Digital Commons Network^™

Performance Enhancement Of Crumb Rubber-Modified Asphalts Through Control Of The Developed Internal Network Structure, Mohyeldin Ragab, Magdy Abdelrahman, Amir Ghavibzaoo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Control of the internal network structure of crumb rubber-modified asphalt (CRMA) was investigated for its effect on property development in the study presented in this paper. The investigation included evaluation by rheological and interrupted shear tests. Rheological testing involved the monitoring of the changes of the produced complex modulus (G*) and phase angle (δ) for CRMA. In the interrupted shear tests, the shear stress profile for the produced CRMA was investigated. It was found that triggering the critical conditions of the combined interaction of speed, temperature, and time was essential to inducing the formation of the three-dimensional network …

Elevated Electron Temperatures Around Twin Sporadic E Layers At Low Latitude: Observations And The Case For A Plausible Link To Currents Parallel To The Geomagnetic Field, A. Barjatya, J. P. St. Maurice, C. M. Swenson

Publications

We present data from nighttime sounding rocket flights in the low latitude E region. The payloads carried a sweeping Langmuir probe, a plasma impedance probe, and electric field probes. A detailed examination of the plasma density, temperature, and electric field measurements show two strong sporadic E (Es) layers with very high electron temperatures (∼1000 K) on each side of the upper layer. The lower layer was consistent with the presence of a strong zonal neutral wind shear. The upper layer was strongly influenced by the presence of a strongly negative vertical electric field, with zonal winds and …

Exploring Current And Projected Skills And Knowledge Areas To Meet U.S. Commercial Space Industry Needs, Sonya A. H. Mcmullen, Mac J. Mcmullen, Kenneth Witcher

Publications

In 2007, the Committee on Meeting the Workforce Needs for the National Vision for Space Exploration published findings related to age and skills of the current National Aeronautics and Space Administration (NASA) workforce and projected potential expertise shortages as a result of retirement in the 2014-2015 time frame. In addition, the expanding commercial space industry in both the United States and Europe will likely create further demand for space experts in engineering and a variety of related fields. Although NASA contributes $162 million in funding for education programs annually, those programs target kindergarten through grade 12, not collegiate-level programs. Further, …

Location Based Services In Wireless Ad Hoc Networks, Neelanjana Dutta

Doctoral Dissertations

"In this dissertation, we investigate location based services in wireless ad hoc networks from four different aspects - i) location privacy in wireless sensor networks (privacy), ii) end-to-end secure communication in randomly deployed wireless sensor networks (security), iii) quality versus latency trade-off in content retrieval under ad hoc node mobility (performance) and iv) location clustering based Sybil attack detection in vehicular ad hoc networks (trust). The first contribution of this dissertation is in addressing location privacy in wireless sensor networks. We propose a non-cooperative sensor localization algorithm showing how an external entity can stealthily invade into the location privacy of …

Palynology Of Acid-Saline Lakes Of Western Australiabiostratigraphy And Paleoenvironmental Reconstruction, Carlos A. Sanchez Botero

Doctoral Dissertations

"Lakes are excellent repositories of fossils and sedimentary features that provide clues to past climatic and geologic events. Sediments from four cores drilled in Lake Aerodrome (LA1-09, LA2-09) and Lake Brown (LB1-09, LB2-09), two of the hundreds of ephemeral lakes in southern Western Australia, were analyzed for their palynological contents to understand the geologic and climatic evolution of the depositional basin. Palynofacies assemblages defined by statistical analyses of dispersed organic matter suggested differences in the depositional conditions and probable correlations between Lake Aerodrome cores. Detailed identifications and quantification of organic-walled microfossils yielded two palynomorph assemblages that reflect a climatic turnover: …

A Regional Study Of Landslide Hazards And Related Features In The Upper Indus River Basin, Northern Pakistan, Muhammad Farooq Ahmed

Doctoral Dissertations

"A spatial landslide inventory is a fundamental step preparatory to developing an understanding of regional landslide hazards. The techniques honed for this regional landslide mapping study began with compiling a stitched shaded topographic map of the Upper Indus River watershed; using remotely-sensed topographic maps from Russia combined with ASTER DEM 30m resolution data. Topographic recognition keys were then employed to aid in the visual identification and delineation of past landslides, rockslide avalanches, and landslide dam sites. The first order reconnaissance level inventory excerpted 2,254 landslides (mostly deep seated translational and complex slides) along the main stem of Indus River, land …

Advances In Blind Source Separation, Christopher Osterwise

Doctoral Dissertations

"Blind Source Separation (BSS) is a classic problem that attempts to separate unknown sources from observed mixtures. A common framework of this is the Cocktail Party problem, where multiple individuals speaking in a noisy room are recorded by a configuration of microphones, with the challenge being to split the observed signals into individual conversations. This dissertation covers the evaluation of an existing algorithm known as Cascaded ICA with Intervention Alignment (CICAIA), the establishment of a new parameter for characterizing blind mixtures, and three new algorithms, of which two are capable of separating any number of sources given more microphones than …

Real Options Modeling And Valuation Of Price Adjustment Flexibility With An Application To The Leasing Industry, Ahmed A. A. Al Sharif

Doctoral Dissertations

"Uncertainty poses not only threats but also opportunities. This study sought to build the scientific foundation for introducing a real options (ROs) methodology for price risk management to the leasing industry. A price risk management that allows for both coping with threats and taking advantage of opportunities. In the leasing industry, fixed rate long-term lease contracts help contract parties stabilize cash flows within volatile markets. The contract's term, however, may be extended long enough that prevent capturing the opportunities of gaining greater profits or reducing expenses. Therefore, the flexibility that enables participants to take advantage of favorable market price is …

Detecting And Locating Electronic Devices Using Their Unintended Electromagnetic Emissions, Colin Stagner

Doctoral Dissertations

"Electronically-initiated explosives can have unintended electromagnetic emissions which propagate through walls and sealed containers. These emissions, if properly characterized, enable the prompt and accurate detection of explosive threats. The following dissertation develops and evaluates techniques for detecting and locating common electronic initiators. The unintended emissions of radio receivers and microcontrollers are analyzed. These emissions are low-power radio signals that result from the device's normal operation. In the first section, it is demonstrated that arbitrary signals can be injected into a radio receiver's unintended emissions using a relatively weak stimulation signal. This effect is called stimulated emissions. The performance of stimulated …

Dynamic Modeling, Stability Analysis, And Controller Design For Dc Distribution Systems, Reza Ahmadi

Doctoral Dissertations

"The dc distribution systems or dc microgrids are known to be best suited for integration of renewable energy sources into the current power grid and are considered to be the key enabling technology for the development of future smart grid. Dc microgrids also benefit from better current capabilities of dc power lines, better short circuit protection, and transformer-less conversion of voltage levels, which result in higher efficiency, flexibility, and lower cost. While the idea of using a dc microgrid to interface distributed energy sources and modern loads to the power grid seems appealing at first, several issues must be addressed …

Contested Shore: Property Rights In Reclaimed Land And The Battle For Streeterville, Joseph D. Kearney, Thomas W. Merrill

Faculty Scholarship

Land reclaimed from navigable waters is a resource uniquely susceptible to conflict. The multiple reasons for this include traditional hostility to interference with navigable waterways and the weakness of rights in submerged land. In Illinois, title to land reclaimed from Lake Michigan was further clouded by a shift in judicial understanding in the late nineteenth century about who owned the submerged land, starting with an assumption of private ownership but eventually embracing state ownership. The potential for such legal uncertainty to produce conflict is vividly illustrated by the history of the area of Chicago known as Streeterville, the area of …

Contract And Innovation: The Limited Role Of Generalist Courts In The Evolution Of Novel Contractual Forms, Ronald J. Gilson, Charles F. Sabel, Robert E. Scott

Faculty Scholarship

In developing a contractual response to changes in the economic environment, parties choose the method by which their innovation will be adapted to the particulars of their context. These choices are driven centrally by the thickness of the relevant market – the number of actors who see themselves as facing similar circumstances – and the uncertainty related to that market. In turn, the parties' choice of method will shape how generalist courts can best support the parties' innovation and the novel regimes they envision. In this Article, we argue that contractual innovation does not come to courts incrementally, but instead …

Extending The Minimal Learning Machine For Pattern Classification, Amauri H.Souza Junior, Francesco Corona, Yoan Miche, Amaury Lendasse, Guilherme A. Barreto

Engineering Management and Systems Engineering Faculty Research & Creative Works

The Minimal Learning Machine (MLM) Has Been Recently Proposed as a Novel Supervised Learning Method for Regression Problems Aiming at Reconstructing the Mapping between Input and Output Distance Matrices. Estimation of the Response is Then Achieved from the Geometrical Configuration of the Output Points. Thanks to its Comprehensive Formulation, the MLM is Inherently Capable of Dealing with Nonlinear Problems and Multidimensional Output Spaces. in This Paper, We Introduce an Extension of the MLM to Classification Tasks, Thus Providing a Unified Framework for Mult response Regression and Classification Problems. on the Basis of Our Experiments, the MLM Achieves Results that Are …

Data Preprocessing And Model Design For Medicine Problems, Alberto Guillén, Amaury Lendasse, Guilherme Barreto

Engineering Management and Systems Engineering Faculty Research & Creative Works

No abstract provided.

Efficient Uncertainty Quantification In Aerospace Analysis And Design, Yi Zhang

Doctoral Dissertations

"The main purpose of this study is to apply a computationally efficient uncertainty quantification approach, Non-Intrusive Polynomial Chaos (NIPC) based stochastic expansions, to robust aerospace analysis and design under mixed (aleatory and epistemic) uncertainties and demonstrate this technique on model problems and robust aerodynamic optimization. The proposed optimization approach utilizes stochastic response surfaces obtained with NIPC methods to approximate the objective function and the constraints in the optimization formulation. The objective function includes the stochastic measures which are minimized simultaneously to ensure the robustness of the final design to both aleatory and epistemic uncertainties. For model problems with mixed uncertainties, …

Fiber Inline Pressure And Acoustic Sensor Fabricated With Femtosecond Laser, Yinan Zhang

Doctoral Dissertations

"Pressure and acoustic measurements are required in many industrial applications such as down-hole oil well monitoring, structural heath monitoring, engine monitoring, study of aerodynamics, etc. Conventional sensors are difficult to apply due to the high temperature, electromagnetic-interference noise and limited space in such environments. Fiber optic sensors have been developed since the last century and have proved themselves good candidates in such harsh environment. This dissertation aims to design, develop and demonstrate miniaturized fiber pressure/acoustic sensors for harsh environment applications through femtosecond laser fabrication. Working towards this objective, the dissertation explored two types of fiber inline microsensors fabricated by femtosecond …

Gas Dynamics And Heat Transfer In A Packed Pebble-Bed Reactor For The 4th Generation Nuclear Energy, Rahman Abdulmohsin

Doctoral Dissertations

"Proper analyses of axial dispersion and mixing of the coolant gas flow and heat transport phenomena in the dynamic core of nuclear pebble-bed reactors pose extreme challenges to the safe design and efficient operation of these packed pebble-bed reactors.

The main objectives of the present work are advancing the knowledge of the coolant gas dispersion and extent of mixing and the convective heat transfer coefficients in the studied packed pebble-beds. The study also provides the needed benchmark data for modeling and simulation validation. Hence, a separate effect pilot-plant scale and cold-flow experimental setup was designed, developed and used to carry …

Phytoforensics On Energetics: Novel Plant Tissue Measure Approach And Modeling, Yuan Yuan

Doctoral Dissertations

"Explosives and energetics are common soil and groundwater pollutions. This research was to develop novel phytoforensics approaches on energetics. Four different plants species, including woody perennial trees and monocot grasses, were planted both in soil and sand reactors with continuous exposure to a mixture of explosives in the greenhouse. Time dependent assessments were carried out to determine kinetic mechanisms of uptake, transport and accumulation. Plant concentrations were analyzed by both traditional solvent extraction and novel sap analysis methods. A dynamic soil-plant system model was developed to quantify the relationship between tissue concentration and soil pore water concentration for non-volatile organic …

Processing, Microstructural Evolution And Electrochemical Performance Relationships In Solid Oxide Fuel Cells, Ayhan Sarikaya

Doctoral Dissertations

"The relationships between the processing parameters, microstructures and electrochemical performance of solid oxide fuel cell (SOFC) components were investigated. The operating regimes (i.e., reducing vs. oxidizing) as well as the elevated temperatures (e.g. 800°C) for their operation introduce several material challenges. Therefore, composite materials are employed to withstand operating conditions while providing sufficient electrochemical performance for fuel cell operation. Analyses on lanthanum-strontium manganite (LSM) - yttria stabilized zirconia (YSZ) compositions (45 vol%-55 vol%) by impedance spectroscopy demonstrated that two competing polarization mechanisms (i.e. charge-exchange and surface adsorption-diffusion of oxygen) limit performance. Optimization of microstructures resulted in total resistances as low …

Recycling Of Electronic Waste: Printed Wiring Boards, Alex Luyima

Doctoral Dissertations

"Pyrolysis and leaching are the dominant techniques applied in the recycling of waste printed wiring boards (PWBs). Waste PWB pyrolysis is a highly polluting technology and produces brominated pyrolysis oils in addition to hydrogen bromide (HBr) gas. Moreover, leaching as a treatment process of waste PWBs is not well investigated. In this work, the pyrolysis of waste PWBs has been studied with the aim of reducing the amount of brominated oils and HBr gas evolved. The effects of powder inorganic chemicals (CaO, CaCO₃, Fe₂O₃, Al₂O₃, Y-Zeolite, and ZSM-5) additions on the pyrolysis of waste PWBs has been studied through experiments …

Risk Analysis: Comparative Study Of Various Techniques, Hanan Mohammad Altabbakh

Doctoral Dissertations

"Researchers in the safety field are facing more challenges everyday with the expanding modern socio-technical systems. Safety analysis such as hazard analysis, accident causation analysis, and risk assessment are being revisited to overcome the shortcoming of the conventional safety analysis. With increasingly complex human system interaction in today's modern systems, new safety challenges are being faced that needed to be assessed and addressed. Managers and engineers face the challenge to choose from the vast amount of techniques available and utilize the correct one. Indeed, new or improved risk assessment tools that can address these complexities are needed. One of the …

Shear And Fracture Behavior Of High Performance Concretes, Mahdi Arezoumandi

Doctoral Dissertations

"Concrete is the most widely used man-made material in the world. Like other materials, it has been improved over time. Nowadays, with continued development of science and technology, a new generation of concretes is produced and is termed high performance concretes. A review of previously published work indicates that very few studies (in some cases none) have addressed the structural behavior of full-scale, high performance concrete elements. This study investigated the shear and fracture behavior of two types of high performance concrete - high-volume fly ash concrete (HVFAC) and self-consolidating concrete (SCC). The HVFAC incorporates up to 70% cement replacement …

Social-Context Based Routing And Security In Delay Tolerant Networks, Roy A. Cabaniss

Doctoral Dissertations

"Delay Tolerant Networks (DTNs) were originally intended for interplanetary communications and have been applied to a series of difficult environments: wireless sensor networks, unmanned aerial vehicles, and short-range personal communications. There is a class of such environments in which nodes follow semi-predictable social patterns, such as wildlife tracking or personal devices. This work introduces a series of algorithms designed to identify the social patterns present in these environments and apply this data to difficult problems, such as efficient message routing and content distribution. Security is also difficult in a mobile environment. This is especially the case in the event that …

Bioactive Glass Scaffolds For The Regeneration Of Load-Bearing Bone, Xin Liu

Doctoral Dissertations

"Biocompatible scaffolds that replicate the structure and function of bone would be ideal bone substitutes for structural bone loss, provided they have the requisite mechanical properties for reliable long-term loading. In this dissertation, strong porous scaffolds of silicate 13-93 bioactive glass, created with two different microstructures, were evaluated to determine their mechanical properties and their capacity to regenerate bone in a rat calvarial defect model. Scaffolds with an oriented microstructure of columnar pores were prepared by unidirectional freezing of camphene-based suspensions, followed by thermal annealing and sintering. By optimizing the freezing conditions, annealing time, and sintering temperature, constructs (porosity = …

Two Essays On Dynamic Programming And Reinforcement Learning, Shuva Ghosh

Doctoral Dissertations

"The semi-Markov decision process (SMDP) is a variant of the Markov decision process (MOP). This dissertation work focuses on the application of SMDPs to disaster response management and to maintenance management. Average and discounted reward are two popular performance metrics for MDPs/SMDPs. While both dynamic programming (DP) methods, i.e., value iteration and policy iteration, are commonly used to solve MDPs/SMDPs, value iteration is easier to apply than policy iteration. The existing value iteration algorithms for average reward SMDPs have some noteworthy limitations, which are sought to be overcome in this work. Reinforcement learning (RL) techniques, which are also studied in …

Nanoscale Metal Oxide And Supported Metal Catalysts For Li-Air Battery, Kan Huang

Doctoral Dissertations

"The dissertation work focuses on research and development of durable nanoscale catalysts and supports for rechargeable Li-air batteries that use aqueous catholytes. Transition metal oxides, TiO₂ and Nb₂O₅ in particular, were prepared from a sol-gel process in the form of nanocoatings (5~50 nm) on carbon nanotubes (CNTs) and studied as catalyst supports. Carbon doping in the oxides and post annealing significantly increased their electronic conductivity. Pt catalyst on the support with TiO₂ (Pt/c-TiO₂/CNTs) showed a much better oxygen reduction reaction (ORR) activity than a commercial Pt on carbon black (Pt/C). Negligible loss ( …

Approximate Dynamic Programming Based Solutions For Fixed-Final-Time Optimal Control And Optimal Switching, Ali Heydari

Doctoral Dissertations

"Optimal solutions with neural networks (NN) based on an approximate dynamic programming (ADP) framework for new classes of engineering and non-engineering problems and associated difficulties and challenges are investigated in this dissertation. In the enclosed eight papers, the ADP framework is utilized for solving fixed-final-time problems (also called terminal control problems) and problems with switching nature. An ADP based algorithm is proposed in Paper 1 for solving fixed-final-time problems with soft terminal constraint, in which, a single neural network with a single set of weights is utilized. Paper 2 investigates fixed-final-time problems with hard terminal constraints. The optimality analysis of …

The Sweet Grass Hills And Blackfeet Indians: Sacredness, Land, And Institutional Discrimination, Cassie Sheets

Graduate Student Theses, Dissertations, & Professional Papers

The Sweet Grass Hills of north-central Montana are part of the four Tribes of the Blackfoot Confederacy’s traditional territory and play a vital role in perpetuating Blackfeet culture. The Blackfeet Tribe of Montana was forced to sell the Sweet Grass Hills to the federal government in 1888 after the decimation of bison populations. In 1992, the first large-scale corporate mining proposal in the Sweet Grass Hills was proposed by Lehmann and Associates and Manhattan Mineral, Ltd. In response to public outcries, environmental impact statements were issued by the Bureau of Land Management, the agency that manages the area, and Secretary …

An Improved Dipole-Moment Model Based On Near-Field Scanning For Characterizing Near-Field Coupling And Far-Field Radiation From An Ic, Zhenwei Yu, Jason A. Mix, Soji Sajuyigbe, Kevin P. Slattery, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an improved dipole-moment model for characterizing near-field coupling and far-field radiation from an IC based on near-field scanning is proposed. An array of electric and magnetic dipole moments is used to reproduce the field distributions in a scanning plane above an IC. These dipole moments can then be used as noise sources for the IC. In order to ensure the accurate prediction of the near-field coupling from the IC, the regularization technique and the truncated singular-value decomposition method are investigated in this paper, together with the conventional least-squares method, to reconstruct the dipole moments from the near-field …

Tests For Time Domain Em Solvers For Stability And Towards Passivity, G. Antonini, Albert E. Ruehli, D. Romano, L. (Lijun) Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Stability issues for time domain integral equation based EM solvers have been a problem for a many years. In this paper, we consider ways to test for stability as well as other criteria towards passivity. The tests are designed to monitor the EM solver while the time domain solution is progressing. Hence, the solution can be terminated and improved with a passivization technique when a violation of the criterion has been detected. Also, the tests help to understand the cause of instabilities and results can be used for passivization. © 2013 IEEE.