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Physical Sciences and Mathematics Commons

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University of Louisville

2019

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Articles 1 - 30 of 85

Full-Text Articles in Physical Sciences and Mathematics

Seer: An Explainable Deep Learning Midi-Based Hybrid Song Recommender System, Khalil Damak, Olfa Nasraoui Dec 2019

Seer: An Explainable Deep Learning Midi-Based Hybrid Song Recommender System, Khalil Damak, Olfa Nasraoui

Faculty Scholarship

State of the art music recommender systems mainly rely on either matrix factorization-based collaborative filtering approaches or deep learning architectures. Deep learning models usually use metadata for content-based filtering or predict the next user interaction by learning from temporal sequences of user actions. Despite advances in deep learning for song recommendation, none has taken advantage of the sequential nature of songs by learning sequence models that are based on content. Aside from the importance of prediction accuracy, other significant aspects are important, such as explainability and solving the cold start problem. In this work, we propose a hybrid deep learning …


Electrochemical Determination Of Surface Area-To-Volume Ratio For Metal Nanoparticle Analysis., Jay Narayan Sharma Dec 2019

Electrochemical Determination Of Surface Area-To-Volume Ratio For Metal Nanoparticle Analysis., Jay Narayan Sharma

Electronic Theses and Dissertations

This dissertation describes an electrochemical approach for measuring the surface area-to-volume ratio (SA/V) of electrode-attached metal nanoparticles (NPs), which was used to analyze their size, aggregation state, and porosity. This dissertation further describes the effect of the metal NP electrode assembly method on the SA/V, which is related to metal NP catalytic activity and stability. Cyclic voltammetry (CV) in acid electrolyte followed by anodic stripping voltammetry (ASV) in KBr electrolyte allows the electrochemical measurement of the SA/V of electrode-attached Au nanospheres (NSs). In CV, the forward scan produces a thin surface Au2O3 layer on the Au NSs. …


An Electrochemical Instrument For The Analysis Of Heavy Metals In Water Via Anodic Stripping Coulometry For Applications In Remote Sensing., Kelsey Lynn Kaht Dec 2019

An Electrochemical Instrument For The Analysis Of Heavy Metals In Water Via Anodic Stripping Coulometry For Applications In Remote Sensing., Kelsey Lynn Kaht

Electronic Theses and Dissertations

From the high levels of arsenic in groundwater in Bangladesh to the lead contamination of drinking water in Flint, Michigan, there are incidents across the globe that highlight the need for a reliable instrument capable of monitoring heavy metals remotely and continuously in a variety of geographical locations. Typical instrumentation for water analysis, such as ICP and AAS, must be housed in a central lab and relies on an operator traveling to the collection site, obtaining a sample, and transporting it back to the lab. This analysis provides a snapshot of the water quality that is limited to the specific …


Statistical Methods For Estimating And Testing Treatment Effect For Multiple Treatment Groups In Observational Studies., Xiaofang Yan Dec 2019

Statistical Methods For Estimating And Testing Treatment Effect For Multiple Treatment Groups In Observational Studies., Xiaofang Yan

Electronic Theses and Dissertations

Note: Abstract would not save due to an issue with some of the characters.


Laser Spectroscopy Investigations Of Jet-Cooled Metal-Containing Free Radicals., Anam Chandra Paul Dec 2019

Laser Spectroscopy Investigations Of Jet-Cooled Metal-Containing Free Radicals., Anam Chandra Paul

Electronic Theses and Dissertations

Metal-containing free radicals are important intermediates in metal-surface reactions and the interactions between metals and organic molecules. Among metal-containing free radicals, monovalent derivatives of alkaline earth metals have been extensively investigated by using spectroscopic techniques in a gas phase, mainly in Broida ovens or under supersonic-jet-cooled conditions. In the present study, the results of performed spectroscopic investigations of both metal-containing monoalkoxides (CaOR) and metal oxides (MO) radicals have been reported. Laser-induced fluorescence (LIF) and dispersed fluorescence (DF) spectra of the electronic transition of the calcium CaOR radicals have been obtained under jet-cooled conditions. Complete active space self-consistent field (CASSCF) and …


Laser Spectroscopic Investigations Of Organic Alkoxy And Peroxy Radicals., Md Asmaul Reza Dec 2019

Laser Spectroscopic Investigations Of Organic Alkoxy And Peroxy Radicals., Md Asmaul Reza

Electronic Theses and Dissertations

Understanding the mechanism of combustion reactions is key for advancing internal combustion engine design, improving the efficiency of ignition chemical reactions, and reducing pollutant formation. In order to model the extremely complicated chemical kinetics of combustion processes, it is critical to detect and identify transient reactive chemical intermediates, particularly free radicals. Hence, it needs to be fully understood the gas-phase chemistry of organic compounds in the lower atmosphere. Over the past fifty years, parallel advancement in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role of organic compounds in the atmosphere. Combustion chemistry …


Oxygen Deficient Perovskites: Effect Of Structure On Electrical Conductivity, Magnetism And Electrocatalytic Activity., Ram Krishna Hona Dec 2019

Oxygen Deficient Perovskites: Effect Of Structure On Electrical Conductivity, Magnetism And Electrocatalytic Activity., Ram Krishna Hona

Electronic Theses and Dissertations

The present thesis deals with the synthesis and study of the physico-chemical properties of perovskite based oxide materials. Several novel oxygen deficient perovskites (ODP) have been synthesized by conventional solid state synthesis method. The novel compounds are CaSrFe2O6-δ, CaSrFeCoO6-δ, Ca2Fe1.5Ga0.5O5, CaSrFeGaO5 and BaSrFe2O5. Their magnetic, charge transport and electrocatalytic properties have been studied. Structural effect on electrical conductivity, magnetic and electrocatalytic properties have been studied in some series of ODPs. CaSrFe2O6-δ, CaSrFeCoO6-δ, Ca2Fe …


Gc×Gc-Ms And Parallel 2dlc-Ms Based Untargeted Metabolomics., Md Aminul Islam Prodhan Dec 2019

Gc×Gc-Ms And Parallel 2dlc-Ms Based Untargeted Metabolomics., Md Aminul Islam Prodhan

Electronic Theses and Dissertations

Untargeted metabolomics aims to analyze as many metabolites as possible in a biological system. Due to the vast complexity of the metabolome, bioanalytical platforms have been developed for untargeted metabolomics. While comprehensive two-dimensional gas chromatography mass spectrometry (GC×GC-MS) has been used in different scientific fields, its use in untargeted metabolomics is limited due to several challenges, such as complicated data analysis and limited accuracy of metabolite identification. Two-dimensional liquid chromatography mass spectrometry (2DLC-MS) has also been employed in untargeted metabolomics, but with limited metabolite coverage. This dissertation describes the efforts in developing new data analysis algorithms to improve the accuracy …


Laser Spectroscopy Investigations On Molecular And Free Radicals Dynamics., Hamzeh Telfah Dec 2019

Laser Spectroscopy Investigations On Molecular And Free Radicals Dynamics., Hamzeh Telfah

Electronic Theses and Dissertations

Studying molecular dynamics and chemical kinetics is important to understand the chemical behavior of renewable energy sources. Laser spectroscopy techniques are powerful tools for the identification and diagnosis of such processes. In this dissertation, using our laser spectroscopy techniques, biofuels and solar energy were targeted as renewable energy sources study. We have studied the ultrafast exciton dynamics for a series of methylammonium lead bromide (CH3NH3PbBr3) nanostructures, nanocrystals (NCs, 0D), nanowires (NWs, 1D), and nanoplatelets (NPs, 2D) as a promising solar energy materials.1-2 Aided by analysis of UV−visible absorption and photoluminescence spectra, features in the transient absorption (TA) spectra are assigned …


Stability And Reactivity Analysis Of Single Metal And Bimetallic Nanostructures By Anodic Stripping Voltammetry., Dhruba Kumar Pattadar Dec 2019

Stability And Reactivity Analysis Of Single Metal And Bimetallic Nanostructures By Anodic Stripping Voltammetry., Dhruba Kumar Pattadar

Electronic Theses and Dissertations

This dissertation has two main themes. The first involves studies aimed at developing anodic stripping voltammetry (ASV) as an analytical tool to characterize metal nanoparticles (NPs), with a focus on the size and aggregate structure of single metal NPs and the composition and atomic arrangement of bimetallic NPs. The second main theme involves studies that use ASV and electrochemical surface area-to-volume (SA/V) measurements to study the unique reactivity and transformations of single metal and bimetallic NPs. The transformations involve size and composition changes in response to ozone and electrochemical potential. Reactions involve size dependent galvanic exchange and electrocatalytic activity. The …


Sustainable Solutions, Fall/Winter 2020, Issue 41 Nov 2019

Sustainable Solutions, Fall/Winter 2020, Issue 41

Sustain Magazine

No abstract provided.


Effect Of Galaxy Mergers On Star-Formation Rates, W. J. Pearson, L. Wang, M. Alpaslan, I. Baldry, M. Bilicki, M. J.I. Brown, M. W. Grootes, Benne W. Holwerda, T. D. Kitching, S. Kruk, F. F.S. Van Der Tak Nov 2019

Effect Of Galaxy Mergers On Star-Formation Rates, W. J. Pearson, L. Wang, M. Alpaslan, I. Baldry, M. Bilicki, M. J.I. Brown, M. W. Grootes, Benne W. Holwerda, T. D. Kitching, S. Kruk, F. F.S. Van Der Tak

Faculty Scholarship

Context. Galaxy mergers and interactions are an integral part of our basic understanding of how galaxies grow and evolve over time. However, the effect that galaxy mergers have on star-formation rates (SFRs) is contested, with observations of galaxy mergers showing reduced, enhanced, and highly enhanced star formation. Aims. We aim to determine the effect of galaxy mergers on the SFR of galaxies using statistically large samples of galaxies, totalling over 200 000, which is over a large redshift range from 0.0 to 4.0. Methods. We trained and used convolutional neural networks to create binary merger identifications (merger or non-merger) in …


Default Parallels: The Science Potential Of Jwst Parallel Observations During Tso Primary Observations, Benne W. Holwerda, Jonathan Fraine, Nelly Mouawad, Joanna S. Bridge Nov 2019

Default Parallels: The Science Potential Of Jwst Parallel Observations During Tso Primary Observations, Benne W. Holwerda, Jonathan Fraine, Nelly Mouawad, Joanna S. Bridge

Faculty Scholarship

The James Webb Space Telescope (JWST) will observe several stars for long cumulative durations while pursuing exoplanets as primary science targets for both Guaranteed Time Observations (GTO) and very likely General Observer (GO) programs. Here we argue in favor of an automatic default parallel program to observe, e.g., using the F200W/F277W filters or grism of NIRCAM/NIRISS in order to find high redshift (z (Formula Presented) 10) galaxies, cool red/brown dwarf substellar objects, solar system objects, and observations of serendipitous planetary transits. We argue here the need for automated exploratory astrophysical observations with unused JWST instruments during these long-duration exoplanet observations. …


Star-Forming, Rotating Spheroidal Galaxies In The Gama And Sami Surveys, Amanda J. Moffett, Steven Phillipps, Aaron S.G. Robotham, Simon P. Driver, Malcolm N. Bremer, Luca Cortese, O. Ivy Wong, Sarah Brough, Michael J.I. Brown, Julia J. Bryant, Christopher J. Conselice, Scott M. Croom, Koshy George, Greg Goldstein, Michael Goodwin, Benne W. Holwerda, Andrew M. Hopkins, Iraklis S. Konstantopoulos, Jon S. Lawrence, Nuria P.F. Lorente, Anne M. Medling, Matt S. Owers, Kevin A. Pimbblet, Samuel N. Richards, Sarah M. Sweet, Jesse Van De Sande Oct 2019

Star-Forming, Rotating Spheroidal Galaxies In The Gama And Sami Surveys, Amanda J. Moffett, Steven Phillipps, Aaron S.G. Robotham, Simon P. Driver, Malcolm N. Bremer, Luca Cortese, O. Ivy Wong, Sarah Brough, Michael J.I. Brown, Julia J. Bryant, Christopher J. Conselice, Scott M. Croom, Koshy George, Greg Goldstein, Michael Goodwin, Benne W. Holwerda, Andrew M. Hopkins, Iraklis S. Konstantopoulos, Jon S. Lawrence, Nuria P.F. Lorente, Anne M. Medling, Matt S. Owers, Kevin A. Pimbblet, Samuel N. Richards, Sarah M. Sweet, Jesse Van De Sande

Faculty Scholarship

The Galaxy And Mass Assembly (GAMA) survey has morphologically identified a class of 'Little Blue Spheroid' (LBS) galaxies whose relationship to other classes of galaxies we now examine in detail. Considering a sample of 868 LBSs, we find that such galaxies display similar but not identical colours, specific star formation rates, stellar population ages, massto- light ratios, and metallicities to Sd-Irr galaxies. We also find that LBSs typically occupy environments of even lower density than those of Sd-Irr galaxies, where ∼65 per cent of LBS galaxies live in isolation. Using deep, high-resolution imaging from VST KiDS and the new Bayesian, …


Environmentally Responsible Land Use, Spring/Summer 2010, Issue 22 Sep 2019

Environmentally Responsible Land Use, Spring/Summer 2010, Issue 22

Sustain Magazine

No abstract provided.


Sustainable Communities, Fall/Winter 2010, Issue 21 Sep 2019

Sustainable Communities, Fall/Winter 2010, Issue 21

Sustain Magazine

No abstract provided.


Sustainable Building, Spring/Summer 2009, Issue 20 Sep 2019

Sustainable Building, Spring/Summer 2009, Issue 20

Sustain Magazine

No abstract provided.


Environmental History, Fall/Winter 2009, Issue 19 Sep 2019

Environmental History, Fall/Winter 2009, Issue 19

Sustain Magazine

No abstract provided.


Student Research, Spring/Summer 2008, Issue 18 Sep 2019

Student Research, Spring/Summer 2008, Issue 18

Sustain Magazine

No abstract provided.


Evolving Pollution Prevention, Fall/Winter 2008, Issue 17 Sep 2019

Evolving Pollution Prevention, Fall/Winter 2008, Issue 17

Sustain Magazine

No abstract provided.


Climate Change, Spring/Summer 2007, Issue 16 Sep 2019

Climate Change, Spring/Summer 2007, Issue 16

Sustain Magazine

No abstract provided.


Our Energy Future, Fall/Winter 2007, Issue 15 Sep 2019

Our Energy Future, Fall/Winter 2007, Issue 15

Sustain Magazine

No abstract provided.


Land Conservation, Spring/Summer 2006, Issue 14 Sep 2019

Land Conservation, Spring/Summer 2006, Issue 14

Sustain Magazine

No abstract provided.


Pollution And Heart Disease, Fall/Winter 2006, Issue 13 Sep 2019

Pollution And Heart Disease, Fall/Winter 2006, Issue 13

Sustain Magazine

No abstract provided.


Green Cities, Spring/Summer 2005, Issue 12 Sep 2019

Green Cities, Spring/Summer 2005, Issue 12

Sustain Magazine

No abstract provided.


Global Sustainability, Fall/Winter 2005, Issue 11 Sep 2019

Global Sustainability, Fall/Winter 2005, Issue 11

Sustain Magazine

No abstract provided.


Environmental Justice, Spring/Summer 2004, Issue 10 Sep 2019

Environmental Justice, Spring/Summer 2004, Issue 10

Sustain Magazine

No abstract provided.


Kentucky's Environmental Future, Fall/Winter 2004, Issue 9 Sep 2019

Kentucky's Environmental Future, Fall/Winter 2004, Issue 9

Sustain Magazine

No abstract provided.


Urban Ecology, Spring/Summer 2003, Issue 8 Sep 2019

Urban Ecology, Spring/Summer 2003, Issue 8

Sustain Magazine

No abstract provided.


Urban Regeneration, Fall/Winter 2003, Issue 7 Sep 2019

Urban Regeneration, Fall/Winter 2003, Issue 7

Sustain Magazine

No abstract provided.