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Accurate Covariance Estimation For Pose Data From Iterative Closest Point Algorithm, Rick H. Yuan, Clark N. Taylor, Scott L. Nykl Jul 2023

Accurate Covariance Estimation For Pose Data From Iterative Closest Point Algorithm, Rick H. Yuan, Clark N. Taylor, Scott L. Nykl

Faculty Publications

One of the fundamental problems of robotics and navigation is the estimation of the relative pose of an external object with respect to the observer. A common method for computing the relative pose is the iterative closest point (ICP) algorithm, where a reference point cloud of a known object is registered against a sensed point cloud to determine relative pose. To use this computed pose information in downstream processing algorithms, it is necessary to estimate the uncertainty of the ICP output, typically represented as a covariance matrix. In this paper, a novel method for estimating uncertainty from sensed data is …

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Review-From Educational Experiment To Standard Bearer: University 101 At The University Of South Carolina, Blake Denton Jul 2023

Review-From Educational Experiment To Standard Bearer: University 101 At The University Of South Carolina, Blake Denton

Faculty Publications

In 2022, the University of South Carolina observed the fiftieth anniversary of its innovative “University 101” experiment and the course’s legacy as the leading model of the “first-year experience” movement in higher education. Simply stated, University 101 is an extended orientation seminar designed to facilitate new students’ transition to college and campus life at the flagship. In this commemorative edited volume, eleven contributors affiliated with South Carolina collectively document the history, evolution, and impact of the institution’s renowned University 101 Programs (now a multifaceted enterprise that oversees and fosters every aspect of the campus’s first-year experience) on generations of the …

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Computational Materials Design For Ceramic Nuclear Waste Forms Using Machine Learning, First-Principles Calculations, And Kinetics Rate Theory, Jianwei Wang, Dipta B. Ghosh, Zelong Zhang Jul 2023

Computational Materials Design For Ceramic Nuclear Waste Forms Using Machine Learning, First-Principles Calculations, And Kinetics Rate Theory, Jianwei Wang, Dipta B. Ghosh, Zelong Zhang

Faculty Publications

Ceramic waste forms are designed to immobilize radionuclides for permanent disposal in geological repositories. One of the principal criteria for the effective incorporation of waste elements is their compatibility with the host material. In terms of performance under environmental conditions, the resistance of the waste forms to degradation over long periods of time is a critical concern when they are exposed to natural environments. Due to their unique crystallographic features and behavior in nature environment as exemplified by their natural analogues, ceramic waste forms are capable of incorporating problematic nuclear waste elements while showing promising chemical durability in aqueous environments. …

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Laminar Flame Speed Measurements Of A Gasoline Surrogate And Its Mixtures With Ethanol At Elevated Pressure And Temperature, Yousef M. Almarzooq, Ingmar Schoegl, Eric L. Petersen Jul 2023

Laminar Flame Speed Measurements Of A Gasoline Surrogate And Its Mixtures With Ethanol At Elevated Pressure And Temperature, Yousef M. Almarzooq, Ingmar Schoegl, Eric L. Petersen

Faculty Publications

Laminar Flame speed measurements of a gasoline surrogate and mixtures of it with ethanol were conducted using a heated, constant-volume vessel. A spherical propagating flame was observed using a high-speed camera, and laminar flame speed was determined therefrom. The gasoline surrogate, which serves as the baseline for the current study, consisted of four components, namely, iso-octane, n-heptane, toluene, and 1-hexene. Different mixtures of the gasoline surrogate and ethanol were studied, governed by the ethanol percentage in the mixture. That is, E0, E30, E50, and E85 mixtures represent 0%, 30%, 50%, and 85% ethanol in the gasoline surrogate mixture by liquid …

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Three-Dimensional Scaffolds For Bone Tissue Engineering, Harish Chinnasami, Mohan Kumar Dey, Ram Devireddy Jul 2023

Three-Dimensional Scaffolds For Bone Tissue Engineering, Harish Chinnasami, Mohan Kumar Dey, Ram Devireddy

Faculty Publications

Immobilization using external or internal splints is a standard and effective procedure to treat minor skeletal fractures. In the case of major skeletal defects caused by extreme trauma, infectious diseases or tumors, the surgical implantation of a bone graft from external sources is required for a complete cure. Practical disadvantages, such as the risk of immune rejection and infection at the implant site, are high in xenografts and allografts. Currently, an autograft from the iliac crest of a patient is considered the “gold standard” method for treating large-scale skeletal defects. However, this method is not an ideal solution due to …

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Developing Sustainable Asphalt Mixtures Using High-Density Polyethylene Plastic Waste Material, Ibrahim Elnaml, Jun Liu, Louay N. Mohammad, Nazimuddin Wasiuddin, Samuel B. Cooper, Samuel B. Cooper Jul 2023

Developing Sustainable Asphalt Mixtures Using High-Density Polyethylene Plastic Waste Material, Ibrahim Elnaml, Jun Liu, Louay N. Mohammad, Nazimuddin Wasiuddin, Samuel B. Cooper, Samuel B. Cooper

Faculty Publications

There is growing interest in sustainable road pavement technologies to protect the environment and provide economic benefits. Post-consumer recycled (PCR) plastics are considered for construction to address the threat of plastic waste materials (PWM) and to improve sustainability. Asphalt pavement construction is highly considered for PWM recycling due to its large daily production. The purpose of this study is to investigate the performance of asphalt mixture containing PWM, specifically high-density polyethylene (HDPE), and compare its performance with two conventional mixtures. Three asphalt mixtures were considered: (1) mixture with asphalt binder PG 76-22 (SBS-modified); (2) mixture with asphalt binder PG 70-22 …

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Measuring Resilience To Sea-Level Rise For Critical Infrastructure Systems: Leveraging Leading Indicators, Lamis Amer, Murat Erkoc, Rusty A. Feagin, Sabarethinam Kameshwar, Katharine J. Mach, Diana Mitsova Jul 2023

Measuring Resilience To Sea-Level Rise For Critical Infrastructure Systems: Leveraging Leading Indicators, Lamis Amer, Murat Erkoc, Rusty A. Feagin, Sabarethinam Kameshwar, Katharine J. Mach, Diana Mitsova

Faculty Publications

There has been a growing interest in research on how to define and build indicators of resilience to address challenges associated with sea-level rise. Most of the proposed methods rely on lagging indicators constructed based on the historical performance of an infrastructure sub-system. These indicators are traditionally utilized to build curves that describe the past response of the sub-system to stressors; these curves are then used to predict the future resilience of the sub-system to hypothesized events. However, there is now a growing concern that this approach cannot provide the best insights for adaptive decision-making across the broader context of …

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Every Step You Take, I'Ll Be Tracking You: Forensic Analysis Of The Tile Tracker Application, Lauren R. Pace, La Sean A. Salmon, Christopher J. Bowen, Ibrahim Baggili, Golden G. Richard Jul 2023

Every Step You Take, I'Ll Be Tracking You: Forensic Analysis Of The Tile Tracker Application, Lauren R. Pace, La Sean A. Salmon, Christopher J. Bowen, Ibrahim Baggili, Golden G. Richard

Faculty Publications

The rise in popularity of personal Bluetooth trackers has incited a need for forensic analysis tools that aid law enforcement in artifact recovery. With 40 million Tile devices reportedly sold at the time of writing, Tile trackers are one of the most popular personal Bluetooth trackers. This growth has not been without consequence, as reports of Bluetooth trackers being used for malicious activities have also escalated. Our work presents a forensic analysis of the Tile ecosystem and the Tile application on iOS, Android, and Windows. This analysis revealed valuable forensic artifacts that contained a diverse set of sensitive user data, …

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Crgb_Mem: At The Intersection Of Memory Forensics And Machine Learning, Aisha Ali-Gombe, Sneha Sudhakaran, Ramyapandian Vijayakanthan, Golden G. Richard Jul 2023

Crgb_Mem: At The Intersection Of Memory Forensics And Machine Learning, Aisha Ali-Gombe, Sneha Sudhakaran, Ramyapandian Vijayakanthan, Golden G. Richard

Faculty Publications

Mobile malware's alarming sophistication and pervasiveness have continued to draw the attention of many cybersecurity researchers. Particularly on the Android platform, malware trojans designed to steal user PIIs, crypto miners, ransomware, and on-device fraud continue to infiltrate the primary Google store market and other secondary markets. While much effort has been put in place by the research community and industry to curb this menace since 2012, malware authors have consistently found ways to circumvent the existing detection and prevention mechanisms. Largely this remains so because of the restrictiveness of the feature set used in building the current classification models. Thus, …

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Flammability Properties Of The Pyrolysis Gas Generated From Willow Wood, Maria Mitu, Domnina Razus, Dorin Boldor, Cosmin Marculescu Jul 2023

Flammability Properties Of The Pyrolysis Gas Generated From Willow Wood, Maria Mitu, Domnina Razus, Dorin Boldor, Cosmin Marculescu

Faculty Publications

Willow wood presents a real interest for biomass pyrolysis due to its fast growth, renewability, and high energy density. Following the pyrolysis of willow wood in an inert atmosphere, a multi-fuel gaseous mixture was obtained, with the following composition (by volume): 38.20% CO/21.87% H2/17.44% CH4/1.15% O2/17.15% CO2/4.19% N2. The propagation of laminar premixed flames in these multifuel mixtures with air was investigated numerically for initial temperatures from 298 to 500 K, initial pressures from 1 to 20 bar, and fuel equivalence ratios between 0.60 and 2.00. The combustion of these gaseous mixtures as free laminar premixed flames was simulated by …

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A Case For An Independent Cyber Force, Ian C. Heffron, Mark Reith, James W. Dean Jul 2023

A Case For An Independent Cyber Force, Ian C. Heffron, Mark Reith, James W. Dean

Faculty Publications

Although cyberspace is considered the newest warfighting domain, military analysts and scholars have opined the United States remains woefully behind its peers in cyberspace and have called for the creation of a separate cyber service component. Yet a cohesive and robust discussion on this topic has yet to emerge. This article proposes a general framework that builds on the Joint doctrine, organization, training, materiel, leadership and education, personnel, facilities, and policy (DOTMLPF-P) analysis to address questions of sufficiency and necessity. Such analysis reveals DoD cyber operations do not maximize the United States’ ability to fight a cyber war, especially when …

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Effects Of Atlantic Butterfish (Peprilus Triacanthus) In Diets Of Common Terns (Sterna Hirundo): A Case Study Of Climate Change Effects In The Gulf Of Maine, Olivia A. Smith, Elizabeth C. Craig Jul 2023

Effects Of Atlantic Butterfish (Peprilus Triacanthus) In Diets Of Common Terns (Sterna Hirundo): A Case Study Of Climate Change Effects In The Gulf Of Maine, Olivia A. Smith, Elizabeth C. Craig

Faculty Publications

Climate change and associated shifts in marine prey communities can alter food availability for foraging seabirds. This issue is illustrated in the Gulf of Maine by the northward shift of Atlantic butterfish (Peprilus triacanthus; hereafter butterfish) and their subsequent increase in seabird diets. Here, we examine effects of butterfish in diets of the Common Tern (Sterna hirundo), a threatened species in this region. Our objectives were to evaluate butterfish suitability for tern chick diet through observing handling time and feeding success, to examine effects of butterfish on tern chick growth, and to explore signs of adaptive foraging in adults. The …

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Learning By Doing In The Segregated South: The Robert Hungerford Normal And Industrial School For African Americans In Central Florida, Wenxian Zhang Jul 2023

Learning By Doing In The Segregated South: The Robert Hungerford Normal And Industrial School For African Americans In Central Florida, Wenxian Zhang

Faculty Publications

The development of the Robert Hungerford Normal and Industrial School is an important chapter in the history of African American education in Florida. Through careful examinations of the school publications, records, archival correspondence, and newspaper clippings, the article seeks to document the history of the Hungerford School from its founding in the late nineteenth century until it became a public school in the Orange County, Florida in the early 1950s. Following Booker T. Washington’s ideals, the school was established with a great emphasis on economic self-help and individual advancement for African Americans. Its mission was to teach vocational skills to …

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Packets-To-Prediction: An Unobtrusive Mechanism For Identifying Coarse-Grained Sleep Patterns With Wifi Mac Layer Traffic, Dheryta Jaisinghani, Nishtha Phutela Jul 2023

Packets-To-Prediction: An Unobtrusive Mechanism For Identifying Coarse-Grained Sleep Patterns With Wifi Mac Layer Traffic, Dheryta Jaisinghani, Nishtha Phutela

Faculty Publications

A good night’s sleep is of the utmost importance for the seamless execution of our cognitive capabilities. Unfortunately, the research shows that one-third of the US adult population is severely sleep deprived. With college students as our focused group, we devised a contactless, unobtrusive mechanism to detect sleep patterns, which, contrary to existing sensor-based solutions, does not require the subject to put on any sensors on the body or buy expensive sleep sensing equipment. We named this mechanism Packets-to-Predictions(P2P) because we leverage the WiFi MAC layer traffic collected in the home and university environments to predict “sleep” and “awake” periods. …

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Cost Estimation Trends For Major Defense Acquisition Programs, Sammantha Jones, Edward D. White, Jonathan D. Ritschel, Shawn M. Valentine Jul 2023

Cost Estimation Trends For Major Defense Acquisition Programs, Sammantha Jones, Edward D. White, Jonathan D. Ritschel, Shawn M. Valentine

Faculty Publications

The authors use both descriptive and inferential techniques to investigate average and standard deviation trends in cost estimates for major defense acquisition programs (MDAPs) grouped into decades from the 1970s to 2010s. For total program-cost-growth factors (CGFs), the 2010s exhibited lower CGFs compared to the 1990s. For the program-acquisition-unit cost (PAUC) CGFs, the 2010s appear lower than the 1990s and borderline lower than the 1970s. A statistically significant decreasing trend in the standard deviations of total program CGFs throughout the decades was identified. This lowering variability trend also appeared for PAUC CGFs from the 1980s onward. This finding appears to …

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Domain Restriction Zones: An Evolution Of The Military Exclusion Zone, Cole M. Mooty, Robert A. Bettinger, Mark G. Reith Jul 2023

Domain Restriction Zones: An Evolution Of The Military Exclusion Zone, Cole M. Mooty, Robert A. Bettinger, Mark G. Reith

Faculty Publications

Since the early part of the twenty-first century, US adversaries have expanded their military capabilities within and their access to new warfighting domains. When faced with the growth of adversaries’ asymmetric capabilities, the means, tactics, and strategies previously used by the US military lose their proportional effectiveness. To avoid such degradation of capability, the operational concept of the military exclusion zone (MEZ) should be revised to suit the modern battlespace while also addressing the shifts in national policy that encourage diplomacy over military force. The concept and development of domain restriction zones (DRZs) increase the relevancy of traditional MEZs in …

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A Comparison Of Quaternion Neural Network Backpropagation Algorithms, Jeremiah Bill, Bruce A. Cox, Lance Champaign Jun 2023

A Comparison Of Quaternion Neural Network Backpropagation Algorithms, Jeremiah Bill, Bruce A. Cox, Lance Champaign

Faculty Publications

This research paper focuses on quaternion neural networks (QNNs) - a type of neural network wherein the weights, biases, and input values are all represented as quaternion numbers. Previous studies have shown that QNNs outperform real-valued neural networks in basic tasks and have potential in high-dimensional problem spaces. However, research on QNNs has been fragmented, with contributions from different mathematical and engineering domains leading to unintentional overlap in QNN literature. This work aims to unify existing research by evaluating four distinct QNN backpropagation algorithms, including the novel GHR-calculus backpropagation algorithm, and providing concise, scalable implementations of each algorithm using a …

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Intrinsic Point Defects (Vacancies And Antisites) In Cdgep2 Crystals, Timothy D. Gustafson, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, Kent L. Averett, Jonathan E. Slagle, Larry E. Halliburton Jun 2023

Intrinsic Point Defects (Vacancies And Antisites) In Cdgep2 Crystals, Timothy D. Gustafson, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, Kent L. Averett, Jonathan E. Slagle, Larry E. Halliburton

Faculty Publications

Cadmium germanium diphosphide (CdGeP2) crystals, with versatile terahertz-generating properties, belong to the chalcopyrite family of nonlinear optical materials. Other widely investigated members of this family are ZnGeP2 and CdSiP2. The room-temperature absorption edge of CdGeP2 is near 1.72 eV (720 nm). Cadmium vacancies, phosphorous vacancies, and germanium-on-cadmium antisites are present in as-grown CdGeP2 crystals. These unintentional intrinsic point defects are best studied below room temperature with electron paramagnetic resonance (EPR) and optical absorption. Prior to exposure to light, the defects are in charge states that have no unpaired spins. Illuminating a CdGeP2 …

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Empowering Student Success: Unlocking The Potential Of Project-Based Steel Design Education, Aly Mousaad Aly Jun 2023

Empowering Student Success: Unlocking The Potential Of Project-Based Steel Design Education, Aly Mousaad Aly

Faculty Publications

In the pursuit of student success, it is essential to acknowledge that a singular teaching style does not universally cater to all students. The educator's crucial role lies in creating an optimal learning environment that fosters students' endeavors to excel. This endeavor transcends mere classroom success or employment prospects, encompassing a broader impact on societal well-being. An experiential learning approach, where students actively engage in practical tasks, emerges as the most effective mode of instruction. Integrating project-based learning activities into the curriculum holds immense potential for enhancing student learning. Additionally, the utilization of analysis software tools like FTool and STAAD …

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A Multi-Scale Method For Combined Design And Dispatch Optimization Of Nuclear Hybrid Energy Systems Including Storage, Daniel Hill, Dawson Mccrea, An Ho, Matthew Memmott, Kody Powell, John Hedengren Jun 2023

A Multi-Scale Method For Combined Design And Dispatch Optimization Of Nuclear Hybrid Energy Systems Including Storage, Daniel Hill, Dawson Mccrea, An Ho, Matthew Memmott, Kody Powell, John Hedengren

Faculty Publications

Reliable, carbon-free power generation is increasing in importance. Nuclear-renewable hybrid energy systems (NHES) are a potential solution for current generation challenges, but design and dispatch optimization for these systems remains challenging particularly when stochastic effects, long time horizons and nonlinear modeling are needed. This work presents a multi-scale method for combining the design and dispatch optimization problems for nonlinear NHES over long time horizons. Rather than treating the entire horizon as a single optimization problem, a large number of combined optimization problems are solved for shorter samples of the horizon resulting in distributions of optimal capacities for each of the …

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Academic Success And Retention Pathway For Mechanical Engineering Major, Paul Akangah, Henry Ivuawuogu, Adeola Morawo, Andrea Nana Ofori-Boadu Jun 2023

Academic Success And Retention Pathway For Mechanical Engineering Major, Paul Akangah, Henry Ivuawuogu, Adeola Morawo, Andrea Nana Ofori-Boadu

Faculty Publications

Evaluating student success in higher education relies heavily on Grade Point Average (GPA), a measure determined by faculty through formative and summative assessments. Faculty determine these grades throughout the student's academic career. Society often equates higher grades with greater intelligence and engagement, assuming students work independently. Grades are also a means to measure or quantify learning and intellectual progress during students' academic careers. However, when students resort to unsanctioned online resources (UORs) using applications like Chegg, Course Hero, and Slader, the student may obtain good grades, but understanding and learning are grossly sacrificed. This study investigates the performance of 100 …

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Academic Success And Retention Pathway For Mechanical Engineering Major, Paul Akangah, Henry Ivuawuogu, Adeola Morawo, Andrea Nana Ofori-Boadu Jun 2023

Academic Success And Retention Pathway For Mechanical Engineering Major, Paul Akangah, Henry Ivuawuogu, Adeola Morawo, Andrea Nana Ofori-Boadu

Faculty Publications

Evaluating student success in higher education relies heavily on Grade Point Average (GPA), a measure determined by faculty through formative and summative assessments. Faculty determine these grades throughout the student's academic career. Society often equates higher grades with greater intelligence and engagement, assuming students work independently. Grades are also a means to measure or quantify learning and intellectual progress during students' academic careers. However, when students resort to unsanctioned online resources (UORs) using applications like Chegg, Course Hero, and Slader, the student may obtain good grades, but understanding and learning are grossly sacrificed. This study investigates the performance of 100 …

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Optimal Estimation Inversion Of Ionospheric Electron Density From Gnss-Pod Limb Measurements: Part I-Algorithm And Morphology, Dong L. Wu, Nimalan Swarnalingam, Cornelius C. J. H. Salinas, Daniel J. Emmons, Tyler C. Summers, Robert Gardiner-Garden Jun 2023

Optimal Estimation Inversion Of Ionospheric Electron Density From Gnss-Pod Limb Measurements: Part I-Algorithm And Morphology, Dong L. Wu, Nimalan Swarnalingam, Cornelius C. J. H. Salinas, Daniel J. Emmons, Tyler C. Summers, Robert Gardiner-Garden

Faculty Publications

GNSS-LEO radio links from Precise Orbital Determination (POD) and Radio Occultation (RO) antennas have been used increasingly in characterizing the global 3D distribution and variability of ionospheric electron density (Ne). In this study, we developed an optimal estimation (OE) method to retrieve Ne profiles from the slant total electron content (hTEC) measurements acquired by the GNSS-POD links at negative elevation angles (ε < 0°). Although both OE and onion-peeling (OP) methods use the Abel weighting function in the Ne inversion, they are significantly different in terms of performance in the lower ionosphere. The new OE results can overcome the large Ne oscillations, sometimes negative values, seen in the OP retrievals in the E-region ionosphere. In the companion paper in this Special Issue, the HmF2 and NmF2 from the OE retrieval are validated against ground-based ionosondes and radar observations, showing generally good agreements in NmF2 from all sites. Nighttime hmF2 measurements tend to agree better than the daytime when the ionosonde heights tend to be slightly lower. The OE algorithm has been applied to all GNSS-POD data acquired from the COSMIC-1 (2006–2019), COSMIC-2 (2019–present), and Spire (2019–present) constellations, showing a consistent ionospheric Ne morphology. The unprecedented spatiotemporal sampling of the ionosphere from these constellations now allows a detailed analysis of the frequency–wavenumber spectra for the Ne variability at different heights. In the lower ionosphere (~150 km), we found significant spectral power in DE1, DW6, DW4, SW5, and SE4 wave components, in addition to well-known DW1, SW2, and DE3 waves. In the upper ionosphere (~450 km), additional wave components are still present, including DE4, DW4, DW6, SE4, and SW4. The co-existence of eastward- and westward-propagating wave4 components implies the presence of a stationary wave4 (SPW4), as suggested by other earlier studies. Further improvements to the OE method are proposed, including a tomographic inversion technique that leverages the asymmetric sampling about the tangent point associated with GNSS-LEO links.

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Advancing Flame Retardant Prediction: A Self-Enforcing Machine Learning Approach For Small Datasets, Cheng Yan, Xiang Lin, Xiaming Feng, Hongyu Yang, Patrick Mensah, Guoqiang Li Jun 2023

Advancing Flame Retardant Prediction: A Self-Enforcing Machine Learning Approach For Small Datasets, Cheng Yan, Xiang Lin, Xiaming Feng, Hongyu Yang, Patrick Mensah, Guoqiang Li

Faculty Publications

Improving the fireproof performance of polymers is crucial for ensuring human safety and enabling future space colonization. However, the complexity of the mechanisms for flame retardant and the need for customized material design pose significant challenges. To address these issues, we propose a machine learning (ML) framework based on substructure fingerprinting and self-enforcing deep neural networks (SDNN) to predict the fireproof performance of flame-retardant epoxy resins. Our model is based on a comprehensive understanding of the physical mechanisms of materials and can predict fireproof performance and eliminate the needs for properties descriptors, making it more convenient than previous ML models. …

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Intrinsically Stretchable Three Primary Light-Emitting Films Enabled By Elastomer Blend For Polymer Light-Emitting Diodes, Min Woo Jeong, Jin Hyun Ma, Jae Sung Shin, Jun Su Kim, Guorong Ma, Tae Uk Nam, Xiaodan Gu, Seong Jun Kang, Jin Young Oh Jun 2023

Intrinsically Stretchable Three Primary Light-Emitting Films Enabled By Elastomer Blend For Polymer Light-Emitting Diodes, Min Woo Jeong, Jin Hyun Ma, Jae Sung Shin, Jun Su Kim, Guorong Ma, Tae Uk Nam, Xiaodan Gu, Seong Jun Kang, Jin Young Oh

Faculty Publications

Intrinsically stretchable light-emitting materials are crucial for skin-like wearable displays; however, their color range has been limited to green-like yellow lights owing to the restricted stretchable light-emitting materials (super yellow series materials). To develop skin-like full-color displays, three intrinsically stretchable primary light-emitting materials [red, green, and blue (RGB)] are essential. In this study, we report three highly stretchable primary light-emitting films made from a polymer blend of conventional RGB light-emitting polymers and a nonpolar elastomer. The blend films consist of multidimensional nanodomains of light-emitting polymers that are interconnected in an elastomer matrix for efficient light-emitting under strain. The RGB blend …

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Determining Ion Activity Coefficients In Ion-Exchange Membranes With Machine Learning And Molecular Dynamics Simulations, Hishara Keshani Gallage Dona, Teslim Olayiwola, Luis A. Briceno-Mena, Christopher G. Arges, Revati Kumar, Jose A. Romagnoli Jun 2023

Determining Ion Activity Coefficients In Ion-Exchange Membranes With Machine Learning And Molecular Dynamics Simulations, Hishara Keshani Gallage Dona, Teslim Olayiwola, Luis A. Briceno-Mena, Christopher G. Arges, Revati Kumar, Jose A. Romagnoli

Faculty Publications

The activity coefficients of ions in polymeric ion-exchange membranes (IEMs) dictate the equilibrium partitioning coefficient of the ions between the membrane and the liquid. It also affects ion transport processes, such as conductivity, in ion-exchange membranes. Accurately predicting the ion activity coefficient without experimental data has been elusive as most models are empirical or semi-empirical. This work employs an embedding process that maps microscopic and macroscopic properties for modeling of ion activity coefficients in IEMs with molecular dynamics (MD) and machine learning (ML). This strategy is effective for accurately predicting activity coefficients in various IEM materials, including random copolymer and …

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Marine Anoxia Initiates Giant Sulfur-Bacteria Mat Proliferation And Associated Changes In Benthic Nitrogen, Sulfur, And Iron Cycling In The Santa Barbara Basin, California Borderland, David J. Yousavich, De'marcus Robinson, Xuefeng Peng, Sebastian J.E. Krause, Frank Wenzhoefer, Felix Janßen, Na Liu, Jonathan Tarn, Frank Kinnaman, David L. Valentine, Tina Treude Jun 2023

Marine Anoxia Initiates Giant Sulfur-Bacteria Mat Proliferation And Associated Changes In Benthic Nitrogen, Sulfur, And Iron Cycling In The Santa Barbara Basin, California Borderland, David J. Yousavich, De'marcus Robinson, Xuefeng Peng, Sebastian J.E. Krause, Frank Wenzhoefer, Felix Janßen, Na Liu, Jonathan Tarn, Frank Kinnaman, David L. Valentine, Tina Treude

Faculty Publications

The Santa Barbara Basin naturally experiences transient deoxygenation due to its unique geological setting in the southern California Borderland and seasonal changes in ocean currents. Long-term measurements of the basin showed that anoxic events and subsequent nitrate exhaustion in the bottom waters have been occurring more frequently and lasting longer over the past decade. One characteristic of the Santa Barbara Basin is the seasonal development of extensive mats of benthic nitrate-reducing sulfur-oxidizing bacteria, which are found at the sediment–water interface when the basin's bottom waters reach anoxia but still provide some nitrate. To assess the mat's impact on the benthic …

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Investigation Of Iron(Iii) Tetraphenylporphyrin As A Redox Flow Battery Anolyte: Unexpected Side Reactivity With The Electrolyte, Nathan H. Mitchell, Noémie Elgrishi Jun 2023

Investigation Of Iron(Iii) Tetraphenylporphyrin As A Redox Flow Battery Anolyte: Unexpected Side Reactivity With The Electrolyte, Nathan H. Mitchell, Noémie Elgrishi

Faculty Publications

Redox flow batteries (RFBs) present an opportunity to bridge the gap between the intermittent availability of green energy sources and the need for on-demand grid level energy storage. While aqueous vanadium-based redox flow batteries have been commercialized, they are limited by the constraints of using water as an electrochemical solvent. Nonaqueous redox flow battery systems can be used to produce high voltage batteries due to the larger electrochemical window in nonaqueous solvents and the ability to tune the redox properties of active materials through functionalization. Iron porphyrins, a class of organometallic macrocycles, have been the subject of many studies for …

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Cr-Containing Diamond-Like Carbon Coatings Deposited On 316 Stainless Steel Substrates: Characterization And Interfacial Fracture Toughness Measurements, N. J. Anderson, Bin Zhang, A. C. Meng, Xiaoman Zhang, K. P. Lijesh, M. M. Khonsari, W. J. Meng Jun 2023

Cr-Containing Diamond-Like Carbon Coatings Deposited On 316 Stainless Steel Substrates: Characterization And Interfacial Fracture Toughness Measurements, N. J. Anderson, Bin Zhang, A. C. Meng, Xiaoman Zhang, K. P. Lijesh, M. M. Khonsari, W. J. Meng

Faculty Publications

A series of Cr-containing hydrogenated amorphous carbon (a-C:H:Cr) coatings were deposited onto 316 stainless steel (316SS) substrates using inductively coupled plasma assisted reactive sputter deposition. Elemental Cr interlayers with different thicknesses of 100, 200, and 300 nm were deposited between a-C:H:Cr and 316SS. Detailed composition, structure, and mechanical behavior characterization of deposited a-C:H:Cr/Cr/316SS specimens were performed. Fracture toughness values of the a-C:H:Cr layer, the Cr layer, and the a-C:H:Cr/Cr/316SS interfacial regions were measured by bending of microcantilever beams with focused ion beam milled pre-notches in-situ a scanning electron microscope. Measured fracture toughness of a-C:H:Cr/Cr/316SS interfacial regions exhibits an approximately linear …

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Active Colloids As Models, Materials, And Machines, Kyle J.M. Bishop, Sibani Lisa Biswal, Bhuvnesh Bharti Jun 2023

Active Colloids As Models, Materials, And Machines, Kyle J.M. Bishop, Sibani Lisa Biswal, Bhuvnesh Bharti

Faculty Publications

Active colloids use energy input at the particle level to propel persistent motion and direct dynamic assemblies. We consider three types of colloids animated by chemical reactions, time-varying magnetic fields, and electric currents. For each type, we review the basic propulsion mechanisms at the particle level and discuss their consequences for collective behaviors in particle ensembles. These microscopic systems provide useful experimental models of nonequilibrium many-body physics in which dissipative currents break time-reversal symmetry. Freed from the constraints of thermodynamic equilibrium, active colloids assemble to form materials that move, reconfigure, heal, and adapt. Colloidal machines based on engineered particles and …

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