Digital Commons Network^™

Approximations And Bounds For Optimal Controls Via Finite Fourier Series, Gabriel Nicolosi, Terry Friesz, Christopher Griffin

Engineering Management and Systems Engineering Faculty Research & Creative Works

This work considers the problem of approximating initial condition and time-dependent optimal control and trajectory surfaces using multivariable finite Fourier series. A modified Augmented Lagrangian algorithm for translating the optimal control problem into an unconstrained optimization one is proposed. A quadratic control problem in the context of Newtonian mechanics is solved to demonstrate the proposed algorithm and various computational results are presented. Use of automatic differentiation is explored to circumvent the elaborated gradient computation in the first-order optimization procedure. Furthermore, mean square error bounds are derived for the case of one and two-dimensional Fourier series approximations, suggesting a general bound …

Quality Assurance Framework For Recovered Binders And Aggregates From Asphalt Mixtures Incorporating Recycled Materials, Eslam Deef-Allah, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study proposes that a proactive quality assurance (QA) framework for asphalt mixes with recycled materials, i.e., reclaimed asphalt pavement and recycled asphalt shingles, should be developed. Quality control (QC) is generally concerned with the contractor's obligation to produce mixes which meet the job mix formula (JMF) targets. However, QA considers the variability in fabrication processes and materials and offers monitoring by evaluating the contractor's performance. Although both aggregate gradations and asphalt contents were within the JMF specifications, the recovered binders revealed significant differences from the contract binders in the JMF. Rheological tests indicated increased stiffness and elasticity but reduced …

Interferometric Differential High-Frequency Lock-In Probe For Laser-Induced Vacuum Birefringence, R. G. Bullis, Ulrich D. Jentschura, D. C. Yost

Physics Faculty Research & Creative Works

We propose a measurement of laser-induced vacuum birefringence through the use of pulsed lasers coupled to femtosecond optical enhancement cavities. This measurement technique features cavity-enhanced pump and probe pulses, as well as an independent control pulse. The control pulse allows for a differential measurement where the final signal is obtained using high-frequency lock-in detection, greatly mitigating time-dependent cavity birefringence as an important and possibly prohibitive systematic effect. In addition, the method features the economical use of laser power and results in a relatively simple experimental setup.

Phases And Dynamics Of Quantum Droplets In The Crossover To Two-Dimensions, Jose Carlos Pelayo, George Bougas, Thomás Fogarty, Thomas Busch, Simeon I. Mistakidis

Physics Faculty Research & Creative Works

We explore the ground states and dynamics of ultracold atomic droplets in the crossover region from three to two dimensions by solving the two-dimensional and the quasi-two-dimensional extended Gross-Pitaevskii equations numerically and with a variational approach. By systematically comparing the droplet properties, we determine the validity regions of the pure two-dimensional description, and therefore the dominance of the logarithmic nonlinear coupling, as a function of the sign of the averaged mean-field interactions and the size of the transverse confinement. One of our main findings is that droplets become substantially extended upon transitioning from negative-to-positive averaged mean-field interactions. This is accompanied …

Spectral Width Of Maximum Deposition Eigenchannels In Diffusive Media, Rohin E. Mcintosh, Arthur Goetschy, Nicholas Bender, Alexey Yamilov, Chia Wei Hsu, Hasan Yllmaz, Hui Cao

Physics Faculty Research & Creative Works

The maximum deposition eigenchannel provides the largest possible power delivery to a target region inside a diffusive medium by optimizing the incident wavefront of a monochromatic beam. It originates from constructive interference of scattered waves, which is frequency sensitive. We investigate the spectral width of the maximum deposition eigenchannels over a range of target depths using numerical simulations of a 2D diffusive system. Compared to tight focusing into the system, power deposition to an extended region is more sensitive to frequency detuning. The spectral width of enhanced delivery to a large target displays a rather weak, nonmonotonic variation with target …

Tunable Pairing With Local Spin-Dependent Rydberg Molecule Potentials In An Atomic Fermi Superfluid, Chih Chun Chien, Seth T. Rittenhouse, S. I. Mistakidis, H. R. Sadeghpour

Physics Faculty Research & Creative Works

We explore the energy spectrum and eigenstates of two-component atomic Fermi superfluids with tunable pairing interactions in the presence of spin-dependent ultralong-range Rydberg molecule (ULRM) potentials, within the Bogoliubov-de Gennes formalism. The attractive ULRM potentials lead to local-density accumulation, while their difference results in a local polarization potential and induces the in-gap Yu-Shiba-Rusinov (YSR) states whose energies lie below the bulk energy gap. A transition from equal population to population imbalance occurs as the pairing strength falls below a critical value, accompanied by the emergence of local Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)-like states characterized by out-of-phase wave functions and lower energies compared to …

Radiative Energy And Mass Shifts Of Quantum Cyclotron States, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

Abstract: We discuss relativistic and radiative corrections to the energies of quantum cyclotron states. In particular, it is shown analytically that the leading logarithmic radiative (self-energy) correction to the bound-state energy levels of quantum cyclotron states is state independent and must be interpreted as a magnetic field-dependent correction to the electron's mass in a Penning trap.

Influence Of The Impact Parameter For Ionization Of Argon By Fast Positrons And Electrons On The Postcollision Kinematics And Triply Differential Spectra, Robert D. Dubois, K. Tokési

Physics Faculty Research & Creative Works

Classical trajectory Monte Carlo calculations for fast positron and electron impact ionization of argon are used to provide information about how the pre- and post collision kinematics alter the triply differential spectra. It is shown that in addition to the scattering direction expected for a positive or negative projectile passing near a partially screened nuclear charge, scattering in the opposite direction also occurs. Independent of energy transfer, when the impact parameter is less than the mean radius of the 3p electron cloud, the expected direction of scattering always occurs. In contrast, for scattering in the opposite direction, the impact parameter …

Silverrush. Xiv. Lyα Luminosity Functions And Angular Correlation Functions From 20,000 Lyα Emitters At Z ∼ 2.2-7.3 From Up To 24 Deg2 Hsc-Ssp And Chorus Surveys: Linking The Postreionization Epoch To The Heart Of Reionization, Hiroya Umeda, Masami Ouchi, Satoshi Kikuta, Yuichi Harikane, Yoshiaki Ono, Takatoshi Shibuya, Akio K. Inoue, Kazuhiro Shimasaku, Yongming Liang, Akinori Matsumoto, Shun Saito, Haruka Kusakabe, Yuta Kageura

Physics Faculty Research & Creative Works

We present luminosity functions (LFs) and angular correlation functions (ACFs) derived from 18,960 Lyα emitters (LAEs) at z = 2.2−7.3 over a wide survey area of ≲24 deg² that are identified in the narrowband data of the HSC-SSP and CHORUS surveys. Confirming the large sample with 241 spectroscopically identified LAEs, we determine Lyα LFs and ACFs in the brighter luminosity range down to 0.5L⋆, and confirm that our measurements are consistent with previous studies but offer significantly reduced statistical uncertainties. The improved precision of our ACFs allows us to clearly detect one-halo terms at some redshifts, and provides large-scale …

A Personalized And Adaptive Distribution Classification Of Actigraphy Segments Into Sleep-Wake States, Austin G. Vandegriffe, V. A. Samaranayake, Matthew S. Thimgan

Research Data

Wearable actimeters have the potential to greatly improve our understanding sleep in natural environments and in long-term experiments. Current technologies have served the sleep community well, but they have known weaknesses that introduce errors that can compromise reliable and relevant clinical and research sleep and wakefulness profiles from these data. Newer data collection technologies, such as microelectromechanical systems (MEMS), offer opportunities to gather movement data in different forms and at higher frequencies, making new analytical methods possible and potentially advantageous.

We have developed a novel statistical algorithm, called the Wasserstein Algorithm for Classifying Sleep and Wakefulness (WACSAW), that is based …

Analytical Dispatch Strategies For Pumped Storage Hydro: A Conditional Dynamic Programming Approach To Discontinuous Multi-Period Optimization Problems, Jian Liu, Jianwen Zhang, Zaiwu Gong, Donald C. Wunsch, Rui Bo

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing integration of renewable energy sources like wind and solar poses significant challenges to secure and stable grid operation. Energy storage systems, particularly pumped storage hydro (PSH), play a crucial role in balancing power supply and demand. Traditional analytical studies of PSH economic dispatch problems often assume zero lower bounds for generating and pumping rates to simplify analysis and derive analytical solutions for multi-period optimization problems. However, the inherent mechanical design constraints of PSH require non-zero minimum flow rates for efficient operation. We analyze two scenarios, merchants having PSH only and merchants having both PSH and wind farms. In …

Generic Transverse Stability Of Kink Structures In Atomic And Optical Nonlinear Media With Competing Attractive And Repulsive Interactions, S. I. Mistakidis, G. Bougas, G. C. Katsimiga, P. G. Kevrekidis

Physics Faculty Research & Creative Works

We demonstrate the existence and stability of one-dimensional (1D) topological kink configurations immersed in higher-dimensional bosonic gases and nonlinear optical setups. Our analysis pertains, in particular, to the two- and three-dimensional extended Gross-Pitaevskii models with quantum fluctuations describing droplet-bearing environments but also to the two-dimensional cubic-quintic nonlinear Schrödinger equation containing higher-order corrections to the nonlinear refractive index. Contrary to the generic dark soliton transverse instability, the kink structures are generically robust under the interplay of low-amplitude attractive and high-amplitude repulsive interactions. A quasi-1D effective potential picture dictates the existence of these defects, while their stability is obtained numerically and analytically …

Synergy In Materials: Leveraging Phosphosilicate Waste Forms For Electrochemical Salt Waste, Jonathan S. Evarts, Brian J. Riley, Charmayne E. Lonergan, Michaella S. Harris, Jincheng Bai, Eric W. Bohannan, Iheanyichukwu Ajoku, Saehwa Chong, John S. Mccloy

Materials Science and Engineering Faculty Research & Creative Works

Waste forms containing glassy and crystalline phosphate and silicate phases were produced to immobilize salt waste simulants from pyro processing and characterized by using Raman spectroscopy, Mössbauer spectroscopy, X-ray diffraction, scanning electron microscopy, heat capacity, and chemical durability measurements. In this work, a phosphosilicate waste form is presented to leverage the benefits of both borosilicate glasses and iron phosphate glasses. To improve waste loading, prior to immobilization, salt simulants were successfully dechlorinated using ammonium dihydrogen phosphate, mixed with a borosilicate frit (5–30 wt. %) and Fe2O3, and vitrified. Additions of 2.5–15 wt. % borosilicate glass (NBS3) improved normalized release rates …

Per- And Polyfluoroalkyl Substance (Pfas) Degradation In Water And Soil Using Cold Atmospheric Plasma (Cap): A Review, Victor Somtochukwu Mbanugo, Boluwatife Stephen Ojo, Ta Chun Lin, Yue-Wern Huang, Marek Locmelis, Daoru Han

Biological Sciences Faculty Research & Creative Works

Per- and polyfluoroalkyl substances (PFASs) are persistent organic chemicals found in numerous industrial applications and everyday products. The excessive amounts of PFASs in water and soil, together with their link to severe health issues, have prompted substantial public concerns, making their removal from the environment a necessity. Existing degradation techniques are frequently lacking due to their low efficiency, cost-effectiveness, and potential for secondary contamination. Cold Atmospheric Plasma (CAP) technology has emerged as a promising alternative, utilizing energized reactive species to break down PFASs under ambient conditions. Therefore, this review examines the efficacy and effectiveness of CAP in degrading PFASs by …

Local Structure Of Zinc-Indium-Tin Oxide Films Via Grazing-Incidence X-Ray Pair-Distribution Functions And Theoretical Methods, G. B. González, C. J. Benmore, Julia E. Medvedeva, J. S. Okasinski, C. Riegger, O. Medina, M. M. Stulajter, T. Bsaibes, G. Cardenas, S. Cone, K. Edlund, M. Osorio, T. Holmes, I. Zhuravlev

Physics Faculty Research & Creative Works

A detailed experimental and theoretical study on the local (r ≤ 4.5 Å) atomic structure of amorphous and crystalline zinc-indium-tin oxide (ZITO) thin films using grazing-incidence x-ray Pair-Distribution Functions (PDFs), ab initio Molecular Dynamics (MD), and Empirical Potential Structure Refinement (EPSR) Monte Carlo simulations is presented. High-energy synchrotron x rays, a two-dimensional detector, and different incident angles were used to probe the depth uniformity of five (ZnO)0.15 (In2O3)0.70 (SnO2)0.15 films that were deposited via pulsed-laser deposition at growth temperatures (TG) ranging from 25 to 300 °C. Films deposited at TG ≤ 150 °C were amorphous. The partially crystalline (TG = …

Coupled Oscillators And Dielectric Function, T. Das, C. A. Ullrich, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

A generalized Sellmeier model, also referred to as the Lorentz-Dirac model, has been used for the description of the dielectric function of a number of technologically important materials in the literature. This model represents the frequency-dependent dielectric function as a sum over Green functions of classical damped harmonic oscillators, much in analogy with the functional form used for the dynamic polarizability of an atom, but with one important addition, namely, a complex-valued oscillator strength in the numerator. Here, we show that this generalized functional form can be justified based on the response function of coupled damped oscillators. The encountered analogies …

Refugium Amidst Ruins: Unearthing The Lost Flora That Escaped The End-Permian Mass Extinction, Huiping Peng, Wan Yang, Mingli Wan, Jun Liu, Feng Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Searching for land refugia becomes imperative for human survival during the hypothetical sixth mass extinction. Studying past comparable crises can offer insights, but there is no fossil evidence of diverse megafloral ecosystems surviving the largest Phanerozoic biodiversity crisis. Here, we investigated palynomorphs, plant, and tetrapod fossils from the Permian-Triassic South Taodonggou Section in Xinjiang, China. Our fossil records, calibrated by a high-resolution age model, reveal the presence of vibrant regional gymnospermous forests and fern fields, while marine organisms experienced mass extinction. This refugial vegetation was crucial for nourishing the substantial influx of surviving animals, thereby establishing a diverse terrestrial ecosystem …

Intelligent Turning Cyber-Physical Systems Modeling Using Sysml, Prithbey Raj Dey, David Lee Enke, Mario F. Buchely

Engineering Management and Systems Engineering Faculty Research & Creative Works

Cyber-Physical Systems (CPS) support industrial automation that incorporates people, hardware, signal, computation, and control using networking to achieve desired results. The complex automated CPS design demands a standard and comprehensive approach to appropriately identify the system requirements, define the architecture, and model the relationships among the software and hardware components. Systems Modeling Language (SysML) provides the capability for a comprehensive modeling to capture the desired design requirements in the systems architecture. SysML enables performance estimation of the model by analyzing constraints while identifying interactions among the components through various behavioral diagrams. In this paper, SysML is applied to the design …

The Interplay Between Endothelial Glycocalyx Maturity And Both The Toxicity And Intracellular Uptake Of Charged Nanoparticles, Claire A. Bridges, Lu D. Fu, Jonathan A. Yeow, Xiaojing D. Huang, Miriam D. Jackson, Rhiannon P. Kuchel, James D. Sterling, Shenda M. Baker, Megan S. Lord

Business and Information Technology Faculty Research & Creative Works

Nanoparticles are widely studied for delivering treatments to target tissues, but few have reached clinical use. Most nanoparticles encounter blood vessels on their way to target tissues. The inner surface of these vessels is lined with endothelial cells covered by a glycocalyx, an extracellular matrix rich in anionic glycans. The role of the glycocalyx in nanoparticle interactions is not well understood. Here, we demonstrate that endothelial cells need extended culture times to synthesize a mature glycocalyx. Our research shows that branched polyethyleneimine functionalized gold nanoparticles bind to endothelial cells expressing either a developing or mature glycocalyx, with the interaction involving …

Mineralogic Control On The Calcium And Magnesium Stable Isotopic Compositions Of Modern Microbial Carbonates, Elizabeth M. Griffith, Matthew S. Fantle, Brittan V. Wogsland, Zijian Li, Majie Fan, David J. Wronkiewicz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Modern microbialites grow in a variety of environments including the hypersaline, turbid, low alkalinity, high magnesium (Mg) and calcium (Ca) concentrations (and Mg/Ca ∼ 4.5 mol/mol), shallow (less than 2 m deep) Storr's Lake on San Salvador Island, The Bahamas. Rather than growing via the trapping and binding of sediments, these largely micritic microbialites form via microbial processes creating crusts and mounds with laminated to clotted structures comprised of both high-Mg calcite and aragonite. The primary objective of this study was to determine whether the mineralogy of representative microbialite mounds dictates their pre-burial metal isotopic compositions. The Mg and Ca …

The Effect Of Mold Flux Wetting Conditions With Varying Crucible Materials On Crystallization, Muhammad Anwarul Nazim, Arezoo Emdadi, Todd Sander, Ronald O'Malley

Materials Science and Engineering Faculty Research & Creative Works

Understanding mold flux crystallization is essential for assessing heat transfer during steel casting. The complexity of the mold gap presents challenges in identifying the optimal testing method and nucleation type. This study investigates how variations in wetting properties influence nucleation dynamics, in particular the wetting behaviors of mold flux in platinum and graphite crucibles and how they affect crystallization temperatures and solidification mechanisms. Advanced analytical techniques, including confocal laser scanning microscopy (CLSM), and differential scanning calorimetry (DSC) were employed to analyze nucleation under different conditions, with calibration using synthetic slag, Li2SO4, and thermodynamic equilibrium simulations. The findings highlight the crucial …

Dynamic Tensile Properties Of Thermally Treated Concrete Specimens Subjected To Varied Heating Rates: An Investigation Using The Digital Image Correlation Method, Ronghua Shu, Jiabao Cheng, Guang Xu, Yuzhang Lai, Lijinhong Huang

Mining Engineering Faculty Research & Creative Works

In concrete engineering, high temperatures at varying heating rates significantly affect the stability of concrete structures. In this paper, the dynamic tensile characteristics were investigated on concrete specimens subjected to heating rates ranging from 2 to 40 °C/min, using the digital image correlation (DIC) method. The results reveal a critical heating rate threshold, between 5 and 10 °C/min, which marks a shift in the influence of heating rates on both physical and dynamic tensile properties. Below this threshold, changes are minimal, but beyond it, significant effects are observed. As the heating rate increases, longitudinal wave velocity, density, and mass decrease, …

Irreducible Three-Loop Vacuum-Polarization Correction In Muonic Bound Systems, Gregory S. Adkins, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

Three-loop electronic vacuum-polarization corrections due to irreducible diagrams are evaluated for two-body muonic ions with nuclear charge numbers 1≤Z≤6. The corrections are of order α3(Zα)2mr, where α is the fine-structure constant and mr is the reduced mass. Numerically, the energy corrections are found to be of the same order of magnitude as the largest of the order α2(Zα)6mr corrections, and are thus phenomenologically interesting. Our method of calculation eliminates numerical uncertainty encountered in other approaches.

Phases And Phase Transitions Of The Disordered Quantum Clock Model, Pulloor Kuttanikkad Vishnu, Gaurav Khairnar, Rajesh Narayanan, Thomas Vojta

Physics Faculty Research & Creative Works

We study the phases and phase transitions of a disordered one-dimensional quantum q-state clock Hamiltonian using large-scale Monte Carlo simulations. Making contact with earlier results, we confirm that the clean, translational invariant version of the model, for q=6, hosts an intermediate emergent quasi-long-range ordered (QLRO) phase between the symmetry-broken true long-range ordered (TLRO) phase and the disordered (paramagnetic) phase. With increasing disorder strength, the quasi-long-range ordered phase shrinks and finally vanishes at a multicritical point, beyond which there is a direct transition from the TLRO phase to the paramagnetic phase. After establishing the phase diagram, we characterize the critical behaviors …

Impact Of Aggregate Characteristics On Frictional Performance Of Asphalt-Based High Friction Surface Treatments, Alireza Roshan, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

High Friction Surface Treatments (HFST) are recognized for their effectiveness in enhancing skid resistance and reducing road accidents. While Epoxy-based HFSTs are widely applied, they present limitations such as compatibility issues with existing pavements, high installation and removal costs, and durability concerns tied to substrate quality. As an alternative to traditional Epoxy-based HFSTs, this study investigated the effects of aggregate gradation as designated by agencies on the performance of asphalt-based HFST. Various aggregate types were assessed to evaluate friction performance and the impact of polishing cycles on non-Epoxy HFST. It was found that adjustments in aggregate size and gradation may …

Correlating The Compositional Changes To The Rheological Properties Of Recovered Asphalt Binders From Recycled Asphalt Mixtures: Insights From The Thermogravimetric Measurements, Eslam Deef-Allah, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Assessing the binder performance of thermal characterization is critical for quality control. This is pertinent for recovered binders from mixtures, which may not be in adequate quantities to evaluate their performance, particularly in mixtures containing reclaimed asphalt pavement (RAP). The present study deployed a thermogravimetric analyzer to evaluate compositional changes in recovered binders from RAP-containing mixtures, focusing on thermograph and derivative of thermograph (DTG) characteristics and correlating the results to rheological features. Incorporating RAP in mixtures influenced recovered binders' DTG shapes, reducing low-combusted components (%LCC) and increasing residues (%R). The recovered binder from the zero-RAP-containing mixture showed a 4.36% increase …

Understanding The Underlying Trends In Us Construction Labor Wages: A Data-Driven Mixed-Method Computational Approach, Bahaa Chammout, Islam H. El-Adaway

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Precisely forecasting construction costs is crucial for maintaining financial stability for contractors and the broader construction sector. Nonetheless, this task has long been acknowledged as challenging. Recent global events and inflationary pressures have notably driven up construction labor expenses. While existing research examined labor shortages, there remains a gap in understanding the diverse labor wage trends. This paper addresses this research gap following a multistep methodology, which included: (1) gathering construction labor data from 1999 to 2023; (2) conducting trend and statistical analyses to discern the underlying patterns in labor trends; (3) employing clustering analysis to categorize construction occupations based …

March 2025 Cafe Newsleter, Center For Advancing Faculty Excellence

CAFE Faculty Newsletters

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Structure-Property Relations Of Binary Ferrite Melts, C. J. Benmore, C. Shi, O. L.G. Alderman, J. P. Harvey, D. Lipke, J. K.R. Weber

Materials Science and Engineering Faculty Research & Creative Works

Molten ferrite systems are used in the smelting and refining processes in steelmaking, to reduce the loss of metals in slags and to accelerate reaction rates. Here, high-energy x-ray diffraction experiments have been performed on aerodynamically levitated molten spheres of 43BaO-57FeOX and 43SrO-57FeOX at 1873 K using laser beam heating. The composition was varied within the range of x = 1-1.5 by changing the oxygen partial pressure of the levitation gas. The corresponding x-ray pair distribution functions have been interpreted using empirical potential structure refinement (EPSR) modeling. In oxygen-rich melts (x = 1.5), our EPSR models indicate very similar structures …

A Comprehensive Survey Of Data-Driven Solutions For Lorawan: Challenges And Future Directions, Poonam Maurya, Abhishek Hazra, Preti Kumari, Troels Bundgaard Sørensen, Sajal K. Das

Computer Science Faculty Research & Creative Works

Long-range Wide-area Network (LoRaWAN) is an innovative and prominent communication protocol in the domain of Low-power Wide-area Networks (LPWAN), known for its ability to provide long-range communication with low energy consumption. However, the practical implementation of the LoRaWAN protocol, operating at the Medium Access Control layer and specially built to work upon the LoRa physical layer, presents numerous research challenges, including network congestion, interference, optimal resource allocation, collisions, scalability, and security. To mitigate these challenges effectively, the adoption of cutting-edge data-driven technologies such as Deep Learning (DL) and Machine Learning (ML) emerges as a promising approach. Interestingly, very few existing …