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Luleå University of Technology

1. Karlsson, Christian A. M. Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system.

Degree: 2011, Luleå University of Technology

Fast precise moisture measurement in mineral process plants, has long been a difficult problem. In this master thesis a foundation for a new way of measurement using transmission line theory, is laid out. Macroscopic electro-magnetic properties of the measured sample can be linked to those of the individual constituents of the sample. Thus one is believed to be able to do a precise estimate of the amount of moisture in a sample. In our case the samples are moist magnetite concentrate. The characterization of sample macroscopic electro-magnetic properties is done by using a coaxial cell, performing frequency spectra measurement. In this master thesis, the electrical behavior that links the measured data to the macroscopic electro-magnetic properties is examined. It exists two setups, one inductive and one capacitive. The DC resistivity of the moist magnetite concentrate is determined and some interesting phenomena, suggested to be self potential were discovered. This phenomenon is in general known from geochemistry of mineral rich clays. This made the measurements of resistivity tricky to perform, some measurements were achieved and a new relation between moisture of the moist magnetite concentrate and resistivity is presented. Studies have been performed on the history of attempts of solving this problem, as well as current relevant research. Reference samples have been prepared in a geotechnical laboratory. Impedance frequency behavior of the measurement equipment is measured and presented, with different curves for different moisture content. From these measurements it is obvious that the moisture affects the impedance of the measurement equipment and thus it is possible to use this method to measure moisture content, if one can determine the electrical model which describes the measurement system. A few equivalent circuits of transmission lines have been discussed, and one was chosen to represent the purely coaxial part of the coaxial cell. Other parts have been modeled with other elements of AC theory. A new electrical model for the coaxial probe is proposed, based on LC resonances. Some Comsol FEM simulations have been performed on the coaxial cell, as well as on electric property sensors. Ideas to designs of electrical sensors are discussed. It is mainly the geometry which has been investigated. First it was proposed that a phenomenon of resonance occurs at the interface of the bottom and coaxial part of the cell, LC resonance. The resonance effect has later been investigated and identified as quarter wavelength resonance, due to the length of the measurement cell and change of wave velocity due to wave propagation in MUT. Simulations of proposed circuit equivalents in Orcad with PSpice have given some correlation with measured data for dry and non-conducting samples. There is still work to be done, to complete an accurate mathematical model of the system.

Validerat; 20110824 (anonymous)

Subjects/Keywords: Technology; Teknik; measurement; moisture; RF; electric permittivity; magnetic permeability; broad-band spectroscopy; frequency spectra; magnetite concentrate; Fe3O4; resistivity; equivalent circuits; coaxial cell; quarter wave resonance

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Karlsson, C. A. M. (2011). Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system. (Thesis). Luleå University of Technology. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Karlsson, Christian A M. “Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system.” 2011. Thesis, Luleå University of Technology. Accessed January 16, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Karlsson, Christian A M. “Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system.” 2011. Web. 16 Jan 2021.

Vancouver:

Karlsson CAM. Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system. [Internet] [Thesis]. Luleå University of Technology; 2011. [cited 2021 Jan 16]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Karlsson CAM. Sensus Aquae in Ferrum ac Air : Karakterisering av elektriska egenskaper hos ett fuktmätnings system. [Thesis]. Luleå University of Technology; 2011. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-54848

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Seetohul, L. Nitin. Novel applications of optical analytical techniques.

Degree: PhD, 2009, Teesside University

Novel applications of optical analytical techniques have been demonstrated in three general areas, namely application of broadband cavity enhanced absorption spectroscopy (BBCEAS) to the detection of liquid phase analytes, the use of total luminescence spectroscopy to discriminate between different type of teas and the development of an optical sensor to detect ammonia gas, based on the fluorescence quenching of a dye immobilised in a sol gel matrix. A simple BBCEAS setup has been developed with a view to perform sensitive visible wavelength measurements on liquid phase solutions. In the present work a simple low-cost experimental setup has been demonstrated for the measurement of the visible spectra of representative liquid-phase analytes in a 2 mm quartz cuvette placed at normal incidence to the cavity mirrors. Measurements on Ho3+ and sudan black with a white LED and the R ≥ 0.99 mirrors covered a broad wavelength range (~250 nm) and represents the largest wavelength range covered to date in a single BBCEAS experiment. The sensitivity of the technique as determined by the best αmin value was 5.1 x 10-5 cm-1 and was obtained using the R ≥ 0.99 mirrors. The best limit of detection (LOD) for the strong absorber brilliant blue-R, was approximately 620 pM. The optical setup was then optimised for the application of BBCEAS detection to an HPLC system. A 1 cm pathlength HPLC cell with a nominal volume of 70 ml was used in this study. The cavity was formed by two R ≥ 0.99 plano-concave mirrors with a bandwidth of ~ 420 – 670 nm. Two analytes rhodamine 6G and rhodamine B were chosen for separation by HPLC, as they were chemically similar species with distinctive visible spectra and would co-elute in an isocratic separation. The lowest value of amin obtained was 1.9 x 10-5 cm-1. The most significant advantage of the HPLC-BBCEAS study over previous studies arose from the recording of the absorption spectrum over a range of wavelengths. It was demonstrated that the spectral data collected could be represented as a contour plot which was useful in visualising analytes which nearly co-eluted. The LOD values for the two analytes studied indicated that the developed HPLC-BBCEAS setup was between 54 and 77 times more sensitive than a commercial HPLC system. For improved sensitivity and lower detection limits the low cost BBCEAS setup was used with a significantly longer 20 cm pathlength cell where the mirrors were in direct contact with the liquid phase analyte. This also reduced interface losses. The experiments were carried out using both R ³ 0.99 and R ³ 0.999 mirrors. The lowest αmin value obtained in this study was 2.8 x 10-7 cm-1 which is the lowest reported value to date for a liquid phase measurement, making this study the most sensitive liquid phase absorption measurement reported. The lowest LOD recorded was 4.6 pM, and was obtained for methylene blue with the R ³ 0.999 mirrors. A novel application of total luminescence spectroscopy to discriminate between different types of teas objectively was also investigated. A…

Subjects/Keywords: 543; broad band cavity enhanced absorption spectroscopy; tea classification via pattern recognition; analytical chemistry; HPLC detector; sol gel based optical ammonia sensor

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Seetohul, L. N. (2009). Novel applications of optical analytical techniques. (Doctoral Dissertation). Teesside University. Retrieved from https://research.tees.ac.uk/en/studentTheses/da6cf659-9213-4100-936d-7e774b18558c ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526681

Chicago Manual of Style (16th Edition):

Seetohul, L Nitin. “Novel applications of optical analytical techniques.” 2009. Doctoral Dissertation, Teesside University. Accessed January 16, 2021. https://research.tees.ac.uk/en/studentTheses/da6cf659-9213-4100-936d-7e774b18558c ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526681.

MLA Handbook (7th Edition):

Seetohul, L Nitin. “Novel applications of optical analytical techniques.” 2009. Web. 16 Jan 2021.

Vancouver:

Seetohul LN. Novel applications of optical analytical techniques. [Internet] [Doctoral dissertation]. Teesside University; 2009. [cited 2021 Jan 16]. Available from: https://research.tees.ac.uk/en/studentTheses/da6cf659-9213-4100-936d-7e774b18558c ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526681.

Council of Science Editors:

Seetohul LN. Novel applications of optical analytical techniques. [Doctoral Dissertation]. Teesside University; 2009. Available from: https://research.tees.ac.uk/en/studentTheses/da6cf659-9213-4100-936d-7e774b18558c ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526681

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