Engineering Commons^™

Hysteresis And Delta Modulation Control Of Converters Using Sensorless Current Mode, Jonathan W. Kimball, Philip T. Krein, Yongxiang Chen

Electrical and Computer Engineering Faculty Research & Creative Works

Sensorless current mode (SCM) is a control formulation for dc-dc converters that results in voltage-source characteristics, excellent open-loop tracking, and near-ideal source rejection. Hysteresis and delta modulation are well-known, easy-to-construct large-signal methods for switched systems. Combining either large-signal method with SCM creates a controller that is simpler and more robust than a pulse-width modulation (PWM) based controller. The small-signal advantages of PWM-based SCM are retained and expanded to include converter response to large-signal disturbances. These approaches can be used with any converter topology over a broad range of operating conditions. In the present work, hysteresis and delta modulation SCM controllers …

An Approach To Active Sensor Imaging, Askin Demirkol, Levent Acar, Robert S. Woodley

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an alternative Target Density Function (TDF) is proposed to image the radar targets in a dense target environment. It is obtained by considering a novel range and scanning angle plane different from the conventional methods. An alternative method is briefly proposed for smoothing the target density function by taking advantage of Walsh functions. Although the imaging is obtained via the phased array radars, the problem associated with beamforming in linear phased array radar system is bypassed in this new algorithm.

A Radar Sensing Algorithm By Gabor Theory, Askin Demirkol, Levent Acar, Robert S. Woodley

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an alternative Target Density Function( TDF) is proposed for narrowband radar model. This is achieved by estimating a new target density function by Gabor theory. It is shown how Gabor transform can be used to obtaining wideband target density function by transmitting a waveform which is a kernel for this transform. The windowing characteristics of this theory is plausible to reaching an accurate result. The presented wideband target density function is developed in a various manner different from the conventional methods.

Incorporating Solid Mechanics Into Biomedical And Life Sciences, Kai-Tak Wan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Integrating and interfacing solid mechanics and life sciences is challenging, but, with effort, the two disciplines can complement one another. This paper describes work ongoing at the Mechanical and Aerospace Engineering Department of the University of Missouri at Rolla on cellular biomechanics and mechanical characterization of single cells. Also discussed is the study of tissue biomechanics in understanding the mechanical aspects of lens accommodation in human vision.

An Efficient Discontinuous-Mode Model Of A Switch Pole, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

Simulating switching power supplies presents many challenges. A variety of switch pole models is available, from the physics-based to the behavioral. The present work develops and demonstrates a behavioral model that works well in discontinuous mode. The new model eliminates the extremely fast time constants normally associated with switches in a high impedance state. Simulation time is improved and fixed-time-step algorithms are now stable with reasonable step size.

Cost-Driven Repair Of A Nanowire Crossbar Architecture, Yadunandana Yellambalase, Shanrui Zhang, Minsu Choi, Nohpill Park, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

The recent development of nanoscale materials and assembly techniques has resulting in the manufacturing of high-density computational systems. These systems consist of nanometer-scale elements and are likely to have many manufacturing imperfections (defects); thus, defect-tolerance is considered as one of the most some algorithms for repairing defective crosspoints in a nanoscale crossbar architecture; furthermore we estimate the efficiency and cost-effectiveness of each algorithm. Also, for a given design and manufacturing environment, we propose a cost-driven method to find a balanced solution by which figures of merit such as area, repair time and reconfiguration cost can be taken into account. Probabilistic …

Neural Network Based Decentralized Excitation Control Of Large Scale Power Systems, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch, David A. Cartes, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a neural network (NN) based decentralized excitation controller design for large scale power systems. The proposed controller design considers not only the dynamics of generators but also the algebraic constraints of the power flow equations. The control signals are calculated using only local signals. The transient stability and the coordination of the subsystem controllers can be guaranteed. NNs are used to approximate the unknown/imprecise dynamics of the local power system and the interconnections. All signals in the closed loop system are guaranteed to be uniformly ultimately bounded (UUB). Simulation results with a 3-machine power system demonstrate the …

Compact Autonomous Explosive-Driven Pulsed Power System Based On A Capacitive Energy Storage Charged By A High-Voltage Shock-Wave Ferromagnetic Generator, S. I. Shkuratov, E. F. Talantsev, Jason Baird, Larry L. Altgilbers, A. H. Stults

Mining Engineering Faculty Research & Creative Works

A new concept for constructing compact autonomous pulsed power systems is presented. This concept utilizes a high-voltage explosive-driven shock-wave ferromagnetic generator (FMG) as a charging source for capacitive energy storage. It has been experimentally demonstrated that miniature FMGs (22-25 cm³ in size and 84-95 g in mass) developed for these experiments can be successfully used to charge capacitor banks. The FMGs, containing Nd₂Fe₁₄B energy-carrying elements, provided pulsed powers of 35-45 kW in times ranging from 10 to 15 µs. A methodology was developed for digital simulation of the operation of the transverse FMG. Experimental results that were obtained are in …

Direct Strength Method (Dsm) Design Guide, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The following Design Guide has been developed under the direction of the American Iron and Steel Institute Committee on Specifications for the Design of Cold-Formed Steel Structural Members. The development of the Guide was sponsored by the American Iron and Steel Institute. The AISI Committee on Specifications wishes to acknowledge and expresses gratitude to Dr. Benjamin Schafer of Johns Hopkins University who was the author of this Guide.

With anticipated improvements in understanding of the behavior of cold-formed steel and the continuing development of new technology, this material might become dated. It is possible that AISI will attempt to produce …

Leadership In Student Distance Education Teams, Leroy Cox, Susan L. Murray, David Spurlock

Engineering Management and Systems Engineering Faculty Research & Creative Works

Interactive video technology has become a widely used medium for education. A prominent implementation of this technology, interactive distance learning, involves groups of students at local and remote sites connected by audio and video teleconferencing. This approach has made the task of delivering vital undergraduate and graduate engineering courses to distributed audiences much easier. As this approach has permeated more curricula, distance education instructors have increasingly assigned projects that require distance learners to work together as an element of the final course grade. This trend presents an interesting opportunity for researchers to understand the nature of interactions among course participants …

Service Learning At Cincinnati: Researching Water Treatment For Emerging Economies, Sarah I. Pumphrey, Anna Hoessle, Daniel B. Oerther

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Of the nearly six billion human inhabitants of planet earth, nearly two thirds lack access to sufficient quantities of potable water and access to basic sanitation. These appalling conditions result in the deaths of millions of children each year from preventable waterborne diarrheal disease. At the University of Cincinnati, two female graduate students have undertaken MS degrees with the specific objective of performing service learning where the research focus of their respective degrees is validating and deploying appropriate technology for water quality treatment in developing countries. This presentation will highlight the results of these research projects as well as the …

A Time-To-First Spike Cmos Image Sensor With Coarse Temporal Sampling, Qiang Luo, John G. Harris, Zhiliang J. Chen

Electrical and Computer Engineering Faculty Research & Creative Works

Conventional voltage-based CMOS image sensors inherently have a dynamic range of about 60 dB. To extend the dynamic range, a two-degree of freedom time-based CMOS image sensor is proposed. Instead of reading analog voltages off chip, a time representation is used to record when the photodetector voltage passes a timing-varying threshold. The time measurements are combined with the reference voltage waveform to reconstruct the image. Experimental results on a prototype 32 x 32-pixel array CMOS image sensor verify that the two-degree of freedom sampling technique is feasible for ultra-wide dynamic range imaging. A measured 115 dB dynamic range at 30 …

Inertia And Memory In Ambiguous Visual Perception, J. B. Gao, V. A. Billock, I. Merk, W. W. Tung, K. D. White, J. G. Harris, V. P. Roychowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Perceptual multistability during ambiguous visual perception is an important clue to neural dynamics. We examined perceptual switching during ambiguous depth perception using a Necker cube stimulus, and also during binocular rivalry. Analysis of perceptual switching time series using variance-sample size analysis, spectral analysis and time series shuffling shows that switching times behave as a 1/f noise and possess very long-range correlations. The long memory feature contrasts sharply with the traditional satiation models of multistability, where the memory is not incorporated, as well as with recently published models of multistability and neural processing, where memory is excluded. On the other hand, …

A Field Reconstruction Method For Optimal Excitation Of Permanent Magnet Synchronous Machines, Weidong Zhu, Babak Fahimi, Steve Pekarek

Electrical and Computer Engineering Faculty Research & Creative Works

Vibration caused by torque ripple and radial force harmonics is a concern in many applications of permanent magnet synchronous machines (PMSMs). Alternative methods of machine design and/or stator excitation to minimize torque ripple have received considerable attention in recent years. Comparatively, methods to minimize radial force harmonics have received less attention. in this paper, a field reconstruction (FR) method is derived that provides a designer with the capability to rapidly determine the radial and tangential components of force under arbitrary stator excitation. using the field reconstruction method, stator current waveforms that minimize the ripple of both torque and radial force …

Nanomanipulation Using Atomic Force Microscope With Drift Compensation, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an atomic force microscope (AFM) based force controller to push nanoparticles on the substrates since it is tedious for human. A block phase correlation-based algorithm is embedded into the controller for compensating the thermal drift during nanomanipulation. Further, a neural network (NN) is employed to approximate the unknown nanoparticle and substrate contact dynamics including the roughness effects. Using the NN-based adaptive force controller the task of pushing nanoparticles is demonstrated. Finally, using the Lyapunov-based stability analysis, the uniform ultimately boundedness (UUB) of the closed-loop signals is demonstrated

Adaptive Neural Network Control And Wireless Sensor Network Based Localization For Uav Formation, H. Wu, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

We consider a team of unmanned aerial vehicles (UAV's) equipped with sensors and motes for wireless communication for the task of navigating to a desired location in a formation. First a neural network (NN)-based control scheme is presented that allows the UAVs to track a desired position and orientation with reference to the neighboring UAVs or obstacles in the environment. Second, we discuss a graph theory-based scheme for discovery, localization and cooperative control. The purpose of the NN cooperative controller is to achieve and maintain the desired formation shape in the presence of unmodeled dynamics and bounded unknown disturbances. Numerical …

Calibration Of The Corelok Method For Determination Of Missouri Aggregate Specific Gravities, David Newton Richardson, S. M. Lusher

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Specific gravity and absorption are fundamental aggregate properties needed for hot-mix asphalt (HMA) and Portland cement concrete (PCC) mix design and/or volumetric determinations. MoDOT utilizes the American Association of State Highway and Transportation Officials (AASHTO) standard test methods T 84 (for fine aggregates) and T 85 (for coarse aggregates) to determine these important properties. Criticisms of these procedures are the subjective nature of determining when the aggregates have reached the saturated, surface-dry (SSD) condition (especially T 84) and the substantial amount of time needed to complete the tests. The CoreLok method addresses these criticisms in that it is an objective …

The Antibacterial Effects Of Zinc Ion Migration From Zinc-Based Glass Polyalkenoate Cements, D. Boyd, H. Li, D. A. Tanner, Mark R. Towler, J. G. Wall

Chemical and Biochemical Engineering Faculty Research & Creative Works

Zinc-based glass polyalkenoate cements have been synthesised and their potential use in orthopaedic applications investigated. Zinc ions were released from the materials in a rapid burst over the first 24 h after synthesis, with the release rate falling below detectable levels after 7 days. Cement-implanted bone samples were prepared, and the released zinc was shown, using energy dispersive X-ray analysis, to penetrate from the cement into the adjacent bone by up to 40 μm. Finally, the cements exhibited antibacterial activity against Streptococcus mutans and Actinomyces viscosus that reflected the pattern of zinc release, with the inhibition of growth greatest shortly …

Methane Production In A 100-L Upflow Bioreactor By Anaerobic Digestion Of Farm Waste, Abhijeet P. Borole, K. Thomas Klasson, Whitney Ridenour, Justin Holland, Khursheed Karim, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Manure Waste from Dairy Farms Has Been Used for Methane Production for Decades, However, Problems Such as Digester Failure Are Routine. the Problem Has Been Investigated in Small Scale (1-2 L) Digesters in the Laboratory; However, Very Little Scale-Up to Intermediate Scales Are Available. We Report Production of Methane in a 100-L Digester and the Results of an Investigation into the Effect of Partial Mixing Induced by Gas Upflow/recirculation in the Digester. the Digester Was Operated for a Period of About 70 D (With 16-D Hydraulic Retention Time) with and Without the Mixing Induced by Gas Recirculation through an Internal …

An Engineering Research Experience For Teachers: Implementation And Assessment, Anant R. Kukreti, Patricia Mcnerney, Suzanne Wegener Soled, Kelly Josephine Obarski, Mingming Lu, Richard Miller, Daniel B. Oerther, Heng Wei, Thaddeus W. Fowler

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Disseminating Molecular Biology For Environmental Engineers With Nsf Ccli Support, Daniel B. Oerther, Catherine V. Maltbie, Baikun Li, Jin Li, Amy Pruden, Peter George Stroot

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

For the past five years, more than fifty undergraduate and graduate students at the University of Cincinnati have participated in a term-length course, CEE69 Molecular Biology for Environmental Systems. Using a self-paced approach, teams of students complete laboratory exercises to answer open ended questions about the composition of the microbiological community in an environmental sample. With the financial support of a Adaptation and Implementation (A&I) track grant from the NSF Course, Curriculum, and Laboratory Improvement program the course from Cincinnati is being taught at four partner institutions. This paper highlights the unique challenges of adapting the existing course to other …

Using Phosphorus Recovery From Wastewater As A Context For Teaching Sustainable Development With Usepa P3 Support, Daniel B. Oerther, Cinnamon Carlarne, Eric Maurer, Regina Lamendella, Sarah I. Pumphrey

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Phosphorus is an essential element required for agriculture. Current practices include "one-way" use of phosphorus: that is mining; production of fertilizer; land application; and ultimately loss to aquatic sediments. Once in the aquatic environment, phosphorus stimulates eutrophication resulting in the "death" of water bodies. With financial support from a People, Prosperity, and Planet program grant of the U.S. Environmental Protection Agency, an interdisciplinary team of faculty at the University of Cincinnati used phosphorus recovery from sewage and re-utilization as a struvite fertilizer as the context for a year-long course of study integrating graduate and undergraduate students in Environmental Engineering and …

Cerium-Based Spontaneous Coating Process For Corrosion Protection Of Aluminum Alloys, James O. Stoffer, Thomas J. O'Keefe, Matthew O'Keefe, Eric L. Morris, Scott A. Hayes, Paul Yu, Alex Williams, Berny F. Rivera Vasquez, Xuan Lin

Chemistry Faculty Research & Creative Works

A cerium-based coating for corrosion resistance is applied by exposing a cleaned aluminum-based component to a corrosion-inhibiting cerium solution containing cerium ions in the presence of an oxidizing agent. The coating deposits spontaneously without an external source of electrons.

Thermal Analysis Of Adsorbed Poly(Methyl Methacrylate) On Silica, Frank D. Blum, Erin N. Young, Gregory Smith, Oliver C. Sitton

Chemistry Faculty Research & Creative Works

Modulated differential scanning calorimetry has been used to quantify the glass transitions of small, adsorbed amounts of poly (methyl methacrylate) (PMMA) on silica. While a relatively narrow, single glass transition was found for bulk PMMA, broader two-component transitions were found for the adsorbed polymer. a two-state model based on loosely bound polymer (glass transition similar to bulk) and more tightly bound polymer (glass transition centered around 156°C) was used to interpret the thermograms. on the basis of this model, the amount of tightly bound polymer was found to be approximately 1.3 mg/m 2, corresponding to a 1.1 nm thick layer. …

Simulations Of A New Continuous Steelmaking Process, Jorg Annie Peter, Kent D. Peaslee, D. G. C. Robertson

Materials Science and Engineering Faculty Research & Creative Works

A new continuous steelmaking process has been designed in an effort to reduce meltshop costs and increase productivity beyond the possibilities of current EAF-LMF-CC meltshops. This paper discusses possible operational performance based on industrially-verified kinetic, thermodynamic, and heat-transfer models. Dynamic simulations predict variations in steel chemistry and temperature, resulting from steel treatment and upsets. Savings in costs are projected because of increased metallic yield, lower energy requirements, more efficient use of deoxidants and alloys, fewer man-hours per ton, and decreased capital investment.

An Efficient Approach For Power Delivery Network Design With Closed-Form Expressions For Parasitic Interconnect Inductances, Chen Wang, Jingkun Mao, Giuseppe Selli, Shaofeng Luan, Lin Zhang, Jun Fan, David Pommerenke, Richard E. Dubroff, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Investigation of a dc power delivery network, consisting of a multilayer PCB using area fills for power and return, involves the distributed behavior of the power/ground planes and the parasitics associated with the lumped components mounted on it. Full-wave methods are often employed to study the power integrity problem. While full-wave methods can be accurate, they are time and memory consuming. The cavity model of a rectangular structure has previously been employed to efficiently analyze the simultaneous switching noise (SSN) in the power distribution network. However, a large number of modes in the cavity model are needed to accurately simulate …

Evaluation Of Alternative Evolutionary Programming Techniques For Optimization Of An Automotive Alternator, Andreas C. Koenig, Joshua M. Williams, Steven D. Pekarek

Electrical and Computer Engineering Faculty Research & Creative Works

One of the primary design requirements of automotive generation systems is maximizing power density subject to the constraint of minimizing the overall system cost. However, with the progress made in the reduction of automotive drive train noise, the torque ripple of the generator has been found to be a dominant noise source under idle conditions at high electrical loads. Thus, an added design constraint is the minimization of the torque ripple produced by the machine. in order to evaluate alternative machine designs (and select an optimal), numerical tools are typically applied. in this research, a focus is placed on the …

Obstacle Avoidance In Collective Robotic Search Using Particle Swarm Optimization, Lisa L. Smith, Ganesh K. Venayagamoorthy, Phillip G. Holloway

Electrical and Computer Engineering Faculty Research & Creative Works

Particle Swarm Optimization (PSO) has been demonstrated to be a useful technique in target search applications such as Collective Robotic Search (CRS). A group of unmanned mobile robots are able to locate a specified target in a high risk environment with extreme efficiency when driven by an optimized PSO algorithm. This paper presents an algorithm for obstacle avoidance with the PSO approach applied to navigate robots in collective search applications. Obstacles represented by basic geometric shapes to simulate perilous ground terrain are introduced to the search area. Results are presented to show that PSO algorithm based CRS is able to …

Comparison Of Pso And Ga For K-Node Set Reliability Optimization Of A Distributed System, G. A. Bakare, I. N. Chiroma, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Particle Swarm Optimization (PSO), as a novel evolutionary computing technique, has succeeded in many continuous problems, but quite a little research on discrete problem especially combinatorial optimization problem has been reported. In this paper, a discrete PSO algorithm is proposed to solve a typical combinatorial optimization problem: K-Node Set Reliability (KNR) optimization of a distributed computing system (DCS) which is a well-known NP-hard problem is presented. It computes the reliability of a subset of network nodes of a DCS such that the reliability is maximized and specified capacity constraint is satisfied. The feasibility of the proposed algorithm is demonstrated on …

Modeling Of The Ic's Switching Currents On The Power Bus Of A High Speed Digital Board, Mauro Lai, James L. Drewniak, Vittorio Ricchiuti, Antonio Orlandi, Giulio Antonini

Electrical and Computer Engineering Faculty Research & Creative Works

When the performances of the electronic technology increase (higher frequencies, more power, lover power supply, faster transistors, reduced chip dimensions), designing electronic equipment becomes more challenging for the electronic engineers. Signal and power integrity on board become of paramount importance. One of the main causes of board malfunctions and electromagnetic radiation is the simultaneous switching noise (SSN) due to the integrated circuits soldered on the board. The paper proposes two simple procedures to model the SSN, so to evaluate its effects in any point of the board.