Engineering Commons^™

Development Of The Composition Of A Composite Material Based On Thermoreactive Binder Ed-20, Umida Ziyamukhamedova, Gavhar Miradullayeva, Erkin Rakhmatov, Jasur Nafasov, Mavtuna Inogamova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study is to determine the effect of the type of structural modifier and filler on the structure formation and technological properties of potting composite polymeric materials (HCPM) and protective coatings for sheet and complex-configuration technological equipment, taking into account their rheological properties. Compositions of composite polymer materials based on a thermosetting binder of epoxy-diane resin ED-20 filled with a mineral filler - kaolin modified with gassipol resin (GS) - were developed using Newton's interpolation formula and the Lagrange method. The optimal amount of gossypol resin determined in the composition of the composite – in the amount …

Effect Of Talc On The Properties Of A Compound Based On Ethylene-Propylene Copolymer, Ikromjon Usmanov, Farrukh Kurbanbekov, Bobir Aykhodjaev, Ravshan Adilov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research is to study the possibility of replacing Korean-made talc with inexpensive talc from an Afghan deposit, processed in Uzbekistan and used for the production of polypropylene compounds. In the future, these compounds are used for the manufacture of plastic car parts. A block copolymer produced by Uz Kor Gaz Chemical was chosen as a binder. For this, the influence of the content and type of talc on the properties of a compound based on an ethylene-propylene copolymer was studied.

The properties of the obtained compounds checked using ISO standards. The fractional composition of the studied …

Physical And Chemical Studies Of Overroof Rocks Of Clay Shales Of The Dzherdanak Deposit, Mastura Aripova, Ivan Levitskiy, Khabiba Khamidova, Odelbek Ammanov

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this study is study of the physical and chemical properties of the overburden of the Dzherdanak deposit. The chemical and mineralogical composition of the overburden of the Djerdanak deposit has been studied by the methods of X-ray and thermography, electron microscopy and infrared spectroscopy. The main phases are quartz, kaolinite and muscovite. The study of the fine structure of the rock under an electron microscope showed the homogeneity of the rock with pronounced uniform inclusions, which is preserved even after firing. Changes in the rock after firing at 1050 °C have been determined. The formation of mullite …

On The Possibility Of Obtaining Effective Phosphoric Fertilizers As A Result Of Interaction Of Phosphorite-Containing Waste With Activated Glauconite Sands, Nargisa Takhirova, Fazlidin Khudoyberdiev, Shahlo Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

These studies are devoted to the study of the chemical properties obtained as a result of chemical activation of glauconite and further neutralization of activated glauconite by waste products of phosphorite concentrates. Based on the results of X-ray structural studies of the obtained products, it is possible to obtain granular complex fertilizers after adding phosphorites to the system. Activation with mineral acids (nitric or sulfuric) should be carried out to accelerate the transformation of minerals from glauconite sands into an easily digestible form. Since the obtained compounds form an acidic environment, it is necessary to neutralize them. The neutralization process …

Study Of Sorption Of Rhenium Ions On Solid Extragents, Otabek Pardaev, Dildora Ilkhomjonkizi Khakimboeva, Shahlo Daminova, Ulugbek Sharafutdinov, Sharipov Khasan Turabovich

CHEMISTRY AND CHEMICAL ENGINEERING

In this work, the aim is to study the possibility of extracting rhenium from sulfuric acid solutions by sorption of impregnated sorbents based on polystyrene-divinylbenzene (MN202) and an organic reagent MAB (2-amino-1-methylbenzimidazole).New sorbent based on MN202 (Purolite) impregnated with organic reagents have been obtained and investigated. The sorbent characteristics determined using SEM, XRD and FTIR methods. The optimal conditions for the sorption of rhenium (VII) ions for the "element-sorbent" systems have been established. Under static conditions, the sorption of rhenium on impregnated sorbents in a sulfuric acid solution was studied in the periodic system with respect to the contact time, …

Fabrication And Characterization Of Manganese Oxide Surfaces From Polymer-Based Fiber Precursors, Molly C. Brockway

Graduate Theses & Non-Theses

Supercapacitors are an energy storage technologycombining properties of both capacitors and batteries to deliver high power and energydensities. Supercapacitors store charge through electrostatic and faradaic interactions between the electrode and ionic electrolyte. By improving the physical structure of electrodes, the interfacial area where energy storage occurs can be increased and electrochemical performance improved. New, fibrous, manganese oxide web-based structures tested for use as a supercapacitor electrode were fabricated by electrospinning and direct calcinationof metal salt-containing polymer fibers, and the effects of fabrication parameters on electrochemical performance were investigated. Data show that high polymer concentrations and low oxide precursor concentrations during …

Machine Learning For High-Fidelity Prediction Of Cement Hydration Kinetics In Blended Systems, Rachel Cook, Taihao Han, Alaina Childers, Cambria Ryckman, Kamal Khayat, Hongyan Ma, Jie Huang, Aditya Kumar

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The production of ordinary Portland cement (OPC), the most broadly utilized man-made material, has been scrutinized due to its contributions to global anthropogenic CO₂ emissions. Thus -- to mitigate CO₂ emissions -- mineral additives have been promulgated as partial replacements for OPC. However, additives -- depending on their physiochemical characteristics -- can exert varying effects on OPC's hydration kinetics. Therefore -- in regards to more complex systems -- it is infeasible for semi-empirical kinetic models to reveal the underlying nonlinear composition-property (i.e., reactivity) relationships. In the past decade or so, machine learning (ML) has arisen as a promising, …

Stiffness Degradation In Fatigue Life Of Composites Using Dielectric State Variables, Muthu Ram Prabhu Elenchezhian, Partha Pratim Das, Minhazur Rahman, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

Composite materials are widely used in aerospace and automotive structures for decades and over the years the community has gained a better understanding of the damage and failure modes of composites under fatigue. In this article, a dielectric characterization methodology for in-situ monitoring of composites under fatigue environments is proposed. A novel method of measuring the dielectric state variables in Broadband Dielectric Spectroscopy (BbDS) using Extremely Conductive Silver Epoxy Adhesive (ECSEA) paste is presented. These dielectric state variables serve to identify the precursor of the beginning of the end of life of the composite material under fatigue loading. The reliability …

Perovskite Film Formation For Solar Cell Absorbers: Effects Of Substrate Modification, Mirra M. Rasmussen, Kyle M. Crowley, Ina T. Martin

Student Scholarship

As perovskite solar cell efficiencies have risen rapidly, practical constraints have made durability a critical concern. Whereas much attention has been paid to the development of the perovskite absorber layer, the charge transport layers can also be engineered to better the performance and stability of the device. This work uses the molecular modifier bromopropyltrimethoxysilane (BPTMS) to alter the interface between indium tin oxide (ITO, a common thin film solar cell transparent electrode) and methylammonium lead iodide (MAPbI3, a common perovskite absorber) to improve the morphology and stability of the perovskite absorber film. The substrate, molecular modifier, and perovskite film were …

Poly(2-Hydroxyethyl Methacrylate) Hydrogels For Contact Lens Applications–A Review, Kushendarsyah Saptaji, Nurlaely Rohmatul Iza, Sinta Widianingrum, Vania Katherine Mulia, Iwan Setiawan

Makara Journal of Science

The emerging technology in biomedical engineering requires biocompatible materials, which are also referred to as biomaterials. For a material to be considered biocompatible, it should not interact with human tissues in a harmful way, and vice versa. Various properties of biocompatible materials, such as mechanical and optical properties, have to be considered for different biomedical applications. One of the most popular applications of biomaterials is for contact lenses. Hydrogels, specifically poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels, are among the most popular ones in ophthalmologic applications, especially in soft contact lenses. This paper reviews the use of PHEMA hydrogels as one of the …

Development Of Carbon And Silicon Carbide Based Microelectrode Implantable Neural Interfaces, Chenyin Feng

USF Tampa Graduate Theses and Dissertations

The use of neural modulation techniques to treat nervous system disorders, as well as neural recording to study brain function, continues to be of intense interest around the world. Due to the need to treat diseases such as Parkinson’s, dementia, depression and return normal function to patients suffering from nervous system damage and trauma, neural implants continue to be developed globally. One of these devices, the microelectrode implantable neural interface (mINI), has been rapidly developed, thanks to advanced semiconductor fabrication processes. However, the long-term reliability of present-day devices has still to be demonstrated and is delaying the application of this …

Improved Predictive Modeling Techniques For Non-Linear Solder Material Behavior, Arman Millian Ahari

Dissertations and Theses

Accurate prediction of fatigue life of solder joints in electronic packaging applications becomes of critical importance as semiconductor device technology and manufacturing constraints grow in complexity. To gain visibility on IC device performance and reliability, thermo-mechanical simulation is performed based on a unified, viscoplastic material model, which is dependent on nine parameters.

In this study, an improved method of Anand parameter extraction, which involves curve-fitting non-linear experimental stress data, is proposed to improve the accuracy of numerical predictions for solder reliability. Theoretical equations for uni-axial stress-strain response and creep response are derived, then details on their relevance to experimental and …

Biodegradable Nanocomposite Multifunctional Packaging Film For Fruits, Kalpani Y. Perera, Shubham Sharma, Dileswar Pradhan, Amit Jaiswal, Swarna Jaiswal

Articles

Biopolymers have been used in food packaging in recent years due to high pollution rates and decreased biodegradation of synthetic polymers. Chitosan (CH) and Sodium alginate (SA) are both biodegradable biopolymers with excellent film forming capability. TiO2 nanoparticles have high mechanical strength, degradation ability and antimicrobial properties, which are beneficial in food packaging. The aim of the current work is to develop the biodegradable multifunctional nanocomposite film for fruit (i.e., Pear) packaging applications. Bionanocomposite film was prepared by solvent casting method using CH-SA and various concentrations of TiO2. The multifunctional properties such as UV barrier, thermal, water retention, mechanical, chemical, …

Fabrication And Comparative Study Of Horizontal And Vertical Electrospun Protein-Polysaccharide Nanofiber Biomaterials, Ashley Rivera-Galleti

Theses and Dissertations

The use of biocompatible and biodegradable composite materials for biomedical applications has attracted the attention of many researchers in the past few years. In this study, we fabricated nanofibers of silk fibroin and cellulose and its derivatives to amalgamate their unique properties into a single material. The production of these nanofibers via electrospinning is of particular interest, and whereas several studies have been done on normal nanofibers, the formation of branched nanofibers is an exciting area not currently explored. Blend solutions are formed by dissolving silk and cellulose/cellulose acetate in formic acid separately and mixing to achieve the desired ratios. …

Mechanical Properties And Characterization Of Epoxy Composites Containing Highly Entangled As-Received And Acid Treated Carbon Nanotubes, Aaron Krieg, Julia A. King, Gregory M. Odegard, Timothy Leftwich, Leif K. Odegard, Paul D. Fraley, Ibrahim Miskioglu, Claire Jolowsky, Matthew Lundblad, Jin Gyu Park, Richard Liang

Michigan Tech Publications, Part 1

Huntsman–Merrimack MIRALON® carbon nanotubes (CNTs) are a novel, highly entan-gled, commercially available, and scalable format of nanotubes. As-received and acid-treated CNTs were added to aerospace grade epoxy (CYCOM® 977-3), and the composites were characterized. The epoxy resin is expected to infiltrate the network of the CNTs and could improve mechanical properties. Epoxy composites were tested for flexural and viscoelastic properties and the as-re-ceived and acid treated CNTs were characterized using Field-Emission Scanning and Transmission Electron Microscopy, X-Ray Photoelectron Spectroscopy, and Thermogravimetric Analysis. Composites containing 0.4 wt% as-received CNTs showed an increase in flexural strength, from 136.9 MPa for neat epoxy …

Excited-State Lifetimes Of Dna-Templated Cyanine Dimer, Trimer, And Tetramer Aggregates: The Role Of Exciton Delocalization, Dye Separation, And Dna Heterogeneity, Jonathan S. Huff, Daniel B. Turner, Olga A. Mass, Lance K. Patten, Christopher K. Wilson, Simon K. Roy, Matthew S. Barclay, Bernard Yurke, William B. Knowlton, Paul H. Davis, Ryan D. Pensack

Materials Science and Engineering Faculty Publications and Presentations

DNA-templated molecular (dye) aggregates are a novel class of materials that have garnered attention in a broad range of areas including light harvesting, sensing, and computing. Using DNA to template dye aggregation is attractive due to the relative ease with which DNA nanostructures can be assembled in solution, the diverse array of nanostructures that can be assembled, and the ability to precisely position dyes to within a few Angstroms of one another. These factors, combined with the programmability of DNA, raise the prospect of designer materials custom tailored for specific applications. Although considerable progress has been made in characterizing the …

First-Principles Magnetic Treatment Of The Uranium Nitride (100) Surface And Effect On Corrosion Initiation, Ember L. Sikorski, Brian J. Jaques, Lan Li

Materials Science and Engineering Faculty Publications and Presentations

The magnetic properties of uranium nitride (UN) surfaces are not well understood experimentally or computationally but they have a significant effect on UN performance as a nuclear fuel. We investigated ferromagnetic (FM), antiferromagnetic (AFM), nonmagnetic (NM), and three hybrid magnetic structures of the most stable UN surface (100). To account for electron correlation and metastability, a U-ramp was performed to an effective Hubbard U-term of 2.0 eV. FM was found to be the most energetically favorable magnetic structure. Type 1 AFM slab was optimized to a new magnetic structure consisting of (100) planes with either all spin-up electrons, all spin-down …

Seaweed Polysaccharide In Food Contact Materials (Active Packaging, Intelligent Packaging, Edible Films, And Coatings), Kalpani Y. Perera, Shubham Sharma, Amit K. Jaiswal, Swarna Jaiswal

Articles

Food contact materials (FCMs) are materials that come in contact with food products such as food packaging which play a significant role in the food quality and safety. Plastic, which is a major food packaging material, harms the eco-system, wildlife, and the environment. As a result, numerous researches have been in progress on alternative polymers, which has similar properties as plastic but is also environmentally friendly (biodegradable). In recent years, the utilization of seaweed polysaccharides has piqued interest due to its biodegradability, non-toxicity, antioxidant capabilities, and excellent film formation ability. However, it has a number of drawbacks such as low …

Effect Of Crystal Quality On Twinning Stress In Ni–Mn–Ga Magnetic Shape Memory Alloys, Andrew Armstrong, Peter Müllner

Materials Science and Engineering Faculty Publications and Presentations

Low twinning stress (TS) is a prerequisite for magnetic shape memory functionality in ferromagnetic martensites. We compare Ni₅₀Mn₂₈Ga₂₂ (nominal at.%) single crystals from four different producers to reveal the effect of crystal quality on the TS. Near the reverse martensite transformation, the TS is generally low, about 1 MPa, regardless of mosaicity of up to 1.7° and chemical composition deviations of up to 2 at.% of Mn. Pure type I and type II twin boundaries occur in crystals with smooth chemical composition gradients. The corresponding temperature dependences of TS follow universal linear trends with the …

Tools And Strategies For The Patterning Of Bioactive Molecules And Macromolecules, Daniel J. Valles

Dissertations, Theses, and Capstone Projects

Hypersurface Photolithography (HP) is a printing method for fabricating structures and patterns composed of soft materials bound to solid surfaces and with ~1 micrometer resolution in the x, y, and z dimensions. This platform leverages benign, low intensity light to perform photochemical surface reactions with spatial and temporal control of irradiation, and, as a result, is particularly useful for patterning delicate organic and biological material. In particular, surface- initiated controlled radical polymerizations can be leveraged to create arbitrary polymer and block- copolymer brush patterns. Chapter 1 will review the advances in instrumentation architectures from our group that have made these …

Improvements To Emissive Plume And Shock Wave Diagnostics And Interpretation During Pulsed Laser Ablation Of Graphite, Timothy I. Calver

Theses and Dissertations

This dissertation covers nanosecond pulsed laser ablation of graphite for 4-5.7 J/cm² fluences with 248 nm and 532 nm lasers in 1-180 Torr helium, argon, nitrogen, air, and mixed gas. Three experiments were performed to improve the interpretation of common diagnostics used to characterize pulsed laser ablation, find simple but universal scaling relationships for comparing dynamics across different materials and ablation conditions, and provide a systematic analysis of graphite emissive plume and shock wave dynamics. A scaling of the Sedov-Taylor energy ratio was developed and validated for a range of studies despite differences in wavelength, pulse duration, fluence, and …

Molecular Dynamics Simulations Of Self-Assemblies In Nature And Nanotechnology, Phu Khanh Tang

Dissertations, Theses, and Capstone Projects

Nature usually divides complex systems into smaller building blocks specializing in a few tasks since one entity cannot achieve everything. Therefore, self-assembly is a robust tool exploited by Nature to build hierarchical systems that accomplish unique functions. The cell membrane distinguishes itself as an example of Nature’s self-assembly, defining and protecting the cell. By mimicking Nature’s designs using synthetically designed self-assemblies, researchers with advanced nanotechnological comprehension can manipulate these synthetic self-assemblies to improve many aspects of modern medicine and materials science. Understanding the competing underlying molecular interactions in self-assembly is always of interest to the academic scientific community and industry. …

Impact Behavior Of Laminated Composites Built With Fique Fibers And Epoxy Resin: A Mechanical Analysis Using Impact And Flexural Behavior, Julian Rua, Mario F. Buchely, Sergio Neves Monteiro, Gloria I. Echeverri, Henry A. Colorado

Materials Science and Engineering Faculty Research & Creative Works

This research analyzes the behavior of natural fiber reinforced laminated polymer composites (NFRPC) under mechanical solicitations. Samples were fabricated with epoxy resin matrix reinforced with a multilayer natural fique fiber in a bi-directional commercial fabric configuration. Different reinforcement contents without additives were prepared taking in the account the simplicity in processing, fabrication cost, and applications in which this material might be used with high performance standards. Charpy notched impact and 3-point bending test were carried out to evaluate the mechanical behavior and the work of fracture, which was improved significatively with the fibers, showing an increase from 5 to 30 …

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 …

Electrostatic Flocking Of Salt-Treated Microfibers And Nanofiber Yarns For Regenerative Engineering, Alec Mccarthy, Kossi Loic M. Avegnon, Phil A. Holubeck, Demi Brown, Anik Karan, Navatha Shree Sharma, Johnson V. John, Shelbie Weihs, Jazmin Ley, Jingwei Xie

Mechanical Engineering Faculty Publications

Electrostatic flocking is a textile technology that employs a Coulombic driving force to launch short fibers from a charging source towards an adhesive-covered substrate, resulting in a dense array of aligned fibers perpendicular to the substrate. However, electrostatic flocking of insulative polymeric fibers remains a challenge due to their insufficient charge accumulation. We report a facile method to flock electrostatically insulative poly(ε-caprolactone) (PCL) microfibers (MFs) and electrospun PCL nanofiber yarns (NFYs) by incorporating NaCl during pre-flock processing. Both MF and NFY were evaluated for flock functionality, mechanical properties, and biological responses. To demonstrate this platform's diverse applications, standalone flocked NFY …

Atomistic Simulation Of Desalination, Ian David Durr

Symposium of Student Scholars

Atomistic Simulation of Desalination

Ian Durr, Matheus Prates, and Jungkyu Park

Kennesaw State University

In this research, we investigate the desalination capacity of three-dimensional (3D) carbon nanostructures using molecular dynamics simulations. 3D carbon nanostructures proposed here will filter seawater efficiently because of their multiple layers with holes of tunable sizes. The structure is designed to be flexible, allowing mechanical deformation during daily use. The 3D carbon nanostructure will still possess high thermal conductivity, enabling easy recycle through a simple heating process. Here, we employ LAMMPS, Large-scale Atomic/MolecularMassively Parallel Simulator distributed by Sandia National Laboratories to measure salt ion flux through …

Feedstock Powders For Reactive Structural Materials, Daniel Hastings

Dissertations

Metals as fuels have higher energy density per unit mass or volume compared to any hydrocarbon. At the same time, metals are common structural materials. Exploring metals as reactive structural materials may combine their high energy density with attractive mechanical properties. Preparing such materials, however, is challenging. Requirements that need to be met for applications include density, strength, and stability enabling the component to sustain the structure during its desired operation; added requirements are the amount and rate of the energy release upon impact or shock. Powder technology and additive manufacturing are approaches considered for design of reactive structural materials. …

Towards Quality By Design (Qbd) Of Pharmaceutical Oral Films Loaded With Poorly Watersoluble Drugs, Eylul Cetindag

Dissertations

Oral films are an emerging drug delivery dosage form with numerous advantages such as ease of handling, the possibility to circumvent the first-pass metabolism, better patient compliance, capability for continuous manufacturing, and as a platform for personalized medicine. As films are different from other final dosages by their dimensions and their matrix form, further research is required to better understand the impact of excipient and drug on product performance to assure a consistent and good quality product. Therefore, this dissertation aims to contribute towards the processability and manufacturability of films by examining the impact of the materials and processes. First, …

Dft Study Of NiM@Pt1AuN-M-1 (N=19, 38, 55, 79; M = 1, 6, 13, 19) Core-Shell Orr Catalyst, Wen-Jie Li, Dong-Xu Tian, Hong Du, Xi-Qiang Yan

Journal of Electrochemistry

The slow kinetics of oxygen reduction reaction (ORR) limits the performance of low temperature fuel cells. Thus, it needs to design effective catalysts with low cost. Core-shell clusters (CSNCs) show promising activity because of their size-dependent geometric and electronic effects. The ORR activity trend of Ni_m@Pt₁Au_n-m-1(n = 19, 38, 55, 79; m = 1, 6, 13, 19) was studied using the GGA-PBE-PAW methods. The adsorption configurations of *O, *OH and *OOH were optimized and the reaction free energies of four proton electron (H⁺ + e^-) transfer steps …

One-Pot Synthesis Of Fe2O3@Fe-N-C Oxygen Reduction Electrocatalyst And Its Performance For Zinc-Air Battery, Hua Lin, Yi-Jin Wu, Jun-Tao Li, Yao Zhou

Journal of Electrochemistry

Oxygen reduction reaction (ORR) plays a profound role in determining cathode performance in metal-air batteries and fuel cells. Owing to its inherently sluggish kinetics, high-performance ORR catalysts which favors the scissoring of O-O bond and formation of O-H bond are a requisite. In this regard, Pt has been explored as the most efficient ORR electrocatalysts. Nevertheless, due to its expensiveness, the usage of Pt catalysts represents one of the major sources of cost in those energy conversion devices. Thus, the development of alternative ORR electrocatalysts with minimized Pt utilization has been widely pursued over the past few decades. Metal-nitrogen-carbon catalysts …