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Articles 61 - 90 of 8194

Full-Text Articles in Engineering

Interpersonal Skills In A Sociotechnical System: A Training Gap In Flight Decks, Kimberly Perkins Atp, Fraes, Sourojit Ghosh, Crystal Hall Phd Jan 2024

Interpersonal Skills In A Sociotechnical System: A Training Gap In Flight Decks, Kimberly Perkins Atp, Fraes, Sourojit Ghosh, Crystal Hall Phd

Journal of Aviation/Aerospace Education & Research

This research analyzed the perceptions of interpersonal skills on established aviation safety models, Crew Resource Management (CRM), and Threat and Error Management (TEM) using feedback from industry pilots. The flight deck is a sociotechnical system where much research has focused on the technical aspect, whereas we spotlight its socio aspect. The aviation industry must invest in training pilots on interpersonal skills to enhance safety through increased efficacy of safety models integrated throughout existing training programs. A 34-question survey was disseminated across both commercial and business aviation pilots (N=822). We explored three research questions regarding pilots’ perceived training on interpersonal skills …


Evaluating The Effectiveness Of Game-Based Virtual Reality In Satellite Ground Control Operations Education And Training, Lana Laskey, Joseph R. Keebler, Paul M. Cairns, Geovanny Lopez Jan 2024

Evaluating The Effectiveness Of Game-Based Virtual Reality In Satellite Ground Control Operations Education And Training, Lana Laskey, Joseph R. Keebler, Paul M. Cairns, Geovanny Lopez

International Journal of Aviation, Aeronautics, and Aerospace

There is increased global demand for satellite amenities such as navigation, communications, weather reporting, disaster management, agricultural operations, or humanitarian assistance. The growing demand for satellite technology amplifies the need for highly trained satellite operators. Traditional simulation training methods typically utilize two-dimensional computer displays. However, training approaches involving game-based instruction and immersive virtual reality have shown benefits when integrated with complex disciplines and may provide an advanced training alternative for satellite operators. Game-based instruction enhances user motivation and cognitive engagement, while immersive virtual reality promotes user presence and prolonged cognitive engagement. The combination of these two training methods, noted as …


Integrated Organizational Machine Learning For Aviation Flight Data, Michael J. Pritchard Ph.D., Austin T. Walden Ph.D., Paul J. Thomas Ph.D. Jan 2024

Integrated Organizational Machine Learning For Aviation Flight Data, Michael J. Pritchard Ph.D., Austin T. Walden Ph.D., Paul J. Thomas Ph.D.

Journal of Aviation/Aerospace Education & Research

Increased availability of data and computing power has allowed organizations to apply machine learning techniques to various fleet monitoring activities. Additionally, our ability to acquire aircraft data has increased due to the miniaturization of small form factor computing machines. Aircraft data collection processes contain many data features in the form of multivariate time series (continuous, discrete, categorical, etc.) which can be used to train machine learning models. Yet, three major challenges still face many flight organizations: 1) integration and automation of data collection frameworks, 2) data cleanup and preparation, and 3) developing an embedded machine learning framework. Data cleanup and …


Oxidation Of Additively Manufactured Zrb2–Sic In Air And In Co2 At 700–1000 °C, Marharyta Lakusta, Nicholas M. Timme, Abid H. Rafi, Jeremy Lee Watts, M. (Ming) C. (Chuan) Leu, Gregory E. Hilmas, William G. Fahrenholtz, David W. Lipke Jan 2024

Oxidation Of Additively Manufactured Zrb2–Sic In Air And In Co2 At 700–1000 °C, Marharyta Lakusta, Nicholas M. Timme, Abid H. Rafi, Jeremy Lee Watts, M. (Ming) C. (Chuan) Leu, Gregory E. Hilmas, William G. Fahrenholtz, David W. Lipke

Materials Science and Engineering Faculty Research & Creative Works

Oxidation behavior of additively manufactured zrb2–sic in air and in co2 is reported in the temperature range of 700–1000 °c. Observed scale morphologies in air and in co2 were similar, featuring an outer borosilicate layer and an inner porous zirconia layer containing partially oxidized silicon carbide particles and remnant borosilicate products. Oxide scale thicknesses and parabolic scaling constants in air were approximately twice those observed in co2 across all studied temperatures. Activation energies for oxidation of 140 ± 20 kj/mol in air and 110 ± 20 kj/mol in co2 were determined, indicating similar diffusion processes that appear to be rate-limiting. …


Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng Dec 2023

Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng

Dissertations

This dissertation introduces a novel vacuum technology that leverages low-pressure saturated steam and cooling-controlled condensation, offering an efficient way to utilize low-grade thermal energy sources like waste heat, steam, or solar energy. At the heart of this technology is a unique duo-chamber vacuum pump system, featuring a reciprocating piston and a heat-conductive wall, designed to generate a vacuum through steam-condensation and cooling processes.

The core of this research lies in developing and validating mechanistic models for the steam-condensation depressurization process, a complex phenomenon involving phase change and transport mechanisms. Prior to this work, these mechanisms were not sufficiently modeled or …


Indicators Affecting Passenger Service Processes And Their Scientific Interpretation, Maxliyoxon Madaminova Maxamatjon Qizi, Saidazim Amanullayevich Ganihodjayev Dec 2023

Indicators Affecting Passenger Service Processes And Their Scientific Interpretation, Maxliyoxon Madaminova Maxamatjon Qizi, Saidazim Amanullayevich Ganihodjayev

Technical science and innovation

Many traffic flow parameters affect the performance of the road network at high voltage. These are low vehicle speeds, high vehicle distances relative to road capacity, and density per unit time (lane occupancy). In turn, a number of factors affect the decrease in traffic speed: the presence of slow-moving vehicles in the stream; pedestrians crossing the road irregularly; increase in traffic flow, etc. The issues of public transportation depend on many factors, each of which requires a separate approach and a complex solution. In large cities around the world, the quality indicators of public transport services, including the issues of …


Multi-Mode Regulation Of The Drying Process Of Industrial Gas, Isamidin Xakimovich Sidikov Pr, Nashvandova Gulruxsor Murot Qizi Phd Dec 2023

Multi-Mode Regulation Of The Drying Process Of Industrial Gas, Isamidin Xakimovich Sidikov Pr, Nashvandova Gulruxsor Murot Qizi Phd

Technical science and innovation

Currently, much attention is paid to the issue of energy efficiency of gas processing enterprises. The continuous growth of world prices for energy resources requires constant improvement of the management system, providing the most optimal conditions for the flow of technological processes. A conceptual model of the heat-mass transfer process occurring in the absorber as an object of research has been developed, which characterizes the relationship of the variables involved in the drying process of natural gas, control, measurable and immeasurable, as well as controlled parameters have been selected, which are used to develop and study a mathematical model of …


The Interaction Of The Cotton Piece With The Piles Of The Scrabble Cotton Drum, Fazliddin Egamberdiev, Ilkhom Abbazov, Oybek Kholmuratov, Rashid Kaldybaev Dec 2023

The Interaction Of The Cotton Piece With The Piles Of The Scrabble Cotton Drum, Fazliddin Egamberdiev, Ilkhom Abbazov, Oybek Kholmuratov, Rashid Kaldybaev

Technical science and innovation

This article presents the results of an analytical study of the process of loosening and cleaning raw cotton from small debris by pileging working bodies of purifiers, on the basis of which directions for further research were chosen to optimize the parameters of the developed pile drum with spherical piles and rubber strips. Cotton entering production contains impurities. The processes of loosening and cleaning the fiber shreds are key in the initial stages of ginning, as they prepare the raw cotton for ginning and directly affect the reliability, productivity of these processes and the quality of the resulting fiber. Weed …


An Experimental Investigation Of The New Vibration Viscometer, Jamshidbek Ulugbek Ugli Shamuratov Dec 2023

An Experimental Investigation Of The New Vibration Viscometer, Jamshidbek Ulugbek Ugli Shamuratov

Technical science and innovation

The characteristics of the new oscillating-plate viscometer have been investigated experimentally. The results obtained are as follows: the resonant frequency of plate oscillation decreases with increasing viscosity; the apparatus constant 𝐾 determined experimentally includes the end and slip effects; the dimensions of the plate should be determined by referring to empirical relations between 𝜌𝜇 and Λ(≡{(𝐸𝑎𝐸)−1}𝑛) for various dimensions of the plate; where 𝜌 is the density, 𝜇 is the viscosity; 𝐸𝑎 the resonant amplitude of plate in the air; E the amplitude of plate in a liquid, and 𝑛 a constant. If the distance between the plate and the …


Adaptation Algorithm For Self-Tuning Of Parameters Of Models Of Multi-Stage Flotation Processes, Nilufar Sharifzhanova, Maksadhan Yakubov, Francesco Gregoretti Dec 2023

Adaptation Algorithm For Self-Tuning Of Parameters Of Models Of Multi-Stage Flotation Processes, Nilufar Sharifzhanova, Maksadhan Yakubov, Francesco Gregoretti

Technical science and innovation

Modern methods for solving problems of planning the execution of batches of tasks in multi-stage systems are characterized by the presence of restrictions on their dimensionality, the impossibility of guaranteed obtaining better results in comparison with fixed packages for different values of the input parameters of the problem. In the article, the author solved the problem of optimizing the composition of job packages running in multi-stage systems using the branch and bound method. Research has been carried out on various ways to form package execution orders tasks in multi-stage systems (heuristic rules for ordering packages tasks in the sequence of …


Numerical Study Of Owls' Leading-Edge Serrations, Asif Shahriar Nafi, Nikolaos Beratlis, Elias Balaras, Roi Gurka Dec 2023

Numerical Study Of Owls' Leading-Edge Serrations, Asif Shahriar Nafi, Nikolaos Beratlis, Elias Balaras, Roi Gurka

Physics and Engineering Science

Owls' silent flight is commonly attributed to their special wing morphology combined with wingbeat kinematics. One of these special morphological features is known as the leading-edge serrations: rigid miniature hook-like patterns found at the primaries of the wings' leading-edge. It has been hypothesized that leading-edge serrations function as a passive flow control mechanism, impacting the aerodynamic performance. To elucidate the flow physics associated with owls' leading-edge serrations, we investigate the flow-field characteristic around a barn owl wing with serrated leading-edge geometry positioned at 20° angle of attack for a Reynolds number of 40 000. We use direct numerical simulations, where …


Aerodynamic Dimpling For The Nose Cone Of A High-Power Competition Rocket, Graham Geoffrey Monroe Dec 2023

Aerodynamic Dimpling For The Nose Cone Of A High-Power Competition Rocket, Graham Geoffrey Monroe

Mechanical Engineering ETDs

This thesis investigates nose cone dimpling for the reduction of the aerodynamic drag of a Level 3 High-Power amateur rocket. Two rocket launches were conducted. The first used a COTS nose cone with a smooth surface. A dimple distribution was created according to dimensions calculated by Sandia National Laboratories’ proprietary Right- Size Dimple Evaluator. A dimpled nose cone, designed with geometry matching the COTS component, was 3D printed. Axial acceleration and barometric pressure data, recorded by an onboard flight computer, were used to calculate and plot the drag coefficient as a function of the Reynolds number for the smooth and …


Stochastic Point Process Modeling For Engineering Applications, Samarth Motagi Dec 2023

Stochastic Point Process Modeling For Engineering Applications, Samarth Motagi

Doctoral Dissertations and Master's Theses

Hawkes model or self-exciting point process model is a branching point process model. The model classifies the dataset of discrete events to background and offspring events. It has been used to study interconnected events in many fields, but relatively little work exists in applying these concepts to engineering problems. In our research, we use a self-exciting point process model for two engineering applications: (a) To identify secondary crashes from a given traffic data and (b) To quantify the agglomeration state and size of nanoparticles from computationally generated carbon nanotube microstructure using stochastic percolation model and experimentally generated titanium nanoparticle microstructures. …


Deep-Learning Based Multiple-Model Bayesian Architecture For Spacecraft Fault Estimation, Rocio Jado Puente Dec 2023

Deep-Learning Based Multiple-Model Bayesian Architecture For Spacecraft Fault Estimation, Rocio Jado Puente

Doctoral Dissertations and Master's Theses

This thesis presents recent findings regarding the performance of an intelligent architecture designed for spacecraft fault estimation. The approach incorporates a collection of systematically organized autoencoders within a Bayesian framework, enabling early detection and classification of various spacecraft faults such as reaction-wheel damage, sensor faults, and power system degradation.

To assess the effectiveness of this architecture, a range of performance metrics is employed. Through extensive numerical simulations and in-lab experimental testing utilizing a dedicated spacecraft testbed, the capabilities and accuracy of the proposed intelligent architecture are analyzed. These evaluations provide valuable insights into the architecture's ability to detect and classify …


Verification And Validation Of Robot Manipulator Adaptive Control With Actuator Deficiency, Sebastian Comeaux Dec 2023

Verification And Validation Of Robot Manipulator Adaptive Control With Actuator Deficiency, Sebastian Comeaux

Doctoral Dissertations and Master's Theses

This work addresses the joint tracking problem of robotic manipulators with uncertain dynamical parameters and actuator deficiencies, in the form of an uncertain control effectiveness matrix, through adaptive control design, simulation, and experimentation. Specifically, two novel adaptive controller formulations are implemented and tested via simulation and experimentation. The proposed adaptive control formulations are designed to compensate for uncertainties in the dynamical system parameters as well as uncertainties in the control effectiveness matrix that pre-multiplies the control input. The uncertainty compensation of the dynamical parameters is achieved via the use of the desired model compensation–based adaptation, while the uncertainties related to …


Artificial Intelligence-Assisted Inertial Geomagnetic Passive Navigation, Andrei Cuenca Dec 2023

Artificial Intelligence-Assisted Inertial Geomagnetic Passive Navigation, Andrei Cuenca

Doctoral Dissertations and Master's Theses

In recent years, the integration of machine learning techniques into navigation systems has garnered significant interest due to their potential to improve estimation accuracy and system robustness. This doctoral dissertation investigates the use of Deep Learning combined with a Rao-Blackwellized Particle Filter for enhancing geomagnetic navigation in airborne simulated missions.

A simulation framework is developed to facilitate the evaluation of the proposed navigation system. This framework includes a detailed aircraft model, a mathematical representation of the Earth's magnetic field, and the incorporation of real-world magnetic field data obtained from online databases. The setup allows an accurate assessment of the performance …


Metal Organic Framework Modifications Of Structural Fibers, Marwan Al-Haik Dec 2023

Metal Organic Framework Modifications Of Structural Fibers, Marwan Al-Haik

Publications

A reinforced carbon composite can include a carbon sub­strate and a metal organic framework bonded to the carbon substrate. For example, a reinforced carbon composite can include a first layer, a second layer, and a resin adhered to the first layer and the second layer. The first layer can include a carbon substrate and a metal organic framework bonded to the carbon substrate. The second layer can include a carbon substrate and a metal organic framework bonded to the carbon substrate.


Robotic Arms For Microgravity Manufacturing, Connor Talley, Joshua Diamond, Mickael Bah Dec 2023

Robotic Arms For Microgravity Manufacturing, Connor Talley, Joshua Diamond, Mickael Bah

Senior Design Project For Engineers

There is a need to reduce manufacturing cost in space to avoid sending earth manufactured parts that could suffer damage during launch. The proposed idea consists of a dual robotic arm system attached on a precision gantry setup. The team developed an innovative design that is flexible and efficient for different assemblies, improving space manufacturing. With its two specialized robotic arms, our system maximizes versatility by catering to a wide variety of applications from manufacturing to assembly. The dual arms made of Al 7075 coupled with the gantry provides stability and performance in microgravity environments.


Investigation And Control Of Görtler Vortices In High-Speed Flows, Omar Es-Sahli Dec 2023

Investigation And Control Of Görtler Vortices In High-Speed Flows, Omar Es-Sahli

Theses and Dissertations

High-amplitude freestream turbulence and surface roughness elements can excite a laminar boundary-layer flow sufficiently enough to cause streamwise-oriented vortices to develop. These vortices resemble elongated streaks having alternate spanwise variations of the streamwise velocity. Following the transient growth phase, the fully developed vortex structures downstream undergo an inviscid secondary instability mechanism and, ultimately, transition to turbulence. This mechanism becomes much more complicated in high-speed boundary layer flows due to compressibility and thermal effects, which become more significant for higher Mach numbers. In this research, we formulate and test an optimal control algorithm to suppress the growth rate of the aforementioned …


Comparative Evaluation Of Propulsive Power Transmission Technologies For High-Speed Vertical Takeoff And Landing (Hsvtol) Cargo Aircraft, Xinyu Yang Dec 2023

Comparative Evaluation Of Propulsive Power Transmission Technologies For High-Speed Vertical Takeoff And Landing (Hsvtol) Cargo Aircraft, Xinyu Yang

Doctoral Dissertations and Master's Theses

Designing High-Speed Vertical Takeoff and Landing (HSVTOL) cargo aircraft capable of both low downwash velocity hovering and high subsonic speed cruising presents a significant engineering challenge. This challenge, stemming from conflicting design requirements, has been substantially influenced by recent technological advancements, which have offered greater flexibility in rotor placement. Consequently, this has led to the emergence of innovative mission-specific designs that hold the potential to outperform traditional concepts. The central objective of this study is to evaluate the benefits of modern technologies for VTOL cargo aircraft and assess their performance relative to baseline VTOL aircraft. The results of this comparative …


Development Of A Constellation Simulator For A 5g/Iot Mission Planning System, Franco Criscola Dec 2023

Development Of A Constellation Simulator For A 5g/Iot Mission Planning System, Franco Criscola

Doctoral Dissertations and Master's Theses

The advancement of 5G and Internet-of-Things technologies has presented new challenges for telecommunications providers. One of the challenges is integrating these technologies with present networks. A solution has been found in low-Earth orbit satellite constellations. On one hand, this method increases coverage and reduces costs, but on the other it raises new problems like how to efficiently manage large constellations of spacecraft. This thesis introduces the Constellation Management System, developed in collaboration with i2Cat foundation. This novel tool is composed of two modules: the simulator and the scheduler. The former propagates satellite motion and computes visibility events to various targets …


Experimental And Modelling Of Lightning Damage To Carbon Fibre-Reinforced Composites Under Swept Stroke, Chengzhao Kuang, Kunkun Fu, Juhyeong Lee, Huixin Zhu, Qizhen Shi, Xiaoyu Cui Dec 2023

Experimental And Modelling Of Lightning Damage To Carbon Fibre-Reinforced Composites Under Swept Stroke, Chengzhao Kuang, Kunkun Fu, Juhyeong Lee, Huixin Zhu, Qizhen Shi, Xiaoyu Cui

Mechanical and Aerospace Engineering Faculty Publications

Lightning swept stroke creates multiple lightning attachments along an aircraft in flight. This introduces distinct structural damage compared to that from a single-point lightning current injection test in laboratory. This study presents both experimental and numerical studies on lightning damage in carbon fibre-reinforced polymer (CFRP) composites under swept stroke. Coupled electrical–thermal finite element (FE) models were proposed to predict lightning damage to CFRP composites under single-point current injection and swept stroke, respectively. A lightning swept stroke testing method was proposed by embedding a copper wire inside the composites to simulate multiple lightning attachments on the composites. The FE-predicted damage from …


An Optimization Procedure To Design Nozzle Contours For Hypersonic Wind Tunnels, Omar Antonio Dominguez Dec 2023

An Optimization Procedure To Design Nozzle Contours For Hypersonic Wind Tunnels, Omar Antonio Dominguez

Open Access Theses & Dissertations

Supersonic wind tunnels allow scientists and researchers to evaluate and analyze the behaviors of objects under real-life conditions when subjected to supersonic speeds. One of the main complexities when building a wind tunnel is the design of the convergent-divergent nozzle that is used to produce high-speed and high-quality flows. To achieve supersonic speeds, this nozzle adopts a specialized approach that incorporates the complexities of flow compressibility. The compressible effect is accurately evaluated using isentropic relations, allowing for precise determination of stagnation pressure and temperature, and static pressure and temperature relevant to the desired Mach number. Isentropic equations used to define …


Effects Of Simultaneous Co2 Addition To The Fuel And Oxidizer Streams On Soot Formation In Co-Flow Diffusion Ethylene Flame, Yu Yang, Shu Zheng, Yuzhen He, Hao Liu, Ran Sui, Qiang Lu Dec 2023

Effects Of Simultaneous Co2 Addition To The Fuel And Oxidizer Streams On Soot Formation In Co-Flow Diffusion Ethylene Flame, Yu Yang, Shu Zheng, Yuzhen He, Hao Liu, Ran Sui, Qiang Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Soot formation in a co-flow diffusion ethylene flame with the addition of CO2 to the fuel (the CO2-F), oxidizer (the CO2-O), and fuel/oxidizer (the CO2-F/O) streams was numerically and experimentally investigated in this study. The effects of different CO2 addition ways on soot inception, soot condensation, H-abstraction-C2H2-addition (HACA) and oxidation by O2/OH processes, were quantitatively analyzed by introducing the integrated reaction rates over the whole computational domain. The simulated and experimental results showed that the CO2-F/O was the most effective in inhibiting soot formation …


Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen Dec 2023

Husker Motorsports Active Drag Reduction System, Creighton Hughes, Evan Killian, Micah Busboom, Aj Johnson, Jude Steffen

Honors Theses

Formula SAE is a multifaceted competition that involves student teams designing and competing with an open-wheel style race car. There are 5 different dynamic events included in the competition. Each event requires a unique aerodynamic setup to have the best performance possible. This design project focuses on a drag reduction system (DRS) that will improve aerodynamic performance, resulting in faster lap times and increased competitiveness. Key features include a direct electronic actuation mechanism that will allow the rear wing to be adjusted during a race. The benefits of the DRS system, include increased speed, improved handling, and greater fuel efficiency …


The Afit Engineer, Volume 5, Issue 4, Graduate School Of Engineering And Management, Air Force Institute Of Technology Dec 2023

The Afit Engineer, Volume 5, Issue 4, Graduate School Of Engineering And Management, Air Force Institute Of Technology

AFIT Documents

This issue has a special research feature section by the Autonomy and Navigation Technology Center (ANT) on Demonstration of Alternative Navigation Technologies for Autonomous Aircraft.

Also in this issue:

  • ANT Center lowers DOD dependence on GPS
  • Record number of female Doctorates awarded at AFIT's Fall Commencement
  • D'Azzo Research Library recognized by Library of Congress.
  • Hypersonic vehicle flying qualities assessment
  • Retirement of Dean Badiru

.... and more.


Safe Navigation Of Quadruped Robots Using Density Functions, Andrew Zheng Dec 2023

Safe Navigation Of Quadruped Robots Using Density Functions, Andrew Zheng

All Theses

Safe navigation of mission-critical systems is of utmost importance in many modern autonomous applications. Over the past decades, the approach to the problem has consisted of using probabilistic methods, such as sample-based planners, to generate feasible, safe solutions to the navigation problem. However, these methods use iterative safety checks to guarantee the safety of the system, which can become quite complex. The navigation problem can also be solved in feedback form using potential field methods. Navigation function, a class of potential field methods, is an analytical control design to give almost everywhere convergence properties, but under certain topological constraints and …


Testing And Implementation Of Attitude Determination & Control System For Arksat-1 Cubesatellite, Cassandra Sands Dec 2023

Testing And Implementation Of Attitude Determination & Control System For Arksat-1 Cubesatellite, Cassandra Sands

Graduate Theses and Dissertations

ARKSAT-1 is a CubeSatellite (CubeSat) developed at the University of Arkansas and launched to the International Space Station on SpaceX mission SPX-27 launching from Kennedy Space Center as part of the NASA’s 8th CubeSat Launch Initiative CSLI-8. ARKSAT-1’s payload features a high-powered LED, the Solid State Inflatable Balloon (SSIB) deorbiting system applicable to small satellites, and a series of InfraRed and Visible cameras. To point the LED or take images of desired observational targets, the spacecraft will need to be able to determine its orientation within its orbit, as well as rotate. This will be achieved through the use of …


The Role Of Atomic Layer Deposited Coatings On Lithium-Ion Transport: A Comprehensive Study, Yufang He, Hiep Pham, Xinhua Liang, Jonghyun Park Dec 2023

The Role Of Atomic Layer Deposited Coatings On Lithium-Ion Transport: A Comprehensive Study, Yufang He, Hiep Pham, Xinhua Liang, Jonghyun Park

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Use of Ultrathin Film Coatings Prepared through Atomic Layer Deposition (ALD) Has Become Widespread for Improving Lithium-Ion Diffusivity of Active Particles, Which Plays a Crucial Role in Determining the Rate Capability of Lithium-Ion Batteries (LIBs). in This Study, the Impact of ALD Coating Thickness on Ionic Diffusivity in CeO2-Coated LiMn2O4 (LMO) Cathode Particles is Comprehensively Investigated through First-Principles Calculations by Focusing on the Trade-Offs between the Physical Properties of the Film and its Impact on the Diffusivity of Ions. Our Findings Indicate that Several Physical Factors Affect the Diffusivity of the Coating, Including the Crystal-Amorphous Structure that Depends on …


Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams Dec 2023

Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams

All Dissertations

While Carbon Fiber Reinforced Polymers (CFRPs) have exceptional mechanical properties concerning their overall weight, their failure profile in demanding high-stress environments raises reliability concerns in structural applications. Two crucial limiting factors in CFRP reliability are low-strain material degradation and low fracture toughness. Due to CFRP’s low strain degradation characteristics, a wide variety of interlaminar damage can be sustained without any appreciable change to the physical structure itself. This damage suffered by the energy transfer from high- stress levels appears in the form of microporosity, crazes, microcracks, and delamination in the matrix material before any severe laminate damage is observed. This …