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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Study of Nitrogen Removal Rate and Trouble shooting of Pilot plant (ITEST).

Yatham, Venkata Krishna Reddy January 2012 (has links)
This paper is about improving the efficiency of nitrogen and other organic nutrient removal from activated sewage treatment by adopting an innovative technology. The work is to study the changes in nitrogen removal in pilot-scale experiments with the ITEST unit. The report also describes the various sources contributing to the eutrophication of the sea and water, caused by an increase in nutrient levels in different water bodies. Ineffective treatment of sewage contributes to the eutrophication. In the Baltic regions the temperature will be zero (0) or less than zero degree-centigrade during winter season. It results in decreased or fall in temperatures of incoming water to wastewater treatment plants. The temperature is an important parameter for sewage/wastewater treatment processes. Bacteriological nitrification and denitrification is an effective process for removing nitrogen from wastewater. From various research works and articles, it can be found that 23 + / - 2 °C, is the optimum temperature for nitrification and denitrification processes. So, the main aim is to study the effect of maintaining the incoming wastewater temperature by use of heat exchangers on incoming water to an activated sludge process line in pilot plant scale. In the pilot plant there were two testing lines; one line with heating system and the second line without heating system. A temperature of 19 to 20 °C was maintained in the influent to testing line. The nitrogen removal rates were compared between the two lines during the test period of approximately more than 8 months. Other biological activities in the treatment process were also compared between the two lines.
2

Evaluation of underfill-function in HemoCue Monitor, a POCT-instrument

Feldt, Olivia January 2006 (has links)
<p>Objective: The aim of this study was to evaluate a new underfill-function in a POCT-instrument from HemoCue AB (Ängelholm, Sweden). The instrument is in use today among diabetes patients for self-monitoring blood glucose (SMBG). The new function is supposed to guarantee that measuring only will be performed on a sufficient sample volume to assure that the correct glucose value is received.</p><p>Methods and results: Blood samples (whole blood) from 12 patients were analysed with the instrument. Measuring were performed using different volumes in the cuvette. Full cuvette, 3µL, 2µL, 1µL and a measuring on an empty cuvette. The instrument performed measurements on all volumes added to the cuvette except for the empty cuvette. The less sample volume that was used the lower glucose values were reported by the instrument.</p><p>Conclusions: The new under fill-function did not work satisfactory. If such function would be more reliable it would be beneficial for the patient controlling hers/his bloodglucose provided that the testing procedure is being correctly done. This is very important because the results are often used to treat the patient.</p>
3

Evaluation of underfill-function in HemoCue Monitor, a POCT-instrument

Feldt, Olivia January 2006 (has links)
Objective: The aim of this study was to evaluate a new underfill-function in a POCT-instrument from HemoCue AB (Ängelholm, Sweden). The instrument is in use today among diabetes patients for self-monitoring blood glucose (SMBG). The new function is supposed to guarantee that measuring only will be performed on a sufficient sample volume to assure that the correct glucose value is received. Methods and results: Blood samples (whole blood) from 12 patients were analysed with the instrument. Measuring were performed using different volumes in the cuvette. Full cuvette, 3µL, 2µL, 1µL and a measuring on an empty cuvette. The instrument performed measurements on all volumes added to the cuvette except for the empty cuvette. The less sample volume that was used the lower glucose values were reported by the instrument. Conclusions: The new under fill-function did not work satisfactory. If such function would be more reliable it would be beneficial for the patient controlling hers/his bloodglucose provided that the testing procedure is being correctly done. This is very important because the results are often used to treat the patient.
4

Tellurium Speciation Using Hydride Generation Atomic Absorption Spectrometry And In-situ Graphite Cuvette Trapping

Yildirim, Emrah 01 September 2009 (has links) (PDF)
In recent years speciation analysis is becoming more important as it is known that each chemical form of an element behaves differently in biological and environmental media. Since abundance of tellurium in earth crust is extremely low, very sensitive and accurate methods are needed to determine the concentration of tellurium. Hydride generation atomic absorption is a sensitive, fast and economical technique applied for the determination of tellurium. Speciation of tellurium can be achieved by making use of different kinetic behaviors of Te(IV) and Te(VI) upon its reaction with sodiumborohydride. A continuous flow hydride generation system was developed and parameters that affect the analytical signal were optimized. Sample solutions were prepared in 4.0 mol/L HCl / as reductant 0.5 % (w/v) sodiumborohydride in 0.5 % (w/v) NaOH was used. Quantitative reduction of Te(VI) was achieved through application of a microwave assisted prereduction of Te(VI) in 6.0 mol/L HCl solution. Sensitivity of the system was further enhanced by in-situ trapping of the formed H2Te species in a previously heated graphite furnace whose surface was modified using Pd or Ru. Overall efficiency of pyrolytic coated graphite surface was found to be 15% when hydrides are trapped for 60 seconds at 300 oC. LOD and LOQ values were calculated as 86 pg/mL and 287 pg/mL according to peak height values. Efficiency was increased by 46% and 36% when Pd and Ru modifiers were used, respectively. With Ru modified graphite tube 173 fold enhancement was obtained over 180 seconds trapping period with respect to direct ETAAS. LOD values were 6.4 and 2.2 pg/mL for Pd and Ru treated systems, respectively, for 180 s collection of 9.6 mL sample solution.
5

Waste Water Treatment and Optimal Utilization for Irrigation and Biogas Production.

Beereddy, Dinesh Reddy January 2013 (has links)
This paper is about the studies carried out to analyze the feasibility of using an innovative treatment system in the primary treatment process for municipal waste water. Furthermore, experiments are conducted to analyze the optimal parameters for utilizing the treated waters for irrigation purposes and for biogas production from the recovered sludge. The work is carried on the incoming municipal wastewater from Hammarby locality with around 30,000 inhabitants. Chemicals used in this process are, a metal salt namely polymerized aluminum chloride (PAX XL36) and two flocculation chemicals namely, a high molecular weight polymer (HM) (SNF Nordfloc C-192) and a low molecular weight polymer (LM) (Purfix 120). The choice of these chemicals was based on the recommendations made by previous studies on flocculation chemicals. These chemicals aid in flock formation and the DAF unit which provides compressed air, aids in flock flotation. The study is focused on optimizing parameters which implies minimal usage of chemicals and aimed to attain maximum sludge production with best possible treated water quality. All the experiments have been carried out on a pilot scale unit, designed with required specifications and with the foresight to scale up into a large scale unit based on the results. These are obtained by performing a series of analysis specifically formulated for this study. In laboratory experiments were carried out to analyze COD (chemical oxygen demand), Ammonium, Nitrate, Total nitrogen and phosphorus using Dr. Lange cuvettes. As the prime focus is on reuse of the treated water for irrigation purpose and biogas production, all the parameters are modulated in accordance with the standard water quality prescriptions for the water to be used for irrigation. In accordance with the climatic conditions of the region, various parameters are modulated in such a way that in summers the outcome water quality is emphasized and maximization of sludge/organic matter is emphasized during winter season.
6

Bilan hydrochimique et géochimique du Lac Léman

Meybeck, Michel 09 January 1971 (has links) (PDF)
De nombreux points restaient encore imparfaitement étudiés, notamment en ce quî concerne la chimie des eaux et des sédiments du Léman, ainsi que la structure de la cuvette lémanique. De plus, jusqu' ici aucun bilan global du bassin versant du Léman n'avait été entrepris ( en 1970) . Un tel bilan hydrochimique, sédimentaire et géochimique est important pour troîs raisons - le Léman est situé dans un environnement climatique, géologique et géographique qui détermine ses caractères généraux. L'étude des apports permettra donc de connaître la nature des bassins versants et de leur relation avec le lac . - à l'heure où les problèmes d'eutrophisations et de pollutions se posent avec acuité, l'établissement des bilans des lacs est un problème essentiel mais très délicat ,à mettre en oeuvre. enfin du point de vue de la géodynamique externe le bilan d'un bassin versant de 8 000 km2 donne des indications précieuses sur les phénomènes actuels d'érosion et de transport. En ajoutant à ces données celles obtenues pour le Bodensee, nous obtiendrons des résultats ,concernant toute cette partie des Alpes centrales. Notre étude a duré seulement trois ans. Pour un lac comme le Léman, dont le temps de renouvellement des eaux est de l'ordre de 10 ans, cette période est encore insuffisante. Aussi, nous avons été amené à tenir le plus grand compte des échelles de temps et d'espace des phénomènes principaux, afin de présenter un bilan aussi représentatif que possible
7

Metody stabilizace frekvence polovodičových laserů / Methods of frequency stabilization of semicondutor lasers

Kozelský, Adam January 2011 (has links)
The main aim of the thesis is a frequency stabilization of the DFB semiconductor laser diodes. The temperature stability of the laser diode chip, the stability and the noise of the injection current and the backward reflections are the crucial parameters which affects the frequency stability. These influences are described and the resolution is proposed. The theory of the external methods of the frequency stabilization and the comparison of these methods is presented. One method was choosed and this method was realized for 760 and 1540 nm wavelength laser diodes. In this method was used the frequency stabilization based on the linear absorption to the spectral lines of the gases. The diploma work is closed by the measured results of the frequency stability of the used laser diodes and by the comparison of level of stability achieved by the other methods.
8

Transportní procesy v hydrogelech / Transport processes in hydrogels

Sárová, Michaela January 2017 (has links)
This master's thesis is focused on study of transport processes in hydrogels based on humic acids. For this purpose is used methods unsteady diffusion in cuvettes, which was studied the transport of organic dyes, specifically methylene blue and rhodamine 6G, in agarose hydrogel without the addition and with the addition of individual standards humic acids (Leonardite, Elliott Soil, Suwannee River II and Pahokee Peat). This method is based on spectrophotometric monitoring of concentration changes of dyes depending on space of the cuvette and on time. The aim of this thesis was to investigate the effects of interactions between diffusing dye and the particular type of gel to the resultant effective diffusion coefficient of dye. The experiments indicate that the presence of humic acid in the hydrogel greatly affects the transport of selected dyes.
9

Modélisation physique de l’impact du creusement d’un tunnel par tunnelier à front pressurisé sur des fondations profondes / Study of the impact of tunneling with an EPB TBM on the surrounding buildings

Bel, Justin 28 March 2018 (has links)
Le travail de thèse présenté dans ce mémoire vise à analyser et à comprendre les mécanismes mis en jeu au niveau de l’impact du creusement d’un tunnel par bouclier à front pressurisé sur des fondations profondes avoisinantes. Cette thèse a été réalisée dans le cadre du projet européen NeTTUN, au sein du Laboratoire de Tribologie et de Dynamique des Systèmes (LTDS) de l’ENTPE. L’approche phénoménologique conduite lors de ces travaux repose sur deux importantes campagnes expérimentales réalisées à l’aide d’un dispositif unique au plan international de modèle réduit 1g de tunnelier à pression de terre (échelle de l’ordre de 1/10eme). La forte originalité de ce dispositif est de pouvoir simuler de façon réaliste les principales étapes du processus tridimensionnel d’excavation mécanisé d’un tunnel. Dans le cadre de cette thèse, le dispositif existant de modèle réduit de tunnelier a dans un premier temps été reconfiguré afin de pouvoir répondre aux besoins du programme expérimental envisagé. Des modèles physiques de fondations profondes (pieux et groupes de pieux) et de barrières de protection ont été conçus dans le cadre des lois de similitude, fabriqués et instrumentés. Deux campagnes expérimentales d’envergure ont été réalisées en massif de sable sec : l’une concerne les effets du passage d’un tunnelier à front pressurisé sur des fondations profondes avoisinantes (pieux, groupe de pieux), l’autre traite de l’efficacité de barrières de protection (parois moulées) utilisées pour limiter ces effets. Différents paramètres qui influencent l’interaction tunnelier - sol - fondations ont été considérés comme la distance relative tunnel / fondation, la pression frontale de soutènement appliquée par le TBM sur le terrain ou encore la hauteur des barrières de protection. L’analyse phénoménologique menée à l’échelle du modèle concerne en particulier l’évolution des champs de contraintes et de déplacements dans le terrain autour du tunnelier, les déplacements relatifs sol - pieu et sol- barrière, la redistribution des efforts au sein des fondations. L’importante base de données et d’analyse ainsi constituée a été mise à profit pour la validation d’outils de modélisation numérique développés par l’Université de Rome au sein du projet NeTTUN. / The major goal presented in this thesis was to analyze and investigate the mechanisms, which are involved in the impact of the tunnels excavated thanks to an Earth Pressure Balanced Shield on nearby deep foundations. This thesis was realized in European project NeTTUN and the work had been done in the Laboratory of Tribology and Systems Dynamics (LTDS) of ENTPE. During these works, phenomenological approach was based on two important experimental campaigns carried out using a unique device at the international level of a 1g scale model of earth-pressure tunnel boring machine (scale of the order of 1 / 10). The state of the art of this device was to be able to simulate in possibly realistic way the main stages of the three-dimensional process of mechanized excavation of a tunnel. In the framework of this thesis, the existing model tunneling machine device was initially reconfigured in order to reach the expectations of the experimental program envisaged. Physical models of deep foundations (piles and groups of piles) and protective barriers were designed under the similitude laws, manufactured and instrumented. The two large-scale experimental campaigns have been carried out in a dry sand massif. The first one concerned the effects of the passage of a pressurized tunnel boring machine on nearby deep foundations (piles, group of piles), whereas another one dealed with the effectiveness of mitigation procedure (diaphragm walls) used to limit these effects. Different parameters that influenced on the tunneling: soil - foundation interaction considered as the relative tunnel / foundation distance, the frontal face pressure applied by the TBM in the field or the height of the protective barriers. The phenomenological analysis carried out at the scale of the model concerned in particular the evolution of the fields of stresses and displacements in the ground around the tunnel boring machine, relatives pile / soil and wall / soil displacements and the redistribution of stresses along the pile foundations. The large database and analysis constituted was used for the validation of numerical modeling tools developed by the University of Rome within the NeTTUN project.

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