Engineering Science and Materials Commons^™

Machinability Of High Mn Steel Using Tool Life Criteria, Dika Handayani, Victor F. Okhuysen, Nicole Wagner

Engineering Faculty Articles and Research

High Mn steel alloys have shown to provide both high strength and ductility. However, current literature offers limited guidance on the machinability of these steel alloys. Therefore, this work provides turning recommendations for high Mn steel that is based on tool life data. Several indexable carbide inserts with various rake angles were used to machine cast billets of high Mn steel. Turning characteristics from various feed rates, cutting speeds, and depths of cut were analyzed. Through a design of experiments, it was determined that the feed rate was the most significant factor affecting tool life and that a tool with …

Enhancing Compatibility And Mechanical Properties Of Natural Rubber Composites, Krisma Yessi Sianturi, Adam Febriyanto Nugraha, Belle Kristaura, Mochamad Chalid

Journal of Materials Exploration and Findings

Pure natural rubber (NR) exhibits low mechanical properties, necessitating the incorporation of additives like vulcanizing agents and fillers. Carbon black and silica, conventional fillers, are relatively expensive and not environmentally friendly. This study explores using Oil Palm Empty Fruit Bunch (OPEFB) fiber as an affordable, abundant, and biodegradable alternative filler for NR. However, compatibility issues arise between the nonpolar NR and the polar OPEFB fiber. A latex-starch hybrid coupling agent (CA (NR-St)) was added to the composite formulation to address this. NR, OPEFB fiber, and the coupling agent were mixed using an open roll mill with a 10 phr OPEFB …

Mesoscale Modeling And Machine Learning Studies Of Grain Boundary Segregation In Metallic Alloys, Malek Alkayyali

All Dissertations

Nearly all structural and functional materials are polycrystalline alloys; they are composed of differently oriented crystalline grains that are joined at internal interfaces termed grain boundaries (GBs). It is well accepted that GB dynamics play a critical role in many phenomena during materials processing or under operating environments. Of particular interest are GB migration and grain growth processes, as they influence many crystal-size dependent properties, such as mechanical strength and electrical conductivity.

In metallic alloys, GBs offer a plethora of preferential atomic sites for alloying elements to occupy. Indeed, recent experimental studies employing in-situ microscopy revealed strong GB solute segregation …

Characterization Of Novel Self-Healing Polymer Blends For Additive Manufacturing, Truman James Word

Open Access Theses & Dissertations

This dissertation begins with an overview of novel polymer systems which have been developed by the Polymer Extrusion Lab at the University of Texas at El Paso. Many composite polymer systems have been created using many different polymers as well as ceramics and metals primarily in the form of powders added to the bulk polymer. The bulk of this work entails a study that was conducted to develop and characterize the mechanical, shape memory and self-healing properties of three polymer blends: polylactic acid (PLA) combined with maleated styrene-ethylene-butylene-styrene (SEBS-g-MA), acrylonitrile butadiene styrene (ABS) combined with maleated styrene-ethylene-butylene-styrene (SEBS-g-MA), and polylactic …

Assessment Of Bridge Pier Response To Fire, Vehicle Impact, And Air Blast, Chen Fang, Qusai Alomari, Daniel G. Linzell

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Highway bridges exposed to intentional or unintentional fire followed by combined vehicle impact and air blast are at risk of significant damage and, possibly, collapse. Limited studies examining the complex effects of these extreme demands on bridge support elements and parametrizing their response and damage are found in the open literature. Research that is presented is part of an ongoing numerical investigation examining round, multi-column, reinforced concrete (RC), bridge pier behavior subject to multi-hazard scenarios involving fire, vehicle impact, and air blast. Detailed nonlinear finite element analysis models of single columns and multi-column piers supported by a pile foundation system …

High-Yield Bioinspired Atmospheric Water Capture Through Hydrogels, Yiwei Gao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Water scarcity is a global issue affecting billions of people, and atmospheric water harvesting (AWH) technology has been identified as a potential solution. However, existing single-material AWH approaches have limited water harvesting yields due to alternated water capture, storage, and release stages, and only function within a high relative humidity range. In my doctoral research project, we developed a bio-inspired, hydrogel-based multi-layer AWH approach that allows for segregated capture, storage, and release stages, and is envisioned to have higher daily water harvesting efficiency even in low-humidity areas. My research began with understanding the relations between hydrogel mechanical stiffness, hydraulic permeability, …

Spectroscopic Studies On Silicon And Chalcopyrite Materials For Solar Energy Applications, Amandee Hua

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this dissertation, silicon-based materials for photovoltaics and chalcopyrite-based materials for photoelectrochemical water splitting are investigated using various spectroscopic and microscopic techniques. Although silicon dominates the photovoltaic market, further improvement can be made by using an alternative low temperature passivation approach. Currently, thermally grown SiO2 passivation is commonly used for silicon solar cells. However, this technique requires high processing temperatures (>800 °C), which increases the thermal budget, potentially decreases the bulk quality of Si, and can lead to difficulties in implementing in production lines. Here, a S-based passivation approach is studied that require lower processing temperatures of ~550 °C. …

Machine Learning-Based Data And Model Driven Bayesian Uncertanity Quantification Of Inverse Problems For Suspended Non-Structural System, Zhiyuan Qin

All Dissertations

Inverse problems involve extracting the internal structure of a physical system from noisy measurement data. In many fields, the Bayesian inference is used to address the ill-conditioned nature of the inverse problem by incorporating prior information through an initial distribution. In the nonparametric Bayesian framework, surrogate models such as Gaussian Processes or Deep Neural Networks are used as flexible and effective probabilistic modeling tools to overcome the high-dimensional curse and reduce computational costs. In practical systems and computer models, uncertainties can be addressed through parameter calibration, sensitivity analysis, and uncertainty quantification, leading to improved reliability and robustness of decision and …

The Study Of Corrosion On Additive-Manufactured Metals., Braydan Daniels

Electronic Theses and Dissertations

The purpose of this study was to investigate and compare the corrosion mechanisms between wrought and additive-manufactured (3D-printed) copper and stainless steel. The experimental procedure consisted of measuring the open circuit potential, electrochemical impedance spectroscopy, linear sweep voltammetry, Tafel analysis, surface topology, and scanning electron microscopy for each metal within salt water, tap water, sulfuric acid, and synthetic body fluid (excluding copper in synthetic body fluid).

Overall, printed stainless steel was more corrosion-resistant than wrought stainless steel in tap water and synthetic body fluid based on OCP, LSV, and surface topology results. Additionally, printed copper was more corrosion-resistant than wrought …

Thermal Behavior Of Plain And Fiber-Reinforced Rigid Concrete Airfield Runways, Arash Karimi Pour

Open Access Theses & Dissertations

The environmental condition and temperature gradient are important factors resulting in concrete airfield runways cracking during the time. Rigid concrete airfield runways experience different thermal gradients during the day and night due to changes in air temperature. Curling and thermal expansion stresses are the main consequences resulting in various types of cracking over the surface and thickness of concrete airfield runways and increasing maintenance costs. The curvature of concrete slabs increases with an increase in the temperature gradient which is amplified when runways open to traffic. Additionally, the combination of the curling and shrinkage stresses, in rare circumstances, can be …

Metastability And Degradation In Cu(In,Ga)Se2 Thin-Film Solar Cells, Mohsen Jahandardoost

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cu(In,Ga)(S,Se)2 or CIGS is a thin-film semiconductor that has shown a device efficiency of 23.35% and 24.2% for single-junction and perovskite/CIGS tandem solar cells, respectively. CIGS offers promising properties such as tunable bandgap and ease of processing making them great candidates for thin-film tandem devices. However, knowledge of the effect of material defects, buffer materials, and post-deposition treatment (PDT) on degradation and metastability behavior in these devices is not well understood.In this dissertation, metastability and long-term degradation of CIGS thin-film solar cells have been investigated under combinatorial stress factors of heat, light, and voltage bias to systematically understand the effect …

Me-Em Enewsbrief, March 2023, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Classification Of Electrical Current Used In Electroplastic Forming, Tyler Grimm

All Dissertations

Electrically assisted manufacturing (EAM) is the direct application of an electric current to a workpiece during manufacturing. This advanced manufacturing process has been shown to produce anomalous effects which extend beyond the current state of modeling of thermal influences. These purported non-thermal effects have collectively been termed electroplastic effects (EPEs).

While there is a distinct difference in results between steady-state (ideal DC) testing and pulsed current testing, the very definition of these two EAM methods has not been well established. A "long" pulse may be considered DC current; a "short" pulse may produce electroplastic effects; and even "steady-state" current shapes …

The Effects Of Laser Shock Peening On The Fatigue Life Of Additive Manufactured Alsi10mg, Jacob L. Biddlecom

All Dissertations

Additive manufacturing (AM) is becoming a manufacturing process that is well established, even with all the resources and attention that has been brought to it, the field is still lacking some key understandings. Currently, there are certain aspects that are difficult to overcome. Some of the intrinsic obstacles include process-induced defects, such as porosity from lack of fusion and gaseous bubble entrapment, as well as complex thermal gradients. These defects can lead to altered material response especially when looking at the fatigue life. The fatigue behaviors of AM components can change from print to print as well as when compared …

Preface To The Special Issue On Lithium-Sulfur Batteries, Jia-Jia Chen, Ren-Jie Chen, Zhong Jin

Journal of Electrochemistry

No abstract provided.

Cobalt/Carbon Composites As Sulfur Hosts For High-Performance Lithium-Sulfur Batteries, Yun-Rui Yang, Huan-Huan Dong, Zhi-Qiang Hao, Xiang-Xi He, Zhuo Yang, Lin Li, Shu-Lei Chou

Journal of Electrochemistry

Lithium-sulfur (Li-S) battery is one of the promising energy storage devices because of its high energy density. However, the sulfur cathode suffers from sluggish electrochemical reaction kinetics, slow charge transfer, large volume expansion and severe shuttle effect of lithium polysulfides inevitably resulting in low reversible capacity, poor rate performance and short cycle life, limiting its practical applications. Herein, the recent progress of cobalt/carbon composites, including cobalt nanoparticles and cobalt single atoms, as the sulfur host materials in Li-S batteries is overviewed. In general, cobalt plays the role of electrocatalyst, which inhibits the shuttle effect of lithium polysulfides, accelerates the electrochemical …

Recent Advances Of Functional Electrolyte Additives For Lithium-Sulfur Batteries, Xiu-Qing Zhang, Shuai Tang, Yong-Zhu Fu

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries have become one of the most promising next-generation battery systems due to their high energy density and low cost. However, the application of Li-S batteries still faces critical challenges, such as the low conductivities of S and Li₂S, shuttle effect of polysulfides and dendrite growth of Li, etc. The optimization of the electrolyte can ameliorate the electrolyte|electrode interphase, conveniently regulating the parasitic reaction and improving the performance of the resultant batteries. The functional additives in electrolytes provide chances to tune the interphase and even the redox mechanism to improve the performance of the batteries. In …

Metals And Alloys As Catalytic Hosts Of Sulfur Cathode For Lithium-Sulfur Batteries, Zhen-Yu Wang, Xue-Ping Gao

Journal of Electrochemistry

Lithium-sulfur batteries are recognized as one of the most promising next-generation energy storage devices, owing to the high theoretical energy density of 2600 Wh·kg^–1. However, their application has been seriously hindered by the sluggish electrochemical reaction kinetics of elemental sulfur and discharged products (Li₂S₂/Li₂S), and the notorious “shuttle effect” of soluble intermediate lithium polysulfide species, leading to poor cycle stability, low sulfur utilization and inferior coulombic efficiency. Introducing catalytic hosts into sulfur cathode is an efficient path to propel the conversion of sulfur-contained species, thus preventing the dissolution and loss of active-sulfur …

Ultraviolet-Initiated In-Situ Cross-Linking Of Multifunctional Binder Backbones Enables Robust Lithium-Sulfur Batteries, Sha Li, Xiao Zhan, Gu-Lian Wang, Hui-Qun Wang, Wei-Ming Xiong, Li Zhang

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries show attractive prospects owing to their high theoretical energy density, but their commercialization still faces such challenges as lithium polysulfides shuttling, severe volume change and considerable polarization. These stubborn issues place higher demands on each component in the battery, such as the development of multifunctional binders with superior mechanical properties. Herein, ethoxylated trimethylolpropane triacrylate was firstly introduced into sulfur cathodes, and in-situ cross-linked by ultraviolet (UV) curing combined with traditional polyvinylidene difluoride binder (i.e., forming a binary binder, denoted as c-ETPTA/PVDF) to construct high-loading and durable Li-S batteries. The covalently cross-linked ETPTA framework not only significantly enhances …

Development Of A Fish Robot Equipped With Novel 3d-Printed Soft Bending Actuators, Steven Steele, Jorge Diaz Rodriguez, Sharun Sripathy, Turaj Ashuri, Saleh Gharaie, Yusun Chang, Amir Ali Amiri Moghadam

Symposium of Student Scholars

This paper reports on design and fabrication of a novel soft fish robot. Application of soft actuators for the fish tail will generates continuum bending motion which resembles the natural motion of the fish. However, most soft actuator mechanisms are complex and have low efficiency. Thus, to address this issue we have developed a 3D printed soft bending actuator which can be actuated with an electromotor. The basic design idea of the soft bending actuator is explained, and iteration of the design showed to create the desired motion for the soft tail. The soft actuator has been successfully integrated with …

Shape Memory Polymer-Based Multifunctional Syntactic Foams, Siavash Sarrafan

LSU Doctoral Dissertations

With the increase in popularity of shape memory polymers (SMPs), especially in applications such as aerospace, textile, biomedical engineering, and even structures, the weight of the material and the devices made with it has always been a crucial factor. Using the shape memory polymer as a matrix to make a syntactic foam is one of the best and most affordable approaches to creating a lighter material that still has the shape memory effect. The addition of particles of different stiffness, strength, and size, with variable fractions, creates a composite that enables engineering the mechanical, as well as other physical and …

Editorial: Disease Biomarker Analysis Based On Optical Biosensing, Tianshu Chen, Fanben Meng, Binwu Ying, Xiaoli Zhu

Department of Mechanical and Materials Engineering: Faculty Publications

Disease biomarker analysis has become a crucial tool for diagnosing and evaluating disease prognosis, especially with the increasing understanding of diseases at the molecular level. Abnormalities in various biomarkers can indicate diseased states, and can be used to rapidly and specifically detect and quantify diseases using optical biosensing techniques (Gao et al., 2023). Optical biosensing techniques have several advantages over traditional methods including higher sensitivity, specificity, and faster analysis times (Plikusiene and Ramanaviciene, 2023). It also allows for non-invasive sample collection. With advancements in optical biosensing technology, many medical conditions including cancers, infectious diseases, and autoimmune disorders can be accurately …

Editorial: Disease Biomarker Analysis Based On Optical Biosensing, Tianshu Chen, Fanben Meng, Binwu Ying, Xiaoli Zhu

Department of Mechanical and Materials Engineering: Faculty Publications

Disease biomarker analysis has become a crucial tool for diagnosing and evaluating disease prognosis, especially with the increasing understanding of diseases at the molecular level. Abnormalities in various biomarkers can indicate diseased states, and can be used to rapidly and specifically detect and quantify diseases using optical biosensing techniques (Gao et al., 2023). Optical biosensing techniques have several advantages over traditional methods including higher sensitivity, specificity, and faster analysis times (Plikusiene and Ramanaviciene, 2023). It also allows for non-invasive sample collection. With advancements in optical biosensing technology, many medical conditions including cancers, infectious diseases, and autoimmune disorders can be accurately …

Considering The Influence Of Coronary Motion On Artery‑Specific Biomechanics Using Fluid–Structure Interaction Simulation, Nicholas A. T. Fogell, Miten Patel, Pan Yang, Roosje M. Ruis, David B. Garcia, Jarka Naser, Fotios Savvopoulos, Clint Davies Taylor, Anouk L. Post, Ryan M. Pedrigi, Ranil De Silva, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

The endothelium in the coronary arteries is subject to wall shear stress and vessel wall strain, which influences the biology of the arterial wall. This study presents vessel-specific fluid–structure interaction (FSI) models of three coronary arteries, using directly measured experimental geometries and boundary conditions. FSI models are used to provide a more physiologically complete representation of vessel biomechanics, and have been extended to include coronary bending to investigate its effect on shear and strain. FSI both without- and with-bending resulted in significant changes in all computed shear stress metrics compared to CFD (p = 0.0001). Inclusion of bending within …

A Threshold Helium Leakage Detection Switch With Ultra Low Power Operation, Sulaiman Mohaidat, Fadi M. Alsaleem

Department of Mechanical and Materials Engineering: Faculty Publications

Detecting helium leakage is important in many applications, such as in dry cask nuclear waste storage systems. This work develops a helium detection system based on the relative permittivity (dielectric constant) difference between air and helium. This difference changes the status of an electrostatic microelectromechanical system (MEMS) switch. The switch is a capacitive-based device and requires a very negligible amount of power. Exciting the switch’s electrical resonance enhances the MEMS switch sensitivity to detect low helium concentration. This work simulates two different MEMS switch configurations: a cantilever-based MEMS modeled as a single-degreefreedom model and a clamped-clamped beam MEMS molded using …

Leipzig Applicator Dose Study Progress And Mesh Computational Phantoms, Julianna Davis

Undergraduate Research Competition

Leipzig applicators are tools used to administer brachytherapy, which is a treatment for skin cancer that is typically used when it occurs on the face of the patient. This treatment requires the patient to have lead shielding over their eyes to protect the sensitive lenses. This study is in the progress of modeling this scenario in order to determine the radiation dose delivered to the patient’s eyes due to the lead shielding. This is being done in a Monte Carlo computational radiation transport program, EGS (Electron Gamma Shower,) which was previously unable to handle mesh computational phantoms. After working with …

A High-Strength Precipitation Hardened Cobalt-Free High-Entropy Alloy, Matthew Luebbe, Jiaqi Duan, Fan Zhang, Jonathan Poplawsky, Hans Pommeranke, Maalavan Arivu, Andrew Hoffman, Mario Buchely, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Recent studies on precipitation-hardened high-entropy alloys (HEAs) demonstrate their high strength and thermal stability, making them promising materials for high-temperature structural applications such as nuclear reactors. However, many existing HEAs contain cobalt (Co), which is unsuitable for nuclear applications because of the long-term activation issue of Co. Co is also expensive and considered a critical material for other applications. Therefore, it is desired to exclude Co from the composition. a Co-free (Fe0.3Ni0.3Mn0.3Cr0.1)88Ti4Al8 HEA was developed and studied in this work. in contrast to previous Co-free HEAs, this alloy is close to Equi atomic in its composition and promises a more …

Development Of Novel Electrodes And Electrolytes For Safer Aqueous Ammonium Ion Batteries With Enhanced Performance., Shelton Farai Kuchena

LSU Doctoral Dissertations

The Lithium-ion battery (LIBs) system has dominated the battery market because of its superior energy and power density. Problems related to LIBs such as safety, scarcity of cobalt and lithium have led researchers to explore alternative battery systems. NH₄⁺ ion is a nonmetal charge carrier with lower molar mass (18 mol g^-1) and smaller hydrated ionic size (3.31 Å) which results in excellent electrochemical properties. Furthermore, NH₄⁺ ion has a tetrahedral structure that has no preferred orientation as compared to spherical metal ions giving a different intercalation chemistry based on hydrogen bonding. These properties …

Crystalline–Amorphous Nanostructures: Microstructure, Property And Modelling, Binqiang Wei, Lin Li, Lin Shao, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Crystalline metals generally exhibit good deformability but low strength and poor irradiation tolerance. Amorphous materials in general display poor deformability but high strength and good irradiation tolerance. Interestingly, refining characteristic size can enhance the flow strength of crystalline metals and the deformability of amorphous materials. Thus, crystalline–amorphous nanostructures can exhibit an enhanced strength and an improved plastic flow stability. In addition, high-density interfaces can trap radiation-induced defects and accommodate free volume fluctuation. In this article, we review crystalline–amorphous nanocomposites with characteristic microstructures including nanolaminates, core–shell microstructures, and crystalline/amorphous-based dual-phase nanocomposites. The focus is put on synthesis of characteristic microstructures, deformation …

Beirut Arab University - Faculty Of Engineering - Newsletter Issue 0, Faculty Of Engineering, Beirut Arab University

Engineering Newsletters

No abstract provided.