The molecular magnet [FeII(£G)FeII(£N)(ox)2(Phen)2]n, whose chemical formula is C28H16Fe2N4O8 for unity, has been studied by magnetization measurements, neutron diffraction, and field-dependent specific heat. From the magnetization measurements, the quasi-ferrimagnetic behavior at T>Tm region can be well described with alternating Land&#x00E9; factors within 1D Ising chain model. However, in T<Tm region, the construction of long-range magnetic ordering due to the increase of interchain interaction was investigated, which is consistent with the anomaly shown in the low temperature specific heat measurement. Furthermore, an intrinsic antiferromagnetic configuration is deduced from analyzing Bragg pattern of neutron scattering. In specific heat measurement, a £f-type anomaly indicating the long-range magnetic ordering was observed. In addition, the magnetic entropy due to this anomaly is much smaller than expected value indicating the spin fluctuated as short-range ordering at T>Tm.

<p>1D engine simulations of turbocharged engines are difficult to <!-- @page { size: 21cm 29.7cm; margin: 2cm } P { margin-bottom: 0.21cm } --></p><p>Techniques that can increase the SI- engine efficiency while keeping the emissions very low is to reduce the engine displacement volume combined with a charging system. Advanced systems are needed for an effective boosting of the engine and today 1D engine simulation tools are often used for their optimization.</p><p>This thesis concerns 1D engine simulation of a turbocharged SI engine and the introduction of CFD computations on components as a way to assess inaccuracies in the 1D model.</p><p>1D engine simulations have been performed on a turbocharged SI engine and the results have been validated by on-engine measurements in test cell. The operating points considered have been in the engine’s low speed and load region, with the turbocharger’s waste-gate closed.</p><p>The instantaneous on-engine turbine efficiency was calculated for two different turbochargers based on high frequency measurements in test cell. Unfortunately the instantaneous mass flow rates and temperatures directly upstream and downstream of the turbine could not be measured and simulated values from the calibrated engine model were used. The on-engine turbine efficiency was compared with the efficiency computed by the 1D code using steady flow data to describe the turbine performance.</p><p>The results show that the on-engine turbine efficiency shows a hysteretic effect over the exhaust pulse so that the discrepancy between measured and quasi-steady values increases for decreasing mass flow rate after a pulse peak.</p><p>Flow modeling in pipe geometries that can be representative to those of an exhaust manifold, single bent pipes and double bent pipes and also the outer runners of an exhaust manifold, have been computed in both 1D and 3D under steady and pulsating flow conditions. The results have been compared in terms of pressure losses.</p><p>The results show that calculated pressure gradient for a straight pipe under steady flow is similar using either 1D or 3D computations. The calculated pressure drop over a bend is clearly higher1D engine simulations of turbocharged engines are difficult to <!-- @page { size: 21cm 29.7cm; margin: 2cm } P { margin-bottom: 0.21cm } -->using 1D computations compared to 3D computations, both for steady and pulsating flow. Also, the slow decay of the secondary flow structure that develops over a bend, gives a higher pressure gradient in the 3D calculations compared to the 1D calculation in the straight pipe parts downstream of a bend.</p><p> </p>

<p>In the future, new challenges will occur during the product development in the vehicular industry when emission legislations getting tighter. This will also affect the truck cooling system and therefore increase needs for analysing the system at different levels of the product development. Volvo 3P wishes for these reasons to examine the possibility to use AMESim as a future 1D analysis tool. This tool can be used as a complement to existing analysis methods at Volvo 3P. It should be possible to simulate pressure, flow and heat transfer both steady state and transient.</p><p>In this thesis work a cooling system of a FH31 MD13 520hp truck with an engine driven coolant pump is studied. Further a model of the cooling system is built in AMESim together with necessary auxiliary system such as oil circuits. The model is validated using experimental data that have been produced by Volvo 3P at the Gothenburg facility.</p><p>The results from validation and other simulations show that the model gives a good picture of the cooling system. It also gives information about pressure, flow and heat transfer in steady state conditions. Further a design modification is done, showing how a change affects the flow in the cooling system.</p><p>The conclusion is that a truck cooling system can be built and simulated in AMESim. Further, it shows that AMESim meets the requirements Volvo 3P in Gothenburg has set up for the future 1D analysis tool and thereby AMESim is a good complement to the already existing analysis method.</p>

The development of a site-specific seismic hazard curve for a soil site requires the incorporation of site effects into the hazard calculation through the use of a site-specific amplification function. This study investigates the effect on the resulting soil hazard curves of different approaches to compute the site-specific amplification function. Amplification functions and their standard deviations can be developed using equivalent linear site response analyses. This study investigates the amplification function predictions of one-dimensional (1D) and two-dimensional (2D) site response analyses. For 1D analysis, one set of analyses are performed using time series (TS) input motions while a second set is performed using random vibration theory (RVT). One-dimensional site response analyses are performed for a shallow and a deep soil site and the results are compared for seismic hazard predictions. The influence of spatial variability introduced through randomization of site shear wave velocity (V[subscript S]) is also investigated. Shear wave velocity profile randomization does not significantly change the predicted amplification functions, except for the RVT analysis near the site period. At these periods, (V[subscript S]) randomization reduces the amplification function predicted by RVT making it more similar to the TS analysis prediction. The surface hazard at a site is dependent on the median amplification factor and its associated standard deviation. Spatial variability and uncertainties in soil properties across a site are often taken into account by modeling multiple 1D profiles in 1D site response analyses. However, this approach assumes that analyzing multiple 1D profiles captures accurately the effects of the true multi-dimensional spatial variability of the soil properties. This study investigates the results of two-dimensional (2D) site response analyses that incorporate spatial variability in the (V[subscript S]) profile through Monte Carlo simulation. Two-dimensional site response analyses are performed for 2D random fields generated with various statistical parameters (i.e. vertical and horizontal correlation distances) to investigate the effect of different levels of spatial variability on surface response across a region of interest (ROI). Two-dimensional site response analyses are performed for a shallow site. Results indicate that horizontal correlation distance has more influence on the analyses results than the vertical correlation distance. As the horizontal correlation distance increases, the median surface response spectrum across the ROI decreases. This reduction in median surface response is more pronounced around the site period. The influence of the vertical correlation distance is more pronounced when the horizontal correlation distance is large. As the vertical correlation distance increases, the median surface response spectrum across the ROI increases, which is more pronounced around the period of the motion. The predictions of 1D and 2D site response analyses modeling the (V[subscript S]) variability are compared. 1D analyses are performed on separately generated 1D (V[subscript S]) profiles (infinite horizontal correlation) and on the (V[subscript S]) profiles across the ROI of each 2D (V[subscript S]) field realization generated for 2D analysis (finite horizontal correlation). The results indicate that both sets of 1D analyses predict lower median response than 2D analyses. The 1D analyses with finite horizontal correlation display comparable levels of variability in the site response, however 1D analyses with infinite horizontal correlation display higher variability. / text

In the future, new challenges will occur during the product development in the vehicular industry when emission legislations getting tighter. This will also affect the truck cooling system and therefore increase needs for analysing the system at different levels of the product development. Volvo 3P wishes for these reasons to examine the possibility to use AMESim as a future 1D analysis tool. This tool can be used as a complement to existing analysis methods at Volvo 3P. It should be possible to simulate pressure, flow and heat transfer both steady state and transient. In this thesis work a cooling system of a FH31 MD13 520hp truck with an engine driven coolant pump is studied. Further a model of the cooling system is built in AMESim together with necessary auxiliary system such as oil circuits. The model is validated using experimental data that have been produced by Volvo 3P at the Gothenburg facility. The results from validation and other simulations show that the model gives a good picture of the cooling system. It also gives information about pressure, flow and heat transfer in steady state conditions. Further a design modification is done, showing how a change affects the flow in the cooling system. The conclusion is that a truck cooling system can be built and simulated in AMESim. Further, it shows that AMESim meets the requirements Volvo 3P in Gothenburg has set up for the future 1D analysis tool and thereby AMESim is a good complement to the already existing analysis method.

Cette thèse porte sur la modélisation 0D/1D de la combustion Diesel dans les moteurs récents. L'objectif est d'augmenter la précision des modèles tout en limitant les temps de calcul associés afin d'utiliser la simulation comme un outil dédié à la mise au point. Dans une première partie, le développement d'un modèle 0D orienté simulation système est présenté. La prise en compte de l'ensemble des phénomènes physico-chimiques se déroulant dans la chambre de combustion confère au modèle un niveau de prédictivité conséquent. Un nouveau modèle de combustion de prémélange est proposé, permettant une modélisation détaillée des combustions fortement diluées et des combustions relatives aux injections précoces. Une approche innovante permettant de quantifier les interactions entre les jets pour la multi injection est également proposée. Après calibration sur un nombre restreint d'essais moteur, les résultats du modèle global sont comparés à des mesures expérimentales pour toute la plage de fonctionnement du moteur. La seconde partie de ce travail porte sur la modélisation 1D de la combustion Diesel. Un modèle de jet Diesel est d'abord développé et validé sur des mesures expérimentales. Ce modèle est ensuite étendu à des conditions réactionnelles à l'aide d'un couplage avec un modèle de combustion. Ce dernier s'appuie sur une tabulation des mécanismes de cinétique chimique, ainsi que sur une approche Eddy Break-Up permettant de modéliser le taux de réaction lié au micro mélange. Ce modèle est ensuite intégré à un modèle de chambre de combustion et une première validation du modèle sur des essais moteur réels est entreprise.

La présente thèse porte sur la modélisation dédiée au contrôle des phénomènes physiques se produisant au travers des restrictions de la chaîne d'air du moteur. L'objectif est d'assurer la précision des modèles tout en limitant les temps de calcul associés. En effet, les modèles dédiés au contrôle nécessitent un temps de calcul court (proche du temps réel) afin d'être exploitables dans un processus de développement. En parallèle de cela, les normes concernant les rejets polluants sont de plus en plus drastiques, et nécessitent de prendre en compte finement les phénomènes physiques mis en jeu. Dans une première partie, les équations des phénomènes physiques liés aux turbocompresseurs radiaux sont introduites dans une approche cartographique. Les équations fondamentales des turbomachines sont développées et utilisées afin de construire une méthode d'interpolation / extrapolation de champs turbocompresseur expérimentaux incomplets. Dans un second temps, les résultats d'essais réalisés lors de la thèse sont utilisés pour identifier les transferts thermiques au sein des turbocompresseurs. Un modèle dynamique d'échange thermique est ensuite construit. Le modèle final permet d'obtenir une cartographie complète des champs compresseur et turbine, tout en prenant en compte l'impact des transferts thermiques sur les performances des turbomachines. La seconde partie porte sur la modélisation des restrictions (soupapes, changements de section...) rencontrées sur les MCI. Une méthode pour la résolution quasistatique des équations Euler 1D complètes (masse, énergie, moment) est proposée afin de construire les cartographies associées aux restrictions considérées, sans introduire de coefficient de correction expérimental. Ces cartographies sont utilisables en tant que modèles moyens ou utilisées comme conditions limites de codes aérodynamiques 1D. En cas de couplage avec un code 1D, une méthode de correction d'entropie basée sur un algorithme de linéarisation est proposée afin de réduire le temps de convergence aux conditions limites du domaine de calcul.Finalement, les développements sont validés expérimentalement en écoulements stabilisés et transitoires.

国立情報学研究所で電子化したコンテンツを使用している。

La compréhension des processus écologiques affectant la matière transitant ou produite dans les estuaires nécessite une bonne connaissance des facteurs qui contrôlent le développement des différents groupes biologiques et leurs relations trophiques dans le milieu.Les milieux estuariens macrotidaux sont le plus souvent caractérisés par des fortes turbidités qui limitent généralement la production primaire locale. Ils présentent cependant une forte productionsecondaire et des concentrations en chlorophylle non négligeables dans la colonne d’eau. L’une des problématiques demeure donc l’origine de cette production primaire dans les eaux turbides de ces milieux. Cette thèse s’inscrit dans cette logique ; dans la continuité des travaux réalisés précédemment. Elle vise à analyser l’importance et le rôle de la production primaire dans la production globale de l’estuaire de la Gironde. Le présent manuscrit résume ainsi l’ensemble des travaux réalisés et lesrésultats obtenus sur les principaux groupes de producteurs primaires (phytoplancton et microphyto-benthos) présents le long du continuum fluvio-estuarien de la Gironde. Les principales questions qui sont développées dans ce travail structurent ce rapport en trois axes de recherche. Le premier axe permet, au moyen d’une modélisation 1D de transport et réaction, de simuler,dans l’espace et le temps, la dynamique de la chlorophylle-a et des sels nutritifs, témoins d’uneproduction primaire dans le milieu. Les résultats indiquent que la dynamique de la chlorophylle-adans la Gironde reste fortement dépendante des débits et des temps de résidence très courts des massesd’eau, renforçant ainsi une origine allochtone du phytoplancton. Parmi les sources potentielles deproduction d’origine allochtone présents dans la colonne d’eau, les microalgues benthiques jouent unrôle majeur puisqu’elles peuvent être remises en suspension au cours de chaque marée. L’analyse dece compartiment et de sa production a permis dans un second axe de travail, de montrer que les zonesintertidales situées en aval de l’estuaire sont les plus productives et sont majoritairement autotrophes.Elles produiraient relativement plus de matière que les zones situées en amont qui elle, sont fortementinfluencées par les débits des fleuves.Finalement dans le troisième axe, les différentes voies de transfert de la matière organique au seindu réseau trophique, où les copépodes occupent une place prépondérante, sont analysées au moyendu traçage par les isotopes stables de carbone et de l’azote (13C et 15N) / Abstract

Audiomagnetotelluric measurements with (CSAMT) and without (AMT) a controlled source were performed near Gällivare and Kiruna in Swedish Lapland in order to retrieve representative conductivity models of the subsurfaces. Magnetotelluric transfer functions were gained from processed time series’ and subsequently inverted to generate the sought models successfully. Additionally, a strike angle analysis was performed to determine the dimension of the ground structures. That information was used to justify the approaches of 1D and 2D inversions of the data sets and to judge their applicability. In Kiruna, two profiles were installed. One profile is considered to be in line with the strike direction, the other profile was oriented rather orthogonal to the strike direction. In Gällivare, only one profile was installed orthogonally with respect to the strike direction. The strike analysis showed a preferentially 2-dimensional structure for Kiruna’s parallel profile. For the orthogonal oriented profiles from Kiruna and Gällivare, the analysis revealed a 2D (with distortions) to 3D dimension of the ground structures. For the AMT method, it was possible to generate 1-dimensional and 2-dimensional models. Regarding the CSAMT data, it was only possible to generate a 1D conductivitymodel for the subsurface. Due to a significant transmitter overprint, no undistorted start model for the 2-dimensional CSAMT data inversion could be produced. The models from Kiruna had a sufficient data quality and thus resulted in reliable 2D AMT resistivity models with, locally, 2 to 3 layers. However, in combination with the 1D models for AMT and CSAMT, a 3-layer structure was predicted, where a resistive layer is covered by a thin conductive layer and underlaid by a rather conductive basement. For Gällivare’s profile, the data quality was good such that for all inversion methods good results were achieved. The predicted 2-layer models were resolved for for depths between 10m and 10,000m and coincide with the at hand geological maps and cross sections.