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Articles 1111 - 1140 of 3786

Full-Text Articles in Physical Sciences and Mathematics

Lightweight Multilingual Software Analysis, Damian Lyons, Anne Marie Bogar, David Baird Jul 2018

Lightweight Multilingual Software Analysis, Damian Lyons, Anne Marie Bogar, David Baird

Faculty Publications

Large software systems can often be multilingual – that is, software systems are written in more than one language. However, many popular software engineering tools are monolingual by nature. Nonetheless, companies are faced with the need to manage their large, multilingual codebases to address issues with security, efficiency, and quality metrics. This paper presents a novel lightweight approach to multilingual software analysis – MLSA. The approach is modular and focused on efficient static analysis computation for large codebases. One topic is addressed in detail – the generation of multilingual call graphs to identify language boundary problems in multilingual code. The …

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Responses Of Non-Native Earthworms To Experimental Eradication Of Garlic Mustard And Implications For Native Vegetation, Kristina A. Stinson, Serita D. Frey, M. R. Jackson, E. Coates-Connor, Mark A. Anthony, K. Martinez Jul 2018

Responses Of Non-Native Earthworms To Experimental Eradication Of Garlic Mustard And Implications For Native Vegetation, Kristina A. Stinson, Serita D. Frey, M. R. Jackson, E. Coates-Connor, Mark A. Anthony, K. Martinez

Faculty Publications

Recent studies in invasion biology suggest that positive feedback among two or more introduced organisms facilitate establishment within a new range and drive changes in native plant communities. Here, we experimentally tested for relationships between native plants and two non-native organisms invading forest habitats in North America: garlic mustard (Alliaria petiolata, Brassicaceae) and earthworms. In two forested sites, we compared understory vegetation and earthworm biomass in plots where garlic mustard was removed for three years, plots without garlic mustard invasion, and plots invaded by garlic mustard that was not removed. Earthworm biomass was highest in the plots with garlic mustard, …

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Unraveling Substituent Effects On The Glass Transition Temperatures Of Biorenewable Polyesters, Xiaopeng Yu, Junteng Jia, Shu Xu, Ka Un Lao, Maria J. Sanford, Ramesh K. Ramakrishnan, Sergei I. Nazarenko, Thomas R. Hoye, Geoffrey W. Coates, Robert A. Distasio Jr. Jul 2018

Unraveling Substituent Effects On The Glass Transition Temperatures Of Biorenewable Polyesters, Xiaopeng Yu, Junteng Jia, Shu Xu, Ka Un Lao, Maria J. Sanford, Ramesh K. Ramakrishnan, Sergei I. Nazarenko, Thomas R. Hoye, Geoffrey W. Coates, Robert A. Distasio Jr.

Faculty Publications

Converting biomass-based feedstocks into polymers not only reduces our reliance on fossil fuels, but also furnishes multiple opportunities to design biorenewable polymers with targeted properties and functionalities. Here we report a series of high glass transition temperature (Tg up to 184 °C) polyesters derived from sugar-based furan derivatives as well as a joint experimental and theoretical study of substituent effects on their thermal properties. Surprisingly, we find that polymers with moderate steric hindrance exhibit the highest Tg values. Through a detailed Ramachandran-type analysis of the rotational flexibility of the polymer backbone, we find that additional steric hindrance does …

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Large And Realistic Models Of Amorphous Silicon, Dale Ingram, Bishal Bhattarai, Parthapratim Biswas, David A. Drabold Jul 2018

Large And Realistic Models Of Amorphous Silicon, Dale Ingram, Bishal Bhattarai, Parthapratim Biswas, David A. Drabold

Faculty Publications

Amorphous silicon (a-Si) models are analyzed for structural, electronic and vibrational characteristics. Several models of various sizes have been computationally fabricated for this analysis. It is shown that a recently developed structural modeling algorithm known as force-enhanced atomic refinement (FEAR) provides results in agreement with experimental neutron and X-ray diffraction data while producing a total energy below conventional schemes. We also show that a large model (∼ 500 atoms) and a complete basis is necessary to properly describe vibrational and thermal properties. We compute the density for a-Si, and compare with experimental results.

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An Ensemble Stacked Convolutional Neural Network Model For Environmental Event Sound Recognition, Shaobo Li, Yong Yao, Jie Hu, Guokai Liu, Xuemei Yao, Jianjun Hu Jul 2018

An Ensemble Stacked Convolutional Neural Network Model For Environmental Event Sound Recognition, Shaobo Li, Yong Yao, Jie Hu, Guokai Liu, Xuemei Yao, Jianjun Hu

Faculty Publications

Convolutional neural networks (CNNs) with log-mel audio representation and CNN-based end-to-end learning have both been used for environmental event sound recognition (ESC). However, log-mel features can be complemented by features learned from the raw audio waveform with an effective fusion method. In this paper, we first propose a novel stacked CNN model with multiple convolutional layers of decreasing filter sizes to improve the performance of CNN models with either log-mel feature input or raw waveform input. These two models are then combined using the Dempster–Shafer (DS) evidence theory to build the ensemble DS-CNN model for ESC. Our experiments over three …

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Evolving Paradigms In Biological Carbon Cycling In The Ocean, Chuanlun Zhang, Hongyue Dang, Farooq Azam, Ronald Benner, Louis Legendre, Uta Passow, Luca Polimene, Carol Robinson, Curtis A. Suttle, Nianzhi Jiao Jul 2018

Evolving Paradigms In Biological Carbon Cycling In The Ocean, Chuanlun Zhang, Hongyue Dang, Farooq Azam, Ronald Benner, Louis Legendre, Uta Passow, Luca Polimene, Carol Robinson, Curtis A. Suttle, Nianzhi Jiao

Faculty Publications

Carbon is a keystone element in global biogeochemical cycles. It plays a fundamental role in biotic and abiotic processes in the ocean, which intertwine to mediate the chemistry and redox status of carbon in the ocean and the atmosphere. The interactions between abiotic and biogenic carbon (e.g. CO2, CaCO3, organic matter) in the ocean are complex, and there is a half-century-old enigma about the existence of a huge reservoir of recalcitrant dissolved organic carbon (RDOC) that equates to the magnitude of the pool of atmospheric CO2. The concepts of the biological carbon pump (BCP) …

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A 3.5 Million Solar Masses Black Hole In The Centre Of The Ultracompact Dwarf Galaxy Fornax Ucd3, Anton Afanasiev, Igor Chilingarian, Steffen Mieske, Karina Voggel, Arianna Picotti, Michael Hilker, Anil Seth, Nadine Neumayer, Matthias Frank, Aaron Romanowsky, George Hau, Holger Baumgardt, Christopher Ahn, Jay Strader, Mark Den Brok, Richard Mcdermid, Lee Spitler, Jean Brodie, Jonelle Walsh Jul 2018

A 3.5 Million Solar Masses Black Hole In The Centre Of The Ultracompact Dwarf Galaxy Fornax Ucd3, Anton Afanasiev, Igor Chilingarian, Steffen Mieske, Karina Voggel, Arianna Picotti, Michael Hilker, Anil Seth, Nadine Neumayer, Matthias Frank, Aaron Romanowsky, George Hau, Holger Baumgardt, Christopher Ahn, Jay Strader, Mark Den Brok, Richard Mcdermid, Lee Spitler, Jean Brodie, Jonelle Walsh

Faculty Publications

The origin of ultracompact dwarfs (UCDs), a class of compact stellar systems discovered two decades ago, still remains a matter of debate. Recent discoveries of central supermassive black holes in UCDs likely inherited from their massive progenitor galaxies provide support for the tidal stripping hypothesis. At the same time, on statistical grounds, some massive UCDs might be representatives of the high luminosity tail of the globular cluster luminosity function. Here we present a detection of a 3.3+1.4−1.2×106M⊙ black hole (1σ uncertainty) in the centre of the UCD3 galaxy in the Fornax cluster, which corresponds to 4 per cent of its …

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Securing Zigbee Commercial Communications Using Constellation Based Distinct Native Attribute Fingerprinting, Christopher M. Rondeau, J. Addison Betances, Michael A. Temple Jul 2018

Securing Zigbee Commercial Communications Using Constellation Based Distinct Native Attribute Fingerprinting, Christopher M. Rondeau, J. Addison Betances, Michael A. Temple

Faculty Publications

This work provides development of Constellation Based DNA (CB-DNA) Fingerprinting for use in systems employing quadrature modulations and includes network protection demonstrations for ZigBee offset quadrature phase shift keying modulation. Results are based on 120 unique networks comprised of seven authorized ZigBee RZSUBSTICK devices, with three additional like-model devices serving as unauthorized rogue devices. Authorized network device fingerprints are used to train a Multiple Discriminant Analysis (MDA) classifier and Rogue Rejection Rate (RRR) estimated for 2520 attacks involving rogue devices presenting themselves as authorized devices. With MDA training thresholds set to achieve a True Verification Rate (TVR) of TVR = …

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Litter Identity Affects Assimilation Of Carbon And Nitrogen By A Shredding Caddisfly, Adam C. Siders, Zacchaeus G. Compson, Bruce A. Hungate, Paul Dijkstra, George W. Koch, Adam S. Wymore, A. Stuart Grandy, Jane C. Marks Jul 2018

Litter Identity Affects Assimilation Of Carbon And Nitrogen By A Shredding Caddisfly, Adam C. Siders, Zacchaeus G. Compson, Bruce A. Hungate, Paul Dijkstra, George W. Koch, Adam S. Wymore, A. Stuart Grandy, Jane C. Marks

Faculty Publications

Ecologists often equate litter quality with decomposition rate. In soil and sediments, litter that is rapidly decomposed by microbes often has low concentrations of tannin and lignin and low C:N ratios. Do these same traits also favor element transfer to higher trophic levels in streams, where many insects depend on litter as their primary food source? We test the hypothesis that slow decomposition rates promote element transfer from litter to insects, whereas rapid decomposition favors microbes. We measured carbon and nitrogen fluxes from four plant species to a leaf-shredding caddisfly using isotopically labeled litter. Caddisflies assimilated a higher percentage of …

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An Implementation Strategy To Quantify The Marine Microbial Carbon Pump And Its Sensitivity To Global Change, Carol Robinson, Douglas Wallace, Jung-Ho Hyun, Luca Polimene, Ronald Benner, Yao Zhang, Ruanhong Cai, Rui Zhang, Nianzhi Jiao Jul 2018

An Implementation Strategy To Quantify The Marine Microbial Carbon Pump And Its Sensitivity To Global Change, Carol Robinson, Douglas Wallace, Jung-Ho Hyun, Luca Polimene, Ronald Benner, Yao Zhang, Ruanhong Cai, Rui Zhang, Nianzhi Jiao

Faculty Publications

No abstract provided.

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Commentary: Plastic Waste Associated With Disease On Coral Reefs, Gorka Bidegain, Ika Paul-Pont Jul 2018

Commentary: Plastic Waste Associated With Disease On Coral Reefs, Gorka Bidegain, Ika Paul-Pont

Faculty Publications

No abstract provided.

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Lightweight Multilingual Software Analysis, Damian Lyons, Anne Marie Bogar, David Baird Jul 2018

Lightweight Multilingual Software Analysis, Damian Lyons, Anne Marie Bogar, David Baird

Faculty Publications

Developer preferences, language capabilities and the persistence of older languages contribute to the trend that large software codebases are often multilingual – that is, written in more than one computer language. While developers can leverage monolingual software development tools to build software components, companies are faced with the problem of managing the resultant large, multilingual codebases to address issues with security, efficiency, and quality metrics. The key challenge is to address the opaque nature of the language interoperability interface: one language calling procedures in a second (which may call a third, or even back to the first), resulting in a …

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Arrhenius Rate Chemistry-Informed Inter-Phase Source Terms (Arciist), Matthew J. Schwaab, Robert B. Greendyke, Bryan J. Steward Jul 2018

Arrhenius Rate Chemistry-Informed Inter-Phase Source Terms (Arciist), Matthew J. Schwaab, Robert B. Greendyke, Bryan J. Steward

Faculty Publications

Currently, in macro-scale hydrocodes designed to simulate explosive material undergoing shock-induced ignition, the state of the art is to use one of numerous reaction burn rate models. These burn models are designed to estimate the bulk chemical reaction rate. Unfortunately, these burn rate models are largely based on empirical data and must be recalibrated for every new material being simulated. We propose that the use of Arrhenius Rate Chemistry-Informed Interphase Source Terms (ARCIIST) in place of empirically derived burn models will improve the accuracy for these computational codes. A reacting chemistry model of this form was developed for the cyclic …

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Cybersecurity Architectural Analysis For Complex Cyber-Physical Systems, Martin Trae Span Iii, Logan O. Mailloux, Michael R. Grimaila Jul 2018

Cybersecurity Architectural Analysis For Complex Cyber-Physical Systems, Martin Trae Span Iii, Logan O. Mailloux, Michael R. Grimaila

Faculty Publications

In the modern military’s highly interconnected and technology-reliant operational environment, cybersecurity is rapidly growing in importance. Moreover, as a number of highly publicized attacks have occurred against complex cyber-physical systems such as automobiles and airplanes, cybersecurity is no longer limited to traditional computer systems and IT networks. While architectural analysis approaches are critical to improving cybersecurity, these approaches are often poorly understood and applied in ad hoc fashion. This work addresses these gaps by answering the questions: 1. “What is cybersecurity architectural analysis?” and 2. “How can architectural analysis be used to more effectively support cybersecurity decision making for complex …

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A Building Permit System For Smart Cities: A Cloud-Based Framework, Magdalini Eirinaki, Subhankar Dhar, Shishir Mathur, Adwait Kaley, Arpit Patel, Akshar Joshi, Dhvani Shah Jul 2018

A Building Permit System For Smart Cities: A Cloud-Based Framework, Magdalini Eirinaki, Subhankar Dhar, Shishir Mathur, Adwait Kaley, Arpit Patel, Akshar Joshi, Dhvani Shah

Faculty Publications

In this paper we propose a novel, cloud-based framework to support citizens and city officials in the building permit process. The proposed framework is efficient, user-friendly, and transparent with a quick turn-around time for homeowners. Compared to existing permit systems, the proposed smart city permit framework provides a pre-permitting decision workflow, and incorporates a data analytics and mining module that enables the continuous improvement of both the end user experience and the permitting and urban planning processes. This is enabled through a data mining-powered permit recommendation engine as well as a data analytics process that allow a gleaning of key …

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On The Approximation Of The Inverse Error Covariances Of High-Resolution Satellite Altimetry Data, Max Yaremchuk, Joseph M. D'Addezio, Gleb Panteleev, Gregg Jacobs Jul 2018

On The Approximation Of The Inverse Error Covariances Of High-Resolution Satellite Altimetry Data, Max Yaremchuk, Joseph M. D'Addezio, Gleb Panteleev, Gregg Jacobs

Faculty Publications

© 2018 Royal Meteorological Society High-resolution (swath) altimeter missions scheduled to monitor the ocean surface in the near future have observation-error covariances (OECs) with slowly decaying off-diagonal elements. This property presents a challenge for the majority of the data assimilation algorithms which were designed under the assumption of the diagonal OECs being easily inverted. In this note, we present a method of approximating the inverse of a dense OEC by a sparse matrix represented by the polynomial of spatially inhomogeneous differential operators, whose coefficients are optimized to fit the target OEC by minimizing a quadratic cost function. Explicit expressions for …

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The Impact Of The Deepwater Horizon Blowout On Historic Shipwreck-Associated Sediment Microbiomes In The Northern Gulf Of Mexico, Leila J. Hamdan, Jennifer Salerno, Allen H. Reed, Samantha B. Joye, Melanie Damour Jun 2018

The Impact Of The Deepwater Horizon Blowout On Historic Shipwreck-Associated Sediment Microbiomes In The Northern Gulf Of Mexico, Leila J. Hamdan, Jennifer Salerno, Allen H. Reed, Samantha B. Joye, Melanie Damour

Faculty Publications

More than 2,000 historic shipwrecks spanning 500 years of history, rest on the Gulf of Mexico seafloor. Shipwrecks serve as artificial reefs and hotspots of biodiversity by providing hard substrate, something rare in deep ocean regions. The Deepwater Horizon (DWH) spill discharged crude oil into the deep Gulf. Because of physical, biological, and chemical interactions, DWH oil was deposited on the seafloor, where historic shipwrecks are present. This study examined sediment microbiomes at seven historic shipwrecks. Steel-hulled, World War II-era shipwrecks and wooden-hulled, 19th century shipwrecks within and outside of the surface oiled area and subsurface plume were examined. Analysis …

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Seasonal Patterns In Phytoplankton Biomass Across The Northern And Deep Gulf Of Mexico: A Numerical Model Study, Fabian A. Gomez, Sang-Ki Lee, Yanyun Liu, Frank J. Hernandez Jr., Frank E. Muller-Karger, John T. Lamkin Jun 2018

Seasonal Patterns In Phytoplankton Biomass Across The Northern And Deep Gulf Of Mexico: A Numerical Model Study, Fabian A. Gomez, Sang-Ki Lee, Yanyun Liu, Frank J. Hernandez Jr., Frank E. Muller-Karger, John T. Lamkin

Faculty Publications

Biogeochemical models that simulate realistic lower-trophic-level dynamics, including the representation of main phytoplankton and zooplankton functional groups, are valuable tools for improving our understanding of natural and anthropogenic disturbances in marine ecosystems. Previous three-dimensional biogeochemical modeling studies in the northern and deep Gulf of Mexico (GoM) have used only one phytoplankton and one zooplankton type. To advance our modeling capability of the GoM ecosystem and to investigate the dominant spatial and seasonal patterns of phytoplankton biomass, we configured a 13-component biogeochemical model that explicitly represents nanophytoplankton, diatoms, micro-, and mesozooplankton. Our model outputs compare reasonably well with observed patterns in …

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Minerals In The Rhizosphere: Overlooked Mediators Of Soil Nitrogen Availability To Plants And Microbes, Andrea Jilling, Marco Keiluweit, Alexandra R. Contosta, Serita D. Frey, Joshua Schimel, Jorg Schnecker, Richard G. Smith, Lisa Tiemann, A. Stuart Grandy Jun 2018

Minerals In The Rhizosphere: Overlooked Mediators Of Soil Nitrogen Availability To Plants And Microbes, Andrea Jilling, Marco Keiluweit, Alexandra R. Contosta, Serita D. Frey, Joshua Schimel, Jorg Schnecker, Richard G. Smith, Lisa Tiemann, A. Stuart Grandy

Faculty Publications

Despite decades of research progress, ecologists are still debating which pools and fluxes provide nitrogen (N) to plants and soil microbes across different ecosystems. Depolymerization of soil organic N is recognized as the rate-limiting step in the production of bioavailable N, and it is generally assumed that detrital N is the main source. However, in many mineral soils, detrital polymers constitute a minor fraction of total soil organic N. The majority of organic N is associated with clay-sized particles where physicochemical interactions may limit the accessibility of N-containing compounds. Although mineral-associated organic matter (MAOM) has historically been considered a critical, …

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Enabling Autonomous Navigation For Affordable Scooters, Kaikai Liu, Rajathswaroop Mulky Jun 2018

Enabling Autonomous Navigation For Affordable Scooters, Kaikai Liu, Rajathswaroop Mulky

Faculty Publications

Despite the technical success of existing assistive technologies, for example, electric wheelchairs and scooters, they are still far from effective enough in helping those in need navigate to their destinations in a hassle-free manner. In this paper, we propose to improve the safety and autonomy of navigation by designing a cutting-edge autonomous scooter, thus allowing people with mobility challenges to ambulate independently and safely in possibly unfamiliar surroundings. We focus on indoor navigation scenarios for the autonomous scooter where the current location, maps, and nearby obstacles are unknown. To achieve semi-LiDAR functionality, we leverage the gyros-based pose data to compensate …

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Applied Computing For Behavioral And Social Sciences (Acbss) Minor, Farshid Marbouti, Valerie Carr, Belle Wei, Morris Jones, Amy Strage Jun 2018

Applied Computing For Behavioral And Social Sciences (Acbss) Minor, Farshid Marbouti, Valerie Carr, Belle Wei, Morris Jones, Amy Strage

Faculty Publications

The growing digital economy creates unprecedented demand for technical workers, especially those with both domain knowledge and technical skills. To meet this need, an ACBSS (Applied Computing for Behavioral and Social Sciences) minor degree has been developed by an interdisciplinary team of faculty at San José State University (SJSU). The minor degree comprises four courses: Python programming, algorithms and data structures, R programming, and culminating projects. The first ACBSS cohort started in Fall 2016 with 32 students, and the second cohort in Fall 2017 reached its capacity of 40 students, 62% of whom are female and 35% are underrepresented minority …

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The Sluggs Survey: A Comparison Of Total-Mass Profiles Of Early-Type Galaxies From Observations And Cosmological Simulations, To ∼4 Effective Radii, Sabine Bellstedt, Duncan Forbes, Aaron Romanowsky, Rhea-Silvia Remus, Adam Stevens, Jean Brodie, Adriano Poci, Richard Mcdermid, Adebusola Alabi, Leonie Chevalier, Caitlin Adams, Anna Ferré-Mateu, Asher Wasserman, Viraj Pandya Jun 2018

The Sluggs Survey: A Comparison Of Total-Mass Profiles Of Early-Type Galaxies From Observations And Cosmological Simulations, To ∼4 Effective Radii, Sabine Bellstedt, Duncan Forbes, Aaron Romanowsky, Rhea-Silvia Remus, Adam Stevens, Jean Brodie, Adriano Poci, Richard Mcdermid, Adebusola Alabi, Leonie Chevalier, Caitlin Adams, Anna Ferré-Mateu, Asher Wasserman, Viraj Pandya

Faculty Publications

We apply the Jeans Anisotropic Multi-Gaussian Expansion dynamical modelling method to SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey data of early-type galaxies in the stellar mass range 1010 < M*/M⊙ < 1011.6 that cover a large radial range of 0.1–4.0 effective radii. We combine SLUGGS and ATLAS3D data sets to model the total-mass profiles of a sample of 21 fast-rotator galaxies, utilizing a hyperparameter method to combine the two independent data sets. The total-mass density profile slope values derived for these galaxies are consistent with those measured in the inner regions of galaxies by other studies. Furthermore, the total-mass density slopes (γtot) appear to be universal over this broad stellar mass range, with an average value of γtot =  −2.24 ±  0.05 , i.e. slightly steeper than isothermal. We compare our results to model galaxies from the Magneticum and EAGLE cosmological hydrodynamic simulations, in order to probe the mechanisms that are responsible for varying total-mass density profile slopes. The simulated-galaxy slopes are shallower than the observed values by ∼0.3–0.5, indicating that the physical processes shaping the mass distributions of galaxies in cosmological simulations are still incomplete. For galaxies with M* > 1010.7 M⊙ in the Magneticum simulations, we identify a significant anticorrelation between total-mass density profile slopes and the fraction of stellar mass formed ex situ (i.e. accreted), whereas this anticorrelation is weaker for lower stellar masses, implying that the measured total-mass density slopes for low-mass galaxies are less likely to be determined by merger activity.

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Contribution Of Hi-Bearing Ultra-Diffuse Galaxies To The Cosmic Number Density Of Galaxies, M. Jones, E. Papastergis, V. Pandya, L. Leisman, Aaron J. Romanowsky, L. Yung, R. Somerville, E. Adams Jun 2018

Contribution Of Hi-Bearing Ultra-Diffuse Galaxies To The Cosmic Number Density Of Galaxies, M. Jones, E. Papastergis, V. Pandya, L. Leisman, Aaron J. Romanowsky, L. Yung, R. Somerville, E. Adams

Faculty Publications

We estimate the cosmic number density of the recently identified class of HI-bearing ultra-diffuse sources (HUDs) based on the completeness limits of the ALFALFA survey. These objects have HI masses approximately in the range 8.5 < logMHI∕M⊙ < 9.5, average r-band surface brightnesses fainter than 24 mag arcsec−2, half-light radii greater than 1.5 kpc, and are separated from neighbours by at least 350 kpc. In this work we demonstrate that they contribute at most ~6% of the population of HI-bearing dwarfs detected by ALFALFA (with similar HI masses), have a total cosmic number density of (1.5 ± 0.6) × 10−3 …

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Facially Amphiphilic Polyionene Biocidal Polymers Derived From Lithocholic Acid, Mitra S. Ganewatta, Md Anisur Rahman, Louis Mercado, Tinom Shokfai, Alan W. Decho, Theresa M. Reineke, Chuanbing Tang Jun 2018

Facially Amphiphilic Polyionene Biocidal Polymers Derived From Lithocholic Acid, Mitra S. Ganewatta, Md Anisur Rahman, Louis Mercado, Tinom Shokfai, Alan W. Decho, Theresa M. Reineke, Chuanbing Tang

Faculty Publications

Bacterial infections have become a global issue that requires urgent attention, particularly regarding to emergence of multidrug resistant bacteria. We developed quaternary amine-containing antimicrobial poly(bile acid)s that contain a hydrophobic core of lithocholic acid in the main-chain. Interestingly, by choosing appropriate monomers, these cationic polymers can form core-shell micelles. These polymers exhibited biocidal activity against both Gram-positive and Gram-negative bacterial species. It is demonstrated that the micelles can deliver hydrophobic antibiotics that functionally have dual antimicrobial activities. Cytotoxicity assays against HeLa cells showed dosage-dependent toxicity for polymers with longer linkers.

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Identifying Prevalent Mathematical Pathways To Engineering In South Carolina, Eliza Gallagher, Christy Brown, D. Andrew Brown, Kristin Kelly Frady, Patrick Bass, Michael A. Matthews, Thomas T. Peters, Robert J. Rabb, Ikhalfani Solan, Ronald W. Welch, Anand K. Gramopadhye Jun 2018

Identifying Prevalent Mathematical Pathways To Engineering In South Carolina, Eliza Gallagher, Christy Brown, D. Andrew Brown, Kristin Kelly Frady, Patrick Bass, Michael A. Matthews, Thomas T. Peters, Robert J. Rabb, Ikhalfani Solan, Ronald W. Welch, Anand K. Gramopadhye

Faculty Publications

National data indicate that initial mathematics course placement in college is a strong predictor of persistence to degree in engineering, with students placed in calculus persisting at nearly twice the rate of those placed below calculus. Within the state of South Carolina, approximately 95% of engineering-intending students who initially place below calculus are from in-state. In order to make systemic change, we are first analyzing system-wide data to identify prevalent educational pathways within the state, and the mathematical milestones along those pathways taken by students in engineering and engineering-related fields. This paper reports preliminary analysis of that data to understand …

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Assessing Relevance Of Tweets For Risk Communication, Xiaohui Liu, Bandana Kar, Chaoyang Zhang, David M. Cochran Jun 2018

Assessing Relevance Of Tweets For Risk Communication, Xiaohui Liu, Bandana Kar, Chaoyang Zhang, David M. Cochran

Faculty Publications

Although Twitter is used for emergency management activities, the relevance of tweets during a hazard event is still open to debate. In this study, six different computational (i.e. Natural Language Processing) and spatiotemporal analytical approaches were implemented to assess the relevance of risk information extracted from tweets obtained during the 2013 Colorado flood event. Primarily, tweets containing information about the flooding events and its impacts were analysed. Examination of the relationships between tweet volume and its content with precipitation amount, damage extent, and official reports revealed that relevant tweets provided information about the event and its impacts rather than any …

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The Method Of Particular Solutions Using Trigonometric Basis Functions, Zhaolu Tian, Xinxiang Li, C.M. Fan, Ching-Shyang Chen Jun 2018

The Method Of Particular Solutions Using Trigonometric Basis Functions, Zhaolu Tian, Xinxiang Li, C.M. Fan, Ching-Shyang Chen

Faculty Publications

In this paper, the method of particular solutions (MPS) using trigonometric functions as the basis functions is proposed to solve two-dimensional elliptic partial differential equations. The inhomogeneous term of the governing equation is approximated by Fourier series and the closed-form particular solutions of trigonometric functions are derived using the method of undetermined coefficients. Once the particular solutions for the trigonometric basis functions are derived, the standard MPS can be applied for solving partial differential equations. In comparing with the use of radial basis functions and polynomials in the MPS, our proposed approach provides another simple approach to effectively solving two-dimensional …

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Photovoltaic System Optimization For An Austere Location Using Time Series Data, Torrey J. Wagner, Eric Lang, Warren Assink, Douglas S. Dudis Jun 2018

Photovoltaic System Optimization For An Austere Location Using Time Series Data, Torrey J. Wagner, Eric Lang, Warren Assink, Douglas S. Dudis

Faculty Publications

In this work we test experimental photovoltaic, storage and generator technologies and investigate their potential to meet austere location energy needs. After defining the energy requirements and insolation of a 1,100-person base, we develop a microgrid model and simulation. Cost optimizations were then performed using hourly time-series data to explore the cost and performance trade-space of a PV-battery-generator system. The work highlights the cost of resiliency and the dependencies of optimum system component sizes on duration and the fully burdened cost of fuel.

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Isotopic Composition Of Sinking Particles: Oil Effects, Recovery And Baselines In The Gulf Of Mexico, 2010-2015, Jeff Chanton, Sarah L.C. Giering, Samantha H. Bosman, Kelsey L. Rogers, Julia Sweet, Vernon Asper, Arne-R. Diercks, Uta Passow May 2018

Isotopic Composition Of Sinking Particles: Oil Effects, Recovery And Baselines In The Gulf Of Mexico, 2010-2015, Jeff Chanton, Sarah L.C. Giering, Samantha H. Bosman, Kelsey L. Rogers, Julia Sweet, Vernon Asper, Arne-R. Diercks, Uta Passow

Faculty Publications

The extensive release of oil during the 2010 Deepwater Horizon spill in the northern Gulf of Mexico perturbed the pelagic ecosystem and associated sinking material. To gauge the recovery and post-spill baseline sources, we measured D14C, d13C and d34S of sinking particles near the spill site and at a reference site and natural seep site. Particulates were collected August 2010–April 2016 in sediment traps moored at sites with depths of 1160–1660 m. Near the spill site, changes in D14C indicated a 3-year recovery period, while d34S indicated 1–2 years, which agreed with estimates of 1–2 years based on hydrocarbon composition. …

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Nearly Defect-Free Dynamical Models Of Disordered Solids: The Case Of Amorphous Silicon, Raymond Atta-Fynn, Parthapratim Biswas May 2018

Nearly Defect-Free Dynamical Models Of Disordered Solids: The Case Of Amorphous Silicon, Raymond Atta-Fynn, Parthapratim Biswas

Faculty Publications

It is widely accepted in the materials modeling community that defect-free realistic networks of amorphous silicon cannot be prepared by quenching from a molten state of silicon using classical or ab initio molecular-dynamics (MD) simulations. In this work, we address this long-standing problem by producing nearly defect-free ultra-large models of amorphous silicon, consisting of up to half a million atoms, using classical MD simulations. The structural, topological, electronic, and vibrational properties of the models are presented and compared with experimental data. A comparison of the models with those obtained from using the modified Wooten-Winer-Weaire bond-switching algorithm shows that the models …

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