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Articles 19411 - 19440 of 302419

Full-Text Articles in Physical Sciences and Mathematics

Vibrations Reduction Of A Clamped- Clamped Micro-Beam Via Positive Position Feedback Controller, H. Mosaa, M. Kamel, H. El Gohry, L. S. Diab, H. M. Shawky Jan 2023

Vibrations Reduction Of A Clamped- Clamped Micro-Beam Via Positive Position Feedback Controller, H. Mosaa, M. Kamel, H. El Gohry, L. S. Diab, H. M. Shawky

Al-Azhar Bulletin of Science

This manuscript displays the vibrations reduction of a clamped- clamped micro-beam subjected to an excitation external force via applying the positive position feedback (PPF) controller. The approximate solutions of the whole system are obtained up to the second order approximation with the help of the multiple scale perturbation technique (MSP). The Stability analysis is studied by utilizing the frequency response equations near the simultaneous condition .Time histories and response curves figures before and after control of the whole system are examined numerically using Rung-Kutta Fourth-order method (Maple(16) software and Matlab 7.7(R2014) software. Numerical results of the influences of different parameters …


A Numerical Approach To Solve The Initial-Value Problem Of Two-Body With Universal Variable, Ahmed B. Yassen, Waleed N. Ahmed, Ahmed H. Ibrahim, Abdelaziz A. Bakry, Hany R. Dwidar Jan 2023

A Numerical Approach To Solve The Initial-Value Problem Of Two-Body With Universal Variable, Ahmed B. Yassen, Waleed N. Ahmed, Ahmed H. Ibrahim, Abdelaziz A. Bakry, Hany R. Dwidar

Al-Azhar Bulletin of Science

The solution of the initial-value problem of two-body gives inaccurate final state predictions for the orbital motions of artificial satellites. This is due to the presence of singularities and the poor selection of variables. In the current study, we numerically investigated the initial-value problem using the universal anomaly approach. To clarify the problem under concern, we carried out several numerical examples using a homemade software package. We considered five space missions, around the two planets Earth and Venus, which represent circular, near circular and ellipse orbits. We showed that the universal anomaly approach facilitates the numerical and analytical treatments of …


Synthesis Of New Ligand-Based Phosphazo Ring And Its Transition Metal Complexes As Cancer Inhibitor: Spectroscopic, Dft, Antimicrobial, And Molecular Docking Investigations, Asmaa A. Hamed, Ahmed A. El-Sherif, Carmen M. Sharaby, Yousry A. Ammar, Mona F. Amine Jan 2023

Synthesis Of New Ligand-Based Phosphazo Ring And Its Transition Metal Complexes As Cancer Inhibitor: Spectroscopic, Dft, Antimicrobial, And Molecular Docking Investigations, Asmaa A. Hamed, Ahmed A. El-Sherif, Carmen M. Sharaby, Yousry A. Ammar, Mona F. Amine

Al-Azhar Bulletin of Science

A condensation between 2-sulfanilamidopyrimidine and a p-toluidine dimer of cyclodiazadiphosphetidine resulted in the formation of a new ligand, 2,2,4,4-tetrachloro-1,3-di-[p-tolyl]-2,4-di-[N-(pyrimidin-2-yl) benzenesulfonamide]-1,3,2,4-diazadiphosphetidine, (H2L). We investigated the chemical behavior of the newly prepared ligand was investigated by treating it with some chosen metal ions at a stoichiometric ratio of 1:2 (L:M), where M = Fe(III), Fe(II), Cu(II), Zn(II), Cd(II), and Ag(I), to provide colored complexes with accepted yields. Then, we characterized the ligand and related complexes using spectroscopic and analytical techniques. Investigations revealed that the geometrical structure of the complexes was octahedral, except for the silver complex was tetrahedral. From the spectral analyses, …


Identification Of Identical Bands And Energy Staggering Phenomena In Superdeformed Nuclei In A=190 Mass Region In The Framework Of A Novel Proposed Simple Formula, Farid.A. Elmanakely, Gamal.S.M. Ahmed, Shimaa Abdelfattah, Ali. M. Khalaf Jan 2023

Identification Of Identical Bands And Energy Staggering Phenomena In Superdeformed Nuclei In A=190 Mass Region In The Framework Of A Novel Proposed Simple Formula, Farid.A. Elmanakely, Gamal.S.M. Ahmed, Shimaa Abdelfattah, Ali. M. Khalaf

Al-Azhar Bulletin of Science

A total of eleven superdeformed rotational bands (SDRB’s) in the A=190 mass zone were described in the framework of a novel proposed simple phenomenological rotational formula as outcome of collective model. The proposed model contains the original pure rotation limit AI (I+1) plus perturbation term proportionate to the cubic power of the spin I. The bandhead spins and the model parameters were selected by a best fit method, utilizing a computerized search program to obtain best match between experimental and calculated transition energies. The spin propositions are mostly consistent with the findings of earlier works. The calculated gamma-ray transition energies …


Early Pliocene Arvicolinae And Cricetinae From The Locality Of Afşar, Western Turkey, Panagiotis Skandalos, Koen Lansing, Fatma Arzu Demi̇rel, Mehmet Ci̇hat Alçi̇çek, Serdar Mayda, Francien Dieleman, Lars W. Van Den Hoek Ostende Jan 2023

Early Pliocene Arvicolinae And Cricetinae From The Locality Of Afşar, Western Turkey, Panagiotis Skandalos, Koen Lansing, Fatma Arzu Demi̇rel, Mehmet Ci̇hat Alçi̇çek, Serdar Mayda, Francien Dieleman, Lars W. Van Den Hoek Ostende

Turkish Journal of Earth Sciences

The Afşar section, situated in the Dombayova graben in western Turkey, is one of the key localities for the study of the Pliocene of Anatolia. Two fossiliferous layers yielded micromammal assemblages, including various cricetine and arvicoline species. These include the species Mimomys cf. gracilis, Pliomys sp., Arvicolinae gen. sp. and the cricetines Cricetulus cf. ehiki and Cricetulus sp. in Afşar 1 and Mimomys hassiacus, M. gracilis, Pliomys graecus and Mesocricetus primitivus in Afşar 2. The cooccurence of these species indicates a dry and open spaced habitat. Based on the composition and stage of evolution of the hamster and vole species, …


Calcareous Nannofossils, Planktonic Foraminifera, And Revised Stratigraphy Of The Eocene Çayraz Formation; The Final Stage Of Marine Sedimentation In Central Anatolia, Turkey, Ali̇ Osman Yücel, Ercan Özcan, Rita Catanzariti, Aynur Hakyemez, Aral Okay, Tahsi̇n Atti̇la Çi̇ner, Ali̇ Akin Jan 2023

Calcareous Nannofossils, Planktonic Foraminifera, And Revised Stratigraphy Of The Eocene Çayraz Formation; The Final Stage Of Marine Sedimentation In Central Anatolia, Turkey, Ali̇ Osman Yücel, Ercan Özcan, Rita Catanzariti, Aynur Hakyemez, Aral Okay, Tahsi̇n Atti̇la Çi̇ner, Ali̇ Akin

Turkish Journal of Earth Sciences

New field observations and discovery of calcareous nannofossils and planktonic foraminifera from the 'shallow-marine' Çayraz Formation (Haymana Basin, Central Anatolia), a contributing Eocene section to the shallow benthic zonation (SBZ) in the Tethys, allow us to revise its stratigraphy and establish an integrated biostratigraphic scheme for the first time. The hemipelagic marls in the uppermost part of the Eskipolatlı Formation that underlies the Çayraz Formation yielded nannofossil assemblages of Zone CNE3, pinning down the initiation of the Çayraz shelf system into the 'middle' Ypresian. The prominent marly part (Member B) between the carbonate-clastic packages of the Çayraz Formation with prolific …


Pithonellid Calcitarch Record In The Middle? Cenomanian Derdere-A Member, Se Turkey: Palaeoenvironmental Changes And Stratigraphic Significance, Oğuz Mülayi̇m, İsmai̇l Ömer Yilmaz, Bruno Ferré Jan 2023

Pithonellid Calcitarch Record In The Middle? Cenomanian Derdere-A Member, Se Turkey: Palaeoenvironmental Changes And Stratigraphic Significance, Oğuz Mülayi̇m, İsmai̇l Ömer Yilmaz, Bruno Ferré

Turkish Journal of Earth Sciences

Pithonellid calcitarchs are studied in the organic-rich limestones of the Derdere-A Member from the middle? Cenomanian deposits of SE Turkey for the first time. Little is known about the distribution of pithonellid calcitarchs in the Cretaceous strata of Turkey. Three morphogroups of pithonellid calcitarchs are distinguished: they are represented by Pithonella sphaerica (Kaufmann, 1865) and P. ovalis (Kaufmann, 1865), both dominating the pithonellid assemblages, and by Bonetocardiella conoidea (Bonet, 1956), this latter being less abundant. Compared to the relative abundance of Upper Cretaceous pithonellid calcitarchs in the study area, the diversity is extremely low. The significant increase in abundance of …


Petrological Characteristics Of Gabbroic Intrusions In Southeastern Urmia-Dokhtar Magmatic Belt, Kerman Province, Iran: Evidence For Post-Eocene Mafic Magmatism, Zahra Najafi, Hamid Ahmadipour, Abbas Moradian, Fatemeh Sarjoughian, Kazuo Nakashima Jan 2023

Petrological Characteristics Of Gabbroic Intrusions In Southeastern Urmia-Dokhtar Magmatic Belt, Kerman Province, Iran: Evidence For Post-Eocene Mafic Magmatism, Zahra Najafi, Hamid Ahmadipour, Abbas Moradian, Fatemeh Sarjoughian, Kazuo Nakashima

Turkish Journal of Earth Sciences

At the south of the Bardsir, Kerman province, Iran, the southeastern part of the Urmia-Dokhtar magmatic arc (UDMA), a large number of gabbroic intrusions are intruded into the Eocene lava flows and pyroclastic rocks with the form of small stocks and dykes. In this paper, geochemical variations, magmatic evolutions, and the origin of these intrusions are investigated. The studied intrusions are characterized by fine-grained margins resulting from rapid cooling and flow differentiation. They display porphyritic texture and include coarse-grained clinopyroxene with diopside compositions (Wo = 46.89, En = 40.78, Fs = 12.32), plagioclase with labradorite composition (An = 54.14), and …


New Triassic Finding In Andız Peninsula (İzmir, Western Turkey) And Comparison Of Pre-Neogene Sequences Of Andız And Karaburun Peninsulas: Stratigraphic And Tectonic Implications, İsmai̇l İşi̇ntek Jan 2023

New Triassic Finding In Andız Peninsula (İzmir, Western Turkey) And Comparison Of Pre-Neogene Sequences Of Andız And Karaburun Peninsulas: Stratigraphic And Tectonic Implications, İsmai̇l İşi̇ntek

Turkish Journal of Earth Sciences

This study aims to review the geology of the Andız Peninsula and compare the pre-Neogene Andız succession with the middle part of the Karaburun Peninsula to discuss the nature of the Paleozoic-Mesozoic boundary in the Karaburun Peninsula. The pre-Neogene units of the Andız Peninsula are represented by the Paleozoic Dikendağı, Triassic Gu?vercinlik, and Jurassic Nohutalan Formations. In this study, the Triassic carbonate rocks in the Andız Peninsula are paleontologically defined for the first time. The Megalodont-bearing Gu?vercinlik Formation contains a late Norian-Rhaetian characteristic foraminiferal assemblage consisting of Aulotortus gr. sinuosus, A. tenuis, A. friedli, A. impressus, and Triasina hantkeni. The …


Foraminiferal Micropaleontology Of The Harami Formation (Elazığ, Eastern Turkey), And Reassessment Of Its Age Based On Larger Benthic Foraminifera, Si̇bel Kayğili Jan 2023

Foraminiferal Micropaleontology Of The Harami Formation (Elazığ, Eastern Turkey), And Reassessment Of Its Age Based On Larger Benthic Foraminifera, Si̇bel Kayğili

Turkish Journal of Earth Sciences

The age and depositional environment of the Harami Formation were reevaluated based on the new larger benthic foraminiferal (LBF) data. LBF assemblage including Orbitoides medius (d'Archiac), O. megaloformis Papp and Küpper, O. gruenbachensis Papp, Pseudomphalocyclus blumenthali Meriç, Omphalocyclus macroporus (Lamarck), Sirtina cf. orbitoidiformis Brönnimann and Wirz, Hellenocyclina beotica Reichel, Lepidorbitoides campaniensis Van Gorsel, L. bisambergensis (Jaeger), L. cf. minor (Schlumberger), Pseudosiderolites vidali (Douville), and Siderolites gr. calcitrapoides Lamarck were determined in the formation. Based on this LBF assemblage data, the late Campanian-Maastrichtian age was assigned to the formation. The paleontological and sedimentological data indicate that the Harami Formation was deposited …


Micropaleontological Findings And Absolute Ages Mark The Termination Of The Last Glacial Maximum In The Eastern Mediterranean Region: New Electron Spin Resonance Data From Gediz Delta (Western Turkey), Eki̇n Gökçe Benli̇, Hülya Aslin, İsmai̇l İşi̇ntek, Bi̇rol Engi̇n, Berna Şengöçmen Geçki̇n Jan 2023

Micropaleontological Findings And Absolute Ages Mark The Termination Of The Last Glacial Maximum In The Eastern Mediterranean Region: New Electron Spin Resonance Data From Gediz Delta (Western Turkey), Eki̇n Gökçe Benli̇, Hülya Aslin, İsmai̇l İşi̇ntek, Bi̇rol Engi̇n, Berna Şengöçmen Geçki̇n

Turkish Journal of Earth Sciences

Sediments and fossil content of Gediz Delta (Eastern Aegean Sea-İzmir) were examined from the samples collected from three drilling cores from the west (seaward) to east (landward) of the delta. Each drilling core contains Quarternary marine deposits with a marine fauna of foraminifers, bivalves, gastropods, echinoids, and ostracods at the bottom and Quaternary continental delta deposits at the top. According to our Electron Spin Resonance (ESR) age model marine sediments of the Aegean Sea started to cover the western Gediz Delta area before 19.9 ka (thousand years). Following the Last Glacial Maximum (LGM), after the transgression due to deglaciation occurred …


Plastic Storage In River Sediments Across An Urbanization Gradient In The Ipswich Watershed In Massachusetts, Jackie L. Harris Jan 2023

Plastic Storage In River Sediments Across An Urbanization Gradient In The Ipswich Watershed In Massachusetts, Jackie L. Harris

Honors Theses and Capstones

The importance of plastic pollution research has become apparent as plastic pollution has increased exponentially since its introduction in the 1950s. Plastics mechanically break down into minuscule particles called microplastics, which are plastic particles with a size range of 0.1 micrometers (μm) to 5 millimeters (mm). Most of the research on microplastic pollution has centered around marine ecosystems rather than freshwater ecosystems. More freshwater microplastic research to date is emerging but is still nascent and sparse. Furthermore, the idea that rivers are merely conduits of microplastics to the ocean is even more limited and ignores microplastic loading and retention in …


The Radial Quenching Progression Of Nearby Galaxies, Chenyu Zhao Jan 2023

The Radial Quenching Progression Of Nearby Galaxies, Chenyu Zhao

Theses and Dissertations--Physics and Astronomy

In this dissertation, we explore the spatial distribution of quiescent regions within galaxies using data from the Sloan Digital Sky Survey IV Mapping Nearby Galaxies at Apache Point Observatory (SDSS-IV MaNGA). Our analysis focuses on a radial range spanning from 0.3 R e to 1.2 R e and involves the development of innovative data selection and processing methods. Through this investigation, we identify two prominent types of transition galaxies: central-star-forming galaxies (C-SF galaxies) and central-quiescent galaxies (C-Q galaxies). Notably, we observe a correlation between galaxy mass and the predominant type of transition, with more massive galaxies tending to be C-Q …


Aspects Of Topology In Moiré Graphene, Ahmed Khalifa Jan 2023

Aspects Of Topology In Moiré Graphene, Ahmed Khalifa

Theses and Dissertations--Physics and Astronomy

Moiré materials, such as twisted bilayer graphene, have provided a rich platform for fundamental physics and potential technological applications. Superconductivity,
correlated insulators, and Chern insulators are examples of phenomena that have been found experimentally in moiré systems. The interplay of strong electron-electron interactions and topology lies at the heart of the mechanism driving these phenomena. In this work, we study the topological aspects of moiré graphene materials, such as the valley Chern and Chern insulating phases. To study the topological response of these phases, we construct models to describe the edge states which are the telltale signs of nontrivial topology. …


Investigations Of Epitaxial Heterostructures Of Layered Iridates With Resonant X-Ray Techniques, Sujan Shrestha Jan 2023

Investigations Of Epitaxial Heterostructures Of Layered Iridates With Resonant X-Ray Techniques, Sujan Shrestha

Theses and Dissertations--Physics and Astronomy

In layered 5d transition metal oxides, like Sr2IrO4, strong spin-orbit interaction comparable to the relevant interactions such as electron correlation and crystal field splitting provides fertile ground for emergent non-trivial phenomena. Some of these phenomena include metal-insulator transition, high-temperature superconductivity, and spin-orbit Mott insulator. The ground state is governed by the spin-orbit-entangled pseudospins Jeff =1/2, which have a significant orbital contribution. Therefore, magnetic exchange interactions and anisotropies are highly susceptible to external stimuli such as strain and heterointerface. As a result, it has a significant impact on the magnetic properties of the system. However, …


Global Short-Term Mortality Risk And Burden Associated With Tropical Cyclones From 1980 To 2019: A Multi-Country Time-Series Study, Wenzhong Huang, Shansan Li, Thomas Vogt, Rongbin Xu, Shilu Tong, Tomas Molina, Pierre Masselot, Antonio Gasparrini, Ben Armstrong, Mathilde Pascal, Dominic Roye, Chris Fook Sheng Ng, Ana Maria Vicedo-Cabrera, Joel Schwartz, Eric Lavigne, Haidong Kan, Patrick J. Goodman, Ariana Zeka, Masahiro Hashizume, Magali Hurtado Dias, Cesar De La Cruz Valencia, Xerxes Seposo, Baltazar Nunes, Joana Madureira, Ho Kim, Whanhee Lee, Aurelio Tobias, Carmen Iniguez, Yue Leon Guo, Shih-Chun Pan, Antonella Zanobetti, Tran Ngoc Dang, Do Van Dung, Tobias Geiger, Christian Otto, Amanda Johnson, Simon Hales, Pei Yu, Zhengyu Yang, Elizabeth A. Ritchie, Yuming Guo Jan 2023

Global Short-Term Mortality Risk And Burden Associated With Tropical Cyclones From 1980 To 2019: A Multi-Country Time-Series Study, Wenzhong Huang, Shansan Li, Thomas Vogt, Rongbin Xu, Shilu Tong, Tomas Molina, Pierre Masselot, Antonio Gasparrini, Ben Armstrong, Mathilde Pascal, Dominic Roye, Chris Fook Sheng Ng, Ana Maria Vicedo-Cabrera, Joel Schwartz, Eric Lavigne, Haidong Kan, Patrick J. Goodman, Ariana Zeka, Masahiro Hashizume, Magali Hurtado Dias, Cesar De La Cruz Valencia, Xerxes Seposo, Baltazar Nunes, Joana Madureira, Ho Kim, Whanhee Lee, Aurelio Tobias, Carmen Iniguez, Yue Leon Guo, Shih-Chun Pan, Antonella Zanobetti, Tran Ngoc Dang, Do Van Dung, Tobias Geiger, Christian Otto, Amanda Johnson, Simon Hales, Pei Yu, Zhengyu Yang, Elizabeth A. Ritchie, Yuming Guo

Articles

The global spatiotemporal pattern of mortality risk and burden attributable to tropical cyclones is unclear. We aimed to evaluate the global short-term mortality risk and burden associated with tropical cyclones from 1980 to 2019.


The Effect Of Land-Cover/Land-Use And Habitat Fragmentation On Spatial Patterns Of Lyme Disease In The Eastern United States, Maria Elizabeth Topmiller Jan 2023

The Effect Of Land-Cover/Land-Use And Habitat Fragmentation On Spatial Patterns Of Lyme Disease In The Eastern United States, Maria Elizabeth Topmiller

Theses and Dissertations--Forestry and Natural Resources

Lyme disease has been of national concern for the past few decades. As our understanding of the role of landscape structure in epidemiology expands, it is essential to apply the principles of landscape ecology to the research of vector-borne and zoonotic disease. This study examined the strength of the relationship between land-cover class, degree of habitat fragmentation and county-level Lyme disease cases. Forest, agricultural, and urban land cover types were the categories of interest, while percent cover, edge density, and patch density were the landscape metric used to measure habitat amount and fragmentation. The general linear trends were modelled with …


On The Modelling Of Short And Intermediate Water Waves, Rossen Ivanov Jan 2023

On The Modelling Of Short And Intermediate Water Waves, Rossen Ivanov

Articles

Most of the model equations for water waves are approximations for the long-wave propagation regimes, since most of the energy of the wave motion is concentrated in these waves. Long waves (or shallow-water waves) are defined usually as the depth to wavelength ratio δ = h/λ < 0.05. Several famous integrable nonlinear equations, like the K d V equation [1,2], are models for long waves of small amplitude. The short waves (or waves over deep water) are usually defined with δ > 0.5, and the intermediate waves (or transitional waves) - with 0.05 < δ < 0.5. The intermediate and short waves received a lot less attention, and one reason is perhaps the fact that the corresponding approximations lead to more complicated, nonlinear and nonlocal equations. In [3] an integral equation for surface waves has been proposed for arbitrary wavelengths and finite depth. The problem has been studied in [4] and model equations both for long and short waves are derived from the governing equations as well. The short-wave effects usually compete with the capillarity effects and then resonances can be observed — these have been studied quite a lot, see for example [5–12]. For the intermediate long waves or for waves on deep water the so-called Benjamin–Ono (BO) [13–15] and the Intermediate Long Wave Equation (ILWE) [16–18] are derived for the internal waves below a flat surface, which leads to some simplifications and these models are in fact integrable.


Nonlinear Two-Dimensional Water Waves With Arbitrary Vorticity, Delia Ionescu-Kruse, Rossen Ivanov Jan 2023

Nonlinear Two-Dimensional Water Waves With Arbitrary Vorticity, Delia Ionescu-Kruse, Rossen Ivanov

Articles

We consider the two-dimensional water-wave problem with a general non-zero vorticity field in a fluid volume with a flat bed and a free surface. The nonlinear equations of motion for the chosen surface and volume variables are expressed with the aid of the Dirichlet-Neumann operator and the Green function of the Laplace operator in the fluid domain. Moreover, we provide new explicit expressions for both objects. The field of a point vortex and its interaction with the free surface is studied as an example. In the small-amplitude long-wave Boussinesq and KdV regimes, we obtain appropriate systems of coupled equations for …


Probabilistic Network Analysis Of Social-Ecological Relationships Emerging From Eu Life Projects For Nature And Biodiversity: An Application Of Ergm Models In The Case Study Of The Veneto Region (Italy), Elena Andriollo, Laura Secco, Alberto Caimo, Elena Pisani Jan 2023

Probabilistic Network Analysis Of Social-Ecological Relationships Emerging From Eu Life Projects For Nature And Biodiversity: An Application Of Ergm Models In The Case Study Of The Veneto Region (Italy), Elena Andriollo, Laura Secco, Alberto Caimo, Elena Pisani

Articles

Considering social-ecological relationships in managing protected areas is fundamental to ensuring effective biodiversity conservation and restoration governance. Network analysis offers valuable methods to disentangle intangible relations between and within the social and ecological systems. In this way, it could be possible to identify and integrate multiple social and ecological variables that inevitably affect collaborative environmental governance's effectiveness. Nevertheless, this research area is still nascent, with few methodologies and concrete applications reported in the scientific literature. With this study, we aim to propose a robust novel application of a network methodology to enrich the evaluation of the effectiveness of collaborative environmental …


Turbulence Phenomena In Magnetohydrodynamic Phase Transitions, Giovambattista Amendola, Mauro Fabrizio, John Murrough Golden Jan 2023

Turbulence Phenomena In Magnetohydrodynamic Phase Transitions, Giovambattista Amendola, Mauro Fabrizio, John Murrough Golden

Articles

The model developed in (Fabrizio in J. Eng. Math., 2023) and (Fabrizio in Int. J. Eng. Sci. 44:529–539, 2006), involving the use of a local Reynolds number, is applied to describe phase transitions in a fluid. Specifically, it is applied in a magnetohydrodynamics context to study the evolution of turbulence in certain phenomena. The relevant equations describing the system are those of Navier-Stokes, Ginzburg-Landau and the magnetohydrodynamic equations, all suitably interconnected.


Continual Optimal Adaptive Tracking Of Uncertain Nonlinear Continuous-Time Systems Using Multilayer Neural Networks, Irfan Ganie, S. (Sarangapani) Jagannathan Jan 2023

Continual Optimal Adaptive Tracking Of Uncertain Nonlinear Continuous-Time Systems Using Multilayer Neural Networks, Irfan Ganie, S. (Sarangapani) Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This study provides a lifelong integral reinforcement learning (LIRL)-based optimal tracking scheme for uncertain nonlinear continuous-time (CT) systems using multilayer neural network (MNN). In this LIRL framework, the optimal control policies are generated by using both the critic neural network (NN) weights and single-layer NN identifier. The critic MNN weight tuning is accomplished using an improved singular value decomposition (SVD) of its activation function gradient. The NN identifier, on the other hand, provides the control coefficient matrix for computing the control policies. An online weight velocity attenuation (WVA)-based consolidation scheme is proposed wherein the significance of weights is derived by …


Lifelong Learning Control Of Nonlinear Systems With Constraints Using Multilayer Neural Networks With Application To Mobile Robot Tracking, Irfan Ganie, S. (Sarangapani) Jagannathan Jan 2023

Lifelong Learning Control Of Nonlinear Systems With Constraints Using Multilayer Neural Networks With Application To Mobile Robot Tracking, Irfan Ganie, S. (Sarangapani) Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Presents a Novel Lifelong Multilayer Neural Network (MNN) Tracking Approach for an Uncertain Nonlinear Continuous-Time Strict Feedback System that is Subject to Time-Varying State Constraints. the Proposed Method Uses a Time-Varying Barrier Function to Accommodate the Constraints Leading to the Development of an Efficient Control Scheme. the Unknown Dynamics Are Approximated using a MNN, with Weights Tuned using a Singular Value Decomposition (SVD)-Based Technique. an Online Lifelong Learning (LL) based Elastic Weight Consolidation (EWC) Scheme is Also Incorporated to Alleviate the Issue of Catastrophic Forgetting. the Stability of the overall Closed-Loop System is Analyzed using Lyapunov Analysis. the …


Estimating Evapotranspiration And Analyzing Soil Moisture And Heat Flux Parameters At Taneum Creek, Central Washington, Edward Vlasenko Jan 2023

Estimating Evapotranspiration And Analyzing Soil Moisture And Heat Flux Parameters At Taneum Creek, Central Washington, Edward Vlasenko

All Master's Theses

In the past two decades, stream restoration work, primarily in the form of wood emplacement, has been undertaken in the Taneum Creek watershed, resulting in increased channel-floodplain connectivity. One of the goals of stream restoration was to boost dry season groundwater storage in the shallow floodplain aquifer. However, any gains in groundwater due to increased connectivity may be nullified by increased evapotranspiration (ET) losses because of denser floodplain vegetation. Within the floodplain aquifer budget, ET is a major flow of water out of the system and is not well quantified.

In order to quantify ET, a monitoring site was established …


Forest Management Tradeoffs: Examining Relationships Between Timber Harvest, Carbon Sequestration And Storage, Bioenergy, And Wildlife, Michelle L. Brown Jan 2023

Forest Management Tradeoffs: Examining Relationships Between Timber Harvest, Carbon Sequestration And Storage, Bioenergy, And Wildlife, Michelle L. Brown

Graduate College Dissertations and Theses

Timber harvesting is the leading cause of adult tree mortality in forests of the northeastern United States. While current rates of harvest are generally sustainable, there is considerable pressure to increase harvest to meet timber production, climate, and energy goals. Maximizing one of these values may compromise other forest resources, including a wide range of ecosystem services and the conservation of native species. This dissertation investigates the effects of timber harvest on carbon sequestration and storage, bioenergy, and wildlife. First, I estimated current harvest regimes for different forest types and regions across the U.S. states of New York, Vermont, New …


Paleolimnological Data Synthesis To Assess Long-Term Ecological Change In Vermont Lakes, Ismar Biberovic Jan 2023

Paleolimnological Data Synthesis To Assess Long-Term Ecological Change In Vermont Lakes, Ismar Biberovic

Graduate College Dissertations and Theses

Lakes are excellent early indicators of environmental change on a landscape scale. Due to their connectedness in the landscape, any alteration of land-cover extends beyond a single watershed and can only be amplified by the effects of climate change. These processes can reflect differently across lakes of various characteristics, however, combined, they can leave a lasting impact on biogeochemical processes of a lake, resulting in profound effects on biological communities residing in it. Lake sediments are terrific archives that integrate and preserve this evidence, which then allows us to investigate the extent to which a lake has changed given its …


A Duration-Over-Threshold Model For Flood Frequency And Flow Regime Characterization, Kenneth Scott Feasley Lawson Jan 2023

A Duration-Over-Threshold Model For Flood Frequency And Flow Regime Characterization, Kenneth Scott Feasley Lawson

Graduate College Dissertations and Theses

Proper characterization of river flow is essential for the development of structural and non-structural measures to reduce flood damages, restore ecosystem functions, and manage environmental contaminants in riparian zones. In particular, the duration of flood events is an important feature of floods that drives riverine processes such as erosion, geomorphic adjustment, habitat suitability, nutrient and water quality dynamics, and structural damage. Despite this, most flood characterization methods focus solely on relating the magnitude of annual-maximum discharges to frequency, without addressing the duration of flood events. We investigated event-specific discharge-duration dynamics at 33 USGS stream gages within the US state of …


River Report. State Of Lower St. Johns River Basin, Florida: Water Quality, Fisheries, Aquatic Life, Contaminants, 2023, Environmental Protection Board, Jacksonville Florida, University Of North Florida, Jacksonville University, Gerry Pinto, Brian P. Zoellner, Christopher Baynard, Gretchen Bielmyer-Fraser, Dale Casamatta, Charles Closmann, Nisse Goldberg, Ashley Johnson, Scott Jones, William Penwell, Radha Pyati, Adam Rosenblatt Jan 2023

River Report. State Of Lower St. Johns River Basin, Florida: Water Quality, Fisheries, Aquatic Life, Contaminants, 2023, Environmental Protection Board, Jacksonville Florida, University Of North Florida, Jacksonville University, Gerry Pinto, Brian P. Zoellner, Christopher Baynard, Gretchen Bielmyer-Fraser, Dale Casamatta, Charles Closmann, Nisse Goldberg, Ashley Johnson, Scott Jones, William Penwell, Radha Pyati, Adam Rosenblatt

State of the River Report

No abstract provided.


Post-Translational Modification Of Proteins Via Ambient Air Pollutants And Endogenous Reactive Species, Rachel Lauren Davey Jan 2023

Post-Translational Modification Of Proteins Via Ambient Air Pollutants And Endogenous Reactive Species, Rachel Lauren Davey

Electronic Theses and Dissertations

Proteins can react with reactive oxygen species (ROS) and reactive nitrogen species (RNS) to form post-translational modifications (PTMs), which can affect protein structure and function. The formation of 3-nitrotyrosine (NTyr) and dityrosine (DiTyr) upon reaction of proteins with ROS/RNS are two common PTMs studied due to their stability and irreversibility, as well as their ability to enhance the allergenicity of pollen allergens upon formation. Many common techniques used to study the formation of these PTMs can reliably detect the PTMs but can only provide semi-quantitative information due to many assumptions and limitations. In Chapter 2 we present an analysis of …


Mechanistic Insights Into Mftr-Dependent Regulation Of The Redox Cofactor Mycofactocin, Aigera Mendauletova Jan 2023

Mechanistic Insights Into Mftr-Dependent Regulation Of The Redox Cofactor Mycofactocin, Aigera Mendauletova

Electronic Theses and Dissertations

Organic redox cofactors are essential for life. While classic flavins and nicotinamides are widely distributed across all domains of life, nature has also evolved niche cofactors in subsets of life domains. For example, in Actinobacteria, coenzyme F420 is commonly used in place of flavin mononucleotide in enzymes associated with carbon fixation and oxidation of secondary alcohols. The importance of niche cofactors has long been recognized however, detailed understanding about their biosynthesis and physiological uses has been lagging. One class of niche cofactors is derived from ribosomally synthesized and posttranslationally modified peptides (RiPPs). To achieve their mature form, the genetically …