Engineering Commons^™

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 …

Seizure Detection Using Deep Learning, Information Theoretic Measures And Factor Graphs, Bahareh Salafian

Electronic Thesis and Dissertation Repository

Epilepsy is a common neurological disorder that disrupts normal electrical activity in the brain causing severe impact on patients’ daily lives. Accurate seizure detection based on long-term time-series electroencephalogram (EEG) signals has gained vital importance for epileptic seizure diagnosis. However, visual analysis of these recordings is a time-consuming task for neurologists. Therefore, the purpose of this thesis is to propose an automatic hybrid model-based /data-driven algorithm that exploits inter-channel and temporal correlations. Hence, we use mutual information (MI) estimator to compute correlation between EEG channels as spatial features and employ a carefully designed 1D convolutional neural network (CNN) to extract …

Dreams Of Molecular Beams: Indium Gallium Arsenide Tensile-Strained Quantum Dots And Advances Towards Dynamic Quantum Dots (Moleculare Radiorum Somnia: Indii Gallii Arsenicus Tensa Quanta Puncta Et Ad Dinamicae Quantae Puntae Progressus), Kevin Daniel Vallejo

Boise State University Theses and Dissertations

Through the operation of a molecular beam epitaxy (MBE) machine, I worked on developing the homoepitaxy of high quality InAs with a (111)A crystallographic orientation. By tuning substrate temperature, we obtained a transition from a 2D island growth mode to step- ow growth. Optimized MBE parameters (substrate temperature = 500 °C, growth rate = 0.12 ML/s and V/III ratio ⩾ 40) lead to growth of extremely smooth InAs(111)A films, free from hillocks and other 3D surface imperfections. We see a correlation between InAs surface smoothness and optical quality, as measured by photoluminescence spectroscopy. This work establishes InAs(111)A as a platform …

Thermometry Via Diffusion In Ferrous Core-Shell Nanoparticles For Induction Heating Applications, Hayden Carlton

Graduate Theses and Dissertations

Induction heating causes the release of enormous amounts of heat from dispersed magnetic nanoparticles. While the rate of heat transfer can be easily quantified calorimetrically, measuring the temperature of the nanoparticles on the nanoscale presents experimental challenges. Fully characterizing the temperature and thermal output of these magnetic particles is necessary to gauge overall heating efficiency and to provide a more holistic understanding of heat transfer on the nanoscale. Herein, this dissertation seeks to develop a novel nanoparticle thermometry technique, which correlates diffusion behavior in core-shell nanoparticles to local temperature. Initial measurements suggested that heating silica capped ferrous nanoparticles (SCNPs) via …

Silver Microparticle And Submicron Wire - Polylactic Acid Composites For Additive Manufacturing, Jenna W. Robichaux

University of New Orleans Theses and Dissertations

This thesis explores the incorporation of silver microparticle and submicron wire additives into thermoplastic filament feedstock for fused filament fabrication (FFF) to create multifunctional three-dimensional (3D) printable composites. The impact of silver microparticle and submicron wire additives on mechanical behavior along with antibacterial effect of the silver microparticle and submicron wire additives on printed objects were assessed.

Composite FFF filaments were fabricated by solution processing, granulation, and extrusion. Differential Scanning Calorimetry (DSC) was conducted to measure the glass transition and melting point temperatures of the composite filaments for 3D printing. The effect of the additive addition on the thermal properties …

Incorporation Of Zinc In Pre-Alloyed Cuin[Zn]S2/Zns Quantum Dots, Jean Carlos Morales Orocu

Graduate Theses and Dissertations

Since the early 2000s heavy-metal-free quantum dots (QDs) such as CuInS2/ZnS have attempted to replace CdSe, their heavy-metal-containing counterparts. CuInS2/ZnS is synthesized in a two-step process that involves the fabrication of CuInS2 (CIS) nanocrystals (NCs) followed by the addition of zinc precursors. Instead of the usual core/shell architecture often exhibited by binary QDs, coating CIS QDs results in alloyed and/or partially alloyed cation-exchange (CATEX) QDs. The effect that zinc has on the properties of CIS NCs was studied by incorporating zinc during the first step of the synthesis. Different In:Cu:Zn ratios were employed in this study, maintaining a constant 4:1 …

Synthesis Of Polyethylene Glycol-Based Hydrogels And Silver/Gold Nanostructures For Biomedical Applications, Isabelle Ishimwe Niyonshuti

Graduate Theses and Dissertations

This work focuses on the synthesis of biocompatible polyethylene glycol (PEG)-based hydrogels, silver nanoparticles (AgNPs), and silver-gold nanocages (Ag-AuNCs) for biomedical applications. The dissertation includes two parts with Part I on the work of PEG-based hydrogel for wound healing applications and Part II on the work of Ag/Au nanostructures for antimicrobial applications. Part I studies PEG-based hydrogel for the delivery of fibroblast growth factors (FGFs) for wound healing applications, aiming to overcome the challenge of designing hydrogels capable of the sustained release of bioactive FGFs. This research develops new biocompatible anionic injectable hydrogel formulations based on Poly (Oligo Ethylene Glycol …

Study Of Thick Indium Gallium Nitride Graded Structures For Future Solar Cell Applications, Manal Abdullah Aldawsari

Graduate Theses and Dissertations

Indium gallium nitride (InxGa1-xN) materials have held great potential for the optoelectronic industry due to their electrical and optical properties. The tunable band gap that can span the solar spectrum was one of the most significant features that attracted researchers’ attention. The band gap can be varied continuously from 0.77 eV for InN to 3.42 eV for GaN, covering the solar spectrum from near infrared to near ultraviolet. Additionally, it has a high absorption coefficient on the order of ∼105 cm−1, a direct band gap, high radiation resistance, thermal stability, and so on. Nevertheless, the epitaxial growth of high quality …

Reliability Characterization Of A Low-K Dielectric Using Its Magnetoresistance As A Diagnostic Tool, Philip Alister Williams

Legacy Theses & Dissertations (2009 - 2024)

The introduction of low dielectric constant materials within the integrated circuit (IC) chip technology industry was a concerted effort to decrease the resistance-capacitance (RC) time delay inherent within the dielectric materials used as insulators. This stems from a demand for greater device density per IC chip and decreased feature sizes but is fast becoming a reliability issue. Concomitant with the demand for decreased feature sizes, also in adherence with Moore’s Law (which states that the number of devices on a die doubles every two years), is a reduction in device speed and performance due to device intra-level interconnection signal delays. …

Multifunctional Programmable Self-Assembled Nanoparticles In Nanomedicine, Yoshie Sakamaki

Graduate Theses and Dissertations

Developing methodologies to control the architecture of nanoparticles (NPs) at the atomic level prevents their inhomogeneity and leads to a variety of expected functions. Rationally designed nanoparticles can either be programmed or crystallized structures into pre-determined structures achieving tunable particle pore size and physiochemistry. In this dissertation, two broad classes of multifunctional nanoparticles are developed, metal-organic frameworks and DNA-NP aggregates.

Metal-organic frameworks are a novel class of highly porous crystalline materials built from organic linkers and metal cluster-based secondary building units. However, applications in bioremediation have not been developed very well especially in applications regarding drug delivery systems (DDS). The …

Recombinant Production And Purification Of Green Fluorescent Protein (Gfp)-Fused Metal Binding Protein For Palladium Nanoparticle Synthesis, Shadrach Ibinola

Graduate Theses and Dissertations

In lieu of chemical and physical methods, biologically guided synthesis is increasingly used as a cost-effective medium for the fabrication of nanoparticles (NP). Recently, a palladium metal binding sequence Pd4 (TSNAVHPTLRHL) has been demonstrated to be instrumental in the production of palladium (Pd) nanoparticles. Although, by eliminating the additional cost of purification of the protein, the crude lysate of E. coli containing Pd specific protein has been proven to be a viable cost-effective means for the synthesis of Pd NP, studies have not be done to ascertain the comparative catalytic activity of nanoparticles synthesized from both clarified lysate and pure …

Investigation Of Control Parameters, Strategies, And Transport Modeling For Effective Electrokinetic Nanoparticle Treatment Of Cementitious Materials, Huayuan Zhong

Doctoral Dissertations

Various deleterious chemical species (including sulfates, chlorides, and others) contaminate concrete structures which are inherently porous and thus suffer from compromised durability. Several technologies have been developed for repairing concrete or enhancing the service life. Nevertheless, their efficiency, practicability, and cost can vary widely. Compared with chemical grout, fiber wrap, and traditional repair technology, electrokinetic nanoparticle treatment (EN) has been found to provide remarkable benefits for strength restoration and mitigation of durability problems via porosity reduction. Nanoparticle instability and over dosage issues can arise and lead to problems during treatments. In many cases, these treatment processes have been accompanied by …

The Profound Photophysical Effects Of Organic Chromophore Connectivity And Coupling, David J. Walwark Jr

Nanoscience and Microsystems ETDs

Through-bond and through-space interactions between chromophores are shown to have wide-ranging effects on photophysical outcomes upon light absorption in organic molecules. In collapsed poly(3-hexylthiophene), through-space coupling creates hybrid chromophores that act as energy sinks for nearby excitons and favorable sites for molecular oxygen to dock. Upon excitation with visible light the highly-coupled chromophores react with the docked oxygen and subsequently do not quench nearby excitons as efficiently. In tetramer arrays of perylene diimide chromophores the central moiety through-bond connectivity is synthesized in two variants which exhibit vastly different single-molecule blinking behavior and theoretically-predicted electronic transition character. In the more-connected tetramer …

Silica Sol-Gel Control With High Voltage Contactless Electrodes, Jonathan C. Hebert

Nanoscience and Microsystems ETDs

High Voltage Contactless Electrodes (HVE) non-evasively modulates silica sol-gel reactions by redistributing charge in solution. HVE induces formation of local neutral band (LNB) strata (pseudo interfacial surfaces) where the gradient of potential is zero ∇𝜓𝜓=0. HVE LNB shape corresponds to solubility and ultimately sol-gel form. HVE silica sol-gel control works by localizing pH and creating conditions where silanol polymerization is biform; condensation by protonation (cathodic), or by deprotonation (anodic). Steric modified Poisson-Boltzmann equation is used to develop a theory on HVE control of silica sol-gel formation and a nucleate potential functional of potential 𝜓𝜓. Technologies developed during this research are …

The Physics Of Slot-Die And Gravure Coating Associated With Precision Thin Films And Coating Defects, Robert E. Malakhov

Nanoscience and Microsystems ETDs

Enabling future printable and flexible electronic (PFE) devices and technologies requires overcoming the technical challenge of manufacturing precision thin films and features at scale. Coating- and print-feature functionality for PFEs is imparted with dispersed active particulate inks that provide electronic properties via slot-die coating, a pre-metered film-deposition process, and gravure printing, a high-throughput, precision process. Both are poised to be ideal manufacturing technologies for PFEs but require further research to understand particulate effects in defect formation and processability. Therefore, overcoming the technical challenges of precision, throughput, and the complexities of particulate inks is the purpose of this work. For slot-die …

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. …

Colloidal Quantum Dot (Cqd) Based Mid-Wavelength Infrared Optoelectronics, Shihab Bin Hafiz

Dissertations

Colloidal quantum dot (CQD) photodetectors are a rapidly emerging technology with a potential to significantly impact today’s infrared sensing and imaging technologies. To date, CQD photodetector research is primarily focused on lead-chalcogenide semiconductor CQDs which have spectral response fundamentally limited by the bulk bandgap of the constituent material, confining their applications to near-infrared (NIR, 0.7-1.0 um) and short-wavelength infrared (SWIR, 1-2.5 um) spectral regions. The overall goal of this dissertation is to investigate a new generation of CQD materials and devices that advances the current CQD photodetector research toward the technologically important thermal infrared region of 3-5 ?m, known as …

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. …

Design And Development Of 2d Functional Semiconductor Nanocrystals, Andrew Hunter Davis

Dissertations - ALL

Anisotropic nanocrystals (NCs) have become of keen interest in recent years, especially for applications in optoelectronic devices due to their directionally oriented emissions, narrow emission spectra, and suitable morphologies for device integration. Of the desired anisotropic NCs, two-dimensional (2D) NCs are of profound interest, due to their impressive optical and electronic properties as well as their prospective advantages towards applications in layered optoelectronic devices, such as solar cells. However, 2D NCs face many challenges, including limited synthetic derivation, as well as decreased stability and optical response, due to their large surface-to-volume ratio and reactive planar surface increasing surface defect state …

Inherently Porous Atomically Thin Membranes For Gas Separation, Harpreet Atwal

Electronic Thesis and Dissertation Repository

Membranes made from atomically thin materials promise hundreds of times higher production rates than conventional polymer membranes for separation applications. Graphene is impermeable to gases but becomes selectively permeable once pores are introduced into it but creating trillions of nanopores over large areas is difficult. By instead choosing an inherently porous two-dimensional material with naturally identical pores repeated at high density, we may circumvent this challenge. In this work, we explore the potential of two candidate materials, 2D polyphenylene and graphdiyne. We synthesize cyclohexane-m-phenylene, a monomer of 2D polyphenylene. We then develop an atomic force microscopy technique for measuring the …

Disentangling Glial Diversity In Peripheral Nerves At Single Nuclei Resolution, Aldrin Kay Yuen Yim

Arts & Sciences Electronic Theses and Dissertations

The ability to discern gene expression at single cell level is revolutionizing our understanding of both basic biology and human health. Peripheral nerves are essential communicators between the outside world and the CNS, as evidenced by the devastating effects of diseases that disrupt them, such as ALS, Charcot-Marie-Tooth Syndrome and diabetic neuropathy. Understanding peripheral nerve dysfunction at a mechanistic level is of considerable interest due to the increasing prevalence and associated patient care costs of these disorders. Although most research of the peripheral nerve has focused on glial-axonal interactions, the important contributions of other cell types besides Schwann cells, such …

Rational Design Of Highly Efficient Electrocatalysts Using Atomic Layer Deposition: From Nanoparticle To Single Atom, Junjie Li

Electronic Thesis and Dissertation Repository

Polymer electrolyte membrane fuel cells (PEMFCs) have been attracted significant attention due to their high energy efficiency. The electrocatalyst is one of the most important parts. However, state-of-the-art electrocatalysts suffer from several challenges, including 1) low stability under harsh working conditions; 2) low atomic utilization efficiency, especially for noble metals. This thesis, therefore, focuses on the design of highly efficient and stable electrocatalysts from nanoparticles down to single atoms using atomic layer deposition (ALD) and further understand the insight mechanisms.

Firstly, Pt nanoparticles are selectively deposited on the TiO₂ modified N-doped carbon nanotubes. The strong metal-support interactions between Pt …

Transport, Photoluminescence & Photoconduction Characteristics Of Free Standing Two-Dimensional Γ-Alumina & Titanium Superlattice Doped Two-Dimensional Γ-Alumina Grown By Graphene-Assisted Atomic Layer Deposition, Elaheh Kheirandish

Theses and Dissertations

This study presents a facile high-yield bottom-up fabrication, morphology, crystallographic and optoelectronic characterization of free-standing quasi-2D γ-alumina, a non van der Waals 2D material. The synthesis comprises a multi-cycle atomic layer deposition (ALD) of amorphous alumina on a porous interconnected graphene foam as a growth scaffold and removed next by annealing and sintering the alumina/graphene/alumina sandwich at ~ 800 °C in air . The crystallographic and structural characteristics of the formed non-van der Waals quasi 2D γ-alumina were studied by X-ray diffraction (XRD), selected area electron diffraction (SAED), and high-resolution transmission electron microscopy (HRTEM). This analysis revealed the synthesized 2D …

Converting Parylene C Into A Thin Film Piezoelectric Material, Murali Manohar Duggina

Nanoscience and Microsystems ETDs

Thin-film piezoelectric materials are increasing in demand, but most materials are stiff ceramic materials. Polyvinylidene fluoride (PVDF) is a common polymer piezoelectric material, but it has limitations such as it requires post-processing steps to promote appropriate β-phase and it has a low operating and Curie Temperature, which limits its use in traditional microfabrication processing. The toxicity of PZT makes it incompatible with biomedical applications. Therefore, there is a need to develop a new class of polymer piezoelectric films that are compatible with current microfabrication methods. Parylene C (PA-C) is a chemical vapor deposited semi-crystalline polymer material with a nonsymmetric polymer …

Study On Graphene-Based Nanocomposites With Special Magnetoresistance Properties, Songlin Yang

Electronic Thesis and Dissertation Repository

Magnetoresistance (MR) refers to the change of a material’s electrical resistance under the presence of an external magnetic field. The discovery of new MR phenomena (e.g., giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR)) since the 1980s initiates the revolution of novel electric devices in the fields of data storage, position sensing, current sensing, non-destructive monitoring, biomedical sensing systems, etc. However, current devices display inadequate MR at the low magnetic field/room temperature, limited working range, and bulky size, which hinders the further application of MR sensors/devices. Therefore, the main goal of this thesis is to develop two-dimensional MR materials with …

Simulation Of Light Propagation Captured By Photoemission Electron Microscopy (Peem), Nabila Islam

Dissertations and Theses

The Photoemission electron microscopes (PEEM) is a powerful tool capable of synchronously imaging wave nature of light manifested by interference patterns as well as its particle nature through the energy exchange between the incident photons and the photoemitted imaging electrons. PEEM offers a non-invasive high-resolution approach for studying light propagation and interaction phenomena within a nanophotonic waveguide [7,8]. The electric field intensity variation of the interference pattern yielded by the interaction between the incident light and the guided mode coupled into the waveguide produces varying photoemission yields creating contrast in PEEM image. The guided modes cannot be excited simply by …

Thermoelectric Transport In Disordered Organic And Inorganic Semiconductors, Meenakshi Upadhyaya

Doctoral Dissertations

The need for alternative energy sources has led to extensive research on optimizing the conversion efficiency of thermoelectric (TE) materials. TE efficiency is governed by figure-of-merit (ZT) and it has been an enormously challenging task to increase ZT > 1 despite decades of research due to the interdependence of material properties. Most doped inorganic semiconductors have a high electrical conductivity and moderate Seebeck coefficient, but ZT is still limited by their high lattice thermal conductivity. One approach to address this problem is to decrease thermal conductivity by means of alloying and nanostructuring, another is to consider materials with an inherently low …

The Impact Of Nanopulse Treatment On The Tumor Microenvironment In Breast Cancer: Overturning The Treg Immunosuppressive Dominance, Anthony Nanajian

Biomedical Sciences Theses & Dissertations

Nanopulse treatment (NPT) is a high-power electric engineering modality that has been shown to be an effective local tumor treatment approach in multiple cancer models. Our previous studies on the orthotopic 4T1-luc breast cancer model demonstrated that NPT ablated local tumors. The treatment consequently conferred protection against a second live tumor challenge and minimized spontaneous metastasis. This study aims to understand how NPT mounts a potent immune response in a predominantly immunosuppressive tumor.

NPT changed the local and systemic dynamics of immunosuppressive cells by significantly reducing the numbers of regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages …

Molecular Dynamics Simulations Of Ion Transport Through Electrically Stressed Biological Membranes, Federica Castellani

Biomedical Engineering Theses & Dissertations

The cell membrane is a selectively permeable barrier that controls the transport of ions, molecules, and other materials into and out of a cell. The manipulation of the cell membrane permeability is the basis for several biotechnological and biomedical applications, including electroporation. Electroporation (or electropermeabilization) occurs when the application of an external electric pulse causes water intrusion into the membrane interior and the formation of conductive transmembrane electropores. These electropores allow drugs, genetic material, and other normally impermeant molecules to enter a cell. Despite years of study, the complex mechanisms underlying this process are still not well understood. Molecular dynamics …

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 …