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Full-Text Articles in Physics

Detrital Zircon Geochronology And Evolution Of The Nacimiento Block Late Mesozoic Forearc Basin, Central California Coast, Scott Johnston, Andrew R.C. Kylander-Clark, Alan D. Chapman Dec 2018

Detrital Zircon Geochronology And Evolution Of The Nacimiento Block Late Mesozoic Forearc Basin, Central California Coast, Scott Johnston, Andrew R.C. Kylander-Clark, Alan D. Chapman

Physics

Forearc basins are first-order products of convergent-margin tectonics, and their sedimentary deposits offer unique perspectives on coeval evolution of adjacent arcs and subduction complexes. New detrital zircon U-Pb geochronologic data from 23 sandstones and 11 individual conglomerate clasts sampled from forearc basin strata of the Nacimiento block, an enigmatic stretch of the Cordilleran forearc exposed along the central California coast, place constraints on models for forearc deformation during evolution of the archetypical Cordilleran Mesozoic margin. Deposition and provenance of the Nacimiento forearc developed in three stages: (1) Late Jurassic– Valanginian deposition of lower Nacimiento forearc strata with zircon derived from …


Geologic Map And Structural Development Of The Noerthernmost Sur-Nacimiento Fault Zone, Central California Coast, Scott M. Johnston, John S. Singleton, Alan D. Chapman, Gabriella Murray Dec 2018

Geologic Map And Structural Development Of The Noerthernmost Sur-Nacimiento Fault Zone, Central California Coast, Scott M. Johnston, John S. Singleton, Alan D. Chapman, Gabriella Murray

Physics

The Sur-Nacimiento fault exposed along the central California coast (United States) juxtaposes the Salinian block arc against the Nacimiento block accretionary complex, cuts out the majority of the forearc basin and western arc, and requires a minimum of 150 km of orogen-normal crustal excision within the Mesozoic California convergent margin. Despite this significant strain, the kinematic evolution of the Sur-Nacimiento fault remains poorly understood, with diverse hypotheses suggesting sinistral, dextral, thrust, or normal displacement along the fault. This Late Cretaceous–Paleogene strain history is complicated by the location of the fault within a belt of subparallel faults that have accommodated significant …


Revealing The Broad Line Region Of Ngc 1275: The Relationship To Jet Power, Brian Punsly, Paola Marziani, Vardha Nicola Bennert, Hiroshi Nagai, Mark A. Gurwell Dec 2018

Revealing The Broad Line Region Of Ngc 1275: The Relationship To Jet Power, Brian Punsly, Paola Marziani, Vardha Nicola Bennert, Hiroshi Nagai, Mark A. Gurwell

Physics

NGC 1275 is one of the most conspicuous active galactic nuclei (AGN) in the local universe. The radio jet currently emits a flux density of ~10 Jy at ~1 mm wavelengths, down from the historic high of ~65 Jy in 1980. Yet, the nature of the AGN in NGC 1275 is still controversial. It has been debated whether this is a broad emission line (BEL) Seyfert galaxy, an obscured Seyfert galaxy, a narrow line radio galaxy, or a BL Lac object. We clearly demonstrate a persistent Hβ BEL over the last 35 yr with a full width at half …


Validation Of The Nonhydrostatic General Curvilinear Coastal Ocean Model (Gccom) For Stratified Flows, Mariangel Garcia, Paul Choboter, Ryan K. Walter, Jose E. Castillo Nov 2018

Validation Of The Nonhydrostatic General Curvilinear Coastal Ocean Model (Gccom) For Stratified Flows, Mariangel Garcia, Paul Choboter, Ryan K. Walter, Jose E. Castillo

Physics

While global- and basin-scale processes can be captured quite well with computationally-inexpensive hydrostatic models, smaller-scale features such as shoaling nonlinear internal waves and bores, coastal fronts, and other convective processes require the use of a nonhydrostatic model to accurately capture dynamics. Here the nonhydrostatic capabilities of the General Curvilinear Coastal Ocean Model (GCCOM) in a stratified environment are introduced. GCCOM is a three-dimensional, nonhydrostatic Large Eddy Simulation (LES), rigid lid model that has the ability to run in a fully three-dimensional general curvilinear coordinate system. This model was previously validated for unstratified flows with curvilinear coordinates. Here, recent advances of …


Studying The [O Iii]Λ5007 Å Emission-Line Width In A Sample Of ∼ 80 Local Active Galaxies: A Surrogate For Σ⋆?, Vardha Nicola Bennert, Donald Loveland, Edward Donohue, Maren Cosens, Sean Lewis, S. Komossa, Tommaso Treu, Matthew A. Malkan, Nathan Milgram, Kelsi Flatland, Matthew W. Auger, Daesong Park, Mariana S. Lazarova Nov 2018

Studying The [O Iii]Λ5007 Å Emission-Line Width In A Sample Of ∼ 80 Local Active Galaxies: A Surrogate For Σ⋆?, Vardha Nicola Bennert, Donald Loveland, Edward Donohue, Maren Cosens, Sean Lewis, S. Komossa, Tommaso Treu, Matthew A. Malkan, Nathan Milgram, Kelsi Flatland, Matthew W. Auger, Daesong Park, Mariana S. Lazarova

Physics

For a sample of ∼ 80 local (0.02 ≤ z" role="presentation">z ≤ 0.1) Seyfert-1 galaxies with high-quality long-slit Keck spectra and spatially resolved stellar-velocity dispersion (σ) measurements, we study the profile of the [O iii]λ5007 Å emission line to test the validity of using its width as a surrogate for σ. Such an approach has often been used in the literature, since it is difficult to measure σ for type-1 active galactic nuclei (AGNs) due to the AGN continuum outshining the stellar-absorption lines. Fitting the [O iii] line with a single Gaussian or Gauss–Hermite …


Mountaintop Neutrino Detection: A Nu(Tau) Concept, Caroline E. Paciaroni Nov 2018

Mountaintop Neutrino Detection: A Nu(Tau) Concept, Caroline E. Paciaroni

Physics

High-energy neutrinos traveling from the distant universe produce detectable signals at radio frequencies after interacting with the earth or its atmosphere. This is the principle behind a new experiment, the BEamforming Elevated Array for COsmogenic Neutrinos, or BEACON. BEACON will be a high altitude array of antennas that is sensitive to up-going tau neutrinos ($\nu_{\tau}$). These elementary particles serve as sources of information about the extraordinarily high energy events in the universe that create them, and also the laws of particle physics that govern their behavior. This report details the construction of a transient detector used to characterize site locations …


Assessment Of Surface Wind Datasets For Estimating Offshore Wind Energy Along The Central California Coast, Yi-Hui Wang, Ryan K. Walter, Crow White, Hayley Farr, Benjamin I. Ruttenberg Oct 2018

Assessment Of Surface Wind Datasets For Estimating Offshore Wind Energy Along The Central California Coast, Yi-Hui Wang, Ryan K. Walter, Crow White, Hayley Farr, Benjamin I. Ruttenberg

Physics

In the United States, Central California has gained significant interest in offshore wind energy due to its strong winds and proximity to existing grid connections. This study provides a comprehensive evaluation of near-surface wind datasets in this region, including satellite-based observations (QuikSCAT, ASCAT, and CCMP V2.0), reanalysis (NARR and MERRA), and regional atmospheric models (WRF and WIND Toolkit). This work highlights spatiotemporal variations in the performance of the respective datasets in relation to in-situ buoy measurements using error metrics over both seasonal and diurnal time scales. The two scatterometers(QuikSCAT and ASCAT) showed the best overall performance, albeit with significantly …


The Lick Agn Monitoring Project 2011: Dynamical Modeling Of The Broad-Line Region, Peter R. Williams, Anna Pancoast, Tommaso Treu, Brendon J. Brewer, Vardha N. Bennert, Jong-Hak Woo Oct 2018

The Lick Agn Monitoring Project 2011: Dynamical Modeling Of The Broad-Line Region, Peter R. Williams, Anna Pancoast, Tommaso Treu, Brendon J. Brewer, Vardha N. Bennert, Jong-Hak Woo

Physics

We present models of the Hβ-emitting broad-line region (BLR) in seven Seyfert 1 galaxies from the Lick AGN Monitoring Project 2011 sample, drawing inferences on the BLR structure and dynamics as well as the mass of the central supermassive black hole. We find that the BLR is generally a thick disk, viewed close to face-on, with preferential emission back toward the ionizing source. The dynamics in our sample range from near-circular elliptical orbits to inflowing or outflowing trajectories. We measure black hole masses of for PG 1310−108, for Mrk 50, for Mrk 141, for Mrk 279, for Mrk …


Reversible Motion In A Contact Line, Audrey Profeta, Esmeralda Orozco, Juan A. Ortiz Salazar, Dani Medina, Nathan C. Keim Sep 2018

Reversible Motion In A Contact Line, Audrey Profeta, Esmeralda Orozco, Juan A. Ortiz Salazar, Dani Medina, Nathan C. Keim

STAR Program Research Presentations

When a body of liquid sits on a surface, an irregular border between the wet and dry regions of the surface exists, called the contact line. Driving this contact line back and forth repeatedly can change its shape.We use a syringe pump to cyclically infuse and withdraw a predetermined volume of water, and take photos of the contact line after each cycle. Comparing these images to each other determines if the contact line is returning to the same shape. We find that below a critical value of infused volume, after many cycles the contact line reaches a steady state in …


Hydrodynamics In A Shallow Seasonally Low-Inflow Estuary Following Eelgrass Collapse, Ryan K. Walter, Edwin J. Rainville, Jennifer K. O'Leary Aug 2018

Hydrodynamics In A Shallow Seasonally Low-Inflow Estuary Following Eelgrass Collapse, Ryan K. Walter, Edwin J. Rainville, Jennifer K. O'Leary

Physics

Hydrodynamics play a critical role in mediating biological and ecological processes and can have major impacts on the distribution of habitat-forming species. Low-inflow estuaries are widespread in arid regions and during the dry season in Mediterranean climates. There is a growing need to evaluate dynamics and exchange processes in these systems and the resultant ecological linkages. We investigate the role that hydrodynamics play in shaping environmental gradients in a short and seasonally low-inflow estuary located along the central California coast. Since 2007, eelgrass meadows in Morro Bay have declined by more than 90%, representing the collapse of the major …


Anisotropic Conductive Adhesives For Interdigitated Back Contact (Ibc) Silicon Solar Cells, Katherine M. Lohmuste, Manuel Schnabel, Maikel F.A.M. Van Hest Aug 2018

Anisotropic Conductive Adhesives For Interdigitated Back Contact (Ibc) Silicon Solar Cells, Katherine M. Lohmuste, Manuel Schnabel, Maikel F.A.M. Van Hest

STAR Program Research Presentations

The current manufacturing process for solar panels using interdigitated back contact (IBC) silicon solar cells involves a multi-step metallization and interconnection process in which a substantial amount of silver is used. This work focuses on a new process using conductive adhesives (CA) which would increase efficiency and lower cost through a one-step metallization and interconnection process that combines with encapsulation using little silver and only requiring metal patterning on the back sheet or back glass. It would also not require direct metallization of the silicon, which would result in fewer defects, while increasing voltage and therefore efficiency. Silver-coated Poly(Methyl Methacrylate) …


Calibration And Limitations Of The Mg Ii Line-Based Black Hole Masses, Jong-Hak Woo, Huynh Anh N. Le, Marios Karouzos, Dawoo Park, Daesong Park, Matthew A. Malkan, Tommaso Treu, Vardha Nicola Bennert Jun 2018

Calibration And Limitations Of The Mg Ii Line-Based Black Hole Masses, Jong-Hak Woo, Huynh Anh N. Le, Marios Karouzos, Dawoo Park, Daesong Park, Matthew A. Malkan, Tommaso Treu, Vardha Nicola Bennert

Physics

We present single-epoch black hole mass () calibrations based on the rest-frame ultraviolet (UV) and optical measurements of Mg ii 2798 Å and Hβ 4861 Å lines and the active galactic nucleus (AGN) continuum, using a sample of 52 moderate-luminosity AGNs at z ~ 0.4 and z ~ 0.6 with high-quality Keck spectra. We combine this sample with a large number of luminous AGNs from the Sloan Digital Sky Survey to increase the dynamic range for a better comparison of UV and optical velocity and luminosity measurements. With respect to the reference based on the line dispersion of H …


Heavy Flavour In Jets And Azimuthal Correlations, Patrick J. Steffanic Jun 2018

Heavy Flavour In Jets And Azimuthal Correlations, Patrick J. Steffanic

Physics

We studied heavy-flavor azimuthal correlations using the semi-leptonic decay channel of hard-scattered bottom quarks in proton-proton collisions at center-of-mass energies of 7 TeV. We used a mixed-event method to produce a corrected correlation that hinted at back-to-back pair production. We further studied the jets resulting from these heavy-flavor hard scatterings, and jets resulting from light-flavor and gluon scattering. We compared several kinematic variables from each of the jet populations, concluding that novel kinematic variables must be developed in order to effectively separate the jet populations.


Assembling And Characterizing The Efficiency Of An Injection Locked Laser System For Cold Neutral Atom Optical Traps, Alexandra Papa Crawford Jun 2018

Assembling And Characterizing The Efficiency Of An Injection Locked Laser System For Cold Neutral Atom Optical Traps, Alexandra Papa Crawford

Physics

Creating a quantum computer requires a system of particles that can be well-controlled to achieve quantum operations. We need a large array of these particles – called qubits – with long coherence times, which can be initialized, operated on by single and two qubit gates, and read out. For neutral atoms, the qubit states are stable ground states that interact minimally with the environment, leading to long coherence times. Experimentally, the qubits are manipulated using carefully timed laser beam pulses with controlled frequency and intensity, but the outstanding issue for optically trapping cold atoms is finding a light pattern that …


Cuoricino Thermal Pulse Classification By Machine Learning Algorithms, Joshua Mann Jun 2018

Cuoricino Thermal Pulse Classification By Machine Learning Algorithms, Joshua Mann

Physics

Many of the various properties of neutrinos are still a mystery. One unknown is whether neutrinos are Majorana fermions or Dirac fermions. Cuoricino and CUORE are experiments that aim to solve this mystery. Noise reduction in these experiments hinges on the ability to discern among alpha, beta and gamma particle detections using the thermal pulses they create. In this paper, we look at Cuoricino data and attempt to classify pulses, not as alpha, beta or gamma particles, but rather as signal, noise or calibration data. We will use this preliminary testing ground to examine various machine learning algorithms' abilities in …


Pseudo Power Law Statistics In A Jammed, Amorphous Solid, Jacob Brian Hass Jun 2018

Pseudo Power Law Statistics In A Jammed, Amorphous Solid, Jacob Brian Hass

Physics

Simulations have shown that in many solid materials, rearrangements within the solid obey power-law statistics. A connection has been proposed between these statistics and the ability of a system to reach a limit cycle under cyclic driving. We study experimentally a 2D jammed solid that reaches such a limit cycle. Our solid consists of microscopic plastic beads adsorbed at an oil-water interface and cyclically sheared by a magnetically driven needle. We track each particles trajectory in the solid to identify rearrangements. By associating particles both spatially and temporally, we can measure the extent of each rearrangement. We study specifically the …


Simulating The Electrical Properties Of Random Carbon Nanotube Networks Using A Simple Model Based On Percolation Theory, Roberto Abril Valenzuela Jun 2018

Simulating The Electrical Properties Of Random Carbon Nanotube Networks Using A Simple Model Based On Percolation Theory, Roberto Abril Valenzuela

Physics

Carbon nanotubes (CNTs) have been subject to extensive research towards their possible applications in the world of nanoelectronics. The interest in carbon nanotubes originates from their unique variety of properties useful in nanoelectronic devices. One key feature of carbon nanotubes is that the chiral angle at which they are rolled determines whether the tube is metallic or semiconducting. Of main interest to this project are devices containing a thin film of randomly arranged carbon nanotubes, known as carbon nanotube networks. The presence of semiconducting tubes in a CNT network can lead to a switching effect when the film is electro-statically …


Influence Of Internal Bores On Larval Fish Abundance And Community Composition, Patrick J. Phelan, John Steinbeck, Ryan K. Walter Mar 2018

Influence Of Internal Bores On Larval Fish Abundance And Community Composition, Patrick J. Phelan, John Steinbeck, Ryan K. Walter

Physics

A persistent semidiurnal internal tidal bore feature occurs at the head of the Monterey Bay Submarine Canyon and drives regular intrusions of cold, subthermocline waters onto the adjacent shelf. In this study, we examine the influence of this internal tidal bore feature on the larval fish community using over a year of periodic larval fish samples collected coincidently with physical measurements. Larval samples were categorized into one of two water mass periods: a “warm period” representative of shallow coastal shelf waters and a “cold period” characteristics of colder waters present during internal bore forcing. Using multivariate statistical methods, we show …


Stability Of The Broad-Line Region Geometry And Dynamics In Arp 151 Over Seven Years, A. Pancoast, A. J. Barth, K. Horne, T. Treu, Vardha N. Bennert, H. Winkler Mar 2018

Stability Of The Broad-Line Region Geometry And Dynamics In Arp 151 Over Seven Years, A. Pancoast, A. J. Barth, K. Horne, T. Treu, Vardha N. Bennert, H. Winkler

Physics

The Seyfert 1 galaxy Arp 151 was monitored as part of three reverberation mapping campaigns spanning 2008–2015. We present modeling of these velocity-resolved reverberation mapping data sets using a geometric and dynamical model for the broad-line region (BLR). By modeling each of the three data sets independently, we infer the evolution of the BLR structure in Arp 151 over a total of 7 yr and constrain the systematic uncertainties in nonvarying parameters such as the black hole mass. We find that the BLR geometry of a thick disk viewed close to face-on is stable over this time, although the size …


Rental Property Energy Efficiency In San Luis Obispo, Zachary Earl Shockley Mar 2018

Rental Property Energy Efficiency In San Luis Obispo, Zachary Earl Shockley

Physics

In the modern era, many people choose to rent homes instead of purchasing a home. College towns have an even more disproportionate number of renters when compared to other cities. The majority of rental properties are much less energy efficient than their owner-occupied counterparts. This project analyzes the energy efficiency issues of rental properties in San Luis Obispo and examines potential ways to remedy these issues. In order to analyze these issues, the guiding principles of building science are first discussed, followed by case studies of rental properties in San Luis Obispo. These case studies examine multiple rental properties and …


Coastal Upwelling Seasonality And Variability Of Temperature And Chlorophyll In A Small Coastal Embayment, Ryan K. Walter, Kevin Armenta, Brandon Shearer, Ian C. Robbins, John Steinbeck Jan 2018

Coastal Upwelling Seasonality And Variability Of Temperature And Chlorophyll In A Small Coastal Embayment, Ryan K. Walter, Kevin Armenta, Brandon Shearer, Ian C. Robbins, John Steinbeck

Physics

While the seasonality of wind-driven coastal upwelling in eastern boundary upwelling systems has long been established, many studies describe two distinct seasons (upwelling and non-upwelling), a generalized framework that does not capture details relevant to marine ecosystems. In this contribution, we present a more detailed description of the annual cycle and upwelling seasonality for an understudied location along the central California coast. Using both the mean monthly upwelling favorable wind stress and the monthly standard deviation, we define the following seasons (contiguous months) and a transitional period (non-contiguous months): “Winter Storms” season (Dec-Jan-Feb), “Upwelling Transition” period (Mar and Jun), …


X-Ray Spectroscopy Of Nio And Nanodiamond At Ssrl, Jackson Earl Jan 2018

X-Ray Spectroscopy Of Nio And Nanodiamond At Ssrl, Jackson Earl

STAR Program Research Presentations

The first aspect of this research project focuses on investigating the surface chemistry of high pressure high temperature (HPHT) nanodiamond by using X-ray spectroscopy techniques at the Stanford Synchrotron Radiation Lightsource (SSRL). HPHT nanodiamond is being examined as a biosensing tool for electric field detection based on the fluorescent nitrogen vacancy center hosted within diamond. With use of the transition edge spectrometer (TES), a state-of-the-art X-ray fluorescence detector, we are able to probe the surface and bulk properties of diamond. Preliminary work using density functional theory (DFT) has been done, offering insight into ground state energies and electronic structure. DFT …


Resistance Temperature Detectors In A Cryostat Refrigeration System, Kirsten Marie Manahan, Alice Callen Jan 2018

Resistance Temperature Detectors In A Cryostat Refrigeration System, Kirsten Marie Manahan, Alice Callen

STAR Program Research Presentations

The Large Synoptic Survey Telescope (LSST) is a ground-based telescope that will survey the Southern sky every few nights. Located in the telescope will be a 3.2 gigapixel digital camera. To ensure proper instrumentation of the camera, there must be a monitored stable temperature. As part of my research, I assembled resistance temperature detectors and tested them to verify their reliability in measuring temperature in the camera’s cryostat refrigeration cooling system. Resistance temperature detectors function by the principle of thermal resistivity, in which their electrical resistances vary as temperature varies. Through testing, I was able to determine whether these particular …