Engineering Commons^™

3d Bioprinting Of Stem Cells And Polymer/Bioactive Glass Composite Scaffolds For Bone Tissue Engineering, Caroline Murphy, Krishna Kolan, Wenbin Li, Julie A. Semon, D. E. Day, Ming-Chuan Leu

Biological Sciences Faculty Research & Creative Works

A major limitation of using synthetic scaffolds in tissue engineering applications is insufficient angiogenesis in scaffold interior. Bioactive borate glasses have been shown to promote angiogenesis. There is a need to investigate the biofabrication of polymer composites by incorporating borate glass to increase the angiogenic capacity of the fabri-cated scaffolds. In this study, we investigated the bioprinting of human adipose stem cells (ASCs) with a polycaprolac-tone (PCL)/bioactive borate glass composite. Borate glass at the concentration of 10 to 50 weight %, was added to a mixture of PCL and organic solvent to make an extrudable paste. ASCs suspended in Matrigel …

New Epoch For Community Co-Operatives In Ireland: Factors Required For Their Implementation, Gerard Doyle

Conference Papers

Over the past century co-operatives have made a significant contribution to alleviating many economic and social crises Irish society has encountered. For example, producer co-operatives have enabled farmers to gain a superior price for their produce rather than dealing with middlemen (Tucker, 1983). In the 1950s the credit union movement enabled thousands of families’ access to affordable credit (Quinn, 1999). Since the 1970s, Ireland has experienced many crises including mass unemployment, emigration and housing shortages. It was also affected by fuel rationing, emanating from our over-reliance on imported fossil fuels combined with the oil crisis of 1973 and 1977. In …

Strengthening The Development Of The Short-Rotation Plantations Bioenergy Sector: Policy Insights From Six European Countries, Carlos Parra-Lopez, Martin Holley, Kevin Lindegaard, Samir Sayadi, Gonzalo Esteban-Lopez, Victor Duran-Zuazo, Christoph Knauer, Hans-Georg Von Engelbrechten, Ralf Winterber, Annika Henriksson, Annette Lamley, Anders Nylander, Susanne Paulrud, Pauline Leonard, Patrick Daly, Lukasz Drzewaszewski, Wojciech Rzewuski

Articles

This paper, based on a participatory methodological framework involving expert stakeholders and researchers from six European countries (Germany, Ireland, Poland, Spain, Sweden and UK), analyses the priority issues for the development of short-rotation plantations (SRP), and proposes a series of policy strategies to strengthen this development. The results indicate that there is a lack of awareness of the multifaceted benefits of SRP at the level of farmers, policy makers and public authorities. More research is required to put a value on the multifunctionality of SRP and justify its public support. Small-scale projects using established technologies are also required with energy …

A New Formulation Of Time Boundary Integral Equation For Acoustic Wave Scattering In The Presence Of A Uniform Mean Flow, Fang Q. Hu, Michelle E. Pizzo, Douglas M. Nark

Mathematics & Statistics Faculty Publications

It has been well-known that under the assumption of a constant uniform mean flow, the acoustic wave propagation equation can be formulated as a boundary integral equation, in both the time domain and the frequency domain. Compared with solving partial differential equations, numerical methods based on the boundary integral equation have the advantage of a reduced spatial dimension and, hence, requiring only a surface mesh. However, the constant uniform mean flow assumption, while convenient for formulating the integral equation, does not satisfy the solid wall boundary condition wherever the body surface is not aligned with the uniform mean flow. In …

Well Integrity Assessment Of Monitoring Wells At An Active Co2-Eor Flood, Andrew Duguid, Boyun Guo, Runar Nygaard

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Assessment of well integrity has become more important for CCS and CO₂-EOR as it has become apparent that wells represent the most likely migration pathway for CO₂ to leave a CCS storage unit or a CO₂-EOR reservoir. Although wells represent a migration pathway, they are also the best vehicle for employing technology monitoring CO₂ injection and storage. This contradiction of being a potential migration path and key monitoring technology leads to a need to understand how monitoring wells may be similar or different in comparison to other types of wells with respect to migration …

Modelling And Simulation Of Grid Connected Lithium-Ion Battery Using Homer, Shantu Ghose, Adel El-Shahat

Electrical & Computer Engineering: Faculty Publications

In order to improve battery technology understanding the capacity fading method in batteries is very important. Battery models can be used to predict their behavior under various operating conditions. Here we proposed a simple dynamic model of lithium-ion battery with MATLAB/Simulink to observe the output characteristics of this energy storage device. Dynamic simulations are carried out, including the observation of the changes in battery terminal output voltage under different discharging/charging, temperature and cycling conditions. The simulation studies are presented for proving that the model is useful. At the end we will use this energy storage device to interconnect with HOMER. …

Influence Of Small Particles Inclusion On Selective Laser Melting Of Ti-6al-4v Powder, Haijun Gong, J. J.S. Dilip, Li Yang, Chong Teng, Brent Stucker

Manufacturing Engineering: Faculty Publications (2015-2023)

The particle size distribution and powder morphology of metallic powders have an important effect on powder bed fusion based additive manufacturing processes, such as selective laser melting (SLM). The process development and parameter optimization require a fundamental understanding of the influence of powder on SLM. This study introduces a pre-alloyed titanium alloy Ti-6Al-4V powder, which has a certain amount of small particles, for SLM. The influence of small particle inclusion is investigated through microscopy of surface topography, elemental and microstructural analysis, and mechanical testing, compared to the Ti-6Al-4V powder provided by SLM machine vendor. It is found that the small …

Assessing The Usefulness Of Different Feature Sets For Predicting The Comprehension Difficulty Of Text, Brian Mac Namee, John D. Kelleher, Noel Fitzpatrick

Conference papers

Within English second language acquisition there is an enthusiasm for using authentic text as learning materials in classroom and online settings. This enthusiasm, however, is tempered by the difficulty in finding authentic texts at suitable levels of comprehension difficulty for specific groups of learners. An automated way to rate the comprehension difficulty of a text would make finding suitable texts a much more manageable task. While readability metrics have been in use for over 50 years now they only capture a small amount of what constitutes comprehension difficulty. In this paper we examine other features of texts that are related …

Analysing The Behaviour Of Online Investors In Times Of Geopolitical Distress: A Case Study On War Stocks, James Usher, Pierpaolo Dondio

Conference papers

In this paper we analyse how the behavior of an online financial community in time of geopolitical crises. In particular, we studied the behaviour, composition and communication patterns of online investors before and after a military geopolitical event. We selected a set of 23 key-events belonging to the 2003 US-led invasion of Iraq, the Arab Spring and the first period of the Ukraine crisis. We restricted our study to a set of eight so called military stocks, which are US-manufacturing companies active in the defence sector. We studied the resilience of the community to information shocks by comparing the community …

A Holistic Risk-Oriented Framework For Port Infrastructure Adaption To Climate Change, Kana Nkasanga Patrick Mutumbo

World Maritime University Ph.D. Dissertations

This research is the first attempt in developing a broad-based qualitative tool for assessing climate risk in ports and building resilience. In order to demonstrate the applicability of the conceptual tool, the new Durban Dig-Out Port (DDOP) under development in the City of Durban (South Africa) is used for case study. Central to this research is the building of widespread industry recognition of the need to factor climate change into decision making at early stages of port development.

The recent significant shift toward supply chain management and customer orientation practices calls for the need to assess the effectiveness of port …

Super-Strong Materials For Temperatures Exceeding 2000 ⁰C, Laura Silvestroni, Hans Joachim Kleebe, William Fahrenholtz, Jeremy Lee Watts

Materials Science and Engineering Faculty Research & Creative Works

Ceramics based on group IV-V transition metal borides and carbides possess melting points above 3000⁰C, are ablation resistant and are, therefore, candidates for the design of components of next generation space vehicles, rocket nozzle inserts, and nose cones or leading edges for hypersonic aerospace vehicles. As such, they will have to bear high thermo-mechanical loads, which makes strength at high temperature of great importance. While testing of these materials above 2000⁰C is necessary to prove their capabilities at anticipated operating temperatures, literature reports are quite limited. Reported strength values for zirconium diboride (ZrB₂) ceramics can exceed 1 GPa …

Control Of Columnar To Equiaxed Transition In Solidification Macrostructure Of Austenitic Stainless Steel Castings, Semen Naumovich Lekakh, Ronald J. O'Malley, Mark C. Emmendorfer, Brenton Hrebec

Materials Science and Engineering Faculty Research & Creative Works

Solidification macrostructure is of great importance for the properties and the quality of castings made from austenitic grade stainless steels (ASS) because there are limited options to change as-cast macrostructure in the solid condition. A typical cast macrostructure of ASS has a fine surface chilled zone followed by an elongated dendrite zone, columnar to equiaxed transition (CET) zone, and centrally located equiaxed crystals. Several castings from ASS were produced to determine the effects of casting geometry, chilling, and grain refinement on CET. The transient thermal field in solidified heavy castings was simulated and used to determine an isotherm velocity (V) …

Omni-Directional Infrared 3d Reconstruction And Tracking Of Human Targets, Emrah Benli

Theses and Dissertations

Omni-directional (O-D) infrared (IR) vision is an effective capability for mobile systems in robotics, due to its advantages: illumination invariance, wide field-of-view, ease of identifying heat-emitting objects, and long term tracking without interruption. Unfortunately, O-D IR sensors have low resolution, low frame rates, high cost, sensor noise, and an increase in tracking time. In order to overcome these disadvantages, we propose an autonomous system application in indoor scenarios including 1) Dynamic 3D Reconstruction (D3DR) of the target view in real time images, 2) Human Behavior-based Target Tracking from O-D thermal images, 3) Thermal Multisensor Fusion (TMF), and 4) Visual Perception …

Electrospraying Extracellular Matrix To Form Nanoparticles, Patrick Link

Theses and Dissertations

Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of death worldwide. Alveolar wall destruction is a significant contributor to COPD. Inflammatory macrophages are a major source of the Extracellular Matrix (ECM) proteolysis. ECM breakdown causes air to get trapped in the alveoli, obstructing airflow. One step in curing COPD may be to convert inflammatory to pro-regenerative macrophages. Recently, decellularized ECM scaffolds have shown the ability to induce a pro-regenerative phenotype.

Yet these scaffolds are incapable for reaching the alveolar region of the lungs. To reach the alveolar region particles need a diameter of 1-5 μm or smaller than 300 …

Preparation And Application Of Catalysts For The Stereospecific Reduction And Photooxygenation Of Olefins In Continuous Operations: A Novel Method For The Production Of Artemisinin, Daniel C. Fisher

Theses and Dissertations

Over the last two centuries, the discovery and application of catalysts has had a substantial impact on how and what chemicals are produced.Given their broad significance, our group has focused on developing new catalyst systems that are recoverable and reusable, in an attempt to reduce concomitant costs.

Our efforts have centered on constructing a recyclable chiral heterogeneous catalyst capable of effecting asymmetric hydrogenations of olefins with high stereoselectivity. A class of phosphinoimidazoline ligands, developed by researchers at Boehringer-Ingelheim, known as BIPI ligands, have proven efficacious in the asymmetric reduction of alkenes. However, these chiral ligands are homogeneous and coordinated to …

Strain Distribution In The Porcine Lumbar Laminae Under Asymmetric Loading, Colin Bright, Stephen Tiernan, Fiona Mcevoy, Patrick Kiely

Conference Papers

If the articular facets of the vertebra grow in an asymmetric manner, the developed geometry causes an asymmetry of loading. When the loading environment is altered by way of increased activity, the likelihood of acquiring a stress fracture may be increased. The combination of geometric asymmetry and increased activity is hypothesised to be the precursor to the stress fracture under investigation in this study, spondylolysis. This vertebral defect is an acquired fracture with 7% prevalence in the paediatric population. This value increases to 21% among athletes who participate in hyperextension sports. Tests were carried out on porcine lumbar vertebrae, on …

Reversible Control Of The Magnetization Of Spinel Ferrites Based Electrodes By Lithium-Ion Migration, Guodong Wei, Lin Wei, Dong Wang, Yanxue Chen, Yufeng Tian, Shishen Yan, Liangmo Mei, Jun Jiao

Mechanical and Materials Engineering Faculty Publications and Presentations

Lithium-ion (Li-ion) batteries based on spinel transition-metal oxide electrodes have exhibited excellent electrochemical performance. The reversible intercalation/deintercalation of Li-ions in spinel materials enables not only energy storage but also nondestructive control of the electrodes’ physical properties. This feature will beneft the fabrication of novel Li-ion controlled electronic devices. In this work, reversible control of ferromagnetism was realized by the guided motion of Li-ions in MnFe₂O₄ and γ-Fe₂O₃ utilizing miniature lithium-battery devices. The in-situ characterization of magnetization during the Li-ion intercalation/deintercalation process was conducted, and a reversible variation of saturation magnetization over 10% was observed …

Design And Modeling For Dc Nanogrids, Ormond D. Castle

College of Graduate Studies: Theses & Dissertations

Smart grids were constructed as a means of communication to the electric grid through computer and other information technologies. This line of communication acts as gauge for a more accurate reading of power consumed. A nano grid is a model version of a smart grid with the ability to function as separate power generator. Such feature allows for this grid to power single loads and apply for special applications. A DC-DC converter was designed to apply to a nano grid which is a form of a smart grid. The converter was a single-input-multi-output converter which is taking one dc voltage …

Intrusion Detection For Smart Grid Communication Systems, Brycent Chatfield

College of Graduate Studies: Theses & Dissertations

Transformation of the traditional power grid into a smart grid hosts an array of vulnerabilities associated with communication networks. Furthermore, wireless mediums used throughout the smart grid promote an environment where Denial of Service (DoS) attacks are very effective. In wireless mediums, jamming and spoofing attack techniques diminish system operations thus affecting smart grid stability and posing an immediate threat to Confidentiality, Integrity, and Availability (CIA) of the smart grid. Intrusion detection systems (IDS) serve as a primary defense in mitigating network vulnerabilities. In IDS, signatures created from historical data are compared to incoming network traffic to identify abnormalities. In …

Secure Cloud Controlled Software Defined Radio Network For Bandwidth Allocation, Isaac J. Cushman

College of Graduate Studies: Theses & Dissertations

The purpose of this research is to investigate the impact of mobility of wireless devices for opportunistic spectrum access and communications using National Instrument Universal Software Radio Peripherals devices. The overall system utilizes software defined radio networks for frequency allocation, cloud connectivity to maintain up-to-date information, and moving target defense as a security mechanism. Each USRP device sends its geolocation to query the spectrum database for idle channels. The cloud cluster was designed for complex data storage and allocation using a smart load balancer to offer ultra-security to users. This project also explores the advantages of data protection and security …

Study And Implementation Of Wideband Bow-Tie Antennas, Md Rakibul Islam

College of Graduate Studies: Theses & Dissertations

Demand for multifunctional electronic devices is increasing in modern wireless communication systems. As the antenna plays a vital role in wireless communication, the need to design antennas which will provide better performance and more reliable communication is growing. In this thesis, innovative designs for antennas with wideband characteristic have been proposed to meet the demands of current multi-functional wireless communication systems. First, this thesis explores the design of a wideband pattern reconfigurable antenna with steady realized gain over the operating bandwidth. Another novel design of this thesis work is a highly directive wideband Yagi antenna. Finally, a two-planar structured CPLPDA …

Ego-Localization Navigation For Intelligent Vehicles Using 360° Lidar Sensor For Point Cloud Mapping, Tyler Naes

College of Graduate Studies: Theses & Dissertations

With its prospects of reducing vehicular accidents and traffic in highly populated urban areas by taking the human error out of driving, the future in automobiles is leaning towards autonomous navigation using intelligent vehicles. Autonomous navigation via Light Detection And Ranging (LIDAR) provides very accurate localization within a predefined, a priori, point cloud environment that is not possible with Global Positioning System (GPS) and video camera technology. Vehicles may be able to follow paths in the point cloud environment if the baseline paths it must follow are known in that environment by referencing objects detected in the point cloud …

Audio-Based Productivity Forecasting Of Construction Cyclic Activities, Chris A. Sabillon

College of Graduate Studies: Theses & Dissertations

Due to its high cost, project managers must be able to monitor the performance of construction heavy equipment promptly. This cannot be achieved through traditional management techniques, which are based on direct observation or on estimations from historical data. Some manufacturers have started to integrate their proprietary technologies, but construction contractors are unlikely to have a fleet of entirely new and single manufacturer equipment for this to represent a solution. Third party automated approaches include the use of active sensors such as accelerometers and gyroscopes, passive technologies such as computer vision and image processing, and audio signal processing. Hitherto, most …

Thermal Performance Of A Double-Pipe Heat Exchanger With A Koch Snowflake Fractal Design, Anton Gomez

College of Graduate Studies: Theses & Dissertations

Double-pipe heat exchangers are the simplest type of heat exchanger and are widely utilized in industrial applications. The effectiveness of double-pipe heat exchangers can be increased by using various heat transfer enhancement techniques. Passive heat transfer enhancement methods are desirable as they do not require moving components and are easy to manufacture and maintain. The focus of this study is to implement a passive heat transfer enhancement method and to investigate how thermal performance is impacted. Specifically, the inner pipe in a heat exchanger will be modified to have a cross-section in accordance with the Koch snowflake fractal pattern. The …

Performance Analysis Of Massive Mimo System With Quality Of Service Requirements And Precoding Techniques, Kishan Neupane

College of Graduate Studies: Theses & Dissertations

The massive MIMO is a promising technology for future 5G wireless communication systems to provide high spectrum efficiency. The use of a very large number of antennas for both transmission and reception is an intuitive approach to boost the system capacity and enhance the link reliability. The main requirement of future wireless systems are high throughput, serving many users simultaneously with optimal energy consumption. In the first part of the thesis, we proposed a novel algorithm for secrecy rate analysis of massive MIMO with QoS requirement by adapting the transmit signal vector and power of user using game theory. The …

On A Time Domain Boundary Integral Equation Formulation For Acoustic Scattering By Rigid Bodies In Uniform Mean Flow, Fang Q. Hu, Michelle E. Pizzo, Douglas M. Nark

Mathematics & Statistics Faculty Publications

It has been well-known that under the assumption of a uniform mean flow, the acoustic wave propagation equation can be formulated as a boundary integral equation. However, the constant mean flow assumption, while convenient for formulating the integral equation, does not satisfy the solid wall boundary condition wherever the body surface is not aligned with the assumed uniform flow. A customary boundary condition for rigid surfaces is that the normal acoustic velocity be zero. In this paper, a careful study of the acoustic energy conservation equation is presented that shows such a boundary condition would in fact lead to source …

Evaluating Outer Segment Length As A Surrogate Measure Of Peak Foveal Cone Density, Melissa A. Wilk, Brandon M. Wilk, Christopher S. Langlo, Robert F. Cooper, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Adaptive optics (AO) imaging tools enable direct visualization of the cone photoreceptor mosaic, which facilitates quantitative measurements such as cone density. However, in many individuals, low image quality or excessive eye movements precludes making such measures. As foveal cone specialization is associated with both increased density and outer segment (OS) elongation, we sought to examine whether OS length could be used as a surrogate measure of foveal cone density. The retinas of 43 subjects (23 normal and 20 albinism; aged 6–67 years) were examined. Peak foveal cone density was measured using confocal adaptive optics scanning light ophthalmoscopy (AOSLO), and OS …

Diffusion Tensor Imaging Correlates With Short-Term Myelopathy Outcome In Patients With Cervical Spondylotic Myelopathy, Aditya Vedantam, Avinash Rao, Shekar N. Kurpad, Michael B. Jirjis, Gerald Eckardt, Brian D. Schmit, Marjorie C. Wang

Biomedical Engineering Faculty Research and Publications

Objective

To determine if spinal cord diffusion tensor imaging indexes correlate with short-term clinical outcome in patients undergoing elective cervical spine surgery for cervical spondylotic myelopathy (CSM).

Methods

A prospective consecutive cohort study was performed in patients undergoing elective cervical spine surgery for CSM. After obtaining informed consent, patients with CSM underwent preoperative T2-weighted magnetic resonance imaging and diffusion tensor imaging of the cervical spine. Fractional anisotropy (FA) values at the level of maximum cord compression and at the noncompressed C1-2 level were calculated on axial images. We recorded the modified Japanese Orthopaedic Association (mJOA) scale, Neck Disability Index, and …

Lessons Learned From A 10-Year Collaboration Between Biomedical Engineering And Industrial Design Students In Capstone Design Projects, Jay R. Goldberg, Pascal Malassigné

Biomedical Engineering Faculty Research and Publications

Engineers and industrial designers have different approaches to problem solving. Both place heavy emphasis on identification of customer needs, manufacturing methods, and prototyping. Industrial designers focus on aesthetics, ergonomics, ease of use, manufacturing methods, and the user’s experience. They tend to be more visual and more concerned with the interaction between users and products. Engineers focus on functionality, performance requirements, analytical modeling, and design verification and validation. They tend to be more analytical and more concerned with the design of internal components and product performance. Engineers and industrial designers often work together on project teams in industry. Collaboration between the …

Limb Stabilization In Older Adults And Chronic Stroke Survivors: A Pilot Study, Raymond C. Doudlah, Robert A. Scheidt, Aaron J. Suminski

Biomedical Engineering Faculty Research and Publications

Visual fidelity influences many aspects of daily living, including stabilizing wrist movements against environmental perturbations. Here, we present a pilot investigation to determine how visual feedback impacts wrist stabilization for populations with age related declines in motor function and chronic stroke. To quantify these interactions, behavioral performance and local brain activation were observed during a task requiring stabilization of the wrist against constant and stochastic extensor torque perturbations. All subjects were better able to stabilize their wrist when veridical visual feedback of their limb was provided. Examination of the neural activation maps in the Control and Aging populations revealed patterns …