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ELECTROCHEMICAL DETECTOR WITH ELECTRODES ARRAY AND ROTATING DISK
SAJDLOVÁ, Zuzana
The thesis deals with the testing and optimization of hydrodynamic conditions of the electrochemical detector, which consists of a flow cell containing the electrochemical sensor with an array of electrodes. The flow cell includes a rotating disc-shaped component, which allows radial flow of analytes along the sensor electrodes. This principle imitates the rotating disk electrode, with the difference that here the electrodes are immobile. Hydrodynamic phenomena in this case are similar to RDE. Therefore, the theoretical part of my work deals with hydrodynamics and mass transfer for the well-described case of rotating disk electrode. It was found that in the current set-up under certain conditions, an analyte flowed back from the output cell channel to the sensor, even at the laminar flow. This causes a nonlinear response of the electrodes and their low reproducibility. The solution is to reduce the distance between the rotation component and the electrodes surface and reduce flow speed of analyzed liquid towards the sensor. A novel type of sensor with annular electrodes was designed and tested. It showed four times higher conversion rate of the analyte compared with the originally used AC9 electrochemical sensor having electrodes in the form of full circles lying on a circumference of a common circle. Based on calculations, conversion of the analyte on the plane electrode can be increased up to 100% when using this annular sensor, adjusting flow cell and reducing of the input flow rate. The detector was connected to the liquid chromatograph and its function was tested on two substances - ascorbic acid and dopamine. For the current detector these parameters were set: dynamic range, linearity, noise, detection limit, time constant and the temperature range at which the detector can be operated.
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Utilization of Electric Conductivity Method in Resarch of Hydrodynamics of TBR,PartII, Final Research Report, Task H, Project FT-TA/039, 2006.
Jiřičný, Vladimír ; Staněk, Vladimír ; Hanika, Jiří ; Vychodilová, Hana ; Stavárek, Petr ; Vlček, Dalibor ; Karfík, David ; Tukač, V. ; Chyba, V. ; Lederer, J. ; Kubička, D.
Research and development of electric conductivity method for measurement of RTD, liquid hold up and axial mixing (Pe number) of liquid phase in trickle bed reactor.
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Utilization of Electric Conductivity Method in Resarch of Hydrodynamics of TBR, PartII, Intermediate Research Report, Task G and H, Project FT-TA/039, 2006.
Jiřičný, Vladimír ; Staněk, Vladimír ; Hanika, Jiří ; Ondráček, Jakub ; Vychodilová, Hana ; Stavárek, Petr ; Vlček, Dalibor ; Karfík, David ; Tukač, V. ; Lederer, J. ; Kubička, D.
Research and development of electric conductivity method for measurement of RTD, liquid hold up and axial mixing (Pe number) of liquid phase in trickle bed reactor.
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Hydrodynamika mozkomíšní tekutiny v páteřním kanálu
Kaczmarská, A. ; Vaněk, P. ; Maršík, František ; Převorovská, Světlana ; Otáhal, S. ; Otáhal, J.
In previous modelling study of the cerebrospinal fluid transportation we have shown that main source of the hydrodynamical resistance and compliance of the craniospinal system is cervical part of the spinal canal. The aim of our present study is the investigation of the influence of the cervical spine degenerative changes on the hydrodynamical parameters of the craniospinal system. The results obtained by using of the numerical model of the cerebrospinal fluid flow show the significant influence of the cervical spine degenerative changes on the hydrodynamics of this system.
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Transition Phenomena in Trickle Bed Reactor under Steady Stay Gas/liquid Downflow. Part 1
Jiřičný, Vladimír ; Staněk, Vladimír ; Ondráček, Jakub ; Vychodilová, Hana ; Křišťál, Jiří ; Stavárek, Petr ; Vlček, Dalibor ; Karfík, David ; Lederer, J. ; Šimek, J.
Experimental measurement of co current gas/liquid downflow under conditions of steady state. Measurement of the effect of liqud physical properties and type od packing on pressure drop profile along the packed bed layer.
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