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Numerical Modeling Of Fluid-Porous Structure Interaction In Arteries, Rana Zakerzadeh, Paolo Zunino 2016 University of Pittsburgh - Main Campus

Numerical Modeling Of Fluid-Porous Structure Interaction In Arteries, Rana Zakerzadeh, Paolo Zunino

Biology and Medicine Through Mathematics Conference

No abstract provided.


Design And Optimization Of Membrane-Type Acoustic Metamaterials, Matthew G. Blevins 2016 University of Nebraska-Lincoln

Design And Optimization Of Membrane-Type Acoustic Metamaterials, Matthew G. Blevins

Architectural Engineering -- Dissertations and Student Research

One of the most common problems in noise control is the attenuation of low frequency noise. Typical solutions require barriers with high density and/or thickness. Membrane-type acoustic metamaterials are a novel type of engineered material capable of high low-frequency transmission loss despite their small thickness and light weight. These materials are ideally suited to applications with strict size and weight limitations such as aircraft, automobiles, and buildings. The transmission loss profile can be manipulated by changing the micro-level substructure, stacking multiple unit cells, or by creating multi-celled arrays. To date, analysis has focused primarily on experimental studies in plane-wave ...


Temporally And Spatially Resolved Quantification Of Hemodynamic Forces And Endothelial Mechanics, Lori M. Lambert 2016 University of Nebraska-Lincoln

Temporally And Spatially Resolved Quantification Of Hemodynamic Forces And Endothelial Mechanics, Lori M. Lambert

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

The endothelium is a thin layer of endothelial cells that line the interior surface of an artery. Due to their direct contact with blood flow, endothelial cells experience varying hemodynamic forces and respond to these forces by altering their morphology. When plaque and other substances accumulate in the walls of arteries, i.e., atherosclerosis, endothelial cells have abnormal responses to blood flow. Studying atherosclerosis progression is, therefore, a two-fold investigation into 1) the hemodynamic forces that cause endothelial responses, and 2) the biological and mechanical responses of endothelial cells. The ultimate goal of this study was to develop an experimental ...


Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang 2016 University of Nebraska - Lincoln

Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang

Lily M Wang

Building services equipment often produces noise signatures with significant tones in them that can lead to complaints in the built environment. Previous studies have investigated prominence levels of assorted tonal frequencies, but it is still unclear what prominence of the tones across varying tonal frequencies can lead to human annoyance. This project seeks to apply two different methods towards defining annoyance thresholds of tones in noise at two tonal frequencies: 125 Hz and 500 Hz. In the first, subjects are asked to perform a task, while exposed to ten minutes of a broadband noise spectrum with a specific level of ...


Assessment Of Noise-Induced Annoyance By Tones In Noise From Building Mechanical Systems, Joonhee Lee, Lily M. Wang 2016 University of Nebraska - Lincoln

Assessment Of Noise-Induced Annoyance By Tones In Noise From Building Mechanical Systems, Joonhee Lee, Lily M. Wang

Lily M Wang

Prominent tones in noise generated by mechanical equipment in buildings can cause complaints from occupants in buildings. The ISO 1996-2 and ANSI S1.13 standards describe methodologies and metrics to quantify tonality perception, but the influence of tones in noise on human annoyance and performance is not fully understood yet. This paper investigates annoyance responses of humans while exposed to background noise with tonal components. Twenty participants completed digit span tasks while exposed to noise signals with differing levels of tones and overall loudness. Subjects were also asked to rate their annoyance after completing tasks under each noise signal. The ...


Assessment Of Noise-Induced Annoyance By Tones In Noise From Building Mechanical Systems, Joonhee Lee, Lily M. Wang 2016 University of Nebraska - Lincoln

Assessment Of Noise-Induced Annoyance By Tones In Noise From Building Mechanical Systems, Joonhee Lee, Lily M. Wang

Lily M Wang

Prominent tones in noise generated by mechanical equipment in buildings can cause complaints from occupants in buildings. The ISO 1996-2 and ANSI S1.13 standards describe methodologies and metrics to quantify tonality perception, but the influence of tones in noise on human annoyance and performance is not fully understood yet. This paper investigates annoyance responses of humans while exposed to background noise with tonal components. Twenty participants completed digit span tasks while exposed to noise signals with differing levels of tones and overall loudness. Subjects were also asked to rate their annoyance after completing tasks under each noise signal. The ...


Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang 2016 University of Nebraska - Lincoln

Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang

Lily M Wang

Building services equipment often produces noise signatures with significant tones in them that can lead to complaints in the built environment. Previous studies have investigated prominence levels of assorted tonal frequencies, but it is still unclear what prominence of the tones across varying tonal frequencies can lead to human annoyance. This project seeks to apply two different methods towards defining annoyance thresholds of tones in noise at two tonal frequencies: 125 Hz and 500 Hz. In the first, subjects are asked to perform a task, while exposed to ten minutes of a broadband noise spectrum with a specific level of ...


Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang 2016 University of Nebraska - Lincoln

Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang

Lily M Wang

Building services equipment often produces noise signatures with significant tones in them that can lead to complaints in the built environment. Previous studies have investigated prominence levels of assorted tonal frequencies, but it is still unclear what prominence of the tones across varying tonal frequencies can lead to human annoyance. This project seeks to apply two different methods towards defining annoyance thresholds of tones in noise at two tonal frequencies: 125 Hz and 500 Hz. In the first, subjects are asked to perform a task, while exposed to ten minutes of a broadband noise spectrum with a specific level of ...


Effects Of Room Acoustics On Comprehension Of Foreign-Accented Speech By Native And Non-Native English-Speaking Listeners, Zhao Peng, Kristin E. Hanna, Brenna N. Boyd, Lily M. Wang 2016 University of Nebraska - Lincoln

Effects Of Room Acoustics On Comprehension Of Foreign-Accented Speech By Native And Non-Native English-Speaking Listeners, Zhao Peng, Kristin E. Hanna, Brenna N. Boyd, Lily M. Wang

Lily M Wang

In a previous study by the authors, reverberation time (RT) and background noise level (BNL) were both found to have negative effects on native and non-native English-speaking listeners in comprehending English speech produced by native American-English-speaking talkers. Comprehension scores were adjusted for listeners’ baseline English proficiency levels. In the present study, instead of native English-speaking talkers, two native Mandarin Chinese talkers (one male, one female) with similar English spoken proficiency were recruited to produce the same speech materials used in the previous study. A similar methodology was adopted to conduct speech comprehension tests on three groups of listeners: 1) native ...


Quantification And Subjective Perception Of Varying Reflection Densities In Measured Room Impulsed Responses, Hyun Hong, Lily M. Wang 2016 University of Nebraska - Lincoln

Quantification And Subjective Perception Of Varying Reflection Densities In Measured Room Impulsed Responses, Hyun Hong, Lily M. Wang

Lily M Wang

This project focuses on quantifying and testing the subjective perception of reflection densities, or the number of reflections per second, from different room impulse responses. The widely used room acoustic metric, reverberation time, is linked to the perceived reverberation in a room. Two different rooms having the same reverberation time, though, can have different reflection densities in their room impulse responses, and this difference in reflection density may affect how listeners perceive spatial impression in rooms. To investigate how sensitive humans are to a change of reflection density, this paper first reviews assorted parameters for quantifying reflection density from measured ...


Biomolecular Interactions Control The Shape Of Stains From Drying Droplets Of Complex Fluids, Cedric Hurth, Ranjeesh Bhardwaj, Sahar Andalib, Christophe Frankiewicz, Andrew Dobos, Daniel Attinger, Frederic Zenhausern 2016 University of Arizona

Biomolecular Interactions Control The Shape Of Stains From Drying Droplets Of Complex Fluids, Cedric Hurth, Ranjeesh Bhardwaj, Sahar Andalib, Christophe Frankiewicz, Andrew Dobos, Daniel Attinger, Frederic Zenhausern

Daniel Attinger

When a sessile droplet of a complex fluid dries, a stain forms on the solid surface. The structure and pattern of the stain can be used to detect the presence of a specific chemical compound in the sessile droplet. In the present work, we investigate what parameters of the stain or its formation can be used to characterize the specific interaction between an aqueous dispersion of beads and its receptor immobilized on the surface. We use the biotin-streptavidin system as an experimental model. Clear dissimilarities were observed in the drying sequences on streptavidin-coated substrates of droplets of aqueous solutions containing ...


Texture And Wettability Of Metallic Lotus Leaves, Christophe Frankiewicz, Daniel Attinger 2016 Iowa State University

Texture And Wettability Of Metallic Lotus Leaves, Christophe Frankiewicz, Daniel Attinger

Daniel Attinger

Superhydrophobic surfaces with the self-cleaning behavior of lotus leaves are sought for drag reduction and phase change heat transfer applications. These superrepellent surfaces have traditionally been fabricated by random or deterministic texturing of a hydrophobic material. Recently, superrepellent surfaces have also been made from hydrophilic materials, by deterministic texturing using photolithography, without low-surface energy coating. Here, we show that hydrophilic materials can also be made superrepellent to water by chemical texturing, a stochastic rather than deterministic process. These metallic surfaces are the first analog of lotus leaves, in terms of wettability, texture and repellency. A mechanistic model is also proposed ...


Improving Radiation And Stress Corrosion Cracking Resistance Of Austenitic Stainless Steels By Laser Shock Peening, Qiaofeng Lu 2016 University of Nebraska-Lincoln

Improving Radiation And Stress Corrosion Cracking Resistance Of Austenitic Stainless Steels By Laser Shock Peening, Qiaofeng Lu

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

Structural alloys for Generation-IV nuclear reactors need to endure a high neutron dose, high temperature, and corrosive coolant. Austenitic stainless steels, particularly the oxide-dispersion-strengthened (ODS) austenitic steels, are promising candidate materials, but they suffer several limits such as irradiation damage and stress corrosion cracking (SCC). This research applies a laser shock peening (LSP) process to improve the radiation and SCC resistance of austenitic stainless steels in simulated nuclear reactor environments. A high density dislocation networks, stacking faults and twin boundaries were generated in the surface region of 304 steels by the shock wave-material interactions in the LSP process. In-situ TEM ...


Automated Mini-Channel Platform For Studying Plant Root Environments, Kevin F. Kreis 2016 University of Nebraska-Lincoln

Automated Mini-Channel Platform For Studying Plant Root Environments, Kevin F. Kreis

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

Plants are crucial to our lives; they provide us with building materials, oxygen, and food. A season’s crop yield can be significantly affected by local environmental factors. Farming practices currently focus on using fertilizer, pesticides, monitoring water availability, and genetic modification of the plant to increase crop yield. Improving fundamental understanding of plant root interactions with their local soil environment, or rhizosphere, will help improve crop yield. Studying such interactions is challenging because roots are underground, making it difficult to observe interactions and to manipulate the local soil environment.

The goal of this thesis is to develop an automated ...


Experimental Investigation Of The Melting Behavior And The Transient Heat Transfer In A Phase Change Material (Pcm), Mohammad A. Bashar 2016 The University of Western Ontario

Experimental Investigation Of The Melting Behavior And The Transient Heat Transfer In A Phase Change Material (Pcm), Mohammad A. Bashar

Electronic Thesis and Dissertation Repository

Phase change materials (PCMs) used in thermal energy storage (TES) system as heat storage media can play crucial role in various engineering applications. PCMs have the inherent ability to store large amount of heat by exploiting their heat of fusions, predominantly during their solid-liquid phase-change period. The present study reports an experimental investigation on the melting process in a PCM and the associated heat transfer in a transient manner. The experiments were conducted in a rectangular chamber filled with paraffin wax used as the PCM and, a cylindrical copper tube with different geometries and orientations as the heat source.

The ...


Design Of Medical Devices For Diagnostics In The Gastrointestinal System, Charles R. Welch 2016 University of Nebraska-Lincoln

Design Of Medical Devices For Diagnostics In The Gastrointestinal System, Charles R. Welch

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

This thesis presents the design, controls, and testing of two systems: a novel colonoscope locomotion design for diagnostics, and a biosensor capsule that implants a sensor in the small intestine. Each system requires special design considerations for use in the gastrointestinal system.

Colonoscopy procedures are recommended as a screening for colon cancer and related conditions after the age of 50. The need for an improved colonoscope that reduces the colonoscopy time and patient discomfort is apparent. The semi-autonomous device presented here could likely reduce the colonoscopy procedure time by allowing the physician to focus more on the diagnosis and less ...


Spinal Implant Design And Subsidence, Schuyler E. Price, Lorrin Schoeneweis, Hannah Steele, Matthew Shomper, Timothy L. Norman 2016 Cedarville University

Spinal Implant Design And Subsidence, Schuyler E. Price, Lorrin Schoeneweis, Hannah Steele, Matthew Shomper, Timothy L. Norman

The Research and Scholarship Symposium

A spinal implant may be used in people who have diseased or injured intervertebral discs pushing against their spinal cord and nerves, causing them loss of sensation due to nerve impingement. Patients who have not found relief through non-surgical means may require a discectomy, which removes the disc and relieves the pressure. There are several ways to then fill the resulting gap which include fusion devices, artificial disc replacement (ADR) devices, or bone grafts. Our study focused on the first two mechanical options.

Subsidence, or the vertical movement of the device into the adjacent vertebral bodies, is an often reported ...


Squeaver, Cole Stonebrook, Matthew Frana, Samuel Tabor 2016 University of Tennessee - Knoxville

Squeaver, Cole Stonebrook, Matthew Frana, Samuel Tabor

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Overhanging limbs pose a threat to many homeowners with trees in their yard. If these limbs fall, property damage and personal injury are a major possibility. Currently the two methods used to cut and remove these limbs are hiring a tree service to use a boom truck to lift an arborist up to the limb or having a tree climber cut and lower the limb. Both methods are unsafe and expensive. Our design will be a tree-trimming device that can be rented from an equipment rental facility and operated by the homeowner. The machine will have the capability to extend ...


Leidenfrost Energy Barriers, James Peck, Anton Hassebrook, Craig Zuhlke, Troy Anderson, Dennis Alexander, George Gogos, Sidy Ndao 2016 University of Nebraska - Lincoln

Leidenfrost Energy Barriers, James Peck, Anton Hassebrook, Craig Zuhlke, Troy Anderson, Dennis Alexander, George Gogos, Sidy Ndao

UCARE Research Products

In this work, an “Energy Barrier” was created to control the motion of Leidenfrost droplets. This barrier was created by functionalizing a portion of a mirror-polished stainless steel 304 surface with Femtosecond Laser Surface Processing (FLSP). FLSP results in superhydrophilic, hierarchical, micro- and nanostructures which are highly wetting and thus have an increased Leidenfrost temperature. Water droplets in the film boiling state were deposited, and propelled by gravity towards the Energy Barrier interface. Room temperature droplets were deposited over a range of surface temperatures beginning with the Leidenfrost temperature of mirror-polished stainless steel 304 and culminating at the Leidenfrost temperature ...


Premixed Charge Of N-Butanol Coupled With Direct Injection Of Biodiesel For An Advantageous Soot-Nox Trade-Off, Valentin Soloiu, Marvin Duggan, Henry Ochieng, Spencer Harp, Jabeous Weaver, Craig Jekins, Brian Vlcek 2016 Georgia Southern University

Premixed Charge Of N-Butanol Coupled With Direct Injection Of Biodiesel For An Advantageous Soot-Nox Trade-Off, Valentin Soloiu, Marvin Duggan, Henry Ochieng, Spencer Harp, Jabeous Weaver, Craig Jekins, Brian Vlcek

Valentin Soloiu

In this study, a direct injection (DI) compression ignition engine fueled with biodiesel was supplemented with n-butanol port fuel injection (PFI) in order to simultaneously reduce in cylinder nitrogen oxides formation, decrease soot and favorable modify their trade-off. The combustion and emission characteristics were investigated for regimes of 1-5 bars IMEP at 1400 rpm. By applying this methodology, for the regimes in which the n-butanol PFI was applied, the premixed charge combustion has been split into two regions of high temperature heat release, an early one, BTDC, and a second stage ATDC, oxidizing the soot formed from biodiesel combustion and ...


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