The aim of this study was to further understand the fouling and cleaning mechanisms of synthetic membranes used to filter an industrially relevant feed. The main focus of this study was to understand the fouling layer properties during pressure driven filtration. A relatively new technique known as Fluid Dynamic Gauging (FDG) was applied to examine the fouling layer thickness. This work comprised of four main themes with overlapping objectives: (i) the optimisation of Spent Sulphite Liquor fouling and cleaning conditions, (ii) the optimisation of molasses fouling and cleaning conditions, (iii) the investigation of the effect of a simple pre-treatment upon the membrane separation performance, and (iv) the application of the FDG in the study of polymeric membranes. An understanding of the mechanisms involved in fouling and cleaning of microfiltration and ultrafiltration membranes used to filter molasses and SSL has been attained. The variables affecting permeate flux and quality were optimised and mechanistic information concerning the synergistic effects between fouling and cleaning was gathered. The application of a simple NaOH pre-treatment was found to affect both the type of foulant species attaching to the membrane surface, and resulted in an altered separation and cleaning performance. Zeta potential measurements, FTIR and AFM demonstrated that both in-pore and surface fouling was present. The data collected indicated that for both membranes evaluated, different fouling species were found to have attached, depending upon the pre-treatment protocol used. These findings are significant, as they offer support to the recommendations made by some polymeric membrane manufacturers that conditioning protocols should include a NaOH step. However, in the SSL system examined, the effect of NaOH pre-treatment resulted in an improvement in the subsequent performance only over the first two or three complete filtration cycles. It is therefore necessary to study membrane systems over multiple fouling and cleaning cycles before a recommendation can be made. An improved understanding of the interaction between the surface chemistry and surface physics during membrane filtration of complex food based material will benefit both membrane manufactures and food industry based users. The technique of Fluid Dynamic Gauging was incorporated into an existing system and validated to monitor the development of cake layers over time. The FDG was also used to optimise conditions and track the thickness of the cake layer during multiple fouling cycles and its removal rate during cleaning, as an aid to understanding removal mechanisms. It has been shown that operating conditions have to be carefully chosen to minimise the effect of membrane fouling. The results show that FDG is a versatile and powerful technique for characterising the dynamics and mechanical behaviour of fouling layers on membrane surfaces. A particular advantage of the FDG technique is its ability to determine the thickness of fouling layers where other techniques would find difficulty. For example, the layers formed in this study were opaque, and consequently the determination of the development of deposit thickness with time would have been very challenging using conventional optical microscopy techniques.

Membrane filtrations are widely used in process industries but are almost always limited by fouling, a highly studied and significant problem. This is defined as unwanted material deposited on a membrane surface or within its pores, which can significantly impair performance and/or reduce operating life. The strategies to mitigate fouling include cleaning in place, modified membranes, and optimisation of operating conditions. In order to correctly select or target improvements to any such measures a detailed mechanistic understanding of the fouling process is important, which requires more than just performance data from unit operations. One key mechanism is that of cake fouling, which describes the build-up of particle layers on the surface of the membrane. Its growth and physical properties are difficult to assess. In this project the technique of fluid dynamic gauging (FDG) has been explored as a means to study cake fouling. This simple, yet robust method allows for estimation of thickness and strength of cake fouling at high concentrations and opacity, without any prerequisite knowledge of feed properties. Studies described herein focused on microfiltrations through cellulosic membranes. FDG was used to track cake growth during filtrations of polydisperse yeast suspensions (which contained large agglomerates), demonstrating its capability to work with non-ideal, food-like substances. Later studies used more predictable suspensions of hollow glass spheres, which were used to assess various filtration models. The most effective was found to be an interpretation of the critical flux laws, which were used to successfully identify pore fouling during filtrations of Kraft lignin, an observation supported by FDG measurements. Another novel achievement of this project was the development of an automated apparatus for performing FDG in cross-flow membrane filtration. This allowed for much faster acquisition of results, and demonstrated the potential for its development into an autonomous system capable of making thickness measurements on the fly during filtrations. The most reliable protocol for determining cake growth rates was by repeated filtrations in which destructive thickness testing was performed at selected time points. This was because continuous or even repeated thickness measurements during a single filtration were found to cause too much disturbance to the fouling layer. Computational fluid dynamics was used to simulate shear stress profiles on the fouling layer, while also providing a more accurate means to calibrate the automated apparatus. Erosion caused by FDG readings, when viewed under a microscope, was found to conform to the shear stress profiles predicted by simulations.

Assessments are fundamental to the process improvement program of any organization in the software industry. Assessments provide a view of the state, capability, and maturity of processes in an organization relative to a reference model. Formal assessments are the most recognized, and are comprehensive in nature. Although the depth of their evaluation often results in significant process improvement opportunities, formal assessments are too costly for frequent use by many organizations. The interim between assessments typically leaves these organizations without the currency of process state information necessary to effectively drive continuous process improvement. Mini-assessments have emerged as a solution. This paper presents a mini-assessment approach that offers a substantial cost reduction compared to formal assessments and satisfies the process state currency requirement. A specification of the approach is given, followed by discussions on the process improvement possible with its use, comparisons to other assessment methods, and an example implementation.

Cette thèse a pour objectif d'apporter une contribution scientifique et technique à la problématique opérationnelle visant l'évaluation de la ressource en eau disponible en période d'étiage. Cet état des lieux constitue en effet un pré-requis indispensable à toute action de gestion destinée à concilier et équilibrer les différents usages à l'échelle du bassin versant. Il est alors essentiel de tenir compte des particularités du milieu en question pour adapter les différents dispositifs de gestion au contexte hydro-climatique local. A cet égard, l'indicateur statistique retenu par la réglementation française pour caractériser l'état de la ressource en période de basses eaux correspond au débit moyen mensuel minimum annuel de fréquence quinquennale sèche (noté QMNA5). Ce dernier constitue donc notre principal objet d'étude. Dans l'idéal, la détermination d'un tel débit de référence requiert néanmoins un suivi des débits en continu sur une période suffisamment longue pour constituer une archive statistiquement exploitable et n'est par conséquent possible qu'au droit d'un nombre limité de stations hydrométriques. Ailleurs il est alors nécessaire de faire appel à des techniques d'estimation que l'on souhaite aussi fiables que possible. Cette problématique offre encore à l'heure actuelle de nombreuses perspectives de recherche auxquelles cette thèse, en s'inscrivant dans la continuité de travaux analogues réalisés ces dernières années aussi bien en France qu'à l'étranger (décennie PUB), tente d'apporter quelques éléments de réponse et de réflexion. Au cours de ces travaux nous nous sommes ainsi donnés pour objectif d'élaborer et d'optimiser, sur la base des techniques existantes, un cadre méthodologique cohérent adapté à l'estimation du QMNA5 et passant notamment par la valorisation de l'ensemble de l'information à caractère hydrologique disponible localement le long du réseau hydrographique, que ce soit sous la forme de jaugeages épisodiques ou de chroniques courtes. Cet effort d'exhaustivité et de synthèse, s'il n'est pas tout à fait novateur, reste assez peu courant et constitue probablement l'un des principaux points forts de ce travail. Parallèlement et quelle que soit l'approche d'estimation envisagée, nous nous sommes constamment attachés à fournir une indication sur la fiabilité de chaque valeur estimée au travers d'un intervalle de confiance. Bien qu'apparaissant comme un critère essentiel pour apprécier la validité des résultats obtenus, la détermination d'une incertitude encadrant les valeurs estimées s'avère le plus souvent négligée dans la littérature scientifique relative à la régionalisation de variables hydrologiques ; cette démarche apparaît ainsi comme le second point fort de ces travaux. Pour répondre à ces objectifs, les modalités optimales d'estimation du QMNA5 ont été identifiées au travers d'une procédure systématique de validation croisée et finalement appliquées pour notamment aboutir à une cartographie nationale du QMNA5 spécifique en tout point du réseau hydrographique. A l'issue de cette application, l'un des résultats présentant sans doute le plus d'intérêt passe par la comparaison des performances d'estimation selon la quantité d'information disponible au site cible. Celle-ci montre bien que la valorisation d'une information hydrologique locale, même très fragmentaire, est susceptible d'accroître de manière significative la fiabilité des estimations obtenues par rapport à une estimation en sites non jaugés. Bien entendu le gain de performance est d'autant plus intéressant que la quantité de données disponible est importante. Ainsi l'exploitation de chroniques courtes apparaît logiquement comme plus avantageuse que la valorisation de données de jaugeages. / Estimating water availability along the river network is a pre-requirement for water management purposes before defining water allocation at catchment scale. In France, rules for water allocation is partly based on QMNA5, the annual minimum monthly flow with a return period of 5 years ; QMNA5 is derived from time series with extended records of natural or naturalized discharges at gauged sites. In most cases, data is not warranted. Three contexts can be identified: (i) gauged site with short records, (ii) site with spot gauging data and (iii) no data available.This thesis aims at developing a general framework for estimating QMNA5 by using all the hydrological data available in the neighbouring of the location of interest (including short discharge records and spot gauging data). Different methods and strategies were adapted to data availability and tested on a large dataset. Their efficiency and sensitivity to the data collection strategy, the definition of neighbouring,… were assessed by cross validation and uncertainties were provided through a confidence interval. Lastly the most efficient methods for deriving QMNA5 are used to draw a national map with estimates along the main river network.In conclusion, one of most significant result can be illustrated by comparing the efficiency of the estimates according to the quantity of information available on the target location. Results show that a significant gain in accuracy in the estimated QMNA5 values, even when using only a few sporadic measurements to supplement regional information. The improvement depends on the amount of available data and the use of short record is logically more advantageous than the valuation of spot gauging data. Nevertheless, spot gauging data may offer obvious advantages in terms of monitoring at locations where embedment of a permanent gauging station is uneasy. Therefore using spot gauging data can be seen as a possible cost-effective trade-off to supply a reliable enough estimation for particular location of interest.

This thesis is devoted to various questions connected with duality. It is composed of two parts.The first part discusses some aspects of timelike T-duality. We explore the possibility of compactification of supergravity theories with various signatures(low energy limit of M-theories which are dual under timelike T-dualities) on parallelizable internal seven dimensional (pseudo-)spheres. We show that, beside the standard theory, only one of the dual theories known as M'-theory can admit such a solution. The effective four dimensional theory is non-supersymmetric and due to the presence of torsion the symmetry of seven dimensional (pseudo-)sphere breaks down to Spin(3, 4). In the second part, in an attempt to have a systematic discussion of gaugings in supergravity, we show the isomorphism between the space of local deformations of the appropriate zero coupling limit of the embedding tensor Lagrangian and that of the second-order scalar-vector Lagrangian, describing the bosonic sector of supergravity ignoring gravity, in a chosen duality frame determined by embedding tensors. We analyze the BV-BRST deformation of a class of scalar-vector coupled Lagrangians, which contains supergravity Lagrangians as examples, and find a set of constraints that guarantee the consistency of the deformations of the Lagrangians. We show in principle that for a large class of theories considered in this thesis, the only deformations are those of the Yang-Mills type associated with a subgroup of the rigid symmetries. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

O objetivo no presente estudo foi avaliar, por meio de tomografia computadorizada cone beam, o transporte do canal, o aumento da área do canal e o desgaste da dentina intrarradicular na região voltada para a furca de molares inferiores com diferentes instrumentos e verificar a influência do desgaste na determinação do instrumento apical inicial (IAI) por meio de MEV. Os dentes foram dispostos (n=10) em três bases de resina (corpos de prova) de acordo com o tipo de preparo cervical e submetidos ao escaneamento em tomógrafo computadorizado de feixe cônico. Em seguida foi realizado o preparo cervical nos canais mesiais G1: Gattes-Glidden 2 e 3 nos canais mesiais e 3 e 4 no distal; G2 LA Axxess 20.06 e 35.06 nos canais mesiais e 35.06 e 45.06 no canal distal. Concluído o preparo do terço cervical os corpos de prova foram submetidos a novo exame tomográfico. O IAI foi determinado inserindo-se passivamente limas tipo K de aço inox, seqüencialmente a partir da lima #10 até obter a sensação de travamento do instrumento no comprimento de trabalho, em seguida este instrumento foi fixado utilizando-se adesivo à base de cianoacrilato para posterior corte apical e observação em MEV. O índice de centralização não mostrou diferença estatística entre os grupos estudados. O aumento percentualda área do canal pós preparo apresentou diferença estatisticamente significante apenas no canal mesio-lingual (p=0,023), o desgaste da dentina intraradicular na região voltada para a furca foi estatisticamente diferente somente na raiz distal. Os resultados mostraram que o percentual médio de ocupação da área do canal pelo IAI não apresentou diferença estatística entre os grupos estudados. Concluiu-se que o desgaste da região de cervical com Gates-Glidden e LA Axxxes não influenciou na determinação precisa do diâmetro anatômico apical nos canais de molares inferiores. / The aim of this study was to evaluate, by means of cone beam computed tomography, the transportation, the increased of the area, and the dentine thickness of the cervical third of the root canal of thirty lower first molars prepared with different instruments and the influence of this preparation to determining the initial apical file to bind (IAI), through scanning electron microscopy. The teeth (n = 10) were fixed on three resin plates (samples) according to the instrumentsused in the cervical preflaring and scanned with a cone beam computed tomography device. Then, preparation was performed in the cervical third of the canals: G1 Gattes-Glidden burs #2 and #3 in the mesial canals and #3 and #4 in the distal canal; G2 - LA Axxess #20.06 and #35.06 in the mesial canals and #35.06 and #45.06 in the distal canal. After preparation, the specimens were submitted to a new CT scan. Each canal was sized using manual K-files, starting with size 08 files, until the working length (WL) was reached. File sizes were increased until a binding sensation was felt at the WL, and the instrument sizewas recorded for each canal. The files were fixed with methylcyanacrylate at the WL. Teeth were then sectioned transversally 1 mm from the apex, with the binding file in the position. The apical region was then observed under a scanning electron microscope. The centering ratio showed no statistical difference between groups; the percentage of area increase after preparation showed statistical significance only in the mesio-lingual canal (P = 0.023); the thickness of the dentine in the region facing the furcation showed statistical difference only in the distal root. SEM analysis showed that the mean percentage area of the IAI in relation to the root canal area at the WL showed no statisticalsignificant difference between groups. It was concluded that cervical preflaring with Gates-Glidden or LA Axxess did not influence the determination of the apical gauging in lower molars.

<p>Denna rapport behandlar en fullständig metod för att följa, associera och klassificera ekospår. Vid radarnivåmätning ska ekon som härstammar ifrån samma fysikaliska objekt följas över tiden och klassificeras. Dagens radarnivågivare löser problemet genom konfiguration. Tankens geometri samt vilka störande objekt som finns anges vid installation.</p><p>Den framtagna metoden har delats upp i tre delmoment. Först binds individuella inmätta ekon samman till linjesegment. Dessa segment associeras samman till ekospår varefter dessa klassas fysikaliskt. Metoden kräver betydligt mindre konfiguration än den lösning som används för tillfället.</p> / <p>In this report a method for target tracking, association and classification of echo tracks in radar level gauges is discussed. In tank gauging echoes from the same physical object are called an echo track. The echoes must be tracked over time and classified. Currently radar level gauge units requires configuration to achieve classifications of echo</p><p>tracks. At installation tank geometry and disturbing echoes has to be registered.</p><p>The method has been divided into three parts. Firstly individual measured echoes are replaced by line segments. Association algorithms then create echo tracks from these segments. The third step is to classify these tracks physically. This method eliminates registering of disturbing echoes.</p>

Denna rapport behandlar en fullständig metod för att följa, associera och klassificera ekospår. Vid radarnivåmätning ska ekon som härstammar ifrån samma fysikaliska objekt följas över tiden och klassificeras. Dagens radarnivågivare löser problemet genom konfiguration. Tankens geometri samt vilka störande objekt som finns anges vid installation. Den framtagna metoden har delats upp i tre delmoment. Först binds individuella inmätta ekon samman till linjesegment. Dessa segment associeras samman till ekospår varefter dessa klassas fysikaliskt. Metoden kräver betydligt mindre konfiguration än den lösning som används för tillfället. / In this report a method for target tracking, association and classification of echo tracks in radar level gauges is discussed. In tank gauging echoes from the same physical object are called an echo track. The echoes must be tracked over time and classified. Currently radar level gauge units requires configuration to achieve classifications of echo tracks. At installation tank geometry and disturbing echoes has to be registered. The method has been divided into three parts. Firstly individual measured echoes are replaced by line segments. Association algorithms then create echo tracks from these segments. The third step is to classify these tracks physically. This method eliminates registering of disturbing echoes.

New millimeter wave interferometric, multifunctional sensors have been studied for industrial sensing applications: displacement measurement, liquid-level gauging and velocimetry. Two types of configuration were investigated to implement the sensor: homodyne and double-channel homodyne. Both sensors were integrated on planar structure using MMIC (Microwave Monolithic Integrated Circuit) and MIC (Microwave Integrated Circuit) technology for light, compact, and low-cost design. The displacement measurement results employing homodyne configuration show that sub-millimeter resolution in the order of 0.05 mm is feasible without correcting the non-linear phase response of the quadrature mixer. The double-channel homodyne configuration is proposed to suppress the nonlinearity of the quadrature mixer and to estimate the effect of frequency stability of a microwave signal source without the help of additional test equipment, at the loss of a slight increase of circuit complexity. The digital quadrature mixer is constituted by a quadrature-sampling signal processing technique and takes an important role in the elimination of conventional quadrature mixer's nonlinear phase response. Also, in the same displacement measurement, the radar sensor with the double-channel homodyne configuration provided a better resolution of 0.01mm, the best-reported resolution to date in terms of wavelength in the millimeter wave range, than the sensor employing simple homodyne configuration. Short-term stability of a microwave signal source, which is an important issue in phase sensitive measurement, is also considered through phase noise spectrum obtained by FFT spectral estimator at Intermediate Frequency (IF). The developed sensors demonstrate that displacement sensing with micron resolution and accuracy and high-resolution low-velocity measurement are feasible using millimeter-wave interferometer, which is attractive not only for displacement and velocity measurement, but also for other industrial sensing applications requiring very fine resolution and accuracy.

The diploma thesis on "A Proposal to Optimize the Distribution Network of Water Level Gauging Stations in South Bohemian Region? deals with the distribution network of gauging stations of a category ?A?, ?B? and ?C? in the catchment area in South Bohemia. The thesis has been designed as an overview of the current situation of the gauging stations in South Bohemian Region; it is focused on the distribution network of these stations not only in the areas hit with floods. It examines whether these critical places across which the stations have been distributed since 2002 correspond to the requirements of the current flood protection, whether it would not be advisable either to increase or, on contrary, to reduce the number of stations in the exposed river areas. The data processed by Povodí Vltavy, Horní Vltava s.p. Plant, and documents by the ČHMÚ were used for the purposes of this examination. The result of the thesis is the fact that the number of the distributed gauging stations is sufficient as for the needs of flood protection, which has been found out by means of structured interviews with the respective experts. Position of these stations has been incorporated in the flood prevention plans and most of these plans have been designed just on the basis of the distribution network of the gauging stations. The critical locations have been sufficiently mapped and recorded and the flood forecasting and warning service uses the gained, very precious information from these gauging stations. The goal of the thesis was to assess the current distribution network of the gauging stations on the rivers in South Bohemian Region. The current distribution network of the gauging stations on the rivers in South Bohemian Region was studied on the basis of an analysis of the ascertained data and documents. The first goal of the examination was the issue whether the current distribution network and the number of the gauging stations correspond to the needs of protection of citizens, cultural heritage, and property, and whether it would not be advisable to increase the number of these stations. The other goal of the thesis was to optimize the gauging stations with respect to the usefulness and their distribution network, whether the distribution network corresponds to the flood protection. The current distribution network of the gauging stations was analysed by means of a partial method of field research, consulting the expert books, legal regulations and a field research. By analysing these data, I tried to find out in the thesis whether optimisation of the number and the distribution network of the water level gauging stations correspond to the current requirements of the gained data from the respective subject-matter authorities. Upon the results of the analysis of the documents, it was found out that the distribution network and optimization of all gauging stations of all categories - ?A, B, C" - meet the needs of the catchment and requirements to their distribution. Upon the gained information, it was found out that Povodí Vltavy and the operators of the gauging stations have created a very clearly organised network. The hypothesis whether the water level gauging stations are distributed on all of the important rivers in South Bohemian Region was disapproved. The gained information suggests that the gauging stations are distributed on all rivers in South Bohemian Region. The research results have revealed that there is a number of locations in danger of big flooding, however, overflowing at such areas does not put in danger people?s lives, health or property. To conclude, it can be said no matter a society is prepared for flooding as best as possible, the nature, namely water, is an element that is to be respected a lot. This is very important in terms of protection of health, life, cultural heritage and property. The thesis will be offered to the water-management authorities and administrators of the location for further use.