Sedimentary rock-hosted deposits are a major source of copper and cobalt, with the Neoproterozoic central African Copperbelt being among the largest Cu-Co provinces in the world, accounting for around 15% of its copper resource. The deposits occur primarily in the carbonates and siliciclastic sediments overlying the basement, and formed during early diagenesis (around 820 Ma) and late diagenesis/metamorphism during the Pan-African Orogeny (580-520 Ma). The northwest province of Zambia hosts three major copper deposits, amongst which is Kansanshi: the focus of this study. The deposit, which lies north of the Solwezi dome, is hosted within the Katangan Supergroup, particularly within the carbonaceous phyllites and porphyroblastic schists of the Mshwaya subgroup and lower Nguba Group and extends along the strike length of the North-West trending Kansanshi antiform. In this study, tomographic inversion is applied to first arrival refraction data collected at the Kansanshi Copper Mine with the aim of locating potential copper-bearing structures.  The survey was carried out using both dynamite and VIBSIST sources along 3 profiles; 2 trending North-East across the Kansanshi anticline and 1 trending north-west parallel to it. Seismic refraction tomography is an excellent tool for investigating the shallow subsurface, providing a velocity distribution. Unlike conventional refraction seismics, it allows for the velocity calculation of each cell in a non-homogeneous earth model, rather than just the average velocity of individual layers - allowing us to map structure and infer geological units and weathering profiles. The data highlights abundant faulting and varying depth to fresh bedrock. The various lithologies have also been interpreted.

Propagation of a Gaussian beam in a layered periodic structure is studied analytically, numerically, and experimentally. It is demonstrated that for a special set of parameters the acoustic beam propagates without diffraction spreading. This propagation is also accompanied by negative refraction of the direction of phase velocity of the Bloch wave. In the study of two-dimensional viscous phononic crystals with asymmetrical solid inclusions, it was discovered that acoustic transmission is nonreciprocal. The effect of nonreciprocity in a static viscous environment is due to broken PT symmetry of the system as a whole. The difference in transmission is caused by the asymmetrical transmission and dissipation. The asymmetrical transmission is caused solely by broken mirror symmetry and could appear even in a lossless system. Asymmetrical dissipation of sound is a time-irreversible phenomenon that arises only if both energy dissipation and broken parity symmetry are present in the system. The numerical results for both types of phononic crystals were verified experimentally. Proposed devices could be exploited as collimation, rectification, and isolation acoustic devices.

Quelle que soit la nature des ondes utilisées et des milieux traversés, le contrôle de la propagation ondes est d'un intérêt majeur pour de nombreuses applications. D'une part, la complexité du milieu peut être exploitée en exerçant un contrôle cohérent du front d’onde incident. D'autre part, on peut forcer une onde à se propager suivant un chemin désiré en concevant soi-même le milieu de propagation. Dans cette thèse, nous étudions ces deux aspects à partir d'expériences ultrasons-laser mettant en jeu la propagation d'ondes de Lamb dans des plaques.La propagation des ondes à travers un milieu diffusant est tout d’abord étudiée à partir de sa matrice de diffusion. Une prédiction théorique importante est l’existence de canaux de propagation totalement ouverts ou fermés. Une première partie de ces travaux consiste à démontrer expérimentalement ce résultat en mettant en évidence la possibilité de transmettre totalement une onde à travers un milieu désordonné. Dans un second temps, la mesure d’une matrice des temps de vol nous permet d’étudier ces canaux dans le domaine temporel. Ceux-ci donnent lieu à des paquets d’onde dont la cohérence spatiale et temporelle est conservée tout au long de leur propagation dans le milieu.Le second volet de cette thèse consiste à tirer profit des phénomènes de réflexion et réfraction négative afin de contrôler la propagation des ondes de Lamb. D’une part, la réflexion négative est mise à profit pour réaliser une conjugaison de phase passive des ondes de Lamb. D’autre part, le concept des milieux complémentaires est exploré afin d’annuler la diffraction des ondes et ainsi camoufler certaines zones du milieu de propagation. / Whatever their nature or the propagation medium, controlling the propagation of waves is of fundamental interest for many applications. On the one hand, one can tame wave-fields in order to take advantage of the complexity of the medium. On the other hand, one can force waves along desired paths through a careful design of manmade materials. In this thesis, we study those two aspects on the basis of laser-ultrasonic experiments involving the propagation of Lamb waves in elastic plates.The control of wave propagation through complex systems is first investigated by means of the scattering matrix approach. In diffusive media, theorists have demonstrated the existence of propagation channels either closed or open through which the wave can travel. The first part of this work present a direct experimental evidence of this result as well as the ability to fully transmit a wave through a disordered medium. In a second part, the measurement of the time-delay matrix allows the study of such channels in the time domain. They are shown to give rise to particle-like wave packets that remain focused in time and space throughout their trajectory in the medium.The second part of this thesis consists in studying the concepts of negative reflection and refraction for the manipulation of Lamb wave propagation. On the one hand, negative reflection is taken advantage of to perform a passive phase conjugation of Lamb waves. On the other hand, the notion of complementary media is investigated in order to cancel the diffraction of waves and cloak some areas of the plate.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第21910号 / 情博第693号 / 新制||情||119(附属図書館) / 京都大学大学院情報学研究科知能情報学専攻 / (主査)講師 延原 章平, 教授 西野 恒, 准教授 飯山 将晃 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

In this thesis, I expand considerations of diaspora as not only a migration of people and cultures but a migration of thought. Specifically, I demonstrate that literary representations of diaspora produce what I consider to be an epistemological migration, challenging the idea that race and culture are stable and impermeable and offering instead racial and cultural fluidity. I assert that this causal relationship is best exemplified by narratives of racial passing written by diasporic writers. Using Homi Bhabha’s concepts of mimicry, hybridity, and ambivalence, I analyze Helen Oyeyemi’s Boy, Snow, Bird and Zoë Wicomb’s Playing in the Light, arguing that Boy, Snow, Bird’s narrative form is a form of mimicry that repeats European and African literary traditions and subverts Eurocentrism, while Playing in the Light is a “Third Space” in which to accept notions of the non-categorical fluidity of race. Through this analysis, I draw particular attention to Oyeyemi’s and Wicomb’s unique abilities to refract notions of race, rather than presumably reflect a system of strict categories, and, ultimately, I argue that these novels transcend the realm of literature, existing as empowering calls for society’s modifications of its racial perceptions.

In a society where people are always making plans and running in-between places, uncontrollable scenarios, such as rain, can be read as mere obstacles to the much acclaimed ‘routine’. With a strong appreciation for unexpected events, I instead want to propose a solution to make people approach rain in a more curious way, building for it a celebrative setting. A path of analysis, research, and experimental testing led to the design of a possible transformation of a rainwater harvesting system into a lighting installation. Considering the current climate change conditions, and the severe drought situations in some areas, rain has to be interpreted today not just as a poetic phenomenon, but also as a necessary and primary resource.  In TOTEN, daylight and artificial light are combined in a dynamic storyline, with the goal to emphasize the presence or the lack of rain and to make people gain insight about the rainfall trend. While an optical illusion and colors are asked to achieve a communicative and attractive condition, the structure wants to be clean and easily affordable. Reminiscent of a totemic sculpture, TOTEN appears, in the results, as a symbolic place where light and water use their liquid shapes to tell stories.

Reflectivity images of the lower crust and uppermost mantle beneath the Illinois basin have been derived from reprocessing of several hundred kilometers of industry seismic reflection data using extended vibroseis recorrelation. The recorrelation was based on extending an originally 4-s correlated record, acquired with a 16-s sweep from 14 to 126 Hz, to the absolute limit of the full 20 s (~70 km) listening travel time. The reconstructed bandwidth includes frequency components suitable for imaging structures from signals received from both sedimentary basin reflectors and those received from reflectors in the deep crust and upper mantle. Mantle and sub-Moho reflectors are imaged down to 18 s two-way travel time (~62 km) and are observed on intersecting profiles generally dipping to the southwest and striking northwest-southeast. Occasional Moho reflections are also observed across the profiles (~12 s or ~38 km) while reflectivity in the lower crust is generally marked by intermittent horizontal packages and short, gently dipping reflections and diffraction segments. The presence of newly observed mantle reflectivity beneath the Illinois basin indicates significant upper mantle heterogeneity, relative to other parts of the USA studied using reflection methods. The relatively isolated occurrence of mantle reflections beneath the basin makes it difficult to uniquely infer their origin. However, available geologic and geophysical constraints, especially from geochemical and geochronological studies of drilled basement rocks, effectively limit the possibilities to: (1) remnants or "scars" of sub-crustal processes associated with lithospheric extension or delamination related to the melting of the Proterozoic crust that led to the emplacement of the granite--rhyolite province that underlies much of USA Midcontinent; or (2) deformation caused by plate subduction associated with the hypothetical accretion of a juvenile arc to the pre-1.6 Ga southern margin of the Laurentian continent.

A Look to Burst the Brightest Neon Hearts is an inquiry, via constellation of stories diffuse in structure and subject matter, into the various (and really weird) phenomena comprising contemporary American existence. Cumulatively, the stories seek to: (1) kick up, like bottom feeders searching biogenous sediment, an underlying value system, and (2) explore how language both breastfeeds and like, weans this value system-e.g., what dark matter is it that tethers bromances to reality TV? Quantum mechanics to pop music? How can a country be responsible for both the world's highest incarceration rates, and OKCupid? These stories also explore various American conceptions and embodiments of love, plotting out a strange attractor of cultural reflection and refraction.

Traffic noise has been shown to have negative effects on exposed persons in the communities along highways. Noise from transportation systems is considered a nuisance in the U.S. and the government agencies require a determination of noise impacts for federally funded projects. There are several models available for assessing noise levels impacts. These models vary from simple charts to computer design models. Some computer models, i.e. Standard Method In Noise Analysis (STAMINA), the Traffic Noise Model (TNM) and the UCF Community Noise Model (CNM), have been used to predict geometric spreading, atmospheric absorption, diffraction, and ground impedance. However, they have largely neglected the atmospheric effects on noise propagation in their algorithms. The purpose of this research was to better understand and predict the meteorological effects on traffic noise propagation though measurements and comparison to acoustic theory. It should be noted that this represents an approach to incorporate refraction algorithms affecting outdoor noise propagation that must also work with algorithms for geometric spreading, ground effects, diffraction, and turbulence. The new empirical model for predicting atmospheric refraction shows that wind direction is a significant parameter and should be included in future modeling for atmospheric refraction. To accomplish this, the model includes a "wind shear" and "lapse rate" terms instead of wind speed and temperature as previously needed for input of the most used models. The model is an attempt to explain atmospheric refraction by including the parameters of wind direction, wind shear, and lapse rate that directly affect atmospheric refraction.

The increasing prevalence of myopia over the past few decades and its association with potential ocular complications make myopia an important research topic. The present work is concerned with the structural and functional characteristics of a group of myopic and emmetropic individuals. The technical experiments in this work investigated firstly the effect of instrument alignment on peripheral refraction measurements and revealed that the corneal vertex was an acceptable alignment position of the Shin-Nippon NVision-K 5001 autorefractor, allowing consistent alignment with other instruments used in this research. Secondly, spectacles could be used to provide comparable vision to contact lenses in the visual performance studies. In the main experimental parts of this work, visual performance and multiple aspects of ocular structure were assessed across a wide range of eccentricities along the horizontal and vertical meridians within the same eyes. The structural properties of the myopic eye were measured through central and peripheral autorefraction, and through cornea to retina dimensions using non-contact biometry. In addition, the central and peripheral resolution acuities of myopic and emmetropic eyes for high and low contrast levels were investigated. Our structural and functional measurements revealed relatively prolate myopic eyes with reduced high contrast resolution acuity, compared to emmetropic eyes. Moreover, multiple regression analyses were performed at the fovea and outermost retinal eccentricities common to all core experiments but revealed no strong relationship between the structure and function of the myopic eye. Finally, regarding asymmetry, the nasal and superior retinae were found to be longer and to perform better in comparison to the temporal and superior retinae respectively.