Materials Science and Engineering Commons^™

Modeling Hierarchical Porous Electrodes With Tailored Anisotropic Structure, Debanjan Sarker

All Theses

Modern electric vehicles and consumer electronics applications demand high specific energy from Li-ion batteries, which can be charged and discharged faster. In the search for high specific energy, researchers have tried to make thicker battery electrodes which contain a greater proportion of active material. While chemical and structural modification of electrodes can help to increase the electronic conductivity of active material, the microstructure of porous electrodes can be engineered to enhance ion transport for fast charge and discharge. Previous research has shown that macropores introduced by directional freeze tape casting can enhance the performance of thick porous electrodes. For instance, …

Manufacturing And Characterization Of Continuous Nanofiber-Reinforced Composites, Lucas Barry

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fiber-reinforced composite laminates are some of the most advanced structural materials available. However, delamination remains a critical challenge due to its prevalence in structures and ability to cause catastrophic failure. Recently, high-temperature composites are at the forefront of polymer-matrix composites research, but they are prone to microcracking followed by delamination. Nanoreinforcement of interfaces by continuous nanofibers has been proposed earlier at UNL and produced increased interlaminar fracture resistance in conventional advanced composites. However, no studies have yet been conducted on emerging high-temperature composites. Also, there is insufficient information on the translatability of observed modes I and II interlaminar fracture toughness …

Quantifying The Workability Of Calcium Sulfoaluminate Cement Paste Using Time-Dependent Rheology, Sukanta K. Mondal, Adam Welz, Carrie Clinton, Kamal Khayat, Aditya Kumar, Monday Uchenna Okoronkwo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Poor workability is a common feature of calcium sulfoaluminate (CSA) cement paste. Multiple chemical admixtures, such as set retarders and dispersants, are frequently employed to improve the workability and delay the setting of CSA cement paste. A quantitative assessment of the compatibility, efficiency, and the effects of the admixtures on cement paste workability is critical for the design of an appropriate paste formulation and admixture proportioning. Very limited studies are available on the quantitative rheology-based method for evaluating the workability of calcium sulfoaluminate cement pastes. This study presents a novel and robust time-dependent rheological method for quantifying the workability of …

Xps And Ipe Determination Of Band Offsets Of Germanium Based Materials, Justin Michael Rudie

Graduate Theses and Dissertations

Germanium tin and silicon germanium tin are group IV semiconductor alloys that have gained significant interest in recent years for their potential use in optoelectrical devices. While silicon and germanium are indirect bandgap materials on their own, alloying them with tin in sufficient quantities leads to a transition to direct bandgap alloys. Direct gap performance opens the door for efficient light emitting and detecting devices fabricated entirely on group IV materials that are compatible with the industry standard CMOS manufacturing techniques. Germanium tin and silicon germanium tin have bandgaps that respond to light in the mid to near infrared spectrum …

Study Of Thin Gan/Ingan/Gan Double Graded Structures For Future Photovoltaic Application, Mirsaeid Sarollahi

Graduate Theses and Dissertations

Indium gallium nitride (In_x Ga_(1-x) N) materials have displayed great potential for photovoltaic and optoelectronic devices due to their optical and electrical properties. Properties such as direct bandgap, strong bandgap absorption, thermal stability and high radiation resistance qualify them as great materials for photovoltaic devices. The tunable bandgap which absorbs the whole solar spectrum is the most significant feature which became attractive for scientists. The bandgap for these materials varies from 0.7 eV for InN to 3.4 eV for GaN covering from infrared to ultraviolet. In_x Ga_(1-x) N wurtzite crystal is grown on GaN buffer layer by Molecular Beam Epitaxy …

Effect Of Boron In Cast Iron, Suyash Durendra Pawaskar

Masters Theses

"Boron, mostly considered a residual element, has started to cause issues in the cast iron foundries by causing a decrease in the strength of pearlitic gray and ductile iron castings. Because of the increase in the use of boron-added steel scrap from automotive steel and a lack of agreement on the critical levels of boron in cast iron, foundries are facing difficulties in controlling the microstructure of gray iron castings when boron is present. The current investigation was designed to analyze the effects of boron in cast irons and predict a mechanism to understand its effects with a vision of …

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. …

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, …

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 …

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 …

61st Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 61st annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Copper Mountain, Colorado, July 25-29, 2022.

Development Of A Decellularized Hydrogel Composite And Its Application In A Novel Model Of Disc-Associated Low Back Pain In Female Sprague Dawley Rats, David Lillyman

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Chronic low back pain is a global socioeconomic crisis compounded by an absence of reliable, curative treatments. The predominant pathology associated with chronic low back pain is degeneration of intervertebral discs in the lumbar spine. During degeneration, nerves can sprout into the intervertebral disc tissue and be chronically subjected to inflammatory and mechanical stimuli, resulting in pain. Pain arising from the intervertebral disc, or disc-associated pain, is a complex, multi-faceted disorder which necessitates valid animal models to screen therapeutics and study pathomechanisms of pain.

While many research teams have created animal models of disc degeneration, the translation of these platforms …

Flow In Additively Manufactured Super-Rough Channels, Samuel Altland, Xiaowei Zhu, Stephen Mcclain, Robert Kunz, Xiang Yang

Mechanical and Materials Engineering Faculty Publications and Presentations

Metal additive manufacturing has enabled geometrically complex internal cooling channels for turbine and heat exchanger applications, but the process gives rise to large-scale roughness whose size is comparable to the channel height (which is 500 μm). These super-rough channels pose previously unseen challenges for experimental measurements, data interpretation and roughness modelling. First, it is not clear if measurements at a particular streamwise and spanwise location still provide accurate representation of the mean (time- and plane-averaged) flow. Second, we do not know if the logarithmic layer survives. Third, it is unknown how well previously developed rough-wall models work for these large-scale …

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 …

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 …

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 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), …

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 …