Engineering Commons^™

Molecular Dynamics Simulation Of Polymer Nanocomposites In Extreme Environments, Farzin Rahmani

Electronic Theses and Dissertations

In this dissertation, lower length scale phenomena associated with the responses of hybrid materials to harsh and extreme environments were studied. The goal of this research was to reveal the underlying mechanisms of damage mitigation in these materials and the role that interface, and relevant material component interactions play in the overall material response. First, the thermal decomposition behavior of a technologically important material system, i.e., pristine graphene (PG) and graphene oxide (GO) reinforced poly(ethylene oxide) (PEO), was investigated using a reactive molecular dynamics simulation methodology. The simulations were performed in both non-isothermal (dynamic gravimetric) and isothermal modes of decomposition. …

Multiobjective Reservoir Optimization Using Genetic Algorithm, Seyma Tiryakioglu

Electronic Theses and Dissertations

This thesis investigates the optimization of energy generation in a multipurpose reservoir. The objective functions and the constraints for the multiobjective optimization of reservoir operation for maximization of energy production involve the solution of a set of nonlinear equations governing pressure flow in penstock and turbine system and the hydropower generation. The hydropower generation also requires operational rules that define how the reservoir storage volume must be used at different storage levels. For these reasons, the present thesis uses genetic algorithm (GA) functions available in Matlab to perform the multiobjective optimization of hydropower energy production. Multiobjective optimization is based on …

Electrotransfer Of Different Control Plasmids Elicits Different Antitumor Effectiveness In B16.F10 Melanoma, Masa Bosnjak, Tanjo Jesenko, Urska Kamensek, Gregor Sersa, Jaka Lavrencak, Loree Heller, Maja Cemazar

Bioelectrics Publications

Several studies have shown that different control plasmids may cause antitumor action in different murine tumor models after gene electrotransfer (GET). Due to the differences in GET protocols, plasmid vectors, and experimental models, the observed antitumor effects were incomparable. Therefore, the current study was conducted comparing antitumor effectiveness of three different control plasmids using the same GET parameters. We followed cytotoxicity in vitro and the antitumor effect in vivo after GET of control plasmids pControl, pENTR/U6 scr and pVAX1 in B16.F10 murine melanoma cells and tumors. Types of cell death and upregulation of selected cytosolic DNA sensors and cytokines were …

Photoluminescence From Gan Co-Doped With C And Si, Mykhailo Vorobiov

Theses and Dissertations

This thesis devoted to the experimental studies of yellow and blue luminescence (YL and BL relatively) bands in Gallium Nitride samples doped with C and Si. The band BL_C was at first observed in the steady-state photoluminescence spectrum under high excitation intensities and discerned from BL1 and BL2 bands appearing in the same region of the spectrum. Using the time-resolved photoluminescence spectrum, we were able to determine the shape of the BL_C and its position at 2.87 eV. Internal quantum efficiency of the YL band was estimated to be 90\%. The hole capture coefficient of the BL_{C …}

Design Of Dna Strand Displacement Based Circuits, Aby Konampurath George

Wayne State University Dissertations

DNA is the basic building block of any living organism. DNA is considered a popular candidate for future biological devices and circuits for solving genetic disorders and several other medical problems. With this objective in mind, this research aims at developing novel approaches for the design of DNA based circuits. There are many recent developments in the medical field such as the development of biological nanorobots, SMART drugs, and CRISPR-Cas9 technologies. There is a strong need for circuits that can work with these technologies and devices. DNA is considered a suitable candidate for designing such circuits because of the programmability …

Influential Factors In Consumer's Adoption Of Innovative Products, Mahdokht Kalantari

Wayne State University Dissertations

This dissertation addresses the challenges involved with the process of diffusion of innovations in the contexts of innovative educational materials and technological innovations.

Chapters 2 and 3 discuss building and using Online Brand Communities (OBCs) to disseminate innovative math educational materials. OBCs are known to be important platforms where consumers can communicate with the brand as well as other consumers. Through the effective use of these platforms, brands could accelerate the process of diffusion of their innovations. However, OBCs will not survive if consumers do not get engaged and participate in these communities. The purpose of this section of the …

The Impact Of Machine Learning Algorithms On Benchmarking Process In Healthcare Service Delivery, Egbe-Etu Emmanuel Etu

Wayne State University Theses

Currently, organizations have adopted and implemented a variety of innovative quality management philosophies, approaches, and techniques to stay competitive in an ever-changing global economy. Benchmarking is one of such techniques deployed by organizations to stay competitive. The motivation for this research stems from a real-world problem being faced by hospitals in the healthcare industry who have amassed a ton of data and want to embark on benchmarking project to assess the performance of the emergency departments due to challenges faced with poor management of operations which has led to high patient boarding rates, high patient wait-times, poor quality service, low …

Uncertainty In Combustion Reaction Rates And Its Effects On Combustion Simulations, Joshua Piehl

Wayne State University Theses

This work investigates the uncertainties in reaction rates of an n-dodecane model on turbulent spray combustion simulations. Six major reactions were found to significantly impact the ignition delay of the mechanism in a 0-D batch reactor model. These reactions’ rates were independently modified and placed into individual mechanisms. These newly developed mechanisms were simulated in a 3-D turbulent spray simulation and a 0-D batch reactor at a pressure of 60 bar and temperatures from 900 to 1100 K. The combustion characteristics (e.g. ignition delays, flame lift-off length, liquid and vapor penetration) of the modified mechanisms were compared to those produced …

Developing And Validating A New Product For Gripping And Pulling Cable, Tyler Miller

Graduate Theses - Engineering Management

During on-site visits, it was discovered that the process of setting up cable for installation in conduit takes approximately 15 man-minutes of labor, costing contractors approximately $300 a day in labor costs. This integrated project examined the validity of a new product which would save labor costs by decreasing the preparation time for installing cable in conduit.

Marketing strategies were examined as well as business models. The design of the product consisted of 3D modeling, rapidly-manufactured prototypes, design space selection, testing, and refinement.

In time trials, the final product cut preparation time from 15 minutes to 1 minute, saving contractors …

The Transport Of Non-Spherical Particles In A Simulated Ocean Environment, Hannah Reed

REU Final Reports

Plastic particles contaminating the world’s oceans and accumulating in oceanic gyres has become a ubiquitous problem and the solution involving how to clean up the debris efficiently has still not been found. One particular issue is understanding where the greatest densities of debris may be. It is known that floating trash will tend to accumulate in large circular systems of ocean water called gyres, however these areas span thousands of miles of ocean. The present study aims to understand the transport of anisotropic particles in conditions similar to an oceanic environment using experimental methods in an effort to better predict …

Water Quality Factor Prediction Using Supervised Machine Learning, Kathleen Joslyn

REU Final Reports

The objective of this research is to explore prediction accuracy of water quality factors, with techniques and algorithms in machine learning consisting of a variation of support vector machines - Support Vector Regression (SVR) and the gradient boosting algorithm Extreme Gradient Boosting (XGBoost). Both the XGBoost and SVR algorithms were used to predict nine different factors with success rates ranging from 79% to 99%. Parameters of these algorithms were also explored to test the prediction accuracy levels of individual water quality factors. These parameters included normalizing the data, filling missing data points, and training and testing on a large set …

Differences In The Throughput Performance Of The Warehouse Depending On The Quality Of The Calculation Parameters, David Sourek

15th IMHRC Proceedings (Savannah, Georgia. USA – 2018)

This article explores the quality level of the parameters that are used to determine the throughput performance of the warehouse. In our model case, this is a rack warehouse where the storage and picking of goods is ensured by forklifts. All kind of goods are stored on pallets. The aim of our research is to assess to what extent the quality level (accuracy) of the description of warehouse processes influences the accuracy of the determination of the throughput performance of the warehouse. In the first part of the article, we defined the parameters and the ways in which different levels …

Hydrogen Fuel Cells, Sydney Pilgrim, Skyler Smith

ENgaging Educators in Renewable enerGY (ENERGY): Lesson Plans & Slideshows (2017-2019)

Hydrogen fuel cells are hydrogen powered energy sources. They convert chemical energy into electrical energy by separating water molecules into the two elements that make up water, Hydrogen (2) and Oxygen (1). Hydrogen fuel cells are looking to become a paramount energy producer to avoid consuming fossil fuels for power. Along with the abundance of Hydrogen in the atmosphere being a benefit of using Hydrogen powered fuel cells, the only emission from these energy sources is water vapor. Many car engines only operate at a 20% fuel efficiency, whereas fuel cell powered cars utilize 60% of the energy produced. Although …

Solar Tracking Sustainable Energy Education, Tara Hart, Donita Legonas

ENgaging Educators in Renewable enerGY (ENERGY): Lesson Plans & Slideshows (2017-2019)

Two middle school science teachers collaborated with Georgia Southern lab students to conduct research and experimentation on the benefits of utilizing a dual-axis solar tracking system to assess the amount of voltage received during various times of the day. A smaller similar dual-axis solar tracking system was designed and fabricated to utilize in the teachers’ middle school classrooms in the study of renewable energy and the engineering and design process.

Including Topographical Effects In Slant-Range Modeling, Kari C. Ward, Kyle J. Demarsy

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Spacecraft descent-to-landing navigation often includes the use of a slant-range measurement, the distance from the spacecraft to a surface along the off-nadir pointing direction of the sensor. Modeling a slant range sensor requires a reference surface, approximations of which include spherical and ellipsoidal surfaces, spherical harmonic models, and topographical maps based on prior reconnaissance data. For the spherical and ellipsoidal reference surfaces, a closed-form solution of the slant-range measurement exists. However, these approaches are inaccurate with respect to the true surface. This paper develops a method to implement digital elevation maps of a given surface to create a topography-based model …

Electric Solid Propellant Ablation In A Pulsed Electric Thruster, Matthew S. Glascock, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric solid propellants are advanced solid chemical rocket propellant that can be controlled (ignited, throttled and extinguished) with electric current. Work reported here focuses on application of electric solid propellant in a pulsed electric thruster similar to a pulsed plasma thruster. In the future it may be possible to develop a dual-mode electric solid propellant thruster that is switchable between steady applied electric current chemical mode and pulsed alternating electric current electric mode. Results presented here use a laboratory test thruster to create an arc discharge of 5-20 J per pulse in a cylindrical cavity of propellant. Results for Teflon …

Square-Root Consider Filters With Hyperbolic Householder Reflections, James S. Mccabe, Kyle J. De Mars

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Maintaining positive definiteness of a filter's error covariance estimate is of paramount importance to any stable and reliable estimation scheme. Two widely used methods for protecting a filter from loss of positive-definiteness are that of consider filtering and square-root filtering. Despite their widespread use in estimation applications, a filtering methodology that combines the two techniques has yet to be presented in a unified, streamlined architecture. This paper develops a new approach to square-root filtering using hyperbolic Householder reflections. A specialization of the method is considered to permit computationally efficient applications, and a numerical example pertaining to a ballistic reentry is …

Boundary-Layer Separation Control Using Laser-Induced Air Breakdown, Alfram Bright, Nathan Tichenor, Kevin Kremeyer, Richard Wlezien

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Modification of the flow separation characteristics of a laminar airfoil using a remotely located high-power laser was experimentally investigated in a low-speed, low-turbulence wind tunnel. A laminar airfoil model (chord length of 500 mm) was designed and fabricated to emulate the flight characteristics of a small aircraft. At 0 deg angle of attack, the airfoil model was determined to have an incipient laminar separation bubble on its lifting surface between 67 and 80% chord. A strong laser-induced breakdown was generated 2 mm upstream of the leading edge by focusing a collimated beam emitted from a 900 mW laser at 1064 …

Application Of Improved Fast Dynamic Allan Variance For The Characterization Of Mems Gyroscope On Uav, Qian Zhang, Xueyun Wang, Shiqian Wang, Chaoying Pei

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Microelectromechanical systems (MEMS) are core components in unmanned aerial vehicles (UAV). The precision of MEMS sensors is very important when the GPS signal is invalid. However, the precision and performance of MEMS sensors will be degraded by the changing of environment. Therefore, estimation and identification of the various noise terms existing in MEMS sensors are deemed to be necessary. The Allan variance is a common and standard method to analyze MEMS sensors, but it cannot be used to analyze the dynamic characteristics. The dynamic Allan variance (DAVAR) is a sliding version of the Allan variance. It is a practical tool …

Tortuosity Calculations, Blood Flow Simulations, And Mechanical Testing Of Mouse Aortae, Shawn Pavey, Jessica Wagenseil

Undergraduate Research Symposium Posters

Aortic aneurysms can lead to wall rupture or dissection, which are both deadly occurrences. The risk of developing problematic aneurysms increases with age, making them a growing concern in the USA’s aging population. Thoracic Aortic Aneurysm (TAA) treatment is highly effective if the TAA is diagnosed in time, however current surgical guidelines catch less than half of fatal TAA cases. Tortuosity (related to vessel length divided by the straight distance between two points of interest) has been proposed as a supplement to diameter based diagnosis of severity of TAA progression. This study aimed to confirm the validity of that proposal …

Effects Of Subsurface Drainage Systems On Water And Nitrogen Footprints Simulated With Rzwqm2, Kristina J. Craft, Matthew J. Helmers, Robert W. Malone, Carl H. Pederson, Linda R. Schott

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Developing drainage water management (DWM) systems in the Midwest to reduce nitrogen (N) transport to the northern Gulf of Mexico hypoxic zone requires understanding of the long-term performance of these systems. Few studies have evaluated long-term impacts of DWM, and the simulation of controlled drainage (CD) with the Root Zone Water Quality Model (RZWQM) is limited, while shallow drainage (SD) has not been examined. We tested RZWQM using nine years (2007-2015) of field data from southeast Iowa for CD, SD, conventional drainage (DD), and undrained (ND) systems and simulated the long-term (1971-2015) impacts. RZWQM accurately simulated N loss in subsurface …

A Tunable, Three-Dimensional In Vitro Culture Model Of Growth Plate Cartilage Using Alginate Hydrogel Scaffolds, Alek G. Erickson, Taylor D. Laughlin, Sarah M. Romereim, Catherine N. Sargus-Patino, Angela K. Pannier, Andrew T. Dudley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Defining the final size and geometry of engineered tissues through precise control of the scalar and vector components of tissue growth is a necessary benchmark for regenerative medicine, but it has proved to be a significant challenge for tissue engineers. The growth plate cartilage that promotes elongation of the long bones is a good model system for studying morphogenetic mechanisms because cartilage is composed of a single cell type, the chondrocyte; chondrocytes are readily maintained in culture; and growth trajectory is predominately in a single vector. In this cartilage, growth is generated via a differentiation program that is spatially and …

Coupling Of Mechanical And Electromagnetic Fields Stimulation For Bone Tissue Engineering, Alyaa I. Aldebs

Browse all Theses and Dissertations

Alternative bone regeneration strategies that do not rely on harvested tissue or exogenous growth factors and cells are badly needed. However, creating living tissue constructs that are structurally, functionally and mechanically comparable to the natural bone has been a challenge so far. A major hurdle has been recreating the bone tissue microenvironment using the appropriate combination of cells, scaffold and stimulation to direct differentiation. This project presents a bone regeneration formulation that involves the use of human adipose-derived mesenchymal stems cells (hASCs) and a 3D scaffold based on a self-assembled peptide hydrogel doped with superparamagnetic nanoparticles (NPs). Osteogenic differentiation of …

Mechanical Annealing Of Model Glasses: Effects Of Strain Amplitude And Temperature, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

Molecular dynamics simulations are performed to examine the dynamic response of amorphous solids to oscillatory shear at finite temperatures. The data were collected from a poorly annealed binary glass, which was deformed periodically in the elastic regime during several hundred shear cycles. We found that the characteristic time required to reach a steady state with a minimum potential energy is longer at higher temperatures and larger strain amplitudes. With decreasing strain amplitude, the asymptotic value of the potential energy increases but it remains lower than in quiescent samples. The transient decay of the potential energy correlates well with a gradual …

Controlled Switching Of Reactive Loads And Commisioning Regimes, Eoin Cowhey

Masters

Switching is a vital task in any power system for ensuring its safe and reliable operation. Switching may be necessary for fault clearance, to ensure wider system stability and to prevent damage to plant. It is essential for isolation, to allow technicians to carry out maintenance tasks safely. Also, switching of reactive loads such as shunt capacitor banks and shunt reactors, is crucial for controlling system voltage.

Switching of some loads however, may produce voltage transients and heavy transient inrush currents which can impact on wider system power quality, impact customers and cause damage or deterioration of the insulation of …

Design And Implementation Of A Micro-Inverter For Photovoltaic Applications, Chi-Thang Phan-Tan

Masters

The objective of this work is to design and build a novel topology of a micro-inverter to directly convert DC power from a photovoltaic module to AC power. In the proposed micro-inverter, a structure with two power stages, which are DC/DC and then DC/AC converters, is used. A novel MPPT algorithm is implemented and evaluated in the DC/DC converter to optimize the solar panel energy production. The new method operates with an efficiency of 97.9%, which is a 1% improvement on the standard method, and a response time of

In this research, the following approach is taken. A literature review …

Rheology, Morphology And Electronic Properties Of Hybrid Copper Organic Decompose Conductive Ink, Chaiwat Klaewwigkij

Chulalongkorn University Theses and Dissertations (Chula ETD)

Hybrid Metal-Organic Decomposition (HMOD) inks containing alkanol amines copper complex solution with fine copper particles show high potential for flexible printed electronics application. Conductive patterns are fabricated from HMOD inks by screen printing onto a polyimide substrate. This work studies the effects of co-solvent, copper particles loading, and viscosity of the inks on properties of the conductive patterns obtained. Firstly, the effects of co-solvent related to the stability of the HMOD inks and the impact of preparation time related to the crack of the conductive pattern are examined. The HMOD inks are prepared from copper formate (CuF), and alkanol amines …

การปรับปรุงประสิทธิภาพการทำงานของโรงไฟฟ้าพลังงานแสงอาทิตย์โดยใช้การบำรุงรักษาเชิงรุก, มธุรส มิ่งมงคล

Chulalongkorn University Theses and Dissertations (Chula ETD)

แม้ว่ามีดำเนินงานการบำรุงรักษาเชิงป้องกันในโรงไฟฟ้าพลังงานแสงอาทิตย์แต่ยังคงมีการขัดข้องของเครื่องจักรต่างๆ โรงงานไฟฟ้าพลังงานแสงอาทิตย์ที่เป็นกรณีศึกษานี้ได้กำหนดค่าเป้าหมายความพร้อมของเครื่องจักรไว้สูงกว่า 99.25% เมื่อเวลาผ่านไปพบว่าค่าความพร้อมใช้งานมีแนวโน้มต่ำลง แม้ว่าก่อนการปรับปรุงมีค่าความพร้อมใช้งานเฉลี่ย 99.43% ส่วนเบี่ยงเบนมาตรฐานมีค่าสูงถึง 1.20% แสดงให้เห็นว่า การบำรุงรักษาเชิงป้องกันที่มีอยู่นั้นอาจไม่เพียงพอที่จะจัดการปัญหานี้ได้ งานวิจัยนี้จึงได้นำการบำรุงรักษาเชิงรุกมาเป็นกลยุทธ์ในการปรับปรุงค่าความพร้อมการใช้งานของเครื่องจักร มีการวิเคราะห์ผลกระทบของความเสียหาย โอกาสเกิดและความรุนแรง และมีการหาสาเหตุที่ทำให้เครื่องจักรเสีย หลังจากนั้นได้ทำการปรับปรุงแผนการบำรุงรักษาเชิงป้องกันและสร้างแผนการบำรุงรักษาเชิงพยากรณ์ หลังจากที่ดำเนินการตามแผนงานพบว่าสามารถทำให้ค่าความพร้อมใช้งานเพิ่มขึ้นเฉลี่ยเป็น 99.69% ส่วนเบี่ยงเบนมาตรฐานเป็น 0.41% เวลาเฉลี่ยในการขัดข้องของเครื่องจักรลดลง 63.90% จำนวนครั้งที่เกิดการขัดข้องลดลง 40.28% และกำลังการผลิตที่สูญเสียลดลงได้ 28.44%

การวิเคราะห์วอเตอร์ฟุตพรินต์ในกระบวนการผลิตเบนซีนและพาราไซลีน, เรืองรัตน์ เรืองเดช

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยฉบับนี้เป็นการวิเคราะห์ผลกระทบจากการใช้น้ำ ของกระบวนการผลิตเบนซีนและพาราไซลีน ทั้งการใช้น้ำทางตรงและทางอ้อม การใช้น้ำทางตรงประกอบไปด้วยการใช้น้ำในกระบวนการผลิตซึ่งสามารถวัดได้โดยตรงจากข้อมูลของโรงงาน และการใช้น้ำทางอ้อมประกอบไปด้วยการใช้น้ำในส่วนของการได้มาซึ่งวัตถุดิบ การใช้ไฟฟ้า การผลิตไอน้ำ การผลิตไนโตรเจน รวมถึงการใช้น้ำในกระบวนการขนส่ง ซึ่งโรงงานไม่สามารถวัดโดยตรงได้ต้องมีการเก็บข้อมูลจากแหล่งอ้างอิงอื่นๆที่เชื่อถือได้ วิธีการประเมินผลกระทบการใช้น้ำที่ใช้ในงานวิจัยฉบับนี้ใช้วิธีวอเตอร์ฟุตพรินต์ซึ่งเป็นวิธีที่ทำให้ทราบผลกระทบจากการใช้น้ำที่แท้จริงตลอดวัฏจักรชีวิตของผลิตภัณฑ์ โดยอ้างอิงวิธีการประเมินตามข้อกำหนดและแนวทางของ ISO 14046 ผลลัพธ์จากการประเมินพบว่าผลิตภัณฑ์เบนซีนและพาราไซลีน มีค่าวอเตอร์ฟุตพรินต์ซึ่งวัดผลกระทบในแง่ของการขาดแคลนน้ำ(Water Scarcity Footprint,WSF) ต่อ 1 กิโลกรัมเท่ากับ 0.613 LiterH2Oeq และ 1.432 LiterH2Oeq ตามลำดับ โดยทั้งเบนซีนและพาราไซลีนมีค่า WSF สูงสุดจากการใช้น้ำทางอ้อม ซึ่งมีค่าสูงในการใช้ไฟฟ้าและการได้มาซึ่งคอนเดนเสท และรองลงมาคือ WSF จากการใช้น้ำทางตรงซึ่งมีค่า WSF สูงในส่วนของการระเหยของน้ำในระบบหล่อเย็น แต่เนื่องการลดผลกระทบจากการใช้น้ำจะมีความเป็นไปได้ในการลดจากใช้น้ำทางตรงมากกว่าทางอ้อม เพราะสามารถควบคุมได้โดยตรงจากโรงงานถึงแม้ว่าอาจจะทำให้ผลกระทบลดลงได้ไม่มากก็ตาม จึงเสนอการนำมาตรการในการลดการใช้น้ำทางตรงร่วมด้วย โดยแบ่งมาตรการเป็น 2 ส่วนคือการลดผลกระทบที่เกิดจากการใช้น้ำทางตรง และการลดผลกระทบจากการใช้น้ำทางอ้อม เพื่อให้กระบวนการผลิตเบนซีนและพาราไซลีนเกิดการใช้น้ำอย่างมีประสิทธิภาพสูงสุด

Developing An Automated System For Supporting Strut Arrangement In Deep Excavation, Pisal Nov

Chulalongkorn University Theses and Dissertations (Chula ETD)

In strut arrangement, current software could detect the constructible problems like clashes. However, this software had some limitations including (1) unable to visualize all clash occurrences on each strut, (2) unable to distinguish between occurrence and non-occurrence of the clash, and (3) unable to check tolerance and spacing problems. Thus, the strut arrangement was still an inefficient process. The research objective was to develop an automated system for supporting strut arrangement in deep excavation. In the methodology, an in-depth interview was conducted to collect the information and knowledge of strut arrangement and analyzed with transcription analysis. This information and knowledge …