VictorJuiz/thesis huggingface dataset:
Characterizing hydrologic and economic risk due to flooding driven by atmospheric rivers
Keywords: Engineering.

Atmospheric rivers (ARs), sometimes called "rivers in the sky," are long, narrow bands in the atmosphere that carry high levels of moisture from the tropics to the mid-latitudes. They deliver up to half of California's annual water supply, but they also can cause extreme precipitation and floods. The overall goal of this dissertation is to identify which ARs are most likely to cause damaging flooding. First, I connect AR hazard, which is based only on the intensity of the atmospheric event, to AR risk, which includes the exposure and vulnerability of infrastructure and communities. Using tools from earthquake engineering, probabilistic risk analysis, and interpretable machine learning, I characterize AR-driven flood risk from both a process-based (top-down) and a data-driven (bottom-up) perspective. These two complementary approaches are used to identify influential drivers of extreme consequences. I then quantify the contribution of temporal compounding to the hydrologic and economic impacts of ARs. Temporal compounding is the risk amplification that occurs when two or more AR storms occur in close succession. The series of ARs that affected California in the early months of 2023 are an example of the significant consequences that temporal compounding can cause when the hydrologic environment does not have time to recover between events. I create a new metric, AR sequences, to identify when temporal compounding is contributing to risk. I show that sequences are associated with higher levels of hydrologic impacts, such as extreme runoff and soil moisture, than ARs are on their own. They also increase both the probability and the magnitude of economic impacts from damaging flooding. Finally, sequences are expected to increase in frequency, intensity, and duration in a future climate, with the largest frequency increases occurring at the longest durations. Altogether, this dissertation both identifies a growing threat to California's water resources and introduces a suite of AR flood risk assessment tools to manage that threat.
Charging ahead or leaving behind? Climate change, air pollution and environmental justice consequences of vehicle electrification in India
Keywords: Sustainability.
Energy Resources Engineering.

India, with a population projected to reach 1.64 billion by 2050 and responsible for approximately 7% of all greenhouse gas (GHG) emissions, faces significant challenges in achieving environmental sustainability in its transportation system. Vehicle electrification has been proposed as a potential solution, but the net effects on GHG and criteria air pollutant emissions are influenced by the electricity generation mix, carbon capture and air pollution control technologies used. In this dissertation, we perform a state-specific life-cycle assessment to evaluate GHG and sulfur dioxide (SO2) emissions for representative passenger vehicles and technologies. Results show that battery electric vehicles (BEVs) have higher GHG and SO2 emissions in most states under present conditions, indicating that widespread vehicle electrification is not feasible until the grid decreases CO2 and SO2 emissions. We also model the change in PM2.5 exposure, premature mortality and monetized damages from multiple vehicle electrification and grid scenarios, finding that vehicle electrification under present day conditions increases premature deaths from air pollution. Higher PM2.5 exposure levels are seen in scheduled castes/tribes, poor, and rural populations compared to urban and high-income groups, particularly in high coal production states. Switching to zero-emitting electricity generation sources such as renewables, nuclear or installing technologies such as post combustion carbon capture and storage (CCS) and flue gas desulfurization units would reduce premature mortality from road transportation due to air pollution. We also find that enabling CCS in coal power plants in India could reduce power sector GHG emissions by 743 million metric tons per annum along with air pollution related health co-benefits
Chemical ecology of alkaloids in poison frogs
Keywords: Humanities and Sciences.
Biology.

Alkaloids are used as chemical defenses by taxa spanning the tree of life, including plants, insects, birds, fish, and amphibians. Poison frogs of the family Dendrobatidae sequester alkaloids from their diet of small arthropods and use these alkaloids, in tandem with their aposematic coloration, to deter predation. Poison frog toxicity has been studied for decades, with much of the work focusing on characterizing the diversity of toxins found across species. This foundational work has enabled the pursuit of additional questions looking at how these alkaloids shape the interactions of frogs with other organisms in their environments. In this dissertation work, I use a combination of natural sampling in the field, controlled laboratory experiments, and detailed in vitro and molecular analyses to explore the role of alkaloids in poison frog ecology and evolution. First, I explore the relative impact of genetics and the environment in shaping poison frog alkaloid profiles and find that poison frogs seem to be locally adapted to environmentally available alkaloids, such that frogs are better able to sequester, and in some cases modify, alkaloids to which they have been historically exposed. Then, I examine the impact of alkaloids on the skin microbiome of poison frogs and find that alkaloids play a significant role in shaping the microbiome, making microbial communities more diverse and less even. These patterns seem to be explained, at least in part, by the ability of some strains to metabolize alkaloids for use as a carbon source. Together, these findings expand upon our understanding of how alkaloids shape poison frog ecological interactions across scales ranging from the microscopic to the evolutionary.
Chen Renyu’s Junpu: An Annotated Translation with Discussion on China’s Earliest Edible Mushroom Manual
Keywords:  Stanford Global Studies
Junpu
Ethnomycology
History of Science
Chen Renyu
Translation
Song Dynasty
China
Mushrooms
Fungi
East Asia
Text
Thesis

Though not widely acknowledged in the present era, the Junpu《菌譜》(“Materia Mycologica”, 1245), also known as the Xiangxunpu 《香蕈譜》(“Manual of Fragrant Fungi”), is a historical Chinese mycological monograph authored in the late Southern Song (1127-1279) by scholar-official Chen Renyu 陳仁玉 (b. 1212), significant for its dual status as not only the earliest manual of edible mushrooms recorded from China, but also indeed the oldest practical treatise on fungi known from anywhere in the world. Despite the considerable limitations of the Junpu in terms of its actual informational scope – comprising fewer than nine hundred characters in total, with contents featuring only a brief synoptic preface followed by summary descriptions for a small number of mushrooms found from the author’s native county, and entirely devoid of illustrations – Chen Renyu’s pioneering work on fungi is nevertheless notable for having achieved a remarkable degree of influence on the subsequent development of more comprehenesive mycological literatures both in China and elsewhere in East Asia.
Thus, with the primary goal of establishing greater awareness of Chen Renyu’s Junpu as China’s archetypal mycological monograph, this thesis first proceeds with a brief biography on the life and activities of Chen Renyu, followed by a select overview of the complex contents of his original work, thereby presenting a conceptual basis for interpreting the text itself. The next section of the paper then presents readers with a new comprehensive English-language translation of the entire Junpu treatise. This translation is supplemented by extensive annotations providing commentary on the material covered therein, with particular attention being given to possible identites of the mushrooms featured in the work as well as the numerous linkages between pre-Song Chinese ethnomycological records and contemporary Song mushroom culture revealed by its contents. Following the annotated translation, the third section of the thesis engages in a brief discussion on the textual history of the Junpu and its considerable influence on later Chinese and Japanese mycological monographs. Finally, the paper concludes with an assessment of the Junpu’s unique significance to the overlapping fields of Chinese, East Asian, and global ethnomycological research, as well as a brief closing statement regarding its relevance both to present-day mushroom cultures around the world and to the future trajectory of human relations with fungi at a universal level.
China’s Economic Statecraft in Cross-Strait Relations: A Case Study of Outbound Tourism and Agricultural/Fishery Trade
Keywords:  Stanford Global Studies
Stanford Global Studies
East Asian Studies
economic statecraft
cross-strait relations
Text
Thesis

This thesis aims to analyze and evaluate Beijing’s use of economic statecraft in cross-strait relations through case studies of outbound tourism and preferential treatment for agricultural/fishery trade. China’s economic inducement and coercion in outbound tourism and agricultural trade concessions were unsuccessful, but the contract farming program of milkfish in Syuejia was somewhat successful. This thesis draws the following conclusion about factors determining the effectiveness of China’s economic statecraft. The lack of compatibility of goals between state and commercial actors, especially intermediaries’ maximization of their own economic profit, posed implementation challenges to the Chinese state. The direct communication between targeted people and mainlanders could work both positively and negatively. In the coercion phase, efforts by the target to diversify its market helped mitigate the economic damage of coercive measures.
Chrisitianizing harmonies : the transformation of sound in late antiquity
Keywords: Humanities and Sciences.
Religious Studies.

In the early fourth century CE, the Roman emperor Constantine embraced Christianity and initiated the Christianization of the Roman Empire. In this revolution, old institutions lost power, while new social, political, and religious forces emerged. This dissertation explores one major aspect of this revolution that has not appeared in scholarly narratives about the transformation of the Roman Empire in late antiquity: sound. It argues that the Christianization of pagan sound was a central feature of the Constantinian revolution. To convert the Empire to Christianity, Christians sought to transform the soundscape, or acoustic environment, from the realm of pagan gods into a vast cathedral resonating with harmonies for Christ. In other words, perceiving the non-Christian world as out of calibration like a poorly tuned instrument, Christians endeavored to retune the world from dissonant and demonic paganism into a Christian consonance that would govern the new Christian Empire. Taking many forms, these harmonizing efforts produced a multivocal soundscape that consisted of psalm singing, shouting, silencing demonic outbursts, and even belching. In sum, late antiquity hosted a polyphonous chorus of Christian voices all participating in the great harmonizing work of Jesus as they Christianized the soundscape of the world
Circuit quantum acoustodynamics with a fluxonium qubit
Keywords: Humanities and Sciences.
Applied Physics.

Quantum information is fragile, and the physical systems we use to protect it are often complex. Even with rapid advances in superconducting circuits over the past two decades, this leading platform for quantum engineering utilizes substantial electronic and spatial resources per qubit. This inspires a search for hardware-efficient strategies to build on the success of superconducting circuits. One such strategy involves the integration of mechanical resonators, offering smaller spatial footprints, sensitive detection of mass or force, and prospects for long energy-relaxation lifetimes. Coupling rates between circuits and mechanics are enhanced by the use of strongly piezoelectric materials, extending the reach of circuit quantum electrodynamics into the domain of mechanical systems. In this thesis I describe efforts to achieve strong coupling between a superconducting qubit and a piezoelectric mechanical resonator with frequency below 1 GHz. The main result is a device achieving phonon-number-resolving readout of a 690 MHz mechanical resonator. Phonon-number resolution was first observed using few-GHz nanomechanical resonators coupled to a transmon qubit at a similar frequency, leveraging strong piezoelectricity in thin-film lithium niobate. I show that integrating a lithium niobate mechanical resonator with a fluxonium qubit can access lower mechanical frequencies while preserving strong coupling and control capabilities at the single-phonon level. I describe initial attempts to measure coherence times of a phonon at 690 MHz, argue that these attempts were limited by thermal effects, and suggest cooling protocols to control thermal effects in future work. I conclude by discussing future experiments in strongly-coupled quantum acoustics, some of which may be enabled with near-term improvements in the fluxonium-mechanical system
Climate Change Leads to Relative Decrease in Coarse Woody Debris Volume in West Coast US Forests
Keywords: climate change
forests
Coarse woody debris
Machine learning
model
Forest Inventory and Analysis Program (U.S.)
Text
Article
Thesis

The impact of climate change on dead wood volumes in US forests remains uncertain. Coarse woody debris, or pieces of dead wood at least 3 inches in diameter, play an especially important role in habitat quality, wildfire risk, and carbon storage. This study leverages machine learning techniques and data from the US Forest Service’s Forest Inventory and Analysis Program to predict coarse woody debris volumes in California, Oregon, and Washington under different climate change scenarios. Our results suggest that though coarse woody debris volumes are predicted to increase due to increasing stand age, climate change has a relatively negative impact on CWD volume. We posit that this could be driven by increased decomposition. This study represents the first machine learning approach to predicting the volume of coarse woody debris under climate change and adds to a small but growing body of evidence that climate change will have a negative impact on CWD volume.
Climate crucible : American choices in Germany, Japan, and the making of the Great Acceleration, 1939-1953
Keywords: Humanities and Sciences.
History.

This dissertation presents a new interpretation of American responsibility and reveals overlooked contingencies in the acceleration of key drivers of anthropogenic climate change in the mid-twentieth century. Historians have recognized links between the ascent of the United States to superpower status in the 1940s and the launching of the Great Acceleration--a global skyrocketing of greenhouse gas emissions and resource consumption starting soon after 1945. Scholarship has focused largely on longer-term climate effects of American actions and domestic consumption. Less attention has been paid to another form of American contribution: choices by U.S. foreign policymakers as they shaped transnational patterns of industrialization and resource use across a pivotal decade for global politics and environmental change. More fully understanding the making of the Great Acceleration requires investigating the degree of choice and knowledge of risk among U.S. policymakers from the late 1930s to the early 1950s. Engaging U.S. military, diplomatic, and intelligence archives, this dissertation investigates how American policymakers developed ideas that stressed equality over competition in postwar industrial geography and resource use in Europe and Asia--and why they ultimately discarded these ideas. Each chapter focuses where competing choices and risks appeared sharply: debates regarding Germany and Japan during war and occupation. While U.S. policymakers did not understand the climate impacts of their choices, they knowingly turned from plans that supported more balanced and sustainable transnational patterns of industrialization and resource use in Europe and Asia to accept risks of global inequality, resource exhaustion, and preparation for future world war. This work bridges historiographies of the American empire, U.S. foreign relations, and critical Anthropocene studies to expand historical insights on the deepening climate crisis
Cloud services and the performance of small firms
Keywords: Cloud computing
Small business
Text
Thesis

Do cloud services boost small firms’ performance? Cloud services change a risky, fixed- cost investment in IT services to a variable-cost purchase of only IT services that have been used. As a result, cloud service providers like Google, Microsoft, and Amazon often advertise their products to small firms. However, cloud service has their own drawbacks for firms, such as the possibility of high costs due to unexpected high usage and changing prices by cloud service providers. This paper aims to answer whether the usage of cloud services improves the financial performance of small firms. Previous papers have limited their analysis to manufacturing plants, or have only been able to use survey or proxy data. In this paper, I use data from querying the website of small firms directly to find out whether they are using a cloud service technology as part of their IT infrastructure. This more direct dataset standardizes what is meant by a “cloud service” and focuses analysis on the impact of infrastructure cloud services, as opposed to the diverse array of cloud services more generally. Using a dataset of firms’ Amazon Web Service (AWS) usage and financial performance from 2000 and 2018, I run a difference-in-difference model to find the effect of using AWS on small firms’ revenue compared to larger firms’. I found that there is significant evidence that adopting AWS improves small firms’ revenue by as much as 60%, while adopting AWS appears to actually have a negative impact of large firms’ revenue.
Clustering approaches for faster nonlinear projection-based model order reduction
Keywords: Aeronautics and Astronautics.

Projection-based model order reduction is a technology for dramatically reducing the cost of expensive computational physics simulations by approximately solving the governing equations in a data-driven approximation subspace. This dissertation proposes a set of techniques that exploit the concepts of locality and clustering to further accelerate reduced-order models on challenging problems. The first exploits the fact that many physical systems exhibit spatially localized features such as shocks or wakes to construct space-local reduced-order models that are more efficient than existing model-reduction schemes. The second takes advantage of locality in the simulation's state-space to construct smaller bases composed of a few nearby solution snapshots. Both novel techniques proposed here are applied to multiple systems drawn from computational fluid dynamics, including a challenging large-scale turbulent flow problem. In all applications, multiple orders of magnitude of speedup are observed relative to the original high-dimensional computational model, and substantial speedups are also observed relative to previously-existing model-order reduction techniques
CMOS-compatible strain engineering and device scaling of monolayer molybdenum disulfide transistors
Keywords: Engineering.
Electrical Engineering.

Moore's Law has been the driving factor behind the exponential growth of the semiconductor industry over the past six decades. As the reduction of silicon features approaches the atomic limit, we are once again at an inflection point, requiring researchers to investigate new ultrathin semiconductors to overcome these limitations. Monolayer transition metal dichalcogenides (TMDs) are a class of atomically-thin materials which have demonstrated promise for nano-scaled transistors owing to their excellent electrical properties in this regime. In silicon technology, the first great advance beyond conventional scaling came from harnessing strain to improve performance. Strain is also known to affect the band gap of TMDs but has rarely been investigated in TMD transistors on rigid substrates. In the first part of this thesis, I explore how electron beam evaporation, the most commonly used technique for contact formation to TMDs, can introduce significant tensile strain to monolayer molybdenum disulfide (MoS2). Next, I demonstrate a fully industry-compatible approach to impart strain to two-dimensional TMD transistors using tensile-stressed silicon nitride capping layers. I apply it to both back and dual-gated devices, demonstrating improvements up to 60% in the on-state current of monolayer MoS2 transistors. The next major advance in silicon technology came from the introduction of high-κ /metal gate technology, offering improved gate control. In the final part of this thesis, I developed a process which allows the integration of monolayer MoS2 on thin, high-κ dielectrics which enables lower voltage operation, improved subthreshold behavior and drive currents up to ~700 μA/μm at a channel length of 50 nm. Together, these results offer a holistic approach to channel and contact engineering, offering a path for TMD transistors to become industrially relevant.
Cognitive Framework for Blended Math-Science Sensemaking for Vectors, Vector Operations, and Integrals
Keywords: Physics
Cognitive Framework
Blended Math-Science Sensemaking
Vectors
Vector Operations
Integrals
Electricity and Magnetism (E&amp;M)
Text
Thesis

Blended mathematical sensemaking in science (blended MSS) involves developing a conceptual understanding of quantitative relationships and the scientific meaning of equations describing phenomena. In recent work, Kaldaras & Wieman developed and provided initial validity evidence for a unified cognitive framework (the framework) for blended MSS across various scientific disciplines, including Physics and Chemistry. The framework describes increasingly sophisticated ways of engaging in blended MSS as students develop an equation describing the scientific phenomenon or build a deeper understanding of the known equation describing the phenomenon. Kaldaras and Wieman validated the framework for simple mathematical relationships describing scientific phenomena involving multiplication, division, subtraction, and addition. In my senior thesis, I am extending the framework by Kaldaras & Wieman to include mathematical relationships describing phenomena that include vectors, vector operations, and integrals. I will present initial validity evidence for my framework grounded in analysis of student interviews. I use my cognitive framework to investigate whether taking vector calculus and intro electricity and magnetism (E&M) in separate contexts or courses that do not support blended MSS is effective in helping students build an integrated understanding of physics phenomena involving vectors, vector operations, and integrals. The interview analysis showed evidence for the validity of most of the levels of my framework for vectors, vector operations, and integrals. Interview analysis results showed no significant difference in the ability to engage in blended MSS between students who took intro E&M and students who did not. This finding suggests that intro E&M does not sufficiently prepare students to engage in higher levels of blended MSS for physics phenomena involving vectors, vector operations, and integrals.