Materials Science and Engineering Commons^™

Deep Euteceic Solvents-Assisted Synthesis Of Novel Network Nanostructures For Accelerating Formic Acid Electrooxidation, Jun-Ming Zhang, Xiao-Jie Zhang, Yao Chen, Ying-Jian Fan, You-Jun Fan, Jian-Feng Jia

Journal of Electrochemistry

Deep eutectic solvents (DESs) have been reported as a type of solvent for the controllable synthesis of metal nanostructures. Interestingly, flower-like palladium (Pd) nanoparticles composed of staggered nanosheets and nanospheres are spontaneously transformed into three-dimensional (3D) network nanostructures in choline chloride-urea DESs using ascorbic acid as a reducing agent. Systematic studies have been carried out to explore the formation mechanism, in which DESs itself acts as a solvent and soft template for the formation of 3D flower-like network nanostructures (FNNs). The amounts of hexadecyl trimethyl ammonium bromide and sodium hydroxide also play a crucial role in the anisotropic growth and …

Fe Nanoparticles Encapsulated In N-Doped Porous Carbon For Efficient Oxygen Reduction In Alkaline Media, Chun-Yan Li, Rui Zhang, Xiao-Jie Ba, Xiao-Le Jiang, Yao-Yue Yang

Journal of Electrochemistry

Rational design and synthesis of non-precious-metal catalyst plays an important role in improving the activity and stability for oxygen reduction reaction (ORR) but remains a major challenge. In this work, we used a facile approach to synthesize iron nanoparticles encapsulated in nitrogen-doped porous carbon materials (Fe@N-C) from functionalized metal-organic frameworks (MOFs, MET-6). Embedding Fe nanoparticles into the carbon skeleton increases the graphitization degree and the proportion of graphitic N as well as promotes the formation of mesopores in the catalyst. The Fe@N-C-30 catalyst showed the excellent ORR activity in alkaline solutions (E₀ = 0.97 V vs. RHE, E_{1/2 …}

Effective Nanomembranes From Chitosan/Pva Blend Decorated Graphene Oxide With Gum Rosin And Silver Nanoparticles For Removal Of Heavy Metals And Microbes From Water Resources, Mohamed Morsy

Nanotechnology Research Centre

No abstract provided.

Flexural Wave Manipulation By Non-Hermitian Planar Elastic Metasurface, Katerina Stojanoska

Theses and Dissertations

It has been demonstrated that metasurfaces with spatially asymmetric inner geometry exhibit unidirectional scattering effects, which can be used to control waves in a directional fashion. In this thesis, a planar Non-Hermitian elastic metasurface exhibiting unidirectional focusing of flexural waves is proposed. Asymmetrically loaded piezoelectric disks and metallic blocks comprise the unit cells. By using a negative capacitance shunting, a tunable material loss is embedded into the system. With suitable engineering of the induced loss profile, resonating building blocks are designed, which are capable of independently accessing unidirectional zero reflection. A planar metasurface is then created so that constructive interference …

Enhanced Throughput Of Aligned Polyacrylonitrile Nanofiber Manufacturing Via High-Speed Centrifugal Spinning, Jason Glen Ippolito

Theses and Dissertations

Centrifugal spinning is noteworthy due to its high fiber throughput rate compared to other nanofiber manufacturing platforms. It is capable of producing fibers in the nanoscale diameter range from a multitude of polymers, such as polyacrylonitrile (PAN). With a traditional centrifugal spinner, fiber can be rapidly spun and collected on static posts. However, the use of static posts inevitably forms a dense ring of fiber after a short period of time, and this fiber build up can halt the spinning process. In this work, the factors that influence the throughput and scalability of highly aligned centrifugally spun PAN fibers are …

The Neighborhood As An Energy-Generating Community The Case Of El-Banafseg Residential Neighborhood, East Cairo, Mona Helmy, Amany Micheal

Architectural Engineering

No abstract provided.

Effect Of Cr And Ni Concentrations On Resilience Of Cast Nb-Alloyed Heat Resistant Austenitic Steels At Extreme High Temperatures, Simon N. Lekakh, Mario F. Buchely, Mei Li, Larry Godlewski

Materials Science and Engineering Faculty Research & Creative Works

Austenitic Cr–Ni Alloyed Heat Resistant Steels with Nb Additions Are Used for Intensively Thermo-Mechanically Loaded Cast Components Working in Extreme High Temperature Oxidizing Environment. their Performance during Static Oxidation and Transient Thermo-Mechanical Loading Was Investigated to Recommend an Optimal Cost-Effective Cr/Ni Composition of Nb-Alloyed Austenitic Class Steels. the Static Oxidation and Transient Thermo-Mechanical Behavior of Three Austenitic Steels with Different Cr/Ni Alloying Levels Were Investigated and Compared for Variety of Working Conditions. Static Oxidation Was Performed between 900 °C and 1000 °C in Air for 400 H. the Critical Temperature Which Increases Spallation during Static Oxidation Was Determined for Each …

Method Of Evanescently Coupling Whispering Gallery Mode Optical Resonators Using Liquids, Hengky Chandrahalim, Kyle T. Bodily

AFIT Patents

The present invention relates to evanescently coupling whispering gallery mode optical resonators having a liquid coupling as well as methods of making and using same. The aforementioned evanescently coupling whispering gallery mode optical resonators having a liquid couplings provide increased tunability and sensing selectivity over current same. The aforementioned. Applicants’ method of making evanescent-wave coupled optical resonators can be achieved while having coupling gap dimensions that can be fabricated using standard photolithography. Thus economic, rapid, and mass production of coupled WGM resonators-based lasers, sensors, and signal processors for a broad range of applications can be realized.

Evaluating The Potential Of Geopolymer Concrete As A Sustainable Alternative For Thin White-Topping Pavement, Sathvik S. Chandra, Pshtiwan Shakor, Sarwar Mohmmad, Bankole O. Awuzie, Atul K. Singh, Abishek Rauniyar, M Karakouzian

Civil and Environmental Engineering and Construction Faculty Research

Introduction:

The construction industry uses a large quantity of natural materials in the production of concrete. Although attempts to incorporate green materials in concrete began years ago, not every building uses such materials today, and roadways, particularly, still rely on unsustainable materials.

Methods:

Therefore, this study used alternative materials, including fly ash, manufactured sand aggregates, and different molarities of alkaline activators, to incorporate waste byproducts in a geopolymer concrete white-topping pavement layer. Recent developments have led to the emergence of geopolymers as distinct classes of materials. In the 1990s, fly ash-based geopolymers became more popular than other kinds, as they …

Confined Growth Of Perovskite Stabilized By Strain Engineering, Xucheng Tao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Halide perovskite has been extensively studied for its excellent optoelectronic properties. In this project, we want to explore some range of band gap that conventional 2D materials could not have. To overcome this challenge, we aimed to produce two-dimensional (2D) perovskites with large scale which is suitable for device fabrication and improve its stability using strain engineering. To prepare such 2D perovskite, we tried 2D transformation first and then decided to use confined growth to optimize result. For strain engineering, we employed sputtered nickel as an external stressor.

So far, we have produced multilayer polycrystalline perovskites material close to atomic …

A Prediction Of Young's Modulus For Tin Containing Phosphate Glasses Using Quantitative Structural Information, Tatsuki Shimizu, Akira Saitoh, Uwe Hoppe, Grégory Tricot, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

A Rigid Unit Packing Fraction (RUPF) Model Was Used to Better Understand the Influence of Local Structural Units on the Young's Elastic Modulus (E) of Binary and Ternary Tin Phosphate Glasses. Quantitative Analyses of the Units that Constitute the Glass Structure, Obtained from X-Ray/neutron Diffraction and 31P MAS-NMR Spectroscopy, Were Used to Calculate Polyhedral Packing Fractions that, with Tabulated Bond Dissociation Energies, Were Used to Predict E based on a Modification of the Makashima-Mackenzie Relationship, Which Uses Ion Sizes to Calculate Packing Fractions. Predictions based on the RUPF Model Are Better Than Those based on Ion Sizes, and Extending the …

Two-Dimensional Field Effect Transistor, Yimeng Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

As silicon-based field-effect transistors (FETs) approach their physical limits with channel lengths approaching 5 nm, the search for new semiconductor materials that can surpass this limit has become urgent. Two-dimensional layered semiconductor nanomaterials, represented by graphene, have emerged as promising candidates due to their unique physical, mechanical, and chemical properties. Unlike traditional silicon-based FETs, two dimensional (2D) layered nanomaterials are held together by van der Waals forces between layers, with no dangling bonds on the material surface, which can effectively address the short-channel effect issue faced by traditional silicon-based FETs. However, unlike traditional silicon-based FETs, which have matured fabrication systems, …

Memristive Behavior And Its Applications In Different Materials., Mingyang Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

The huge amount of data calculation requires the next generation non-volatile memory (NVM) technology to have the characteristics of large storage capacity and fast read/write speed. The storage and computing are separated in the traditional von Neumann architecture-based hardware platforms. The data transport between information processing and storage are causing increasing time latency, which is called von Neumann Bottleneck. Memristor, as a basic circuit component, could combine perception, storage, and computing in a single component, which has a very wide range of application prospectives. In this paper, we investigate binary oxide memristor and 2D material memristor, including their structural design …

Piezoelectric And Conductive Polymer Based Flexible Devices Enabling Cardiovascular Health Sensing And Energy Harvesting, Andrew Closson

Dartmouth College Ph.D Dissertations

Piezoelectric materials show great promise for low-power wearable and implantable sensing, but their rigidity makes it challenging to integrate them with biological tissue. To address this, researchers have started exploring polymer-based functional materials that offer flexibility and are suitable for interfacing with the human body. However, these materials are still in their early stages, and a framework is necessary to illustrate how these materials, in conjunction with novel fabrication techniques and device designs, can enable the development of multi-functional sensing and energy harvesting devices.

This thesis utilizes highly scalable fabrication methods for functional polymers to build and test a flexible …

Synthesis And Characterization Of Polyaniline-Based High-Performance Carbon For Energy Storage Applications, Udeshika Kangane Arachchige

Electronic Theses & Dissertations

With the increase in global population, the demand for the energy required for daily activities including household necessities, electronic and electric devices, etc. enhances at an alarming proportion. Under these circumstances, supercapacitors (SCs) have attracted great attention as electrochemical energy storage devices. Nowadays, most commercially available supercapacitors are composed of metallic compounds. Due to the high consumption, and limited availability of these elements, it is necessary to find an alternative, effective, low-cost materials in place of using it. With the purpose of achieving high electrochemical performance, this research work focuses on developing carbon derived from polyaniline (PANI) as an efficient …

Machine Learning Based Prediction Models For Silicon Heterojunction Solar Cell Optimization, Rahul Jaiswal

Electrical and Computer Engineering ETDs

Silicon heterojunction solar cell of Heterojunction with Thin Intrinsic Layer (HIT) structure is a commercially available technology, and its market share will significantly increase by the next decade. With such a significant market share, any minor improvement in the device’s overall efficiency can be beneficial three folds - customer return on investment, industry revenue, and the overall carbon footprint (from manufacturing to recycling/ disposing of the device). Conventionally, device optimization for solar cells has been achieved using a hit & trial approach where multiple experiments are done to evaluate the best process conditions and device parameters. This approach has some …

Synthesis And Characterization Of Sodium Cathode Materials, He Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

As sodium batteries hold great promise as a next-generation energy storage device to replace lithium batteries, the development of sodium battery materials has become increasingly urgent. The current study aims to investigate two potential sodium-ion battery cathode materials, Sodium Vanadium Phosphate, and Sodium Manganese Hexacyanoferrate, optimize the experimental procedures, conduct a systematic analysis of material properties and characterization, and ultimately determine the ideal synthesis conditions for these materials.

In the first part of the study, we focused on optimizing the synthesis of Sodium Vanadium Phosphate. By investigating various synthesis conditions, such as annealing temperature, pressure, ascorbic acid content, and material …

Study Of A Carbon Fiber Reinforced Polymer Composite Using A Biobased Polyurethane As A Thermosetting Resin, Teddy Mageto

Electronic Theses & Dissertations

Carbon Fiber Reinforced Polymer composites (CFRP) have garnered increasing interest in recent years especially in the aerospace and automobile industries where they are gradually replacing metals as structural materials. This is owing to their light weight, high strength, high modulus, and excellent strength-to-weight ratio. Polymers are typically used as thermosetting resins in these composites. However, the synthesis of polymers currently is conducted via petrochemical processes which leads to adverse effects on the environment. To this end, in this work a biobased Polyurethane (PU) was used as a thermosetting resin in a CFRP. The biobased PU was synthesized by the reaction …

Development Of Novel Sensor Coating Methodology To Enable Understanding Of Fouling Mechanisms On Ion Exchange Membranes, Andrew Ulmer

Honors Theses

As populations expand and natural water resources are depleted, severe droughts and limited access to clean water have become an increased threat to areas across the world. Effective and economic water treatment methods such as electrodialysis (ED) are vital for combating these threats, especially in developing nations and secluded locations. Organic foulant adsorption on the surface of ion exchange membranes severely limits the capabilities of water desalination systems such as ED along with significantly increasing maintenance costs. Understanding characteristics such as the total amount and rate at which these foulants at specific concentrations adsorb and desorb to the membranes is …

Integrating Steel Slag Aggregates Into Asphalt Paving By Harmonizing Availability, Quality, Economics, And The Environment, Timothy R. Murphy

Theses and Dissertations

This thesis provides guidance on how to balance matters related to the environmental stewardship, market sources, origin and uses, material properties, performance, and economic impact of using slag materials in pavements. The literature on this topic provides numerous references on the use of slag materials for specific applications, and this thesis aims to make use of those references along with other data from the author to describe slag materials from a holistic perspective and provide some suggestions for balancing several factors that impact optimal use of this resource within pavement structures. Discussion is given to the increased importance of recycling …