Engineering Commons^™

Thermal Atomic Layer Etching Of Mos2 Using Mof6 And H2O, Jake Soares, Anil U. Mane, Devika Choudhury, Steven Letourneau, Steven M. Hues, Jeffrey W. Elam, Elton Graugnard

Materials Science and Engineering Faculty Publications and Presentations

Two-dimensional (2D) layered materials offer unique properties that make them attractive for continued scaling in electronic and optoelectronic device applications. Successful integration of 2D materials into semiconductor manufacturing requires high-volume and high-precision processes for deposition and etching. Several promising large-scale deposition approaches have been reported for a range of 2D materials, but fewer studies have reported removal processes. Thermal atomic layer etching (ALE) is a scalable processing technique that offers precise control over isotropic material removal. In this work, we report a thermal ALE process for molybdenum disulfide (MoS₂). We show that MoF₆ can be used as …

Effects Of Feeding Mode On The Performance, Life Span And Greenhouse Gas Emissions Of A Vertical Flow Macrophyte Assisted Vermifilter, Rajneesh Singh, Chittaranjan Ray, Daniel N. Miller, Lisa M. Durso, Yulie Meneses, Shannon Bartelt-Hunt, Matteo D’Alessio

Faculty and Student Publications

This study was conducted to investigate the impact of intermittent feeding on performance, clogging, and gaseous emission on macrophyte assisted vermifiltration (MAVF) based treatment system. Synthetic slaughterhouse wastewater was applied to two different integrated vertical flow based MAVFs. Triplicates were used throughout the study. Eisenia fetida earthworms were added to MAVFs, and Carex muskingmenis plants were planted. Wastewater was applied to the reactors on 1) intermittent (8 h/day) (IMAVF) and 2) continuous (24 h/day) (CMAVF) basis. The average chemical oxygen demand, total nitrogen, and total phosphorous removals achieved by the IMAVF were 80.2 ± 1.6%, 53.9 ± 1.3% and 66.5 …

2022 Fall Engr333 Poster, Section A, Dat Cao, Izuchi Ebeku, Samuel Hoover, Sawyer Masselink, Ian Vanderkooi, Matthew Carlson, Jacob Heeres, Anthony Nykamp, Jacob Vanwyngarden, Nate Anderson, Anna Giboney, Gia Mien Le, Jonathan Washburn, Jess Camp, Ryan Macintyre, Aubree Peters, Alin Stoica, Drew Stoneburner, Claire Sheppard, Alayna Spiering, Reid Veneman, James Viel

ENGR 333

In 2017 President Michael K. Le Roy signed Second Nature’s President Climate Commitment. This commitment outlines that Calvin’s governing body will ensure Calvin University is a carbon neutral educational institution by 2057. In June of 2022, Calvin University’s presidential seat was passed from Dr. Michael K. Le Roy to Dr. Wiebe Boer. In his short time as the president of Calvin University, Dr. Boer has put many projects into motion to help Calvin achieve its goal of becoming carbon neutral by 2057. This past fall Dr. Boer tasked the ENGR 333 class with answering the following question: What would it …

Thermal Effect On Dislocation Interactions In Magnesium Alloy, Yuzhi Zhu, Yi Chen, Dewen Hou, Zidong Wang

Materials Science and Engineering Faculty Publications and Presentations

In this work, dislocation interactions are directly observed and analyzed by using in-situ transmission electron microscope during heating processes in a pre-deformed Mg-3Al-1Zn magnesium alloy. Thermodynamic behaviors of two types of dislocations are investigated, i.e., individual dislocations and low-angle grain boundary arranged by dislocations. The results show that the low-angle grain boundary remains stable as the heating temperature increases to 673 K, while most of the individual dislocations disappear until the heating temperature reaches 473 K. Furthermore, the low-angle grain boundary tends to absorb individual dislocations nearby. The stability and the annihilation of both types of dislocations are discussed.

An Ultrasensitive Bacterial Detection Platform For Culture-Free Diagnosis Of Infections, Xuyang Shi

ETD Archive

The current methods of the diagnosis of bloodstream infections are based on bacterial culture growth, a process that requires considerable time, e.g., 12-16 hours, to obtain a result. This long wait time for the result creates many problems, including the generation of multi-drug resistant organisms (MDROs). At the same time, infected bloodstream usually contains a very low concentration of bacteria, i.e., lower than 5 CFU/mL. The long diagnosis time and the extremely low concentration of bacteria in the infected bloodstream make such infections difficult to diagnose. Here, we demonstrate a culture-free approach for the diagnosis of bloodstream infections using a …

Utilizing Simulated Vehicle Trajectory Data From Connected Vehicles To Characterize Performance Measures On An Arterial After An Impactful Incident, Norris Kamugisha Novat Baraba

ETD Archive

Traffic incidents are unforeseen events known to affect traffic flow because they reduce the capacity of an arterial corridor segment and normally generate a temporary bottleneck. Identification of retiming requirements to enhance traffic signal operations when an incident occurs depends on operations-oriented traffic signal performance measurements. When effective and real-time traffic signal performance metrics are employed at traffic control centers, delays, fuel use, and air pollution may all be decreased. The majority of currently available traffic signal performance evaluations are based on high-resolution traffic signal controller event data, which gives data on an intersection-by-intersection basis but requires a substantial upfront …

Lipids Affect The Diffusion Of Estradiol In Osteonal Bone, Nicholas Anthony Cimino

ETD Archive

In healthy osteonal bone, embedded osteocytes form an intercellular communication network through overlapping cell membrane extensions, possibly defining an overlooked and clinically relevant lipid-mediated transport pathway for nonpolar molecules. Previous techniques evaluating solute transport in cortical bone limit tissue analysis to microscale areas (less than 1 mm2) using tracers and assumptions that diminish clinical relevance, presenting the need for an improved method to evaluate solute diffusion in macroscale areas (greater than 1 mm2) of osteonal bone. A new diffusion system - constructed of glass and polytetrafluoroethylene - was designed and validated for this purpose, exhibiting minimal adsorption of solutes and …

Development And Control Of A Pediatric Lower Limb Exoskeleton For Gait Guidance, Anthony Clarence Goo

ETD Archive

Several genetic, developmental and neurological disorders can cause various levels of gait impairment in the pediatric population. Powered lower limb orthoses, or exoskeletons, have recently been used to address gait impairment and afford therapists alternative solutions and strategies for gait therapy. Most exoskeleton research has focused on the adult population while the pediatric population remains underserved. The limitations of current pediatric exoskeletons make them impractical for use in both community and clinical settings. Furthermore, exoskeleton controllers suitable for these environments should promote human volitional control while guiding the subject towards a dynamically stable healthy gait pattern.

This dissertation presents the …

Interdisciplinary Design Studio: Programming Document Visioning For A Robotic Demonstration, Research, And Engagement Dairy, Steve(N) Hardy, Nate Bicak, Sarah Alduaylij, Noor Al-Maamari, Devyn Beekman, Kelsey Belgum, Lauren Chubb, Nicholas Forte, Mitchell Hill, Joshua Holstein, Dylan Lambe, Phuong Le, Mia Leriger, Elizabeth Loftus, Josh Lorenzen, Megan Lovci, Alex Martino, Zade Miller, Hannah Morgan, Annabelle Nichols, Collin Shearman, Rebecca Sowl, Nalin Theplikhith, Angela Vu, Shaylee Wagner, Ethan Watermeier, Trever Zelenka

Architecture Program: Student Creative Activity

The 2022 COLLABORATE Design Studio brought together students from various disciplines to address a complex, real-world project which required collaborative input from different perspectives. The studio worked to advance the co-creation of knowledge between external stakeholders, students, and instructors. The course was co-taught by faculty from different disciplines, and areas of expertise. During the semester, Nate Bicak and Steven Hardy worked with students from Architecture and Interior Design in collaboration with students in Dr. Tami Brown-Brandl’s students in Biological Systems Engineering and Animal Science to explore the values, spatial qualities, and area requirements of a Robotic Demonstration, Research, and Engagement …

In-Situ Tribology Of Engineered Surfaces With 3d-Printed Micro/Nano-Textures, Mahyar Afshar Mohajer

Graduate Theses and Dissertations

Surface texturing is an effective way to reduce the adhesion and friction between two contacting surfaces by reducing the real area of contact between them, providing a potential solution for adhesion and friction-induced failures, for example, failures in micro-/nano-electromechanical systems (MEMS/NEMS). Surface texturing is also essential to the realization of functional surfaces such as superhydrophobic/philic and icephobic surfaces. However, textures are prone to deformation due to being subjected to higher contact pressures. The advancement of 3D nanoprinting by two-photon lithography (TPL), combined with the ability to make an in-situ observation of the interplay between the forces and the sliding surfaces …

Evaluating Arkansas Weathering Steel Bridge Performance, Yessenia Gonzalez

Graduate Theses and Dissertations

Weathering steel enhances corrosion-resistant steel features over conventional steel when a patina properly forms on the weathering steel surface. Weathering steel is a low carbon steel of less than 0.3% carbon by weight and has a chemical composition including other alloying elements such as nickel, copper, and chromium that develops a patina. The patina is a dense protective oxide film layer that develops on the steel member surface. The patina defends the steel from corrosion by preventing moisture, oxygen, and contaminant penetration. However, long periods of moisture and deicing chemicals applied during wet wintry conditions hinder proper patina formation. Without …

Interfacial Engineering Of Nickel-Rich Layered Oxide Cathodes Via Atomic Layer Deposition (Ald), Xin Wang

Graduate Theses and Dissertations

Layered nickel-rich cathodes LiNixMnyCozO2 (NMCs, x + y + z =1, x ≥ 0.6) are regarded as one of the most promising cathode materials for next-generation lithium-ion batteries (LIBs), given their remarkably reduced cost and increased capacity compared to the conventional LiCoO2 cathode. However, the deployment of these Ni-rich cathodes has been hindered by the continuous loss of practical capacity and reduction in average working voltage, inherently due to their interfacial, structural, and thermodynamic instability. To address these issues, interfacial engineering via surface modification has been well-recognized as an effective strategy and a large number of coating materials have been …

Improving Building Cfd Peak Pressure Computation Using Les With A Focus On Inflow Turbulence Methods And Grid Spacing Size., Zahra Mansouri

Graduate Theses and Dissertations

Structural failures by extreme winds often leads to economic losses and even deaths. Proper design of buildings requires accurate estimation of wind loads to prevent structural damage. Using routine guidelines generally leads to the underestimation of buildings’ peak pressures, in which most failures occur. To estimate wind loads more accurately three different methods (i.e., field measurement, wind tunnel (WT), and computational fluid dynamics (CFD)) are in use. A well-validated CFD provides more flow field details at lower costs compared to field measurements and WT. As strong winds are extremely turbulent, the effects of turbulence in wind should be incorporated into …

2022 Fall Engr333 Project Section B Final Report, Nicholas Paternoster, Nick Grossman, Jared Ruba, Zac Runhaar, Caleb Styf, Anne Ghata, Micah Lee, Thomas Noble, Liam Austin, Kai Barboza, Mark Bekhet, Jordan Tuter, Jacob Tanis, Sara Vansolkema, Aidan Bakker, Ben Casey, Sarah Mccarthy, Elise Miera, Christine Vanoyen

ENGR 333

Sustainability is a multi-faceted grand challenge. One of today’s largest challenges is related to sustainability: CO2 emissions from energy consumption. Calvin University purchases natural gas for the energy services it provides; however, it is a major contributor to the amount of CO2 emitted into the atmosphere. The ENGR 333 section B class was tasked with the question: What would it take to eliminate Calvin’s natural gas-related net CO2 emissions? After many hours of research and calculations, the ENGR 333 section B class answered this question with recommendations such as implementing ground source heat pumps, console heat pumps, air source heat …

Conceptual Design Level Airframe/Propulsion Integration Using The Generic Synthesis Framework Avds., Harinkumar Patel

Mechanical and Aerospace Engineering Dissertations - Archive

In the past few decades there has been a significant growth in commercial aerospace transportation encompassing both atmospheric and space flight. In fact, the aircraft industry has seen several generations of engines and vehicles developed. While the space launch sector has switched from exclusively expandable rockets systems to including reusable rocket systems. Now, the current push in the industry is to develop a reusable in-atmosphere hypersonic transportation system. The development of any aircraft entails communicating the interactions among the principal design disciplines (aerodynamics, propulsion, structures, materials, etc.). For hypersonic vehicles, the interdependence of these interactions is enhanced to a level …

Robust Synthesis Methods For Cooperative Systems, Baris Taner

Mechanical and Aerospace Engineering Dissertations - Archive

Cooperative systems, like any other dynamic systems, suffer in performance because of uncertainty yet there is an added layer of uncertainty due to the communication among agents. Therefore, analytic solution to these problems are hard if not impossible. With the advancements in the linear and non-linear methods, i.e. linear matrix inequalities (LMI) and non-linear transformations, robust performance analysis and controller synthesis for cooperative systems can be reformulated as optimization problems with LMI constraints as has been done in the last two decades. Another aspect of the problem becomes visible as the cooperative system grows larger and that necessitates faster solution …

Effect Of Centrifugal Force On The Load Capacity Of Thrust Gas Bearing, Rakan Mohammed Haidar

Mechanical and Aerospace Engineering Theses - Archive

It has been known for many decades that both rigid and foil thrust bearings are two options in the market for high-speed turbomachinery systems. Their advantages encompass the lower manufacturing cost, the lighter weight, and the flexibility in allowing “component misalignment and runout.” When the operating fluid is air, the classical lubrication theory works perfectly. Any additional terms of the inertia effect might be somehow less significant and sometimes negligible since the viscous forces will be dominant, but this may not be the case if the bearing operates in a harsh environment, such as a high-pressure environment. Nonetheless, this is …

Energy Analysis Of Rear Door Heat Exchangers In Data Centers With Dynamic Workload Distribution, Sai Abhideep Pundla

Mechanical and Aerospace Engineering Theses - Archive

In recent years, applications including IoT (Internet of Things), content delivery, and 5G have created a large demand for low-latency access to data processing and data storage. Traditional centralized data centers weren’t designed with those use cases in mind. Small data centers such as edge computing data centers and colocation data centers house more than half of all servers across the United States. Rear Door Heat exchangers (RDHx) provide an energy-efficient cooling solution to traditional CRAC/CRAH - based cooling methods by localizing the heat removal from the rack. With more control over air distribution through a shorter path between the …

Numerical Analysis Of Hybrid Server Immersed In Synthetic Dielectric Fluid, Bhavana Reddy Mandadi

Mechanical and Aerospace Engineering Theses - Archive

In recent years there has been a phenomenal development in cloud computing, networking, virtualization, and storage, which has increased the demand for data centers. With this increase, there is a demand for higher CPU (Central Processing Unit) performance and an increase in the Thermal Design Power (TDP). Maintaining the CPU temperature within the specified parameters for air-cooled servers is a challenge in thermal engineering (due to performance). One of the components of the Data Centers with the largest energy consumption is the cooling system, which uses over 40% of the energy. Advancements in DRAMs and the increased support of CPUs …

Conceptual Gas Turbine Hybrid Engine Design For High Speed Rail Locomotive Propulsion, Frank Roger Tennyson

Mechanical and Aerospace Engineering Theses - Archive

The modern experimental jet train developed by Bombardier Transportation was designed to partner with the present day electrified Acela high speed trains. The Jet train would provide transportation to areas (Rural etc.), as well as transcontinental capabilities to existing towns and cities where electrified propulsion units are not feasible. The Bombardier Jet Train utilizes petroleum-based fuel, diesel engine power, and multiple turboshaft engines, for higher speeds. The Pratt and Whitney PW150 engine design parameters will be used to develop the Conceptual Hybrid Turbo Shaft Engine (CHTS). The newer Conceptual Hybrid Turbo Shaft Engine (CHTS) should increase engine performance, lower specific …

Thermally Charging Capacitor: A New Protocol To Accurately Measure The Thermoelectric Potential, Amit Phalak

Mechanical and Aerospace Engineering Theses - Archive

Harvesting energy from waste heat would benefit in creating sustainable systems. Specifically, thermoelectric energy conversion can be used for low-grade waste heat recovery. However, the efficiency of conventional solid-state (i.e., semiconductor) has reached to the upper limit and could not make any advancement for more than 30 years. As a paradigm shift from solid-state thermoelectric conversion, in this study, ionic thermoelectric phenomena in liquid are explored. An electrolyte, with disproportionate size of anions and cations, when subjected to a temperature gradient can experience induced ion separation. In the phenomenon known as “Soret effect”, the smaller ions with higher mobility move …

An Integrated Design Tool For Tow-Steered Composite Laminate In Abaqus, Twinkle Kothari

Mechanical and Aerospace Engineering Theses - Archive

The material of choice for contemporary aircraft and its component design over the past few decades has shifted more and more toward fiber-reinforced composites. This is mainly due to the improved strength, lightweight, corrosion resistance, design flexibility, and durability of composites over traditional metals. Advanced tailorable composites such as tow-steered composites can be designed and fabricated with fibers following prescribed curvilinear paths, which provides improved mechanical performance compared with unidirectional fiber-reinforced composites (UDFRCs). However, the potential of tow-steered composites oftentimes fails to be exploited due to the lack of design tools. Currently, there are no commercially available design tools for …

Physical Modeling Of Filament Growth And Resistive Switching In Metal Oxide-Based Rram, Kena Zhang

Material Science and Engineering Dissertations - Archive

Metal oxide-based resistive random-access memories (RRAM) exhibit several excellent performances, such as nanosecond switching speed, large write-erase endurance, and long retention time, and can potentially replace the traditional circuit elements for use as the fundamental units in next-generation hardware deep-learning or neuromorphic systems. The functionality of a metal oxide-based RRAM is attributed to an oxygen vacancy (V_O^(..))-rich conductive filament (CF), which initially forms, and later dissolves or regrows inside the oxide layer during the resistive switching process. However, the complicated interplays among the coexisting chemical, electrical, mechanical, and thermal effects during the formation, growth, and rupture of the CFs make …

Effects Of Graphene In High-Density Polyethylene Microfibers, Ashish Lal Sivadas Anilal

Material Science and Engineering Theses - Archive

High-Density Polyethylene uniquely can induce banded spherulites as it is crystallized from its melt. We studied the effects of graphene in the crystallography of banded HDPE by examining parameters such as the extent of twisting, spherulitic growth, and nucleation density. The application of graphene as a multifunctional filler in polymer matrices is a great topic of interest because graphene at low concentrations can bring many improvements in mechanical, electrical, and thermal properties. We synthesized graphene oxide by chemical oxidation of graphite and further studied its effects in the twisted crystallography of HDPE. Three batches of fibers were extruded: two batches …

Sub-10k Cold-Electron Injection To Silicon At Room Temperature, Ojas Tushar Bhayde

Material Science and Engineering Theses - Archive

The Fermi-Dirac thermal excitation of electrons results in unwanted off-state leakage currents in metal-oxide-semiconductor field-effect transistors (MOSFETs), leading to excessive power consumption in modern electronic devices. The electron thermal excitation results in a theoretical subthreshold slope limit of 60 mV/decade at room temperature, which forces the devices to use a high supply voltage leading to high power consumption. This study investigates a new architecture capable of suppressing electron thermal excitation by using a quantum well (QW) as an energy filter. The QW energy filter is composed of a tunneling barrier 1 (0.5 to 1 nm Al2O3 or 0.3-1 nm Si3N4 …

An In Vitro 3d Model To Investigate Iol: Posterior Lens Capsule Interactions On Lens Epithelial Cell Responses, Joyita Roy

Bioengineering Dissertations - Archive

ABSTRACT: Posterior Capsule Opacification (PCO) is the most common complication associated with Intraocular Lens (IOL) implantation. The disease is caused by the infiltration and proliferation of Lens Epithelial Cells (LEC) into the interface between the IOL and Posterior Lens Capsule (PLC). The severity of these cell responses depends on a lot of factors like the IOL design, IOL material, and interaction between the IOL and the posterior lens capsule. While some studies have also shown that adsorption of certain proteins present in the PLC, like fibronectin, may affect IOL-induced PCO in the clinical setting, the mechanism governing such interactions is …

Targeted Drug-Loaded Nanoparticle System (Tdnps) To Ameliorate And Treat Idiopathic Lung Fibrosis, Harish Ramachandramoorthy

Bioengineering Dissertations - Archive

Idiopathic pulmonary fibrosis (IPF) is a fatal progressive disease with a dismal prognosis and 3-5 years of survival. Up to date, there are no effective treatments, and a few current therapies that do not ameliorate the pulmonary fibrosis but rather just increase the survival time by 2-3 years. The major factor limiting the treatment is the lack of targeted therapies to deliver the drugs past the mucosa, into the disease microenvironment. To combat this disease, we proposed a localized therapy via our targeted drug-loaded nanoparticles (TDNPs) to effectively deliver drugs and treat lung fibrosis. Our objective was to design TDNPs …

Performance Evaluation Of The Modified Moisture Barrier In Stabilizing Shallow Slope Failures, Muhasina Manjur Dola

Civil Engineering Dissertations - Archive

Each year significant number of highway slope failures are reported in the United States, especially in states like Texas where expansive clayey soil is prevalent. Slopes constructed over expansive clay often experience recurring shallow failures following their construction which poses maintenance problems to the Texas Department of Transportation (TxDOT). These shallow slope failures can be primarily attributed to the considerable volume change that expansive clay soil undergoes from seasonal climatic variation. Furthermore, under unsaturated conditions during dry periods, high matric suction (i.e., negative porewater pressure) exists in soil slopes. The existence of matric suction contributes to the shear strength of …

Development Of A Decesion Tree To Rehabilitate Or Replace The St. Francis Bridge Over Ih-30, Md Farhan Abir

Civil Engineering Theses - Archive

ABSTRACT: The ASCE infrastructure report card indicated that about 42% of the nation’s bridges are over 50 years old, and 7.5% of the bridges are structurally deficient. The 61-year-old St. Francis bridge over IH-30 is one of the Texas Department of Transportation (TxDOT) bridges that exhibit significant deterioration in the superstructure, including potholes and delamination in the deck. The bridge was load posted to 28,000 lb. limit and has substandard vertical and horizontal clearances to the bottom chord of the beams and supporting piers, respectively, which creates a high risk for vehicle impact. In 2017, an over-height truck struck the …

Study Of The Impact Of Atmospheric Variability On Subsurface Methane Emissions: Application To Leak Detection And Quantification For Underground Natural Gas Pipeline Leaks, Shanru Tian

Civil Engineering Dissertations - Archive

Natural gas (NG), taken as a bridging fuel for achieving a low-carbon future, has rapidly grown to be a significant component of the global energy system and requires extensive pipeline infrastructures, most of them buried underground. Fugitive methane (CH4) emissions from NG pipeline leaks pose environmental, safety, and economic threats to the public. An effective leak detection and quantification (LDAQ) survey method is critical to identifying a leak and assessing the size when it has occurred, thus initiating appropriate response actions to repair it and accounting for the environmental risks accurately. However, gaps exist between LDAQ survey methods, and the …