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In my degree project I explore the importance of the void. Many people find emptiness terrifying, and feel like it has to be filled at any price. When everything has to be made more effective, and the dream of perpetual growth is considered the most beautiful one we have, emptiness becomes even more important.  My degree project explores what emptiness is and what it does to us. Furthermore, I examine my personal relationship with emptiness through illustration, as well as illustration through emptiness. It resulted in an illustrative essay about the void, and a booth where one can read it.

The raceway in the ironmaking blast furnace is a void in front of the hot blast tuyeres where coke and supplementary fuel burn to supply heat to the ironmaking process. The air velocity through the tuyeres is high (around 200 m/s) and this causes the coke particles to circulate in a rotating flow field inside the raceway. The size and shape of the raceway determine the gas flow dstribution, the reactions that occur, and the temperature profiles in the lower part of the blast furnace. It is for these reasons that the raceway has been extensively researched in the past. . Literature review revealed that forming and breaking of the raceway has not been yet studied. So, in the present study, we have concentrated our effort to study the formation and breaking of the raceway for different blast and bed parameters. The experiments have been performed in two-dimensional glass models. An attempt has been made to develop a correlation for each case. The formation of the void has been studied with change in parameters like density and size of the particles, bed height. The theory of the void formation has been derived from the fundamental principles. The formation of raceway, has been studied with the change in blast parameters like particle density and diameter, bed height and model width. It was found that when raceway is formed there is a sudden increment in pressure drop. The condition for breaking of the raceway, has been studied with change in blast and bed parameters like particle size and density, bed height and model width. It was observed that during the breaking of raceway, pressure decreases continuously. New semi-empirical correlations have been developed using dimensional analysis for formation of void, formation of raceway, and breaking of the raceway. The raceway growth also characterized with change in model width, flow rate, particle diameter, density of the particles and bed height. A few experimental results have been compared with published data. New semi-empirical correlation have been developed using dimensional analysis for the growth of raceway. Velocity of the gas exiting from top of the bed has been measured with the help of hot wire anemometer. It was observed that the velocity leaving from the bed is more on top of the raceway compared to the velocity leaving from the other parts of the bed. High velocity was observed near the wall of the model. Coefficient of wall-friction and angle of internal friction in presence and absence of gas were studied to explain the effect of bed height on formation of the void and raceway. It was observed that in presence of gas, coefficient of friction between the particles and wall and angle of internal friction between particles decreased, compared to the values in absence of gas. To study the effect of mixed particles, on the formation and breaking of the raceway, different sized particles in fixed proportion were taken. It was found that the experiments were more reproducible in case of uniform sized particles compared to mixed particles. It was also observed that for the same average particle diameter, mixture particles requires more velocity to form the void and raceway. New semi-empirical correlations have been developed using dimensional analysis for the formation of void, formation of raceway, growth of the raceway, and breaking of the raceway. Finally, an attempt has been made to quantify the various forces (pressure, bed weight & frictional forces) present in the raceway. Results show that further investigation is required in quantifying these forces properly.

A physically motivated Internal State Variable (ISV) constitutive model is extended to account for shear influenced void evolution for predicting damage behavior in ductile solids. The revised ISV model is calibrated for an aluminum 7085-T711 alloy using a series of microstructure and mechanical property quantification experiments. The calibrated ISV model for the aluminum alloy is implemented in an implicit finite-element code (Abaqus) to simulate the deformation of notch Bridgman tension specimens at a variety of stress states and temperatures. The model revisions and calibrated aluminum ISV model are validated through successful prediction of mechanical and microstructure evolution for structures subjected to a variety of complex stress state conditions. The extended ISV model framework is used to study shear influenced plasticity and damage mechanisms resulting from ballistic impact of metals. A Rolled Homogeneous Armor (RHA) steel alloy is selected for the impact model due to wide availability of documented penetration characteristics and ballistic performance data of RHA steel. Finite Element Analysis (FEA) simulations of ballistic impact of rolled homogeneous armor (RHA) steel projectiles against RHA steel plates are performed using a calibrated ISV constitutive model for RHA steel. An FEA simulation based parametric study is performed to assess the effect of a variety of microstructure and mechanical properties on the ballistic performance of RHA steel targets. FEA simulations are used to predict a transition in ballistic perforation mechanisms for high hardness steel alloys by accounting for variations in microstructure properties qualitatively documented in the literature.

Understanding the deformation mechanisms of soils and geosynthetics in response to the formation of a void below a geosynthetic-reinforced soil is crucial to provide efficient designs of geosynthetic-reinforced soil systems such as embankments and landfill liners. Centrifuge modelling of the soil and geosynthetic behaviour was conducted using a trapdoor to simulate the formation of a void in a controlled environment at realistic stress levels. A plane-strain model allowed visual observations of the deformation mechanisms using Particle Image Velocimetry. Granular soils and model clay liners were tested, as would be relevant to embankments and landfills respectively. These soils were tested with and without the reinforcement to evaluate the benefit provided by the geosynthetic. Detailed analysis of the centrifuge test results showed that arching significantly reduces the stress at the base of the soil when a void forms; this mechanism is due to stress redistributions and not the formation of a physical arch. A new method to reliably predict this reduction was provided by calculating the coefficient of lateral stress on the failure plane based on the observations of a continuous convex arc of major principal strains above the void, and the assumption that this is indicative of the stress behaviour. The observed results were also used to address the limitations in the current design methods related to the fill behaviour. Expansion in the soil was confined to a parabolic zone above the void estimated from the soil dilatancy, rather than a single, unique coefficient of expansion in the deforming soil. The zone of subsidence was characterised by the combination of a vertical prism and funnel to the surface, with the surface settlement profile better described by a Gaussian distribution rather than the parabolic profile used previously. An adaptation to the design methods for use with compacted clay liners was proposed by considering the clay as a beam with the maximum strain related to curvature and not elongation, and calculating the applied stress on the geosynthetic ignoring the clay arching. Analysis and interpretation of the centrifuge tests has thus given new insight into the soil and geosynthetic behaviour based on visual observations relevant to how these systems deform in practice. This has allowed the recommendation of more efficient design procedures and consequently will facilitate better predictions of geosynthetic-reinforced soil behaviour above voids.

The effect of electromigration on void formation and the failure mechanism of FCBGA packages under a current density of 1*104 A/cm2 and an environmental temperature of 150¢J was investigated. Eight solder/substrate combinations of four lead-free solder systems with two substrates were examined to verify the failure modes. A conservative failure criterion was adopted to define and predict the failure of the package. SEM was employed to observe in situ microstructural changes, IMC growth, and failure modes. All samples exhibited a similar failure, attributed mainly to void occupation along UBM/solder interfaces at the cathode chip side of the bumps with downward electron flow. Voids were initiated at the corner due to current crowding. Two specific void locations were identified at the IMC/solder and UBM/IMC interfaces, and they co-existed in the same specimen but in different bumps. No void coupling mode was found. Since the atom diffusion rate in the solder differs from that in the IMC layer, the voids can be formed between them. A current density of 1*104 A/cm2 was sufficiently high to form a void pattern at the IMC/solder interface. However, the formation of voids at the UBM/IMC interface is generally induced by the consumption of UBM, since the high temperature of 150¢J crucially dominates the void morphology at the UBM/IMC interface. The difference among solder systems did not affect the failure modes nor dominate mechanisms. Two theoretical models based on the experimental results were applied to describe the void formations. They will be more accurate and useful in understanding void formations by further experimental data provided. According to the results of solder bumps with electrons only flowed through Al trace line at die side, it suggested that atoms transport toward the bottom substrate along with the temperature gradient and toward the right corners along with electron flow when electrons flowed through the trace after the resistances of solder joints reaching 120¢H of their initial values. With respect to the differences of substrate surface finishes, more voids appeared at the cathode substrate side of the solders combined with Cu/Ni/Au pad than those combined with Cu-OSP after long-term upward electron stressing. It suggested another possible failure at the substrate side when failure did not occur at the chip side in an EM test.

The Westinghouse FRIGG loop in Västerås, Sweden, has been used to study the distribution of steam in the coolant flow of nuclear fuel elements, which is known as the void distribution. For this purpose, electrically heated mock-ups of a quarter BWR fuel bundles in the SVEA-96 geometry were studied by means of gamma tomography in the late 1990s. Several test campaigns were conducted, with good results, but not all the collected data was evaluated at the time. In this work, tomographic raw data of SVEA-96 geometry is evaluated using two different tomographic reconstruction methods, an algebraic (iterative) method and filtered back-projection. Reference objects of known composition (liquid water) are used to quantify the decrease in attenuation arising from the presence of the void, which is used to create a map of the void in the horizontal cross sections of the fuel at various axial locations. The resulting detailed void distributions are averaged over subchannels and the subchannel steam core for comparison with simulations. The focus of this work is on the void distribution at high axial locations in the fuel, in fuel bundles with part-length fuel-rods. Measurements in the region above the part-length rods are compared with simulations and the reliability of each method is discussed. The algebraic method is found to be more reliable than the filtered back-projection method for this setup. A reasonable agreement between measurements and predictions is shown. The void, in both cases, appears to be slightly lower in the corner downstream the part-length rods.

A collection of four original short stories written by Utah State University student Kevin Larsen. These fictional stories were written with particular attention to the magical realism and horror genres in an attempt to combine both the fantastic and the horrific. In addition to these stories, this thesis contains a literature review of both contemporary and historic authors including, but not limited to, Brian Evenson, Bret Easton Ellis, David Lawrence Morse, and Kelly Link.

Two-phase flows with or without phase change are present in terrestrial and space applications like thermal control of satellites, propellant supply for launchers, and waste water treatment for space exploration missions. Flow boiling experiment with HFE7000 were conducted in a heated tube in vertical upward flow on ground and in microgravity conditions to collect data on flow patterns, pressure drops, heat transfers, void fraction. Void fraction measurements allowed to measure mean gas velocity and the liquid film thickness in annular flow. In microgravity condition, the liquid film thickness and the interfacial shear stress are significantly lower than in normal gravity. A detail analysis of the film structure was performed by image processing. The impact of gravity and liquid and vapour superficial velocities on the disturbance waves velocities and frequencies was investigated. Two different measurement techniques were used and compared to determine the heat transfer coefficient. For quality values greater than 0.2, HTC is not sensitive to gravity and is in good agreement with classical correlations of the literature. For qualities smaller than 0.1, in the subcooled nucleate boiling regime HTC is significantly smaller in microgravityconditions.

Un contrat dont les conditions de formation ne sont pas remplies est nul. Ce poncif du droit des obligations mérite aujourd’hui d’être nuancé. Aux côtés des sanctions traditionnellement enseignées se développent des techniques tendant à remédier à l’invalidité. La première partie de la thèse est consacrée à l’étude du développement de ces remèdes et de leurs manifestations. L’émergence des remèdes à l’invalidité contractuelle, tardive, a été justifiée par les avantages procurés par le maintien du contrat malformé. Le XXe siècle a fait preuve d’audace en la matière avec l’apparition de techniques extrêmement variées qui peuvent être mises en œuvre par les parties ou par le juge. Ce panorama effectué, un constat est possible : la multiplication progressive et casuistique de ces techniques nouvelles a pour conséquence néfaste un véritable éclatement de la matière. Afin de pallier cet éclatement, la seconde partie de la thèse s’attache à bâtir un système nouveau. Une notion unique, associé à un régime harmonisé, peut ainsi être construite autour du dénominateur commun de l’ensemble des techniques correctives. En définitive, la théorie de la validation du contrat serait le pendant utile et nécessaire de la théorie de l’invalidation. Elle offrirait un droit de correction du contrat invalide face au droit de critique dégagé depuis maintenant près un siècle. / When the requirements for the formation of a contract are not met, that contract is void or voidable. This longstanding principle of contract law should now be reconsidered. Alongside traditional contractual remedies, new curatives mechanisms have been developed to preserve the validity of contracts that would historically be deemed invalid. The first part of this paper describes the development of these cures and outlines how they are implemented. The recent emergence of these new contractual cures is a function of the advantages of preserving the validity of contracts that would otherwise be invalidated. The 20th century has witnessed the development of a great variety of bold new mechanisms which can be implemented either by the judge or by the parties themselves. This paper will make clear that the gradual and casuistical accretion of novel cures has led to a dramatically fragmented set of rules. To adress this situation, the second part of this paper recommends the development of a new system around a notion and a unified legal regim, both derived from the common denominator of the existing contractual cures. The theory of contractual validation would eventually be the necessary and useful counterpart of the theory of invalidation. It would complement the right to challenge invalid contracts that was elaborated almost a century ago with a right of correction.