirmation results on 95% confidence interval. At 45% and 60% loads the optimum factor combination compared with the original baseline diesel engine reduces 14.52% for BSFC, 60.5% for NO X and for 42.28% smoke and improves combustion performance such as peak in-cylinder pressure and net heat-release rate. Adding hydrogen and EGR would not generate unstable combustion due to lower COV of IMEP. -- Highlights: ► We use hydrogen injector controlled by ECU and cooled EGR system in a diesel engine. ► Optimal factors by Taguchi method are determined for low BSFC, NO X and smoke. ► The COV of IMEP is lower than 10% so it will not cause the unstable combustion. ► We improve A/F ratio, in-cylinder pressure, and heat-release at optimized engine. ► Decrease is 14.5% for BSFC, 60.5% for NO X , and 42.28% for smoke at optimized engine.

  20. In situ permeable flow sensors at the Savannah River Integrated Demonstration: Phase 2 results

    International Nuclear Information System (INIS)

    Ballard, S.

    1994-08-01

    A suite of In Situ Permeable Flow Sensors was deployed at the site of the Savannah River Integrated Demonstration to monitor the interaction between the groundwater flow regime and air injected into the saturated subsurface through a horizontal well. One of the goals of the experiment was to determine if a groundwater circulation system was induced by the air injection process. The data suggest that no such circulation system was established, perhaps due to the heterogeneous nature of the sediments through which the injected gas has to travel. The steady state and transient groundwater flow patterns observed suggest that the injected air followed high permeability pathways from the injection well to the water table. The preferential pathways through the essentially horizontal impermeable layers appear to have been created by drilling activities at the site

  1. Mathematical Model of Two Phase Flow in Natural Draft Wet-Cooling Tower Including Flue Gas Injection

    Directory of Open Access Journals (Sweden)

    Hyhlík Tomáš

    2016-01-01

    Full Text Available The previously developed model of natural draft wet-cooling tower flow, heat and mass transfer is extended to be able to take into account the flow of supersaturated moist air. The two phase flow model is based on void fraction of gas phase which is included in the governing equations. Homogeneous equilibrium model, where the two phases are well mixed and have the same velocity, is used. The effect of flue gas injection is included into the developed mathematical model by using source terms in governing equations and by using momentum flux coefficient and kinetic energy flux coefficient. Heat and mass transfer in the fill zone is described by the system of ordinary differential equations, where the mass transfer is represented by measured fill Merkel number and heat transfer is calculated using prescribed Lewis factor.

  2. Determination of Trace Anions in Concentrated Hydrogen Peroxide by Direct Injection Ion Chromatography with Conductivity Detection after Pt-Catalyzed On-Line Decomposition

    International Nuclear Information System (INIS)

    Kim, Do Hee; Lee, Bo Kyung; Lee, Dong Soo

    1999-01-01

    A method has been developed for the determination of trace anion impurities in concentrated hydrogen peroxide. The method involves on-line decomposition of hydrogen peroxide, ion chromatographic separation and subsequent suppressed-type conductivity detection. H 2 O 2 is decomposed in Pt-catalyst filled Gore-Tex membrane tubing and the resulting aqueous solution containing analytes is introduced to the injection valve of an ion chromatograph for periodic determinations. The oxygen gas evolving within the membrane tubing escapes freely through the membrane wall causing no problem in ion chromatographic analysis. Decomposition efficiency is above 99.99% at a flow rate of 0.4mL/min for a 30% hydrogen peroxide concentration. Analytes are quantitatively retained. The analysis results for several brands of commercial hydrogen peroxides are reported

  3. Research on injection characteristics of venturi scrubber worked in self-priming mode

    International Nuclear Information System (INIS)

    Zhou Yanmin; Sun Zhongning; Gu Haifeng; Miao Zhuang

    2015-01-01

    The injection characteristics of Venturi scrubber worked in self-priming mode in containment filter venting system was studied experimentally under different air flows, liquid levels and system pressures. The results indicate that with the increase of superficial gas velocity in throat, the static pressure drop of both sides of the suction grows approximately following a parabolic law, and the injection flow rate injecting into the Venturi scrubber increases linearly. The effect of liquid level on injection characteristics relates closely with the relative position to the outlet of the Venturi scrubber. When the liquid level is below the outlet, the injection flow rate improves significantly with increasing liquid level and presents a partition phenomenon, and in the low throat velocity, the increase of liquid level is more effective to improve the injection flow rate. However, when the liquid level is above the outlet, it almost has no impact on the injection flow rate. The pressure is another important factor affecting the injection characteristic of self-priming Venturi scrubber, which is mainly caused by the change on gas density. In the range of 0.150 kPa, with the increase of pressure, the injection flow rate improves greatly and the influence of pressure is more obvious in high throat velocity than in low throat velocity. (authors)

  4. Spectrophotometric determination of Tl carrier in 201Tl-TlCl injection

    International Nuclear Information System (INIS)

    Gong Quansheng; Jing Lie

    1997-01-01

    A simple and sensitive method for the spectrophotometric determination of carrier content (Thallium) in 201 Tl-TlCl injection is described. Thallium (I) is oxidised to Thallium (III) by aqueous bromine, then excess bromine is removed by adding sulfosalicylic acid. In buffer solution (NH 4 Cl-NH 4 OH) at pH 11.7 with the presence of emulsifier OP, thallium (III) and cadion form a complex having an absorption maximum at 469 nm with a molar absorptivity of 1.37 x 10 4 m 2 /mol. Beer's law is obeyed in the concentration range of 0-7 μg/5 mL. The effect of impurity elements in 201 Tl-TlCl injection is examined. It is an ideal method for the analysis of radioactive solution

  5. On-line Speciation of Cr(III) and Cr(VI) by Flow Injection Analysis With Spectrophotometric Detection and Chemometrics

    DEFF Research Database (Denmark)

    Diacu, Elena; Andersen, Jens Enevold Thaulov

    2003-01-01

    A flow injection system has been developed, for on-line speciation. of Cr(III) and Cr(VI) by the Diphenylcarbazide (DPC) method with H2O2 oxidation followed by spectrophotometric detection at the 550 nm wavelength. The data thus obtained were subjected to a chemometric analysis (PLS), which showe...

  6. 78 FR 14095 - Determination That GEREF (Sermorelin Acetate) Injection, 0.5 Milligrams Base/Vial and 1.0...

    Science.gov (United States)

    2013-03-04

    ...] Determination That GEREF (Sermorelin Acetate) Injection, 0.5 Milligrams Base/Vial and 1.0 Milligrams Base/Vial, and GEREF (Sermorelin Acetate) Injection, 0.05 Milligrams Base/Amp, Were Not Withdrawn From Sale for...

  7. Vascular structure determines pulmonary blood flow distribution

    Science.gov (United States)

    Hlastala, M. P.; Glenny, R. W.

    1999-01-01

    Scientific knowledge develops through the evolution of new concepts. This process is usually driven by new methodologies that provide observations not previously available. Understanding of pulmonary blood flow determinants advanced significantly in the 1960s and is now changing rapidly again, because of increased spatial resolution of regional pulmonary blood flow measurements.

  8. Injection and swirl driven flowfields in solid and liquid rocket motors

    Science.gov (United States)

    Vyas, Anand B.

    In this work, we seek approximate analytical solutions to describe the bulk flow motion in certain types of solid and liquid rocket motors. In the case of an idealized solid rocket motor, a cylindrical double base propellant grain with steady regression rate is considered. The well known inviscid profile determined by Culick is extended here to include the effects of viscosity and steady grain regression. The approximate analytical solution for the cold flow is obtained from similarity principles, perturbation methods and the method of variation of parameters. The velocity, vorticity, pressure gradient and the shear stress distributions are determined and interpreted for different rates of wall regression and injection Reynolds number. The liquid propellant rocket engine considered here is based on a novel design that gives rise to a cyclonic flow. The resulting bidirectional motion is triggered by the tangential injection of an oxidizer just upstream of the chamber nozzle. Velocity, vorticity and pressure gradient distributions are determined for the bulk gas dynamics using a non-reactive inviscid model. Viscous corrections are then incorporated to explain the formation of a forced vortex near the core. Our results compare favorably with numerical simulations and experimental measurements obtained by other researchers. They also indicate that the bidirectional vortex in a cylindrical chamber is a physical solution of the Euler equations. In closing, we investigate the possibility of multi-directional flow behavior as predicted by Euler's equation and as reported recently in laboratory experiments.

  9. A Customizable Flow Injection System for Automated, High Throughput, and Time Sensitive Ion Mobility Spectrometry and Mass Spectrometry Measurements.

    Science.gov (United States)

    Orton, Daniel J; Tfaily, Malak M; Moore, Ronald J; LaMarche, Brian L; Zheng, Xueyun; Fillmore, Thomas L; Chu, Rosalie K; Weitz, Karl K; Monroe, Matthew E; Kelly, Ryan T; Smith, Richard D; Baker, Erin S

    2018-01-02

    To better understand disease conditions and environmental perturbations, multiomic studies combining proteomic, lipidomic, and metabolomic analyses are vastly increasing in popularity. In a multiomic study, a single sample is typically extracted in multiple ways, and various analyses are performed using different instruments, most often based upon mass spectrometry (MS). Thus, one sample becomes many measurements, making high throughput and reproducible evaluations a necessity. One way to address the numerous samples and varying instrumental conditions is to utilize a flow injection analysis (FIA) system for rapid sample injections. While some FIA systems have been created to address these challenges, many have limitations such as costly consumables, low pressure capabilities, limited pressure monitoring, and fixed flow rates. To address these limitations, we created an automated, customizable FIA system capable of operating at a range of flow rates (∼50 nL/min to 500 μL/min) to accommodate both low- and high-flow MS ionization sources. This system also functions at varying analytical throughputs from 24 to 1200 samples per day to enable different MS analysis approaches. Applications ranging from native protein analyses to molecular library construction were performed using the FIA system, and results showed a highly robust and reproducible platform capable of providing consistent performance over many days without carryover, as long as washing buffers specific to each molecular analysis were utilized.

  10. DIFFERENTIATION OF AURANTII FRUCTUS IMMATURUS AND FRUCTUS PONICIRI TRIFOLIATAE IMMATURUS BY FLOW-INJECTION WITH ULTRAVIOLET SPECTROSCOPIC DETECTION AND PROTON NUCLEAR MAGNETIC RESONANCE USING PARTIAL LEAST-SQUARES DISCRIMINANT ANALYSIS.

    Science.gov (United States)

    Zhang, Mengliang; Zhao, Yang; Harrington, Peter de B; Chen, Pei

    2016-03-01

    Two simple fingerprinting methods, flow-injection coupled to ultraviolet spectroscopy and proton nuclear magnetic resonance, were used for discriminating between Aurantii fructus immaturus and Fructus poniciri trifoliatae immaturus . Both methods were combined with partial least-squares discriminant analysis. In the flow-injection method, four data representations were evaluated: total ultraviolet absorbance chromatograms, averaged ultraviolet spectra, absorbance at 193, 205, 225, and 283 nm, and absorbance at 225 and 283 nm. Prediction rates of 100% were achieved for all data representations by partial least-squares discriminant analysis using leave-one-sample-out cross-validation. The prediction rate for the proton nuclear magnetic resonance data by partial least-squares discriminant analysis with leave-one-sample-out cross-validation was also 100%. A new validation set of data was collected by flow-injection with ultraviolet spectroscopic detection two weeks later and predicted by partial least-squares discriminant analysis models constructed by the initial data representations with no parameter changes. The classification rates were 95% with the total ultraviolet absorbance chromatograms datasets and 100% with the other three datasets. Flow-injection with ultraviolet detection and proton nuclear magnetic resonance are simple, high throughput, and low-cost methods for discrimination studies.

  11. Pellet ablation and cloud flow characteristics in the JIPP T-IIU plasma with the injection-angle controllable system

    International Nuclear Information System (INIS)

    Sakakita, H.; Sato, K.N.; Liang, R.; Hamada, Y.; Ando, A.; Kano, Y.; Sakamoto, M.

    1994-01-01

    Pellet ablation and flow characteristics of ablation cloud have been studied in the JIPP T-IIU plasma by using an injection-angle controllable system. A new technique for an ice pellet injection system with controllability of injection angle has been developed and installed to the JIPP T-IIU tokamak in order to vary deposition profile of ice pellets within a plasma. Injection angle can be varied easily and successfully during an interval of two plasma shots in the course of an experiment, so that one can carry out various basic experiments by varying the pellet deposition profile. The injection angle has been varied poloidally from -6 to 6 degree by changing the angle of the last stage drift tube. This situation makes possible for pellets to aim at from about r = -2a/3 to r = 2a/3 of the plasma. From two dimensional observations by CCD cameras, details of the pellet ablation structures with various injection angles have been studied, and a couple of interesting phenomena have been found. In the case of an injection angle (θ) larger than a certain value (θ ≥ 4 o ), a pellet penetrates straightly through the plasma with a trace of straight ablation cloud, which has been expected from usual theoretical consideration. On the other hand, a long helical tail of ablation light has been observed in the case of the angle smaller than the certain value (θ ≤ 4 o ). (author) 4 refs., 4 figs

  12. The Determinants of International News Flow: A Network Analysis.

    Science.gov (United States)

    Kim, Kyungmo; Barnett, George A.

    1996-01-01

    Examines the structure of international news flow and its determinants. Reveals inequality of international news flow between core and periphery, with Western industrialized countries at the center. Finds that the news flow network is structured into eight geographic-linguistic groups. Indicates flow is influenced by a country's economic…

  13. Numerical investigation on the effect of injection pressure on the internal flow characteristics for diethyl ether, dimethyl ether and diesel fuel injectors using CFD

    Directory of Open Access Journals (Sweden)

    Vijayakumar Thulasi

    2011-01-01

    Full Text Available The spray characteristics of the diesel fuel are greatly affected by the cavitation formed inside the injector due to the high pressure differential across the nozzle. Many researchers across the globe are exploring the potential of using diethyl ether and dimethyl ether as an alternate for diesel fuel to meet the strict emission norms. Due to the variation in the fuel properties the internal flow characteristics in injectors for ether fuels are expected to be different from that of the diesel fuel. In this paper computational technique is used to study and compare the internal flow characteristics of diethyl ether, dimethyl ether and diesel fuel. The two phase flow model considering the fuel as a mixture of liquid and vapor is adopted for the simulation study. The injection pressure is varied from 100 to 400 bar and the flow characteristics of all three fuels are simulated and compared. Results indicate that all three fuels have distinct cavitating patterns owing to different property values. The dimethyl ether is found to be more cavitating than diesel and diethyl ether fuels as expected. The mass of fuel injected are found to be decreasing for the ether fuels when compared with diesel fuel at all injection pressures.

  14. Remote calorimetric detection of urea via flow injection analysis.

    Science.gov (United States)

    Gaddes, David E; Demirel, Melik C; Reeves, W Brian; Tadigadapa, Srinivas

    2015-12-07

    The design and development of a calorimetric biosensing system enabling relatively high throughput sample analysis are reported. The calorimetric biosensor system consists of a thin (∼20 μm) micromachined Y-cut quartz crystal resonator (QCR) as a temperature sensor placed in close proximity to a fluidic chamber packed with an immobilized enzyme. Layer by layer enzyme immobilization of urease is demonstrated and its activity as a function of the number of layers, pH, and time has been evaluated. This configuration enables a sensing system where a transducer element is physically separated from the analyte solution of interest and is thereby free from fouling effects typically associated with biochemical reactions occuring on the sensor surface. The performance of this biosensing system is demonstrated by detection of 1-200 mM urea in phosphate buffer via a flow injection analysis (FIA) technique. Miniaturized fluidic systems were used to provide continuous flow through a reaction column. Under this configuration the biosensor has an ultimate resolution of less than 1 mM urea and showed a linear response between 0-50 mM. This work demonstrates a sensing modality in which the sensor itself is not fouled or contaminated by the solution of interest and the enzyme immobilized Kapton® fluidic reaction column can be used as a disposable cartridge. Such a system enables reuse and reliability for long term sampling measurements. Based on this concept a biosensing system is envisioned which can perform rapid measurements to detect biomarkers such as glucose, creatinine, cholesterol, urea and lactate in urine and blood continuously over extended periods of time.

  15. Preliminary study on functional performance of compound type multistage safety injection tank

    International Nuclear Information System (INIS)

    Bae, Youngmin; Kim, Young In; Kim, Keung Koo

    2015-01-01

    Highlights: • Functional performance of compound type multistage safety injection tanks is studied. • Effects of key design parameters are scrutinized. • Distinctive flow features in compound type safety injection tanks are explored. - Abstract: A parametric study is carried out to evaluate the functional performance of a compound type multistage safety injection tank that would be considered one of the components for the passive safety injection systems in nuclear power plants. The effects of key design parameters such as the initial volume fraction and charging pressure of gas, tank elevation, vertical location of a sparger, resistance coefficient, and operating condition on the injection flow rate are scrutinized along with a discussion of the relevant flow features. The obtained results indicate that the compound type multistage safety injection tank can effectively control the injection flow rate in a passive manner, by switching the driving force for the safety injection from gas pressure to gravity during the refill and reflood phases, respectively

  16. Determination of trace amounts of lead by chelating ion exchange and on-line preconcentration in flow-injection atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Purohit, Rajesh; Devi, Surekha

    1992-01-01

    Resins synthesized from quinolin-8-ol and resorcinol or hydro-quinone, with furfuraldehyde, formaldehyde or benzaldehyde as cross-linking agent, were used for the preconcentration of nanogram amounts of lead. The rate of exchange and activation energy of lead exchange were calculated. Column separations of lead-copper and lead-zinc did not show any cross-contamination. A continuous flow manifold using resin microcolumns was developed for the preconcentration and determination of lead. (author). 24 refs.; 5 figs.; 3 tabs

  17. Autologous Pure Platelet-Rich Plasma Dermal Injections for Facial Skin Rejuvenation: Clinical, Instrumental, and Flow Cytometry Assessment.

    Science.gov (United States)

    Cameli, Norma; Mariano, Maria; Cordone, Iole; Abril, Elva; Masi, Serena; Foddai, Maria Laura

    2017-06-01

    Platelet-rich plasma (PRP) is an emerging treatment in dermatology recently proposed for skin rejuvenation. To evaluate the efficacy and safety of autologous pure PRP dermal injections on facial skin rejuvenation, investigating the cellularity of PRP samples. Twelve patients underwent 3 sessions of PRP injection at 1-month intervals. The clinical and instrumental outcomes were evaluated before (T0) and 1 month (T1) after the end of treatment by means of transepidermal water loss, corneometry, Cutometer, Visioscan, and Visioface. A flow cytometry characterization on PRP and peripheral blood (PB) samples was performed. Clinical and patient evaluation showed improvement of skin texture. Skin gross elasticity, skin smoothness parameters, skin barrier function, and capacitance were significantly improved. No difference between PRP and PB lymphocyte immunological asset was observed. A leukocyte population (mainly CD3) and neutrophils depletion were documented in all the PRP samples. This instrumental study demonstrated that PRP poor in leukocytes can provide objective improvements in skin biostimulation. Flow cytometry showed no variability among the PRP samples using a reproducible separation system and a low content in proinflammatory cells. Although a pilot study, it may be helpful for future investigations on PRP cellularity.

  18. Semiempirical method of determining flow coefficients for pitot rake mass flow rate measurements

    Science.gov (United States)

    Trefny, C. J.

    1985-01-01

    Flow coefficients applicable to area-weighted pitot rake mass flow rate measurements are presented for fully developed, turbulent flow in an annulus. A turbulent velocity profile is generated semiempirically for a given annulus hub-to-tip radius ratio and integrated numerically to determine the ideal mass flow rate. The calculated velocities at each probe location are then summed, and the flow rate as indicated by the rake is obtained. The flow coefficient to be used with the particular rake geometry is subsequently obtained by dividing the ideal flow rate by the rake-indicated flow rate. Flow coefficients ranged from 0.903 for one probe placed at a radius dividing two equal areas to 0.984 for a 10-probe area-weighted rake. Flow coefficients were not a strong function of annulus hub-to-tip radius ratio for rakes with three or more probes. The semiempirical method used to generate the turbulent velocity profiles is described in detail.

  19. Determination of flow rates of oil, water and gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Roach, G J; Watt, J S; Zastawny, H W [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lucas Heights, NSW (Australia). Div. of Mineral Physics

    1994-12-31

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs.

  20. Determination of flow rates of oil, water and gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Roach, G.J.; Watt, J.S.; Zastawny, H.W. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lucas Heights, NSW (Australia). Div. of Mineral Physics

    1993-12-31

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs.

  1. Determination of flow rates of oil, water and gas in pipelines

    International Nuclear Information System (INIS)

    Roach, G.J.; Watt, J.S.; Zastawny, H.W.

    1993-01-01

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs

  2. Air-injection field tests to determine the effect of a heat cycle on the permeability of welded tuff

    International Nuclear Information System (INIS)

    Lee, K.H.; Ueng, Tzou-Shin.

    1991-01-01

    As part of a series of prototype tests conducted in preparation for site characterization of the potential nuclear-waste repository site at Yucca Mountain, Nevada, air-injection tests were conducted in the welded tuffs in G-Tunnel at the Nevada Test Site. The objectives were to characterize the permeability of the highly fractured tuff around a horizontal heater emplacement borehole, and to determine the effect of a heating and cooling cycle on the rock-mass permeability. Air was injected into packed-off intervals along the heater borehole. The bulk permeability of the rock adjacent to the test interval and the aperture of fractures intersecting the interval were computed from the air-flow rate, temperature, and pressure at steady state. The bulk permeability of intervals along with borehole varied from a minimum of 0.08 D to a maximum of over 144 D and the equivalent parallel-plate apertures of fractures intersecting the borehole varied from 70 to 589 μm. Higher permeabilities seemed to correlate spatially with the mapped fractures. The rock was then heated for a period of 6.5 months with an electrical-resistive heater installed in the borehole. After heating, the rock was allowed to cool down to the ambient temperature. The highest borehole wall temperature measured was 242 degree C. Air injection tests were repeated following the heating and cooling cycle, and the results showed significant increases in bulk permeability ranging from 10 to 1830% along the borehole. 8 ref., 6 figs., 3 tabs

  3. Numerical Modeling of Geomechanical Processes Related to CO{sub 2} Injection within Generic Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, Andreas

    2013-05-31

    In this project generic anticline structures have been used for numerical modeling analyses to study the influence of geometrical parameters, fluid flow boundary conditions, in situ stress regime and inter-bedding friction coefficient on geomechanical risks such as fracture reactivation and fracture generation. The resulting stress states for these structures are also used to determine safe drilling directions and a methodology for wellbore trajection optimization is developed that is applicable for non-Andersonian stress states. The results of the fluid flow simulation show that the type of fluid flow boundary condition is of utmost importance and has significant impact on all injection related parameters. It is recommended that further research is conducted to establish a method to quantify the fluid flow boundary conditions for injection applications. The results of the geomechanical simulation show that in situ stress regime is a crucial, if not the most important, factor determining geomechanical risks. For extension and strike slip stress regimes anticline structures should be favored over horizontally layered basin as they feature higher ΔP{sub c} magnitudes. If sedimentary basins are tectonically relaxed and their state of stress is characterized by the uni-axial strain model the basin is in exact frictional equilibrium and fluids should not be injected. The results also show that low inter bedding friction coefficients effectively decouple layers resulting in lower ΔP{sub c} magnitudes, especially for the compressional stress regime.

  4. Flow Injection Spectrophotometric Determination of Glyphosate ...

    African Journals Online (AJOL)

    NICOLAAS

    limits and causes digestive tract irritation, eyes and skin irrita- tion, low blood ... techniques, mostly chromatographic, have been developed for ... enhanced photochemically induced fluorescence (MEPIF) .... with glyphosate on the same field or in the nearby fields. .... At 700 µL sample volume two peaks near to each.

  5. Control of Surge in Centrifugal Compressor by Using a Nozzle Injection System: Universality in Optimal Position of Injection Nozzle

    Directory of Open Access Journals (Sweden)

    Toshiyuki Hirano

    2012-01-01

    Full Text Available The passive control method for surge and rotating stall in centrifugal compressors by using a nozzle injection system was proposed to extend the stable operating range to the low flow rate. A part of the flow at the scroll outlet of a compressor was recirculated to an injection nozzle installed on the inner wall of the suction pipe of the compressor through the bypass pipe and injected to the impeller inlet. Two types of compressors were tested at the rotational speeds of 50,000 rpm and 60,000 rpm with the parameter of the circumferential position of the injection nozzle. The present experimental results revealed that the optimum circumferential position, which most effectively reduced the flow rate for the surge inception, existed at the opposite side of the tongue of the scroll against the rotational axis and did not depend on the compressor system and the rotational speeds.

  6. Detection of Total Phenol in Green and Black Teas by Flow Injection System and Unmodified Screen Printed Electrode

    Directory of Open Access Journals (Sweden)

    Ivanildo Luiz de Mattos

    2010-01-01

    Full Text Available A flow injection system using an unmodified gold screen-printed electrode was employed for total phenol determination in black and green teas. In order to avoid passivation of the electrode surface due to the redox reaction, preoxidation of the sample was realized by hexacyanoferrate(III followed by addition of an EDTA solution. The complex formed in the presence of EDTA minimizes or avoids polymerization of the oxidized phenols. The previously filtered tea sample and hexacyanoferrate(III reagent were introduced simultaneously into two-carrier streams producing two reproducible zones. At confluence point, the pre-oxidation of the phenolic compounds occurs while this zone flows through the coiled reactor and receives the EDTA solution before phenol detection. The consumption of ferricyanide was monitorized at 360 mV versus Ag/AgCl and reflected the total amount of phenolic compounds present in the sample. Results were reported as gallic acid equivalents (GAEs. The proposed system is robust, versatile, environmentally-friendly (since the reactive is used only in the presence of the sample, and allows the analysis of about 35–40 samples per hour with detection limit = 1 mg/L without the necessity for surface cleaning after each measurement. Precise results are in agreement with those obtained by the Folin-Ciocalteu method.

  7. A Holistic Framework for Environmental Flows Determination in Hydropower Contexts

    Energy Technology Data Exchange (ETDEWEB)

    McManamay, Ryan A [ORNL; Bevelhimer, Mark S [ORNL

    2013-05-01

    Among the ecological science community, the consensus view is that the natural flow regime sustains the ecological integrity of river systems. This prevailing viewpoint by many environmental stakeholders has progressively led to increased pressure on hydropower dam owners to change plant operations to affect downstream river flows with the intention of providing better conditions for aquatic biological communities. Identifying the neccessary magnitude, frequency, duration, timing, or rate of change of stream flows to meet ecological needs in a hydropower context is challenging because the ecological responses to changes in flows may not be fully known, there are usually a multitude of competing users of flow, and implementing environmental flows usually comes at a price to energy production. Realistically, hydropower managers must develop a reduced set of goals that provide the most benefit to the identified ecological needs. As a part of the Department of Energy (DOE) Water Power Program, the Instream Flow Project (IFP) was carried out by Oak Ridge National Laboratory (ORNL), Pacific Northwest National Laboratory (PNNL), and Argon National Laboratory (ANL) as an attempt to develop tools aimed at defining environmental flow needs for hydropower operations. The application of these tools ranges from national to site-specific scales; thus, the utility of each tool will depend on various phases of the environmental flow process. Given the complexity and sheer volume of applications used to determine environmentally acceptable flows for hydropower, a framework is needed to organize efforts into a staged process dependent upon spatial, temporal, and functional attributes. By far, the predominant domain for determining environmental flows related to hydropower is within the Federal Energy Regulatory Commission (FERC) relicensing process. This process can take multiple years and can be very expensive depending on the scale of each hydropower project. The utility of such a

  8. Transition from annular flow to plug/slug flow in condensation of steam in microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Xiaojun; Cheng, Ping; Wu, Huiying [School of Mechanical and Power Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Shanghai 200240 (China)

    2008-02-15

    A visualization study has been conducted to investigate the transition from annular flow to plug/slug flow in the condensation of steam in two different sets of parallel microchannels, having hydraulic diameters of 90 {mu}m and 136 {mu}m, respectively. The steam in the parallel microchannels was cooled on the bottom by forced convection of water and by natural convection of air from the top. It is found that the location, where the transition from annular flow to plug/slug flow takes place, depends on mass flux and cooling rate of steam. The effects of mass flux and cooling rate on the occurrence frequency of the injection flow in a single microchannel, having a hydraulic diameter of 120 {mu}m and 128 {mu}m, respectively, are investigated. It is found that two different shapes of injection flow occur in the smooth annular flow in microchannels: injection flow with unsteady vapor ligament occurring at low mass flux (or high cooling rate) and injection flow with steady vapor ligament occurring at high mass flux (or low cooling rate). It is also found that increase of steam mass flux, decrease of cooling rate, or decrease of the microchannel diameter tends to enhance instability of the condensate film on the wall, resulting in occurrence of the injection flow further toward the outlet with an increase in occurrence frequency. (author)

  9. Carbon paste electrode modified with silver thimerosal for the potentiometric flow injection analysis of silver(I)

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Hosny [Chemistry Department, Faculty of Science, Cairo University, Cairo (Egypt)]. E-mail: dr_hosny@yahoo.com

    2005-07-27

    The utility of carbon paste electrode modified with silver ethylmercurythiosalicylate (silver thimerosal) in both static mode and flow injection analysis (FIA) is demonstrated. The electrode was fully characterized in terms of composition, response time, thermal stability, usable pH and ionic strength ranges. It has been shown that diisononyl phthalate (DINP) acts as more suitable solvent mediator for preparation of the electrode, which exhibits linear response range to Ag(I) extending from 5.0 x 10{sup -7} to 1.0 x 10{sup -3} M with detection limit of 2.5 x 10{sup -7} M and Nernstian slope of 59.3 {+-} 1.0 mV/decade. The proposed chemically modified carbon paste electrode shows a very good selectivity for Ag(I) over a wide variety of metal ions and successfully used for the determination of the silver content of silver sulphadiazine (burning cream) and developed radiological films. The electrode was also used as an indicator electrode in the potentiometric titration of thiopental and thimerosal with AgNO{sub 3}.

  10. Model and simulation for melt flow in micro-injection molding based on the PTT model

    International Nuclear Information System (INIS)

    Cao, Wei; Kong, Lingchao; Li, Qian; Ying, Jin; Shen, Changyu

    2011-01-01

    Unsteady viscoelastic flows were studied using the finite element method in this work. The Phan-Thien–Tanner (PTT) model was used to represent the rheological behavior of viscoelastic fluids. To effectively describe the microscale effects, the slip boundary condition and surface tension were added to the mathematical model for melt flow in micro-injection molding. The new variational equation of pressure, including the viscoelastic parameters and slip boundary condition, was generalized using integration by parts. A computer code based on the finite element method and finite difference method was developed to solve the melt flow problem. Numerical simulation revealed that the melt viscoelasticity plays an important role in the prediction of melt pressure, temperature at the gate and the succeeding melt front advancement in the cavity. Using the viscoelastic model one can also control the rapid increase in simulated pressure, temperature, and reduce the filling difference among different cavities. The short shot experiments of micro-motor shaft showed that the predicted melt front from the viscoelastic model is in fair agreement with the corresponding experimental results

  11. [Prophylaxis of recurring low-flow priapism : Experimental botulinum neurotoxin injection into the ischiocavernosus muscle].

    Science.gov (United States)

    Reichel, G; Stenner, A

    2018-01-01

    The treatment of recurring low-flow priapism with the usual medications is still unsatisfactory. The case of an otherwise healthy young man experiencing low-flow priapism at the age of 31 is presented. A reason for his condition could not be identified. Over the course of several months, he required emergency urological treatment more than ten times. Treatment with cyproterone acetate (Androcur® 50 mg/day) stopped the spontaneous erections, but resulted in erectile impotence, reduced motivation, decreased interest in sex, weight gain of 10 kg, breast enlargement combined with touch sensitivity on both sides, and hair loss on both legs. In addition, the patient complained about painful cramps in his pelvic muscles. After appropriate explanations he agreed to try botulinum neurotoxin injections into both ischiocavernosus muscles. The objective was to reduce muscle tone in order to improve venous drainage of blood from the penis. The latest relapse of priapism occurred more than 6 months ago.

  12. Evolution and transition mechanisms of internal swirling flows with tangential entry

    Science.gov (United States)

    Wang, Yanxing; Wang, Xingjian; Yang, Vigor

    2018-01-01

    The characteristics and transition mechanisms of different states of swirling flow in a cylindrical chamber have been numerically investigated using the Galerkin finite element method. The effects of the Reynolds number and swirl level were examined, and a unified theory connecting different flow states was established. The development of each flow state is considered as a result of the interaction and competition between basic mechanisms: (1) the centrifugal effect, which drives an axisymmetric central recirculation zone (CRZ); (2) flow instabilities, which develop at the free shear layer and the central solid-body rotating flow; (3) the bouncing and restoring effects of the injected flow, which facilitate the convergence of flow on the centerline and the formation of bubble-type vortex breakdown; and (4) the damping effect of the end-induced flow, which suppresses the development of the instability waves. The results show that the CRZ, together with the free shear layer on its surface, composes the basic structure of swirling flow. The development of instability waves produces a number of discrete vortex cores enclosing the CRZ. The azimuthal wave number is primarily determined by the injection angle. Generally, the wave number is smaller at a higher injection angle, due to the reduction of the perimeter of the free shear layer. At the same time, the increase in the Reynolds number facilitates the growth of the wave number. The end-induced flow tends to reduce the wave number near the head end and causes a change in wave number from the head end to the downstream region. Spiral-type vortex breakdown can be considered as a limiting case at a high injection angle, with a wave number equal to 0 near the head end and equal to 1 downstream. At lower Reynolds numbers, the bouncing and restoring effect of the injected flow generates bubble-type vortex breakdown.

  13. Carbon dioxide fluid-flow modeling and injectivity calculations

    Science.gov (United States)

    Burke, Lauri

    2011-01-01

    At present, the literature lacks a geologic-based assessment methodology for numerically estimating injectivity, lateral migration, and subsequent long-term containment of supercritical carbon dioxide that has undergone geologic sequestration into subsurface formations. This study provides a method for and quantification of first-order approximations for the time scale of supercritical carbon dioxide lateral migration over a one-kilometer distance through a representative volume of rock. These calculations provide a quantified foundation for estimating injectivity and geologic storage of carbon dioxide.

  14. Developments in Pulsed Neutron Activation for Determination of Water Flow in Pipes

    CERN Document Server

    Mattsson, H

    2003-01-01

    In PNA (pulsed neutron activation) it is important that the measured data can be related to the total mass flow. In this thesis two fundamental problems of the measurement technique and data treatment have been investigated: transport/mixing and background radiation. The principle of PNA is to introduce a radioactive substance into a pipe by bombarding fluid in the pipe with neutron pulses. The fluid in the pipe is activated and subsequently transported and mixed with the flow. Gamma radiation emitted from the activity is measured with one or two detectors downstream from the activation point. The time-resolved signal from the detectors is used to calculate the average velocity of the water flow. Due to the short distance between the neutron generator and the pipe the activity in the pipe becomes highly inhomogeneous. The transport and mixing of the activity were simulated using colour which was injected into the flow. It was found that the inhomogeneous activity distribution must be taken into account if the...

  15. Renal blood flow after selective injection of different dosages of diatrizoate into the renal artery

    International Nuclear Information System (INIS)

    Burgener, F.A.; Fischer, H.W.; Weber, D.A.

    1975-01-01

    The characteristic biphasic renal haemodynamic response to diatrizoate injected into the renal artery was shown in the dog with the 133-xenon washout technique. A brief increase in renal blood flow (RBF) during the first ten seconds is followed by a more prolonged period of diminuished RBF. A dose of 4 ml. diatrizoate 60% resulted in the maximum RBF increase of 43% after ten seconds, but even 1 ml. diatrizoate raised the RBF 24%. The initial vasodilator effect of diatrizoate compares well in its extent with the most potent renal vasodilators. (orig.) [de

  16. A study of the methods for the production and confinement of high energy plasmas. [injection of dense plasma into long magnetic field

    Science.gov (United States)

    Cheng, D. Y.; Wang, P.

    1972-01-01

    The injection of dense plasmas into a B sub z long magnetic field from both ends of the field coil was investigated. Deflagration plasma guns and continuous flow Z-pinch are discussed along with the possibility of a continuous flow Z-pinch fusion reactor. The injection experiments are described with emphasis on the synchronization of the two plasma deflagration guns, the collision of the two plasma beams, and the determination of plasma density.

  17. Ion Imprinted Polymer for Preconcentration and Determination of Ultra-Trace Cadmium, Employing Flow Injection Analysis with Thermo Spray Flame Furnace Atomic Absorption Spectrometry.

    Science.gov (United States)

    do Lago, Ayla Campos; Marchioni, Camila; Mendes, Tássia Venga; Wisniewski, Célio; Fadini, Pedro Sergio; Luccas, Pedro Orival

    2016-11-01

    This work proposes a preconcentration method using an ion imprinted polymer (IIP) for determination of cadmium, in several samples, employing a mini-column filled with the polymer coupled into a flow injection analysis system with detection by thermospray flame furnace atomic absorption spectrometry (FIA-TS-FF-AAS). The polymer was synthesized via bulk using methacrylic acid and vinylimidazole as a functional monomer. For the FIA system initial assessment, the variables: pH, eluent concentration and buffer concentration were studied, employing a 23 full factorial design. To obtain the optimum values for each significant variable, a Doehlert matrix was employed. After the optimization conditions as: pH 5.8, eluent (HNO3) concentration of 0.48 mol L -1 and buffer concentration of 0.01 mol L -1 , were adopted. The proposed method showed a linear response in the range of 0.081-10.0 μg L -1 , limits detection and quantification of 0.024 and 0.081 μg L -1 , respectively; preconcentration factor of 165, consumptive index of 0.06 mL, concentration efficiency 132 min -1 , and frequency of readings equal to 26 readings h -1 The accuracy was checked by analysis of certified reference materials for trace metals and recovery tests. The obtained results were in agreement with 95% confidence level (t-test). The method was adequate to apply in samples of: jewelry (earrings) (2.38 ± 0.28 μg kg -1 ), black tea (1.09 ± 0.15 μg kg -1 ), green tea (3.85 ± 0.13 μg kg -1 ), cigarette tobacco (38.27 ± 0.22 μg kg -1 ), and hair (0.35 ± 0.02 μg kg -1 ). © The Author(s) 2016.

  18. Time varying determinants of bond flows to emerging markets

    Directory of Open Access Journals (Sweden)

    Yasemin Erduman

    2016-06-01

    Full Text Available This paper investigates the time varying nature of the determinants of bond flows with a focus on the global financial crisis period. We estimate a time varying regression model using Bayesian estimation methods, where the posterior distribution is approximated by Gibbs sampling algorithm. Our findings suggest that the interest rate differential is the most significant pull factor of portfolio bond flows, along with the inflation rate, while the growth rate does not play a significant role. Among the push factors, global liquidity is the most important driver of bond flows. It matters the most, when unconventional monetary easing policies were first announced; and its importance as a determinant of portfolio bond flows decreases over time, starting with the Eurozone crisis, and diminishes with the tapering talk. Global risk appetite and the risk perception towards the emerging countries also have relatively small and stable significant effects on bond flows.

  19. Flow Injection Analysis with Electrochemical Detection for Rapid Identification of Platinum-Based Cytostatics and Platinum Chlorides in Water

    Directory of Open Access Journals (Sweden)

    Marketa Kominkova

    2014-02-01

    Full Text Available Platinum-based cytostatics, such as cisplatin, carboplatin or oxaliplatin are widely used agents in the treatment of various types of tumors. Large amounts of these drugs are excreted through the urine of patients into wastewaters in unmetabolised forms. This phenomenon leads to increased amounts of platinum ions in the water environment. The impacts of these pollutants on the water ecosystem are not sufficiently investigated as well as their content in water sources. In order to facilitate the detection of various types of platinum, we have developed a new, rapid, screening flow injection analysis method with electrochemical detection (FIA-ED. Our method, based on monitoring of the changes in electrochemical behavior of analytes, maintained by various pH buffers (Britton-Robinson and phosphate buffer and potential changes (1,000, 1,100 and 1,200 mV offers rapid and cheap selective determination of platinum-based cytostatics and platinum chlorides, which can also be present as contaminants in water environments.

  20. Investigation the effects of injection pressure and compressibility and nozzle entry in diesel injector nozzle’s flow

    Directory of Open Access Journals (Sweden)

    Seyed mohammadjavad Zeidi

    2015-04-01

    Full Text Available Investigating nozzle’s orifice flow is challenging both experimentally and theoretically. This paper focuses on simulating flow inside diesel injector nozzle via Ansys fluent v15. Validation is performed with experimental results from Winkhofler et al (2001. Several important parameters such as mass flow rate, velocity profiles and pressure profiles are used for this validation. Results include the effects of contraction inside nozzle’s orifice, effect of compressibility; effect of injection pressures and several orifice entries are also simulated in this study. For considering the effect of compressibility a user defined function used in this simulation. Cavitation model which is used in this simulation is Singhal et al. cavitation model. Presto discretization method is used for Pressure equation and second upwind discretization method is used for Momentum equation. Converging Singhal et al. cavitation model is very challenging and it needs several efforts and simulations.

  1. Radiometric detection in flow-injection analysis; Radiometric flow-injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Myint, U; Han, B; Myoe, K M; Kywe, A; Thida, [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Braatislava (Slovakia). Dept. of Environmental Science

    1994-05-17

    A single line system with a detector of radioactivity was used for the determination of [sup 60]Co. In the determination, no additional chemistry is involved and limited dispersion is desirable. For this application, the FIA system is used only as a transport system for the sample up to the detector. (author) 7 refs.; 4 figs.

  2. The determination of hepatic blood flow in the rat using Xenon-133

    International Nuclear Information System (INIS)

    Smith, A.; Clarke, M.B.

    1976-01-01

    The measurement of hepatic blood flow in rats undergoing surgical trauma using different anaesthetic techniques has been carried out using the 133 Xe clearance method. Injection into the hepatic artery is followed by monitoring of the liver radioactivity. The complex clearance curves have been analysed using a computer. Details of the surgical technique and the care of the animal while undergoing examination are given. The physiological basis for the clearance curves observed is analysed and a survey of the various parameters which may produce changes in clearance rates is made. Comparison with other investigations show that rat liver blood flows obtained using the 133 Xe clearance method are consistent with others using non-radioactive techniques; because of its simplicity and ease of repetition, the Xenon method is recommended as a way of evaluating drug effects on hepatic blood flow in experimental animals. (author)

  3. A fully automated effervescence assisted dispersive liquid–liquid microextraction based on a stepwise injection system. Determination of antipyrine in saliva samples

    Energy Technology Data Exchange (ETDEWEB)

    Medinskaia, Kseniia; Vakh, Christina; Aseeva, Darina [Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg (Russian Federation); Andruch, Vasil, E-mail: vasil.andruch@upjs.sk [Department of Analytical Chemistry, University of P.J. Šafárik, SK-04154 Košice (Slovakia); Moskvin, Leonid [Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg (Russian Federation); Bulatov, Andrey, E-mail: bulatov_andrey@mail.ru [Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg (Russian Federation)

    2016-01-01

    A first attempt to automate the effervescence assisted dispersive liquid–liquid microextraction (EA-DLLME) has been reported. The method is based on the aspiration of a sample and all required aqueous reagents into the stepwise injection analysis (SWIA) manifold, followed by simultaneous counterflow injection of the extraction solvent (dichloromethane), the mixture of the effervescence agent (0.5 mol L{sup −1} Na{sub 2}CO{sub 3}) and the proton donor solution (1 mol L{sup −1} CH{sub 3}COOH). Formation of carbon dioxide microbubbles generated in situ leads to the dispersion of the extraction solvent in the whole aqueous sample and extraction of the analyte into organic phase. Unlike the conventional DLLME, in the case of EA-DLLME, the addition of dispersive solvent, as well as, time consuming centrifugation step for disruption of the cloudy state is avoided. The phase separation was achieved by gentle bubbling of nitrogen stream (2 mL min{sup −1} during 2 min). The performance of the suggested approach is demonstrated by determination of antipyrine in saliva samples. The procedure is based on the derivatization of antipyrine by nitrite-ion followed by EA-DLLME of 4-nitrosoantipyrine and subsequent UV–Vis detection using SWIA manifold. The absorbance of the yellow-colored extract at the wavelength of 345 nm obeys Beer's law in the range of 1.5–100 µmol L{sup −1} of antipyrine in saliva. The LOD, calculated from a blank test based on 3σ, was 0.5 µmol L{sup −1}. - Highlights: • First attempt to automate the effervescence assisted dispersive liquid–liquid microextraction. • Automation based on Stepwise injection analysis manifold in flow batch system. • Counterflow injection of extraction solvent and the effervescence agent. • Phase separation performed by gentle bubbling of nitrogen. • Application for the determination of antipyrine in saliva samples.

  4. A fully automated effervescence assisted dispersive liquid–liquid microextraction based on a stepwise injection system. Determination of antipyrine in saliva samples

    International Nuclear Information System (INIS)

    Medinskaia, Kseniia; Vakh, Christina; Aseeva, Darina; Andruch, Vasil; Moskvin, Leonid; Bulatov, Andrey

    2016-01-01

    A first attempt to automate the effervescence assisted dispersive liquid–liquid microextraction (EA-DLLME) has been reported. The method is based on the aspiration of a sample and all required aqueous reagents into the stepwise injection analysis (SWIA) manifold, followed by simultaneous counterflow injection of the extraction solvent (dichloromethane), the mixture of the effervescence agent (0.5 mol L"−"1 Na_2CO_3) and the proton donor solution (1 mol L"−"1 CH_3COOH). Formation of carbon dioxide microbubbles generated in situ leads to the dispersion of the extraction solvent in the whole aqueous sample and extraction of the analyte into organic phase. Unlike the conventional DLLME, in the case of EA-DLLME, the addition of dispersive solvent, as well as, time consuming centrifugation step for disruption of the cloudy state is avoided. The phase separation was achieved by gentle bubbling of nitrogen stream (2 mL min"−"1 during 2 min). The performance of the suggested approach is demonstrated by determination of antipyrine in saliva samples. The procedure is based on the derivatization of antipyrine by nitrite-ion followed by EA-DLLME of 4-nitrosoantipyrine and subsequent UV–Vis detection using SWIA manifold. The absorbance of the yellow-colored extract at the wavelength of 345 nm obeys Beer's law in the range of 1.5–100 µmol L"−"1 of antipyrine in saliva. The LOD, calculated from a blank test based on 3σ, was 0.5 µmol L"−"1. - Highlights: • First attempt to automate the effervescence assisted dispersive liquid–liquid microextraction. • Automation based on Stepwise injection analysis manifold in flow batch system. • Counterflow injection of extraction solvent and the effervescence agent. • Phase separation performed by gentle bubbling of nitrogen. • Application for the determination of antipyrine in saliva samples.

  5. Electrochemical study and flow injection analysis of paracetamol in pharmaceutical formulations based on screen-printed electrodes and carbon nanotubes

    International Nuclear Information System (INIS)

    Fanjul-Bolado, Pablo; Lamas-Ardisana, Pedro Jose; Hernandez-Santos, David; Costa-Garcia, Agustin

    2009-01-01

    Acetaminophenol or paracetamol is one of the most commonly used analgesics in pharmaceutical formulations. Acetaminophen is electroactive and voltammetric mechanistic studies for the electrode processes of the acetaminophenol/N-acetyl-p-quinoneimine redox system are presented. Carbon nanotubes modified screen-printed electrodes with enhanced electron transfer properties are used for the study of the electrochemical-chemical oxidation mechanism of paracetamol at pH 2.0. Quantitative analysis of paracetamol by using its oxidation process (in a Britton-Robinson buffer solution pH 10.0) at +0.20 V (vs. an Ag pseudoreference electrode) on an untreated screen-printed carbon electrode (SPCE) was carried out. Thus, a cyclic voltammetric based reproducible determination of acetaminophen (R.S.D., 2.2%) in the range 2.5 x 10 -6 M to 1 x 10 -3 M, was obtained. However, when SPCEs are used as amperometric detectors coupled to a flow injection analysis (FIA) system, the detection limit achieved for paracetamol was 1 x 10 -7 M, one order of magnitude lower than that obtained by voltammetric analysis. The repeatability of the amperometric detection with the same SPCE is 2% for 15 successive injections of 10 -5 M acetaminophen and do not present any memory effect. Finally, the applicability of using screen-printed carbon electrodes for the electrochemical detection of paracetamol (i.e. for quality control analysis) was demonstrated by using two commercial pharmaceutical products.

  6. Determinants of virtual water flows in the Mediterranean.

    Science.gov (United States)

    Fracasso, Andrea; Sartori, Martina; Schiavo, Stefano

    2016-02-01

    The aim of the paper is to investigate the main determinants of the bilateral virtual water (water used in the production of a commodity or service) flows associated with international trade in agricultural goods across the Mediterranean basin. We consider the bilateral gross flows of virtual water in the area and study what export-specific and import-specific factors are significantly associated with virtual water flows. We follow a sequential approach. Through a gravity model of trade, we obtain a "refined" version of the variable we aim to explain, one that is free of the amount of flows due to pair-specific factors affecting bilateral trade flows and that fully reflects the impact of country-specific determinants of virtual water trade. A number of country-specific potential explanatory variables, ranging from water endowments to trade barriers, from per capita GDP to irrigation prices, is presented and tested. To identify the variables that help to explain the bilateral flows of virtual water, we adopt a model selection procedure based on model averaging. Our findings confirm one of the main controversial results in the literature: larger water endowments do not necessarily lead to a larger 'export' of virtual water, as one could expect. We also find some evidence that higher water irrigation prices reduce (increase) virtual water 'exports' ('imports'). Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Amperometric Determination of Sulfite by Gas Diffusion- Sequential Injection with Boron-Doped Diamond Electrode

    Directory of Open Access Journals (Sweden)

    Orawon Chailapakul

    2008-03-01

    Full Text Available A gas diffusion sequential injection system with amperometric detection using aboron-doped diamond electrode was developed for the determination of sulfite. A gasdiffusion unit (GDU was used to prevent interference from sample matrices for theelectrochemical measurement. The sample was mixed with an acid solution to generategaseous sulfur dioxide prior to its passage through the donor channel of the GDU. Thesulfur dioxide diffused through the PTFE hydrophobic membrane into a carrier solution of 0.1 M phosphate buffer (pH 8/0.1% sodium dodecyl sulfate in the acceptor channel of theGDU and turned to sulfite. Then the sulfite was carried to the electrochemical flow cell anddetected directly by amperometry using the boron-doped diamond electrode at 0.95 V(versus Ag/AgCl. Sodium dodecyl sulfate was added to the carrier solution to preventelectrode fouling. This method was applicable in the concentration range of 0.2-20 mgSO32−/L and a detection limit (S/N = 3 of 0.05 mg SO32−/L was achieved. This method wassuccessfully applied to the determination of sulfite in wines and the analytical resultsagreed well with those obtained by iodimetric titration. The relative standard deviations forthe analysis of sulfite in wines were in the range of 1.0-4.1 %. The sampling frequency was65 h−1.

  8. The Riemann Solution for the Injection of Steam and Nitrogen in a Porous Medium

    NARCIS (Netherlands)

    Lambert, W.; Marchesin, D.; Bruining, J.

    2009-01-01

    We solve the model for the flow of nitrogen, vapor, and water in a porous medium, neglecting compressibility, heat conductivity, and capillary effects. Our choice of injection conditions is determined by the application to clean up polluted sites. We study all mathematical structures, such as

  9. Determination of Flow Resistance Coefficient for Vegetation in Open Channel: Laboratory study

    Science.gov (United States)

    Aliza Ahmad, Noor; Ali, ZarinaMd; Arish, Nur Aini Mohd; Munirah Mat Daud, Azra; Fatin Amirah Alias, Nur

    2018-04-01

    This study focused on determination of flow resistances coefficient for grass in an open channel. Laboratory works were conducted to examine the effects of varying of roughness elements on the flume to determine flow resistance coefficient and also to determine the optimum flow resistance with five different flow rate, Q. Laboratory study with two type of vegetation which are Cow Grass and Pearl Grass were implementing to the bed of a flume. The roughness coefficient, n value is determine using Manning’s equation while Soil Conservation Services (SCS) method was used to determine the surface resistance. From the experiment, the flow resistance coefficient for Cow Grass in range 0.0008 - 0.0039 while Pearl Grass value for the flow resistance coefficient are in between 0.0013 - 0.0054. As a conclusion the vegetation roughness value in open channel are depends on density, distribution type of vegetation used and physical characteristic of the vegetation itself

  10. Determining FDI Flows into Scandinavia

    DEFF Research Database (Denmark)

    Kottaridi, Constantina; Bernhard Nielsen, Bo

    2003-01-01

    AbstractIn a recent global competitiveness report by the IMF, the four Nordic countries all ranked in top ten, attesting to the region?s growing attractiveness as a host location for MNCs. This paper investigates the driving forces determining foreign direct investment flows into Scandinavia. We...... for the changing pattern of international production indicating strategic needs for MNCs to acquire assets and technology that are specific to particular locations....

  11. Void fraction and flow regime determination by optical probe for boiling two-phase flow in a tube subchannel

    International Nuclear Information System (INIS)

    Cheng Huiping; Wu Hongtao; Ba Changxi; Yan Xiaoming; Huang Suyi

    1995-12-01

    In view of the need to determine void fraction and flow regime of vapor-liquid two-phase flow in the steam generator test model, domestic made optical probe was applied on a small-scale freon two-phase flow test rig. Optical probe signals were collected at a sampling rate up to 500 Hz and converted into digital form. Both the time signal, and the amplitude probability density function and FFT spectrum function calculated thereof were analysed in the time and frequency domains respectively. The threshold characterizing vapor or liquid contact with the probe tip was determined from the air-water two-phase flow pressure drop test results. Then, the boiling freon two-phase flow void fraction was determined by single threshold method, and compared with numerical heat transfer computation. Typical patterns which were revealed by the above-mentioned time signal and the functions were found corresponding to distinct flow regimes, as corroborated by visual observation. The experiment shows that the optical probe was a promising technique for two-phase flow void fraction measurement and flow regime identification (3 refs., 15 figs., 1 tab.)

  12. Dispersion in cylindrical channels on the laminar flow at low Fourier numbers.

    Science.gov (United States)

    Kucza, Witold; Dąbrowa, Juliusz; Nawara, Katarzyna

    2015-06-30

    A numerical solution of the uniform dispersion model in cylindrical channels at low Fourier numbers is presented. The presented setup allowed to eliminate experimental non-idealities interfering the laminar flow. Double-humped responses measured in a flow injection system with impedance detection agreed with those predicted by theory. Simulated concentration profiles as well as flow injection analysis (FIA) responses show the predictive and descriptive power of the numerical approach. A strong dependence of peak shapes on Fourier numbers, at its low values, makes the approach suitable for determination of diffusion coefficients. In the work, the uniform dispersion model coupled with the Levenberg-Marquardt method of optimization allowed to determine the salt diffusion coefficient for KCl, NaCl, KMnO4 and CuSO4 in water. The determined values (1.83, 1.53, 1.57 and 0.90)×10(-9)m(2)s(-1), respectively, agree well with the literature data. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Determination of averaged axisymmetric flow surfaces according to results obtained by numerical simulation of flow in turbomachinery

    Directory of Open Access Journals (Sweden)

    Bogdanović-Jovanović Jasmina B.

    2012-01-01

    Full Text Available In the increasing need for energy saving worldwide, the designing process of turbomachinery, as an essential part of thermal and hydroenergy systems, goes in the direction of enlarging efficiency. Therefore, the optimization of turbomachinery designing strongly affects the energy efficiency of the entire system. In the designing process of turbomachinery blade profiling, the model of axisymmetric fluid flows is commonly used in technical practice, even though this model suits only the profile cascades with infinite number of infinitely thin blades. The actual flow in turbomachinery profile cascades is not axisymmetric, and it can be fictively derived into the axisymmetric flow by averaging flow parameters in the blade passages according to the circular coordinate. Using numerical simulations of flow in turbomachinery runners, its operating parameters can be preliminarily determined. Furthermore, using the numerically obtained flow parameters in the blade passages, averaged axisymmetric flow surfaces in blade profile cascades can also be determined. The method of determination of averaged flow parameters and averaged meridian streamlines is presented in this paper, using the integral continuity equation for averaged flow parameters. With thus obtained results, every designer can be able to compare the obtained averaged flow surfaces with axisymmetric flow surfaces, as well as the specific work of elementary stages, which are used in the procedure of blade designing. Numerical simulations of flow in an exemplary axial flow pump, used as a part of the thermal power plant cooling system, were performed using Ansys CFX. [Projekat Ministarstva nauke Republike Srbije, br. TR33040: Revitalization of existing and designing new micro and mini hydropower plants (from 100 kW to 1000 kW in the territory of South and Southeast Serbia

  14. Viscous hydrophilic injection matrices for serial crystallography

    Directory of Open Access Journals (Sweden)

    Gabriela Kovácsová

    2017-07-01

    Full Text Available Serial (femtosecond crystallography at synchrotron and X-ray free-electron laser (XFEL sources distributes the absorbed radiation dose over all crystals used for data collection and therefore allows measurement of radiation damage prone systems, including the use of microcrystals for room-temperature measurements. Serial crystallography relies on fast and efficient exchange of crystals upon X-ray exposure, which can be achieved using a variety of methods, including various injection techniques. The latter vary significantly in their flow rates – gas dynamic virtual nozzle based injectors provide very thin fast-flowing jets, whereas high-viscosity extrusion injectors produce much thicker streams with flow rates two to three orders of magnitude lower. High-viscosity extrusion results in much lower sample consumption, as its sample delivery speed is commensurate both with typical XFEL repetition rates and with data acquisition rates at synchrotron sources. An obvious viscous injection medium is lipidic cubic phase (LCP as it is used for in meso membrane protein crystallization. However, LCP has limited compatibility with many crystallization conditions. While a few other viscous media have been described in the literature, there is an ongoing need to identify additional injection media for crystal embedding. Critical attributes are reliable injection properties and a broad chemical compatibility to accommodate samples as heterogeneous and sensitive as protein crystals. Here, the use of two novel hydrogels as viscous injection matrices is described, namely sodium carboxymethyl cellulose and the thermo-reversible block polymer Pluronic F-127. Both are compatible with various crystallization conditions and yield acceptable X-ray background. The stability and velocity of the extruded stream were also analysed and the dependence of the stream velocity on the flow rate was measured. In contrast with previously characterized injection media, both new

  15. Photometric flow injection determination of phosphate on a PDMS microchip using an optical detection system assembled with an organic light emitting diode and an organic photodiode.

    Science.gov (United States)

    Liu, Rong; Ishimatsu, Ryoichi; Yahiro, Masayuki; Adachi, Chihaya; Nakano, Koji; Imato, Toshihiko

    2015-01-01

    and a good linear relationship between the concentration and absorbance was observed in the concentration range 0-0.2 ppm, with a detection limit (S/N=3) of 0.02 ppm. The assembled photometric detector was also applied to the determination of phosphate by the flow injection of river water samples using the reagent solution containing MG and molybdenum ammonium in sulfuric acid. A good recovery (97-99%) for the river water samples, which had been spiked with the standard 0.08 ppm, with an RSD of ca 5% (n=5) was obtained using the constructed system. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Plasma jet source parameter optimisation and experiments on injection into Globus-M spherical tokamak

    International Nuclear Information System (INIS)

    Gusev, V.K.; Petrov, Yu.V.; Sakharov, N.V.; Semenov, A.A.; Voronin, A.V.

    2005-01-01

    Results of theoretical and experimental research on the plasma sources and injection of plasma and gas jet produced by the modified source into tokamak Globus-M are presented. An experimental test stand was developed for investigation of intense plasma jet generation. Optimisation of pulsed coaxial accelerator parameters by means of analytical calculations is performed with the aim of achieving the highest flow velocity at limited coaxial electrode length and discharge current. The optimal parameters of power supply to generate a plasma jet with minimal impurity contamination and maximum flow velocity were determined. A comparison of experimental and calculation results is made. Plasma jet parameters are measured, such as: impurity species content, pressure distribution across the jet, flow velocity, plasma density, etc. Experiments on the interaction of a higher kinetic energy plasma jet with the magnetic field and plasma of the Globus-M tokamak were performed. Experimental results on plasma and gas jet injection into different Globus-M discharge phases are presented and discussed. Results are presented on the investigation of plasma jet injection as the source for discharge breakdown, plasma current startup and initial density rise. (author)

  17. Porous media heat transfer for injection molding

    Science.gov (United States)

    Beer, Neil Reginald

    2016-05-31

    The cooling of injection molded plastic is targeted. Coolant flows into a porous medium disposed within an injection molding component via a porous medium inlet. The porous medium is thermally coupled to a mold cavity configured to receive injected liquid plastic. The porous medium beneficially allows for an increased rate of heat transfer from the injected liquid plastic to the coolant and provides additional structural support over a hollow cooling well. When the temperature of the injected liquid plastic falls below a solidifying temperature threshold, the molded component is ejected and collected.

  18. A comparison of two nuclear-medical techniques for effective renal plasma flow determination in rabbits: Radiation controlled infusion-pump and whole-body measurement according to Oberhausen

    International Nuclear Information System (INIS)

    Mayer-Wehrstein, R.

    1981-01-01

    Two nuclear techniques were investigated for determination of the effective renal plasma flow with J-131-Hippuran in rabbits: whole-body measurement according to Oberhausen and clearance determination with a radiation controlled feed back infusion pump. In the first method the clearance determination follows after a single injection of the testing substance in the decreasing phase of the blood level, in the second method a constant blood level of the testing substance is maintained. A technique was developed for the determination of the blood-tissue ratio by considering the values determined by the constant blood level. This way the exact clearance values were computet for the decreasing plasma level. Nineteen clearance determinations were performed in rabbits altogether. (orig.) [de

  19. Experimental feasibility study of radial injection cooling of three-pad radial air foil bearings

    Science.gov (United States)

    Shrestha, Suman K.

    Air foil bearings use ambient air as a lubricant allowing environment-friendly operation. When they are designed, installed, and operated properly, air foil bearings are very cost effective and reliable solution to oil-free turbomachinery. Because air is used as a lubricant, there are no mechanical contacts between the rotor and bearings and when the rotor is lifted off the bearing, near frictionless quiet operation is possible. However, due to the high speed operation, thermal management is one of the very important design factors to consider. Most widely accepted practice of the cooling method is axial cooling, which uses cooling air passing through heat exchange channels formed underneath the bearing pad. Advantage is no hardware modification to implement the axial cooling because elastic foundation structure of foil bearing serves as a heat exchange channels. Disadvantage is axial temperature gradient on the journal shaft and bearing. This work presents the experimental feasibility study of alternative cooling method using radial injection of cooling air directly on the rotor shaft. The injection speeds, number of nozzles, location of nozzles, total air flow rate are important factors determining the effectiveness of the radial injection cooling method. Effectiveness of the radial injection cooling was compared with traditional axial cooling method. A previously constructed test rig was modified to accommodate a new motor with higher torque and radial injection cooling. The radial injection cooling utilizes the direct air injection to the inlet region of air film from three locations at 120° from one another with each location having three axially separated holes. In axial cooling, a certain axial pressure gradient is applied across the bearing to induce axial cooling air through bump foil channels. For the comparison of the two methods, the same amount of cooling air flow rate was used for both axial cooling and radial injection. Cooling air flow rate was

  20. Performance Evaluation of Monolith Based Immobilized Acetylcholinesterase Flow-Through Reactor for Copper(II Determination with Spectrophotometric Detection

    Directory of Open Access Journals (Sweden)

    Parawee Rattanakit

    2014-01-01

    Full Text Available A monolith based immobilized acetylcholinesterase (AChE flow-through reactor has been developed for the determination of copper(II using flow injection spectrophotometric system. The bioreactor was prepared inside a microcapillary column by in situ polymerization of butyl methacrylate, ethylene dimethacrylate, and 2,2-dimethoxy-1,2-diphynyletane-1-one in the presence of 1-decanol, followed by vinyl azlactone functionalization and AChE immobilization. The behavior of AChE before and after being immobilized on the monolith was evaluated by kinetic parameters from Lineweaver and Burk equation. The detection was based on measuring inhibition effect on the enzymatic activity of AChE by copper(II using Ellman’s reaction with spectrophotometric detection at 410 nm. The linear range of the calibration graph was obtained over the range of 0.02–3.00 mg L−1. The detection limit, defined as 10% inhibition (I10, was found to be 0.04 mg L−1. The repeatability was 3.35 % (n=5 for 1.00 mg L−1 of copper(II. The proposed method was applied to the determination of copper(II in natural water samples with sampling rate of 4 h−1.

  1. Injection of nano-particles in mitigating flow accelerated corrosion (FAC) damage in the secondary system of nuclear power plants (NPPs)

    International Nuclear Information System (INIS)

    Lim, Dong Seok; Ku, Hee Kwon; Cho, Jae Seon

    2015-01-01

    NPPs produces electric energy through phase transition of water. According to this, a piping, which is flow path, integrity is essential for safety functions. Erosion, FAC and fittings are corrosion failure mechanism by increasing service life. Especially, there are 10-kilometers of piping in secondary systems. It needs to estimate FAC and apply periodic management. Iron oxides produced by FAC cause power reduction and Loss Of Coolant Accident (LOCA) will be occurred through the continued piping wall thinning. In this study, corrosion rate of pipe materials with carbon steel(SA106.Gr.B) and low-alloy steel (SA335.P22) was evaluated for pipe configuration and dissolved oxygen concentration on 150 °C, pH 9.5∼10.0 and flow velocity of 5m/s. Temperature of 150°C is well known that causes high FAC rate and pH consider a NPPs in-service condition. Further corrosion rate test was performed to develop FAC reduction technology through Pt-nanoparticle injection. In this study, corrosion rate is evaluated by weight depletion method. The results of material impact assessment show that corrosion rate of carbon steel is more higher than that of low-alloy steel because of Cr content. And also, the results of pipe configuration test show that case with 90° elbow had maximum wall thinning than with 180° horizontal pipe. The dissolved oxygen concentration test shows that low oxygen condition, ≤5 ppb, had high corrosion rate compared to normal condition and the corrosion rate decreased 50% at Pt-nanoparticle injection test on maximum corrosion rate condition compared to maximum wall thinning condition without Pt-nanoparticle injection. In this study, samples provided by each test case had analyzed through SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy). Behavior evaluation for oxide film was performed and Electrochemical corrosion potential (ECP) was measured for electrochemistry evaluation. To apply Pt-nanoparticle injection technology on nuclear

  2. A similar solution for an unsteady free convection flow past an impulsively started vertical plate with mass transfer and suction or injection

    International Nuclear Information System (INIS)

    Sattar, M.A.

    1990-12-01

    A similar solution for the flow past a vertical plate started impulsively in its own plane in a viscous incompressible fluid is presented on taking into account the effects of variable suction and/or injection and mass transfer. To solve the momentum, energy and concentration equations, a time dependent length scale is introduced, which leads to the driving parameters γ(=G r /R σ 2 ) and γ*(=G r */R σ 2 ), where G r and G r * are respectively the Grashof and modified Grashof numbers while R σ is the Reynolds number. The resulting locally similar momentum equation is then solved by the method of superposition. The effects of the parameters and that of suction/injection on the flow and on the wall shear-stress of the plate are shown graphically for different values of Schmidt number and transpiration parameter. (author). 24 refs, 11 figs

  3. Injection of Syngeneic Murine Melanoma Cells to Determine Their Metastatic Potential in the Lungs.

    Science.gov (United States)

    Timmons, Joshua J; Cohessy, Sean; Wong, Eric T

    2016-05-24

    Approximately 90% of human cancer deaths are linked to metastasis. Despite the prevalence and relative harm of metastasis, therapeutics for treatment or prevention are lacking. We report a method for the establishment of pulmonary metastases in mice, useful for the study of this phenomenon. Tail vein injection of B57BL/6J mice with B16-BL6 is among the most used models for melanoma metastases. Some of the circulating tumor cells establish themselves in the lungs of the mouse, creating "experimental" metastatic foci. With this model it is possible to measure the relative effects of therapeutic agents on the development of cancer metastasis. The difference in enumerated lung foci between treated and untreated mice indicates the efficacy of metastases neutralization. However, prior to the investigation of a therapeutic agent, it is necessary to determine an optimal number of injected B16-BL6 cells for the quantitative analysis of metastatic foci. Injection of too many cells may result in an overabundance of metastatic foci, impairing proper quantification and overwhelming the effects of anti-cancer therapies, while injection of too few cells will hinder the comparison between treated and controls.

  4. 77 FR 41411 - Determination That TOPOTECAN INJECTION (Topotecan Hydrochloride) 1 Milligram (Base)/1 Milliliter...

    Science.gov (United States)

    2012-07-13

    ... marketing for reasons other than safety or effectiveness. ANDAs that refer to TOPOTECAN INJECTION (topotecan... or Effectiveness AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and... reasons of safety or effectiveness. This determination will allow FDA to approve abbreviated new drug...

  5. Analysis of large break loss of coolant accident with simultaneous injection into cold leg and hot leg

    International Nuclear Information System (INIS)

    Luo Bangqi

    1997-01-01

    When a large break loss of coolant accident occurs, the most part of the safety injection water injected into the cold leg by the safety injection system will flow through the channel between the pressure vessel and the barrel out of the break into the containment, only a little part of the safety injection water can flow into the reactor core. If the safety injection can inject into both the cold leg and the hot leg simultaneously, the safety injection water injected from the cold leg will flow into the core more easily, because the safety injection water injected from the hot leg will carry out more heat from the upper plenum and the core, so the upper plenum and the core is depressed. In addition, a small part of the safety injection water injected from the hot leg will flow down in the core after impinging the guide tubes in the upper plenum, so the core will get more safety injection water than only cold leg injection, and the core will be much safer

  6. Determinação turbidimétrica de dipirona em fluxo utilizando um reator contendo cloreto de prata imobilizado em resina poliéster Flow injection turbidimetric determination of dipyrone using a solid-phase reactor containing silver chloride immobilized in a polyester resin

    Directory of Open Access Journals (Sweden)

    Luiz H. Marcolino-Jr.

    2005-10-01

    Full Text Available A simple flow injection procedure was developed for determining dipyrone (1-phenyl-2,3-dimethyl-4-methylaminomethano-5-pyrazolone sodium, metamizol, analgin in pharmaceutical formulations. The determination is based on the reduction of Ag+ ions to Ag0 by dipyrone. A colloidal suspension of Ag0 produced was transported by carrier solution (0.01 mol L-1 NaOH and turbidimetrically detected at 425 nm. The analytical curve for dipyrone was linear in the range from 5.0 x 10-4 to 2.5 x 10-3 mol L-1 with a correlation coefficient of 0.9990. The detection limit was 1.3 x 10-4 mol L-1 (3sigmaB/slope. The relative standard deviation for ten successive measurements was 1.8% and an analytical frequency of 45 h-1 was obtained. The recovery values from three samples ranged from 96.0 to 102%.

  7. Photometric estimation of plutonium in product solutions and acid waste solutions using flow injection analysis technique

    International Nuclear Information System (INIS)

    Dhas, A.J.A.; Dharmapurikar, G.R.; Kumaraguru, K.; Vijayan, K.; Kapoor, S.C.; Ramanujam, A.

    1995-01-01

    Flow injection analysis technique is employed for the measurement of plutonium concentrations in product nitrate solutions by measuring the absorbance of Pu(III) at 565 nm and of Pu(IV) at 470 nm, using a Metrohm 662 photometer, with a pyrex glass tube of 2 nm (ID) inserted in the light path of the detector serving as a flow cell. The photometer detector never comes in contact with radioactive solution. In the case of acid waste solutions Pu is first purified by extraction chromatography with 2-ethyl hexyl hydrogen 2 ethyl hexyl phosphonate (KSM 17)- chromosorb and the Pu in the eluate in complexed with Arsenazo III followed by the measured of absorbance at 665 nm. Absorbance of reference solutions in the desired concentration ranges are measured to calibrate the system. The results obtained agree with the reference values within ±2.0%. (author). 3 refs., 1 tab

  8. Electrochemical study and flow injection analysis of paracetamol in pharmaceutical formulations based on screen-printed electrodes and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Fanjul-Bolado, Pablo [DropSens, S.L., Edificio Severo Ochoa, Campus El Cristo, 33006 Oviedo, Asturias (Spain); Lamas-Ardisana, Pedro Jose [Departamento de Quimica Fisica y Analitica, Universidad de Oviedo, Julian Claveria 8, 33006 Oviedo, Asturias (Spain); Hernandez-Santos, David [DropSens, S.L., Edificio Severo Ochoa, Campus El Cristo, 33006 Oviedo, Asturias (Spain); Costa-Garcia, Agustin, E-mail: costa@fq.uniovi.es [Departamento de Quimica Fisica y Analitica, Universidad de Oviedo, Julian Claveria 8, 33006 Oviedo, Asturias (Spain)

    2009-04-13

    Acetaminophenol or paracetamol is one of the most commonly used analgesics in pharmaceutical formulations. Acetaminophen is electroactive and voltammetric mechanistic studies for the electrode processes of the acetaminophenol/N-acetyl-p-quinoneimine redox system are presented. Carbon nanotubes modified screen-printed electrodes with enhanced electron transfer properties are used for the study of the electrochemical-chemical oxidation mechanism of paracetamol at pH 2.0. Quantitative analysis of paracetamol by using its oxidation process (in a Britton-Robinson buffer solution pH 10.0) at +0.20 V (vs. an Ag pseudoreference electrode) on an untreated screen-printed carbon electrode (SPCE) was carried out. Thus, a cyclic voltammetric based reproducible determination of acetaminophen (R.S.D., 2.2%) in the range 2.5 x 10{sup -6} M to 1 x 10{sup -3} M, was obtained. However, when SPCEs are used as amperometric detectors coupled to a flow injection analysis (FIA) system, the detection limit achieved for paracetamol was 1 x 10{sup -7} M, one order of magnitude lower than that obtained by voltammetric analysis. The repeatability of the amperometric detection with the same SPCE is 2% for 15 successive injections of 10{sup -5} M acetaminophen and do not present any memory effect. Finally, the applicability of using screen-printed carbon electrodes for the electrochemical detection of paracetamol (i.e. for quality control analysis) was demonstrated by using two commercial pharmaceutical products.

  9. Large scale gas injection test (Lasgit): Results from two gas injection tests

    International Nuclear Information System (INIS)

    Cuss, R. J.; Harrington, J. F.; Noy, D. J.; Wikman, A.; Sellin, P.

    2011-01-01

    This paper describes the initial results from a large scale gas injection test (Lasgit) performed at the Aespoe Hard Rock Laboratory (Sweden)). Lasgit is a full-scale field-scale experiment based on the Swedish KBS-3V repository concept, examining the processes controlling gas and water flow in compact buffer bentonite. The first 2 years of the test focused on the artificial hydration of the bentonite buffer. This was followed by a programme of hydraulic and gas injection tests which ran from day 843 to 1110. A further period of artificial hydration occurred from day 1110 to 1385, followed by a more complex programme of gas injection testing which remains on going (day 1385+). After 2 years of hydration, hydraulic conductivity and specific storage values in the lower filter array were found to range from 9 x 10 -14 to 1.6 x 10 -13 m/s and 5.5 x 10 -5 to 4.4 x 10 -4 m -1 respectively, with the injection filter FL903 yielding values of 7.5 x 10 -14 m/s and 2.5 x 10 -5 m -1 . A second set of hydraulic measurements were performed over 1 year and a half later yielding similar values, in the range 7.8 x 10 -14 m/s and 1.3 x 10 -13 m/s. The hydraulic conductivity of FL903 had reduced slightly to 5.3 x 10 -14 m/s while specific storage had increased to 4.0 x 10 -5 m -1 . Both datasets agree with laboratory values performed on small-scale saturated samples. Two sets of gas injection tests were performed over a 3 year period. During the course of testing, gas entry pressure was found to increase from around 650 kPa to approximately 1.3 MPa, indicative of the maturation of the clay. The sequential reduction in volumetric flow rate and lack of correlation between the rate of gas inflow and the gas pressure gradient observed during constant pressure steps prior to major gas entry, is suggestive of a reduction in gas permeability of the buffer and indicates only limited quantities of gas can be injected into the clay without interacting with the continuum stress field. Major gas

  10. 76 FR 72950 - Determination That TAXOTERE (Docetaxel) Injection, 40 Milligrams/Milliliter Was Not Withdrawn...

    Science.gov (United States)

    2011-11-28

    ... marketing for reasons other than safety or effectiveness. ANDAs that refer to TAXOTERE (docetaxel) Injection... Reasons of Safety or Effectiveness AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The.../milliliter (mg/mL), was not withdrawn from sale for reasons of safety or effectiveness. This determination...

  11. Two-dimensional analysis of two-phase reacting flow in a firing direct-injection diesel engine

    Science.gov (United States)

    Nguyen, H. Lee

    1989-01-01

    The flow field, spray penetration, and combustion in two-stroke diesel engines are described. Fuel injection begins at 345 degrees after top dead center (ATDC) and n-dodecane is used as the liquid fuel. Arrhenius kinetics is used to calculate the reaction rate term in the quasi-global combustion model. When the temperature, fuel, and oxygen mass fraction are within suitable flammability limits, combustion begins spontaneously. No spark is necessary to ignite a localized high temperature region. Compression is sufficient to increase the gaseous phase temperature to a point where spontaneous chemical reactions occur. Results are described for a swirl angle of 22.5 degrees.

  12. Toward a high-throughput method for determining vicine and convicine levels in faba bean seeds using flow injection analysis combined with tandem mass spectrometry.

    Science.gov (United States)

    Purves, Randy W; Khazaei, Hamid; Vandenberg, Albert

    2018-08-01

    Although faba bean provides environmental and health benefits, vicine and convicine (v-c) limit its use as a source of vegetable protein. Crop improvement efforts to minimize v-c concentration require low-cost, rapid screening methods to distinguish between high and low v-c genotypes to accelerate development of new cultivars and to detect out-crossing events. To assist crop breeders, we developed a unique and rapid screening method that uses a 60 s instrumental analysis step to accurately distinguish between high and low v-c genotypes. The method involves flow injection analysis (FIA) coupled with tandem mass spectrometry (i.e., selective reaction monitoring, SRM). Using seeds with known v-c levels as calibrants, measured v-c levels were comparable with liquid chromatography (LC)-SRM results and the method was used to screen 370 faba bean genotypes. Widespread use of FIA-SRM will accelerate breeding of low v-c faba bean, thereby alleviating concerns about anti-nutritional effects of v-c in this crop. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Global Qualitative Flow-Path Modeling for Local State Determination in Simulation and Analysis

    Science.gov (United States)

    Malin, Jane T. (Inventor); Fleming, Land D. (Inventor)

    1998-01-01

    For qualitative modeling and analysis, a general qualitative abstraction of power transmission variables (flow and effort) for elements of flow paths includes information on resistance, net flow, permissible directions of flow, and qualitative potential is discussed. Each type of component model has flow-related variables and an associated internal flow map, connected into an overall flow network of the system. For storage devices, the implicit power transfer to the environment is represented by "virtual" circuits that include an environmental junction. A heterogeneous aggregation method simplifies the path structure. A method determines global flow-path changes during dynamic simulation and analysis, and identifies corresponding local flow state changes that are effects of global configuration changes. Flow-path determination is triggered by any change in a flow-related device variable in a simulation or analysis. Components (path elements) that may be affected are identified, and flow-related attributes favoring flow in the two possible directions are collected for each of them. Next, flow-related attributes are determined for each affected path element, based on possibly conflicting indications of flow direction. Spurious qualitative ambiguities are minimized by using relative magnitudes and permissible directions of flow, and by favoring flow sources over effort sources when comparing flow tendencies. The results are output to local flow states of affected components.

  14. Determinação espectrofotométrica de vitamina B2 (riboflavina em formulações farmacêuticas empregando sistema de análises por injeção em fluxo Spectrophotometric determination of vitamin B2 (riboflavin in pharmaceutical formulations using flow injection analysis

    Directory of Open Access Journals (Sweden)

    Clezio Aniceto

    2000-10-01

    Full Text Available A flow injection spectrophotometric procedure exploiting merging zones is proposed for determining vitamin B2 (riboflavin in pharmaceutical preparations. The determination is based on the red-colored complex formation between vitamin B2 and silver(I which was measured at 520 nm. Vitamin B2 was determined in four pharmaceutical preparations in the 1.0 to 50.0 mg L-1 concentration range, with a detection limit of 0.5 mg L-1. The recovery from three samples ranged from 98.0 to 104.0 %. The analytical frequency was 42 h-1 and r.s.d. were lower than 1% for solutions containing 10.0, 30.0 and 50.0 mg L-1 vitamin B2 (n= 10. The results obtained in commercial formulations using the FIA procedure were in good agreement with those obtained by using a conventional fluorimetric procedure (r=0.9998 and also with the label values (r= 0.9997.

  15. Optoelectronic iron detectors for pharmaceutical flow analysis.

    Science.gov (United States)

    Rybkowska, Natalia; Koncki, Robert; Strzelak, Kamil

    2017-10-25

    Compact flow-through optoelectronic detectors fabricated by pairing of light emitting diodes have been applied for development of economic flow analysis systems dedicated for iron ions determination. Three analytical methods with different chromogens selectively recognizing iron ions have been compared. Ferrozine and ferene S based methods offer higher sensitivity and slightly lower detection limits than method with 1,10-phenantroline, but narrower ranges of linear response. Each system allows detection of iron in micromolar range of concentration with comparable sample throughput (20 injections per hour). The developed flow analysis systems have been successfully applied for determination of iron in diet supplements. The utility of developed analytical systems for iron release studies from drug formulations has also been demonstrated. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Exploiting flow Injection and sequential injection schemes for trace metal determinations by electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    Determination of low or trace-level amounts of metals by electrothermal atomic absorption spectrometry (ETAAS) often requires the use of suitable preconcentration and/or separation procedures in order to attain the necessary sensitivity and selectivity. Such schemes are advantageously executed...... by superior performance and versatility. In fact, two approaches are conceivable: The analyte-loaded ion-exchange beads might either be transported directly into the graphite tube where they are pyrolized and the measurand is atomized and quantified; or the loaded beads can be eluted and the eluate forwarded...

  17. Hydrogen/oxygen injection stopping method for nuclear power plant and emergent hydrogen/oxygen injection device

    International Nuclear Information System (INIS)

    Ishida, Ryoichi; Ota, Masamoto; Takagi, Jun-ichi; Hirose, Yuki

    1998-01-01

    The present invention provides a device for suppressing increase of electroconductivity of reactor water during operation of a BWR type reactor, upon occurrence of reactor scram of the plant or upon stopping of hydrogen/oxygen injection due to emergent stoppage of an injection device so as not to deteriorate the integrity of a gas waste processing system upon occurrence of scram. Namely, when injection of hydrogen/oxygen is stopped during plant operation, the injection amount of hydrogen is reduced gradually. Subsequently, injection of hydrogen is stopped. With such procedures, the increase of electroconductivity of reactor water can be suppressed upon stoppage of hydrogen injection. When injection of hydrogen/oxygen is stopped upon shut down of the plant, the amount of hydrogen injection is changed depending on the change of the feedwater flow rate, and then the plant is shut down while keeping hydrogen concentration of feedwater to a predetermined value. With such procedures, increase of the reactor water electroconductivity can be suppressed upon stoppage of hydrogen injection. Upon emergent stoppage of the hydrogen/oxygen injection device, an emergent hydrogen/oxygen injection device is actuated to continue the injection of hydrogen/oxygen. With such procedures, elevation of reactor water electroconductivity can be suppressed. (I.S.)

  18. Effect of completion geometry and phasing on single-phase liquid flow behaviour in horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, H.; Sarica, C.; Brill, P. [Tulsa Unov., OK (United States)

    1998-12-31

    The effects of completion geometries and the phasing and density of injection openings in horizontal wells was studied. A total of 1,257 tests were conducted for no fluid injections, no main flow at the test section inlet, and with fluid injection for Reynolds numbers ranging from 4,000 to 60,000 and for influx to main flow rate ratios ranging from 1/5 to 1/2000. Results demonstrated the dramatic effects of completion geometry, phasing density, Reynolds number and main flow rate on the pressure behaviour and therefore on the production behaviour of the well. A general friction factor expression for horizontal wells with multiple injection openings was developed based on the conservation of mass and momentum and using a commercial Computational Fluid Dynamics (CFD) computer program to determine the length of the flow developing region in a horizontal well. A field example is presented to show the importance of using the proper friction factor correlation to calculate the pressure drop in a horizontal well. 32 refs., 4 tabs., 20 figs.

  19. Seasonal Variability in Regional Ice Flow Due to Meltwater Injection Into the Shear Margins of Jakobshavn Isbræ

    Science.gov (United States)

    Cavanagh, J. P.; Lampkin, D. J.; Moon, T.

    2017-12-01

    The impact of meltwater injection into the shear margins of Jakobshavn Isbræ via drainage from water-filled crevasses on ice flow is examined. We use Landsat-8 Operational Land Imager panchromatic, high-resolution imagery to monitor the spatiotemporal variability of seven water-filled crevasse ponds during the summers of 2013 to 2015. The timing of drainage from water-filled crevasses coincides with an increase of 2 to 20% in measured ice velocity beyond Jakobshavn Isbræ shear margins, which we define as extramarginal ice velocity. Some water-filled crevasse groups demonstrate multiple drainage events within a single melt season. Numerical simulations show that hydrologic shear weakening due to water-filled crevasse drainage can accelerate extramarginal flow by as much as 35% within 10 km of the margins and enhance mass flux through the shear margins by 12%. This work demonstrates a novel mechanism through which surface melt can influence regional ice flow.

  20. Tumor blood flow and systemic shunting in patients receiving intraarterial chemotherapy for head and neck cancer

    International Nuclear Information System (INIS)

    Wheeler, R.H.; Ziessman, H.A.; Medvec, B.R.; Juni, J.E.; Thrall, J.H.; Keyes, J.W.; Pitt, S.R.; Baker, S.R.

    1986-01-01

    Radionuclide techniques have been used to estimate the systemic shunt and to quantitate blood flow to the tumor and a reference normal tissue in nine patients undergoing intraarterial chemotherapy for head and neck cancer. The systemic shunt was calculated as the percentage of pulmonary trapping of intraarterially injected /sup 99m/Tc-labeled macroaggregated albumin. The mean systemic shunt in the 12 separate arteries studied was 23 +/- 13% (SE) (range 8-43%). Quantitative blood flow was determined from the slope of the washout curve of intraarterially injected 133 Xe. The mean tumor blood flow was 13.6 +/- 6.7 ml/100 g/min, while the mean blood flow to the scalp was 4.2 +/- 2.1 ml/100 g/min providing a mean tumor/normal tissue ratio of 3.9 +/- 2.7. An estimate of blood flow distribution was obtained by calculating the ratio of counts/pixel in the tumor mass versus the remainder of the head as determined by single photon emission computed tomography following an intraarterial injection of /sup 99m/Tc-labeled macroaggregated albumin. The mean ratio of tumor to normal tissue perfusion by this technique was 5.6 +/- 3.7. These techniques have allowed noninvasive determination of the blood flow parameters associated with intraarterial chemotherapy. At least part of the therapeutic advantage of regional chemotherapy in patients with head and neck cancer is due to a tumor/normal tissue blood flow ratio that favors drug delivery to the tumor contained within the infused volume

  1. Performance and emission studies on port injection of hydrogen with varied flow rates with Diesel as an ignition source

    International Nuclear Information System (INIS)

    Saravanan, N.; Nagarajan, G.

    2010-01-01

    Automobiles are one of the major sources of air pollution in the environment. In addition CO 2 emission, a product of complete combustion also has become a serious issue due to global warming effect. Hence the search for cleaner alternative fuels has become mandatory. Hydrogen is expected to be one of the most important fuels in the near future for solving the problems of air pollution and greenhouse gas problems (carbon dioxide), thereby protecting the environment. Hence in the present work, an experimental investigation has been carried out using hydrogen in the dual fuel mode in a Diesel engine system. In the study, a Diesel engine was converted into a dual fuel engine and hydrogen fuel was injected into the intake port while Diesel was injected directly inside the combustion chamber during the compression stroke. Diesel injected inside the combustion chamber will undergo combustion first which in-turn would ignite the hydrogen that will also assist the Diesel combustion. Using electronic control unit (ECU), the injection timings and injection durations were varied for hydrogen injection while for Diesel the injection timing was 23 o crank angle (CA) before injection top dead centre (BITDC). Based on the performance, combustion and emission characteristics, the optimized injection timing was found to be 5 o CA before gas exchange top dead centre (BGTDC) with injection duration of 30 o CA for hydrogen Diesel dual fuel operation. The optimum hydrogen flow rate was found to be 7.5 lpm. Results indicate that the brake thermal efficiency in hydrogen Diesel dual fuel operation increases by 15% compared to Diesel fuel at 75% load. The NO X emissions were higher by 1-2% in dual fuel operation at full load compared to Diesel. Smoke emissions are lower in the entire load spectra due to the absence of carbon in hydrogen fuel. The carbon monoxide (CO), carbon dioxide (CO 2 ) emissions were lesser in hydrogen Diesel dual fuel operation compared to Diesel. The use of hydrogen

  2. Performance and emission studies on port injection of hydrogen with varied flow rates with Diesel as an ignition source

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, N. [ERC Engines, Tata Motors, Pimpri, Pune (India); Nagarajan, G. [Internal Combustion Engineering Division, Department of Mechanical Engineering, College of Engineering, Guindy, Anna University, Chennai (India)

    2010-07-15

    Automobiles are one of the major sources of air pollution in the environment. In addition CO{sub 2} emission, a product of complete combustion also has become a serious issue due to global warming effect. Hence the search for cleaner alternative fuels has become mandatory. Hydrogen is expected to be one of the most important fuels in the near future for solving the problems of air pollution and greenhouse gas problems (carbon dioxide), thereby protecting the environment. Hence in the present work, an experimental investigation has been carried out using hydrogen in the dual fuel mode in a Diesel engine system. In the study, a Diesel engine was converted into a dual fuel engine and hydrogen fuel was injected into the intake port while Diesel was injected directly inside the combustion chamber during the compression stroke. Diesel injected inside the combustion chamber will undergo combustion first which in-turn would ignite the hydrogen that will also assist the Diesel combustion. Using electronic control unit (ECU), the injection timings and injection durations were varied for hydrogen injection while for Diesel the injection timing was 23 crank angle (CA) before injection top dead centre (BITDC). Based on the performance, combustion and emission characteristics, the optimized injection timing was found to be 5 CA before gas exchange top dead centre (BGTDC) with injection duration of 30 CA for hydrogen Diesel dual fuel operation. The optimum hydrogen flow rate was found to be 7.5 lpm. Results indicate that the brake thermal efficiency in hydrogen Diesel dual fuel operation increases by 15% compared to Diesel fuel at 75% load. The NO{sub X} emissions were higher by 1-2% in dual fuel operation at full load compared to Diesel. Smoke emissions are lower in the entire load spectra due to the absence of carbon in hydrogen fuel. The carbon monoxide (CO), carbon dioxide (CO{sub 2}) emissions were lesser in hydrogen Diesel dual fuel operation compared to Diesel. The use of

  3. Application of artificial radioactive tracers for groundwater flow

    International Nuclear Information System (INIS)

    Hamza, M.S.; Aly, A.I.M.; Swailem, F.M.; Nada, A.A.; Awad, M.A.

    1989-01-01

    In this work, the groundwater velocity was estimated by applying radioactive tracer techniques: the single well and the multiple well methods. In the first single well method, radioactive iodine-131 was injected in the well and the radioactivity was monitored with time. The groundwater flow was estimated as a function of the concentration dilution factor of the tracer taking into consideration the permeability of the filter screen and the aquifer. The second method (the multiple well technique) is based on direct measuring of the period of time the tracer needs to disperse from the injection well to one of receptor well arranged in a circle around the injection. The latter method was found to be more accurate and reliable and has also the advantage of determining the groundwater velocity and direction of flow as well. The limitations of the single well technique are discussed and a detailed comparison between single and multi-well techniques is given

  4. Application of hydrocyanic acid vapor generation via focused microwave radiation to the preparation of industrial effluent samples prior to free and total cyanide determinations by spectrophotometric flow injection analysis.

    Science.gov (United States)

    Quaresma, Maria Cristina Baptista; de Carvalho, Maria de Fátima Batista; Meirelles, Francis Assis; Santiago, Vânia Maria Junqueira; Santelli, Ricardo Erthal

    2007-02-01

    A sample preparation procedure for the quantitative determination of free and total cyanides in industrial effluents has been developed that involves hydrocyanic acid vapor generation via focused microwave radiation. Hydrocyanic acid vapor was generated from free cyanides using only 5 min of irradiation time (90 W power) and a purge time of 5 min. The HCN generated was absorbed into an accepting NaOH solution using very simple glassware apparatus that was appropriate for the microwave oven cavity. After that, the cyanide concentration was determined within 90 s using a well-known spectrophotometric flow injection analysis system. Total cyanide analysis required 15 min irradiation time (90 W power), as well as chemical conditions such as the presence of EDTA-acetate buffer solution or ascorbic acid, depending on the effluent to be analyzed (petroleum refinery or electroplating effluents, respectively). The detection limit was 0.018 mg CN l(-1) (quantification limit of 0.05 mg CN l(-1)), and the measured RSD was better than 8% for ten independent analyses of effluent samples (1.4 mg l(-1) cyanide). The accuracy of the procedure was assessed via analyte spiking (with free and complex cyanides) and by performing an independent sample analysis based on the standard methodology recommended by the APHA for comparison. The sample preparation procedure takes only 10 min for free and 20 min for total cyanide, making this procedure much faster than traditional methodologies (conventional heating and distillation), which are time-consuming (they require at least 1 h). Samples from oil (sour and stripping tower bottom waters) and electroplating effluents were analyzed successfully.

  5. The State Fiscal Policy: Determinants and Optimization of Financial Flows

    Directory of Open Access Journals (Sweden)

    Sitash Tetiana D.

    2017-03-01

    Full Text Available The article outlines the determinants of the state fiscal policy at the present stage of global transformations. Using the principles of financial science it is determined that regulation of financial flows within the fiscal sphere, namely centralization and redistribution of the GDP, which results in the regulation of the financial capacity of economic agents, is of importance. It is emphasized that the urgent measure for improving the tax model is re-considering the provision of fiscal incentives, which are used to stimulate the accumulation of capital, investment activity, innovation, increase of the competitiveness of national products, expansion of exports, increase of the level of the population employment. The necessity of applying the instruments of fiscal regulation of financial flows, which should take place on the basis of institutional economics emphasizing the analysis of institutional changes, the evolution of institutions and their impact on the behavior of participants of economic relations. At the same time it is determined that the maximum effect of fiscal regulation of financial flows is ensured when application of fiscal instruments is aimed not only at achieving the target values of parameters of financial flows but at overcoming institutional deformations as well. It is determined that the optimal movement of financial flows enables creating favorable conditions for development and maintenance of financial balance in the society and achievement of the necessary level of competitiveness of the national economy.

  6. Thermally determining flow and/or heat load distribution in parallel paths

    Science.gov (United States)

    Chainer, Timothy J.; Iyengar, Madhusudan K.; Parida, Pritish R.

    2016-12-13

    A method including obtaining calibration data for at least one sub-component in a heat transfer assembly, wherein the calibration data comprises at least one indication of coolant flow rate through the sub-component for a given surface temperature delta of the sub-component and a given heat load into said sub-component, determining a measured heat load into the sub-component, determining a measured surface temperature delta of the sub-component, and determining a coolant flow distribution in a first flow path comprising the sub-component from the calibration data according to the measured heat load and the measured surface temperature delta of the sub-component.

  7. Fast-responsive hydrogel as an injectable pump for rapid on-demand fluidic flow control.

    Science.gov (United States)

    Luo, Rongcong; Dinh, Ngoc-Duy; Chen, Chia-Hung

    2017-05-01

    Chemically synthesized functional hydrogels have been recognized as optimized soft pumps for on-demand fluidic regulation in micro-systems. However, the challenges regarding the slow responses of hydrogels have very much limited their application in effective fluidic flow control. In this study, a heterobifunctional crosslinker (4-hydroxybutyl acrylate)-enabled two-step hydrothermal phase separation process for preparing a highly porous hydrogel with fast response dynamics was investigated for the fabrication of novel microfluidic functional units, such as injectable valves and pumps. The cylinder-shaped hydrogel, with a diameter of 9 cm and a height of 2.5 cm at 25 °C, achieved a size reduction of approximately 70% in less than 30 s after the hydrogels were heated at 40 °C. By incorporating polypyrrole nanoparticles as photothermal transducers, a photo-responsive composite hydrogel was approached and exhibited a remotely triggerable fluidic regulation and pumping ability to generate significant flows, showing on-demand water-in-oil droplet generation by laser switching, whereby the droplet size could be tuned by adjusting the laser intensity and irradiation period with programmable manipulation.

  8. [Research on optimization of mathematical model of flow injection-hydride generation-atomic fluorescence spectrometry].

    Science.gov (United States)

    Cui, Jian; Zhao, Xue-Hong; Wang, Yan; Xiao, Ya-Bing; Jiang, Xue-Hui; Dai, Li

    2014-01-01

    Flow injection-hydride generation-atomic fluorescence spectrometry was a widely used method in the industries of health, environmental, geological and metallurgical fields for the merit of high sensitivity, wide measurement range and fast analytical speed. However, optimization of this method was too difficult as there exist so many parameters affecting the sensitivity and broadening. Generally, the optimal conditions were sought through several experiments. The present paper proposed a mathematical model between the parameters and sensitivity/broadening coefficients using the law of conservation of mass according to the characteristics of hydride chemical reaction and the composition of the system, which was proved to be accurate as comparing the theoretical simulation and experimental results through