Proposal fiber optical sensor based on Mach-Zehnder interferometer for measurement of selected parameters in the traffic

Cílem práce bylo provést rešerši o principech činnosti vláknově optických interferometrů, nastudovat jejich funkcionality a na základě nabitých poznatků sestavit senzor, který dokáže detekovat projíždějící vozidlo nejvyšší možnou úspěšností. Výstupem práce je sestavení funkčního vzorku senzoru, který využívá výhod optických vláken jako je imunita vůči elektromagnetickému rušení, pasivita z hlediska napájení elektrickou energií a umožňuje detekovat průjezdy automobilů. Práce dále přináší úvodní poznatky z oblasti monitorování rychlosti vozidel, kdy se využívá dvou totožných senzorických jednotek v pevně definované vzdálenosti a rychlost je vypočtena na základě časového rozdílu průjezdu automobilů během průjezdu kolem obou senzorických jednotek.The aim of the work was to investigate the principles of fiber optic interferometers, to study their functionality, and to build a sensor that can detect the passing vehicle with the highest possible success. The output of the thesis is the assembly of a functional sample of a sensor that uses the advantages of optical fibers such as immunity to electromagnetic interference, passivity in terms of power supply and allows detection of car passes. The thesis also introduces introductory findings from the field of vehicle speed monitoring using two identical sensor units at a fixed distance and the speed is calculated based on the time difference of the passage of cars during the passage around the two sensing units.440 - Katedra telekomunikační technikyvýborn

Analysis Of the Uses the Fiber-Optic Sensor in the Tram Traffic

Cílem práce je provést rešerši o vláknově optických interferometrech v dopravních aplikacích a prakticky realizovat a otestovat interferometrický senzor v tramvajovém kolejovém provozu. Úvodní část práce popisuje základní principy funkcionality optických vláken a interferometrických typů senzorů. Porovnány jsou různé typy interferometrů a optických senzorů, které byly využity pro potřeby monitorování různých parametrů v kolejové dopravě. Na základě dříve nabitých vědomostí a nových zkušeností byl sestaven funkční vzorek Mach-Zehnderova senzoru vhodného i pro uložení do země pro detekci tramvajových vozidel. Tento senzor využívá výhod optických vláken jako je imunita vůči elektromagnetickému rušení, pasivita z hlediska napájení elektrickou energií či možnost vzdáleného vyhodnocení užitečné informace.The aim of this work is to search for fiber optic interferometers in traffic applications and to practically implement and test an interferometric sensor in tramway traffic. The introductory part describes the basic principles of the functionality of optical fibers and interferometric types of sensors. Different types of interferometers and optical sensors were compared, which were used for monitoring various parameters in rail transport. Based on previously acquired knowledge and new experience, a functional sample of the Mach-Zehnder sensor, suitable also for ground-based detection of tram vehicles, was assembled. This sensor takes advantage of optical fibers such as immunity to electromagnetic interference, passivity in terms of power supply and the possibility of remotely evaluating useful information.440 - Katedra telekomunikační technikyvelmi dobř

Prostorové rozložení a reakce volných atomů analytu, jejich reakce a reatomizace analytu v křemenných atomizátorech hydridů pro atomovou absorpční spektrometrii

Free Analyte Atom Distribution, Reactions and Analyte Reatomization in Quartz Tube Hydride Atomizers for Atomic Absorption Spectrometry Abstract of Dissertation Tomáš Matoušek The Dissertation presents summary of studies of processes taking place in quartz tube hydride atomizers for atomic absorption spectrometry. Spatially resolved measurements of free atoms of hydride forming elements within the quartz tube atomizers (QTA) have been introduced. Both the cross-sectional [1] and the longitudinal [2,3] free atom distribution has been thoroughly investigated, bringing valuable information concerning the nature of the processes taking place within QTA. From the practical point of view, no effects arising from an inhomogeneous free atom distribution are to be expected in the most common externally heated atomizer. The role of the tube surface in the decay of the free analyte atoms has been demonstrated. Strong evidence has been obtained on analyte reactions within the QTA, leading to the formation of polyatomic analyte particles enhancing the free atom decay. These reactions are responsible for calibration graph curvature or even roll-over. It should be noted that the existence of such particles was not directly proven here, e.g., by using non-specific absorption or light scattering. On the other hand,...Prostorové rozložení a reakce volných atomů analytu, jejich reakce a reatomizace analytu v křemenných atomizátorech hydridů pro atomovou absorpční spektrometrii Abstrakt dizertační práce Tomáš Matoušek Dizertační práce se zabývá studiem procesů v křemenných atomizátorech hydridů pro atomovou absorpční spektrometrii. Popsali jsme prostorově rozlišená měření volných atomů v křemenných atomizátorech (QTA). Podrobné zkoumání příčného [1] i podélného [2,3] rozložení volných atomů přineslo cenné poznatky o podstatě procesů probíhajících uvnitř QTA. Z praktického hlediska se pak v nejběžnějších vyhřívaných atomizátorech není třeba obávat jevů způsobených nehomogenní distribucí volných atomů. Demonstrovali jsme vliv povrchu trubice na zánik volných atomů analytu. Získali jsme silné indicie reakcí analytu uvnitř QTA, vedoucích k vytváření polyatomických částic urychlujících zánik volných atomů. Vznik těchto částic však nebyl přímo prokázán, například pozorováním nespecifické absorpce či rozptylem záření. Tyto reakce jsou zodpovědné za zakřivení či dokonce roll-over kalibračních křivek. Naopak se nepotvrdila dřívější hypotéza, že tyto jevy při vyšších koncentracích analytu jsou způsobeny nedostatkem vodíkových radikálů. Dále byly popsány procesy vedoucí k reatomizaci analytu na koncích optické trubice vyhřívaného...Department of Analytical ChemistryKatedra analytické chemieFaculty of SciencePřírodovědecká fakult

Optimization of Snake-like Robot Locomotion Using GA: Serpenoid Design

This work investigates the locomotion efficiency of snake-like robots through evolutionary optimization using the simulation framework PhysX (NVIDIA). The Genetic Algorithm (GA) is used to find the optimal forward head serpentine gait parameters, and the snake speed is taken into consideration in the optimization. A fitness function covering robot speed is based on a complex physics simulation in PhysX. A general serpenoid form is applied to each joint. Optimal gait parameters are calculated for a virtual model in a simulation environment. The fitness function evaluation uses the Simulation In the Loop (SIL) technique, where the virtual model is an approximation of a real snake-like robot. Experiments were performed using an 8-link snake robot with a given mass and a different body friction. The aim of the optimization was speed and length of the trace

Direct analysis and stability of methylated trivalent arsenic metabolites in cells and tissues

Chronic ingestion of water containing inorganic arsenic (iAs) has been linked to a variety of adverse health effects, including cancer, hypertension and diabetes. Current evidence suggests that the toxic methylated trivalent metabolites of iAs, methylarsonous acid (MAs) and dimethylarsinous acid (DMAsIII) play a key role in the etiology of these diseases. Both MAs and DMAsIII have been detected in urine of subjects exposed to iAs. However, the rapid oxidation of DMAsIII and, to a lesser extent, MAsIII in oxygen-rich environments leads to difficulties in the analysis of these metabolites in samples of urine collected in population studies. Results of our previous work indicate that MAsIII and DMAsIII are relatively stable in a reducing cellular environment and can be quantified in cells and tissues. In the present study, we used the oxidation state-specific hydride generation-cryotrapping-atomic absorption spectroscopy (HG-CT-AAS) to examine the presence and stability of these trivalent metabolites in the liver of mice and in UROtsa/F35 cells exposed to iAs. Tri- and pentavalent metabolites of iAs were analyzed directly (without chemical extraction or digestion). Liver homogenates prepared in cold deionized water and cell culture medium and lysates were stored at either 0 °C or −80 °C for up to 22 days. Both MAsIII and DMAsIII were stable in homogenates stored at −80 °C. In contrast, DMAsIII in homogenates stored at 0 °C began to oxidize to its pentavalent counterpart after 1 day; MAsIII remained stable for at least 3 weeks under these conditions. MAsIII and DMAsIII generated in UROtsa/F35 cultures were stable for 3 weeks when culture media and cell lysates were stored at −80 °C. These results suggest that samples of cells and tissues represent suitable material for the quantitative, oxidation state-specific analysis of As in laboratory and population studies examining the metabolism or toxic effects of this metalloid

Speciation Analysis of Arsenic by Selective Hydride Generation-Cryotrapping-Atomic Fluorescence Spectrometry with Flame-in-Gas-Shield Atomizer: Achieving Extremely Low Detection Limits with Inexpensive Instrumentation

This work describes the method of a selective hydride generation-cryotrapping (HG-CT) coupled to an extremely sensitive but simple in-house assembled and designed atomic fluorescence spectrometry (AFS) instrument for determination of toxicologically important As species. Here, an advanced flame-in-gas-shield atomizer (FIGS) was interfaced to HG-CT and its performance was compared to a standard miniature diffusion flame (MDF) atomizer. A significant improvement both in sensitivity and baseline noise was found that was reflected in improved (4 times) limits of detection (LODs). The yielded LODs with the FIGS atomizer were 0.44, 0.74, 0.15, 0.17 and 0.67 ng L–1 for arsenite, total inorganic, mono-, dimethylated As and trimethylarsine oxide, respectively. Moreover, the sensitivities with FIGS and MDF were equal for all As species, allowing for the possibility of single species standardization with arsenate standard for accurate quantification of all other As species. The accuracy of HG-CT-AFS with FIGS was verified by speciation analysis in two samples of bottled drinking water and certified reference materials, NRC CASS-5 (nearshore seawater) and SLRS-5 (river water) that contain traces of methylated As species. As speciation was in agreement with results previously reported and sums of all quantified species corresponded with the certified total As. The feasibility of HG-CT-AFS with FIGS was also demonstrated by the speciation analysis in microsamples of exfoliated bladder epithelial cells isolated from human urine. The results for the sums of trivalent and pentavalent As species corresponded well with the reference results obtained by HG-CT-ICPMS (inductively coupled plasma mass spectrometry)

Methylated trivalent arsenicals are potent inhibitors of glucose stimulated insulin secretion by murine pancreatic islets

Epidemiologic evidence has linked chronic exposure to inorganic arsenic (iAs) with an increased prevalence of diabetes mellitus. Laboratory studies have identified several mechanisms by which iAs can impair glucose homeostasis. We have previously shown that micromolar concentrations of arsenite (iAsIII) or its methylated trivalent metabolites, methylarsonite (MAsIII) and dimethylarsinite (DMAsIII), inhibit the insulin-activated signal transduction pathway, resulting in insulin resistance in adipocytes. Our present study examined effects of the trivalent arsenicals on insulin secretion by intact pancreatic islets isolated from C57BL/6 mice. We found that 48-hour exposures to low subtoxic concentrations of iAsIII, MAsIII or DMAsIII inhibited glucose-stimulated insulin secretion (GSIS), but not basal insulin secretion. MAsIII and DMAsIII were more potent than iAsIII as GSIS inhibitors with estimated IC50≤0.1 μM. The exposures had little or no effects on insulin content of the islets or on insulin expression, suggesting that trivalent arsenicals interfere with mechanisms regulating packaging of the insulin transport vesicles or with translocation of these vesicles to the plasma membrane. Notably, the inhibition of GSIS by iAsIII, MAsIII or DMAsIII could be reversed by a 24-hour incubation of the islets in arsenic-free medium. These results suggest that the insulin producing pancreatic β-cells are among the targets for iAs exposure and that the inhibition of GSIS by low concentrations of the methylated metabolites of iAs may be the key mechanism of iAs-induced diabetes

Direct Analysis of Methylated Trivalent Arsenicals in Mouse Liver by Hydride Generation-Cryotrapping-Atomic Absorption Spectrometry

Growing evidence suggest that the methylated trivalent metabolites of inorganic arsenic (iAs), methylarsonite (MAsIII) and dimethylarsinite (DMAsIII), contribute to adverse effects of iAs exposure. However, the lack of suitable methods has hindered the quantitative analysis of MAsIII and DMAsIII in complex biological matrices. Here, we show that hydride generation-cryotrapping-atomic absorption spectrometry can quantify both MAsIII and DMAsIII in livers of mice exposed to iAs. No sample extraction is required, thus limiting MAsIII or DMAsIII oxidation prior to analysis. The limits of detection are below 6 ng As/g of tissue, making this method suitable even for studies examining low exposures to iAs