27 Works

Comments on Philippe de la Hire’s Memoir on Arch Abutment Design (1712)

John F. Hall
Philippe de la Hire (1640-1718), a multi-disciplinary French scientist, is generally credited as being the first person to apply the principles of statics to the analysis and design of arches. Prior efforts employed geometric design rules that were based on experience. Thus, de la Hire plays an important role in the transition to scientifically based methods for civil engineering structures. Therefore, it is of historical interest to understand de la Hire’s approach and perspective.

Political Networks

Deborah Elizabeth (Betsy) Sinclair
This dissertation examines the degree to which relationships between individuals determine their political behavior. The dissertation finds, through theoretical and experimental examination, that the political context within which an individual exists affects their preferences. Additionally, using a series of canonical data-sets the correlation between context and preferences is revealed to be a consequence of the information voters obtain via horizontal voter-to-voter communication. The dissertation is divided into five sections, each of which uses a distinct...

Progress toward the Development of a Single Molecule Transistor with Graphene Electrodes

Emma Rose Schmidgall
Single molecule transistors are useful for studying both the charge and spin states of molecules. These devices consist of a nanogap with three contacts for the source, drain, and gate. Current versions use metallic contacts for the source and drain, which remain essentially three dimensional. It is thought that graphene contacts for the source and drain, which would he atomically tlat, would enable the observation of more molecular charge states due to reduced screening between...

Laser Offset Stabilization for Broadly Tunable TeraHertz (THz) Frequency Generation

Kevin Cossel
Spectroscopy and imaging in the terahertz region promises to be useful for a wide variety of applications. For remote sensing, terahertz spectroscopy could help in the identification of explosives and narcotics. In astronomy, terahertz imaging should provide new information about the composition of the interstellar medium and about the processes by which stars and planets are born. In chemistry and molecular biology, terahertz spectroscopy provides new rotational or rovibrational spectra of molecules and is useful...

Mechanics of River Avulsions on Lowland River Deltas

Austin John Chadwick
Lowland deltas are home to over 0.5 billion people and some of the most biodiverse ecosystems on Earth. Deltas are highly dynamic landscapes, and at the largest scale grow through repeated construction of depositional lobes punctuated by river avulsions – abrupt shifts in river course to the shoreline. River avulsions have been responsible for dangerous floods and civil unrest over human history, but also counter land loss due to sea-level rise and coastal subsidence by...

Suspension Mechanics: I. Inertial and Non-Newtonian Migration of Neutrally Buoyant Rigid Spheres in Two-Dimensional Unidirectional Flows. II. The Effect of Viscoelasticity on the Creeping Motion of a Train of Neutrally Buoyant Newtonian Drops through a Circular Tube

Bosco Po-Wai Ho
The lateral migration of neutrally buoyant rigid spheres in two-dimensional unidirectional flows was studied theoretically. The cases of both inertia-induced migration in a Newtonian fluid and normal stress-induced migration in a second-order fluid were considered. Analytical results for the lateral velocities were obtained, and the equilibrium positions and trajectories of the spheres compared favorably with the experimental data available in the literature. The effective viscosity was obtained for a dilute suspension of spheres which were...

Resonance Cones and Mode Conversion in a Warm Magnetized Bounded Plasma

Crockett Lane Grabbe
The warm plasma resonance cone structure of the quasistatic field produced by a gap source in a bounded magnetized slab plasma is determined theoretically. This is initially determined for a homogeneous or mildly inhomogeneous plasma with source frequency lying between the lower hybrid frequency and the plasma frequency. It is then extended to the complicated case of an inhomogeneous plasma with two internal lower hybrid layers present, which is of interest to radio frequency heating...

Local-to-Global in Multi-Agent Systems

Concetta Pilotto
The thesis presents performance analysis and simulation results for algorithms that compute global functions out of local interactions on multi-agent systems. We focus on optimization problems; this is because many problems can be formulated in terms of designing algorithms which optimize some global function subject to local constraints. We model the environment as an adversary of the system. The environment is able to attack the system, modifying the system in arbitrary ways: some agents and/or...

Convex Relaxations for Graph and Inverse Eigenvalue Problems

Utkan Onur Candogan
This thesis is concerned with presenting convex optimization based tractable solutions for three fundamental problems: 1. Planted subgraph problem: Given two graphs, identifying the subset of vertices of the larger graph corresponding to the smaller one. 2. Graph edit distance problem: Given two graphs, calculating the number of edge/vertex additions and deletions required to transform one graph into the other. 3. Affine inverse eigenvalue problem: Given a subspace ε ⊂ 𝕊ⁿ and a vector of...

Geological Evolution of Two Crustal Scale Shear Zones: Part I: The Rand Thrust Complex, Northwestern Mojave Desert, California. Part II: The Magdalena Metamorphic Core Complex, North Central Sonora, Mexico

Jonathan Alan Nourse
The geology and structure of two crustal scale shear zones were studied to understand the partitioning of strain within intracontinental orogenic belts. Movement histories and regional tectonic implications are deduced from observational data. The two widely separated study areas bear the imprint of intense Late Mesozoic through Middle Cenozoic tectonic activity. A regional transition from Late Cretaceous-Early Tertiary plutonism, metamorphism, and shortening strain to Middle Tertiary extension and magmatism is preserved in each area, with...

Quantum Correlations, Certifying Quantum Devices, and the Quest for Infinite Entanglement

Andrea Wei Coladangelo
Quantum information has the potential to disrupt the present computational landscape. Much of this potential rests on the existence of efficient quantum algorithms for classically intractable problems and of quantum cryptographic protocols for tasks that are provably impossible to realize classically. At the heart of many quantum advantages is one of the most counterintuitive features of quantum mechanics, known as entanglement. The central motivating question of this thesis is the following: if quantum devices will...

Phase Transitions in Materials: Advanced Topics

Brent Fultz
This book explains the thermodynamics and kinetics of most of the important phase transitions in materials science. It is a textbook, so the emphasis is on explanations of phenomena rather than a scholarly assessment of their origins. The goal is explanations that are concise, clear, and reasonably complete. The level and detail are appropriate for upper division undergraduate students and graduate students in materials science and materials physics. The book should also be useful for...

Resistance is Futile: Physical Science, Systems Biology and Single-Cell Analysis to Understanding the Plastic and Heterogeneous Nature of Melanoma and Their Role in Non-Genetic Drug Resistance

Yapeng Su
Melanoma is the most deadly form of skin cancer due to its great metastatic potential. Targeted therapy that inhibits the BRAF-V600E driver mutation has shown impressive initial responses in melanoma patients. However, drug resistance, as the universal phenomenon for any cancer therapy, always limits treatment efficacy and compromises outcomes. As the early-step of resistance development, non-genetic mechanisms enable cancer cells to transition into a drug-resistant state in as early as a few days after drug...

Mechanistic Studies of Alkane Activation by Platinum(II) Complexes

Shannon Scot Stahl
Currently, there is considerable interest in alkane oxidation reactions catalyzed by transition metal complexes. Chapter 1 reviews many of the recent advances in this field involving electrophilic late transition metals. The C-H activation step appears to dictate both the rate and selectivity of these reactions. Unfortunately, however, very little is known about the mechanism of this step. In chapter 2, mechanistic studies of the protonolysis of several alkylplatinum(II) complexes [(tmeda)PtMeCl, (tmeda)Pt(CH2Ph)Cl, (tmeda)PtMe2, and trans(PEt3)2Pt(CH3)Cl] are...

Thermal Conduction in Amorphous Materials and the Role of Collective Excitations

Jaeyun Moon
The atomic vibrations and thermal properties of amorphous dielectric solids are of fundamental and practical interest. For applications, amorphous solids are widely used as thermal insulators in thermopile and other detectors where low thermal conductivity directly sets the sensitivity of the detector. Amorphous solids are of fundamental interest themselves because the lack of atomic periodicity complicates theoretical development. As a result, the lower limits of thermal conductivity in solids as well as the nature of...

Visualizing Small Proteins with the cryoEM Platform and The Structure of the Vibrio cholerae Type IV Competence Pilus Secretin PilQ

Sara Jean Weaver
Solving protein structures by single-particle cryoelectron microscopy (cryo-EM) has become a crucial tool in structural biology. While exciting progress is being made toward the visualization of small macromolecules, the median protein size in both eukaryotes and bacteria is still beyond the reach of cryo-EM. To overcome this problem, we implemented a platform strategy in which a small protein target was rigidly attached to a large, symmetric base via a selectable adapter. Of our seven designs,...

Hunting for Hidden Explosions: Exploring the Transient Infrared Sky with the Spitzer Space Telescope

Jacob Edmund Jencson
The study of time-variable astronomical phenomena is undergoing an explosive renaissance ushered in by recent advancements in capabilities to monitor the sky from radio to gamma rays. The infrared region of the electromagnetic spectrum provides a unique window to uncover a vast array of stellar eruptions and explosions that are otherwise obscured; however, the dynamic infrared sky has remained largely unexplored. To uncover these hidden cosmic explosions, I undertook a systematic search in the infrared...

High-Cycle Dynamic Cell Fatigue with Applications on Oncotripsy

Erika Figueroa-Schibber
The method of oncotripsy (from Greek, onco- meaning "tumor" and –tripsy "to break") exploits aberrations in the material properties and morphology of cancerous cells to target them selectively using tuned low-intensity pulsed ultrasound. Compared to other noninvasive ultrasound treatments that ablate malignant tissue, oncotripsy has the capability of targeting unhealthy tissue with minimal damage to healthy cells in the ablation process. We propose a model of oncotripsy that follows as an application of cell dynamics,...

Seismic Waveform Modeling of Natural Hazards and Sharp Structural Boundaries

Voon Hui Lai
Seismic waveform modeling is a powerful tool for seismologists to learn about the Earth’s dynamics, either how a natural hazard evolves with time, or the long-term deformation process governed by fine-scale structures along boundaries inside the Earth. Knowing that the recorded seismograms reflect the cumulative effects of the source, the earth structure, and the instrument response, I carefully study the characters of the seismograms such as the arrival time, amplitude, frequency content, and multipathing, for...

Scanning Tunneling Microscopy and Spectroscopy of Silicon and Carbon Surfaces

Shenda Mary Baker
Scanning Tunneling Microscopy (STM) investigations and additional surface analyses were performed on carbon and silicon surfaces. A number of anomalies have been observed on highly oriented pyrolytic graphite (HOPG), including large corrugations, distorted images, large range of tip motion and the absence of defects. A mechanism involving direct contact between tip and sample or contact through a contamination layer to provide an additional conduction pathway is proposed. This model of point-contact imaging provides an explanation...

Boundary Integral Equation Methods for Simulation and Design of Photonic Devices

Emmanuel Garza
This thesis presents novel boundary integral equation (BIE) and associated optimization methodologies for photonic devices. The simulation and optimization of such structures is a vast and rapidly growing engineering area, which impacts on design of optical devices such as waveguide splitters, tapers, grating couplers, and metamaterial structures, all of which are commonly used as elements in the field of integrated photonics. The design process has been significantly facilitated in recent years on the basis of...

Radiation from an Electric Dipole in an Anisotropic Cold Plasma

Hans H. Kuehl
The general expression for the far-zone dyadic Green's function in an anisotropic medium is presented. The radiation of an electric dipole in a cold plasma is considered. Expressions for the far-zone radiation from a dipole for the case of weak magnetic field and low plasma density are derived. Expressions are also obtained for the case of an infinite magnetic field.

GW190425: Strain and Data Quality Data Set observed by LIGO and Virgo

LIGO Scientific Collaboration and VIRGO Collaboration

Current on an Infinitely Long Cylindrical Antenna

Hans H. Kuehl
The infinitely long circular cylindrical antenna driven at some cross section by a localized electromotive force, V, circumscribing the cylinder in a peripheral band is considered. The asymptotic expression for the current at large distances from the driving e.m.f. is derived using the saddle point method. It is shown that the amplitude of this current is proportional to the reciprocal of the logarithm of axial distance from the driving e.m.f.

Radiation Patterns of the Noise Emission from a Gaseous Discharge

Nick George
Theoretical and experimental radiation patterns are given in spectral form for the thermal radiation from a cylindrical discharge column which is adjacent to a long thin slot in a metallic plane. A spatial distribution is predicted which exhibits interference minima and maxima when the length of the slot and the wavelength of the emission are the same order of magnitude. The analysis is based on Maxwell's equations and the Leontovich-Rytov distributed-source generalization of Nyquist's noise...

Registration Year

  • 2020
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Resource Types

  • Text
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Affiliations

  • California Institute of Technology
    2