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Beyond Victimhood: An Analysis of Rape Culture Rhetoric on Sexual Assault Survivors
No full textThis thesis delves into pivotal moments and movements within recent cultural histories of sexual assault, focusing on Chanel Miller's rape by Brock Turner and the evolution of Tarana Burke's "me too" movement into #MeToo. Through an analysis of media coverage and literary works such as Miller's memoir, Know My Name, and Jodi Kantor and Megan Twohey's, She Said, this study explores the embedded dynamics of rape culture and sexual assault tolerance within American society and institutions. Emphasizing survivors' voices, this research contends that their narratives are vital in challenging societal perceptions and fostering empathy towards survivors. Drawing on insights of fellow feminist scholars, this thesis investigates the role of survivors in dismantling patriarchal structures that perpetuate rape and sexual assault. Methodologically, this thesis examines the concepts of the good survivor, ideal victim, and naming and shaming, dissecting the societal frameworks that influence survivors' reporting behaviors and perceptions. By scrutinizing government-funded programs' methodologies and limitations in gathering accurate statistics on sexual violence, the research underscores the complexities and challenges in understanding the prevalence of rape and sexual assault. Ultimately, this work advocates for a nuanced understanding of survivor experiences and calls for a societal shift towards empathy and support for survivors, challenging entrenched rape culture mentalities
Role of Ventral Hippocampus in the Contextual Control of Avoidance
No full textAnimals react to aversive situations with a complex set of behaviors that reduce the likelihood of predation. Of course, animals have the capacity to learn from their experience; this allows them to anticipate and defend against future threats. On the one hand, Pavlovian conditioned responses, such as freezing behavior in rats, adaptively generalize to a variety of threats and environments in which they might be encountered. On the other hand, instrumental learning, such as making an active escape or avoidance response to avoid a painful event, enables animals to develop new behavioral strategies to avoid future threats. Compared to their Pavlovian counterparts, the neural and behavioral mechanisms of instrumental avoidance responses are poorly understood. In particular, whether avoidance responses exhibit a tendency to generalize across many contexts is unknown. To address this question, I assessed the context-dependence of instrumental avoidance learning in male and female rats. These studies used a two-way signaled active avoidance (SAA) task, in which animals can avoid an aversive footshock by shuttling in response to a warning signal. In the first set of experiments, I determined whether a learned avoidance response transfers to a new context and whether the contextual control of avoidance requires the hippocampus, a brain area that has been implicated in this form of learning. This work revealed that shuttle-box avoidance was context-dependent and decreased outside of the training context; inactivation of the ventral (VH), but not dorsal (DH) hippocampus, with the GABAA agonist, muscimol, eliminated the context-dependence of the response. In another set of experiments, I examined avoidance responses to the training context itself���so called inter-trial responses (ITRs). Inactivation of the VH decreased ITRs, whereas chemogenetic activation of the VH with ���designer receptors exclusively activated by designer drugs��� dramatically increased the number of ITRs. Together, these studies reveal that the VH has a role in both determining the context in which a threat-induced avoidance response is emitted and in promoting ITRs in the aversive context itself. The neural circuits by which the VH mediates these two functions of context in avoidance requires further investigation
Development of a Finite Element Analysis (FEA) Model for Predicting Elbow Torque of the Apollo A7LB Extravehicular Activity (EVA) Spacesuit Pressurized Sleeve
No full textEVA spacesuits are critical to human survivability in the hostile environment of space, which consists of low atmospheric pressures (e.g., vacuum in LEO and on the lunar surface) and temperature extremes (e.g., ���65��C to 125��C in LEO). While spacesuits must protect humans against these conditions, maintaining an astronaut���s mobility is also crucial to achieve mission objectives such as in a return to the Moon as defined by the Artemis architectures. Spacesuit mobility is largely driven by the design of joints such as in the knees, shoulders, ankles, waist, and elbows. In the Apollo A7L/A7LB spacesuits, full circumferential rubber-dipped nylon convolutes were utilized in these joint locations. Understanding the Apollo elbow joint design���s mobility, in comparison to the Extravehicular Mobility Unit���s (EMU) flat pattern gore design, could provide new insights for the development of future spacesuits. In this research, an Abaqus FEA model was developed to predict elbow joint torques during pressurized bends using the A7L/A7LB pressure garment assembly arm configuration. The model was scripted to allow for simple adjustment of numerous design variables, such as the number and size of the convolutes. Through DOE studies, it was found that sleeve radius had the largest proportional effect on joint torque, while sleeve thickness and fabric bias direction Young���s modulus had smaller effects. Increasing number of convolutes reduced joint torque, but this effect diminished at larger numbers. Increasing operating pressure significantly increased joint torque, especially at high bend angles (such as 120 degrees). The results showed that lowest torque designs from these DOE studies required less joint torque than an Aerospace Human Systems Laboratory (AHSL) EMU FEA elbow model up to 55-60 degrees, and after 105 degrees. The model was also adjusted to available Apollo sleeve dimensions, and the material properties were approximated to yield joint torque data closely aligned with an A7LB empirical measurement in literature. Results showed this Apollo sleeve required less joint torque than the AHSL EMU model from 0-40 degrees. Lastly, the model was adjusted to an alternative convolute joint used in empirical joint testing, and joint torque results were the same order of magnitude as reported data
Fracture Strength of 3D Printed Resin Interim Fixed Partial Dentures Varying Connector Sizes
No full textThe aim of this in vitro study is to determine the minimum connector size for 3-unit FPD���s comparing two different types of 3D printed resin to zirconia. A mandibular typodont quadrant was prepared for first premolar and molar all ceramic crowns with 0.5mm chamfer margins and total 6-degree convergence angle. The model was scanned via intraoral scanner (3Shape, Trios 4) and uploaded into CAD software (Exocad). 3-unit FPD with various connector sizes 9mm^2, 12mm^2, and 16mm^2 were designed. 3D printed two resins (OnX and Dentca C&B) with SprintRay Pro55. After the prints are completed, the interim FPDs were removed from the build plate, cleaned, and cured using manufacturer recommendations. FPDs were printed at a 0 degree build angle with 100��m layer thickness. 15 samples were printed per test group (N=90). Control group comparison made with a milled 3Y-zirconia 9mm^2 group (n=15). Fracture load tested with Instron machine with vertical pressure applied through pontic site at 1mm/min. FPDs placed onto typodont abutments and mounted on Instron machine. Failure was defined as the moment when the load dropped by 10% under the maximum value. The force (in Newtons) was recorded at the time of failure. Statistical analysis was completed using SPSS software to analyze the differences between the groups. Results were normally distributed, so one-way ANOVA was performed. Descriptive statistics will be added based on the location of fracture, and type of fracture. OnX had significantly higher maximum force at fracture (1236��135N) than Dentca C&B (884��136N, p<.001) and zirconia (456��87N; p<.001). Connector size had a significant difference for OnX for all sizes (p<.001), while significance for Dentca was only between 9 mm^2 and 16mm^2 (p=.006). The resins shattered upon failure, whereas zirconia simply split. Connector size and material type played significant roles in fracture resistance, with both resins withstanding significantly more force than typically generated during chewing
A Multifaceted Investigation of Cloud Microphysics: From Improving Convective Cloud Microphysics Parameterizations to Revealing Aerosol-Cirrus Cloud Interactions
No full textCloud microphysical processes and their parameterizations are at the core of multi-scale atmospheric modeling but still remain one of the major sources of uncertainty in weather and climate simulations. The aims of this dissertation are twofold: advancing our understanding of the physical processes involved in aerosol-cloud interactions and developing new parameterizations for better representing cloud microphysics in global climate models (GCMs). This dissertation is divided into two main parts. Part I focuses on evaluating and improving cloud microphysics parameterizations for convective clouds in GCMs. Part II focuses on investigating the impacts of volcanic aerosol on cirrus cloud using satellite observations, detailed microphysical model simulations and two GCMs.
GCMs have started treating convective clouds with detailed cloud microphysics parameterizations. However, the representations of convective cloud microphysical processes are often based on those for large-scale stratiform clouds, warranting further model evaluation for the fidelity of microphysics treatments transferred among various cloud types. Here, we evaluate and improve several aspects of the convective cloud microphysics in the NCAR Community Atmosphere Model version 5.3 (CAM5.3), including processes of hydrometeor sedimentation, graupel production, convective snow detrainment, and rain generation against ground-based and satellite observations. Our model development efforts lead to substantial improvements in the simulations of cloud radiative forcing, graupel microphysics, convective cloud ice amount, and tropical precipitation over the default model settings. These improvements set a better stage for future studies of convective cloud processes and their interactions with large-scale environments and aerosols.
Explosive volcanic eruptions inject a large amount of sulfur dioxide and ash particles into the upper troposphere and lower stratosphere, where volcanic-origin aerosols (sulfate and ashes) may modify cirrus cloud microphysics through ice nucleation but to an unknown extent due to limited research on this topic. Here, we aim to narrow this knowledge gap with the advent of advanced satellite retrievals of aerosol and cloud capturing the episodes of enhanced stratospheric aerosol loadings produced by modern moderate-magnitude eruptions. An analysis of 10-yr satellite datasets shows a phenomenal decrease in number and increase in size of cirrus ice crystals in the midlatitude lower stratosphere in response to ash-rich volcanic eruptions (2008 Kasatochi, 2009 Sarychev), indicative of heterogeneous freezing on volcanic ash suppressing homogeneous freezing. Conversely, cirrus clouds for the ash-deficit scenario (2015 Calbuco) are found to have up to 2.2 times more ice crystals, implying a moderately enhanced homogeneous freezing on volcanic sulfate aerosols. These impacts of aerosol on cirrus cloud, disentangling influences from meteorological co-variability, are most likely. Cloud parcel model with detailed physical ice nucleation processes is employed to elucidate the mechanisms of aerosol effects and the modeling results corroborate the observational findings. Sensitivity modeling experiments are also performed using two GCMs, CESM2.2 and E3SM-PA. Impacts of sub-grid scale vertical velocity generated by gravity waves on cirrus ice formation and volcanic ash emissions are found absent, identifying models��� inability to accurately capture the response of cirrus clouds to volcanic emissions and areas for future model development.
The studies in this dissertation advance our understanding of volcanic aerosol-cirrus cloud interactions on the process-level, stress the necessity and importance of accurate representations of cloud microphysical processes in GCMs, and advocate iterative effort in improving parameterizations as GCMs are the only means by which we project future climate
General Sizing Relationships for Axial Flux Motors
No full textThis dissertation presents a comprehensive study of the design, optimization, and performance analysis of axial flux motors, focusing on enhancing their performance potential using a multiphysics design approach of the motor���s shared electromagnetic, thermal, and structural geometry. Axial flux motors are known for their compact structure and high power density and are increasingly becoming an item of interest for applications such as aerospace and other traction applications.
The contemporary fractured design process substantially slows novel motor design, with each subsystem designed and optimized separately. A significant contribution of this research is the development of a set of simultaneous performance scaling relationships for axial flux motors, providing a valuable tool for designers to predict motor behavior based on key geometric and system-level parameters in the early stages of design. The resulting method can estimate equivalent finite element results within 8.8% across the range of interest in approximately 1/650th the time, with a maximum error of 16.6%. The final result validation is provided via comparison with commercially available high-performance motors as well as published results relating cooling topology with current density.
The dissertation concludes with a discussion of the potential impacts of the study on the future development of axial flux motors, highlighting the opportunities for further research. This work not only advances the state-of-the-art in axial flux motor technology but also contributes to the broader field of electric machinery by providing valuable insight into how the design of electric machines can be improved to reflect the computational tools available to modern engineers
Synthesis and Evaluation of Tribological Performance of Mxenes
No full textThis work addresses the challenges associated with the synthesis of MXene (acid etching) using an alternative method of molten salt etching and alteration of interfacial properties. This thesis is part of a thrust to develop acid free synthesis of MXenes at an industrial scale.
The initial part of the thesis is focused on the acid-free synthesis of MXenes via molten salt etching. Despite numerous prior reports of molten salt etching of MAX phases, few of these reports achieved water-dispersible MXene nanosheets and none for Nb-based MXenes. Here, we demonstrate the synthesis and aqueous dispersibility of Nb2CTz nanosheets via molten salt etching and utilizing a KOH wash to add hydroxyl surface groups. However, little is known about the oxidation of molten salt-etched MXenes compared to acid-etched MXenes. This work has indicated the slower oxidation behavior for MXenes etched by molten salts, which may be due to the decreased amount of oxygen-containing terminal groups.
A significant portion of my thesis is focused on utilizing the MXene (acid etched and salt etched) for tribological applications as liquid or solid lubricants. Owing to the high thermal conductivity, electrical conductivity, and mechanical strength of Ti3C2Tz nanosheets, they seem to be a promising candidate as lubricant additives. In this work, we evaluate the performance of Ti3C2Tz as an additive to enhance the heat transfer, rheological properties, and tribological performance of oils. The improved properties (Thermal conductivity) and reduced fluidic drag in viscosity and friction lead to potential applications in (electrical) vehicles that will help attain improved fuel economy.
Although surface terminations (such as ���O, ���Cl, ���F, and ���OH) on MXene nanosheets strongly influence their functional properties, synthesis of MXenes with desired types and distribution of those terminations is still challenging. In my thesis, we demonstrated that thermal annealing helps remove much of the terminal groups of molten salt-etched multilayered (ML) Ti3C2Tz. In this work, the chloride terminations of molten salt-etched ML-Ti3C2Tz were removed via thermal annealing. This thermal annealing created some bare sites of high surface energy and reactivity that are available for further functionalization of Ti3C2Tz. Here, the annealed ML-Ti3C2Tz was re-functionalized by ���OH groups and 3-aminopropyl triethoxysilane (APTES)z, which were evaluated as a solid lubricant, exhibiting ���70.1 and 66.7% reduction in friction compared to a steel substrate, respectively. This enhanced performance is attributed to the improved interaction or adhesion of functionalized ML-Ti3C2Tz with the substrate material. This approach allows for the effective surface modification of MXenes and control of their functional properties.
The ability to control the d spacing of MXene has proved beneficial for energy storage applications such as batteries and supercapacitors, but no one has utilized this control of interlayer spacing for lubrication. In this work, we control the interlayer spacing between the ML-Ti3C2Tz MXene via chemical intercalation. In order to alter the d-spacing, we investigated several different-sized intercalating agents. The increase in the d-spacing of ML-Ti3C2TZ MXene resulted in a drop in electrical conductivity and friction coefficient. Specifically, the enlarged interlayer gap reduced electrical conductivity in the vacuum-filtered ML-Ti3C2Tz MXene films due to increased internal resistance. Additionally, the increased d-spacing or interlayer spacing of ML-Ti3C2Tz resulted in a reduction of the coefficient of friction. This decrease is attributed to the facilitated sliding of individual ML-Ti3C2Tz layers under applied shear forces or load, resulting from the weakened van der Waals interactions due to the increased interlayer spacing
Modulating the Tumor Microenvironment via Plga-Mno2 Nanoparticle Mediated Hypoxia Reduction Leads to Increased Immune Responses Against Bone Metastases
No full textBone metastases result in a stark decrease in survivability in cancer cases, with most treatment options focusing on palliative care. Newer therapies, such as immunotherapies, use the patient���s immune cells to target tumors, sometimes to great effect. Though immunotherapies have been effective against some advanced-stage tumors, there has been limited success with bone metastases. Persistent hypoxia in the bone, necessary to maintain the hematopoietic stem cells, induces an immunosuppressive microenvironment that blunts the activity of cytotoxic immune cells against bone metastases. To address this, we have developed a nanoparticle capable of modulating the bone metastasis microenvironment to improve the antitumoral immune response. In this study, we use manganese dioxide nanoparticles (MnO2 NP) to catalyze the degradation of tumor-produced hydrogen peroxide, thereby generating oxygen. For improved biocompatibility and modulation of oxygen production, the MnO2 NPs were encapsulated into poly lactic-co-glycolic acid (PLGA-MnO2 NPs) to produce particles provide sustained high oxygen tension. The PLGA-MnO2 NPs were biocompatible, reduced hypoxia after penetration into the core of cancer spheroids, and decreased hypoxia-induced factor 1 alpha expression. Reducing hypoxia in the spheroid resulted in a decrease in adenosine, and lactate, immunosuppressive metabolites. Notably, the spheroids��� microenvironment changes enhanced NK cells' cytotoxicity, which obliterated the spheroids. Then, to address chronic hypoxia, we then developed altered the PLGA formulation to create poly lactic(50)-co-glycolic(50) (50:50 PLGA), poly lactic(75)-co-glycolic(25) (75:25 PLGA) and poly lactic acid (PLA) encapsulated MnO2 NPs. We then analyzed the oxygen kinetics due to each polymer type and showed that the 50:50 PLGA-MnO2 NPs exhibited the best short- and long-term control of hypoxia in cancer spheroids and the PLA-MnO2 NPs possessing the slowest O2 generation kinetics. In vivo, the 50:50 PLGA-MnO2 showed greater accumulation in the long bones and pelvis, common sites for bone metastases. The NPs decreased hypoxia in bone metastases and decreased regulatory T cell levels, resulting in enhanced survival of mice with established bone metastases
Improving the SPEE Monograph 3 Approach through MLR-Normalization
No full textIn 2008, as part of a modernization effort, the Securities and Exchange Commission (SEC) adopted rules restricting undeveloped reserves to acreage directly offsetting existing wells unless reliable technology could justify greater distances. This rule significantly limited the amount of proved undeveloped (PUD) reserves that could be disclosed in unconventional plays, which require more wells to fully develop than their conventional counterparts. Recognizing the industry's need, the Society of Petroleum Evaluation Engineers (SPEE) published its third monograph in 2010.
The SPEE Monograph 3, while innovative, limited its calculations to estimated ultimate recovery (EUR) normalized by completed lateral length (CLL). It otherwise overlooks other operator-controlled variables, such as completion design, location and well depth, which are shown to have a significant impact on performance.
In the following thesis, I augment the SPEE Monograph 3 approach with multiple linear regression (MLR) models using certain operator-controlled variables from publicly available sources. I generate an equation to explain additional variability in performance and normalize EURs. Finally, I follow the SPEE Monograph 3 recommendations for estimating proved areas and volumes, comparing the results to CLL-normalization alone.
In the Woodford case study, my proposed workflow was shown to reduce minimum analogs required for the initial establishment of reliable technology by 27%, resulting in the booking of PUDs beyond direct offsets 18 months sooner. Additionally, the use of MLR-normalization resulted in proved areas up to 15% larger and proved volumes up to 31% larger than CLL-normalization.
Modern software and data availability make MLR models achievable for operators of all sizes. My work utilized RStudio, a free programming software with many statistical packages, and Enverus, an online subscription service to oil and gas data. With some effort, MLR modeling is programmable, making it easy to integrate into existing PUD workflows
Free-Form Dithering
No full textIn this paper, we will present free-form dithering, a function-based dithering parallel dithering framework. The free-form dithering framework is appropriate to use in real-time applications it is straightforward to implement its parallel algorithms with GPU-based shader languages. This framework is implicit based on the sense that we construct hatching curves by altering the shapes of hatching curves using isocurves that are defined by type distance functions. Using distance functions allows us to precisely control the frequency of isocurves