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2018

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Articles 1861 - 1890 of 13646

Full-Text Articles in Physical Sciences and Mathematics

The Subject Librarian Newsletter, Engineering And Computer Science, Spring 2016, Ven Basco Oct 2018

The Subject Librarian Newsletter, Engineering And Computer Science, Spring 2016, Ven Basco

Buenaventura "Ven" Basco

No abstract provided.


The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2016, Buenaventura "Ven" Basco Oct 2018

The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2016, Buenaventura "Ven" Basco

Buenaventura "Ven" Basco

No abstract provided.


The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2015, Ven Basco Oct 2018

The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2015, Ven Basco

Buenaventura "Ven" Basco

No abstract provided.


Selected Adventures In Policy Modeling, Edward Kaplan Oct 2018

Selected Adventures In Policy Modeling, Edward Kaplan

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.


Reducing The Maximum Degree Of A Graph By Deleting Vertices: The Extremal Cases, Peter Borg, Kurt Fenech Oct 2018

Reducing The Maximum Degree Of A Graph By Deleting Vertices: The Extremal Cases, Peter Borg, Kurt Fenech

Theory and Applications of Graphs

Let λ(G) denote the smallest number of vertices that can be removed from a non-empty graph G so that the resulting graph has a smaller maximum degree. In a recent paper, we proved that if n is the number of vertices of G,k is the maximum degree of G, and t is the number of vertices of degree k, then λ: (G) ≤ n+(k-1)t}{2k}. We also showed that λ (G) ≤ \frac{n}{k+1} if G is a tree. In this paper, we provide a new proof of the first bound and use it to determine the graphs that …


Expected And Achievable Accuracy In Estimating Parameters Of Standing Accretion Shock Instability (Sasi) Fluctuations From Neutrinos And Gravitational Wave Oscillations, Colter Richardson, Jonathan Westhouse Oct 2018

Expected And Achievable Accuracy In Estimating Parameters Of Standing Accretion Shock Instability (Sasi) Fluctuations From Neutrinos And Gravitational Wave Oscillations, Colter Richardson, Jonathan Westhouse

Undergraduate Research Symposium - Prescott

Core collapse supernovae are one of the most interesting sources of gravitational waves. When the progenitor star is particularly massive, hydrodynamic instability called standing accretion shock instability can develop and it is characterized by deterministic oscillations in the gravitational wave signal as well as in the neutrino luminosity with frequencies of 100hz. In this talk we will review current efforts to extract physical information from the SASI components of the gravitational wave and enhance the detectability of gravitational waves with such components both using laser interferometers and neutrino detectors.


Modeling And Detectability Of Gravitational Wave Waveform Memory From Core Collapse Supernovae, Pedro Jesus Quinonez, Emily Grimes Oct 2018

Modeling And Detectability Of Gravitational Wave Waveform Memory From Core Collapse Supernovae, Pedro Jesus Quinonez, Emily Grimes

Undergraduate Research Symposium - Prescott

Ever since the discovery of gravitational waves by LIGO, studying these waves have become of utmost importance. This is because gravitational waves have the potential to carry information that have remain unseen by physicist in the past. For example, take the case of a core collapse supernovae. Any information transferred through electromagnetic waves that attempts to escape the inner core of a dying star is blocked out by the intense radiation of its outer shell. For this reason, astronomers have been unable to truly study what goes in the core. However, this is not the case for gravitational waves, which …


Research In Optics For Gravitational Wave Detection, Britney Biltz, Noura Ibrahim, Brennan Moore Oct 2018

Research In Optics For Gravitational Wave Detection, Britney Biltz, Noura Ibrahim, Brennan Moore

Undergraduate Research Symposium - Prescott

B.Biltz uses a horizontal “Zollner style” pendulum to monitor changes in the local gravitational field. The pendulum is attracted to the moon and the Sun and so, as the Earth turns, the pendulum’s equilibrium point shifts within a 24-hour period. This is an experiment designed to test the limits of such a pendulum. This sort of system may be useful as a method of monitoring and correcting for gravity gradient noise in future gravitational wave detectors.

N.Ibrahim characterizes thermo-optic noise in high-performance mirror coatings of the type used in Advanced LIGO. To characterize thermo-optic noise, she measures the change in …


Trace Element Geochemistry And Nd-Sr Isotope Systematics Of Scheelite From The Thunder Creek And 144 Gap Deposits, Timmins, Ontario: Implications For Timing And Genesis Of Gold, Annika Van Kessel Oct 2018

Trace Element Geochemistry And Nd-Sr Isotope Systematics Of Scheelite From The Thunder Creek And 144 Gap Deposits, Timmins, Ontario: Implications For Timing And Genesis Of Gold, Annika Van Kessel

Electronic Thesis and Dissertation Repository

The age of the youngest gold event at the Timmins West Mine is unknown. Scheelite geochemistry and geochronology at the TWM were constrained using WDS and EDS mapping, LA-ICPMS and MC-ICPMS analytical techniques. Trace element analyses by LA-ICPMS revealed scheelites mineralized from a common and oxidized fluid. Samarium-Neodymium isotopic analyses of 15 scheelite grains yielded a linear regression isochron with a corresponding age of 2587 +/- 49 Ma (MSWD = 2.5) and εNdi, calculated from CHUR, of 1.01 ± 0.11 (2SD). A second internal isochron from a single scheelite grain yielded an age of 2516 +/- 88 Ma (MSWD = …


Systems Evolution And Engineering Thermodynamics, Terry Bristol Oct 2018

Systems Evolution And Engineering Thermodynamics, Terry Bristol

Systems Science Friday Noon Seminar Series

Despite impressive contributions, the philosophical foundations of systems theory remain in flux. In the practical context, the proper understanding of the relation of the systems framework to classical mechanics and quantum theory remains unresolved.


I argue our understanding of systems theory is advanced by recognizing the crucial link to engineering and thermodynamics. Engineering thermodynamics is more general than the historically dominant ‘rational mechanical’ thermodynamics of Clausius, Boltzmann, the Entropy Cult (viz. Jaynes’s MEP) and the recent information theory.

That systems theory’s philosophical foundations are in a philosophy of engineering and an engineering worldview should be no surprise, given the modern …


On Robust Colorings Of Hamming-Distance Graphs, Isaiah Harney, Heide Gluesing-Luerssen Oct 2018

On Robust Colorings Of Hamming-Distance Graphs, Isaiah Harney, Heide Gluesing-Luerssen

Mathematics Faculty Publications

Hq(n, d) is defined as the graph with vertex set Znq and where two vertices are adjacent if their Hamming distance is at least d. The chromatic number of these graphs is presented for various sets of parameters (q, n, d). For the 4-colorings of the graphs H2(n, n − 1) a notion of robustness is introduced. It is based on the tolerance of swapping colors along an edge without destroying properness of the coloring. An explicit description of the maximally robust 4-colorings of …


Nutrient Addition And Drought Interact To Change The Structure And Decrease The Functional Diversity Of A Mediterranean Grassland, Carla Nogueira, Alice Nunes, Miguel N. Bugalho, Cristina Branquinho, Rebecca L. Mcculley, Maria Conceição Caldeira Oct 2018

Nutrient Addition And Drought Interact To Change The Structure And Decrease The Functional Diversity Of A Mediterranean Grassland, Carla Nogueira, Alice Nunes, Miguel N. Bugalho, Cristina Branquinho, Rebecca L. Mcculley, Maria Conceição Caldeira

Plant and Soil Sciences Faculty Publications

Anthropogenic activities are increasing nutrient availability and altering precipitation regimes. This may lead to critical changes in grasslands functioning. This is particularly important for grasslands in the Mediterranean Basin that have evolved in nutrient poor soils, and where more frequent and prolonged droughts are projected to occur. However, there is limited knowledge regarding the interacting effects of multiple nutrient inputs and rainfall variability on the plant functional structure and diversity of Mediterranean grasslands. We conducted a nutrient addition experiment in a Mediterranean grassland during four contrasting precipitation years. We established four treatments that varied in the number of added nutrients, …


The Firece Green Fire: Vol. 9 Issue 5, Wofford College Environmental Studies Program Oct 2018

The Firece Green Fire: Vol. 9 Issue 5, Wofford College Environmental Studies Program

The Fierce Green Fire

No abstract provided.


Tunable Two-Dimensional Dirac Nodal Nets, Ding-Fu Shao, Shu-Hui Zhang, Xiaoqian Dang, Evgeny Y. Tsymbal Oct 2018

Tunable Two-Dimensional Dirac Nodal Nets, Ding-Fu Shao, Shu-Hui Zhang, Xiaoqian Dang, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Nodal-line semimetals are characterized by symmetry-protected band crossing lines and are expected to exhibit nontrivial electronic properties. Connections of the multiple nodal lines, resulting in nodal nets, chains, or links, are envisioned to produce even more exotic quantum states. In this work, we propose a feasible approach to realize tunable nodal-line connections in real materials. We show that certain space group symmetries support the coexistence of the planar symmetry-enforced and accidental nodal lines, which are robust to spin-orbit coupling and can be tailored into intricate patterns by chemical substitution, pressure, or strain. Based on first-principles calculations, we identify nonsymmorphic centrosymmetric …


Excess Electron Screening Of Remote Donors And Mobility In Modern Gaas/Algaas Heterostructures, M. Sammon, Tianran Chen, B. I. Shklovskii Oct 2018

Excess Electron Screening Of Remote Donors And Mobility In Modern Gaas/Algaas Heterostructures, M. Sammon, Tianran Chen, B. I. Shklovskii

Physics & Engineering Faculty Publications

In modern GaAs/AlxGa1−xAs heterostructures with record high mobilities, a two-dimensional electron gas (2DEG) in a quantum well is provided by two remote donor δ-layers placed on both sides of the well. Each δ-layer is located within a narrow GaAs layer, flanked by narrow AlAs layers which capture excess electrons from donors but leave each of them localized in a compact dipole atom with a donor. Still excess electrons can hop between host donors to minimize their Coulomb energy. As a result they screen the random potential of donors dramatically. We numerically model the pseudoground state of excess electrons at a …


Multicolor Blackbody Emission In Grb 081221, Shu-Jin Hou, Bin-Bin Zhang, Yan-Zhi Meng, Xue-Feng Wu, En-Wei Liang, Hou-Jun Lü, Tong Liu, Yun-Feng Liang, Lin Lin, Rui-Jing Lu, Jin-Shu Huang, Bing Zhang Oct 2018

Multicolor Blackbody Emission In Grb 081221, Shu-Jin Hou, Bin-Bin Zhang, Yan-Zhi Meng, Xue-Feng Wu, En-Wei Liang, Hou-Jun Lü, Tong Liu, Yun-Feng Liang, Lin Lin, Rui-Jing Lu, Jin-Shu Huang, Bing Zhang

Physics & Astronomy Faculty Research

The radiation mechanism of the prompt emission of gamma-ray bursts (GRBs) remains an open question. Although their spectra are usually well fitted with the empirical Band function, which is widely believed to be fully nonthermal and interpreted as an optically thin synchrotron emission, accumulating evidence shows that a thermal component actually exists. In this paper, a multicolor blackbody (mBB) model is proposed for the time-integrated spectrum of GRB 081221 by assuming a power-law distribution of the thermal luminosities with temperature, which manifests photospheric emissions from a different radius and/or angle. The effects of the minimum temperature kT min, the maximum …


Math Active Learning Lab: Math 93 Notebook, Michele Iiams, Gwennie Byron Oct 2018

Math Active Learning Lab: Math 93 Notebook, Michele Iiams, Gwennie Byron

Open Educational Resources

This course notebook has been designed for students of Math 93 (Algebra Prep III) at the University of North Dakota. It has been designed to help you get the most out of the ALEKS resources and your time.

  • Topics in the Notebook are organized by weekly learning module.
  • Space for notes from ALEKS learning pages, e-book and videos directs you to essential concepts.
  • Examples and “You Try It” problems have been carefully chosen to help you focus on these essential concepts.
  • Completed Notebook is an invaluable tool when studying for exams.


Veritas And Fermi-Lat Observations Of Tev Gamma-Ray Sources Discovered By Hawc In The 2hwc Catalog, P. T. Reynolds, Et Al Oct 2018

Veritas And Fermi-Lat Observations Of Tev Gamma-Ray Sources Discovered By Hawc In The 2hwc Catalog, P. T. Reynolds, Et Al

Physical Sciences Publications

The High Altitude Water Cherenkov (HAWC) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100 GeV) gamma-ray sources based on 507 days of observation. Among these, 19 sources are not associated with previously known teraelectronvolt (TeV) gamma-ray sources. We have studied 14 of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1 TeV–30 TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected 14 …


Bifurcation Of Plankton Community And Its Impact On Dms Distribution In The Southern Ocean, Kelin Zhuang Oct 2018

Bifurcation Of Plankton Community And Its Impact On Dms Distribution In The Southern Ocean, Kelin Zhuang

Earth & Environmental Sciences Datasets

Submitted to Journal of Geophysical Research Biogeosciences Title: Bifurcation of plankton community and its impact on DMS distribution in the Southern Ocean - A Simulated Response to Elevated CO2 Radiative Forcing Data and code


P-T-X Constraints On Ilmenite Unit Cell And Relationship To Kimberlitic And Non-Kimberlitic Sources, Mitchell R. Galarneau Oct 2018

P-T-X Constraints On Ilmenite Unit Cell And Relationship To Kimberlitic And Non-Kimberlitic Sources, Mitchell R. Galarneau

Electronic Thesis and Dissertation Repository

This research investigates the mineral ilmenite, focusing on the relationship between crystal structure and geochemical and/or pressure data. Ilmenites were obtained from diamond-rich and diamond-poor kimberlites and non-kimberlitic localities, to discriminate between these populations. Crystallographic results showed a delineation between kimberlitic and non-kimberlitic ilmenites at a c-axis value of 14.02 (±0.01) Å. Adding geochemistry and pressure enhances the separation of kimberlitic and non-kimberlitic samples; however, this isn’t the case for diamond-rich versus diamond-poor kimberlites, even with three-dimensional and cluster analyses. A subset of kimberlitic ilmenites (manganese rich) were found with c-axis values and geochemical concentrations similar to non-kimberlitic ilmenites.

By …


Characterizing Ice-Wedge Polygon Geomorphology In The Haughton Impact Structure, Devon Island, Jordan Hawkswell Oct 2018

Characterizing Ice-Wedge Polygon Geomorphology In The Haughton Impact Structure, Devon Island, Jordan Hawkswell

Electronic Thesis and Dissertation Repository

Ice-wedge polygon networks are a common feature in periglacial environments formed through thermal contraction cracking and snowmelt infiltration. Polygons of similar morphology are ubiquitous throughout the mid-latitudes of Mars and are believed to have formed through thermal contraction processes. This study aims to characterize the polygons on Devon Island in the Canadian Arctic and the significant variations in geomorphology they display. The study uses LiDAR data to map, analyse, and compare three sites of polygonal terrain. Variations in polygon morphology such as size and orthogonality are observed in the relatively small study area. The results show that polygon morphologic variations …


High Resolution Ion Beam Investigations Of The Mechanisms Of Titanium Anodization, Mitchell A. Brocklebank Oct 2018

High Resolution Ion Beam Investigations Of The Mechanisms Of Titanium Anodization, Mitchell A. Brocklebank

Electronic Thesis and Dissertation Repository

The unique behaviour of thin films, and their surfaces and interfaces, significantly impact material and device properties. Probing these structures with ion beams (IB) provides quantitative composition and thicknesses measurements. In this dissertation, the IB techniques of medium energy ion scattering (MEIS), nuclear reaction profiling (NRP) and Rutherford backscattering spectrometry (RBS) are used to analyze energy losses in ultra-thin films, as well as elucidate the mechanisms of anodic film growth.

Accurate stopping cross sections of protons, ε, in the medium energy range (50-170 kV) often show deviations from Bragg’s rule. Here, εTi, εSi, and εTiO2 …


Weather And Climate Summary And Forecast: October 2018 Report, Gregory V. Jones Oct 2018

Weather And Climate Summary And Forecast: October 2018 Report, Gregory V. Jones

Linfield University Wine Studies Reports

This report provides a summary of the weather and climate forecast for October 2018. It includes forecast information specific to the Pacific Northwest and the western United States, as well as forecast information for other portions of the United States and abroad.


The Santa Clara, 2018-10-04, Santa Clara University Oct 2018

The Santa Clara, 2018-10-04, Santa Clara University

The Santa Clara

No abstract provided.


Season-Ahead Forecasting Of Water Storage And Irrigation Requirements – An Application To The Southwest Monsoon In India, Arun Ravindranath, Naresh Devineni, Upmanu Lall, Paulina Concha Larrauri Oct 2018

Season-Ahead Forecasting Of Water Storage And Irrigation Requirements – An Application To The Southwest Monsoon In India, Arun Ravindranath, Naresh Devineni, Upmanu Lall, Paulina Concha Larrauri

Publications and Research

Water risk management is a ubiquitous challenge faced by stakeholders in the water or agricultural sector. We present a methodological framework for forecasting water storage requirements and present an application of this methodology to risk assessment in India. The application focused on forecasting crop water stress for potatoes grown during the monsoon season in the Satara district of Maharashtra. Pre-season large-scale climate predictors used to forecast water stress were selected based on an exhaustive search method that evaluates for highest ranked probability skill score and lowest root-mean-squared error in a leave-one-out cross-validation mode. Adaptive forecasts were made in the years …


Thomson, Patrick Henry, 1819-1901 (Sc 3266), Manuscripts & Folklife Archives Oct 2018

Thomson, Patrick Henry, 1819-1901 (Sc 3266), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid only for Manuscripts Small Collection 3266. Farm journal kept by Patrick Henry Thomson of Hurricane Hall, Fayette County, Kentucky. He records daily temperatures and farm operations, and makes occasional mention of his and wife Julia's activities. A loose item dated 10 November 1852 gives him notice of a meeting in regards to the recent fire at the county courthouse.


Using Machine Learning To Accurately Predict Ambient Soundscapes From Limited Data Sets, Katrina Lynn Pedersen Oct 2018

Using Machine Learning To Accurately Predict Ambient Soundscapes From Limited Data Sets, Katrina Lynn Pedersen

Theses and Dissertations

The ability to accurately characterize the soundscape, or combination of sounds, of diverse geographic areas has many practical implications. Interested parties include the United States military and the National Park Service, but applications also exist in areas such as public health, ecology, community and social justice noise analyses, and real estate. I use an ensemble of machine learning models to predict ambient sound levels throughout the contiguous United States. Our data set consists of 607 training sites, where various acoustic metrics, such as overall daytime L50 levels and one-third octave frequency band levels, have been obtained. I have data for …


On Biospeleothems From A Venezuelan Tepui Cave: U-Th Dating, Growth Rates, And Morphology, Joyce Lundberg, Charles Brewer-Carías, Donald A. Mcfarlane Oct 2018

On Biospeleothems From A Venezuelan Tepui Cave: U-Th Dating, Growth Rates, And Morphology, Joyce Lundberg, Charles Brewer-Carías, Donald A. Mcfarlane

International Journal of Speleology

Seven silica biospeleothems from Cueva Charles Brewer, Chimantá Plateau, Venezuela have been successfully U-Th dated despite very low U and high detrital Th concentrations. Growth rates are low, between ~100 to ~800 µm/ka, and are greater closer to water level. Dates in unaltered material are in good stratigraphic order, but secondary silicification may compromise the U-Th system, yielding unreliable sequences of ages. Detritally-enriched layers correlate with global climate cycles of the Late Quaternary, in particular the cooler, drier phases of MIS 5d, 5a, and 4. SEM studies indicate that the peloidal material is made up of silica nano-particles assembled to …


Near-Earth Asteroid Resources: Review And Analogue Study Of Highly Siderophile Elements In Main-Group Pallasites, Liam R. J. Innis Oct 2018

Near-Earth Asteroid Resources: Review And Analogue Study Of Highly Siderophile Elements In Main-Group Pallasites, Liam R. J. Innis

Electronic Thesis and Dissertation Repository

The potential for NEAs as targets for space resource utilization has been explored. Water and PGEs have been identified as resources with potential profitability in existing markets. Of the ~18,000 asteroids in the known NEA catalogue, seven and three are expected to be prospective for water and PGEs when accounting for size, resource concentration, and accessibility. Improved NEA discovery campaigns, with emphasis on spectroscopy, and advancements in space transportation and autonomous robotic technology are crucial to future success of NEA resource utilization. LA-ICP-MS was used to evaluate main-group pallasites (PMG) for PGE potential. Bulk metal concentrations of most PGEs are …


Au@H-Al2o3 Analogic Yolk–Shell Nanocatalyst For Highly Selective Synthesis Of Biomass-Derived D-Xylonic Acid Via Regulation Of Structure Effects, Jiliang Ma, Zewei Liu, Junlong Song, Linxin Zhong, Dequan Xiao, Hongxia Xi, Xuehui Li, Runcang Sun, Xinwen Peng Oct 2018

Au@H-Al2o3 Analogic Yolk–Shell Nanocatalyst For Highly Selective Synthesis Of Biomass-Derived D-Xylonic Acid Via Regulation Of Structure Effects, Jiliang Ma, Zewei Liu, Junlong Song, Linxin Zhong, Dequan Xiao, Hongxia Xi, Xuehui Li, Runcang Sun, Xinwen Peng

Chemistry and Chemical Engineering Faculty Publications

Selective oxidation of biomass-based monosaccharides into value-added sugar acids is highly desired, but limited success of producing D-xylonic acid has been achieved. Herein, we report an efficient catalyst system, viz., Au nanoparticles anchored on the inner walls of hollow Al2O3 nanospheres (Au@h- Al2O3), which could catalyze the selective oxidation of D-xylose into D-xylonic acid under base-free conditions. The mesoporous Al2O3 shell as the adsorbent first adsorbed D-xylose. Then, the interface of Au nanoparticles and Al2O3 as active sites spontaneously dissociated O2, and …