Engineering Commons^™

Data Transport System, Rahav Dor

All Computer Science and Engineering Research

To facilitate the WU Smart Home research [21] we built a system that collects data from sensors and uploads the data to the cloud. The system supports data collection from multiple locations (typically apartments) that are independent from each other, endowing the system with two benefit: distributed data collection and alleviating privacy concerns. Each location is managed by a local micro-server (μServer) that is responsible for receiving data packets from sensors and managing their transient storage. Periodically the μServer triggers a data transport process that moves the data to a cloud server where it is stored in a centralized database. …

Exploring User-Provided Connectivity, Mohammad H. Afrasiabi, Roch Guerin

All Computer Science and Engineering Research

Network services often exhibit positive and negative externalities that affect users' adoption decisions. One such service is "user-provided connectivity" or UPC. The service offers an alternative to traditional infrastructure-based communication services by allowing users to share their "home base" connectivity with other users, thereby increasing their access to connectivity. More users mean more connectivity alternatives, i.e., a positive externality, but also greater odds of having to share one's own connectivity, i.e., a negative externality. The tug of war between positive and negative externalities together with the fact that they often depend not just on how many but also which users …

Treadle Driven Lathe, Eleanor B. Mullard, Daniel Kronthal, Aaron Cohn, Robert Borovsky

Mechanical Engineering Design Project Class

The main objective of this senior design project was to design and build a treadle-driven, metal-cutting lathe that has the ability to cut 3/4" diameter material and produce small parts up to 3" long. The main challenge in this project was to successfully generate enough power through the treadle driven system to successfully cut metal at the proper specifications, while simultaneously meeting all of the user-needs. The entire system needed to be operated and pedaled by a single person, which put constraints on the location of the treadle relative to the lathe itself so the user could comfortably operate both …

Wind Walking Machine, Sam N. Lazechko, Taylor A. Justman, Will Nocka, Isaac Goldenthal

Mechanical Engineering Design Project Class

Design a machine that walks using wind power.

Treadle Driven Can Opener, Chris Lowery, Stewart Martens, Dom Quaranta

Mechanical Engineering Design Project Class

Given the task to build a treadle driven can opener that opened a can in under 5 seconds, met cost requirements, and was robust.

Orthopedic Screwdriver Design, Tiffany M. Ewing, Ryan F. Blumenstein, Beenish Qayum

Mechanical Engineering Design Project Class

Design an adjustable mechanical clutch screwdriver suitable for driving Orthopedic Screws into bones. The clutch would prevent over tightening and damaging bone material. The prototype design must demonstrate the function and ergonomics of the device and it must be suitable for modification into a medical device. Specify material changes and design details that would be needed for the ultimate production model.

Integrating Cognitive Science With Innovative Teaching In Stem Disciplines, Mark A. Mcdaniel, Regina F. Frey, Susan M. Fitzpatrick, Henry L. Roediger Iii

Books and Monographs

This volume collects the ideas and insights discussed at a novel conference, the Integrating Cognitive Science with Innovative Teaching in STEM Disciplines Conference, which was held September 27-28, 2012 at Washington University in St. Louis. With funding from the James S. McDonnell Foundation, the conference was hosted by Washington University’s Center for Integrative Research on Cognition, Learning, and Education (CIRCLE), a center established in 2011. Available for download as a PDF. Titles of individual chapters can be found at http://openscholarship.wustl.edu/circle_book/.

Image Reconstruction In Photoacoustic Computed Tomography With Acoustically Heterogeneous Media, Chao Huang

All Theses and Dissertations (ETDs)

Photoacoustic computed tomography (PACT), also known as optoacoustic or thermoacoustic tomography, is a rapidly emerging hybrid imaging modality that combines optical image contrast with ultrasound detection. The majority of currently available PACT image reconstruction algorithms are based on idealized imaging models that assume a lossless and acoustically homogeneous medium. However, in many applications of PACT these assumptions are violated and the induced photoacoustic (PA) wavefields are scattered and absorbed as they propagate to the receiving transducers. In those applications of PACT, the reconstructed images can contain significant distortions and artifacts if the inhomogeneous acoustic properties of the object are not …

Restoring Upper Extremity Mobility Through Functional Neuromuscular Stimulation Using Macro Sieve Electrodes, Erik R. Zellmer

All Theses and Dissertations (ETDs)

The last decade has seen the advent of brain computer interfaces able to extract precise motor intentions from cortical activity of human subjects. It is possible to convert captured motor intentions into movement through coordinated, artificially induced, neuromuscular stimulation using peripheral nerve interfaces. Our lab has developed and tested a new type of peripheral nerve electrode called the Macro-Sieve electrode which exhibits excellent chronic stability and recruitment selectivity. Work presented in this thesis uses computational modeling to study the interaction between Macro-Sieve electrodes and regenerated peripheral nerves. It provides a detailed understanding of how regenerated fibers, both on an individual …

Shape Optimization Of Airfoils Without And With Ground Effect Using A Multi-Objective Genetic Algorithm, Yilei He

McKelvey School of Engineering Graduate Student Theses & Dissertations

The focus of this thesis is on shape optimization using a genetic algorithm. A multi-objective genetic algorithm (MOGA) is employed to optimize the shape of an airfoil to improve its lift and drag characteristics, in particular to achieve two objectives simultaneously that is to increase its lift as well as its lift to drag ratio. The commercially available software FLUENT is employed to calculate the flow field on an adaptive structured mesh, which is generated by the commercial mesh generating software ICEM. The flow field is calculated using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a two equation k-ω …

Engineering Biosensors For Short-Chain Alcohols, Yu Xia

McKelvey School of Engineering Graduate Student Theses & Dissertations

Biofuel is a promising substitute for fossil fuel and the research of biofuel production has been extensively conducted during the recent years. Great efforts have been made to create many types of the fuel production hosts. However, effective approaches for high specificity and high throughput screening of the fuel production strains are still lacking. The cellular stress response is one universal defense mechanism when a microbial cell is exposed to an unfavorable substance or environment. It triggers a series of downstream responses when a cell senses certain chemicals. Transcriptional factors are widely used in living organisms to regulate gene expression. …

Evaluation Of The Performance Of Various Turbulence Models For Accurate Numerical Simulation Of A 2d Slot Nozzle Ejector, Colin Graham

McKelvey School of Engineering Graduate Student Theses & Dissertations

With the development over the last several decades, accurate Computational Fluid Dynamics (CFD) modeling has now become an essential part in the analysis and design of various industrial products where the fluid flow plays an important role. The goal of this thesis is to apply the CFD technology to the analysis of a 2D slot nozzle ejector which has application in Short Take-off and Landing (STOL) aircraft and other future aerospace vehicles. In the nozzle-ejector configuration, the high speed air flow from the nozzle entrains the ambient air into a mixing chamber (ejector) as a means to create additional thrust …

Optical Resonators And Fiber Tapers As Transducers For Detection Of Nanoparticles And Bio-Molecules, Huzeyfe Yilmaz

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent years, detection of biological interactions on single molecule level has aspired many researchers to investigate several optical, chemical, electrical and mechanical sensing tools. Among these tools, toroidal optical resonators lead the way in detection of the smallest particle/molecule with the real time measurements. In this work, bio-sensing capabilities of toroidal optical resonators are investigated. Bio-sensing is realized via measuring the analyte-antigen interaction while the antigen is immobilized through a novel functionalization method.

Not long ago, detection of single nanoparticles using optical resonators has been accomplished however the need for cost-effective and practical transducers demands simpler tools. A tapered …

Single Cuo Nanowires Electrical Properties And Application On Photoelectrochemical Water Splitting, Junnan Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Charge transport in single crystal, p type copper oxide (CuO) nanowires (NWs) was studied through temperature based (120 K – 400 K) current-voltage (I-V) measurements of 2-terminal single NW devices. Individual CuO NWs with an average diameter of 220 nm were attached to Au electrodes 2.5 µm apart, using a dielectrophoresis method. I-V curves showed a transition from linear behavior at low bias to strong power law dependence (I ~ V^a) at high bias, which can be attributed to space charge limited current (SCLC) mechanism. At low electrical fields (< 0.89 × 10³ V·cm^-1), the number of …

Detection Of Parkinson Disease Rest Tremor, Matthew J. Johnson

McKelvey School of Engineering Graduate Student Theses & Dissertations

Parkinson Disease (PD) is a debilitating and progressive movement disorder that is estimated to affect over six million worldwide. One of the most characteristic symptoms of PD is resting tremor, which involves unintentional and rhythmic muscle oscillations of an afflicted extremity while the muscles of said extremity are relaxed. This study involved measuring the rest tremor of 10 PD subjects, 10 Essential Tremor subjects, and 10 healthy control subjects using two devices. One device was an FDA approved accelerometry system to measure human tremor known as the Tremorometer^TM and the other was a consumer three-dimensional camera known as the …

Migrating To Ipv6 - The Role Of Basic Coordination, Mehdi Nikkhah, Roch Guerin

All Computer Science and Engineering Research

The need for a larger Internet address space was acknowledged early on, and a solution (IPv6) standardized years ago. Its adoption has, however, been anything but easy and still faces significant challenges. The situation begs the questions of "why has it been so difficult?" and "what could have been (or still be) done to facilitate this migration?" There has been significant recent interest in those questions, and the paper builds on a line of work based on technology adoption models to explore them. The results confirm the impact of several known factors, but also provide new insight. In particular, they …

Numerical Simulation And Optimization Of Carbon Dioxide Utilization And Storage In Enhanced Gas Recovery And Enhanced Geothermal Systems, James H. Biagi

McKelvey School of Engineering Graduate Student Theses & Dissertations

With rising concerns surrounding CO₂ emissions from fossil fuel power plants, there has been a strong emphasis on the development of safe and economical Carbon Capture Utilization and Storage (CCUS) technology. Two methods that show the most promise are Enhanced Gas Recovery (EGR) and Enhanced Geothermal Systems (EGS). In Enhanced Gas Recovery a depleted or depleting natural gas reservoir is re-energized with high pressure CO₂ to increase the recovery factor of the gas. As an additional benefit following the extraction of natural gas, the reservoir would serve as a long-term storage vessel for the captured carbon. CO_{2 …}

Identifying Humans By The Shape Of Their Heartbeats And Materials By Their X-Ray Scattering Profiles, Ikenna C. Odinaka

McKelvey School of Engineering Graduate Student Theses & Dissertations

Security needs at access control points presents itself in the form of human identification and/or material identification. The field of Biometrics deals with the problem of identifying individuals based on the signal measured from them. One approach to material identification involves matching their x-ray scattering profiles with a database of known materials.

Classical biometric traits such as fingerprints, facial images, speech, iris and retinal scans are plagued by potential circumvention they could be copied and later used by an impostor. To address this problem, other bodily traits such as the electrical signal acquired from the brain (electroencephalogram) or the heart …

Miniaturization Of Electrical Ultrafine Particle Sizers, Siqin He

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nanoparticles, or ultrafine particles, have potential risks for human health, and the adverse health effects caused by ultrafine particles have been proven to be size related. To meet the increasing demanding for personal exposure monitoring and spatial distribution measurements of ultrafine particles, this dissertation studied the development and miniaturization of electrical ultrafine particle sizers (EUPS). There are three essential components for developing a EUPS unit: a charger to electrically charge the sample particles, an electrical mobility classifier to classify the charged particles, and a downstream particle count detector to measure the number concentrations. Two generations of EUPS were developed in …

Modeling And Development Of Iterative Reconstruction Algorithms In Emerging X-Ray Imaging Technologies, Jiaofeng Xu

All Theses and Dissertations (ETDs)

Many new promising X-ray-based biomedical imaging technologies have emerged over the last two decades. Five different novel X-ray based imaging technologies are discussed in this dissertation: differential phase-contrast tomography (DPCT), grating-based phase-contrast tomography (GB-PCT), spectral-CT (K-edge imaging), cone-beam computed tomography (CBCT), and in-line X-ray phase contrast (XPC) tomosynthesis. For each imaging modality, one or more specific problems prevent them being effectively or efficiently employed in clinical applications have been discussed. Firstly, to mitigate the long data-acquisition times and large radiation doses associated with use of analytic reconstruction methods in DPCT, we analyze the numerical and statistical properties of two classes …

A Study Of Sampling Strategies For Helical Ct, Daheng Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Two classes of subsampling strategies, partially inspired by ideas from compressed sensing (CS), are developed and tested using real medical x-ray CT data acquired with a helical geometry. A version of the Feldkamp algorithm for helical x-ray CT is described. An alternating minimization (AM) algorithm for finding the maximum-likelihood estimates of attenuation functions in transmission X-ray tomography, developed by O’Sullivan and Benac, is then introduced. The derivation of this AM algorithm is extended to include an optional regularization term, which makes it a MAP estimate. A Newton’s method with trust region modification is implemented for the regularization. In addition, the …

Engineered Plasmonic Nanostructures For Nanomedicine, Christopher Matthew Portz

McKelvey School of Engineering Graduate Student Theses & Dissertations

No abstract provided.

Real-Time Image Processing On An Fpga For An Intraoperative Goggle Device, Yiyi Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

The emergence of near-infrared dyes for fluorescence imaging has had a tremendous impact in the medical field. In particular, indocyanin green (ICG) has been widely used for assessing tumor margins during intraoperative procedures. Typically, the dye is intravenously injected into the patient, and after 24 hours the dye is removed from the patient’s body, except where binding between the dye and tumor cells has occurred. This selective binding between ICG and cancerous tissue allows for easy and accurate detection of cancer margins as well as detection of metastasis throughout the patient’s body. In order to detect the binding sites, a …

Global Edf Scheduling For Parallel Real-Time Tasks, Jing Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

As multicore processors become ever more prevalent, it is important for real-time programs to take advantage of intra-task parallelism in order to support computation-intensive applications with tight deadlines. In this thesis, we consider the Global Earliest Deadline First (GEDF) scheduling policy for task sets consisting of parallel tasks. Each task can be represented by a directed acyclic graph (DAG) where nodes represent computational work and edges represent dependences between nodes. In this model, we prove that GEDF provides a capacity augmentation bound of 4-2/m and a resource augmentation bound of 2-1/m. The capacity augmentation bound acts as a linear-time schedulability …

An Approach To Thermocouple Temperature Measurements That Reduces Uncertainties Associated With Radiative Corrections, Siddharth Krishnan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Obtaining accurate temperature measurements in flame environments with thermocouples is extremely challenging due to the effects of radiative heat loss. These losses are difficult to quantify and often cannot be corrected for or minimized without sacrificing spatial resolution. In this work, a new experimental methodology is presented that has shown potential to minimize the temperature correction by both increasing and controlling the effects of convection. This is accomplished through high speed rotation of the thermocouple. The rotation yields a high and known convective velocity over the thermocouple. Heat transfer can then be modeled for the thermocouple, and a functional relationship …

Multiscale Modeling, Reformulation, And Efficient Simulation Of Lithium-Ion Batteries, Paul Wesley Clairday Northrop

All Theses and Dissertations (ETDs)

Lithium-ion batteries are ubiquitous in modern society, ranging from relatively low-power applications, such as cell phones, to very high demand applications such as electric vehicles and grid storage. The higher power and energy density of lithium-ion batteries compared to other forms of electrochemical energy storage makes them very popular in such a wide range of applications. In order to engineer improved battery design and develop better control schemes, it is important to understand internal and external battery behavior under a variety of possible operating conditions. This can be achieved using physical experiments, but those can be costly and time consuming, …

Design And Implementation Of Position-Encoded Microfluidic Microsphere-Trap Arrays, Xiaoxiao Xu

All Theses and Dissertations (ETDs)

Microarray devices are useful for detecting and analyzing biological targets, such as DNAs, mRNAs, proteins, etc. Applications of microarrays range from fundamental research to clinical diagnostics and drug discovery. In this dissertation, we consider a microsphere array device with predetermined positions of the microspheres. The microspheres are conjugate on their surfaces with molecular probes to capture the targets, and the targets are identified by the microspheres' positions. We implement the microsphere arrays by employing microfluidic technology and a hydrodynamic trapping mechanism. We call our device microfluidic microsphere-trap arrays. To fully realize the potential of the device in biomedical applications, we …

Power System State Estimation And Renewable Energy Optimization In Smart Grids, Peng Yang

All Theses and Dissertations (ETDs)

The future smart grid will benefit from real-time monitoring, automated outage management, increased renewable energy penetration, and enhanced consumer involvement. Among the many research areas related to smart grids, this dissertation will focus on two important topics: power system state estimation using phasor measurement units (PMUs), and optimization for renewable energy integration.

In the first topic, we consider power system state estimation using PMUs, when phase angle mismatch exists in the measurements. In particular, we build a measurement model that takes into account the measurement phase angle mismatch. We then propose algorithms to increase state estimation accuracy by taking into …

Optimization Of Layered Battery Cathode Materials Synthesized Via Spray Pyrolysis, Miklos Lengyel

All Theses and Dissertations (ETDs)

Rapid advancements of techniques for the synthesis of Li-ion battery materials are critically needed to address the requirement of a clean and efficient transportation sector. The current research serves this goal by developing an approach to producing layered cathode materials with superior electrochemical performance for electric vehicles (EVs). Current widespread application of EVs is primarily limited by their short range and their high price, which is primarily driven by the cost of the battery pack. The cost of the battery pack is driven by the cost of the cathode material that empowers it.

Novel, high throughput and inexpensive synthesis methods …

Submicron-Resolution Photoacoustic Microscopy Of Endogenous Light-Absorbing Biomolecules, Chi Zhang

All Theses and Dissertations (ETDs)

Photoacoustic imaging in biomedicine has the unique advantage of probing endogenous light absorbers at various length scales with a 100% relative sensitivity. Among the several modalities of photoacoustic imaging, optical-resolution photoacoustic microscopy (OR-PAM) can achieve high spatial resolution, on the order of optical wavelength, at <1 mm depth in biological tissue (the optical ballistic regime). OR-PAM has been applied successfully to structural and functional imaging of blood vasculature and red blood cells in vivo. Any molecules which absorb sufficient light at certain wavelengths can potentially be imaged by PAM. Compared with pure optical imaging, which typically targets fluorescent markers, label-free PAM avoids the major concerns that the fluorescent labeling probes may disturb the function of biomolecules and may have an insufficient density. This dissertation aims to advance label-free OR-PAM to the subcellular scale.

The first part of this dissertation describes the technological advancement of PAM yielding high spatial resolution in 3D. The lateral resolution was improved by using optical objectives with high numerical apertures for optical focusing. The axial resolution was improved by using broadband ultrasonic transducers for ultrasound detection. We achieved 220 nm lateral resolution in transmission …