Mechanical Engineering Commons^™

Nanoscale Imaging Of Antiferromagnetic Domains In Epitaxial Films Of Cr2O3 Via Scanning Diamond Magnetic Probe Microscopy, Adam Erickson, Syed Qamar Abbas Shah, Ather Mahmood, Ilja Fescenko, Christian H. Binek, Adbelghani Laraoui

Department of Mechanical and Materials Engineering: Faculty Publications

We report direct imaging of boundary magnetization associated with antiferromagnetic domains in magnetoelectric epitaxial Cr₂O₃ thin films using diamond nitrogen vacancy microscopy. We found a correlation between magnetic domain size and structural grain size which we associate with the domain formation process. We performed field cooling, i.e., cooling from above to below the Néel temperature in the presence of a magnetic field, which resulted in the selection of one of the two otherwise degenerate 180° domains. Lifting of such a degeneracy is achievable with a magnetic field alone due to the Zeeman energy of a weak …

Biomechanical And Sensory Feedback Regularize The Behavior Of Different Locomotor Central Pattern Generators, Kaiyu Deng, Alexander J. Hunt, Nicholas Szczecinski, Matthew Tresch, Hillel J. Chiel, Charles Heckman, Roger Quinn

Mechanical and Materials Engineering Faculty Publications and Presentations

This work presents an in-depth numerical investigation into a hypothesized two-layer central pattern generator (CPG) that controls mammalian walking and how different parameter choices might affect the stepping of a simulated neuromechanical model. Particular attention is paid to the functional role of features that have not received a great deal of attention in previous work: the weak cross-excitatory connectivity within the rhythm generator and the synapse strength between the two layers. Sensitivity evaluations of deafferented CPG models and the combined neuromechanical model are performed. Locomotion frequency is increased in two different ways for both models to investigate whether the model’s …

Predictions Of Indentation Stiffness Of Musculoskeletal Regions Using Ultrasound, Sean Doherty

ETD Archive

Tissue indentation response is an important metric for understanding how different musculoskeletal regions respond to loading and is a function of the tissue’s form. Modem imaging techniques provide information about the internal structures of human tissue. Ultrasound remains one of the most common imaging techniques performed, given its portability and low costs. Prior work and data collection on 100 patients involved the collection of ultrasound images at eight different locations across the musculoskeletal extremities. Given the tissue structure information that the medical imaging provided, it was hypothesized that the mechanical properties of the tissue could be predicted from this data. …

Strengthening Effects Of Carbon Nanotubes And Graphene Nanoplatelets Reinforced Nickel Metal Matrix Composites, Amit Patil

ETD Archive

Carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) with superior mechanical, thermal, chemical, and electrical properties are appealing reinforcements for the fabrication of lightweight, high-strength, and wear-resistant metal matrix composites with outstanding mechanical and tribological performance. The nickel-carbon nanotube composites (Ni-CNT) and nickel-graphene nano-platelet composites (Ni-GNP) were processed using two separate ball milling methods, namely dry ball milling (DM) and solution ball milling (SBM), and then sintered using the spark plasma sintering (SPS) technique. The influence of the premixing process, milling time, reinforcement morphology, and concentration on matrix grain size, microstructure, dispersion in the nickel matrix, mechanical properties, and tribological performance …

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 …

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 …

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 …

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 …

Koopman Operator Theory And The Applied Perspective Of Modern Data-Driven Systems, Alex Krolicki

All Theses

Recent theoretical developments in dynamical systems and machine learning have allowed researchers to re-evaluate how dynamical systems are modeled and controlled. In this thesis, Koopman operator theory is used to model dynamical systems and obtain optimal control solutions for nonlinear systems using sampled system data. The Koopman operator is obtained using data generated from a real physical system or from an analytical model which describes the physical system under nominal conditions. One of the critical advantages of the Koopman operator is that the response of the nonlinear system can be obtained from an equivalent infinite dimensional linear system. This is …

Architectural Control Of Mesenchymal Stem Cell Phenotype Through Nuclear Actin, Janet Rubin, Andre J. Van Wijnen, Gunes Uzer

Mechanical and Biomedical Engineering Faculty Publications and Presentations

There is growing appreciation that architectural components of the nucleus regulate gene accessibility by altering chromatin organization. While nuclear membrane connector proteins link the mechanosensitive actin cytoskeleton to the nucleoskeleton, actin’s contribution to the inner architecture of the nucleus remains enigmatic. Control of actin transport into the nucleus, plus the presence of proteins that control actin structure (the actin tool-box) within the nucleus, suggests that nuclear actin may support biomechanical regulation of gene expression. Cellular actin structure is mechanoresponsive: actin cables generated through forces experienced at the plasma membrane transmit force into the nucleus. We posit that dynamic actin remodeling …

Design Of A System To Investigate The Relationship Between Feedback And Delivery Medium For A Novel Motor Task, Ashley Humpal

Master's Theses

Stroke is a chronic, lifelong illness, and full recovery requires continuous physical and cognitive rehabilitation. Such long-term rehabilitation is cost-prohibitive; however an approach to providing long-term therapy that has recently gained traction is the use of socially assistive agent (SAA) systems. These systems make use of non-contact communication devices and can be used to guide people through a variety of rehabilitative tasks. They have the potential supplement current rehabilitation practices by providing motivation during intense exercises, and can extend the reach of the therapist into remote and home settings.

Though SAA systems have been used in a variety of rehabilitative …

Multiscale Topology Optimization With A Strong Dependence On Complementary Energy, Dustin Dean Bielecki

All Dissertations

A discrete approach introduces a novel deep learning approach for generating fine resolution structures that preserve all the information from the topology optimization (TO). The proposed approach utilizes neural networks (NNs) that map the desired engineering properties to seed for determining optimized structure. This framework relies on utilizing parameters such as density and nodal deflections to predict optimized topologies. A three-stage NN framework is employed for the discrete approach to reduce computational runtime while maintaining physics constraints.

A continuous representation that uses complementary energy (CE) methods to solve a representative element's homogenized properties consists of an embedded structure that is …

Ultrasound Mediated Tissue Growth In Bioinspired Scaffolds, Marco Fielder

Graduate Theses and Dissertations

Porous scaffolds mechanically stimulated with ultrasound are used for the treatment of bone conditions such as osteoporosis or traumatic bone injury. However, one current issue in these treatment techniques is designing a scaffold structure with a high structural integrity that also does not impede tissue growth. A larger ultrasound wave transmission would also allow more of a scaffold to receive mechanical stimulation from ultrasound. Controlling mesenchymal stem cell seeding of tissue scaffolds also has potential for developing optimal seeding patterns to maximize or control tissue growth in the scaffold based on an individual’s physiology. There is also a need for …

Use Of Precious Plastic Method Of Bricks For The Construction Of Tiny Homes, Haylie E. Tallon

Architectural Engineering

Precious Plastics, a Netherlands based company, created an open source project that can be used to create different objects from recycled plastics. The San Luis Obispo area has a large amount of recyclable plastic that is being treated as trash, adding to the pollution of the ocean and the air. This project is to determine the necessary steps to create plastic building blocks, using the Precious Plastic process, as a construction material for low-income, temporary housing. This report covers the process that was used to build two of the machines that will be used to create the bricks. This requires …

Fabrication And Characterization Of Germanium Functionalized Porous Nickel Oxide Electrodes For Application In Supercapacitors, Cristina Gonzalez

Open Access Theses & Dissertations

Limited fossil fuel, increasing population, pollution, and climate change are motivating society to use renewable and clean energy techniques. However, the intermittent nature of renewable sources hinders their continuous availability and use. Energy storage devices such as supercapacitors and batteries are essential for sustainable development but their high cost limits its bulk use. The cost of energy storage devices mainly depends on materials, synthesis process and device fabrication. Therefore, low cost 3-D mesoporous nickel germanium fictionalize nickel oxides electrode materials has been developed by using facile fabrication techniques for supercapacitor application. 3-D mesoporous nickel provides the high surface area and …

Synthetic Data Generation For Intelligent Inspection Of Structural Environments, Noshin Habib

Open Access Theses & Dissertations

Automated detection of cracks and corrosion in pavements and industrial settings is essential to a cost-effective approach to maintenance. Deep learning has paved the path for vast levels of improvement in the area. Such models require a plethora of data with accurate ground truth and enough variation for the model to generalize to the data, which is notwidely available. There has been recent progress in computer graphics being used for the creation of synthetic data to address the issue of deficient data availability, but it is limited to specific objects, such as cars and human beings. Textures and deformities within …

The Rise Of Terrorism In Africa And What It Means For U.S. Policymakers, Bridget Mary Hughes

Master's Theses

This thesis utilizes three case studies to measure the rise of terrorism in Africa. This qualitative data leads the reader to one ultimate question: what does the rise in terrorism in Africa mean for the United States (U.S.) and U.S. policymakers, National Security academia, students in National Security, if anything at all? The answer is: if civilian and military compounds are being targeted by these violent extremists, as these three case studies demonstrate, it is my recommendation that U.S. policymakers cease sending troops to the African theater and, instead, allocate funding to the citizens and nonprofits of the countries whom …

Multiple Objective Function Optimization And Trade Space Analysis, Yifan Xu

All Theses

Optimization can assist in obtaining the best possible solution to a design problem by varying related variables under given constraints. It can be applied in many practical applications, including engineering, during the design process. The design time can be further reduced by the application of automated optimization methods. Since the required resource and desired benefit can be translated to a function of variables, optimization can be viewed as the process of finding the variable values to reach the function maxima or minima. A Multiple Objective Optimization (MOO) problem is when there is more than one desired function that needs to …

Framework For The Utilization Of The Agile Methodology In Engineering Consulting Services, Cristian Daniel Nuñez

Theses and Dissertations

The guidelines that form the Agile methodology framework are developed and adapted to the engineering consulting services industry. Four tools recommended by the literature are developed and adapted for the specific case of this industry. The implementation of the use of these tools is intended to help adopt the Agile methodology more effectively. A company that performs consulting services for airports is taken as a case study. This company did not officially implement the Agile methodology at the time this research has been done. The data is obtained through a survey designed to associate the company's activities with the guides …

Direct Ink Writing Of Flexible Piezoelectric Sensors, Amanda M. White

Boise State University Theses and Dissertations

Piezoelectric poly(vinylidene fluoride-co-trifluoroethylene), or PVDF-trFE, builds up significant electrical charges on its surface when stressed. By correlating the mechanical force with the resulting electrical charges or voltages, researchers have developed flexible, broadband, and biocompatible force sensors. PVDF-trFE force sensors are traditionally fabricated via spin coating or solvent casting, which result in large waste production and experience difficulties in forming complex geometries. To tackle these challenges, I leveraged a commercial direct ink writing system (nScrypt microdispenser) to additively manufacture PVDF-trFE force sensors. I first synthesized an unprecedented piezoelectric ink that is compatible with a commercial ink writing system at Boise State …

Analysis Of Propeller Designs Focusing On Lowering Sound Pressure Level Through Reduced Tip Loading, Luca A. Zeitvogel

Theses and Dissertations

This research focused on potential design optimizations for small propellers. Designs sought to reduce noise generated without sacrificing efficiency by “unloading” the propeller tip by reducing angle of attack near the tip. To see if nearfield performance improvements translated to a reduction in farfield sound pressure level, farfield experimental acoustic testing was performed on propellers that had been measured experimentally in the nearfield. The farfield results provided limited insight due to an equipment malfunction during testing. However, a large data set was obtained, which provides opportunities for future analyses. A computational simulation sought to recreate some of the nearfield experiments …

Callaway Measurement Device, Andre S. Fisher, Roman Hays, Blake Sousa, Grant Gabrielson

Mechanical Engineering

The purpose of this document is to illustrate the Callaway Measurement Device senior project from start to finish. The challenge given to the team was to update and improve a gauge used by Callaway employees to measure the loft, lie, and face angle of their full spectrum of golf clubs. Once the team understood how the pre-existing gauge operates, the team conducted background research into other technologies that could improve the gauge. The team decided to digitalize the device amongst other tweaks to reduce error. Because the CAD files were not available for the pre-existing device, the team began reverse …

Gasifier Wall Wash Manifold, Ashley Sieu Che, Gintaras Julius Baipsys, Peyton Joseph Archibald, Michael Thomas Kieran

Mechanical Engineering

The objective of our Gasifier Wall Wash Manifold Project is to design three different manifolds that will uniformly distribute water on the inner diameter of a pressure vessel. Also, the distributed water should completely cover the circumference of the inner walls. From extensive research of current solutions as well as the conduction of technical analyses, we were able to produce three designs that would be able to meet our engineering specifications. Time constraints led to the fabrication of one manifold design along with a test rig. With a fully functional test rig, we saw positive results from our design verification …