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Strong Stability Of A Class Of Difference Equations Of Continuous Time And Structured Singular Value Problem, Qian Ma, Keqin Gu, Narges Choubedar 2018 Nanjing University of Science and Technology

Strong Stability Of A Class Of Difference Equations Of Continuous Time And Structured Singular Value Problem, Qian Ma, Keqin Gu, Narges Choubedar

SIUE Faculty Research, Scholarship, and Creative Activity

This article studies the strong stability of scalar difference equations of continuous time in which the delays are sums of a number of independent parameters tau_i, i = 1, 2, . . . ,K. The characteristic quasipolynomial of such an equation is a multilinear function of exp(-tau_i s). It is known that the characteristic quasipolynomial of any difference equation set in the form of one-delayper- scalar-channel (ODPSC) model is also in such a multilinear form. However, it is shown in this article that some multilinear forms of quasipolynomials are not characteristic quasipolynomials of any ODPSC difference equation set. The equivalence between local strong ...


Characterizing Jetting In An Acoustic Fluidized Bed Using X-Ray Computed Tomography, David R. Escudero, Theodore J. Heindel 2017 Iowa State University

Characterizing Jetting In An Acoustic Fluidized Bed Using X-Ray Computed Tomography, David R. Escudero, Theodore J. Heindel

Theodore J. Heindel

Understanding the jetting phenomena near the gas distributor plate in a fluidized bed is important to gas-solids mixing, heat and mass transfer, and erosion on any bed internals, which can all affect the performance of the bed. Moreover, acoustic vibration in a fluidized bed can be used to enhance the fluidization quality of particulate matter. Characterizing the jetting structure using X-ray computed tomography in a 3D fluidized bed, with and without acoustic intervention, is completed in this study. A 10.2 cm ID fluidized bed filled with glass beads, with material density of 2500 kg/m3 and particles sizes ranging ...


Visualization And Composition Analysis To Quantify Mixing In A Screw Pyrolyzer, Todd A. Kingston, Theodore J. Heindel 2017 Iowa State University

Visualization And Composition Analysis To Quantify Mixing In A Screw Pyrolyzer, Todd A. Kingston, Theodore J. Heindel

Theodore J. Heindel

Characterizing the mixing effectiveness of systems or processes in granular applications is difficult due to ineffective sampling procedures and a lack of quantifiable measurement techniques. The mixing effectiveness of a screw pyrolyzer consisting of a binary mixture of 500–6350 μm red oak chips and 300–500 μm glass beads is evaluated using optical visualization and composition analysis techniques. The mass fraction of binary mixture samples is determined and the weighted sample variance from four outlet ports is used to evaluate the mixing effectiveness. The effect of dimensionless screw pitch on the mixing effectiveness is investigated at levels of p ...


Comparison Of A Virtual Game-Day Experience On Varying Devices, Jack Miller, Holly Baiotto, Anastacia MacAllister, Melynda Hoover, Gabriel Evans, Jonathan Schlueter, Vijay Kalivarapu, Eliot H. Winer 2017 Iowa State University

Comparison Of A Virtual Game-Day Experience On Varying Devices, Jack Miller, Holly Baiotto, Anastacia Macallister, Melynda Hoover, Gabriel Evans, Jonathan Schlueter, Vijay Kalivarapu, Eliot H. Winer

Anastacia MacAllister

Collegiate athletics, particularly football, provide tremendous value to schools through branding, revenue, and publicity. As a result, extensive effort is put into recruiting talented students. When recruiting, home games are exceptional tools used to show a school's unique game-day atmosphere. However, this is not a viable option during the offseason or for off-site visits. This paper explores a solution to these challenges by using virtual reality (VR) to recreate the game-day experience. The Virtual Reality Application Center in conjunction with Iowa State University (ISU) athletics, created a VR application mimicking the game-day experience at ISU. This application was displayed ...


Low-Cost Control Engineering Experiments, Megan Arduin 2017 Western Michigan University

Low-Cost Control Engineering Experiments, Megan Arduin

Honors Theses

The disciplines found within the area of motion and controls is a vital element of each engineer’s education. The ability to understand and then control dynamic systems is a fundamental skill required for many working engineers today. The aim of this project is to further develop the tools and methods available to teach and prepare engineering students to effectively design control system architecture, and then successfully implement their design into real world systems. The main goal is to design an apparatus that can be used to teach control system methods and has an affordable price. There are few experiments ...


Museum Wave Tank Design, David James Streng, Lisa Michelle Dischinger, John Frederick Niemoller 2017 Cal Poly Slo

Museum Wave Tank Design, David James Streng, Lisa Michelle Dischinger, John Frederick Niemoller

Mechanical Engineering

The Santa Maria Discovery Museum would like to add a tsunami wave tank to be one of their demonstrations. The wave tank needs to draw the attention of their young crowd and be educationally informative about the shapes and effects of waves. As this is a museum demonstration for children, the structure, user interface, and wave making mechanism must be durable.

We are a senior project team from California Polytechnic State University that worked on this project with Allan Hancock College and Stanford University. We created waves by rapidly moving a plunger vertically in the water column. This project allows ...


Dyno-Mite Redesign, Brandon Joseph Miller, Daniel Robert Hoffman, Richard DeMedici Young 2017 California Polytechnic State University, San Luis Obispo

Dyno-Mite Redesign, Brandon Joseph Miller, Daniel Robert Hoffman, Richard Demedici Young

Mechanical Engineering

The Cal Poly Mechanical Control Systems Laboratory currently employs an outdated device, known as the Motomatic, to teach students about various motor characteristics and control methods. These include open-loop vs. closed-loop control, speed vs. position control, and DC motor response curves. The current device does not function properly and produces unreliable data due to overwhelming non-linear effects such as stiction and shaft misalignment. Our team was tasked with designing a replacement device that retains many of the same educational goals as the original lab procedure, while also adding new educational goals pertaining to the device system dynamics. The new apparatus ...


Development Of A Rotordynamic Signal Processing Matlab Interface And A Two-Disk Rotor Model, David L. Baker 2017 California Polytechnic State University, San Luis Obispo

Development Of A Rotordynamic Signal Processing Matlab Interface And A Two-Disk Rotor Model, David L. Baker

Master's Theses and Project Reports

Using MATLAB and a National Instruments data acquisition card, a signal processing program meant to monitor the behavior of rotordynamic systems in real-time was developed and tested. By using traditional analysis methods in this field of engineering, commonly desired data representations such as bode, polar, orbit, full spectrum plots were able to be produced to a very high accuracy. Additional capabilities offered by this application are slow roll compensation, synchronous and sub-synchronous filtering, and true three dimensional plotting. The verification of this program was done by comparing the results to the ones acquired with Bently Nevada’s “Automated Diagnostics for ...


Measurement Of Speed Of Sound Profile Using Laaces Balloon, Zhuang Li, Brett Schaefer, Brian Schaefer, William Dever, Tyler Morgan, Matthew Foltz 2017 McNeese State University

Measurement Of Speed Of Sound Profile Using Laaces Balloon, Zhuang Li, Brett Schaefer, Brian Schaefer, William Dever, Tyler Morgan, Matthew Foltz

2017 Academic High Altitude Conference

The goal of this mission is to test the speed of sound at different altitudes and ultimately at a maximum height of 100,000 feet (30 km). In conjunction with this testing, environmental parameters including temperature, pressure, and humidity are measured and used to calculate the speed of sound to compare to the measured results. The team constructed the payload “Dorothy” using polystyrene foam due to its lightweight and thermal isolation property. An ultrasonic sensor with a reflection mirror were installed outside payload box to measure speed of sound. All the sensors were calibrated. Software for the project was developed ...


Cam-Based Pose-Independent Counterweighting For Partial Body-Weight Support In Rehabilitation, Ashish Shinde 2017 University of Nebraska - Lincoln

Cam-Based Pose-Independent Counterweighting For Partial Body-Weight Support In Rehabilitation, Ashish Shinde

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

This thesis presents the design and testing of a body weight support system for gait training in a two-dimensional workspace. Extension of the system to a three-dimensional workspace is not within the scope of this thesis.

Gait dysfunctions are changes in normal walking patterns, often related to a disease or abnormality in different areas of the body. There are numerous body weight support (BWS) systems present in the market which are applied to rehabilitation scenarios in mobility recovery like in gait training. But most of these BWE systems are costly and generally are stationary devices. A major drawback of such ...


Dissertation Xu V1.Pdf, Jiawen Xu 2017 University of Connecticut - Storrs

Dissertation Xu V1.Pdf, Jiawen Xu

Jiawen Xu

The objective of this dissertation research is on the designing and optimization of promising wave guiding and energy manipulation approach.  Specifically address above-mentioned issues of modeling and application of piezoelectric metamaterials and energy harvesting.  The first research task is to develop fundamental modeling and understanding of piezoelectric metamaterial integrated with LC shunts to create local resonances.  We establish the lumped-parameter model of the piezoelectric metamaterial.  Transverse wave is considered throughout the modeling and analysis, and the lumped parameters are derived based on the wavenumber involved.  Taking advantage of the model, we identify the influence of a key parameter, the system-level ...


The Influence Of Macroscale Stress Concentrations On The Near-Resonant Thermomechanics Of Mock Energetic Materials, Lauren A. Cooper, Allison R. Range, Jeffrey F. Rhoads 2017 Western Kentucky University

The Influence Of Macroscale Stress Concentrations On The Near-Resonant Thermomechanics Of Mock Energetic Materials, Lauren A. Cooper, Allison R. Range, Jeffrey F. Rhoads

The Summer Undergraduate Research Fellowship (SURF) Symposium

The characterization of particulate composite energetic materials, both with and without stress concentration, is currently of great interest to the defense community. This work seeks to further characterize the self-heating effect of composite energetic plates, particularly around regions of high stress, when subjected to harmonic excitation near resonance. Mock energetic plates with macroscale stress concentrations are prepared in various compositions based on the PBXN-109 formulation, and are tested near the first resonant frequency using an electrodynamic shaker. The resulting mechanical and thermal responses are recorded using a laser Doppler vibrometer and an infrared camera, respectively. Upon comparison between the regions ...


Generation Of Inhomogeneous Acoustic Waves Using An Array Of Loudspeakers, Samuel E. Wonfor, Trevor A. Kyle, J. Stuart Bolton, Jeffrey F. Rhoads 2017 Purdue University

Generation Of Inhomogeneous Acoustic Waves Using An Array Of Loudspeakers, Samuel E. Wonfor, Trevor A. Kyle, J. Stuart Bolton, Jeffrey F. Rhoads

The Summer Undergraduate Research Fellowship (SURF) Symposium

In previous studies it has been shown that pressure fields created by inhomogeneous sound waves (waves which decay in a direction perpendicular to their propagation direction) are able to transmit energy into objects more effectively than ones created by conventional sound waves. This behavior may be useful in the detection of hidden explosive threats. To explore this, a device capable of constructing inhomogeneous waves is being developed. The proposed device is an acoustic array consisting of several high-frequency speakers. The speakers are independently driven to construct a desired inhomogeneous pressure field on a target surface. Inhomogeneous pressure fields were reconstructed ...


Dynamic Characterization Of Periodic Lattice Of Elastically-Connected Bi-Stable Elements Under Seismic Excitation, Lingwei Meng, Myungwon Hwang, Andres F. Arrieta Ph.D. 2017 Purdue University

Dynamic Characterization Of Periodic Lattice Of Elastically-Connected Bi-Stable Elements Under Seismic Excitation, Lingwei Meng, Myungwon Hwang, Andres F. Arrieta Ph.D.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Metamaterials are engineered materials, typically in periodic arrangements, which exhibit unconventional or extreme properties not found in nature. Understanding the dynamics of metamaterials enables the design of structures with specific functionalities. The dynamics of metamaterials in linear regime has been relatively well studied in recent years, however the unique phenomena arising from nonlinearities in metamaterials are yet to be explored. In this paper, we focus on an array of bi-stable elements connected by elastic springs under various forms of external excitations acting on the entire system. The general equations of motion are derived to handle any degree-of-freedom (DoF) systems of ...


Examination Of Ordering Effects In Sound Evaluations, Yiyun Zhang, Patricia Davies, Daniel Carr 2017 Purdue University

Examination Of Ordering Effects In Sound Evaluations, Yiyun Zhang, Patricia Davies, Daniel Carr

The Summer Undergraduate Research Fellowship (SURF) Symposium

It is difficult to predict sound annoyance responses because annoyance is an inherently subjective concept and the evaluation standard could be different from each person. Usually, annoyance models are functions of strengths of sound characteristics only, and these models can help engineers to improve sounds that machines make and minimize annoyance levels, but other factors can also influence annoyance ratings of products. The main goal of this research was to investigate ordering effects in sound evaluations when people are hearing a set of sounds in sequence. Of particular interest is how the response to a sound influences the response to ...


Stability Analysis Of A Flexible Vehicle Model Controlled By Human Pilot Models, Abhishek Ajmani, Anil Bajaj 2017 Purdue University

Stability Analysis Of A Flexible Vehicle Model Controlled By Human Pilot Models, Abhishek Ajmani, Anil Bajaj

The Summer Undergraduate Research Fellowship (SURF) Symposium

There is a constant race among automobile manufactures to design safer vehicles while minimizing weight to reduce power consumption. Additionally, organizations like NASA and SpaceX are persistently working toward creating reliable, lightweight rovers to be used on the surface of Mars. However, the lightweight requirement often increases vehicle flexibility, which further develops a tendency toward instability in the lateral (sideways) direction. This investigation develops a mathematical model that represents the dynamics of a flexible vehicle in forward motion, and a heuristic human pilot model is proposed which controls the vehicle. Following such formulation, the combined vehicle and pilot model is ...


Cyber-Physical System Characterization And Co-Regulation Of A Quadrotor Uas, Seth E. Doebbeling 2017 University of Nebraska - Lincoln

Cyber-Physical System Characterization And Co-Regulation Of A Quadrotor Uas, Seth E. Doebbeling

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

An Unmanned Aircraft System (UAS) is a Cyber-Physical System (CPS) in which a host of real-time computational tasks contending for shared resources must be cooperatively managed to obtain mission objectives. Traditionally, control of the UAS is designed assuming a fixed, high sampling rate in order to maintain reliable performance and margins of stability. But emerging methods challenge this design by dynamically allocating resources to computational tasks, thereby affecting control and mission performance. To apply these emerging strategies, a characterization and understanding of the effects of timing on control and trajectory following performance is required. Going beyond traditional control evaluation techniques ...


Performance Metrics For Depth-Based Signal Separation Using Deep Vertical Line Arrays, Gabriel Paul Kniffin, John Kenneth Boyle, Lisa Zurk, Martin Siderius 2017 Portland State University

Performance Metrics For Depth-Based Signal Separation Using Deep Vertical Line Arrays, Gabriel Paul Kniffin, John Kenneth Boyle, Lisa Zurk, Martin Siderius

Lisa M. Zurk

A recent publication by McCargar and Zurk [(2013). J. Acoust. Soc. Am. 133(4), EL320–EL325] introduced a modified Fourier transform-based method for passive source depth estimation using vertical line arrays deployed below the critical depth in the deep ocean. This method utilizes the depth-dependent modulation caused by the interference between the direct and surface-reflected acoustic arrivals, the observation of which is enhanced by propagation through the reliable acoustic path. However, neither the performance of this method nor its limits of applicability have yet been thoroughly investigated. This paper addresses both of these issues; the first by identifying and analyzing ...


The Impact Of Three Interfaces For 360-Degree Video On Spatial Cognition, Wutthigrai Boonsuk, Stephen B. Gilbert, Jonathan W. Kelly 2017 Iowa State University

The Impact Of Three Interfaces For 360-Degree Video On Spatial Cognition, Wutthigrai Boonsuk, Stephen B. Gilbert, Jonathan W. Kelly

Jonathan W. Kelly

In this paper, we describe an experiment designed to evaluate the effectiveness of three interfaces for surveillance or remote control using live 360-degree video feeds from a person or vehicle in the field. Video feeds are simulated using a game engine. While locating targets within a 3D terrain using a 2D 360-degree interface, participants indicated perceived egocentric directions to targets and later placed targets on an overhead view of the terrain. Interfaces were compared based on target finding and map placement performance. Results suggest 1) non-seamless interfaces with visual boundaries facilitate spatial understanding, 2) correct perception of self-to-object relationships is ...


X-Ray Flow Visualization Of A Circular Hydraulic Jump, Megan R. DiVall, Theodore J. Heindel 2017 Iowa State University

X-Ray Flow Visualization Of A Circular Hydraulic Jump, Megan R. Divall, Theodore J. Heindel

Theodore J. Heindel

The circular hydraulic jump is a product of the impingement of a vertical, circular jet upon a smooth horizontal surface. Previous studies of this phenomenon have used methods such as electrical contact probes, photography, and lasers to measure various features. This study utilizes X-ray computed tomography (CT) to visualize the circular hydraulic jump; analysis is then completed on the reconstructed 3D image. Time-averaged data of the film thickness before and after the jump and the jump radius, as measured from the X-ray CT images, compare well with available literature. Potential imaging improvements with the current equipment have been identified, particularly ...


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