Materials Science and Engineering Commons^™

Design, Manufacture, And Structural Dynamic Analysis Of A Biomimetic Insect-Sized Wing For Micro Air Vehicles, Jose Enrique Rubio

University of New Orleans Theses and Dissertations

The exceptional flying characteristics of airborne insects motivates the design of biomimetic wing structures that can exhibit a similar structural dynamic behavior. For this purpose, this investigation describes a method for both manufacturing a biomimetic insect-sized wing using the photolithography technique and analyzing its structural dynamic response. The geometry of a crane fly forewing (family Tipulidae) is acquired using a micro-computed tomography scanner. A computer-aided design model is generated from the measurements of the reconstructed scanned model of the insect wing to design the photomasks of the membrane and the venation network required for the photolithography procedure. A composite …

Adaption Of Catechol And Reversible Addition-Fragmentation Chain-Transfer (Raft) Chemistries For Water-Based Applications, Olabode Oyeneye

Electronic Thesis and Dissertation Repository

Incorporating the binding chemistry of catechol functionality with RAFT chemistry offers a facile and simplified approach for developing a suite of new 2D and 3D hybrid materials with tailored morphologies. Leveraging both chemistries by synthesizing catechol-end functionalized RAFT agents and catechol-containing monomeric species for RAFT (co)polymerization, this dissertation examined a new series of advanced materials that were designed for water-based applications including model flocculants, thermoresponsive hydrogels, adsorbents and underwater adhesives.

To prepare the RAFT agents, novel trithiocarbonates with several catechol end R groups (as postpolymerization anchors) were synthesized that differ in their carbonyl α-substituents (Dopa-CTAs). These materials were evaluated for …

Spray-Dried Cellulose Nanofibril-Reinforced Polypropylene Composites For Extrusion-Based Additive Manufacturing, Lu Wang

Electronic Theses and Dissertations

Compared to conventional manufacturing process, additive manufacturing (AM) offers free-form design, lighter and more ergonomic products, short lead time and less waste. Extrusion-based AM can be used to print thermoplastics. However, extrusion-based AM has processing challenges in printing semi-crystalline thermoplastics, for instance, polypropylene (PP). Cellulose nanofibrils (CNF) are one type of cellulose nanofibers that are produced from pulp fibers. CNF has extraordinary properties which make it an ideal candidate to reinforce polymers. Spray-dried CNF (SDCNF) is able to be incorporated into thermoplastic matrices without modifying conventional processing procedures.

The mechanical properties of 3D printed plastic parts have been considered significantly …

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of …

Transport Of Water And Ions Through Single-Walled Armchair Carbon Nanotubes: A Molecular Dynamics Study, Michelle Patricia Aranha

Doctoral Dissertations

The narrow hydrophobic interior of a carbon nanotube (CNT) poses a barrier to the transport of water and ions, and yet, unexpectedly, numerous experimental and simulation studies have confirmed fast water transport rates comparable to those seen in biological aquaporin channels. These outstanding features of high water permeability and high solute rejection of even dissolved ions that would typically require a lot of energy for separation in commercial processes makes carbon nanotubes an exciting candidate for desalination membranes. Extending ion exclusion beyond simple mechanical sieving by the inclusion of electrostatics via added functionality to the nanotube bears promise to not …

Fabrication And Characterization Of Hybrid Nanocomposites By Matrix Assisted Pulsed Laser Evaporation, Songlin Yang

Electronic Thesis and Dissertation Repository

Different methods have been applied to deposit hybrid nanocomposites which can be applied in various fields due to their light weight and multifunctional properties. Here, matrix assisted pulsed laser evaporation (MAPLE) equipment with 532 nm Nd:YAG laser is applied to fabricate three types of hybrid nanocomposites on different substrates.

Chemical synthesized FeCo nanoparticles were deposited on graphene sheets by MAPLE technique (laser fluence: 300 mJ/cm²). The effects of deposition time (t) on particle amount, shape and size have been investigated. Yttrium barium copper oxide (YBCO) materials are one type of high-temperature superconductive materials and …

Cellulose Reinforced Thermoplastic Composites By In-Situ Ring-Opening Polymerization, Shahab Kashani Rahimi

Dissertations

Over the past two decades, the increasing concern about the negative environmental impacts of synthetic materials has led to rising interests in utilizing renewable natural resources to develop polymer materials with comparable properties and performance to their synthetic counterparts. One of the major fields of interest is polymer composites where the replacement of synthetic fibers with bio renewable natural fibers is of great potential. However, the processing difficulties, in terms of fiber dispersion and thermal stability have limited the application of cellulosic fibers to polymers with low processing temperatures which are mostly hydrophobic polymers. As a result, the true reinforcing …

Study Of Iron Ion Transit Through Three-Fold Channel Of Ferritin Cage, Shah Alam Limon

MSU Graduate Theses

Ferritin is an iron-storage globular protein with an ability to uptake, mineralize and release iron ions in a controllable manner. The globular hollow shell allows storage of mineralized iron, with several channels responsible for the transit of ions into the shell and out of it. Understanding of the detailed molecular functioning of ferritin is required for rational design of biomimetic conjugate nano-biosystems containing ferritin-like constituents. In this work, ferritin was investigated both numerically by all-atom molecular dynamics (MD) simulations, and experimentally by Raman spectroscopy. Molecular dynamic simulations of a model system comprising iron ions (Fe2+) and a ferritin trimer expressing …

Liquid Gating Ptfe Membranes To Reduce Fouling, Jonathan C. Overton

Electronic Theses and Dissertations

In the processing industry, fouling due to the accumulation of bioparticles or bacteria on the surface of membranes results in decreased capacity, and subsequently requires filtration membranes to require periodic cleaning, causing increased operating costs. In this work, we evaluate the recently discovered concept of liquid-gated membranes (LGMs) in both filtration characteristics, as well as their ability to facilitate passive cleaning of membranes fouled with whey proteins. Additionally, we show that biofilms formed on the surface of these membranes can be removed through exposure to an air-water interface through a simple dipping step. We further analyze the mechanisms of fouling …

End-Capping Star-Like Polycaprolactone With Different Functional Groups And The Interaction With Smooth Muscle Cells, Qingya Zeng

Masters Theses

Polycaprolactone (PCL) is a PDA-approved biodegradable polymer with excellent biocompatibility and flexibility. My work has been designed to find out how different functional end groups in star-like PCL samples affect the surface properties (such as hydrophilicity, morphology) and bulk properties (such as thermal, mechanical, rheological properties, and crystallization), and consequently the behavior and functions of primary rat aortic smooth muscle cells (SMCs).

I focused on the synthesis of PCL with different functional groups and their characterizations. In chapter 2, PCL samples with four or six hydroxyl end groups were synthesized with different molecular weights ranging from 8,000 to 30,000 g/mol …

The Effect Of Biocomposite Material In A Composite Structure Under Compression Loading, Benjamin Andrew Sweeney

Master's Theses

While composite structures exhibit exceptional strength and weight saving possibilities for engineering applications, sometimes their overall cost and/or material performance can limit their usage when compared to conventional structural materials. Meanwhile ‘biocomposites’, composite structures consisting of natural fibers (i.e. bamboo fibers), display higher cost efficiency and unique structural benefits such as ‘sustainability’. This analysis will determine if the integration of these two different types of composites are beneficial to the overall structure. Specifically, the structure will consist of a one internal bamboo veneer biocomposite ply; and two external carbon fiber weave composite plies surrounding the bamboo biocomposite. To acquire results …

Structural Characteristics And Corrosion Behavior Of Bio-Degradable Zn-Li Alloys In Stent Application, Shan Zhao

Dissertations, Master's Theses and Master's Reports

Zinc has begun to be studied as a bio-degradable material in recent years due to its excellent corrosion rate and optimal biocompatibility. Unfortunately, pure Zn’s intrinsic ultimate tensile strength (UTS; below 120 MPa) is lower than the benchmark (about 300 MPa) for cardiovascular stent materials, raising concerns about sufficient strength to support the blood vessel. Thus, modifying pure Zn to improve its mechanical properties is an important research topic.

In this dissertation project, a new Zn-Li alloy has been developed to retain the outstanding corrosion behavior from Zn while improving the mechanical characteristics and uniform biodegradation once it is implanted …

Tunable Nanocomposite Membranes For Water Remediation And Separations, Sebastián Hernández Sierra

Theses and Dissertations--Chemical and Materials Engineering

Nano-structured material fabrication using functionalized membranes with polyelectrolytes is a promising research field for water pollution, catalytic and mining applications. These responsive polymers react to external stimuli like temperature, pH, radiation, ionic strength or chemical composition. Such nanomaterials provide novel hybrid properties and can also be self-supported in addition to the membranes.

Polyelectrolytes (as hydrogels) have pH responsiveness. The hydrogel moieties gain or lose protons based on the pH, displaying swelling properties. These responsive materials can be exploited to synthesize metal nanoparticles in situ using their functional groups, or to immobilize other polyelectrolytes and biomolecules. Due to their properties, these …

Design Of Robust Hydrogel Based On Mussel-Inspired Chemistry, Yuan Liu

Dissertations, Master's Theses and Master's Reports

The structure of catechol is found in mussel adhesive proteins and contributed to both wet-resistant adhesion and cohesive curing of these proteins. A synthetic nano-silicate, Laponite was incorporated into catechol-containing hydrogels and the hydrogel network-bound catechol formed strong reversible interfacial interaction with Laponite. The contribution of incorporated catechol-Laponite reversible interfacial interactions to the mechanics of hydrogels constructed by different strategies was studied. In the first strategy, Laponite and catechol were introduced into the double network hydrogel (DN) via the free radical co-polymerization of a catechol-containing monomer, backbone monomer, and crosslinker. The introduction of catechol-Laponite interactions significantly improved the compressive strength …

Study Of Nano-Bio Interfaces In Nano-Bio Conjugates: Nanoparticles Of Zinc Oxide (Zno) And Biomolecules Of Glucose, Cytosine, And Thymine, Bithi Paul

MSU Graduate Theses

Nano conjugates, composites of inorganic nanomaterials and bio molecules such as DNA, RNA and proteins, establish a sequence of wide varieties of nano-bio boundaries. The formation of these boundaries strongly depends on bio physicochemical reaction of biomolecules coated on the surface of nanomaterials. I am investigating various nano-bio conjugates consisting of zinc oxide (ZnO) nanoparticles with simple biomolecules including glucose and the nitrogenous bases of DNA such as cytosine and thymine. All nano-bio conjugates were fabricated using a standard bio-chemical synthesis process. Structural, physical, bio-chemical interface properties of nano-bio composites were probed using X-ray diffraction (XRD), Raman spectroscopy, and photoluminescence …

Fabrication Of Flexible, Biofunctional Architectures From Silk Proteins, Ramendra K. Pal

Theses and Dissertations

Advances in the biomedical field require functional materials and processes that can lead to devices that are biocompatible, and biodegradable while maintaining high performance and mechanical conformability. In this context, a current shift in focus is towards natural polymers as not only the structural but also functional components of such devices. This poses material-specific functionalization and fabrication related questions in the design and fabrication of such systems. Silk protein biopolymers from the silkworm show tremendous promise in this regard due to intrinsic properties: mechanical performance, optical transparency, biocompatibility, biodegradability, processability, and the ability to entrap and stabilize biomolecules. The unique …

A 3d Biomimetic Scaffold Using Electrospinning For Tissue Engineering Applications, Samerender Nagam Hanumantharao

Dissertations, Master's Theses and Master's Reports

Electrospinning holds great promise for designing functional 3D biomimetic scaffolds for tissue engineering applications. The technique allows for the reproducible fabrication of 3D scaffolds with control over the porosity and thickness. In this work, a novel method for the synthesis of a 3D electroactive scaffold using electrospinning from polycaprolactone (PCL), Polyvinylidene Fluoride (PVDF) and Polyaniline (PANI) is reported. Additional scaffolds involving different morphologies of PCL, PCL-PVDF and PCL-PANI-PVDF were also fabricated and evaluated. The scaffolds were characterized using electron microscopy to visualize the morphologies. Infrared spectroscopy was used to confirm the presence of polymers and their respective phases in the …

Electrospinning Novel Aligned Polymer Fiber Structures For Use In Neural Tissue Engineering, Rachel Martin

Dissertations, Master's Theses and Master's Reports

A suitable tissue scaffold to support and assist in the repair of damaged tissues or cells is important for success in clinical trials and for injury recovery. Electrospinning can create a variety of polymer nanofibers and microfibers, and is being widely used to produce experimental tissue scaffolds for neural applications. This dissertation examines various approaches by which electrospinning is being used for neural tissue engineering applications for the repair of injuries to the central nervous system (CNS) and the peripheral nervous system (PNS). Due to the poor regeneration of neural tissues in the event of injury, tissue scaffolds are being …

Bio Inspired Lightweight Composite Material Design For 3d Printing, Kaushik Thiyagarajan

Electronic Theses and Dissertations

Lightweight material design is an indispensable subject in product design. The lightweight material design has high strength to weight ratio which becomes a huge attraction and an area of exploration for the researchers as its application is wide and increasing even in every day-to-day product. Lightweight composite material design is achieved by selection of the cellular structure and its optimization. Cellular structure is used as it has wide multifunctional properties in addition to the lightweight characteristics. Applications of light weight cellular structures are wide and is witnessed in all industries from aerospace to automotive, construction to product design. In this …