VictorJuiz/thesis huggingface dataset:
Seismic modeling, inversion, and imaging in attenuating media [electronic resource]
Keywords: Geophysics.

Accurate seismic exploration demands sophisticated seismic techniques that can be applied to any complex geological setting, for example, attenuative and anisotropic media. This dissertation addresses attenuation problems in seismic exploration: how to model wave propagation in attenuating media, how to invert attenuation property of subsurface reliably, and how to mitigate attenuation effects in seismic images. The key innovations are (1) developing a novel viscoacoustic/elastic constant-Q wave equation that is practically efficient and accurately simulates the constant-Q attenuation behavior, (2) an iterative joint inversion framework for different geophysical datasets (e.g., attenuation data) to reduce the uncertainties of independent inversion results, (3) developing an Q-compensated reverse-time migration approach to compensate for attenuation effects (dispersion and amplitude loss) in seismic images. In the first part, I derive a novel viscoacoustic wave equation based on constant-Q theory. I investigate the accuracy of this wave equation. I show its application in a heterogeneous medium. Testing shows this model to be more computationally efficient than the most efficient single standard linear solid modeling. More importantly, this viscoacoustic equation separates attenuation and dispersion operators that allow us to mitigate both amplitude attenuation and phase dispersion effects in seismic imaging. This equation is the key modeling engine for seismic migration. Due to the data quality of the seismic waveform and the strong nonlinearity of the attenuation problem, I choose a joint inversion algorithm to invert for the attenuation coefficient. I develop an iterative joint inversion approach where one model domain acts as a constraint for inversion of the other, and the roles of the two domains are iteratively switched. This joint inversion stabilizes the inversion and ensures that results are geologically plausible. I apply the method to estimate Vp and the attenuation coefficient in field data examples. In the third part, I present a method to improve the image resolution by mitigating attenuation effects. I discuss the feasibility of time-reverse modeling in attenuating media using numerical experiments for 1D and 2D situations. I develop a Q-compensated reverse-time migration imaging approach (referred as Q-RTM). I illustrate this approach using different synthetic models. Numerical results further verify that this Q-RTM approach can effectively improve the resolution and quality of image, particularly beneath high-attenuation zones. To demonstrate the suitability, I apply the Q-RTM method to field data from the King Mountain site in west Texas. In the future, this method could readily be applied to other field datasets to improve the image resolution in high attenuation areas.
Seismic resilience of tall buildings - benchmarking performance and quantifying improvements [electronic resource]
Keywords: Civil and Environmental Engineering.

Modern tall buildings are generally not considered to be a large contributor to the seismic risk of cities, based on the presumption that they are designed and built with sufficient safeguards to ensure good performance. This is in spite of the fact that current building code provisions have few, if any, provisions to ensure that tall buildings have better performance than other low-rise structures. This implies that a 40-story building is not expected, or designed, to perform any better than a one-story building following a large seismic event, despite the huge differences in the consequences of collapse and/or damage to these type of structures. The performance of a 42-story couple core wall building located in downtown San Francisco, designed using a state-of-the-practice performance-based approach, is evaluated. Two additional structural schemes, damped outriggers and base isolation, and one additional non-structural scheme are investigated. Non-linear response history analysis is conducted on each of the three structural building designs in order to assess the structural performance at five different seismic hazard levels. Subsequently, the expected building repair cost and downtime are estimated for each scheme; there are six schemes in total when considering the additional non-structural design scheme. The baseline building is expected to suffer financial losses exceeding 15% of the total building cost and functional downtime of almost 2 years (84 weeks) following a design level earthquake. The damped outrigger and base isolation schemes are found to reduce financial losses and downtime, with an expected loss of 14% and 10% of the building cost, respectively and an expected functional downtime of 62 weeks and 43 weeks, respectively following a design-level earthquake. The non-structural design alternative, which also includes provisions to reduce building downtime, was found to reduce loss and downtime in all cases. The best performing building is the base-isolated building with enhanced non-structural design, expected to experience losses of 2.4% of the building value and functional downtime of only 6 weeks following a design-level earthquake. A cost-benefit analysis reveals that all schemes are preferable to the baseline building. The payback period for the two structural design alternatives is found to be 4.6 years and 6.6 years for the damped outrigger and the base isolation schemes, respectively, and the payback period for the non-structural design alternatives are 5.3 years, 9.0 years and 8.7 years for the fixed base, damped outrigger and the base isolation schemes, respectively.
Seismic risk assessment of complex transportation networks [electronic resource]
Keywords: Civil and Environmental Engineering.

This dissertation focuses on understanding seismic risk and possible mitigation measures for complex transportation networks. It first introduces frameworks and computationally-feasible strategies for assessing probabilistic risk to these transportation networks, and applies them to a case study of the San Francisco Bay Area. Using these strategies for a set of earthquake events, values of a network-performance measure called "mode-destination accessibility" are then calculated to link physical infrastructure damage with the impact on people's ability to travel to desirable destinations, one measure of post-earthquake human welfare. As a result, at-risk communities are also identified. The results suggest that accessibility varies greatly between communities across the case study region, whereas the differences across income groups are more subtle. Furthermore, increased walkability of a region correlates with lower expected losses in accessibility. Finally, this dissertation contributes an automated framework incorporating seismic risk and network importance into bridge retrofit prioritization. A key finding is that bridges important for the network functionality after an earthquake are not necessarily the weakest bridges nor the bridges with the highest pre-earthquake traffic volume. Instead, bridges at moderately high seismic risk on non-redundant routes play a particularly critical role.
Seismically enhanced light-frame residential structures [electronic resource]
Keywords: Civil and Environmental Engineering.

Seismic damage to buildings can be mitigated by enhancing the strength and stiffness of the lateral-force resisting system. Wood and cold-formed steel framed shear wall buildings present opportunities for implementing a strength- and stiffness-enhanced seismic design approach because these structures are relatively light, often include floor plans with plentiful wall areas, and are sensitive to damage at small levels of deformation. In light-frame construction, architectural finishes including gypsum wallboard partitions and stucco cladding can be particularly effective in increasing resistance to seismic loads if they are strengthened, stiffened, and integrated into the structural system. These enhancements can be achieved through the use of improved dowel-type fasteners and adhesives to connect sheathing and cladding to framing. This dissertation describes the development of strength- and stiffness-enhanced concepts for light-frame construction. A series of tests on enhanced light-frame components and walls confirmed that simple alterations to conventional walls can increase strength and stiffness several fold. Finite element wall models were developed to capture the behavior of enhanced light-frame walls and structures of varying geometry. A design approach for strength- and stiffness-enhanced light-frame structures that aims to drastically limit damaging building drifts during the design level earthquake is explained. For near-fault areas, parameters for a low-cost sliding isolation system to be used in conjunction with enhanced light-frame structures are recommended. A performance-based evaluation of strength- and stiffness-enhanced light-frame structures indicates that these buildings meet collapse safety targets under severe ground motions while reducing the probability of exceeding damaging seismic drifts by 60% to 80% when compared to conventional light-frame structures.
Sex Education: An Anti-Feminist Socialization of American Youth
Keywords:  Department of Anthropology
Sex education
young adults
narrative
gender socialization
Stanford University Department of Anthropology
Thesis

My research is on the ways in which young adults have come to learn about sex and
sexuality specifically through parent/guardian teachings and formal sex education.
Through my work, I analyze interviews conducted with 25 undergraduates at Stanford
University on their memories of sex education, using their narratives to complement
statistics that surround teen pregnancy and STI rates in the US. I engage with social
theory on socialization, female oppression, and the performance of gender, as well as
existing literature on sex education and the state of reproductive health. The aim of this
paper is to showcase the manner in which sex education plays a role in the perpetuation
of problematic gender socialization binaries through misleading sex education practices.
I demonstrate the benefit participant narratives can provide in illustrating more about
the human experience behind national reproductive health concerns, with the goal of
proposing nuanced approaches to such issues.
Shaping the past [electronic resource] : collective memory, history education, and student imaginations about World War II in contemporary Poland
Keywords: Education.

In this dissertation I attempt to move beyond traditional approaches to research about the teaching and learning of war and difficult history. My dissertation, Shaping the Past: Collective Memory, History Education, and Student Imaginations about World War II in Contemporary Poland, uses innovative research methods, analyzing seven textbooks, interviewing 60 teachers, and surveying nearly 176 students to examine how public debate and media influence what students know about wartime history. In the first part of this work I examine history textbooks published over the course of four decades. Textbook content has changed significantly over time, reflecting global trends in education, words are replaced with images, military heroes replaced with civilian ones, the books got shorter, and the Holocaust finally appeared as a historical topic after the year 2000. However, the World War II narrative within these books continued to privilege a Polonocentric version of the wartime past. Next, I examine teacher motivations to teach the Holocaust in Poland. I interviewed, sureveyed, and emailed a select group of educators who elected to teach the Holocaust in their K-12 classrooms. Unlike their Western counterparts, Polish teachers were not motivated by a desire to spread ideas about human rights or tolerance (as literature on Holocaust education suggests). What drove them was a desire to understand themselves, their family histories and their students, as well as to fill a gap in their personal history. In the second part of the dissertation I examine the relationship between young people's understanding of the country's troubled history and national presentations of the past. The analysis of 176 Polish student responses to iconic World War II era photographs, their written surveys, and essay narratives illuminate shared cultural narratives about war. Most students glossed over the complexity of the World War II wartime past, seemingly impervious to the influence of media and international attention to Polish-Jewish relations and the Holocaust. At the same time, analysis of student data unearthed dissonant responses from a small but important subset of students who demonstrated a recognition of the Holocaust and the Jewish-Polish experience. This recognition was in the form of budding "counter-narratives, " or interpretations that went against what is commonly believed in Polish society. Thus, in order to overturn previously accepted historical narratives about the difficult past, it may be necessary to introduce dissonance into the classroom that will build new knowledge. By analyzing Polish textbooks, teacher practice, and student understanding I sought to explore the role that collective memory, public debates and history play in education about a difficult and controversial past. My goal has been to use these findings to contribute to research on collective memory, and history education as well as to East European society and politics.
Silver nanowire transparent electrodes [electronic resource]
Keywords: Electrical Engineering.

Metal nanowire based transparent electrodes offer a lower cost, mechanically flexible alternative to industry standard transparent conductive oxides without making any optical or electrical performance tradeoffs. My PhD research has been focused on making high performance, fully solution processed transparent electrodes using meshes of randomly oriented, high aspect ratio silver nanowires (AgNWs). In this dissertation, I will cover several aspects of my work in this area. First, I will discuss the use of computer simulations to understand what has historically limited the performance of metal nanowire networks with an eye on understanding the changes that can be made during fabrication and post processing to address these performance limitations and increase overall transparent conductor performance. Secondly, I will cover the deposition and post-processing techniques I have developed to produce the highest performance solution processed transparent electrodes which reach a sheet resistance of 6.3 ohm/s while maintaining 92% visible light transmission, besting the performance metrics of the industry standard transparent conductor, ITO. I will cover the design and operating principals of a custom built deposition tool which uses silver nanowires having diameters 35-90nm and lengths 10-30µm to produce uniform, large area electrodes by a spray deposition method. I will also discuss the use of a laser annealing method to further increase the conductivity of these silver nanowire electrodes. Finally, I will discuss the integration of these high performance transparent conductors into several different types of optoelectronic devices. These devices include organic light emitting diodes with enhanced off-normal transmission, and a semi-transparent perovskite solar cell with 77% peak light transmission and 12.7% power conversion efficiency which is used as the top cell in a four terminal tandem architecture with a CIGS bottom cell giving an 18.6% tandem.
Simulating how humans hear themselves vocalize [electronic resource] : a two-parameter spectral model
Keywords: Music.

It is well known that people are often uncomfortable while hearing their recorded singing and speaking voice. This discomfort caused by the unfamiliarity with the recorded voice, compared to normal hearing, is due to a different transmission mechanism; listening to one's recorded voice only involves a single air-conduction pathway, whereas the voice we hear when we sing and speak propagates through both an air-conduction and a boneconduction pathway. Despite the well-known phenomenon, one's own hearing has received less attention among researchers since it is a very complex process involving multiple paths from vocal cords to hearing sensations. In addition, studying the auditory mechanism and perception of living humans adds more difficulty because of ethical concerns. In this dissertation, we conduct a perceptual experiment in order to investigate spectral characteristics of one's own hearing. Through this perceptual method, we expect to overcome the difficulties in the mechanical studies. Moreover, we develop a model of one's own hearing with two parameters based on the conclusive experimental result. This study is the first to propose a novel and simple model of own's own hearing and contribute many potential applications from medical devices to general consumer electronics. First, we design and implement an equalizer having eight frequency bands. Then, we conduct two experiments with different groups -- amateur singers and professional singers -- using speech and singing voice samples. During the experiment, subjects process their recorded voice by the equalizer, and determine the proximity of match to the imagined sung voice. We estimate transfer functions from air conduction to one's own hearing based on the chosen equalizer settings. In the result, we observe that the transfer functions intra-subject are relatively consistent and feature mostly band-pass filters. Moreover, the averaged transfer functions among subjects also present a relatively high degree of similarity regardless of gender and level of singing experience. The consistency of transfer functions allows us to develop a model. In the first simplification procedure, we run singular value decomposition (SVD) and calculate a lowdimensional approximation of the original data. Then, we derive three models from the reduced rank-2 matrix by further data simplification and filter alteration. After performing pilot tests with each model, we conclude that the third model, having one constant filter and two variable filters, can closely simulate one's own hearing with less effort. Lastly, we proceed the validation experiment and demonstrate the accuracy and usability of the model with positive feedback from participants.
Simulation of 3-D blood flow in the full systemic arterial tree and computational frameworks for efficient parameter estimation [electronic resource]
Keywords: Bioengineering.

Computational methods for simulating blood flow have become powerful tools to gain insight into the physical behavior of the cardiovascular system in health and disease. This work is aimed at developing computational tools and models for the investigation of age-related arterial stiffening and its relationship to the underlying hemodynamics. Due to the complex geometry and spatially-varying material properties of the central arteries, and the hemodynamics therein, large-scale three-dimensional computational models of arterial mechanics can improve our ability to interpret current clinical hemodynamic metrics and to advance our fundamental understanding of the mechanisms of disease progression. We have built a novel computational model of fully three-dimensional and unsteady hemodynamics within the primary large arteries in the human systemic circulation from head to legs. We demonstrated that this virtual full body systemic arterial tree is able to reproduce many of the key local and global hemodynamic features of the human arterial circulation and is a promising first step toward further computational analyses of the relationship between blood flow and arterial stiffening. As part of this work, we have tested and implemented an important boundary condition for the arterial fluid-solid interaction problem that mimics the tethering effect of the external tissues and stabilizes simulations in large networks of vessels. The task of efficiently fitting large-scale 3-D models to patient-specific measurements is challenging due to the computational effort required for a single simulation and the number of model parameters involved. We implemented two different computational frameworks for parameter estimation: the first is based on computationally inexpensive one-dimensional analogues of the full 3-D system. The second method is based on sequential data-assimilation techniques, specifically, nonlinear Kalman filtering. We demonstrate that these frameworks may be used to rapidly estimate the parameters of large-scale 3-D models based on clinical measurements of blood flow, pressure, and vessel wall distensibility.
Single-molecule studies of real protein synthesis [electronic resource]
Keywords: Structural Biology.

Translation, the last step in the process of cellular gene expression, is essential to life in all of its forms. At the center of translation is the ribosome, a multi-megadalton assembly of highly structured RNA and numerous proteins that together form a molecular-machine capable of both reading the genetic code and catalyzing the formation of the peptide bonds that connect the amino-acid building blocks of proteins. The ribosomal exit tunnel is the last point of interaction between the newly synthesized protein and the cellular gene-expression machinery and was for years thought to play only a passive role in the synthesis of protein, serving as nothing more than an inert conduit through which the peptide passes on its way into the cytosol. However, over the last several years an increasing body of evidence has suggested an active role for the tunnel in the control of expression of certain peptide sequences. Among these is SecM, a bacterial secretion monitor capable of stalling translation elongation on the prokaryotic ribosome in a co-factor independent manner. Extensive biochemical and cryo-EM structural studies have demonstrated that the SecM nascent chain stalls the ribosome by specifically interacting with the 50S subunit exit tunnel to inhibit peptide bond formation. However, how the SecM sequence changes translation dynamics prior to stalling and whether there are other necessary interactions with the ribosome not captured in the final stalled state, remains unclear. Using single-molecule fluorescence techniques combined with newly developed 'complete' in-vitro translation systems I monitored ribosome conformation and composition over the course of translation of a number of complex mRNA sequences. I demonstrate that the mechanism of SecM stalling involves a cascade of precisely timed peptide / tunnel interactions. In addition, the existence of a heretofore unknown family of E.coli stall sequences was conclusively demonstrated, and it was shown that some of the interactions involved in SecM-induced stalling contribute also to ribosomal stalling during translation of this new family of stall sequences. These results underscore the roles that the 50S subunit exit tunnel and nascent chain play in controlling translation and gene expression, while demonstrating the power and generality of single-molecule techniques to the discovery of previously unknown molecular phenomena and their mechanisms of action.
The sirin defense [electronic resource] [electronic resource] / : Berlin, Paris, and interwar Russian literature
Keywords: Slavic Languages and Literatures.

"The Sirin Defense: Berlin, Paris, and Interwar Russian Literature" presents several cross-sections of the Russian literary emigration between 1920 and 1940, focusing in particular on the work of Vladimir Nabokov and Vladislav Khodasevich. Close readings of novels, poetry, memoirs, and criticism are informed by an attention to the emerging cultural formations of interwar France and Germany, in particular cinema, urban surface culture, and professional chess. Particular prominence is given to the relationship between a writer's life and his art within the publishing context of the Russian emigration. The changing careers of Nabokov and Khodasevich are presented as self-conscious case studies in answer to the question, how does one become a writer in exile?.