Materials Science and Engineering Commons^™

A Pyrrole Modified 3,4-Propylenedioxythiophene Conjugated Polymer As Hole Transport Layer For Efficient And Stable Perovskite Solar Cells, Yuanhao Tang, Ke Ma, Wenhao Shao, Yoon Ho Lee, Ashkan Abtahi, Jiaonan Sun, Hanjun Yang, Aidan H. Coffey, Harindi R. Atapattu, Mustafa Ahmed, Qixuan Hu, Wenzhan Xu, Raunak Dani, Limei Wang, Chenhui Zhu, Kenneth R. Graham, Jianguo Mei, Letian Dou

Chemical and Materials Engineering Faculty Publications

Despite the outstanding electric properties and cost-effectiveness of poly- (3,4-ethylenedioxythiophene) (PEDOT) and its derivatives, their performance as hole transport layer (HTL) materials in conventional perovskite solar cells (PSCs) has lagged behind that of widely used spirobifluorene-based molecules or poly(triaryl amine). This gap is mainly from their poor solubility and energy alignment mismatch. In this work, the design and synthesis of a pyrrole-modified HTL (PPr) based on 3,4-propylenedioxythiophene (ProDOT) are presented for efficient and stable PSCs. As a result of the superior defects passivation ability, excellent contact with perovskite, enhanced hole extraction, and high hydrophobicity, the unencapsulated PPr-based PSCs showed the …

Analysis Of Tar And Oil Derived From Pyrolysis And Copyrolysis Of Waste Plastics And Biomass, Anitha Shankaralinge Gowda, Dimitrios Karadimas, Jeffrey Seay

Chemical and Materials Engineering Faculty Publications

Pyrolysis has been proposed as a potential technology for managing the growing volume of plastic waste generated worldwide. Co-pyrolysis of plastic waste with biomass is a promising technology for generating fuel and chemical products. However, this process generates tar as a waste product. The chemical properties of this tar have yet to be thoroughly analyzed. This study presents the results of gas chromatography–mass spectrometry (GC–MS), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) of oil and tar obtained from the pyrolysis of pure plastics including high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyethylene (PE), polystyrene (PS), and plastic-biomass mixtures. GC–MS analysis …

Membrane Filtration Of Nanoscale Biomaterials: Model System And Membrane Performance Evaluation For Aav2 Viral Vector Clarification And Recovery, Mara Leach, Kearstin Edmonds, Emily Ingram, Rebecca E. Dutch, Ranil Wickramasinghe, Malgorzata Chwatko, Dibakar Bhattacharyya

Chemical and Materials Engineering Faculty Publications

The growing demand for viral vectors as nanoscale therapeutic agents in gene therapy necessitates efficient and scalable purification methods. This study examined the role of nanoscale biomaterials in optimizing viral vector clarification through a model system mimicking real AAV2 crude harvest material. Using lysed HEK293 cells and silica nanoparticles (20 nm) as surrogates for AAV2 crude harvest, we evaluated primary (depth filters) and secondary (membrane-based) filtration processes under different process parameters and solution conditions. These filtration systems were then assessed for their ability to recover nanoscale viral vectors while reducing DNA (without the need for endonuclease treatment), protein, and turbidity. …

Fundamental And Application Of Co-Assembly Of Peptides And Proteins: Experiment And Computation, Newton A. Ihoeghian, Qing Shao

Chemical and Materials Engineering Faculty Publications

Peptides and proteins can co-assemble into various nanostructures based on complementary non-covalent interactions such as electrostatic forces, hydrogen bonding, and hydrophobic associations. These co-assemblies create a design space of functional materials for a wide spectrum of energy, environmental, and biomedical applications. This review focuses on the fundamentals and applications of three co-assembling systems: ultra-short peptides, peptides, and proteins. We will present and discuss experimental studies demonstrating applications in drug delivery, tissue engineering, and biomaterials development. We will also discuss the contribution of computational research, including molecular dynamics simulations and machine learning, to enhance our understanding of assembly mechanisms. Integrating experimental …

Supercapacitors With Cotton Shell-Derived Activated Carbons And Porous Polymer Electrolyte Films, Saurabh Singh, Yulin Zhang, S. A. Hashmi, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Some of the well-known challenges in the field of supercapacitors (SCs), or more specifically, electrical double-layer capacitors (EDLCs), such as low energy density and high cost, have proven to be major barriers to their widespread market success despite having some excellent electrochemical merits such as high-power density and good cyclic stability. In this work, efforts have been made to overcome these gaps and eventually enhance the performance of EDLCs via a cost-effective and eco-friendly approach. To fabricate these EDLCs, a bio-waste, namely, cotton-shell-derived activated carbons (ZnACs) (activated with ZnCl2), was used in a mass ratio of 1 : 2 for …

Improvement Of Cellular Pattern Organization And Clarity Through Centrifugal Force, Lauren E. Mehanna, James D. Boyd, Shelley Remus-Williams, Nicole M. Racca, Dawson P. Spraggins, Martha E. Grady, Brad J. Berron

Chemical and Materials Engineering Faculty Publications

Rapid and strategic cell placement is necessary for high throughput tissue fabrication. Current adhesive cell patterning systems rely on fluidic shear flow to remove cells outside of the patterned regions, but limitations in washing complexity and uniformity prevent adhesive patterns from being widely applied. Centrifugation is commonly used to study the adhesive strength of cells to various substrates; however, the approach has not been applied to selective cell adhesion systems to create highly organized cell patterns. This study shows centrifugation as a promising method to wash cellular patterns after selective binding of cells to the surface has taken place. After …

Integrating Protein Language Model And Molecular Dynamics Simulations To Discover Antibiofouling Peptides, Ibrahim A. Imam, Shea Bailey, Duolin Wang, Shuai Zeng, Dong Xu, Qing Shao

Chemical and Materials Engineering Faculty Publications

Antibiofouling peptide materials prevent the nonspecific adsorption of proteins on devices, enabling them to perform their designed functions as desired in complex biological environments. Due to their importance, research on antibiofouling peptide materials has been one of the central subjects of interfacial engineering. However, only a few antibiofouling peptide sequences have been developed. This narrow scope of antibiofouling peptide materials limits their capacity to adapt to the broad spectrum of application scenarios. To address this issue, we searched for antibiofouling peptides in the vast sequence pool of the microbiome library using a combination of deep learning-based high-throughput search and molecular …

Clarifying The Role Of Η-Phase With Varying Chemistry On Localised Corrosion Of A Cu-Containing 7xxx Al-Alloy By Quasi-In-Situ Tem, S. K. Kairy, Y. Wu, S. Turk, A. Shekhter, Rudolph Buchheit, N. Birbilis

Chemical and Materials Engineering Faculty Publications

Quasi-in-situ transmission electron microscopy was employed to study dissolution associated with η-phase (Mg(Zn,Al,Cu)₂) precipitates in a Cu-containing 7xxx Al-alloy. Two distinct η-phase chemistries, with Cu to (Zn+Mg+Al) ratios ∼0.12 and ∼0.2, were studied in 0.01 M NaCl at pH 6 and 2. In near-neutral NaCl, both η-phase precipitates exhibited ‘duplex’ behaviour, i.e., they were primarily more noble with respect to the surrounding Al-matrix, causing matrix dissolution, and simultaneously established nanoscopic active sites within the noble precipitate itself by generating nanoscale pits. Conversely, η-phase precipitates rapidly dealloyed in acidic NaCl, forming nocrystalline Cu remnants containing twins, which subsequently caused …

Enhancing Intrinsic Ductility In Vnbmotaw High Entropy Alloy: A Combinatorial Investigation With Experimental Evaluation Of Theoretical Predictions, Taohid Bin Nur Tuhser, Ian Stewart Winter, Daryl Chrzan, Thomas John Balk

Chemical and Materials Engineering Faculty Publications

The application of refractory high entropy alloys (RHEAs) as engineering materials has been hindered by their poor inherent ductility. In this study, a novel approach combining thin film combinatorial screening with fragmentation testing was employed to identify intrinsically ductile alloy compositions. Inspired by the physics-based intrinsic ductility parameter, the ‘χ-parameter,’ we investigated the replacement of group VI elements (W/Mo) with group V elements (V, Nb, Ta) in the VNbMoTaW system. Conventional combinatorial analyses, including composition, phase, and hardness assessments, were conducted across a wide range of non-equiatomic configurations. The results revealed a broad compositional space favoring a single-phase body-centered cubic …

Advances In Magnetic Nanoparticles For Molecular Medicine, Xiaoyue Yang, Sarah E. Kubican, Zhongchao Yi, Sheng Tong

Markey Cancer Center Faculty Publications

Magnetic nanoparticles (MNPs) are highly versatile nanomaterials in nanomedicine, owing to their diverse magnetic properties, which can be tailored through variations in size, shape, composition, and exposure to inductive magnetic fields. Over four decades of research have led to the clinical approval or ongoing trials of several MNP formulations, fueling continued innovation. Beyond traditional applications in drug delivery, imaging, and cancer hyperthermia, MNPs have increasingly advanced into molecular medicine. Under external magnetic fields, MNPs can generate mechano- or thermal stimuli to modulate individual molecules or cells deep within tissue, offering precise, remote control of biological processes at cellular and molecular …

Surface Morphology And Moisture Adsorption/Desorption Characteristics Of Hybrid-Dielectric Moisture Sensors, Ronak Ali

Theses and Dissertations--Electrical and Computer Engineering

Relative humidity sensors are used for high-humidity measurement. Moisture sensors, or dew point sensors are used for low-humidity measurement (< 1 ppm_v). The dissertation contains two parts of studies. In the first part, the effect of surface morphology on the response speed of moisture sensors is studied. Moisture sensors using α-Al₂O₃ films as porous dielectric materials deposited by anodic spark deposition are studied. In this part of the study, a variety of small pores have been studied to investigate the response speed of moisture sensors. Three different surface morphologies have been studied using scanning electron microscopy. One …

Characterization Of The Solid-State Bonding For Simulated Charge And Seam Welds In The Porthole Die Extrusion Process, Randall L. Bowers

Theses and Dissertations--Chemical and Materials Engineering

The isothermal (ISO-T) compression configuration is ideal for utilizing as a material input of flow stress at temperature and strain rate in models of the porthole die extrusion process due to the isothermal nature of the test. Micro-tensile testing was conducted to validate the solid-state welding integrity of the ISO-T samples at various temperatures and strain rates. Results of the mechanical testing were correlated with fractography and microstructural evaluations of the welds to confirm bonding behavior. Both clean interface conditions and oxidation and lubrication layers were evaluated to simulate the difference of seam and charge welds in the process. Results …

Combinatorial Thin Film Approach To Accelerate Materials Discovery: Development Of Nanoporous And Bulk Multi-Principal Element Alloys, Tibra Das Gupta

Theses and Dissertations--Chemical and Materials Engineering

Multi-principal element alloys (MPEAs) have garnered significant attention in materials science due to their potential for exhibiting a combination of desirable properties stemming from their unique configurational entropy. While early research focused on equiatomic compositions, recent studies have indicated that non-equiatomic MPEAs may offer superior mechanical performance. However, the identification of optimal non-equiatomic compositions remains challenging due to the vast compositional space and the reliance on time-consuming and computationally expensive methods. This dissertation presents a combinatorial thin film approach as a rapid and efficient strategy for discovering two types of materials: nanoporous and bulk MPEAs.

The first study explores the …

Microstructural Characterization Of Complex Metal Alloy Systems With A Focus On Electron Microscopy, Alexandra Allamon

Theses and Dissertations--Chemical and Materials Engineering

Multi-principal element alloys (MPEAs)/high-entropy alloys (HEAs) are a class of materials that provide novel and superior combinations of properties, with promise for use in challenging application areas that many of the current established materials cannot fit. With a higher number of constituent elements, many of the newly created alloys are compositionally complex in nature, known to contain combinations of relatively soft FCC phases, hard BCC phases, and, in some cases, even harder intermetallic phases. Microstructural study of these new materials is essential to understanding the enhanced properties they may possess, but their complexity can make this study much more challenging …

Ion Hydration In Bulk And Nanoconfined Water: Insights From Machine Learning Force Fields, Zachary D. Baker

Theses and Dissertations--Chemical and Materials Engineering

Understanding ionic hydration remains a central challenge in physical chemistry and materials science, as the interactions between ions and water molecules govern diverse phenomena ranging from electrolyte transport to selective ion separation. While experimental techniques have provided invaluable insights into solvation energetics and coordination numbers, they often lack atomistic resolution, particularly under nanoscale confinement where direct measurement becomes infeasible. Molecular dynamics (MD) simulations can bridge this gap; however, conventional classical force fields are limited by their simplified, fixed functional forms and empirical parameterization, whereas ab initio molecular dynamics (AIMD) achieves higher accuracy at the expense of severe computational cost and …

Understanding The Influence Of Applied Magnetic Field On Aluminum Alloys: Implications On Strength, Precipitate Development And Diffusion Of Solutes, Damilola David Alewi

Theses and Dissertations--Chemical and Materials Engineering

The processing of certain metals and alloys under magnetic fields presents a promising yet underexplored frontier for controlling microstructure alongside improving physical and mechanical properties. Magnetic fields can be strategically applied at different stages of materials processing, from melting and solidification to subsequent heat treatments to achieve targeted properties in materials. Although magnetic fields have been found to aid changes in microstructural evolution and phase equilibria in ferrous materials, there is limited application of this technique in non-ferrous material systems. This dissertation aims at contributing to the understanding of the influence of magnetic field on the mechanical properties and solid-state …

The Effect Of Organic Semiconductor Electron Affinity On Preventing Parasitic Oxidation Reactions Limiting Performance Of N-Type Organic Electrochemical Transistors, Maryam Alsufyani, Benjamin Moss, Claudia E. Tait, William K. Myers, Maryam Shahi, Katherine Stewart, Xiaolei Zhao, Reem B. Rashid, Dilara Meli, Ruiheng Wu, Bryan D. Paulsen, Karl J. Thorley, Yuanbao Lin, Craig Combe, Charlie Kniebe-Evans, Sahika Inal, Sang Young Jeong, Han Young Woo, Grant Ritchie, Ji-Seon Kim, Jonathan Rivnay, Alexandra F. Paterson, James R. Durrant, Iain Mcculloch

Chemical and Materials Engineering Faculty Publications

A key challenge in the development of organic mixed ionic-electronic conducting materials (OMIEC) for high performance electrochemical transistors is their stable performance in ambient. When operating in aqueous electrolyte, potential reactions of the electrochemically injected electrons with air and water could hinder their persistence, leading to a reduction in charge transport. Here, the impact of deepening the LUMO energy level of a series of electron-transporting semiconducting polymers is evaluated, and subsequently rendering the most common oxidation processes of electron polarons thermodynamically unfavorable, on organic electrochemical transistors (OECTs) performance. Employing time resolved spectroelectrochemistry with three analogous polymers having varying electron affinities …

Investigating The Effect Of Microwave Pretreatment On Bastnasite Grinding For Comminution Energy Reduction And Rare Earth Recovery, Kaveh Asgari, Qingqing Huang, Rick Q. Honaker, Edward Sabolsky

Chemical and Materials Engineering Faculty Publications

This study explored the impact of microwave pretreatment on the grinding efficiency of bastnaesite ore using a stirred mill. Bastnaesite ore was prepared using a staged crushing and sieving process, followed by microwave pretreatment in a specially designed microwave furnace system. Representative samples of the crushed ore underwent stirred mill grinding, with power draw measurements recorded and adjusted to reflect only the specific energy input required for grinding. Particle size distribution was analyzed periodically using laser particle size analysis. In addition, a Box–Behnken design was used to statistically assess the effects of various parameters on the results, ensuring a robust …

Size And Shape Dependence Of Hydrogen-Induced Phase Transformation And Sorption Hysteresis In Palladium Nanoparticles, Xingsheng Sun, Rong Jin

Chemical and Materials Engineering Faculty Publications

Phase transitions of metals in hydrogen (H) environments are critically import- ant for applications in energy storage, catalysis, and sensing. Nanostructured metallic particles can lead to faster charging and discharging kinetics, increased lifespan, and enhanced catalytic activities. However, establishing a direct causal link between nanoparticle structure and function remains challenging. In this work, we establish a computational framework to explore the atomic config- uration of a metal-hydrogen system when in equilibrium with a H environ- ment. This approach combines Diffusive Molecular Dynamics with an itera- tion strategy, aiming to minimize the system’s free energy and ensure uniform chemical potential across …

Engineering The Coherent Phonon Transport In Polar Ferromagnetic Oxide Superlattices, In Hyeok Choi, Seung Gyo Jeong, Do-Gyeom Jeong, Ambrose Seo, Woo Seok Choi, Jong Seok Lee

Chemical and Materials Engineering Faculty Publications

Artificial superlattices composed of perovskite oxides serves as an essential platform for engineering coherent phonon transport by redefining the lattice periodicity, which strongly influences the lattice-coupled phase transitions in charge and spin degrees of freedom. However, previous methods of manipulating phonons have been limited to controlling the periodicity of superlattice, rather than utilizing complex mutual interactions that are prominent in transition metal oxides. In this study on oxide superlattices composed of ferromagnetic metallic SrRuO3 and quantum paraelectric SrTiO3 , phonon modulation by controlling the geometry of superlattice in atomic-scale precision is realized, demonstrating the coherent phonon engineering using structural and …

The Undergraduate Engineering Mental Health Help-Seeking Instrument (Ue-Mh-Hsi): Development And Validity Evidence, Joseph H. Hammer, Courtney J. Wright, Melanie E. Miller, Sarah A. Wilson

Chemical and Materials Engineering Faculty Publications

Background: Undergraduate engineering students experiencing distress are less likely than peers to ask for professional help. A population-specific instrument to facilitate the identification of factors that influence mental healthcare utilization could guide development and testing of interventions to increase help seeking.

Purpose: We used mixed methods guided by the Integrated Behavioral Model (IBM) to develop and evaluate the Undergraduate Engineering Mental Health Help-Seeking Instrument (UE-MH-HSI).

Method: First, we adapted existing measures of mental health help-seeking intention and mechanisms (i.e., attitudes, perceived norm: injunctive, perceived norm: descriptive, personal agency: autonomy, personal agency: capacity). Second, we coded qualitative interviews (N = 33) …

Analysis Of The Thermal Aging Kinetics Of Tallow, Chicken Oil, Lard, And Sheep Oil, Yun-Chuan Hsieh, Hao Ouyang, Yulin Zhang, Donyau Chiang, Fuqian Yang, Hsin-Lung Chen, Sanboh Lee

Chemical and Materials Engineering Faculty Publications

Understanding the thermal aging kinetics of animal oils is of vital importance in the storage and applications of animal oils. In this work, we use four different techniques, including UV-Vis spectrometry, viscometry, impedance spectroscopy, and acid–base titration, to study the thermal aging kinetics of tallow, chicken oil, lard, and sheep oil in the temperature range from 120 ◦C to 180 ◦C. The evolutions of the UV-Vis absorbance, dynamic viscosity, electric impedance, and acid titration are discussed with the defect kinetics. The evolutions of the color centers, defects for dynamic viscosity, and electric dipoles follow second-order, first-order, and zero-order kinetics, respectively. …

Growth And Faceting Of Tungsten And Oxides In Scandate Cathode Particles During In Situ Heating In The Scanning Electron Microscope, Huanhuan Bai, Thomas John Balk

Chemical and Materials Engineering Faculty Publications

Tungsten-based scandate dispenser cathodes are promising next-generation thermionic electron sources for vacuum electron devices, due to their excellent emission performance at tempera- tures lower than those required for conventional cathodes. There has been a significant recent effort to understand scandate cathode performance and to characterize the tungsten and other materials on the emitting surface, primarily via the study of cathodes before and after emission testing. Moreover, these scandate cathodes have typically been characterized at room temperature only. In situ obser- vations of scandate cathodes is challenging, as these devices are thermionic emitters that operate in a high-vacuum environment, and because …

Effects Of External Pressure On Cycling Performance Of Silicon-Based Lithium-Ion Battery: Modelling And Experimental Validation, Kai Zhang, Yinan He, Junwu Zhou, Xinyang Wang, Yong Li, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Controlling the stress state of electrodes during electrochemical cycling can have a positive effect on the cycling performance of lithium-ion battery. In this work, we study the cycling performance of silicon-based lithium-ion half cells under the action of pressure in a range of 0.1 to 0.4 MPa. The cycling performance of the silicon-based lithium-ion half cells increases first with increasing the pressure to 0.2 MPa and then decreases with further increasing the pressure. The analysis of the surface morphologies of cycled electrodes reveals that applying a pressure of 0.2 MPa leads to the formation of fine electrode surface with the …

Enhancing Thermal Stability Of Perovskite Solar Cells Through Thermal Transition And Thin Film Crystallization Engineering Of Polymeric Hole Transport Layers, Sanggyun Kim, Sina Sabury, Carlo A. R. Perini, Tareq Hossain, Augustine O. Yusuf, Xiangyu Xiao, Ruipeng Li, Kenneth R. Graham, John R. Reynolds, Juan-Pablo Correa-Baena

Chemical and Materials Engineering Faculty Publications

Organic hole transport layers (HTLs) have been known to be susceptible to thermal stress, leading to poor long- term stability in perovskite solar cells (PSCs). We synthesized three 2,5-dialkoxy-substituted, 1,4-bis(2-thienyl)phenylene (TPT)-based conjugated polymers (CPs) linked with thiophene-based (thiophene (T) and thienothiophene (TT)) comonomers and evaluated them as HTLs in n-i-p PSCs. TPT-T (MB/C6), which has branched 2- methylbutyl and linear hexyl (MB/C6) side chains, emerged as a promising HTL candidate, enabling power conversion efficiencies (PCEs) greater than 15%. In addition, PSCs with this HTL showed an improvement in long-term stability at elevated temperatures of 65 °C when compared to those …

Resolving The Size And Charge Of Small Particles: A Predictive Model Of Nanopore Mechanics, Samuel Bearden, Tigran M. Abramyan, Dmitry Gil, Jessica Johnson, Anton Murashko, Sergei Makaev, David Mai, Alexander Baranchikov, Vladimir Ivanov, Vladimir Reukov, Guigen Zhang

Chemical and Materials Engineering Faculty Publications

The movement of small particles and molecules through nanopore membranes is widespread and has far-reaching implications. Consequently, the development of mathematical models is essential for understanding these processes on a micro level, leading to deeper insights. In this endeavor, we suggested a model based on a set of empirical equations to predict the transport of substances through a solid-state nanopore and the associated signals generated during their translocation. This model establishes analytical relationships between the ionic current and electrical double-layer potential observed during analyte translocation and their size, charge, and mobility in an electrolyte solution. This framework allows for rapid …

Pulsing-Induced Healing Of A Surface Crack Of A Nickel-Based Alloy, Liwei Wang, Mingming Quan, Zhen Tan, Ming Liu, Dianlong Wang, Xiao Yang, Ying Liu, Yaning Mao, Zhimin Liang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this work, we demonstrate the feasibility of applying electric pulses to heal surface cracks on nickel-based alloy GH4169 under compressive load. There exists an incubation time for the onset of the healing of a crack, which is associated with local temperature at the crack tip. The crack size decreases with increasing the pulsing time at a constant healing rate prior to complete healing of the crack. Increasing compressive load accelerates the healing process. The electric pulsing leads to the formation of an influential zone surrounding the crack with the finest grain sizes in the healed crack and the coarsest …

Dual Light Emission Of Cssni3-Based Powders Synthesized Via A Mechanochemical Process, Xuan Huang, Xiaobing Tang, Xiyu Wen, Yuebin Charles Lu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Lead toxicity has hindered the wide applications of lead halide perovskites in optoelec- tronics and bioimaging. A significant amount of effort has been made to synthesize lead-free halide perovskites as alternatives to lead halide perovskites. In this work, we demonstrate the feasibility of synthesizing CsSnI3-based powders mechanochemically with dual light emissions under ambi- ent conditions from CsI and SnI2 powders. The formed CsSnI3-based powders are divided into CsSnI3-dominated powders and CsSnI3-contained powders. Under the excitation of ultraviolet light of 365 nm in wavelength, the CsSnI3-dominated powders emit green light with a wavelength centered at 540 nm, and the CsSnI3-contained powders …

Free And Forced Vibrations Of Elastically Restrained Cantilever With Lumped Oscillator, Alireza Babaei, Johné Parker, Paria Moshaver

Earth and Environmental Sciences Faculty Publications

The efficiency assessment of cantilever-based energy harvesters relies on vibrational analysis, which necessitates modi- fications aimed at enhancing efficiency. These modifications involve manipulating the fundamental frequency to lower values and encompassing a wider range of resonances within a specified bandwidth. Consequently, this paper introduces an original analytical-numerical exploration into the vibratory response of a cantilever with a novel boundary condi- tion involving an elastically restrained oscillator-spring arrangement. At the microbeam’s tip, an oscillator is elastically confined by a linear spring, resulting in a novel set of coupled governing equations and a distinct shearing boundary condition. Microbeam equations is derived from …

Effects Of Ferrite And Graphite Phases On Scratch Characteristics Of Nodular Cast Iron, Zhitong Xu, Ming Liu, Chenghui Gao, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this work, we conduct micro-scratch tests of nodular cast iron with Vickers indenter under constant normal load and investigate the effects of individual phases (i.e., ferrite and graphite phases) on the scratch charac- teristics of nodular cast iron. Using a bimodal Gaussian model to fit the experimental data of penetration depth, residual depth, elastic recovery rate, and scratch hardness, we calculate the contribution percentages of indi- vidual phases to scratch variables. The scratch variables are independent of the scratch speed used in this work, while the penetration depth increases linearly with increasing the normal load. There exists a large …