Polymer spiral film gas-liquid heat exchanger for waste heat recovery in exhaust gases

In this master thesis report the development of an innovative spiral heat exchanger based on polymer materials is described. Building prototypes, erection of a test bench and firsts tests of the heat exchanger are presented. The heat exchanger prototype survived all tests especially several days in contact with aggressive gases. A facility integrating a Diesel exhaust gases production has been developed to test this heat exchanger design. Performance results obtained during the tests are analysed. Measurement acquisition software developed with Labview was also used. Challenges have been overcome to run the facility in stable conditions in order to obtain reliable measurement. Heat load recovery achieved with the presented heat exchanger is in the range of 1.5 kW thermic but potential heat recovery about 3.5kW might be achievable. Overall heat transfer coefficient is improved compared to other polymer based heat exchanger design. Pressure drop on gas channel is in the range of several mbar and must be further improved and fouling must be minimized. Such a design based on polymer film technology provides better corrosion and chemical resistance compared to conventional metal heat exchangers. Due to the smooth surface of polymer film fouling is reduced. Series production and usage of such heat exchangers would allow operating low temperature waste heat recovery in gases at affordable costs. One promising application is heat recovery in soiled gases in combination with ORC power generation

Assessment of Left Ventricular Function in Cardiac MSCT Imaging by a 4D Hierarchical Surface-Volume Matching Process

Multislice computed tomography (MSCT) scanners offer new perspectives for cardiac kinetics evaluation with 4D dynamic sequences of high contrast and spatiotemporal resolutions. A new method is proposed for cardiac motion extraction in multislice CT. Based on a 4D hierarchical surface-volume matching process, it provides the detection of the heart left cavities along the acquired sequence and the estimation of their 3D surface velocity fields. A Markov random field model is defined to find, according to topological descriptors, the best correspondences between a 3D mesh describing the left endocardium at one time and the 3D acquired volume at the following time. The global optimization of the correspondences is realized with a multiresolution process. Results obtained on simulated and real data show the capabilities to extract clinically relevant global and local motion parameters and highlight new perspectives in cardiac computed tomography imaging

Modélisation Markovienne pour l'estimation combinée de forme et de mouvement : Application au coeur en imagerie scanner multibarrette

Une méthode d'estimation conjointe de forme et de mouvement non rigide à partir de séquences temporelles tri-dimensionnelles est proposée. Basée sur une mise en correspondance surface-volume, elle permet, à partir d'une unique forme segmentée, d'estimer la forme et son mouvement sur toute la séquence. Une modélisation Markovienne combinée à un algorithme de recuit simulé estime les correspondances entre les noeuds du maillage modélisant l'objet à l'instant t et les voxels du volume à l'instant t + 1. La méthode a été appliquée à l'extraction de formes et de mouvements cardiaques en tomodensitométrie multibarrette. Les tests, réalisés sur données simulées et données réelles, ont donné des résultats prometteurs

Joint Shape and Motion Estimation using Markovian Fields : Application to Multislice Computed Tomography Cardiac Imaging

We propose a method for joint surface and non-rigid motion estimation from three-dimensional dynamic sequences. Based on a surface-volume matching, it provides, from one first segmented surface, both motion and deformations of the object of interest along the whole sequence. A Markovian model, combined with a simulated annealing process, estimates the correspondences between the nodes of the surface mesh modeling the object of interest at one time and the voxels of the volume representing the object at the following time. The method has been applied to cardiac surface and motion extraction in Multislice Computed Tomography. Tests realized with simulated motion and on real data have provided promising results.Une méthode d'estimation conjointe de forme et de mouvement non rigide à partir de séquences temporelles tridimensionnelles est proposée. Reposant sur une mise en correspondance surface-volume, elle permet, à partir d'une première segmentation de l'objet d'intérêt, d'estimer le mouvement de l'objet et ses déformations sur toute la séquence temporelle d'observation. Une modélisation markovienne combinée à un algorithme de recuit simulé estime les correspondances entre les noeuds du maillage de surface modélisant l'objet à un instant et les voxels du volume représentant l'objet à l'instant suivant. La méthode a été appliquée à l'extraction de formes et de mouvements cardiaques en tomodensitométrie multibarrette. Les tests, réalisés à la fois avec des mouvements simulés et sur des données réelles, ont donné des résultats prometteurs

: Gender differences in STEMI

International audienceBACKGROUND: Gender differences in presentation, management and outcome in patients with ST-segment elevation myocardial infarction (STEMI) have been reported. AIM: To determine whether female gender is associated with higher inhospital mortality. METHODS: Data from ORBI, a regional STEMI registry of 5 years' standing, were analysed. The main data on presentation, management, inhospital outcome and prescription at discharge were compared between genders. Various adjusted hazard ratios were then calculated for inhospital mortality (women versus men). RESULTS: The analysis included 5000 patients (mean age 62.6±13 years), with 1174 women (23.5%). Women were on average 8 years older than men, with more frequent co-morbidities. Median ischaemia time was 215 minutes (26 minutes longer in women; P<0.05). Reperfusion strategies in women less frequently involved fibrinolysis, coronary angiography, radial access and thrombo-aspiration. Female gender, especially in patients aged<60 years, was associated with poorer inhospital prognosis (including higher inhospital mortality: 9% vs. 4% in men; P<0.0001), and underutilization of recommended treatments at discharge. Moreover, excess female inhospital mortality was independent of presentation, revascularization time and reperfusion strategy (hazard ratio for women 1.33, 95% confidence interval 1.01-1.76; P=0.04). CONCLUSIONS: One in four patients admitted for STEMI was female, with significant differences in presentation. Female gender was associated with less-optimal treatment, both in the acute-phase and at discharge. Efforts should be made to reduce these differences, especially as female gender was independently associated with an elevated risk of inhospital mortality