Engineering Commons^™

Relative Navigation Of Autonomous Gps-Degraded Micro Air Vehicles, David O. Wheeler, Daniel P. Koch, James S. Jackson, Gary J. Ellingson, Paul W. Nyholm, Timothy W. Mclain, Randal W. Beard

Faculty Publications

Many current approaches for navigation of micro air vehicles (MAVs) in GPS-degraded environments use a globally-referenced state for estimation and control, even though this state is not observable when GPS is unavailable. By working with respect to a local reference frame, the relative navigation (RN) framework presented in this paper ensures that the state maintains observability and that the uncertainty remains bounded, consistent, and normally-distributed. RN further insulates flight-critical estimation and control processes from the large global updates common in GPS-degraded MAV flight. This paper provides a thorough description of the details needed to successfully implement the RN framework on …

Design And Validation Of Pressure Based Flow Rate Soft Sensor For Freeze-Drying, Pasita Pibulchinda, Tong Zhu, Vaibhav Kshirsagar, Alina A. Alexeenko

The Summer Undergraduate Research Fellowship (SURF) Symposium

Lyophilization or freeze drying is a process of removing water by sublimation. It is commonly used to extend the shelf life of drugs in the pharmaceutical industry. Because the process is costly and time consuming, precise and efficient pressure, temperature control and drying time estimation are required. It is the goal of freeze-drying to run at maximum capacity while staying within the safe zone by carefully controlling the sublimation rate. Currently, real time estimation of sublimation rate is still challenging. The technique available called Tunable diode laser absorption spectroscopy (TDLAS) is invasive, and requires major modifications. The current study focuses …

Parallel Computation Using Mems Oscillator-Based Computing System, Xinrui Wang, Ilias Bilionis, Salar Safarkhani

The Summer Undergraduate Research Fellowship (SURF) Symposium

In recent years, parallel computing systems such as artificial neural networks (ANNs) have been of great interest. In these systems which emulate the behavior of human brains, the processing is carried out simultaneously. However, it is still a challenging engineering problem to design highly efficient hardware for parallel computing systems. We will study the properties of networks of Microelectromechanical System (MEMS) oscillators to explore their capabilities as parallel computing infrastructure. Furthermore, we simulate the time-variant states of MEMS oscillators network under various initial conditions and performance of certain tasks. Recent theoretical results show that networks of MEMS oscillators have some …

Interplay Of Quantum Size Effect, Anisotropy And Surface Stress Shapes The Instability Of Thin Metal Films, Mikhail Khenner

Mathematics Faculty Publications

Morphological instability of a planar surface ([111], [011], or [001]) of an ultra-thin metal film is studied in a parameter space formed by three major effects (the quantum size effect, the surface energy anisotropy and the surface stress) that influence a film dewetting. The analysis is based on the extended Mullins equation, where the effects are cast as functions of the film thickness. The formulation of the quantum size effect (Z. Zhang et al., PRL 80, 5381 (1998)) includes the oscillation of the surface energy with thickness caused by electrons confinement. By systematically comparing the effects, their contributions into the …

Process Considerations For Protein A Affinity Capture, Virus Inactivation, And Linked Polishing Steps In Multi-Column Continuous Purification Of Monoclonal Antibodies, Robert Mierendorf, Tom Van Oosbree, Anthony Grabski, William Wessel, Emily Schirmer

Integrated Continuous Biomanufacturing III

Multi-column continuous chromatography (MCC) offers significant economic advantages over traditional batch methods for purification of monoclonal antibodies (mAbs), including increased resin capacity utilization, smaller columns, reduced buffer consumption, and faster process time. The Protein A capture step is a primary target to apply MCC due to its high cost, which is driven even higher as improvements in upstream processing have produced a steady increase in mAb titers. In this study we consider the key factors in designing an MCC process that optimizes productivity. Process design begins with determination of the feed duration, which is governed by the mAb titer, column …

Performance Assessment Of Diffuse Optical Spectroscopic Imaging Instruments In A 2-Year Multicenter Breast Cancer Trial, Anais Leproux, Thomas D.O. Sullivan, Albert E. Cerussi, Amanda Durkin, Brian Hill, Nola M. Hylton, Arjun G. Yodh, Stefan A. Carp, David A. Boas, Shudong Jiang, Keith D. Paulsen, Brian W. Pogue, Darren M. Roblyr, Wei T. Yang, Bruce J. Tromberg

Dartmouth Scholarship

We present a framework for characterizing the performance of an experimental imaging technology, diffuse optical spectroscopic imaging (DOSI), in a 2-year multicenter American College of Radiology Imaging Network (ACRIN) breast cancer study (ACRIN-6691). DOSI instruments combine broadband frequency-domain photon migration with time-independent near-infrared (650 to 1000 nm) spectroscopy to measure tissue absorption and reduced scattering spectra and tissue hemoglobin, water, and lipid composition. The goal of ACRIN-6691 was to test the effectiveness of optically derived imaging endpoints in predicting the final pathologic response of neoadjuvant chemotherapy (NAC). Sixty patients were enrolled over a 2-year period at participating sites and received …

Multiphysics Simulation Of Low-Amplitude Acoustic Wave Detection By Piezoelectric Wafer Active Sensors Validated By In-Situ Ae-Fatigue Experiment, Yeasin Bhuiyan, Victor Giurgiutiu

Faculty Publications

Piezoelectric wafer active sensors (PWAS) are commonly used for detecting Lamb waves for structural health monitoring application. However, in most applications of active sensing, the signals are of high-amplitude and easy to detect. In this article, we have shown a new avenue of using the PWAS transducer for detecting the low-amplitude fatigue-crack related acoustic emission (AE) signals. Multiphysics finite element (FE) simulations were performed with two PWAS transducers bonded to the structure. Various configurations of the sensors were studied by using the simulations. One PWAS was placed near to the fatigue-crack and the other one was placed at a certain …

Learning Extreme Verification Latency Quickly With Importance Weighting: Fast Compose & Level_Iw, Muhammad Umer

Theses and Dissertations

One of the more challenging real-world problems in computational intelligence is to learn from non-stationary streaming data, also known as concept drift. Perhaps even a more challenging version of this scenario is when -- following a small set of initial labeled data -- the data stream consists of unlabeled data only. Such a scenario is typically referred to as learning in initially labeled nonstationary environment, or simply as extreme verification latency (EVL). This thesis introduces two different algorithms to operate in this domain. One of these algorithms is a simple modification of our prior work, COMPOSE (COMPacted Object Sample Extraction), …

A Novel Device For Mr Foot Perfusion Stress Testing, David John Muccigrosso

McKelvey School of Engineering Graduate Student Theses & Dissertations

No abstract provided.

Single-Step, Atmospheric Pressure Chemical Vapor Deposition Of Methylammonium Bismuth Iodide Thin Films, Xiao Chen

McKelvey School of Engineering Graduate Student Theses & Dissertations

Lead halide perovskites (CH₃NH₃PbI₃ and its variants) are promising solar cell absorber materials. Though the reported power conversion efficiencies of lead halide perovskite solar cells (up to 21%) are competitive with commercial silicon solar cells, lead toxicity in these perovskites present a challenge to further scale-up and eventual commercialization. Recently, bismuth (Bi³⁺) based organic halide perovskite has drawn attention as a substitution for lead-free perovskites, since it is a non-toxic 6p-block element, isoelectronic with Pb²⁺. Methylammonium bismuth iodide ((CH₃NH₃)₃Bi₂I₉) is reported …

Jme 4110 Phenode Camera Arm Design Project, Kelsey M. Wortmann, Paul Masnica, Matthias Sommer

Washington University / UMSL Mechanical Engineering Design Project JME 4110

The goal of this design project was to create an extendable camera arm capable of attaching to the shell of the PheNode in-field apparatus created by researchers at the Donald Danforth Plant Science Center. The camera arm extends 36 inches in length, can rotate 180 degrees, and successfully holds a camera for plant imaging with minimal vibrations. We have designed an affordable camera arm that is stable and meets the design parameters given. Our design process is documented in the following report.

Jme 4110 Final Design Report - Plant Growth Chamber, Deontez Myers, Chad Szwargulski

Washington University / UMSL Mechanical Engineering Design Project JME 4110

To facilitate study of resource use efficiency in crop plants, it is necessary to pulse-saturate them with certain stable isotopes. This is done by exposing the shoots to gases and the roots to liquid. We were tasked with designing a system to deliver and control this process.

Jme 4110 Seed Aerodynamics, Kristin Gonzalez, Vladimir Sidorov

Washington University / UMSL Mechanical Engineering Design Project JME 4110

This is a report discussing the analysis and results of a wind tunnel that was created to find the terminal velocity of a variety of seeds.

Jme 4110 Seed Cross-Breeze Distance Tester, Ty Krewson, John Jensen, Emily Dahlberg

Washington University / UMSL Mechanical Engineering Design Project JME 4110

Because seeds vary in shape, size, and weight, their behaviors in cross-breezes vary as well. The customer’s laboratory is researching seeds for prairie grasses. Their laboratory currently has data for seed structures; however, data for seed dispersion is needed to provide a better correlation to known environmental and genetic factors such as precipitation and DNA changes. The Seed Cross-Breeze Distance Tester is a controlled chamber designed to test the distance a seed will travel in a user-specified windspeed.

Effects Of Flexible Substrates On The Performance Of Wearable Antennas, Ahmed Salam Kashkool

Theses and Dissertations

Due to market trends and rapid development in the wireless technology, wearable devices are expected to become part of our daily life like Google Glass, health monitors, smart watches and so on. The electronics market has oriented toward portable and fancy flexible devices due to their invisibility, outstanding view and disposability. The past decade witnessed an extensive research focused on the development and optimisation of flexible displays. Flexible displays are considered as an appealing and promising technology due to their low profile, low cost, light weight, and portability. Wearable displays deemed as a promising technology applicable to a wide spectrum …

Cfd Performance Of Turbulence Models For Flow From Supersonic Nozzle Exhausts, Han Ju Lee

McKelvey School of Engineering Graduate Student Theses & Dissertations

The goal of this thesis is to compare the performance of several eddy-viscosity turbulence models for computing supersonic nozzle exhaust flows. These flows are of relevance in the development of future supersonic transport airplane. Flow simulations of exhaust flows from three supersonic nozzles are computed using ANSYS Fluent. Simulation results are compared to experimental data to assess the performance of various one- and two-equation turbulence models for accurately predicting the supersonic plume flow. One particular turbulence model of interest is the Wray-Agarwal (WA) turbulence model. This is a neat model which has demonstrated promising results mimicking the strength of two …

Past, Present And Future Of Surgical Meshes: A Review, Karen Baylón, Perla Rodríguez-Camarillo, Alex Elías-Zúñiga, Jose Antonio Díaz-Elizondo, Robert Gilkerson, Karen Lozano

Mechanical Engineering Faculty Publications

Surgical meshes, in particular those used to repair hernias, have been in use since 1891. Since then, research in the area has expanded, given the vast number of post-surgery complications such as infection, fibrosis, adhesions, mesh rejection, and hernia recurrence. Researchers have focused on the analysis and implementation of a wide range of materials: meshes with different fiber size and porosity, a variety of manufacturing methods, and certainly a variety of surgical and implantation procedures. Currently, surface modification methods and development of nanofiber based systems are actively being explored as areas of opportunity to retain material strength and increase biocompatibility …

Development And Validation For A Mobile Speech-In-Noise Audiometric Task, Tommy Peng

McKelvey School of Engineering Graduate Student Theses & Dissertations

Traditional speech-in-noise hearing tests are performed by clinicians with specialized equipment. Furthermore, these tasks often present contextually weak sentences in background babble, which are poor representations of real-world situations. This study proposes a mobile audiometric task, Semantic Auditory Search, which uses the Android platform to bypass the need for specialized equipment and presents multiple tasks of two competing real-world conversations to estimate the user’s speech-in-noise hearing ability. Through linear regression models built from data of seventy-nine subjects, three Semantic Auditory Search metrics have been shown to have statistically significant (p < 0.05) with medium effects sizes for predicting QuickSIN SNR50. The internal consistency of the task was also high, with a Cronbach’s alpha of 0.88 or more across multiple metrics. In conclusion, this preliminary study suggests that Semantic Auditory Search can accurately and reliably perform as an automated speech-in-noise hearing test. It also has tremendous potential for extension into automated tests of cognitive function, as well.

Effects Of Graphical Weather Information Versus Textual Weather Information On Situation Awareness In Meteorology, Stefan Melendez M.S.A., Andrew Dattel Ph.D., Christopher Herbster Ph.D., Debbie Schaum M.A., Andrey Babin

National Training Aircraft Symposium (NTAS)

Prior to a flight, pilots gather meteorological information in order to assess the weather conditions pertaining to their flight and to make decisions based on it. This information can come in various formats, such as text and graphical weather information. Research has shown that people have varying learning preferences and that most people prefer visual learning to verbal learning (i.e., graphical over text). It is hypothesized that this difference in learning preference can affect the way pilots interpret and apply the information they obtain prior to their flight. The researcher hypothesizes that graphical weather information has a greater, more positive …

Improving Instructor Quality Using The Conversation Analytic Role-Play Method (Carm), William A. Tuccio Ph.D.

National Training Aircraft Symposium (NTAS)

The audience will learn about Stokoe’s Conversation Analytic Role-play Method (CARM) (http://www.carmtraining.org) and how it has been used to study and improve talk-in-interaction in professional settings. CARM is a proven, research-based methodology which collects large volumes of recorded audio and/or video particular to a professional setting and then uses detailed transcription and conversation analysis to identify systematic patterns of interaction and problems thereof. Actual excerpts from the dataset are appropriately anonymized and used by facilitators in a workshop setting to create authentic role-play.

The presentation will explain how CARM has been applied to help improve flight instructor teaching …

An Alternative Method Of Identification Of A Failed Engine In Twin-Engine Turboprop Aircraft, Andrey Babin, Andrew R. Dattel Ph.D.

National Training Aircraft Symposium (NTAS)

Previous incidents and accidents involving twin-engine aircraft, including the recent TransAsia Flight 235 crash, have revealed that pilots are prone to mistakes in identifying the engine that fails, and subsequently, shutting down the wrong engine, i.e. perfectly working engine. Most accidents of this type happen on takeoff when pilot workload is at its highest level. It may be that the current training procedure for engine failures on takeoff, called identify-verify-feather (IVF), is counterintuitive and may lead to greater confusion. IVF is based on haptic sensory channel, which is known to be less effective than visual channel. This study proposes a …

Ozone Interaction With Indoor Building Materials And Hvac Filters, Omed Akber Abbass

Dissertations and Theses

As modern life develops, humans spend most of their time inside buildings. Understanding the effects of different building materials that exist indoors on indoor air quality is crucial to ensure comfort, health, and productivity of building occupants. Indoor air quality (IAQ) is an important field of building science that focuses on studying the existence of different compounds indoors. These compounds include: airborne particles such as dust, volatile organic compounds (VOCs) such as carbonyls, reactive gases such as radon, ozone and others. Ozone is a strong oxidant gas that has adverse effects on human health, and is highly reactive with building …

Jme 4110- Solar Panel Tracker, Bob Stretch, James Eimer, Patrick Kraus

Washington University / UMSL Mechanical Engineering Design Project JME 4110

Our design is a passive solar panel tracker using fundamentals of thermodynamics. A fixed solar tracker only operates at peak efficiency for a short period during the day. Our tracker uses the sun's energy to power pistons that push the panel to face the sun throughout the day, increasing efficiency.

Open Source 3d Printers: An Appropriate Technology For Building Low Cost Optics Labs For The Developing Communities, Jephias Gwamuri, Joshua M. Pearce

Department of Materials Science and Engineering Publications

The recent introduction of RepRap (self-replicating rapid prototyper) 3-D printers and the resultant open source technological improvements have resulted in affordable 3-D printing, enabling low-cost distributed manufacturing for individuals. This development and others such as the rise of open source-appropriate technology (OSAT) and solar powered 3-D printing are moving 3-D printing from an industry based technology to one that could be used in the developing world for sustainable development. In this paper, we explore some specific technological improvements and how distributed manufacturing with open-source 3-D printing can be used to provide open-source 3-D printable optics components for developing world communities …

Pilot Supply At The Regional Airlines: Airline Response To The Changing Environment And The Impact On Pilot Hiring, Becky Lutte

National Training Aircraft Symposium (NTAS)

Regional airlines facing pilot supply challenges have responded to the rapidly changing environment by increasing pay, adjusting lifestyle factors, and enhancing career pathway opportunities. The purpose of this research is to provide a current view of the status of airline hiring at regional airlines, given the changes in pay and other factors, and to explore the impact of increased pay on the airlines ability to meet hiring goals. Data for analysis was collected through interviews of pilot recruiting personnel from the 10 largest regional airlines. Preliminary results reveal that regional airlines are meeting hiring goals but airlines remain significantly challenged …

Incremental Joint Modelling For Dialogue State Tracking, Anh Duong Trinh, Robert J. Ross, John D. Kelleher

Conference papers

Dialogue State Tracking is an important task in dialogue management as it provides a mechanism to monitor dialogue contributions. In this paper we introduce an Incremental Joint Model as a new approach to the task. Our tracker is capable of incrementally tracking Dialogue States. We base our model and analysis on the datasets provided in the Second Dialogue State Tracking Challenge (DSTC2). Our early stage evaluations are based on comparisons of our tracker with both the baseline model provide by the DSTC2 and also LecTrack: a state-of-the-art incremental LSTM-based tracker. The main finding of our experiments is that moving from …

Information Theoretic Study Of Gaussian Graphical Models And Their Applications, Ali Moharrer

LSU Doctoral Dissertations

In many problems we are dealing with characterizing a behavior of a complex stochastic system or its response to a set of particular inputs. Such problems span over several topics such as machine learning, complex networks, e.g., social or communication networks; biology, etc. Probabilistic graphical models (PGMs) are powerful tools that offer a compact modeling of complex systems. They are designed to capture the random behavior, i.e., the joint distribution of the system to the best possible accuracy. Our goal is to study certain algebraic and topological properties of a special class of graphical models, known as Gaussian graphs. First, …

Oblique Wave Scattering By A Submerged Porous Breakwater With A Partially Reflecting Sidewall, Yang Zhao, Hua-Jun Li, Yong Liu

Journal of Marine Science and Technology–Taiwan

This study develops an analytical solution for oblique wave scattering by a submerged porous breakwater with a leeside partially reflecting vertical wall. The matched eigenfunction expansion method is used to develop the analytical solution. The whole fluid domain is divided into three regions according to the geometries of the structures. The series solution of the velocity potential in each region is obtained by the separation of the variables, and the unknown expansion coefficients are determined using the pressure and velocity continuous conditions on interfaces of different regions. The newly developed analytical solution is confirmed by an independently developed multi-domain boundary …

Non-Parametric Identification Of Nonlinear Damping And Restoring Forces For Ship Free Roll Decay In Numerical Tank, Yin Jiang, Ren-Chuan Zhu, Guo-Ping Miao, Ju Fan, Chao Ma

Journal of Marine Science and Technology–Taiwan

Numerical simulations of free roll decay are carried out for the DTMB 5512 based on computational fluid dynamics (CFD) theory and adoption of overset mesh technology. The numerical time history of the ship roll shows good quantitative agreement with the experimental time history in the case of Fr = 0.138 with an angle of list of θa0 = 10°. The natural period is well estimated, there is less than 2% error. According to the time history of the roll angle and the corresponding angular velocity, the nonlinear ship roll damping and restoring force of the hull are identified by solving …

Energy Absorbing Guardrail System, John R. Rohde, John D. Reid, King K. Mak, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A highway crash attenuation system having W - beam rail elements attached to a plurality of vertical posts . An impact terminal with a feeder chute guides one or more of the W - beam rail elements through the impact terminal . The feeder chute has an impact shield extending along a traffic facing side of the chute from an upstream - most end to a downstream - most end of the chute closing the traffic - facing side of the chute . The system also has an anchor cable release mechanism for releasing the cable downstream of the first …