Permeability, strength and electrochemical studies on ceramic multilayers for solid-state electrochemical cells

An electrochemical reactor can be used to purify flue gasses. Such a reactor can be a multilayer structure consisting of alternating layers of porous electrodes and electrolytes (a porous cell stack). In this work optimization of such a unit has been done by changing the pore former composition and the electrode powder pre-treatment. The effect on permeability, mechanical strength and electrochemical behavior was studied in this work. The effects were evaluated by measuring the pressure difference over the samples in relation to the flow through the sample, by the ball on ring method and by electrochemical impedance spectroscopy in air at temperatures between 300 and 450 °C. The resulting structures were also evaluated with scanning electron microscopy.The work showed a dependence on the pore former composition and electrode powder pre-treatment resulting in variations in porosity, strength and flow resistance. A higher porosity gives a lower backpressure. The electrochemical performance shows that both thickness and amount of pore former in the electrolyte is important, but almost no dependence of electrode composition on the polarization resistances within the tested compositions

Power Tag-Axle Traction Assembly (P\u27TATA)

Project P’TATA encompassed the design of a selectively-powered tag axle for 6X2-configured Class-8 on-highway tractors, to aid the vehicle in regaining traction during reduced-friction events. For increased fuel savings, 6X2 (1 driving axle, two unpowered axles) configured tractors are preferred over their 6X4 (two driving axles) counterparts; however, the loss of a powered axle renders 6X2 axles more susceptible to slipping events, where the amount of torque required to maintain non-slipping contact with the road exceeds the abilities of the single drive axle. For this and other reasons, the 6X4-configured tractors are chosen despite the fuel efficiency benefits of the 6X2 configuration. Therefore, improvement of the 6X2 tractors’ ability to escape from slipping events should improve driver safety and enhance the tractors’ competitive edge in the market. The design process began with determination of the tag axle torque required to drive the truck out of a slipping event, and a comparison of different power transmission methods. After choosing a transmission method, the electronic control and mechanical systems were designed to so that a motor could engage the axle, transmit power, and then disengage. Using existing and custom-modeled parts, a 3-D model of the system was assembled in CAD software, and a scaled down prototype was constructed to test the control system. An electro-mechanical add-on system was designed to meet the criteria presented by Daimler Trucks of North America. This assembly, shown in Figure 1, employs one DC motor to power the tag axle. A Bendix drive allows for engagement between the motor and the 40:1 reduction worm gear box that multiplies the motor torque. Electricity is pulled from the tractor’s standard battery bank. The electronic control system monitors the wheel speeds at the tag and driving axles, and identifies slipping conditions based on a minimum difference between those speeds. Flowchart and block diagrams of the electronic control circuit were drawn up; parts were ordered and the prototype was built based on these drawings. Once the prototype control circuit was functioning properly, a circuit board was prepared and readied to accept the components of the control circuit. The circuit board was then tested, first for proper wiring and then to ensure proper operation. The final design provides 1120 ft-lbs of torque to the tag axle, remains lightweight at 99.5 lbs compared to the 380 lb differential used in a 6x4, and remains cost-effective with an estimated materials price of $798.42 out of the allotted$1500 (rough estimate not including manual labor). It is capable of driving the truck at 15 mph out of slip on a 4% gradient of sleek ice. The add-on also does not require significant alterations to the existing tag axle design. The design meets the given criteria, but the industry advisor advanced some further design optimization requests that should be considered in future design iterations. The team recommends the implementation of a higher voltage 3-phase electric motor because they provide more horsepower and would require a lower gear reduction for the system. The Bendix-driven engagement mechanism may need to be redesigned to ensure reliable operation. Ultimately, the success of the system must be validated, both by computer stress simulations and by physical testing with full-scale prototypes, prior to large scale manufacturing and implementation

Study of the mechanical behavior of an intermetallic hydride compound used in hydrogen storage

La raréfaction des combustibles fossiles et la prise en compte de plus en plus importante des enjeux environnementaux incite à rechercher de nouvelles pistes de production, stockage et transport de l’énergie. Le développement de la filière hydrogène dépend des améliorations de chacun de ces principaux maillons qui sont la production, le stockage, la distribution et l’utilisation de l’hydrogène.Cette thèse se consacre au stockage de l’hydrogène par absorption dans des matériaux solides pulvérulents composés d’hydrures intermétalliques. Les performances de ce type de stockage dépendent grandement de la gestion des échanges de chaleurs imposés par le caractère exothermique de la réaction d’hydruration (absorption d’hydrogène par le matériau) et respectivement le caractère endothermique de la réaction de déshydruration (désorption d’hydrogène par le matériau). Cette nécessité a guidé la conception des réservoirs vers une architecture interne cellulaire. Si la thermique des réservoirs est très étudiée, les mécanismes de gonflement-dégonflement cycliques des hydrures lors de l’absorption et la désorption d’hydrogène sont assez peu abordés dans la littérature. Pourtant, les interactions mécaniques de la poudre hydrure sur les parois des cellules peuvent remettre en cause l’intégrité du réservoir. La mécanique des milieux granulaires constitue ainsi un apport essentiel à l’analyse et à termes à la prédiction du comportement mécanique du lit de poudre hydrure au sein du réservoir.Cette thèse présente en premier lieu la caractérisation expérimentale du comportement mécanique d’un hydrure intermétallique Ti-Cr-V à différents états de cyclage sous hydrogène en cellule instrumentée en incluant l’analyse des mécanismes de gonflement-dégonflement. L’analyse du comportement mécanique est abordée par une approche de type mécanique des milieux granulaires basée principalement sur la méthode des éléments discrets (DEM). Ces travaux ont permis d’identifier les caractéristiques et le comportement mécanique de l’hydrure (granulométrie, compression en matrice, écoulement) ainsi que l’évolution de paramètres liés au cyclage. Les effets du mécanisme de réarrangement opérant lors du cyclage à l’échelle des grains d’hydrure ont pu être identifiés expérimentalement. En particulier, la variation de volume cyclique du matériau entraine un tassement progressif du lit de poudre, une diminution de la porosité et une augmentation des niveaux de contraintes. Ce comportement a été reproduit numériquement par des simulations impliquant des particules discrètes de formes sphériques et de formes agrégées complexes.It is harder and harder to find fossil fuels and it becomes therefore more and more expensive. Furthermore the environmental impacts of energy are more and more taken into account. For those reasons new solutions to produce, store, transport energy are currently researched and/or developed. Among those solutions, hydrogen system could be a good solution depending and how its main parts (production, storage, supply and use) are improved.This PhD is relative to hydrogen storage in intermetallic hydride compouds. Hydrogen tanks using these kind of materials have to allow good thermal control of the hydride powder especially because of the exothermicity of the hydriding and endothermicity of the unhydriding reaction. That's why the internal architecture of these vessels are often cellular, the cell walls playing the role of a thermal conductor. If the thermal aspects relative to these tanks are often studied, it is not the case of the mechanical phenomenon induced by the swelling and shrinking of the grains during absorption and desorption of hydrogène by the material. However, the mechanical interaction between the powder and the cell walls could endanger the tank.This PhD consists of two main parts. The first part is a mechanical study of the behavior of a Ti-Cr-V compound while the second is a mechanical modelling and analysis mainly by the Discretes Elements Method (DEM). Thanks to this work the main features and mechanical properties of the hydride (granulometry, matrix compaction, granular flow, powder density …) and their evolution due to cycling were measured. The influence of hydride grains rearrangement induced by hydride breathing were analysed experimentally. It lead to a progressive densification of the powder bed in instrumented cells that resulted in a decrease of porosity and an increase of stresses on cell walls. This effect was reproduced in discrete elements simulations of spherical and clump particles

Causa regaliae penitus explicata seu Responsio ad dissertationem R.P.F. Natalis Alexandri De jure regaliae

Obra perteneciente al Fondo Antiguo de la Biblioteca de la USA

Etude du comportement mécanique d'un hydrure intermétallique utilisé pour le stokage d'hydrogène

It is harder and harder to find fossil fuels and it becomes therefore more and more expensive. Furthermore the environmental impacts of energy are more and more taken into account. For those reasons new solutions to produce, store, transport energy are currently researched and/or developed. Among those solutions, hydrogen system could be a good solution depending and how its main parts (production, storage, supply and use) are improved.This PhD is relative to hydrogen storage in intermetallic hydride compouds. Hydrogen tanks using these kind of materials have to allow good thermal control of the hydride powder especially because of the exothermicity of the hydriding and endothermicity of the unhydriding reaction. That's why the internal architecture of these vessels are often cellular, the cell walls playing the role of a thermal conductor. If the thermal aspects relative to these tanks are often studied, it is not the case of the mechanical phenomenon induced by the swelling and shrinking of the grains during absorption and desorption of hydrogène by the material. However, the mechanical interaction between the powder and the cell walls could endanger the tank.This PhD consists of two main parts. The first part is a mechanical study of the behavior of a Ti-Cr-V compound while the second is a mechanical modelling and analysis mainly by the Discretes Elements Method (DEM). Thanks to this work the main features and mechanical properties of the hydride (granulometry, matrix compaction, granular flow, powder density …) and their evolution due to cycling were measured. The influence of hydride grains rearrangement induced by hydride breathing were analysed experimentally. It lead to a progressive densification of the powder bed in instrumented cells that resulted in a decrease of porosity and an increase of stresses on cell walls. This effect was reproduced in discrete elements simulations of spherical and clump particles.La raréfaction des combustibles fossiles et la prise en compte de plus en plus importante des enjeux environnementaux incite à rechercher de nouvelles pistes de production, stockage et transport de l’énergie. Le développement de la filière hydrogène dépend des améliorations de chacun de ces principaux maillons qui sont la production, le stockage, la distribution et l’utilisation de l’hydrogène.Cette thèse se consacre au stockage de l’hydrogène par absorption dans des matériaux solides pulvérulents composés d’hydrures intermétalliques. Les performances de ce type de stockage dépendent grandement de la gestion des échanges de chaleurs imposés par le caractère exothermique de la réaction d’hydruration (absorption d’hydrogène par le matériau) et respectivement le caractère endothermique de la réaction de déshydruration (désorption d’hydrogène par le matériau). Cette nécessité a guidé la conception des réservoirs vers une architecture interne cellulaire. Si la thermique des réservoirs est très étudiée, les mécanismes de gonflement-dégonflement cycliques des hydrures lors de l’absorption et la désorption d’hydrogène sont assez peu abordés dans la littérature. Pourtant, les interactions mécaniques de la poudre hydrure sur les parois des cellules peuvent remettre en cause l’intégrité du réservoir. La mécanique des milieux granulaires constitue ainsi un apport essentiel à l’analyse et à termes à la prédiction du comportement mécanique du lit de poudre hydrure au sein du réservoir.Cette thèse présente en premier lieu la caractérisation expérimentale du comportement mécanique d’un hydrure intermétallique Ti-Cr-V à différents états de cyclage sous hydrogène en cellule instrumentée en incluant l’analyse des mécanismes de gonflement-dégonflement. L’analyse du comportement mécanique est abordée par une approche de type mécanique des milieux granulaires basée principalement sur la méthode des éléments discrets (DEM). Ces travaux ont permis d’identifier les caractéristiques et le comportement mécanique de l’hydrure (granulométrie, compression en matrice, écoulement) ainsi que l’évolution de paramètres liés au cyclage. Les effets du mécanisme de réarrangement opérant lors du cyclage à l’échelle des grains d’hydrure ont pu être identifiés expérimentalement. En particulier, la variation de volume cyclique du matériau entraine un tassement progressif du lit de poudre, une diminution de la porosité et une augmentation des niveaux de contraintes. Ce comportement a été reproduit numériquement par des simulations impliquant des particules discrètes de formes sphériques et de formes agrégées complexes

Tractatus De Libertatibvs Ecclesiæ Gallicanæ, Continens Amplam discussionem Declarationis factæ ab Illustrissimis Archiepiscopis, & Episcopis, Parisiis mandato Regio congregatis, anno M.DC.LXXXII. Avtore M. C. S. Theol. Doctore

TRACTATUS DE LIBERTATIBVS ECCLESIÆ GALLICANÆ, CONTINENS AMPLAM DISCUSSIONEM DECLARATIONIS FACTÆ AB ILLUSTRISSIMIS ARCHIEPISCOPIS, & EPISCOPIS, PARISIIS MANDATO REGIO CONGREGATIS, ANNO M.DC.LXXXII. AVTORE M. C. S. THEOL. DOCTORE Tractatus De Libertatibvs Ecclesiæ Gallicanæ, Continens Amplam discussionem Declarationis factæ ab Illustrissimis Archiepiscopis, & Episcopis, Parisiis mandato Regio congregatis, anno M.DC.LXXXII. Avtore M. C. S. Theol. Doctore (1) Einband (1) Kapitel (3) Tractatus De Libertatibus Ecclesiæ Gallicanæ. Lib. IV. (4) Tractatus De Libertatibus Ecclesiæ Gallicanæ. Lib. V. (50) Fotodokumentation (132

Causa regaliae penitus explicata, seu, Responsio ad dissertationem R.P.F. Natalis Alexandri de iure regaliae : quae habetur inter eius selecta historiae ecclesiasticae capita, ad saeculum XIII. & XIV, parte 3, a pagina 44. usque ad pag. 275

autore M.C. s. theologiae doctoreTitelseite zweifarbig (rot-schwarz) gedruck