Engineering Science and Materials Commons^™

A Co Porphyrin With Electron-Withdrawing And Hydrophilic Substituents For Improved Electrocatalytic Oxygen Reduction, Hong-Bo Guo, Ya-Ni Wang, Kai Guo, Hai-Tao Lei, Zuo-Zhong Liang, Xue-Peng Zhang, Rui Cao

Journal of Electrochemistry

Understanding factors that influence the catalyst activity for oxygen reduction reaction (ORR) is essential for the rational design of efficient ORR catalysts. Regulating catalyst electronic structure is commonly used to fine-tune electrocatalytic ORR activity. However, modifying the hydrophilicity of catalysts has been rarely reported to improve ORR, which happens at the liquid/gas/solid interface. Herein, we report on two Co porphyrins, namely, NO₂-CoP (Co complex of 5,10,15,20-tetrakis(4-nitrophenyl)porphyrin) and 5F-CoP (Co complex of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin), and their electrocatalytic ORR features. By simultaneously controlling the electronic structure and hydrophilic property of the meso-substituents, the NO₂-CoP showed higher electrocatalytic activity than …

Influence Of Defects On In-Plane Dynamic Properties Of Hexagonal Ligament Chiral Structures, Ning An, Xunwen Su, Dongmei Zhu, Mileta M. Tomovic

Engineering Technology Faculty Publications

Although the six-ligament chiral structure has many unique properties, due to its special structure, the stress concentration is prone to defects. In addition, additive manufacturing is also prone to defects. This paper studies the effect of defects, which is helpful for the better application of the six-ligament chiral structure. Several new six-ligament chiral structures with random and concentrated defects were designed to explore the effects of the defects on the in-plane dynamic properties. The structures were studied with the finite element ANSYS/LSDYNA numerical simulation and experimental methods. According to the defect-free six-ligament chiral structures exhibiting different deformation modes at different …

Quantitative Lithium Composite As 3d Lithium Foam Anode For Lithium Metal Battery, Hu-Dong Li, Wei-Shang Jia, Xin-Xiu Yan, Yao-Yue Yang

Journal of Electrochemistry

Lithium (Li) metal as an anode material for batteries has extremely high specific capacity and extremely low redox potential, which can significantly improve the energy density of the battery. However, the main problems faced by the use of Li metal anodes are Li dendrite growth, interfacial side reaction and volumetric change of electrode. Herein, a strategy to prepare the three-dimensional (3D) Li foam by combining 3D scaffold with quantitative Li was proposed to suppress Li dendrites growth and alleviate electrode volumetric change. The 3D Li foam facilitated the efficient utilization of Li metal by suppressing the Li dendrite growth, mitigating …

Low-Crystallinity And Heterostructured Aupt-Ru@Cnts As Highly Efficient Multifunctional Electrocatalyst, Tuan-Jie Gan, Jian-Ping Wu, Shi Liu, Wen-Jun Ou, Ling Bin, Xiong-Wu Kang

Journal of Electrochemistry

The catalytic activity of the catalysts is strongly dependent on the structure of the catalysts, and the exploration of their correlation and structure-controlled synthesis of the high-performance catalysts are always at the central. Currently, platinum (Pt) is the optimum catalyst for hydrogen evolution reaction (HER), oxygen reduction reaction (ORR) and alcohol oxidation reaction, while ruthenium (Ru) behaves as the champion catalyst for oxygen evolution reaction (OER) during water splitting. Preparing alloy catalysts with these precious metals can modulate the catalytic activity of these catalysts from the perspective of strain effect, ensemble effect and ligand effect. Here, we developed a strategy …

Optimized Electrochemical Performance Of Si@C Prepared By Hydrothermal Reaction And Glucose Carbon Source, Si Chen, Song-Sheng Zheng, Lei-Ming Zheng, Ye-Han Zhang, Zhao-Lin Wang

Journal of Electrochemistry

Silicon (Si) has been considered as the potential material for the next-generation lithium-ion batteries (LIBs) for its high capacity (4200 mAh·g^-1, Li₂₂Si₅) and suitable working voltage (about 0.25 V vs. Li/Li⁺). However, the cycling stability and electrochemical performance of Si anode become significant challenges because of low intrinsic conductivity and huge volume variation (about 400%) during cycling processes. In addition, the repeated formation and destruction of surface solid electrolyte interphase (SEI) film will continuously consume the electrolyte and cause damage to LIBs. Carbon (C) materials, such as graphite, carbon spheres and tubes, …

Facile One-Step Solid-State Synthesis Of Ni-Rich Layered Oxide Cathodes For Lithium-Ion Batteries, Jing-Yue Wang, Rui Wang, Shi-Qi Wang, Li-Fan Wang, Chun Zhan

Journal of Electrochemistry

Nickel-rich layered oxide is one of the dominate cathode materials in the lithium ion batteries, due to its high specific energy density meeting the range requirement of the electric vehicles. Typically, the commercial Ni-rich layered oxides are synthesized from co-precipitated precursors, while precision control is required in the co-precipitation process to ensure the atomic level mixing of the cations such as Ni, Co and Mn, et.al. In this work, a one-step solid-state method was successfully applied to synthesize the Ni-rich layered oxide materials with ultra-high Ni content. By choosing the nickel hydroxides as the precursor with layered structure similar to …

Modeling The Effects Of Mechanical Loading On Hypertrophic Cardiomyopathy Pathogenesis In Human Induced Pluripotent Stem Cell Derived Micro Heart Muscle, Jingxuan Guo

McKelvey School of Engineering Graduate Student Theses & Dissertations

Sudden cardiac death in the young is devastating. Advances in genetics have associated mutations in the contractile sarcomere apparatus of cardiomyocytes with hypertrophic cardiomyopathy, the most frequent cause of sudden cardiac death in the young. Currently, it is challenging to predict genotype-phenotype relationships in hypertrophic cardiomyopathy due to its incomplete disease penetrance. For example, different patients from the same family with identical genomic variants develop different symptoms. Non-genetic, environmental factors such as blood pressure are critical in heart function and disease. Therefore, understanding how mechanical factors contribute to phenotypes in diseases like hypertrophic cardiomyopathy is critical for developing effective therapeutics. …

Synthesis And Consolidation Of Metal Oxide Nanocrystals Via Nonthermal Plasma, Austin Cendejas

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nonthermal plasmas offer a unique nonequilibrium environment that has been leveraged in a wide variety of applications in the fields of material processing, lighting, and waste management to name a few. In all of these cases, the plasma serves as a source of high energy electrons, ions, reactive gas species, and radicals that interact in several ways with surfaces brought into contact with the plasma. Specifically, nonthermal plasmas have been shown to be very successful in achieving continuous, high-throughput, monodisperse nanocrystals of a wide variety of materials. The crystallinity of nanoparticles synthesized in nonthermal plasmas can be attributed to the …

Plasmonic Nanomaterials-Based Point-Of-Care Biosensors, Rohit Gupta

McKelvey School of Engineering Graduate Student Theses & Dissertations

Point-of-care (POC) biosensors, although rapid and easy-to-use, are orders magnitude less sensitive than laboratory-based tests. Further they are plagued by poor stability of recognition element thus limiting its widespread applicability in resource-limited settings. Therefore, there is a critical need for realizing stable POC biosensors with sensitivity comparable to gold-standard laboratory-based tests. This challenge constitutes the fundamental basis of this dissertation work– to expand access to quality and accurate biodiagnostic tools. At the heart of these solutions lies plasmonic nanoparticles which exhibit unique optical properties which are attractive for label-free and labelled biosensors.Firstly, we improve the stability and applicability of label-free …

Soft Electronics And Sensors For Wearable Healthcare Applications, Li-Wei Lo

McKelvey School of Engineering Graduate Student Theses & Dissertations

Wearable electronics are becoming increasingly essential to personalized medicine by collecting and analyzing massive amounts of biological signals from internal organs, muscles, and blood vessels. Conventional rigid electronics may lead to motion artifacts and errors in collected data due to the mismatches in mechanical properties between human skin. Instead, soft wearable electronics provide a better platform and interface that can form intimate contact and conformably adapt to human skin. In this respect, this thesis focuses on new materials formulation, fabrication, characterization of low-cost, high sensitivity and reliable sensors for wearable health monitoring applications.

More specifically, we have studied the silver …

Design Of Multi-Principal Element Materials Using A Combination Of First-Principles Calculations And Machine Learning, Zhaohan Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Multiple-principal element materials, including alloys (MPEAs), oxides and other compounds combine several elements on a sub-lattice, which increases the configurational entropy and contributes to their thermodynamic stability. The vast combinatorial design space of multi-principal element materials gives rise to diverse microstructures and unprecedent combination of properties. It also poses a challenge—how to rapidly screen MPEAs with stability and properties for targeted applications. Furthermore, fundamental composition-structure-property relationships in MPEAs are currently missing. In this dissertation, I have used MPEAs as a representative system and investigated the role of chemical composition on their phase-stability and mechanical properties. With a combination of first-principles …

The Generation And Transport Of Charged Aerosols: Fundamental Study And Applications In Medicine And Energy Conversion, Hao Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

Charged aerosols have significant implications in the field of functional material synthesis, pharmaceutical coating, and drug delivery. Electrospray systems are an effective methodology for generating highly charged monodispersed droplets in the size range from nanometer to micrometer. The prediction of surface charge, size and morphology of nanoparticles resulting from charged droplets are highly required for the precise control of nanoparticle properties and their effective utilization. However, the evolution of charged droplet is not well understood due to the existence of coulombic fission and ion evaporation processes. Thus, the goal of this dissertation is to elucidate how the precursor properties and …

Crack Control And Bond Performance Of Alternative Coated Reinforcements In Concrete, Sachin Sreedhara

All Dissertations

Concrete cracking in structures is a ubiquitous problem which can lead to the deterioration of the structure. Other than affecting the strength aspect of a structure, cracking impacts the serviceability criteria as well. Although cracking phenomenon in any structure is highly inevitable, it has to be minimized in order to maintain a structure’s life effectively. Cracking in reinforced concrete structures is related to the bond strength developed between the bar and the concrete. It also depends on an ability of the bar to resist the stresses due to shrinkage to minimize the crack. Another important aspect is the resistance offered …

Etching Process Development For Sic Cmos, Weston Reed Renfrow

Graduate Theses and Dissertations

Silicon Carbide (SiC) is an exciting material that is growing in popularity for having qualities that make it a helpful semiconductor in extreme environments where silicon devices fail. The development of a SiC CMOS is in its infancy. There are many improvements that need to be made to develop this technology further. Photolithography is the most significant bottleneck in the etching process; it was studied and improved upon. Etching SiC can be a challenge with its reinforced crystal structure. Chlorine-based inductively coupled plasma (ICP) etching of intrinsic SiC and doped SiC, SiO2, and Silicon has been studied. A baseline chlorine …

Passive Prosthetic Ankle Design Based On Indonesian Anthropometry, Wahyu Dwi Lestari

Journal of Mechanical Engineering Science and Technology (JMEST)

Foot prosthesis is a replacement for the foot to overcome activity limitations due to disease, birth defects, accidents, or amputations. Many foot prosthetics have been developed in recent years to treat patients. However, prostheses on the market today have drawbacks, including their high price, lack of comfort, stiff ankles, and low durability. The main objective of this study is to develop an existing ankle-foot prosthesis design that approximates the resemblance of a human foot according to the anthropometry of Asians, especially Indonesians. This study contains the design of a prosthetic foot with a skin design model and a support core. …

Surface Quality Of Fe, Ni And Cr Added Hyper-Eutectic Al-Si Automotive Alloys Under Up-Milling And Down-Milling Operation, Akib Abdullah Khan, Mashiur Rahman Shoummo, Mohammad Salim Kaiser

Journal of Mechanical Engineering Science and Technology (JMEST)

Effect of the elements Fe, Ni, and Cr on the surface quality under machining of hyper-eutectic aluminiumbased Al-Si automotive alloys has been carried out as the elements improve the properties of this alloy. Machining is done on a horizontal type milling machine using a high-speed steel slab milling cutter in dry condition. Only the cutting speed varies throughout the experiment, while the machining feed and depth of cut remain fixed. The experimental results show that the addition of these alloying elements increases the roughness and hardness specially due to formation of Fe-rich intermetallic ��-����5��������. However, the needle-like ��-����5�������� has been …

Effect Of Variation Of Sic Mass Fraction On Mechanical Properties Of Al-Sic Composite Using Stir Casting Method, Sumarji Sumarji, Naufal Fardio Albajili, Mahros Darsin, Rahma Rei Sakura, Andi Sanata

Journal of Mechanical Engineering Science and Technology (JMEST)

Al-SiC is a composite composed of AA6061 as a matrix and SiC as a reinforcement particle. The variation of mass added will affect the mechanical properties of the composite because Al-SiC is hardenable, which means that its mechanical properties can be improved by adding the reinforcement component. However, an excessive portion of SiC leads to a decrease in mechanical properties. The purpose of this study was to find the optimal composition of the addition of SiC into the aluminium matrix to gain maximum tensile strength and hardness. The mass fraction variation that would be used in this composite was the …

Effect Of Homogenization Pressure On Bacterial Cellulose Membrane Characteristic Made From Pineapple Peel Waste, Muhamad Muhajir, Heru Suryanto, Yanuar Rohmat Aji Pradana, Uun Yanuhar

Journal of Mechanical Engineering Science and Technology (JMEST)

Many studies were conducted to maintain the environment by reducing the waste, especially pineapple peel waste. This study aims to explore the effect of various pressure of the homogenization process on bacterial cellulose membrane surface morphology and structure produced using extract of pineapple peel waste. The methods include the preparation of pellicle samples from the product of the fermentation process of Acetobacter xylinum using a medium from the extract of pineapple peel waste. Bacterial cellulose pellicles were crushed using a blender. Mashed bacterial cellulose pellicle was homogenized in High-Pressure Homogenizer with pressure variation of 150 bar, 300 bar, 450 bar, …

Machine Vision For The Various Road Surface Type Classification Based On Texture Feature, Susi Marianingsih, Widodo Widodo, Marla Sheilamita S. Pieter, Evanita Veronica Manullang, Hendry Y. Nanlohy

Journal of Mechanical Engineering Science and Technology (JMEST)

The mechanized ability to specify the way surface type is a piece of key enlightenment for autonomous transportation machine navigation like wheelchairs and smart cars. In the present work, the extracted features from the object are getting based on structure and surface evidence using Gray Level Co-occurrence Matrix (GLCM). Furthermore, K-Nearest Neighbor (K-NN) Classifier was built to classify the road surface image into three classes, asphalt, gravel, and pavement. A comparison of KNN and Naïve Bayes (NB) was used in present study. We have constructed a road image dataset of 450 samples from real-world road images in the asphalt, gravel, …

Gasohol Engine Performance With Various Ignition Timing, Hendry Y. Nanlohy, Suyatno Suyatno, Helen Riupassa, Marthina Mini, Trismawati Trismawati, Mebin Panithasan

Journal of Mechanical Engineering Science and Technology (JMEST)

Experimental research has been conducted on the effect of ignition timings on the characteristics and performance of gasohol engines such as power, torque, specific fuel consumption, and thermal efficiency. The fuel used in this research is pure gasoline and a mixture of 50% bioethanol (BE50). The results show that the ignition timing that gives the maximum effect occurs at the top and bottom dead points of 9 degrees for gasoline and 12 degrees for BE50 fuel. Furthermore, the maximum power is obtained at 6,500 rpm, and at an ignition time of 12 degrees BTDC the maximum power generated is 4.63 …

Research Progress Of Copper Electrodeposition Filling Mechanism In Silicon Vias, Yun-Na Sun, Yong-Jin Wu, Dong-Dong Xie, Han Cai, Yan Wang, Gui-Fu Ding

Journal of Electrochemistry

Aiming at the electroplating filling problem of deep via TSV (through silicon via) interconnection, the multi-compatible integrated manufacturing technology team at the Shanghai Jiao Tong University has completed the numerical solution of the equations and realized the numerical simulation of TSV filling mode by applying the finite element method with arbitrary Lagrange Euler algorithm. The filling mechanisms of blind vias, the butterfly filling form for the through vias and the simultaneous filling mode of vias with different aspect ratios are analyzed by simulation, contributing to the parameter optimization and sample manufacturing. The effects of electroplating current density and heat treatment …

Electrodeposition Of Functional Epitaxial Films For Electronics, Kui Huang, Rong-Jiao Huang, Su-Qin Liu, Zhen He

Journal of Electrochemistry

Electrodeposition is a solution-based synthesis technique that can be used to fabricate various functional materials on conductive or semiconductive substrates under ambient conditions. Electrodeposition is usually triggered by an artificial electric stimulation (i.e., applied potential/current) to the substrate to oxidize or reduce ions, molecules, or complexes in the deposition solution layer near the substrate surface, which drives this solution layer to depart from its thermodynamic equilibrium and consequently causes the assembly of targeted deposits on the substrate. During electrodeposition, many experimental parameters could affect the properties of the deposits in different ways. To date, many elements (both metals and nonmetals), …

Mechanism And Application Of Nickel Nano-Cone By Electrodeposition On A Flexible Substrate, Xiu-Ren Ni, Ya-Ting Zhang, Chong Wang, Yan Hong, Yuan-Ming Chen, Yuan-Zhang Su, Wei He, Xian-Ming Chen, Ben-Xia Huang, Zhen-Lin Xu, Yi-Feng Li, Neng-Bin Li, Yong-Jie Du

Journal of Electrochemistry

Nano-array structure possesses promising prospect in power supply, optical device and electronic manufacturing. In this paper, a black nickel nano-cone array was prepared on a flexible substrate by galvanostatic deposition and the corresponding factors involved in the fabrication of nickel nano-cone array was explored. Experimental results showed that a large current density and low main salt concentration were not favored to the formation of cone nickel structure. It was also found that ammonium chloride, as the crystal modifier, was crucial to deposit the uniform nano-cone array. In addition, the growth mechanism of nickel nano-cone was further studied by molecular dynamics …

Effect Of Corrosion Inhibitors On Copper Etching To Form Thick Copper Line Of Pcb In Acidic Etching Solution, Xiao-Li Wang, Wei He, Xian-Ming Chen, Hong Zeng, Yuan-Zhang Su, Chong Wang, Gao-Sheng Li, Ben-Xia Huang, Lei Feng, Gao Huang, Yuan-Ming Chen

Journal of Electrochemistry

The chemical compounds of 2-mercaptobenzothiazole (2-MBT), benzotriazole (BTA) and phenoxyethanol (MSDS) as corrosion inhibitors were used to inhibit the copper etching to form the thick copper line of PCB in the acidic etching solution. The inhibition status was characterized with contact angle measurement, electrochemical test and etch factor calculation, while the corrosion morphology of copper surface was studied by scanning electron microscope. The adsorption mechanism of corrosion inhibitors on copper surface is analyzed by molecular dynamics and quantum chemistry calculations. The results indicated that the synergistic function of the two inhibitors could effectively promote their adsorption on the copper surface …

Electrodeposition Mechanism And Process Of A Novel Cyanide-Free Gold Sulfite Bath, Jia-Qiang Yang, Lei Jin, Wei-Qing Li, Zhao-Yun Wang, Fang-Zu Yang, Dong-Ping Zhan, Zhong-Qun Tian

Journal of Electrochemistry

A novel cyanide-free gold sulfite process is introduced in this paper. In the bath, chloauric acid was directly employed as the main salt, and hydroxyethylidene diphosphonic acid (HEDP) was used as the stabilizer and coating grain refiner. The bath stability, the gold coating morphology and the mechanism of gold electrodeposition were studied in detail. The results showed that HEDP could significantly improve the bath stability. Moreover, the grains of the gold coating obtained from the gold sulfite bath without HEDP was rod-like, which grew gradually with the increasing of the deposition time, resulting in that the appearance of the coating …

Bbt Acoustic Alternative Top Bracing Cadd Data Set-Norev-2022jun28, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set consists of an overview presentation (PDF-formatted) file and companion video (MP4) and CADD files (DWG & DXF) for laser cutting the ETSU-developed alternate top bracing designs and marking templates for the STEM Guitar Project’s BBT (OM-sized) standard acoustic guitar kit. The three (3) alternative BBT top bracing designs in this release are
(a) a one-piece base for the standard kit's (Martin-style) bracing,
(b) 277 Ladder-style bracing, and
(c) an X-braced fan-style bracing similar to traditional European or so-called 'classical' acoustic guitars.

The CADD data set for each of the three (3) top bracing designs includes …

Study On Hydration Properties Of Grinded Tuff-Cement Cementitious Material System, Hao Wang

International Conference on Durability of Concrete Structures

The chemical composition and microscopic morphology characteristics of grinded tuff(GT) and fly ash(FA) were compared and analyzed in the paper. The chemical bound water content and hydration heat were tested for investigating the hydration properties of grinded tuff-cement cementitious material system (GTCS) and fly ash-cement cementitious material system (FACS). The results shown that, the chemical composition of GT was similar with that of FA, however the loss on ignition of the GT was obviously higher than FA. The microstructure of the GT particles was polygonal and irregular, while the microstructure of FA particles were mostly smooth spheres. The hydrated heat …

Effects Of Pulsatile Flow Rate And Shunt Ratio In Bifurcated Distal Arteries On Hemodynamic Characteristics Involved In Two Patient-Specific Internal Carotid Artery Sidewall Aneurysms: A Numerical Study, Hang Yi, Mark Johnson, Luke C. Bramlage, Bryan Ludwig, Zifeng Yang

Mechanical and Materials Engineering Faculty Publications

The pulsatile flow rate (PFR) in the cerebral artery system and shunt ratios in bifurcated arteries are two patient-specific parameters that may affect the hemodynamic characteristics in the pathobiology of cerebral aneurysms, which needs to be identified comprehensively. Accordingly, a systematic study was employed to study the effects of pulsatile flow rate (i.e., PFR−I, PFR−II, and PFR−III) and shunt ratio (i.e., 75:25 and 64:36) in bifurcated distal arteries, and transient cardiac pulsatile waveform on hemodynamic patterns in two internal carotid artery sidewall aneurysm models using computational fluid dynamics (CFD) modeling. Numerical results indicate that larger PFRs can cause higher wall …

Effect Of Dispersions Of Al2o3 On The Physical And Mechanical Properties Of Pure Copper And Copper-Nickel Alloy, Samah El-Khatib, A. H. Elsayed, A. Y. Shash, A. El-Habak

Future Engineering Journal

This paper illustrates the mechanical and physical properties of pure Cu and Cu-Ni (50-50 wt. %) alloy mixed with Al₂O₃ (1-4 wt. %) as micro-particles reinforcement materials. The attained composite alloy specimens' characteristics were estimated such as microstructure, relative density, electrical and thermal conductivity, hardness, and compression yield stress properties to adjust the suitable optimum percentage of reinforcing material which has the best physical and mechanical properties with different main matrix materials whether pure Cu powder or Cu-Ni mechanical alloy. The micron-sized Al₂O₃ was added to enhance the mechanical and physical properties of the …

Study On The Effect Of Additives In The Electrodeposition Of Sn-Ag-Cu Ternary Alloy Solder, Hua Miao, Ming-Rui Li, Wen-Zhong Zou, Guo-Yun Zhou, Shou-Xu Wang, Xiao-Jing Ye, Kai Zhu

Journal of Electrochemistry

Sn-Ag-Cu ternary alloy is the most ideal substitute for Sn-Pb alloy at present, and can be prepared by electrodeposition with high production efficiency, simple equipment, easy maintenance and excellent coating performance. The coordination system of the electroplating solution was investigated through the Hull cell experiment. The type of brighteners used in the plating solution and the ratio of the two brighteners were determined through the microscopic morphologic characterization, electrochemical corrosion test and cathodic polarization curve test. In addition, the dispersant and stabilizer were studied by observing the microscopic morphology and measuring the concentration change of Sn²⁺ ions in the …