Digital Commons Network^™

Fabrication Of Binder-Free Electrodes Based On Graphene Oxide With Cnt For Decrease Of Resistance, Di Zhang

Masters Theses

In electrode double layer capacitor (EDLC), electrodes usually contain binder materials to provide adhesion between electrode materials. However, binder materials usually bring unwanted resistances to the component due to their non-conductivity properties and the occupation of ion cavities. The purpose of this thesis is to demonstrate the feasibility of fabricating electrodes for EDLCs by using carbon nanotubes (CNTs) and graphene oxide (GO) without using any binding materials. At the same time, investigating the binder-free electrode’s electrochemical properties and make an assumption of its potential application in the future.

The slurry of binder-free electrodes was fabricated by ultrasonicating water suspended CNTs …

Nozzle Clogging Prevention And Analysis In Cold Spray, Alden Foelsche

Masters Theses

Cold spray is an additive manufacturing method in which powder particles are accelerated through a supersonic nozzle and impinged upon a nearby substrate, provided they reach their so-called critical velocity. True to its name, the cold spray process employs lower particle temperatures than other thermal spray processes while the particle velocities are comparably high. Because bonding occurs mostly in the solid state and at high speeds, cold spray deposits are distinguished for having low porosity and low residual stresses which nearly match those of the bulk material.

One complication with the cold spray process is the tendency for nozzles to …

A Study On Latent Thermal Energy Storage (Ltes) Using Phase Change Materials (Pcms) 2020, Ritvij Dixit

Masters Theses

The significant increase in energy requirements across the world, provides several opportunities for innovative methods to be developed to facilitate the storage and utilization of energy. The major energy demand is in the form of electrical energy for domestic as well as industrial sectors, a large part of which are the heating and cooling requirements. Appropriate utilization of thermal energy storage can effectively aid in reducing the electrical demand by storage and release of this thermal energy during peak hours.

Thermal Energy Storage using Phase Change Materials (PCMs) is an attractive method of energy storage, with a wide variety of …

Synthesis And Characterization Of Non-Pgm Catalysts For Fuel Cell Applications, Sudharsan Sridhar

Masters Theses

Fuel Cells convert the chemical energy of a fuel and an oxidizing agent into electricity through a pair of redox reactions. Proton Exchange Membrane (PEM) fuel cells convert (efficiency-60%) hydrogen and air to power the electric motors with zero emissions, facilitating the development of environmentally friendly and sustainable automobile technologies. One of the major obstacles for larger commercial viability of Fuel Cells for automobile applications is their cost-effectiveness. Currently, fuel cells use platinum as a catalyst material, which is prohibitively expensive for commercial automobile applications. The development of non-Platinum Group Metal (non-PGM) catalyst materials with similar electrochemical performance to that …

Development Of A Tiny House Design Tool To Increase Safety, Efficiency, And Cost-Effectiveness, Michael Joseph Stratton Ii

Masters Theses

A growing number of people are choosing to live more sustainably, and this is commonly done through living in an extremely small house, also called a “tiny house”. There is no set definition for a tiny house, but it typically refers to a structure less than 500 ft2, sometimes built by the homeowner, and frequently built on a travel trailer.

The popularity of tiny houses has increased over the years due to different television shows, internet videos, and photo sharing websites, but the technical details are rarely covered, which is why this study examines the structural, stability, weight, and thermal …

Investigating Localized Performance And Mass Transport Phenomena In Polymer Electrolyte Water Electrolyzers, Frida Helena Roenning

Masters Theses

In the face of increasing demand for renewable energy sources to replace fossil fuels, current technologies face the issue of steady energy supply from source to power distribution. As most current renewable energy methods either rely on intermittent natural sources or are geographically bound, they require an energy storage medium. Polymer Electrolyte Water Electrolyzers are a theoretically ideal solution to this demand, but they require some performance improvements in practice to be economically viable. This study analyses the current distribution in such electrolyzers in the aim of gaining insight to improve their performance. The current distribution diagnostic can capture local …

Design And Integrity Testing Of Sapphire Optical Windows In A Cryogenic Pressure System, Matthew David Williamson

Masters Theses

The performance of cryogenic liquid hydrogen neutron moderators at the Spallation Neutron Source (SNS) is significantly impacted by the ratio of orthohydrogen and parahydrogen present in the moderator vessels. High parahydrogen (>99%) content is desirable for peak brightness and consistent neutronic performance. Liquid hydrogen will naturally stabilize to a high parahydrogen ratio, but the conversion requires 3-7 days to complete (the “satisfactory” parahydrogen level varies between various beamline instruments). Ortho-to-parahydrogen convertor modules will be installed in the Cryogenic Moderator System (CMS) process loops as part of the Proton Power Upgrade Project (PPUP) at SNS. These catalysts will drive a …

Measurement And Analysis Of Pressure Profile For Nozzle Based Single Screw Extrusion Systems, Jake Dvorak

Masters Theses

Most large-scale material-extrusion (MatEx) AM systems utilize a single screw extruder. Simulating flow rate and operating pressures of extrusion systems is notoriously difficult without resorting to full finite element analysis due to the phase change and non-Newtonian nature of relevant polymers. This study characterized two machines of interest: a Big Area Additive Manufacturing (BAAM) system and a Randcastle Microtruder. A custom nozzle adapter was fabricated to gather pressure data within the nozzle and mimic the die design of the BAAM on the Microtruder system. Several theories were tested for overall machine output and max pressure. Feed and compression zone theories …

Short Term Energy Forecasting For A Microgird Load Using Lstm Rnn, Akhil Soman

Masters Theses

Decentralization of the electric grid can increase resiliency (during natural disasters) and can reduce T&D energy losses and emissions. Microgrids and DERs can enable this to happen. It is important to optimally control microgrids and DERs to extract the greatest economic, environmental and resiliency benefits. This is enabled by robust forecasting to optimally control loads and energy sources. An integral part of microgrid control is power side and load side demand forecasting.

In this thesis, we look at the ability of a powerful neural network algorithm to forecast the load side demand for a microgrid using the UMass campus as …

Optimization Of Thermal Energy Storage Sizing Using Thermodynamic Analysis, Andrew Villanueva

Masters Theses

The aim of this thesis is to examine the effect that Thermal Energy Storage (TES) sizing has on a building’s ability to meet heating and cooling demands in an energy and cost efficient manner. The focus of the research is the quantification the effects of TES for system sizing and boiler cycling. Research is accomplished by modelling TES systems with various storage capacities using thermodynamic analysis. Energy costs are subject to increase during peak usage periods due to a limited supply of energy. Peak heating and cooling periods also force thermal systems to be sized for loads that are only …

Survivability Investigation Of Cylindrical Shaped Water Cooled Probe In High Heat Flux Conditions, Joshua Osborne

Masters Theses

Diagnostics and data collection downstream of turbine engine augmentors and scramjet combustors provide critical information for turbine engine and scramjet engine developers. One important diagnostic tool is the use of imaging measurement instruments, which are primarily used by the aeropropulsion ground testing community to assess flame holder stability and uniformity in turbine engines. The survivability limitations of these imaging probes are important to understand for use in applications behind ramjet or scramjet engines, where mass flows and exhaust temperatures exceed typical engine augmentor exhaust streams. At a minimum, imaging data acquired behind ramjet and scramjet engines would be used to …

Modeling Of Electrical Grid Systems To Evaluate Sustainable Electricity Generation In Pakistan, Muhammad Mustafa Amjad

Masters Theses

Pakistan has always had a history of severe energy shortfalls, which rose up to an alarming 33% in 2013. This situation was countered by investments in the energy sector through the China Pakistan Economic Corridor (CPEC), which were unfortunately largely based on brown fuels. Although beneficial in the short term, these investments do not bode well for the climate scenario of Pakistan, with various parts of the country already having experienced temperatures rise of 1-3°C. To ensure that the current situation doesn’t exacerbate and is tackled in a timely manner, this research aims to examine how the untapped potential of …

Sundown: Model-Driven Per-Panel Solar Anomaly Detection For Residential Arrays, Menghong Feng

Masters Theses

There has been significant growth in both utility-scale and residential-scale solar installa- tions in recent years, driven by rapid technology improvements and falling prices. Unlike utility-scale solar farms that are professionally managed and maintained, smaller residential- scale installations often lack sensing and instrumentation for performance monitoring and fault detection. As a result, faults may go undetected for long periods of time, resulting in generation and revenue losses for the homeowner. In this thesis, we present SunDown, a sensorless approach designed to detect per-panel faults in residential solar arrays. SunDown does not require any new sensors for its fault detection and …

Development Of A Finite Element Model Of The Stamping Process To Predict The Natural Frequencies Of Dimpled Beams, Varad Vasudeo Pendse

Masters Theses

Creating dimples on beams has been proven to be an effective way of altering their vibrational behavior. The objective of this research is to simulate the process of stamping using the finite element (FE) method to create a model of a dimpled beam. This dimple has non-uniform thickness, so it shows close agreement with its real-life counterpart.

ANSYS® Parametric Design Language (APDL) is used to build a three-dimensional (3-D) finite element model and simulate the process of stamping used to create the dimple. The structural simulation is validated by calculating the thickness and width of the deformed geometry of the …

Comparison Of Optimal Energy Management Strategies Using Dynamic Programming, Model Predictive Control, And Constant Velocity Prediction, Amol Arvind Patil

Masters Theses

Due to the recent advancements in autonomous vehicle technology, future vehicle velocity predictions are becoming more robust which allows fuel economy (FE) improvements in hybrid electric vehicles through optimal energy management strategies (EMS). A real-world highway drive cycle (DC) and a controls-oriented 2017 Toyota Prius Prime model are used to study potential FE improvements. We proposed three important metrics for comparison: (1) perfect full drive cycle prediction using dynamic programming, (2) 10-second prediction horizon model predictive control (MPC), and (3) 10-second constant velocity prediction. These different velocity predictions are put into an optimal EMS derivation algorithm to derive optimal engine …

Fatigue Damage Characterization By Surface Roughness And Instrumented Micro – Hardness Measurements, Suraj Sanjay Nikam

Masters Theses

Fatigue is an essential consideration in the design of high performance, safety-critical structures, and components, as fatigue failure constitutes more than 70% of failures in dynamically loaded components. This research aims to shed light on the effect of surface roughness on the micro-hardness in metals through experimental techniques (Part 1), the correlation between the traditional fatigue testing and instrumented cyclic micro-hardness testing to determine the material properties modeled by Ramberg - Osgood relationship(Part 2), and the effect of the fatigue damage on micro-hardness and surface roughness (Part 3).

For this research, Al 7075 - T651 and Al 6061 - T651 …

On The Investigation Of Hot Tearing Behavior Of Continuous Cast Steel, Yanru Lu

Masters Theses

”Hot tearing has long been recognized as a major problem that plagues the development of the continuous casting process and results in low-quality products. Understanding of the mechanisms and the required conditions for the hot tearing formation is important for industries but has not been well-established yet. Thus, this research focuses on the hot tearing issue observed in continuous cast steel, by providing a summary of the current research progress and then introducing a new laboratory method to determine the thermo-mechanical properties relevant to hot tearing of different steel grades under different solidification conditions. In this method, an apparatus was …

Performance Evaluation Of Alsi10mg Fabricated By A Selective Laser Melting Process, David Michael Murphy

Masters Theses

“Selective laser melting is becoming a widely used additive manufacturing technique that melts metal powder in a layer by layer process in order to build a desired part or geometry. Like many additive processes, selective laser melting allows for fabrication of parts with complex geometries. In order to fabricate a fully dense part there are a number of variables to take into account including: powder characteristics, laser parameters, and environmental parameters. Each of these variables can affect the microstructure and thus the mechanical performance of an additively manufactured part. In this work, the aluminum alloy AlSi10Mg was investigated. AlSi10Mg is …

Modal Analysis As Non-Destructive Testing Technique For Additively Manufactured 304l Stainless Steel Parts, Tristan N. Cullom

Masters Theses

“Non-Destructive Testing (NDT) methods for Additively Manufactured (AM) parts is an ongoing field of research in the additive community due to its ability to determine if a part can be deemed viable for field usage. This study presents modal analysis as a NDT method for AM parts. For production builds that have multiple copies of the same part, a correcting technique can be used such that the frequencies of the parts under test can be reliably compared against each other, which saves both time and money compared to other traditional NDT methods. This study was able to develop a novel …

Influence Of Input Energy On Mechanical Properties Of Laser Powder Bed Fused Aisi 304l Stainless Steel, Tan Pan

Masters Theses

“Powder Bed Fusion process with selective laser melting technique is popularly adopted in additive manufacturing area on account of its layer by layer manufacturing fashion capable of fabricating components with complex internal and external geometries and structures. However, the process-property map is unique and vital for different materials and AM configurations used for fabrication. The process parameter is identified as a significant factor that heavily influences the properties and performances of the printed materials.

Current work aimed to extend the existing knowledge on Laser Powder Bed Fusion fabricated AISI 304L by accessing the influence of varying energy input on the …

Mid-Infrared Chiral Metsurface Coupling With Molecular Vibration, Md Shamim Mahmud

Masters Theses

“The mid-infrared design of chiral metamaterial shows a tremendous absorption capability of infrared rays, and it has the significant application of circular dichroism based device development. Plasmon-phonon coupling is one of the application of metamaterial that provides a new path for tailoring the surface in the nanoscale, which is also applicable in molecules detection. It is possible to change the Plasmon-Phonon coupling strength not only through the chemical change of molecules but also by changing the metamaterial light-matter interaction property. So far, linearly polarized light shows the strong coupling between metamaterial and molecules. However, it is possible to observe strong …

In-Situ X-Ray Imaging Of The Selective Laser Melting Process, Meelap M. Coday

Masters Theses

"Fusion-based metal additive manufacturing (AM) has garnered much interest in recent decades. Despite the popularity of fusion-based AM technologies such as selective laser melting (SLM), there are still fundamental questions and uncertainties that need to be addressed. In this work, we focus on the understanding of the undercooling in the SLM process and the uncertainties induced by the laser beam size, power, and scan speed. First, we report the estimation of undercooling in the SLM process from the solidification rate measured by in-situ high-speed synchrotron x-ray imaging, based on the dendrite growth velocity model. The undercooling changes as a function …

Combining Laser Aided Ablation And Polishing To Minimize Surface Roughness Of Additively Manufactured Aluminium Components, Sahil Bipinkumar Patel

Masters Theses

“The surface roughness of additively manufactured parts is much higher than the acceptable range for most applications, thus post-processing is needed to qualify these parts for use. Laser polishing can be used to bring the surface roughness in an admissible range, but if the initial roughness is very high then the energy density for the polishing process needs to be very high to achieve a significant reduction in roughness. This high energy density can produce many process defects. Also, laser polishing alone cannot get rid of high wavelength asperities. Any waviness in the part can be linked with initial waviness …