Turbocharger performance maps are vital components used in an engine-turbocharger matching process, a 1D engine performance development stage and a day-to-day operation of a turbocharged vehicle. The main aim of this thesis is the investigation of the turbocharger compressor performance when operating with an alternative to air substitute gas. This occurs, for instance, when turbocharging and low pressure exhaust gas recirculation (LP EGR) technologies are combined. To conduct the experimental study of the turbocharger performance with substitute gas a steady-state turbocharger test facility with a compressor closed-loop mode has been designed and built within this thesis by the author. Also, for the most accurate performance map determination an uncertainty analysis of a selected turbocharger performance map and an extensive study on surge have also been carried out. The sensor based uncertainty analysis has been a key aspect to help to understand the links between the accuracy of measured quantities and the overall uncertainty of the performance parameters. Such knowledge allowed for a selection of sensors targeting the most accurate data measurement. While investigating the uncertainty of the turbocharger performance maps heat transfer related efficiency uncertainty was also studied. Namely, a series of a semi-adiabatic tests were performed in the low turbocharger speed region which highlighted the issues related to a work and heat transfer separation and uncertainty of the extrapolated performance data. Also, a contribution to the turbocharger heat transfer modelling has been made by supporting the in-house lumped capacitance thermal node model with the 3D CHT (conjugate heat transfer) simulations [1, 2]. Finally, a study of a literature based compressor heat estimation method was performed as an alternative way of separating work and heat transfer (with low speed adiabatic mapping). The experimental surge study was conducted in phases and included the analysis and comparison of the low and high frequency pressure data gathered at various locations downstream and upstream from the compressor and temperature data collected at close distance from impeller eye. It has been concluded that the post-compressor located pressure measurement is preferable (than the pre-compressor pressure measurement) as the FFT (Fast Fourier Transform) magnitude of the peak frequency associated with surge is independent on the distance of the sensor from the compressor. The useage of the temperature sensor installed at the closest distance from the compressor entry allowed an observation of the near surge temperature rise (a result of the air recirculation). However, due to the inconsistent rate of the temperature rise across the various speed lines along with the poor response it offers no benefit from the surge avoidance point of view. The comparison of the available surge metrics revealed that the resultant surge lines were drawn at different operating points especially at the higher turbocharger speed lines where the surge development investigated by the rise of the low frequency FFT magnitude peaks was much more visible. The experimental tests performed in steady-state and pulsating flow conditions have indicated larger surge margin availability for the latter case [3]. Development of a turbocharger rig and gaining the confidence in turbocharger performance map generation allowed the author to carry out the investigation over compressor performance with a substitute gas. The study covered two cases of homogeneous and non-homogeneous gas introduction representing a well and a poorly mixed gases respectively. The substitute gas included various mixtures of CO2 and air and pure CO2. It has been highlighted that when comparing turbomachinery performance maps working with substitute gas non-dimensional speed and mass flow parameters shall be introduced. These parameters allow for the map corrections with respect to individual gas constant (R) and ratio of specific heats (γ). The experimentally obtained compressor performance maps with low CO2 concentration in CO2-air mixtures (3%, 5% and 10%) were successfully corrected with the use of non-dimensional speed and mass flow parameters. However, the compressor performance map obtained for the pure CO2 has revealed significant offsets in pressure ratio, efficiency, surge and choke flow locations. This is due to a significantly different γ. In the attempt of the further performance correction a method proposed by Roberts and Sjolander has been followed. As a result of such, a poor match between the measured and predicted values of compressor efficiency was achieved (n exponent = 0.8). A closer correlation was obtained if the n exponent was made a speed dependent variable. This observation has suggested that the measurement of compressor efficiency was affected by the heat transfer between the uninsulated turbomachinery components. Due to the time limitations this assertion has not been investigated experimentally. Realising this limitation, therefore, a series of adiabatic CFD simulations have been performed instead. These simulations have shown that for the case of pure CO2 a reasonable match between the simulated and predicted values of efficiency and pressure ratio was achieved. The experimental and numerical comparison of the compressor performance for homogeneously and non-homogeneously introduced substitute gas did not show any significant compressor performance changes. Finally, experimental study of selected configurations of the intake pipework and EGR mixing valve has shown that complex flow regimes can be developed within the LP EGR system affecting the compressor’s surge margin, efficiency and width of the map. This demonstrates that the aerodynamic disturbances of an EGR mixing valve may have the largest influence on the compressor map compared to all other factors.

Let 𝑋 be a compact subset of the complex plane and denote by 𝑅𝑝(𝑋) the closure of rational functions with poles off 𝑋 in the 𝐿𝑝(𝑋) norm. We show that if a point 𝑥0 admits a bounded point derivation on 𝑅𝑝(𝑋) for 𝑝 > 2, then there is an approximate derivative at 𝑥0. We also prove a similar result for higher order bounded point derivations. This extends a result of Wang, which was proven for 𝑅(𝑋), the uniform closure of rational functions with poles off 𝑋. In addition, we show that if a point 𝑥0 admits a bounded point derivation on 𝑅(𝑋) and if 𝑋 contains an interior cone, then the bounded point derivation can be represented by the difference quotient if the limit is taken over a non-tangential ray to 𝑥0. We also extend this result to the case of higher order bounded point derivations. These results were first shown by O'Farrell; however, we prove them constructively by explicitly using the Cauchy integral formula.

Au cours des dernières années, la branche de la statistique consacrée à l'étude de variables fonctionnelles a connu un réel essor tant en terme de développements théoriques que de diversification des domaines d'application. Nous nous intéressons plus particulièrement dans ce mémoire à des modèles de régression dans lesquels la variable réponse est réelle tandis que la variable explicative est fonctionnelle, c'est à dire à valeurs dans un espace de dimension infinie. Les résultats que nous énonçons sont liés aux propriétés asymptotiques de l'estimateur à noyau généralisé au cas d'une variable explicative fonctionnelle. Nous supposons pour commencer que l'échantillon que nous étudions est constitué de variables α-mélangeantes et que le modèle de régression est de nature nonparamétrique. Nous établissons la normalité asymptotique de notre estimateur et donnons l'expression explicite des termes asymptotiquement dominants du biais et de la variance. Une conséquence directe de ce résultat est la construction d'intervalles de confiance asymptotiques ponctuels dont nous étudions les propriétés aux travers de simulations et que nous appliquons sur des données liées à l'étude du courant marin El Niño. On établit également à partir du résultat de normalité asymptotique et d'un résultat d'uniforme intégrabilité l'expression explicite des termes asymptotiquement dominants des moments centrés et des erreurs Lp de notre estimateur. Nous considérons ensuite le problème des tests de structure en régression sur variable fonctionnelle et supposons maintenant que l'échantillon est composé de variables indépendantes. Nous construisons une statistique de test basée sur la comparaison de l'estimateur à noyau et d'un estimateur plus particulier dépendant de l'hypothèse nulle à tester. Nous obtenons la normalité asymptotique de notre statistique de test sous l'hypothèse nulle ainsi que sa divergence sous l'alternative. Les conditions générales sous lesquelles notre résultat est établi permettent l'utilisation de notre statistique pour construire des tests de structure innovants permettant de tester si l'opérateur de régression est de forme linéaire, à indice simple, . . . Différentes procédures de rééchantillonnage sont proposées et comparées au travers de diverses simulations. Nos méthodes sont enfin appliquées dans le cadre de tests de non effet à deux jeux de données spectrométriques.

Nous étudions les espaces de formes harmoniques $L^2$ essentiellement sur les variétés de volume fini, à courbure négative et pincée. Notre but est d'en trouver une interprétation topologique. Nous montrons, dans un premier temps, que si la courbure est suffisamment pincée, il y a une telle interprétation simple de ces espaces. Nous construisons également des exemples qui montrent que notre hypothèse de pincement de la courbure est nécessaire et optimale. Dans un deuxième temps, nous considérons des variétés qui sont de plus kaehlériennes, et nous montrons, sans hypothèse sur le pincement, qu'on peut donner une interprétation topologique de l'espace des k-formes harmoniques $L^2$, pour certains entiers k. Enfin, nous étudions plus généralement la $L^p$-cohomologie de nos variétés.

<p>Haptoglobin (Hp) is a serum protein known for its ability to form a tight complex with hemoglobin (Hb) and thereby inhibiting the oxidative activity of Hb. </p><p>Mammalian Hp is synthesized as a precursor (proHp) that undergoes proteolytic cleavage by a previously unidentified enzyme in the endoplasmic reticulum (ER). In this study, a proHp-cleaving enzyme was isolated from human serum and identified as complement C1r-like protein (C1rLP). Co-expression of C1rLP with proHp in mammalian cells resulted in cleavage of the latter protein in the ER. Mutation of either the active site serine residue in C1rLP or the arginine residue in the cleavage site of Hp abolished the cleavage of proHp by C1rLP. RNAi studies in mammalian cells identified the proHp-cleaving enzyme as C1rLP.</p><p>Hp has been found in all mammals studied to date but its presence in non-mammalian species has not been unambiguously shown. By searching currently available genomic DNA and cDNA sequence databases, a gene orthologous to mammalian <i>Hp</i> was found in bony fish. Hp-like protein expressed from this gene was demonstrated to be a major Hb protein in fish serum. Surprisingly, no Hp-like gene was found in the genomes of either frog or chicken. In chicken, a protein previously described as Hp was identified as PIT54, a member of a scavenger receptor cysteine-rich family of proteins. Interestingly, ostrich serum seemed to contain two Hb-binding proteins; one similar to PIT54 and one to mammalian Hp. We are not aware of any other case where the function of one gene has been taken over by another, completely unrelated gene</p><p>Fish Hp (fHp) is composed of a serine proteinase-related domain preceded by an extension consisting of several aminoa acids and a signal peptide. The extension contains a consensus motif for cleavage by subtilisin-like proprotein convertases (SPCs). fHp was found to be cleaved by SPCs in the Golgi complex.</p><p>Collectively, this thesis presents evidence that Hp has undergone significant changes during evolution with respect to its molecular organization and to the mechanism of its proteolytic cleavage.</p>

The class of POP (Polynomial Optimization Problems) covers a wide rang of optimization problems such as 0 - 1 integer linear and quadratic programs, nonconvex quadratic programs and bilinear matrix inequalities. In this paper, we review some methods on solving the unconstraint case: minimize a real-valued polynomial p(x) : Rn → R, as well the constraint case: minimize p(x) on a semialgebraic set K, i.e., a set defined by polynomial equalities and inequalities. We also summarize some questions that we are currently considering. / Singapore-MIT Alliance (SMA)

Haptoglobin (Hp) is a serum protein known for its ability to form a tight complex with hemoglobin (Hb) and thereby inhibiting the oxidative activity of Hb. Mammalian Hp is synthesized as a precursor (proHp) that undergoes proteolytic cleavage by a previously unidentified enzyme in the endoplasmic reticulum (ER). In this study, a proHp-cleaving enzyme was isolated from human serum and identified as complement C1r-like protein (C1rLP). Co-expression of C1rLP with proHp in mammalian cells resulted in cleavage of the latter protein in the ER. Mutation of either the active site serine residue in C1rLP or the arginine residue in the cleavage site of Hp abolished the cleavage of proHp by C1rLP. RNAi studies in mammalian cells identified the proHp-cleaving enzyme as C1rLP. Hp has been found in all mammals studied to date but its presence in non-mammalian species has not been unambiguously shown. By searching currently available genomic DNA and cDNA sequence databases, a gene orthologous to mammalian Hp was found in bony fish. Hp-like protein expressed from this gene was demonstrated to be a major Hb protein in fish serum. Surprisingly, no Hp-like gene was found in the genomes of either frog or chicken. In chicken, a protein previously described as Hp was identified as PIT54, a member of a scavenger receptor cysteine-rich family of proteins. Interestingly, ostrich serum seemed to contain two Hb-binding proteins; one similar to PIT54 and one to mammalian Hp. We are not aware of any other case where the function of one gene has been taken over by another, completely unrelated gene Fish Hp (fHp) is composed of a serine proteinase-related domain preceded by an extension consisting of several aminoa acids and a signal peptide. The extension contains a consensus motif for cleavage by subtilisin-like proprotein convertases (SPCs). fHp was found to be cleaved by SPCs in the Golgi complex. Collectively, this thesis presents evidence that Hp has undergone significant changes during evolution with respect to its molecular organization and to the mechanism of its proteolytic cleavage.

No description available.

We give a systematic study of the Hardy spaces of functions with values in the non-commutative Lp-spaces associated with a semifinite von Neumann algebra M. This is motivated by matrix valued harmonic analysis (operator weighted norm inequalities, operator Hilbert transform), as well as by the recent development of non-commutative martingale inequalities. Our non-commutative Hardy spaces are defined by non-commutative Lusin integral functions. It is proved in this dissertation that they are equivalent to those defined by the non-commutative Littlewood-Paley G-functions. We also study the Lp boundedness of operator valued dyadic paraproducts and prove that their Lq boundedness implies their Lp boundedness for all 1 < q < p < ∞.

Thèse doctorat : Mathématiques : Strasbourg 1 : 2005. / Titre provenant de l'écran-titre. Bibliogr. 3 p.