Nanoscience and Nanotechnology Commons^™

Fabrication Of Forcespinning® Nanofibers Incorporating Nopal Extract, Cristobal Rodriguez, Victoria Padilla, Karen Lozano, J. Andrew Mcdonald, Luis Materon, Alejandra Chapa, Fariha Ahmad, Carlos Trevino De Leon, Robert Gilkerson

Biology Faculty Publications and Presentations

In this study, nanofibers composed of Opuntia cochenillifera nopal mucilage (N) extract combined with chitosan (CH) and pullulan (PL) (N/CH/PL) were produced via Forcespinning®. The developed nonwoven composite membranes are comprised of long, continuous, and homogenous fibers with fiber average diameter varying between 251±77 nm and 406±127 nm depending on the concentration of N. After crosslinking, the developed membranes were highly stable in water. The water absorption capacity of the N/CH/PL composite nanofiber membranes was shown to be 65% higher when compared to the CH/PL nanofiber membranes. Nopal dipcoated membranes show inhibition of gram-negative Escherichia coli, indicating antibacterial properties. These …

3-D Fabry–Pérot Cavities Sculpted On Fiber Tips Using A Multiphoton Polymerization Process, Jonathan W. Smith, Jeremiah C. Williams, Joseph S. Suelzer, Nicholas G. Usechak, Hengky Chandrahalim

Faculty Publications

This paper presents 3-D Fabry–Pérot (FP) cavities fabricated directly onto cleaved ends of low-loss optical fibers by a two-photon polymerization (2PP) process. This fabrication technique is quick, simple, and inexpensive compared to planar microfabrication processes, which enables rapid prototyping and the ability to adapt to new requirements. These devices also utilize true 3-D design freedom, facilitating the realization of microscale optical elements with challenging geometries. Three different device types were fabricated and evaluated: an unreleased single-cavity device, a released dual-cavity device, and a released hemispherical mirror dual-cavity device. Each iteration improved the quality of the FP cavity's reflection spectrum. The …

Sustainable Drug Release From Polycaprolactone Coated Chitin‑Lignin Gel Fibrous Scaffolds, Turdimuhammad Abdullah, Kalamegam Gauthaman, Azadeh Mostafavi, Ahmed Alshahrie, Numan Salah, Pierfrancesco Morganti, Angelo Chianese, Ali Tamayol, Adnan Memic

Department of Mechanical and Materials Engineering: Faculty Publications

Non-healing wounds have placed an enormous stress on both patients and healthcare systems worldwide. Severe complications induced by these wounds can lead to limb amputation or even death and urgently require more effective treatments. Electrospun scaffolds have great potential for improving wound healing treatments by providing controlled drug delivery. Previously, we developed fibrous scaffolds from complex carbohydrate polymers [i.e. chitin-lignin (CL) gels]. However, their application was limited by solubility and undesirable burst drug release. Here, a coaxial electrospinning is applied to encapsulate the CL gels with polycaprolactone (PCL). Presence of a PCL shell layer thus provides longer shelf-life for the …

Engineering Electromagnetic Systems For Next-Generation Brain-Machine Interface, Brayan Ricardo Navarrete

FIU Electronic Theses and Dissertations

MagnetoElectric Nanoparticles (MENPs) are known to be a powerful tool for a broad range of applications spanning from medicine to energy-efficient electronics. MENPs allow to couple intrinsic electric fields in the nervous system with externally controlled magnetic fields. This thesis exploited MENPs to achieve contactless brain-machine interface (BMIs). Special electromagnetic devices were engineered for controlling the MENPs’ magnetoelectric effect to enable stimulation and recording. The most important engineering breakthroughs of the study are summarized below.

(I) Metastable Physics to Localize Nanoparticles: One of the main challenges is to localize the nanoparticles at any selected site(s) in the brain. The fundamental …

Editorial: Carbon- And Inorganic-Based Nanostructures For Energy Applications, Federico Cesano, M. Jasim Uddin, Yuanbing Mao, Muhammad N. Huda

Chemistry Faculty Publications and Presentations

No abstract provided.

Surface Enhanced Raman Spectroscopy (Sers) As A Nanoscale Adsorption Phenomenon: Development Of Tailored Nanomaterials For Applications In Drug Detection, Chiara Deriu

FIU Electronic Theses and Dissertations

Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique in which nanostructured substrates amplify the inherently weak Raman signal of an adsorbed species by several orders of magnitude, enabling the detection of trace compounds, up to the single molecule level. While this may be an exceptional tool for any analytical scientist, SERS is at present relegated to the role of academic sensation, and is underutilized in everyday analytical practice. The SERS community is increasingly attributing this setback to a poor understanding of nanoscale surfaces and their chemical environment; since molecular adsorption at the nanostructured surface enables SERS detection, uncertainty about …

Anisotropic Cuinse2 Nanocrystals: Synthesis, Optical Properties And Their Effect On Photoelectric Response Of Dye-Sensitized Solar Cell, Ahmed Mysara, M Mohsen Abdelaziz, A N. Emam, A S. Mansour, A A. F. Zikry, M .B Mohamed, Y H. Elbashar

Nanotechnology Research Centre

CuInSe₂ I-III-VI₂ ternary is a semiconductor considered very good efficient solar energy conversion material. An organometallic pyrolysis method is used to prepare monodisperse CuInSe₂ nanoparticles using a mixture of oleylamine, and trioctylphosphine, as capping materials. The particle shape changes to dot, rods or flowers occur via varying the reaction temperatures (160, 200, 220±C) respectively. The obtained particles have been characterized to determine the shape and size of CuInSe₂ nanoparticles using HR-TEM and XRD. The optical and electronic properties of these particles have been investigated and discussed in detail. Then the different shapes of CuInSe …

Optimal Control Of Active Nematics, Michael M. Norton, Piyush Grover, Michael F. Hagan, Seth Fraden

Department of Mechanical and Materials Engineering: Faculty Publications

In this work we present the first systematic framework to sculpt active nematic systems, using optimal control theory and a hydrodynamic model of active nematics. We demonstrate the use of two different control fields, (i) applied vorticity and (ii) activity strength, to shape the dynamics of an extensile active nematic that is confined to a disk. In the absence of control inputs, the system exhibits two attractors, clockwise and counterclockwise circulating states characterized by two co-rotating topological þ1 2 defects. We specifically seek spatiotemporal inputs that switch the system from one attractor to the other; we also examine phase-shifting perturbations. …

Microfluidic Systems With Embedded Cell Culture Chambers For High Throughput Biological Assays, Arian Jaberi, Amir Monemian Esfahani, Fariba Aghabaglou, Jae Sung Park, Sidy Ndao, Ali Tamayol, Ruiguo Yang

Department of Mechanical and Materials Engineering: Faculty Publications

The ability to generate chemical and mechanical gradients on chips is important both for creating biomimetic designs or enabling high-throughput assays. However, there is still a significant knowledge gap in the generation of mechanical and chemical gradients in a single device. In this study, we developed gradient-generating microfluidic circuits with integrated microchambers to allow cell culture and to introduce chemical and mechanical gradients to cultured cells. A chemical gradient is generated across the microchambers, exposing cells to a uniform concentration of drugs. The embedded microchamber also produces a mechanical gradient in the form of varied shear stresses induced upon cells …

Optimization Of Nitrate Removal From Aqueous Solution By Acid-Activated Rice Straw Supported Nano Zero-Valent Iron Using Response Surface Methodology, Dalia A. Ali Eng, Nagwa Mahmoud Al-Mansi Prof, Mohamed Amin Sadek Prof., Ahmad Wafiq Abolnasr Dr.

Chemical Engineering

Rice straw is one of the most common agricultural wastes due to its large production amounts. Energy valorization of rice straw is a technology used for nitrate removal as the produced ashes used to generate the adsorbent by means of an alkali dissolution followed by acid precipitation. The novelty of the proposed process is that the production of the nano zero-valent iron supported acid-activated rice straw (AARS-nZVI) adsorbent is carried out without the energy valorization process but, through an acid activation for rice straw followed by precipitation of nZVI particles on its surface. The new adsorbent synthesis, characterization and application …

Designing A Reactor Chamber For Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn Merrill, Bingjie Zhang, Jerry Larue

SURF Posters and Papers

Catalysis provides pathways for efficient and selective chemical reactions by lowering the energy barriers for desired products. Gold nanoparticles (AuNPs) show excellent promise as plasmonic catalysts. Plasmonic materials have localized surface plasmon resonances, oscillations of the electron bath at the surface of a nanoparticle, that generate energetically intense electric fields which rapidly decay into energetically excited electrons. The excited electrons have the potential to destabilize atoms strongly bound to the catalysts through occupation of antibonding orbitals. Tuning the antibonding orbitals to make them accessible for occupancy by electrons is achieved by coating the AuNP in a thin layer of another …

Comparison Of Plantar Pressure Profile Of Young Adults During Training On Elliptical Devices And Overground Walking: A Pilot Study, Guilherme Manna Cesar, Thad W. Buster, Judith M. Burnfield

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Elliptical training may offer advantages over other cardiorespiratory exercises for those requiring podiatric care, since its constant double-limb support diminishes recurring high-impact plantar forces while allowing exercise in a functional, upright posture. Unknown is the impact of distinct elliptical models, that can alter user’s body mechanics, on potential variations in plantar pressure patterns.

Purpose: To compare plantar pressure variables while exercising on four ellipticals and walking.

Methods: For this cross-sectional pilot study, plantar pressure data were recorded from ten young adults while exercising on four ellipticals (True, Octane, Life Fitness, SportsArt) and walking overground. One-way repeated measures ANOVA identified …

Nonlinear Nanophotonic Devices In The Ultraviolet To Visible Wavelength Range, Jinghan He, Hong Chen, Jin Hu, Jingan Zhou, Yingmu Zhang, Andre Kovach, Constantine Sideris, Mark C. Harrison, Yuji Zhao, Andrea M. Armani

Engineering Faculty Articles and Research

Although the first lasers invented operated in the visible, the first on-chip devices were optimized for near-infrared (IR) performance driven by demand in telecommunications. However, as the applications of integrated photonics has broadened, the wavelength demand has as well, and we are now returning to the visible (Vis) and pushing into the ultraviolet (UV). This shift has required innovations in device design and in materials as well as leveraging nonlinear behavior to reach these wavelengths. This review discusses the key nonlinear phenomena that can be used as well as presents several emerging material systems and devices that have reached the …

Magnetically Induced Carrier Distribution In A Composite Rod Of Piezoelectric Semiconductors And Piezomagnetics, Guolin Wang, Jinxi Liu, Wenjie Feng, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In this work, we study the behavior of a composite rod consisting of a piezoelectric semiconductor layer and two piezomagnetic layers under an applied axial magnetic field. Based on the phenomenological theories of piezoelectric semiconductors and piezomagnetics, a one-dimensional model is developed from which an analytical solution is obtained. The explicit expressions of the coupled fields and the numerical results show that an axially applied magnetic field produces extensional deformation through piezomagnetic coupling, the extension then produces polarization through piezoelectric coupling, and the polarization then causes the redistribution of mobile charges. Thus, the composite rod exhibits a coupling between the …

Lstm-Based Anomaly Detection For Non-Linear Dynamical System, Yue Tan, Chungjing Hu, Kuan Zhang, Kan Zeng, Ethan A. Davis, Jae Sung Park

Department of Mechanical and Materials Engineering: Faculty Publications

Anomaly detection for non-linear dynamical system plays an important role in ensuring the system stability. However, it is usually complex and has to be solved by large-scale simulation which requires extensive computing resources. In this paper, we propose a novel anomaly detection scheme in non-linear dynamical system based on Long Short-Term Memory (LSTM) to capture complex temporal changes of the time sequence and make multi-step predictions. Specifically, we first present the framework of LSTM-based anomaly detection in non-linear dynamical system, including data preprocessing, multi-step prediction and anomaly detection. According to the prediction requirement, two types of training modes are explored …

Geometric Optimization Of Plasmonic Nanostructure Arrays On Mwir Hgcdte (Mct), Nagendrababu Vanamala, Kevin C. Santiago, Naresh C. Das, Samuel Keith Hargrove

Mechanical and Manufacturing Engineering Faculty Research

Mercury Cadmium Telluride (MCT) is a primary absorber material used in most infrared (IR) detection technologies. Our previous studies show that the optical absorbance profile of MCT in the mid-infrared region can be enhanced by 13% under ambient conditions via integrating periodic Indium Tin Oxide (ITO) nanostructures. Here, we focus on the geometrical parameterization and optimization of ITO nanostructure arrays. We simulate several types of geometries, their corresponding effective absorption profiles, E-field distribution, and optimal geometric parameters. This work may lead to improved light collection and absorption edge engineering, as MCT continues to be the material of choice in IR …

Detection Of Hydroxyl Radicals Using Cerium Oxide/Graphene Oxide Composite On Prussian Blue, Surachet Duanghathaipornsuk, Sushil R. Kanel, Emily F. Haushalter, Jessica Ruetz, Dong-Shik Kim

Faculty Publications

A composite sensor consisting of two separate inorganic layers of Prussian blue (PB) and a composite of cerium oxide nanoparticles (CeNPs) and graphene oxide (GO), is tested with •OH radicals. The signals from the interaction between the composite layers and •OH radicals are characterized using cyclic voltammetry (CV). The degradation of PB in the presence of H₂O₂ and •OH radicals is observed and its impact on the sensor efficiency is investigated. The results show that the composite sensor differentiates between the solutions with and without •OH radicals by the increase of electrochemical redox current in the presence …

Size-Dependent Inhibitory Effects Of Antibiotic Nanocarriers On Filamentation Of E. Coli, Preeyaporn Songkiatisak, Feng Ding, Pavan Kumar Cherukuri, Xiao-Hong Nancy Xu

Chemistry & Biochemistry Faculty Publications

Multidrug membrane transporters exist in both prokaryotic and eukaryotic cells and cause multidrug resistance (MDR), which results in an urgent need for new and more effective therapeutic agents. In this study, we used three different sized antibiotic nanocarriers to study their mode of action and their size-dependent inhibitory effects against Escherichia coli (E. coli). Antibiotic nanocarriers (AgMUNH–Oflx NPs) with 8.6 × 10², 9.4 × 10³ and 6.5 × 10⁵ Oflx molecules per nanoparticle (NP) were prepared by functionalizing Ag NPs (2.4 ± 0.7, 13.0 ± 3.1 and 92.6 ± 4.4 nm) with a monolayer …

Probing Nanoelectroporation And Resealing Of The Cell Membrane By The Entry Of Ca2+ And Ba2+ Ions, Wenfei Bo, Mantas Silkunas, Uma Mangalanathan, Vitalij Novickij, Maura Casciola, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Andrei G. Pakhomov

Bioelectrics Publications

The principal bioeffect of the nanosecond pulsed electric field (nsPEF) is a lasting cell membrane permeabilization, which is often attributed to the formation of nanometer-sized pores. Such pores may be too small for detection by the uptake of fluorescent dyes. We tested if Ca²⁺, Cd²⁺, Zn²⁺, and Ba²⁺ ions can be used as nanoporation markers. Time-lapse imaging was performed in CHO, BPAE, and HEK cells loaded with Fluo-4, Calbryte, or Fluo-8 dyes. Ca²⁺ and Ba²⁺ did not change fluorescence in intact cells, whereas their entry after nsPEF increased fluorescence within <1 ms. The threshold for one 300-ns pulse was at 1.5–2 kV/cm, much lower than >7 …

Quantifying Wicking In Functionlized Surfaces, Maureen Winter, Ryan Regan, Alfred Tsubaki, Craig Zuhlke, Dennis Alexander, George Gogos

UCARE Research Products

Wicking remains the enigmatic key factor in many research areas. From boiling in power plants, to anti-icing on plane wings, to medical instruments, to heat pipes, efficiency and safety depend on how quickly a surface becomes wet. Yet wicking remains difficult to quantify and define as a property of the surface. This experiment strives to measure the wicking property by examining the rate that a liquid can be pulled out of a container. A superhydrophilic surface is placed in contact with the liquid at the bottom of a tube so that the volume flow rate across the surface can be …

Enhanced Carrier Transport By Transition Metal Doping In Ws2 Field Effect Transistors, Maomao Liu, Sichen Wei, Simran Shahi, Hemendra Nath Jaiswal, Paolo Paletti, Sara Fathipour, Maja Remskar, Jun Jiao, Wansik Hwang, Fei Yao, Huamin Li

Physics Faculty Publications and Presentations

High contact resistance is one of the primary concerns for electronic device applications of two-dimensional (2D) layered semiconductors. Here, we explore the enhanced carrier transport through metal–semiconductor interfaces in WS₂ field effect transistors (FETs) by introducing a typical transition metal, Cu, with two different doping strategies: (i) a “generalized” Cu doping by using randomly distributed Cu atoms along the channel and (ii) a “localized” Cu doping by adapting an ultrathin Cu layer at the metal–semiconductor interface. Compared to the pristine WS₂ FETs, both the generalized Cu atomic dopant and localized Cu contact decoration can provide a Schottky-to-Ohmic contact …

A Wirelessly Controlled Smart Bandage With 3d-Printed Miniaturized Needle Arrays, Hossein Derakhshandeh, Fariba Aghabaglou, Alec Mccarthy, Azadeh Mostafavi, Chris Wiseman, Zack Bonick, Ian Ghanavati, Seth Harris, Craig Kreikemeier-Bower, Seyed Masoud Moosavi Basri, Jordan Rosenbohm, Ruiguo Yang, Pooria Mostafalu, Dennis Orgill, Ali Tamayol

Department of Mechanical and Materials Engineering: Faculty Publications

PUBLIC ACCESS

Cycle-To-Cycle Flow Variations In A Square Duct With A Symmetrically Oscillating Constriction, Erica Sherman, Lori M. Lambert, Bethany White, Michael H. Krane, Timothy Wei

Department of Mechanical and Materials Engineering: Faculty Publications

Spatially and temporally resolved Digital Particle Image Velocimetry (DPIV) measurements are presented of flow complexities in a nominally two-dimensional, symmetric, duct with an oscillating constriction. The motivation for this research lies in advancing the state-of-the-art in applying integral control volume analysis to modeling unsteady internal flows. The specific target is acoustic modeling of human phonation. The integral mass and momentum equations are directly coupled to the acoustic equations and provide quantitative insight into acoustic source strengths in addition to the dynamics of the fluid-structure interactions in the glottis. In this study, a square cross-section duct was constructed with symmetric, computer …

In-Situ Gold-Ceria Nanoparticles: Superior Optical Fluorescence Quenching Sensor For Dissolved Oxygen, Nader Shehata, Ishac Kandas, Effat Samir

Electrical & Computer Engineering Faculty Publications

Cerium oxide (ceria) nanoparticles (NPs) have been proved to be an efficient optical fluorescent material through generating visible emission (~530 nm) under violet excitation. This feature allowed ceria NPs to be used as an optical sensor via the fluorescence quenching Technique. In this paper, the impact of in-situ embedded gold nanoparticles (Au NPs) inside ceria nanoparticles was studied. Then, gold–ceria NPs were used for sensing dissolved oxygen (DO) in aqueous media. It was observed that both fluorescence intensity and lifetime were changed due to increased concentration of DO. Added gold was found to enhance the sensitivity of ceria to DO …

Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, Meikun Shen, Tianben Ding, Steven T. Hartman, Fudong Wang, Christina Krucylak, Zheyu Wang, Che Tan, Bo Yin, Rohan Mishra, Matthew D. Lew, Bryce Sadtler

Electrical & Systems Engineering Publications and Presentations

Defect engineering is a strategy that has been widely used to design active semiconductor photocatalysts. However, understanding the role of defects, such as oxygen vacancies, in controlling photocatalytic activity remains a challenge. Here, we report the use of chemically triggered fluorogenic probes to study the spatial distribution of active regions in individual tungsten oxide nanowires using super-resolution fluorescence microscopy. The nanowires show significant heterogeneity along their lengths for the photocatalytic generation of hydroxyl radicals. Through quantitative, coordinate-based colocalization of multiple probe molecules activated by the same nanowires, we demonstrate that the nanoscale regions most active for the photocatalytic generation of …

Buckling Of Blue Phosphorus Nanotubes Under Axial Compression: Insights From Molecular Dynamics Simulations, Shiping Jiang, Huiling Wu, Liangzhi Kou, Chun Tang, Chengyuan Wang, Changfeng Chen

Physics & Astronomy Faculty Research

We report on mechanical properties of blue phosphorus nanotubes (BluePNTs) from systematic molecular dynamics simulations, adopting a Stillinger-Weber potential with parameters determined by fitting to energetic and structural data from first-principles calculations. Our results corroborate the previously reported bending poison effect and size-dependent buckling behaviors. Under axial compression, current simulations predict a shell-to-column buckling mode transition for BluePNTs with increasing aspect ratios; further compression of BluePNTs with large aspect ratios results in a column-to-shell buckling mode transition. Associated critical buckling strains can be described by the continuum mechanics theory. We also simulated buckling behavior of black phosphorus nanotubes (BlackPNTs) and …

Nanothermomechanical And And Or Logic Gates, Ahmed Hamed, Sidy Ndao

Department of Mechanical and Materials Engineering: Faculty Publications

Today’s electronics cannot perform in harsh environments (e.g., elevated temperatures and ionizing radiation environments) found in many engineering applications. Based on the coupling between near-field thermal radiation and MEMS thermal actuation, we presented the design and modeling of NanoThermoMechanical AND, OR, and NOT logic gates as an alternative, and showed their ability to be combined into a full thermal adder to perform complex operations. in this work, we introduce the fabrication and characterization of the first ever documented Thermal AND and OR logic gates. Theresults show thermal logic operations can be achieved successfully through demonstrated and easy-to- manufacture nanothermoMechanical logic …

Variations In Plantar Pressure Variables Across Elliptical Trainers In Older Adults, Judith M. Burnfield, Guilherme Manna Cesar, Thad W. Buster

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Ellipticals are used to address walking and cardiorespiratory training goals of older adults, some of whom are at risk for foot injuries. Variations in joint kinematics and muscle demands when using different ellipticals could lead to plantar pressure differences. This study explored plantar pressure variables during gait and use of four ellipticals.

Methods: Plantar pressures were recorded while 10 adults [68.1 (4.5) years] walked and used the True, Octane, Life Fitness, and SportsArt ellipticals. Repeated-measures ANOVAs (5 × 1) identified forefoot and heel differences across conditions.

Findings: Maximum forefoot forces and peak pressures were significantly lower than walking for …

Challenges In Path Planning Of High Energy Density Beams For Additive Manufacturing, Karunakaran K. P, Seema Negi, Arun Nambolan, Yogesh Patil, Milan Pandya, Sajan Kapil, Dmitriy Trushnikov, Michael P. Sealy, Alain Bernard

Department of Mechanical and Materials Engineering: Faculty Publications

As there are no cutting forces in High Energy Density (HED) beams like lasers and Electron Beam (EB), their speeds are limited only by their positioning systems. On the other hand, as the entire matrix of the 3D printed part has to be addressed by the thin beam in multiple passes in multiple layers, they have to travel several kilometers in tiny motions. Therefore, the acceleration of the motion system becomes the limiting factor than velocity or precision. The authors have proposed an area-filling strategy for EB to fill the layer with optimal squares to exploit analog and hardware computing. …

Low- And High-Drag Intermittencies In Turbulent Channel Flows, Rishav Agrawal, Henry C.-H. Ng, Ethan A. Davis, Jae Sung Park, Michael D. Graham, David J.C. Dennis, Robert J. Poole

Department of Mechanical and Materials Engineering: Faculty Publications

Recent direct numerical simulations (DNS) and experiments in turbulent channel flow have found intermittent low- and high-drag events in Newtonian fluid flows, at Reτ = uτh/ν between 70 and 100, where uτ, h and ν are the friction velocity, channel half-height and kinematic viscosity, respectively. These intervals of low-drag and high-drag have been termed “hibernating” and “hyperactive”, respectively, and in this paper, a further investigation of these intermittent events is conducted using experimental and numerical techniques. For experiments, simultaneous measurements of wall shear stress and velocity are carried out in a channel flow facility using hot-film anemometry (HFA) and laser …