Using RuO2 anode for chlorine dioxide production in an un-divided electrochemical cell

Chlorine dioxide is a well known powerful disinfectant. Although there are several chemical and electrochemical methods developed for on-line chlorine dioxide generation, the details are mostly confined as patents. We studied in this work the electrochemical generation of dissolved chlorine dioxide from an un-buffered solution of sodium chlorite and sodium chloride mixture in an un-divided electrochemical cell set-up with RuO2-coated-Ti anode and Pt-coated-Ti cathode under constant current mode. Various process parameters including feed flow rate (10 to 150 ml/min), feed solution pH (2.3 to 9.4), concentration of sodium chloride (0 to 170 mM), concentration of sodium chlorite (0 to 7.7 mM), and the applied current (100 to 1,200 mA) were optimized. Experiments were conducted by performing single pass experiments, with no circulation. The current efficiency and the power consumption were calculated for the optimized conditions, and compared with IrO2 electrode of our previous investigation.

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379. Measuring Chlorine and Chlorine Dioxide with Electrochemical Cell Analyzers

10.3320/1.2763730 ◽

2000 ◽

Author(s):

N. Goyer ◽

R. Gravel

Keyword(s):

Chlorine Dioxide ◽

Electrochemical Cell

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Respirometry for determination of the influents SS-concentration

Water Science & Technology ◽

10.2166/wst.1996.0031 ◽

1996 ◽

Vol 33 (1) ◽

pp. 311-323 ◽

Cited By ~ 2

Author(s):

A. Witteborg ◽

A. van der Last ◽

R. Hamming ◽

I. Hemmers

Keyword(s):

Experimental Design ◽

Activated Sludge ◽

Substrate Concentration ◽

Full Scale ◽

Activated Sludge Process ◽

Respiration Rates ◽

On Line ◽

Large Measurement ◽

Set Up

A method is presented for determining influent readily biodegradable substrate concentration (SS). The method is based on three different respiration rates, which can be measured with a continuous respiration meter which is operated in a cyclic way. Within the respiration meter nitrification is inhibited through the addition of ATU. Simulations were used to develop the respirometry set-up and decide upon the experimental design. The method was tested as part of a large measurement programme executed at a full-scale plant. The proposed respirometry set-up has been shown to be suitable for a semi-on-line determination of an influent SS which is fully based on the IAWQ #1 vision of the activated sludge process. The YH and the KS play a major role in the principle, and should be measured directly from the process.

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Fabrication of freestanding Pt nanowires for use as thermal anemometry probes in turbulence measurements

Microsystems & Nanoengineering ◽

10.1038/s41378-021-00255-0 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Hai Le-The ◽

Christian Küchler ◽

Albert van den Berg ◽

Eberhard Bodenschatz ◽

Detlef Lohse ◽

...

Keyword(s):

Room Temperature ◽

Fluid Velocity ◽

Current Mode ◽

Constant Current ◽

Small Scale ◽

Turbulence Measurements ◽

High Dynamic ◽

Scale Turbulence ◽

Constant Current Mode ◽

Pt Nanowires

AbstractWe report a robust fabrication method for patterning freestanding Pt nanowires for use as thermal anemometry probes for small-scale turbulence measurements. Using e-beam lithography, high aspect ratio Pt nanowires (~300 nm width, ~70 µm length, ~100 nm thickness) were patterned on the surface of oxidized silicon (Si) wafers. Combining wet etching processes with dry etching processes, these Pt nanowires were successfully released, rendering them freestanding between two silicon dioxide (SiO2) beams supported on Si cantilevers. Moreover, the unique design of the bridge holding the device allowed gentle release of the device without damaging the Pt nanowires. The total fabrication time was minimized by restricting the use of e-beam lithography to the patterning of the Pt nanowires, while standard photolithography was employed for other parts of the devices. We demonstrate that the fabricated sensors are suitable for turbulence measurements when operated in constant-current mode. A robust calibration between the output voltage and the fluid velocity was established over the velocity range from 0.5 to 5 m s−1 in a SF6 atmosphere at a pressure of 2 bar and a temperature of 21 °C. The sensing signal from the nanowires showed negligible drift over a period of several hours. Moreover, we confirmed that the nanowires can withstand high dynamic pressures by testing them in air at room temperature for velocities up to 55 m s−1.

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WWW.TELD.NET: Online Courseware Engine for Teaching by Examples and Learning by Doing

Journal of Educational Technology Systems ◽

10.2190/60jh-hhnh-62g3-qh9r ◽

2001 ◽

Vol 29 (3) ◽

pp. 219-235 ◽

Cited By ~ 1

Author(s):

G. Q. Huang ◽

B. Shen ◽

K. L. Mak

Keyword(s):

Teaching And Learning ◽

Virtual Classroom ◽

Learning By Doing ◽

General Purpose ◽

Project Based Learning ◽

Course Materials ◽

Summative Assessments ◽

On Line ◽

Set Up ◽

Electronic Delivery

TELD stands for “Teaching by Examples and Learning by Doing.” It is an on-line courseware engine over the World Wide Web. There are four folds of meanings in TELD. First, TELD represents a teaching and learning method that unifies a number of contemporary methods such as Problem-Based Learning (PBL) in medical education, Project-Based Learning (PBL) in engineering education, and Case Method (CM) in business education. Second, TELD serves as a Web server for hosting teaching and learning materials especially based on the TELD method. A variety of on-line facilities are provided for editing and uploading course materials such as syllabus, schedule, curriculum, examples of case study, exercises of mini-project, formative and summative assessments, etc. Third, TELD is a courseware search engine where educators are able to register their course materials and search for materials suitable for a particular course. In contrast with general-purpose search engines, TELD is set up for the special purpose of education. Therefore, the time and efforts spent on surfing are expected to be reduced dramatically. Finally, TELD is an on-line virtual classroom for electronic delivery of electronic curriculum materials. In addition to providing the lecture notes, TELD not only provides discussion questions for conducting in-class discussions and homework as formative assessment but also provides facilities for students to plan and submit their group work. This article presents an overview of the TELD courseware engine together with its background and underlying philosophy.

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Design and Implementation of Mid-Frequency Magnetron Sputtering Power Supply Based on TL494 and MCU

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.709.408 ◽

2013 ◽

Vol 709 ◽

pp. 408-412

Author(s):

Yan Ling Zhao ◽

Rong Xing Liu

Keyword(s):

Magnetron Sputtering ◽

Power Supply ◽

Current Mode ◽

Voltage Regulation ◽

Control Circuit ◽

Constant Current ◽

Loop Control ◽

Pulse Width Modulator ◽

Digital Pulse ◽

The Stability

Abstract. A mid-frequency magnetron sputtering (MFMS) power supply based on TL494 and MCU was introduced. A Buck Chopper and full bridge inverter were applied to the main circuit. The PWM controller TL494 was used in the Buck voltage-regulation control circuit to realize closed loop control. The drive signal of the IGBT in full bridge inverter was based on precise digital pulse width modulator (DPWM) signal produced by the MCU M30290. The DPWM can be set by potentiometer so the power supply can output the square wave with adjustable frequency and duty cycle. The power supply was operated in constant current mode. For micro or strong arcing of the target, different safeguards were adopted by the control circuit. At last, the system test and experimental results show that the stability, reliability and tuning range of the MFMS power supply can meet the requirements of the magnetron sputtering coating.

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Optimum three-point linkage set up for improving the quality of soil spectra and the accuracy of soil phosphorus measured using an on-line visible and near infrared sensor

Soil and Tillage Research ◽

10.1016/j.still.2008.10.006 ◽

2009 ◽

Vol 103 (1) ◽

pp. 144-152 ◽

Cited By ~ 37

Author(s):

A.M. Mouazen ◽

M.R. Maleki ◽

L. Cockx ◽

M. Van Meirvenne ◽

L.H.J. Van Holm ◽

...

Keyword(s):

Near Infrared ◽

Soil Phosphorus ◽

Infrared Sensor ◽

On Line ◽

Set Up

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COMPLEX DYNAMICS AND FAST-SLOW SCALE INSTABILITY IN CURRENT-MODE CONTROLLED BUCK CONVERTER WITH CONSTANT CURRENT LOAD

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127413500624 ◽

2013 ◽

Vol 23 (04) ◽

pp. 1350062 ◽

Cited By ~ 10

Author(s):

GUOHUA ZHOU ◽

BOCHENG BAO ◽

JIANPING XU

Keyword(s):

Complex Dynamics ◽

Period Doubling ◽

Current Mode ◽

Input Voltage ◽

Second Order ◽

Buck Converter ◽

Constant Current ◽

Current Load ◽

Time Model ◽

Conduction Mode

The complex dynamics and coexisting fast-slow scale instability in current-mode controlled buck converter with constant current load (CCL), operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM), are investigated in this paper. Via cycle-by-cycle computer simulation and experimental measurement of current-mode controlled buck converter with CCL, it is found that a unique fast-slow scale instability exists in the second-order switching converter. It is also found that a unique period-doubling accompanied by Neimark–Sacker bifurcation exists in this simple second-order converter, which is different from period-doubling or Neimark–Sacker bifurcations reported previously. Based on a nonlinear discrete-time model and the corresponding Jacobian, the effects of CCL and input voltage on the dynamics of current-mode controlled buck converter are investigated and verified theoretically. Fixed point analysis for slow-scale low-frequency oscillation is also given to verify the dynamics and the coexisting fast-slow scale instability.

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Effect of Grinding Aids on the Fracture Energy of Mica

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.402.503 ◽

2011 ◽

Vol 402 ◽

pp. 503-509

Author(s):

Ze Hong Wang ◽

Fu Jia Yu ◽

Shan Cai ◽

Shan Zhi Deng ◽

Roger Horn

Keyword(s):

Sodium Chloride ◽

Fracture Energy ◽

Sodium Citrate ◽

Ph Value ◽

Sodium Tripolyphosphate ◽

Experimental System ◽

Ammonium Bromide ◽

Solution Ph ◽

Grinding Aids ◽

Slurry Rheology

An extension of the classical Obriemoff experiments has been set up to measure the fracture energy of mica. This experimental system will be entirely independent of slurry rheology. CTAB (Cetyl Trimethyl Ammonium Bromide), sodium tripolyphosphate, sodium hexametaphosphate, and tri-sodium citrate are used as grinding aids in this study and the fracture energy has been measured for mica in air, water, and water with the addition of various concentrations of these grinding aids. The results show that the fracture energy of mica in water is about half of what it is in air. Grinding aids are shown to reduce the fracture energy of mica, but not dramatically. Addition of grinding aids reduces the fracture energy by a further 10-20%, with tri-sodium citrate appearing to be the most effective. For each grinding aid there appears to be an optimal concentration, typically around 10 mmol. An experiment is also done with sodium chloride at a range of concentrations to investigate the mechanism of these grinding aids, but no reduction in fracture energy (compared to water) was observed, hence the molecular-level mechanism of action of these grinding aids remains unclear. The effect of solution pH values on the fracture energy are also investigated using tri-sodium citrate and sodium chloride. The results show that the solution pH value may effect on the fracture energy of mica. So, in practice, both concentration and pH value of solution are important for getting better grinding results.

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