Engineering Commons^™

Nano-Structured Optical Thin Films And Their Applications, Andrew Sarangan

Andrew Sarangan

No abstract provided.

Probing Vocal Fold Fibroblast Response To Hyaluronan In 3d Contexts, Dany Munoz Pinto, Andrea Jimenez-Vergara, L Gelves, Rebecca Mcmahon, Viviana Guiza-Arguello, Mariah Hahn

Dany J. Munoz Pinto

A number of treatments are being investigated for vocal fold (VF) scar, including designer implants. The aim of the present study was to validate a 3D model system for probing the effects of various bioactive moieties on VF fibroblast (VFF) behavior toward rational implant design. We selected poly(ethylene glycol) diacrylate (PEGDA) hydrogels as our base-scaffold due to their broadly tunable material properties. However, since cells encapsulated in PEGDA hydrogels are generally forced to take on rounded/stellate morphologies, validation of PEGDA gels as a 3D VFF model system required that the present work directly parallel previous studies involving more permissive scaffolds. …

Exploring What Engineering Doctoral Students Aspiring To Faculty Careers Learn About Research From Faculty Mentors. Frontiers In Education, (Fie) Annual Meeting, San Antonio, Tx., Tonya Saddler

Tonya N. Saddler, Ph.D.

No abstract provided.

Theory And Computation Of Photopolymerization Induced Phase Transition And Morphology Development In Blends Of Crystalline Polymer And Photoreactive Monomer, Thein Kyu

Thein Kyu

A hypothetical phase diagram of a crystalline polymer/photoreactive monomer mixture has been calculated on the basis of phase field (PF) free energy of crystal solidification in conjunction with Flory-Huggins (FH) free energy of liquid-liquid demixing to guide the morphology development during photopolymerization of poly(ethylene oxide)/triacrylate blend. The self-consistent solution of the combined PF-FH theory exhibits a crystalline-amorphous phase diagram showing the coexistence of solid+liquid gap bound by the liquidus and solidus lines, followed by an upper critical solution temperature at a lower temperature. When photopolymerization was triggered in the isotropic region, i.e., slightly above the crystal melting transition temperatures, the …

Saddler, T.N., Trautvetter, L., & Mckenna, A.F. (2009, October). Prototyping The Engineer Of 2020: A Curricular Examination Of Two Exemplary Institutions Preparing Undergraduate Engineers. Frontiers In Education, (Fie) Annual Meeting, San Antonio, Tx., Tonya Saddler

Tonya N. Saddler, Ph.D.

No abstract provided.

Mitigation Of Control Channel Jamming Under Node Capture Attacks, Patrick Tague, Mingyan Li, Radha Poovendran

Patrick Tague

Availability of service in many wireless networks depends on the ability for network users to establish and maintain communication channels using control messages from base stations and other users. An adversary with knowledge of the underlying communication protocol can mount an efficient denial of service attack by jamming the communication channels used to exchange control messages. The use of spread spectrum techniques can deter an external adversary from such control channel jamming attacks. However, malicious colluding insiders or an adversary who captures or compromises system users are not deterred by spread spectrum, as they know the required spreading sequences. For …

Simulation Of Mc-Ds-Cdma-System Based On: Multi-Wavelets Transform Over Wireless Channel, Amean Al_Safi

Amean S Al_Safi

In this paper a scheme was proposed to improve the performance form the Bit Error Rate (BER) view point for Multicarrier-Direct-Sequence-Code Division Multiple Access (MC-DS-CDMA) system in wireless channel. The conventional MC-DS-CDMA-system is based on Fast Fourier Transform (FFT). The proposed system was based on Multi-Wavelet transform (MWT). Simulation results are done in three different types of channels. Simulation shows that the proposed system outperforms the conventional system in addition to a coded version of the conventional system. Also the MC-DS-CDMA-system which is based on MWT achieves better performance with the same loss in bandwidth than the MC-DS-CDMA-system based on …

Protecting Airline Passengers In The Age Of Terrorism Chapter:Preparing For In-Flight Security Threats, Lori Brown

Lori J. Brown

When it comes to airline security, there is nothing more important than getting people to their destinations safely. Transportation security is also a key component in the overall mission of protecting the nation against terrorist attacks. But airline security is a tricky goal—how do you achieve acceptable levels of security at a reasonable cost and without unduly inconveniencing passengers or invading their privacy? That's exactly what this book is about. Experts examine the latest thinking and analyze the latest research on air passenger security, discuss current practices, and show how technology can solve myriad problems. The book will, in short, …

A Preliminary Study On The Effectiveness Of Inquiry-Based Activities For Addressing Misconceptions Of Undergraduate Engineering Students, Michael Prince, M. Vigeant, K. Nottis

Michael J. Prince

No abstract provided.

Electrospinning Route For The Fabrication Of Pn Junction Using Nanofiber Yarns, Darrell Reneker

Darrell Hyson Reneker

Electrospinning is a simple, versatile, and cost effective method for generating nanoscale fibers, wires, and tubes. Nanowires and nanotubes could be important building blocks for nanoscale electronics, optoelectronics, and sensors as they can function as miniaturized devices as well as electrical interconnects. We report on a simple method to fabricate free standing ceramic nanofiber heterostructures, which exhibit rectifying behavior of a p-n junction

Production Of Meso-And Giga-Porous Zirconia Particles—An Improved Multi-Step Particle Aggregation Process, Abhinandan Pattanayak

Abhinandan Pattanayak

No abstract provided.

Uncoupled Investigation Of Scaffold Modulus And Mesh Size On Smooth Muscle Cell Behavior, Dany Munoz Pinto, Allen Bulick, Mariah Hahn

Dany J. Munoz Pinto

Although scaffold material properties are known to critically impact cell behavior, it has proven difficult to correlate specific cell responses to isolated scaffold parameters, inhibiting rational design of scaffold material properties. The aim of this study was to validate a systematic approach for evaluating the influence of initial scaffold modulus and mesh size on cell extracellular matrix (ECM) deposition and phenotype. Poly(ethylene glycol) diacrylate (PEGDA) hydrogels were selected for this study because of their tunable material properties. Following screening of six distinct PEGDA hydrogels, three formulations were identified which permitted uncoupled investigation of scaffold mesh size and modulus within the …

Artificial Neural Network Method For Solution Of Boundary Value Problems With Exact Satisfaction Of Arbitrary Boundary Conditions, Kevin Mcfall, J. Mahan

Kevin McFall

Saw Dust And Neem Bark As Low-Cost Natural Biosorbent For Adsorptive Removal Of Zn (Ii) And Cd (Ii) Ions From Aqueous Solutions, Tarun Naiya, Pankaj Chowdhury, Ashim Bhattacharya, Sudip Das

PC

The ability of saw dust and neem bark as low-cost natural adsorbents were investigated for adsorptive removal of Zn(II) and Cd(II) ions from aqueous solutions. Various physico-chemical parameters such as pH, initial metal ion concentration, and adsorbent dosage level and equilibrium contact time were studied. The optimum pH for adsorption was found to be 5 for Zn(II) and 6 for Cd(II). Kinetics data were best described by pseudo-second-order model. Mass transfer coefficients were also determined for individual adsorbents for removal of Zn(II) and Cd(II) ions from aqueous solutions. The equilibrium adsorption data were fitted to Langmuir and Freundlich isotherm models …

A Fully Automated Non-External Marker 4d-Ct Sorting Algorithm Using A Serial Cine Scanning Protocol, Greg Carnes, Stewart Gaede, Edward Yu, Jake Van Dyk, Jerry Battista, Ting-Yim Lee

Edward Yu

Current 4D-CT methods require external marker data to retrospectively sort image data and generate CT volumes. In this work we develop an automated 4D-CT sorting algorithm that performs without the aid of data collected from an external respiratory surrogate. The sorting algorithm requires an overlapping cine scan protocol. The overlapping protocol provides a spatial link between couch positions. Beginning with a starting scan position, images from the adjacent scan position (which spatial match the starting scan position) are selected by maximizing the normalized cross correlation (NCC) of the images at the overlapping slice position. The process was continued by 'daisy …

Lamina Propria Cellularity And Collagen Composition: An Integrated Assessment Of Structure In Humans, Dany Munoz Pinto, Peter Whittaker, Mariah Hahn

Dany J. Munoz Pinto

Objectives: In this study, we quantitatively examined cell density, collagen types I and III, and regional variations in collagen fiber thickness and orientation in the human midmembranous vocal fold lamina propria (LP).

Methods: Lamina propria samples were solubilized with proteinase K or with cyanogen bromide. Cell density was assessed in proteinase K digests by measuring DNA and normalizing it to tissue total protein. Collagen types I and III were quantified by enzyme-linked immunosorbent assay–based detection of collagen type–specific peptides generated by cyanogen bromide digestion. In addition, LP total collagen was determined by measuring sample hydroxyproline levels. Variations in collagen fiber …

Impact Of Endothelial Cells And Mechanical Conditioning On Smooth Muscle Cell Extracellular Matrix Production And Differentiation, Allen Bulick, Dany Munoz Pinto, Xin Qu, Mousami Mani, Deissy Cristancho, Matthew Urban, Mariah Hahn

Dany J. Munoz Pinto

The aim of the current study was to explore the separate and coupled effects of endothelial cell (EC) presence and mechanical conditioning on smooth muscle cell (SMC) responses by combining bilayered poly(ethylene glycol) diacrylate (PEGDA) hydrogels with a pulsatile flow bioreactor. Each construct was composed of an outer PEGDA layer containing SMC and an inner PEGDA layer, either with or without EC. After an initial 3 days of static culture, EC+ and EC− constructs were each further divided into two subgroups, half of which received mechanical conditioning mimetic of late gestation (mean pressures of ∼50 mmHg and peak-to-trough pressure differentials …

Sonochemical Degradation Of Chlorinated Organic Compounds, Phenolic Compounds And Organic Dyes–A Review, Pankaj Chowdhury, T. Viraraghavan

PC

Sonochemical processes have been widely used in chemistry and chemical engineering field. Recently, these processes have found new applications in the environmental field, because of advantages in terms of operational simplicity, secondary pollutant formation and safety. Several studies have reported on sonochemical degradation of organic compounds that are toxic in nature. The objective of this review was to identify and examine some of the studies on sonochmical degradation of chlorinated organic compounds, phenolic compounds and organic dyes. This review also examines the basic theory of sonochemical reactions and the use of sonochemical reactors for environmental applications.

Evaluating The Vulnerability Of Network Traffic Using Joint Security And Routing Analysis, Patrick Tague, David Slater, Jason Rogers, Radha Poovendran

Patrick Tague

Joint analysis of security and routing protocols in wireless networks reveals vulnerabilities of secure network traffic that remain undetected when security and routing protocols are analyzed independently. We formulate a class of continuous metrics to evaluate the vulnerability of network traffic as a function of security and routing protocols used in wireless networks. We develop two complementary vulnerability definitions using set theoretic and circuit theoretic interpretations of the security of network traffic, allowing a network analyst or an adversary to determine weaknesses in the secure network. We formalize node capture attacks using the vulnerability metric as a nonlinear integer programming …

A Computationally Efficient Algorithm For Undiscounted Markov Decision Processes With Restricted Observations, Lauren Davis, Thom Hodgson, Russell King, Wenbin Wei

Dr. Lauren B Davis

We present a computationally efficient procedure to determine control policies for an infinite horizon Markov Decision process with restricted observations. The optimal policy for the system with restricted observations is a function of the observation process and not the unobservable states of the system. Thus, the policy is stationary with respect to the partitioned state space. The algorithm we propose addresses the undiscounted average cost case. The algorithm combines a local search with a modified version of Howard's (Dynamic programming and Markov processes, MIT Press, Cambridge, MA, 1960) policy iteration method. We demonstrate empirically that the algorithm finds the optimal …

The Use Of Ct Density Changes At Internal Tissue Interfaces To Correlate Internal Organ Motion With An External Surrogate, Stewart Gaede, Gregory Carnes, Edward Yu, Jake Van Dyk, Jerry Battista, Ting-Yim Lee

Edward Yu

The purpose of this paper is to describe a non-invasive method to monitor the motion of internal organs affected by respiration without using external markers or spirometry, to test the correlation with external markers, and to calculate any time shift between the datasets. Ten lung cancer patients were CT scanned with a GE LightSpeed Plus 4-Slice CT scanner operating in a ciné mode. We retrospectively reconstructed the raw CT data to obtain consecutive 0.5 s reconstructions at 0.1 s intervals to increase image sampling. We defined regions of interest containing tissue interfaces, including tumour/lung interfaces that move due to breathing …

Mac Pgp Encryption, Elizabeth Scheyder

Elizabeth C Scheyder

No abstract provided.

Balancing The R With The E In Reu Programs, Sarah Spence Adams, Rick Gillman, Darren Narayan

Sarah Spence Adams

Externally or internally funded Research Experience for Undergraduates (REU) programs offer students the opportunity to work with faculty on unsolved problems and can serve as a highlight of their undergraduate career. The overall goal of these formative programs is that students and faculty have an enjoyable experience as they investigate the horizon of knowledge. However, there is a question on how much a program should focus on research and how much emphasis should be placed on the experience. In the end, both aspects should be given considerable weight.

The Influence Of Heterogeneity In Grain Boundary Sliding Resistance On The Constitutive Behavior Of Aa5083 During High-Temperature Deformation, David Cipoletti, A.F. Bower, Y. Qi, P.E. Krajewski

David E. Cipoletti

No abstract provided.

Smart Manufacturing - Interoperability Lessons From Manufacturing's Turn, Steven Ray

Steven R Ray

No abstract provided.

Tradeoffs Between Jamming Resilience And Communication Efficiency In Key Establishment, Patrick Tague, David Slater, Radha Poovendran, Brian Matt

Patrick Tague

We address the problem of allowing authorized users, who do not preshare a common key, to effectively exchange key establishment messages over an insecure channel in the presence of jamming and message insertion attacks. In this work, we jointly consider the security and efficiency of key exchange protocols, focusing on the interplay between message fragmentation, jamming resilience, and verification complexity for protocol optimization. Finally, we present three fragment verification schemes and demonstrate through analysis and simulation that in comparison with existing approaches, they can significantly decrease the amount of time required for key establishment without degrading the guaranteed level of …