Engineering Commons^™

Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi

Chemistry & Biochemistry Faculty Publications

We investigate switching of photoluminescence (PL) from PbS quantum dots (QDs) crosslinked with two different types of photochromic diarylethene molecules, 4,4'-(1-cyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (1H) and 4,4'-(1-perfluorocyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (2F). Our results show that the QDs crosslinked with the hydrogenated molecule (1H) exhibit a greater amount of switching in photoluminescence intensity compared to QDs crosslinked with the fluorinated molecule (2F). With a combination of differential pulse voltammetry and density functional theory, we attribute the different amount of PL switching to the different energy levels between 1H and 2F molecules which result in different potential barrier …

Inverse Engineering Of Absorption And Scattering In Nanoparticles: A Machine Learning Approach, Alex Vallone, Nooshin M. Estakhri, Nasim Mohammadi Estrakhri

Engineering Faculty Articles and Research

We use a region-specified machine learning approach to inverse design highly absorptive multilayer plasmonic nanoparticles. We demonstrate the design of particles with a wide range of absorption to scattering ratios (i.e., cloaked absorbers and bright absorbers) and for different visible wavelengths.

Magnetic Softness Tuned Superparamagnetic Nanoparticles For Highly Efficient Cancer Theranostics, Jie Wang

Theses and Dissertations

Magnetic resonance imaging (MRI)-guided magnetic nanofluid hyperthermia (MNFH) using iron oxide based superparamagnetic nanoparticles (SPNPs) has recently attracted considerable attention as a treatment modality for cancer theranostics, because MRI-guided MNFH can allow for diagnosis, therapeutics, and prognosis simultaneously using the same administrated magnetic nanofluid agent. However, several primary limiting factors: (1) insufficient AC magnetic heating induction (specific loss power/intrinsic loss power, SLP/ILP) at the biologically safe and physically tolerable range of AC magnetic field (H_AC,safe: f_appl × H_appl < 3.0 ~ 5.0×10⁹ A·m^-1·s^-1), (2) low _r2- relaxivity directly related to the low resolution of …

Computational Design Of Fiber-Optic Probes For Biosensing, Suwarna Karna

Electrical Engineering Theses

This thesis presents a study on the optical characteristics of hollow-core photonic crystal fibers (HC-PCFs) with a band gap cladding structure and their applications in optical fiber sensing. This 800B HC-PCF exhibited excellent optical properties and has a flexible structure, which makes them suitable for a wide range of industrial applications. Finite element simulations and structural optimization designs were conducted using the surface plasmon resonance (SPR) technique to determine the optimal performance parameters of the 800B HC-PCF. The fiber was further modified using the SPR technique to improve its practical detection capabilities. The performance of the modified fiber was observed …

Ultrasensitive Tapered Optical Fiber Refractive Index, Erem Ujah, Meimei Lai, Gymama Slaughter

Electrical & Computer Engineering Faculty Publications

Refractive index (RI) sensors are of great interest for label-free optical biosensing. A tapered optical fiber (TOF) RI sensor with micron-sized waist diameters can dramatically enhance sensor sensitivity by reducing the mode volume over a long distance. Here, a simple and fast method is used to fabricate highly sensitive refractive index sensors based on localized surface plasmon resonance (LSPR). Two TOFs (l = 5 mm) with waist diameters of 5 µm and 12 µm demonstrated sensitivity enhancement at λ = 1559 nm for glucose sensing (5-45 wt%) at room temperature. The optical power transmission decreased with increasing glucose concentration due …

Using Molecular Dynamics Simulations To Decipher Mechanistic Details Of Biomolecular Processes Of Biology And Biotechnology Oriented Applications, Adithya Polasa

Graduate Theses and Dissertations

Researchers in chemistry and biology often utilize computer simulations, in conjunction with experimental data, to model and predict the structures, energies, kinetics, processes, and functions of the systems that are their focus of study, ranging from single molecules to whole viruses. Here, we use molecular dynamics (MD) techniques to gain a deeper understanding of biomolecular processes in biology and biotechnology-oriented applications. Using a mixture of equilibrium and non-equilibrium MD simulations, this work describes the insertion process of YidC at the atomic level. In order to better comprehend the insertion process, several docking models of YidC-Pf3 in the lipid bilayer were …

Passive Cooling Analysis Of An Electronic Chipset Using Nanoparticles And Metal-Foam Composite Pcm: An Experimental Study, Faisal Hassan, Abid Hussain, Furqan Jamil, Adeel Arshad, Hafiz Muhammad Ali

Research outputs 2022 to 2026

Thermal management of electronic components is critical for long-term reliability and continuous operation, as the over-heating of electronic equipment leads to decrement in performance. The novelty of the current experimental study is to investigate the passive cooling of electronic equipment, by using nano-enriched phase change material (NEPCM) with copper foam having porosity of 97 %. The phase change material of PT-58 was used with graphene nanoplatelets (GNPs) and magnesium oxide (MgO) nanoparticles (NPs), having concentrations of 0.01 wt. % and 0.02 wt. %. Three power levels of 8 W, 16 W, and 24 W, with corresponding heating inputs of 0.77 …

Laser-Induced Galfenol Embedded Multi-Layer Graphene-Oxide In Solution, Devyn Duryea, Nirmala Kandadai

Electrical and Computer Engineering Faculty Publications and Presentations

The proposed work demonstrates the direct synthesis of nanomaterial-embedded laser-induced few-layer graphene-oxide by directly ablating galfenol in a water-based solution for the first time. Laser-induced multilayer graphene-oxide (GO) embedded with galfenol (gallium–iron alloy) nanoparticles (NPs) is created through a method of direct laser inscription of bulk galfenol in deionized (DI) water with femtosecond laser ablation. The NP-embedded GO is achieved by irradiating a near-infrared (near-IR) femtosecond laser at 1040 nm on a bulk galfenol material submerged in a solution comprising DI water and a small concentration (5%/wt.) of polyvinylpyrrolidone followed by a second ablation in pure DI water. Results show …

Spray Deposition Of Sustainable Plant Based Graphene In Thermosetting Carbon Fiber Laminates For Mechanical, Thermal, And Electrical Properties, Daniel W. Mulqueen, Siavash Sattar, Thienan Le, Oleksandr G. Kravchenko

Mechanical & Aerospace Engineering Faculty Publications

Graphene has generated substantial interest as a filler due to its exceptional strength, flexibility, and conductivity but faces obstacles in supply and implementation. A renewable, plant-based graphene nanoparticle (pGNP) presents a more accessible filler with the same properties as mineral graphenes. In this study, we examine the effects of pGNP, which was sprayed on a carbon fiber/epoxy prepreg at loadings from 1.1 to 4.2 g/m². The study considered the mechanical, thermal, and electrical properties of pGNP-composite. An even particle dispersion was achieved using a spray application of pGNP in a water/alcohol suspension with the addition of surfactants and …

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 …

Nanoparticles For Targeted Drug Delivery To Cancer Stem Cells: A Review Of Recent Advances, Yavuz Nuri Ertas, Keyvan Abedu Dorcheh, Ali Akbari, Esmaiel Jabbari

Faculty Publications

Cancer stem cells (CSCs) are a subpopulation of cells that can initiate, self-renew, and sustain tumor growth. CSCs are responsible for tumor metastasis, recurrence, and drug resistance in cancer therapy. CSCs reside within a niche maintained by multiple unique factors in the microenvironment. These factors include hypoxia, excessive levels of angiogenesis, a change of mitochondrial activity from aerobic aspiration to aerobic glycolysis, an upregulated expression of CSC biomarkers and stem cell signaling, and an elevated synthesis of the cytochromes P450 family of enzymes responsible for drug clearance. Antibodies and ligands targeting the unique factors that maintain the niche are utilized …

Analysis Of Photodetector Based On Zinc Oxide And Cesium Lead Bromide Heterostructure With Interdigital Metallization, Tanveer Ahmed Siddique

Graduate Theses and Dissertations

In this thesis, photodetector based on the zinc oxide and cesium lead bromide hetero structure were fabricated and characterized. Zinc oxide (ZnO) nanoparticles were synthesized using solution processing and cesium lead bromide (CsPbBr3) thin film was synthesized using two step deposition method. Three phonon modes were obtained by the Raman spectroscopy of ZnO nanoparticles. X-ray diffraction spectra of ZnO exhibits five exciton peaks which denotes that the synthesized ZnO structure was of good crystallinity with wurtzite hexagonal phase. The absorbance spectrum of ZnO shows the bandgap (Eg) in the order of 3.5 eV that aligns with reported results. The photoluminescence …

Time-Domain Measurement Of Magnetization Dynamics In Ferrofluids, Brian Egenriether

Theses and Dissertations

Time-domain measurements are made on a magnetite-based (Fe3O4) ferrofluid using an inductive technique. The constituent particles are 5.8% by volume, polydisperse, and have a nominal diameter of 10nm with a ~1nm-thick anionic hydrophobic coating. The ferrofluid is placed in a sealed channel on a coplanar waveguide (CPW) situated in an adjustable external magnetic bias field. A fast-rising step current in the CPW quickly reorients the local magnetic field above the signal trace causing the particles’ moments to align in the new field configuration. This changing magnetization induces a voltage in the CPW that is detected by a sampling oscilloscope. Precessional …

Understanding The Effects Of Plasma Assisted Nanoparticle Deposition For The Enhancement Of Optical And Electrochemical Response, Apurva Sonawane

FIU Electronic Theses and Dissertations

In this work, the effects of atmospheric plasma treatment on morphology, optical, and electrochemical properties of 10 ± 3nm spherical silver and gold nanoparticles (AgNPs and AuNPs) functionalized substrates were studied. The nanoparticles (NPs) were deposited on substrates by drop-casting, aerosol spray, and a low-temperature atmospheric plasma-assisted aerosol jet. The reduction in nanoparticle size was observed, which was explained by the redox reaction that occurs on the nanoparticle surface. This phenomenon was evident by the presence of AgO, Ag₂O, and AuO_x Raman peaks in the treated sample. The surface charge changed as a result of plasma treatment, …

Cancer Biomarker Detection In Human Plasma By Integrating Surface Acoustic Wave And Metal-Enhanced Fluorescence, Yuqi Huang

USF Tampa Graduate Theses and Dissertations

This thesis includes data and discussion about the technique of metal-enhanced fluorescence (MEF) to lower the detection limit of carcinoembryonic antigen (CEA). The detection limit goes down to 100pg/mL level when using MEF substrate made by rapid thermally annealed silver film covered by silica, which has great promise in diagnosing certain types of cancer that uses CEA as detection biomarker, such as pancreatic cancer and colon cancer. To further address the issue of background noises from non-specifically bound proteins (NSB) in complex media, such as plasma, serum, urine and blood, MEF is integrated with surface acoustic wave (SAW) streaming in …

Formulation Strategies To Enhance Solubility And Permeability Of Small Molecules For Drug Delivery Applications, Pradeep Kumar Bolla

Open Access Theses & Dissertations

All the new chemical entities/drug molecules intended for therapeutic use must be administered using an appropriate delivery system/dosage form to achieve maximum bioavailability. However, designing a drug delivery system is complex as several factors such as lipophilicity, molecular mass, crystallinity, ionic charge, polymorphic forms and hydrogen bonding) affect the solubility and permeability of these molecules. Biopharmaceutics drug classification system (BCS) categorizes the existing drugs into four classes based on the aqueous solubility and membrane permeability and it is reported that >70% of the drugs are poorly soluble and belong to BCS class II and BCS class IV. Several physical, chemical …

Erratum: "Imaging The Three‐Dimensional Orientation And Rotational Mobility Of Fluorescent Emitters Using The Tri‐Spot Point Spread Function", Oumeng Zhang, Jin Lu, Tianben Ding, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

In the original paper, a calibration error exists in the image-formation model used to analyze experimental images taken by our microscope, causing a bias in the orientation measurements in Figs. 2 and 3. The updated measurements are shown in Fig. E1. We have also updated the supplementary material for the original article to discuss the revised PSF model and estimation algorithms (supplementary material 2) and show the revised model and measurements (Figs. S1, S3, S7, S8, and S10–S13).

Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji

Electrical & Computer Engineering Faculty Publications

Tungsten oxide is a versatile material with different applications. It has many polymorphs with varying performance in energy storage application. We report simple and facile way to synthesize four phases of tungsten oxide from same precursor materials only by changing the pH and temperature values. Monoclinic, hexagonal, orthorhombic and tetragonal phase obtained, were analyzed and tested for supercapacitor application. The electrochemical analysis of four phases indicates that the hexagonal phase is best-suited electrode material for supercapacitor. The hexagonal phase exhibits higher specific capacitance (377.5 Fg^-1 at 2 mVs^-1), higher surface capacitive contribution (75%), better stability and rate …

Efficiency Improvement Of Up-Conversion Process Of Plasmonic-Enhanced Er-Doped-Nayf4 Nanoparticles Under Ir Excitation, Sara Elrafei, Ishac Kandas, Nader Shehata, Effat Samir

Electrical and Computer Engineering Faculty Publications

The up-conversion process is extensively studied because of its wide variety of applications such as bioimaging, energy harvesting, and optical sensors. However, the optical conversion efficiency is still relatively low and needs to be improved. Therefore, this paper introduces a detailed study of improving the up-conversion emission efficiency through adding plasmonic metallic nanostructures to the up-conversion optical centers. Our idea is to couple the optical plasmonic resonance with the visible emission of the optical centers under IR excitation. The optical centers are erbium ions hosted by fluoride low-phonon environment. Our calculations consider most possible transitions that can occur between the …

Imaging The Three-Dimensional Orientation And Rotational Mobility Of Fluorescent Emitters Using The Tri-Spot Point Spread Function, Oumeng Zhang, Jin Lu, Tianben Ding, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Fluorescence photons emitted by single molecules contain rich information regarding their rotational motions, but adapting single-molecule localization microscopy (SMLM) to measure their orientations and rotational mobilities with high precision remains a challenge. Inspired by dipole radiation patterns, we design and implement a Tri-spot point spread function (PSF) that simultaneously measures the three-dimensional orientation and the rotational mobility of dipole-like emitters across a large field of view. We show that the orientation measurements done using the Tri-spot PSF are sufficiently accurate to correct the anisotropy-based localization bias, from 30 nm to 7 nm, in SMLM. We further characterize the emission anisotropy …

Technobiology Paradigm In Nanomedicine: Treating Cancer With Magnetoelectric Nanoparticles, Emmanuel Stimphil

FIU Electronic Theses and Dissertations

Today, cancer is the world’s deadliest disease. Despite significant progress to find a cure, especially over the last decade, with immunotherapy rapidly becoming the state of the art, major open questions remain. Each successful therapy is not only limited to a few cancers but also has relatively low specificity to target cancer cells; although cancer cells can indeed be eradicated, many normal cells are sacrificed as collateral damage. To fill this gap, we have developed a class of multiferroic nanostructures known as magnetoelectric nanoparticles (MENs) that can be used to enable externally controlled high-specificity targeted delivery and release of therapeutic …

Carbon Removal And Optoelectronic Property Tuning In Copper Arsenic Sulfide Thin Films Through Ligand Exchange And Alloying, Louis R. Schroeder, Scott Mcclary, Rakesh Agrawal

The Summer Undergraduate Research Fellowship (SURF) Symposium

Solution processed thin film solar cells are attractive alternatives to conventional energy sources due to low waste generation, flexibility in substrate choice, and scalability. The novel semiconductor Cu3AsS4 in the enargite phase has a near ideal band gap of 1.4 eV and has earth abundant constituent elements; yet single-junction solar cells have yielded low efficiencies due to a secondary carbonaceous phase present, among other issues. This carbonaceous phase may be eliminated by exchanging the carbonaceous ligands with molecular metal chalcogenides. To characterize the ligand exchanged particles, UV-Vis-NIR spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and …

Magnetoelectric Nanoparticles: Paradigm Shift In Biomolecular Diagnostics, Chooda Mani Khanal

FIU Electronic Theses and Dissertations

Recently discovered multiferroic nanoparticles (MFNs) known as magnetoelectric nanoparticles (MENs) promise to revolutionize next-generation biomedical diagnostic techniques and enable rapid and cost-effective screening of lethal diseases. Due to the quantum-mechanically caused intrinsic magnetoelectric (ME) effect, these nanoparticles display strongly coupled magnetic and electric moments and thus provide a unique pathway to monitor and optionally control intrinsic characteristics of bio organisms via application of external magnetic fields. Due to the ME effect, when placed in the microenvironment of a biomolecular sample, MENs’ magnetic properties change to reflect the molecular nature of the sample. Such an unprecedented intrinsic connection to cells and …

Sensing Gyroscopic Properties Of Rotating Magnetic Nanoparticles In Solution, Brian Gerald Krug

Dissertations

A new sensor using magnetic nanoparticles and rotating magnetic fields has been developed. By spinning the nanoparticles in a rotating magnetic field, it is feasible to infer angular position and inertia if an external force is applied to the system. The nanoparticles are treated as a multitude of miniature gyroscopes whose overall effect can be combined as one single gyroscope. Two sensors were built to test the feasibility, both containing Fe3O4 nanoparticles.

The typical input current was 250 milliamps. When the sensor deviated from its magnetic axis by a small angle, the input current changed between 1 and 2 milliamps …

Recent Progresses In Molybdenum-Based Electrocatalysts For The Hydrogen Evolution Reaction, Ze-Xing Wu, Jie Wang, Jun-Po Guo, Jing Zhu, De-Li Wang

Journal of Electrochemistry

Electrochemical catalytic production of hydrogen has been considered as a promising and sustainable strategy for clean and renewable energy technologies. Molybdenum-based non noble metal catalysts for the hydrogen evolution reaction have attracted extensive attention due to its effective catalytic performance. In this review, the recent progresses in molybdenum-carbide, phosphide, nitride and sulfide electrocatalysts are presented. In addition, the strategies to improve the catalytic performance are analyzed and the prospects for the future development trends are expected.

Heating Element Including Carbon Nanotube (Cnt) Layer, Santhosh Kumar Loganathan, Virginie Rollin, Daewon Kim

Publications

Apparatus , materials , and techniques and techniques herein can include providing a deposited layer comprising a com posite material including carbon nanotubes ( CNTs ) . Accord ing to various examples , the composite can be applied to a substrate such as using a solution containing CNTs and other constituents such as sulfur . The solution can be spray applied to a substrate , or spin - coated upon a substrate , such as to provide a uniform , conductive , and optically - transpar ent film layer . In one application , such a film layer can be …

Mens Doped Adhesive And Influence On Fracture Toughness, Kao Z. Yang

FIU Electronic Theses and Dissertations

Composites are in high demand; however, fasteners are often required for joining process and can reduce their advantages. One solution is adhesive bonding, but uncertainty exists regarding long term durability and the ability to interrogate bonds noninvasively. One potential solution to qualify bond integrity over its service life is to dope an adhesive with magneto-electric nanoparticles (MENs). MENs can yield output magnetic signatures that are influenced by bond quality and damage state. In this study, adhesives have been doped with MENs prior to bonding at 1% volume concentration. For optimum implementation, this health monitoring system should be evaluated for effects …

Intracellular Ros Mediates Gas Plasma-Facilitated Cellular Transfection In 2d And 3d Cultures, Dehui Xu, Biqing Wang, Yujing Xu, Zeyu Chen, Qinjie Cui, Yanjie Yang, Hailan Chen, Michael G. Kong

Bioelectrics Publications

This study reports the potential of cold atmospheric plasma (CAP) as a versatile tool for delivering oligonucleotides into mammalian cells. Compared to lipofection and electroporation methods, plasma transfection showed a better uptake efficiency and less cell death in the transfection of oligonucleotides. We demonstrated that the level of extracellular aqueous reactive oxygen species (ROS) produced by gas plasma is correlated with the uptake efficiency and that this is achieved through an increase of intracellular ROS levels and the resulting increase in cell membrane permeability. This finding was supported by the use of ROS scavengers, which reduced CAP-based uptake efficiency. In …

Cobalt Ferrite Nanoparticles Fabricated Via Co-Precipitation In Air: Overview Of Size Control And Magnetic Properties, Dennis Toledo

FIU Electronic Theses and Dissertations

Cobalt Ferrite has important, size-dependent magnetic properties. Consequently, an overview of particle size is important. Co-precipitation in air was the fabrication method used because it is comparatively simple and safe. The effects of three different reaction times including 1, 2, 3 hour(s) on particle size were compared. Also, the effectiveness of three different capping agents (Oleic Acid, Polyvinylpyrollidone (PVP), and Trisodium Citrate) in reducing aggregation and correspondingly particle size were examined. Using Welch’s analysis of variance (ANOVA) and the relevant post hoc tests, there was no significant difference (p=0.05) between reaction times of 1 hour and 2 hours, but there …

Nanoparticle Plasmonics: Going Practical With Transition Metal Nitrides, U. Guler, V. M. Shalaev, A. Boltasseva

U. Guler

Promising designs and experimental realizations of devices with unusual properties in the field of plasmonics have attracted a great deal of attention over the past few decades. However, the high expectations for realized technology products have not been met so far. The main complication is the absence of robust, high performance, low cost plasmonic materials that can be easily integrated into already established technologies such as microelectronics. This review provides a brief discussion on alternative plasmonic materials for localized surface plasmon applications and focuses on transition metal nitrides, in particular, titanium nitride, which has recently been shown to be a …