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University of Texas Rio Grande Valley

2018

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Articles 31 - 60 of 113

Full-Text Articles in Physical Sciences and Mathematics

Particulate Metal Exposures Induce Plasma Metabolome Changes In A Commuter Panel Study, Chandresh N. Ladva, Rachel Golan, Donghai Liang, Roby Greenwald, Douglas I. Walker, Amit U. Raysoni, Vilinh Tran, Tianwei Yu, W. Dana Flanders, Gary W. Miller Sep 2018

Particulate Metal Exposures Induce Plasma Metabolome Changes In A Commuter Panel Study, Chandresh N. Ladva, Rachel Golan, Donghai Liang, Roby Greenwald, Douglas I. Walker, Amit U. Raysoni, Vilinh Tran, Tianwei Yu, W. Dana Flanders, Gary W. Miller

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Introduction

Advances in liquid chromatography-mass spectrometry (LC-MS) have enabled high-resolution metabolomics (HRM) to emerge as a sensitive tool for measuring environmental exposures and corresponding biological response. Using measurements collected as part of a large, panel-based study of car commuters, the current analysis examines in-vehicle air pollution concentrations, targeted inflammatory biomarker levels, and metabolomic profiles to trace potential metabolic perturbations associated with on-road traffic exposures.

Methods

A 60-person panel of adults participated in a crossover study, where each participant conducted a highway commute and randomized to either a side-street commute or clinic exposure session. In addition to in-vehicle exposure characterizations, participants …


Development Of Hurricane Storm Surge Model To Predict Coastal Highway Inundation For South Texas, Sara E. Davila, Adan Garza, Jungseok Ho Sep 2018

Development Of Hurricane Storm Surge Model To Predict Coastal Highway Inundation For South Texas, Sara E. Davila, Adan Garza, Jungseok Ho

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Forecasting areas prone to flooding will allow us to send off our information gathered to departments such as TxDOT and the United States Department of Transportation. This would then enable these departments to create appropriate evacuation routes, depicting which roads are clear and which cannot be used in the event of a storm. Simulating hurricanes that have passed through this area such as Dolly in 2008, Beulah in 1967, and Bret in 1999 will display the roads and federal highways that frequently tend to get flooded. Identifying the “danger roads” and which federal highways will ultimately be useful for various …


Conformational Analysis Of A Taddol-Based Phosphoramidite P,N Ligand In A Palladium(Ii) Η3-Π-Allyl Complex, Tülay A. Ateşin, Abdurrahman Atesin, Oscar Rodriguez, Diego Rivera, Lohany Y. Garcia Sep 2018

Conformational Analysis Of A Taddol-Based Phosphoramidite P,N Ligand In A Palladium(Ii) Η3-Π-Allyl Complex, Tülay A. Ateşin, Abdurrahman Atesin, Oscar Rodriguez, Diego Rivera, Lohany Y. Garcia

Chemistry Faculty Publications and Presentations

Highlights

  • Two lowest energy conformers differ in allyl conformation, conformer with exo allyl having lower energy.
  • Lowest energy conformer has “chair” conformation of 7-membered ring and “edge-on/face-on/face-on/edge-on” array of pH groups.
  • Next lowest energy conformer with exo allyl has alternating “edge-on/face-on” arrangement and “twist” 7-membered ring.
  • Changes in “chair/twist” conformations with different substrates is possible due to 2.4 kcal/mol energy difference.
  • These results explain stereochemical outcome of the reaction, and will guide design of new catalysts.

Abstract

The most stable conformations of a TADDOL-based phosphoramidite P,N ligand coordinated to a palladium(II) η3-π-allyl fragment have been investigated using …


Underwater Adhesive Using Solid–Liquid Polymer Mixes, Alin Cristian Chipara, T. Tsafack, P. S. Owuor, J. Yeon, C. E. Junkermeier, A. C. T. Van Duin, S. Bhowmick, S. A. S. Asif, S. Radhakrishnan, Mircea Chipara Sep 2018

Underwater Adhesive Using Solid–Liquid Polymer Mixes, Alin Cristian Chipara, T. Tsafack, P. S. Owuor, J. Yeon, C. E. Junkermeier, A. C. T. Van Duin, S. Bhowmick, S. A. S. Asif, S. Radhakrishnan, Mircea Chipara

Physics and Astronomy Faculty Publications and Presentations

Instantaneous adhesion between different materials is a requirement for several applications ranging from electronics to biomedicine. Approaches such as surface patterning, chemical cross-linking, surface modification, and chemical synthesis have been adopted to generate temporary adhesion between various materials and surfaces. Because of the lack of curing times, temporary adhesives are instantaneous, a useful property for specific applications that need quick bonding. However, to this day, temporary adhesives have been mainly demonstrated under dry conditions and do not work well in submerged or humid environments. Furthermore, most rely on chemical bonds resulting from strong interactions with the substrate such as acrylate …


Removal Of Cu2+ And Ni2+ From Aqueous Solution Using Sno2 Nanomaterial Effect Of: Ph, Time, Temperature, Interfering Cations, Abigail M. Zepeda, Daisy Gonzalez, Luis Gonzalez Heredia, Karina Marquez, Cesar Perez, Erika Pena, K. Flores, Carolina Valdes, Thomas Eubanks, Jason Parsons, J. Cantu Sep 2018

Removal Of Cu2+ And Ni2+ From Aqueous Solution Using Sno2 Nanomaterial Effect Of: Ph, Time, Temperature, Interfering Cations, Abigail M. Zepeda, Daisy Gonzalez, Luis Gonzalez Heredia, Karina Marquez, Cesar Perez, Erika Pena, K. Flores, Carolina Valdes, Thomas Eubanks, Jason Parsons, J. Cantu

Chemistry Faculty Publications and Presentations

Tin oxide, SnO2, nanomaterial was synthesized and tested for the removal of Cu2+ and Ni2+ ions from aqueous solutions. Various parameters for the binding were investigated in batch studied, which included pH, time, temperature, and interferences. In addition, isotherm studied were performed to determine the maximum binding capacity for both Cu2+ and Ni2+ ions. The optimal binding pH determined from the effects of pH were to be at pH 5 for both the Cu2+ and Ni2+ ions. The isotherm studies were performed at temperatures of 4°C, 25 °C, and 45 °C for both the Cu2+ and Ni2+ ions and were …


Three-Dimensional Carbon Nanotube Yarn Based Solid State Solar Cells With Multiple Sensitizers Exhibit High Energy Conversion Efficiency, Glenn Grissom, Jared Jaksik, Monica Mcentee, Erin M. Durke, Sayeeda Tj Aishee, Margaret Cua, Okenwa Okoli, Ahmed Touhami, H. Justin Moore, M. Jasim Uddin Sep 2018

Three-Dimensional Carbon Nanotube Yarn Based Solid State Solar Cells With Multiple Sensitizers Exhibit High Energy Conversion Efficiency, Glenn Grissom, Jared Jaksik, Monica Mcentee, Erin M. Durke, Sayeeda Tj Aishee, Margaret Cua, Okenwa Okoli, Ahmed Touhami, H. Justin Moore, M. Jasim Uddin

Chemistry Faculty Publications and Presentations

Fiber-type dye sensitized solar cells that are non-metallic, flexible, and thread-like in structure have many potential military and functional textile applications. With the use of quantum dots (QD), exciton transfer facilitators (Phenyl-C61-butyric acid methyl ester-PCBM) and Poly(3-hexylthiophene-2,5-diyl-P3HT), and careful preparation of the TiO2 oxide layer deposited on the carbon fiber working electrode, an optimized efficiency of 7.6% was obtained. Carbon nanotube yarn (CNTY) was used to prepare both the working and counter electrodes of the fabricated cells. TiCl4 annealing of the TiO2 layer was carried out and the resulting oxide layer morphology was found to be very uniform. The quantum …


Solution Of Mathematical Model For Gas Solubility Using Fractional-Order Bhatti Polynomials, Muhammad I. Bhatti, Paul Bracken, Nicholas Dimakis, Armando Herrera Aug 2018

Solution Of Mathematical Model For Gas Solubility Using Fractional-Order Bhatti Polynomials, Muhammad I. Bhatti, Paul Bracken, Nicholas Dimakis, Armando Herrera

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Solutions of a mathematical model for gas solubility in a liquid are attained employing an algorithm based on the generalized Galerkin B-poly basis technique. The algorithm determines a solution of a fractional differential equation in terms of continuous finite number of generalized fractional-order Bhatti polynomial (B-poly) in a closed interval. The procedure uses Galerkin method to calculate the unknown expansion coefficients for constructing a solution to the fractional-order differential equation. Caputo?s fractional derivative is employed to evaluate the derivatives of the fractional B-polys and each term in the differential equation is converted into a matrix problem which is then inverted …


A Formulation Of L-Isothermic Surfaces In Three-Dimensional Minkowski Space, Paul Bracken Aug 2018

A Formulation Of L-Isothermic Surfaces In Three-Dimensional Minkowski Space, Paul Bracken

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

The Cartan structure equations are used to study space-like and time-like isothermic surfaces in three-dimensional Minkowski space in a unified framework. When the lines of curvature of a surface constitute an isothermal system, the surface is called isothermic. This condition serves to define a system of one-forms such that, by means of the structure equations, the Gauss-Codazzi equations for the surface are determined explicitly. A Lax pair can also be obtained from these one-forms for both cases, and, moreover, a nonhomogeneous Schrödinger equation can be associated with the set of space-like surfaces.


Environmental Conditions In San Martin Lake: Effects Of Eutrophication In An Estuary Associated With The Laguna Madre, Wendy L. Rogers Aug 2018

Environmental Conditions In San Martin Lake: Effects Of Eutrophication In An Estuary Associated With The Laguna Madre, Wendy L. Rogers

Theses and Dissertations

San Martin Lake is a shallow water Estuary in the lower Laguna Madre off the Port of Brownsville Shipping channel. It is influenced both by incoming tides and waste water runoff both from local farms and the Brownsville water treatment plants. The resulting mixture of eutrophic water and incoming sea water creates the perfect mix for a potential algal bloom. This study looks at the nutrient levels and environmental conditions in the main basin of the estuary to establish baseline levels and to observe the rate of nutrient clearing being accomplished in this environment. As sport recreation in the area …


Nannochloris Sp. And Oocystis Sp. Algae Exposed To Osmotic Stress For Increased Lipid Production For Use In Biofuels, Laura M. Chavez Aug 2018

Nannochloris Sp. And Oocystis Sp. Algae Exposed To Osmotic Stress For Increased Lipid Production For Use In Biofuels, Laura M. Chavez

Theses and Dissertations

Algal biofuel research is important due to the potential need for replacement of non-renewable fossil fuels and a changing global climate. Under stress, algal cells tend to increase neutral lipid production, which are a suitable source for biofuels. The goal of this study was to subject Nannochloris sp.. and Oocystis sp. algal cells to osmotic stress by modifying sucrose and salinity levels in different treatment medias.

The treatment containing the lowest salinity (15 ppt) and no sucrose yielded the highest lipid fluorescence/cell in Nannochloris sp.. cells (0.00142 ± 0.00044) on day 2 while the treatment containing highest salinity (35ppt) …


Functionalized And Nanostructured Fibers For Photocatalysis And Energy Conversion, Jared R. Jaksik Aug 2018

Functionalized And Nanostructured Fibers For Photocatalysis And Energy Conversion, Jared R. Jaksik

Theses and Dissertations

Fiber-type / flexible materials present a unique opportunity for the incorporation of photocatalytic / energy generating technology, as they typically have a broad surface area exposed to light (clothing, curtains, carpet). In this work, several methods of harvesting incident light striking a flexible substrate to perform useful work are examined. In the first section a gold and silver nanoparticle augmented TiO2 thin film textile coating is evaluated for its self-cleaning / UV-protective / anti-microbial properties, and stability of the film / substrate over time is examined. In the second section a dye sensitized / hybrid type solar cell architecture based …


Characterizing Polychlorinated Biphenyl Degradation Potential In Surface Water Bacteria From Rio Grande Valley, Texas Reservoirs, Alisha M. Janiga Aug 2018

Characterizing Polychlorinated Biphenyl Degradation Potential In Surface Water Bacteria From Rio Grande Valley, Texas Reservoirs, Alisha M. Janiga

Theses and Dissertations

The Donna Reservoir in Donna, Texas is contaminated with polychlorinated biphenyl (PCB) pollution. This reviews the current understanding of PCBs and investigate the potential of PCB degradation by native bacteria communities in the Donna Reservoir. The metabolic diversity, biphenyl tolerance, bphA1 presence were tested on surface water samples from the Donna Reservoir. The Ecoplate data suggest that the communities have a diverse metabolic capacity and the degree of plant life may interact with carbon type metabolism but not the rate of growth. Biphenyl growth curves showed that all the samples from the Donna Reservoir are tolerant to the average PCB …


Glutathione: A Small Molecule With Big Sense, Cristina E. Raya, Debasish Bandyopadhyay Aug 2018

Glutathione: A Small Molecule With Big Sense, Cristina E. Raya, Debasish Bandyopadhyay

Chemistry Faculty Publications and Presentations

Glutathione, a peptide found in microbes, plants and animals including human plays a key role in maintaining healthy cells. The peptide exists in both reduced and oxidized forms. Synthesis of GSH occurs in the cytosol of cells, and the extent of glutathione synthesis relies on various factors, such as amino acid availability, protein activity etc. Once synthesized, glutathione exists in both forms: oxidized (GSSG) and reduced (GSH). Oxidized glutathione characterized by its disulfide linkage. On the other hand, presence of a thiol group characterizes the reduced glutathione. This thiol makes the tripeptide an essential component of health; it makes glutathione …


Effect Of Molten Salt Synthesis Processing Duration On The Photo- And Radioluminescence Of Uv- Visible- And X-Ray-Excitable La 2 Hf 2 O 7 :Eu 3+ Nanoparticles, Jose P. Zuniga, Santosh K. Gupta, Maya Abdou, Yuanbing Mao Jul 2018

Effect Of Molten Salt Synthesis Processing Duration On The Photo- And Radioluminescence Of Uv- Visible- And X-Ray-Excitable La 2 Hf 2 O 7 :Eu 3+ Nanoparticles, Jose P. Zuniga, Santosh K. Gupta, Maya Abdou, Yuanbing Mao

Chemistry Faculty Publications and Presentations

Ln 3+ -ion-doped nanomaterials possess excellent properties because of their high color purity, longer excited state lifetime, narrow emission, and large Stokes shifts. In this work, we studied the correlation between the luminescence properties of La 2 Hf 2 O 7 :Eu 3+ pyrochlore nanoparticles (NPs) synthesized by a molten salt synthesis (MSS) method at a relatively low temperature and several MSS processing durations (from 1 to 12 h). We synthesized these NPs with different sizes just by changing the MSS processing time without subjecting to high temperature. Raman spectroscopy confirmed the stabilization of the ideal pyrochlore structure of the …


Asymmetric Free-Space Light Transport At Nonlinear Metasurfaces, Nir Shitrit, Jeongmin Kim, David S. Barth, Hamidreza Ramezani, Yuan Wang, Xiang Zhang Jul 2018

Asymmetric Free-Space Light Transport At Nonlinear Metasurfaces, Nir Shitrit, Jeongmin Kim, David S. Barth, Hamidreza Ramezani, Yuan Wang, Xiang Zhang

Physics and Astronomy Faculty Publications and Presentations

Asymmetric light transport has significantly contributed to fundamental science and revolutionized advanced technology in various aspects such as unidirectional photonic devices, optical diodes, and isolators. While metasurfaces mold wave fronts at will with an ultrathin flat optical element, asymmetric transport of light cannot be fundamentally achieved by any linear system including linear metasurfaces. We report asymmetric transport of free-space light at nonlinear metasurfaces upon transmission and reflection. Moreover, we theoretically derive the nonlinear generalized Snell's laws that were experimentally confirmed by the anomalous nonlinear refraction and reflection. The asymmetric transport at optically thin nonlinear interfaces is revealed by the concept …


Thermodynamic And Kinetic Study Of The Removal Of Cu2+ And Pb2+ Ions From Aqueous Solution Using Fe7s8 Nanomaterial, Jesus Cantu, Diego F. Gonzalez, Yvette Cantu, Thomas Eubanks, Jason Parsons Jul 2018

Thermodynamic And Kinetic Study Of The Removal Of Cu2+ And Pb2+ Ions From Aqueous Solution Using Fe7s8 Nanomaterial, Jesus Cantu, Diego F. Gonzalez, Yvette Cantu, Thomas Eubanks, Jason Parsons

Chemistry Faculty Publications and Presentations

In the present study, pyrrhotite (Fe7S8) was investigated for the removal of Pb2+ and Cu2+ ions from aqueous solution. The Fe7S8 material was prepared through a solvothermal method and was characterized using XRD. The average particle size for the nanomaterial was determined to be 29.86 ± 0.87 nm using XRD analysis and Scherrer's equation. Batch studies were performed to investigate the effects of pH, time, temperature, interfering ions, and the binding capacity of Pb2+ and Cu2+ ions to the Fe7S8 nanomaterial. During the pH profile studies, the optimum pH for the binding of Pb2+ and Cu2+ was determined to be …


Preconditioning Methods For Thin Scattering Structures Based On Asymptotic Results, Josef A. Sifuentes, Shari Moskow Jul 2018

Preconditioning Methods For Thin Scattering Structures Based On Asymptotic Results, Josef A. Sifuentes, Shari Moskow

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We present a method to precondition the discretized Lippmann–Schwinger integral equations to model scattering of time-harmonic acoustic waves through a thin inhomogeneous scattering medium. The preconditioner is based on asymptotic results as the thickness of the third component direction goes to zero and requires solving a two dimensional formulation of the problem at the preconditioning step.


Design And Characterization Of An Affordable Laser Communication System, Andrea Tellez Jul 2018

Design And Characterization Of An Affordable Laser Communication System, Andrea Tellez

Theses and Dissertations

Over the last decades, an exponential growth in communication demand has been observed. Radio Frequency (RF) band has been one of the most used bandwidths for data transmission in the world. Given the influence and the continuous growth of communication technology, the RF spectrum is overpopulated. More efficient systems are necessary to meet the communication needs of this generation. A change to optical bandwidth is the most practical alternative to deal with the congestion of radio frequency.

The aim of this thesis is to present the features of Free Space Optical links with off-the-shelf components. A description of how these …


The Implementation Of A Fast-Folding Pipeline For Long-Period Pulsar Searching In The Palfa Survey, E. Parent, V. M. Kaspi, S. M. Ransom, M. Krasteva, C. Patel, P. Scholz, A. Brazier, M. A. Mclaughlin, M. Boyce, W. W. Zhu, Z. Pleunis, B. Allen, S. Bogdanov, K. Caballero, F. Camilo, R. Camuccio, S. Chatterjee, J. M. Cordes, F. Crawford, J. S. Deneva, R. Ferdman, P. C.C. Freire, J. W.T. Hessels, F. A. Jenet, B. Knispel, P. Lazarus, J. Van Leeuwen, A. G. Lyne, R. Lynch, A. Seymour Jul 2018

The Implementation Of A Fast-Folding Pipeline For Long-Period Pulsar Searching In The Palfa Survey, E. Parent, V. M. Kaspi, S. M. Ransom, M. Krasteva, C. Patel, P. Scholz, A. Brazier, M. A. Mclaughlin, M. Boyce, W. W. Zhu, Z. Pleunis, B. Allen, S. Bogdanov, K. Caballero, F. Camilo, R. Camuccio, S. Chatterjee, J. M. Cordes, F. Crawford, J. S. Deneva, R. Ferdman, P. C.C. Freire, J. W.T. Hessels, F. A. Jenet, B. Knispel, P. Lazarus, J. Van Leeuwen, A. G. Lyne, R. Lynch, A. Seymour

Physics and Astronomy Faculty Publications and Presentations

The Pulsar Arecibo L-Band Feed Array (PALFA) survey, the most sensitive blind search for radio pulsars yet conducted, is ongoing at the Arecibo Observatory in Puerto Rico. The vast majority of the 180 pulsars discovered by PALFA have spin periods shorter than 2 s. Pulsar surveys may miss long-period radio pulsars owing to the summing of a finite number of harmonic components in conventional Fourier analyses (typically ∼16), or as a result of the strong effect of red noise at low modulation frequencies. We address this reduction in sensitivity by using a time-domain search technique: the fast-folding algorithm (FFA). We …


Climate And Plant Controls On Soil Organic Matter In Coastal Wetlands, Michael J. Osland, Christopher A. Gabler, James B. Grace, Richard H. Day, Meagan L. Mccoy, Jennie L. Mcleod, Andrew S. From, Nicholas M. Enwright, Laura C. Feher, Camille L. Stagg Jun 2018

Climate And Plant Controls On Soil Organic Matter In Coastal Wetlands, Michael J. Osland, Christopher A. Gabler, James B. Grace, Richard H. Day, Meagan L. Mccoy, Jennie L. Mcleod, Andrew S. From, Nicholas M. Enwright, Laura C. Feher, Camille L. Stagg

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Coastal wetlands are among the most productive and carbon‐rich ecosystems on Earth. Long‐term carbon storage in coastal wetlands occurs primarily belowground as soil organic matter (SOM). In addition to serving as a carbon sink, SOM influences wetland ecosystem structure, function, and stability. To anticipate and mitigate the effects of climate change, there is a need to advance understanding of environmental controls on wetland SOM. Here, we investigated the influence of four soil formation factors: climate, biota, parent materials, and topography. Along the northern Gulf of Mexico, we collected wetland plant and soil data across elevation and zonation gradients within 10 …


Effect Of Surrounding Vegetation On Microbial Survival Or Die-Off On Watermelon Surface In An Agriculture Setting, Vijay Singh Chhetri, Kathryn Fontenot, Ronald Strahan, Veerachandra K. Yemmireddy, Katheryn J. Parraga Estrada, Achyut Adhikari Jun 2018

Effect Of Surrounding Vegetation On Microbial Survival Or Die-Off On Watermelon Surface In An Agriculture Setting, Vijay Singh Chhetri, Kathryn Fontenot, Ronald Strahan, Veerachandra K. Yemmireddy, Katheryn J. Parraga Estrada, Achyut Adhikari

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Preharvest contamination of produce with food borne pathogens has been a major food safety issue. In this study, we investigated the effect of surrounding vegetation on the survival of natural and inoculated generic Escherichia coli on watermelon rinds in an agricultural field setting. There was no significant difference (p > .05) on the populations of natural generic E. coli (1–1.46 log Most Probable Number (MPN)/sample) and coliforms (E. coli inoculated on watermelon rind discs was variable with the level of vegetation. A significant reduction in generic E. coli count was observed within 12 hr at all vegetation levels. After 108 …


Approximate Set Union Via Approximate Randomization, Bin Fu, Pengfei Gu, Yuming Zhao Jun 2018

Approximate Set Union Via Approximate Randomization, Bin Fu, Pengfei Gu, Yuming Zhao

Computer Science Faculty Publications and Presentations

No abstract provided.


First Record Of Black Corals (Antipatharia) In Shallow Coastal Waters Of Northern Chile By Means Of Underwater Video, Matthias Gorny, Erin E. Easton, Javier Sellanes Jun 2018

First Record Of Black Corals (Antipatharia) In Shallow Coastal Waters Of Northern Chile By Means Of Underwater Video, Matthias Gorny, Erin E. Easton, Javier Sellanes

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

This record is the first report of black corals (Antipatharia) in shallow waters of the continental coast of Chile, and extends their geographical range in shallow waters of the upper continental shelf of South America by ~3000 km from Ecuador (~1°S) to Coquimbo, Chile (~29°S). Specimens were observed between 70 and 107 m on three underwater video transects executed in July 2016 on the rocky reef El Toro, which is located about 65 km northwest of Coquimbo. The images were taken with the cameras of a remotely operated vehicle (ROV) at a distance of about two meters from the rocks. …


Microwave Popped Co(Ii)-Graphene Oxide Hybrid: Bifunctional Catalyst For Hydrogen Evolution Reaction And Hydrogen Storage, Lin Wei, Karen Lozano, Yuanbing Mao Jun 2018

Microwave Popped Co(Ii)-Graphene Oxide Hybrid: Bifunctional Catalyst For Hydrogen Evolution Reaction And Hydrogen Storage, Lin Wei, Karen Lozano, Yuanbing Mao

Chemistry Faculty Publications and Presentations

In an effort to develop a multifunctional catalyst for hydrogen generation and adsorption applications, a facile and cost-effective microwave popping method was used to synthesize popped graphene oxide (PGO) and Co-PGO hybrid. Both samples have been explored and compared as hydrogen storage materials and as electrocatalysts for hydrogen evolution reaction (HER) for the first time. The loading of Co(II) species on the surface of the PGO enhanced the hydrogen storage capability of PGO from 0.04wt% to 0.08wt% as measured at 293K and 800 mmHg. Co-PGO is also acting as a better electrocatalyst for HER compared to the PGO counterpart.


The Green Bank North Celestial Cap Pulsar Survey. Iii. 45 New Pulsar Timing Solutions, Ryan S. Lynch, Joseph K. Swiggum, Vlad I. Kondratiev, David L. Kaplan, Kevin Stovall, Emmanuel Fonseca, Mallory S.E. Roberts, Lina Levin, Megan E. Decesar, Bingyi Cui, S. Bradley Cenko, Pradip Gatkine, Anne M. Archibald, Shawn Banaszak, Christopher M. Biwer, Jason Boyles, Pragya Chawla, Louis P. Dartez, David Day, Anthony J. Ford, Joseph Flanigan, Jason W.T. Hessels, Jesus Hinojosa, Fredrick A. Jenet, Chen Karako-Argaman, Victoria M. Kaspi, Sean Leake, Grady Lunsford, José G. Martinez, Alberto Mata Jun 2018

The Green Bank North Celestial Cap Pulsar Survey. Iii. 45 New Pulsar Timing Solutions, Ryan S. Lynch, Joseph K. Swiggum, Vlad I. Kondratiev, David L. Kaplan, Kevin Stovall, Emmanuel Fonseca, Mallory S.E. Roberts, Lina Levin, Megan E. Decesar, Bingyi Cui, S. Bradley Cenko, Pradip Gatkine, Anne M. Archibald, Shawn Banaszak, Christopher M. Biwer, Jason Boyles, Pragya Chawla, Louis P. Dartez, David Day, Anthony J. Ford, Joseph Flanigan, Jason W.T. Hessels, Jesus Hinojosa, Fredrick A. Jenet, Chen Karako-Argaman, Victoria M. Kaspi, Sean Leake, Grady Lunsford, José G. Martinez, Alberto Mata

Physics and Astronomy Faculty Publications and Presentations

We provide timing solutions for 45 radio pulsars discovered by the Robert C. Byrd Green Bank Telescope. These pulsars were found in the Green Bank North Celestial Cap pulsar survey, an all-GBT-sky survey being carried out at a frequency of 350 MHz. We include pulsar timing data from the Green Bank Telescope and Low Frequency Array. Our sample includes five fully recycled millisecond pulsars (MSPs, three of which are in a binary system), a new relativistic double neutron star system, an intermediate-mass binary pulsar, a mode-changing pulsar, a 138 ms pulsar with a very low magnetic field, and several nulling …


Source-Specific Pollution Exposure And Associations With Pulmonary Response In The Atlanta Commuters Exposure Studies, Jenna R. Krall, Chandresh N. Ladva, Armistead G. Russell, Rachel Golan, Xing Peng, Guoliang Shi, Roby Greenwald, Amit U. Raysoni, Lance A. Waller, Jeremy A. Sarnat Jun 2018

Source-Specific Pollution Exposure And Associations With Pulmonary Response In The Atlanta Commuters Exposure Studies, Jenna R. Krall, Chandresh N. Ladva, Armistead G. Russell, Rachel Golan, Xing Peng, Guoliang Shi, Roby Greenwald, Amit U. Raysoni, Lance A. Waller, Jeremy A. Sarnat

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Concentrations of traffic-related air pollutants are frequently higher within commuting vehicles than in ambient air. Pollutants found within vehicles may include those generated by tailpipe exhaust, brake wear, and road dust sources, as well as pollutants from in-cabin sources. Sourcespecific pollution, compared to total pollution, may represent regulation targets that can better protect human health. We estimated source-specific pollution exposures and corresponding pulmonary response in a panel study of commuters. We used constrained positive matrix factorization to estimate source-specific pollution factors and, subsequently, mixed effects models to estimate associations between source-specific pollution and pulmonary response. We identified four pollution factors …


Charge Transfer Dynamical Processes At Graphene-Transition Metal Oxides/Electrolyte Interface For Energy Storage: Insights From In-Situ Raman Spectroelectrochemistry, S. Gupta, S. B. Carrizosa, J. Jasinski, N. Dimakis Jun 2018

Charge Transfer Dynamical Processes At Graphene-Transition Metal Oxides/Electrolyte Interface For Energy Storage: Insights From In-Situ Raman Spectroelectrochemistry, S. Gupta, S. B. Carrizosa, J. Jasinski, N. Dimakis

Physics and Astronomy Faculty Publications and Presentations

Hybrids consisting of supercapacitive functionalized graphene (graphene oxide; GO reduced graphene oxide; rGO multilayer graphene; MLG, electrochemically reduced GO; ErGO) and three-dimensional graphene scaffold (rGO HT ; hydrothermally prepared) decorated with cobalt nanoparticles (CoNP), nanostructured cobalt (CoO and Co 3 O 4 ) and manganese (MnO 2 ) oxide polymorphs, assembled electrochemically facilitate chemically bridged interfaces with tunable properties. Since Raman spectroscopy can capture variations in structural and chemical bonding, Raman spectro-electrochemistry in operando i.e. under electrochemical environment with applied bias is employed to 1) probe graphene/metal bonding and dynamic processes, 2) monitor the spectral changes with successive redox interfacial …


The Nanograv 11 Year Data Set: Pulsar-Timing Constraints On The Stochastic Gravitational-Wave Background, Zaven Arzoumanian, P. T. Baker, A. Brazier, S. Burke-Spolaor, S. J. Chamberlin, S. Chatterjee, B. Christy, ‪Jeffrey S. Hazboun, Jing Luo May 2018

The Nanograv 11 Year Data Set: Pulsar-Timing Constraints On The Stochastic Gravitational-Wave Background, Zaven Arzoumanian, P. T. Baker, A. Brazier, S. Burke-Spolaor, S. J. Chamberlin, S. Chatterjee, B. Christy, ‪Jeffrey S. Hazboun, Jing Luo

Physics and Astronomy Faculty Publications and Presentations

We search for an isotropic stochastic gravitational-wave background (GWB) in the newly released 11 year data set from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). While we find no evidence for a GWB, we place constraints on a population of inspiraling supermassive black hole (SMBH) binaries, a network of decaying cosmic strings, and a primordial GWB. For the first time, we find that the GWB constraints are sensitive to the solar system ephemeris (SSE) model used and that SSE errors can mimic a GWB signal. We developed an approach that bridges systematic SSE differences, producing the first pulsar-timing …


A Comparison Of Salinity Effects From Hurricanes Dolly (2008) And Alex (2010) In A Texas Lagoon System, Joseph L. Kowalski, Hudson R. Deyoe, Gilbert H. Boza Jr., Donald L. Hockaday, Paul V. Zimba May 2018

A Comparison Of Salinity Effects From Hurricanes Dolly (2008) And Alex (2010) In A Texas Lagoon System, Joseph L. Kowalski, Hudson R. Deyoe, Gilbert H. Boza Jr., Donald L. Hockaday, Paul V. Zimba

Biology Faculty Publications and Presentations

A comparison of salinity effects from hurricanes Dolly (2008) and Alex (2010) in a Texas lagoon system.Hurricanes are not uncommon along the Gulf of Mexico coast, but there are few studies of the effects they have on coastal embayments. Hurricanes Dolly (2008) and Alex (2010) were both Category 2 storms affecting the Lower Laguna Madre (LLM) of Texas. Surveys were performed to assess poststorm water quality after landfall of both storms at up to 18 sample stations. The main difference between storm effects was salinity reduction because of stormwater input from the watershed. Effects from Hurricane Dolly were of short …


Search For Tensor Vector And Scalar Polarizations In The Stochastic Gravitational-Wave Background, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier May 2018

Search For Tensor Vector And Scalar Polarizations In The Stochastic Gravitational-Wave Background, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier

Physics and Astronomy Faculty Publications and Presentations

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find …