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Full-Text Articles in Engineering Science and Materials

Graphene Twistronics: Tuning The Absorption Spectrum And Achieving Metamaterial Properties, Ammar Armghan, Meshari Alsharari, Khaled Aliqab, Osamah Alsalman, Juveriya Parmar, Shobhit K. Patel Mar 2023

Graphene Twistronics: Tuning The Absorption Spectrum And Achieving Metamaterial Properties, Ammar Armghan, Meshari Alsharari, Khaled Aliqab, Osamah Alsalman, Juveriya Parmar, Shobhit K. Patel

Department of Mechanical and Materials Engineering: Faculty Publications

Graphene twistronics using multilayer graphene is presented in such a way that it provides a metamaterial effect. This manuscript also analyzes the prediction of behavior using machine learning. The metamaterial effect is achieved by twisting the graphene layers. Graphene twistronics is a new concept for changing the electrical and optical properties of bilayer graphene by applying a small angle twist between the layers. The angle twists of 5o, 10o, and 15o are analyzed for the proposed graphene twistronics design. Tuning in the absorption spectrum is achieved by applying small twists to the angles of the …


Sars-Cov-2 Detecting Rapid Metasurface-Based Sensor, Shobhit K. Patel, Jaymit Surve, Juveriya Parmar, Khaled Aliqab, Meshari Alsharari, Ammar Armghan Dec 2022

Sars-Cov-2 Detecting Rapid Metasurface-Based Sensor, Shobhit K. Patel, Jaymit Surve, Juveriya Parmar, Khaled Aliqab, Meshari Alsharari, Ammar Armghan

Department of Mechanical and Materials Engineering: Faculty Publications

We have proposed a novel approach to detect COVID-19 by detecting the ethyl butanoate which high volume ratio is present in the exhaled breath of a COVID-19 infected person. We have employed a refractive index sensor (RIS) with the help of a metasurface-based slotted T-shape perfect absorber that can detect ethyl butanoate present in exhaled breath of COVID-19 infected person with high sensitivity and in-process SARS-CoV-2. The optimized structure of the sensor is obtained by varying several structure parameters including structure length and thickness, slotted T-shape resonator length, width, and thickness. Sensor’s performance is evaluated based on numerous factors comprising …


Synthesis Of Graphene And Graphene-Based Composite Membrane, Yuanjun Fan Nov 2017

Synthesis Of Graphene And Graphene-Based Composite Membrane, Yuanjun Fan

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

Vibration membrane equipped for earphone requires high performance in both mechanical properties and electronic properties. With extraordinary properties on both, graphene and graphene-based composite materials appear as a promising candidate for this application. Chemical vapor deposition (CVD) is believed to be the most convenient way to synthesize a large area (on scale of square centimeters) as well as a homogeneous thickness for the membrane. The thesis focuses on applying control variable experiment method to analyze different effects on mechanical property of the two CVD setting parameters: cooling rate, and hydrocarbon precursor. For isolating the specimens efficiently, a modified electrochemical method …


Suspended Graphene-Based Gas Sensor With 1-Mw Energy Consumption, Jong-Hyun Kim, Qin Zhou, Jiyoung Chang Jan 2017

Suspended Graphene-Based Gas Sensor With 1-Mw Energy Consumption, Jong-Hyun Kim, Qin Zhou, Jiyoung Chang

Department of Mechanical and Materials Engineering: Faculty Publications

This paper presents NH3 sensing with ultra-low energy consumption for fast recovery and a graphene sheet based on a suspended microheater. Sensitivity and repeatability are important characteristics of functional gas sensors embedded in mobile devices. Moreover, low energy consumption is an essential requirement in flexible and stretchable mobile electronics due to their small dimension and fluctuating resistivity during mechanical behavior. In this paper, we introduce a graphene-based ultra-low power gas detection device with integration of a suspended silicon heater. Dramatic power reduction is enabled by a duty cycle while not sacrificing sensitivity. The new oscillation method of heating improves …


Microstructure And Mechanical Properties Of Nanofiller Reinforced Tantalum-Niobium Carbide Formed By Spark Plasma Sintering, Christopher Charles Rudolf May 2016

Microstructure And Mechanical Properties Of Nanofiller Reinforced Tantalum-Niobium Carbide Formed By Spark Plasma Sintering, Christopher Charles Rudolf

FIU Electronic Theses and Dissertations

Ultra high temperature ceramics (UHTC) are candidate materials for high temperature applications such as leading edges for hypersonic flight vehicles, thermal protection systems for spacecraft, and rocket nozzle throat inserts due to their extremely high melting points. Tantalum and Niobium Carbide (TaC and NbC), with melting points of 3950°C and 3600°C, respectively, have high resistivity to chemical attack, making them ideal candidates for the harsh environments UHTCs are to be used in. The major setbacks to the implementation of UHTC materials for these applications are the difficulty in consolidating to full density as well as their low fracture toughness. In …


Electrochemical H2O2Sensor Based On The Co-Immobilization Of Phosphmolybdic Acid And Graphene On Pedot Film Electrode With Nafion, Hao-Xian Zhou, Jun-Ming Zhang, Zhi-Yu Qu, Pan-Yu Zhang, You-Jun Fan Feb 2016

Electrochemical H2O2Sensor Based On The Co-Immobilization Of Phosphmolybdic Acid And Graphene On Pedot Film Electrode With Nafion, Hao-Xian Zhou, Jun-Ming Zhang, Zhi-Yu Qu, Pan-Yu Zhang, You-Jun Fan

Journal of Electrochemistry

With a glassy carbon electrode (GCE) as the substrate, the poly(3,4-ethylenedioxythiophene) (PEDOT) film electrode was prepared through the electrochemical polymerization method, then a novel non-enzymatic electrochemical H2O2 sensor was fabricated by co-immobilizing phosphomolybdic acid and graphene with Nafion on the PEDOT/GCE electrode. The modified electrodes were characterized by scanning electron microscopy (SEM), while the responsive properties of the sensor to H2O2 were investigated by cyclic voltammetry and chronoamperometry. The results demonstrated that, under the optimized conditions, the sensor exhibited good electrocatalytic performance for H2O2 reduction. The current response of the sensor …


Liquid-Phase Exfoliation Of Two-Dimensional Graphite For Ink-Jet Printing, Monica Michel Jan 2016

Liquid-Phase Exfoliation Of Two-Dimensional Graphite For Ink-Jet Printing, Monica Michel

Open Access Theses & Dissertations

Over the last decade, the study of two-dimensional (2D) materials has seen an incredible growth due to their unique thermal, mechanical and electronic properties. Solution phase manufacturing offers a way in which they can be produced at large scale by creating dispersions from the exfoliated material. Once created, different options for assembling devices exist. One technique for large scale manufacturing of materials in this form is ink-jet printing, which is a form of additive manufacturing that has proven to be attractive for the printed electronics industry. One challenge that ink-jet printing still faces is the shortage of inks with appropriate …


Boosting Electrocatalytic Activity Of Nitrogen-Doped Graphene/Carbon Nanotube Composite For Oxygen Reduction Reaction, Yu Zhang, Jin-Song Hu, Wen-Jie Jiang, Lin Guo, Zi-Dong Wei, Li-Jun Wan Oct 2014

Boosting Electrocatalytic Activity Of Nitrogen-Doped Graphene/Carbon Nanotube Composite For Oxygen Reduction Reaction, Yu Zhang, Jin-Song Hu, Wen-Jie Jiang, Lin Guo, Zi-Dong Wei, Li-Jun Wan

Journal of Electrochemistry

Developing low-cost catalysts with high electrocatalytic activity for oxygen reduction reaction (ORR) has recently attracted much attention because the sluggish ORR currently limits the performance and commercialization of fuel cells and metal-air batteries as well. Nitrogen doped carbon materials have been considered as a promising candidate for the replacement of high-cost and scarce Pt-based catalysts although their electrocatalytic activity still needs to be much improved. In this work, an improved nitrogen-doped graphene/carbon nanotubes composite (N-rGO/CNT) was developed as an efficient ORR electrocatalyst. It was found that the ORR activity of N-rGO/CNT composite could be significantly enhanced by introducing iron in …


Preparation And Electrochemical Performance Of Tio2/Gns Nanocomposite As Anode Materials For Lithium-Ion Batteries, Lin-Lin Qin, Huan Zhang, Xiao-Jing Liu, Jian-Hui Xu, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong Jun 2012

Preparation And Electrochemical Performance Of Tio2/Gns Nanocomposite As Anode Materials For Lithium-Ion Batteries, Lin-Lin Qin, Huan Zhang, Xiao-Jing Liu, Jian-Hui Xu, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The honeycomb-like porous TiO2/graphenes (TiO2/GNs) nanocomposite was prepared by a reflux method. SEM and TEM results showed that nanosized anatase TiO2 (about 5~10 nm) were dispersed uniformly on the surface of the GNs. The TiO2/GNs composite showed excellent rate and cycling performance: A stable charge capacity of 169.5 mAh?g-1 was obtained at 30C, and can restore to 241.7 mAh?g-1 while current went back to 1C. The stable charge capacity of TiO2/GNs nanocomposite electrode up to 201.9 mAh?g-1 was achieved at 10C in the first cycle, and could be maintained at 181.4 mAh?g-1 after 300 times of cycling.


Development Of Nanocomposites For Energy Storage Devices, Md Ashiqur Rahaman Khan Jan 2012

Development Of Nanocomposites For Energy Storage Devices, Md Ashiqur Rahaman Khan

Open Access Theses & Dissertations

With the ever-increasing need in improving the performance and operation life of future mobile devices, developing higher power density energy storage devices has been receiving more attention. Lithium ion battery (LIB) and capacitor are two of the most widely used energy storage devices and have attracted increasing interest from both industrial and academic fields. Batteries have higher power density than capacitor but significantly longer charge/discharge rates. In order to further improve the performance of these energy storage devices, one of the approaches is to use high specific surface area nano-materials. Among all the nano-materials developed so far, one-dimensional nanowires are …


Identification Of Multiple Oscillation States Of Carbon Nanotube Tipped Cantilevers Interacting With Surfaces In Dynamic Atomic Force Microscopy, Mark Strus, Arvind Raman Jan 2009

Identification Of Multiple Oscillation States Of Carbon Nanotube Tipped Cantilevers Interacting With Surfaces In Dynamic Atomic Force Microscopy, Mark Strus, Arvind Raman

Birck and NCN Publications

Carbon nanotubes (CNTs) have gained increased interest in dynamic atomic force microscopy (dAFM) as sharp, flexible, conducting, nonreactive tips for high-resolution imaging, oxidation lithography, and electrostatic force microscopy. By means of theory and experiments we lay out a map of several distinct tapping mode AFM oscillation states for CNT tipped AFM cantilevers: namely, noncontact attractive regime oscillation, intermittent contact with CNT slipping or pinning, or permanent contact with the CNT in point or line contact with the surface while the cantilever oscillates with large amplitude. Each state represents fundamentally different origins of CNT-surface interactions, CNT tip-substrate dissipation, and phase contrast …