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Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu 2019 Laboratoire des Signaux et Syst`emes (L2S) CentraleSup´elec-CNRS-Universit´e Paris Sud, 3 rue Joliot- Curie 91192 Gif-sur-Yvette cedex, France.

Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper presents a systematic method to analyse the stability of systems with single delay in which the coefficient polynomials of the characteristic equation depend on the delay. Such systems often arise in, for example, life science and engineering systems. A method to analyze such systems was presented by Beretta and Kuang in a 2002 paper, but with some very restrictive assumptions. This work extends their results to the general case with the exception of some degenerate cases. It is found that a much richer behavior is possible when the restrictive assumptions are removed. The interval of interest for the ...


Wyoming Wheels, David Tobin 2018 University of Wyoming

Wyoming Wheels, David Tobin

Honors Theses AY 17/18

Manual wheelchair users traditionally suffer from an increased risk of chronic shoulder injury and the inability to travel quickly or uphill independently. Beginning as a senior design project in fall of 2016, Wyoming Wheels is a geared, lever-action, manual wheelchair system designed to mitigate these challenges. For the 2017-2018 school year, the goal of the project was to create a functional prototype by optimizing the previous year’s project. Specifically, the weight and noise output needed to be decreased, and the shifting, braking, and overall ergonomics of the chair needed to be improved. The total weight of the chair was ...


Design Of Wind Turbine Tower Height And Blade Length: An Optimization Approach, Ryan Wass 2018 University of Arkansas, Fayetteville

Design Of Wind Turbine Tower Height And Blade Length: An Optimization Approach, Ryan Wass

Mechanical Engineering Undergraduate Honors Theses

The wind industry is a fast growing market and is quickly becoming competitive with traditional non-renewable energy resources. As with any developing industry, research must continually be redefined as more complex understandings of design variables are learned. Optimization studies are common ways to quickly refine design variable selections. Historical wind turbine data shows that the tower hub height to rotor diameter ratio scales almost linearly. However there is no specific rule that dictates the optimum hub height for a given diameter. This study addresses this question by using an Excel based optimization program to determine the height to diameter ratio ...


Gnygrens18.Pdf, Garrett Nygren 2018 University of Miami

Gnygrens18.Pdf, Garrett Nygren

Garrett Nygren

The finite element method was used to evaluate microstructural strengthening and toughening effects in nanoparticulate reinforced polymer composites (nanocomposites) and in short aligned discontinuous fiber reinforced polymer composites. Nanoparticulate reinforcement is a well-known method of polymer toughening which can greatly expand the range of engineering applications for polymers. However, the mechanisms of nanoparticulate toughening, as well as complementary sub-micron fracture processes, are not well understood. Short, aligned, discontinuous carbon fiber reinforced thermoplastics show promise as a versatile, inexpensive material system with favorable manufacturability, but failure of the associated morphologies is also not yet well explored.
In nanocomposites, two microstructural effects ...


Hydrodynamics Of An Anguilliform Swimming Motion Using Morison’S Equation, Naga Sasi Devarakonda 2018 University of New Orleans

Hydrodynamics Of An Anguilliform Swimming Motion Using Morison’S Equation, Naga Sasi Devarakonda

University of New Orleans Theses and Dissertations

In this study, the hydrodynamic performance of anguilliform swimming motion is computed using Morison’s equation. This method was shown to predict the servo motor torques well. The anguilliform swimming motion is sinusoidal with increasing amplitude from head to tail. A “wakeless” swimming motion proposed by Vorus and Taravella (2011) with zero net circulation is considered.

This method is compared to the existing slender body theory and is validated with reference to the experimental results of NEELBOT-1.1 (Potts, 2015). The results for the study indicates that self-propulsion speed of the motion is independent of the oscillating tail amplitude at ...


Design Of Selectively Compliant Morphing Wind Turbine Blade Section Using Bistable Laminate For Passive Load Alleviation, Abhishek Chopra, Dr. Andres Arrieta, Janav Udani, Jose Rivas Padilla 2018 Rutgers University - New Brunswick/Piscataway

Design Of Selectively Compliant Morphing Wind Turbine Blade Section Using Bistable Laminate For Passive Load Alleviation, Abhishek Chopra, Dr. Andres Arrieta, Janav Udani, Jose Rivas Padilla

The Summer Undergraduate Research Fellowship (SURF) Symposium

The design of passively controlled compliant morphing structures for large scale wind turbine blades has been of interest due to the inherent advantages of lower mass and reduced complexity over their active counterparts. Previous studies have indicated that embedding a locally bi-stable element within the turbine blade section successfully allows for achieving passive load alleviation. The embedded bi-stable member switches from one stable state to another at a critical aerodynamic load. This local structural change results in a global shift in the aeroelastic response of the blade section. Building on these preliminary results, this research investigates a two- dimensional wind ...


Study Of The Effective Thermal Conductivity Of Polymer Composites With Varying Filler Arrangements, Debraliz Isaac Aragones, Rajath Kantharaj, Aaditya Candadai, Amy Marconnet 2018 University of Central Florida

Study Of The Effective Thermal Conductivity Of Polymer Composites With Varying Filler Arrangements, Debraliz Isaac Aragones, Rajath Kantharaj, Aaditya Candadai, Amy Marconnet

The Summer Undergraduate Research Fellowship (SURF) Symposium

Alternative thermal management solutions for electronic devices are being widely explored due to the increasing heat concentration that results from shrinking sizes and increasing power of modern electronics. Clearly, there is a need to spread the heat effectively in these systems, and polymer composites can potentially provide high thermal conductivity at low filler fraction while maintaining desirable mechanical properties for electronic packaging. The present study aims to investigate the effective thermal conductivity of various copper filler arrangements in a polymer matrix. The polymer composites are fabricated using laser cut acrylic templates to embed aligned copper rods in epoxy and create ...


Micro-Manipulation Using Learned Model, Matthew A. Lyng, Benjamin V. Johnson, David J. Cappelleri 2018 Purdue University

Micro-Manipulation Using Learned Model, Matthew A. Lyng, Benjamin V. Johnson, David J. Cappelleri

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microscale devices can be found in applications ranging from sensors to structural components. The dominance of surface forces at the microscale hinders the assembly processes through nonlinear interactions that are difficult to model for automation, limiting designs of microsystems to primarily monolithic structures. Methods for modeling surface forces must be presented for viable manufacturing of devices consisting of multiple microparts. This paper proposes the implementation of supervised machine learning models to aid in automated micromanipulation tasks for advanced manufacturing applications. The developed models use sets of training data to implicitly model surface interactions and predict end-effector placement and paths that ...


Validation Of Lateral Gap Leakage Objective Function For Use In Multi-Objective Optimization Of Gerotor Pumps, Kevin Cohen, Andrew Robison, Andrea Vacca 2018 Purdue University

Validation Of Lateral Gap Leakage Objective Function For Use In Multi-Objective Optimization Of Gerotor Pumps, Kevin Cohen, Andrew Robison, Andrea Vacca

The Summer Undergraduate Research Fellowship (SURF) Symposium

Gerotor pumps are a common pump choice used in the automotive, agricultural, and construction fields for their low cost and durability. Recently, demanding applications have called for significant design improvements in gear geometry. To address these design challenges, multi-objective optimization has been applied to gear geometry. The goal of this work is to introduce minimizing of lateral-gap leakage to the multi-objective optimization. An objective function for evaluating lateral-gap leakage based on 1D, pressure driven flow is proposed. This simplified approach is compared to CFD simulation solving of Reynolds equation with two pressure boundaries. Comparison of the simplified relation and the ...


Developing An Electromechanical Carbon Dioxide Sensor For Occupancy Monitoring, Joshua L. Jenkins, Allison K. Murray, Jeffrey F. Rhoads 2018 Purdue University

Developing An Electromechanical Carbon Dioxide Sensor For Occupancy Monitoring, Joshua L. Jenkins, Allison K. Murray, Jeffrey F. Rhoads

The Summer Undergraduate Research Fellowship (SURF) Symposium

The Energy Information Administration reported in 2012 that heating and cooling processes consume nearly 35% of the total energy used by commercial buildings. In an effort to limit the amount of energy wasted in conditioning empty buildings and rooms, various occupancy detection techniques have been developed that can be paired with a smart heating, ventilation, and air conditioning (HVAC) control system. This work focused on the development of a novel carbon dioxide detector that is sensitive enough to accurately determine if, and when, a room is occupied. To test the new sensor design, a customized chamber with gas inlets was ...


Waste Heat Recovery From A Vented Electric Clothes Dryer Utilizing A Finned-Tube Heat Exchanger, Abdul Raheem A. Shaik, Stephen L. Caskey, Eckhard A. Groll 2018 Purdue University

Waste Heat Recovery From A Vented Electric Clothes Dryer Utilizing A Finned-Tube Heat Exchanger, Abdul Raheem A. Shaik, Stephen L. Caskey, Eckhard A. Groll

The Summer Undergraduate Research Fellowship (SURF) Symposium

Conventional residential clothes dryers continuously vent moist, hot air during the drying process. The vented air leaves the home but still has useful temperature and humidity that could be recovered to offset other heating demands in the home. A study is carried out to quantify the amount of heat extracted from the waste heat stream of a conventional, vented clothes dryer. To extract the heat, a water cooled, fin-and-tube heat exchanger is located within the exhaust duct. A steady state thermodynamic model was built in Engineering Equation Solver (EES). The model accounts for the heat exchanger’s geometry and applies ...


Universality In Viscous Fluid Spreading And Leveling, Zoë S. Penko, Ivan C. Christov, Daihui Lu 2018 University of Alabama at Birmingham

Universality In Viscous Fluid Spreading And Leveling, Zoë S. Penko, Ivan C. Christov, Daihui Lu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Multiphase fluid flows, or flows where the dynamics of an interface between unlike fluids can be observed, require study to further understand the fundamental relationships of the fluids’ properties and their dynamics in multiple applications. The scope of this research project pertains to low Reynolds number flow, a dense fluid spreading through a less dense ambient fluid, with the spreading fluid movement being driven by gravitational buoyancy forces and density differences. The primary investigation involves studying the spreading and leveling of such fluids in shaped geometries, such as subsurface fractures. The objective is to determine the effect of a wide ...


Development Of Closures For Collisions Between Realistic Particles, Cary Faulkner, Aaron Morris 2018 Purdue University

Development Of Closures For Collisions Between Realistic Particles, Cary Faulkner, Aaron Morris

The Summer Undergraduate Research Fellowship (SURF) Symposium

Systems consisting of solid particles can exhibit fluid-like motion and are common in industrial applications such as pharmaceutical or food processing. Such granular flows are often studied using simulation methods. One common simulation method is the discrete element method (DEM), which solves for the motion of individual particles based on Newton’s laws. However, large-scale particulate systems are difficult to study using DEM due to excessively long simulation times. The goal of this study is to reduce the computational load of these large-scale simulations. Instead of resolving particle trajectories throughout each collision, a scattering function is developed that directly relates ...


Reliability Of Lead-Free Solder Joints Under Combined Shear And Compressive Loads, Ian Bernander, Travis Dale, Yuvraj Singh, Ganesh Subbarayan 2018 Purdue University

Reliability Of Lead-Free Solder Joints Under Combined Shear And Compressive Loads, Ian Bernander, Travis Dale, Yuvraj Singh, Ganesh Subbarayan

The Summer Undergraduate Research Fellowship (SURF) Symposium

In electronic assemblies, solder joints are used to create electrical connections, remove heat, and mechanically support the components. When an electronic device is powered on, the solder joints and the board they are attached to heat up, expanding at different rates. Due to the difference in expansion, shear stress is imposed on the solder joints. As the device is powered on and off, this shear stress can eventually fracture the solder joint, causing the device to fail. Therefore, to increase the lifespan of electronics, it is important to investigate the mechanical properties of solder alloys. The present study investigates how ...


Purdue Air Sense: A Methodology For Improving The Accuracy Of Ambient Aerosol Mass Concentration And Size Distribution Measurement With Low-Cost Optical Sensing Techniques, Rishabh Ramsisaria, Satya Sundar Patra, Brandon Emil Boor 2018 Purdue University

Purdue Air Sense: A Methodology For Improving The Accuracy Of Ambient Aerosol Mass Concentration And Size Distribution Measurement With Low-Cost Optical Sensing Techniques, Rishabh Ramsisaria, Satya Sundar Patra, Brandon Emil Boor

The Summer Undergraduate Research Fellowship (SURF) Symposium

There is a global lack of a means for monitoring air pollutant levels at a local level due to expensive and bulky instrument requirements. It is important to monitor toxic gas levels, as well as particulate matter levels, in the atmosphere to study their effects on human health and to further develop city- and community-level air pollution solutions. In this study, with the means of a Raspberry Pi, low-cost Alphasense Optical Particle Counter and gas sensors, and methodical calibration techniques, we built a portable 3-D printed module powered by clean electricity generated by an on-board Voltaic solar cell that measures ...


Experimental Validation Of A Numerical Phase Change Model For Microchannel Slug Flow Boiling, Christian J. Retter, Todd A. Kingston, Justin A. Weibel, Suresh V. Garimella 2018 Purdue University

Experimental Validation Of A Numerical Phase Change Model For Microchannel Slug Flow Boiling, Christian J. Retter, Todd A. Kingston, Justin A. Weibel, Suresh V. Garimella

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermal management of high-power electronic devices continues to be a critical challenge. Flow boiling in microchannel heat sinks has been demonstrated to be an effective method for removing high heat fluxes from these devices owing to utilization of the latent heat of the fluid and the large surface area enhancement for heat exchange. However, microchannel flow boiling technologies have yet to be broadly implemented due to a lack of experimentally validated prediction and design tools. The goal of this study is to use high-fidelity experimental data to validate a previously developed numerical phase change model, to help enable physics-based prediction ...


Bacteria Movement Near Surfaces, Shulin Wang, Adib Ahmadzadegan, Arezoo Ardekani 2018 Purdue University

Bacteria Movement Near Surfaces, Shulin Wang, Adib Ahmadzadegan, Arezoo Ardekani

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding the behaviors of bacteria near surfaces is crucial in many biological and ecological applications. This knowledge can be used to hinder undesired biofilm formation on medical instruments and wounds. On top of that, it could also provide further insights in biodegradation of dispersed oil. In this work, the behavior of Escherichia Coli near a surface was experimentally studied. We utilized an inverted microscope in the phase filed illumination mode and processed acquired images to track the motions of bacteria near surfaces with high accuracy and repeatability. Distribution of the cells when they reached a steady state shows that the ...


Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev 2018 Purdue University

Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, 110 billion cubic meters of natural gas (primarily methane), a potent greenhouse gas, are flared off for environmental and safety reasons. This process results in enough fuel to provide the combined natural gas consumption of Germany and France. The research team developed a thermophotovoltaic device to convert thermal energy to electricity at a high efficiency using proprietary emitters and combustion system. With the current focus being fuel efficiency and the combustion process, the assembly was simulated using ANSYS Fluent modelling software and the following parameters were optimized: air/fuel ratios, flow rates, and inlet sizes. Simultaneously the heat transfer ...


Predict The Failure Of Hydraulic Pumps By Different Machine Learning Algorithms, Yifei Zhou, Monika Ivantysynova, Nathan Keller 2018 School of Agricultural & Biological Engineering, Purdue University

Predict The Failure Of Hydraulic Pumps By Different Machine Learning Algorithms, Yifei Zhou, Monika Ivantysynova, Nathan Keller

The Summer Undergraduate Research Fellowship (SURF) Symposium

Pump failure is a general concerned problem in the hydraulic field. Once happening, it will cause a huge property loss and even the life loss. The common methods to prevent the occurrence of pump failure is by preventative maintenance and breakdown maintenance, however, both of them have significant drawbacks. This research focuses on the axial piston pump and provides a new solution by the prognostic of pump failure using the classification of machine learning. Different kinds of sensors (temperature, acceleration and etc.) were installed into a good condition pump and three different kinds of damaged pumps to measure 10 of ...


High-Throughput Nanoliter Dispensing Device For Biological Applications, Cole Reynolds, Euiwon Bae Dr., J Paul Robinson Dr. 2018 Purdue University

High-Throughput Nanoliter Dispensing Device For Biological Applications, Cole Reynolds, Euiwon Bae Dr., J Paul Robinson Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Pathogen identification is a field that can contribute largely to the prevention of the spreading of illness and disease. In the past, pathogen identification has been a long and arduous process due to the time-consuming processes and steps that requires technician’s time and effort. With new technologies emerging however, screening of bacteria colonies can be done in a quick and high-throughput way. The problem is that using the current methods, bacteria cannot be transferred to petri dishes fast enough to keep up with the new screening methods. The current study focuses on exploring different methods to create an ergonomic ...


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