Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2019

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 9271 - 9300 of 10505

Full-Text Articles in Engineering

Internet Of Things: Architecture And Services For Healthcare, Ankita Suvagia Ms. Jan 2019

Internet Of Things: Architecture And Services For Healthcare, Ankita Suvagia Ms.

Dissertations and Theses

Internet of Things (IoT) is a recent prominent collaboration of various technologies that enables spatially distributed devices (“things”) to sense, communicate and share information, thus generating a variety of applications and services in Healthcare. IoT is implemented in multiple domains like Smart city, energy and smart grid, Smart home, weather forecasting, Agriculture, Market and Transportation, Manufacturing and testing industries, Healthcare and many more. IoT serves the purpose of making tasks more efficient and productive and at the same time ensuring quality and reliability. IoT technologies provide an enabling framework for inter-connecting devices, systems, and services that go beyond Machine-to-Machine scenarios …


Gas Hold-Up Measurements In 0.3 M Diameter Bubble Column: Effect Of Electrolytes, Heber Blanco De Brand Jan 2019

Gas Hold-Up Measurements In 0.3 M Diameter Bubble Column: Effect Of Electrolytes, Heber Blanco De Brand

Dissertations and Theses

The present work reports the axial, radial and temporal gas hold-up profiles in a 0.3 m diameter batch bubble column using a pair of Wire Mesh Sensors and six pressure transducers.


A Microfluidic Tissue Array (Μfta) For Personalized Medicine Using Tumor Biopsies, A.H. R. Ahmed Jan 2019

A Microfluidic Tissue Array (Μfta) For Personalized Medicine Using Tumor Biopsies, A.H. R. Ahmed

Dissertations and Theses

Cancer is recognized as a complex disease with both genetic and epigenetic drivers that can vary from one individual to another. While very early research into cancer treated it as a clonal malfunction that could originate from as small as a single deregulated cell, the disease itself manifests itself with several more complexities beyond tumorigenic cells only. The tumor microenvironment itself – from the extracellular matrix to stromal cells - cooperate with tumor cells in a symbiotic manner towards metastatic progression. Clinical studies have provided more information regarding the degree of individualization possible, such that patients with similar genetic makeup …


Designing An On-Demand Dynamic Crowdshipping Model And Evaluating Its Ability To Serve Local Retail Delivery In New York City, Shirin Najaf Abadi Jan 2019

Designing An On-Demand Dynamic Crowdshipping Model And Evaluating Its Ability To Serve Local Retail Delivery In New York City, Shirin Najaf Abadi

Dissertations and Theses

Nowadays city mobility is challenging, mainly in populated metropolitan areas. Growing commute demands, increase in the number of for-hire vehicles, enormous escalation in several intra-city deliveries and limited infrastructure (road capacities), all contribute to mobility challenges. These challenges typically have significant impacts on residents’ quality-of-life particularly from an economic and environmental perspective. Decision-makers have to optimize transportation resources to minimize the system externalities (especially in large-scale metropolitan areas). This thesis focus on the intra-city mobility problems experienced by travelers (in the form of congestion and imbalance taxi resources) and businesses (in the form of last-mile delivery), while taking into consideration …


Designing Particle Tracking Software For A Theoretical Understanding Of Magnetic Janus Particle Aggregation, Thomas W. Long Jan 2019

Designing Particle Tracking Software For A Theoretical Understanding Of Magnetic Janus Particle Aggregation, Thomas W. Long

Dissertations and Theses

Magnetic Janus particles are spherical colloids covered with a thin magnetic cap on one half of their surface. The asymmetric magnetic material gives the particles a magnetic dipole shifted away from the center of mass of the particle. The magnetic dipole either points perpendicular (axially-shifted FexOy caps) or parallel (radially-shifted (Co/Pd)x multilayered particles) to the shift vector. When a magnetic field is applied to a system of magnetic Janus particles, the particles aggregate into chains aligned with the magnetic field. The rate of aggregation is of theoretical and practical interest and the focus of the thesis.

Optically studying samples of …


A Dynamic Risk Management Framework For Water And Environmental Sustainability, Arun Ravindranath Jan 2019

A Dynamic Risk Management Framework For Water And Environmental Sustainability, Arun Ravindranath

Dissertations and Theses

The risks and vulnerabilities facing reservoir systems in river basins shift dynamically over time and space. These risks involve regime changes and shifts, throughout which one observes the transition of water availability from prolonged dry periods to prolonged wet periods. Ensuring reliability of water supply under these hydrological regime shifts involves understanding how these regime shifts can be identified, characterized, and quantified. This dissertation describes a dynamic risk management (DRM) framework for water management at the basin level whose main features are (1) a system of updating risk assessments and policy recommendations on a yearly basis, where the risk assessments …


Development Of Electromagnetic Friction Dampers For Improving Seismic Performance Of Civil Structures, Mohsen Amjadian Jan 2019

Development Of Electromagnetic Friction Dampers For Improving Seismic Performance Of Civil Structures, Mohsen Amjadian

Dissertations and Theses

Energy dissipation is critical to limiting damage to civil structures subjected to extreme natural events such as earthquakes. Friction is one of the most reliable mechanisms of energy dissipation that has been utilized extensively in friction dampers to improve seismic performance of civil structures. Friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably, in spite of the fact that the displacement is generally reduced because of the energy dissipation. This increase in acceleration …


Characterization Of Rare-Earth Doped Thermal Barrier Coatings For Phosphor Thermometry, Quentin Fouliard Jan 2019

Characterization Of Rare-Earth Doped Thermal Barrier Coatings For Phosphor Thermometry, Quentin Fouliard

Electronic Theses and Dissertations

Thermal Barrier Coatings have been extensively used to protect and insulate the metallic components in turbine engines from extreme environments to achieve higher turbine inlet temperatures, resulting in an increase in combined engine cycle efficiency, lowering NOx emissions and fuel consumption. Additionally, as the major failure mechanisms determining lifetime are thermally activated during engine operation, uncertainty in temperature measurements affects lifetime prediction. Early detection of Thermal Barrier Coatings spallation symptoms, associated with local delamination induced temperature changes, can reduce forced engine outages. Further improvements are envisioned with the development of more reliable measurement techniques. For this purpose, Phosphor Thermometry has …


Self-Leadership To Servant Leadership: A Metatheoretical Antecedent To Positive Social, Allen Lloyd Carn Jan 2019

Self-Leadership To Servant Leadership: A Metatheoretical Antecedent To Positive Social, Allen Lloyd Carn

Walden Dissertations and Doctoral Studies

A majority of current leadership programs are failing to deliver a comprehensive approach to leadership development by not providing middle and frontline managers the skills to enhance their potential to develop others. In failing to generate a comprehensive system, animosity towards all types of leadership has been festering for over 40 years as first identified by Greenleaf in 1977. The purpose of the study was to establish a link between the theoretical paradigms of servant leadership and self-leadership using the lens of emotional intelligence to generate an integral leadership development framework. The conceptual framework used Goleman et al.'s version of …


A Quantitative Evaluation Of The Productivity Of The Mercedes-Benz Production System, Derrick Tajuan Shaw Jan 2019

A Quantitative Evaluation Of The Productivity Of The Mercedes-Benz Production System, Derrick Tajuan Shaw

Walden Dissertations and Doctoral Studies

Productivity of automotive manufacturing production systems have been an area of study among researchers since the industrial revolution. Automotive manufacturing production systems that are implemented properly increase productivity in production environments. Researchers have demonstrated that productivity can be improved through modeling the Toyota production system. However, researchers have not established how implementing Mercedes Benz production system (MBPS) impacted Mercedes-Benz cars' productivity between 1999 and 2017. The purpose of this quantitative research study was to examine the effect of implementing the Mercedes-Benz Production System (MBPS). A survey was administered to 35 Mercedes-Benz employees that consisted of operation managers, plant managers, manufacturing …


Public Private Partnership (Ppp): Sustainability In The Context Of Ppp Educational Building Projects, Renuka Rajput Jan 2019

Public Private Partnership (Ppp): Sustainability In The Context Of Ppp Educational Building Projects, Renuka Rajput

Doctoral

This PhD research focuses on and examines the relationship between PPP procurement and sustainability and further aims to establish whether PPP projects can be sustainable with regards to social, enviornmnetal and economic sustainability. The scope of the research is primarily confined to the implementation of construction related sustainability practices within PPPs. It introduces various PPP concepts and critiques the underlying principles for the utilisation of PPP in education sector. This discussion leads to the identification of the core factors common to Sustainability and PPPs and the challenges facing the public and private partners in implementing sustainability in its entirety. In …


Controlled Bubble Dynamics Inside Micropillar Arrays, Faraz Khalil Arya Jan 2019

Controlled Bubble Dynamics Inside Micropillar Arrays, Faraz Khalil Arya

Electronic Theses and Dissertations

Bubble dynamics inside micro domains was manipulated and used to pump liquid. Micropillars were formed inside two 1.5 mm wide and 220 µm high microchannels with a length of 23 mm. One microchannel had three arrays of micropillars with diameters of 40 µm and the other had a single array of micropillars with diameters of 30 µm. An array of five 200 µm by 200 µm heaters was deposited inside these micropillar arrays and was used to control bubble size and trajectory. A sequential power switching of the heaters was used to pump liquid in a desired direction with a …


Stochastic Optimization And Applications With Endogenous Uncertainties Via Discrete Choice Models, Mengnan Chen Jan 2019

Stochastic Optimization And Applications With Endogenous Uncertainties Via Discrete Choice Models, Mengnan Chen

Electronic Theses and Dissertations

Stochastic optimization is an optimization method that solves stochastic problems for minimizing or maximizing an objective function when there is randomness in the optimization process. In this dissertation, various stochastic optimization problems from the areas of Manufacturing, Health care, and Information Cascade are investigated in networks systems. These stochastic optimization problems aim to make plan for using existing resources to improve production efficiency, customer satisfaction, and information influence within limitation. Since the strategies are made for future planning, there are environmental uncertainties in the network systems. Sometimes, the environment may be changed due to the action of the decision maker. …


Guided Autonomy For Quadcopter Photography, Saif Alabachi Jan 2019

Guided Autonomy For Quadcopter Photography, Saif Alabachi

Electronic Theses and Dissertations

Photographing small objects with a quadcopter is non-trivial to perform with many common user interfaces, especially when it requires maneuvering an Unmanned Aerial Vehicle (C) to difficult angles in order to shoot high perspectives. The aim of this research is to employ machine learning to support better user interfaces for quadcopter photography. Human Robot Interaction (HRI) is supported by visual servoing, a specialized vision system for real-time object detection, and control policies acquired through reinforcement learning (RL). Two investigations of guided autonomy were conducted. In the first, the user directed the quadcopter with a sketch based interface, and periods of …


A Critical Assessment On The Resources And Extraction Of Rare Earth Elements From Acid Mine Drainage, Christopher R. Vass Jan 2019

A Critical Assessment On The Resources And Extraction Of Rare Earth Elements From Acid Mine Drainage, Christopher R. Vass

Graduate Theses, Dissertations, and Problem Reports (ETD)

Rare earth elements (REEs) are crucial to many modern products used in both civilian and defense applications. Currently, a reliable supply of these elements is uncertain with the clear majority of REE production and refining occurring predominately in China. Furthermore, domestic ore deposits with commercially attractive concentrations of REEs are uncommon in the United States. As a result, the identification of a domestic supply of these technology metals is essential not only for manufacturing consumer merchandise but also for national security. Recently, one promising source of REEs has been identified: coal and coal-byproducts. One of those is acid mine drainage …


Leveraging Writing And Photography Styles For Drug Trafficker Identification In Darknet Markets, Wei Song Jan 2019

Leveraging Writing And Photography Styles For Drug Trafficker Identification In Darknet Markets, Wei Song

Graduate Theses, Dissertations, and Problem Reports (ETD)

Due to its anonymity, there has been a dramatic growth of underground drug markets hosted in the darknet (e.g., Dream Market and Valhalla). To combat drug trafficking (a.k.a. illicit drug trading) in the cyberspace, there is an urgent need for automatic analysis of participants in darknet markets. However, one of the key challenges is that drug traffickers (i.e., vendors) may maintain multiple accounts across different markets or within the same market.

To address this issue, in this thesis, we propose and develop an intelligent system named uStyle-uID leveraging both writing and photography styles for drug trafficker identification at the first …


Molecular Dynamics Study Of Creep Deformation In Nickel-Based Superalloy, Sabila Kader Pinky Jan 2019

Molecular Dynamics Study Of Creep Deformation In Nickel-Based Superalloy, Sabila Kader Pinky

Graduate Theses/Dissertations

The present study employs molecular dynamics simulations of Ni-based superalloy to investigate the creep behavior under uniaxial compression test. Dislocation dynamics is analyzed for the nickel-based single crystal superalloy with the presence of void and with varying the distribution of gamma-prime phase The results show that multiple-void systems are more prone to yield than single-void systems and single-void systems are more prone to yield than the system without void. From the simulations, it has been determined that the creep mechanism in Ni/Ni3Al is subject to change on the applied stress depending on the distribution of gamma-prime phases change. Dislocation behavior …


N-I-P Nanocrystalline Hydrogenated Silicon Solar Cells With Rf-Magnetron Sputtered Absorbers, Dipendra Adhikari, Maxwell M. Junda, Corey R. Grice, Sylvain X. Marsillac, Robert W. Collins, Nikolas J. Podraza Jan 2019

N-I-P Nanocrystalline Hydrogenated Silicon Solar Cells With Rf-Magnetron Sputtered Absorbers, Dipendra Adhikari, Maxwell M. Junda, Corey R. Grice, Sylvain X. Marsillac, Robert W. Collins, Nikolas J. Podraza

Electrical & Computer Engineering Faculty Publications

Nanocrystalline hydrogenated silicon (nc-Si:H) substrate configuration n-i-p solar cells have been fabricated on soda lime glass substrates with active absorber layers prepared by plasma enhanced chemical vapor deposition (PECVD) and radio frequency magnetron sputtering. The cells with nanocrystalline PECVD absorbers and an untextured back reflector serve as a baseline for comparison and have power conversion efficiency near 6%. By comparison, cells with sputtered absorbers achieved efficiencies of about 1%. Simulations of external quantum efficiency (EQE) are compared to experimental EQE to determine a carrier collection probability gradient with depth for the device with the sputtered i-layer absorber. This incomplete …


The Educational Value Of Modelling Complex Thermodynamic Systems With System Dynamics Software, Stephen Crown, Constantine Tarawneh Jan 2019

The Educational Value Of Modelling Complex Thermodynamic Systems With System Dynamics Software, Stephen Crown, Constantine Tarawneh

Mechanical Engineering Faculty Publications

The solution of problems involving complex thermodynamic systems often occupies much of a students' time and can be a distraction from them developing a clear understanding of system components, interaction of subsystems, modelling simplifications and assumptions, and design optimization. Refocusing students on the fundamental concepts of thermal systems design and analysis is possible with the introduction of system modelling software that carries some of the load of repetitive calculation required for complex systems. Models of thermodynamic systems encountered in an advanced undergraduate thermodynamics course were developed by students (some provided to students) to solve homework problems of complex steam power …


Fabrication Of Ultra-Fine Cathodes For Cold-Field Emission, Srujana Valluri Jan 2019

Fabrication Of Ultra-Fine Cathodes For Cold-Field Emission, Srujana Valluri

Graduate Research Theses & Dissertations

This thesis discusses the different fabrication steps involved in producing ultra-fine cathodes that are suitable for cold field emission. A four-step nanofabrication process has been developed to obtain the cathodes with tip diameters ranging from 10nm to 20 nm. First, a mask is patterned on a 2-inch silicon wafer using monodisperse 1.18µm silica spheres. These particles are self-assembled using vortex-flow enabled assembly technique to form close-packed monolayers. Then the silicon is etched using a reactive ion etching technique. An inductively coupled plasma etcher is used to perform anisotropic and isotropic etching. The etching recipes used are chosen such that they …


Tools For Understanding Static Structure Factors And Their Application To Simulations Of Liquids, Travis Mackoy Jan 2019

Tools For Understanding Static Structure Factors And Their Application To Simulations Of Liquids, Travis Mackoy

Graduate Research Theses & Dissertations

Molecular dynamics (MD) simulations can be used to compute static structure factors (��(��)) and provide an interpretation of the underlying periodic atomic ordering. MD simulations complement experimentally measured ��(��) by allowing qualitative assignment of peaks to various ordering, such as cation-anion ordering in ionic liquids, via decomposition of ��(��) into partial ��(��). Here we present a method for classifying interatomic distances that allows for quantitative peak assignment and visualization of atoms that contribute most to each peak in calculated ��(��) for soft materials. The method is illustrated by investigating ��(��) for the ionic liquid 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (C4C1pyrrTFSI), which shows two …


Numerical And Experimental Validation For The Optimization Of Directed Energy Deposition Processing Parameters, Luis Nunez Jan 2019

Numerical And Experimental Validation For The Optimization Of Directed Energy Deposition Processing Parameters, Luis Nunez

Graduate Research Theses & Dissertations

In order to capitalize on the cost effectiveness of Metal Additive Manufacturing (MAM) it is critical to understand how to build components with consistency and high quality. Directed Energy Deposition (DED) is a MAM method for creating parts layer by layer through the use of a moving heat source and powder material inserted into the melt pool generated on the substrate. DED like most MAM processes are highly complex due to the rapid thermal gradients experienced during processing. These thermal gradients are determined by a variety of processing parameters which include laser power, powder feed rate, travel speed, layer height …


The Social Presence Of Jibo, Parisa Farhadi Jan 2019

The Social Presence Of Jibo, Parisa Farhadi

Graduate Research Theses & Dissertations

This research is an attempt to investigate how a social robot is perceived by users at the first encounter. And to find out whether a social robot like Jibo is understood merely as a kind of a technological object or a social entity. Previous studies in Human-Robot Interaction have considered social presence as a mediator in users’ social responses toward robots; however, the focus of this study is the social presence itself and investigates whether Jibo produces a sense of presence during initial encounters. To this end, the current study examines individuals’ perceptions of and responses to Jibo. Participants (N=8) …


Characterization Of Boron/Iron-Oxide Core/Shell Structure For Boron Neutron Capture Therapy By Stem/Eels-Xeds And Mössbauer Spectroscopy, Mason Douglas Hayward Jan 2019

Characterization Of Boron/Iron-Oxide Core/Shell Structure For Boron Neutron Capture Therapy By Stem/Eels-Xeds And Mössbauer Spectroscopy, Mason Douglas Hayward

Graduate Research Theses & Dissertations

Boron/iron-oxide core/shell structured nanoparticles were characterized for application in boron neutron capture therapy (BNCT). BNCT is a cancer treatment method using the ability of boron to absorb thermal neutrons and a proposed drug delivery system utilizing an external magnetic field to direct the boron nanoparticles to targeted cancer sites and to extract the used nanoparticles after treatment. Boron nanoparticles were magnetically functionalized by encapsulating with an iron oxide shell. As such the exact composition, size distribution and oxidation states of the core/shell structures can affect treatment efficacy. Characterization was done by electron energy loss spectroscopy (EELS) and x-ray energy dispersive …


Performance Of Plunge Depth Control Methods During Friction Stir Welding, Jinyoung Yoon, Cheolhee Kim, Sehun Rhee Jan 2019

Performance Of Plunge Depth Control Methods During Friction Stir Welding, Jinyoung Yoon, Cheolhee Kim, Sehun Rhee

Mechanical and Materials Engineering Faculty Publications and Presentations

Friction stir welding is a preferred solid state welding process for Al/Fe joints, and in friction stir lap welding, the plunge depth is the most critical parameter for joint strength. We compared three plunge depth control methods, namely conventional position control, offset position control, and deflection compensation control in the friction stir lap welding of 3 mm-thick Al 5083-O alloy over 1.2 mm-thick DP 590 steel. The desired plunge depth was 0.2 mm into the steel sheet. However, the pin did not reach the steel surface under conventional position control due to deflection of the vertical axis of the welding …


Simulation To Fabrication—Understanding The Effect Of Niaucu Alloy Catalysts For Controlled Growth Of Graphene At Reduced Temperature, Huahan Zhan, Bin Jiang, Otto Zietz, Samuel Olson, Jun Jiao Jan 2019

Simulation To Fabrication—Understanding The Effect Of Niaucu Alloy Catalysts For Controlled Growth Of Graphene At Reduced Temperature, Huahan Zhan, Bin Jiang, Otto Zietz, Samuel Olson, Jun Jiao

Mechanical and Materials Engineering Faculty Publications and Presentations

It is a significant challenge to grow large-scale, high quality, monolayer graphene at low temperature for the applications in industry, especially for the complementary metal oxide semiconductor fabrication process. To overcome this difficulty, we simulated the decomposition of acetylene (C2H2) on (100) surfaces of primarily nickel (Ni) catalysts with small mol fractions of gold (Au) and copper (Cu), using a 4 × 4 × 4 periodic supercell model. Based on the calculation of the reaction energies to decompose the C-H or C≡C bonds on different catalyst surfaces, a differential energy is proposed to clearly scale the decomposition difficulties such that …


Modeling Of Optimized Neuro-Fuzzy Logic Based Active Vibration Control Method For Automotive Suspension, Mohammad Adom Safiullah Jan 2019

Modeling Of Optimized Neuro-Fuzzy Logic Based Active Vibration Control Method For Automotive Suspension, Mohammad Adom Safiullah

Masters Theses

In this thesis, an active vibration control system was developed. The control system was developed and tested using a quarter car model of an adaptive suspension system. For active vibration control, an actuator was implemented in addition to the commonly used passive spring damper system. Due to nature of unpredictability of force required two different fuzzy inference system (FIS) were developed for the actuator. First a sequential fuzzy set was built, that resulted lower vertical displacement compared to basic damper spring model, but system had limited effect with disturbances of higher magnitude and continuous vibrations (rough road). To improve the …


A Kinetic Monte Carlo Study Of Mesoscopic Perovskite Solar Cell Performance Behavior, Behzad Bahrami Jan 2019

A Kinetic Monte Carlo Study Of Mesoscopic Perovskite Solar Cell Performance Behavior, Behzad Bahrami

Electronic Theses and Dissertations

Perovskite solar cells have received considerable attention in recent years due to their low processing cost and high energy conversion efficiency. However, the mechanisms of perovskite solar cell performance are not fully understood. Models based on probabilistic and statistical approaches can be used to simulate, optimize, and predict perovskite solar cell photovoltaic performance, and they can also guide experimental processing and fabrication conditions to achieve higher photovoltaic efficiency. This work developed a 3D model based on the kinetic Monte Carlo (KMC) approach to simulate 3D morphology of perovskite-based solar cells and predict their photovoltaic performance. The model incorporated the physical …


Static Load Bolted Joint Elastic Resilience Testing Methodology, Paul Melino Jan 2019

Static Load Bolted Joint Elastic Resilience Testing Methodology, Paul Melino

Electronic Theses and Dissertations

Elastic resilience is the ratio of deformation over force an object experiences when under stress. Knowing the how much the bolt and clamped part deform under load is critical when determining fasteners for a bolted joint. VDI 2230 is the internationally recognized bolt sizing standard and contains the equations used to determine each of the bolted joint component’s resilience as well as values for embedment estimates based on component surface roughness. Embedment is the local plastic deformation due to uneven contact over the contact planes of a bolt-clamped interface (Bolt head to plate, plate to plate, plate to nut, and …


The Effect Of Curing And Zirconium Content On The Wettability And Structure Of A Silicate Hybrid Sol-Gel Material, Emma Machugh, Maikki Cullen, Alicja Kaworek, Brendan Duffy, Mohamed Oubaha Jan 2019

The Effect Of Curing And Zirconium Content On The Wettability And Structure Of A Silicate Hybrid Sol-Gel Material, Emma Machugh, Maikki Cullen, Alicja Kaworek, Brendan Duffy, Mohamed Oubaha

Articles

Functional hybrid sol-gel coatings have been developed for numerous applications with a wide range of wettabilities. This study proposes to investigate the relationship between the structure and the wetting properties of a zirconium modified silicate hybrid sol-gel coating. The structures of the coatings were altered by varying the content of zirconium, and the curing process, while keeping the sol-gel preparation conditions identical. The structure of the materials was characterized by FTIR, 29Si NMR and SEM. The thermal properties and the wettability are identified by DSC and contact angle measurements, respectively. By corroborating the structural and wettability analyses, it is shown …