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Graphene

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Full-Text Articles in Engineering

Effects Of Polymer Side-Group Size On Interfacial Mechanics Of Graphene-Polymer Nanocomposites, Grace Brokaw Dec 2022

Effects Of Polymer Side-Group Size On Interfacial Mechanics Of Graphene-Polymer Nanocomposites, Grace Brokaw

All Theses

Graphene-reinforced polymer nanocomposites possess excellent mechanical, thermal, and electrical properties, which make them promising candidates for various applications. Favorable interfacial interactions and mechanics between graphene sheets and polymer matrices are often essential to achieve superior mechanical properties. Nevertheless, it remains largely elusive how molecular features of polymer systems, particularly the side-group size of polymer chains, affect the interfacial mechanics between graphene sheets and polymer matrices, primarily due to challenges in well controlling these features in experiments. On the other hand, exploring their roles in the mechanical properties of graphene-polymer nanocomposites is very expensive to study with all-atomistic molecular dynamics (MD) …


Role Of Nanoparticles In Achieving Macroscale Superlubricity Of Graphene/Nano-Sio2 Particle Composites, Panpan Li, Li Ji, Hongxuan Li, Lei Chen, Xiaohong Liu, Huidi Zhou, Jianmin Chen Sep 2022

Role Of Nanoparticles In Achieving Macroscale Superlubricity Of Graphene/Nano-Sio2 Particle Composites, Panpan Li, Li Ji, Hongxuan Li, Lei Chen, Xiaohong Liu, Huidi Zhou, Jianmin Chen

Friction

Recent studies have reported that adding nanoparticles to graphene enables macroscale superlubricity to be achieved. This study focuses on the role of nanoparticles in achieving superlubricity. First, because graphene nanoscrolls can be formed with nanoparticles as seeds under shear force, the applied load (or shear force) is adjusted to manipulate the formation of graphene nanoscrolls and to reveal the relationship between graphene-nanoscroll formation and superlubricating performance. Second, the load-carrying role of spherical nano-SiO2 particles during the friction process is verified by comparison with an elaborately designed fullerene that possesses a hollow-structured graphene nanoscroll. Results indicate that the incorporated nano-SiO …


Fabrication And Non-Covalent Functionalization And Characterization Of Graphene-Based Devices On Novel Substrate Cadmium Trithiophosphate (Iv) — Cdps, Abayomi Omotola Omolewu Aug 2022

Fabrication And Non-Covalent Functionalization And Characterization Of Graphene-Based Devices On Novel Substrate Cadmium Trithiophosphate (Iv) — Cdps, Abayomi Omotola Omolewu

Graduate Theses and Dissertations

With graphene at the center of several application areas such as sensing, circuits, high-frequency devices for communication systems, etc., it is crucial to understand how the intrinsic properties of devices made from graphene and other materials like platinum and palladium nanoparticles affect the performance of such devices for the specific application area. Many graphene-based devices for different application areas have focused mainly on the material composition of the graphene-based devices and how it affects performance parameters for the specific application. However, it would be insightful to understand how the intrinsic electrical properties of the graphene devices for different applications affect …


Nonreciprocal Electromagnetics Of Layered Media, Samaneh Pakniyat Aug 2022

Nonreciprocal Electromagnetics Of Layered Media, Samaneh Pakniyat

Theses and Dissertations

In plasmonic systems, interaction of light and surface plasmons leads to excitation of surface plasmon polaritons (SPPs) carrying energy on the surface. In an isotropic plasmonic system, the SPPs optical response is reciprocal, which means that the forward and backward surface waves have identical propagation behaviors and SPPs refract when they encounter a discontinuity on the surface. In order to excite SPPs resilient to the surface disorders, the system reciprocity needs to be broken by different techniques such as applying an external magnetic bias. In this case, the plasmonic system becomes a gyrotropic medium. Recently, it has been shown that …


Enhanced Tribological Properties Of Aligned Graphene-Epoxy Composites, Yuefeng Du, Zhenyu Zhang, Dong Wang, Lezhen Zhang, Junfeng Cui, Yapeng Chen, Mingliang Wu, Ruiyang Kang, Yunxiang Lu, Jinhong Yu, Nan Jiang Jun 2022

Enhanced Tribological Properties Of Aligned Graphene-Epoxy Composites, Yuefeng Du, Zhenyu Zhang, Dong Wang, Lezhen Zhang, Junfeng Cui, Yapeng Chen, Mingliang Wu, Ruiyang Kang, Yunxiang Lu, Jinhong Yu, Nan Jiang

Friction

The random distribution of graphene in epoxy matrix hinders the further applications of graphene-epoxy composites in the field of tribology. Hence, in order to fully utilize the anisotropic properties of graphene, highly aligned graphene-epoxy composites (AGEC) with horizontally oriented structure have been fabricated via an improved vacuum filtration freeze-drying method. The frictional tests results indicated that the wear rate of AGEC slowly increased from 5.19×10-6 mm3/(N·m) to 2.87×10-5 mm3/(N·m) with the increasing of the normal load from 2 to 10 N, whereas the friction coefficient (COF) remained a constant of 0.109. Compared to the …


Designing & Building A Microwave Plasma Reactor For Graphene Synthesis, Aviv Zohman, Jerry Larue May 2022

Designing & Building A Microwave Plasma Reactor For Graphene Synthesis, Aviv Zohman, Jerry Larue

Student Scholar Symposium Abstracts and Posters

Graphene’s remarkable electrical, optical, and chemical properties make it a promising successor to indium tin oxide for applications in flexible, transparent electronics. However, efforts to manufacture graphene have been hindered by inefficient synthesis and transfer methods. Chemical vapor deposition (CVD) is commonly used to produce graphene. CVD starts with a blank surface onto which a chemical vapor is deposited to create a single graphene layer. CVD requires extreme temperatures, so only substrates with high melting points are applicable, like metals. This excludes insulative substrates such as polymers which are essential to transparent and flexible devices. Therefore, a subsequent process transfers …


Design, Fabrication, And Characterization Of An Array Of Graphene Based Variable Capacitors, Millicent Nkirote Gikunda May 2022

Design, Fabrication, And Characterization Of An Array Of Graphene Based Variable Capacitors, Millicent Nkirote Gikunda

Graduate Theses and Dissertations

Since it was first isolated and characterized in 2004, graphene has shown the potential for a technological revolution. This is due to its amazing physical properties such as high electrical conductivity, high thermal conductivity, and extreme flexibility. Freestanding graphene membranes naturally possesses an intrinsic rippled structure, and these ripples are in constant random motion even room temperatures. Occasionally, the ripples undergo spontaneous buckling (change of curvature from concave to convex and vice versa) and the potential energy associated with this is a double well potential. This movement of graphene is a potential source of vibrational energy.

In this dissertation, we …


Near-Field Thermal Radiation In Graphene-Based Systems, Hua Lin May 2022

Near-Field Thermal Radiation In Graphene-Based Systems, Hua Lin

Honors College

Radiative heat transfer between two media separated by a sub-wavelength distance (the dominant wavelength of thermal radiation at room temperature is around 10 m.) is referred to as near-field radiative heat transfer (NFRHT). Graphene was found to have one of the greatest levels of NFRHT [1]. Additionally, NFRHT of graphene can be modulated externally via application of a bias voltage to the material [1][2], thereby altering its Fermi energy level. As such, graphene is an ideal candidate for several applications such as NFRHT for thermal switching, nano-gap thermophotovoltaic waste heat recovery, and thermal rectification. Modulation ratios as large as 77.7274 …


Combinatorial Cuni Alloy Thin Film Catalysts For Layer Number Regulation In Cvd Grown Graphene, Sumeer Khanna May 2022

Combinatorial Cuni Alloy Thin Film Catalysts For Layer Number Regulation In Cvd Grown Graphene, Sumeer Khanna

Masters Theses

In this work, synthesis of combinatorial library of CuxNi1-x (copper nickel) alloy thin films via co-sputtering from Cu (copper) and Ni (nickel) targets as catalysts for chemical vapor deposition (CVD) growth of graphene is reported. The gradient alloy morphology, composition and microstructure were characterized via scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD), respectively. Subsequently, the CuxNi1-x alloy thin films were used to grow graphene in a CH4-Ar-H2 (methane-argon-hydrogen) ambient in thermal CVD tube furnace. The underlying rationale is to adjust the CuxNi1-x …


Origin Of Friction Hysteresis On Monolayer Graphene, Deliang Zhang, Yuge Zhang, Qiang Li, Mingdong Dong Apr 2022

Origin Of Friction Hysteresis On Monolayer Graphene, Deliang Zhang, Yuge Zhang, Qiang Li, Mingdong Dong

Friction

Load-dependent friction hysteresis is an intriguing phenomenon that occurs in many materials, where the friction measured during unloading is larger than that measured during loading for a given normal load. However, the mechanism underlying this behavior is still not well understood. In this work, temperature- controlled friction force microscopy was utilized to explore the origin of friction hysteresis on exfoliated monolayer graphene. The experimental observations show that environmental adsorbates from ambient air play an important role in the load dependence of friction. Specifically, the existence of environmental adsorbates between the tip and graphene surface gives rise to an enhanced tip-graphene …


Atomistic-Continuum Membrane And Machine Learning Models For Two-Dimensional Materials, Upenda Yadav Jan 2022

Atomistic-Continuum Membrane And Machine Learning Models For Two-Dimensional Materials, Upenda Yadav

Dissertations, Master's Theses and Master's Reports

“What could we do with layered structures with just the right layers?” asked Richard Feynman in his famous 1959 lecture, “There’s plenty of room at the bottom.” With the help of the amazing developments of the past several years, we are coming close to answering that question. In 2004, graphene was first isolated from graphite and only six short years later it won the Nobel Prize in Physics. Graphene is one atomic layer of Carbon, it is the thinnest and yet the strongest materials we have ever seen. It is 200 times stronger than its equivalent weight in steel and …


Electro-Chemo-Mechanics Of The Interfaces In 2d-3d Heterostructure Electrodes, Vidushi Sharma Dec 2021

Electro-Chemo-Mechanics Of The Interfaces In 2d-3d Heterostructure Electrodes, Vidushi Sharma

Dissertations

Unique heterostructure electrodes comprising two-dimensional (2D) materials and bulk three dimensional (3D) high-performance active electrodes are recently synthesized and experimentally tested for their electrochemical performance in metal-ion batteries. Such electrodes exhibit long cycle life while they also retain high-capacity inherent to the active electrode. The role of 2D material is to provide a supportive mesh that allows buffer space for volume expansions upon ion intercalation in the active material and establishes a continuous electronic contact. Therefore, the binding strength between both materials is crucial for the success of such electrodes. Furthermore, battery cycles may bring about phase transformations in the …


Improvement Of The Lubrication Properties Of Grease With Mn, Bao Jin, Guangyan Chen, Jun Zhao, Yongyong He, Yiyao Huang, Jianbin Luo Dec 2021

Improvement Of The Lubrication Properties Of Grease With Mn, Bao Jin, Guangyan Chen, Jun Zhao, Yongyong He, Yiyao Huang, Jianbin Luo

Friction

Although grease can effectively lubricate machines, lubrication failure may occur under high speed and heavy load conditions. In this study, Mn3O4/graphene nanocomposites (Mn3O4#G) were synthetized using a hydrothermal method as lubricant additives. The lubrication properties of compound grease with Mn3O4#G nanocomposite additive under heavy contact loads of 600-900 N (3.95-4.59 GPa) were investigated. First, the nanocomposites were dispersed into L-XBCEA 0 lithium grease via successive electromagnetic stirring, ultrasound vibration, and three-roll milling. Compound grease with additives of commercial graphene (Com#G) was also investigated for comparison. Tribological test results …


Biosensor Devices Based On Graphene And 2d Materials, Suhada Poovathy Nov 2021

Biosensor Devices Based On Graphene And 2d Materials, Suhada Poovathy

Theses

Nanomaterials offered new improvements and developments to the bio-sensing field due to their unique physical and chemical properties. Unique and exceptional electronic properties, such as the ultrahigh surface-to-volume ratio and the excellent electrical properties of the 2D materials like in graphene, making these materials promising for future smaller and faster electronics, but an extensive amount of research is still needed. This thesis is concerned with the study of the integration of 2D material graphene in the development of sensitive and rapid biosensors. The main objective of this thesis is to understand the features and characteristics of graphene, evaluate the scope …


Laser-Defined Graphene Strain Sensor Directly Fabricated On 3d-Printed Structure, Tyler M. Webb, Twinkle Pandhi, David Estrada Sep 2021

Laser-Defined Graphene Strain Sensor Directly Fabricated On 3d-Printed Structure, Tyler M. Webb, Twinkle Pandhi, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

A direct-write method to fabricate a strain sensor directly on a structure of interest is reported. In this method, a commercial graphene ink is printed as a square patch (6 mm square) on the structure. The patch is dried at 100 °C for 30 min to remove residual solvents but the printed graphene remains in an insulative state. By scanning a focused laser (830 nm, 100 mW), the graphene becomes electrically conductive and exhibits a piezoresistive effect and a low temperature coefficient of resistance of −0.0006 °C−1. Using this approach, the laser defines a strain sensor pattern on …


Microstructures And High-Temperature Self-Lubricating Wear-Resistance Mechanisms Of Graphene-Modified Wc-12co Coatings, Haoliang Tian, Changliang Wang, Mengqiu Guo, Yongjing Cui, Junguo Gao, Zhihui Tang Aug 2021

Microstructures And High-Temperature Self-Lubricating Wear-Resistance Mechanisms Of Graphene-Modified Wc-12co Coatings, Haoliang Tian, Changliang Wang, Mengqiu Guo, Yongjing Cui, Junguo Gao, Zhihui Tang

Friction

To reduce the friction coefficient of cobalt-cemented tungsten carbide (WC-12Co) wear-resistant coatings, graphene was compounded into WC-12Co powder via wet ball milling and spray granulation. Self-lubricating and wear-resistant graphene coatings were prepared via detonation gun spraying. The presence, morphologies, and phase compositions of graphene in the powders and coatings that are obtained through different powder preparation processes were analyzed. The analysis was performed using the following technologies: energy-dispersive X-ray-spectroscopy (EDXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The mechanical properties of the coatings were studied using a microhardness tester and a universal drawing machine. The friction …


Advances In The Synthesis And Application Of Anti-Fouling Membranes Using Two-Dimensional Nanomaterials, Asif Shahzad, Jae Min Oh, Mudassar Azam, Jibran Iqbal, Sabir Hussain, Waheed Miran, Kashif Rasool Aug 2021

Advances In The Synthesis And Application Of Anti-Fouling Membranes Using Two-Dimensional Nanomaterials, Asif Shahzad, Jae Min Oh, Mudassar Azam, Jibran Iqbal, Sabir Hussain, Waheed Miran, Kashif Rasool

All Works

This article provides a comprehensive review of the recent progress in the application of advanced two-dimensional nanomaterials (2DNMs) in membranes fabrication and application for water purification. The membranes fouling, its types, and anti-fouling mechanisms of different 2DNMs containing membrane systems are also discussed. The developments in membrane synthesis and modification using 2DNMs, especially graphene and graphene family materials, carbon nanotubes (CNTs), MXenes, and others are critically reviewed. Further, the application potential of next-generation 2DNMs-based membranes in water/wastewater treatment systems is surveyed. Finally, the current problems and future opportunities of applying 2DNMs for anti-fouling membranes are also debated.


Fabrication And Characterization Of Photodetector Devices Based On Nanostructured Materials: Graphene And Colloidal Nanocrystals, Wafaa Gebril Jul 2021

Fabrication And Characterization Of Photodetector Devices Based On Nanostructured Materials: Graphene And Colloidal Nanocrystals, Wafaa Gebril

Graduate Theses and Dissertations

Photodetectors are devices that capture light signals and convert them into electrical signals. High performance photodetectors are in demand in a variety of applications, such as optical communication, security, and environmental monitoring. Among many appealing nanomaterials for novel photodetection devices, graphene and semiconductor colloidal nanocrystals are promising candidates because of their desirable and unique properties compared to conventional materials.

Photodetector devices based on different types of nanostructured materials including graphene and colloidal nanocrystals were investigated. First, graphene layers were mechanically exfoliated and characterized for device fabrication. Self-powered few layers graphene phototransistors were studied. At zero drain voltage bias and room …


Review: Factors Affecting Composite Laminates Against Lightning Strikes, Aaryan Manoj Nair Jul 2021

Review: Factors Affecting Composite Laminates Against Lightning Strikes, Aaryan Manoj Nair

Publications and Research

Lightning strike protection (LSP) have recently been a newly developing field particularly with the emergence of graphene thin film integration into carbon fiber composite structures. This technology has a widespread application in airplanes, wind turbines, and other instruments which are susceptible to frequent lightning strikes. Electrical discharge of the instrument in a safe manner is vital for the safety of the passengers (in the case of flights) as well as the integrity of the aircraft structures because of their specific mechanical and structural properties, which are essential for their functioning. The purpose of the study is to fabricate graphene thin …


Investigation Of Bipolar Electrochemically Exfoliated Graphene For Supercapacitor Applications, Iman Khakpour Jun 2021

Investigation Of Bipolar Electrochemically Exfoliated Graphene For Supercapacitor Applications, Iman Khakpour

FIU Electronic Theses and Dissertations

Developing a reliable, simple, cost-efficient and eco-friendly method for scale-up production of high-quality graphene-based materials is essential for the broad applications of graphene. Up to now, various manufacturing methods have been employed for synthesizing high quality graphene, however aggregation and restacking has been a major issue and the majority of commercially available graphene products are actually graphite microplates. In this study, bipolar electrochemistry techniques have been used to exfoliate and deposit graphene nanosheets in a single-step process to enable high performance device application.

In the first part of this study, bipolar electrochemistry concept is utilized to design a single-step and …


Graphene As A Shielding Material For Sar Reduction In Human Head Using Rectangular And Circular Patch Antenna, Alka Singla Er., Anupma Marwaha Dr., Sanjay Marwaha Dr. Jun 2021

Graphene As A Shielding Material For Sar Reduction In Human Head Using Rectangular And Circular Patch Antenna, Alka Singla Er., Anupma Marwaha Dr., Sanjay Marwaha Dr.

Karbala International Journal of Modern Science

Nanomaterials pave the way for better performance in wireless applications due to their unique properties. Nowadays, these have been used as shield material in dipole antennas for a solution of reduction in SAR value. This work proposes the use of emerging graphene nanomaterial by comparing the performance for two different shapes of patch antenna namely rectangular and circular patch. With the growth in technology, the protection of human health is also mandatory so the work is planned to use graphene as a shielding material for SAR reduction in the human brain and it is proved that for rectangular and circular …


Wastewater Remediation Technologies Using Macroscopic Graphene-Based Materials: A Perspective, Rajan Arjan Kalyan Hirani, Abdul Hannan Asif, Nasir Rafique, Lei Shi, Shu Zhang, Hong Wu, Hongqi Sun May 2021

Wastewater Remediation Technologies Using Macroscopic Graphene-Based Materials: A Perspective, Rajan Arjan Kalyan Hirani, Abdul Hannan Asif, Nasir Rafique, Lei Shi, Shu Zhang, Hong Wu, Hongqi Sun

Research outputs 2014 to 2021

Three-dimensional (3D) graphene-based macrostructures are being developed to combat the issues associated with two-dimensional (2D) graphene materials in practical applications. The 3D macrostructures (3DMs), for example, membranes, fibres, sponges, beads, and mats, can be formed by the self-assembly of 2D graphene-based precursors with exceptional surface area and unique chemistry. With rational design, the 3D macrostructures can then possess outstanding properties and exclusive structures. Thanks to various advantages, these macrostructures are competing in a variety of applications with promising performances unlike the traditional activated carbons, biochars and hydrochars, which have less flexibilities for modifications towards versatile applications. However, despite having such …


Biofabricated Constructs Of Carbon-Based Nanoparticles With Mesenchymal Stem Cells For Orthopedic Repair, Steven D. Newby May 2021

Biofabricated Constructs Of Carbon-Based Nanoparticles With Mesenchymal Stem Cells For Orthopedic Repair, Steven D. Newby

Doctoral Dissertations

Breakthroughs in tissue engineering are moving at a rapid rate especially in the regenerative bone biofabrication. Technology growth in the field of additive manufacturing (AM) such 3D bioprinting which provides the ability to create biocompatible 3D construct on which a cell source could be seeded is an encouraging substitute to autologous grafts.

This present research aims to biofabricate a construct for bone tissue engineering using AM technology. The biocompatible material was chosen corresponding to bones extracellular matrix (ECM) composition, which demonstrates an inorganic and organic development phase: Poly (lactic-glycolic acid) was chosen as the polymeric matrix of the compound, due …


Development Of A Laser-Assisted Chemical Vapor Deposition (Cvd) Technique To Grow Carbon-Based Materials, Abiodun Ademola Odusanya May 2021

Development Of A Laser-Assisted Chemical Vapor Deposition (Cvd) Technique To Grow Carbon-Based Materials, Abiodun Ademola Odusanya

MSU Graduate Theses

Carbon-based materials (CBMs) including graphene, carbon nanotubes (CNT), highly ordered pyrolytic graphite (HOPG), and pyrolytic carbon (PyC) have gained so much attention in research in recent years because of their unique electronic, optical, thermal, and mechanical properties. CBMs are relatively very stable and have minimal environmental footprint. Various techniques such as mechanical exfoliation, pulsed laser deposition, and chemical vapor deposition (CVD) have been used to grow CBMs and among them thermal CVD is the most common. This study aims to explore ways of reducing the energy requirement to produce CBMs, and for that, a novel pulsed laser-assisted CVD technique had …


Design Of Graphene-Based Sensors For Nucleic Acids Detection And Analysis, Asma’ Wasfi Fayez Mustafa Apr 2021

Design Of Graphene-Based Sensors For Nucleic Acids Detection And Analysis, Asma’ Wasfi Fayez Mustafa

Dissertations

DNA (Deoxyribonucleic Acid) is the blueprint of life as it encodes all genetic information. In genetic disorder such as gene fusion, Copy Number Variation (CNV), and single nucleotide polymorphism, Nucleic acids such as DNA bases detection and analysis is used as the gold standard for successful diagnosis. Researchers have been conducting rigorous studies to achieve genome sequences at low cost while maintaining high accuracy and high throughput. A quick, accurate, and low-cost DNA detection approach would revolutionize medicine. Genome sequence helps to enhance people’s perception of inheritance, disease, and individuality. This research aims to improve DNA bases detection accuracy, and …


Recent Advances In Terahertz Photonic Technologies Based On Graphene And Their Applications, Tianjing Guo, Christos Argyropoulos Mar 2021

Recent Advances In Terahertz Photonic Technologies Based On Graphene And Their Applications, Tianjing Guo, Christos Argyropoulos

Faculty Publications from the Department of Electrical and Computer Engineering

Graphene is a unique 2D material that has been extensively investigated due to its extraordinary photonic, electronic, thermal, and mechanical properties. Excited plasmons along its surface and other unique features are expected to play an important role in many emerging photonic technologies with drastically improved and tunable functionalities. This review is focused on presenting several recently introduced photonic phenomena based on graphene, beyond its usual linear response, such as nonlinear, active, topological, and nonreciprocal effects. The physical mechanisms and various envisioned photonic applications corresponding to these novel intriguing functionalities are also reported. The presented graphene-based technologies promise to revolutionize the …


Flexible Nanopaper Composed Of Wood-Derived Nanofibrillated Cellulose And Graphene Building Blocks, Qing Li, Ming Dai, Xueren Qian, Tian Liu, Zhenbo Liu, Yu Liu, Ming Chen, Wang He, Suqing Zeng, Yu Meng, Chenchen Dai, Jing Shen, Yingtao Liu, Wenshuai Chen, Wenbo Liu, Ping Lu Jan 2021

Flexible Nanopaper Composed Of Wood-Derived Nanofibrillated Cellulose And Graphene Building Blocks, Qing Li, Ming Dai, Xueren Qian, Tian Liu, Zhenbo Liu, Yu Liu, Ming Chen, Wang He, Suqing Zeng, Yu Meng, Chenchen Dai, Jing Shen, Yingtao Liu, Wenshuai Chen, Wenbo Liu, Ping Lu

Faculty Scholarship for the College of Science & Mathematics

Nanopaper has attracted considerable interest in the fields of films and paper research. However, the challenge of integrating the many advantages of nanopaper still remains. Herein, we developed a facile strategy to fabricate multifunctional nanocomposite paper (NGCP) composed of wood-derived nanofibrillated cellulose (NFC) and graphene as building blocks. NFC suspension was consisted of long and entangled NFCs (10–30 nm in width) and their aggregates. Before NGCP formation, NFC was chemically modified with a silane coupling agent to ensure that it could interact strongly with graphene in NGCP. The resulting NGCP samples were flexible and could be bent repeatedly without any …


Quantum Simulations Of Low Dimensional Systems And Analytic Continuation Of Imaginary Time Correlation Functions, Nathan Scott Nichols Jan 2021

Quantum Simulations Of Low Dimensional Systems And Analytic Continuation Of Imaginary Time Correlation Functions, Nathan Scott Nichols

Graduate College Dissertations and Theses

For over thirty years, a long standing problem in quantum many-body physics has been to reliably extract dynamical information from imaginary time quantum Monte Carlo data. I report on a new method developed using modern evolutionary computation routines to approach this notoriously ill-posed problem. Motivation towards a solution will be presented as a brief summary of work on quantum simulations of low dimensional systems including helium on strained graphene and helium confined within rare gas plated mesoporous silica. The Differential Evolution for Analytic Continuation (DEAC) algorithm reconstructs the dynamic structure factor from imaginary time density-density correlations at zero and finite …


Semi-Empirical Modeling Of Liquid Carbon's Containerless Solidification, Philip C. Chrostoski Jan 2021

Semi-Empirical Modeling Of Liquid Carbon's Containerless Solidification, Philip C. Chrostoski

Doctoral Dissertations

“Elemental carbon has important structural diversity, ranging from nanotubes through graphite to diamond. Previous studies of micron-size core/rim carbon spheres extracted from primitive meteorites suggest they formed around such stars via the solidification of condensed carbon-vapor droplets, followed by gas-to-solid carbon coating to form the graphite rims. Similar core/rim particles result from the slow cooling of carbon vapor in the lab. The long-range carbon bond-order potential was used to computationally study liquid-like carbon in (1.8 g/cm3) periodic boundary (tiled-cube supercell) and containerless (isolated cluster) settings. Relaxations via conjugate-gradient and simulated-annealing nucleation and growth simulations using molecular dynamics were …


Experimental Validation Of Bulk-Graphene As A Thermoelectric Generator, Muhammad Uzair Khan, Amir Naveed, Syed Ehtisham Gillani, Dawar Awan, Muhammad Arif, Shaista Afridi, Muhammad Hamyun, Muhammad Asif, Saadia Tabassum, Muhammad Sadiq, Muhammad Lais, Muhammad Aslam, Saeed Ullah Jan, Zeeshan Ahad Jan 2021

Experimental Validation Of Bulk-Graphene As A Thermoelectric Generator, Muhammad Uzair Khan, Amir Naveed, Syed Ehtisham Gillani, Dawar Awan, Muhammad Arif, Shaista Afridi, Muhammad Hamyun, Muhammad Asif, Saadia Tabassum, Muhammad Sadiq, Muhammad Lais, Muhammad Aslam, Saeed Ullah Jan, Zeeshan Ahad

Research outputs 2014 to 2021

Quest for alternate energy sources is the core of most of the research activities these days. No matter how small or large amount of energy can be produced by utilizing the non-conventional techniques and sources, every bit of innovation can reshape the future of energy. In this work, experimental analysis of the thermoelectric (TE) properties of bulk-graphene in the temperature range of (303 to 363) K is presented. Graphene powder was pressed to form a pellet which was used to fabricate the TE device. The effects of temperature on the Seebeck coefficient, electrical and thermal conductivities, and the dimensionless figure …