Dissertationen zum Thema „Porosity Characterization“

The research work presented in this thesis is concerned with the production of porous components by using preceramic polymers as a starting precursor. During the preliminary studies on which the production of polymer derived cellular ceramics was based; various compositions have been investigated. Cellular SiOC ceramics having a complex morphology were produced using three different types of polysiloxane precursors. Pore formation was attributed to the different polymer architecture which resulted in a different behavior (larger weight loss, shrinkage and gas evolution) upon pyrolysis. In this context; polysiloxane precursors were crosslinked, crushed, sieved and pressed to form compacts yielding with porous SiOC monoliths by pyrolysis. The resulted ceramic bodies showed compressive strength values reaching to 37.4MPa (~53vol% porosity). Hot-isostatic pressing enabled the formation of SiOC(N) tablets having extremely high piezoresistivity in between 100-1700 at high temperatures (700-1000°C). By using a polysilazane precursor microcellular SiOCN and macrocellular SiCN foams were produced via sacrificial templating or a physical blowing agent. Foams had mostly interconnected porosity ranging from ~60 to 80 vol% and possessing a compressive strength in the range ~1 to 11 MPa. By following the similar strategies boron including porous (70 vol%) PDC monoliths have also been produced. In the direction to produce high specific surface area (SSA) hierarchically porous PDC components; Periodic Mesoporous Organosilica (PMO) particles were embedded into a foamed polysiloxane polymer, and by pyrolysis, permeable SiOC monoliths having SSA of 137 m2/g were obtained. In the method; catalyst assisted pyrolysis (CAP), silicon nitride, silicon oxynitride or silicon carbide nanowires were formed directly during the pyrolysis of highly porous monoliths. Increasing the pyrolysis temperature caused an increase in the length and the amount of nanostructures produced. The growth mechanisms for the nanowires depended on the pyrolysis conditions and catalyst type. The presence of the nanowires afforded high SSA values to the macro-porous ceramics, ranging from 10 to 110 m2/g. The differences were explained in terms of the morphology and amount of the nanowires that were produced using the two different catalysts (Co or Fe). High temperature etching of SiCN ceramics yielded with disordered or graphitic carbon materials possessing a hierarchical bi-modal pore structure (micro-mesopores with mean pore size, 3-11 nm) and large SSA, up to 2400 m2/g. The resulting porosity (pore size, PSD, and SSA) strongly depended on nanostructural phase evolution of the PDC material, as well as on etching conditions. The mean pore size increased with increasing pyrolysis temperature.
Il lavoro di ricerca esposto nella presente tesi riguarda la produzione di componenti porosi mediante l’uso di polimeri preceramici quali precursori iniziali. Durante una fase preliminare del lavoro di ricerca, sulla quale si è basata la produzione di ceramici cellulari derivati da polimeri, sono state studiate varie composizioni. Ceramici cellulari di SiOC aventi una morfologia complessa sono stati realizzati usando tre diversi tipi di precursori polisilossanici. La formazione di pori è stata attribuita alle differenti strutture dei polimeri, che hanno comportato differenti comportamenti durante la pirolisi (maggiore perdita in peso, diminuzione del volume e sviluppo di gas). In tale contesto, precursori polisilossanici sono stati reticolati, ridotti in polvere, setacciati e pressati al fine di ottenere campioni risultanti in monoliti di SiOC poroso, mediante pirolisi. I campioni ceramici cosí ottenuti esibivano valori di resistenza a compressione fino a 37,4 MPa (con una porosità pari a circa il 53% in volume). La pressatura isostatica a caldo ha consentito la formazione di campioni di SiOC(N) aventi piezoresistivitá estremamente elevata, compresa tra 100 e 1700 ad alte temperature (700-1000°C). Utilizzando un precursore polisilazanico, sono state prodotte schiume microcellulari di SiOCN e macrocellulari di SiCN, mediante l’impiego di fillers sacrificali o di un agente schiumante fisico. Le schiume presentavano una porosità prevalentemente interconnessa compresa tra ~60 e 80 vol% ed una resistenza a compressione compresa tra ~1 e 11 MPa. Utilizzando procedimenti simili, sono stati inoltre prodotti campioni monolitici porosi (70 vol%) di PDC contenenti boro. Al fine di produrre componenti ceramici derivati da polimeri, dotati di porosità gerarchica e di elevata area superficiale specifica (SSA), particelle di PMO (Periodic Mesoporous Organosilica) sono state immerse in un polimero polisilossanico schiumato e, mediante pirolisi, sono stati ottenuti campioni monolitici di SiOC permeabili dotati di una elevata SSA, pari a 137 m2/g. Mediante tale metodo, pirolisi catalizzata assistita (CAP), nanofili di nitruro di silicio, di ossinitruro di silicio o di carburo di silicio sono stati formati direttamente durante la pirolisi di campioni monolitici altamente porosi. L’aumento della temperatura di pirolisi ha provocato un aumento nella lunghezza e nella quantità di nanostrutture prodotte. Il meccanismo di crescita dei nanofili dipende dalle condizioni di pirolisi e dal tipo di catalizzatore. La presenza dei nanofili ha permesso di raggiugere elevati valori di SSA nei ceramici macroporosi, compresa tra 10 e 110 m2/g. Le diversità in tali valori sono state spiegate in termini di morfologia e quantità dei nanofili prodotti impiegando due diversi catalizzatori (Co e Fe). L’ablazione superficiale (etching) ad elevate temperature di ceramici di SiCN ha condotto a materiali contenenti carbonio amorfo o grafitico dotati di una struttura gerarchica bimodale dei pori (micro-mesopori con dimensione media dei pori di 3-11 nm) ed elevata SSA, fino a 2400 m2/g. La porosità risultante (dimensione dei pori, PSD e SSA) dipendeva fortemente dall’evoluzione della fase nanostrutturale del materiale PDC, nonché dalle condizioni di etching. La dimensione media dei pori aumentava all’aumentare della temperatura di pirolisi.

The Spraberry Formation is traditionally thought of as deep-water turbidites in the central Midland Basin. At Happy Spraberry field, Garza County, Texas, however, production is from a carbonate interval about 100 feet thick that has been correlated on seismic sections with the Leonardian aged, Lower Clear Fork Formation. The "Happy field" carbonates were deposited on the Eastern Shelf of the Midland Basin and consist of oolitic skeletal grainstones and packstones, rudstones and floatstones, in situ Tubiphytes bindstones, and laminated to rippled, very-fine grained siltstones and sandstones. The highest reservoir "quality" facies are in the oolitic grainstones and packstones where grain-moldic and solution-enhanced intergranular porosity dominate. Other pore types present include incomplete grain moldic, vuggy, and solution-enhanced intramatrix. The purpose of this study was to relate pore geometry measured by digital petrographic image analysis to petrophysical characteristics, and finally, to reservoir quality. Image analysis was utilized to obtain size, shape, frequency, and total abundance of pore categories. Pore geometry and percent porosity were obtained by capturing digital images from thin sections viewed under a petrographic microscope. The images were transferred to computer storage for processing with a commercial image analysis program trademarked as Image Pro Plus (Version 4.0). A classification scheme was derived from the image processing enabling "pore facies" to be established. Pore facies were then compared to measured porosity and permeability from core analyses to determine relative "quality" of reservoir zones with different pore facies. Pore facies are defined on pore types, sizes, shapes, and abundances that occur in reproducible associations or patterns. These patterns were compared with porosity and permeability values from core analyses. Four pore facies were identified in the Happy field carbonates; they were examined for evidence of diagenetic change, depositional signatures, and fractures. Once the genetic categories were established for the four pore facies, the pore groups could be reexamined in stratigraphic context and placed in the stratigraphic section across Happy field. Finally, the combined porosity and permeability values characteristic of each pore facies were used to identify and rank good, intermediate, and poor flow units at field scale.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
As pelotas de minério de ferro são uma das principais matérias-primas, juntamente com o minério granulado e o sínter, do processo de fabricação do aço. São produzidas pelo processo de pelotização, aproveitando a parcela ultrafina do minério, que antes era considerada rejeito do processo de beneficiamento. A porosidade gerada no processo de fabricação das pelotas é uma importante característica do material, pois permite o fluxo interno de gases, aumentando a sua redutibilidade e consequentemente a eficiência do processo. Por outro lado, a porosidade afeta a resistência física das pelotas, que precisam suportar todos os esforços sofridos durante as operações de manuseio, transporte e dos processos metalúrgicos. Dessa forma, a quantidade, tamanho, forma e a distribuição espacial dos poros são características importantes no controle de qualidade das pelotas, que são produzidas em grande escala e vem ganhando cada vez mais importância nas usinas siderúrgicas. Tradicionalmente, as técnicas analíticas mais utilizadas na caracterização da porosidade desses materiais são porosimetria por intrusão de mercúrio (PIM) e microscopia ótica (MO). A PIM só permite avaliar poros que estão conectados à superfície, além de utilizar o mercúrio que é um material volátil e tóxico, que oferece riscos ao meio ambiente e à saúde humana. A MO é limitada ao espaço bidimensional, podendo trazer informações pouco representativas. Ambas as técnicas são destrutivas, podendo degradar o material no processo de preparação e também impossibilitando análises posteriores numa mesma amostra. O presente trabalho propõe desenvolver uma metodologia de caracterização tridimensional de porosidade em pelotas de minério de ferro, envolvendo a técnica de microtomografia de raios X (MicroCT) e análise de imagens, a fim de estudar separadamente os diferentes tipos de poros (abertos e fechados), e comparar com as técnicas clássicas citadas anteriormente. Foram utilizadas 25 amostras cedidas pela Vale, analisadas Augusto, Karen Soares; Paciornik, Sidnei. Microtomografia Computadorizada de Raios X Aplicada à Caracterização de Porosidade em Pelotas de Minério de Ferro. Rio de Janeiro, 2016. 156p. Tese de Doutorado – Departamento de Engenharia Química e de Materiais, Pontifícia Universidade Católica do Rio de Janeiro. primeiramente por MicroCT e posteriormente por PIM ou MO. Para tentativas de otimização, foram testados alguns parâmetros de análise em MicroCT, tais como o uso de lentes, diferentes configurações geométricas dos dispositivos que compõem o equipamento e número de projeções, que afetam diretamente a resolução e o tempo de análise. Comparou-se os resultados obtidos em MicroCT com os obtidos por PIM e MO, em amostras equivalentes, observando-se valores menores de porosidade para a técnica de MicroCT, devido à pior resolução do sistema. Porém, a metodologia apresentada foi capaz de quantificar a porosidade aberta e fechada separadamente, descrever a distribuição espacial, além de medir tamanho e forma, dos poros.
Iron ore pellets are one of the major iron-bearing raw materials, along with lump ore and sinter, for the steelmaking processes. Pellets are produced from ultrafine fractions of iron ores, which were previously considered as tailings of mineral beneficiation. The porosity generated during the pelletizing process is an important characteristic of the material because it allows internal gas flow, increasing its reducibility and consequently the process efficiency. On the other hand, the porosity affects the physical strength of the pellets, which must withstand all loads during handling operations, transportation and metallurgical processes. Thus, the amount, size, shape and spatial distribution of pores are important features for the pellet quality control. Traditionally, most analytical techniques used to characterize the porosity of pellets are mercury intrusion porosimetry (MIP) and optical microscopy (OM). Nevertheless, MIP allows evaluating only pores connected to the surface, in addition mercury is volatile and toxic, offering risks to the environment and human health. OM, in turn, is limited to two-dimensional space and can reveal unrepresentative information. Both techniques are destructive and consequently prevent further analysis of the same sample. The present work proposes the development of a methodology for the tridimensional characterization of the porosity in iron ore pellets through X-ray microtomography (MicroCT) and image analysis in order to separately determine the different types of pores (open and closed). 25 samples provided by the Vale mining company were first analyzed by MicroCT and then by MIP or OM. For optimization purposes, some operating parameters of MicroCT were tested, such as the use of lenses, different geometric configurations, and the number of projections, which directly affect the obtained image resolution and the analysis time. Comparing the results obtained in MicroCT with the results obtained by MIP and OM in equivalent samples, smaller porosity measurements were observed for MicroCT, due to the poorer resolution of the system. However, this methodology has been able to separately quantify the open and closed porosity, to describe the spatial distribution of pores, and to measure their size and shape.

Graphite foams have high bulk thermal conductivity and low density, making them an excellent material for heat exchanger applications. This research focused on the characterization of graphite foams under various processing conditions (different foaming pressures and particle additions), specifically studying the effects of porosity on the thermal properties. The characterization of the foams included measuring cell sizes, percent open porosity, number of cells per square inch, bulk density, Archimedes density, compression strength, thermal conductivity, thermal resistance, and permeability. Several relationships between the structure and properties were established, and a recommendation for the processing conditions of graphite foams for the use in heat exchangers was determined.
Master of Science

The aim of this work was the generation of carbon materials with high surface area, exhibiting a hierarchical pore system in the macro- and mesorange. Such a pore system facilitates the transport through the material and enhances the interaction with the carbon matrix (macropores are pores with diameters > 50 nm, mesopores between 2 – 50 nm). Thereto, new strategies for the synthesis of novel carbon materials with designed porosity were developed that are in particular useful for the storage of energy. Besides the porosity, it is the graphene structure itself that determines the properties of a carbon material. Non-graphitic carbon materials usually exhibit a quite large degree of disorder with many defects in the graphene structure, and thus exhibit inherent microporosity (d < 2nm). These pores are traps and oppose reversible interaction with the carbon matrix. Furthermore they reduce the stability and conductivity of the carbon material, which was undesired for the proposed applications. As one part of this work, the graphene structures of different non-graphitic carbon materials were studied in detail using a novel wide-angle x-ray scattering model that allowed precise information about the nature of the carbon building units (graphene stacks). Different carbon precursors were evaluated regarding their potential use for the synthesis shown in this work, whereas mesophase pitch proved to be advantageous when a less disordered carbon microstructure is desired. By using mesophase pitch as carbon precursor, two templating strategies were developed using the nanocasting approach. The synthesized (monolithic) materials combined for the first time the advantages of a hierarchical interconnected pore system in the macro- and mesorange with the advantages of mesophase pitch as carbon precursor. In the first case, hierarchical macro- / mesoporous carbon monoliths were synthesized by replication of hard (silica) templates. Thus, a suitable synthesis procedure was developed that allowed the infiltration of the template with the hardly soluble carbon precursor. In the second case, hierarchical macro- / mesoporous carbon materials were synthesized by a novel soft-templating technique, taking advantage of the phase separation (spinodal decomposition) between mesophase pitch and polystyrene. The synthesis also allowed the generation of monolithic samples and incorporation of functional nanoparticles into the material. The synthesized materials showed excellent properties as an anode material in lithium batteries and support material for supercapacitors.
Kohlenstoffmaterialien finden aufgrund ihrer Vielseitigkeit heute in den unterschiedlichsten Bereichen des täglichen Lebens ihren Einsatz. Bekannte Beispiele sind Kohlenstofffasern in Verbundwerkstoffen, Graphit als trockenes Schmiermittel, oder Aktivkohlen in Filtersystemen. Ferner wird Graphit als Elektrodenmaterial auch in Lithium-Ionen-Batterien verwendet. Wegen knapper werdender Ressourcen von Öl und Gas wurde in den letzten Jahren verstärkt an der Entwicklung neuer Materialien für die Speicherung von Wasserstoff und elektrischer Energie gearbeitet. Die Nanotechnologie ist dabei auch für neue Kohlenstoffmaterialien zukunftsweisend, denn sie stellt weitere Anwendungsmöglichkeiten in Aussicht. In dieser Arbeit wurden hierzu mittels des sogenannten Nanocastings neue Kohlenstoffmaterialien für Energieanwendungen, insbesondere zur Speicherung von elektrischer Energie entwickelt. Die Eigenschaften eines Kohlenstoffmaterials beruhen im Wesentlichen auf der Struktur des Kohlenstoffs im molekularen Bereich. Die in dieser Arbeit hergestellten Materialen bestehen aus nichtgraphitischem Kohlenstoff und wurden im ersten Teil der Arbeit mit den Methoden der Röntgenstreuung genau untersucht. Eine speziell für diese Art von Kohlenstoffen kürzlich entwickelte Modellfunktion wurde dazu an die experimentellen Streubilder angepasst. Das verwendete Modell basiert dabei auf den wesentlichen Strukturmerkmalen von nichtgraphitischem Kohlenstoff und ermöglichte von daher eine detaillierte Beschreibung der Materialien. Im Gegensatz zu den meisten nichtgraphitischen Kohlenstoffen konnte gezeigt werden, dass die Verwendung von Mesophasen-Pech als Vorläufersubstanz (Precursor) ein Material mit vergleichsweise geringem Grad an Unordnung ermöglicht. Solch ein Material erlaubt eine ähnlich reversible Einlagerung von Lithium-Ionen wie Graphit, weist aber gleichzeitig wegen des nichtgraphitischen Charakters eine deutlich höhere Speicherfähigkeit auf. Zur Beschreibung der Porosität eines Materials verwendet man die Begriffe der Makro-, Meso-, und Mikroporen. Die Aktivität eines Materials kann durch die Erhöhung der Oberfläche noch erheblich gesteigert werden. Hohe Oberflächen können insbesondere durch die Schaffung von Poren im Nanometerbereich erzielt werden. Um die Zugänglichkeit zu diesen Poren zu steigern, weist ein Material idealerweise zusätzlich ein kontinuierliches makroporöses Transportsystem (Porendurchmesser d > 50 nm) auf. Solch eine Art von Porosität über mehrere Größenordnungen wird allgemein als „hierarchische Porosität“ bezeichnet. Für elektrochemische Anwendungen sind sogenannte Mesoporen (d = 2 – 50 nm) relevant, da noch kleinere Poren (Mikroporen, d < 2 nm) z.B. zu einer irreversiblen Bindung von Lithium- Ionen führen können. Wird Mesophasen-Pech als Kohlenstoffprekursor verwendet, kann die Entstehung dieser Mikroporen verhindert werden. Im zweiten und dritten Teil der Arbeit konnte mit den Methoden des „Nanocastings“ zum ersten Mal die spezielle Struktur des Mesophasen-Pech basierenden Kohlenstoffmaterials mit den Vorteilen einer hierarchischen (makro- / meso-) Porosität kombiniert werden. Im ersten Syntheseverfahren wurde dazu ein sogenanntes „hartes Templat“ mit entsprechender Porosität aus Siliziumdioxid repliziert. Aufgrund der hohen Viskosität des Pechs und der geringen Löslichkeit wurde dazu ein Verfahren entwickelt, das die Infiltration des Templates auch auf der Nanometerebene ermöglicht. Das Material konnte in Form größerer Körper (Monolithen) hergestellt werden, die im Vergleich zu Pulvern eine bessere technische Verwendung ermöglichen. Im zweiten Syntheseverfahren konnte die Herstellung eines hierarchisch makro- / mesoporösen Kohlenstoffmaterials erstmals mittels eines weichen Templates (organisches Polymer) erreicht werden. Die einfache Entfernung von weichen Templaten durch eine geeignete Temperaturbehandlung, macht dieses Verfahren im Vergleich zu hart templatierten Materialien kostengünstiger und stellt eine technische Umsetzung in Aussicht. Desweiteren erlaubt das Syntheseverfahren die Herstellung von monolithischen Körpern und die Einbindung funktionaler Nanopartikel. Die hergestellten Materialien zeigen exzellente Eigenschaften als Elektrodenmaterial in Lithium-Ionen-Batterien und als Trägermaterial für Superkondensatoren.

La grande majorité des procédés chimiques de transformation sont catalytiques. En catalyse hétérogène, les catalyseurs industriels sont des objets dont la taille est de l'ordre du millimétre au centimètre. Pour la plupart des catalyseurs, la phase active (ex: nanoparticules métallique) est dispersée dans un support mésoporeux ayant une surface spécifique élevé. Pour pallier au problème de limitation diffusionelle interne, on introduit dans le support un réseau secondaire de macropores qui permet d'améliorer la diffusion des substrats. Cependant, dans le cas où la réaction catalytique est particulièrement rapide, la diffusion à l'intérieur du support poreux peut rester limitante (Thiele modulus), entrainant une perte d'efficacité du catalyseur. L'objectif de ce travail de thèse est d'étudier l'efficacité d'un nouveau support alumine sous forme de bille dont la macroporosité est orientée de façon radiale. Afin de pouvoir quantifier le gain de cette nouvelle structure poreuse, des mesures d'activités pour deux réactions catalytiques modèles, l'oxydation de CO et le craquage de l'iso-octane, ont été réalisées et comparées à ceux de supports commerciaux et de références à porosité hiérarchisée. Pour les deux réactions, le nouveau support permet d'augmenter l'activité de 25 à 95% environ. Sur la base d'une caractérisation fine de la porosité des billes (adsorption N2-77k, porosimetrie à Hg, Tomographie RX), l'activité des catalyseurs a été modélisée. On conclut que le gain d'activité est essentiellement dû à la structuration radiale
The vast majority of chemical processes are catalytic. Within the heterogeneous catalysis, industrial catalysts are bodies whose size ranges between 1 mm to 1 cm. For most catalysts, the active phase (i.e. metal nanoparticles) is dispersed in a mesoporous support having a high specific surface area. To overcome the problem of internal diffusional limitation, a secondary network of macropores is introduced within the catalyst support. This improves the diffusion of substrates. However, in the case where the catalytic reaction is particularly fast, the diffusion inside the porous support can remain limiting (Thiele modulus), resulting in a loss of catalytic effectiveness. The objective of this thesis is to study the catalytic effectiveness of a new alumina-based support shaped into spherical pellets, owing a radial macroporosity. In order to quantify the impact of this new porous structure, two model catalytic reactions were chosen to test the catalysts: CO oxidation and isooctane cracking. The catalytic activity was compared to reference commercial supports owing hierarchical porosity. For both reactions, the new support with radial porosity increases the activity from 25 to 95% approximately. On the basis of a fine characterization of the porosity of the beads (adsorption N2-77k, porosimetry Hg, X-ray microtomography), the catalytic activities were modeled. We conclude that the impact on the catalytic activity is essentially due to the radial porous design

Process dependent microstructural effects in ferroelectric SrBi2Ta2O9 (SBT) thin films were characterized and distinguished from material dependent optical properties using a systematic multi-layer modeling technique. Variable angle spectroscopic ellipsometry (VASE) models were developed by sequentially testing Bruggeman effective-media approximation (EMA) layers designed to simulate microstructural effects such as surface roughness, porosity, secondary phases, and substrate interaction. Cross-sectional analysis by atomic force microscopy (AFM), transmission and scanning electron microscopy (TEM) and (SEM) guided and confirmed the structure of multi-layer models for films produced by pulsed laser deposition (PLD), metal-organic chemical vapor decomposition (MOCVD), and metal-organic deposition (MOD). VASE was used to estimated the volume percentage of second phase Bi2O3 in SBT thin films made by MOD. Since Bi₂O₃ was 10 orders of magnitude more conductive than SBT, second phase Bi₂O₃ produced elevated leakage currents. Equivalent circuits and percolation theory were applied to predict leakage current based on Bi₂O₃ content and connectivity. The complex role of excess Bi2O3 in the crystallization of SBT was reviewed from a processing perspective. VASE helped clarify the nature of the interaction between SBT films and Si substrates. When SBT was deposited by MOD and annealed on Si substrates, the measured capacitance was reduced from that of SBT on Pt due mainly to the formation of amorphous SiO₂ near the SBT/Si interface. VASE showed that the thickness and roughness of the SiO₂ reaction layer increased with annealing temperature, in agreement with TEM measurements. Unlike PZT, SBT crystallization was not controlled by substrate interaction.
Master of Science

The objective of this study is to characterize the properties of typically adopted drainage layer materials in VA, OK, and ID. A series of laboratory tests have been conducted to quantify the volumetric properties, permeability and mechanical properties of the laboratory-compacted asphalt treated and cement treated permeable base specimens. The modified test protocols to determine the dynamic modulus of the drainage layer materials have been provided, which can be followed to determine the dynamic modulus of the drainage layers as level 1 input in Mechanistic-Empirical (M-E) pavement design. The measured dynamic moduli have been used to calibrate the original NCHRP 1-37A model to facilitate its application on drainage layer materials for prediction of the dynamic modulus as level 2 input. The compressive strength of the cement treated permeable base mixture of different air void contents has also been quantified in laboratory. Numerical simulations are conducted to investigate the location effects and the contribution of the drainage layer as a structural component within pavement. The optimal air void content of the drainage layer is recommended for Virginia, Oklahoma and Idaho based on the laboratory-determined permeability and the predicted pavement performances during 20-year service life.
Ph. D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references.
The process of charging a polymer solution to draw a filament is known as electrospinning. Electrospinning is capable of producing a continuously depositing jet of controllable micron and sub-micron diameters. As fiber deposits, a nonwoven mat of randomly oriented fibers in two dimensions is generated. The mat is mechanically robust and suitable for a wide variety of applications due to its high surface area to mass ratio, controllable size scale and surface chemistry, and large void fraction. The number of publications on the topic of electrospinning continues to grow exponentially, as the experimental apparatus is relatively inexpensive to assemble and 1 mm thick fiber mats can be generated in as little as 2 hours. Many publications have focused on potential applications or the processing of specific materials. Some publications have reported on the hydrodynamics and physics of the electrospinning process, leading to an increased control of fiber diameter and morphology. One area that remains relatively unexplored is pore diameter and porosity within the fiber mat. The present work explores characterizing and controlling void space in electrospun materials and the use of these materials in the field of tissue engineering. Characterization and prediction of overall void fraction and individual pore diameter is first addressed. Mercury porosimetry was used to establish two physical parameters useful in electrospinning applications: average pore diameter and peak pore diameter. Average pore diameter refers to the volume-weighted average determined by the volumetric profile. Peak pore diameter is the pore diameter at which the largest amount of void volume becomes accessible.
(cont.) The accuracy of mercury porosimetry was also addressed, leading to a method of data correction for buckling of pores under the significant pressure generated by mercury porosimetry. Having characterized and predicted the void statistics for as-spun materials, the second portion of this work sought to use post-processing techniques to alter the effective pore diameter. Two components - poly(E-caprolactone) and poly(ethylene oxide) - were electrospun together, either from a common polymer solution or adjacent fluid jets on to a common target. Water was used to selectively remove the poly(ethylene oxide) component in both systems, with vastly different results. Mats electrospun from a common solution saw an increasing reduction in the void diameter with increasing poly(ethylene oxide) removal due to poly(E-caprolactone) chain rearrangement and contraction of the polymer fibers, up to a pore diameter reduction of 80%. Mats produced by the dual jet method saw both an increase and decrease of the effective pore diameter depending on processing conditions. These experiments represent the first steps by researchers to specifically tailor pore diameter independent of porosity or fiber diameter. The final portion of this thesis deals with the use of electrospun materials as 3-Dimensional tissue engineering scaffolds. An effective perfusion technique was developed for the seeding and infiltration of cells into multiple electrospun mats simultaneously, with 100% efficiency. This represents an enormous advantage over conventional seeding methods.
(cont.) Human Dermal Fibroblasts were seeded into scaffolds of drastically varied fiber diameter (300nm to 8 [mu]m) and morphology (beaded vs. uniform diameter). Despite cells spreading along large fibers instead of developing multiple attachment points between fibers, cell proliferation was greatest in scaffolds with pore diameters greater than 6 [mu]m. At the same time, mats with pore diameters less than 12 pm observed the greatest extracellular matrix growth. Additional investigation would be well-served to determine optimal parameters for cell dispersion and reproduction throughout the electrospun template across multiple cell phenotypes.
by Joseph Lenning Lowery.
Ph.D.

Mestrado Vinifera EuroMaster - Instituto Superior de Agronomia
The objective of this work is to describe and compare colmated and non-colmated stoppers cork stoppers, regarding their differences in appearance (image analysis), structure (analysis with scanning electron microscopy- SEM), and mechanical behavior (compression test). For this study 75 natural cork stoppers were used and divided equally in 3 groups: (i) stoppers of superior class; (ii) stoppers of inferior class to be colmated; (iii) colmated stoppers. Image analysis techniques were applied on the surfaces of superior and inferior (pre-colmated) class of stoppers, to analyze their porosity. Porosity features showed differences between two classes: higher values of all features in the inferior class and lower in the superior quality class. Water absorption test performed on colmated and pre-colmated group of stoppers showed small differences between them: colmated stoppers absorbed less water (92.1%) than pre-colmated class (98.8%) and the same trend was found with dimensional variations (swelling) (lower swelling of colmated stoppers was reported). The behavior of the colmated and pre-colmated stoppers under compression performed in axial and radial direction was studied. Young’s modulus for compression in axial direction were 21.2 MPa and 18.4 MPa for colmated and pre-colmated group respectively, while the compression in radial direction was characterized with the range of force for the given deformation, with mean values of 147 kN and 135 kN for 1 mm deformation. Colmated stoppers were additionally analyzed by SEM, where the observations emphasis was given to the colmation material impregnation in the interior of the stoppers. Colmation material presence was mainly reported on the stoppers surface. It can be concluded that colmation process primarily improves the appearance of the stopper, covering successfully the undesirable surface pores, which is the main objective of the colmation.

The topic of this Philosophy Doctor Thesis tallies with the national project MAT2012 of the BBT group of UPC: "Pore4Bone: Biomimetic calcium phosphates: tailoring porosity from the nano- to the macroscale for osteoinduction, drug delivery and bone tissue engineering". Bone is one of the most transplanted tissues globally, with around one million surgical procedures each year. Ageing of the population worldwide requires intense effort in designing efficient, clinically applicable multifunctional biomaterials for bone regeneration. The need for a higher volume of bone graft, and advanced solutions make synthetic bone grafts an attractive alternative to auto- or xenografts. Synthetic calcium phosphate cements (CPCs) provide a high freedom of processing and conformation, and excellent biomimicry to natural bone. Biocompatible and osteoconductive per se , CPCs support in vivo remodeling of bone. The intrinsic micro- and nano- porosity of CPCs resulting from the spaces between the entangled crystals and aggregates once set is a key property when considering bone regeneration and local release of drugs. It provides free space for drug diffusion and fluid penetration, both of which are essential elements for drug release. Thus, a comprehensive characterization of the porosity, especially at the microscopic and nanoscopic scale is of paramount interest to identify these mechanisms, so it has been tackled in detail in this work. Focusing on bone infections, the combination of antibiotics with osteogenic matrices like CPCs is explored in the PhD Thesis. Indeed, while bone infections and bone disorders are generally treated post-operatively by systemic administration of the indicated antibiotic, achieving a therapeutically efficient local delivery of the active principles is a key challenge, as it allows reducing secondary unwanted effects, drug interactions and diminishing the required dose due to the enhanced local bioavailability. In particular, the relationship between antibiotic addition, porosity and drug release in calcium phosphate cements (CPCs) is highlighted and studied in this PhD Thesis. Finally the introduction of macropores in CPCs is investigated to manufacture antibiotic-releasing calcium phosphate foams (CPFs) for bone regeneration, which present clear clinical benefits over CPCs as multifunctional biomaterials. Indeed, the clinical performance of CPCs as local drug delivery devices is restricted by the relatively low penetration of corporal fluids through their micro or nanopores, preventing a complete release of the drug. The slow release of the entrapped antibiotic during the degradation of the CPC may generate a local concentration below the minimum inhibitory concentration, with the risk to foster the development of antibiotic-resistant bacteria. The addition of a network of interconnected macropores in CPCs represents a major advance by enhancing fluid circulation, and the consequent increase of the release rate of the antibiotic. Thus, in addition to the injectability and biomimicry of CPCs, the interconnected macroporosity of CPFs endows these materials with clear advantages not only in terms of tuning the release kinetics of active principles, but also when considering their excellent osteogenic properties.
La presente Tesis doctoral se enmarca dentro del proyecto MAT2012 del grupo de investigación BBT de la UPC: "Pore4Bone: Biomimetic calcium phosphates: tailoring porosity from the nano- to the macroscale for osteoinduction, drug delivery and bone tissue engineering" financiado por el Gobierno de España. El hueso es uno de los tejidos más trasplantados mundialmente con hasta 1 millón de cirugías anuales. El envejecimiento de la población conlleva la necesidad de hacer grandes esfuerzos en el diseño de biomateriales multifuncionales, eficientes y clínicamente aplicables a la regeneración ósea. El aumento del número de injertos óseos necesarios y la necesidad de encontrar soluciones avanzadas hace que los biomateriales sintéticos sean una alternativa atractiva a los auto- o xeno- injertos actuales. Los cementos de fosfato de calcio (CPCs) son materiales muy versátiles en cuanto a los procesos de conformado, y presentan propiedades muy similares a las del hueso natural. Siendo materiales biocompatibles y osteoconductivos, los CPCs actúan de soporte al proceso de remodelación ósea in vivo . Además, los CPCs presentan una micro- y nano- porosidad intrínseca, que tiene su origen en los espacios entre los cristales que se forman tras el fraguado. Dicha porosidad es de gran relevancia en la regeneración ósea y la liberación local de fármacos, al proporcionar espacios disponibles para la difusión de los fármacos y la circulación de fluidos corporales, ambos procesos esenciales para la liberación del principio activo. En esta Tesis Doctoral se ha abordado la caracterización de la porosidad de los CPCs en profundidad, especialmente a escala micro- y nanoscópica, por ser de gran interés en la identificación de los mecanismos de regeneración ósea y liberación controlada de fármacos. En el caso de las infecciones óseas, en la presente Tesis Doctoral se explora la combinación de antibióticos con matrices bioactivas como los CPCs. Así, mientras las infecciones óseas se tratan habitualmente mediante la administración sistémica de antibióticos de forma post-operatoria, alcanzar una liberación local eficaz del principio activo es un reto clave, que permitiría reducir los efectos secundarios no deseados, minimizar las interacciones potenciales entre fármacos y disminuir la dosis necesaria, gracias a una mayor biodisponibilidad. En este Trabajo, se ha estudiado en profundidad la relación entre la incorporación de antibiótico, la porosidad y la liberación de fármaco en cementos de fosfato de calcio (CPCs). Además, se ha investigado la introducción de macroporosidad en los CPCs con el objetivo de fabricar espumas de fosfato de calcio (CPFs) capaces de liberar fármacos para regeneración ósea a nivel local, con claras ventajas frente a los CPCs como biomateriales multifuncionales. En efecto, la eficacia clínica de los CPCs como dispositivos de liberación local de fármacos está limitada por la relativamente baja penetración y circulación de los fluidos corporales en los mismos, impidiendo una liberación completa del fármaco. El riesgo de que el antibiótico atrapado en el material se libere lentamente durante la degradación del mismo, dando lugar a concentraciones locales de antibiótico inferiores a la concentración mínima inhibitoria, puede llevar a la generación de resistencia bacteriana al antibiótico. La adición de una red de macroporos interconectados en los CPFs representa un avance importante, puesto que aumenta la circulación de fluidos corporales en el biomaterial, incrementa el control sobre la cinética de liberación de fármacos y permite colonización celular. Así pues, los CPFs junto a la inyectabilidad y el biomimetismo de los CPCs, presentan a una macroporosidad interconectada que les confiere un elevado interés en vistas tanto a la regeneración ósea como a la liberación local de fármacos.

The present study deals with the physical characterization of macrodefect free cements produced by ICI. These materials are made through a specialized mixing technique which incorporates an organic polymer into the cement/water system. The high mechanical strength and low porosity of this class of hardened cement paste had been well documented, however, a detailed characterization of the physical nature of the microstructure had not previously been attempted. Two classes of macrodefect free material were studied, based on Ordinary Portland cement and High Alumina cement, respectively. The porosities of these two materials were determined in their original state and after various forms of heat treatment and conditioning. Samples based on Ordinary Portland cement had a well defined narrow pore size distribution, even after heat treatment, while the High Alumina cement samples displayed a very low total pore volume in their original state, but subsequent heat treatment led to the developement of porosity over a wide range of pore sizes. These fundamental differences in the pore size distributions had significant effects on the homogeneity and reproducibility of the microstructures of the samples. The porosity generated by heat treatment was found to be unstable in the presence of water. In general, reductions in the porosities and permeabilities were observed. This was due to the formation of fresh cement hydrate gel within the pore structure, which caused a shift in the pore size distributions towards smaller pores.

>Magister Scientiae - MSc
The Bredasdorp Basin was formed consequent to extensional episodes during the initial stages of rifting in the Jurassic age. The basin acted as a local depocentre and was primarily infilled with late Jurassic and early Cretaceous shallow-marine and continental sediments. Two wells namely; D-D1 and E-AP1 were studied in order to evaluate the petrophysics and characterize sandstone reservoirs of the western Bredasdorp basin. This could be achieved by generating and comparing results from core analysis and wireline in order to determine if the two wells are comprised of good quality sandstone reservoirs and if the identified reservoirs produce hydrocarbons. A number of methods were employed in order to characterise and evaluate sandstone reservoir, these included; editing and normalization of raw wireline log data ,classification of lithofacies on the basis of lithology, sedimentary structures, facies distribution, grain size variation, sorting of grains, fossils and bioturbation; calibration of log and core data to determine parameters for petrophysical interpretation; volume of clay; determination of porosity, permeability and fluid saturation, cut-off determination to distinguish between pay and non-pay sands. Borehole D-D1 is located in the western part of the Bredasdorp Basin. Only two reservoirs in well D-D1 indicated to have pay parameters with an average porosity ranging from 11.3% to 16%, average saturation from 0.6% to 21.5% and an volume of clay from 26.5% to 31.5%. This well was abandoned due to poor oil shows according to the geological well completion report. On the contrary well E-AP1 situated in the northwestern section of the basin showed good quality reservoir sandstones occurring in the 19082m to 26963m intervals though predominantly water saturated. Pay parameters for all five reservoirs in this well showed zero or no average porosity, saturation and volume of clay.

This research studies the chemical nature of zirconia and the complex surface chemistry of zirconia in order to better comprehend its behavior under chromatographic conditions. This research shows how the physical and chemical properties of zirconia depend strongly on the thermal treatment during synthesis. The morphology of the samples was also studied. The absorption capability of Adenosine Triphosphate (ATP) on zirconia was also monitored and spectrally characterized. The results of this research showed how the properties of zirconia vary with thermal treatment. It was observed that the zirconia prepared at a higher temperature had lower surface area, lower pore size and pore volume as compared to the zirconia prepared at a lower temperature. The morphology studies showed the porosity of the zirconia. The results from the absorption experiments showed that zirconia prepared at a higher temperature absorbed more ATP than the zirconia prepared at a lower temperature. Significant changes were also observed on the pellets of zirconia pre and post absorption experiments. I hope that this research sheds more light on the complex properties of zirconia’s surface chemistry and the results of this study could better help in the application and use of zirconia in chromatography to separate proteins.

L'un des objectifs de l'industrie éolienne est de produire de grandes pièces de structure à moindre coût. Dans ce contexte, la fabrication de pièces composites à partir de renforts quasi unidirectionnels(quasi-UD NCF) avec le procédé d’infusion est compétitive tant sur le plan mécanique que financier. Le procédé d'infusion engendre un phénomène de décompaction dû à la flexibilité de la bâche à vide. De plus les NCF présentent un écoulement à double échelle pendant leur imprégnation. La modélisation des deux phénomènes est souvent réalisée en supposant que la préforme fibreuse est un milieu continu à perméabilité variable. Néanmoins, la perméabilité est influencée par la répartition et la taille des mésopores, qui dépendent de l'état de compaction. Le but de cette thèse est de caractériser expérimentalement l'évolution d'un quasi-UD lors de l’infusion et d’évaluer l'impact de la réorganisation microstructurale sur des quantités macroscopiques d’intérêt, tels que la perméabilité et le temps de remplissage des pièces.Des infusions ont été réalisées à l'intérieur d'un tomographe pour capter l’évolution d’une même microstructure avant et après infusion. Un modèle simplifié a été proposé pour prédire la perméabilité dans le plan et ainsi évaluer l'influence de la réorganisation microstructurelle sur celle-ci. De plus,un outil numérique a été développé pour prendre en compte un écoulement double échelle dans un milieu fibreux déformable bidisperse. L'impact de la décompaction sur le temps de remplissage des pièces a été établi. Une étude mécanique expérimentale du comportement de la mèche tout au long de l’infusion a également été réalisée afin de mieux comprendre le comportement du quasi-UD. Un modèle hyperélastique a finalement été proposé pour prédire le comportement mécanique 3D des mèches pendant la phase de chargement à sec, avant l'infusion
A current aim of wind turbine industries is to produce large structural parts at reduced costs. In this context, manufacture composite blades made of quasi-unidirectional non-crimp fabrics (quasi-UD NCF) using the infusion process is competitive on both mechanical and cost aspects. The infusion process involves an unloading phenomenon due to the vacuum bag flexibility. Additionally, during the impregnation, NCFs exhibit a dual-scale flow. Usual modeling of both phenomena assumes that the fibrous preform is a continuous medium with a varying permeability. Nonetheless, the permeability is affected by the meso-pores size and spatial distribution, which depend on the compaction state. The goal of this thesis is thus to characterize experimentally the flow-induced microstructural evolution of a quasi-UD NCF during the infusion process, and to quantify the impact of thismicrostructural reorganization on relevant macroscopic parameters, such as modelled in-plane permeability as well as computed filling time of parts. In situ infusion process has been conducted inside X-ray Computed Tomography device to capture a dual-scale fibrous microstructure prior and after the infusion process. Additionally, a simplified model has been proposed to predict the in-plane permeability and thus to evaluate the influence of the microstructural reorganization on it. Then, a numerical tool has been developed to account for dual-scale flow in a bidisperse deformable fibrous media. The impact of the dual-scale unloading on themacroscopic filling time of parts has been established. A mechanical investigation of the towbehavior during the infusion process has been additionally carried out experimentally to better understand the quasi-UD NCF behavior. From these results, a hyperelastic model has been proposed to predict the 3D mechanical behavior of tows during the dry loading phase, prior to the infusion process

Mesoporous γ-Al2O3 is one of the most widely used catalyst supports for commercial catalytic applications. The performance of a catalyst strongly depends on the combination of textural, chemical and physical properties of the support. Pore size is essential since each catalytic system requires a unique pore size for optimal catalyst loading, diffusion and selectivity. In addition, high surface area and large pore volume usually result in higher catalyst loading, which increases the number of catalytic reaction sites and decreases reaction time. Therefore, determination of surface area and porosity of porous supports is critical for the successful design and optimization of a catalyst support. Moreover, it is important to produce supports with good thermal stability since pore collapsing due to sintering at high temperatures often results in catalyst deactivation. In addition, the ability to control the acidity of the catalyst enables us to design desirable acid sites to optimize product selectivity, activity, and stability in different catalytic applications. This dissertation presents a simple, one-pot, solvent-deficient method to synthesize thermally stable silica-doped alumina (SDA) without using templates. The XRD (X-ray diffraction), HTXRD (high temperature X-ray diffraction), SS NMR (solid state nuclear magnetic resonance), TEM (transmission electron microscopy), TGA(thermogravimetric analysis), and N2 adosorption techniques are used to characterize the structures of the synthesized SDAs and understand the origin of increased thermal stability. The obtained SDAs have a surface area of 160 m2/g, pore volume of 0.99 cm3/g, and a bimodal pore size distribution of 23 and 52 nm after calcination at 1100◦C. Compared to a commercial SDA, the surface area, pore volume, and pore diameter of synthesized SDAs are higher by 46%, 155%, and 94%, respectively. A split-plot fractional-factorial experimental design is also used to obtain a useful mathematical model for the control of textural properties of SDAs with a reduced cost and number of experiments. The proposed quantitative models can predict optimal conditions to produce SDAs with high surface areas greater than 250 m2/g, large pore volume greater than 1 cm3/g, and large (40-60 nm) or medium (16-19 nm) pore diameters. In my approach, I control acid sites formation by altering preparation variables in the synthesis method such as Si/Al ratio and calcination temperatures. The total acidity concentration (Brønsted and Lewis) of the synthesized SDAs are determined using ammonia temperatured program, pyridine fourier transform infrared spectroscopy (FTIR), and MAS NMR. The total acidity concentration is increased by introducing a higher mole ratio of Si to Al. In addition, the total acidity concentration is decreased by increasing calcination temperature while maintaining high surface area, large porosity, and thermal stability of γ-alumina support. I also present an optimized synthesis of various aluminum alkoxides (aluminum n-hexyloxide (AH), aluminum phenoxide (APh) and aluminum isopropoxide (AIP)) with high yields (90-95%). One mole of aluminum is reacted with excess alcohol in the presence of 0.1 mole % mercuric chloride catalyst. The synthesized aluminum alkoxides are used as starting materials to produce high surface area alumina catalyst supports. Aluminum alkoxides and nano aluminas are analyzed by 1H NMR, 13C NMR, 27Al NMR, gCOSY (2D nuclear magnetic resonance spectroscopy), IR (infrared spectroscopy), XRD, ICP (induced coupled plasma), and elemental analysis.

It is perhaps paradoxical that many material properties arise from the absence of material rather than the presence of it. For example, the strength, stiffness, and toughness of a concrete are related to its pore structure. Furthermore, the volume, size distribution, and interconnectivity of porosity is important for understanding permeability, diffusivity, and capillary action occurring in concrete, which are necessary for predicting service lives in aggressive environments. This research advances the state-of-the-art of multiscale characterization of cement-based materials, and uses this characterization information to model the material behavior under competing durability concerns. In the first part of this research, a novel method is proposed to characterize the entrained air void system. In the second and third parts of this research, microstructural characterization is used in tandem with mechanical models to investigate the behavior of cementitious materials when exposed to rapid rates of loading and to cyclic freezing and thawing. First, a novel analytical technique is presented which reconstructs the 3D entrained air void distribution in hardened concrete using 2D image analysis. This method proposes a new spacing factor, which is believed to be more sensitive to microstructural changes than the current spacing factor commonly utilized in practiced, and specified in ASTM C457, as a measure of concrete's ability to resist to damage under cyclic freeze/thaw loading. This has the potential to improve economy by improving the quality of petrographic assessment and reducing the need for more expensive and time-consuming freeze/thaw tests, while also promoting the durability of concrete. Second, quantitative measurements of the sizes, shapes, and spatial arrangements of flaws which are through to drive failure at strain rates above 100/s were obtained in order to model mortar subjected to high strain-rate loading (i.e., extremes in load rate). A micromechanics model was used to study the ways in which flaw geometry and flaw interaction govern damage. A key finding suggests that dynamic strength may be multimodal, with larger flaws shifting the dynamic strength upwards into the highest strength failure mode. Third, a robust theoretical approach, based upon poroelasticity, is presented to further validate the utility of the novel spacing factor proposed this research. The model is truly multiscale, using in its formulation pore size data ranging from the nanoscale to the micro-scale, entrained air data from the micro-scale to the millimeter scale, and infers a representative volume element on the centimeter scale. The results provide an underlying physical basis for the performance of the novel spacing factor. Furthermore, the framework could be used as a forensic tool, or as a tool to optimize the entrained air void system against freeze/thaw damage.

Porous Ti-6Al-4V alloys are widely used in the biomedical applications for hard tissue implantation due to its biocompatibility and elastic modulus being close to that of bone. In this study, porous Ti-6Al-4V alloys were produced with a powder metallurgical process, space holder technique, where magnesium powders were utilized in order to generate porosities in the range of 50 to 70 vol. %. In the productions of Ti-6Al-4V foams, first, the spherical Ti-6Al-4V powders with an average size of 55 &mu
m were mixed with spherical magnesium powders sieved to an average size of 375 &mu
m, and then the mixtures were compacted with a hydraulic press under 500 MPa pressure by using a double-ended steel die and finaly, the green compacts were sintered at 1200

This dissertation presents the development of a method for quantitative integration of seismic (elastic) anisotropy attributes with reservoir performance data as an aid in characterization of systems of natural fractures in hydrocarbon reservoirs. This new method incorporates stochastic Discrete Feature Network (DFN) fracture modeling techniques, DFN model based fracture system hydraulic property and elastic anisotropy modeling, and non-linear inversion techniques, to achieve numerical integration of production data and seismic attributes for iterative refinement of initial trend and fracture intensity estimates. Although DFN modeling, flow simulation, and elastic anisotropy modeling are in themselves not new technologies, this dissertation represents the first known attempt to integrate advanced models for production performance and elastic anisotropy in fractured reservoirs using a rigorous mathematical inversion. The following new developments are presented: . • Forward modeling and sensitivity analysis of the upscaled hydraulic properties of realistic DFN fracture models through use of effective permeability modeling techniques. . • Forward modeling and sensitivity analysis of azimuthally variant seismic attributes based on the same DFN models. . • Development of a combined production and seismic data objective function and computation of sensitivity coefficients. . • Iterative model-based non-linear inversion of DFN fracture model trend and intensity through minimization of the combined objective function. This new technique is demonstrated on synthetic models with single and multiple fracture sets as well as differing background (host) reservoir hydraulic and elastic properties. Results on these synthetic control models show that, given a well conditioned initial DFN model and good quality field production and seismic observations, the integration procedure results in convergence of both fracture trend and intensity in models with both single and multiple fracture sets. Tests show that for a single fracture set convergence is accelerated when the combined objective function is used as compared to a similar technique using only production data in the objective function. Tests performed on multiple fracture sets show that, without the addition of seismic anisotropy, the model fails to converge. These tests validate the importance of the new process for use in more realistic reservoir models.

The central goal of this research is to quantitatively characterize the relationships between processing, microstructure, and mechanical properties of important high-pressure die-cast (HPDC) Mg-alloys. For this purpose, a new digital image processing technique for automatic detection and segmentation of gas and shrinkage pores in the cast microstructure is developed and it is applied to quantitatively characterize the effects of HPDC process parameters on the size distribution and spatial arrangement of porosity. To get better insights into detailed geometry and distribution of porosity and other microstructural features, an efficient and unbiased montage based serial sectioning technique is applied for reconstruction of three-dimensional microstructures. The quantitative microstructural data have been correlated to the HPDC process parameters and the mechanical properties. The analysis has led to hypothesis of formation of new type of shrinkage porosity called, gas induced shrinkage porosity that has been substantiated via simple heat transfer simulations. The presence of inverse surface macrosegregation has been also shown for the first time in the HPDC Mg-alloys. An image analysis based technique has been proposed for simulations of realistic virtual microstructures that have realistic complex pore morphologies. These virtual microstructures can be implemented in the object oriented finite elements framework to model the variability in the fracture sensitive mechanical properties of the HPDC alloys.

Among the most important properties controlling the production from conventional oil and gas reservoirs is the distribution of porosity and permeability within the producing geologic formation. The geometry of the pore space within these reservoirs, and the permeability associated with this pore space geometry, impacts not only where production can occur and at what flow rates but can also have significant influence on many other rock properties. Zones of high matrix porosity can result in an isotropic response for certain reservoir properties whereas aligned porosity/permeability, such as open, natural fracture trends, have been shown to result in reservoirs being anisotropic in many properties.

The ability to identify zones within a subsurface reservoir where porosity/permeability is significantly higher and to characterize them according to their geometries would be of great significance when planning where new boreholes, particularly horizontal boreholes, should be drilled. The detection and characterization of these high porosity/permeability zones using their isotropic and anisotropic responses may be possible through the analysis of azimuthal (also referred to as azimuth-limited) 3D seismic volumes.

During this study the porosity/permeability systems of a carbonate, pinnacle reef within the northern Michigan Basin undergoing enhanced oil recovery were investigated using selected seismic attributes extracted from azimuthal 3D seismic volumes. Based on the response of these seismic attributes an interpretation of the geometry of the porosity/permeability system within the reef was made. This interpretation was supported by well data that had been obtained during the primary production phase of the field. Additionally, 4D seismic data, obtained as part of the CO₂ based EOR project, supported reservoir simulation results that were based on the porosity/permeability interpretation.

Limestone is a raw material in the cement and quicklime industry and knowledge about limestone characteristics can help improve and optimize production processes. In the end this can lead to a reduction in CO2 emissions from the industry. In this project X-ray tomography (XRT) was used to examine limestone samples. The aim was to determine if XRT, including synchrotron-based XRT, is a reliablemethod to determine porosity, pore structure and internal distributions of pores and pyrite (FeS2) grains in limestone. The aim also included to determine if XRT could be used to resolve material variations, fine-grained and larger crystals in limestone. In total, there were ten limestone samples and the performed XRT was done by Advanced Light Source (ALS) in Berkeley, California and by Luleå University of Technology. A brief comparison between ALS and Luleå was also done by inspectingsamples that have been through XRT at both facilities. The main software used foranalysis was Avizo v.9.2.0. The results showed that XRT is a suitable method for determining porosity and pore distribution. Interactive thresholding was used in Avizo for measuring porosity. The porosity was determined as a single value and as a narrow range, where a narrow range was more reliable. XRT was also found to be a suitable method for visually determining a variety of textures within the samples. Areas with different materials(such as dolomite) and/or newly-formed crystals were visually distinguishable but individual newly-formed crystals were not as clear when compared to scanning electron microscopy. Individual older fine-grained and larger crystals were hard to resolve. Internal distributions in 3D of both pores and pyrite grains were possible to obtain with XRT. The analysis of internal distributions was found to be a clear advantage with the method of XRT. The equivalent diameter of pores and pyrite grains was also measured and plotted in histograms. The XRT performed at ALS had higher resolution than the XRT performed in Luleå (0.65 vs 2 μm). Lower resolution over-estimated the average equivalent diameter of pores, and boundaries of pores and cavities were harder to see. Therefore, the higher resolution from ALS was preferable. These results contribute to understanding limestone characteristics.

Rapid prototyping methods embrace a family of manufacturing methods that are developed to speed up the prototyping stage of product design. The sole needed input for production being the solid model of the part, mold/tool-free production characteristics and the geometric part complexity that can be achieved due to layer-by-layer production have extended the applicability/research areas of these methods beyond prototyping. Local pore formation in part that occurs as a result of the discrete manufacturing nature of rapid prototyping methods can be viewed as an opportunity for material development. In this thesis, the manufacturing-internal (porous) structure-mechanical property relations of porous materials are investigated. These porous parts are produced via Selective Laser Sintering (SLS) which is a rapid prototyping method. The elastic modulus, tensile strength, rupture strength and Poisson&rsquo
s ratio of uniform porous specimens with known porosities are determined through standardized mechanical tests for polymeric materials. The mechanical property variation profiles in graded materials are determined using the mechanical properties of uniform parts. The mechanical behavior of uniform and graded materials under applied loads are modeled using finite element method and simulation results are compared to the results of mechanical tests performed on graded materials. In addition, feasibility of producing resin filled composite parts from these uniform and graded porous parts are sought. Porous parts (both uniformly and graded) that are infiltrated with epoxy resin have been characterized mechanically and the results have been compared with the uninfiltrated porous parts.

>Magister Scientiae - MSc
The thesis aims to determine the depositional environments, rock types and petrophysical characteristics of the reservoirs in Wells E-S3, E-S5 and F-AH4 of Area X in the Bredasdorp Basin, offshore South Africa. The three wells were studied using methods including core description, petrophysical analysis, seismic facies and multivariate statistics in order to evaluate their reservoir potential. The thesis includes digital wireline log signatures, 2D seismic data, well data and core analysis from selected depths. Based on core description, five lithofacies were identified as claystone (HM1), fine to coarse grained sandstone (HM2), very fine to medium grained sandstone (HM3), fine to medium grained sandstone (HM4) and conglomerate (HM5). Deltaic and shallow marine depositional environments were also interpreted from the core description based on the sedimentary structures and ichnofossils. The results obtained from the petrophysical analysis indicate that the sandstone reservoirs show a relatively fair to good porosity (range 13-20 %), water saturation (range 17-45 %) and a predicted permeability (range 4- 108 mD) for Wells E-S3, E-S5 andF-AH4. The seismic facies model of the study area shows five seismic facies described as parallel, variable amplitude variable continuity, semi-continuous high amplitude, divergent variable amplitude and chaotic seismic facies as well as a probable shallow marine, deltaic and submarine fan depositional system. Linking lithofacies to seismic facies maps helped to understand and predict the distribution and quality of reservoir packages in the studied wells

This thesis describes experimental investigation of thermal and combustion phenomena as well as structure for self- propagating combustion synthesis of porous Ni - Ti intermetallic aimed for structural biomedical application. The control parameters for the porosity distribution have been investigated experimentally through varying the preheat temperature, initial porosity, initial elemental particle size, and applied pressure during the fabrication process. Ni and Ti elemental powders are mixed using a 1:1 ratio. The mixture is compressed using several different compression forces to produce cylindrical samples of 1.1 cm diameter and 2-3cm length, with initial porosity ranging from 30% to 40%. The samples are preheated to various initial temperatures and ignited from the top surface such that the flame propagates axially downwards. The combustion reaction is recorded with a motion camera. An infrared sensor is used to record the temperature profile during the combustion process. The samples are then cut using a diamond saw in both longitudinal and transverse directions. Image analysis software is then used to analyze the porosity distribution in each sample.
M.S.M.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering; Thermo-Fluids

Un premier objectif de cette thèseest de développer une méthodologie de mesurede perméabilité qui caractérise avec précision letenseur complet de perméabilité d'un tissu eninterlock en carbone utilisé dans la fabricationdes aubes de turbine d’avion par le procédé CRTM.Les caractéristiques uniques du tissu,notamment ses épaisseur et rigidité élevées,ses fibres opaques et sa double échelle deporosité très marquée, présentent des défis lorsde l'utilisation de techniques de mesuretraditionnelles.Afin de mesurer le tenseur complet deperméabilité de façon économique et sur uneplage étendue de fraction volumique de fibres,une combinaison de méthodes expérimentales aété proposée et utilisée.Les travaux portent également sur l’étude del'apparition de déformations du réseau fibreuxinduites par l'écoulement et propose une fenêtredeprocédé optimale pour imprégner les interlockslors du procédé C-RTM.Le développement d'un banc d'essaiexpérimental pour mesurer la saturationpendant l'injection est présenté, ainsi quel'influence de sa double échelle de porosité trèsmarquée. Les résultats sont complétés par unemodélisation numérique préliminaire à l’échellemésoscopique d'une géométrie simplifiéereprésentative.Les défis posés par la double échelle marquéede l’espace poral et les modes d’imprégnationdu tissu en interlock qui en découlent, justifientde l’approche proposée, combinant analyseexpérimentale et modélisation, qui doit êtrepoursuivie pour approfondir l’étude de cesmécanismes
A primary objective of this thesis is to developa permeability measurement methodology thataccurately characterizes the full permeabilitytensor of a carbon interlock fabric used in themanufacture of aircraft turbine blades using theC-RTM process. The unique characteristics ofthe fabric, including its high thickness andstiffness, its non-transparent fibers and itspronounced dual-porosity scale, presentchallenges when using traditional measurementtechniques.In order to measure the full permeability tensoreconomically and over a wide range of fibervolume fractions, a combination of experimentalmethods has been proposed and applied.The development of an experimental testbench to measure saturation during injectionand the influence of its very strong doubleporosity scale is presented. The results arecomplemented by preliminary mesoscopicnumerical modelling of a representativesimplified geometry.The challenges posed by the pronounceddouble scale of the pore space and the resultingmodes of impregnation of the interlocked fabricjustify the proposed approach of combiningexperimental analysis and modelling, whichmust be pursued in order to study thesemechanisms in greater depth

Three types of poly(norbornane carbonate) or PNC oligomers were synthesized and characterized via spectroscopic methods and elemental analyses to validate their chemical structures. Using the results from proton nuclear magnetic resonance (1H NMR) experiments, the degree of polymerization and size of each PNC chain was estimated via end-group analysis. All three types of PNC structures were both thermally-labile and acidolytically-labile, allowing them to be used as sacrificial materials in both direct-write and thermally-processed template systems. Thermogravimetric analysis (TGA) data was used to determine the kinetic parameters for the thermolytic decomposition reactions and evolved-gas analysis via mass spectrometry (TGA-MS) was used to determine the mechanisms for thermolytic degradation. PNC oligomers were freely-mixed with hydrogen silsesquioxane (HSQ) to form solutions that were spin-coated to form templated films. Transmission electron microscopy (TEM) showed that the free-mixing of PNCs with HSQ resulted in the agglomeration of the porogen molecules during the spincoating step. This phase-segregation produced domain sizes much larger than those of the individual chains, and during decomposition large pores were produced. To combat the phase segregation, hydrosilylation reactions were used to covalently bond vinyl end-capped PNC chains to silane-functionalized siloxane and silsesquioxane molecules. These matrix-like materials served as compatibilizers in order to improve the phase-compatibility of the sacrificial polymers in HSQ films. NMR and GPC analyses showed that the solids recovered from the hydrosilylation reactions were binary mixtures of hybrid nanocomposite molecules and residual ungrafted PNC chains. TEM imaging showed that the domains in these nanocomposite films had bimodal size distributions due to the presence of two components in the mixtures. The hybrid molecules produced pores ranging in size from about 6-13 nm as a result of improvements in the phase-compatibility of the grafted oligomers. However, the residual ungrafted oligomers in the blends produced larger domains measuring 30-40 nm. It is believed that separation difficulties can be avoided if the vinyl termination reaction conditions can be adjusted to ensure 100% conversion of all the terminal hydroxyl groups to vinyl groups. Doing so would allow all PNC chains to be grafted during hydrosilylation reaction; thus, avoiding the recovery of free PNC oligomers.

Nanomaterials have attracted substantial attention in the area of catalysis due to the unique properties they exhibit such as high surface areas, intricate pore networks and unique morphologies. TiO2 has attracted attention as a catalyst since the discovery of its high photocatalytic activity by Fuishima and Honda in 1972. Given its high thermal stability, low cost, low environmental impact, and versatility, TiO2 is a widely used commercial catalyst and catalyst support. TiO2 is used in many applications such as photocatalysis is also an excellent support material for noble metals in a number of oxidative synthesis and pollution-control reactions. Though TiO2 is a widely used catalyst support, currently available commercial titanias often have low surface area and poor thermal and hydrothermal stability. While several methods reported in literature produce materials of higher surface area and more ideal porosity relative to commercially available titanias, these procedures generally involve inherent drawbacks including time-consuming, complicated, and expensive processes that are not industrially viable. Cost-effective, large-scale preparations of stable, high surface area, mesoporous TiO2 need to be developed. The work in this dissertation focuses on (1) producing high surface area stabilized TiO2 supports of controlled pore diameters and (2) the preparation of well dispersed Pt on these supports using industrially viable processes. The effects of dopants Al, La, Si, and Zr on the stability, surface area, and porosity of anatase TiO2 supports were investigated. Results show that dopants increased the surface area and thermal stability of anatase through structural modifications and grain growth inhibition. Stabilized titanias produced by this method demonstrated equivalent or higher thermal stability and surface area compared with pure anatase and previously reported materials after treatment at 400°C and 700°C including 22 mol% Al-TiO2 calcined at 400°C which had a surface area of 479 ± 39 m2/g, a pore volume of 0.46 ± 0.04 cm3/g, and a pore diameter of 2.9 ± 0.2 nm. Ten synthesis variables were examined and optimized using statistically designed experiments (DOEs). Equations were developed to predict the conditions to obtain the highest surface area and pore volume at the desired pore diameter and predict the pore diameter range that may be obtained for aluminum-modified anatase TiO2. Confirmation trials closely matched predicted surface areas, pore volumes, and pore diameters in all but one trial, demonstrating the power of DOEs in identifying and controlling synthesis variables in relatively few experiments. The structure of Al-modified anatase TiO2 was analyzed to determine the mechanism of Al stabilization. Surface Al stabilized TiO2 by lowering anatase surface energy, stabilizing planes of high surface energy which would otherwise join to achieve stabilization. Al in TiO2 lattice vacancies stabilized TiO2 through increasing lattice strain and limiting mass transport necessary for grain growth. Results demonstrate the importance of structure analysis of doped nanomaterials in the development of stabilized catalysts and catalyst supports. An industrially viable, one-pot synthesis of Pt supported on 22 mol% Al-modified anatase is presented. Pt dispersions as high as 54% (one-pot method) and 59% (DI method) have been obtained. Results show that this one-pot method and the DI method using our Al-modified supports are promising syntheses of highly dispersed Pt catalysts and demonstrate that the alumina-stabilized anatase support is superior to other many available anatase supports.

L'objectif de cette thèse était de synthétiser des particules de carbonate de calcium (CaCO3) poreuses pour applications industrielles comme charge dans du papier à cigarette, ainsi que pour l'encapsulation d’'arômes. Nous avons cherché à maîtriser les paramètres de synthèse pour obtenir de la vatérite de taille contrôlée. Nous avons étudié sa transformation à haute température et dans l’'eau, car ce polymorphe est métastable. La transition de phase vatérite/calcite a été étudié par DRX et imagerie par diffraction des rayons X cohérents qui permet d’accéder à l’'image en 3D des particules. Nous avons montré que la vatérite de taille 1 à 2µm présentant 20% de porosité peut être synthétisée de façon reproductible. Les particules préparées ont été introduites comme charge dans du papier à cigarette pour évaluer l’'impact de nouvelles formes de CaCO3 sur les propriétés physiques du papier ainsi que sur la réduction des certains composées nocifs contenus dans la fumée. Nous avons développé l’analyse conjointe de l’'absorption et de la diffraction des rayons X pour estimer la charge réelle introduite ainsi que la porosité des papiers. Nous avons démontré que l’'utilisation de CaCO3 sous forme des sphères poreuses permet d’'augmenter la diffusivité du papier et de réduire l’'émission de CO dans la fumée principale.L’encapsulation d'arômes par la co-cristallisation et l'inclusion moléculaire dans le carbonate de calcium a été aussi étudiée. Nous avons montré que CaCO3 peut être utilisé comme matrice d’'imprégnation d'arômes avec une efficacité d’'encapsulation de plus que 55%. Les particules aromatiques ont été après ajoutées dans le papier pour évaluation sensorielle
The aim of this thesis was to synthesize porous calcium carbonate (CaCO3) particles for industrial applications as fillers for cigarette paper as well as a matrix for flavour encapsulation. We show that we can control the fabrication of porous particles of vaterite with a given size by tuning the parameters of synthesis. After the synthesis, the stability of vaterite in aqueous solution and at high temperature was studied. The phase transition was analyzed by XRD and coherent X-ray diffraction imaging that allows us to have a 3D-image of the particles. Finally, particles of 1-2 μm size with 20% porosity were reproducibly synthesized. Prepared vaterite particles were introduced as a filler in cigarette paper, with the goal to evaluate their impact on the physical properties of papers as well as on the reduction of some harmful compounds during the smoking. It was demonstrated that the use of vaterite can increase the diffusivity of paper and reduce the CO emission in the mainstream smoke. We also show that the use of X-ray absorption and diffraction can provide an estimation of the filler fraction and porosity of the papers in a non-destructive way. The encapsulation of flavours in CaCO3 particles was performed by co-crystallization and molecular inclusion. It was demonstrated that CaCO3 can be used as a matrix for flavour impregnation with more than 55% of encapsulation efficiency. Flavoured particles was added in paper for sensory evaluation. We shown that it is possible, to flavour the final product with flavoured calcium carbonate particles

La caractérisation et l’analyse des particules nano/micromètriques solides en suspension dans l’air ont récemment reçu une attention considérable. Le prélèvement représentatif des particules à analyser est une exigence fondamentale. L’échantillonneur d’aérosols récemment développé appelé Mini Particle Sampler (MPS), qui est équipé d’une grille poreuse de Transmission Electron Microscopy (TEM), rend l’échantillonnage de particules possible. Cependant, l’exploitation des résultats de ce système d’échantillonnage est encore à l’étape précoce. Cette thèse améliore et quantifie le système d’échantillonnage MPS. En outre, une nouvelle méthode de caractérisation de la masse de polluants est développée sur la base du système d’échantillonnage optimisé. L’efficacité d’échantillonnage des particules dont le diamètre de mobilité varie de 5à 100 nm est principalement étudiée. Selon l’analyse de sensibilité des paramètres dans l’ensemble de la configuration effectuée par la méthode Taguchi, la concentration en sel de l’atomiseur, la polarité à haute tension dans Differential Mobility Analyzer (DMA), la méthode d’évaluation de l’efficacité d’échantillonnage, la température d’échantillonnage, et la porosité de la grille TEM affectent le moins possible l’efficacité de collection. L apetite taille des pores du filtre, le débit élevé et les particules plus denses augmentent l’efficacité de collection des particules, qui sont les principaux paramètres. Basé sur l’étude des mécanismes de filtration des grilles TEM et la comparaison des modèles théoriques disponibles, une méthode d’analyse expérimentale de l’efficacité de collection combinée à la modélisation théorique est développée en considérant l’applicabilité du modèle. En utilisant cette méthode, les effets des principaux paramètres mentionnés ci-dessus sont comparés entre les expériences et les théories. La technologie d’échantillonnage est optimisée et l’efficacité minimale de collecte peut atteindre 40% en ajustant les paramètres du système d’échantillonnage. De plus, selon les méthodes de Monte-Carlo, les incertitudes sur l’efficacité de collection à partir des données mesurées et des modèles sont généralement inférieures à 1% et à 9%, respectivement. La plupart des données d’efficacité de collection mesurées sont couvertes par la plage d’incertitude d’efficience simulée par les modèles. L’analyse de sensibilité basée sur la variance de Sobol montre que la taille des pores et le débit de prélèvement contribuent de manière significative aux incertitudes et nécessitent un contrôle pour améliorer la précision de l’efficacité. En outre, le facteur de correction de Cunningham est également un paramètre de sensibilité. Sur la base du développement ci-dessus du système d’échantillonnage MPS, une méthode quantitative est proposée pour caractériser la concentration de masse élémentaire des particules micrométriques en suspension dans l’air par échantillonnage de particules etTEM - Energy Dispersive X-ray Spectroscopy (EDS). Le principe est de collecter les particules en suspension dans l’air sur une grille TEM, puis d’y ajouter une certaine masse de particules de référence, et de déterminer les pourcentages relatifs de tous les éléments (particules de référence et particules inconnues) via EDS. Indépendamment de la condition d’échantillonnage, la collecte quantitative et homogène des particules monodispersées RbCl, CsCl et NaCl sur la grille TEM a pu être réalisée. Pour toutes les conditions testées, lors du dépôt de divers types de particules en suspension quantifiées sur une grille TEM, les écarts absolus entre les pourcentages de masse des éléments théoriques et les rapports expérimentaux mesurés par EDS restent inférieurs à 10%, qui confirme que la méthode proposée pourrait être utilisée pour la caractérisation massique d’éléments dans un aérosol inconnu. Le RbCl a été préféré comme référence depuis sa rareté dans les particules aéroportées habituelles et sa faible toxicité
Characterization and analysis of airborne solid nano/micrometric particles have received considerable attention. The representative collection of particles to be analyzed is a fundamental requirement. The recently developed aerosol sampler called Mini Particle Sampler (MPS), which is equipped with a porous Transmission Electron Microscopy (TEM) grid, renders particle sampling convenient. However, the research for this useful sampling system is still in the initial stage. The thesis improves and quantifies the MPS sampling system. Besides, a new method of pollutant mass characterization is developed based on the optimizedsampling system. The sampling efficiency of the sampling system for particles with mobility diameters ranging from 5 to 100 nm is mainly investigated. According to the sensitivity analysis tof the parameters in the whole setup carried out by the Taguchi method, salt concentration of the atomizer, high-voltage polarity in the Differential Mobility Analyzer (DMA), sampling efficiency assessment method, sampling temperature, and porosity of the porous TEM gridminimally affect the collection efficiency. Small filter pore size, high flowrate, and denserparticles promote particle capturing, which are the main parameters. Based on the investigation of the filtration mechanisms of TEM grids and the comparison of available theoretical models, a method for experimental collection efficiency analysis combined with theoretical modeling is developed by considering the model’s applicability. Using this method, the effects of the main parameters mentioned above are compared between experiments andtheories. The sampling technology is optimized and the minimum collection efficiency isup to 40% by adjusting the parameter settings of the sampling system. In addition, accordingto the Monte-Carlo methods, sampling efficiency uncertainties from measured data andtheoretical models are generally less than 1% and 9%, respectively. Most sampling efficienciesmeasured data are covered by the efficiency uncertainty range simulated by models.Sobol variance-based sensitivity analysis shows that pore size and flowrate contribute significantly to the uncertainties, and require control to improve the efficiency precision. Besides, Cunningham correction factor is also a sensitivity parameter. Based on the above development of the MPS sampling system, a quantitative method is proposed to characterize the elemental mass concentration of airborne nano/micrometric particles via particle sampling and TEM - Energy Dispersive X-ray Spectroscopy (EDS). The principle is to collect airborne particles on a TEM grid, then add a certain mass of reference particles on it, and determine the relative percentages of all elements (reference and unknown particles) via EDS. Regardless of the sampling condition, the quantitative and homogeneously collection of monodisperse RbCl, CsCl, NaCl particles on the TEM grid could be achieved. For all the tested conditions, when depositing divers kinds of quantified airborne particles on one TEM grid, the absolute deviations between theoretical element mass percentages and experimental ratios measured by EDS remain lower than 10%, which confirms that the proposed method could be used for mass characterization of elements in an unknown aerosol. RbCl has been preferred as a reference since its rarity in usual airborne particles and having a low toxicity. The developed method has been used for characterizing aerosol released by the friction between serial pad and braking disc. The mass concentration of Fe in the braking aerosol is calculated as 0.105 μg/L using this method, which is consistent with the concentration range estimated from the data of Scanning Mobility Particle Sizer (SMPS) and Aerodynamic Particle Sizer (APS)

Biochar production processes as well as its various applications provide numerous benefits to both environment and economy (Lehmann et al., 2006; Basu, 2010). However, understanding the physicochemical structure of this valuable product has to be improved in order to be able to obtain the aforementioned benefits and to avoid environmental costs. In this study, chicken or poultry manure (PM) was chosen as feedstock for biochar preparation. This biomass is traditionally used by farmers as an effective organic fertilizer (Chan et al., 2008). Indeed, it is considered a valuable source for readily available plant nutrients, such as N, P, K and other micronutrients (Huang et al., 2011). Notwithstanding the advantages of PM for increasing soil fertility, there are food safety and environmental concerns about its application in agricultural sites in its unmodified form (Wilkinson et al., 2003; Chan et al., 2008). In fact, the misuse of chicken manure as fertilizer may result in serious environmental problems (Gay et al., 2003), such as human and animal health risks, odors, and leaching of nitrates 4 and other pollutants into groundwater (Fan et al., 2000). For this reason, conversion of chicken manure to char has been proposed as an attractive methodology to reduce PM volume and weight, and its stink (Shinogi and Kanri, 2003; Popov et al., 2004). Some studies have already examined PM biochar characteristics (Uchimiya et al., 2010). Further studies must be performed to evaluate the possibility to use poultry manure chars either as soil amendments or for remediation purposes in order to avoid environmental damages. As already stressed, char characteristics and properties are greatly affected by pyrolysis process and its parameters (mainly process temperature and residence time). These factors are particularly important in determining the nature of the final product and, consequently, its potential value in terms of carbon sequestration, agronomic performance and/or environmental remediation. The project has two main objectives. Firstly, it aims to report about the changes occurring in the chemical properties and in the physical structure of biochars produced from poultry manure when it is obtained at different pyrolysis temperatures and heating times, and how these changes can influence its agronomic or remediation potential. This topic is discussed in Chapters 3 and 4. The second objective of the project is to investigate the potential of three different kinds of biochars, produced from poultry manure, conifer and poplar wood residues, as adsorbents for inorganic contaminants (i.e., heavy metals) for wastewater treatment. In chapter 5, biochar adsorption qualities are evaluated using kinetic (pseudo-first order, pseudo-second-order), equilibrium and isotherms (Langmuir, Freundlich, Toth and RedlichPeterson) models, used to fit experimental data.

Prompted by increased interest in understanding microporosity, recent efforts at describing and classifying pore types in mudstones have focused primarily on siliceous, gas producing unconventional reservoirs with little attention being paid to carbonate, mixed oil-and-gas producers. The Niobrara Formation in the Denver-Julesburg Basin is a self-sourced resource play producing oil and natural gas from low permeability chalks. Key reservoir lithologies consist of chalk, chalky marl and marl. These lithologies contain flattened chalk fecal pellets which play a significant role in providing porosity. Integration of depositional fabric with pore-type distribution emphasizes the unique textural and depositional nature of chalk and provides a starting point for evaluation of diagenetic porosity modification. Chalk depositional textures comprise two main subdivisions. The first, called rainstone, includes chalks that form largely from settling of planktonic skeletal remains and fecal pellets as marine snow. New terms related to pelagic chalk textures are pelagic mudstone, pelagic wackestone, and pelagic packstone. The second, called allochthonous chalk, consists of chalks formed from syndepositional tectonic disruption of the seafloor, resulting in mass-movement and redeposition of chalk as turbidites and slide sheets. New terms related to allochthonous chalk textures are allomudstone, allofloatstone, and allorudstone. A chalk porosity classification consisting of four major pore types is presented that can be used to quantify Niobrara chalk pores and relate them to depositional texture, porosity networks, diagenetic history, and pore distributions. Interparticle porosity occurs largely between coccoliths and coccolith fragments, and decreases with burial ranging from 27-38% to 5-17%. Intraparticle porosity occurs within chalk pellets, coccospheres, coccolith plates and foraminifera tests, and also decreases with burial. Organic matter pores are intraparticle pores located within organic matter and are related to hydrocarbon generation. Channel pores, where present, can have significant influence on hydrocarbon storage and permeability networks. In the Niobrara, burial diagenesis in the form of mechanical compaction, chemical compaction, and syntaxial cement overgrowths, modifies pore shape and abundance. Porosity distribution is controlled by the abundance of chalk pellets and the mineralogy of the matrix. Permeability is a function of matrix lithology (micrite-rich vs. silt- and clay-rich). Understanding chalk depositional and diagenetic processes, and how they relate to porosity formation and pore evolution provide a foundation for more accurately predicting the occurrence and distribution of hydrocarbon source and reservoir rocks within the Niobrara.

The Late Cretaceous Trail Member of the Ericson Sandstone represents a regionally extensive fluvial system that transported sediments from the Sevier fold and thrust belt and Uinta Mountain uplift to the Western Interior Seaway. The Trail Member is a petroleum reservoir target that has unpredictable production rates due to the unknown behavior and connectivity of channel sandstones. The abundant outcrop, wellbore, and core data available allows for a comprehensive analysis of how the fluvial architecture, connectivity, and reservoir quality change along 65 km of depositional dip. Observations made at Flaming Gorge and Clay Basin (most landward field locations) suggest a highly mobile fluvial system that was influenced by both autogenic channel clustering and allogenic forcing. Evidence is seen for movement along the Sevier fold and thrust belt and early Laramide uplift of the Uinta Mountains. Specifically, three zones identify temporal tectonic changes throughout deposition of the Trail Member. The Upper and Lower Trail zones represent times of low accommodation as the fluvial system must avulse and move laterally to find available space. The Middle Trail zone represents a higher accommodation setting with internal autogenic channel clustering. This shows that on a finer timescale, autogenic processes control sediment distribution, while on a longer timescale, external drivers, specifically tectonics, control the distribution of sediment in the Trail fluvial system. Significant changes were observed within the Trail Member towards the basin. At Northern Colorado, lenticular, fluvial-dominated sands are still common, preserved organic and woody material, mud cracks, and increased bioturbation are observed that are not present elsewhere. The sandstone channels are slightly wider, have more common occurrences of low flow-regime sedimentary structures such as ripples and mud cracks, and appear to be more individually isolated with thin fine-grained material surrounding the channels. On a larger scale, photogrammetric analysis shows a rapid lateral change (0.3 km) from a sand-rich, channel-dominated expression to a mud-rich, channel-poor character. These observations suggest a lower energy fluvial system focused within a possible incised valley showing that the fluvial system is being influenced primarily by eustatic forces, rather than tectonics. Subsurface data from twelve wells located north of the Northern Colorado locality show a rapid (15 km) increase in thickness (97 m to 182 m) and decrease in net-to-gross (89.3% to 65.3%). Early subsidence of the Washakie sub-basin just east of the wells could account for the rapid increase in accommodation. Another possible explanation for the rapid thickness increase to the northeast could be the presence of an incised valley. These possibilities show the complexity of the environment within which the Trail Member fluvial system deposited sediments.

Metallic glasses exhibit many attractive attributes such as outstanding mechanical, magnetic, and chemical properties. Due to the absence of crystal defects, metallic glasses display remarkable mechanical properties including higher specific strength than crystalline alloys, high hardness and larger fracture resistance than ceramics. The technological breakthrough of metallic glasses, however, has been greatly hindered by the limited plastic strain to failure. Thus, several strategies have been employed to improve the intrinsic and extrinsic effects on the flow behavior of metallic glasses with respect to their fracture toughness and overall plastic strain. One of the suggested strategies is the production of a composite consisting of the brittle metallic glass along with a ductile second phase that either acts as an active carrier of plastic strain or passively enhances the multiplication of shear bands via shear-band splitting . Another approach for increasing plastic deformation consists of introducing pores as a gaseous second phase into the material. The pores are similarly effective in delaying catastrophic failure resulting from shear band localization. In metallic glasses with high porosity, propagation of shear bands can even become stable, enabling macroscopic compressive strains of more than 80 % without fracture. In this thesis, Ni59Zr20Ti16Si2Sn3 glass and its composites have been fabricated using mechanical milling and consolidation by hot pressing followed by extrusion of Ni59Zr20Ti16Si2Sn3 metallic glass powder or Ni59Zr20Ti16Si2Sn3 metallic glass powder reinforced with 40 vol.% of brass particles to obtained bulk composite materials with high strength and enhanced compressive plasticity and to generate porous structure in Ni59Zr20Ti16Si2Sn3 metallic glass using selective dissolution. The brass–glass powder mixtures to be consolidated were prepared using two different approaches: manual blending and ball milling to properly vary size and morphology of the second phase in the composites. Powder consolidation was carried out at temperatures within the supercooled Liquid (SCL) region, where the glassy phase displays a strong decrease of viscosity, with using the sintering parameters which were chosen after analysis of the crystallization behavior of the glassy phase to avoid its crystallization during consolidation. Ball milling has a significant effect on the microstructure of the powder mixtures: a refined layered structure consisting of alternating layer of glass and brass is formed as a result of the mechanical deformation. However, ball milling reduces the amorphous content of the composite powders due to mechanically induced crystallization and reaction of the glass and brass phases during heating. In addition, the milling of the composite powders and the following consolidation step reduces the amorphous content by about 50 %. The bulk amorphous Ni59Zr20Ti16Si2Sn3 alloy synthesized by hot pressing exhibits higher strength (2.28 GPa) than that of the as-cast bulk amorphous Ni59Zr20Ti16Si2Sn3 alloy (2.2 GPa). The mechanical behavior of the glass-brass composites is significantly affected by the control of the microstructure between the reinforcement and the nano-grained matrix phase through the different methods used for the preparation of the powder mixtures. The strength of the composites increases from 500 MPa for pure brass to 740 and 925 MPa for the composites with 40 and 60 vol.% glass reinforcement prepared by manual blending. The strength further increases to 1240 and 1640 MPa for the corresponding composites produced by ball milling caused by the remarkable effect of the matrix ligament size on the strengthening of the composites. The porous metallic glass was obtained by the selective dissolution in a HNO3 solution of the fugitive brass phase in the Ni59Zr20Ti16Si2Sn3 composite. The microstructure of the porous samples consists of highly elongated layered pore structures and/or irregularly shaped pores. The average size of the pores depends on the processing parameters and can be varied in the range of 0.4–15 µm. Additional porous samples were prepared from different extruded composite precursors of blended and milled powder mixtures. This leads to customized hybrid porous structures consisting of a combination of large and small pores. The specific surface area of the porous Ni-based metallic glass powder measured by the BET method is 16 m2/g, while the as-atomized Ni59Zr20Ti16Si2Sn3 powder has a specific surface area of 0.29 m2/g. This indicates a mechanical milling induced enhancement in surface area by refinement of the fugitive brass phase. However the specific surface area of the porous Ni-based metallic glass obtained from as-extruded precursors is 10 m2/g caused by a breakdown of the porous structure during selective dissolution of the nano-scale fugitive phase. Although milling of the present composite powders and the following consolidation step reduces the amorphous content by about 50 %, through the use of glassy phases with improved stability against mechanically induced crystallization along with reduced affinity with the fugitive phase to avoid unwanted reactions during processing, this approach using powder metallurgical offers the possibility to produce highly active porous bulk materials for functional applications, such as catalysis, which require the fast transport of reactants and products provided by the large pores along with high catalytic activity ensured by the large surface area characterizing the small pores. Accordingly, gas absorption ability tests of porous Ni-based metallic glass powders have been performed in order to evaluate the possibility of replacement of conventional support materials. From these first tests it can be conclude that additional opportunities should exist for nano-porous MGs with designed architecture of porous structures that are tailored to specific functional applications
Metallische Gläser weisen viele attraktive mechanische, magnetische und chemische Eigenschaften auf. Aufgrund der fehlenden Kristallstruktur zeigen metallische Gläser bemerkenswerte mechanische Eigenschaften, einschließlich höherer spezifischer Festigkeit, höherer Härte und größerer Bruchfestigkeit als Keramik. Der technologischen Durchbruch metallischer Gläser wird jedoch bis heute stark von ihremspröden Bruchverhalten behindert. Deshalb wurden verschiedene Herstellungsverfahren entwirkt, um sowohl die plastische Verformung der metallischer Massivgläser zu erhöhen, als auch um die mechanischen Eigenschaften generell zu verbessern. Eine mögliche Methode, zur Erhöhung der Plastizität und zur Beeinflussung der mechanischen Eigenschaften der metallischen Gläser ist der Einbau zweiter Phasen, wie z.B. durch Fremdpartikel Verstärkung oder Poren in Kompositen. Die Scherband bewegung wird durch die Wechselwirkung mit zweiten Phasen behindert, und gleichzeitig werden durch die in den Grenzflächen entstehenden Spannungsspitzen zwischen der zweiten Phase und der Matrix neue Scherbänder initiert. Dies führt zur Bildung einer Vielzahl von Scherbändern, was eine höhere plastische Dehnung zur Folge hat, da die Deformationsenergie auf ein größeres Volumen verteilt wird. In der vorliegenden Arbeit wurden Ni59Zr20Ti16Si2Sn3 Massivglas und mit Messing- verstärkte Komposite durch Kugelmahlen und Heißpressen mit anschließender Extrusion von Ni59Zr20Ti16Si2Sn3 Pulver oder Ni59Zr20Ti16Si2Sn3 Pulver mit 40 vol.% Messing Partikeln hergestellt. Neben der Herstellung der Ni59Zr20Ti16Si2Sn3 Komposite mit Messing Partikeln, wurden auch Ni59Zr20Ti16Si2Sn3 Komposite mit definierter Porösität durch die selektive Auflösung der zweiten Phase erzeugt. Die verwendete Mischung von Messing und metallischem Glaspulver wurde über zwei verschiedene Ansätzen hergestellt: die Pulver wurden manuell gemischt oder gemahlen, um die optimale Größe und Morphologie der zweiten Phase in den Komositen zu erzeugen. Das Sintern der Pulver erfolgte bei Temperaturen im Bereich der unterkühlten Schmelze, wobei die Legierung eine starke Abnahme der Viskosität zeigte, mit Hilfe optimierter Sinterparameter, die nach der Analyse des Kristallisationsverhaltens der gläsernen Phase ausgewählt wurden, um deren Kristallisation während der Konsolidierung zu vermeiden. Kugelmahlen hat einen signifikanten Einfluss auf die Mikrostruktur der gemahlenen Pulver: Eine verfeinerte Lamellare Struktur, teils bestehend aus Glas und teils aus Messing, wird durch mechanische Verformung gebildet. Kugelmahlen reduziert jedoch den amorphen Anteil der Komposite durch mechanische induzierte Kristallisation und die Reaktion der Glas- und Messing- Phasen durch Erwärmung. Das Kugelmahlen der Komposite (Pulver) und das darauf folgende Sintern führte zur eine Absenkung der freien Enthalpie der amorphen Phase um ca. 50%. Ni59Zr20Ti16Si2Sn3 metallische Massivgläser, welche durch Heißpressen hergestellt werden, weisen eine höhere Streckgrenze von 2.28 GPa als das gegossene Ni59Zr20Ti16Si2Sn3 Massivglas (2.2 GPa) auf. Die mechanischen Eigenschaften der mit Messing Ni59Zr20 Ti16Si2Sn3 verstärkten Komposite sind abhängig von der Kontrolle der Mikrostruktur zwischen den zweiten Phasen und der Matrixphase durch die verschiedenen Verfahren zur Herstellung von Pulvermischungen. Die Festigkeiten der Komposite, welche durch Handmischen und Heißpressen mit nachfolgender Extrusion hergestellt wurden, erhöhten sich von 500 MPa für reines Messing bis auf 740 und 925 MPa für die Komposite mit 40 und 60 Vol. % Glaspartikel- Verstärkung durch Handmischen. Die Festigkeiten erhöhten sich nochmals auf 1240 und 1640 MPa für die Komposite mit 40 und 60 Vol. % an Glaspartikel-Verstärkung mit lamellare Stuktur, die durch Kugelmahlen hergestellt würden. Die Ursache hier für liegt in der Wirkung der Ligamentabmessungen zwischen den Matrixbestandteilen hinsichtlich der Verfestigung der Komposite. Die Porösität im metallischen Glas wurde durch die selektive Auflösung der flüchtigen Messingphasen in den Kompositen mit Salpetersäure-Lösung erhalten. Die Mikrostuktur der porösen metallischen Gläser besteht aus stark elongiert geschichteten Porenstrukturen und/oder unregelmäßig geformten Poren. Die durchschnittliche Größe einer Pore hängt von den behandelnden Parametern ab und kann von 0.4–15 µm variieren. Weitere poröse Proben wurden ausgehend von verschiedenen extrudierten Komposit-Precursoren aus handgemischten und kugelgemahlenen Pulvermixturen erzeugt. Dies führte zu angepassten hybrid-porösen Strukturen bestehend aus einer Kombination von großen und kleinen Poren. Die spezifische Oberfläche des porösen Glaspulvers gemessen mit Hilfe der BET- Methode, beträgt 16m2/g, wohingegen das atomisierte Ni59Zr20Ti16Si2Sn3 MG Ausgangspulver eine spezifische Oberfläche von 0.29 m2/g besitzt. Dies weist darauf hin, dass das Mahlen eine Vergrößerung der Oberfläche durch die Verfeinerung der flüchtigen Messingphase induziert. Die spezifische Oberfläche der porösen-metallischen Gläser beträgt 10 m2/g und entsteht durch die Zerstörung der porösen Struktur während der selektiven Auflösung der nanoskaligen flüchtigen Phase. Obwohl das Kugelmahlen der Komposite (Pulver) und die darauf folgende Konsolidierung zwar den amorphen Anteil um etwa 50% reduziert, bietet die Pulvermetallurgische Herstellung durch die Verwendung von gläsernen Phasen mit verbesserter Stabilität gegenüber mechanisch induzierter Kristallisation, sowie einer reduzierten Affinität mit der flüchtigen Messingphase zur Vermeidung von unerwünschten Reaktionen während des Prozesses eine Möglichkeit, hochaktive poröse metallische Gläser für funktionelle Anwendungen, wie z.B. Katalyse, zu entwickeln. Hier ist eine schnelle Transport von Reaktanten und Produkten, welcher von den großen Poren, sowie eine hohe katalytische Aktivität, die von kleinen Poren und einer großen Oberfläche sichergestellt wird wesentlich. Daher wurden Untersuchungen zur Gasabsorptionsfähigkeit von porösem metallischen Glaspulver durchgeführt, um die Möglichkeit der Ersetzung von konventionellen Trägermaterialen bewerten zu können. Diese ersten Versuche zeigen die grundsäLzliche Eignung nano poröse metallischer Gläser zur Herstellung von porösen Strukturen mit einstellbarer Porenarchitektur auf die Langfristig für spezifische funktionelle Anwendungen von Interesse sein könnten

Metallic glasses exhibit many attractive attributes such as outstanding mechanical, magnetic, and chemical properties. Due to the absence of crystal defects, metallic glasses display remarkable mechanical properties including higher specific strength than crystalline alloys, high hardness and larger fracture resistance than ceramics. The technological breakthrough of metallic glasses, however, has been greatly hindered by the limited plastic strain to failure. Thus, several strategies have been employed to improve the intrinsic and extrinsic effects on the flow behavior of metallic glasses with respect to their fracture toughness and overall plastic strain. One of the suggested strategies is the production of a composite consisting of the brittle metallic glass along with a ductile second phase that either acts as an active carrier of plastic strain or passively enhances the multiplication of shear bands via shear-band splitting . Another approach for increasing plastic deformation consists of introducing pores as a gaseous second phase into the material. The pores are similarly effective in delaying catastrophic failure resulting from shear band localization. In metallic glasses with high porosity, propagation of shear bands can even become stable, enabling macroscopic compressive strains of more than 80 % without fracture. In this thesis, Ni59Zr20Ti16Si2Sn3 glass and its composites have been fabricated using mechanical milling and consolidation by hot pressing followed by extrusion of Ni59Zr20Ti16Si2Sn3 metallic glass powder or Ni59Zr20Ti16Si2Sn3 metallic glass powder reinforced with 40 vol.% of brass particles to obtained bulk composite materials with high strength and enhanced compressive plasticity and to generate porous structure in Ni59Zr20Ti16Si2Sn3 metallic glass using selective dissolution. The brass–glass powder mixtures to be consolidated were prepared using two different approaches: manual blending and ball milling to properly vary size and morphology of the second phase in the composites. Powder consolidation was carried out at temperatures within the supercooled Liquid (SCL) region, where the glassy phase displays a strong decrease of viscosity, with using the sintering parameters which were chosen after analysis of the crystallization behavior of the glassy phase to avoid its crystallization during consolidation. Ball milling has a significant effect on the microstructure of the powder mixtures: a refined layered structure consisting of alternating layer of glass and brass is formed as a result of the mechanical deformation. However, ball milling reduces the amorphous content of the composite powders due to mechanically induced crystallization and reaction of the glass and brass phases during heating. In addition, the milling of the composite powders and the following consolidation step reduces the amorphous content by about 50 %. The bulk amorphous Ni59Zr20Ti16Si2Sn3 alloy synthesized by hot pressing exhibits higher strength (2.28 GPa) than that of the as-cast bulk amorphous Ni59Zr20Ti16Si2Sn3 alloy (2.2 GPa). The mechanical behavior of the glass-brass composites is significantly affected by the control of the microstructure between the reinforcement and the nano-grained matrix phase through the different methods used for the preparation of the powder mixtures. The strength of the composites increases from 500 MPa for pure brass to 740 and 925 MPa for the composites with 40 and 60 vol.% glass reinforcement prepared by manual blending. The strength further increases to 1240 and 1640 MPa for the corresponding composites produced by ball milling caused by the remarkable effect of the matrix ligament size on the strengthening of the composites. The porous metallic glass was obtained by the selective dissolution in a HNO3 solution of the fugitive brass phase in the Ni59Zr20Ti16Si2Sn3 composite. The microstructure of the porous samples consists of highly elongated layered pore structures and/or irregularly shaped pores. The average size of the pores depends on the processing parameters and can be varied in the range of 0.4–15 µm. Additional porous samples were prepared from different extruded composite precursors of blended and milled powder mixtures. This leads to customized hybrid porous structures consisting of a combination of large and small pores. The specific surface area of the porous Ni-based metallic glass powder measured by the BET method is 16 m2/g, while the as-atomized Ni59Zr20Ti16Si2Sn3 powder has a specific surface area of 0.29 m2/g. This indicates a mechanical milling induced enhancement in surface area by refinement of the fugitive brass phase. However the specific surface area of the porous Ni-based metallic glass obtained from as-extruded precursors is 10 m2/g caused by a breakdown of the porous structure during selective dissolution of the nano-scale fugitive phase. Although milling of the present composite powders and the following consolidation step reduces the amorphous content by about 50 %, through the use of glassy phases with improved stability against mechanically induced crystallization along with reduced affinity with the fugitive phase to avoid unwanted reactions during processing, this approach using powder metallurgical offers the possibility to produce highly active porous bulk materials for functional applications, such as catalysis, which require the fast transport of reactants and products provided by the large pores along with high catalytic activity ensured by the large surface area characterizing the small pores. Accordingly, gas absorption ability tests of porous Ni-based metallic glass powders have been performed in order to evaluate the possibility of replacement of conventional support materials. From these first tests it can be conclude that additional opportunities should exist for nano-porous MGs with designed architecture of porous structures that are tailored to specific functional applications.
Metallische Gläser weisen viele attraktive mechanische, magnetische und chemische Eigenschaften auf. Aufgrund der fehlenden Kristallstruktur zeigen metallische Gläser bemerkenswerte mechanische Eigenschaften, einschließlich höherer spezifischer Festigkeit, höherer Härte und größerer Bruchfestigkeit als Keramik. Der technologischen Durchbruch metallischer Gläser wird jedoch bis heute stark von ihremspröden Bruchverhalten behindert. Deshalb wurden verschiedene Herstellungsverfahren entwirkt, um sowohl die plastische Verformung der metallischer Massivgläser zu erhöhen, als auch um die mechanischen Eigenschaften generell zu verbessern. Eine mögliche Methode, zur Erhöhung der Plastizität und zur Beeinflussung der mechanischen Eigenschaften der metallischen Gläser ist der Einbau zweiter Phasen, wie z.B. durch Fremdpartikel Verstärkung oder Poren in Kompositen. Die Scherband bewegung wird durch die Wechselwirkung mit zweiten Phasen behindert, und gleichzeitig werden durch die in den Grenzflächen entstehenden Spannungsspitzen zwischen der zweiten Phase und der Matrix neue Scherbänder initiert. Dies führt zur Bildung einer Vielzahl von Scherbändern, was eine höhere plastische Dehnung zur Folge hat, da die Deformationsenergie auf ein größeres Volumen verteilt wird. In der vorliegenden Arbeit wurden Ni59Zr20Ti16Si2Sn3 Massivglas und mit Messing- verstärkte Komposite durch Kugelmahlen und Heißpressen mit anschließender Extrusion von Ni59Zr20Ti16Si2Sn3 Pulver oder Ni59Zr20Ti16Si2Sn3 Pulver mit 40 vol.% Messing Partikeln hergestellt. Neben der Herstellung der Ni59Zr20Ti16Si2Sn3 Komposite mit Messing Partikeln, wurden auch Ni59Zr20Ti16Si2Sn3 Komposite mit definierter Porösität durch die selektive Auflösung der zweiten Phase erzeugt. Die verwendete Mischung von Messing und metallischem Glaspulver wurde über zwei verschiedene Ansätzen hergestellt: die Pulver wurden manuell gemischt oder gemahlen, um die optimale Größe und Morphologie der zweiten Phase in den Komositen zu erzeugen. Das Sintern der Pulver erfolgte bei Temperaturen im Bereich der unterkühlten Schmelze, wobei die Legierung eine starke Abnahme der Viskosität zeigte, mit Hilfe optimierter Sinterparameter, die nach der Analyse des Kristallisationsverhaltens der gläsernen Phase ausgewählt wurden, um deren Kristallisation während der Konsolidierung zu vermeiden. Kugelmahlen hat einen signifikanten Einfluss auf die Mikrostruktur der gemahlenen Pulver: Eine verfeinerte Lamellare Struktur, teils bestehend aus Glas und teils aus Messing, wird durch mechanische Verformung gebildet. Kugelmahlen reduziert jedoch den amorphen Anteil der Komposite durch mechanische induzierte Kristallisation und die Reaktion der Glas- und Messing- Phasen durch Erwärmung. Das Kugelmahlen der Komposite (Pulver) und das darauf folgende Sintern führte zur eine Absenkung der freien Enthalpie der amorphen Phase um ca. 50%. Ni59Zr20Ti16Si2Sn3 metallische Massivgläser, welche durch Heißpressen hergestellt werden, weisen eine höhere Streckgrenze von 2.28 GPa als das gegossene Ni59Zr20Ti16Si2Sn3 Massivglas (2.2 GPa) auf. Die mechanischen Eigenschaften der mit Messing Ni59Zr20 Ti16Si2Sn3 verstärkten Komposite sind abhängig von der Kontrolle der Mikrostruktur zwischen den zweiten Phasen und der Matrixphase durch die verschiedenen Verfahren zur Herstellung von Pulvermischungen. Die Festigkeiten der Komposite, welche durch Handmischen und Heißpressen mit nachfolgender Extrusion hergestellt wurden, erhöhten sich von 500 MPa für reines Messing bis auf 740 und 925 MPa für die Komposite mit 40 und 60 Vol. % Glaspartikel- Verstärkung durch Handmischen. Die Festigkeiten erhöhten sich nochmals auf 1240 und 1640 MPa für die Komposite mit 40 und 60 Vol. % an Glaspartikel-Verstärkung mit lamellare Stuktur, die durch Kugelmahlen hergestellt würden. Die Ursache hier für liegt in der Wirkung der Ligamentabmessungen zwischen den Matrixbestandteilen hinsichtlich der Verfestigung der Komposite. Die Porösität im metallischen Glas wurde durch die selektive Auflösung der flüchtigen Messingphasen in den Kompositen mit Salpetersäure-Lösung erhalten. Die Mikrostuktur der porösen metallischen Gläser besteht aus stark elongiert geschichteten Porenstrukturen und/oder unregelmäßig geformten Poren. Die durchschnittliche Größe einer Pore hängt von den behandelnden Parametern ab und kann von 0.4–15 µm variieren. Weitere poröse Proben wurden ausgehend von verschiedenen extrudierten Komposit-Precursoren aus handgemischten und kugelgemahlenen Pulvermixturen erzeugt. Dies führte zu angepassten hybrid-porösen Strukturen bestehend aus einer Kombination von großen und kleinen Poren. Die spezifische Oberfläche des porösen Glaspulvers gemessen mit Hilfe der BET- Methode, beträgt 16m2/g, wohingegen das atomisierte Ni59Zr20Ti16Si2Sn3 MG Ausgangspulver eine spezifische Oberfläche von 0.29 m2/g besitzt. Dies weist darauf hin, dass das Mahlen eine Vergrößerung der Oberfläche durch die Verfeinerung der flüchtigen Messingphase induziert. Die spezifische Oberfläche der porösen-metallischen Gläser beträgt 10 m2/g und entsteht durch die Zerstörung der porösen Struktur während der selektiven Auflösung der nanoskaligen flüchtigen Phase. Obwohl das Kugelmahlen der Komposite (Pulver) und die darauf folgende Konsolidierung zwar den amorphen Anteil um etwa 50% reduziert, bietet die Pulvermetallurgische Herstellung durch die Verwendung von gläsernen Phasen mit verbesserter Stabilität gegenüber mechanisch induzierter Kristallisation, sowie einer reduzierten Affinität mit der flüchtigen Messingphase zur Vermeidung von unerwünschten Reaktionen während des Prozesses eine Möglichkeit, hochaktive poröse metallische Gläser für funktionelle Anwendungen, wie z.B. Katalyse, zu entwickeln. Hier ist eine schnelle Transport von Reaktanten und Produkten, welcher von den großen Poren, sowie eine hohe katalytische Aktivität, die von kleinen Poren und einer großen Oberfläche sichergestellt wird wesentlich. Daher wurden Untersuchungen zur Gasabsorptionsfähigkeit von porösem metallischen Glaspulver durchgeführt, um die Möglichkeit der Ersetzung von konventionellen Trägermaterialen bewerten zu können. Diese ersten Versuche zeigen die grundsäLzliche Eignung nano poröse metallischer Gläser zur Herstellung von porösen Strukturen mit einstellbarer Porenarchitektur auf die Langfristig für spezifische funktionelle Anwendungen von Interesse sein könnten.

The quantitative estimation of reservoir properties directly from seismic data is a major goal of reservoir characterization. Integrated reservoir characterization makes use of different varieties of well and seismic data to construct detailed spatial estimates of petrophysical and fluid reservoir properties. The advantage of data integration is the generation of consistent and accurate reservoir models that can be used for reservoir optimization, management and development. This is particularly valuable in mature field settings where hydrocarbons are known to exist but their exact location, pay, lateral variations and other properties are poorly defined. Recent approaches of reservoir characterization make use of individual seismic attributes to estimate inter-well reservoir properties. However, these attributes share a considerable amount of information among them and can lead to spurious correlations. An alternative approach is to evaluate reservoir properties using multiple seismic attributes. This study reports the results of an investigation of the use of multivariate seismic attributes to predict lateral reservoir properties of gross thickness, net thickness, gross effective porosity, net-to-gross ratio and net reservoir porosity thickness product. This approach uses principal component analysis and principal factor analysis to transform eighteen relatively correlated original seismic attributes into a set of mutually orthogonal or independent PC??s and PF??s which are designated as multivariate seismic attributes. Data from the N-sand interval of Vermilion Block 50 field, Gulf of Mexico, was used in this study. Multivariate analyses produced eighteen PC??s and three PF??s grid maps. A collocated cokriging geostaistical technique was used to estimate the spatial distribution of reservoir properties of eighteen wells penetrating the N-sand interval. Reservoir property maps generated by using multivariate seismic attributes yield highly accurate predictions of reservoir properties when compared to predictions produced with original individual seismic attributes. To the contrary of the original seismic attribute results, predicted reservoir properties of the multivariate seismic attributes honor the lateral geological heterogeneities imbedded within seismic data and strongly maintain the proposed geological model of the N-sand interval. Results suggest that multivariate seismic attribute technique can be used to predict various reservoir properties and can be applied to a wide variety of geological and geophysical settings.

L’objectif de cette thèse porte sur le développement de nouveaux moyens de caractérisation mécanique de matériaux poreux inorganiques. La technique de microindentation instrumentée avec indenteur sphérique a été utilisée pour déterminer les propriétés mécaniques du plâtre pris, utilisé comme matériau modèle, à deux porosités différentes (30 et 60%vol). Les méthodes analytiques, développées initialement en nanoindentation, ont permis d’extraire la dureté et le module d’élasticité des deux matériaux, ainsi que les courbes contrainte-déformation d’indentation. Une méthodologie d’essai a été notamment détaillée afin de pouvoir appliquer cet essai d’indentation sphérique à l’étude de céramiques à forte porosité. Une approche numérique a permis de compléter les méthodes analytiques et d’identifier une loi de comportement élastoplastique pour le matériau modèle. Un modèle éléments finis 2D-axisymétrique a ainsi été développé pour simuler les essais d’indentation sphérique. Un module d’indentification inverse, MIC2M, a ensuite été utilisé pour identifier les paramètres associés au critère de Drücker-Prager (cohésion, frottement et dilatance) pour minimiser l’erreur entre la courbe expérimentale et numérique. La simulation de l’indentation Vickers, ainsi que des essais de compressions uniaxiaux et œdométriques ont permis de valider les paramètres matériaux identifiés par indentation sphérique. L’utilisation des techniques de tomographie aux rayons X et de microscopie électronique à balayage (MEB) a permis de mettre en évidence une densification du matériau au cours de l’indentation. Aucune fissure macroscopique fragile n’a par contre été observée, confirmant les différences de comportement mécanique entre des céramiques à fort taux de porosité et des céramiques denses. La méthodologie ainsi développée a ensuite été appliquée au cas d’une céramique biorésorbable à base de phosphate de calcium, famille de matériaux largement utilisée pour la substitution osseuse. Des cylindres de ciments brushitique ont subi un vieillissement in vitro d’une durée maximale de deux mois dans une solution de Phosphate Buffered Saline rafraichie. La méthode de microindentation a permis de suivre l’évolution des différents paramètres mécaniques au cours de la cinétique de dégradation des ciments. Les résultats ont montré une bonne corrélation entre les évolutions des propriétés mécaniques et physicochimiques des échantillons, suivies par diffraction des rayons X et MEB. Ainsi, après une dissolution initiale du ciment, la précipitation de nouvelles phases de phosphates de calcium plus stables a entraîné une augmentation des caractéristiques mécaniques en cours de vieillissement, mesurées par indentation. Cette méthode d’essai semble donc être un outil prometteur pour le suivi des propriétés d’explants biomédicaux et, plus généralement, des céramiques à fortes porosités
The objective of this study is to develop a methodology to characterize the mechanical behaviour of porous inorganic materials. Spherical instrumented indentation tests were used to determine the mechanical properties of a model material, gypsum, with two different porosities (30 and 60% vol.). Classical analytical methods, initially developed for nano-indentation, were used to extract the hardness and the elastic modulus of both materials, as well as stress-strain indentation curves. A methodology has been detailed in order to apply spherical indentation test to study high porous ceramics. To complete this analytical analysis, a numerical approach is used to identify an elastoplastic constitutive law for the material model. A 2D axisymmetric finite element model was developed to simulate spherical indentation tests. An inverse identification module, MIC2M, was then used to identify parameters associated to Drücker-Prager criterion (cohesion, friction and dilatancy) by minimizing the error between the experimental and the simulated indentation curves. These parameters were validated through the numerical simulation of a Vickers indentation test. Uniaxial compression and oedometer tests were also carried out on cylindrical samples to estimate the accuracy of the identified parameters. The mechanisms occurring during indentation were investigated using RX tomography and SEM. A large densified zone was noted below the indented area, with extensive gypsum crystal fracture. No macroscopic brittle crack could be observed confirming the differences between the mechanical behaviour of high porous ceramics and dense ceramics. The methodology developed in this study was applied to calcium phosphate cements, widely used for bone substitution. In-vitro degradation tests were performed on cylindrical samples of cements during 2 months into a refreshed Phosphate Buffered Saline solution. The micro-indentation method was enabled to follow mechanical properties of degraded samples and was discriminant enough to monitor the degradation process and its kinetics. Results showed a good correlation between evolutions of mechanical and physico-chemical properties of the cement investigated by X-ray diffraction and SEM. Thus, after initial cement dissolution, precipitation of more stable phosphate calcium phases implied an increase of the mechanical properties during aging. This method seems to be a promising tool for monitoring biomedical explants properties and, more generally, high porous ceramics

Obtention de rubans autosupportes ou supportes par differents substrats par projection plasma a partir de poudre de silicium. Optimisation du procede. Mesure des caracteristiques des rubans obtenus (porosite, densite, resistivite, mobilite de hall) avant et apres recuit, et apres recristallisation par bombardement electronique. Evolution des caracteristiques electriques avec le dopage. Mesure des proprietes photoelectroniques

Ce travail décrit la synthèse et la caractérisation physico-chimique de nanocomposites hybrides obtenus par imprégnation en voie liquide de bétâ-dicétonates d'Europium dans des silices mésoporeuses structurées aux tensio-actifs de type MCM-48 et MCM-41, post-fonctionnalisées ou non. La caractérisation des matériaux par ICP, spectroscopie électronique, diffraction des rayons X, thermogravimétrie, isothermes d'adsorption d'azote, RMN, spectroscopies UV-Vis et IR a permis de confirmer et de quantifier l'incorporation des complexes dans les pores de ces réseaux de silice. Les propriétés de photoluminescence de ces hybrides ont été également évaluées et les mécanismes gouvernant les interactions entre les parties organiques et inorganiques analysés dans le cadre de la théorie de Judd-Ofelt. Des conclusions sont avancées pour le design de systèmes hybrides hautement luminescents pour des températures d'usage de 60-70°C, généralement rédhibitoires pour les complexes organiques seuls

The thesis focuses on the characterization of the alteration of the mineral and organic phases, investigated with different approaches, of human bone tissue from different burial contexts, with ages spanning from the Late Roman period to our time. This topic is very important in paleontological, archaeo-anthropological and forensic contexts in order to understand the taphonomic agents and then to provide biological data as possibly to discern human behavior in ancient funerary as well as in recent forensic contexts. It is well-known that peri and post mortem events may leave marks that have to be interpreted in the light of the state of the conservation or degradation of the skeletal remains. In fact, physical anthropologists are frequently required to date human bone remains, in order to recognize if osteological samples have an archaeological, historic or forensic interest. The determination of post mortem interval (PMI), the time elapsed between the death and the discovery of the corpse or skeletal remains, is extremely difficult to evaluate in absence of direct chronometric dating (e.g. C14), since bones might undergo several alterations, both structural and chemical, depending on the environment in which they deposited in. Because of bone tissue is an intimate association of mineral (carbonate-hydroxyapatite) and organic components (collagen) arranged in an ordinary structure, different levels of degradation are possible. Over time post mortem degradation is dominated by loss of structural collagen by collagenolytic enzymes, which caused a rapid swelling and hydrolysis of the protein fibers. Collagen dissolution is generally accompanied by the alteration of mineral crystals, which are vulnerable to diagenetic changes due to their small size. During diagenesis, the protein can be totally or partially removed and can replaced by inorganic precipitates, the most common beign hydroxyapatite, which in the process is subjected to recrystallization, ion exchange and substitution. As consequence, when depositional conditions are favorable for bone preservation, the mineral crystallinity increase, the porosity and chemical composition change. The quality and the assessement of organic and inorganic phase, can act positively or negatively both on bone mechanical properties in live, both on decomposition process after death, reducing or accelerating it. Several studies were performed to better understand the taphonomy of bone material during burial time. It appears that bone degradation depends on a wide range of environmental interactions, including biological, chemical and physical factors. These include: average temperature and humidity, microbilological composition and activity, soil chemistry (mineralogy and pH) and permeability, mechanical pressure and other numerous factors. Different type of bone degradation are observable at different scale of observation; particularly, in this study, bone preservation was investigated at macroscopic, biomolecular, microscopic, ultramicroscopic and chemical scale. The aim of this research is thus to further describe the impact of environmental conditions on bone preservation, and the effect of time, by applying and comparing the results from different analitical techniques. For this study 40 human skeletons of adult individuals from four different dated burial location in the Milan area were analyzed. The first one is a necropolis dated to the Late Roman age (3th-4th century AD), the second one is a 17th century AD mass grave, the third one is an ossuary contanining bones dated between 15th and 18th century AD, and the last one is a modern cemetery. The macroscopic analysis evaluated the general appearance of the remains and their state of preservation, through the observation of specific macroscopic parameters and morphological characteristics. The Luminol test, a fast and inexpensive method developed to detect blood traces, was performed to investigate the presence of haemoglobin preserved in bone. The histological analysis, conducted on calcified thin sections, considered the presence or absence of tunneling and bioerosion, in accordance to the Oxford Histological Index (OHI). Also, to evaluate the state of preservation of the organic component, primarily collagen, the samples were decalcified and stained with Hematoxylin and Eosin. Because of the lack of literature in this field, we created a new Decalcified Histological Index (DHI). Both calcified and decalcified bone thin sections were observed in transmitted and polarized light microscopy, in order to test the optical properties of structural components. Scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) was used to evaluate exogenous chemical elements and minerals, adsorbed from burial environment, and histological changes, as well as recrystallization, tunnelling and fractures, due to fungal or bacteria action. X-ray micro-computed tomography of bone sections was performed at the SYRMEP beamline of the third-generation Synchrotron Light Laboratory (ELETTRA) located in Trieste (Italy), with the purpose to evaluate and quantify the preservation of bone structure, such as canals and lacunae, and the porosity changes due to diagenetic process. Fourier transform infrared spectrometry (FT-IR) and micro-spectrometry (mFTIR) were performed at Simon Fraser University (Burnaby) in Canada to investigate the preservation of both mineral and organic phases. Finally, 23 skeletons from the archaeological site of Travo (PC), dating from 7th-8th century AD, and their burial ground sediments were sampled and analyzed. Macroscopic, microscopic and chemical analyses were performed on bones to evaluate the tissue preservation state at different scales; the soil samples collected from the graves were characterized for color, particle size distribution, pH, organic carbon and calcium carbonate concentration. This study shows that macroscopic, biomolecular, microscopic, ultramicroscopic and chemical alterations follow independent paths that affect the bone preservation at different scales of observation. Therefore, the estimation of the diagenetic process cannot be limited to the macroscopic aspect of the bone tissue but must take into account biomolecular, microscopic and chemical alterations, since these may have affected the bone tissue differently at different scale. Bone degradation can be employed to estimate the post mortem interval, or to reconstruct the burial environment of human remains. As long as the evaluation of taphonomic alterations is performed at different scales with different ad hoc methodologies. In fact, age and environment can play an equal role on the degradation of organic and mineral phases, producing different effects on bone conservation at different levels.

Cette thèse présente une étude expérimentale pour améliorer le moulage par compression et transfert de résine thermoplastique (CRTM), axée sur l'efficacité industrielle, la durabilité et la recyclabilité, conformément aux objectifs de développement durable pour l’industrie, l’innovation et l’action climatique. En abordant la complexité de l'écoulement de la résine à plusieurs échelles dans le CRTM, cette recherche étudie l'écoulement transversal (à travers l’épaisseur) et la porosité induite par le processus à l'échelle méso des faisceaux de fibres de verre afin d'améliorer l'uniformité de l'imprégnation et le contrôle du compactage, en faisant le lien entre les cadres théoriques et les applications évolutives. L’étude est conduite sur une préforme, constituées de 6 couches de fibres de verre UD ([0/90]3) et d’une matrice thermoplastique en polypropylene (PP) mise en forme par un procédé CRTM . Un procédé « CRTM simplifié » permettant de contrôler la direction du front de matière est développé sur une presse industrielle, pilotée en déplacement. Trois configurations de procédé sont analysées : Configuration 1 (Référence) : configuration de type « film stacking » comme base de comparaison de la distribution de la résine et de la structure des fibres. Configuration 2 (CRTM simplifié) : Compression contrôlée par déplacement, les films de polymères formant initialement une couche unique en surface de la préforme. Configuration 3 (CRTM simplifié avec scellement des bords) : Compression améliorée avec un dispositif d’étanchéité limitant les fuites de résine en périphérie de la préforme et assurant un écoulement transversal. Un protocole d’analyse d'imagerie 2D est proposé, incluant l’analyse en lumière polarisée, la microscopie à fluorescence et la microscopie électronique à balayage pour caractériser qualitativement et quantitativement les taux de porosités au niveau des mèches et des plis de tissus. Un processus original de polissage en deux étapes permet de préserver l'intégrité de la surface. L'étude est complétée par une évaluation fine des mécanismes d'imprégnation à l'aide de la technique d'inspection hélicoïdale en microtomographie à rayon-X (micro-CT). Les résultats démontrent que les paramètres de compaction influencent directement le niveau d'imprégnation, atteignant une limite d'imprégnation. Cette thèse établit une démarche d’analyse du procédé CRTM pour des composites thermoplastiques haute performance, en vue d’une maitrise et d’une optimisation du procédé. Elle offre des perspectives sur des protocoles d’analyse précis basés sur l’étude à différentes échelles, améliorant la compréhension de l'interaction entre l'imprégnation et la perméabilité. Ces résultats répondent aux exigences de précision dans des secteurs tels que l'automobile et l'aérospatiale, où les composites CRTM sont essentiels pour les applications structurelles
This thesis presents an experimental study to advance thermoplastic Compression Resin Transfer Molding (CRTM), focusing on industrial efficiency, sustainability, and recyclability goals aligned with the Sustainable Development Goals for Industry, Innovation, and Climate Action. By addressing multi-scale resin flow complexity in CRTM, this research investigates transverse flow and process-induced porosity at the meso scale of glass fiber bundles to improve impregnation uniformity and compaction control, bridging theoretical frameworks with scalable applications. The study focuses on a thermoplastic polypropylene matrix reinforced with six layers of bidirectional UD woven glass fibers ([0/90]3) consolidated on a CRTM setup. The “Simplified CRTM” method is developed on an industrial press, using displacement-controlled compaction ratios. This method omits active resin injection, relying on a uniformly distributed viscous polymer pool beneath the unsaturated preform to drive resin flow uniformly with a unidirectional flow path. Controlled displacement and pressure optimize resin paths, manage fiber volume fraction, and reduce porosity. Three multi-step compaction configurations are evaluated: Configuration 1 (Reference): Uses force compaction as a baseline for comparing resin distribution and fiber structure. Configuration 2 (simplified CRTM): Displacement-controlled compaction enhances resin infiltration but faces challenges like edge race-tracking and fiber volume fraction (Vf) variability, affecting impregnation. Configuration 3 (simplified CRTM with Edge Sealing): Introduces high-temperature sealant tape at mold edges, limiting resin escape, maintaining transverse flow, and reducing porosity and race-tracking. Configuration 3 edge-sealing technique establishes a reproducible process for high quality CRTM composites. An advanced 2D multi-modal imaging protocol, tailored for partially impregnated samples produced via simplified CRTM with unfilled spaces and fragile microstructures, includes polarized light microscopy, fluorescence microscopy, and scanning electron microscopy for qualitative and quantitative characterization. An original two-step polishing process preserves surface integrity, and image post-processing workflows quantify impregnation quality and void distribution. The study is completed with a fine evaluation of the impregnation mechanisms using X-ray micro computed tomography technique (micro-CT) relying on helicoidal inspection method. Results demonstrate that compaction parameters directly impact impregnation level, reaching an impregnation limit. This thesis establishes a scalable, data-driven CRTM framework bridging laboratory experimentation with industrial requirements for high-performance thermoplastic composites. It offers insights into streamlined protocols and microstructure-based analysis, enhancing understanding of the interplay between impregnation and permeability in CRTM. These findings align with precision demands in sectors like automotive and aerospace, where CRTM composites are crucial for structural applications