Engineering Commons^™

The Systemic Correlation Between Mental Models And Sustainable Design: Implications For Engineering Educators, Linda Vanasupa, Roger Burton, Jonathan Stolk, Julie B. Zimmerman, Larry J. Leifer, Paul T. Anastas

Materials Engineering

Many studies have illuminated our understanding of the kinds of competencies and behaviors exhibited by effective designers. Against the backdrop of global challenges made more urgent by unintentional negative impacts of engineered products and systems, however, we are left to deduce that our ways of educating engineering designers is fundamentally flawed. We assert that one can trace the cause of our collective, unintended negative consequences to the mental models of reality that we consciously or unconsciously carry. In this paper, we present the case for developing awareness and facility with mental models. We also suggest an alternate mental model as …

Facility Power Usage Modeling And Short Term Prediction With Artificial Neural Networks, Sunny Wan, Xiao-Hua Yu

Electrical Engineering

Residential and commercial buildings accounted for about 68% of the total U.S. electricity consumption in 2002. Improving the energy efficiency of buildings can save energy, reduce cost, and protect the global environment. In this research, artificial neural network is employed to model and predict the facility power usage of campus buildings. The prediction is based on the building power usage history and weather conditions such as temperature, humidity, wind speed, etc. Different neural network configurations are discussed; satisfactory computer simulation results are obtained and presented.

Nitrous Oxide Cooling In Hybrid Rocket Nozzles, Patrick Lemieux

Mechanical Engineering

The Department of Mechanical Engineering at the California Polytechnic State University, San Luis Obispo, has developed an innovative program of experimental research and development on hybrid rocket motors (where the fuel and the oxidizer are in different phases prior to combustion). One project currently underway involves the development of aerospike nozzles for such motors. These nozzles, however, are even more susceptible to throat ablation than regular converging diverging nozzles, due the nature of their flow expansion mechanism. This paper presents the result of a recent development project focused on reducing throat ablation in hybrid rocket motor nozzles. Although the method …

Beneficial Reuse Of Corrugated Board In Slurry Applications, James L. Hanson, Nazli Yesiller, Jagjit Singh, Greg M. Stone, Adam Stephens

Civil and Environmental Engineering

Use of virgin and post-consumer corrugated board as a replacement for bentonite in slurry mixes was investigated. The effectiveness of the slurry mixes was assessed using typical tests including Marsh funnel viscosity, density, and filtrate loss. Filter cake permeability was also determined. Corrugated board was fiberized for the test program. Test results indicated that corrugated board could be used to replace 9 to 27% (0.5 to 1.5% corrugate content) of bentonite in slurry mixes with a total solids content of 5.5%. Slurry applications provide a new and viable beneficial reuse alternative for paper/paperboard products, which constitute the largest weight and …

Genetic Programming To Investigate Design Parameters Contributing To Crash Occurence On Urban Arterials, Abhishek Das, Mohamed Abdel-Aty, Anurag Pande

Civil and Environmental Engineering

Nonlinear models were developed to estimate crash frequency on urban arterials with partial access control. These multilane arterials consist of midblock segments joined by signalized and unsignalized intersections (or access points). Crashes included in the analysis are of three major types: rear-end, angle, and head-on. Each crash type is further sorted into mutually exclusive categories on the basis of the roadway element responsible for the crashes: midblock segment, signalized intersection, and access point. Genetic programming (GP) is adopted for predicting crash frequency. GP, which is primarily based on genetic algorithms, uses the concept of evolution to develop models through the …

Mixi Thruster Tungsten And Thoriated Tungsten Testing, Jesse R. Miller

Aerospace Engineering

The purpose of this project is to build and evaluate a tungsten filament cathode for the 3-cm Miniature Xenon Ion (MiXI) thruster. The filament is to be used for future tests within the CP 3-cm MiXI and thoriated tungsten is to be examined as a possible alternative. No testing of these filaments was conducted, but the preparatory work has been conducted for future testing.

Where Is All That Water Going?, Charles M. Burt

BioResource and Agricultural Engineering

Some have proposed to conserve 4-6 Million AF/yr in Agriculture with pragmatic, economical measures. All we need to do is find the inefficiencies. Then we'll get rid of them.

Spontaneous Periodic Deformations In Nonchiral Planar-Aligned Bimesogens With A Nematic-Nematic Transition And A Negative Elastic Constant, V. P. Panov, J. K. Vij, Yuri Panarin, A. Kohlmeier, M. G. Tamba, R. A. Lewis, G. H. Mehl

Articles

Hydrocarbon linked mesogenic dimers are found to exhibit an additional nematic phase below the conventional uniaxial nematic phase as confirmed by x-ray diffraction. The phase produces unusual periodic stripe domains in planar cells. The stripes are found to be parallel to the rubbing direction (in rubbed cells) with a well-defined period equal to double the cell gap. The stripes appear without external electromagnetic field, temperature or thickness gradients, rubbing or hybrid alignment treatments. Simple modeling proposes a negative sign for at least one of the two elastic constants: splay and twist, as a necessary condition for the observed pattern.

A Comparative Study Of Capacitor Voltage Balancing Techniques For Flying Capacitor Multi-Level Power Electronic Converters, Vennela Yadhati

Masters Theses

"With the advent of multilevel converters for high power applications in industry, a need to develop simpler topologies and control techniques has arisen. The flying capacitor multilevel inverter (FCMLI) is one such topology which is gaining popularity in recent years with many advantages such as extra ride-through capabilities because of the capacitor storage, redundancy in switching states, low common mode voltage ratio, improved power quality, etc. In this thesis, different basic multilevel converter topologies and their advantages and applications are discussed. The thesis mainly focuses on single-phase five-level FCMLI topology. Different control techniques for capacitor voltage regulation like staircase modulation, …

Numerical Investigation Of Aeroelastic Mode Distribution For Aircraft Wing Model In Subsonic Air Flow, Marianna A. Shubov, Stephen B. Wineberg, Robert Holt

Mathematics & Statistics

In this paper, the numerical results on two problems originated in aircraft wing modeling have been presented. The first problem is concerned with the approximation to the set of the aeroelastic modes, which are the eigenvalues of a certain boundary-value problem. The affirmative answer is given to the following question: can the leading asymptotical terms in the analytical formulas be used as reasonably accurate description of the aeroelastic modes? The positive answer means that these leading terms can be used by engineers for practical calculations. The second problem is concerned with the flutter phenomena in aircraft wings in a subsonic, …

Overnight Atmospheric Transport And Chemical Processing Of Photochemically Aged Houston Urban And Petrochemical Industrial Plume, Rahul A. Zaveri, Paul B. Voss, Carl M. Berkowitz, Edward Fortner, Jun Zheng, Renyi Zhang, Ralph J. Valente, Roger L. Tanner, Daniel Holcomb, Thomas P. Hartley, Leslie Baran

Engineering: Faculty Publications

Overnight atmospheric transport and chemical evolution of photochemically aged Houston urban and petrochemical industrial plume were investigated in July 2005. We report here on the 26 July episode in which the aged plume was tagged 1.5 h before sunset with a pair of free-floating controlled meteorological balloons, which guided quasi-Lagrangian aircraft sampling in the plume as it was advected 300 km to the north over 8 h. The aged plume around sunset was well mixed within a 1600 m residual layer, and was characterized by enhanced levels of aerosol, O3, CO, olefins, acetaldehyde, total odd nitrogen compounds (NOy), and relatively …

Drafting A Blueprint For Educating Tomorrow's Engineers Today, Beth Mcginnis-Cavanaugh, Glenn Ellis, Diana Fiumefreddo

Engineering: Faculty Publications

No abstract provided.

Developing A Cloud Integrated Life Cycle Costing Analysis Model Through Bim, Alan Redmond, Alan V. Hore, Roger West

Conference papers

Advancing interoperability between design team applications has been a major challenge for advocates of open standards. The buildingSmart alliance and Open Geospatial Consortium Inc in the U.S. have developed and implemented an Architecture, Engineering, Construction, Owner Operator, Phase 1 Testbed that streamlines communications between parties at the conceptual design phase to establish an early understanding of the tradeoffs between construction cost and energy efficiency. The results of this Testbed combined with an on-going collaborative R&D project ‘Inpro’ co-funded by the European Commission to identify business and legal issues of Building Information Modeling in construction were used as theoretical propositions underlying …

Protein Adsorption On And Swelling Of Polyelectrolyte Brushes: A Simultaneous Ellipsometry-Quartz Crystal Microbalance Study, Eva Bittrich, Keith B. Rodenhausen Jr., Klaus-Jochen Eichhorn, Tino Hofmann, Mathias Schubert, Manfred Stamm, Petra Uhlmann

Department of Electrical and Computer Engineering: Faculty Publications

With a coupled spectroscopic ellipsometry-quartz crystal microbalance with dissipation (QCM-D) experimental setup, quantitative information can be obtained about the amount of buffer components (water molecules and ions) coupled to a poly(acrylic acid) (PAA) brush surface in swelling and protein adsorption processes. PAA Guiselin brushes with more than one anchoring point per single polymer chain were prepared. For the swollen brushes a high amount of buffer was found to be coupled to the brush-solution interface in addition to the content of buffer inside the brush layer. Upon adsorption of bovine serum albumin the further incorporation of buffer molecules into the protein-brush …

Data Compression Concepts And Algorithms And Their Applications To Bioinformatics, Ozkan U. Nalbantoglu, David J. Russell, Khalid Sayood

Department of Electrical and Computer Engineering: Faculty Publications

Data compression at its base is concerned with how information is organized in data. Understanding this organization can lead to efficient ways of representing the information and hence data compression. In this paper we review the ways in which ideas and approaches fundamental to the theory and practice of data compression have been used in the area of bioinformatics. We look at how basic theoretical ideas from data compression, such as the notions of entropy, mutual information, and complexity have been used for analyzing biological sequences in order to discover hidden patterns, infer phylogenetic relationships between organisms and study viral …

Discrete Coordinate Transformation For Designing All-Dielectric Flat Antennas, Wenxuan Tang, Christos Argyropoulos, Efthymios Kallos, Wei Song, Yang Hao

Department of Electrical and Computer Engineering: Faculty Publications

Transformation electromagnetics provides a practical approach to control electromagnetic fields at will. Based on this principle, novel devices such as the invisible cloak have been proposed. Here we examine the extension of this technique as applied to the design of flat devices in antenna systems. A method using discrete coordinate transformation is proposed, which allows the conversion of conventional devices with curved shapes into flat systems, while preserving their non-dispersive, isotropic, broadband, and lossless properties. Two specific design examples, a flat reflector and a flat lens embedded in free space, are presented. To avoid the loss and narrow bandwidth issues …

Clustering Of Protein Families Into Functional Subtypes Using Relative Complexity Measure With Reduced Amino Acid Alphabets, Aydin Albayrak, Hasan H. Otu, Ugur O. Sezerman

Department of Electrical and Computer Engineering: Faculty Publications

Background: Phylogenetic analysis can be used to divide a protein family into subfamilies in the absence of experimental information. Most phylogenetic analysis methods utilize multiple alignment of sequences and are based on an evolutionary model. However, multiple alignment is not an automated procedure and requires human intervention to maintain alignment integrity and to produce phylogenies consistent with the functional splits in underlying sequences. To address this problem, we propose to use the alignment-free Relative Complexity Measure (RCM) combined with reduced amino acid alphabets to cluster protein families into functional subtypes purely on sequence criteria. Comparison with an alignment-based approach was …

Bioinformatic Identification And Characterization Of Human Endothelial Cell-Restricted Genes, Manoj Bhasin, Lei Yuan, Derin B. Keskin, Hasan H. Otu, Towia A. Libermann, Peter Oettgen

Department of Electrical and Computer Engineering: Faculty Publications

Background: In this study, we used a systematic bioinformatics analysis approach to elucidate genes that exhibit an endothelial cell (EC) restricted expression pattern, and began to define their regulation, tissue distribution, and potential biological role.

Results:Using a high throughput microarray platform, a primary set of 1,191 transcripts that are enriched in different primary ECs compared to non-ECs was identified (LCB >3, FDR

Conclusion: The study provides an initial catalogue of EC-restricted genes most of which are ubiquitously expressed in different endothelial cells.

Tob1 Is A Constitutively Expressed Repressor Of Liver Regeneration, Karen J. Ho, Nhue L. Do, Hasan H. Otu, Martin J. Dib, Xianghui Ren, Keiichi Enjyoji, Simon C. Robson, Ernest F. Terwilliger, Seth J. Karp

Department of Electrical and Computer Engineering: Faculty Publications

How proliferative and inhibitory signals integrate to control liver regeneration remains poorly understood. A screen for antiproliferative factors repressed after liver injury identified transducer of ErbB2.1 (Tob1), a member of the PC3/BTG1 family of mito-inhibitory molecules as a target for further evaluation. Tob1 protein decreases after 2/3 hepatectomy in mice secondary to posttranscriptional mechanisms. Deletion of Tob1 increases hepatocyte proliferation and accelerates restoration of liver mass after hepatectomy. Down-regulation of Tob1 is required for normal liver regeneration, and Tob1 controls hepatocyte proliferation in a dose-dependent fashion. Tob1 associates directly with both Caf1 and cyclindependent kinase (Cdk) 1 and …

Iterative Signal Processing In Communications, Christian Schlegel, Peter Hoeher, Owe Axelsson, Lance C. Pérez

Department of Electrical and Computer Engineering: Faculty Publications

Iterative signal processing in communications has experienced an explosive rise in popularity in recent years. The catalytic origins of this paradigm-shifting new philosophy among communications experts can be traced to the invention of turbo coding, and the subsequent rediscovery of low-density parity check (LDPC) coding, both in the field of error control coding. Both systems rely on iterative decoding algorithms to achieve their astounding performance. However, iterative signal processing is not confined to the decoding of error control codes and rather quickly spread to many other possible applications. The purpose of this special issue is to examine the concept of …

The Manifestation Of Stopping Sets And Absorbing Sets As Deviations On The Computation Trees Of Ldpc Codes, Eric T. Psota, Lance C. Perez

Department of Electrical and Computer Engineering: Faculty Publications

The error mechanisms of iterative message-passing decoders for low-density parity-check codes are studied. A tutorial review is given of the various graphical structures, including trapping sets, stopping sets, and absorbing sets that are frequently used to characterize the errors observed in simulations of iterative decoding of low-density parity-check codes. The connections between trapping sets and deviations on computation trees are explored in depth using the notion of problematic trapping sets in order to bridge the experimental and analytic approaches to these error mechanisms. A new iterative algorithm for finding low-weight problematic trapping sets is presented and shown to be capable …

Mimo Self-Encoded Spread Spectrum With Iterative Detection Over Rayleigh Fading Channels, Shichuan Ma, Lim Nguyen, Won Mee Jang, Yaoqing (Lamar) Yang

Department of Electrical and Computer Engineering: Faculty Publications

Self-encoded spread spectrum (SESS) is a novel communication technique that derives its spreading code from the randomness of the source stream rather than using conventional pseudorandom noise (PN) code. In this paper, we propose to incorporate SESS in multiple-input multiple-output (MIMO) systems as a means to combat against fading effects in wireless channels. Orthogonal space-time block-coded MIMO technique is employed to achieve spatial diversity, and the inherent temporal diversity in SESS modulation is exploited with iterative detection. Simulation results demonstrate that MIMO-SESS can effectively mitigate the channel fading effect such that the system can achieve a bit error rate of …

Non-Destructiveapproachto Ellipsometric Monitoring Of A Film Coating On The Inner Surface Of A Tube Shaped Sample, Gregory K. Prilbil, John A. Woollam, Martin M. Liphardt, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is the use of a focused electromagnetic beam which is caused to impinge on the top surface of a tube shaped sample, to investigate a film coating on inner surface during fabrication thereof and/or thereafter.

A Non-Vacuum Process For Preparing Nanocrystalline Cuin1−XGaXSe2 Materials Involving An Open-Air Solvothermal Reaction, J. Olejníček, Chad A. Kamler, A. Mirasano, A. L. Martinez-Skinner, M. A. Ingersoll, C. L. Exstrom, S. A. Darveau, J. L. Huguenin-Love, M. Diaz, Natale J. Ianno, Rodney J. Soukup

Department of Electrical and Computer Engineering: Faculty Publications

A non-vacuum, two-step process has been used to prepare a series of nanocrystalline CuIn_1−xGa_xSe₂ (x = 0, 0.25, 0.5, 0.75, 1) materials. An open-air solvothermal preparation in triethylenetetramine solvent was followed by annealing at 500 °C in a nitrogen atmosphere for 20 min. All materials have mixed clustered plate, spherical particle, and nanorod morphologies with the smallest particle diameters ranging between 20 and 40 nm. Raman spectroscopy and X-ray diffraction (XRD) confirm that indium/gallium ratio control is possible over a wide range. The solvothermal reaction step yields a mixture of chalcopyrite and Cu …

Magneto-Optical Properties Of Cobalt Slanted Columnar Thin Films, Daniel Schmidt, Tino Hofmann, Craig M. Herzinger, Eva Schubert, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

Magneto-optical properties of ferromagnetic slanted columnar thin films from cobalt made by electron-beam glancing angle deposition are reported. Magneto-optic ellipsometry in the polar Kerr effect configuration was employed to determine the field- and wavelength-dependent complex magneto-optic polarizability parameter within the spectral range from 0.74 to 3.0 eV. Kerr effect measurements and calculations reveal a strong azimuthal dependence for the incident linear polarization with peak Kerr rotation one order of magnitude larger than what has been reported for solid Co thin films.

Hydrogen In Inn: A Ubiquitous Phenomenon In Molecular Beam Epitaxy Grown Material, V. Darakchieva, K. Lorenz, N. P. Barradas, E. Alves, B. Monemar, Mathias Schubert, N. Franco, C. L. Hsiao, L. C. Chen, W. J. Schaff, L. W. Tu, T. Yamaguchi, Y. Nanishi

Department of Electrical and Computer Engineering: Faculty Publications

We study the unintentional H impurities in relation to the free electron properties of state-of-the-art InN films grown by molecular beam epitaxy (MBE). Enhanced concentrations of H are revealed in the near surface regions of the films, indicating postgrowth surface contamination by H. The near surface hydrogen could not be removed upon thermal annealing and may have significant implications for the surface and bulk free electron properties of InN. The bulk free electron concentrations were found to scale with the bulk H concentrations while no distinct correlation with dislocation density could be inferred, indicating a major role of hydrogen for …

Secure Communication Over Fading Channels With Statistical Qos Constraints, Deli Qiao, M. Cenk Gursoy, Senem Velipasalar

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, secure transmission of information over an ergodic fading channel is studied in the presence of statistical quality of service (QoS) constraints.We employ effective capacity to measure the secure throughput of the system, i.e., effective secure throughput. We assume that the channel side information (CSI) of the main and the eavesdropper channels is available at the transmitter side. Under this assumption, we investigate the optimal power control policies that maximize the effective secure throughput. In particular, it is noted that opportunistic transmission is no longer optimal and the transmitter should not wait to send the data at …

A Noncooperative Power Control Game In Multiple-Access Fading Channels With Qos Constraints, Deli Qiao, M. Cenk Gursoy, Senem Velipasalar

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, a game-theoretic analysis for the resource allocation policies in fading multiple-access channels (MAC) in the presence of quality of service (QoS) constraints is performed. Effective capacity, which provides the maximum constant arrival rate, or throughput, that a given service process can support while satisfying statistical delay constraints, is considered in a multiuser scenario. We assume that the channel side information (CSI) is available at both the receiver and transmitters, and the transmitters are selfish, rational with certain QoS constraints and average power limitations. Without the aid of the receiver, we prove that there is always a unique …

A Grammar-Based Distance Metric Enables Fast And Accurate Clustering Of Large Sets Of 16s Sequences, David J. Russell, Samuel F. Way, Andrew K. Benson, Khalid Sayood

Department of Electrical and Computer Engineering: Faculty Publications

Background: We propose a sequence clustering algorithm and compare the partition quality and execution time of the proposed algorithm with those of a popular existing algorithm. The proposed clustering algorithm uses a grammar-based distance metric to determine partitioning for a set of biological sequences. The algorithm performs clustering in which new sequences are compared with cluster-representative sequences to determine membership. If comparison fails to identify a suitable cluster, a new cluster is created.

Results: The performance of the proposed algorithm is validated via comparison to the popular DNA/RNA sequence clustering approach, CD-HIT-EST, and to the recently developed algorithm, …

Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha Ph.D., Florin Bobaru Ph.D.

Department of Engineering Mechanics: Faculty Publications

In this paper we discuss the peridynamic analysis of dynamic crack branching in brittle materials and show results of convergence studies under uniform grid refinement (m-convergence) and under decreasing the peridynamic horizon (δ-convergence). Comparisons with experimentally obtained values are made for the crack-tip propagation speed with three different peridynamic horizons.We also analyze the influence of the particular shape of themicro-modulus function and of different materials (Duran 50 glass and soda-lime glass) on the crack propagation behavior. We show that the peridynamic solution for this problem captures all the main features, observed experimentally, of dynamic crack propagation and branching, as well …