Mechanics of Materials Commons^™

Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine, Mohamed Sayed Elkady Abd-Elhay

Theses and Dissertations

Wind energy is considered one of the major sources of renewable energy. Nowadays, wind turbine blades could exceed 100 m to maximize the generated power and minimize produced energy cost. Due to the enormous size of the wind turbines, the blades are subjected to failure by aerodynamics loads or instability issues. Also, the gravitational and centrifugal loads affect the wind turbine design because of the huge mass of the blades. Accordingly, wind turbine simulation became efficient in blade design to reduce the cost of its manufacturing. The fluid-structure interaction (FSI) is considered an effective way to study the turbine's behavior …

Minimally Invasive Delivery Of 3d Shape Recoverable Constructs With Ordered Structures For Tissue Repair, Shixuan Chen, Mark Alan Carlson, Xiaowei Li, Aleem Siddique, Wuqiang Zhu, Jingwei Xie

Department of Mechanical and Materials Engineering: Faculty Publications

Minimally invasive procedures are becoming increasingly more common in surgery. However, the biomaterials capable of delivering biomimetic, three-dimensional (3D) functional tissues in a minimally invasive manner and exhibiting ordered structures after delivery are lacking. Herein, we reported the fabrication of gelatin methacryloyl (GelMA)-coated, 3D expanded nanofiber scaffolds and their potential applications in minimally invasive delivery of 3D functional tissue constructs with ordered structures and clinically appropriate sizes (4 cm × 2 cm × 1.5 mm). GelMA-coated, expanded 3D nanofiber scaffolds produced by combining electrospinning, gas-foaming expansion, hydrogel coating, and crosslinking are extremely shape recoverable after release of compressive strain, displaying …

The Effects Of The Transient And Performance Loss Rates On Pv Output Performance, Chibuisi Chinasaokwu Okorieimoh, Brian Norton, Michael Conlon

Conference papers

Solar photovoltaic (PV) panels experience long-term performance degradation as compared to their initial performance, resulting in lower like-per-like efficiencies and performance ratios. Manufacturers of solar photovoltaic modules normally guarantee a lifespan of more than 20 years. To meet such commitments, it is important to monitor and mitigate PV module degradation during this period, as well as beyond, to recognize maintenance and repair needs. Solar PV modules degrade over time, becoming less effective, less reliable, and eventually unusable. The effects of transient and performance loss rates on the output performance of polycrystalline silicon (p-Si) solar PV modules are the focus of …

Maize Tassel Detection From Uav Imagery Using Deep Learning, Aziza Alzadjali, Mohammed H. Alali, Arun Narenthiran Weeranampalayam Sivakumar, Jitender S. Deogun, Stephen Scott, James C. Schnable, Yeyin Shi

Department of Mechanical and Materials Engineering: Faculty Publications

The timing of flowering plays a critical role in determining the productivity of agricultural crops. If the crops flower too early, the crop would mature before the end of the growing season, losing the opportunity to capture and use large amounts of light energy. If the crops flower too late, the crop may be killed by the change of seasons before it is ready to harvest. Maize flowering is one of the most important periods where even small amounts of stress can significantly alter yield. In this work, we developed and compared two methods for automatic tassel detection based on …

Uavs For Vegetation Monitoring: Overview And Recent Scientific Contributions, Ana I. De Castro, Yeyin Shi, Joe Mari Maja, Jose M. Pena

Department of Mechanical and Materials Engineering: Faculty Publications

This paper reviewed a set of twenty-one original and innovative papers included in a special issue on UAVs for vegetation monitoring, which proposed new methods and techniques applied to diverse agricultural and forestry scenarios. Three general categories were considered: (1) sensors and vegetation indices used, (2) technological goals pursued, and (3) agroforestry applications. Some investigations focused on issues related to UAV flight operations, spatial resolution requirements, and computation and data analytics, while others studied the ability of UAVs for characterizing relevant vegetation features (mainly canopy cover and crop height) or for detecting different plant/crop stressors, such as nutrient content/deficiencies, water …

Three-Dimensional Shape Analysis Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer Based On Oct Radial Images, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer angle was recently proposed as a potential index for estimating intracranial pressure noninvasively. However, the ppRPE/BM layer angle, measured from the optical coherence tomography (OCT) scans, varied across the radial directions of the optic disc. This made the ppRPE/BM layer angle difficult to be utilized in its full potential. In this study, we developed a mathematical model to quantify the ppRPE/BM layer angles across radial scans in relation to the ppRPE/BM 3D morphology in terms of its 3D angle and scanning tilt angles. Results showed that the variations of the ppRPE/BM layer …

On The Comparison Of Flow Physics Between Minimal And Extended Flow Units In Turbulent Channels, Ethan A. Davis, Siamak Mirfendereski, Jae Sung Park

Department of Mechanical and Materials Engineering: Faculty Publications

Direct numerical simulations were performed to study the effects of the domain size of a minimal flow unit (MFU) and its inherent periodic boundary conditions on flow physics of a turbulent channel flow in a range of 200 ≤ Re_τ ≤ 1000. This was accomplished by comparing turbulent statistics with those computed in sub-domains (SD) of extended domain simulations. The dimensions of the MFU and SD were matched, and SD dynamics were set to minimize artificial periodicities. Streamwise and spanwise dimensions of healthy MFUs were found to increase linearly with Reynolds number. It was also found that both MFU …

Converting Inorganic Rust To Organic Nanostructured Conducting Polymers: Synthesis And Applications, Yifan Diao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Iron rust is a type of corrosion product, coming from the chemical reaction between iron and oxygen in the presence of water that first documented ca. 800 BCE. It is a heterogeneous inorganic solid-state material composed of multiple phases and is ubiquitous throughout the universe. Rust species such as Hematite (α-Fe2O3), Akaganeite (β-FeOOH), and ferrous hydroxide (Fe(OH)2), make up the solid-state chemical family composed of iron oxides, oxyhydroxides, and hydroxides that are typically recognized as chemical waste. Conducting polymer is a type of organic plastic composed of long chains with repeating subunits that bonding with strong interactions between neighboring molecules. …

Plasmonically-Enhanced Ultrasensitive Biodetection Technologies, Zheyu Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Detection and quantification of biomolecules within biological fluids and tissues is of fundamental importance to biomedical research and clinical diagnostics. It is impossible to fully characterize complex, non-linear, biochemical systems without being able to accurately and quantitatively determine the component molecules. This problem is ubiquitous across all domains of biomedical research, and it is a major barrier to fully understanding health, ageing, and disease. Such bottlenecks are extremely challenging to be solved, especially for proteins and peptides, which do not have amplification schemes such as polymerase chain reaction for nucleic acids, because relevant concentrations of molecules related to diseases such …

Characterization Of Landslide Processes From Radar Remote Sensing And Hydromechanical Modeling, Yuankun Xu

Earth Sciences Theses and Dissertations

Landsides are a natural geomorphic process yet a dangerous hazard which annually causes thousands of casualties and billions of property loss in a global scale. Understanding landslide motion kinematics from early initiation to final deposition is critical for monitoring, assessing, and forecasting landslide movement in order to mitigate their hazards. Landslides occur under diverse environmental settings and appear in variable types; however, all types of landslides can be mechanically attributed to shearing failure at the basal surface due to stress regime shift contributed by internal and/or external forcing. Typical internal factors include soil/rock weathering, whereas typical external triggering forces encompass …

Aerosol Vapor Synthesis Of Organic Processable Pedot Particles And Measuring Electric Conductivity Using A 3d Printed Probe Station, Yang Lu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Conducting polymers are organic semiconductors characterized by conjugated backbones (alternating single-double bonds) that enable mixed ionic-electronic conductivity. Their polymeric nature, tunable band structure and reversible redox capability have demonstrated fundamental advances in the fields ranging from electrochemical energy storage, sensing, to electro/photo catalysis and neuromorphic engineering. Conjugated backbones, the origin of all the unique physical and chemical properties associated with conducting polymers, prevent their solubility due to high lattice energy which hinders processing. Current solution utilizes a long-chain polymer (PSS) as dopants to render conducting polymer water dispersible (PEDOT:PSS). Nonetheless, PSS is highly acidic and hydrophilic limiting applicability with acid-incompatible …

Rational Design And Optimization Of Perovskite Semiconductors, Arashdeep Thind

McKelvey School of Engineering Graduate Student Theses & Dissertations

ABSTRACT OF THE DISSERTATIONRational design and optimization of perovskite semiconductors by Arashdeep Singh Thind Doctor of Philosophy in Materials Science and Engineering Washington University in St. Louis, 2021 Professor Rohan Mishra, Chair

Lead-halide perovskites have emerged as a promising class of semiconductors for next-generation solar cells and optoelectronic devices. Since the report of the photovoltaic effect in 2009 in CH3NH3PbBr3 and CH3NH3PbI3, the power conversion efficiency of these perovskites has rapidly approached 25.2% from 3.8%. These perovskite semiconductors can be synthesized using low-cost solution-based techniques, unlike traditional semiconductors that require slow and expensive growth techniques to reduce the formation of …

Modeling Hydraulic Fracturing Initiation And Propagation In Porous Rock Formationsl, Chang Huang

LSU Doctoral Dissertations

Hydraulic fracturing has long been introduced to the oil and gas industry since the early nineteenth century for both reservoir characterization and reservoir stimulation. Despite the progress made in the last two decades, many challenges still have not been tackled regarding not only the propagation problem but also the initiation problem due to its complexity. The dissertation is divided into two stages, i.e., before and after fracture initiation. The first stage of the research aimed at improving the accuracy in solving the poro-mechanical response of wellbore during fluid injection before a tensile fracture occurs, which is crucial to determine the …

Higher-Order Topolectrical Semimetal Realized Via Synthetic Gauge Fields, Xiang Ni, Andrea Alù

Advanced Science Research Center

Classical bosonic systems may be tailored to support topological order and unidirectional edge transport exploiting gauge fields. Here, we theoretically explore how synthetic gauge fields may be used to induce higher-order topological phases and zero-energy boundary states. We demonstrate these principles in two types of three-dimensional topolectrical circuits with synthetic gauge fields threading through their reduced two-dimensional lattices, leading to a half-quantized quadrupole charge within a region of the momentum space. We theoretically show the emergence of nodal line rings and Weyl points in the bulk dispersion, whose projected surfaces and hinges support surface Fermi arcs and flat hinge Fermi …

High Frequency Electron Spin Resonance Investigations On Quasi-Two-Dimensional Chromium Halide Magnets, Christian Saiz

Open Access Theses & Dissertations

Broadening the knowledge and understanding on the magnetic correlations in van der Waals layered magnets is critical in realizing their potential next-generation applications in devices such as spintronics. In this study, we employ high frequency (ν = 120 GHz, 240 GHz) electron spin resonance (ESR) spectroscopy on plate-like CrX3 (where X = Cl, Br, I) to gain insight into the magnetic interactions as a function of temperature (200 – 4.4 K) and the angle of rotation θ (degrees). We find that the temperature dependence of the ESR linewidth is well described by the Ginzburg-Landau critical model, indicative of antiferromagnetic correlations …

Synthesis And Characterization Of Functiona Materials For 3d Printed Composites, Elizabeth Irene Reza

Open Access Theses & Dissertations

The following body of work encompasses the synThesis, upscaling, additive manufacturing, and characterization of microspheres as functional fillers incorporated into polymer syntactic foams. Synthesizing microspheres permits control over morphology, dispersion of particles, and size while the use of direct write manufacturing allowed for the controllability of filler orientation. Two different syntactic foams were developed from similar methodologies: (1) a silicone syntactic foam (2) epoxy syntactic foam. The silicone epoxy foam showed an increasing in damping and elastic modulus. The epoxy syntactic foams showed an enhanced thermal and electrical properties.

Mechanical Behavior Of Cyclo-18 On Nickel And Copper Substrates, Reagan Michael Kraft

Mechanical Engineering Undergraduate Honors Theses

Carbyne, an -hybridized allotrope of carbon, has been the subject of many studies recently due to its incredible mechanical properties and small size. More recently, another -hybridized allotrope known as cyclo-18, has gained interest. In this study, computational molecular dynamics will be used to determine the mechanical properties of cyclo-18. Peeling and shearing tests of the molecule will be conducted on nickel and copper, which are respectively active and less-active transition metals. Additionally, a carbyne chain of equal length will undergo the same tests on the copper substrate to compare the mechanical properties of the two. The results conclude that …

A Study Of The Frustrated Honeycomb Battery Material Na2ni2teo6, Nathan Christopher Episcopo

Open Access Theses & Dissertations

The P2-type layered hexagonal compound Na2Ni2TeO6 with Ni2+ on a honeycomb lattice was synthesized by the standard solid-state route. Structural characterization chemical phase purity was confirmed by Rietveld refinement of laboratory and synchrotron data. The crystal structure refines well in the P63/mcm space group. Single crystal growth trials using the self-flux-melt method were conducted with limited success. The magnetic transition temperature pertaining to Ni2+ lattice was confirmed by analysis of specific heat capacity to be . The magnetic susceptibility remains largely unchanged in magnetic field of and external pressure of . There is an almost linear response in isothermal magnetization …

New Generation Of Performance-Engineered Asphalt Mixtures Based On Balanced Mix Design Concept, Victor Manuel Garcia

Open Access Theses & Dissertations

Asphalt mixtures must ideally exhibit long-lasting durability and stability to perform wellin the field. However, improving the stability and durability of asphalt mixtures has become a major concern. Given that available design approaches rely mainly on stringent volumetric criteria for asphalt mixtures, design approaches and specifications that incorporate performance tests are needed to follow a performance-engineered mix design (PEMD) process, especially with the introduction of the balanced mix design (BMD) concept

This Dissertation study presents a comprehensive investigation of a feasible designapproach that can be implemented to develop PEMD specifications and produce BMD mixtures. An experimental evaluation of different mix …

Development And Testing Of Nanostructured Materials For Extreme Environment Applications, Nanthakishore Makeswaran

Open Access Theses & Dissertations

Nanostructured materials have many potential applications in the fields of power generation and transportation technologies, particularly in the areas of gas sensing technology, industrial gas turbines and protective coatings. In the former case β-Ga2O3 represents a promising candidate due to its high degree of stability and functionality for oxygen sensing at higher temperatures (>700oC). In the latter case, the application of Y-Si-Fe compounds acting as environmental barrier coatings for gas turbine and aerospace engine applications to protect from corrosion effects has been demonstrated in recent years. In both cases, however, there is room for improvement whether it is in …

Post Processing Of Electron Beam Melted Ti-6al-4v And Binder Jetted 17-4 Stainless Steel, Ahmad Omar Abu-Issa

Open Access Theses & Dissertations

An extensive assortment of HIP parameters have been altered on EBM fabricated Ti-6Al-4V and have shown that cooling rates of 103 oC/min from temperatures above and below the beta transus produced acicular alpha-prime martensite characteristic elongations < 10 %. Optimum yield strength (0.9 GPa), UTS (1.0 GPa) and elongation (~14 %) were achieved for slow cooling (at 102 oC/min) from 850 oC HIP which produced a dense, Widmanstatten alpha structure within the retained, as-fabricated columnar grains by alpha-prime decomposition. These results suggest that manipulation of AM process parameters to produce a small-grain, equiaxed microstructure, HIPed below the beta transus and slow cooled, will have a wide range of superior, isotropic mechanical properties corresponding to a Widmanstatten alpha microstructure within the equiaxed grains. Also, Binder Jetting printing parameters for differing PSD's of low-cost water-atomized 17-4 Stainless Steel were optimized in order to produce high dense parts. Densities ranging from 94-97.5% were achieved, and issues of inhomogeneous porosity were addressed using a fumed silica flow additive.

Mixed Mode Crack Propagation In Iliac Bone, E. Baesu, Dm. Iliescu, Bv. Radoiu, S. Halichidis

Department of Mechanical and Materials Engineering: Faculty Publications

Bone is a complex material that can be regarded as an anisotropic elastic composite material. The problem of crack propagation in hu- man bone is analyzed by using a generalization of the maximum tensile stress criterion (MTS). The results concern the critical stress for crack propagation and the direction of the crack path in Iliac bone.

Special Issue “Cfd Modeling Of Complex Chemical Processes: Multiscale And Multiphysics Challenges”, Li Xi, De-Wei Yin, Jae Sung Park

Department of Mechanical and Materials Engineering: Faculty Publications

No abstract provided.

Improving Accuracy Of Unmanned Aerial System Thermal Infrared Remote Sensing For Use In Energy Balance Models In Agriculture Applications, Mitchell S. Maguire, C.M.U. Neale, Wayne E. Woldt

Department of Mechanical and Materials Engineering: Faculty Publications

Unmanned aerial system (UAS) remote sensing has rapidly expanded in recent years, leading to the development of several multispectral and thermal infrared sensors suitable for UAS integration. Remotely sensed thermal infrared imagery has been used to detect crop water stress and manage irrigation by leveraging the increased thermal signatures of water stressed plants. Thermal infrared cameras suitable for UAS remote sensing are often uncooled microbolometers. This type of thermal camera is subject to inaccuracies not typically present in cooled thermal cameras. In addition, atmospheric interference also may present inaccuracies in measuring surface temperature. In this study, a UAS with integrated …

Durability Of Concrete Using Foundry Waste Sand, Meshari Alrajab

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Business and Technology Morehead State University in partial fulfillment of the requirements for the Degree Master of Science by Meshari Alrajab on April 20, 2021.

Quantifying Surface Morphology Of Manufactured Activated Carbon And The Waste Coffee Grounds Using The Getis-Ord-Gi* Statistic And Ripley’S K Function, Sanghoon Lee, Sukjoon Na, Olivia G. Rogers, Sungmin Youn

All Engineering Faculty Research

Activated carbon can be manufactured from waste coffee grounds via physical and/or chemical activation processes. However, challenges remain to quantify the differences in surface morphology between manufactured activated carbon granules and the waste coffee grounds. This paper presents a novel quantitative method to determine the quality of the physical and chemical activation processes performed in the presence of intensity inhomogeneity and identify surface characteristics of manufactured activated carbon granules and the waste coffee grounds. The spatial density was calculated by the Getis-Ord-Gi* statistic in scanning electron microscopy images. The spatial characteristics were determined by analyzing Ripley’s K function and complete …

Six-Sigma Quality Management Of Additive Manufacturing, Hui Yang, Prahalad Rao, Timothy Simpson, Yan Lu, Paul Witherell, Abdalla R. Nassar, Edward Reutzel, Soundar Kumara

Department of Mechanical and Materials Engineering: Faculty Publications

Quality is a key determinant in deploying new processes, products, or services and influences the adoption of emerging manufacturing technologies. The advent of additive manufacturing (AM) as a manufacturing process has the potential to revolutionize a host of enterprise-related functions from production to the supply chain. The unprecedented level of design flexibility and expanded functionality offered by AM, coupled with greatly reduced lead times, can potentially pave the way for mass customization. However, widespread application of AM is currently hampered by technical challenges in process repeatability and quality management. The breakthrough effect of six sigma (6S) has been demonstrated in …

Anisotropic Scaffolds For Peripheral Nerve And Spinal Cord Regeneration, Wen Xue, Wen Shi, Yunfan Kong, Mitchell Kuss, Bin Duan

Department of Mechanical and Materials Engineering: Faculty Publications

The treatment of long-gap (>10 mm) peripheral nerve injury (PNI) and spinal cord injury (SCI) remains a continuous challenge due to limited native tissue regeneration capabilities. The current clinical strategy of using autografts for PNI suffers from a source shortage, while the pharmacological treatment for SCI presents dissatisfactory results. Tissue engineering, as an alternative, is a promising approach for regenerating peripheral nerves and spinal cords. Through providing a beneficial environment, a scaffold is the primary element in tissue engineering. In particular, scaffolds with anisotropic structures resembling the native extracellular matrix (ECM) can effectively guide neural outgrowth and reconnection. In …

Influence Of Parameters Of Non-Standard Modes Of Heat Treatment On Increasing The Wear Resistance Of Steel Products, Dorob Murotovich Berdiyev Dsn, Abdulaziz Abdullajanovich Yusupov Head Teacher, Ravshan Kobilovich Tashmatov Doctoral Student, Tuychi Nemat Ogli Ibodullayev Assistant, Kabira Erkinovna Qurbonova Head Teacher

Scientific-technical journal

The use of non-standard modes of heat treatment increases the density of dislocations in the crystal structure of the α-phase and increases the wear resistance of carbon, low-alloy steels under various friction conditions, which is comparable to the results when heated to a standard temperature (Ac₃+30÷50 °C). The preliminary extreme heating temperature is determined. After re-quenching at standard temperature and low tempering, the wear resistance of steels under various types of friction increases by up to 40 % compared to standard quenching.

Influence Of Parameters Of Non-Standard Modes Of Heat Treatment On Increasing The Wear Resistance Of Steel Products, Dorob Murotovich Berdiyev Dsn, Abdulaziz Abdullajanovich Yusupov Head Teacher, Ravshan Kobilovich Tashmatov Doctoral Student, Tuychi Nemat Ogli Ibodullayev Assistant, Kabira Erkinovna Qurbonova Head Teacher

Scientific-technical journal

The use of non-standard modes of heat treatment increases the density of dislocations in the crystal structure of the α-phase and increases the wear resistance of carbon, low-alloy steels under various friction conditions, which is comparable to the results when heated to a standard temperature (Ac₃+30÷50 °C). The preliminary extreme heating temperature is determined. After re-quenching at standard temperature and low tempering, the wear resistance of steels under various types of friction increases by up to 40 % compared to standard quenching.