Dissertationen zum Thema „Water detection“
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1
Chienthavorn, Orapin. „Detection in superheated water chromatography“. Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/32394.
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Superheated water has been used successfully as an eluent in liquid chromatography and has been coupled to various modes of detection, ultraviolet (UV), fluorescence, and nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). A number of compounds were examined on poly(styrene-divinylbenzene) (PS-OVB), polybutadiene (PBO), and octadecylsilyl bonded silica (OOS) column with isothermal and temperature programmes.
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Bergua, Canudo José Francisco. „Nanobiosensors for contaminants detection in water“. Doctoral thesis, TDX (Tesis Doctorals en Xarxa), 2020. http://hdl.handle.net/10803/670394.
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Aquesta tesi té com a objectiu desenvolupar biosensors per al monitoratge ambiental. Primer, s'ha desenvolupat un biosensor colorimètric basat en lateral flow strips (LFS) per a la detecció i quantificació d'Escherichia coli com a indicador fecal universal. En aquest cas, nanopartícules d'or (AuNP) s'utilitzen com a transductors òptics i anticossos policlonals com a elements de bioreconeixement per capturar, marcar i indicar la presència del bacteri. Paral·lelament, s'ha desenvolupat un sistema de filtració per millorar la sensibilitat dels LFS. L'optimització del flux de la mostra a través dels diferents materials s'ha realitzat mitjançant una tècnica innovadora basada en el seguiment del flux del bacteri bioluminescent Aliivibrio fischeri, similar en grandària i forma a E. coli. Finalment, aquests LFS s'han provat amb mostres d'aigua de rius i aigües residuals, mostrant una sensibilitat similar i bona reproductibilitat i selectivitat en tots els casos.
En segon lloc, s'ha desenvolupat un biosensor de toxicitat bioluminescent per a la detecció i quantificació de pesticides en mostres d'aigua. En particular, Aliivibrio fischeri, un bacteri bioluminescent, s'ha utilitzat com a element de bioreconeixement i transductor perquè augmenta i disminueix la bioluminescència d'acord amb la concentració de compostos tòxics en les mostres d'aigua. A més, l'òxid de grafè (GO) s'ha utilitzat com un potenciador del creixement no específic per promoure el creixement bacterià i augmentar la sensibilitat del sistema al detectar parcialment la bioluminescència emesa per A. fischeri. La detecció i quantificació de la bioluminescència es va realitzar amb un telèfon mòbil que permet una avaluació de la toxicitat de l'aigua de forma portàtil, més barata, i més fàcil d'utilitzar que els estàndards en els laboratoris.
En tercer lloc, s'ha desenvolupat una plataforma portàtil basada en un telèfon mòbil per a realitzar assajos que requereixen una detecció òptica, incloent assaigs colorimètrics, fluorescents i bioluminescents. Aquesta plataforma s'ha utilitzat per dur a terme i analitzar proves ELISA estàndard basades en resultats colorimètrics per a la detecció de la immunoglobulina humana i una proteïna del coronavirus. A més, el sistema permet realitzar un seguiment de l'agregació de AuNPs en funció del color de la solució. D'altra banda, la plataforma s'ha utilitzat per detectar i quantificar quantum dots (QD) i altres indicadors fluorescents (per exemple, fluoresceïna), i per a fer proves ELISA fluorescents basades en aquests transductors. A més, la plataforma permet realitzar lectures bioluminiscents amb aplicacions com l'anàlisi de la toxicitat de l'aigua. Finalment, la plataforma és útil per al cultiu de bacteris, mesuraments de terbolesa i detecció de resistència a antibiòtics.Esta tesis tiene como objetivo desarrollar biosensores para el monitoreo ambiental. Primero, se ha desarrollado un biosensor colorimétrico basado en lateral flow strips (LFS) para la detección y cuantificación de Escherichia coli como indicador fecal universal. En este caso, nanopartículas de oro (AuNP) se utilizan como transductores ópticos y anticuerpos policlonales como elementos de bioreconocimiento para capturar, marcar e indicar la presencia de la bacteria. Paralelamente, se ha desarrollado un sistema de filtración para mejorar la sensibilidad de las LFS. La optimización del flujo de la muestra a través de los diferentes materiales ha realizado mediante una técnica innovadora basada en el seguimiento del flujo de la bacteria bioluminiscente Aliivibrio fischeri, similar en tamaño y forma a E. coli. Finalmente, estos LFB se han probado con muestras de agua de ríos y aguas residuales, mostrando una sensibilidad similar y buena reproducibilidad y selectividad en todos los casos. En segundo lugar, se ha desarrollado un biosensor de toxicidad bioluminiscente para la detección y cuantificación de pesticidas en muestras de agua. En particular, Aliivibrio fischeri, una bacteria bioluminiscente, se ha utilizado como elemento de bioreconocimiento y transductor porque aumenta y disminuye la bioluminiscencia de acuerdo con la concentración de compuestos tóxicos en las muestras de agua. Además, el óxido de grafeno (GO) se ha utilizado como un potenciador del crecimiento no específico para promover el crecimiento bacteriano y aumentar la sensibilidad del sistema al detectar parcialmente la bioluminiscencia emitida por A. fischeri. La detección y cuantificación de la bioluminiscencia se realizó con un teléfono móvil que permite una evaluación de la toxicidad del agua de forma portátil, más barata, y más fácil de usar que los estándares en los laboratorios. En tercer lugar, se ha desarrollado una plataforma portátil basada en un teléfono móvil para realizar ensayos que requieren una detección óptica, incluyendo ensayos colorimétricos, fluorescentes y bioluminiscentes. Esta plataforma se ha utilizado para llevar a cabo y analizar pruebas ELISA estándar basadas en resultados colorimétricos para la detección de la inmunoglobulina humana y una proteína del coronavirus. Además, el sistema permite realizar un seguimiento de la agregación de AuNPs en función del color de la solución. Por otro lado, la plataforma se ha utilizado para detectar y cuantificar quantum dots (QD) y otros indicadores fluorescentes (por ejemplo, fluoresceína), así como para realizar pruebas ELISA fluorescentes basadas en estos transductores. Además, la plataforma permite realizar lecturas bioluminiscentes con aplicaciones como el análisis de la toxicidad del agua. Finalmente, la plataforma es útil para el cultivo de bacterias, mediciones de turbidez y detección de resistencia a antibióticos.
This thesis aims to develop biosensing tools for environmental monitoring. First, a colorimetric lateral flow biosensor (LFB) has been developed for the detection and quantification of Escherichia coli as a universal fecal indicator. Gold nanoparticles (AuNPs) are used as optical transducers and polyclonal antibodies as the biorecognition elements to capture, tag and indicate the presence of the bacteria. In parallel, a filtration system has been developed to improve the sensitivity of the LFBs. The optimization of the flow properties of the different lateral flow materials has been done by an innovative technique based on the tracking of the flow of the bioluminescent bacteria Aliivibrio fischeri, similar in size and shape to E. coli. Eventually, these LFBs have been tested with river and sewage waters, showing similar sensitivity and good reproducibility and selectivity in all the cases. Second, a bioluminescent toxicity biosensor has been developed for the detection and quantification of pesticides in water samples. In particular, Aliivibrio fischeri, a bioluminescent bacteria, has been used as the biorecognition element and the transducer because it turns up and down bioluminescence according to the concentration of toxic compounds within the water samples. Besides, graphene-oxide (GO) has been used as a non-specific growth enhancer to promote bacterial growth and increase the sensitivity of the system by partially screening the bioluminescence emitted by A. fischeri. The detection and quantification of the bioluminescence has been performed by a smartphone that allows for a cheaper, more user friendly, and portable water toxicity assessment. Third, a smartphone-based portable platform has been developed for the performance of optical sensing, including colorimetric, fluorescent, and bioluminescent assays. This platform has been used to perform and read standard ELISA tests based on colorimetric outputs for human IgG and coronavirus detection. In addition, the system allows for tracking AuNPs aggregation based on the color output of the solution. On the other hand, the platform has been used to detect and quantify quantum dots (QDs) and other fluorescent reporters (i.e. fluorescein), as well as performing fluorescent ELISA tests based on these transducers. Next, the platform allows for bioluminescent readouts with applications in toxicity analysis. Eventually, the platform is suitable for bacteria culture, turbidity measurements, and drug screening for antibiotic resistances assessment.
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Gao, Yan. „Leak detection in plastic water pipes“. Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423122.
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Samuelsson, Oscar. „Fault detection in water resource recovery facilities“. Licentiate thesis, Uppsala universitet, Avdelningen för systemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-329777.
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Reliable sensor values are important for resource-efficient control and operations of wastewater treatment processes. Automatic fault detection methods are necessary to monitor the increasing amount of data produced in any modern water resource recovery facility (WRRF). Most on-line measurements exhibit large variations under normal conditions, due to considerable variations in the influent flow. The work reported in this licentiate thesis deals with fault detection in WRRFs. In the first paper, we studied how Gaussian process regression (GPR), a probabilistic machine learning method, could be applied for fault detection in WRRFs. The results showed that the standard parameter estimation method for GPR suffered from local optima which could be solved by instead estimating the distribution of the parameters with a sequential Monte Carlo algorithm (GPR-SMC). The GPR-SMC allowed for automatic estimation of missing data in a simulated influent flow signal with high noise, which is a representative signal for on-line sensors in WRRFs. In addition, the GPR-SMC provided uncertainty predictions for the estimated data and accurate sensor noise estimates. Care should be taken in selecting a suitable kernel for GPR, since the results were in contrast to the general assumption that prior knowledge can easily be encoded by means of selecting a proper kernel. Here, the autocorrelation graph was found useful as diagnostic tool for selecting a proper kernel. In the second paper, we studied how active fault detection (AFD) could be used to reveal information about the sensor status. The AFD was implemented by evaluating the change in a dissolved oxygen (DO)-signal caused by the sensor's automatic cleaning system. Fault signatures were obtained for fouling and several other sensor faults such as a worn out or mechanically damaged membrane. This demonstrates the potential of AFD, not only for fault detection, but also for fault diagnosis. Interestingly, the progression of the sensor bias due to organic biofilm fouling differed depending on the measurement technique used within the DO-sensor. This is new knowledge that is valuable for process control and should be further studied. The AFD was implemented on a full scale system to demonstrate its applicability, which is rarely done in research papers in the field of WRRFs.
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Gelin, Martin, und Skogsberg Rikard Fridsén. „Water Contamination Detection With Artificial Neural Networks“. Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-295605.
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Drinking water is one of our most important re- sources, so the ability to reliably monitor harmful contaminations in our water distribution network is vital. In order to minimize false alarms for water monitoring, while keeping a high sensitivity, a machine learning approach was evaluated in this project. Measurement data captured with a new kind of sensor, an electronic tongue, was provided by Linköping university. The solution was an artificial neural network, in the structure of an Autoencoder, which could learn the dynamic behaviour of natural deviations and with a false alarm rate of approximately one false alarm per week. This was done by evaluating the data and assembling an input structure to account for daily cyclic phenomena, which then was used to train the neural network. The solution could detect anomalies as small as 1.5% by comparing the input with the reconstructed vector, and raise an alarm. In conclusion, an Autoencoder is a viable method for detecting anomalies in water quality.Drickvatten är en av våra mest värdefulla tillgångar, det är därför mycket viktigt att det finns sätt att pålitligt övervaka om dricksvattennätet blivit förorenat. För att kunna minimera antalet falsklarm och samtidigt ha hög känslighet mot dessa föroreningar undersöktes och implementerades en lösning med maskininlärningsalgoritmer. Mätdata tillhandahölls av Linköpings universitet och kom från en ny sensor kallad elektronisk tunga. Lösningen var ett artificiellt neuralt nätverk i form av en Autoencoder, som kunde lära sig det dynamiska beteende som ofarliga avvikelser utgjorde. Detta gav en lösning som i medel gav ett falsklarm per sju dagar. Detta gjordes genom att utvärdera rådata och konstruera en struktur på indata som tar hänsyn till dygnsbunda naturliga fenomen. Denna struktur användes sedan för att träna det neurala nätverket. Lösningen kunde upptäcka fel ner till 1.5% genom att jämföra indata med den rekonstruerade vektorn, och på så sätt ge ett alarm.
Kandidatexjobb i elektroteknik 2020, KTH, Stockholm
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Nobliá, Matilda, und Christian Ryan. „Contamination Event Detection in Water Distribution Systems“. Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214698.
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In any society, making sure that its citizens havea clean water supply is a fundamental issue. By modernizingthe way water distribution systems (WDSs) are monitored andcontrolled, the impact of contamination can be maintained andminimized. By using sensors that monitor relevant physicalparameters, a system that detects contamination and limitspopulation exposure can be designed. To achieve this, the workpresented in this report is focused on three main topics.Firstly, parameters for determining water quality are examined.This is the basis for choosing relevant sensors. Secondly,a study of contamination event detection (CED) is presented, inparticular a method to determine whether water is contaminatedor not based on sensor measurements is proposed. This iscompleted through the use of binary hypothesis testing as wellas examining existing sensors. Thirdly, the problem of optimalsensor placement in a WDS is studied. In extension, a greedyalgorithm is implemented to optimally place sensors in a modelof real-world network.
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Mvelase, Mashinga Johannes. „Radon escape from water“. Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_3869_1307688700.
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This thesis aims to measure the rate of radon loss from water in a systematic way. The dependence on surface area, temperature and concentration will be investigated. The experiments were done at UWC by creating radon using radium sources and then measuring the radon concentrations inside a vacuum chamber to obtain the speed of radon escape from the water. The results are compared to a model [Cal 2002] where the radon concentration in the air and hence the transfer rate is measured using a RAD7 radon detector. Since the equations cannot be solved analytically, a numerical solution is employed. The radon transfer velocity coefficient is found to be (1.9±
0.5)×
10-6m/s. This value indicates that the escape of radon should not be a problem when a sample is open to the air for a minute or two.
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Walrath, Karen Elizabeth. „Evanescent wave spectroscopy for detection of water and water treeing in polymers“. Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/40582.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 185-191).
by Karen Elizabeth Walrath.
Ph.D.
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Wennberg, Aina Charlotte. „PCR-detection of Vibrio cholerae in ballast water“. Thesis, Norwegian University of Science and Technology, Department of Biotechnology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-6883.
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Parent, Uribe Santiago. „Endotoxins detection and control in drinking water systems“. Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100231.
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Endotoxins are a constituent of the lipopolysaccharide (LPS) complexes present in the outer layer of the cell wall of most Gram-negative bacteria and some cyanobacteria. The ingestion by a typical adult of amounts exceeding 1,000 endotoxin units (EUs) can cause fever, diarrhoea, vomiting, acute respiratory illnesses, and lung inflammation. In contrast, much smaller doses may lead to protective immunity against allergic diseases.Endotoxins can be released in the air as well as in the water; previous studies have mainly focused on airborne endotoxins. Although many studies on endotoxins in raw and treated drinking waters have been performed, few have assessed seasonal variations and none have been conducted in Eastern Canada. Furthermore, a clear understanding of removal of endotoxins by various water treatment processes is still required.
Two methods to measure the concentrations of endotoxin were used and compared, the Limulus Amebocyte Lysate test (LAL) and the recombinant Factor C test (rFC). Raw water samples were taken from various drinking water sources around the Island of Montreal. The effects of free chlorine, UV radiation, and ozone were studied in batch experiments on filtered water samples via typical dosages and fluences used in drinking water treatment facilities. Residual concentrations for free chlorine were 0.8 and 1.6 mg/L; ozone doses were 0.5 and 1 mg/L; UV fluences were 40 and 100 mWs/cm2. Detention times of 20 and 60 minutes were tested for chlorine and 5 and 20 minutes for ozone. Grab sampling from three drinking water treatment plants in the Montreal area was performed during the months of June and late August/September 2006 and January 2007. Processes at these plants include coagulation and flocculation, sand filtration, ozonation and disinfection by chlorine. To test the variation in endotoxin concentrations during a sand filter cycle, samples were withdrawn directly from a filter in one of the treatment plants studied. The filtration cycle, from one backwash to the next one, lasts 72 h. Samples were collected immediately before the backwash, at the beginning and at the end of the ripening period, at the beginning of the filtration cycle and 48 h later, which corresponds to a half cycle period.
Of the two endotoxin detection methods used, LAL consistently gave slightly higher values compared to rFC; rFC also required more expensive hardware, but the method was less tedious and reagent costs were lower. Results presented, unless otherwise stated, were obtained with the rFC method. Endotoxin levels decreased in raw water samples between June and September. Concentrations ranged from 20 to 30 EU/mL in June, and decreased to 10 to 14 EU/mL in August and beyond. For the disinfection processes, the UV and free chlorine doses tested had little or no effect on the endotoxin concentrations, but ozone reduced the concentrations by up to 75%. Sand filtration and flocculation showed significant endotoxin removal efficiencies (50--60%). Levels remained around 5 EU/mL throughout the remaining treatment processes regardless of the influent concentration. Hence, endotoxin inactivation by free chlorine and UV does not occur with typical doses used in drinking water treatment plants; in contrast, flocculation and sand filtration, as well as ozonation, are much more effective.
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Hou, Ting. „DNA microarray-based detection of water-borne viruses“. Thesis, University of Surrey, 2007. http://epubs.surrey.ac.uk/2165/.
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Viruses can be transmitted through and contaminate waters causing waterborne epidemics to humans and animals. There is insufficient understanding about how viruses survive in the environment, and to what extent this may differ between agents or in the co-presence of other micro-organisms. The limited data makes it difficult to determine the risks of viruses and this hinders the preparation of preventative plans against viral transmission through the waters. This project sought to establish a DNA microarraybased approach to detect and differentiate between viruses in environmental waters, to provide a sensitive, specific and rapid system for monitoring virus contamination. Such a system might provide data not only for improved predictions of the outbreak of diseases but may lead to the effective modelling ofvirus re-circulation through the environment. The Picornaviridae virus family was the focus of this project. 152 specific microarray probes were designed after using 'ClustalX' software to multiply align the respective virus sequences and conducting 'BLASTN' similarity searches to estimate their specificity. Standard and multiplex RT-PCR amplification of viral nucleic acids with direct incorporation of fluorescent Cy-dyes was combined with the DNA microarray hybridization technique to identify the virus composition of test and environmental samples. The microarray data was normalised and ranked using a range of statistical methods. After the development of appropriate detection criteria using pilot studies with known input virus samples the experimental and statistical process was applied to detection and identification of viruses within environmental samples. Following tests on a range of different techniques for RNA extraction, amplification and labelling the following optimal procedure was adopted: following the concentration of virus particles by acetone precipitation, RNA from the environmental samples was extracted using the 'QIAamp Viral RNA Mini Kit'; following olio-dT-primed cDNA synthesis, the 'Genomiphi V2 DNA Amplification Kit' was used to randomly amplify the cDNA; the DNA was then directly labelled by incorporating Cy-dyes in a PCR reaction with multiple virus-specific primers. A sewage sample was provided by the Reading HPA Environmental Virology Unit for testing in this project; they had identified a number of viruses in this sample by cell culture: Coxsackieviruses B2, B3, B4 and B5 and also detected some unknown isolates. The optimised microarray-based method developed in this project predicted the presence of the following viruses in the same sewage sample: Coxsackieviruses B4 and B3, Bovine Enterovirus, Poliovirus and Hepatitis A virus. Thtis, while some ofthe same viruses were detected by the microarray, a range of other viruses were also detected, using relatively stringent statistical thresholds. The microarray-based detection system appears to have broader specificity, and possibly sensitivity, than the cell culture-based approaches and importantly, is potentially able to direct non-cultivable and non-viable viruses in a water sample. These findings, coupled with the rapid nature of the technique, suggest that micorarrays, could, in the future, provide a superior alternative to cell culture-based methods for detection ofwaterborne viruses.
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Kallingalthodi, Hari. „Cavitation Detection In a Water Jet Propulsion Unit“. Thesis, University of Canterbury. Electrical and Computer Engineering, 2009. http://hdl.handle.net/10092/4438.
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Various sensing and digital signal processing approaches to detect cavitation in a water jet propulsion unit were examined based on results in the literature. Several commercially viable sensors were evaluated based upon their ability to detect the cavitation phenomenon, cost, and robustness. An algorithm has been implemented and tested against data recorded from the candidate sensors. The combination of vibration and pressure sensors and the algorithm appear promising and a path for further development and testing is available to Hamilton Jet.
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Li, Wenhua. „Channel response and target detection in shallow water“. Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/42573.
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Enriquez-Enriquez, Carlos. „Detection and survival of selected viruses in water“. Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186948.
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Nucleic acid hybridization (gene probe) and polymerase chain reaction (PCR) techniques have been used to detect viral nucleic acid in water. However, gene probe and PCR may not distinguish between infectious and noninfectious viruses. This study evaluated the ability of gene probe to detect viable poliovirus 1 (polio 1), from sterile and nonsterile groundwater, and the ability of PCR to detect infectious human immunodeficiency virus (HIV-1) from tap and wastewater. The plaque forming (BGM cells), and the tissue culture infectious dose fifty (TCID₅₀) (PLC/PRF/5 cells) procedures were used to detect infectious polio 1 and HIV-1, respectively. Detection of polio 1 by gene probe and cell culture was similar in nonsterile water and in filter sterilized water, but not in autoclaved water. These results suggest that in some natural waters, detection of polio 1 by gene probe may correlate to detection by cell culture procedures. Although detection of infectious HIV-1 by cell culture decreased gradually, until no virus could be found, detection by PCR remained positive throughout the study. Therefore, it was concluded that the use of PCR to assess the risk associated to the presence of HIV-1 in polluted waters, may not be adequate. The enteric adenovirus types 40 (Ead 40) and 41 (Ead 41) are considered the second most important cause of viral gastroenteritis in children, but their role as waterborne pathogens is uncertain. This study compared the survival of Ead 40 and Ead 41 with polio 1, and hepatitis A virus (HAV) in different types of water. The Enteric adenoviruses survived longer in tap and sea water than either polio 1 or HAV, but only slightly better in wastewater. These results suggest that the enteric adenoviruses may survive for prolonged periods in water, representing a potential route of transmission. This study evaluated also the concentration of Ead 40 by the filter adsorption-elution method. With negatively-charged filters, recovery efficiencies of 22, 36, and 38% were obtained from secondary sewage, tap and sea water, respectively. Using electropositive filters, Ead 40 was recovered from tap water with an efficiency of 26.5%. These results show that Ead 40 can be concentrated, from water, with an efficiency comparable to that of other enteric viruses.
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Goh, Jung Hean. „Real time water pipes leak detection using electromagnetic waves for the water industry“. Thesis, Liverpool John Moores University, 2011. http://researchonline.ljmu.ac.uk/6013/.
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This project concerns the use of an electromagnetic sensor for the detection of leaks/cracks in water pipes. As old metal pipes corrode they start to become brittle, resulting in the potential for cracks to appear in the pipes. In addition corrosion can build up resulting in a restricted flow of water in the pipe. Using an electromagnetic (EM) wave sensor to monitor the signal reflected from the pipes in real time, provides the necessary information to determine where a leak in the pipe has occurred. Analysis of the reflected signal can provide the operator with information about the condition and position of a leak within the pipe. This is the first time research has been carried using EM waves for leak detection in water pipelines. This project involves the design and construction of an EM sensor operating at frequencies in the range of 240MHz to 560MHz, and at a power of OdBm. The sensor is launched into the water pipeline through any existing hydrant and is moved along the pipeline to check for leaks. The simulation software High Frequency Structure Simulator (HFSS) was used to model the pipe section as a circular waveguide cavity, and also for antenna simulation. The monopole and loop antenna were designed to determine the best antenna for this project. The printed circuit board (PCB) design package Eagle was used to provide the surface mount layout for the sensor, and the PCB board was fabricated by using a computer numerical control (CNC) routing machine. Finally the graphical interface package LabVIEW was used to control the frequency sweep for the sensor and to capture the data from the sensor. Based on the findings of this project, the EM wave sensor could be used to determine a leak up to a 0.9 correlation limit using low cost RF electronic devices.
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Du, Preez Martella. „Development of novel seminested polymerase chain reaction assays for detecting toxigenic Vibrio cholerae and Shigella spp. in water“. Diss., University of Pretoria, 2001. http://hdl.handle.net/2263/26893.
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Young, Toby Edward. „Water-only chemical analysis methodologies : investigations of water liquid chromatography, subcritical water extracton, and dynamic surface tension detection /“. Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/8528.
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Tandon, Puja. „Detection and enumeration of faecal indicator bacteria in water“. Thesis, Northumbria University, 2006. http://nrl.northumbria.ac.uk/1133/.
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This study investigated the effects of various factors, namely exposure to brass/copper, sunlight, high temperature, chlorine, low pH, or starvation, on the enumeration of faecal indicator bacteria in water, performed using non-selective & selective media under conventional aerobic conditions & under conditions designed to neutralise reactive oxygen species e.g. by the addition of 0.05% w/v sodium pyruvate as a scavenger of peroxides &/or anaerobic incubation, to encourage fermentative metabolism. These methods were compared with standard US & UK methods for the recovery of injured bacteria. The information gained was used for the development of a novel broth-based medium for the enumeration of sub-lethally injured Escherichia coli under field conditions. The novel broth-based field medium ('Coliblack') was tested against a currently used method (H2S test) & evaluated under field conditions with unskilled personnel in rural locations in India. The results showed that growth conditions designed to neutralise reactive oxygen species could enhance the colony count of faecal indicator bacteria, whether enumerated using a non-selective medium, a selective medium, a resuscitative medium, or a chromogenic growth medium, following exposure to stressors such as storage of water in a brass container, sunlight, high temperature & chlorine. Such conditions may induce sub-lethal injury in E. coli & E. faecalis, inactivating the bacterial cells under conventional aerobic enumeration conditions as a result of their oxygen-sensitivity. However, exposure to some other stressors namely low pH & starvation was not strongly oxygen-sensitive, as no substantial differences between counts were observed on various growth media or enumeration conditions. The results from enumeration experiments were used to develop a field-based broth medium with a peroxide-neutralising resuscitative agent (sodium pyruvate), a selective agent showing minimum inhibition (Tergitol 7) & a chromogenic diagnostic agent based on defined substrate technology (8 hydroxyquinoline-glucuronide). The Coliblack medium indicates the presence of Escherichia coli in the drinking water by a colour change of the medium to black. Furthermore, the preliminary trial carried out for the evaluation of the novel broth-based field medium gave positive feedback from users. In this respect the results obtained in the present study represents an advancement in understanding of how to maximise the enumeration of faecal indicator bacteria in water & how to apply this information to improve detection under field conditions.
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Hodgkinson, Jane. „Photoacoustic and photothermal detection of trace compounds in water“. Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244982.
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Choi, Changrak. „Robot design for leak detection in water-pipe systems“. Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/70434.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 113-116).
Leaks are major problem that occur in the water pipelines all around the world. Several reports indicate loss of around 20 to 30 percent of water in the distribution of water through water pipe systems. Such loss of water represents critical waste of valuable resources, especially in countries such as Saudi Arabia where water is scarce. Moreover, leaks provide pathways for outside contaminants to enter into water pipe system which can deteriorate the quality of water and pose health risks to those drink from it. Considering these negatives, the importance of detecting where the leaks occur within vast network of water pipe system cannot be overemphasized. Further, for accurate and effective detection of the leaks, an in-pipe approach is taken which differs from previous detection methods. This thesis is on the design of mobile robotic platform that carries the necessary sensor and travels inside the water pipe systems. To begin with, experiments were carried out to investigate the suitability of using acoustic sensor to detect the leaks and favorable results were obtained. Then design specification of the mobile robotic platform that will carry the sensor is discussed with brief description of each components of the robot given. As components for the mobile robotic platform, a rigid-flexible robotic joint is developed that enables the robot to travel through bends and turns. Further, a novel braking mechanism using permanent magnet is presented. The mechanism results in a friction controllable leg that can be used to slow down and control the speed of robot in the presence of water flow. Finally, possible candidates for propulsion unit are discussed and evaluated with guidance for future work to be progressed.
by Changrak Choi.
S.M.
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Sushko, O. A., О. М. Bilash und M. M. Rozhitskii. „Nanophotonic method for polycyclic aromatic hydrocarbons detection in water“. Thesis, ISE, 2012. http://openarchive.nure.ua/handle/document/8866.
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Polycyclic aromatic hydrocarbons (PAHs) are the widespread environmental contaminants that can be found in atmosphere, water, soil, sediment and organisms. Among most dangerous PAHs is benzo[a]pyrene (BP). The effects of BP on health are: short-term when people are exposed to it at levels above the maximum contaminant level (MCL) (0.2 ppm) for relatively short periods of time leading to red blood cells damage, anemia ect; suppression of immune system and long-term, when human beings are exposured do BP influence at levels above the MCL namely effects on reproducibility and high probability of cancer illnesses.
There are known methods for PAHs detection, such as chromatography, immuno-chemistry, biological and chemical ones. However, they have several disadvantages, including high cost, duration and complexity of the analysis procedure, the high detection limit and low selectivity. So at present a development of a new method of PAHs detection based on modern technologies and materials such as nanotechologies and nanomaterials. Belonging to above mentioned is nanophotonic method of PAHs assay.
Nanophotonic method for PAHs detection in particular BP in water is a combination of electrochemical and electrochemiluminescence analysis with the application of nanomaterials and nanotechnologies. This method can be carried out using nanophotonic sensor based on nanomaterials such as semiconductor quantum dots (QDs).
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Sushko, O. A., О. М. Bilash und M. M. Rozhitskii. „Nanophotonic method of organic carcinogens detection in water objects“. Thesis, Technische Universität Ilmenau, 2012. http://openarchive.nure.ua/handle/document/8867.
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Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental agents commonly believed to contribute significantly to human cancers pathologies. PAHs are formed in the process of incomplete combustion of organic material and are found widely in the environment, for example, in water, food, soil etc. so human exposure to PAHs is unavoidable. Like many other carcinogens, polycyclic aromatic hydrocarbons are metabolized enzymatically to various metabolites, of which some are highly reaction active. One of the most dangerous organic PAHs carcinogens is benzo[a]pyrene (BP). There are known methods for PAHs detection in water objects, such as chromatography, immuno-chemical, biological and chemical ones. However, they have several disadvantages, including high cost, duration and complexity of the analysis procedure, high detection limit, low selectivity and some others. So at present a development of new methods of PAHs detection based on modern technologies and materials such as nanotechologies and nanomaterials is a rather relevant and important task.
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Saberi, Atefeh. „Automatic outlier detection in automated water quality measurement stations“. Master's thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/25908.
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Des stations de mesure de la qualité de l’eau sont utilisées pour mesurer la qualité de l'eau à haute fréquence. Pour une gestion efficace de ces mesures, la qualité des données doit être vérifiée. Dans une méthode univariée précédemment développée, des points aberrants et des fautes étaient détectés dans les données mesurées par ces stations en employant des modèles à lissage exponentiel pour prédire les données au moment suivant avec l’intervalle de confiance. Dans la présente étude, ne considérant que le cas univarié, la détection de points aberrants est améliorée par l’identification d’un modèle autorégressif à moyenne mobile sur une fenêtre mobile de données pour prédire la donnée au moment suivant. Les données de turbidité mesurées à l'entrée d'une station d'épuration municipale au Danemark sont utilisées comme étude de cas pour comparer la performance de l’utilisation des deux modèles. Les résultats montrent que le nouveau modèle permet de prédire la donnée au moment suivant avec plus de précision. De plus, l’inclusion du nouveau modèle dans la méthode univariée présente une performance satisfaisante pour la détection de points aberrants et des fautes dans les données de l'étude de cas.Water quality monitoring stations are used to measure water quality at high frequency. For effective data management, the quality of the data must be evaluated. In a previously developed univariate method both outliers and faults were detected in the data measured by these stations by using exponential smoothing models that give one-step ahead forecasts and their confidence intervals. In the present study, the outlier detection step of the univariate method is improved by identifying an auto-regressive moving average model for a moving window of data and forecasting one-step ahead. The turbidity data measured at the inlet of a municipal treatment plant in Denmark is used as case study to compare the performance of the use of the two models. The results show that the forecasts made by the new model are more accurate. Also, inclusion of the new forecasting model in the univariate method shows satisfactory performance for detecting outliers and faults in the case study data.
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Jurkevica, Agnese. „Bead-based Immunoassays for Detection of Mircoorganisms in Water“. University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1267625497.
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Tittle, Jacob. „Potable Water Leakage Prediction and Detection using Geospatial Analysis“. Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etd/3663.
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Due to increasing water treatment costs and conservation needs, traditional water loss analysis and acoustic leak detection methods are becoming heavily scrutinized by water utilities. This study explores water loss in Johnson City, Tennessee and how geospatial data analysis techniques improve water loss mitigation. This project uses sample water system pressure data and ordinary kriging spatial interpolation methods to identify leakage areas for further investigation. Analysis of existing geographic information system (GIS) water utility datasets with interpolated hydraulic grade values at sample water pressure points produce manageable survey areas that pinpoint areas with possible water leakage. Field detection methods, including ground-penetrating radar (GPR) and traditional acoustic methods, are employed to verify leakage predictions. Ten leakage areas are identified and verified using traditional acoustic detection methods, work order research, and GPR. The resulting data show that spatial analysis coupled with geospatial analysis of field pressure information improves water loss mitigation.
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Kuwahara, Sara Sadae. „Quantum Dot Applications for Detection of Bacteria in Water“. Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/193744.
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Semiconductor nanocrystals, otherwise known as Quantum dots (Q dots), are a new type of fluorophore that demonstrates many advantages over conventional organic fluorophores. These advantages offer the opportunity to improve known immunofluorescent methods and immunofluorescent biosensors for rapid and portable bacterial detection in water. The detection of the micro organism Escherichia coli O157:H7 by attenuation of a fluorophore’s signal in water was evaluated alone and in the presence of another bacterial species. A sandwich immunoassay with antibodies adhered to SU-8 as a conventional comparison to our novel attenuation detection was also conducted. The assays were tested for concentration determination as well as investigation for cross reactivity and interference from other bacteria and from partial target cells. In order to immobilize the capture antibodies on SU-8, an existing immobilization self-assembly monolayer (SAM) for glass was modified. The SAM was composed of a silane ((3-Mercaptopropyl) trimethoxysilane (MTS)) and hetero-bifunctional cross linker (N-γ-maleimidobutyryloxy succinimide ester (GMBS)) was utilized in this procedure. The SU-8 surface was activated using various acids baths and oxygenated plasma, and it was determined that the oxygenated plasma yielded the best surface attachment of antibodies. The use of direct fluorophore signal attenuation for detection of the target E. coli resulted in the lowest detectable population of 1x10¹ cfu/mL. It was not specific enough for quantitative assessment of target concentration, but could accurately differentiate between targeted and non-targeted species. The sandwich immunofluorescent detection on SU-8 attained the lowest detectable population of 1x10⁴ cfu/ml. The presence of Klebsiella pneumoniae in solution caused some interference with detection either from cross reactivity or binding site blocking. Partial target cells also caused interference with the detection of the target species, mainly by blocking binding sites so that differences in concentration were not discernable. The signal attenuation not only had a better lowest detectable population but also had less measurement error than the sandwich immunoassay on SU-8 which suffered from non-uniformed surface coverage by the antibodies.
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Tijunelyte, Inga. „Development of SERS nanosensor for detection of water pollution“. Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCD007/document.
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La pollution des eaux par des composés organiques constitue un problème mondial majeur. Parmi cescomposés, les molécules aromatiques de faibles masses molaires constituent une famille largementrependue dont la toxicité et la cancérogénicité est avérée et bien documentée. La Directive-CadreEuropéenne sur l’eau (2000/60/EC, 2006/118/EC and 2006/11/EC) établit des normes de qualitéenvironnementales ayant pour objectif d’améliorer la qualité des eaux. Dans ce contexte, ledéveloppement d’outils analytiques robustes, permettant de détecter et de quantifier précisément et insitula présence de polluants dans les eaux est d’une importante primordiale. L’objectif principal de cetteétude est l’élaboration de nanocapteurs sensibles, robustes et réutilisables, permettant l’analyse depolluants organiques dans les eaux grâce à la Spectroscopie Raman Exaltée de Surface (SERS).Tout d’abord, une attention particulière a été portée à la sélection des récepteurs et des différentesstratégies de fonctionnalisation permettant d’élaborer un nanocapteur SERS capable de pré-concentrerles polluants visés. L’utilisation d’antigènes et de fragments d’antigènes (F(ab)2) a montré des résultatsprometteurs pour l’élaboration de nanocapteurs très sélectifs. Une seconde approche basée surl’utilisation de cavitants ou molécules hôtes, telles que les cyclodextrines (CDs), a été développée. Lapré-concentration sélective des polluants grâce à leur taille a été démontrée par spectroscopie Raman etSERS. Enfin, grâce à la possibilité d’identification moléculaire en milieu complexe offerte par laspectroscopie SERS, une approche permettant une pré-concentration non spécifique des polluants a étédéveloppée. Pour ce faire, différents sels de diazoniums (DSs) ont été synthétisés et greffés à la surfacedes nanocapteurs afin de créer une couche hydrophobe permettant la pré-concentration et la détection decomposés apolaires. Les performances de ces nano-capteurs ont été démontrées pour la détection de plusieurs PAHs apolairesEnvironmental water pollution by organic compounds is in continues worldwide concern. Low molecular mass aromatic molecules consisting in benzene rings have received considerable attention due to a documented significant toxicity and carcinogenicity. Within the objectives of the European Water Framework Directives (2000/60/EC, 2006/118/EC and 2006/11/EC) aiming in water quality improvement, the development of analytical tools allowing in-situ accurate and sensitive detection is of primary importance and would be a meaningful innovation. With this regard, the main scope of this study was to design sensitive, reproducible, specific and reusable nanosensor for the detection of organic pollutants in environmental waters using Surface Enhanced Raman Spectroscopy (SERS).During this study the main attention was paid to the selection of suitable receptors and strategies for SERS nanosensor surface functionalisation in order to preconcentrate targeted pollutants. The application of antibodies and antigen binding fragments (F(ab)2) for surface decoration was found to be promising approach for highly selective nanosensor design. Another strategy exploited during this study was related with an application of cyclodextrins (CDs). Using Raman and SERS spectroscopies the size selective encapsulation of analytes was demonstrated. Finally, taking advantage of molecular identification in the complex environments offered by SERS technique, nanosensors providing non-specific molecular pre-concentration was considered. For this purpose several diazonium salts (DSs) were studied and applied to the surface functionalisation to create highly hydrophobic coating layer. The performance of such nanosensor was evaluated by detection of aromatic pollutants
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Barrett, Brian Edward. „Water-borne geophysics for Murray River salt-load detection“. Title page, contents and abstract only, 2003. http://web4.library.adelaide.edu.au/theses/09SM/09smb2741.pdf.
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Includes bibliographical references (leaves 112-115) Towed DC Resistivity and Transient Electromagnetic arrays have been trialled for suitability in monitoring salt-loads on the Murray River at Waikerie, South Australia.
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Sellwood, Jane. „Studies on enteric viruses in water and sewage“. Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314325.
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Coyle, Sadie Marie. „Investigations of microcystins (cyanobacterial peptide toxins) : detection, purification and analysis“. Thesis, Robert Gordon University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360091.
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Farah, Elias. „Detection of water leakage using innovative smart water system : application to SunRise Smart City demonstrator“. Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10103/document.
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Le travail de thèse porte sur l'utilisation des réseaux d’eau potable intelligents pour la détection des fuites. Il s’inscrit dans le cadre du projet SunRise qui vise à transformer la Cité Scientifique de l’Université de Lille en une ville intelligente et durable. Le campus représente une petite ville de 25000 habitants. Ce travail fait également partie du projet européen SmartWater4Europe, qui vise à développer 4 démonstrateurs des réseaux d’eau intelligents. Le travail comporte 5 parties. La première partie comprend une étude bibliographique sur les technologies pour la détection des fuites. La deuxième partie présente le démonstrateur SunRise Smart City, qui sert de support pour cette thèse. Cette partie détaille les instrumentations installées dans le site et les tests de simulation des fuites pour analyser l’efficacité d’un système acoustique de détection des fuites. La troisième partie comporte une analyse de consommation d’eau à différentes échelles pour les sous-compteurs et les compteurs généraux. Cette analyse est menée à l’aide d’une plateforme développée pour faciliter l’agrégation et l’interprétation des données. Cette partie présente aussi les fuites majeures en 2015. La quatrième partie concerne la détection des fuites en se basant sur le bilan d’eau. Elle présente aussi la stratégie du Contrôle Actif des Fuites (CAF) appliquée sur le site afin de réduire le niveau de l’Eau Non-Vendue (ENV). La dernière partie comporte l’application des méthodes avancées pour la détection des fuites. Ces méthodes comprennent l’approche CFPD ‘Comparison of Flow Pattern Distribution’, la méthode du Débit Nocturne Minimal (DNM) et deux approches statistiques développéesThis work concerns the use of the Smart Water Technology for the detection of water leakage. It is a part of SunRise project which aims at turning the Scientific Campus of the University of Lille into a large scale demonstrator site of the "Smart and Sustainable City". The campus is representative to a small town of 25000 inhabitants. This work is also a part of the European Project SmartWater4 Europe, which aims to develop 4 demonstrators of the Smart Water Technology. This thesis includes five parts. The first part includes a literature review concerning the technologies used in leakage detection. The second part presents the SunRise Smart City demonstrator, which is used as a basis for this thesis. This section details the instrumentation installed in the demo site as well as leak simulations tests to analyze the efficiency of an acoustic system of leakage detection. The third part focuses on the analysis of the water consumption at different time scales. Analysis concerns both sub-meters and bulk meters. It is conducted using a platform for the aggregation and the interpretation of the data. This part presents also major leakage events in 2015. The fourth part concerns leak detection using the water balance calculation based on the top down and bottom up approaches. It also presents the Active Leakage Control (ALC) strategy applied to the demo site in order to reduce the level of Non-Revenue Water (NRW). The last part concerns the use of advanced methods for leak detection with application on the campus data. These methods include the Comparison of Flow Pattern Distribution Method (CFPD), the Minimum Night Flow (MNF) method and two developed statistical approaches
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Thomas, Bruce Carleton University Dissertation Geography. „Visual interpretation of thematic mapper imagery for the change detection of wetlands in eastern Ontario“. Ottawa, 1988.
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Mwila, Katayi. „Rapid enzymatic detection of organophosphorous and carbamate pesticides in water“. Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1004084.
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The increased use of pesticides has resulted in a corresponding increase in concern for the effect they may have on the health of humans and other non-target organisms. The two main areas of concern are the toxicological effects that mixtures of pesticides may have as well as the endocrine disrupting effects. Although the individual pesticides may be present at concentrations below the levels deemed to be detrimental to health, it has been argued that their combined effect may still result in elevated health risks. Another important aspect of pesticide risk assessment requires a consideration of the breakdown products of pesticides and their effect on human health. There has been very little research into the effects of degradation products and this issue should be addressed as these could potentially pose a higher risk than their parent compounds. One of the most important bio-markers available for use is the ubiquitous enzyme acetylcholinesterase (AChE). This enzyme is responsible for one of the most important functions in the body; namely nerve impulse transmission, upon which all life depends. The inhibition of this enzyme indicates toxicity and as a subsequence, a threat to the organism’s well-being. Bioassays have also recently been developed to test chemicals for endocrine disrupting effects. These tests rely on a dose response equivalent to that of the most potent well known estrogen 17-β estradiol. Any chemical that has a measurable response is deemed to display endocrine disrupting effects. This first aim of this study was to investigate the toxicological and endocrine disrupting effects of three organophosphorus pesticides; aldicarb, parathion and demeton-S-methyl, in addition to two breakdown products; aminophenol and p-nitrophenol. Two carbamate pesticides; carbaryl and carbofuran were also analysed. The toxicological effects of mixtures of the parent pesticide compounds were tested to assess if any antagonistic, additive or synergistic effects were observed. This data was then used in conjunction with an artificial neural network to assess if individual pesticides could be distinguished from mixtures of pesticides. A final objective was to sample various Eastern Cape water sources, utilising the enzymatic assay to determine the presence of any of these pesticides in these samples. There were several conclusions drawn from this study. AChE was successfully used as an assay to test the toxicity of the pesticides under investigation, based on their inhibition of this enzyme. An important factor for consideration throughout the study was the need to establish basal and monitor AChE activity (i.e. the need to monitor AChE activity in the absence of any pesticide). This ensured accurate comparison of the results obtained. It was found that demeton-S-methyl was the most potent of these pesticides followed by carbaryl, parathion, aldicarb and finally carbofuran, and that carbofuran could potentiate AChE. The results indicated that pesticide mixtures generally exhibited an additive inhibitory effect on AChE, although at some concentrations of pesticides, synergistic and antagonistic effects were noted. From the data using mixtures of pesticides, a feed forward neural network was created that was successfully able to distinguish individual pesticides from mixtures within its training parameters. None of the pesticides tested displayed endocrine disrupting properties in the Yeast Estrogen Screen (YES), T47D-KBluc and MDA-kb2 bio-assays. Other studies reported mixed results in this regard and thus no final conclusions could be drawn. The Blaauwkrantz River, Kariega River, Sundays River, Swartkops River and Kowie River were all tested for pesticides and although positive results were recorded, conventional methods indicated that there were no pesticides in the rivers. There were, however, trace metals present which are known to inhibit AChE, thus causing a false positive result. These results indicated that AChE can be used as a high throughput initial pre-screening tool, but that it cannot serve as a substitute for more accurate conventional testing methods.
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Fiadzomor, Phyllis Aku Yayra. „Trace detection of water vapour by cavity ring-down spectroscopy“. Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492638.
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A continuous wave cavity ring-down (CRD) spectrometer has been developed for the measurement of trace levels of water vapour by absorption spectroscopy at wavelengths m make cavity ring-down spectroscopy potentially more useful than current techniques for measurement of trace water in process gases and vacuum environments of semiconductor manufacture where water vapour contamination has a detrimental effect on the final product.
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Fung, Wai-kit, und 馮偉傑. „Generation and detection of ozone and hydroxyl radicals in water“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31228215.
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Oliver, Jennifer Valerie. „Detection of phenols in water using SPR and specific receptors“. Thesis, University of Kent, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252587.
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Clegg, I. M. „Microwave techniques for the detection of water in crude oil“. Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372184.
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Takir, Driss, Vishnu Reddy, Juan A. Sanchez, Michael K. Shepard und Joshua P. Emery. „DETECTION OF WATER AND/OR HYDROXYL ON ASTEROID (16) Psyche“. IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622751.
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In order to search for evidence of hydration on M-type asteroid (16) Psyche, we observed this object in the 3 mu m spectral region using the long-wavelength cross-dispersed (LXD: 1.9-4.2 mu m) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility. Our observations show that Psyche exhibits a 3 mu m absorption feature, attributed to water or hydroxyl. The 3 m absorption feature is consistent with the hydration features found on the surfaces of water-rich asteroids, attributed to OH- and/or H2O-bearing phases (phyllosilicates). The detection of a 3 mu m hydration absorption band on Psyche suggests that this asteroid may not be a. metallic core, or it could be a metallic core that has been impacted by carbonaceous material over the past 4.5 Gyr. Our results also indicate rotational spectral variations, which we suggest reflect heterogeneity in the metal/silicate ratio on the surface of Psyche.
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Eberhardsson, Elias. „A Visualization Application for Anomaly Detection in Water Management Systems“. Thesis, Luleå tekniska universitet, Datavetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70098.
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Denna rapport beskriver och går igenom processen med att utforma och implementera en applikation för visualisering av data relaterade till vattenhanteringssystem. Datavisualiseringen i fråga är implementerad på en kartvy. Uppgifterna tillhandahålls via Aquaductus sensorenheter vilka placeras i vattenhanteringssystem, dessa för sen regelbundet över data till Aquaductus databas. Applikationen kan både ge en snabb överblick av status över en stor mängd sensorenheter, och är gjord som ett verktyg för att diagnostisera och lokalisera eventuella läckor eller blockeringar. Applikationen är gjord för att användas av kontorsarbetare, som är vana vid verktyg med många, många funktioner och har hög teknisk förmåga. Applikationen ska dock också fungera som ett verktyg för arbetstagare ute på fältet, som använder det på surfplattor eller möjligen mobiltelefoner. Detta breda utbud av tekniska färdigheter och användarmiljöer lägger vikt vid användargränssnittet och att utforma verktyg som kan användas på olika nivåer. Det färdiga verktyget levererar den kraft som behövs, men presenterar den kraften på ett användarvänligt sätt, upprätthållande av designfilosofin. Så levereras användbarhet och flexibilitet, som utlovat.This thesis outlines and walks you through the process of designing and implementing an application for visualizing data related to water management systems. The data visualization in question is implemented on top of maps. The data is provided through Aquaductus sensors placed in water management systems, which relay data periodically. The application is able to both give a quick overview of the status of a large number of sensor-units, and is also made as a tool for diagnosing and locating possible leaks or blockages. The application is made to be used by office workers, who are familiar with tools with many functions and have high technical prowess. The application though, should also work as a tool for workers out in the field, who are using it on tablet devices or possibly smartphones. This wide range of technical skill and user environments puts a high priority on the user interface and designing tools that can be used at different levels of skill. The tools designed gives the users the power needed but presented in a user friendly manner, upholding the design philosophy. Delivering the usability and flexibility promised.
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Shi, Shi-Hui. „General Approach for Electrochemical Detection of Small Molecules in Water“. Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCC276.
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Durant les dernières décennies, grâce à leur application potentielle en diagnostic clinique, en sécurité alimentaire, en sécurité publique et en surveillance environnementale, les capteurs électrochimiques ont été étudiés avec intérêt. Ce travail s'intéresse à la conception et à la fabrication de deux types de capteurs électrochimiques différents. Pour la première stratégie, un biocapteur électrochimique spécifique de l'acétaminophène sans marqueur ni sonde, a été conçu. La stratégie de détection est basée sur la compétition indirecte ; après immobilisation de l'anticorps correspondant sur la surface de l'électrode, en présence de l'antigène l'anticorps se détache de la surface de l'électrode et ainsi génère une augmentation du courant, c'est-à-dire une détection par signal positif. Appliqué à l'acétaminophène, ce biocaptetr électrochimique présente un seuil de détection très bas d'environ lOpm et une sélectivité très importante pour l'acétaminophène comparé à des dérivés proches (aspirine, bisphénol A, pipérazine) même dans un mélange. Dans la deuxième stratégie, un principe de détection basé sur l'affinité et la sélectivité des aptamères (immobilisés sur une électrode d'Au) a été mis au point. En utilisant une cible marquée par une sonde redox, il est possible de quantifier k présence de cible (native) par électrochimie selon un principe d'échange compétitif. Cette nouvelle génération d'aptacapteurs permet le dosage reproductible et rapide (quelques minutes) d'une cible donnée selon un principe de transduction non basée sur le changement de conformatin de l'aptamère lors de la complexation. Ce format est donc aplicable à tout type de ciblesIn the last few decades, due to their potential usefulness in clinical diagnosis, food safety, public security and environmental survey, electrochemical sensors have been intensively investigated. This work mainly focused on the design and fabrication of two different kinds of electrochemical sensors. In the first strategy, we designed an acetaminophen specific reagentless and label-free electrochemical immunosensor. The sensing strategy is based on indirect competitive detection mode; after immobilization of the corresponding antibody onto the electrode surface, in the presence of the antigen, the antibody would be released from the surface and therefore generates a current increase, i. E. "signal-on" detection. Applied to acetaminophen, this electrochemical immunosensor presented a very low detection limit of ca lOpM, (S/N=3) and a very high selectivity towards structural analogs (aspirin, bisphenol A, and piperazine) even in a mixture. In the second strategy, direct competitive detection format was carried out through our novel practical biosensor based on the selectivity and sensitivity of nucleic acid aptamers immobilized onto a gold electrode. The implementation of a competitive exchange scheme, using a target modified by a redox probe, allows targets (e. G. Bisphenol A) to be detected in few min with good reproducibility. Such new aptasensor generation doesn't rely on conformational change of aptamer upon target binding instead and hence, can be adapt to any target of interest
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Sushko, O. A., О. М. Bilash und M. M. Rozhitskii. „Nanophotonic method for polycyclic aromatic hydrocarbons detection in water solutions“. Thesis, Eurosvit, 2013. http://openarchive.nure.ua/handle/document/8870.
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Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental agents commonly believed to contribute significantly to human cancer pathologies. One of the most dangerous organic PAHs carcinogens is benzo[a]pyrene (BP). Like many other carcinogens, PAHs are metabolized enzymatically to various metabolites, some of which are highly reaction active.
Proposed nanophotonic analytical method is based on the process of QDs transfer to ionic forms in an EC process and their subsequent reactions with oppositely charged ionic forms of the analyte – PAHs (BP) inside ECL cell, resulting in the formation of emitter and emission of an analytical optical signal.
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Hansson, Freja. „Detection of Contaminants in Water Using Surface Enhanced Raman Spectroscopy“. Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-85943.
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Due to deteriorating water quality and the world’s increasing demand for clean water, the need for cheap, easy and portable techniques to characterize and quantify pollutants in waters is urgent. Hence, surface-enhanced Raman spectroscopy (SERS) have gained considerable attention in this field. Atrazine and bentazon are two of the most occurring pesticides causing pollution in Sweden, and where therefore examined in this study, along with 4-mercaptopyridine (mpy) as a reference molecule. In this project, silver and gold nanoparticles where synthesised and used as SERS substrates for detection of contaminants in water by using a handheld Raman device provided by Serstech AB. Sodium chloride (NaCl) and magnesium sulfate (MgSO4) where used as aggregation agents allowing the nanoparticles to form hot spots. Mpy was detected to 0.5 nM and an enhancement factor of 108 using silver nanoparticles aggregated with NaCl was obtained. No Raman signal was obtained from atrazine nor bentazon using the handheld Raman device with silver nanoparticles aggregated with NaCl. Therefore the Raman cross-section of the probe molecules where investigated using the handheld Raman device and a conventional Raman device. Bentazon was not detectable using the handheld Raman device but detectable using a conventional Raman device. Atrazine was detectable at high concentrations i.e. atrazine powder using the handheld Raman device and detectable at 100 nM using a conventional Raman device. Since bentazon was not detectable with the handheld Raman device, more focus was put on getting a detectable signal from atrazine using the handheld Raman device. Investigation of the adsorption of atrazine and bentazon to the silver nanoparticle surface was performed. Due to the weaker adsorption to the nanoparticle surface, MgSO4 was used aggregation agent instead of NaCl with mpy, atrazine and bentazon. Mpy was detectable using MgSO4 as aggregation agent, atrazine and bentazon was not. Measurements of mpy, atrazine and bentazon without any salt was performed. For these measurements, no detectable signal from neither molecule was obtained, indicating that the formation of hot spots is necessary to obtained a detectable Raman signal. Measurements of mpy and atrazine with gold nanostars where performed. Enhancement factor using the gold nanostars was calculated to 107, and a detectrable signal from mpy was obtained, not from atrazine. Measurements of atrazine and mpy simultaneously was performed, where mpy peaks was observed but no atrazine peaks. The affinity of the probe molecule and the nanoparticle is crucial to obtain a detectable signal. This study inducates that both the chemical enhancement and electromagnetic enhancement are needed to obtain a detectable signal. For that, strongly binding species is necessary. Considering the simplicity of this method and the limited optimization efforts, there is plenty of room for improvements, including different probe molecules and different SERS substrates. With the right conditions, the evaluated technique reveals a promising and accessible method using a commercially available handheld Raman spectrometer for detection and quantification of contaminants in water.
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McCracken, Katherine E., Trinny Tat, Veronica Paz und Jeong-Yeol Yoon. „Smartphone-based fluorescence detection of bisphenol A from water samples“. ROYAL SOC CHEMISTRY, 2017. http://hdl.handle.net/10150/623041.
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Bisphenol A (BPA), an emerging environmental contaminant and endocrine disrupting compound, has been observed globally in surface water and waste leachates at concentrations that are hazardous to aquatic life and potentially to humans. Limitations in field monitoring on account of the extensive laboratory infrastructure required for standard BPA detection warrants investigation into portable or handheld sensing platforms. In this work, we evaluated a standalone smartphone-based fluorescence sensing method for identifying BPA from water samples. Toward this goal, we demonstrated the novel application of 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) as a fluorescent probe with suitable specificity to BPA compared to functionally and structurally similar hormone and endocrine disrupting compounds. Using this method, bisphenol A was quantifiable through both standard fluorescence spectroscopy and smartphone detection, with an empirical binding constant of K-SV = 2040 M-1 and a direct, unfiltered detection limit of 4.4 mu M from unprocessed samples, suitable for waste leachate and industrial samples. Implementation of further digital image processing and smartphone spectroscopy methods may help to lower this detection limit, bearing promise for future direct detection of bisphenol A from wastewater leachate and environmental samples via smartphones.
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Phillips, Tom. „Detection of Phytophthora cinnamomi from bulk water and soil samples“. Thesis, Phillips, Tom (2008) Detection of Phytophthora cinnamomi from bulk water and soil samples. Honours thesis, Murdoch University, 2008. https://researchrepository.murdoch.edu.au/id/eprint/32595/.
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Miles, Syreeta. „Novel Strategies for the Detection of Pathogens in Drinking Water“. Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/194069.
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To protect public health, detection methods have been developed to monitor drinking water for pathogens. The goal of this dissertation is to evaluate and utilize novel methods that enhances detection and further reduces the risk of waterborne pathogens. The study in Appendix A developed a method to monitor the microbial quality of treated drinking water at the tap utilizing point-of-use (POU) filter. Tap water supplies were monitored in vending machines throughout Southern Arizona using solid block carbon (SBC) filters as a monitoring tool. Out of 48 SBC filters 54.2% were positive for at least one organism. The number of filters positive for total coliforms, E. coli, Enterococci, and enterovirus was 13, 5, 19, and 3, respectively, corresponding to 27.1%, 10.4%, 39.6%, and 6.3% of the total filters. These results suggest that the SBC filter can be used to monitor large volumes of treated drinking water and detect the incidence of indicators and pathogens. The study in Appendix B evaluated the fate of infectious prions in multiple water sources quantitatively utilizing a method that only detects infectious prions. A reduction of PrPˢᶜ was observed at 25°C and 37°C ranging between 0.41-log₁₀ and 1.4-log₁₀ after 1 week. After 8 weeks at 25°C and 37°C, inactivation ranged between 1.65-log₁₀ and 2.15-log₁₀. A maximum rate of inactivation in water occurred at 50°C, ranging from 2.0-log₁₀ and 2.51-log₁₀ after one week. The results from all types of water suggest that dissolved organic matter and temperature influence PrPˢᶜ infectivity. The study in Appendix C evaluated real-time sensors for monitoring microbial contaminants. Most sensor parameters evaluated exhibited an increase in sensor response to an increase in E. coli concentrations. Responses to E. coli concentrations at or below 10³ cfu/mL were very low due to near background levels, and responses to concentrations above 10⁶ cfu/mL exceeded threshold levels for sensors that use light scattering methods due to saturation in the flow cell. The data produced effectively shows that the sensors evaluated could be used to monitor microbial intrusion events in water distribution systems.
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Swiger-Patterson, S., S. R. Piontkowski, Phillip R. Scheuerman und Phillip R. Musich. „Detection of Cryptosporidium and Giardia in a Rural Water Source“. Digital Commons @ East Tennessee State University, 1999. https://dc.etsu.edu/etsu-works/2922.
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Mittmann, Elizabeth(Elizabeth R. ). „Smart water network management with in-pipe leak detection robots“. Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122119.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 85-87).
In this thesis, I created methods and designs to implement smarter, more autonomous water distribution networks (WDNs) and also improved the robots which will travel within the WDN's pipes to better differentiate pipe leaks from bumps in the pipes. Starting from the unit of the in-pipe leak detection robot, I investigated ways to make its soft leak sensors able to differentiate between pulling (due to leaks) and bending (due to bumps), and showed how a new design of adding fabric to the soft sensor allows the sensors to differentiate bending from pulling. Zooming out to the larger picture I looked at feasible ways these robots could be used throughout a cities' WDN, and created cost analyzes to compare futuristic methods of WDN management with current methods of district metered areas (DMAs). However, going from our current state of minimally instrumented pipes, to pipes with many valves to direct in-pipe inspection robots is a big leap, and thus I also created a method to help evaluate the cost trade-off of valve placement and the optimal spots for adding valves in the case where it was ideal to place valves on only some of the intersections of the WDN..
by Elizabeth Mittmann.
S.M.
S.M. Massachusetts Institute of Technology, Department of Mechanical Engineering
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MARINO, Giovanni, Giovanni MARINO und Giovanni MARINO. „Detection of the effects of water stress on woody plants“. Doctoral thesis, Università degli studi del Molise, 2014. http://hdl.handle.net/11695/66250.
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Climate change is increasing the chronic water scarcity in many world regions, and also in Mediterranean basin. Water is the most limiting resource for plant growth and development where the climate is characterized by high potential evaporation and low and highly variable rainfall during the growing season. Water deficit constraints all the physiological processes involved in photosynthesis. In addition, drought and heat have effects on plats secondary metabolism as the synthesis and the emission of volatile organic compounds (VOCs) that, on global scale, are able to influence the chemical and physical properties of the atmosphere. Therefore, in last years has become important to develop methods enabling the detection and the description of water relations and the physiological responses of plants experiencing water stress, that could allow the monitoring on large scale of the effects of an increasing drought condition on the vegetation.
In the present study phenotyping methods have been applied to monitor water relations, photosynthetic status and physiological responses in woody plants experiencing water stress. The aim of the study was to evaluate the reliability of remote sensing techniques, based on the passive analysis of spectral reflectance, to monitor the water status of plants and different functions that are affected by drought. Thereafter, a new application of these methods was tested for the detection of the indirect estimation of foliar isoprenoid emissions, in order to sense them remotely. In addition, the relationships and the interactions of chemical and hydraulic signals from root to leaves and the emission of VOCs were investigated in a partial root zone drought experiment on Populus nigra saplings.I cambiamenti climatici in corso stanno aumentando la cronica scarsità di acqua in molte regioni del mondo, come anche nel bacino del Mediterraneo. L'acqua è la principale risorsa limitante per la crescita e lo sviluppo delle piante, in aree in cui il clima è caratterizzato da un elevato potenziale di evaporazione e precipitazioni scarse e molto variabili nel corso delle stagioni vegetative. Il deficit idrico vincola tutti i processi fisiologici coinvolti nella fotosintesi. Inoltre, la siccità e la temperatura hanno anche effetti sul metabolismo secondario delle piante, come la sintesi e l’emissione di composti organici volatili (VOC) che, su scala globale, sono in grado di influenzare le proprietà fisiche e chimiche dell'atmosfera. Pertanto, negli ultimi anni è diventato di rilevante importanza sviluppare metodi che consentano l'individuazione e la descrizione delle relazioni idriche e le risposte fisiologiche delle piante sottoposte a stress idrico, che potrebbero consentire il monitoraggio su larga scala degli effetti della condizione crescente di scarsa disponibilità idrica sulla vegetazione. Nel presente studio sono stati applicati metodi di fenotipizzazione per monitorare le relazioni idriche, lo stato della fotosintesi e le risposte fisiologiche di piante legnose sottoposte a stress idrico. Lo scopo dello studio è stato di valutare l'applicabilità di tecniche di telerilevamento, basate sull'analisi passiva della riflettanza spettrale, per monitorare lo stato idrico e le diverse funzioni di piante legnose sottoposte a siccità. Successivamente, una nuova applicazione di questi metodi è stato impiegata per la stima indiretta delle emissioni fogliari di isoprenoidi, al fine di consentirne il rilevamento da remoto. Inoltre sono stati studiati, in un esperimento in condizione di parziale siccità della zona radicale in piante in vaso di Populus nigra, i rapporti e le interazioni esistenti tra i segnali chimici e idraulici dalle radici alle foglie e l'emissione di VOC.
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Ruzza, Valentina. „Data assimilation techniques for leakage detection in water distribution systems“. Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3422772.
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Leakage in pressurized water distribution systems is a major issue for water utilities today, because of the huge concerns over public health risks and the economic constraints on energy and resources. This thesis investigates innovative techniques for the detection of leakages in water distribution systems, relying on the calibration of network hydraulic models. The main goal is to suggest a method to reduce the costs of the field surveys currently required from the leakage detection activity on real systems.
An inverse model, based on the coupling between Kalman Filter based data assimilation techniques and network hydraulic models, is proposed and critically analyzed. The model is based on the knowledge of pressure heads, pipe flow rates and volume measurements, which can be easily obtained in any network with a limited effort and no technical troubles, with exception of the flow rate measurements.
The present work investigates different aspects of the proposed coupled model, related to the data assimilation technique used (Ensemble Kalman Filter or Ensemble Smoother), the type of hydraulic analysis developed (demand driven analysis through standard EpaNET or pressure driven analysis), the type of model parameters to be calibrated (the nodal leakage flow rates or the EpaNET emitter coefficients responsible for the nodal leakage flow rates), besides distinctions on the type of assimilated data and on the number and locations of available measurements.
Despite the fact that the success of the proposed technique depends on the specific features and topological structure of the network analyzed, this coupled model applied to synthetic water distribution systems proves to be effective for leakage detection and could be a competitive solution compared to the traditionally used district metering procedures in real world cases.La gestione delle perdite nelle condotte in pressione è una delle più importanti problematiche nei sistemi di distribuzione, per le preoccupazioni riguardo il rischio per la salute pubblica e per i vincoli economici su energia e risorse. Questa tesi intende analizzare tecniche innovative per l'individuazione delle perdite nei sistemi di distribuzione, basandosi sulla calibrazione dei modelli idraulici delle reti. Lo scopo principale è suggerire un metodo per ridurre i costi delle indagini di campo attualmente richieste dall'attività di ricerca perdite su reti reali. Un modello inverso, basato sull'accoppiamento tra tecniche di assimilazione dati basate sul filtro di Kalman e i modelli idraulici delle reti, è proposto ed analizzato criticamente. Il modello si basa sulla conoscenza di misure di pressione, portata e volume, le quali possono essere facilmente ottenute in ogni rete a costi contenuti e senza problemi tecnici, ad eccezione delle misure di portata. Il presente lavoro analizza differenti aspetti del modello accoppiato proposto, relativamente alla tecnica utilizzata per l'assimilazione dati (Ensemble Kalman Filter o Ensemble Smoother), al tipo di analisi idraulica sviluppata (demand driven attraverso la versione standard di EpaNET o pressure driven), il tipo di parametri da calibrare (le portate di perdita ai nodi oppure i coefficienti di emitter responsabili della perdita ai nodi), oltre che alla distinzione sul tipo di dati assimilati e sul numero e sulle posizioni di misura a disposizione. Nonstante il successo della tecnica proposta dipenda dalle caratteristiche peculiari e dalla struttura topologica della rete analizzata, questo modello accoppiato applicato a reti di distribuzione sintetiche si dimostra efficace per l'individuazione delle perdite e può costituire un'alternativa competitiva rispetto alle tecniche di distrettualizzazione correntemente applicate nei casi reali.
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Ruebhart, David Robert. „Alternative Bioassays for the Detection of Cyanotoxins“. Thesis, Griffith University, 2009. http://hdl.handle.net/10072/367103.
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Abstract: The presence of cyanobacteria, and their associated toxins, in drinking water supplies presents a public health risk. When specific cyanotoxins are suspected, analyte specific techniques such as HPLC are generally used. However, if there is a bloom of taxa not previously known as toxic, its potential risk has traditionally been determined by the mouse bioassay. Despite its long standing use, this bioassay has several constraints including a lack of precise quantification of cyanotoxins at low concentrations, insensitivity, difficulties in the interpretation of results and slow turnaround time. Additionally, animal ethics guidelines are calling for the elimination of the use of vertebrates for this application. Thus, the aim of this thesis was to investigate, optimise and validate alternative whole organism bioassays for the detection of cyanobacterial toxicity. As this study was industry funded via the Cooperative Research Centre for Water Quality and Treatment, the potential for research uptake in water industry and other laboratories contracted to undertake routine water quality monitoring, was a guiding factor for research outcomes. The general experimental approach was based on investigating dose-response relationships for selected bioassays tested against cyanotoxins and a variety of cyanobacterial aqueous extracts. It was found that neither the ToxScreen-II Test, a proprietary bioassay employing the bioluminescent test organism Photobacterium leiognathi, nor any of a comprehensive panel of bacteria tested in the disc diffusion bioassay, was sensitive to cylindrospermopsin or microcystin-LR at a maximum concentration of 800 µg/L. The bacteria species tested by disc diffusion technique were also not sensitive to a variety of aqueous cyanobacterial extracts; however, the yeast Saccharomyces cerevisiae indicated selective sensitivity to cylindrospermopsin and an aqueous extract Cylindrospermopsis raciborskii. It was recommended, that future studies of the suitability of S. cerevisiae for detecting cylindrospermopsin, utilise a growth inhibition bioassay utilising a liquid medium with the endpoint measured by photometric determination of turbidity. The importance of the correct taxonomic identification of Artemia species used in the brine shrimp nauplii bioassay was addressed. It was found that Artemia franciscana, not the commonly cited Artemia salina, represented the vast majority of studies in which Artemia was used as an experimental test organism. A validated and optimised A. franciscana nauplii bioassay was reported with maximum sensitivity at 72 h with LC50 values of 0.58 (0.54-0.63) dw µg/mL for cylindrospermopsin and 2.0 (1.8-2.2) dw µg/mL for microcystin-LR. This species was also used to investigate the protective efficacy of the antioxidants vitamin E and Trolox against microcystin-LR. It was revealed that both of these antioxidants offered significant protection against the lethal effect of microcystin-LR. These findings support the use of A. franciscana as a suitable test organism for both the detection of cyanotoxins and as a model for exploring mechanisms of toxicity. It was found, however, that caution should be exercised regarding the importation and free availability of this species because of its invasive potential in Australia. Thus, the native Australian species of brine shrimp Parartemia spp. should be investigated for future bioassay development. An insect bioassay was developed using the globally distributed speckled cockroach Nauphoeta cinerea for the selective detection of Paralytic Shellfish Poison toxicity of an Anabaena circinalis aqueous extract and saxitoxin. This bioassay was found to be tolerant to cylindrospermopsin and microcystin-LR at doses 10 fold greater than the mouse LD50 values while being sensitive to saxitoxin. Likewise, it was found to be tolerant of toxin containing aqueous extracts of C. raciborskii, Microcystis aeruginosa and Nodularia spumigena while being sensitive to A. circinalis. Peak sensitivity of N. cinerea to saxitoxin was 60 min post injection with an ED50 of 31.2 (27.7-35.1) ng/g body weight. As the limits of detection for whole organism bioassays are often considerably higher than the health alert values for cyanotoxins, techniques for sample concentration were considered. The use of passive sampler technology was demonstrated for the sequestration and concentration of cylindrospermopsin and deoxy-cylindrospermopsin with the recommendation that future studies refine this technology and that its use is combined with laboratory bioassays. Both the A. franciscana nauplii and N. cinerea bioassays were deemed as suitable complementary methods for extending the laboratory capacity in commercial laboratories, normally contracted to undertake cyanobacterial monitoring, to include toxicity testing.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Public Health
Griffith Health
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