Engineering Commons^™

The Dual-Porosity Vertical-Well Model For Transient Pressure Analysis Of Naturally Fractured Shale Gas Reservoirs, Yi Jiang, Rui Xu, Meng Chen

Electrical and Computer Engineering Faculty Research & Creative Works

During the process of development for shale gas reservoirs, the permeability of fractures will decrease due to stress-sensitive effect. Adsorption is also an important mechanism which determines the production of shale gas reservoirs. Therefore, the effect of stress sensitivity and adsorption must be considered in the numerical model for pressure transient analysis. In this paper, a dual-porosity model was established considering both mechanisms, and finite-difference method was used for discretizing fluid equations. Then Newton method was applied for solving the resulting algebraic equations, and the typical curves in terms of dimensionless pseudo pressure and time were drawn with different sets …

Variability-Aware Parametric Yield Estimation For Analog/Mixed-Signal Circuits: Concepts, Algorithms, And Challenges, Fang Gong, Yiyu Shi, Hao Yu, Lei He

Electrical and Computer Engineering Faculty Research & Creative Works

The undesired uncertainties in circuit performance can lead to analog/mixed-signal circuit failures and yield loss at nanoscale. As such, it has become extremely critical for high precision analog/RF circuits such as phase-locked loop (PLL) and custom/mixed-signal circuits such as SRAM arrays, which both have tight operating margin due to lower power supply and higher operating frequency. Many performance-domain techniques have become available in past few decades: the Monte Carlo (MC) method repeatedly draws samples, runs simulations, and evaluates the yield rate, which can be easily applied to high-dimensional problems. However, it is extremely time consuming. IS can reduce the number …

Economic Scheduling Of Residential Plug-In (Hybrid) Electric Vehicle (Phev) Charging, Maigha, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

In the past decade, plug-in (hybrid) electric vehicles (PHEVs) have been widely proposed as a viable alternative to internal combustion vehicles to reduce fossil fuel emissions and dependence on petroleum. Off-peak vehicle charging is frequently proposed to reduce the stress on the electric power grid by shaping the load curve. Time of use (TOU) rates have been recommended to incentivize PHEV owners to shift their charging patterns. Many utilities are not currently equipped to provide real-time use rates to their customers but can provide two or three staggered rate levels. To date, an analysis of the optimal number of levels …

The Soft-Feedback Isi Canceller-Based Turbo Equalizer For Multilevel Modulations, Huang Lou, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate the soft-feedback equalizer (SFE) proposed by Lopes et al. for multilevel modulations. The SFE is based on InterSymbol interference canceller structure and is compared to both soft-decision feedback turbo equalizer (SDFE) and the exact solution of MMSE linear equalizer (Exact-MMSE-LE) by means of EXIT chart analysis and BER simulations. Interesting results reveal that, for multilevel modulations, the SFE not only exhibits the same low complexity, low SNR threshold and fast convergence as SDFE but also reaches matched filter bound after a large number of iterations. © 2013 Springer Science + Business Media New York.

Thermal Analysis, Microstructural Characterization And Nanoindentation For Electron Beam Additive Manufacturing, Bo Chang, Xibing Gong, Xiaoqing Wang, Kevin Chou

Early Career Technical Journal (ECTJ)

Section 7: Design & Manufacturing; pp. 196-203

Approximate Dynamic Programming, Local Or Global Optimal Solution?, Ali Heydari, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of global optimality analysis of approximate dynamic programming-based solutions is investigated in this study. Sufficient conditions for global optimality are obtained without requiring the state penalizing terms in the cost function or the functions representing the dynamics to be convex functions. Afterwards, the theoretical results are confirmed through a qualitative analysis of an example problem. © 2014 American Automatic Control Council.

Optimal Switching Of Nonlinear Systems With Free Mode Sequence, Ali Heydari, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Approximate dynamic programming is utilized in this study to develop solutions for optimal switching problems. The order of the active subsystems and the number of switches are free, and an online solution is developed that produces optimal performance. Motivated by the development in the adaptive critic's literature, the proposed method uses a critic and as many actors as the number of subsystems in order to conduct optimal scheduling in real-time based on the instantaneous states of the system. It is observed that once the neural networks are trained offline based on the proposed algorithm, they provide solutions for a range …

Investigation Of Mirror Image Bias: Evidence For The Use Of Psychophysiological Measures As Indicators Of Cognitive Heuristics, Caroline R. Salchak

Browse all Theses and Dissertations

The Mirror Imaging Bias (MIB) is gaining attention as a prominent quality factor in analysts' performance. MIB is an irrationality in which analysts perceive and process information through the filter of personal experience. As evidenced by notable historical events, the consequences of this bias can be dramatic. A way to understand MIB in humans is sought. How analysts analyze data, are trained, and interact with biases is explored. An experiment testing for the appearance of MIB was designed and completed. Measures from an eye tracker as well as physiological measures were collected. Results show a significant correlation between pupil diameter …

Multi-Finger Mosfet Low Noise Amplifier Performance Analysis, Xiaomeng Zhang

Browse all Theses and Dissertations

Multi-finger layout technique has been extensively used in Nano-scale CMOS circuit design due to the increased circuit performance compared to a single finger layout. However choosing a finger width (W_f) and number of fingers (N_f) to optimize circuit performance is a challenging problem. In this thesis, the performances of 2.4GHz and 6.0GHz single ended low noise amplifiers (LNA) with fixed total transistor widths in 90nm CMOS technology are analyzed as function of number of fingers, bias voltage (V_bias) and channel length (L). The results show that the drain to source current, transconductance and effective gate capacitance increase with increasing number …

Apelin Regulation Of K-Cl Cotransport In Vascular Smooth Muscle Cells., Neelima Sharma

Browse all Theses and Dissertations

Atherosclerosis and high circulating levels of oxidized low density lipoproteins (oxLDL) are considered among the most important risk factors for the occurrence and development of cardiovascular disease (CVD). During the atherosclerotic lesion repair, phenotypic transition of vascular smooth muscle cells (VSMCs) from contractile to synthetic states plays a central role. In this process, enhanced proliferation/migration of VSMCs, from the tunica media to the intima, is required to sustain blood vessel endothelium integrity, and for inducing vessel wall remodeling in response to injury. At the molecular level, the activity of electroneutral potassium-chloride cotransporters or KCCs, is necessary to: a) allow changes …

Computational Design And Characterization Of Silicene Nanostructures For Electrical And Thermal Transport Applications, Tim H. Osborn

Browse all Theses and Dissertations

Novel silicene-based nanomaterials are designed and characterized by first principle computer simulations to assess the effects of adsorptions and defects on stability, electronic, and thermal properties. To explore quantum thermal transport in nanostructures a general purpose code based on Green's function formalism is developed.

Specifically, we explore the energetics, temperature dependent dynamics, phonon frequencies, and electronic structure associated with lithium chemisorption on silicene. Our results predict the stability of completely lithiated silicene sheets (silicel) in which lithium atoms adsorb on the atom-down sites on both sides of the silicene sheet. Upon complete lithiation, the band structure of silicene is transformed …

Cgt 256: User-Centered (Re)Design, Mihaela Vorvoreanu

IMPACT Symposium

The poster presented at the IMPACT Symposium 2014 outlines the redesign of of CGT 256: User Centered Design.

Motivation Of Community Partners And Advisors To Participate In Community Engagement Engineering Programs, Julia D Thompson, Brent Jesiek

School of Engineering Education Graduate Student Series

Since 2000, research in service-learning has started to investigate partnerships and community voice, but this research trend has received little attention among engineering education scholars. This study aims to fill this gap by developing a richer understanding of community-university partnerships in engineering community engagement from the perspectives of academic programs and served communities. In part inspired by the existing service-learning literature, this study addresses the question: Why are individuals and local community organizations involved in engineering service-learning partnerships? This study utilizes a single case study design, with data collection including in-depth interviews with community partners, faculty and program administrators (n=11) …

Design For The Other 90% And Appropriate Technology: The Legacies Of Paul Polak And E.F. Schumacher, Lindsey Anne Nelson

School of Engineering Education Graduate Student Series

Recent movements showcase engineering design activities on behalf of poor people, inspiring engineering educators to create global service-learning programs. People who encourage engineers to “design for the other 90%” envision globally engaged businesses paving a new way forward for poverty eradication while other engineers pursue forms of “appropriate technology”to create socially-just technological systems. The engineering practices related to these phrases raise questions of which people benefit from engineering design for poverty alleviation, how engineers define “poor” people, what indicates “success” when engineers design for poverty alleviation, and how engineering educators create meaningful global service-learning programs for students.This paper uses mediated …

Analysis Of The Influence Of Organic Corrosion Inhibitors On Corrosion Of Reinforcement In Concrete Bridge Structure Under Simulated Field Service Environment, Liang Shi, J. Ye, C. C. Chen, Y. Wu, J. Z. Liu

International Conference on Durability of Concrete Structures

For concrete bridge projects in marine environments, attention must be paid to the reinforcement corrosion problems caused by chloride intrusion. As kinds of functional admixtures, which can reduce the reinforcement corrosion rate, corrosion inhibitors are becoming very popular in China in new bridge projects. Corrosion inhibitors cover both inorganic and organic inhibitors. Nitrite is representative of inorganic corrosion inhibitors, but its carcinogenicity has hindered its further development. Organic corrosion inhibitors such as small-molecule-based alcohol amine series are becoming the focus of attention. To guide the scientific applications of organic corrosion inhibitors, China is carrying out broad applications technology research. But …

Cognitive Challenges To Resilience Dynamics In Managing Large- Scale Event Response, Barrett S. Caldwell

School of Industrial Engineering Faculty Publications

In early 2014, a number of large-scale adverse weather events in the United States (and elsewhere) have renewed discussions of event response and resilience. Unlike events caused by human error or malicious intent, adverse natural events can be seen as uncontrolled and unpreventable; the measure of response success is the mitigation of adverse and disastrous effects. However, significant cognitive limitations interfere with human decision makers’ ability to effectively estimate likelihood, magnitude, and effective response of large-scale events in the face of multiple forms of uncertainty and system dependencies. Some authors highlight stability and maintenance of original design capability as …

Parents As Critical Influence: Insights From Five Different Studies, Brianna L. Dorie, Tamecia R. Jones, Meagan C Pollock, Monica Cardella

School of Engineering Education Graduate Student Series

Parents play a number of roles in engineering education: they can motivate children’s interest in engineering in early childhood, as well as later when their child is in the process of selecting a major at college, they can provide support in learning engineering concepts and thinking skills, and can serve as role models if they themselves are engineers. Several empirical studies have shown that parents play a significant role in the occupational aspiration and career goal development of their children. In addition,parents’ own beliefs and aspirations have been found to be important factors in children’s career and academic aspirations. In …

Capturing The Design Thinking Of Young Children Interacting With A Parent, Brianna L. Dorie, Monica Cardella, Gina Navoa Svarovsky

School of Engineering Education Graduate Student Series

Children have often been labeled as “natural engineers” whose curiosity about the world around them evokes comparisons to skills used by professional engineers and taught to undergraduate engineering students. Building towers out of blocks, taking things apart and figuring how things work are a part of childhood and have been considered to be precursors to engineering thinking.However there has been considerable debate around what engineering looks like for young children. Can young children engage in design and if so, what does that look like? How can we differentiate “design” (especially “modeling” or “create”) activity from normal everyday play?Several design models …

Concise Handbook For Temporary Traffic Control, Indiana Ltap, Ohio Department Of Transportation

Indiana Local Technical Assistance Program (LTAP) Publications

This handbook gives the basic principles and provides examples for the design, application, installation, and maintenance of the various types of traffic control devices used in temporary traffic control or for incident management. The guidelines presented are in accordance with the standards provided within the Indiana Manual for Uniform Traffic Control Devices (IMUTCD). This handbook is based upon one created by the Ohio Department of Transportation, Guidelines for Traffic Control in Work Zones. Indiana LTAP expresses thanks to ODOT for their permission to reprint this material.

High-Resolution Event-Based Data At Diamond Interchanges: Performance Measures And Optimizing Ring Displacement, Alexander M. Hainen, Amanda L. Stevens, Richard S. Freije, Christopher M. Day, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

Evaluation Of Structural Properties Of The Freeze–Thaw-Damaged Rc Beam Members By Nonlinear Finite-Element Analysis, Hiroshi Hayashida, Yasuhiko Sato, Tamon Ueda

International Conference on Durability of Concrete Structures

On RC beam members damaged by freeze–thaw cycles, the authors performed nonlinear finite-element analysis using distributed reinforcement and smeared cracking models, toward evaluating the structural properties of such RC beams. We then compared the analysis results to test results. The comparison found that the accuracy of analysis depends on the severity of concrete deterioration. It was clarified that the test values do not agree with the analysis values for RC beams that experience shear rigidity reduction from freezing damage to the compressive area or for RC beams that experience decreased rebar–concrete bonding strength from freezing damage to the tensile area. …

Kinetic Modeling Of Evolution Of 3 + 1:Resonance Enhanced Multiphoton Ionization Plasma In Argon At Low Pressures, Siva Sashank Tholeti, Mikhail N. Shneider, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

We present numerical kinetic modeling of generation and evolution of the plasma produced as a result of resonance enhanced multiphoton ionization (REMPI) in Argon gas. The particle-in-cell/Monte Carlo collision (PIC/MCC) simulations capture non-equilibrium effects in REMPI plasma expansion by considering the major collisional processes at the microscopic level: elastic scattering, electron impact ionization, ion charge exchange, and recombination and quenching for metastable excited atoms. The conditions in one-dimensional (1D) and two-dimensional (2D) formulations correspond to known experiments in Argon at a pressure of 5 Torr. The 1D PIC/MCC calculations are compared with the published results of local drift-diffusion model, obtained …

Experimental Measurements And Modeling Of Convective Heat Transfer In The Transitional Rarefied Regime, Andrew D. Strongrich, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

We present experimental measurements and numerical simulations of convective heat transferperformance in the transitional rarefied regime for an isolated rectangular beam geometry. Experiments were performed using single crystalline silicon beam elements having width-to-thickness aspect ratios of 8.5 and 17.4. Devices were enclosed in a vacuum chamber and heated resistively using a DC power supply. A range of pressures corresponding to Knudsen numbers between 0.096 and 43.2 in terms of device thickness were swept, adjusting applied power to maintain a constant temperature of 50 K above the ambient temperature. Both parasiticelectrical resistance associated with the hardware and radiative exchange with the …

Amplification And Reversal Of Knudsen Force By Thermoelectric Heating, William J. O'Neill, Mizuki Wada, Andrew D. Strongrich, Anthony Cofer, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

We show that the Knudsen thermal force generated by a thermally-induced flow over a heated beam near a colder wall could be amplified significantly by thermoelectric heating. Bidirectional actuation is achieved by switching the polarity of the thermoelectric device bias voltage. The measurements of the resulting thermal forces at different rarefaction regimes, realized by changing geometry and gas pressure, are done using torsional microbalance. The repulsive or attractive forces between a thermoelectrically heated or cooled plate and a substrate are shown to be up to an order of magnitude larger than for previously studied configurations and heating methods due to …

Structured Pairing In A First-Year Electrical And Computer Engineering Laboratory: The Effects On Student Retention, Attitudes, And Teamwork, Nicholas D. Fila, Michael C. Loui

School of Engineering Education Graduate Student Series

This paper describes a simple technique, structured pairing, for organizing student teams in engineering instructional laboratories. This technique was adapted from pair programming, which was previously found to improve student confidence, satisfaction, and retention in computer science. A study of structured pairing was implemented in a large required course for first-year students in electrical and computer engineering. Six laboratory sections implemented structured pairing, and the other seven laboratory sections operated in a traditional way (i.e., unstructured team interactions). Data were collected from a student survey, two focus groups, and course enrollment records. Structured pairing students reported significantly higher confidence in …

Research On Microscopic Pore Structure And Permeability Of Air-Entrained Fly–Ash Concrete Subjected To Freezing And Thawing Action, Zhuo Zhao, Dawang Li, Feng Xing, Ningxu Han, Dongwei Wang

International Conference on Durability of Concrete Structures

In this paper, rapid freezing and thawing test of air-entrained fly–ash concrete was carried out. Gas adsorption of concrete pores, mass loss, dynamic elastic modulus, and chloride diffusion coefficient of concrete after different freezing and thawing cycles was tested; scanning electron image was used to study the microscopic pore structure of the specimens. Results show that after certain freezing and thawing cycles, microscopic pores of the sample had a brittle failure, which results in sudden changes of cumulative desorption pore volume and cumulative desorption surface area obtained by Barrett, Joyner, and Halenda method. It was found that the variation of …

Using Acoustic Emission To Quantify Freeze–Thaw Damage Of Mortar Saturated With Nacl Solutions, Ye Qian, Yaghoob Farnam, Jason Weiss

International Conference on Durability of Concrete Structures

Mortar samples were saturated with NaCl solutions of various concentrations and subjected to freeze– thaw cycles. Passive and active acoustic emission (AE) testing was conducted. The freezing temperature of the NaCl solutions in mortar corresponded with the sudden observation of passive AE events. The acoustic energy and damage parameter were calculated to evaluate the extent of freeze–thaw damage. The influence of the NaCl solution concentration and whether the solution freezes on freeze–thaw damage are discussed.

Physical Model And Mesoscale Simulation Of Mortar And Concrete Deformations Under Freeze–Thaw Cycles, Fuyuan Gong, Evdon Sicat, Yi Wang, Tamon Ueda, Dawei Zhang

International Conference on Durability of Concrete Structures

The degradation of concrete material under multiple freeze–thaw cycles is an important issue for structures in cold and wet regions. This paper proposed a physical and mechanical model to explain the deformation behavior observed in previous experiments, from internal pressure calculation to mesoscale simulation, and for both closed and open freeze–thaw tests. Three kinds of internal pressures are considered in this study: hydraulic pressure due to ice volume expansion, crystallization pressure, and cryosuction pressure due to liquid–ice interface. The hydraulic pressure model combines Power’s model with poromechanical theories, which can well explain the reverse phenomenon (from expansion to contraction) observed …

Assessing Longitudinal Arterial Performance And Traffic Signal Retiming Outcomes, Steven M. Lavrenz, Christopher M. Day, W Benjamin Smith, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

A Compact Theory Of Magnetic Nerve Stimulation: Predicting How To Aim, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Background: A compact theory that predicts quantitatively when and where magnetic neurostimulation will occur is needed as a guide to therapy, ideally providing a single equation that defines the target volume of tissue excited by single or dual coils. Methods: A first-principles analysis of magnetic stimulation incorporating a simplified description of electromagnetic fields and a simplified cable theory of the axon yields a mathematical synthesis predicting how to aim. Results: Nerve stimulation produced by a single circular coil having one or more closely packed turns occurs in donut shaped volume of tissue beneath the coil. Axons spanning several millimeters are …