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- Electrical and Computer Engineering Faculty Research & Creative Works (9)
- Civil, Architectural and Environmental Engineering Faculty Research & Creative Works (6)
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Articles 1 - 18 of 18
Full-Text Articles in Engineering
Strong Circular Dichroism In Chiral Plasmonic Metasurfaces Optimized By Micro-Genetic Algorithm, Zhigang Li, Daniel Rosenmann, David A. Czaplewski, Xiaodong Yang, Jie Gao
Strong Circular Dichroism In Chiral Plasmonic Metasurfaces Optimized By Micro-Genetic Algorithm, Zhigang Li, Daniel Rosenmann, David A. Czaplewski, Xiaodong Yang, Jie Gao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Strong circular dichroism in absorption in the near-infrared wavelength range is realized by designing binary-pattern chiral plasmonic metasurfaces via the micro-genetic algorithm optimization method. The influence of geometric parameter modifications in the binary-pattern nanostructures on the circular dichroism performance is studied. The strong circular dichroism in absorption is attributed to the simultaneous excitation and field interference of the resonant modes with relative phase delay under linearly polarized incident light. This work provides a universal design method toward the on-demand properties of chiral metasurfaces, which paves the way for future applications in chemical and biological sensing, chiral imaging and spectroscopy.
Factorial Design Approach In Proportioning Prestressed Self-Compacting Concrete, Wu-Jian Long, Kamal Khayat, Guillaume Lemieux, Feng Xing, Wei-Lun Wang
Factorial Design Approach In Proportioning Prestressed Self-Compacting Concrete, Wu-Jian Long, Kamal Khayat, Guillaume Lemieux, Feng Xing, Wei-Lun Wang
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In order to model the effect of mixture parameters and material properties on the hardened properties of, prestressed self-compacting concrete (SCC), and also to investigate the extensions of the statistical models, a factorial design was employed to identify the relative significance of these primary parameters and their interactions in terms of the mechanical and visco-elastic properties of SCC. In addition to the 16 fractional factorial mixtures evaluated in the modeled region of -1 to +1, eight axial mixtures were prepared at extreme values of -2 and +2 with the other variables maintained at the central points. Four replicate central mixtures …
Asynchronous Advanced Encryption Standard Hardware With Random Noise Injection For Improved Side-Channel Attack Resistance, Siva Pavan Kumar Kotipalli, Yong-Bin Kim, Minsu Choi
Asynchronous Advanced Encryption Standard Hardware With Random Noise Injection For Improved Side-Channel Attack Resistance, Siva Pavan Kumar Kotipalli, Yong-Bin Kim, Minsu Choi
Electrical and Computer Engineering Faculty Research & Creative Works
This work presents the design, hardware implementation, and performance analysis of novel asynchronous AES (advanced encryption standard) Key Expander and Round Function, which offer increased side-channel attack (SCA) resistance. These designs are based on a delay-insensitive (DI) logic paradigm known as null convention logic (NCL), which supports useful properties for resisting SCAs including dual-rail encoding, clock-free operation, and monotonic transitions. Potential benefits include reduced and more uniform switching activities and reduced signal-to-noise (SNR) ratio. A novel method to further augment NCL AES hardware with random voltage scaling technique is also presented for additional security. Thereby, the proposed components leak significantly …
Development Of Bridge Girder Movement Criteria For Accelerated Bridge Construction, Genda Chen, Yi Bao
Development Of Bridge Girder Movement Criteria For Accelerated Bridge Construction, Genda Chen, Yi Bao
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
End diaphragms connect multiple girders to form a bridge superstructure system for effective resistance to earthquake loads. Concrete girder bridges that include end diaphragms consistently proved to perform well during previous earthquake events. However, whether concrete bridges without end diaphragms are definitively inadequate in seismic performance is yet to be answered. The 2010 Chile Earthquake indicated that properly designed bridge girders and their lateral movement stoppers (shear keys) may perform equally well with those with end diaphragms. In this report, a feasibility study on the design of girder bridges without end diaphragms is presented. This study is particularly significant in …
Parametric Analysis Of Resilient Modulus Modeling For Recycled Asphalt Pavement In Base Layer, Ehab Noureldin, Magdy Abdelrahman
Parametric Analysis Of Resilient Modulus Modeling For Recycled Asphalt Pavement In Base Layer, Ehab Noureldin, Magdy Abdelrahman
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The resilient modulus (MR) has been found to be the most important parameter in the Mechanistic-Empirical Pavement Design Guide (MEPDG) for the base layer. A literature review showed that the use of recycled asphalt pavement (RAP) in the base layer had many economic and structural benefits. The prediction of MR with the specific MEPDG model for the base layer mixed with RAP was found to be reliable for several field conditions. However, further studies of the MEPDG model are needed for an understanding of the physical meaning of each parameter in the model. The most important factor …
Variability Analysis Of Undrained Shear Strength For Reliability-Based Design, Site Onyejekwe, Xin Kang, Louis Ge, Richard Wesley Stephenson
Variability Analysis Of Undrained Shear Strength For Reliability-Based Design, Site Onyejekwe, Xin Kang, Louis Ge, Richard Wesley Stephenson
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Description of the Spatial Variation of Compositional and Mechanical Soil Parameters is Often Paramount in Site Characterization of Geotechnical Design and Analysis. the Values of the Parameters Themselves Largely Depend on In-Situ State Factors Which Are Related to Spatial Locations. Also, for Large-Scale Engineering Projects Such as Earth Dams or Highways, It is Generally Expected that Heterogeneous Site Characteristics Will Be Revealed by Investigations at Spatially Distant Locations. Currently, Most Reliability-Based Design Methods Are based on the Second-Moment Statistics (Mean and Variance). However, They Are Unable to Adequately Describe the Spatial Variation of Soil Properties. in This Paper, Spatial Correlation …
A System Design Approach For Unattended Solar Energy Harvesting Supply, Jonathan W. Kimball, Brian T. Kuhn, Robert S. Balog
A System Design Approach For Unattended Solar Energy Harvesting Supply, Jonathan W. Kimball, Brian T. Kuhn, Robert S. Balog
Electrical and Computer Engineering Faculty Research & Creative Works
Remote devices, such as sensors and communications devices, require continuously available power. In many applications, conventional approaches are too expensive, too large, or unreliable. For short-term needs, primary batteries may be used. However, they do not scale up well for long-term installations. Instead, energy harvesting methods must be used. Here, a system design approach is introduced that results in a highly reliable, highly available energy harvesting device for remote applications. First, a simulation method that uses climate data and target availability produces Pareto curves for energy storage and generation. This step determines the energy storage requirement in watt-hours and the …
Mechanistic-Empirical Modeling In Network-Level Pavement Management, Scott Schram, Magdy Abdelrahman
Mechanistic-Empirical Modeling In Network-Level Pavement Management, Scott Schram, Magdy Abdelrahman
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Researchers and practitioners have long recognized the advantages of mechanistic modeling. As agencies implement the Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures [referred to as the Mechanistic-Empirical Pavement Design Guide (MEPDG)] in the local project-level pavement management system (PMS), its potential as a planning tool in network-level analyses remains unrecognized. A unique, large-scale application of MEPDG is presented. The Nebraska Department of Roads uses a decision tree that systematically screens and identifies candidates for entry into a multiyear optimization program. The process uses linear deterioration rates that have been shown to provide an R2 value as …
Characterization Of Serial Links At 5.5gbps On Fr4 Backplanes, Vittorio Ricchiuti, Antonio Orlandi, James L. Drewniak, Francesco De Paulis
Characterization Of Serial Links At 5.5gbps On Fr4 Backplanes, Vittorio Ricchiuti, Antonio Orlandi, James L. Drewniak, Francesco De Paulis
Electrical and Computer Engineering Faculty Research & Creative Works
Nowdays the fast and increased demand for bandwidth in the telecommunication world translates into the design of complex boards exchanging data at high bit rate in reduced design cycle. Sometimes it is impossible to spent time in setting pre-layout simulations, because they are not compatible with the design time schedule. In this scenario it is better to design the boards using experience and then make simulations in conjunction with measurements, using customized numerical tools which don't need complex models.
Differential Evolution Particle Swarm Optimization For Digital Filter Design, Bipul Luitel, Ganesh K. Venayagamoorthy
Differential Evolution Particle Swarm Optimization For Digital Filter Design, Bipul Luitel, Ganesh K. Venayagamoorthy
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, swarm and evolutionary algorithms have been applied for the design of digital filters. Particle swarm optimization (PSO) and differential evolution particle swarm optimization (DEPSO) have been used here for the design of linear phase finite impulse response (FIR) filters. Two different fitness functions have been studied and experimented, each having its own significance. The first study considers a fitness function based on the passband and stopband ripple, while the second study considers a fitness function based on the mean squared error between the actual and the ideal filter response. DEPSO seems to be promising tool for FIR …
Systems Approach For Estimating Field Moisture Content, Thomas M. Petry, Yuh-Puu Han, David Newton Richardson
Systems Approach For Estimating Field Moisture Content, Thomas M. Petry, Yuh-Puu Han, David Newton Richardson
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper describes a software tool developed for estimation of the field moisture content of subgrade materials. Subgrade behavior is directly related to its moisture content. Unfortunately, some approaches of estimating field moisture content are too complex to be used in routine design. In this paper, the authors attempt to provide an approach that is easy to use. The software presented here was developed using expert system approaches. It is capable of analyzing data entered by the users, and providing estimations to meet different scenarios. The information entered by the user is first examined for its reasonableness and accuracy. Then, …
Analysis And Design Of Switched Capacitor Converters, Jonathan W. Kimball, Philip T. Krein
Analysis And Design Of Switched Capacitor Converters, Jonathan W. Kimball, Philip T. Krein
Electrical and Computer Engineering Faculty Research & Creative Works
Switched capacitor converters have become more common in recent years. Crucial to understanding the maximum power throughput and efficiency is a model of the converter's equivalent resistance. A new form for equivalent resistance is derived and discussed in a design context. Quasi-resonant operation is also explored and compared to non-resonant operation. Several capacitor technologies are evaluated and compared.
Retaining Walls Under Seismic Loading, Vijay K. Puri, Shamsher Prakash, Retno Widanarti
Retaining Walls Under Seismic Loading, Vijay K. Puri, Shamsher Prakash, Retno Widanarti
International Conference on Case Histories in Geotechnical Engineering
The design of retaining walls in seismic areas poses a complex problem. The traditional design approach usually consists of calculation of a factor of safety against sliding, overturning and bearing capacity failure. This is generally enough for static loads. During seismic loading, the retaining walls tend to get displaced from their original position. The performance of quay walls during the past earthquakes emphasizes this fact. For safe design of retaining walls in seismic areas, the calculation of static and dynamic earth pressure behind the retaining walls is the first requirement. Realistic calculation of displacement of the retaining wall is an …
A Simple, Robust, And On-Site Microwave Technique For Determining Water-To-Cement Ratio (W/C) Of Fresh Portland Cement-Based Materials, K. Mubarak, Karl Joseph Bois, R. Zoughi
A Simple, Robust, And On-Site Microwave Technique For Determining Water-To-Cement Ratio (W/C) Of Fresh Portland Cement-Based Materials, K. Mubarak, Karl Joseph Bois, R. Zoughi
Electrical and Computer Engineering Faculty Research & Creative Works
Inspection and evaluation of cement-based materials such as concrete is of great interest to the construction industry. In particular, real-time and on-site evaluation of water-to-cement ratio (w/c) is an important practical issue, since the compressive strength of a concrete structure is significantly influenced by its w/c. Currently, there is no single real-time, on-site, relatively in-expensive, easy-to-implement, and operator friendly technique for evaluating this parameter. Microwave nondestructive testing and evaluation techniques have shown great promise when used for inspection and evaluation of the properties of cement-based materials. In this paper, the optimal design of a monopole antenna probe used to evaluate …
Dc Power Bus Modeling In High-Speed Digital Designs Including Conductor And Dielectric Losses, Jun Fan, Hao Shi, James L. Knighten, James L. Drewniak
Dc Power Bus Modeling In High-Speed Digital Designs Including Conductor And Dielectric Losses, Jun Fan, Hao Shi, James L. Knighten, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
Power bus design is a critical aspect in high-speed digital circuit designs. A circuit extraction approach based on a mixed-potential integral equation formulation is presented herein to model arbitrary multilayer power bus structures including vertical discontinuities associated with surface mount (SMT) decoupling capacitor interconnects. Both conductor and dielectric losses are incorporated, and included into the first principles formulation. The agreement of modeling and measurements demonstrates its effectiveness and utilization in power bus designs.
An Expert System Approach To Emc Modeling, Todd H. Hubing, James L. Drewniak, Thomas Van Doren, Navin Kashyap
An Expert System Approach To Emc Modeling, Todd H. Hubing, James L. Drewniak, Thomas Van Doren, Navin Kashyap
Electrical and Computer Engineering Faculty Research & Creative Works
Existing computer software for EMC analysis can be divided into three categories. Analytical modeling codes employ closed form expressions to solve problems of general interest to EMC engineers or circuit designers. Numerical modeling codes use numerical techniques to solve Maxwell's equations subject to specific boundary conditions. EMC rule checkers search a design for features that violate basic EMC design guidelines. This paper outlines the relative advantages and limitations of each of these three approaches and describes an expert system EMC modeling approach. The new approach combines analytical models, numerical models, and EMC rule-checking in order to evaluate designs in much …
Photovoltaic-Powered Water Pumping-Design, And Implementation: Case Studies In Wyoming, Badrul H. Chowdhury, S. Ula, K. Stokes
Photovoltaic-Powered Water Pumping-Design, And Implementation: Case Studies In Wyoming, Badrul H. Chowdhury, S. Ula, K. Stokes
Electrical and Computer Engineering Faculty Research & Creative Works
A photovoltaic-powered water pumping project comprising of several rural electric cooperatives and their customers is described in detail. A number of remote water pumping installations in the state of Wyoming, USA, are currently operating as a result of this project. The design, installation and performance monitoring of these systems are discussed. In general, it can be stated that PV-powered water pumping in this state has been a cost-effective alternative to distribution line extension or other conventional means of water pumping. Customer satisfaction, in terms of functional adequacy and low maintenance requirements of these systems, is high. The benefit for the …
Design Considerations For 1-3 Composites Used In Transducers For Medical Ultrasonic Imaging, Wayne Huebner, Kuiming Liang, Clyde G. Oakley
Design Considerations For 1-3 Composites Used In Transducers For Medical Ultrasonic Imaging, Wayne Huebner, Kuiming Liang, Clyde G. Oakley
Materials Science and Engineering Faculty Research & Creative Works
Ceramic polymer piezoelectric composites with 1-3 connectivity have become an important tool in the design and manufacture of thickness-mode transducers for medical diagnostic ultrasonic imaging. The authors compare annular array transducers made from ceramics alone to those made with these composites to demonstrate the advantages of composites. They examine some of the trade-offs involved in optimizing composite designs for this application. The effects of varying Young's modulus and Poisson's ratio of the polymer phase on the coupling coefficient and high-frequency lateral resonances of the composite are presented