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Full-Text Articles in Engineering
Enhancing Stability Of High-Nickel Cathodes For Lithium-Ion Batteries Through Additive Manufacturing Of Cathode Structure, Matthew Sullivan
Enhancing Stability Of High-Nickel Cathodes For Lithium-Ion Batteries Through Additive Manufacturing Of Cathode Structure, Matthew Sullivan
Mechanical Engineering Undergraduate Honors Theses
Lithium-ion batteries (LIBs) are currently the best method to store electrical energy for use in portable electronics and electronic vehicles. New cathode materials for LIBs are consistently studied and researched, but few are as promising and attainable as nickel-rich transition metal oxides such as LiNi1-x-yMnxCoyO2 (NMC). NMC materials exist with many different mass ratios, but higher nickel content materials provide higher energy density. With this increase in capacity comes a sacrifice with cyclability, as high-nickel NMC variants are prone to structure collapse, transition metal dissolution, and cracks due to volume change. In this report, mechanical modification of the electrode by …
Nanoscratch Study Of Diamond-Like Carbon Coatings With A Polydopamine + Sio2 Adhesive Underlayer, Anna Fisher
Nanoscratch Study Of Diamond-Like Carbon Coatings With A Polydopamine + Sio2 Adhesive Underlayer, Anna Fisher
Mechanical Engineering Undergraduate Honors Theses
Diamond-like carbon (DLC) coatings have a wide array of desirable characteristics such as low friction, high hardness, and scratch resistance. Due to high residual stress and thermal mismatch, DLC films experience adhesion difficulties when bonded with metallic substrates, leading to cracking and delamination. In this study, the properties of a new coating with a polydopamine underlayer and silica nanoparticles bonded to a stainless-steel substrate (PDA+SiO2/DLC) were studied alongside three other samples, one with a polydopamine underlayer (PDA/DLC), one with a trimethylsilane (TMS) underlayer (TMS/DLC), and one with no underlayer (DLC only). Nanoscratch tests were performed with a 1 μm spheroconical …
A History And Status Of Wind Energy Potential In Arkansas, Pre And Post Covid-19, Will Blasingame
A History And Status Of Wind Energy Potential In Arkansas, Pre And Post Covid-19, Will Blasingame
Mechanical Engineering Undergraduate Honors Theses
Historically, wind-generated electricity has been the largest renewable energy sources in the United States. Wind-rich regions like Oklahoma and Texas have fueled growth and sold that electricity to electric utilities located in wind-poor states like Arkansas in the form of Power Purchase Agreements. Future technologies such as Vertical Axis Wind Turbines, small wind turbines, and Tesla turbines designed to generate electricity from wind show promise in unlocking more expensive wind resources in regions like Northwest Arkansas by mitigating concerns about low wind speeds and noise. However, more factors than just feasibility influence the growth of wind power. Governmental policies such …
Challenges And Opportunities Of Layered Cathodes Of Linixmnyco(1-X-Y)O2 For High-Performance Lithium-Ion Batteries, Jason Frank
Challenges And Opportunities Of Layered Cathodes Of Linixmnyco(1-X-Y)O2 For High-Performance Lithium-Ion Batteries, Jason Frank
Mechanical Engineering Undergraduate Honors Theses
High energy density lithium-ion batteries (LIBs) are widely demanded for portable electronic devices and electrical vehicles. Layered-structure LiCoO2 oxide (LCO) has been the most commonly used cathode material in commercial LIBs. Compared to LCO, LiNi1-x-yMnxCoyO2 (NMC) cathodes are particularly attractive due to their reduced cost and higher capacity. Among the NMC cathodes, nickel-containing LiNi0.5Co0.3Mn0.2O2 (NMC532) is one of the most promising cathode materials undergoing intensive investigation, but suffers from a series of technical issues, such as structural instability, performance fading, and safety issues. In this …
Bgaas Alloy Semiconductors For Lasers On Silicon, Joshua Mcarthur
Bgaas Alloy Semiconductors For Lasers On Silicon, Joshua Mcarthur
Mechanical Engineering Undergraduate Honors Theses
In the world of semiconductors today, there is a large dissonance between optical devices and electrical application. Due to the limitations of electron transport, photonic integrated circuits are soon-to-be vital in fields like telecommunications and sensing. Right now, these PIC’s are mostly made from indium phosphide. Due to its ubiquitous nature, however, there is a huge push to integrate efficient optics with silicon. It’s cheap, abundant, dope-able, and our electronic infrastructure is based on it. The reason why silicon photonics aren’t already commercialized is because of silicon’s indirect bandgap—it is inefficient with optical applications. The problem with combining direct gap …
Design Of Wind Turbine Tower Height And Blade Length: An Optimization Approach, Ryan Wass
Design Of Wind Turbine Tower Height And Blade Length: An Optimization Approach, Ryan Wass
Mechanical Engineering Undergraduate Honors Theses
The wind industry is a fast growing market and is quickly becoming competitive with traditional non-renewable energy resources. As with any developing industry, research must continually be redefined as more complex understandings of design variables are learned. Optimization studies are common ways to quickly refine design variable selections. Historical wind turbine data shows that the tower hub height to rotor diameter ratio scales almost linearly. However there is no specific rule that dictates the optimum hub height for a given diameter. This study addresses this question by using an Excel based optimization program to determine the height to diameter ratio …
Non-Covalent Functionalization Of Graphene Films For Uniform Nanoparticle Deposition Via Atoic Layer Deposition, Ty Seiwert
Mechanical Engineering Undergraduate Honors Theses
Graphene functionalized with platinum (Pt) and palladium (Pd) has proven to be highly effective as a hydrogen sensor. Deposition methods such as Atomic layer deposition (ALD) can be further enhanced by pretreating the graphene with a non-covalent surfactant prior to nanoparticle deposition. In this study, graphene-based sensing devices will be fabricated by ALD deposition. The graphene will be non-covalently functionalized using sodium dodecyl sulfate (SDS) anionic surfactant prior to ALD deposition. The aim of this study is to test the deposition pattern achieved by varying the amount of time that graphene is treated with the SDS surfactant. Initially, ALD deposition …
System-Layout-Dependent Thermally Induced Solder Stress & Reliability Implications, Ange C. Iradukunda
System-Layout-Dependent Thermally Induced Solder Stress & Reliability Implications, Ange C. Iradukunda
Mechanical Engineering Undergraduate Honors Theses
Electronic flip chip assemblies consist of dissimilar component materials, which exhibit different CTE. Under thermal cyclic operating conditions, this CTE mismatch produces interfacial and interconnect stresses, which are highly dependent on system layout. In this paper, sensitivity analyses are performed using ANSYS FEA to establish how the proximity and arrangement of neighboring devices affect interconnect stress. Flip chip alignment modes ranging from edge-to-edge to corner-to-corner are studied. Results of these FEA studies, demonstrated that closely packing devices together has the effect of making them act as one. This results in a significant increase in the thermomechanical stresses induced on peripheral …
Industrial Energy Consumption, Benchmarking, And Analysis In The United States, Daniel Maldonado
Industrial Energy Consumption, Benchmarking, And Analysis In The United States, Daniel Maldonado
Mechanical Engineering Undergraduate Honors Theses
The purpose of this paper is to analyze the energy consumption of the industrial sector in the United States, and to identify the tools that can be used to minimize the consumption and improve the energy efficiency of all facilities in the country. The first part of the paper is a historical analysis of the industrial sector energy consumption, where the different energy sources are identified. The second part details different electronic tools that will provide facilities the ability of performing benchmarking, in order to understand their energy performance. Finally, the third part of this paper provides information about the …
A Look At Commercial Building Energy Use And Energy Efficiency Technologies From 1980 To Present, Marvin M. Arroyo
A Look At Commercial Building Energy Use And Energy Efficiency Technologies From 1980 To Present, Marvin M. Arroyo
Mechanical Engineering Undergraduate Honors Theses
Energy consumption has increased considerably in the last fifty years as population rises. At the same time, design and efficiency of all equipment used in commercial buildings have changed as well. The purpose of this thesis is to explain how HVAC systems have changed and how they have affected energy consumption. Entities like the US Department of Energy (DOE) and the US Energy Information Administration (EIA) facilitate the data-gathering process by offering databases of energy information from actual monthly energy bills to promote public understanding of energy and its interaction with the economy and the environment. Moreover, in order to …
Benefits Of Leed Designs In Arkansas K-12 Schools, Philip Thrift
Benefits Of Leed Designs In Arkansas K-12 Schools, Philip Thrift
Mechanical Engineering Undergraduate Honors Theses
This paper provides and evaluation of an existing LEED certified sustainable green building for energy-efficiency, environmental impact, economic value, and occupant health. The new Bethel Middle School located in Bryant, Arkansas was the first LEED (Leadership in Energy and Environmental Design) certified public school building in the state. Based on actual building specifications and validated with the first year's utility bills, a simulation model was used to evaluate various design aspects of the school building. The building's baseline energy usage was compared with numerous energy and environmental scenarios. Results include both environmental and economic assessments. Overall, the study found that …