Este trabalho visa estudar as margens necessárias para definir o volume de planejamento do alvo (PTV) requeridas para tratar adequadamente tumores móveis como os localizados na próstata ou tumores localizados em áreas com pouca mobilidade como os da região da cabeça e pescoço, na ausência de localização do alvo por imagem. Também tem como objetivo avaliar o impacto causado pelo PTV, em termos de dose, nas estruturas críticas ao seu redor e sua influência quando planejamento inverso é utilizado na radioterapia com modulação de feixe (IMRT). Dados de 387 pacientes de próstata foram analizados retrospectivamente. Todos os pacientes receberam localização pré-tratamento com ultra-som 2D resultando em 10.327 localizações, cada uma com deslocamento de isocentro em três direções: antero-posterior (AP), lateral direitaesquerda (DE), e superior-inferior (SI). O deslocamento médio e desvio padrão (SD) para cada direção foi estimado a partir dos dados de tratamento gravados diariamente. As incertezas (SD) na posição do alvo foram 4,4 mm (AP), 3,6 mm (DE), e 4,5 mm (SI). O estudo das incertezas no posicionamento diário de 78 pacientes com tumores de cabeça e pescoço que utilizaram máscaras termoplásticas como imobilizadores, avaliados com equipamento de portal com imagem eletrônica (EPID), mostrou variações (SD) na posição do isocentro de tratamento de 3,1 mm (AP), 1,5 mm (DE), 4,5 mm (SI). Aplicando estes desvios num simulador antropomórfico estudou-se os histogramas de dose-volume resultantes do deslocamento do isocentro no tratamento diário. Os resultados mostraram a importância de se colocar margens no volume clínico do alvo para garantir um tratamento adequado e também mostraram que a variação diária do isocentro de tratamento pode causar um aumento de dose maior que o nível de tolerância dos órgãos críticos. / This work intends to study the margins required to define a planning target volume (PTV) for adequate treatment of the mobile tumors such as prostate or those located in areas with less mobility as the ones in head and neck region, in the absence of daily localization imaging based. It is also intends to evaluate the impact caused by the PTV, in terms of dose, to the critical structures surrounding the PTV and its influence when inverse planning is used in the intensity-modulated radiation therapy (IMRT). Data from 387 prostate patients were analyzed retrospectively. Every patient in the study received daily pre-treatment localization with 2D ultrasound resulting in a total of 10,327 localizations, each comprising of an isocenter displacement in 3 directions: anterior-posterior (AP), right-left lateral (RL), and superior-inferior (SI). The mean displacement and standard deviation (SD) for each direction for each patient was computed from daily treatment records. The uncertainties (SD) in the target position were 4.4 mm (AP), 3.6 mm (RL), and 4.5 mm (SI). A study of the uncertainties in the daily positioning of 78 head and neck patients who used thermoplastic mask to immobilize them, evaluated with electronic portal imaging device (EPID), showed variations (SD) in the isocenter treatment position of 3.1 mm (AP), 1.5 mm (RL), and 4.5 mm (SI). By applying these shifts in an anthropomorphic phantom it was studied the dose-volume histograms resultant of the isocenter displacement in the daily treatment. The result showed the importance of putting margins in the clinical target volume to assure an adequate treatment and also showed that isocenter daily variation can cause an increase to the dose greater than the tolerance level to the critical organs.

Este trabalho visa estudar as margens necessárias para definir o volume de planejamento do alvo (PTV) requeridas para tratar adequadamente tumores móveis como os localizados na próstata ou tumores localizados em áreas com pouca mobilidade como os da região da cabeça e pescoço, na ausência de localização do alvo por imagem. Também tem como objetivo avaliar o impacto causado pelo PTV, em termos de dose, nas estruturas críticas ao seu redor e sua influência quando planejamento inverso é utilizado na radioterapia com modulação de feixe (IMRT). Dados de 387 pacientes de próstata foram analizados retrospectivamente. Todos os pacientes receberam localização pré-tratamento com ultra-som 2D resultando em 10.327 localizações, cada uma com deslocamento de isocentro em três direções: antero-posterior (AP), lateral direitaesquerda (DE), e superior-inferior (SI). O deslocamento médio e desvio padrão (SD) para cada direção foi estimado a partir dos dados de tratamento gravados diariamente. As incertezas (SD) na posição do alvo foram 4,4 mm (AP), 3,6 mm (DE), e 4,5 mm (SI). O estudo das incertezas no posicionamento diário de 78 pacientes com tumores de cabeça e pescoço que utilizaram máscaras termoplásticas como imobilizadores, avaliados com equipamento de portal com imagem eletrônica (EPID), mostrou variações (SD) na posição do isocentro de tratamento de 3,1 mm (AP), 1,5 mm (DE), 4,5 mm (SI). Aplicando estes desvios num simulador antropomórfico estudou-se os histogramas de dose-volume resultantes do deslocamento do isocentro no tratamento diário. Os resultados mostraram a importância de se colocar margens no volume clínico do alvo para garantir um tratamento adequado e também mostraram que a variação diária do isocentro de tratamento pode causar um aumento de dose maior que o nível de tolerância dos órgãos críticos. / This work intends to study the margins required to define a planning target volume (PTV) for adequate treatment of the mobile tumors such as prostate or those located in areas with less mobility as the ones in head and neck region, in the absence of daily localization imaging based. It is also intends to evaluate the impact caused by the PTV, in terms of dose, to the critical structures surrounding the PTV and its influence when inverse planning is used in the intensity-modulated radiation therapy (IMRT). Data from 387 prostate patients were analyzed retrospectively. Every patient in the study received daily pre-treatment localization with 2D ultrasound resulting in a total of 10,327 localizations, each comprising of an isocenter displacement in 3 directions: anterior-posterior (AP), right-left lateral (RL), and superior-inferior (SI). The mean displacement and standard deviation (SD) for each direction for each patient was computed from daily treatment records. The uncertainties (SD) in the target position were 4.4 mm (AP), 3.6 mm (RL), and 4.5 mm (SI). A study of the uncertainties in the daily positioning of 78 head and neck patients who used thermoplastic mask to immobilize them, evaluated with electronic portal imaging device (EPID), showed variations (SD) in the isocenter treatment position of 3.1 mm (AP), 1.5 mm (RL), and 4.5 mm (SI). By applying these shifts in an anthropomorphic phantom it was studied the dose-volume histograms resultant of the isocenter displacement in the daily treatment. The result showed the importance of putting margins in the clinical target volume to assure an adequate treatment and also showed that isocenter daily variation can cause an increase to the dose greater than the tolerance level to the critical organs.

A program based on particle tracking velocimetry (PTV) was developed in this work. The program was successfully validated by means of artificial images where parameters such as radius, concentration, and noise were varied in order to test their influence on the results. This program uses the mask cross correlation technique for particle centroid location. The sub-pixel accuracy is achieved using two different methods, the three point Gaussian interpolation method and the center of gravity method. The second method is only used if the first method fails. The object matching algorithm between frames uses cross correlation with a non binarized image. A performance comparison between different particle image velocimetry (PIV) and PTV algorithms was done using the international standard PIV challenge artificial images. The best performance was obtained by the program developed in this work. It showed the best accuracy, and the best spatial resolution by finding the larger number of correct vectors of all algorithm tested. A procedure is proposed to obtain error estimates for real images based on errors calculated with experimental ones. Using this procedure a real PIV image with 20% noise has an estimated average error of 0.1 pixel. Results of the analysis of 200 experimental images are shown for the two best PTV algorithms.

Syftet med detta examensarbete var att utveckla en GC-metod för analys av etylenglykoler i förorenade vattenprover, exempelvis industriavloppsvatten. Detta skulle åstadkommas med en GC-FID och MMI (Multimode Inlet), samt helst utan provupparbetning. Ett annat av målen var att kunna kvantifiera inom området 1 ppm till 100 ppm, och att metoden skulle vara tillräckligt stabil för att kunna ackreditera den.Ett flertal kolonner testades, där en HP-5 med dimensionerna 30 m*0,53 mm*0,88 μm från Agilent var den som gav bäst resultat. Även två olika liners provades, dels en med glasull och dels en 2 mm dimpled liner, där dimpled linern gav bäst resultat, och minst ”carry-over” mellan analyserna. Bland de parametrar som gav störst effekt utmärker sig trycket i injektorn, och tiderna som de olika flödena är igång. För fullständiga inställningar, se bilaga 2.En metod redo för ackreditering hann ej tas fram, det finns ett flertal parametrar som bör undersökas för en effektivare och stabilare analys. Men metoden som är framtagen är redo för omfattande repeterbarhetstest. / The purpose of this bachelor’s thesis was to develop a GC method for analysis of ethylene glycols in polluted water samples, for example industrial sewage water. This was meant to be accomplished with a GC FID and MMI (Multimode Inlet), preferably without sample preparation. One of the goals was to be able to quantify between 1 ppm and 100 ppm, and that the method was stable enough for accreditation.A number of columns were tested, from where a HP-5 with the dimensions 30 m*0,53 mm*0,88 μm from Agilent gave the best results. Also, two different liners were tested, one with glass wool and one 2 mm dimpled liner, where the dimpled liner gave the best results and the least carry-over between samples. Amongst the parameters which gave the biggest effect, the inlet pressure and the different flow times stands out. For a full set of settings, see Bilaga 2.A method ready for accreditation was not developed due to short of time. There are still a number of parameters which should be investigated for a more efficient and stabile analysis. But the method developed is ready for extensive repeatability tests.

Patients with skin lesions of the temple region that have spread to the parotid gland are commonly treated with three-dimensional conformal radiation therapy (3DCRT). 3DCRT has associated limitations when treating this disease. 3DCRT requires this disease site to be treated with two junction regions, resulting in poor dose conformity to the tumour target. Proximity of critical structures to the target volume can make dosimetry difficult, "especially for concave-shaped targets in close proximity to sensitive normal structures" (Saw.C et al., 2002, p76). Intensity modulated radiation therapy (IMRT) is a relatively new treatment technology that has potential to overcome limitations associated with 3DCRT (Garden.A et al., 2004). IMRT has been reported to have significant advantages over conventional 3DCRT treatment, by improving dose to the tumour and lowering doses to critical structures (Adams.E et al., 2001). Research has been conducted into the optimal IMRT treatment for specific head and neck carcinomas. They are identified as class solutions. "A class solution can be defined as the historical experience in designing RT plans for a particular site" (Intensity Modulated Radiation Therapy Collaborative Working, 2001, p913). This study was performed to establish an optimal IMRT class solution for patients with skin lesions of the temple region that have spread to the parotid gland, and to determine if it is the superior treatment option over 3DCRT treatment. Dosimetry planning was performed on computerised tomography data sets of nine patients with this disease site. One optimised 3DCRT dosimetry plan and eight optimised IMRT plans with specific beam arrangements were calculated. Clinical and statistical analysis was performed on; critical structures, conformity indices (CI) and dose volume histogram (DVH) range analysis of the planning target volume (PTV). Analysis of IMRT plans revealed that the 7-beam arrangement and 4-beam ipsilateral arrangement produced significantly lower doses to the majority of critical structures (P < 0.05). The 7-beam IMRT arrangement produced the best and second best CI and DVH PTV results, but these were not significantly different to the majority of other beam arrangements. This indicates that the 7-beam arrangement with defined beam angles of; 40°,120°,160°,200°,240°,300°,0°, is the superior IMRT treatment plan, and thus class solution for this disease site. Clinical analysis confirmed results. Analysis was performed on IMRT class solution results compared with 3DCRT results. CI was significance higher and DVH PTV range was significantly lower for the IMRT class solution (P < 0.05). The class solution delivered significantly higher doses to the majority of critical structures in comparison to the 3DCRT plan (P < 0.05). This indicates that the IMRT class solution is superior to 3DCRT in terms of PTV conformity and homogeneity, but not in terms of doses to critical structures. Skin lesions of the temple region with tumour extension to the parotid gland, is a complicated disease site. Investigations into current and potential radiation therapy treatments will guide treatment options and facilitate outcomes for patients with this disease.

Les barrages sur les rivières sont des obstacles à la migration piscicole. Les passes à poissons sont des ouvrages permettant aux espèces piscicoles de migrer, autorisant le rétablissement de la continuité écologique des cours d'eau. Le but de ce travail est de mieux comprendre les phénomènes physiques présents dans les passes à poissons naturelles. Ces passes sont des canaux à forte pente, équipé de rangées de plots en quinconce. Pour valider la pertinence de l'utilisation d'un modèle numérique, l'étude s'est limitée à l'écoulement autour d'un cylindre émergent placé au centre d'un canal. Le travail est décomposé en deux parties, une expérimentale et une numérique. La partie expérimentale est conduite dans un canal transparent de 4m de long, 0,4m de large et 0,4m de hauteur. Le diamètre du cylindre est 4cm et sa hauteur 20cm (toujours émergent). Les cas étudiés sont des débits de 5, 10, 15 et 20 l/s pour une pente nulle. Les nombres de Froude sont supérieurs à 0,5 et les nombres de Reynolds, basés sur le diamètre, sont compris entre 15000 et 50000. Les écoulements ont été filmés et un algorithme de suivi de particules (PTV) a été développé. Des zones de faibles vitesses existent, même pour Fr=1, pouvant assurer des zones de refuge pour le poisson. Les forces de trainée ont été mesurées sur le plot. Les évolutions des coefficients de trainée avec le nombre de Froude et des rapports de forme de l'écoulement autour du plot ont ainsi été évaluées. La partie numérique est réalisée avec OpenFOAM pour 4 cas d'étude (Q=10 et 20 l/s, S=0 et 2%) et 2 modèles de turbulence URANS, le RNG k-epsilon et le k-omega SST. Des modélisations en 2D ont également été faites avec Telemac 2D. Les résultats obtenus ont été comparés aux résultats expérimentaux. La modélisation 2D (shallow water) est exploitable seulement pour des nombres de Froude faibles, d'où la nécessité des modélisations en 3D. Le modèle komega SST semble le mieux adapté pour reproduire les écoulements étudiés. Les vitesses locales et les structures en 3D, non quantifiables expérimentalement, ont ensuite été décrites. Les influences du fond et de la surface libre sur le sillage apparaissent clairement en provoquant des vitesses verticales et des tourbillons à grandes échelles. Enfin, une simulation en LES a été conduite. Les structures tourbillonnaires sont mieux représentées que pour les modèles URANS, mais les temps de calcul sont grands.

No description available.

Bubbly flows can be found in many applications in chemical, biological and power engineering. Reliable simulation tools of such flows that allow the design of new processes and optimization of existing one are therefore highly desirable. CFD-simulations applying the multi-fluid approach are very promising to provide such a design tool for complete facilities. In the multi-fluid approach, however, closure models have to be formulated to model the interaction between the continuous and dispersed phase. Due to the complex nature of bubbly flows, different phenomena have to be taken into account and for every phenomenon different closure models exist. Therefore, reliable predictions of unknown bubbly flows are not yet possible with the multi-fluid approach. A strategy to overcome this problem is to define a baseline model in which the closure models including the model constants are fixed so that the limitations of the modeling can be evaluated by validating it on different experiments. Afterwards, the shortcomings are identified so that the baseline model can be stepwise improved without losing the validity for the already validated cases. This development of a baseline model is done in the present work by validating the baseline model developed at the Helmholtz-Zentrum Dresden-Rossendorf mainly basing on experimental data for bubbly pipe flows to bubble columns, bubble plumes and airlift reactors that are relevant in chemical and biological engineering applications. In the present work, a large variety of such setups is used for validation. The buoyancy driven bubbly flows showed thereby a transient behavior on the scale of the facility. Since such large scales are characterized by the geometry of the facility, turbulence models cannot describe them. Therefore, the transient simulation of bubbly flows with two equation models based on the unsteady Reynolds-averaged Navier–Stokes equations is investigated. In combination with the before mentioned baseline model these transient simulations can reproduce many experimental setups without fitting any model. Nevertheless, shortcomings are identified that need to be further investigated to improve the baseline model. For a validation of models, experiments that describe as far as possible all relevant phenomena of bubbly flows are needed. Since such data are rare in the literature, CFD-grade experiments in an airlift reactor were conducted in the present work. Concepts to measure the bubble size distribution and liquid velocities are developed for this purpose. In particular, the liquid velocity measurements are difficult; a sampling bias that was not yet described in the literature is identified. To overcome this error, a hold processor is developed. The closure models are usually formulated based on single bubble experiments in simplified conditions. In particular, the lift force was not yet measured in low Morton number systems under turbulent conditions. A new experimental method is developed in the present work to determine the lift force coefficient in such flow conditions without the aid of moving parts so that the lift force can be measured in any chemical system easily.

Les barrages sur les rivières sont des obstacles à la migration piscicole. Les passes à poissons sont des ouvrages permettant aux espèces piscicoles de migrer, autorisant le rétablissement de la continuité écologique des cours d'eau. Le but de ce travail est de mieux comprendre les phénomènes physiques présents dans les passes à poissons naturelles. Ces passes sont des canaux à forte pente, équipé de rangées de plots en quinconce. Pour valider la pertinence de l'utilisation d'un modèle numérique, l'étude s'est limitée à l'écoulement autour d'un cylindre émergent placé au centre d'un canal. Le travail est décomposé en deux parties, une expérimentale et une numérique. La partie expérimentale est conduite dans un canal transparent de 4m de long, 0,4m de large et 0,4m de hauteur. Le diamètre du cylindre est 4cm et sa hauteur 20cm (toujours émergent). Les cas étudiés sont des débits de 5, 10, 15 et 20 l/s pour une pente nulle. Les nombres de Froude sont supérieurs à 0,5 et les nombres de Reynolds, basés sur le diamètre, sont compris entre 15000 et 50000. Les écoulements ont été filmés et un algorithme de suivi de particules (PTV) a été développé. Des zones de faibles vitesses existent, même pour Fr=1, pouvant assurer des zones de refuge pour le poisson. Les forces de trainée ont été mesurées sur le plot. Les évolutions des coefficients de trainée avec le nombre de Froude et des rapports de forme de l'écoulement autour du plot ont ainsi été évaluées. La partie numérique est réalisée avec OpenFOAM pour 4 cas d'étude (Q=10 et 20 l/s, S=0 et 2%) et 2 modèles de turbulence URANS, le RNG k-epsilon et le k-omega SST. Des modélisations en 2D ont également été faites avec Telemac 2D. Les résultats obtenus ont été comparés aux résultats expérimentaux. La modélisation 2D (shallow water) est exploitable seulement pour des nombres de Froude faibles, d'où la nécessité des modélisations en 3D. Le modèle komega SST semble le mieux adapté pour reproduire les écoulements étudiés. Les vitesses locales et les structures en 3D, non quantifiables expérimentalement, ont ensuite été décrites. Les influences du fond et de la surface libre sur le sillage apparaissent clairement en provoquant des vitesses verticales et des tourbillons à grandes échelles. Enfin, une simulation en LES a été conduite. Les structures tourbillonnaires sont mieux représentées que pour les modèles URANS, mais les temps de calcul sont grands. / The dams on rivers are fishes migration obstacles. The fishways are devices allowing the fishes to migrate, permitting the restauration of the ecological continuity. The aim of this work is to better comprehend the physical phenomena existing in the nature-like fishways. This kind of fishway is a high slope channel with staggered rows of blocks. To validate the relevance of the use of a numerical model, the study is limited to the flow around a single free surface piercing cylinder placed in the center of a flume. The work is in two parts, experimental and numérical. The experimental part is conducted in a transparent flume of 4m length, 0.4m width and 0.4m height. The cylinder diameter is 4cm and its height 20cm (always emerged). The studied cases are flow rates of 5 to 20 l/s for a flat bed. The Froude numbers are over 0.5 et the Reynolds numbers, based on the diameter, are in between 15000 and 50000. The flows were filmed and a particules tracking velocimetry (PTV) algorithm was developped. Slow velocities areas exist, even for Fr=1, allowing shelter zones for a fish. The drag forces were also measured. The drag coefficients evolutions with the Froude number and with the flow aspect ratio were estimated. The numerical part is done with OpenFOAM for 4 cases (Q=10 et 20 l/s, S=0 et 2%) and 2 URANS turbulence models, RNG k-epsilon and k-omega SST. 2D simulations are also carried out with Telemac2D. The results are compared with the experimental ones. The 2D modelisation (shallow water) is workable only for small Froude numbers, which justifies the 3D modelisation. The k-omega SST seems the most relevant to reproduce the studied flows. The local velocities and 3D structures, unquantifiable experimentally, were described. The bed and free surface influences on the wake are clearly shown leading to vertical velocities and big scale vorticies. Finally, a LES simulation was conducted. The vortex structures are better reproducted than the URANS simulations, but the computation times are significant.

Bubbly flows can be found in many applications in chemical, biological and power engineering. Reliable simulation tools of such flows that allow the design of new processes and optimization of existing one are therefore highly desirable. CFD-simulations applying the multi-fluid approach are very promising to provide such a design tool for complete facilities. In the multi-fluid approach, however, closure models have to be formulated to model the interaction between the continuous and dispersed phase. Due to the complex nature of bubbly flows, different phenomena have to be taken into account and for every phenomenon different closure models exist. Therefore, reliable predictions of unknown bubbly flows are not yet possible with the multi-fluid approach. A strategy to overcome this problem is to define a baseline model in which the closure models including the model constants are fixed so that the limitations of the modeling can be evaluated by validating it on different experiments. Afterwards, the shortcomings are identified so that the baseline model can be stepwise improved without losing the validity for the already validated cases. This development of a baseline model is done in the present work by validating the baseline model developed at the Helmholtz-Zentrum Dresden-Rossendorf mainly basing on experimental data for bubbly pipe flows to bubble columns, bubble plumes and airlift reactors that are relevant in chemical and biological engineering applications. In the present work, a large variety of such setups is used for validation. The buoyancy driven bubbly flows showed thereby a transient behavior on the scale of the facility. Since such large scales are characterized by the geometry of the facility, turbulence models cannot describe them. Therefore, the transient simulation of bubbly flows with two equation models based on the unsteady Reynolds-averaged Navier–Stokes equations is investigated. In combination with the before mentioned baseline model these transient simulations can reproduce many experimental setups without fitting any model. Nevertheless, shortcomings are identified that need to be further investigated to improve the baseline model. For a validation of models, experiments that describe as far as possible all relevant phenomena of bubbly flows are needed. Since such data are rare in the literature, CFD-grade experiments in an airlift reactor were conducted in the present work. Concepts to measure the bubble size distribution and liquid velocities are developed for this purpose. In particular, the liquid velocity measurements are difficult; a sampling bias that was not yet described in the literature is identified. To overcome this error, a hold processor is developed. The closure models are usually formulated based on single bubble experiments in simplified conditions. In particular, the lift force was not yet measured in low Morton number systems under turbulent conditions. A new experimental method is developed in the present work to determine the lift force coefficient in such flow conditions without the aid of moving parts so that the lift force can be measured in any chemical system easily.