2,172 Works

Slender-Body Hypervelocity Boundary-Layer Instability

Nicholaus J. Parziale
With novel application of optical techniques, the slender-body hypervelocity boundary-layer instability is characterized in the previously unexplored regime where thermo-chemical effects are important. Narrowband disturbances (500-3000~kHz) are measured in boundary layers with edge velocities of up to 5~km/s at two points along the generator of a 5 degree half angle cone. Experimental amplification factor spectra are presented. Linear stability and PSE analysis is performed, with fair prediction of the frequency content of the disturbances; however,...

Terahertz and Microwave Spectroscopy of Liquids and Hydrogen-Bonded Clusters

Ian Alan Finneran
The microwave (MW, 0.3-100 GHz) and terahertz (THz, 0.1-10 THz) regions of the electromagnetic spectrum are replete with a rich set of molecular motions, including soft inter- and intramolecular vibrations, torsions, and rotations. At room temperature these motions are well populated, and play an active role in condensed-phase chemistry on Earth. This work details the development of one MW and two THz spectrometers along with their application to the study of liquids and hydrogen-bonded clusters....

The Absorption Coefficient of Hard Gamma-Rays

Chung-Yao Chao
The relation between the frequency of hard radiations and the absorption co-efficient is not experimentally well established at the present time. In the following work the absorption coefficient of γ-rays of ThC" is carefully investigated owing to their homogeneity. As a result, the observed absorption coefficient of light elements is found to agree fairly well with the theoretical formula of Klein and Nishina. Running from low to high atomic numbers, the absorption per electron is,...

Membrane Potential Dynamics of Hippocampal Neurons During Ripples in Awake Mice

Bradley Kline Hulse
During periods of slow wave sleep and quiet wakefulness, the hippocampal formation generates spontaneous population bursts that are organized as a high-frequency “ripple” oscillation. The neurons that participate in these bursts often replay previously experienced activity patterns encoded during alert behavior, and interfering with ripple generation produces deficits in learning and memory tasks. For these reasons, ripples play a prominent role in theories of memory consolidation and retrieval. While spiking during ripples has been extensively...

Flashover of Insulation in Homogenous Electric Fields

George K. Surrapas Diamos & William Abbett Lewis
No Abstract.

Electromechanical Properties of 3D Multifunctional Nano-Architected Materials

Max Louis Lifson
In this thesis, we explore the fabrication and characterization of 3D architected multifunctional materials in three different categories: varied density for tailored mechanical response, stiff ultra low-k dielectric materials, and direct laser writing of piezoelectric structures at the micron scale. The density of an architected material plays a large role in determining its effective Young’s modulus, strength, and deformation behavior. The first section of this work explores the effect of incorporating two density regions into...

On Ultrafast Time-Domain TeraHertz Spectroscopy in the Condensed Phase: Linear Spectroscopic Measurements of Hydrogen-Bond Dynamics of Astrochemical Ice Analogs and Nonlinear TeraHertz Kerr Effect Measurements of Vibrational Quantum Beats

Marco Alberto Allodi
Much of the chemistry that affects life on planet Earth occurs in the condensed phase. The TeraHertz (THz) or far-infrared (far-IR) region of the electromagnetic spectrum (from 0.1 THz to 10 THz, 3 cm-1 to 300 cm-1, or 3000 μm to 30 μm) has been shown to provide unique possibilities in the study of condensed-phase processes. The goal of this work is to expand the possibilities available in the THz region and undertake new investigations...

Software Design System

Computer Science Technical Reports

Algorithmic Challenges in Green Data Centers

Minghong Lin
With data centers being the supporting infrastructure for a wide range of IT services, their efficiency has become a big concern to operators, as well as to society, for both economic and environmental reasons. The goal of this thesis is to design energy-efficient algorithms that reduce energy cost while minimizing compromise to service. We focus on the algorithmic challenges at different levels of energy optimization across the data center stack. The algorithmic challenge at the...

Charged Pion Contribution to the Anomalous Magnetic Moment of the Muon

Kevin Thomas Engel
The model dependence inherent in hadronic calculations is one of the dominant sources of uncertainty in the theoretical prediction of the anomalous magnetic moment of the muon. In this thesis, we focus on the charged pion contribution and turn a critical eye on the models employed in the few previous calculations of $a_\mu^{\pi^+\pi^-}$. Chiral perturbation theory provides a check on these models at low energies, and we therefore calculate the charged pion contribution to light-by-light...

Multilayer Active Shell Mirrors

John Bradley Steeves
This thesis presents a novel active mirror technology based on carbon fiber composites and replication manufacturing processes. Multiple additional layers are implemented into the structure in order to provide the reflective layer, actuation capabilities and electrode routing. The mirror is thin, lightweight, and has large actuation capabilities. These features, along with the associated manufacturing processes, represent a significant change in design compared to traditional optics. Structural redundancy in the form of added material or support...

Theory of Plasma Wave Resonances in a Hot Nonuniform Plasma

Jerald V. Parker
This work is concerned with the resonant motion exhibited by a plasma column which is excited by an oscillating electric field transverse to the column. A theory is considered which includes the effects of electron temperature and of nonuniformities in the plasma electron density. In order to have a quantitative theory, the nonuniform electron densities used are calculated numerically using a theory due to Tonks and Langmuir. The theory yields a fourth order differential equation...

Surface Drawing

Computer Science Technical Reports

Essays on the Impact of Information Asymmetry

Myungkoo Song
This dissertation consists of three essays focusing on how information asymmetry affects agents’ behavior across different environments. The first essay characterizes the optimal contract when a firm can employ two incentive schemes, promotion and pay for performance, simultaneously (Chapter 2). In the second essay, I study how information asymmetry can lead a firm to choose a less profitable short-term over a more profitable long-term project (Chapter 3). The other essay analyzes a career choice problem...

Fauna of the Merychippus Zone, North Coalinga District, California. The Structural Geology of the San Joaquin Hills, Orange County, California

Francis Dashwood Bode
[Major thesis] Fauna of the Merychippus zone, north Coalinga district, California: The Merychippus zone occurs at the top of the Temblor sandstones on Domengine Creek, twelve miles north of Coalinga, California. The fauna includes a significant representation of ungulates and carnivores, with the Equidae far outnumbering all other forms. The stratigraphic position of the Merychippus zone in the Tertiary marine series, exposed on the west side of the San Joaquin Valley, lies within a zone...

Search for SUSY with Delayed Photons at the Compact Muon Solenoid

Gillian Baron Kopp
The Compact Muon Solenoid (CMS) experiment records data from proton-proton (pp) and heavy ion (Pb-Pb and Pb-p) collisions at the Large Hadron Collider (LHC) to search for physics beyond the Standard Model, test theories of supersymmetry (SUSY), and measure properties of known particles with higher precision. In 2025, the LHC will be upgraded to the High Luminosity LHC (HL-LHC), where the luminosity will be increased by a factor of 10. This will increase the number...

Pliocene Conglomerates of the Los Angeles Basin and their Paleographic Significance. Foraminifera of the Repetto Hills

Everett Carlyle Edwards
Pliocene conglomerates of the Los Angeles basin and their paleographic significance: The Los Angeles Basin of southern California is 50 miles long and 25 miles wide, and is bounded by the Pacific Ocean, the Santa Monica, San Gabriel and Santa Ana Mountains and the Ferris Block. It contains an enormous thickness of Miocene, Pliocene and Pleistocene strata. Physical conditions of origin and the nature of sediments are as closely related as cause and effect. Since...

Convex Relaxation for Low-Dimensional Representation: Phase Transitions and Limitations

Samet Oymak
There is a growing interest in taking advantage of possible patterns and structures in data so as to extract the desired information and overcome the curse of dimensionality. In a wide range of applications, including computer vision, machine learning, medical imaging, and social networks, the signal that gives rise to the observations can be modeled to be approximately sparse and exploiting this fact can be very beneficial. This has led to an immense interest in...

The Colorado River - a Source of Water and Power for Los Angeles

Max W. Moody
The rapid growth and development of Los Angeles City and County has been one of the phenomena of the present age. The growth of a city from 50,600 to 576,000, an increase of over 1000% in thirty years is an unprecedented occurrence. It has given rise to a variety of problems of increasing magnitude. Chief among these are: supply of food, water and shelter development of industry and markets, prevention and removal of downtown congestion...

Thermalization in Periodically-Driven Interacting Quantum Systems

Karthik Iyengar Seetharam
Periodically-driven (Floquet) quantum systems are ubiquitous in science and technology. For example, when a laser illuminates a material or an AC voltage is applied to a device, the system is well-described by a time-periodic Hamiltonian. In recent years, periodic driving has been proposed, not just as a tool to excite and probe devices, but actually as a mechanism of engineering new phases of matter, some of which have no equilibrium analog. However, with this promise...

Microbial Evolution and the Rise of Oxygen: The Roles of Contingency and Context in Shaping the Biosphere through Time

Lewis Michael Ward
We are shaped by our environment, but we then shape it in turn. This interplay between life and the Earth, and how these interactions have shaped both parties through time, is the heart of the discipline of geobiology. My research is fundamentally motivated by a desire to understand how life and the Earth have changed together through time to reach the state that they’re at today, and to understand from this history how the coevolution...

New Insights into Circumstellar Disk Evolution in the Era of ALMA

Scott Alexander Barenfeld
In recent decades, it has become clear that solar systems such as our own form within the circumstellar disks of gas and dust that surround young stars. Thus, to understand how these solar systems come to be, it is necessary to study the conditions within these disks. Until recently, such studies have required a focus on intrinsically brighter and younger disks that are easier to observe. However, a full picture of planet formation requires the...

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