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Evaluation of Magma Flow and Emplacement Mechanisms of the Mafic Dulce-Platoro Dike Swarm, NW New Mexico and SW Colorado Using Magnetic Susceptibility Fabrics
No full textMagnetic fabric investigations of magmatic dikes have been frequently employed for over four
decades to estimate magma flow directions to better understand volcanic and magmatic systems.
Anisotropy of magnetic susceptibility fabric data were collected from 32 sites of the
approximately 125km N-S, 25km E-W Platoro-Dulce dike swarm of late Oligocene age in
northern central New Mexico and southern central Colorado, USA, to estimate magma flow
directions. The Platoro Caldera in the Southern Rocky Mountain Volcanic Field at the northern
end of the swarm, and the incipient Rio Grande rift to the east of the swarm, represent two
potential sources for this mafic dike swarm. This study helps by considering two models of
emplacement: one involving a magma flow regime that predicts generally steep magma ascent
with no bias to horizontal component of flow or, alternatively, one that predicts generally
shallower magma ascent with a south bias to the horizontal component of flow. Rock magnetic,
paleomagnetic, and petrographic inspection of the dikes all show that the measured rock
magnetic fabric is of primary origin at time of emplacement and thus that these dikes are
permissible for estimating magma flow directions. A tentative conclusion based on inferred flow
directions which demonstrate no bias for north or south horizontal flow directions but bias for
steeply inclined vertical flow is that the Rio Grande rift likely acted the magma source and was
responsible for the extension dominated tectonic stress field in the eastern San Juan Basin that
controlled emplacement of the dikes, although the Platoro Caldera likely influenced local stress
field conditions
Pre-trained Spanish Language Model for Political Conflict and Violence
No full textExamining political conflict and violence remains a persistent challenge for the political sci-
ence and policy communities, because there comes large amount of text to be dealt with
to monitor political conflict and violence. In order to contribute to the advance of conflict
research in Spanish speaking society, we introduce ConfliBERT Spanish, a domain-specific
pre-trained language model tailored for Spanish political conflict and violence analysis. Our
method begins with the collection of a comprehensive domain-specific corpus from diverse
sources, which is then utilized for language modeling purposes. ConfliBERT Spanish is
subsequently developed using continual pre-training process. To evaluate the practical per-
formance of ConfliBERT Spanish, we assembled 5 datasets and implemented 3 tasks using
them. Through multiple experiments and evaluations on various versions of ConfliBERT
Spanish, we proved that ConfliBERT Spanish outperforms in analyzing Spanish political
conflict and violence compared to BERT baseline models
Reactions to Misconducts: Exploring Diverse Relationships
No full textIn the media, we observe different kinds of misconduct almost every day. While we may assume
that organizations conform to social norms, organizations commit misconduct. Thus, researchers
endeavor to discover its root cause. However, a dearth of research focuses on what happens after
misconduct is identified. To fill in this research gap, this dissertation contributes to
organizational misconduct by highlighting reactions after misconduct. Specifically, we
investigate diverse relationships surrounding misconduct. There are three essays that explore the
reaction to misconduct by applying the proper theoretical lens.
The first essay (Chapter 1), which was accepted and published online first by Business and
Politics, dives into the dynamic between the culpable organization and bystanders. Specifically,
we highlight the reaction of the shareholders at bystanders to witnesses of the misconduct and
discuss the resolution. Among various types of misconduct, we choose the corrupted corporate
political activity of lobbying. One of the most corrupted lobbying scandals in U.S. history, the
Jack Abramoff case, has drawn considerable attention. The negative impact of the lobbying
scandal pushes the boundaries of the impact on the bystanders. We explore the reaction of
shareholders of bystanders to the guilty plea of Abramoff and the introduction of the new
lobbying law. By using expectancy violation and category theory, we argue shareholders at
bystanders show hostile responses to the corrupted lobbying scandal while favoring the new
lobbying act. To show the generalizability of our arguments, we reference the Enron scandal and
the introduction of the Sarbanes-Oxley act.
The second and third essays leverage workplace injuries as a form of misconduct. The second
essay (Chapter 2) uses workplace injuries to investigate the tense relationship between peers and
the focal organization. This essay asks this research question: Does the focal organization react
to peers’ workplace injuries? A theoretical lens from social comparison and impression
management provides an insightful explanation to this question by arguing that peers’ workplace
injuries trigger fear among the employees at the focal organizations, leading to the focal
organizations’ responses: engagement in impression management is used to distinguish
themselves from peers. This goal can be achieved through social comparison by their employees.
The third essay (Chapter 3) narrowly focuses on the organization itself. Unlike the other two
essays, the third essay investigates the reaction to the misconduct that occurred by the
organization. Leveraging the fact that organizations are reluctant to invest in the prevention of
workplace injuries, we ask: What makes the organization invest in the prevention of workplace
injuries? Borrowing the theoretical views from optimism bias and the attention-bias view, we
argue that optimism bias among top managers breaks down when workplaces experience direct
loss. The breakdown of optimism bias attracts attention to injury and succeeds in deploying more
resources
Using Seismic Ambient Noise to Monitor Environmental Changes
No full textOver the past decades, the Earth has suffered from a variety of environmental hazards,
such as global warming, floods, drought, ice sheets melting and sea level rise. Scientists
would like to monitor, interpret and predict these hazards by using different techniques.
As a seismologist, I would like to generalize seismological techniques and apply them to
explore these severe hazards. One of my research directions is to measure near-surface
seismic velocity changes (dv/v) from ambient noise records, and then correlate them with
independent environmental variables. The first topic is to measure decadal dv/v by auto-
correlating noise records at each seismographic station deployed in Greenland. Our results
demonstrate that dv/v for most stations have less than 3 months lag times in comparison
to the surface ice mass change. These various lag times may provide us with constraints
for the thickness of the subglacial till layer over different regions in Greenland. Moreover,
we also observe a change in the long-term trend of dv/v in southwest Greenland, which is
consistent with the mass change rate during the “2012-2013 warm-cold transition”. The
second topic is to explore the potential of using regional averaged dv/v records to predict
incoming flood events in the Yellowstone National Park (YNP). Over the past ten years,
we find that the annual peaks of dv/v variations always have one to two months lead-time
in comparison to anomalous water discharges in summers. In particular, there was a short-
term high velocity perturbation around 62 days ahead of the 2022 historic flood in the YNP.
We therefore suggest that the annual peaks of dv/v in springs are mainly driven by snow
accumulation during winters, which might be the major contributor to the flood events in
the YNP. This study demonstrates the potential of using seismic observables to predict
incoming flood events one to two months in advance. The third topic is to use machine
learning (convolutional neural networks) to build a complete aftershock catalog for the 2020
MW 6.5 Stanley, Idaho earthquake. This new catalog has over seven times more events and
0.9 lower completeness magnitude than the current USGS-NEIC catalog. The distribution
and expansion of these aftershocks improve the resolution of two north-northwest-trending
faults with different dip angles, providing us further support for a central stepover region
that changed the earthquake rupture trajectory and induced sustained seismicity
The Expanded Role of the Business Press Following Auditor Reputation Damage
No full textThis paper examines whether auditor reputation loss affects the interplay between a firm’s auditor
and the business press. Exploiting the Arthur Andersen scandal as a quasi-natural experiment, I
find that the media increased its coverage of Andersen’s clients following Andersen’s reputation
loss and that the heightened negative coverage is informative of future restatements. These
findings suggest that the media fulfills an expanded monitoring role of firms’ financial reporting
following reputational damage to the firm’s auditor. Additional analyses corroborate the notion of
the media expanding its monitoring of AA firms’ financial reporting and that the greater coverage
is incrementally informative to investors. Overall, my study provides new evidence of the
interaction between a firm’s auditor and the monitoring role of the business press
Effects of Aluminum Plate Residual Stress on Machined-part Distortion
No full textDimensional tolerance requirements for high-speed-machined aluminum products continue to
tighten due to strong demand for automated assembly of complex monolithic aluminum parts in
aerospace and other industries. Understanding the contribution of inherent residual stress in
wrought aluminum 7050-T7451 plate, a common alloy in aircraft manufacture, in the distortion
of high-aspect-ratio machined monolithic parts is critical but remains problematic. The difficulty
stems from the alloy’s low magnitude of residual stress, distributed over relatively large
geometries. The numerous prior studies aimed at investigating residual stress effects on
machined part distortion, however, suffer from inadequate characterization of the inherent stress
field within the wrought material—because of low fidelity issues due to slitting methods of
residual stress measurement, confounding effects from machined-layer removal methods, or
because of small number of measurements when using neutron diffraction (ND). In this work,
inherent residual stress is measured using ND at over 860 locations throughout the volume of a
90.5 mm thick 7050-T7454 aluminum plate having dimensions 399 mm in the longitudinal
(rolling) direction and 335 mm in the transverse direction. Unlike prior studies, the ND residual
stress field is reconstructed using an iterative stress reconstruction algorithm to ensure a fully
compatible and equilibrated 3D field prior to examining its effect on the distortion of a high-
aspect-ratio monolithic part. Validation of the equilibrated stress field is accomplished by
comparison of corresponding aggregate fields generated by both experimental and simulated
slitting techniques. To isolate and study the potential contribution of residual stress on part
distortion, an element deletion technique to simulate material removal is performed to avoid
confounding with any machining-induced effects. The findings reveal that the inherent residual
stress is not negligible, and alone is sufficient to distort a high-aspect-ratio part beyond
tolerances necessary to meet current aerospace industry manufacturing requirements (>0.75 mm
distortion over 400 mm span). Moreover, the work reveals that a residual stress field developed
only from slitting data, per the literature, underrepresents both residual stress and part distortion.
The results show that parts created from different locations within the plate thickness can lead to
reversed distortion patterns due to the corresponding residual stress induced effects. The
research gives insight into fixturing and shimming to compensate for distortion as well as
provides an algorithm to further address distortion of the finished part by applying weights to in
accordance with industry practices
A Day in the Life: Kkandbabyj, An Exploration of Three-Dimensional Design Processes to Convey Character Dynamics
No full textA Day in the Life: Kkandbabyj, An Exploration of Three-Dimensional Design Processes to
Convey Character Dynamics is a sixteen-month Master’s Thesis project in which the artist
explores the complex processes of 3D modeling and examines how a family of social media
influencers’ image can be translated from the real world to 2D design, and result in stylized 3D
characters that demonstrate a dynamic story between character models. This paper is designed to
introduce readers to the three-dimensional design process and demonstrate one method in which
storytelling can be told in a virtual space using a variety of techniques to imply motion with
static digital figures. While this paper describes a detailed artistic methodology custom to the
author’s workflow and creativity, it will not disclose the specifics of the digital software or tools
without relevance to the overall storytelling agenda. The process of this thesis includes an
analysis of preproduction, understanding shape language, setting dynamic poses through rigging
techniques, creating atmosphere with texture and lighting, and using cinematography in a way
that best strengthens the overall story
Pyrrole Based Donor-acceptor Building Blocks for Organic Field-effect Transistors
No full textThe class of organic semiconductors is a definite contender for replacing high-cost silicon
semiconductors owing to unique advantages such as solution processability, flexibility,
lightweight, low cost, and the ability to do multiple structural modifications. Hence, a remarkable
amount of scientific research has been carried out to improve the electronic properties of these
materials. Throughout the past two decades, many improvements in the field have achieved by
designing novel building blocks. There remains the possibility, however, for performance
improvement through areas that has paid less attention in both conventional and non-conventional
building blocks. Because of the appealing performance of organic semiconductors, it is highly
desirable to seek and develop new building blocks for the next generation of organic electronics.
In this dissertation, the fundamentals, history, and recent developments of conventional and nonconventional materials are covered briefly in the first chapter. Operation principles, charge
transport of organic field effect transistors is introduced. Compared to conventional thiophenebased -electron donor materials, promising non-conventional pyrrole-based donor materials
employed in organic field effect transistors are discussed and summarized. Chapter 2 describes the
effect on organic field effect transistor (OFET) properties of a donor-acceptor polymer consist of
a branched ester functionalized bithiophene copolymerized with thiophene vinyl thiophene donor.
The influence on frontier molecular orbital energy levels, UV-vis absorption, electrochemical
properties, OFET parameters and morphological effects were investigated. In chapter 3, the effect
of furan spacer group on a thieno[3,2-b]pyrrole and diketopyrrolopyrrole based copolymer is
discussed. Upon changing similar flanking groups, the polymer showed a high hole mobility of
0.42 cm2
/V s while the on-to-off ratio exhibited a drastic improvement 105
. Chapter 4 describes
the incorporation of selenium hetero atom in the pyrrole fused rings to yield seleno[3,2-b]pyrrole
based small molecules replacing thieno[3,2-b]pyrrole to extend the knowledge of OFETs activity
of seleno[3,2-b]pyrrole in banana shaped small molecules. They exhibited moderate charge carrier
properties 10-2
cm2
/V s hole mobility.
In the Chapter 5 (attached as an appendix), a study on oxidative degradation of polypropylene
mesh in Escherichia coli (E. coli.) environment is disscussed. Medical implants of polypropylene
(PP) mesh have demonstrated biodegradation inside the body. Among the many possible factors,
bacterial colonization is believed to be one of the causes for biodegradation. To gain insights on
this hypothesis PP mesh samples were tested in Luria-Bertani broth containing E. coli and the
experimental results demonstrated qualitative and quantitative bioerosion, confirming the
oxidative degradation in vitro
Inter-turn Short Circuit Fault Detection in Permanent Magnet Synchronous Motors Through Machine Parameter Identification
No full textAC motors, specifically Permanent Magnet Synchronous Motors (PMSM) have been gaining
popularity in industrial applications due to their high efficiency, high power density and high
torque generation capabilities. Apart from industrial applications, the market share of these motors
has seen significantly increasing use in emerging technologies such as Electric vehicles (EVs),
Hybrid Electric Vehicles (HEVs) as traction motors, and use in electric ships, and electric
airplanes. To ensure safety and reliability of operation in safety critical applications, continuous
health condition monitoring and fault diagnosis of these motors is essential. A robust and accurate
fault diagnosis and condition monitoring reduces downtime and unplanned catastrophic failures,
shutdowns, and maintenance, which saves both time, money, and labor. Through the available
drive sensors such as current and voltage sensors, current and voltage information can be acquired
and used to diagnose different faults in the motor. This dissertation presents condition monitoring
of stator Inter-Turn Short Circuit (ITSC) faults in PMSM motors.
ITSC faults make up more than 40% of all PMSM electrical faults, mainly caused by extreme
mechanical, thermal, and electrical stresses. Other factors such as high dv/dt and chemicals
accelerate insulation material aging and result in ITSC faults. ITSC fault causes high circulating
currents to be induced in the stator of the motors, and if not properly managed, can result in local
overheating which leads to further winding degradation and melting, which can result in complete
shutdown of the machines operation. Thus, to avoid unexpected machine shutdowns, ITSC fault
must be monitored, diagnosed, and managed.
This dissertation employs continuous monitoring of machines electrical parameters such as the
stator resistance (Rs) and both d-axis and q-axis inductances (Ld and Lq) to detect any changes
which may be a result of ITSC faults. Upon detecting changes in parameters, ITSC fault is
diagnosed by isolating it from other closely similar faults such as eccentricity faults.
The techniques employed in this dissertation eliminates the use of extra sensors in the drive, and
only uses current sensors to acquire feedbacks, and uses voltages inside the micro-controller to
estimate different parameters for diagnosis purposes
Structural Design and Optimization of Sub-scale and Extreme-scale Wind Turbine Rotors
No full textThe main objectives of this dissertation are to develop some new design and optimization
solutions for large/extreme-scale (up to 50 MW) wind turbine rotors, as well as a structural
design method for a sub-scale wind turbine blade for manufacturing and field testing. To
accomplish these objectives, a series of 13.2 MW downwind rotors is designed and optimized.
A key question to enable large rotor designs is how to configure and optimize structural designs to constrain blade mass and cost while satisfying a growing set of challenging structural
design requirements. In this dissertation, the performance of a series of three two-bladed
downwind rotors with different blade lengths (104.3 meters, 122.9 meters, and 143.4 meters)
all rated at 13.2 MW is investigated. The primary goals are to achieve 25% rotor mass and
25% LCOE (levelized cost of energy) reduction. A comparative analysis of the structural
performance and economics of this family rotors is presented. To further explore optimization opportunities for large rotors, the new results in a root optimization and a spar cap
design study are presented. The structural design solutions that achieve 25% rotor mass
reduction in a SUMR13i design (104.3 meters) and 25% LCOE reduction in a SUMR13C
design (143.4 meters) are provided.
A new sub-scale field-prototype design solution is also developed to realize the dynamics,
structural response, and distributed loads (gravitational, aerodynamic, centrifugal) that are characteristics of a full-scale large, modern wind turbine rotor. The challenge lies in producing a structural design meeting two competing objectives: novel scaling objectives that
prescribe the sub-scale blade to have low mass and stiffness; and traditional structural safety
objectives that drive the design to have high stiffness and mass. A 20% gravo-aeroelastically
scaled wind turbine blade is developed successfully that satisfies these competing objectives.
First, it achieves close agreements for non-dimensional tip deflection and flap-wise blade
frequency (both within 2.1% error) with a blade mass distribution constrained to produce
target gravitational and centrifugal loads. Second, the entire blade structure is optimized
to ensure a safe, manufacturable solution meeting strict strength requirements for a testing
site that can experience up to 45 m/s wind gusts.
Next, 50 MW wind turbine rotors with blades’ length over 250 meters are designed and optimized. Key questions in this work include: what is the structural limit for the size of a wind
turbine rotor to be feasible or cost-effective, and what are the technologies and approaches
needed to achieve large rotors. The largest wind turbine design in prior work is a 25 MW
rotor, and here a 50 MW rotor design is considered, the largest ever design with blades’
length over 250 meters, which is 2.5 times the length of a football field. This dissertation
shows that a 50 MW design is indeed possible from a detailed engineering perspective and
presents a series of aero-structural blade designs for 50 MW wind turbine rotors, and a critical assessment of technology pathways and challenges for such extreme-scale rotors. The
rotor design for the 50 MW rotor begins with Monte Carlo simulations focused on optimizing
the carbon spar cap design, which is found to be a major cost driver in the blade design.
Further, a study of blade root fatigue performance is performed, which is found to be the key
limitation for the extreme-scale machine at 50 MW scale. A baseline, initial design results in
a 250-meter blade with a mass of 500 metric tons. This initial study indicates a significant
opportunity for improvement through the aero-structural design; thus, an aero-structural design and optimization study is performed to reduce the blade mass/cost and achieves more mass/cost-effective 50 MW rotors that result in more than 25% mass reduction and over
30% cost reduction by determining the optimal blade chord and the optimal airfoil thickness
for the best aerodynamic and structural performance.
Wind turbine blade reliability is critical once blades go into service in operation to avoid
costly repairs and lost revenue due to turbine downtime resulting from blade damage. With
increased size of the blade, especially for the extreme-scale blades, the blade can experience
a more complicated loading. A new method utilizing the panel behavior for structural
health monitoring and nondestructive damage detection is examined in this dissertation. The
localized panel resonance (panel mode) is identified by the experimental modal test of the
BSDS blades at Sandia National Laboratories and numerical analysis of an open-source BSDS
design model. Then the study is extended to a larger, novel concept SUMR-D blade design,
which was presented in Chapter 3. Some classical wind turbine damage modes are simulated
based on the SUMR-D ANSYS model, including shear webs disbonding simulations and
trailing edge disbonding simulations. A relation is established to correlate the panel mode
with the damage size, which can be applied to structural health monitoring applications.
For the shear webs damage cases, a relation is established to correlate the panel mode with
panel buckling performance as a function of damage size based on numerical results and
analytical formulae, which has potential applications in the nondestructive buckling capacity
evaluation