Physical Sciences and Mathematics Commons^™

Mathematical Modeling And Simulation Of Biologically Inspired Hair Receptor Arrays In Laminar Unsteady Flow Separation, John R. Singler, Belinda A. Batten, Benjamin T. Dickinson

Mathematics and Statistics Faculty Research & Creative Works

Bats possess arrays of distributed flow-sensitive hair-like mechanoreceptors on their dorsal and ventral wing surfaces. Bat wing hair receptors are known to play a significant role in flight maneuverability and are directionally most sensitive to reversed flow over the wing. in this work, we consider the mechanics of flexible hair-like structures for the time accurate detection and visualization of hydrodynamic images associated with unsteady near surface flow phenomena. a nonlinear viscoelastic model of a hair-like structure coupled to an unsteady nonuniform flow is proposed. Writing the hair model in nondimensional form, we identify five dimensionless groups that govern hair behavior. …

A Linear Energy Stable Scheme For A Thin Film Model Without Slope Selection, Wenbin Chen, Sidafa Conde, Cheng Wang, Xiaoming Wang, Steven M. Wise

Mathematics and Statistics Faculty Research & Creative Works

We present a linear numerical scheme for a model of epitaxial thin film growth without slope selection. the PDE, which is a nonlinear, fourth-order parabolic equation, is the L2 gradient flow of the energy ∫Ω(-1/2 ln(1 + |ø|2) + ε2 2 |Ø(x)|2) dx. the idea of convex-concave decomposition of the energy functional is applied, which results in a numerical scheme that is unconditionally energy stable, i.e., energy dissipative. the particular decomposition used here places the nonlinear term in the concave part of the energy, in contrast to a previous convexity splitting scheme. as a result, the numerical scheme is fully …

Productivity Formulae Of An Infinite-Conductivity Hydraulically Fractured Well Producing At Constant Wellbore Pressure Based On Numerical Solutions Of A Weakly Singular Integral Equation Of The First Kind, Chaolang Hu, Jing Lu, Xiaoming He

Mathematics and Statistics Faculty Research & Creative Works

In order to increase productivity, it is important to study the performance of a hydraulically fractured well producing at constant wellbore pressure. This paper constructs a new productivity formula, which is obtained by solving a weakly singular integral equation of the first kind, for an infinite-conductivity hydraulically fractured well producing at constant pressure. And the two key components of this paper are a weakly singular integral equation of the first kind and a steady-state productivity formula. A new midrectangle algorithm and a Galerkin method are presented in order to solve the weakly singular integral equation. The numerical results of these …

Almost Oscillatory Three Dimensional Dynamic Systems, Elvan Akin, Zuzana Dosla, Bonita Lawrence

Mathematics and Statistics Faculty Research & Creative Works

In this article, we investigate oscillation and asymptotic properties for 3D systems of dynamic equations. We show the role of nonlinearities and we apply our results to the adjoint dynamic systems.

Absolute Differentiation In Metric Spaces, W. J. Charatonik, Matt Insall

Mathematics and Statistics Faculty Research & Creative Works

In this article, we introduce a new notion of (strong) absolute derivative, for functions derived between metric spaces, and we investigate various properties and uses of this concept, especially regarding the geometry of abstract metric spaces carrying no other structure.

Intensity Dependence Of Multiple Orbital Contributions And Shape Resonance In High-Order Harmonic Generation Of Aligned N₂ Molecules, Cheng Jin, Julien B. Bertrand, R. R. Lucchese, H .J. Worner, Paul B. Corkum, D. M. Villeneuve, Anh-Thu Le, C. D. Lin

Physics Faculty Research & Creative Works

We report measurements and theoretical simulations of high-order harmonic generation (HHG) in aligned N₂ molecules using a 1200-nm intense laser field when the generating pulse is perpendicular to the aligning one. With increasing laser intensity, the minimum in the HHG spectra first shifts its position and then disappears. Theoretical simulations including the macroscopic propagation effects in the medium reproduce these observations and the disappearance of the minimum is attributed to the additional contribution of HHG from inner orbitals. We also predict that the well-known shape resonance in the photoionization spectra of N₂ should exist in the HHG spectra. It is …

Separation And Liquid Chromatography Using A Single Carbon Nanotube, Riju Singhal, Vadym Mochalin, Maria R. Lukatskaya, Gary Friedman, Yury G. Gogotsi

Chemistry Faculty Research & Creative Works

Use of a single template-grown carbon nanotube as a separation column to separate attoliter volumes of binary mixtures of fluorescent dyes has been demonstrated. The cylindrical nanotube walls are used as stationary phase and the surface area is increased by growing smaller multi-walled carbon nanotubes within the larger nanotube column. Liquid-liquid extraction is performed to separate selectively soluble solutes in a solvent, and chromatographic separation is demonstrated using thin, long nanotubes coated inside with iron oxide nanoparticles. The setup is also used to determine the diffusion coefficient of a solute at the sub-micrometer scale. This study opens avenues for analytical …

Neutron Repulsion, Oliver Manuel

Chemistry Faculty Research & Creative Works

Earth is connected gravitationally, magnetically and electrically to its heat source and the source of its chemical elements - a neutron star obscured from view by waste products in the photosphere. Neutron repulsion makes the solar core like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the pulsar, decay to hydrogen, and partially fuse into the helium now trapped with it in the photosphere, like a frosted light bulb. Neutron repulsion is the overlooked source of energy, the keystone of an arch that locks together many earlier, puzzling observations: 1.) Excess ¹³⁶Xe accompanied primordial …

Histological Evaluation Of The Biocompatibility Of Polyurea Crosslinked Silica Aerogel Implants In A Rat Model: A Pilot Study, Firouzeh Sabri, J. D. Boughter Jr., D. Gerth, O. Skalli, T. C. N. Phung, G. R. M. Tamula, Nicholas Leventis

Chemistry Faculty Research & Creative Works

Background: Aerogels are a versatile group of nanostructured/nanoporous materials with physical and chemical properties that can be adjusted to suit the application of interest. In terms of biomedical applications, aerogels are particularly suitable for implants such as membranes, tissue growth scaffolds, and nerve regeneration and guidance inserts. The mesoporous nature of aerogels can also be used for diffusion based release of drugs that are loaded during the drying stage of the material. From the variety of aerogels polyurea crosslinked silica aerogels have the most potential for future biomedical applications and are explored here. Methodology: This study assessed the short and …

N-Acetyl-L-Cysteine Amide Protects Retinal Pigment Epithelium Against Methamphetamine-Induced Oxidative Stress, Nuran Ercal, Joshua W. Carey, Shakila Tobwala, Xinsheng Zhang, Atrayee Banerjee, Eylem Y. Pinarci, Humeyra Karacal

Chemistry Faculty Research & Creative Works

Methamphetamine (METH), a highly addictive drug used worldwide, induces oxidative stress in various animal organs. Recent animal studies indicate that methamphetamine also induces oxidative stress in the retina, which is an em- bryonic extension of the forebrain. The aim of this study, therefore, was to evaluate the pro- tecttive effects of N-acetylcysteine amide (NACA) against oxidative stress induced by METH in retinal pigment epithelium (RPE) cells. Our stud- ies showed that NACA protected against METH- induced oxidative stress in retinal pigment epithelial cells. Although METH significantly de- creased glutathione (GSH) levels and increased reactive oxygen species (ROS) and malondial- dehyde …

Semantic Preserving Text Tepresentation And Its Applications In Text Clustering, Michael Howard

Masters Theses

Text mining using the vector space representation has proven to be an valuable tool for classification, prediction, information retrieval and extraction. The nature of text data presents several issues to these tasks, including large dimension and the existence of special polysemous and synonymous words. A variety of techniques have been devised to overcome these shortcomings, including feature selection and word sense disambiguation. Privacy preserving data mining is also an area of emerging interest. Existing techniques for privacy preserving data mining require the use of secure computation protocols, which often incur a greatly increased computational cost. In this paper, a generalization-based …

Comparison Of Experiment And Theory For Electron Impact Ionization Of Isoelectronic Atoms And Molecules, Hari Chaluvadi, Kate L. Nixon, Sadek M. Amami, Andrew James Murray, Don H. Madison

Physics Faculty Research & Creative Works

Experimental and Theoretical Triply Differential Cross sections will be presented for low energy electron impact ionization of Ne, CH₄, and NH₃. The collision mechanisms responsible for the various structures found in the cross sections will be discussed.

Physiochemical Characteristics Contributing To The Cytotoxicity Of Transition Metal Oxides, Chi-Heng Wu

Masters Theses

"In the past ten years nanotechnology has not only evolved to play a prominent role in our economy but also increased the concern over potential adverse effects caused by nanomaterials to human health and the environment. Nanotoxicity is to understand the nature and origin of the toxicity imposed by nanomaterials. Studies from our laboratory have shown that nanoparticle induces oxidative stress, perturbs calcium homeostasis, alter gene expression, and produces pro-inflammatory responses. We also identified a trend of toxicity: TiO₂ < Cr₂O₃ < Fe₂O₃ < Mn₂O₃ < NiO < ZnO < CuO. We then asked a question: what are physiochemical factors of transition metal nanoparticles that contributed to this increasing cytotoxicity. In this thesis I investigated the correlation between physicochemical properties and toxicity of the transition metal oxides in the 4th Period of the Periodic Table of Elements. Particle size, BET surface area, point of zero charge, metal dissolution, and degree of surface adsorption of transition metal oxide nanoparticles were measured. There were no increasing trends in both particle size and specific surface area. The point of zero charge showed an increasing trend as TiO₂ < Cr₂O₃ < Fe₂O₃ < NiO < CuO = ZnO < Mn₂O₃. The number of available binding sites of nanoparticle showed an increasing trend as Cr₂O₃ > ZnO > CuO > NiO > Fe₂O₃ > Mn₂O₃ > TiO₂. The degree of adsorption on the surface of nanoparticles showed an increasing trend with atomic …

Stability Of Rock Slopes Along Raidah Escarpment Road, Asir Area, Kingdom Of Saudi Arabia, Ahmed M. Youssef, Norbert H. Maerz, Abdulla A. Al-Otaibi

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Raidah Escarpment road is located north west of Abha city, Asir region, Kingdom of Saudi Arabia. This escarpment road represents an important corridor in the area which connects different villages and tourist resorts with each other. The total length of this road section is about 9 km which passes through a highly mountainous area. The road also passes through areas of different geological hazards (rock, debris flow, soil, and weathered zones). The different environmental factors (e.g. intensive rainy summer), variable geological and structural elements (weak rocks, slide debris weak soils, shear zones, and faults) difficult road characteristics (narrow roads …

Strongly Enhanced Backward Emission Of Electrons In Transfer And Ionization, Michael Schulz, Xincheng Wang, M. Gundmundsson, Katharina R. Schneider, Aditya H. Kelkar, Alexander B. Voitkiv, B. Najjari, Markus S. Schoffler, Lothar Ph H H Schmidt, Reinhard Dorner, Joachim Hermann Ullrich, Robert Moshammer, Daniel Fischer

Physics Faculty Research & Creative Works

We studied three-dimensional angular distributions and longitudinal momentum spectra of electrons ejected in transfer plus ionization (TI), i.e., the ejection of one and the capture of a second target electron, for ion-helium collisions. We observe a pronounced structure strongly focused opposite to the projectile beam direction, which we associate with a new correlated TI mechanism proposed recently. This process contributes significantly to the total cross sections over a broad range of perturbations η, even at η as large as 0.5, where uncorrelated TI mechanisms were thought to be dominant.

Effect Of Projectile Coherence On Atomic Fragmentation Processes, Michael Schulz, Kisra N. Egodapitiya, Sachin D. Sharma, Aaron C. Laforge, Robert Moshammer, A. A. Hasan, Don H. Madison

Physics Faculty Research & Creative Works

We demonstrate that the projectile coherence can have a major impact on atomic fragmentation processes. This has been overlooked for decades in formal scattering theory and may explain puzzling discrepancies between theoretical and experimental fully differential cross sections for single ionization.

Investigation Of Polyurea-Crosslinked Silica Aerogels As A Neuronal Scaffold: A Pilot Study, Firouzeh Sabri, Judith A. Cole, M. Cody Scarbrough, Nicholas Leventis

Chemistry Faculty Research & Creative Works

Background: Polymer crosslinked aerogels are an attractive class of materials for future implant applications particularly as a biomaterial for the support of nerve growth. The low density and nano-porous structure of this material combined with large surface area, high mechanical strength, and tunable surface properties, make aerogels materials with a high potential in aiding repair of injuries of the peripheral nervous system. However, the interaction of neurons with aerogels remains to be investigated. Methodology: In this work the attachment and growth of neurons on clear polyurea crosslinked silica aerogels (PCSA) coated with: poly-L-lysine, basement membrane extract (BME), and laminin1 was …

Experimental And Theoretical Investigation Of The Triple Differential Cross Section For Electron Impact Ionization Of Pyrimidine Molecules, J. D. Builth-Williams, Susan M. Bellm, Darryl B. Jones, Hari Chaluvadi, Don H. Madison, Chuangang Ning, B. Lohmann, Michael J. Brunger

Physics Faculty Research & Creative Works

Cross-section data for electron impact induced ionization of bio-molecules are important for modelling the deposition of energy within a biological medium and for gaining knowledge of electron driven processes at the molecular level. Triply differential cross sections have been measured for the electron impact ionization of the outer valence 7b ₂ and 10a ₁ orbitals of pyrimidine, using the (e, 2e) technique. The measurements have been performed with coplanar asymmetric kinematics, at an incident electron energy of 250 eV and ejected electron energy of 20 eV, for scattered electron angles of -5°, -10°, and -15°. The ejected electron angular range …

Differential Cross Sections For Single Ionization Of H₂ By 75kev Proton Impact, Ujjal Chowdhury, Michael Schulz, Don H. Madison

Physics Faculty Research & Creative Works

We have calculated Triply differential cross sections (TDCS) and doubly differential cross sections (DDCS) for single ionization of H₂ by 75 keV proton impact using the molecular 3 body distorted wave Eikonal initial state (M3DW-EIS) approach. Previously published measured DDCS-P (differential in the projectile scattering angle and integrated over the ejected electron angles) found pronounced structures at relatively large angles which were interpreted as an interference resulting from the two-centered potential of the molecule.

How Should Plastic-Packaging Companies Apply Artificial Proofs And Topics Of Invention To Communicate Sustainability? : A Heuristic Developed On The Basis Of Rhetorical Analysis, Shristy Bashyal

Masters Theses

"This study examines how the ten plastic-packaging companies use artificial proofs and topics of invention to communicate sustainability-related information. The objective of this study was to answer the following research questions:

(i) Do plastic-packaging companies define sustainability on their website?

(ii) What are the strengths and weaknesses of the arguments in these companies' sustainability-related communications?

(iii) What invention strategies should technical marketing communicators use to communicate company's sustainable practices?

To answer these questions, I analyzed the sustainability-related documents available on the websites of the ten companies. On the basis of this analysis, I developed an invention heuristic that can be …

Electrodeposition And Electrochemical Reduction Of Epitaxial Metal Oxide Thin Films And Superlattices, Zhen He

Doctoral Dissertations

"The focus of this dissertation is the electrodeposition and electrochemical reduction of epitaxial metal oxide thin films and superlattices. The electrochemical reduction of metal oxides to metals has been studied for decades as an alternative to pyrometallurgical processes for the metallurgy industry. However, the previous work was conducted on bulk polycrystalline metal oxides. Paper I in this dissertation shows that epitaxial face-centered cubic magnetite (Fe₃O₄) thin films can be electrochemically reduced to epitaxial body-centered cubic iron (Fe) thin films in aqueous solution on single-crystalline Au substrates at room temperature. This technique opens new possibilities to produce special epitaxial metal/metal oxide …

Abel Dynamic Equations Of The First And Second Kind, Sabrina Heike Streipert

Masters Theses

"In this work, we study Abel dynamic equations of the first and the second kind. After a brief introduction to time scales, we introduce the Abel differential equations of the first and the second kind, as well as the canonical Abel form in the continuous case. Using the existing information, we derive novel results for time scales. We provide formulas for the Abel dynamic equations of the second kind and present a solution method. We furthermore achieve a special class of Abel equations of the first kind and discuss the canonical Abel equation. We get relations between common dynamic equations …

Depositional And Tectonic Controls On Architecture Of The Carbonate Platform Of Upper Paleocene Khalifah Formation, Sirte Basin, Central Libya, Salah Abdurzak Shaniba

Masters Theses

"The Paleocene strata in Sirte Basin, Libya, contain major oil and gas accumulations in a variety of lithofacies of reef and bioherm carbonate depositional environments. The Upper Paleocene Khalifah Formation, which is one of the main reservoirs containing about 30% of the oil reserves of the Sirte Basin, is composed of shallowing-upward and carbonate platform deposits and is capped by open marine shale deposits formed during a marine transgression. Well and seismic data are used to interpret the depositional environments and identify upward shallowing and deepening trends in the formation. In the study area, Mabruk oil field in northwestern Sirte …

All-Sky Search For Periodic Gravitational Waves In The Full S5 Ligo Data, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report on an all-sky search for periodic gravitational waves in the frequency band 50-800Hz and with the frequency time derivative in the range of 0 through -6 x 10^-9Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. After recent improvements in the search program that yielded a 10x increase in computational efficiency, we have searched in two years of data collected during LIGO's fifth science run and have obtained the most sensitive all-sky upper limits on gravitational-wave strain to date. Near 150Hz our upper limit on …

Investigation Of Biomarkers For Noninvasive Early Diagnosis Of Cancer, Sanjeewa Bandara Gamagedara

Doctoral Dissertations

"Cancer is the second leading cause of death worldwide, and deaths from cancer worldwide are projected to continue rising, with an estimated 12 million deaths in 2030. Cancer occurs when cells in a part of the body begin to grow out of control. It develops very rapidly, and early diagnosis offers a greater chance of successful treatment and a higher survival rate. Biomarkers are good potential tools for early diagnosis. The main hypothesis of this study is that the levels of certain metabolites present in human urine can indicate the current or future behavior of cancer. Therefore, these studies focused …

Part I: Quantitative Determination Of Total Corrosive Sulfur In Mineral Insulating Oils And Technical Liquids; Part Ii: Development And Validation Of A Broad Spectrum Microbial Disinfectant, Kyle Rodney Anderson

Doctoral Dissertations

"Part one of this dissertation deals with the development and validation of a test method for determination of total corrosive sulfur in mineral insulating oils other technical oils. The method involved reaction of corrosive sulfur compounds in oils with finely divided copper at temperatures ≥ 110 °C. The reaction yielded cuprous sulfide (Cu₂S), Cu₂S was then oxidized to cupric sulfate (CuSO₄), which was determined as sulfate with ion chromatography. The method offers a quantitative assessment of corrosive sulfur compounds in oils and eliminates ambiguities associated with the international standard methods for corrosive sulfur in mineral insulating oils and other technical …

Therapeutic Effects Of N-Acetylcysteine Amide In The Treatment Of Eye Disorders, Joshua W. Carey

Doctoral Dissertations

"The loss of vision from age-related eye diseases now affects over 30 million people in the United States and is expected to reach twice that number within the next couple of decades. Among these disorders, age-related macular degeneration and cataract formation represent the largest percentage of these cases. Therapeutic options available for treating age-related macular degeneration are limited and there is no noninvasive form of treatment for cataracts current available. Several studies have indicated that oxidative stress plays an important role in the pathology of these age-related eye disorders. If oxidative stress is responsible for the initiation and progression of …

Handel's Maser-Solution Theory Of Ball Lightning: The Creation Of Stable Three-Dimensional Cavitons By An Atmospheric Maser With An Open Resonator, Glenn Andrew Carlson

Doctoral Dissertations

"This dissertation develops details of Handel's Maser-Soliton Theory of ball lightning. The atmosphere between a thundercloud and the Earth's surface is modeled as an idealized stable open resonator with water vapor as the active medium and the thundercloud and Earth's surface as reflecting surfaces. The stable resonator generates a maser beam that narrows to the beam waist at the Earth's surface, which is assumed to be planar. Two candidate rotational transitions are identified within the v₁v₂v₃ = 010 vibrational band of water having wavelengths of 13.9 cm and 1.12 cm, and relevant spectroscopic parameters are retrieved from the HITRAN 2008 …

Small Sample Inference For Exponential Survival Times With Heavy Right-Censoring, Noroharivelo Volaniaina Randrianampy

Doctoral Dissertations

"We develop a saddlepoint-based method and several generalized Bartholomew methods for generating confidence intervals about the rate parameter of an exponential distribution in the presence of heavy random right-censoring. Butler's conditional moment generating function formula is used to derive the relevant moment generating function for the rate parameter score function which provides access to a saddlepoint-based bootstrap method. Moment generating functions also play a key role in the generalized Bartholomew methods we develop. Since heavy censoring is assumed, the possible non-existence of the rate parameter maximum likelihood estimate (MLE) is nonignorable. The overwhelming majority of existing methods condition upon the …

Theoretical Studies Of Few-Body Problems, Uttam Chowdhury

Doctoral Dissertations

"Heavy ion collisions with atomic and molecular targets produce many outcomes. The Schrödinger equation is not analytically soluble for more than two mutually interacting particles. As a result, theory must resort to using approximations, the validity of which is determined by comparison with experiment. This work is focused on finding better approximations to describe ionization and capture processes in proton collisions.

Proton-impact ionization of molecular hydrogen is treated as a 3-body problem. Usually the target is treated as an atomic target and the results are multiplied by an ad hoc factor to account for the molecular structure. Measured cross sections …