Engineering Commons^™

Design Of High Temperature Ti–Al–Cr–V Alloys For Maximum Thermodynamic Stability Using Self-Organizing Maps, Rajesh Jha, George S. Dulikravich

Department of Mechanical and Materials Engineering

Data generated for the Ti–Al–Cr–V system of metallic alloys from our previous publication, where the composition of 102 alloys were computationally Pareto optimized with the objective of simultaneously maximizing the Young’s modulus and minimizing density for a range of temperatures, was the starting point of the current research, where compositions at different temperatures of these alloys were analyzed for phase stability in order to generate new data for compositions and volume fractions of stable phases at various temperatures. This resulted in a large dataset where a lot of data were still missing as all the phases are not stable at …

Design Of High Temperature Ti–Al–Cr–V Alloys For Maximum Thermodynamic Stability Using Self-Organizing Maps, Rajesh Jha, George S. Dulikravich

Department of Mechanical and Materials Engineering

Data generated for the Ti–Al–Cr–V system of metallic alloys from our previous publication, where the composition of 102 alloys were computationally Pareto optimized with the objective of simultaneously maximizing the Young’s modulus and minimizing density for a range of temperatures, was the starting point of the current research, where compositions at different temperatures of these alloys were analyzed for phase stability in order to generate new data for compositions and volume fractions of stable phases at various temperatures. This resulted in a large dataset where a lot of data were still missing as all the phases are not stable at …

Quantification Of Thermal Oxidation In Metallic Glass Powder Using Ultra-Small Angle X-Ray Scattering, Tanaji Paul, Linqi Zhang, Sourabh Biswas, Archana Loganathan, Matthew G. Frith, Jan Ilavsky, Ivan Kuzmenko, Jim Puckette, A. Kaan Kalkan, Arvind Agarwal, Sandip P. Harimkar

Department of Mechanical and Materials Engineering

In this paper, the composition, structure, morphology and kinetics of evolution during isothermal oxidation of Fe 48Cr 15Mo 14Y 2C 15B 6 metallic glass powder in the supercooled region are investigated by an integrated ex-situ and in-situ characterization and modelling approach. Raman and X-ray diffraction spectra established that oxidation yielded a hierarchical structure across decreasing length scales. At larger scale, Fe 2O 3 grows as a uniform shell over the powder core. This shell, at smaller scale, consists of multiple grains. Ultra-small angle X-ray scattering intensity acquired during isothermal oxidation of the powder over a wide Q-range delineated direct quantification …

Atmospheric Plasma Treatment Enhances The Biosensing Properties Of Graphene Oxide-Silver Nanoparticle Composite, Apurva Sonawane, Mubarak A. Mujawar, Shekhar Bhansali

Electrical and Computer Engineering Faculty Publications

This work presents an approach to tailor the properties of the graphene oxide- silver nanoparticle (GO-AgNPs) composite using room temperature atmospheric plasma treatment. In particular, the aerosolized deposition of graphene oxide-silver nanoparticle composite (GO-AgNPs), the rapid reduction of GO at room temperature, and AgNPs surface excitation are investigated in this work. The plasma treatment of aerosolized GO leads to the reduced graphene oxide (rGO) formation which is observed from the increase in D to G band ratio from 0.65 for GO to 1.2 for rGO in the Raman spectra. Scanning Electron Microscopy, Transmission Electron Microscopy, and Selected Area Electron Diffraction …

Ultra Violet Disinfection In Waste Water Treatment Plants, Terry Reyes

Undergraduate Research at FIU (URFIU) Conference

Disinfection is one of the last processes in waste water treatment plants before the effluent is discarded. Its goal is to rid of any potential pathogens, suspended solids, organics or any contaminants. The current, most widely used disinfection method in waste water treatment plants nationally is chlorine disinfection. It is a well-established and cheap technology. Even though it is an effective method for pathogenic microorganism disinfection, it does have certain health and safety limitations, along with environmental concerns. In this study we observe an alternative technology, Ultra Violet (UV) disinfection. We explore the type of microorganisms and pathogens that are …

Time-Dependent Mechanical Properties Of Pdms For Micro Tissue Gauges, Nicole Bacca

Undergraduate Research at FIU (URFIU) Conference

PDMS (Polydimethylsiloxane) is commonly used for biological experiments due to its biocompatibility, and elasticity. However, the use of PDMS materials as platforms in tissue engineering, specifically as the pillars for micro tissue gauges (?TUGs), means a continuous contraction of the cells (cardiomyocytes) against the PDMS posts. This behavior created the need to know the mechanical properties of the PDMS that will receive this continuous dynamic loading. Initial in-situ microscale deflection tests revealed a time-dependent mechanical response from the material. Inducing cyclic deflections on the posts similar to those experienced by cardiac tissue during beating (~10 ?m) resulted in the displacements …

Spark Plasma Sintered Aluminum Oxide Filter For Hot Gas Applications, Catalina M. Young

Undergraduate Research at FIU (URFIU) Conference

In this study, we report the fabrication of aluminum oxide filter via spark plasma sintering for application as a hot gas filter. Spherical alpha alumina particles were sieved to achieve uniform size distribution. A bimodal size distribution was observed, after sieving, of 180±40 μm and 109±16 μm, for the large and small particle respectively. Powder was then sintered via spark plasma sintering at varying dwell temperatures, pressures, and dwell periods to find optimal parameters to produce sufficient surface diffusion at necks between particles. A temperature of 1500C, 30 minutes dwell period, and 10-20MPa applied pressure produced filters with optimal range …

Validation Of Near Infrared Optical Scanner To Assess Saturated Oxygen Changes In Response To Breath Hold, Priscilla Lozano

Undergraduate Research at FIU (URFIU) Conference

A near-infrared optical scanner (NIROS) was developed in-house, to determine relative oxygenated (DHbO) and deoxygenated (DHbR) hemoglobin levels in the wound and the surrounding tissue. The goal of this study is to measure perfusion changes in terms of saturated oxygen in subsurface tissues as a response to a breath-holding paradigm using NIROS, and validated against a hospital grade pulse oximeter and photo-spectrometer. Comparison of perfusion changes between the devices can assist in correlating these measurements and thus calibrate and validate our recently developed NIROS device. Furthermore, assessing oxygenated perfusion change can potentially help demarcate regions of poor oxygen flow, thus …

Exploring Drivers’ Behavior And Cognition In A Driving Simulator With Eye-Tracking, Hillary Lopez

Undergraduate Research at FIU (URFIU) Conference

Intersection collision warning systems (ICWSs) have the potential to significantly improve driving and pedestrian safety. When drivers receive a warning of an upcoming pedestrian or vehicle, they are more likely to stop and thus prevent collision. Recent research shows that auditory stimuli are more effective than visual stimuli when it comes to warning modality (Bella & Silvestri, 2017). Thanks to driving simulators, driver behavior metrics-- and more recently-- driver attention and cognition captured via eye-tracking (e.g. Herwitz & Monsere, 2013)-- can be measured. To date, however, no study has examined driver cognition simultaneously while receiving an ICWS warning. The purpose …

Ultra-Wideband Interference Resistant System For Multi-User Communication, Alfredo Gonzalez

Undergraduate Research at FIU (URFIU) Conference

In the emergence of high frequency systems comes the opportunity to investigate the possibilities of ultra-wideband (UWB) techniques. These UWB capabilities give presence to higher data rates and opens a door for techniques to ensure commination security. Secure communication is vital for mission critical scenarios, environments abundant with malicious interference, and areas with congesting transmissions. Being able to have a variety of techniques available to counteract these unfavorable scenes and as well satisfy high data rates of current technology is a goal that this paper aims to contribute in. We present here an investigation into an ultra-wideband system that is …

Boron Nitride Nanotube Reinforced Magnesium Composite By Spark Plasma Sintering, Noemie Denis

Undergraduate Research at FIU (URFIU) Conference

Boron Nitride Nanotube (BNNT) is a high strength, high stiffness and highly thermally stable lightweight nanomaterial. BNNTs are appealing for mechanical reinforcement applications, and can be added to the lightweight metals, such as Aluminum and Magnesium to improve their mechanical properties. Mechanical properties of reinforced metals are heavily influenced by interfacial reactions between the metal and the nanotubes. In this study, Magnesium alloy (AZ31) is reinforced with BNNT through spark plasma sintering (SPS). The composite is processed at 400 ºC, which can induce chemical reactions between the alloy and the nanotubes. The focus is to understand the reactivity at interface …

Doctor’S Cyclo-Massage – Cycloidal Vibration Therapy, Monserrat G. Otarola

Undergraduate Research at FIU (URFIU) Conference

Body pain can be one of the most common reasons for visits to the doctor. It can be present in many body locations and be caused by different reasons, such as tension, stress, fatigue or other medical conditions. In many cases, users suffering from body pain, muscle stiffness and neuropathies have no reliable solution in their everyday lives to alleviate their symptoms. The project will investigate Doctor’s Cyclo-Massage in order to detect and analyze the current failures in the field that are compromising reliability and functionality of the device, to perform a redesign that will mitigate the mechanical and electrical …

Detection Of Circulating Tumor Cells For Early Diagnosis Of Cancer On A Microfluidic Platform, Kristopher Odiete

Undergraduate Research at FIU (URFIU) Conference

Circulating tumor cells (CTCs) act as an early biomarker representing metastatic cancer, in which cells from a benign tumor release out into the bloodstream. These cells anchor to other organs of the body and begin to use the tissue as a scaffold for growth, leading to rapid progression of cancer. Metastatic cancer is at fault for the rise of breast, prostate, and brain cancer, which have high mortality rates (606, 880 cancer deaths in the U.S). Current techniques such as surgical and liquid biopsies are invasive and inefficient for early detection of cancer. In this work, we propose the capture …

Identifying Key Components Of Extracellular Matrix In Vascularized Skeletal Muscle Tissues, Patricia Garcia

Undergraduate Research at FIU (URFIU) Conference

Engineered skeletal muscle tissues have recently been used for a variety of applications in the development of actuators for bio-robots, pre-clinical drug advances, and transplantation. In native muscle tissues, fibroblasts contribute to the formation of the extracellular matrix (ECM) layer, called endomysium, which is located between myofibers and capillaries. Because the ECM layer is known to have significant mechanical and biological roles, it can protect myofibers during contraction, control muscle development, and mediate cell to cell interactions. However, there is a lack of knowledge in establishing key components of the ECM, especially in engineered skeletal muscles, which affect differentiation of …

Techniques In Theranostic Ormosil Nanoparticle Fabrication For Cancer Therapy, Romina Doubnia

Undergraduate Research at FIU (URFIU) Conference

Organically Modified Silica (ORMOSIL) nanoparticles have been studied for chemotherapeutic, photodynamic, gene delivery and bioimaging applications, and have improved pharmacokinetic properties, controlled release of the drug and lowered toxicity. This project emphasizes on making ORMOSIL through two different approaches to generate drug encapsulating medium for theranostics.The quality of these nanoparticles is determined by measuring the size, polydispersity index (PDI), and the quantity of functional groups on the surface. The size of nanoparticles is critical to take advantage of the Enhanced Permeability and Retention Effect (EPR) of most tumors, which makes size optimization an integral aim for this project. These nanoparticles …

Assessing Biocompatibility Of Polymeric Materials As Scaffolds To Establish 3d Cell Culture In A Microfluidic Platform, Dennis Ramos Trinindad

Undergraduate Research at FIU (URFIU) Conference

morphology, cellular environment and understanding their behavioral changes. The implementation of 3D cell culture systems into diagnostics, drug discovery and fundamental research in the field of life sciences for both academic and industrial applications has generated deeper insights leading towards early identification of various disease, assessing new drugs and treatment, and even genome sequencing. The current techniques for establishing a 3D cell culture requires a scaffold material which acts as an anchorage for cells to grow. The materials available have a certain limitation in term of biocompatibility and biodegradability. In this work, we intend to explore different polymeric materials which …

Using Tunable Resistive Pulse Sensing To Identify And Quantify Extracellular Vesicles, Jessica E. Molina

Undergraduate Research at FIU (URFIU) Conference

Calcification, the leading predictor of and direct contributor to cardiovascular disease, begins with the release of small, ~100 nm sized extracellular vesicles (EVs) by cells in response to pathological conditions such as plaque formation in arteries. Studies have shown that calcifying EVs released in bone possess a negative charge, which plays a vital role in the calcification process. These calcifying EVs exist within larger populations of vesicles released during normal cellular processes. One of the biggest challenges in studying EVs comes from their heterogeneity and small size. There are no methods that currently exist to separately assess and quantify calcifying …

Pcr Machine, Alain A. Perez

Undergraduate Research at FIU (URFIU) Conference

This research aims to create and manufacture a smaller, economical Handheld PCR (Polymerase chain reaction) machine which is also known as a thermal cycler. The PCR machine is widely used in the area of molecular diagnostics, forensics, genetics as well as early detection of diseases. The function of a typical PCR machine is to amplify DNA using a polymerase enzyme which works by amplifying the DNA to several number of copies by cycling the temperature of the mixture. The conventional PCR machine involves heating block or plates as a heater which is connected to a PID controller due to which …

Experimental Comparison Of Active And Passive Battery Management Systems For E-Bike Battery Application, Reynier Serpa

Undergraduate Research at FIU (URFIU) Conference

Studies have shown that without a proper battery management system (BMS), batteries in a battery pack degrade much faster and this in turn affects the lifespan of the entire battery pack. These battery management systems monitor the voltage levels of each battery cell in order to ensure that all cells are at the same charge level as well as prevent any battery cell from being charged above (or discharged below) its safe voltage limit. The DC2064A BMS with active flyback multi-core multiwinding topology and the BQ77PL900EVM BMS with passive charge shunt topology were examined in order to compare the differences …

Tissue Oxygenation Changes In A Large Diabetic Foot Ulcer: Longitudinal Case Study, Maria Saavedra

Undergraduate Research at FIU (URFIU) Conference

Diabetic Foot Ulcers (DFUs) are responsible for 20% of diabetic-related hospitalization and for 85% of diabetes related amputations. A near-infrared optical scanner (NIROS) was developed to image for tissue oxygenation of DFUs and assessing the healing status of the wounds. The device was capable to imaging smaller DFUs but was limited to image large wounds. A non-contact hand-held NIROS was developed to image large tissue surfaces. NIROS was used to collect diffused reflected images at 10Hz frequency and the light source is composed of several multi-wavelengths LEDs covering a range of 600-900nm and with a 10Hz frequency. This allowed collection …

Computational Analysis Of Spark Plasma Sintering: Heat Transfer And Temperature Distribution, Rodolfo Fernandez

Undergraduate Research at FIU (URFIU) Conference

Spark Plasma Sintering is a tool that offers a very effective and fast sintering process, however there are many unknowns on how this technology is so effective at sintering powders. Computational analysis of SPS shows promise to explain the different sintering processes that occur during SPS and will be able to serve as a functional tool to optimize and predict future SPS runs. In this study, the computational analysis of an SPS experiment is conducted utilizing the finite element analysis package COMSOL®. Meaningful data, such as relative density prediction, can be potentially obtained throughout the use of this technique. However …

Ion Channel Expression Regulation By Sodium And Potassium In Vascular Endothelial Cells, Monica Karas

Undergraduate Research at FIU (URFIU) Conference

Introduction: Changes in the expression of ion channels, and of genes involved in membrane potential (Vm) homeostasis and Ca2 +s ignaling have been associated with pathological conditions such as hypertension (1,2,3,4). Little is known, however, for the mechanisms that regulate the expression of the approximately 400 genes encoding for subunits of the 200-250 ion channels. There is evidence that a feedback system exists, capable of sensing changes in cell electrophysiology (5 ) that leads to altering ion channel transcription levels. The variable(s) that are sensed and controlled have not been established although Na+ / K+ sensitive transcriptome has been reported …

Retrofitting Of Bridge Elements Subjected To Predominantly Axial Load Using Uhpc Shell, Mahsa Farzad

FIU Electronic Theses and Dissertations

In the United States, ~30% of the ~600,000 highway bridges are categorized as structurally deficient or functionally obsolete. These bridges should be replaced or upgraded to sustain the transportation needs of the growing public and private sectors of the U.S. economy. It is not uncommon for structures to have advanced levels of corrosion-induced damage where major repair and maintenance works are required. However, the transportation infrastructure may undergo disruption during rehabilitation causing interruption to critical economic public, civil and commercial activities. This mandates the development of new techniques and materials for accelerated rehabilitation and resilience. To address this issue, a …

Construction Workers' Health And Safety During Post Disaster Reconstruction Phase: A Case Study In Nepal, S M Jamil Uddin

FIU Electronic Theses and Dissertations

The understanding of the concept of construction workers’ health and safety during the post-disaster reconstruction (PDR) phase is still unexplored. The objective of this study is to identify a knowledge gap in the literature through systematic literature review and to find out factors that affect the health and safety of the workers during PDR. To achieve the objectives, in-depth semi-structured interviews are conducted with different stakeholders such as Owners, General Contractors, Government Officials, Safety Supervisors, Engineers and Construction Workers in the context of Nepal Earthquake 2015. Interviews are conducted in a way that the respondents represent a wide range of …

Control And Optimization Of Energy Storage In Ac And Dc Power Grids, Samy Mohamed

FIU Electronic Theses and Dissertations

Energy storage attracts attention nowadays due to the critical role it will play in the power generation and transportation sectors. Electric vehicles, as moving energy storage, are going to play a key role in the terrestrial transportation sector and help reduce greenhouse emissions. Bulk hybrid energy storage will play another critical role for feeding the new types of pulsed loads on ship power systems. However, to ensure the successful adoption of energy storage, there is a need to control and optimize the charging/discharging process, taking into consideration the customer preferences and the technical aspects. In this dissertation, novel control and …

A Constructal Approach To The Design Of Inflected Airplane Wings, Shanae Powell

FIU Electronic Theses and Dissertations

Aeroelastic instabilities such as flutter can be accurately captured by state-of-the-art aeroelastic analysis methods and tools. However, these tools and methods fall short in exposing the reasons behind the occurrence of such instabilities. In this research, the constructal law is used to discover the main cause of the variation in the flutter speed and stress distribution for inflected aircraft wings when compared to its uninflected counterpart. This law considers the design as a physics phenomenon and uses an evolutionary flow principle to explain and predict the occurrence of energy flow configurations (i.e. the flow of stresses throughout the structure).

For …

Nanoparticle-Based Spintronic Computer Logic Switch, Kevin Luongo

FIU Electronic Theses and Dissertations

Spintronics is a rapidly growing research field due to scalability, integrablility within existing VLSI architecture, significantly reduced switching energy and latency while maintaining stable bit orientation (Spin-up, Spin-down). For the first time sub-5nm Spin Transfer Torque –Magnetic Tunneling Junctions (STT-MTJ) were investigated utilizing various Integrated Circuit (IC) fabrication techniques to evaluate novel concepts in logic switches.

Tunneling Magnetoresistance (TMR) was measured in STT-MTJ stacks of Ta/CoFeB/MgO/CoFeB/Ta with differing diameter ferrimagnetic CoFe2O4 nanoparticles (10nm, 4nm and 2nm) embedded in the MgO layer. MR was detected in the 2nm and 4nm particle devices and demonstrated evidence of single electron transport.

Tri-layer STT-MTJ …

Cloud Workload Allocation Approaches For Quality Of Service Guarantee And Cybersecurity Risk Management, Soamar Homsi

FIU Electronic Theses and Dissertations

It has become a dominant trend in industry to adopt cloud computing --thanks to its unique advantages in flexibility, scalability, elasticity and cost efficiency -- for providing online cloud services over the Internet using large-scale data centers. In the meantime, the relentless increase in demand for affordable and high-quality cloud-based services, for individuals and businesses, has led to tremendously high power consumption and operating expense and thus has posed pressing challenges on cloud service providers in finding efficient resource allocation policies.

Allowing several services or Virtual Machines (VMs) to commonly share the cloud's infrastructure enables cloud providers to optimize resource …

Study Of Charge Carrier Transport In Graphene And Graphite As Two Dimensional And Quasi-Two Dimensional Materials And Their Interfaces, Nalat Sornkhampan

FIU Electronic Theses and Dissertations

Evidence of superconductivity in phosphorous-doped graphite and graphene has been observed at temperatures in the vicinity of 260 K. This evidence includes transport current, magnetic susceptibility, Hall and Nernst measurements. All of these measurements indicate a transition of a type II superconductor without a phase of type I until below the limits of the measurement capabilities.

Vortex states are inferred from periodically repeated steps in the R vs. T characteristics of Highly Oriented Pyrolytic Graphite and exfoliated doped multilayer graphene. The presence of vortices has been confirmed with thermal gradient driven Nernst measurements. Magnetic susceptibility measurements have shown results qualitatively …

Project Performance Rating Model And Ipd Implementation Guideline Metric For Water And Wastewater Treatment Plant Projects, Elie G. Andary

FIU Electronic Theses and Dissertations

The public nature of water and wastewater construction capital projects has rendered Design-Bid-Build (DBB) as the delivery method of choice for such projects over the past years. Shortcomings inherent to DBB have had a negative effect on the Key Performance Indicators (KPIs) of these projects. Numerous studies have argued that Integrated Project Delivery (IPD) improves the delivery performance of DBB projects. Project delivery performance is, however, a complex concept that is not easily measured. It involves several criteria with many factors that need to be accounted for. Water and wastewater construction projects do not have well-established overall performance rating models, …