Engineering Science and Materials Commons^™

The Effect Of Thickness And Type Of Material On The Sheared Edge Characteristics Of Keychain Cranioplasty Plate Blanking Product Using Eccentric Press Machine, Didin Zakariya Lubis, Lea Rachmat Indrasepta, Redyarsa Dharma Bintara, Rizky Ramadhan, Agung Budi Darmawan

Journal of Mechanical Engineering Science and Technology (JMEST)

Keychain cranioplasty plate product has the potential to be produced using the blanking process because it is faster, low-cost, and requires low-energy consumption compared to other mechanical operations. This research aimed to find the effect of material thickness and type on the sheared edge characteristics of keychain cranioplasty plate using the blanking process to meet the international health standard. Experimental research conducted using an eccentric press machine with 40 tons capacity. This research’s test material parameters of titanium (Ti-6AL-4V) and stainless steel (SS-316L) were the 0.5 mm, 0.6 mm, and 0.8 mm thickness with a maximum blanking velocity of 3000 …

Effect Of Dcrp And Dcsp Polarity On The Depth Of Penetration Of Smaw On Low Carbon Steel Astm A36 Using E7018 Electrode, Ma'mun Hidayat, Helleni Febnesia, Sulaeman Deni Ramdani

Journal of Mechanical Engineering Science and Technology (JMEST)

The study aims to determine the level of penetration depth using SMAW (Shielded Metal Arc Welding) Process based on the polarity type of DCRP (Direct Current Reverse Polarity) and DCSP (Direct Current Straight Polarity). This research used ASTM A36 low carbon steel plate with thickness of 6 mm and length of 200 mm, Electrode E7018 LB-52-18 ∅ 3.2 mm, and with current parameters of 90 A, 100 A, 110 A, 120 A and 130 A and 70 ° welding arc angle. The method used the experimental research. Data collection techniques applied direct observation techniques and descriptive statistical data analysis techniques. …

Camshaft Failure Simulation With Static Structural Approach, Riduwan Prasetya, Andoko Andoko, Suprayitno Suprayitno

Journal of Mechanical Engineering Science and Technology (JMEST)

A failure happens within the camshaft of the minibus when the vehicle is in utilize. The camshaft was a fracture within the bearing between the primary cylinder exhaust valve and the second cylinder suction. This simulation aims to find the causes of camshaft failure utilizing the finite element method with a static structural approach, including simulations of deformation, strain, stress, fatigue life (stress-life and strainlife), and cracks. The method used in this paper is the finite element method with a static structural approach by ANSYS software. The camshaft material is a gray cast iron designed using Solidworks. Pre-processing includes meshing …

The Effect Of Multi-Extrusion Process Of Polylactic Acid On Tensile Strength And Fracture Morphology Of Filament Product, Muhamad Syaifuddin, Heru Suryanto, Suprayitno Suprayitno

Journal of Mechanical Engineering Science and Technology (JMEST)

Polylactic acid (PLA) is one of the most used materials in FDM 3D Printing. Large-scale consumption of PLA on an industrial scale could cause environmental and efficiency problems. Thus, PLA waste and industry waste need to be recycled to limit excessive waste. This study aimed to investigate the change in mechanical property, morphology, and structure of mechanically recycled PLA. Recycling was performed 12 times using the extrusion process with an extrusion temperature nozzle of 170°C. The SEM, structural analysis, and amorphous-crystalline analysis used XRD. The results showed a gradual decrease of tensile strength from each recycle with a total of …

Degumming Of Hemp Fibers Using Combined Microwave Energy And Deep Eutectic Solvent, Bulbul Ahmed

LSU Master's Theses

Hemp is considered as one of the sustainable agricultural fiber materials. Degumming or surface modification of hemp bast is needed to produce single fibers for ensuing textile and industrial applications. The traditional degumming process necessitates a high amount of alkali, which causes detrimental environmental pollution. This study offers a new method to degum hemp fibers with reduced use of harmful alkali and precious water resources. In this work, hemp bast fibers were degummed by using combined microwave energy and deep eutectic solvent (DES). The properties of hemp fibers manufactured by this method were investigated and compared with the traditional alkali …

Phase-Field Modeling Of The Polymer Membrane Formation Process For Micro- And Ultra-Filtration, Michael Rosario Cervellere

Graduate Theses and Dissertations

Porous polymer membrane filters are widely used in separation and filtration process. Micro- and ultra-filtration membranes are commonly used in biopharmaceutical applications such as filtering viruses and separating proteins from a carrier solution. The formation of these membrane filters via phase inversion is a complex and interconnected process where varying casting conditions can have a wide variety of effects on the final membrane morphol- ogy. Tailoring membrane filters for specific performance characteristics is a tedious and time consuming process. The time and length scales of membrane formation make it extremely difficult to experimentally observe membrane formation. Modeling the membrane formation …

Electrochemical Deposition In Energy Storage Devices, Witness Atutala Martin

Graduate Theses and Dissertations

Metals, whether in a solid or soluble ion form, are a vital part of any electrochemical storage system. More so, Li metal is widely considered as the ideal anode because of its low density and low electrochemical potential (-3.04 V vs. the standard hydrogen electrode – SHE). However, just like most metals, it does not plate or strip evenly during cycling which can lead to cycling performance issues, short cycling lifespans, and even safety concerns brought about by dendrites that can cause internal short-circuiting within cells. This research focused on investigating the electroplating of metals in both aqueous and non-aqueous …

A Computational Study Of Radiation Damage In Bilayer Silicon-Gold Structures, Cameron Hopper

Graduate Theses and Dissertations

Irradiation from sources such as nuclear reactors bombard materials with neutrons and heavy ions. The primary consequence of this irradiation is the displacement of atoms from their atomic structure. As the structure becomes damaged, the mechanical properties can change. Eventually, this can result in a failure due to embrittlement. This type of damage is hard to detect and can result in sudden, unexpected failure. Therefore, focusing on managing the consequences of irradiation has been a heavily researched topic. To manage irradiation, the focus is primarily to manage the voids and interstitials that appear during irradiation. Grain boundaries and amorphous regions …

Preparation Of Co1-XS-Mns@Cnts/Cnfs For Electrocatalytic Oxygen Reduction Reaction, Fang-Yan Liu, Qian Zhang, Yue-Kun Li, Feng Huang, Meng-Ye Wang

Journal of Electrochemistry

As an important cathode reaction in fuel cells and metal-air batteries, oxygen reduction reaction (ORR) is a complex reaction of slow kinetics, which severely limits performances of fuel cells and metal-air batteries. Therefore, it is of key importance to find an efficient and stable electrocatalyst to promote ORR. Carbon-based materials, which possess high conductivity, good stability and large specific surface area, are usually used in electrocatalytic ORR. However, pure carbon-based materials exhibit low efficiency. Coupling carbon-based materials with manganese (Mn) and cobalt (Co) transition metals containing 3d orbitals is an effective way to improve electrocatalytic performance. Herein, carbon nanofibers containing …

Synthesis And Electrochemical Study Of Cuau Nanodendrites For Co2 Reduction, Dylan Siltamaki, Shuai Chen, Farnood Rahmati, Jacek Lipkowski, Ai-Cheng Chen

Journal of Electrochemistry

The conversion of carbon dioxide (CO₂) to carbon monoxide (CO) and other value-added products is an interesting approach for carbon-containing fuel synthesis using renewable and clean energy. The electrochemical reduction of CO₂ is one of the promising strategies for the storage of intermittent renewable energy resources. The development of electrocatalysts with high activity and stability is vital in the electrochemical CO₂ reduction process. In this study, copper and gold alloyed (CuAu) electrodes with nanodendritic structures were synthesized using a facile electrodeposition method. The CuAu nanodendrites with the atomic ratio of Cu to Au being approximately 1:1 …

Progress Of Lithium-Ion Transport Mechanism In Solid-State Electrolytes, Bing-Kai Zhang, Lu-Yi Yang, Shun-Ning Li, Feng Pan

Journal of Electrochemistry

Inorganic crystalline solid electrolytes exhibit exceptional room-temperature ionic conductivities, giving them the potential to enable all-solid-state lithium (Li) - ion batteries. Developing new high-performance electrolytes is one of the most critical challenges to realize solid-state batteries, which requires understanding how chemistry facilitates fast ionic conduction and what the Li-ion migration mechanism is in inorganic solid electrolytes. In this review, we aim to summarize recent fundamental research progress in Li-ion transport, including crystal structure, behavior of ion migration (i.e., single-ion jump and multi-ions cooperative migration), and the relationship between ion migration and microstructure.
Generally, ion transport in crystalline structure can be …

Design And Fabrication Of The Electrolytic Cell With Silicon-Based Boron-Doped Diamond Electrode And Its Feasibility ForIn-Situ Nuclear Magnetic Resonance Study, Hao Peng, Hui-Jun Sun, Zhi-You Zhou, Lin-Fan Shen, Long Huang, Shuo-Hui Cao, Shi-Gang Sun

Journal of Electrochemistry

In-situ EC-NMR technique can be used to monitor the electrochemical reaction process in real-time and to explain the reaction mechanism at the molecular level, which is a promising and non-destructive online detection technology. This article for the first time reports the design and production of in-situEC-NMR three-electrode single-chamber electrolytic cell using silicon-based boron-doped diamond (Si/BDD) as the working electrode. Research shows that the geometric size of Si/BDD electrode being 12.5 mm 1.2 mm 0.5 mm in the NMR detection zone is small and the thickness of the electrode material is thin, which accounts for the less hindrance …

Recent Advances In Glycerol Electrooxidation On Pt And Pd: From Reaction Mechanisms To Catalytic Materials, Wei-Yi Zhang, Xian-Yin Ma, Shou-Zhong Zou, Wen-Bin Cai

Journal of Electrochemistry

The conversion of glycerol to value-added products has received considerable attention recently because the booming biodiesel industry produces a large amount of glycerol as a byproduct. Among various means, electrocatalytic oxidation of glycerol is appealing owing to its environmental friendliness and high efficiency. However, electrooxidation of glycerol is very complex, involving multiple electron and proton transfer processes with many reaction pathways. How to rationally design catalysts with high selectivity toward targeted products is an overarching challenge, and of both fundamental and practical significance. In this minireview we aim to provide an overview of recent advancements in electrooxidation of glycerol focusing …

Atomistic Thermo-Mechanical Description Of The Deformation Behavior, Scaling Laws, And Constitutive Modeling Of Nanoporous Gold, Mohammed Hassan Yousef Saffarini

LSU Doctoral Dissertations

Metallic foams, or nanoporous (NP) metals as it is widely referred to in literature, with ligament sizes up to a few tens of nm show exceptional mechanical properties such as high strength and stiffness per weight ratio under different loading scenarios due to their high surface area to solid volume ratio. Therefore, they can be utilized in a wide range of applications making them of great interest to researchers. While their elasticity and yield strength have been the subject of several studies, very limited attention was given to the effect of size, strain rate, and temperature on the material plastic …

Development Of A Marine Biodegradable Target Balloon, Blake Samuel Robinson, Arash Sam Akhavi, David Leonardo Albarran-Martinez

Materials Engineering

The US Navy utilizes PVC target balloons, known as Killer Tomatoes, that are inflated onboard a naval vessel then deployed into the ocean to calibrate a variety of weaponry. The Navy has requested the investigation of biodegradable polymers to replace the PVC in attempts to reduce ocean waste that is generated from the leftover PVC material. After communicating with American Pacific Plastic Fabricators (APPF), the current manufacturer of the Killer Tomatoes, we gained an understanding of the manufacturing process and the material requirements that would allow a new material to be integrated into their current process. Two proprietary, trial polymers …

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

McKelvey School of Engineering Graduate Student Theses & Dissertations

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

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

McKelvey School of Engineering Graduate Student Theses & Dissertations

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

Rational Design And Optimization Of Perovskite Semiconductors, Arashdeep Thind

McKelvey School of Engineering Graduate Student Theses & Dissertations

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

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

Plasmonically-Enhanced Ultrasensitive Biodetection Technologies, Zheyu Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

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

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

Advanced Science Research Center

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

A Hyperelastic Porous Media Framework For Ionic Polymer-Metal Composites And Characterization Of Transduction Phenomena Via Dimensional Analysis And Nonlinear Regression, Zakai J. Olsen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ionic polymer-metal composites (IPMC) are smart materials that exhibit large deformation in response to small applied voltages, and conversely generate detectable electrical signals in response to mechanical deformations. The study of IPMC materials is a rich field of research, and an interesting intersection of material science, electrochemistry, continuum mechanics, and thermodynamics. Due to their electromechanical and mechanoelectrical transduction capabilities, IPMCs find many applications in robotics, soft robotics, artificial muscles, and biomimetics. This study aims to investigate the dominating physical phenomena that underly the actuation and sensing behavior of IPMC materials. This analysis is made possible by developing a new, hyperelastic …

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

Mechanical Engineering Undergraduate Honors Theses

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

Design And Control Of A Peristaltic Pump To Simulate Left Atrial Pressure In A Conductive Silicone Model, Jeremy Collins

Mechanical Engineering Undergraduate Honors Theses

According to the CDC, atrial fibrillation is responsible for more than 454,000 hospitalizations and approximately 158,000 deaths per year. A common treatment for atrial fibrillation is catheter ablation, a process in which a long flexible tube is guided through the femoral artery and to the source of arrhythmia in the heart, where it measures the electrical potential at various locations and converts problematic heart tissue to scar tissue via ablation. This paper details the design and control of a low-cost ($400) peristaltic pump system using repetitive control to replicate blood pressure in the left atrium in a conductive silicone model …

Study Of Static And Dynamical Properties Of Complex Antiferroelectrics Materials, Kinnary Yogeshbhai Patel

Graduate Theses and Dissertations

The aim of this dissertation is the investigation of the static and dynamical properties of the complex antiferroelectric materials using Effective Hamiltonian method and First principles calculations. In chapter 3, a novel elemental interatomic coupling in perovskite materials which bilinearly couples the antiferroelectric displacements of cations with the rotations of the oxygen octahedra. This new coupling explains a very complex crystal structure of prototypical antiferroelectric PbZrO3. My explanation provides a unified description of many other complex antipolar crystal structures in variety of perovskite materials, including the occurrence of incommensurate phases in some of them. In chapter 4, results and analysis …

Application Of Atomically Precise Metal Nanoclusters In Electrocatalysis, Zhi-Hua Zhuang, Wei Chen

Journal of Electrochemistry

Metal nanoclusters (M NCs) consist of only several to a few hundred of metal atoms and possess core sizes less than 2 nm. Owing to the quantum size effect, the electronic states of M NCs evolve to discrete levels similar to the molecule energy gaps, other than a continuous density of states to produce plasmon characteristic of bulk metal nanoparticles (M NPs). In comparison with the conventional M NPs, M NCs exhibit dramatically unique electronic and optical properties, such as molecule-like energy gaps, strong photoluminescence and high catalytic properties, which make them promising for potential application in numerous fields, such …

Electrochemiluminescence Imaging Hydrogen Evolution Reaction On Single Platinum Nanoparticles Using A Bipolar Nanoelectrode Array, Xiang Qin, Zhong-Qiu Li, Jian-Bin Pan, Jian Li, Kang Wang, Xing-Hua Xia

Journal of Electrochemistry

A high-density (5.7 × 10⁸ cm^-2) nanoelectrode array with the electrode diameter of 200 nm and the interelectrode distance of 450 nm were fabricated. The nanoelectrode array consisted of gold nanowires embedded in a porous anodic aluminum oxide (AAO) matrix, having regular nanoelectrode distribution and highly uniform nanoelectrode size. The gold nanoelectrode array was used as a closed bipolar nanoelectrode array combined with electrochemiluminescence (ECL) method to map the electrocatalytic activity of platinum nanoparticles toward hydrogen evolution reaction (HER) by modifying the catalysts on single nanoelectrodes. Results show that HER on single bipolar nanoelectrodes could be imaged …

Oxygen-Exposure Induced Rapid Oxidation Of Spiro-Ometad In Cspbibr2 Perovskite Solar Cells, Wei-Guo Wang, Tian Bai, Gao-Fei Xue, Mei-Dan Ye

Journal of Electrochemistry

2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (Spiro-OMeTAD) is the most widely used hole transport material in perovskite solar cells (PSCs). However, its oxidation in the air takes a long time and results in the attack of perovskite by water. In this regard, we performed the oxidation process of Spiro-OMeTAD in oxygen, where perovskite can be protected from water, guaranteeing the integrity of perovskite. It was demonstrated that the champion Spiro-OMeTAD based CsPbIBr₂ PSCs after oxygen oxidation achieved a 7.19% power conversion efficiency (PCE), showing a higher PCE than 6.29% of the champion device oxidized in air. A series of electrochemical characterization methods were applied …

Theoretical Studies Of Metal-N-C For Oxygen Reduction And Hydrogen Evolution Reactions In Acid And Alkaline Solutions, Xue-Ping Qin, Shang-Qian Zhu, Lu-Lu Zhang, Shu-Hui Sun, Min-Hua Shao

Journal of Electrochemistry

Single atom catalysts (SAC) have been regarded as the promising alternatives to platinum group metals due to their low costs and potentially high catalytic activities in various electrocatalytic reactions. The atomic mechanism understanding of activity discrepancy among different metal and nitrogen co-doped carbon-based catalysts is still lacking. Here, non-precious metal and nitrogen co-doped carbons (Me-N-C, Me = Fe and Co) as the model catalysts are investigated by combining experimental and theoretical studies to explore the catalytic activities and corresponding reaction mechanisms toward oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) at universal pHs. Atomic theoretical simulations suggest that Fe-N-C …

Lithium Storage Performance Of Hard Carbons Anode Materials Prepared By Different Precursors, Zhen-Lang Liang, Yao Yang, Hao Li, Li-Ying Liu, Zhi-Cong Shi

Journal of Electrochemistry

Hard carbon is one of the most promising anode material for lithium ion batteries (LIBs) owing to its high stability, widespread availability, low-cost, and excellent performance. The electrochemical properties of hard carbon materials depend strongly on the type of precursors. It is, therefore, very important to choose an excellent hard carbon precursor. Polyacrylonitrile, petroleum pitch and peanut shells were used as raw materials to prepare different hard carbon anode materials for LIBs. These hard carbon anode materials were successfully synthesized in two steps. The selected precursor was firstly carbonized at 600℃ for 1 h in argon atmosphere using heating rate …

Pd-Based Electrocatalysts For Oxygen Reduction And Ethanol Oxidation Reactions: Some Recent Insights Into Structures And Mechanisms, Zhi-Peng Wu, Chuan-Jian Zhong

Journal of Electrochemistry

The development of efficient electrocatalysts for applications in fuel cells, including proton-exchange membrane fuel cell (PEMFC) and direct ethanol fuel cell (DEFC), has attracted extensive research attention in recent years. Oxygen reduction reaction and ethanol oxidation reaction are two of the key reactions where the design of active, stable and low-cost electrocatalysts is critical for the mass commercializations of PEMFCs and DEFCs. This challenge stems largely from the limited understanding of the catalyst structures and reaction mechanisms. Progress has been made in investigations of electrocatalysts derived from Pd-based alloy nanomaterials both experimentally and computationally. We highlight herein some of the …