Engineering Commons^™

Synthesis Of Multiwall Α-Fe2o3 Hollow Fibers Via A Centrifugal Spinning Technique, Mandana Akia, K. A. Mkhoyan, Karen Lozano

Mechanical Engineering Faculty Publications

Highlights

• Hollow hematite (α-Fe2O3) fine fibers were fabricated via a simple, flexible, and scalable technique.

• An aqueous solution with iron precursor/polymer was used in the centrifugal spinning process

• Developed fibers show average wall thickness of 55 ± 15 nm and outer fiber diameter of 852 ± 86 nm

Abstract

Hollow hematite (α-Fe2O3) fine fibers with multiwall structure were synthesized by utilizing a centrifugal spinning technique. Aqueous solutions of polyvinyl pyrrolidone and iron (III) nitrate nonahydrate were prepared and spun into fibers. The precursor fibers were heat treated at 650 °C to form iron oxide fibers. Scanning electron micrographs revealed the …

A Techno-Economic Analysis Of Current Cooling Techniques In Irish Data Centres, Lee Gibbons, Bryan Coyne, David Kennedy, Sajad Alimohammadi

Articles

This research is part of a comprehensive study to determine reformative actions for cooling regimes within the Irish data centre market. To achieve this goal, preliminary Exergy, Entropy change and operational cost analyses are used. It is determined that there is no clear advantage for using one cooling method over another without knowing the data centres secondary function (e.g. district heating, energy generation). Air cooling technology is a good candidate for a highly reliable system due to the low exhaust temperatures of 30°C. Two-phase immersion is a possibility for economically viable data centres where operational costs are to be minimised, …

Bs News September/October

Building Services Engineering

No abstract provided.

Predicting The Hardness Of Turf Surfaces From A Soil Moisture Sensor Using Iot Technologies, Ann Marie Mckeon

Other

In horseracing, “the going” is a term to describe the racetrack ground conditions. In Ireland presently, a groundskeeper or course clerk walks the racecourse poking it with a blackthorn stick, assesses conditions, and declares the going – it is a subjective measurement.

This thesis will propose using remote low-cost soil moisture sensors to gather high frequency data about the soil water content in the ground and to enable informed decisions to be made. This will remove the subjective element from the ground hardness, and look at the data in an objective way.

The soil moisture sensor will systematically collect high …

Discontinuous Galerkin Vs. Ie Method For Electromagnetic Scattering From Composite Metallic And Dielectric Structures, Y.-Y. Zhu, Q.-M. Cai, R. Zhang, X. Cao, Y.-W. Zhao, B. Gao, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an efficient volume surface integral equation (VSIE) method with nonconformal discretization is developed for the analysis of electromagnetic scattering from composite metallic and dielectric (CMD) structures. This VSIE scheme utilizes curved tetrahedral (triangular) elements for volume (surface) modeling and the associated CRWG (CSWG) basis functions for volume current (surface) current modeling. Further, a discontinuous Galerkin (DG) volume integral equation (VIE) method and a DG surface integral equation (SIE) approach are adopted for dielectric and metallic parts, respectively, which allow both conformal and nonconformal volume/surface discretization improving meshing flexibility considerably. Numerical results are provided to demonstrate the accuracy, …

Compact Endfire Coupled-Mode Patch Antenna With Vertical Polarization, Haozhan Tian, Lijun Jiang, Tatsuo Itoh

Electrical and Computer Engineering Faculty Research & Creative Works

Coupled-mode patch antenna (CMPA) is able to reform the beam by manipulating the phase of the fringing fields at the edges. In this paper, a method is proposed to realize endfire radiation with vertical polarization based on the concept of CMPA. Besides the phase controlled by the coupling, the asymmetric feeding introduces additional phase shift to one of the radiation slots, which makes the beam pointing to the forward endfire direction within the whole band. The ground of the antenna is truncated to be the same size of the top patch, which eliminates the undesired effect of the ground edge …

Reliability-Based Design Optimization Of Load Sharing Systems Using Ssi-Markov Models, Arun Bala Subramaniyan, Rong Pan, Xiaoping Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a novel single loop approach to design the components of the load sharing systems by optimally allocating the failure probabilities to each component, thereby satisfying the overall system reliability requirement. The Reliability–Based Design Optimization (RBDO) of load sharing systems is computationally intensive due to the dynamic nature of component failure probabilities, since the failure of one component will vary the failure probabilities of other working components. Many RBDO methods have been successfully utilized to design individual components, however using these methods for handling system level reliability constraints is still a challenging task. This is because of a …

Control Of A Three-Phase Grid-Connected Inverter Under Non-Ideal Grid Conditions With Online Parameter Update, Vikram Roy Chowdhury, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

Three-phase grid-connected inverter modeling depends on the equivalent resistance and inductance between the inverter and the grid. However, these parameters are not fixed during the operation of the inverter and vary with the operating conditions. In this paper, a new globally stable adaptive controller is proposed to estimate these values online and update the controller during its operation. A model reference adaptive system (MRAS) based on two fictitious quantities with no physical significance is utilized, namely M = v · i∗ and N = v∗ x i, where v and i are the steady-state values of voltage and current in …

Output-Constrained Control Of Nonaffine Multiagent Systems With Partially Unknown Control Directions, Bo Fan, Qinmin Yang, Sarangapani Jagannathan, Youxian Sun

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an output-constrained control algorithm is presented for the consensus control of a class of unknown nonaffine multiagent systems (MASs) with partially unknown control directions. Our contribution includes a step forward beyond the usual consensus stabilization result to show that the outputs of agents remain within user-defined time-varying constraints. To achieve the new results, an error transformation technique is established to generate an equivalent MAS from the original one. Stabilization and consensus of the transformed agent states ensure both the satisfaction of the time-varying constraints and the consensus of the original agent states. Based on the Nussbaum gain …

Grain Size Effects In Selective Laser Melted Fe-Co-2v, Wesley Everhart, Joseph William Newkirk

Materials Science and Engineering Faculty Research & Creative Works

The material science of additive manufacturing (AM) has become a significant topic due to the unique way in which the material and geometry are created simultaneously. Major areas of research within inorganic materials include traditional structural materials, shape memory alloys, amorphous materials, and some new work in intermetallics. The unique thermal profiles created during selective laser melting (SLM) may provide new opportunities for processing intermetallics to improve mechanical and magnetic performance. A parameter set for the production of Fe-Co-2V material with additive manufacturing is developed and efforts are made to compare the traditional wrought alloy to the AM version of …

Rare But Conceivable: Determining The Likelihood Of Meteors And Other Infrequent Events, Michael S. Schmidt, Maria Vega-Westhoff

Engineering Management and Systems Engineering Faculty Research & Creative Works

In the aftermath of a rare but devastating disaster, there is a tendency to overestimate how frequent such an event may be, hence a tendency to overestimate the risk associated with such an event. Those concerned with process safety will acknowledge that though rare, events like meteors, hurricanes, and airplane crashes that can impact chemical plants are conceivable. Typically, though, they have nothing more than feelings to decide whether these events are likely enough to be considered "credible." This compiles data from the literature for several "meteors," both natural and man-made, that often become a cause of general concern after …

The Potential Of Using Micro-Sized Crosslinked Polymer Gel To Remediate Water Leakage In Cement Sheaths, Murad Abdulfarraj, Abdulmohsin Imqam

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Cementing is a major step in the construction and sealing of hydrocarbon wells. During the life cycle of the well, cement is prone to cracking due to a change in downhole conditions. This research investigates the use of micro-sized crosslinked polymer gel as a sealant material to mitigate cracked cement sheaths. Two experimental setups were designed to investigate water leakage through cement. The impact of polymer gel strength on the gel's ability to seal cement cracks was investigated using four gel strengths, including 500 pa, 1200 pa, 1450 pa, and 2440 pa. The impact of the width of the cement …

Influence Of Guayule Resin As A Bio-Based Additive On Asphalt-Rubber Binder At Elevated Temperatures, Ahmed Hemida, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study seeks to find the influence of replacing a portion of the asphalt–rubber binder with the bio-based material “guayule resin.” This replacement could be beneficial in terms of sustainability, economics, and environmental concerns related to the asphalt industry. Nine asphalt-rubber-guayule binders were investigated to find their rheological properties. Consecutively, the study proceeded with five selected binders being compared to the original asphalt (PG64-22). Investigations underwent whole matrices (crumb rubber modifier (CRM) residue included) and liquid phases (CRM residue extracted). Additionally, these properties were partially sought for their corresponding asphalt–rubber binders to compare and judge the contribution of the guayule …

Historical Changes In Lower Columbia River And Estuary Floods: A Numerical Study, Lumas Helaire, Stefan Talke, David A. Jay, Andrew Mahedy

Civil and Environmental Engineering Faculty Publications and Presentations

Over the past 150 years, the Lower Columbia River Estuary controlling depth has approximately doubled, the majority of historical wetlands and floodplain have been reclaimed, numerous infrastructure projects have altered and confined flow pathways, and significant natural and anthropogenic changes to the discharge hydrograph have occurred. To investigate the effect of these changes on tides, river slope, and flood water levels, we construct and validate numerical models that simulate flow over late nineteenth‐century and present‐day bathymetry. The models are validated using archival (1853–1877) and modern tide measurements throughout the Lower Columbia River Estuary and river stage measurements from the tidal …

Investigations Of Point Defects In Kh2Po4 Crystals Using Ab Initio Quantum Methods, Tabitha E. R. Dodson

Theses and Dissertations

Potassium dihydrogen phosphate (KH₂PO₄, or commonly called KDP) crystals can be grown to large sizes and are used for many important devices (fast optical switches, frequency conversion, polarization rotation) for high powered lasers. The nonlinear optical material has a wide intrinsic transparency range. Intrinsic point defects are responsible for several short-lived absorption bands in the visible and ultraviolet regions that affect high-power pulsed laser propagation. The primary intrinsic defects have been experimentally detected in KDP using electron paramagnetic resonance (EPR) experiments. The defect models established thus far include (i) self-trapped holes, (ii) oxygen vacancies, and (iii) …

Effects Of Carbon-Based Ablation Products On Hypersonic Boundary Layer Stability, Olivia S. Elliott

Theses and Dissertations

Hypersonic vehicles require an accurate prediction of the transition of the boundary layer for the design of the thermal protection system due to the high heating rates under turbulent flow. Many thermal protection systems are carbon-based and introduce new species, specifically CO₂, into the boundary layer flow which are known to dampen the instabilities that lead to transition for hypersonic vehicles. A Computation Fluid Dynamics study was accomplished examining the concentration of CO₂ required to impact boundary layer transition over both sharp and blunt cones. These results were used in conjunction with air-carbon ablation models models to …

Digital Holography Efficiency Experiments For Tactical Applications, Douglas E. Thornton

Theses and Dissertations

Digital holography (DH) uses coherent detection and offers direct access to the complex-optical field to sense and correct image aberrations in low signal-to-noise environments, which is critical for tactical applications. The performance of DH is compared to a similar, well studied deep-turbulence wavefront sensor, the self-referencing interferometer (SRI), with known efficiency losses. Wave optics simulations with deep-turbulence conditions and noise were conducted and the results show that DH outperforms the SRI by 10's of dB due to DH's strong reference. Additionally, efficiency experiments were conducted to investigate DH system losses. The experimental results show that the mixing efficiency (37%) is …

Hydrodynamic And Total Dissolved Solids Model Of The Tigris River Using Ce-Qual-W2, Muhanned D. Al-Murib, Scott Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The headwaters of the Tigris River basin in Iraq is controlled by Turkey due to a series of dams constructed over the last few decades. Since Total Dissolved Solids (TDS) in the Tigris River within Baghdad and downstream cities can reach 1000 mg/L exceeding both drinking water and irrigation guidelines, a hydrodynamic and water quality model, CE-QUAL-W2, of the river was developed to understand how changes in flow affect TDS downstream. A model of 880 km of the Tigris River from Mosul Dam to Kut Barrage including Tharthar Lake was constructed for 2009. Model development was challenging due to a …

Developmental And Sex Modulated Neurological Alterations In Autism Spectrum Disorder, Azeezat Azeez

Dissertations

Autism Spectrum Disorder (ASD) was first described in 1943 by Dr. Leo Kranner in a case study published in The Nervous Child. It is a neurodevelopment disorder, with a range of clinical symptoms. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), used by clinicians to diagnose mental disorders, a child needs to have persistent social deficits, language impairments, and repetitive behaviors, that cannot be explained by neurological damage or intellectual disability. It is known that children diagnosed with ASD are often are developmentally delayed therefore alterations in the typical developmental trajectory should be a major factor in …

Modulation Of Corticospinal Excitability Induced By Paired Associative Stimulation Combined With Movement, Ahmad O. Alokaily

Dissertations

An essential feature of the brain is its capacity to undergo long-lasting morphological or functional changes in response to experiences or trauma. Advances in noninvasive brain stimulation techniques have led to increased interest in understanding neural mechanisms of neuroplasticity at the network level. Paired associative stimulation (PAS) is one of the most commonly used applications for noninvasive brain stimulation because of its clinical potential as an adjuvant rehabilitative intervention. However, the optimal method for incorporating PAS into rehabilitative activities remains unknown. This dissertation explores different approaches to combining PAS with movement and investigates the enhancement of the specificity of conventional …

Modelling In Vitro Dissolution And Release Of Sumatriptan Succinate From Polyvinylpyrrolidone-Based Microneedles Aided By Iontophoresis, James Paul Ronnander

Dissertations

A novel dissolving microneedle array system is developed to investigate permeation of a sumatriptan succinate formulations through the skin aided by iontophoresis. Three formulations consisting of hydrophilic, positively charged drug molecules encapsulated in a water-soluble biologically suitable polymer, polyvinylpyrrolidone (PVP), have been accepted by the U.S. Food and Drug Administration (FDA). The microneedle systems are fabricated with 600 pyramid-shaped needles, each 500 µm tall, on a 0.785-cm² circular array. In vitro transdermal studies with minipig skin and vertical Franz diffusion cells show > 68% permeation of sumatriptan over a 24-hour period. A combination of microneedle and electrical current density ranging …

Effects Of Electro-Osmotic Consolidation Of Clays And Its Improvement Using Ion Exchange Membranes, Lucas Martin

Dissertations

Electro-osmosis is an established method of expediting consolidation of soft, saturated clayey soils compared to commonly used methods, such as preloading with wick drains. In electro-osmotic consolidation a direct current (DC) is applied via inserted electrodes. This causes hydrated ions in the interstitial fluid to migrate to oppositely charged electrodes. Because the clay particles have a negative surface charge, the majority of ions in the interstitial fluid are positively charged. Therefore, the net flow will be towards the negatively charged electrode (cathode), where the water can be removed and thus consolidation is achieved. Certain problems, such as pH changes in …

Improving Boron For Combustion Applications, Kerri-Lee Annique Chintersingh

Dissertations

Boron has received much attention as a potential additive to explosives and propellants due to its high theoretical gravimetric and volumetric heating values. The challenge, however, is that boron particles tend to agglomerate, have lengthy ignition delays and very low combustion rates. Prior research indicates that boron’s long ignition delays are due to its inhibiting naturally occurring oxide layer, impeding the diffusion of reactants for oxidation. For combustion, current studies report that boron particles have two consecutive stages, but the actual reaction mechanism is poorly understood. Despite many years of relevant research, quantitative combustion data on micron-sized boron particles are …

Analyzing Evolution Of Rare Events Through Social Media Data, Xiaoyu Lu

Dissertations

Recently, some researchers have attempted to find a relationship between the evolution of rare events and temporal-spatial patterns of social media activities. Their studies verify that the relationship exists in both time and spatial domains. However, few of those studies can accurately deduce a time point when social media activities are most highly affected by a rare event because producing an accurate temporal pattern of social media during the evolution of a rare event is very difficult. This work expands the current studies along three directions. Firstly, we focus on the intensity of information volume and propose an innovative clustering …

Optimal Sampling Paths For Autonomous Vehicles In Uncertain Ocean Flows, Andrew J. De Stefan

Dissertations

Despite an extensive history of oceanic observation, researchers have only begun to build a complete picture of oceanic currents. Sparsity of instrumentation has created the need to maximize the information extracted from every source of data in building this picture. Within the last few decades, autonomous vehicles, or AVs, have been employed as tools to aid in this research initiative. Unmanned and self-propelled, AVs are capable of spending weeks, if not months, exploring and monitoring the oceans. However, the quality of data acquired by these vehicles is highly dependent on the paths along which they collect their observational data. The …

Roles Of Surfactant And Binary Polymers On Dissolution Enhancement Of Bcs Ii Drugs From Nanocomposites And Amorphous Solid Dispersions, Md Mahbubur Rahman

Dissertations

Drug nanocomposites and amorphous solid dispersions (ASDs) are two major formulation platforms used for the bioavailability enhancement of BCS Class II drugs. The major drawback of nanocomposites is their inability to attain high drug supersaturation during in vitro (<50% relative supersaturation) and in vivo dissolution. On the other hand, formulating an amorphous solid dispersion (ASD) with high drug loading (>20%) that releases drug rapidly, while generating and maintaining high supersaturation over at least three hours is challenging. The goal of this thesis is to develop a fundamental understanding of the impact of anionic surfactants–polymers on in vitro drug release from nanocomposites and ASDs, while addressing the above challenges. To achieve this goal, the following objectives are set: (1) compare griseofulvin …

Data Multiplexing In Vector Acoustic Communication: System Design And Experiments, Erjian Zhang

Dissertations

Acoustic particle velocity channels, which are vector components of the acoustic field, have been recently explored to achieve communication purposes underwater. Vector sensors and transducers that can utilize acoustic particle velocity channels have compact multichannel designs, which are perfect for compact size underwater platforms. In this dissertation, an underwater acoustic multiple-input multiple-output (MIMO) communication system featuring orthogonal frequency division multiplexing (OFDM) and frequency shift keying (FSK) modulation is discussed. By transmitting multiple independent data streams simultaneously over several channels within the same bandwidth, the proposed MIMO system increases the transmission rate. A variety of components of the system such as …

Evaluating The Rheological And Tribological Behaviors Of Coconut Oil Modified With Nanoparticles As Lubricant Additives, Vicente Cortes, Javier A. Ortega

Mechanical Engineering Faculty Publications

In metal-forming processes, the use of lubricants for providing desirable tribological conditions at the tool–workpiece interface is critical to increase the material formability and prolonging tool life. Nowadays, the depletion of crude oil reserves in the world and the global concern in protecting the environment from contamination have renewed interest in developing environmentally-friendly lubricants derived from alternative sources such as vegetable oils. In the present study, the rheological and tribological behavior of coconut oil modified with nanoparticle additives was experimentally evaluated. Two different nanoparticle additives were investigated: Silicon dioxide (SiO₂) and copper oxide (CuO). For the two conditions, …

Low-Cost Open Source Ultrasound-Sensing Based Navigational Support For The Visually Impaired, Aliaksei Petsiuk, Joshua M. Pearce

Michigan Tech Publications, Part 1

Nineteen million Americans have significant vision loss. Over 70% of these are not employed full-time, and more than a quarter live below the poverty line. Globally, there are 36 million blind people, but less than half use white canes or more costly commercial sensory substitutions. The quality of life for visually impaired people is hampered by the resultant lack of independence. To help alleviate these challenges this study reports on the development of a low-cost, open-source ultrasound-based navigational support system in the form of a wearable bracelet to allow people with the lost vision to navigate, orient themselves in their …

Enzymatic Biofuel Cells In A Sandwich Geometry With Compressed Carbon Nanotubes/Enzyme Electrodes & Hybrid Patch Applications, Biao Leng

Dissertations

Enzymatic biofuel cells (EBFCs) convert the chemical energy of biofuels, such as glucose and methanol, into electrical energy by employing enzymes as catalysts. In contrast to conventional fuel cells, EBFCs have a simple membrane-free fuel cell design due to the high catalytic specificity of the enzymes, but the power densities obtained are lower. Although the primary goal of research on EBFCs has been to develop a sustainable power source that can be directly implanted in the human body to power bio-devices, other applications such as the use of a flexible film or fuel cell patch as a wearable power source …