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Articles 1 - 11 of 11
Full-Text Articles in Mechanical Engineering
Atomic Force Microscopy Based Dna Sensing And Manipulation, Matthew Shubert
Atomic Force Microscopy Based Dna Sensing And Manipulation, Matthew Shubert
Mechanical Engineering Undergraduate Honors Theses
Sequencing DNA provides a positive impact for the biomedical community by understanding a wide variety of applications such as human genetics, disease, and pathogens. The reason the Arkansas Micro & Nano Systems lab is involved with research in DNA sequencing is due to the current, leading industry method. Nanopore sequencing was developed by Oxford Nanopore Technology in which its sequencing method separates double stranded DNA to electrically characterize individual nucleotides traveling through a charged nanopore. Unfortunately, nanopore sequencing uses biological materials that require a shelf life and drives high cost. Therefore, the Arkansas Micro & Nano Systems lab has developed …
Designing Cryogenic Strain Device For 2d Materials, Jake Carter
Designing Cryogenic Strain Device For 2d Materials, Jake Carter
Mechanical Engineering Undergraduate Honors Theses
The Churchill lab working within the Physics Department at the University of Arkansas is working to create important quantum states including weak topological insulators (TIs) through the use of symmetry engineering and topological electronic states in two-dimensional (2D) crystals of WHM materials. Experimental results of these topological states have been obstructed due to the difficulty to perform controlled in situ strain. This project strives to create a mount to utilize a piezoelectric nanopositioner within cryostats achieving an in situ strain that creates the quantum states the lab is looking to observe. This report also examines the necessary equations to determine …
Nanoscratch Study Of Diamond-Like Carbon Coatings With A Polydopamine + Sio2 Adhesive Underlayer, Anna Fisher
Nanoscratch Study Of Diamond-Like Carbon Coatings With A Polydopamine + Sio2 Adhesive Underlayer, Anna Fisher
Mechanical Engineering Undergraduate Honors Theses
Diamond-like carbon (DLC) coatings have a wide array of desirable characteristics such as low friction, high hardness, and scratch resistance. Due to high residual stress and thermal mismatch, DLC films experience adhesion difficulties when bonded with metallic substrates, leading to cracking and delamination. In this study, the properties of a new coating with a polydopamine underlayer and silica nanoparticles bonded to a stainless-steel substrate (PDA+SiO2/DLC) were studied alongside three other samples, one with a polydopamine underlayer (PDA/DLC), one with a trimethylsilane (TMS) underlayer (TMS/DLC), and one with no underlayer (DLC only). Nanoscratch tests were performed with a 1 μm spheroconical …
Ultrasonic Wave Propagation In Copper/Graphene Metal Matrix Composites, Casey Lindbloom
Ultrasonic Wave Propagation In Copper/Graphene Metal Matrix Composites, Casey Lindbloom
Mechanical Engineering Undergraduate Honors Theses
Emerging metallic composite materials implanted with graphene sheets are showing immense promise, with benefits being observed with regards to mechanical, thermal, and electrical material properties. This research aims to investigate the effects on ultrasonic wave propagation in Copper/Graphene Metal Matrix Composites (Cu/Gr MMCs) with varying graphene arrangements inspired from nacre and bone nanoscale material distributions. To accomplish this, the molecular dynamics (MD) method is utilized to simulate nanoscale wave propagation on a set of Cu/Gr MMCs with differing graphene arrangements and volume percentages ranging up to 4.56%. The computational model results are then analyzed to determine the variation in energy …
Modelling Palladium Decorated Graphene Using Density Functional Theory To Analyze Hydrogen Sensing Application, Sameer Kulkarni
Modelling Palladium Decorated Graphene Using Density Functional Theory To Analyze Hydrogen Sensing Application, Sameer Kulkarni
Mechanical Engineering Undergraduate Honors Theses
Graphene is an exciting new material with many promising applications. One such application of graphene is gas sensing, when adsorbed with transition metals, notably Palladium. Therefore, it is of paramount importance to have appropriate ab initio calculations to calculate the various properties of graphene under different adsorbates and gasses. The first step in these calculations is to have a functioning base Density Functional Theory (DFT) model of pristine graphene decorated with Palladium. The computational methods described in this paper has yielded results for pristine graphene that have been confirmed many times in previous experimental and theoretical studies. Future work needs …
A Nanoindentation Study Of The Fatigue Properties Of Al/A-Si Core-Shell Nanostructures, Jason Steck
A Nanoindentation Study Of The Fatigue Properties Of Al/A-Si Core-Shell Nanostructures, Jason Steck
Mechanical Engineering Undergraduate Honors Theses
Nanostructure-textured surfaces can reduce friction and increase the reliability of micro- and nanoelectromechanical systems (NEMS/MEMS). For MEMS incorporating moving parts, the fatigue properties of nanostructures pose a challenge to their reliability in long-term applications. In this study, the fatigue behavior of hemispherical Al/a-Si core-shell nanostructures (CSNs), bare hemispherical Al nanodots, and a flat Al/a-Si layered thin film have been studied using nanoindentation and nano-scale dynamic mechanical analysis (nano-DMA) techniques. Fatigue testing with nano-DMA shows that the deformation resistance of CSNs persists through 5.0 × 104 loading cycles at estimated contact pressures greater than 15 GPa. When the a-Si shell …
Non-Covalent Functionalization Of Graphene Films For Uniform Nanoparticle Deposition Via Atoic Layer Deposition, Ty Seiwert
Mechanical Engineering Undergraduate Honors Theses
Graphene functionalized with platinum (Pt) and palladium (Pd) has proven to be highly effective as a hydrogen sensor. Deposition methods such as Atomic layer deposition (ALD) can be further enhanced by pretreating the graphene with a non-covalent surfactant prior to nanoparticle deposition. In this study, graphene-based sensing devices will be fabricated by ALD deposition. The graphene will be non-covalently functionalized using sodium dodecyl sulfate (SDS) anionic surfactant prior to ALD deposition. The aim of this study is to test the deposition pattern achieved by varying the amount of time that graphene is treated with the SDS surfactant. Initially, ALD deposition …
Optimization Of Reduced Graphene Oxide Deposition For Hydrogen Sensing Technologies, Matthew Pocta
Optimization Of Reduced Graphene Oxide Deposition For Hydrogen Sensing Technologies, Matthew Pocta
Mechanical Engineering Undergraduate Honors Theses
Graphene is known to be a key material for improving the performance of hydrogen sensors. High electrical conductivity, maximum possible surface area with respect to volume, and high carrier mobility are a few of the properties that make graphene ideal for hydrogen sensing applications. The problem with utilizing graphene is the difficulty in depositing uniform, thin layers onto substrate surfaces. This study examines a new method of optimizing graphene deposition by utilizing an airbrush to deposit both graphene oxide (GO) and reduced graphene oxide (rGO) onto glass substrates. The number of depositions were varied among samples to study the effect …
Optical Analysis And Fabrication Of Micro And Nanoscale Plasmonically Enhanced Devices, Avery M. Hill
Optical Analysis And Fabrication Of Micro And Nanoscale Plasmonically Enhanced Devices, Avery M. Hill
Mechanical Engineering Undergraduate Honors Theses
Plasmonic nanostructures have been shown to act as optical antennas that enhance optical devices due to their ability to focus light below the diffraction limit of light and enhance the intensity of the incident light. This study focuses on computational electromagnetic (CEM) analysis of two devices: 1) GaAs photodetectors with Au interdigital electrodes and 2) Au thin-film microstructures. Experiments showed that the photoresponse of the interdigital photodetectors depend greatly on the electrode gap and the polarization of the incident light. Smaller electrode gap and transverse polarization give rise to a larger photoresponse. It was also shown that the response from …
Atomic Force Microscopy Based Dna Analysis, Drew Creighton
Atomic Force Microscopy Based Dna Analysis, Drew Creighton
Mechanical Engineering Undergraduate Honors Theses
This report explores dry and wet scanning of a surface and DNA pickup using an AFM, as well as fluorescent staining of DNA. Dry and wet scans of DNA were obtained using a cantilever AFM tip in tapping mode. Dry scans were found to be clearer than wet scans; however, the drying process was found to decrease the thickness of DNA 2–4 times less than its original thickness. Alternately, wet scans were found to be less clear than dry scans and introduced more noise into the images obtained. Additionally, DNA kept its initial thickness during wet scanning. DNA was capable …
Atomic Force Microscope Imaging Of Dna And Multi Walled Carbon Nanotubes, Jacob Hohnbaum
Atomic Force Microscope Imaging Of Dna And Multi Walled Carbon Nanotubes, Jacob Hohnbaum
Mechanical Engineering Undergraduate Honors Theses
The Micro and Nano System Laboratory at the University of Arkansas currently is equipped with an Atomic Force Microscope (AFM). This device can be used to measure objects with resolution on the nanometer scale, but there are a number of technical difficulties in performing scans of carbon nanotubes and DNA. The goal of this research is to successfully perform scans on both carbon nanotubes and DNA and to also establish laboratory processing protocols to re-perform such scans in the future. Previous works performed by other researchers in the laboratory provided basic protocols with which to begin the present research. These …