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Full-Text Articles in Physical Sciences and Mathematics

Response Of Soil Biochemical And Physical Properties To Long Term Prairie Cordgrass And Kura Clover Intercropping System, Vaishnavi Varikuti Jan 2022

Response Of Soil Biochemical And Physical Properties To Long Term Prairie Cordgrass And Kura Clover Intercropping System, Vaishnavi Varikuti

Electronic Theses and Dissertations

Prairie cordgrass (Spartina pectinata) (PCG) is a warm-season perennial grass that can be used as a biofuel feedstock and can be grown on marginal lands. Previous studies on intercropping of a perennial legume i.e., kura clover (Trifolium ambiguum) (KC) with PCG can improve soil biochemical properties, increase biomass production, mitigate greenhouse gas (GHG) emissions while reducing the chemical fertilizer requirement. However, there is a lack of evidence about the effects of PCG production on soil biochemical and physical properties during the cropping season and at deeper soil depths in reference to support plant growth, environmental implications and enhance the soil …


Using Deep Neural Networks To Analyze Precision Agriculture Data, Stephanie Liebl Jan 2022

Using Deep Neural Networks To Analyze Precision Agriculture Data, Stephanie Liebl

Electronic Theses and Dissertations

As the population of the Earth increases, there is a growing need for food to feed the inhabitants. Precision agriculture offers techniques and tools that can be used to help accommodate the growing population. One specific precision agriculture tool is remote sensing data, which can be used to image fields as an effort to better predict or understand the crops. In this thesis, deep neural networks are used to evaluate various spatial, spectral, and temporal resolutions of three different satellite images to determine which best predicts corn yield. The main metrics we used to evaluate the models were R-squared (R2), …


The Significance Of A New 11,000-Year Volcanic Record From The South Pole And Inferences From Comparisons With Other Volcanic Records, Derek Lee Brandis Jan 2022

The Significance Of A New 11,000-Year Volcanic Record From The South Pole And Inferences From Comparisons With Other Volcanic Records, Derek Lee Brandis

Electronic Theses and Dissertations

Snow accumulation at the polar regions of the planet preserves chemical substances from the atmosphere creating natural archives. Records of the atmospheric environment including atmospheric chemical composition and the climate can be reconstructed from ice cores from the polar ice sheets. Sulfur emitted by explosive volcanic eruptions is preserved as sulfate in polar snow and can be used to reconstruct the record of volcanic eruptions. Since large volcanic eruptions impact the environment and climate, records of volcanic eruptions from ice cores can help us to study and understand climate change and model the future climate environment. A 1750-m ice core …


Eastern Redcedar (Juniperus Virginiana L.) Encroachment On South-Central South Dakota Rangelands: Impact On Plant Communities, Austin K. Domeier Jan 2022

Eastern Redcedar (Juniperus Virginiana L.) Encroachment On South-Central South Dakota Rangelands: Impact On Plant Communities, Austin K. Domeier

Electronic Theses and Dissertations

Grasslands historically covered 46 million km2 of Earth’s surface representing nearly 42% of the living vegetation. Encroachment of woody species onto grasslands and savannas is a widely researched global phenomenon, with eastern redcedar (ERC) (Juniperus virginiana L.) trees being the most prominent woody encroacher in the Northern Great Plains (NGP) due to the lack of prescribed fire and planted ERC escaping from shelterbelts. This encroachment poses a threat to native plant communities in terms of their reproduction, regeneration, and diversity. ERC are fierce competitors and can establish in most soil types, are drought tolerant, and prolific seed reproducers. These qualities …


Machine-Learning And Meta-Analysis Techniques To Quantify And Predict Soil Organic Carbon, N2O-N And Co2-C Emissions In Cover Crop Systems, Deepak Raj Joshi Jan 2022

Machine-Learning And Meta-Analysis Techniques To Quantify And Predict Soil Organic Carbon, N2O-N And Co2-C Emissions In Cover Crop Systems, Deepak Raj Joshi

Electronic Theses and Dissertations

People worldwide are challenged by multiple threats including climate change, growing populations, and soil degradation. Addressing these challenges requires understanding of the local environment, farming systems and modern technologies. These technologies include new ways to process information that include artificial intelligence, machine learning and meta-analysis. Models produced using these technologies may be useful for predicting the consequences of implementing conservation practices that reduce GHG emissions as well as for determining the carbon footprint of cropping systems that include environmentally friendly conservation technologies such as growing cover crop. Therefore, our objectives of this study were to: 1) provide an overview of …


Searching For Pets: Using Distributional And Sentiment-Based Methods To Find Potentially Euphemistic Terms, Patrick Lee, Martha Gavidia, Anna Feldman, Jing Peng Jan 2022

Searching For Pets: Using Distributional And Sentiment-Based Methods To Find Potentially Euphemistic Terms, Patrick Lee, Martha Gavidia, Anna Feldman, Jing Peng

Department of Computer Science Faculty Scholarship and Creative Works

This paper presents a linguistically driven proof of concept for finding potentially euphemistic terms, or PETs. Acknowledging that PETs tend to be commonly used expressions for a certain range of sensitive topics, we make use of distributional similarities to select and filter phrase candidates from a sentence and rank them using a set of simple sentiment-based metrics. We present the results of our approach tested on a corpus of sentences containing euphemisms, demonstrating its efficacy for detecting single and multi-word PETs from a broad range of topics. We also discuss future potential for sentiment-based methods on this task.


A Report On The Euphemisms Detection Shared Task, Patrick Lee, Anna Feldman, Jing Peng Jan 2022

A Report On The Euphemisms Detection Shared Task, Patrick Lee, Anna Feldman, Jing Peng

Department of Computer Science Faculty Scholarship and Creative Works

This paper presents The Shared Task on Euphemism Detection for the Third Workshop on Figurative Language Processing (FigLang 2022) held in conjunction with EMNLP 2022. Participants were invited to investigate the euphemism detection task: given input text, identify whether it contains a euphemism. The input data is a corpus of sentences containing potentially euphemistic terms (PETs) collected from the GloWbE corpus (Davies and Fuchs, 2015), and are human-annotated as containing either a euphemistic or literal usage of a PET. In this paper, we present the results and analyze the common themes, methods and findings of the participating teams.


The Naming Of Homo Bodoensis By Roksandic And Colleagues Does Not Resolve Issues Surrounding Middle Pleistocene Human Evolution, Eric Delson, Chris Stringer Jan 2022

The Naming Of Homo Bodoensis By Roksandic And Colleagues Does Not Resolve Issues Surrounding Middle Pleistocene Human Evolution, Eric Delson, Chris Stringer

Publications and Research

Roksandic et al. (2022) proposed the new species name Homo bodoensis as a replacement name for Homo rhodesiensis Woodward, 1921, because they felt it was poorly and variably defined and was linked to sociopolitical baggage. However, the International Code of Zoological Nomenclature includes regulations on how and when such name changes are allowed, and Roksandic et al.'s arguments meet none of these requirements. It is not permitted to change a name solely because of variable (or erroneous) later use once it has been originally defined correctly, nor can a name be modified because it is offensive to one or more …


Beyond A Liberal Reading Of Insurgent In Transformative Planning Practices, Efadul Huq Jan 2022

Beyond A Liberal Reading Of Insurgent In Transformative Planning Practices, Efadul Huq

Environmental Science and Policy: Faculty Publications

No abstract provided.


Fire Emissions In The Tropical Indonesia: Improved Estimation And Driving Forces Investigation, Xiaoman Lu Jan 2022

Fire Emissions In The Tropical Indonesia: Improved Estimation And Driving Forces Investigation, Xiaoman Lu

Electronic Theses and Dissertations

Indonesia has experienced frequent fires since the 1970s due to large-scale peatland conversion and extensive drainage for agricultural development. Fire emissions released from these fires have led to Indonesia being the world’s 3rd largest emitter of greenhouse gases in certain years. Given that fire emissions severely affect climate, weather, and the human environment, numerous approaches have been developed to estimate fire emissions. However, existing emission estimates differ largely by a factor of four in this tropical country because of frequent cloud interferences and low-temperature smoldering fires. Therefore, this dissertation aims to improve the quantification of Indonesian fire emissions through enhanced …


Students’ Perceptions Of Specific Laboratory Curricula On The Learning Experience In Chemistry Courses, Arwa Ali Alshehri Jan 2022

Students’ Perceptions Of Specific Laboratory Curricula On The Learning Experience In Chemistry Courses, Arwa Ali Alshehri

Electronic Theses and Dissertations

Laboratory courses play a key role in developing critical thinking and problem-solving skills and providing experience in certain aspects of a laboratory setting including reactions, materials, and equipment. Prior studies suggest that a laboratory course assists students toward cognitive gain on lecture content. In contrast, other studies conclude that laboratory is uncorrelated with cognitive gain on lecture content. Thus, a discord exists between researchers regarding the role that laboratory experiences play in furthering the understanding of chemistry concepts taught in lectures. The purpose of this research is to examine the impact of two different laboratory curricula on students’ performance in …


Vietnamese Document Analysis: Dataset, Method And Benchmark Suite, Khang Nguyen, An Nguyen, Nguyen D. Vo, Tam Nguyen Jan 2022

Vietnamese Document Analysis: Dataset, Method And Benchmark Suite, Khang Nguyen, An Nguyen, Nguyen D. Vo, Tam Nguyen

Computer Science Faculty Publications

Document image understanding is increasingly useful since the number of digital documents is increasing day-by-day and the need for automation is increasing. Object detection plays a significant role in detecting vital objects and layouts in document images and contributes to providing a clearer understanding of the documents. Nonetheless, previous research mainly focuses on English document images, and studies on Vietnamese document images are limited. In this study, we extensively benchmark state-of-the-art object detectors and analyze the performance of each method on Vietnamese document images. Moreover, we also investigate the effectiveness of four different loss functions on the experimental object detection …


Biking In Indianapolis: An Ethnographic Analysis Of Obstacles And Solutions, Emory Lietz Jan 2022

Biking In Indianapolis: An Ethnographic Analysis Of Obstacles And Solutions, Emory Lietz

Undergraduate Honors Thesis Collection

Indiana is known as the ""Crossroads of America"" for its historic investment in vehicle infrastructure. This focus on automobiles has shaped Indianapolis's urban landscape, to the dismay of many cyclists. Based on semi-structured interviews with a range of stakeholders in the Indianapolis cycling community, including urban planners, bike commuters, IndyGo employees, city government officials, and bike advocates, this project identifies and evaluates the current barriers that prevent Indianapolis residents from riding their bikes. These obstacles, which include infrastructural, safety, and social factors, make it more difficult than it ought to be to bike in Indy.

For my thesis project, I …


Why Do Family Members Reject Ai In Health Care? Competing Effects Of Emotions, Eun Hee Park, Karl Werder, Lan Cao, Balasubramaniam Ramesh Jan 2022

Why Do Family Members Reject Ai In Health Care? Competing Effects Of Emotions, Eun Hee Park, Karl Werder, Lan Cao, Balasubramaniam Ramesh

Information Technology & Decision Sciences Faculty Publications

Artificial intelligence (AI) enables continuous monitoring of patients’ health, thus improving the quality of their health care. However, prior studies suggest that individuals resist such innovative technology. In contrast to prior studies that investigate individuals’ decisions for themselves, we focus on family members’ rejection of AI monitoring, as family members play a significant role in health care decisions. Our research investigates competing effects of emotions toward the rejection of AI monitoring for health care. Based on two scenario-based experiments, our study reveals that emotions play a decisive role in family members’ decision making on behalf of their parents. We find …


Computational Single-Cell Analysis Of Confocal Fluorescence Images With Dapi-Generated Masks, Munirah Alduhailan Jan 2022

Computational Single-Cell Analysis Of Confocal Fluorescence Images With Dapi-Generated Masks, Munirah Alduhailan

Wayne State University Theses

Lipolysis is a metabolic pathway in which free fatty acids are mobilized from stored triglycerides. The rate-limiting enzyme in this process is adipose triglyceride lipase, which is regulated by α/β-hydrolase domain-containing protein 5 (ABHD5) via both natural and synthetic pathways. With advanced artificial neural networks, image processing methods can extract quantitative results from fluorescence images. The segmentation of complex biological images, in which regions of the image are labeled as distinct masks, is the first step in image analysis. Ilastik, a machine-learning software, performs image segmentation with a user-trained neural network and custom key feature labels. The software’s results are …


Defending Against Adversarial Attacks On Medical Imaging Ai Systems, Xin Li Jan 2022

Defending Against Adversarial Attacks On Medical Imaging Ai Systems, Xin Li

Wayne State University Theses

Although deep learning systems trained on medical images have shown state-of-the-art performance in many clinical prediction tasks, recent studies demonstrate that these systems can be fooled by carefully crafted adversarial images. It has raised concerns on the practical deployment of deep learning based medical image classification systems. Although an array of defense techniques have been developed and proved to be effective in computer vision, defending against adversarial attacks on medical images remains largely an uncharted territory due to their unique challenges: crafted adversarial noises added to a highly standardized medical image can make it a hard sample for model to …


Speedster: An Efficient Multi-Party State Channel Via Enclaves, Jinghui Liao Jan 2022

Speedster: An Efficient Multi-Party State Channel Via Enclaves, Jinghui Liao

Wayne State University Theses

State channel network is the most popular layer-2 solution to the issues of scalability,high transaction fees, and low transaction throughput of public Blockchain networks. However, the existing works have limitations that curb the wide adoption of the technology, such as the expensive creation and closure of channels, strict synchronization between the main chain and off-chain channels, frozen deposits, and inability to execute multi-party smart contracts. In this work, we present Speedster, an account-based state-channel system that aims to address the above issues. To this end, Speedster leverages the latest development of secure hardware to create dispute-free certified channels that can …


Development Of Terpyridine-Based Metallosurfactants For Directional Electron Tunneling, Samudra Subashini Amunugama Jan 2022

Development Of Terpyridine-Based Metallosurfactants For Directional Electron Tunneling, Samudra Subashini Amunugama

Wayne State University Dissertations

The molecular electronics field is a multidisciplinary area that addresses the utilization of molecules as the basic unit of electronic components. Depending on the characteristics of the molecules, they can function as transistors, wires, switches, and memory cells. This field has attracted significant interest from the scientific community due to the increasing number of issues associated with the miniaturization process of microelectronic devices and the desirability of using molecules in electronic circuits. The research work discussed in this dissertation thesis is focused on the design and development of terpyridine-based metallosurfactant as prospective candidates for molecular electronics. Since rectifiers are pivotal …


Khovanov Homology & Uniqueness Of Surfaces In The 4-Ball, Isaac Sundberg Jan 2022

Khovanov Homology & Uniqueness Of Surfaces In The 4-Ball, Isaac Sundberg

Bryn Mawr College Dissertations and Theses

We use the functoriality of Khovanov homology to examine the smooth, boundary-preserving isotopy of surfaces embedded in the 4-ball. We exemplify an infinite family of prime knots that bound an arbitrarily-large number of smoothly-distinct slice disks by distinguishing the maps they induce on Khovanov homology. Similar techniques produce an infinite family of knots that each bound a pair of exotic surfaces of arbitrary genus.


Synthesis Of Highly Reactive Sulfone Iminium Fluorides And Their Use In Deoxyfluorination And Sulfur Fluoride Exchange Chemistry, James A. Vogel, Rania Hammami, Ara Ko, Hiya Datta, Yael N. Eiben, Karley J. Labenne, Ellis C. Mccarver, Ebrar Z. Yilmaz, Patrick R. Melvin Jan 2022

Synthesis Of Highly Reactive Sulfone Iminium Fluorides And Their Use In Deoxyfluorination And Sulfur Fluoride Exchange Chemistry, James A. Vogel, Rania Hammami, Ara Ko, Hiya Datta, Yael N. Eiben, Karley J. Labenne, Ellis C. Mccarver, Ebrar Z. Yilmaz, Patrick R. Melvin

Chemistry Faculty Research and Scholarship

We report the synthesis of sulfone iminium fluorides (SIFs), a reactive class of sulfur(VI) molecules. The synthesis is tolerant of a variety of substituents on the sulfur and nitrogen components. The SIF reagents were applied to the deoxyfluorination of alcohols and carboxylic acids, providing high yields of fluorinated products in 60 s at room temperature. The SIF reagents were then utilized in sulfur fluoride exchange (SuFEx), creating the first ionic SuFEx products to date.


Identification And Dosimetry Of Irradiated Pistachio (Pistacia Vera L.) Using Epr, Elsayed Salama, Ahmed M. Maghrabya, Samy A. Anwar, M. El-Sayed Jan 2022

Identification And Dosimetry Of Irradiated Pistachio (Pistacia Vera L.) Using Epr, Elsayed Salama, Ahmed M. Maghrabya, Samy A. Anwar, M. El-Sayed

Basic Science Engineering

In the current study, the EPR signal of both gamma-irradiated shell and kernel of the pistachio is recorded and investigated. The spectrum properties, microwave power dependency of signal intensities, short- and long-term temporal dependencies, and other significant factors are studied. This investigation was done on how varying radiation doses (0–10 kGy) affected the reactions of pistachio shells and kernels. The time dependence of the radiation-induced signal intensity of pistachio showed that the maximum intensity reached about 98.75% and 67% of its original value for shells and kernels, respectively, after the first six hours. These results indicate that EPR is an …


An Odd-Protocol For Agent-Based Model For The Spread Of Covid-19 In Ireland, Elizabeth Hunter, John D. Kelleher Jan 2022

An Odd-Protocol For Agent-Based Model For The Spread Of Covid-19 In Ireland, Elizabeth Hunter, John D. Kelleher

Reports

No abstract provided.


Dative Epitaxy Of Commensurate Monocrystalline Covalent Van Der Waals Moiré Supercrystal, Mengying Bian, Liang Zhu, Xiao Wang, Junho Choi, Rajesh V. Chopdekar, Sichen Wei, Lishu Wu, Chang Huai, Austin Marga, Qishuo Yang, Yuguang C. Li, Fei Yao, Ting Yu, Scott A. Crooker National High Magnetic Field Laboratory, Los Alamos National Laboratory, Xuemei Cheng, Renat F. Sabirianov, Shengbai Zhang, Junhao Lin, Yanglong Hou, Hao Zeng Jan 2022

Dative Epitaxy Of Commensurate Monocrystalline Covalent Van Der Waals Moiré Supercrystal, Mengying Bian, Liang Zhu, Xiao Wang, Junho Choi, Rajesh V. Chopdekar, Sichen Wei, Lishu Wu, Chang Huai, Austin Marga, Qishuo Yang, Yuguang C. Li, Fei Yao, Ting Yu, Scott A. Crooker National High Magnetic Field Laboratory, Los Alamos National Laboratory, Xuemei Cheng, Renat F. Sabirianov, Shengbai Zhang, Junhao Lin, Yanglong Hou, Hao Zeng

Physics Faculty Research and Scholarship

Realizing van der Waals (vdW) epitaxy in the 1980s represents a breakthrough that circumvents the stringent lattice matching and processing compatibility requirements in conventional covalent heteroepitaxy. However, due to the weak vdW interactions, there is little control over film qualities by the substrate. Typically, discrete domains with a spread of misorientation angles are formed, limiting the applicability of vdW epitaxy. Here, the epitaxial growth of monocrystalline, covalent Cr5Te8 2D crystals on monolayer vdW WSe2 by chemical vapor deposition is reported, driven by interfacial dative bond formation. The lattice of Cr5Te8, with a lateral dimension of a few tens of micrometers, …


Bending Waves Excited By Irregular Gas Inflow Along Warps, Tigran Khachaturyants, Leandro Beraldo E Silva, Victor P. Debattista, Kathryne J. Daniel Jan 2022

Bending Waves Excited By Irregular Gas Inflow Along Warps, Tigran Khachaturyants, Leandro Beraldo E Silva, Victor P. Debattista, Kathryne J. Daniel

Physics Faculty Research and Scholarship

Gaia has revealed clear evidence of bending waves in the vertical kinematics of stars in the solar neighbourhood. We study bending waves in two simulations, one warped, with the warp due to misaligned gas inflow, and the other unwarped. We find slow, retrograde bending waves in both models, with the ones in the warped model having larger amplitudes. We also find fast, prograde bending waves. Prograde bending waves in the unwarped model are very weak, in agreement with the expectation that these waves should decay on short, approximately crossing, time-scales, due to strong winding. However, prograde bending waves are much …


Persistent Opto-Ferroelectric Responses In Molecular Ferroelectrics, Xuanyuan Jiang, Xiao Wang, Pratyush Buragohain, Andy T. Clark, Haidong Lu, Shashi Poddar, Le Yu, Anthony D. Dichiara, Alexei Gruverman, Xuemei Cheng, Xiaoshan Xu Jan 2022

Persistent Opto-Ferroelectric Responses In Molecular Ferroelectrics, Xuanyuan Jiang, Xiao Wang, Pratyush Buragohain, Andy T. Clark, Haidong Lu, Shashi Poddar, Le Yu, Anthony D. Dichiara, Alexei Gruverman, Xuemei Cheng, Xiaoshan Xu

Physics Faculty Research and Scholarship

Persistent photoresponses require optical excitations to metastable states, which are rare of ionic origin due to the indirect photon-ion interaction. In this work, we explore the photoinduced metastable proton states in the proton-transfer type molecular ferroelectric croconic acid. We observe that, after the photoexcitation, the changes of structural and ferroelectric properties relax in ∼10^3s, indicating persistent photoresponses of ionic origin. In contrast, the photoconductivity relaxes within 1 s. The 10^3s timescale suggests that the ionic metastable states result from proton transfer both along and out of the hydrogen bonds. This discovery unveils an ionic mechanism for the phototunability, which offers …


Impact Of The Electron Density And Temperature Gradient On Drift-Wave Turbulence In The Large Plasma Device, Conor Perks, Saskia Mordijck, Troy Carter, Bart Van Compernolle, Stephen Vincena, Giovanni Rossi, David A. Schaffner Jan 2022

Impact Of The Electron Density And Temperature Gradient On Drift-Wave Turbulence In The Large Plasma Device, Conor Perks, Saskia Mordijck, Troy Carter, Bart Van Compernolle, Stephen Vincena, Giovanni Rossi, David A. Schaffner

Physics Faculty Research and Scholarship

In this paper we present an experimental study of edge turbulence in the Large Plasma Device at UCLA. We utilize a scan of discharge power and prefill pressure (neutral density) to show experimentally that turbulent density fluctuations decrease with decreasing density gradient, as predicted for resistive drift-wave turbulence (RDWT). As expected for RDWT, we observe that the cross-phase between the density and potential fluctuations is close to 0. Moreover, the addition of an electron temperature gradient leads to a reduction in the amplitude of the density fluctuations, as expected for RDWT. However, counter to theoretical expectations, we find that the …


Topological Spin Memory Of Antiferromagnetically Coupled Skyrmion Pairs In Co/Gd/Pt Multilayers, Xiao Wang, Alexandra R. Stuart, Mitchell S. Swyt, Carla M. Quispe Flores, Andy T. Clark, Adzo Fiagbenu, Rajesh V. Chopdekar, Pavel N. Lapa, Zhuyun Xiao, Dava Keavney, Richard Rosenberg, Michael Vogel, John E. Pearson, Suzanne G. E. Te Velthius, Axel Hoffmann, Kristen S. Buchanan, Xuemei Cheng Jan 2022

Topological Spin Memory Of Antiferromagnetically Coupled Skyrmion Pairs In Co/Gd/Pt Multilayers, Xiao Wang, Alexandra R. Stuart, Mitchell S. Swyt, Carla M. Quispe Flores, Andy T. Clark, Adzo Fiagbenu, Rajesh V. Chopdekar, Pavel N. Lapa, Zhuyun Xiao, Dava Keavney, Richard Rosenberg, Michael Vogel, John E. Pearson, Suzanne G. E. Te Velthius, Axel Hoffmann, Kristen S. Buchanan, Xuemei Cheng

Physics Faculty Research and Scholarship

Antiferromagnetically (AFM) coupled skyrmions offer potential advantages for spintronic devices, including reduced dipolar fields that may enable smaller skyrmion sizes and a reduction of the skyrmion Hall effect. However, the topological stability of AFM-coupled skyrmions subjected to dramatic spin deformation through low-temperature cycling has not been investigated. Here we report the discovery of a topological spin memory effect for AFM-coupled skyrmion pairs in [Co/Gd/Pt]10 multilayered films. Photoemission electron microscopy imaging shows that bubble skyrmions in the multilayer that are stable at room temperature evolve into complex in-plane spin textures as the temperature is lowered and reform completely when the sample …


The Effects Of Field History On Magnetic Skyrmion Formation In [Pt/Co/ Ir]3 Multilayers, Andy T. Clark, Xiaogang Wang, Alexandra R. Stuart, Qiang Wang, Wei Jiang, John E. Pearson, Suzanne G. E. Te Velthuis, Axel Hoffman, Xuemei Cheng, Kristen S. Buchanan Jan 2022

The Effects Of Field History On Magnetic Skyrmion Formation In [Pt/Co/ Ir]3 Multilayers, Andy T. Clark, Xiaogang Wang, Alexandra R. Stuart, Qiang Wang, Wei Jiang, John E. Pearson, Suzanne G. E. Te Velthuis, Axel Hoffman, Xuemei Cheng, Kristen S. Buchanan

Physics Faculty Research and Scholarship

We report on the formation of Néel-type magnetic bubble skyrmions at room temperature in [Pt/Co/Ir]3 multilayered thin films after an in-plane magnetic field treatment. Polar magneto-optical Kerr Effect (p-MOKE) microscopy images show that the dendritic magnetic configurations observed after AC demagnetization evolve into magnetic bubble skyrmions after the application and subsequent removal of an in-plane magnetic field. Micromagnetic simulations were used to systematically investigate the role of the in-plane magnetic field magnitude, misalignment of the sample, and the Dzyaloshinskii-Moriya interactions (DMI) in generating bubble skyrmions during the field treatment. The simulations show that in-plane fields slightly below the saturation field …


Measurement Of The Taylor Scale In A Magnetized Turbulent Laboratory Plasma Wind-Tunnel, Carlos A. Cartagena-Sanchez, Joshua M. Carlson, David A. Schaffner Jan 2022

Measurement Of The Taylor Scale In A Magnetized Turbulent Laboratory Plasma Wind-Tunnel, Carlos A. Cartagena-Sanchez, Joshua M. Carlson, David A. Schaffner

Physics Faculty Research and Scholarship

The fluid Taylor scale is measured in the Bryn Mawr Experiment (BMX) of the Bryn Mawr Plasma Laboratory and examined as a potential dissipation scale of magnetic turbulence within the plasma. We present the first laboratory measurements of the Taylor scale of a turbulent magnetized plasma through multi-point correlations of broadband magnetic fluctuations. From spatial and temporal correlations, respectively, the measured Taylor scales are 261 and 361 cm. These measurements are on the same order of magnitude as estimated ion dissipation scales within the BMX plasma with ion inertial scales between 1 and 10 cm and ion gyroscales between 0:1 …


Mineral Displays As Embodiments Of Geologic Thought And Colonial Invisibility, Selby Hearth, Carrie Robbins Jan 2022

Mineral Displays As Embodiments Of Geologic Thought And Colonial Invisibility, Selby Hearth, Carrie Robbins

Geology Faculty Research and Scholarship

Mineral displays embodied how we think about minerals: as symbols of social status, scholarly tools, theological objects, and instruments of education. Mineral displays are also representations of how we don’t think about minerals: as human products embedded in wider human histories. This paper reviews the historical themes in mineral display, from the cabinets of curiosity of the Renaissance to modern museums, and articulates a major narrative that has been omitted from mineral display traditions: the human processes that bring mineral specimens from the ground to the display case, particularly Western colonialism and labour. Historically, mineral displays have been used to …