Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Faculty Publications

Discipline
Institution
Keyword
Publication Year
File Type

Articles 2791 - 2820 of 9025

Full-Text Articles in Entire DC Network

Towards A Splitter Theorem For Internally 4-Connected Binary Matroids Vii, Carolyn Chun, James Oxley Mar 2019

Towards A Splitter Theorem For Internally 4-Connected Binary Matroids Vii, Carolyn Chun, James Oxley

Faculty Publications

Let M be a 3-connected binary matroid; M is internally 4-connected if one side of every 3-separation is a triangle or a triad, and M is (4,4,S)-connected if one side of every 3-separation is a triangle, a triad, or a 4-element fan. Assume M is internally 4-connected and that neither M nor its dual is a cubic Möbius or planar ladder or a certain coextension thereof. Let N be an internally 4-connected proper minor of M. Our aim is to show that M has a proper internally 4-connected minor with an N-minor that can be obtained from M either by …

Go to article

Robust Resource Allocation With Imperfect Channel Estimation In Noma-Based Heterogeneous Vehicular Networks, Shengjie Guo, Xiangwei Zhou Mar 2019

Robust Resource Allocation With Imperfect Channel Estimation In Noma-Based Heterogeneous Vehicular Networks, Shengjie Guo, Xiangwei Zhou

Faculty Publications

In heterogeneous vehicular networks, non-orthogonal multiple access (NOMA) with effective resource allocation improves spectrum efficiency by allowing multiple users to share the same channel. However, channel estimation errors caused by high mobility in vehicular networks affect system robustness and link reliability. As a result, resource allocation in high-mobility scenarios is a challenging issue. In this paper, robust resource allocation is studied to improve both the throughput performance and reliability of NOMA-based heterogeneous vehicular networks. A cascaded Hungarian channel assignment algorithm is proposed to simplify the formulated resource allocation problem with reliability requirements into a robust power allocation problem with chance …

Go to article

36% Reduction In Fuel Resupply Using A Hybrid Generator & Battery System For An Austere Location, David J. Chester, Torrey J. Wagner, Douglas S. Dudis Mar 2019

36% Reduction In Fuel Resupply Using A Hybrid Generator & Battery System For An Austere Location, David J. Chester, Torrey J. Wagner, Douglas S. Dudis

Faculty Publications

The DOD energy policy is to increase energy security resiliency, and mitigate costs in the use and management of energy[1] Forward operating bases (FOBs) are remote, austere base camps that support an operationally defined mission with a limited or no ability to draw from an energy grid and have historically relied on diesel-powered generators for the primary production of energy.[2] Generators are sized to meet a theoretical peak demand, but steady state loads are far below this peak, resulting in under-loaded generators.[3] Under-loaded diesel generators decrease efficiency and increase the need for maintenance, affecting the lifespan of …

Go to article

Erratum: “The Sluggs Survey: A Catalog Of Globular Cluster Radial Velocities” (2017, Aj, 153, 114), Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky, Jay Strader, Caroline Foster, Christopher Usher, Lee Spitler, Sabine Bellstedt, Nicola Pastorello, Sreeja Kartha, Zach Jennings, Alexa Villaume, Asher Wasserman, Vincenzo Pota Mar 2019

Erratum: “The Sluggs Survey: A Catalog Of Globular Cluster Radial Velocities” (2017, Aj, 153, 114), Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky, Jay Strader, Caroline Foster, Christopher Usher, Lee Spitler, Sabine Bellstedt, Nicola Pastorello, Sreeja Kartha, Zach Jennings, Alexa Villaume, Asher Wasserman, Vincenzo Pota

Faculty Publications

We would like to point out to the reader that the catalog of globular cluster (GC) radial velocities (listed in Table 5) still contains some multiple entries. In such cases GCs were observed more than once and are recorded in Table 5 with a unique GC ID, along with their coordinates and radial velocity measurement. If the reader wishes to exclude, or average, multiple measurements then GCs within one spatial pixel (i.e., 0.119 arcsec) in R.A. and decl. can be identified. This would include two dozen GCs in the galaxies NGC 720, 1407, 2768, 3608, 4365, 4459, 4474, and 4697. …

Go to article

Shaping The Far-Zone Intensity, Degree Of Polarization, Angle Of Polarization, And Ellipticity Angle Using Vector Schell-Model Sources, Milo W. Hyde Iv Mar 2019

Shaping The Far-Zone Intensity, Degree Of Polarization, Angle Of Polarization, And Ellipticity Angle Using Vector Schell-Model Sources, Milo W. Hyde Iv

Faculty Publications

This paper presents a method to control both the shape and polarization of a beam in the far field using a vector Schell-model source. Given a desired far-zone beam shape and polarization, and applying Fourier and statistical optics theory, we derive the requisite second-order moments of said source, discuss what aspects of the far-zone beam can be controlled, and develop a step-by-step procedure for synthesizing the required random vector field instances. We validate this approach with Monte-Carlo wave-optics simulations. The results are found to be in very good agreement with the desired far-zone beam characteristics. The beam-shaping technique developed in …

Go to article

Two-Pebbling And Odd-Two-Pebbling Are Not Equivalent, Charles A. Cusack, Airat Bekmetjev, Mark Powers Mar 2019

Two-Pebbling And Odd-Two-Pebbling Are Not Equivalent, Charles A. Cusack, Airat Bekmetjev, Mark Powers

Faculty Publications

Let G be a connected graph. A configuration of pebbles assigns a nonnegative integer number of pebbles to each vertex of G. A move consists of removing two pebbles from one vertex and placing one pebble on an adjacent vertex. A configuration is solvable if any vertex can get at least one pebble through a sequence of moves. The pebbling number of G, denoted π(G), is the smallest integer such that any configuration of π(G) pebbles on G is solvable. A graph has the two-pebbling property if after placing more than 2π(G) -- q pebbles on G …

Go to article

Observation Of The Decay D0 → K− Π + E + E −, J.P. Lees, P. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu. G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, V. B. Golubev, Milind Purohit, Et. Al. Feb 2019

Observation Of The Decay D0 → K− Π + E + E −, J.P. Lees, P. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu. G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, V. B. Golubev, Milind Purohit, Et. Al.

Faculty Publications

We report the observation of the rare charm decay D0 → K−πþeþe−, based on 468 fb−1 of eþe− annihilation data collected at or close to the center-of-mass energy of the ϒð4SÞ resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range 0.675 < m(e+e−) < 0.875 GeV=c2 of the electron-positron pair to be B(D0 → K−π+e+e−) = (4.0 ± 0.5 ± 0.2 ± 0.1) × 10−6, where the first uncertainty is statistical, the second …

Go to article

Bio-Inspired Sensing And Actuating Architectures For Feedback Control Of Civil Structures, Courtney A. Peckens, I. Cook, C. Fogg Feb 2019

Bio-Inspired Sensing And Actuating Architectures For Feedback Control Of Civil Structures, Courtney A. Peckens, I. Cook, C. Fogg

Faculty Publications

Civil structures, such as buildings and bridges, are constantly at risk of failure due to external environmental loads, such as earthquakes or strong winds. To minimize the effects of these loads, active feedback control systems have been proposed but such systems still face numerous challenges which impede their widespread adoption. In order to overcome many of these challenges, inspiration can be drawn from the signal processing and actuating techniques employed by the biological central nervous system to develop a bio-inspired control algorithm. In this study the front-end, signal processing techniques employed by biological sensory systems, and in particular the mammalian …

Go to article

Application Of The Second-Order Comprehensive Adjoint Sensitivity Analysis Methodology To Compute First- And Second-Order Sensitivities Of Flux Functionals In A Multiplying System With Source, Dan Gabriel Cacuci Feb 2019

Application Of The Second-Order Comprehensive Adjoint Sensitivity Analysis Methodology To Compute First- And Second-Order Sensitivities Of Flux Functionals In A Multiplying System With Source, Dan Gabriel Cacuci

Faculty Publications

This work presents an application of the Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) to the neutron transport Boltzmann equation that models a multiplying subcritical system comprising a nonfission neutron source to compute efficiently and exactly all of the first- and second-order functional derivatives (sensitivities) of a detector’s response to all of the model’s parameters, including isotopic number densities, microscopic cross sections, fission spectrum, sources, and detector response function. As indicated by the general theoretical considerations underlying the 2nd-ASAM, the number of computations required to obtain the first and second orders increases linearly in augmented Hilbert spaces as opposed to increasing …

Go to article

Search For A Stable Six-Quark State At Babar, J. P. Lees, V. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, V. B. Golubev, Milind Purohit Feb 2019

Search For A Stable Six-Quark State At Babar, J. P. Lees, V. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, V. B. Golubev, Milind Purohit

Faculty Publications

Recent investigations have suggested that the six-quark combination uuddss could be a deeply bound state (S) that has eluded detection so far, and a potential dark matter candidate. We report the first search for a stable, doubly strange six-quark state in ϒ → SΛ¯ Λ¯ decays based on a sample of 90 × 106ϒ(2S) and 110 × 106ϒ(3S) decays collected by the BABAR experiment. No signal is observed, and 90% confidence level limits on the combined ϒ(2S; 3S) → SΛ¯ Λ¯ branching fraction in the range (1.2–1.4) × 10−7 are derived for m …

Go to article

Soil Macroinvertebrate Presence Alters Microbial Community Composition And Activity In The Rhizosphere, Natalie Bray, Jenny Kao-Kniffin, Serita D. Frey, Timothy Fahey, Kyle Wickings Feb 2019

Soil Macroinvertebrate Presence Alters Microbial Community Composition And Activity In The Rhizosphere, Natalie Bray, Jenny Kao-Kniffin, Serita D. Frey, Timothy Fahey, Kyle Wickings

Faculty Publications

Soil Macroinvertebrate Presence Alters Microbial Community Composition and Activity in the Rhizosphere

Go to article

Large Fatty Acid-Derived Aβ42 Oligomers Form Ring-Like Assemblies, Wenhui Xu, Dexter N. Dean, Kelli A. Stockmal, Sarah E. Morgan, Ulrich H.E. Hansmann, Vijayaraghavan Rangachari Feb 2019

Large Fatty Acid-Derived Aβ42 Oligomers Form Ring-Like Assemblies, Wenhui Xu, Dexter N. Dean, Kelli A. Stockmal, Sarah E. Morgan, Ulrich H.E. Hansmann, Vijayaraghavan Rangachari

Faculty Publications

As the primary toxic species in the etiology of Alzheimer disease (AD) are low molecular weight oligomers of Aβ, it is crucial to understand the structure of Aβ oligomers for gaining molecular insights into AD pathology. We have earlier demonstrated that in the presence of fatty acids, Aβ42 peptides assemble as 12-24mer oligomers. These Large Fatty Acid-derived Oligomers (LFAOs) exist predominantly as 12mers at low and as 24mers at high concentrations. The 12mers are more neurotoxic than the 24mers and undergo self-replication, while the latter propagate to morphologically distinct fibrils with succinct pathological consequences. In order to glean into their …

Go to article

Realization Of A Type-Ii Nodal-Line Semimetal In Mg3bi2, Weiwei Xie Feb 2019

Realization Of A Type-Ii Nodal-Line Semimetal In Mg3bi2, Weiwei Xie

Faculty Publications

Nodal-line semimetals (NLSs) represent a new type of topological semimetallic phase beyond Weyl and Dirac semimetals in the sense that they host closed loops or open curves of band degeneracies in the Brillouin zone. Parallel to the classification of type-I and type-II Weyl semimetals, there are two types of NLSs. The type-I NLS phase has been proposed and realized in many compounds, whereas the exotic type-II NLS phase that strongly violates Lorentz symmetry has remained elusive. First-principles calculations show that Mg3Bi2 is a material candidate for the type-II NLS. The band crossing is close to the Fermi level and exhibits …

Go to article

Toxoplasma Gondii Igg Associations With Sleepwake Problems, Sleep Duration And Timing, Celine C. Corona, Ma Zhang, Abhishek Wadhawan, Melanie L. Daue, Maureen W. Groer, Aline Dagang, Christopher A. Lowry, Kathleen A. Ryan, Andrew J. Hoisington, John W. Stiller, Dietmar Fuchs, Braxton D. Mitchell, Teodor T. Postolache Feb 2019

Toxoplasma Gondii Igg Associations With Sleepwake Problems, Sleep Duration And Timing, Celine C. Corona, Ma Zhang, Abhishek Wadhawan, Melanie L. Daue, Maureen W. Groer, Aline Dagang, Christopher A. Lowry, Kathleen A. Ryan, Andrew J. Hoisington, John W. Stiller, Dietmar Fuchs, Braxton D. Mitchell, Teodor T. Postolache

Faculty Publications

Background: Evidence links Toxoplasma gondii (T. gondii), a neurotropic parasite, with schizophrenia, mood disorders and suicidal behavior, all of which are associated and exacerbated by disrupted sleep. Moreover, low-grade immune activation and dopaminergic overstimulation, which are consequences of T. gondii infection, could alter sleep patterns and duration. Methods: Sleep data on 833 Amish participants [mean age (SD) = 44.28 (16.99) years; 59.06% women] were obtained via self-reported questionnaires that assessed sleep problems, duration and timing. T. gondii IgG was measured with ELISA. Data were analyzed using multivariable logistic regressions and linear mixed models, with adjustment for age, sex and family …

Go to article

Near Earth Space Object Detection Using Parallax As Multi-Hypothesis Test Criterion, Joseph C. Tompkins, Stephen C. Cain, David J. Becker Feb 2019

Near Earth Space Object Detection Using Parallax As Multi-Hypothesis Test Criterion, Joseph C. Tompkins, Stephen C. Cain, David J. Becker

Faculty Publications

The US Strategic Command (USSTRATCOM) operated Space Surveillance Network (SSN) is tasked with Space Situational Awareness (SSA) for the U.S. military. This system is made up of Electro-Optic sensors, such as the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) and RADAR based sensors, such as the Space Fence Gaps. They remain in the tracking of Resident Space Objects (RSO’s) in Geosynchronous Orbits (GEO), due to limitations of SST and GEODSS system implementation. This research explores a reliable, ground-based technique used to quickly determine an RSO’s altitude from a single or limited set of observations. Implementation of such sensors into the SSN …

Go to article

Experimental Study: Underwater Propagation Of Super-Gaussian And Multi-Gaussian Schell-Model Partially Coherent Beams With Varying Degrees Of Spatial Coherence, Svetlana Avramov-Zamurovic, Charles L. Nelson, Milo W. Hyde Iv Feb 2019

Experimental Study: Underwater Propagation Of Super-Gaussian And Multi-Gaussian Schell-Model Partially Coherent Beams With Varying Degrees Of Spatial Coherence, Svetlana Avramov-Zamurovic, Charles L. Nelson, Milo W. Hyde Iv

Faculty Publications

We report on experiments where super-Gaussian and flat-top, multi-Gaussian Schell-model spatially partially coherent beams, with varying degrees of spatial coherence, were propagated underwater. Two scenarios were explored—calm and mechanically agitated water. The main objective of our study was the experimental comparison of the scintillation statistics. For a similar degree of coherence widths, the results show a potentially improved performance of scintillation index for the multi-Gaussian Schell-model beams as compared to the super-Gaussian beams. It should be noted that the presented results pertain only to the given experimental scenarios and further investigation is necessary to determine the scope of the findings.

Go to article

Deep Sea Biofilms, Historic Shipwreck Preservation And The Deepwater Horizon Spill, Rachel L. Mugge, Melissa L. Brock, Jennifer L. Salerno, Melanie Damour, Robert A. Church, Jason Lee, Leila J. Hamdan Feb 2019

Deep Sea Biofilms, Historic Shipwreck Preservation And The Deepwater Horizon Spill, Rachel L. Mugge, Melissa L. Brock, Jennifer L. Salerno, Melanie Damour, Robert A. Church, Jason Lee, Leila J. Hamdan

Faculty Publications

Exposure to oil from the Deepwater Horizon spill may have lasting impacts on preservation of historic shipwrecks in the Gulf of Mexico. Submerged steel structures, including shipwrecks, serve as artificial reefs and become hotspots of biodiversity in the deep-sea. Marine biofilms on submerged structures support settlement of micro- and macrobiota and may enhance and protect against corrosion. Disruptions in the local environment, including oil spills, may impact the role that biofilms play in reef preservation. To determine how the Deepwater Horizon spill potentially impacted shipwreck biofilms and the functional roles of the biofilm microbiome, experiments containing carbon steels disks (CSDs) …

Go to article

Vertical Marine Snow Distribution In The Stratified Hypersaline, And Anoxic Orca Basin (Gulf Of Mexico), Arne Diercks, Kai Ziervogel, Ryan Sibert, Samantha B. Joye, Vernon Asper Feb 2019

Vertical Marine Snow Distribution In The Stratified Hypersaline, And Anoxic Orca Basin (Gulf Of Mexico), Arne Diercks, Kai Ziervogel, Ryan Sibert, Samantha B. Joye, Vernon Asper

Faculty Publications

We present a complete description of the depth distribution of marine snow in Orca Basin (Gulf of Mexico), from sea surface through the pycnocline to within 10 m of the seafloor. Orca Basin is an intriguing location for studying marine snow because of its unique geological and hydrographic setting: the deepest ~200 m of the basin are filled with anoxic hypersaline brine. A typical deep ocean profile of marine snow distribution was observed from the sea surface to the pycnocline, namely a surface maximum in total particle number and midwater minimum. However, instead of a nepheloid (particle-rich) layer positioned near …

Go to article

Substrate-Dependent Photoconductivity Dynamics In A High-Efficiency Hybrid Perovskite Alloy, Ali Moeed Tirmzi, Jeffrey A. Christians, Ryan P. Dwyer, David T. Moore, John A. Marohn Feb 2019

Substrate-Dependent Photoconductivity Dynamics In A High-Efficiency Hybrid Perovskite Alloy, Ali Moeed Tirmzi, Jeffrey A. Christians, Ryan P. Dwyer, David T. Moore, John A. Marohn

Faculty Publications

Films of (FA0.79MA0.16Cs0.05)0.97Pb(I0.84Br0.16)2.97 were grown over TiO2, SnO2, indium tin oxide (ITO), and NiO. Film conductivity was interrogated by measuring the in-phase and out-of-phase forces acting between the film and a charged microcantilever. We followed the films’ conductivity versus time, frequency, light intensity, and temperature (233−312 K). Perovskite conductivity was high and light-independent over ITO and NiO. Over TiO2 and SnO2, the conductivity was low in the dark,increased with light intensity, and persisted for 10’s of seconds after the light …

Go to article

Constraining The P-Mode-G-Mode Tidal Instability With Gw170817, 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, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya Feb 2019

Constraining The P-Mode-G-Mode Tidal Instability With Gw170817, 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, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya

Faculty Publications

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: An overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB!pgpg) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform …

Go to article

Developable Mechanisms On Developable Surfaces, Todd G. Nelson, Trent K. Zimmerman, Robert J. Lang, Spencer P. Magleby, Larry L. Howell Feb 2019

Developable Mechanisms On Developable Surfaces, Todd G. Nelson, Trent K. Zimmerman, Robert J. Lang, Spencer P. Magleby, Larry L. Howell

Faculty Publications

The trend toward smaller mechanism footprints and volumes, while maintaining the ability to perform complex tasks, presents the opportunity for exploration of hypercompact mechanical systems integrated with curved surfaces. Developable surfaces are shapes that a flat sheet can take without tearing or stretching, and they represent a wide range of manufactured surfaces. This work introduces “developable mechanisms” as devices that emerge from or conform to developable surfaces. They are made possible by aligning hinge axes with developable surface ruling lines to enable mobility. Because rigid-link motion depends on the relative orientation of hinge axes and not link geometry, links can …

Go to article

Multifractality Of Posture Modulates Multisensory Perception Of Stand-On-Ability, Jonathan K. Doyon, Alen Hajnal, Tyler Surber, Joseph D. Clark, Damian G. Kelty-Stephen Feb 2019

Multifractality Of Posture Modulates Multisensory Perception Of Stand-On-Ability, Jonathan K. Doyon, Alen Hajnal, Tyler Surber, Joseph D. Clark, Damian G. Kelty-Stephen

Faculty Publications

By definition, perception is a multisensory process that unfolds in time as a complex sequence of exploratory activities of the organism. In such a system perception and action are integrated, and multiple energy arrays are available simultaneously. Perception of affordances interweaves sensory and motor activities into meaningful behavior given task constraints. The present contribution offers insight into the manner in which perception and action usher the organism through competent functional apprehension of its surroundings. We propose that the tensegrity structure of the body, manifested via multifractality of exploratory bodily movements informs perception of affordances. The affordance of stand-on-ability of ground …

Go to article

A New Multivariate Optical Computing Microelement And Miniature Sensor For Spectroscopic Chemical Sensing In Harsh Environments: Design, Fabrication, And Testing, Christopher M. Jones, Bin Dai, Jimmy Price, Jian Li, Megan Pearl, Bill Soltmann, Michael L. Myrick Feb 2019

A New Multivariate Optical Computing Microelement And Miniature Sensor For Spectroscopic Chemical Sensing In Harsh Environments: Design, Fabrication, And Testing, Christopher M. Jones, Bin Dai, Jimmy Price, Jian Li, Megan Pearl, Bill Soltmann, Michael L. Myrick

Faculty Publications

Multivariate optical computing (MOC) is a compressed sensing technique with the ability to provide accurate spectroscopic compositional analysis in a variety of different applications to multiple industries. Indeed, recent developments have demonstrated the successful deployment of MOC sensors in downhole/well-logging environments to interrogate the composition of hydrocarbon and other chemical constituents in oil and gas reservoirs. However, new challenges have necessitated sensors that operate at high temperatures and pressures (up to 230 °C and 138 MPa) as well as even smaller areas that require the miniaturization of their physical footprint. To this end, this paper details the design, fabrication, and …

Go to article

Exposure Characterization Of Haloacetic Acids In Humans For Exposure And Risk Assessment Applications: An Exploratory Study, Shahid Parvez, Jeffrey L. Ashby, Susana Y. Kimura, Susan D. Richardson Feb 2019

Exposure Characterization Of Haloacetic Acids In Humans For Exposure And Risk Assessment Applications: An Exploratory Study, Shahid Parvez, Jeffrey L. Ashby, Susana Y. Kimura, Susan D. Richardson

Faculty Publications

Disinfected water is the major source of haloacetic acids (HAAs) in humans, but their inter- and intra-individual variability for exposure and risk assessment applications is under-researched. Thus, we measured HAAs in cross-sectional and longitudinal urine and water specimens from 17 individuals. Five regulated HAAs—mono-, di-, and trichloroacetic acid (MCAA, DCAA, and TCAA) and mono- and dibromoacetic acid (MBAA and DBAA)—and one unregulated HAA—bromochloroacetic acid (BCAA)—were measured. Urinary DCAA, MBAA, DBAA, and BCAA levels were always below the limits of detection (LOD). Measured levels and interindividual variability of urinary MCAA were higher than urinary TCAA. Longitudinal urinary specimens showed MCAA levels …

Go to article

Retrieval Of Phytoplankton Pigments From Underway Spectrophotometry In The Fram Strait, Yangyang Liu, Emmanuel Boss, Alison Chase, Hongyan Xi, Xiaodong Zhang, Rüdiger Röttgers, Yanqun Pan, Astrid Bracher Feb 2019

Retrieval Of Phytoplankton Pigments From Underway Spectrophotometry In The Fram Strait, Yangyang Liu, Emmanuel Boss, Alison Chase, Hongyan Xi, Xiaodong Zhang, Rüdiger Röttgers, Yanqun Pan, Astrid Bracher

Faculty Publications

Phytoplankton in the ocean are extremely diverse. The abundance of various intracellular pigments are often used to study phytoplankton physiology and ecology, and identify and quantify different phytoplankton groups. In this study, phytoplankton absorption spectra (αph(λ)) derived from underway flow-through AC-S measurements in the Fram Strait are combined with phytoplankton pigment measurements analyzed by high-performance liquid chromatography (HPLC) to evaluate the retrieval of various pigment concentrations at high spatial resolution. The performances of two approaches, Gaussian decomposition and the matrix inversion technique are investigated and compared. Our study is the first to apply the matrix inversion …

Go to article

Model Predictive Automatic Control Of Sucker Rod Pump System With Simulation Case Study, Brigham Hansen, Brandon Tolbert, Cory Vernon, John Hedengren Feb 2019

Model Predictive Automatic Control Of Sucker Rod Pump System With Simulation Case Study, Brigham Hansen, Brandon Tolbert, Cory Vernon, John Hedengren

Faculty Publications

This work enables accelerated fluid recovery in oil and gas reservoirs by automatically controlling fluid height and bottomhole pressure in wells. Several literature studies show significant increase in recovered oil by determining a target bottomhole pressure but rarely consider how to control to that value. This work enables those benefits by maintaining bottomhole pressure or fluid height. Moving Horizon Estimation (MHE) determines uncertain well parameters using only common surface measurements. A Model Predictive Controller (MPC) adjusts the stroking speed of a sucker rod pump to maintain fluid height. Pump boundary conditions are simulated with Mathematical Programs with Complementarity Constraints (MPCCs) …

Go to article

In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann Feb 2019

In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann

Faculty Publications

The dolomitization and diagenetic history of Ordovician carbonates of southern Wisconsin is complex. Previous studies attributed dolomitization to various diagenetic factors and environments. In this study, high-resolution, in situ laser ablation inductively coupled mass spectrometry analysis of rare earth element patterns of dolomite was used to assess the diagenetic fluids responsible for dolomitization of the Ordovician Decorah Formation. Integrated geochemical data and petrographic evidence suggest that the dolostones are formed in two different diagenetic realms: shallow burial and hydrothermal. Shallow burial dolomites exhibit three distinct rare earth element patterns. Dolomite from the middle portion of the Guttenberg Member exhibits light …

Go to article

Surface Coupling Of Octaethylporphyrin With Silicon Tetrachloride, Jayne C. Garno, Phillip C. Chambers, Neepa M. K. Kuruppu Arachchige, Ashley M. Taylor Feb 2019

Surface Coupling Of Octaethylporphyrin With Silicon Tetrachloride, Jayne C. Garno, Phillip C. Chambers, Neepa M. K. Kuruppu Arachchige, Ashley M. Taylor

Faculty Publications

The surface assembly of 2,3,7,8,12,13,17,18-octaethylporphyrin (OEP) using silicon tetrachloride as a coupling agent was investigated using atomic force microscopy (AFM). Nanopatterned films of Si-OEP were prepared by protocols of colloidal lithography to evaluate the morphology, thickness, and molecular orientation for samples prepared on Si(111). The natural self-stacking of porphyrins can pose a challenge for molecular patterning. When making films on surfaces, porphyrins will self-associate to form co-planar configurations of random stacks of molecules. There is a tendency for the flat molecules to orient spontaneously in a side-on arrangement that is mediated by physisorption to the substrate as well as by …

Go to article

Factors Affecting Growth Kinetics And Spontaneous Metastasis In The B16f10 Syngeneic Murine Melanoma Model, Natalie Fowlkes, Kelli Clemons, Paul Jf Rider, Ramesh Subramanian, Nobuko Wakamatsu, Ingeborg Langohr, Konstantin G. Kousoulas Feb 2019

Factors Affecting Growth Kinetics And Spontaneous Metastasis In The B16f10 Syngeneic Murine Melanoma Model, Natalie Fowlkes, Kelli Clemons, Paul Jf Rider, Ramesh Subramanian, Nobuko Wakamatsu, Ingeborg Langohr, Konstantin G. Kousoulas

Faculty Publications

Melanoma is an immunogenic tumor that can metastasize quickly to proximal and distal sites, thus complicating the application of therapeutic modalities. Numerous mouse model systems have been used to gain understanding of the immunobiology and metastatic potential of melanoma. Here, we report the optimization of a syngeneic mouse melanoma model protocol using the mouse B16-derived melanoma cell line B16F10 that ensures the production of tumors on mice pinnae that are similar in size between animals and that enlarge in a time-dependent manner. In this model, B16F10 cells are first allowed to develop tumors after injection in the interscapular area or …

Go to article

Functional Polymers Through Mechanochemistry, Stephen Schrettl, Diedrik W.R. Balkenende, Céline Calvino, Marc Karman, Ana Lavrenova, Laura N. Neumann, Yoshimitsu Sagara, Ester Verde-Sesto, Michela Di Giannantonio, Yoan C. Simon, Katharina M. Fromm, Marco Lattuada, Christoph Weder Feb 2019

Functional Polymers Through Mechanochemistry, Stephen Schrettl, Diedrik W.R. Balkenende, Céline Calvino, Marc Karman, Ana Lavrenova, Laura N. Neumann, Yoshimitsu Sagara, Ester Verde-Sesto, Michela Di Giannantonio, Yoan C. Simon, Katharina M. Fromm, Marco Lattuada, Christoph Weder

Faculty Publications

While coupling mechanical and chemical processes is widespread in living organisms, the idea to harness the mechanically induced dissociation of weak covalent and non-covalent bonds to create artificial materials that respond to mechanical stimulation has only recently gained attention. Here we summarize our activities that mainly revolve around the exploitation of non-covalent interactions in (supramolecular) polymeric materials with the goal to translate mechanical stresses into useful, pre-defined events. Focusing on mechano- chromic polymers that alter their optical absorption or fluorescence properties, several new operating principles, mechanosensitive entities, and materials systems were developed. Such materials are expected to be useful for …

Go to article

First Prev Next Last