Mechanical Engineering Commons^™

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

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

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 ...

The Effects Of Geometric And Stoichometric Change In Nanoparticles And Materials On Lattice Thermal Conductivity, W. Tanner Yorgason

All Graduate Theses and Dissertations

Thermal transport properties are critical for applications ranging from thermal management to energy conversion. Passive thermal management has been an area of study for over a century and has only grown as technology has advanced because it requires no additional energy to remove heat. Changing the nanostructure of the materials involved in passive heat transfer methods, either by geometric changes or stoichiometric changes, can greatly improve the effectiveness of this heat transfer method. In order to explore this further, this work employs LAMMPS molecular dynamics (MD) simulation software to calculate the lattice thermal conductivity (λ_p) of a nanoparticle (NP ...

A Non-Equilibrium Molecular Dynamics Study Of The Effects Of Helium Bubbles On The Thermal Conductivity Of Zrc, Tate Shorthill

All Graduate Plan B and other Reports

Zirconium carbide (ZrC) has been proposed as a potential improvement to nuclear fuel cladding. As such, it is important to characterize its physical properties, particularly those relating to thermal energy transport. Reactor conditions are known to damage fuel microstructure over time. While research has been conducted on undamaged and damaged ZrC, some areas of interest remain. Fission products, such as helium, can accumulate in pores within the fuel microstructure. Such a case has yet to be characterized in ZrC fuel cladding.

A non-equilibrium molecular dynamics model was developed to characterize the thermal properties of ZrC. Fourier’s Law allows the ...

Ultraviolet Diffraction Assisted Image Correlation (Uv-Daic) For Single-Camera 3d Strain Measurement At Extreme Temperatures, Ethan K. Nickerson

All Graduate Theses and Dissertations

Digital Image Correlation (DIC) is a technique which uses images taken before and after deformation to determine displacement and strain data over the surface of the sample. In order to obtain this data for both in-plane as well as out-of-plane direction, multiple views of the sample are required. Typically, this is accomplished using multiple cameras, but it is possible to use diffraction gratings to bend the light coming from the specimen in order to allow a single camera to capture multiple views. This technique is referred to as Diffraction Assisted Image Correlation (DAIC) and has been previously demonstrated at room ...

A Parametric Electrostatic Resonator Using Repulsive Force, Shahrzad Towfighian, Mark Pallay

Mechanical Engineering Faculty Scholarship

In this paper, parametric excitation of a repulsive force electrostatic resonator is studied. A theoretical model is developed and validated by experimental data. A correspondence of the model to Mathieu's Equation is made to prove the existence and location of parametric resonance. The repulsive force creates a combined response that shows parametric and subharmonic resonance when driven at twice its natural frequency. The resonator can achieve large amplitudes of almost 24 μm and can remain dynamically stable while tapping on the electrode. Because the pull-in instability is eliminated, the beam bounces off after impact instead of sticking to the ...

Experimental, Analytical, And Numerical Evaluation Of The Mechanical Properties Of The Brain Tissue, Aref Samadidooki

LSU Doctoral Dissertations

A true understanding of the mechanisms behind most of the brain diseases is still out of reach. For several years, the interest of scientists has been focused on the genetic and biological causes, however, recent studies unraveled the importance of the biomechanics of the brain growth, folding, impact resistance, and deformation on its pathological conditions. While, a wide range of different methods have been used for characterization of the mechanical properties of the brain at the tissue level, the obtained results from different studies are extremely scattered and sometimes in contrast to one another. Since the brain tissue is extremely ...

A Deep Learning Framework To Discern And Count Microscopic Nematode Eggs, Adedotun Akintayo, Gregory L. Tylka, Asheesh K. Singh, Baskar Ganapathysubramanian, Arti Singh, Soumik Sarkar

Plant Pathology and Microbiology Publications

In order to identify and control the menace of destructive pests via microscopic image-based identification state-of-the art deep learning architecture is demonstrated on the parasitic worm, the soybean cyst nematode (SCN), Heterodera glycines. Soybean yield loss is negatively correlated with the density of SCN eggs that are present in the soil. While there has been progress in automating extraction of egg-filled cysts and eggs from soil samples counting SCN eggs obtained from soil samples using computer vision techniques has proven to be an extremely difficult challenge. Here we show that a deep learning architecture developed for rare object identification in ...

An In-Silico Assessment Of Stemless Shoulder Arthroplasty: From Ct To Predicted Bone Response, Jacob M. Reeves

Electronic Thesis and Dissertation Repository

Despite the emergence of stemless humeral implants that utilize short fixation features to gain purchase solely in the metaphysis, the literature contains little information regardingthe morphology and mechanical properties of the humerus’ proximal trabecular-canal, and how stemless implants impact bone response. The present work employs in-silicotools, including CT-based and Finite Element (FE) methods, to define parameters that may influence stemless implant design.

The density and morphology of the proximal humerus were assessed using CT-derived point clouds of the trabecular-canal. Bone density was found to diminish 15-20mm beneath the humeral head resection and was greater peripherally. The depth, path and bounding ...

Solvent-Free Manufacturing Of Electrodes For Lithium-Ion Batteries, B. Ludwig, Z. Zheng, W. Shou, Y. Wang, Heng Pan

Heng Pan

No abstract provided.

The Coupled Photothermal Reaction And Transport In A Laser Additive Metal Nanolayer Simultaneous Synthesis And Patterning For Flexible Electronics, S. Tsai, Y. Liu, Heng Pan, C. Liu, M. Lee

Heng Pan

No abstract provided.

Materials, Mechanics, And Patterning Techniques For Elastomer-Based Stretchable Conductors, X. Yu, B. Mahajan, W. Shou, Heng Pan

Heng Pan

No abstract provided.

Direct Printing Of Microstructures By Femtosecond Laser Excitation Of Nanocrystals In Solution, W. Shou, Heng Pan

Heng Pan

No abstract provided.

Theatrical Turntable, Liam R. Martinez, Isaac Becker, Robert R. Reed, Caroline A. Whelan

Mechanical Engineering

No abstract provided.

Portable Solar Generator For Deployment In Africa, Zachary Chase Cootes, Vivian Mac, Simon Patrick Krauter, Matthew Albert Oatman, Wei(Raymond) Feng Zeng

Mechanical Engineering

No abstract provided.

Theoretical And Experimental Investigation Of Forward Spatter Of Blood From A Gunshot, P. M. Comiskey, A. L. Yarin, Daniel Attinger

Mechanical Engineering Publications

A theoretical model predicting forward blood spatter patterns resulting from a round nose bullet gunshot wound is proposed. The chaotic disintegration of a blood layer located ahead and aside of the bullet is considered in the framework of percolation theory. The size distribution of blood drops is determined, which allows for the prediction of a blood spatter cloud being ejected from the rear side of the target where the bullet exits. Then, droplet trajectories are numerically predicted accounting for gravity and air drag, which is affected by the collective aerodynamic interaction of drops through air. The model predicts the number ...

Chemotherapeutic Drug Cytotoxicity Measurement With A 3d Biomimetic Microfluidic Device And Computational Fluid Dynamics Model, Maryam Moarefian, Caroline Jones, Luke Achenie, Danesh Tafti

Biology and Medicine Through Mathematics Conference

No abstract provided.

Perovskite Solar Cells Fabricated Via Scalable Dip Coating Methods, Joseph F. Iannello

Theses and Dissertations

Perovskite solar cells present the possibility for less expensive electricity generation, through the use of low cost materials and fabrication methods relative to current silicon-based technology. Many current methods of fabricating thin film perovskite solar cells focus on spin-coating, which inherently lacks scalability due to particle conglomeration, poor uniformity over a larger area, and safety concerns. Dip-coating, an alternative to spin-coating, which is explored here addresses these issues which limit scalability. Each individual layer can be separately synthesized, deposited, and characterized, which leads towards scalability. Choosing only the best results from each independent layer allowed progress to the creation of ...

Designing Model Experiments Around Harriet Tubman Middle School, Ryan Crist, Sarah Smith, Greg Sakradse, Ryan Scott, Elliott Gall

Undergraduate Research & Mentoring Program

Air quality is of concern in densely populated areas and especially near sources of inefficiently exhausted fossil fuel such as near the highway. Harriet Tubman middle school in North Portland, Oregon is situated alongside highway 5. Here, model experiments are designed and proposed to observe the instantaneous flow fields reflect modifications. LIDAR data was used to model the school and surrounding topography three-dimensionally in order to construct a model school and surrounding area from laser cut cardboard with a surface smoothed with paper mache. This model will be placed in the Portland State University wind tunnel; transport of mean and ...