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 …

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 …

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 …

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 …

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, …

Mesoscale Ceramic Cylindrical Ion Trap Mass Analyzers For In Situ Sample Analysis, Patrick Roman

FIU Electronic Theses and Dissertations

As wireless network devices and IOT connectivity develop, the application and demand for small, low power, in situ sensors and instruments will expand. There are continuous efforts in the miniaturization of sensors and scientific instrument systems for conventional to field deployable and rugged hand held units for personal use to extreme harsh environment applications. This work investigates mesoscale cylindrical ion trap (CIT) mass analyzer design and the benefits of CITs realized via additive manufactured metalized ceramic material systems for improved ion signal, low power performance, and extended dynamic range. Rugged monolithic miniature mass spectrometer ceramic CIT chips have been produced …

A Spectrum Sharing Based Metering Infrastructure For Smart Grid Utilizing Lte And Wifi, Imtiaz Parvez, Arif I. Sarwat

Electrical and Computer Engineering Faculty Publications

In advanced metering infrastructure (AMI) of smart grid, WiFi is an appropriate choice for its bidirectional communication requirement to transmit data to the billing center. But, WiFi functions in the free spectrum bands and LTE also requires to use the same free bands for its network expansion being licensed spectrum is limited and expansive. LTE and WiFi can operate simultaneously in the 3.5 GHz band (also known as citizen broadband radio service (CBRS)), which has large amount of free and clean spectrum. In this paper, we propose a smart grid metering infrastructure based on fixed duty cycled LTE and WiFi, …

Development And Validation Of A Smartphone-Based Near-Infrared Optical Imaging Device To Measure Physiological Changes In-Vivo, Kacie Kaile, Anuradha Godavarty

Department of Biomedical Engineering Faculty Publications

Smartphone-based technologies for medical imaging purposes are limited, especially when it involves the measurement of physiological information of the tissues. Herein, a smartphone-based near-infrared (NIR) imaging device was developed to measure physiological changes in tissues across a wide area and without contact. A custom attachment containing multiple multi-wavelength LED light sources (690, 800, and 840 nm; and <4 mW of optical power per LED), source driver, and optical filters and lenses was clipped onto a smartphone that served as the detector during data acquisition. The ability of the device to measure physiological changes was validated via occlusion studies on control subjects. Noise removal techniques using singular value decomposition algorithms effectively removed surface noise and distinctly differentiated the physiological changes in response to occlusion. In the long term, the developed smartphone-based NIR imaging device with capabilities to capture physiological changes will be a great low-cost alternative for clinicians and eventually for patients with chronic ulcers and bed sores, and/or in pre-screening for potential ulcers in diabetic subjects.

Optical Phantoms For Biomedical Polarimetry: A Review, Joseph Chue-Sang, Mariacarla Gonzalez, Angie Pierre, Megan Laughrey, Ilyas Saytashev, Tatiana Novikova, Jessica C. Ramella-Roman

Department of Biomedical Engineering Faculty Publications

Calibration, quantification, and standardization of the polarimetric instrumentation, as well as interpretation and understanding of the obtained data, require the development and use of well-calibrated phantoms and standards. We reviewed the status of tissue phantoms for a variety of applications in polarimetry; more than 500 papers are considered. We divided the phantoms into five groups according to their origin (biological/nonbiological) and fundamental polarimetric properties of retardation, depolarization, and diattenuation. We found that, while biological media are generally depolarizing, retarding, and diattenuating, only one of all the phantoms reviewed incorporated all these properties, and few considered at least combined retardation and …

The Effect Of Proteome And Lipidome On The Behavior Of Membrane Bound Systems In Thermally-Assisted Acoustophoresis, Elnaz Mirtaheri

FIU Electronic Theses and Dissertations

Changes in the biomechanical properties of cells accompanying the development of various pathological conditions have been increasingly reported as biomarkers for various diseases, including cancers. In cancer cells, the membrane properties have been altered compared to their healthy counterparts primarily due to proteomic and lipidomic dysregulations conferred by the underlying pathology. The separation and selective recovery of these cells or extracellular vesicles secreted from such cells is of high diagnostic and prognostic value.

In this dissertation, the research builds on thermally-assisted acoustophoresis technique which was developed in our laboratory for the separation of vesicles of the same size, charge and …

Context-Aware Personalized Point-Of-Interest Recommendation System, Ramesh Raj Baral

FIU Electronic Theses and Dissertations

The increasing volume of information has created overwhelming challenges to extract the relevant items manually. Fortunately, the online systems, such as e-commerce (e.g., Amazon), location-based social networks (LBSNs) (e.g., Facebook) among many others have the ability to track end users' browsing and consumption experiences. Such explicit experiences (e.g., ratings) and many implicit contexts (e.g., social, spatial, temporal, and categorical) are useful in preference elicitation and recommendation. As an emerging branch of information filtering, the recommendation systems are already popular in many domains, such as movies (e.g., YouTube), music (e.g., Pandora), and Point-of-Interest (POI) (e.g., Yelp).

The POI domain has many …

Numerical Simulation Of Flushing Deposits In Pipelines, Joseph S. Coverston

FIU Electronic Theses and Dissertations

The purpose of this research is to reduce the amount of waste generated in Department of Energy nuclear cleanup efforts currently underway. Due to the highly radioactive nature of the waste, any fluid that contacts the waste must then be treated and processed as waste. To minimize the fluids contaminated during flushing, this research aims to provide a basis for the flushing of High Level Waste (HLW) pipelines. Edgar Plastic Kaolin (EPK) with solid particles of a nominal diameter of 1 micron was used as a simulacrum for HLW. An Eulerian-Eulerian simulation built in StarCCM+ software, with a k-ω turbulence …

Physiological Interference Reduction For Near Infrared Spectroscopy Brain Activity Measurement Based On Recursive Least Squares Adaptive Filtering And Least Squares Support Vector Machines, Xin Liu, Yan Zhang, Dan Liu, Qisong Wang, Ou Bai, Jinwei Sun, Peter Rolfe

Electrical and Computer Engineering Faculty Publications

Near infrared spectroscopy is the promising and noninvasive technique that can be used to detect the brain functional activation by monitoring the concentration alternations in the haemodynamic concentration. The acquired NIRS signals are commonly contaminated by physiological interference caused by breathing and cardiac contraction. Though the adaptive filtering method with least mean squares algorithm or recursive least squares algorithm based on multidistance probe configuration could improve the quality of evoked brain activity response, both methods can only remove the physiological interference occurred in superficial layers of the head tissue. To overcome the shortcoming, we combined the recursive least squares adaptive …