# Physical Sciences and Mathematics Commons™

Articles 1 - 30 of 1221

## Full-Text Articles in Physical Sciences and Mathematics

Apr 2022

#### Towards A Generalization Of Fulton's Intersection Multiplicity Algorithm, Ryan Sandford

##### Electronic Thesis and Dissertation Repository

In this manuscript we generalize Fulton's bivariate intersection multiplicity algorithm to a partial intersection multiplicity algorithm in the n-variate setting. We extend this generalization of Fulton's algorithm to work at any point, rational or not, using the theory of regular chains. We implement these algorithms in Maple and provide experimental testing. The results indicate the proposed algorithm often outperforms the existing standard basis-free intersection multiplicity algorithm in Maple, typically by one to two orders of magnitude. Moreover, we also provide some examples where the proposed algorithm outperforms intersection multiplicity algorithms which rely on standard bases, indicating the proposed ...

On The Geometry Of Multi-Affine Polynomials, Junquan Xiao Apr 2022

#### On The Geometry Of Multi-Affine Polynomials, Junquan Xiao

##### Electronic Thesis and Dissertation Repository

This work investigates several geometric properties of the solutions of the multi-affine polynomials. Chapters 1, 2 discuss two different notions of invariant circles. Chapter 3 gives several loci of polynomials of degree three. A locus of a complex polynomial p(z) is a minimal, with respect to inclusion, set that contains at least one point of every solution of the polarization of the polynomial. The study of such objects allows one to improve upon know results about the location of zeros and critical points of complex polynomials, see for example [22] and [24]. A complex polynomial has many loci. It ...

Predicting And Modifying Memorability Of Images, Mohammad Younesi Apr 2022

#### Predicting And Modifying Memorability Of Images, Mohammad Younesi

##### Electronic Thesis and Dissertation Repository

Everyday, we are bombarded with many photographs of faces, whether on social media, television, or smartphones. From an evolutionary perspective, faces are intended to be remembered, mainly due to survival and personal relevance. However, all these faces do not have the equal opportunity to stick in our minds. It has been shown that memorability is an intrinsic feature of an image but yet, it is largely unknown what attributes make an image more memorable. In this work, we first proposed new models for predicting memorability of face and object images. Subsequently, we proposed a fast approach to modify and control ...

Investigation Of Sulphide-Poor Gold Mineralization At The Deep A Zone, Kiena Complex, Québec, Stephanie A. Kobylinski Apr 2022

#### Investigation Of Sulphide-Poor Gold Mineralization At The Deep A Zone, Kiena Complex, Québec, Stephanie A. Kobylinski

##### Electronic Thesis and Dissertation Repository

The Kiena Complex is located halfway between Malartic and Val d’Or in Québec, within the Abitibi Greenstone belt in the Superior Province. This study examined mineralization at the Kiena Complex using detailed core logging, geochemical analysis of wall rock, petrography, EPMA, and gold deportment studies. The analysis and interpretations indicate that the unique sulphide-poor gold-rich quartz veins of the Deep A Zone at the Kiena Complex contain 500 μm2) are located at the contact of quartz and corroded albite grains, and fine gold grains (5-500 μm2) are hosted within the corroded albite.

Algorithms For Regular Chains Of Dimension One, Juan P. Gonzalez Trochez Apr 2022

#### Algorithms For Regular Chains Of Dimension One, Juan P. Gonzalez Trochez

##### Electronic Thesis and Dissertation Repository

One of the core commands in the RegularChains library inside Maple is Triangularize. The underlying decomposes the solution set of a polynomial system into geometrically meaningful components represented by regular chains. This algorithm works by repeatedly calling a procedure, called Intersect, which computes the common zeros of a polynomial p and a regular chain T .

As the number of variables of p and T , as well as their degrees, increase, the call to the function Intersect(p, T ) becomes more and more computationally expensive. It was observed in that when the input polynomial system is zero-dimensional and T is one-dimensional ...

Statistical Applications To The Management Of Intensive Care And Step-Down Units, Yawo Mamoua Kobara Apr 2022

#### Statistical Applications To The Management Of Intensive Care And Step-Down Units, Yawo Mamoua Kobara

##### Electronic Thesis and Dissertation Repository

This thesis proposes three contributing manuscripts related to patient flow management, server decision-making, and ventilation time in the intensive care and step-down units system.

First, a Markov decision process (MDP) model with a Monte Carlo simulation was performed to compare two patient flow policies: prioritizing premature step-down and prioritizing rejection of patients when the intensive care unit is congested. The optimal decisions were obtained under the two strategies. The simulation results based on these optimal decisions show that a premature step-down strategy contributes to higher congestion downstream. Counter-intuitively, premature step-down should be discouraged, and patient rejection or divergence actions should ...

A Unified Representation And Deep Learning Architecture For Persuasive Essays In English, Muhammad Tawsif Sazid Apr 2022

#### A Unified Representation And Deep Learning Architecture For Persuasive Essays In English, Muhammad Tawsif Sazid

##### Electronic Thesis and Dissertation Repository

We develop a novel unified representation for the argumentation mining task facilitating the extracting from text and the labelling of the non-argumentative units and argumentation components—premises, claims, and major claims—and the argumentative relations—premise to claim or premise in a support or attack relation, and claim to major claim in a for or against relation—in an end-to-end machine learning pipeline. This tightly integrated representation combines the
component and relation identification sub-problems and enables a unitary solution for detecting argumentation structures. This new representation together with a new deep learning architecture composed of a mixed embedding method, a ...

Apr 2022

#### Plasmonically-Active Nanomaterials For Enhanced Second-Harmonic Generation And Chemical Reactions, Denis Ab Therien

##### Electronic Thesis and Dissertation Repository

Upon excitation by an electromagnetic field, metallic nanomaterials will produce highly localized areas of electromagnetic enhancement, a phenomenon known as localized surface plasmon resonance (LSPR), which can be applied to a variety of techniques including second-harmonic generation (SHG) and surface chemistry. These tunable LSPRs can be modelled prior to fabrication by finite-difference time-domain (FDTD) calculations and observed experimentally by SHG microscopy (SHGM). In this thesis, two types of nanomaterials were characterized using SHGM: plasmon-active dendritic fractals (dendrimers) and transition-metal dichalcogenides (TMDs). Dendrimers with specific geometries and LSPRs were used to demonstrate how nanomaterial symmetry affects SHG as well as how ...

Mar 2022

#### Testing Aftershock Forecasts Using Bayesian Methods, Elisa Dong

##### Electronic Thesis and Dissertation Repository

The presence of strong aftershocks can increase the seismic hazard following a large earthquake and should be considered for operational earthquake forecasting and risk management. Aftershock forecasts are generated from seismicity models during the evolution of the aftershock sequence. This work compares quantitative test results of the forecasting abilities for three competing aftershock rate models - the modified Omori law, the Epidemic Type Aftershock Sequence model, and the compound Omori law - to identify the best performing model for forecasting the largest aftershock during the early aftershock sequence. Forecasts of large aftershock probabilities are generated by either the Extreme Value distribution or ...

The Role Of Transient Vibration Of The Skull On Concussion, Rodrigo Dalvit Carvalho Da Silva Mar 2022

#### The Role Of Transient Vibration Of The Skull On Concussion, Rodrigo Dalvit Carvalho Da Silva

##### Electronic Thesis and Dissertation Repository

Concussion is a traumatic brain injury usually caused by a direct or indirect blow to the head that affects brain function. The maximum mechanical impedance of the brain tissue occurs at 450±50 Hz and may be affected by the skull resonant frequencies. After an impact to the head, vibration resonance of the skull damages the underlying cortex. The skull deforms and vibrates, like a bell for 3 to 5 milliseconds, bruising the cortex. Furthermore, the deceleration forces the frontal and temporal cortex against the skull, eliminating a layer of cerebrospinal fluid. When the skull vibrates, the force spreads directly ...

Feb 2022

#### Physical Investigation Of Downburst Winds And Applicability To Full Scale Events, Federico Canepa

##### Electronic Thesis and Dissertation Repository

Thunderstorm winds, i.e. downbursts, are cold descending currents originating from cumulonimbus clouds which, upon the impingement on the ground, spread radially with high intensities. The downdraft phase of the storm and the subsequent radial outflow that is formed can cause major issues for aviation and immense damages to ground-mounted structures. Thunderstorm winds present characteristics completely different from the stationary Gaussian synoptic winds, which largely affect the mid-latitude areas of the globe in the form of extra-tropical cyclones. Downbursts are very localized winds in both space and time. It follows that their statistical investigation, by means of classical full scale ...

Defining Service Level Agreements In Serverless Computing, Mohamed Elsakhawy Jan 2022

#### Defining Service Level Agreements In Serverless Computing, Mohamed Elsakhawy

##### Electronic Thesis and Dissertation Repository

The emergence of serverless computing has brought significant advancements to the delivery of computing resources to cloud users. With the abstraction of infrastructure, ecosystem, and execution environments, users could focus on their code while relying on the cloud provider to manage the abstracted layers. In addition, desirable features such as autoscaling and high availability became a provider’s responsibility and can be adopted by the user's application at no extra overhead.

Despite such advancements, significant challenges must be overcome as applications transition from monolithic stand-alone deployments to the ephemeral and stateless microservice model of serverless computing. These challenges pertain ...

#### The Effects Of Solution Ph, Temperature And Redox Environment On Corrosion And Oxide Formation On Inconel X-750, Mohsen Bahrami

##### Electronic Thesis and Dissertation Repository

Nickel-based superalloys have a wide range of applications in different industries due to their exceptional mechanical and corrosion-resistance properties. These alloys are widely employed in the nuclear industry. Inside a nuclear reactor, these alloys are exposed to a continuous flux of gamma-radiation. When exposed to gamma-radiation, water decomposes, resulting in the production of oxidizing and reducing species. These species have a considerable effect on the redox chemistry of the solution, which controls the overall corrosion behaviour of nickel-based superalloys.

Corrosion of metals and alloys involves several elementary steps. A comprehensive understanding of these steps and how they influence each other ...

#### Brown Dwarf Atmospheres At High Cadence And Spectral Resolution: A Speed Limit On Brown Dwarf Rotation And A Spectroscopic Atlas Of A 1050 K Atmosphere, Megan E. Tannock

##### Electronic Thesis and Dissertation Repository

Brown dwarfs are sub-stellar objects that form like stars but are not sufficiently massive to sustain hydrogen fusion in their cores. Characterized by cool, molecule-rich atmospheres, brown dwarfs demonstrate great diversity in spectroscopic appearance and share many properties with giant exoplanets. In this thesis I present two investigations: the first is a detailed photometric and spectroscopic study of the three most rapidly rotating brown dwarfs. The second examines a spectrum of a cool brown dwarf at unprecedented spectral resolution and signal-to-noise ratio to study the accuracy of theoretical model photospheres.

Photometric monitoring of brown dwarfs has revealed that periodic variability ...

Equisingular Approximation Of Analytic Germs, Aftab Yusuf Patel Dec 2021

#### Equisingular Approximation Of Analytic Germs, Aftab Yusuf Patel

##### Electronic Thesis and Dissertation Repository

This thesis deals with the problem of approximating germs of real or complex analytic spaces by Nash or algebraic germs. In particular, we investigate the problem of approximating analytic germs in various ways while preserving the Hilbert-Samuel function, which is of importance in the resolution of singularities. We first show that analytic germs that are complete intersections can be arbitrarily closely approximated by algebraic germs which are complete intersections with the same Hilbert-Samuel function. We then show that analytic germs whose local rings are Cohen-Macaulay can be arbitrarily closely approximated by Nash germs whose local rings are Cohen- Macaulay and ...

#### In Situ Study Of Geological Fluid Inclusions Using 23na Nuclear Magnetic Resonance Spectroscopy, Stephen Pilar

##### Electronic Thesis and Dissertation Repository

23Na Magic Angle Spinning Solid State Nuclear Magnetic Resonance (MAS SS NMR) spectroscopy has been used to study natural geological samples of halite, fluorite, and quartz to evaluate the efficacy of NMR spectroscopy for in situ fluid inclusion analysis. NaCl calibration standards yielded a strong linear correlation (R2=0.9919) for salinity, albeit only over a ~1 ppm breadth of chemical shift. Fluid inclusions were successfully identified in all three types of minerals studied using MAS NMR. Chemical analysis with Inductively Coupled Plasma -- Mass Spectrometry (ICP-MS) was employed to quantify elemental contaminants in halite samples. Powder X-Ray Diffraction ...

#### Effects Of Gamma-Radiation On The Evolution Of Copper Corrosion Dynamics In Deep Geological Repository Solution Environments, Lindsay J. Grandy

##### Electronic Thesis and Dissertation Repository

The Canadian plan for permanent disposal of used nuclear fuel involves a used fuel container (UFC), a carbon steel vessel with a copper coating to provide the corrosion protection. The corrosion conditions for the copper layer of the UFC are expected to involve small, stagnant water volumes, pH values between 6 and 9, and a continuous flux of γ-radiation emitted from the radionuclides trapped in the fuel matrix. While γ-radiation does not affect the copper metal directly, humid air and water will radiolytically decompose into redox-active and acidic species which will be produced at constant concentrations and can alter the ...

Oct 2021

#### Cache-Friendly, Modular And Parallel Schemes For Computing Subresultant Chains, Mohammadali Asadi

##### Electronic Thesis and Dissertation Repository

The RegularChains library in Maple offers a collection of commands for solving polynomial systems symbolically with taking advantage of the theory of regular chains. The primary goal of this thesis is algorithmic contributions, in particular, to high-performance computational schemes for subresultant chains and underlying routines to extend that of RegularChains in a C/C++ open-source library.

Subresultants are one of the most fundamental tools in computer algebra. They are at the core of numerous algorithms including, but not limited to, polynomial GCD computations, polynomial system solving, and symbolic integration. When the subresultant chain of two polynomials is involved in a ...

#### Structural Tuning And Spectroscopic Characterizations Of Polysulfide As Battery Materials, Daiqiang Liu

##### Electronic Thesis and Dissertation Repository

Polysulfide materials have drawn extensive attention for next-generation battery development since the current lithium-ion battery has almost reached its limit regarding energy density and safety issues. Many phosphorus and sodium sulfide materials have been used in different battery types, such as solid-state and sodium-sulfur batteries. However, there are still issues that prevent these techniques from applications. In recent years, there has been increasing attention on investigations of the structural and phase transformations of electrode and electrolyte materials under high pressure. Many studies have shown that external pressure can affect structural properties and influence electrical properties. In this study, three battery-related ...

Evolutionary Design Of Search And Triage Interfaces For Large Document Sets, Jonathan A. Demelo Oct 2021

#### Evolutionary Design Of Search And Triage Interfaces For Large Document Sets, Jonathan A. Demelo

##### Electronic Thesis and Dissertation Repository

This dissertation is concerned with the design of visual interfaces for searching and triaging large document sets. Data proliferation has generated new and challenging information-based tasks across various domains. Yet, as the document sets of these tasks grow, it has become increasingly difficult for users to remain active participants in the information-seeking process, such as when searching and triaging large document sets. During information search, users seek to understand their document set, align domain knowledge, formulate effective queries, and use those queries to develop document set mappings which help generate encounters with valued documents. During information triage, users encounter the ...

Oct 2021

#### Compound Sums, Their Distributions, And Actuarial Pricing, Ang Li

##### Electronic Thesis and Dissertation Repository

Compound risk models are widely used in insurance companies to mathematically describe their aggregate amount of losses during certain time period. However, evaluation of the distribution of compound random variables and the computation of the relevant risk measures are non-trivial. Therefore, the main purpose of this thesis is to study the bounds and simulation methods for both univariate and multivariate compound distributions. The premium setting principles related to dependent multivariate compound distributions are studied. .

In the first part of this thesis, we consider the upper and lower bounds of the tail of bivariate compound distributions. Our results extend those in ...

Non-Circular Hydraulic Jumps Due To Inclined Jets, Ahmed Mohamed Abdelaziz Oct 2021

#### Non-Circular Hydraulic Jumps Due To Inclined Jets, Ahmed Mohamed Abdelaziz

##### Electronic Thesis and Dissertation Repository

When a laminar inclined circular jet impinges on a horizontal surface, it forms a non-circular hydraulic jump governed by a non-axisymmetric flow. In this thesis, we use the boundary-layer and thin-film approaches in the three dimensions to theoretically analyse such flow and the hydraulic jumps produced in such cases. We particularly explore the interplay among inertia, gravity, and the effective inclination angle on the non-axisymmetric flow.

The boundary-layer height is found to show an azimuthal dependence at strong gravity level only; however, the thin film thickness as well as the hydraulic jump profile showed a strong non-axisymmetric behaviour at all ...

Distribution Of The P-Torsion Of Jacobian Groups Of Regular Matroids, Sergio R. Zapata Ceballos Oct 2021

#### Distribution Of The P-Torsion Of Jacobian Groups Of Regular Matroids, Sergio R. Zapata Ceballos

##### Electronic Thesis and Dissertation Repository

Given a regular matroid $M$ and a map $\lambda\colon E(M)\to \N$, we construct a regular matroid $M_\lambda$. Then we study the distribution of the $p$-torsion of the Jacobian groups of the family $\{M_\lambda\}_{\lambda\in\N^{E(M)}}$. We approach the problem by parameterizing the Jacobian groups of this family with non-trivial $p$-torsion by the $\F_p$-rational points of the configuration hypersurface associated to $M$. In this way, we reduce the problem to counting points over finite fields. As a result, we obtain a closed formula for the proportion of these groups ...

#### Evaluating Cranial Nonmetric Traits In Mummies From Pachacamac, Peru: The Utility Of Semi-Automated Image Segmentation In Paleoradiology, Cameron J. Beason

##### Electronic Thesis and Dissertation Repository

Anthropologists employ biodistance analysis to understand past population interactions and relatedness. The objectives of this thesis are twofold: to determine whether a sample of five mummies from the pilgrimage centre, Pachacamac, on the Central Coast of Peru comprised local or non-local individuals through an analysis of cranial nonmetric traits using comparative samples from the North and Central Coasts of Peru and Chile; and to test the utility of machine-learning-based image segmentation in the image analysis software, Dragonfly, to automatically segment CT scans of the mummies such that the cranial nonmetric traits are visible. Results show that while fully automated segmentation ...

Sep 2021

#### Characterization Of Extracellular Vesicles By Surface-Enhanced Raman Spectroscopy, Nina M. Culum

##### Electronic Thesis and Dissertation Repository

Extracellular vesicles (EVs), which are nanoscale vesicles secreted by cells into biofluids, are of research interest due to their roles in intercellular communication. EVs released from mesenchymal stromal cells (MSCs) have tremendous potential in cell-free regenerative medicine, while EVs released from diseased cells are being studied as biomarkers for minimally invasive and early disease detection. Presented in this thesis are gold nanohole arrays for the capture and sensitive detection of EVs by surface-enhanced Raman spectroscopy (SERS), a plasmonic technique capable of single molecule detection. Herein, we have characterized EVs released from MSCs and ovarian cancer cells, with a focus on ...

#### Functional Nanoparticles: Tin Monoxide And Molybdenum Disulfide Quantum Dots On Graphene Nanosheets, Denys Vidish

##### Electronic Thesis and Dissertation Repository

Light harvesting can be referred to the use of an ensemble of different nanoparticles, or quantum dots, or other absorbers to optimize the ability to capture a given spectrum of electromagnetic radiation (for example the solar spectrum under specific atmospheric conditions) in a light-absorbing system. To this end, different nanoparticles play complementary functions within the system and absorb or scatter light at different wavelength intervals. Light harvesting finds applications in fields as diverse as solar cells, photosynthesis and photocatalysis. Graphene supporting a set of different semiconducting nanoparticles has often been proposed as light harvesters. To further this concept, my thesis ...

Aug 2021

#### Revisiting Polycyclic Aromatic Hydrocarbon Emission In Photodissociation Regions, Ameek K. Sidhu

##### Electronic Thesis and Dissertation Repository

The mid-infrared (IR) spectrum of almost all objects in the Universe is dominated by a set of strong emission features characteristic of a class of large organic molecules made of carbon and hydrogen known as polycyclic aromatic hydrocarbons (PAHs). These molecules account for ~15% of the cosmic carbon and ~20% of the total IR power of the Milky Way and star-forming galaxies. They are strong absorbers of ultraviolet (UV) photons and release the absorbed energy through vibrational transitions that result in strong IR emission features. PAHs play a critical role in the evolution of the interstellar medium (ISM) as they ...

Genus Bounds For Some Dynatomic Modular Curves, Andrew W. Herring Aug 2021

#### Genus Bounds For Some Dynatomic Modular Curves, Andrew W. Herring

##### Electronic Thesis and Dissertation Repository

We prove that for every $n \ge 10$ there are at most finitely many values $c \in \mathbb{Q}$ such that the quadratic polynomial $x^2 + c$ has a point $\alpha \in \mathbb{Q}$ of period $n$. We achieve this by proving that for these values of $n$, every $n$-th dynatomic modular curve has genus at least two.

A Generative-Discriminative Approach To Human Brain Mapping, Deepanshu Wadhwa Aug 2021

#### A Generative-Discriminative Approach To Human Brain Mapping, Deepanshu Wadhwa

##### Electronic Thesis and Dissertation Repository

During everyday behaviours, the brain shows complex spatial patterns of activity. These activity maps are very replicable within an individual, but vary significantly across individuals, even though they are evoked by the same behaviour. It is unknown how differences in these spatial patterns relate to differences in behavior or function. More fundamentally, the structural, developmental, and genetic factors that determine the spatial organisation of these brain maps in each individual are unclear. Here we propose a new quantitative approach for uncovering the basic principles by which functional brain maps are organized. We propose to take an generative-discriminative approach to human ...

Aug 2021

#### Coevolution Of Hosts And Pathogens In The Presence Of Multiple Types Of Hosts, Evan J. Mitchell

##### Electronic Thesis and Dissertation Repository

How will hosts and pathogens coevolve in response to multiple types of hosts? I study this question from three different perspectives. First, I model a scenario in which hosts are categorized as female or male. Hosts invest resources in maintaining their immune system at a cost to their reproductive success, while pathogens face a trade-off between transmission and duration of infection. Importantly, female hosts are also able to vertically transmit an infection to their newborn offspring. The main result is that as the rate of vertical transmission increases, female hosts will have a greater incentive to pay the cost to ...