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Articles 6241 - 6270 of 30103

Full-Text Articles in Engineering

Postural Control Differences Between Patients With Posterior Tibial Tendon Dysfunction And Healthy People During Gait, Junsig Wang, L. Daniel Latt, Robert D. Martin, Erin M. Mannen Feb 2022

Postural Control Differences Between Patients With Posterior Tibial Tendon Dysfunction And Healthy People During Gait, Junsig Wang, L. Daniel Latt, Robert D. Martin, Erin M. Mannen

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Background: Patients with posterior tibial tendon dysfunction (PTTD) may exhibit postural instability during walking likely due to a loss of medial longitudinal arch, abnormal foot alignment, and pain. While many studies have investigated gait alterations in PTTD, there is no understanding of dynamic postural control mechanisms in this population during gait, which will help guide rehabilitation and gait training programs for patients with PTTD. The purpose of the study was to assess dynamic postural control mechanisms in patients with stage II PTTD as compared to age and gender matched healthy controls. Methods: Eleven patients with stage II PTTD (4 males …

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Thermoforming Process Effects On Structural Performance Of Carbon Fiber Reinforced Thermoplastic Composite Parts Through A Manufacturing To Response Pathway, Madhura Limaye, Sai Aditya Pradeep, Anmol Kothari, Sushil Savla, Akshat Agha, Srikanth Pilla, Gang Li Feb 2022

Thermoforming Process Effects On Structural Performance Of Carbon Fiber Reinforced Thermoplastic Composite Parts Through A Manufacturing To Response Pathway, Madhura Limaye, Sai Aditya Pradeep, Anmol Kothari, Sushil Savla, Akshat Agha, Srikanth Pilla, Gang Li

Publications

Thermoforming process of thermoplastic-based continuous CFRP's offer a major advantage in reducing cycle times for large-scale productions, but it can also have a significant impact on the structural performance of the parts by inducing undesirable effects. This necessitates the development of an optimal manufacturing process that minimizes the introduction of undesirable factors in the structure and thereby achieves the targeted mechanical performance. This can be done by first establishing a relationship between the manufacturing process and mechanical performance and successively optimizing it to achieve the desired targets. The current study focuses on the former part, where a manufacturing-to-response (MTR) pathway …

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Mass Advection–Diffusion In Creeping Flow Through An Orifice Plate: A Model For Nanoporous Atomically Thin Membranes, Harpreet Atwal, Anika Wong, Michael Boutilier Feb 2022

Mass Advection–Diffusion In Creeping Flow Through An Orifice Plate: A Model For Nanoporous Atomically Thin Membranes, Harpreet Atwal, Anika Wong, Michael Boutilier

Chemical and Biochemical Engineering Publications

Continuum transport equations are commonly applied to nanopores in atomically thin membranes for simple modeling. Although these equations do not apply for nanopores approaching the fluid or solute molecule size, they can be reasonably accurate for larger nanopores. Relatively large graphene nanopores have applications in small particle filtration and appear as unwanted defects in large-area membranes. Solute transport rates through these nanopores determine the rejection performance of the membrane. Atomically thin membranes commonly operate in a regime where advection and diffusion both contribute appreciably to transport. Solute mass transfer rates through larger nanopores have previously been modeled by adding continuum …

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Volumetric Lattice Boltzmann Method For Wall Stresses Of Image-Based Pulsatile Flows, Xiaoyu Zhang, Joan Gomez-Paz, Xi Chen, James M. Mcdonough, Md Mahfuzul Islam, Yiannis Andreopoulos, Luoding Zhu, Huidan Yu Feb 2022

Volumetric Lattice Boltzmann Method For Wall Stresses Of Image-Based Pulsatile Flows, Xiaoyu Zhang, Joan Gomez-Paz, Xi Chen, James M. Mcdonough, Md Mahfuzul Islam, Yiannis Andreopoulos, Luoding Zhu, Huidan Yu

Mechanical Engineering Faculty Publications

Image-based computational fluid dynamics (CFD) has become a new capability for determining wall stresses of pulsatile flows. However, a computational platform that directly connects image information to pulsatile wall stresses is lacking. Prevailing methods rely on manual crafting of a hodgepodge of multidisciplinary software packages, which is usually laborious and error-prone. We present a new computational platform, to compute wall stresses in image-based pulsatile flows using the volumetric lattice Boltzmann method (VLBM). The novelty includes: (1) a unique image processing to extract flow domain and local wall normality, (2) a seamless connection between image extraction and VLBM, (3) an en-route …

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Characterizing The Effect Of Adding Boron Nitride Nanotubes On The Mechanical Properties Of Electrospun Polymer Nanocomposite Microfibers Mesh, Ohood Alsmairat, Nael Barakat Feb 2022

Characterizing The Effect Of Adding Boron Nitride Nanotubes On The Mechanical Properties Of Electrospun Polymer Nanocomposite Microfibers Mesh, Ohood Alsmairat, Nael Barakat

Mechanical Engineering Faculty Publications and Presentations

Electrospun fibrous meshes have a variety of applications such as filtration, drug delivery, energy storage, and engineered tissues due to their high surface area to mass ratio. Therefore, understanding the mechanical properties of these continuously evolving meshes is critical to expand and improve their performance. In this study, the effect of adding Boron Nitride Nanotube (BNNT) to Polymethylmethacrylate (PMMA) composite meshes on the mechanical properties of the polymer is studied. Electrospinning is used to fabricate microfiber meshes of PMMA and BNNT-PMMA. The fabricated meshes are tested experimentally with a uniaxial tensile tester. In addition, a theoretical model is introduced to …

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Utilization Of Triply Periodic Minimal Surface (Tpms) Based Architectures Impregnated With Phase Change Material For Heat Transfer Applications, Zahid Ahmed Qureshi Feb 2022

Utilization Of Triply Periodic Minimal Surface (Tpms) Based Architectures Impregnated With Phase Change Material For Heat Transfer Applications, Zahid Ahmed Qureshi

Dissertations

This dissertation is concerned with the utilization of mathematically architected Triply Periodic Minimal Surface (TPMS) based lattices for Latent Heat Thermal Energy Storage (LHTES) systems. With the advent of Additive Manufacturing (AM), TPMS structures can be readily manufactured. The objective of this dissertation was to investigate the heat transfer performance of TPMS structures vis-à-vis conventional metal foams represented by Kelvin cells while both were impregnated with a Phase Change Material (PCM). Numerical simulations were performed under various boundary conditions to assess the performance. It was found that TPMS structures outperformed conventional metal foam. Moreover, the effects of boundary conditions (isothermal …

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Development Of Zinc Oxide/Hydroxyapatite/Poly(D,L-Lactic Acid) Fibrous Scaffold For Tissue Engineering Applications, Victoria Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Antonio Ledezma-Pérez, Carmen Alvarado-Canché, Raúl Loera-Valencia, Cristóbal Rodríguez, Robert Gilkerson, Carlos Trevino De Leo, Karen Lozano Feb 2022

Development Of Zinc Oxide/Hydroxyapatite/Poly(D,L-Lactic Acid) Fibrous Scaffold For Tissue Engineering Applications, Victoria Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Antonio Ledezma-Pérez, Carmen Alvarado-Canché, Raúl Loera-Valencia, Cristóbal Rodríguez, Robert Gilkerson, Carlos Trevino De Leo, Karen Lozano

Mechanical Engineering Faculty Publications

Scaffolds based on polymeric fibers represent an engaging biomedical device due to their particular morphology and similarity with extracellular matrices. The biggest challenge to use fibrous materials in the biomedical field is related to their favorable platform for the adhesion of pathogenic microorganisms. Therefore, their optimum performance not only depends on their bioactive potential but also on their antimicrobial properties. The aim of this work was the design of antimicrobial (zinc oxide, ZnO) and bioactive (hydroxyapatite, Hap) fibrous materials using poly(D, L-lactic acid) (PDLLA) as the polymer fiber substrate. Fiber based composite scaffolds were developed using the Forcespinning® technique. For …

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Novel Fabrication Of Silver-Coated Copper Nanowires With Organic Compound Solution, Suhyun Lee, Chien Wern, Sung Yi Feb 2022

Novel Fabrication Of Silver-Coated Copper Nanowires With Organic Compound Solution, Suhyun Lee, Chien Wern, Sung Yi

Mechanical and Materials Engineering Faculty Publications and Presentations

Copper nanowires and Cu-Ag nanowires have various potential applications, such as transparent conductive film, flexible electronics, and conductive filler. In this study, we developed a new green fabrication method for silver-coated copper nanowires using methylsulfonylmethane (DMSO2), which is an environmentally friendly chemical at the food-grade level, to replace toxic chemicals, including ammonia, in the silver coating process. Copper nanowires were synthesized under various reaction temperatures and concentrations of hydrazine (N2H4), ethylenediamine (EDA), sodium hydroxide (NaOH), and copper precursor. The reaction temperature higher than 70 C caused the oxidation of copper products and evaporation of the sample solution. The optimal conditions …

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Modeling Data And Reactor Data Associated With The Design, Modeling, And Testing Of The Pressurized Oxy-Coal (Poc) Reactor, Bradley R. Adams, Andrew R. Fry, Dale R. Tree Feb 2022

Modeling Data And Reactor Data Associated With The Design, Modeling, And Testing Of The Pressurized Oxy-Coal (Poc) Reactor, Bradley R. Adams, Andrew R. Fry, Dale R. Tree

ScholarsArchive Data

Data files in the zipped folders below contain research and development information related to the design, modeling, construction and testing of a pressurized, dry feed, oxy-coal reactor at Brigham Young University between 2016 and 2021. The reactor is a once-through system that includes a pressurized dry-coal feed system, a slagging combustion reactor, a spray quench and tube and shell heat exchanger for gas cooling, a cyclone particle collector, and gas depressurization and dilution system. The system is operated with an OPTO22 control system and includes instrumentation to measure gas and wall temperature profiles, radiative heat flux profiles (indicative of flame …

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Effects Of Particle Size Distribution With Efficient Packing On Powder Flowability And Selective Laser Melting Process, Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Lianyi Chen Feb 2022

Effects Of Particle Size Distribution With Efficient Packing On Powder Flowability And Selective Laser Melting Process, Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Lianyi Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The powder bed-based additive manufacturing (AM) process contains uncertainties in the powder spreading process and powder bed quality, leading to problems in repeatability and quality of the additively manufactured parts. This work focuses on identifying the uncertainty induced by particle size distribution (PSD) on powder flowability and the laser melting process, using Ti6Al4V as a model material. The flowability test results show that the effect of PSDs on flowability is not linear, rather the PSDs near dense packing ratios cause significant reductions in flowability (indicated by the increase in the avalanche angle and break energy of the powders measured by …

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Data On The Validation To Determine The Material Thermal Properties Estimation Via A One-Dimensional Transient Convection Model, Lauren B. Tomanek, Daniel S. Stutts Feb 2022

Data On The Validation To Determine The Material Thermal Properties Estimation Via A One-Dimensional Transient Convection Model, Lauren B. Tomanek, Daniel S. Stutts

Mechanical and Aerospace Engineering Faculty Research & Creative Works

These data were acquired to estimate the parameters of a closed form solution of a one-dimensional transient convection heat diffusion PDE. The purpose was to demonstrate that the model could be used to determine the thermal conductivity. The system was tested for a wide range of thermal conductivity, 15-400 W/mK, in order to verify that the method was applicable for various materials. The data reported here refer to the study in the research articles, “Material Thermal Properties Estimation Via a One-Dimensional Transient Convection Model” and “Influence of porosity on the thermal, electrical, and mechanical performance of selective laser melted stainless …

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Effects Of Particle Size Distribution With Efficient Packing On Powder Flowability And Selective Laser Melting Process, Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Lianyi Chen Feb 2022

Effects Of Particle Size Distribution With Efficient Packing On Powder Flowability And Selective Laser Melting Process, Zachary Young, Minglei Qu, Meelap Michael Coday, Qilin Guo, Seyed Mohammad H. Hojjatzadeh, Luis I. Escano, Kamel Fezzaa, Lianyi Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The powder bed-based additive manufacturing (AM) process contains uncertainties in the powder spreading process and powder bed quality, leading to problems in repeatability and quality of the additively manufactured parts. This work focuses on identifying the uncertainty induced by particle size distribution (PSD) on powder flowability and the laser melting process, using Ti6Al4V as a model material. The flowability test results show that the effect of PSDs on flowability is not linear, rather the PSDs near dense packing ratios cause significant reductions in flowability (indicated by the increase in the avalanche angle and break energy of the powders measured by …

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Data On The Validation To Determine The Material Thermal Properties Estimation Via A One-Dimensional Transient Convection Model, Lauren B. Tomanek, Daniel S. Stutts Feb 2022

Data On The Validation To Determine The Material Thermal Properties Estimation Via A One-Dimensional Transient Convection Model, Lauren B. Tomanek, Daniel S. Stutts

Mechanical and Aerospace Engineering Faculty Research & Creative Works

These data were acquired to estimate the parameters of a closed form solution of a one-dimensional transient convection heat diffusion PDE. The purpose was to demonstrate that the model could be used to determine the thermal conductivity. The system was tested for a wide range of thermal conductivity, 15-400 W/mK, in order to verify that the method was applicable for various materials. The data reported here refer to the study in the research articles, "Material Thermal Properties Estimation Via a One-Dimensional Transient Convection Model" [1] and "Influence of porosity on the thermal, electrical, and mechanical performance of selective laser melted …

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An Artificial Intelligence Approach To Fatigue Crack Length Estimation From Acoustic Emission Waves In Thin Metallic Plates, Joseph Chandler Garrett, Hanfei Mei, Victor Giurgiutiu Jan 2022

An Artificial Intelligence Approach To Fatigue Crack Length Estimation From Acoustic Emission Waves In Thin Metallic Plates, Joseph Chandler Garrett, Hanfei Mei, Victor Giurgiutiu

Faculty Publications

The acoustic emission (AE) technique has become a well-established method of monitoring structural health over recent years. The sensing and analysis of elastic AE waves, which have involved piezoelectric wafer active sensors (PWAS) and time domain and frequency domain analysis, has proven to be effective in yielding fatigue crack-related information. However, not much research has been performed regarding (i) the correlation between the fatigue crack length and AE signal signatures and (ii) artificial intelligence (AI) methodologies to automate the AE waveform analysis. In this paper, this crack length correlation is investigated along with the development of a novel AE signal …

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Design Of Broadband Helmholtz Resonator Arrays Using The Radiation Impedance Method, Vidhya Rajendran, Andy Piacsek, Tomás Méndez Echenagucia Jan 2022

Design Of Broadband Helmholtz Resonator Arrays Using The Radiation Impedance Method, Vidhya Rajendran, Andy Piacsek, Tomás Méndez Echenagucia

All Faculty Scholarship for the College of the Sciences

This paper describes the design process of a low-frequency sound absorptive panel composed of differently tuned Helmholtz resonators (HRs), considering size and fabrication constraints relevant for applications in the building sector. The paper focuses on cylindrical and spiral resonators with embedded necks that are thin and can achieve high absorption. the mutual interaction between the resonators was modeled based on the radiation impedance method and it plays a key component in enhancing the absorption performance of the array. The differential evolution search algorithm was used to design the resonators and modify their mutual interaction to derive the absorption performance of …

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Multisector Dynamics: Scientific Challenges And A Research Vision For 2030, A Community Of Practice Supported By The United States Department Of Energy's Office Of Science, Patrick M. Reed, Antonia Hadjimichael, Richard H. Moss, Erwan Monier, Sequoia Alba, Christa Brelsford, Ana Dyreson, Et. Al. Jan 2022

Multisector Dynamics: Scientific Challenges And A Research Vision For 2030, A Community Of Practice Supported By The United States Department Of Energy's Office Of Science, Patrick M. Reed, Antonia Hadjimichael, Richard H. Moss, Erwan Monier, Sequoia Alba, Christa Brelsford, Ana Dyreson, Et. Al.

Michigan Tech Publications, Part 1

No abstract provided.

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A Novel Approach For Real-Time Quality Monitoring In Machining Of Aerospace Alloy Through Acoustic Emission Signal Transformation For Dnn, David Adeniji, Kyle Oligee, Julius Schoop Jan 2022

A Novel Approach For Real-Time Quality Monitoring In Machining Of Aerospace Alloy Through Acoustic Emission Signal Transformation For Dnn, David Adeniji, Kyle Oligee, Julius Schoop

Mechanical Engineering Faculty Publications

Gamma titanium aluminide (γ-TiAl) is considered a high-performance, low-density replacement for nickel-based superalloys in the aerospace industry due to its high specific strength, which is retained at temperatures above 800 °C. However, low damage tolerance, i.e., brittle material behavior with a propensity to rapid crack propagation, has limited the application of γ-TiAl. Any cracks introduced during manufacturing would dramatically lower the useful (fatigue) life of γ-TiAl components, making the workpiece surface’s quality from finish machining a critical component to product quality and performance. To address this issue and enable more widespread use of γ-TiAl, this research aims to develop a …

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A Novel Approach For Real-Time Quality Monitoring In Machining Of Aerospace Alloy Through Acoustic Emission Signal Transformation For Dnn, David Adeniji, Kyle Oligee, Julius Schoop Jan 2022

A Novel Approach For Real-Time Quality Monitoring In Machining Of Aerospace Alloy Through Acoustic Emission Signal Transformation For Dnn, David Adeniji, Kyle Oligee, Julius Schoop

Mechanical Engineering Faculty Publications

Gamma titanium aluminide (γ-TiAl) is considered a high-performance, low-density replacement for nickel-based superalloys in the aerospace industry due to its high specific strength, which is retained at temperatures above 800◦C. However, low damage tolerance, i.e., brittle material behavior with a propensity to rapid crack propagation, has limited the application of γ-TiAl. Any cracks introduced during manufacturing would dramatically lower the useful (fatigue) life of γ-TiAl components, making the workpiece surface’s quality from finish machining a critical component to product quality and performance. To address this issue and enable more widespread use of γ-TiAl, this research aims to develop a real-time …

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Simulation-Aided Development Of A Cnn-Based Vision Module For Plant Detection: Effect Of Travel Velocity, Inferencing Speed, And Camera Configurations, P. R. Sanchez, Hong Zhang Jan 2022

Simulation-Aided Development Of A Cnn-Based Vision Module For Plant Detection: Effect Of Travel Velocity, Inferencing Speed, And Camera Configurations, P. R. Sanchez, Hong Zhang

Henry M. Rowan College of Engineering Departmental Research

In recent years, Convolutional Neural Network (CNN) has become an attractive method to recognize and localize plant species in unstructured agricultural environments. However, developed systems suffer from unoptimized combinations of the CNN model, computer hardware, camera configuration, and travel velocity to prevent missed detections. Missed detection occurs if the camera does not capture a plant due to slow inferencing speed or fast travel velocity. Furthermore, modularity was less focused on Machine Vision System (MVS) development. However, having a modular MVS can reduce the effort in development as it will allow scalability and reusability. This study proposes the derived parameter, called …

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Molecular Dynamic Simulation Of Diffusion In The Melt Pool In Laser Additive Alloying Process Of Co-Ni-Cr-Mn-Fe High Entropy Alloy, Mathew Farias, Han Hu, Shanshan Zhang, Jianzhi Li, Ben Xu Jan 2022

Molecular Dynamic Simulation Of Diffusion In The Melt Pool In Laser Additive Alloying Process Of Co-Ni-Cr-Mn-Fe High Entropy Alloy, Mathew Farias, Han Hu, Shanshan Zhang, Jianzhi Li, Ben Xu

Manufacturing & Industrial Engineering Faculty Publications

High entropy alloys (HEAs) can be manufactured in many conventional ways, but it becomes difficult of fabricating heterogeneous materials and structures. Selective Laser Melting (SLM) method generally melts pure elemental powders or prefabricated alloy powders without alloying process. In-situ alloying in SLM, which is also called Laser Additive Alloying (LAA), using pure elemental powders becomes a promising method for creating HEA with heterogeneous structures. However, the effect of the diffusion of elements in the molten pool on the formation of HEA remains unclear. In this paper, the well-discussed Cantor HEA was studied in an in-situ alloying situation, where pure elemental …

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Strategic Energy Master Planning For Carbon Neutrality, Marie Patterson Jan 2022

Strategic Energy Master Planning For Carbon Neutrality, Marie Patterson

CSU Journal of Sustainability and Climate Change

Universities across the United States are generating goals to be more sustainable and carbon neutral. The energy used in existing buildings on campuses amount to a large volume of greenhouse emissions and must be reduced to help achieve neutrality goals. Strategic Energy Master Plans are instrumental to support these goals through the development of recommendations to reduce energy. Calculating the energy use intensity for existing buildings, a main component of a Strategic Energy Master Plan, can help the campus understand where energy is being used the most. With this information the highest energy consuming buildings can be the focus of …

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Surface Acoustic Wave (Saw) Sensors: Physics, Materials, And Applications, Debdyuti Mandal, Sourav Banerjee Jan 2022

Surface Acoustic Wave (Saw) Sensors: Physics, Materials, And Applications, Debdyuti Mandal, Sourav Banerjee

Faculty Publications

Surface acoustic waves (SAWs) are the guided waves that propagate along the top surface of a material with wave vectors orthogonal to the normal direction to the surface. Based on these waves, SAW sensors are conceptualized by employing piezoelectric crystals where the guided elastodynamic waves are generated through an electromechanical coupling. Electromechanical coupling in both active and passive modes is achieved by integrating interdigitated electrode transducers (IDT) with the piezoelectric crystals. Innovative meta-designs of the periodic IDTs define the functionality and application of SAW sensors. This review article presents the physics of guided surface acoustic waves and the piezoelectric materials …

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Effect Of Defects Part I: Degradation Of Constitutive Coefficients As An Input To The Composite Failure Model With Microvoids And Porosity, Vahid Tavaf, Sourav Banerjee Jan 2022

Effect Of Defects Part I: Degradation Of Constitutive Coefficients As An Input To The Composite Failure Model With Microvoids And Porosity, Vahid Tavaf, Sourav Banerjee

Faculty Publications

It is always challenging to provide appropriate material properties for a composite progressive failure model. The nonstandard percentage reduction method that is commonly used to degrade the material constants with micro-scale defects generates tremendous uncertainty in failure prediction. The constitutive matrix is composed of multiple material constants. It is not necessary that all constants degrade either equally or linearly due to a certain state of material defects. With this very concern in mind, this article presents a guideline for using a quantified perturbation for each coefficient appropriately. It also presents distribution of effective material properties (EMPs) in unidirectional composite materials …

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Analyzing Modeled Torque Profiles To Understand Scale-Dependent Active Muscle Responses In The Hip Joint, Fletcher Young, Hillel J. Chiel, Matthew Tresch, Charles Heckman, Alexander J. Hunt, Roger Quinn Jan 2022

Analyzing Modeled Torque Profiles To Understand Scale-Dependent Active Muscle Responses In The Hip Joint, Fletcher Young, Hillel J. Chiel, Matthew Tresch, Charles Heckman, Alexander J. Hunt, Roger Quinn

Mechanical and Materials Engineering Faculty Publications and Presentations

Animal locomotion is influenced by a combination of constituent joint torques (e.g., due to limb inertia and passive viscoelasticity), which determine the necessary muscular response to move the limb. Across animal size-scales, the relative contributions of these constituent joint torques affect the muscular response in different ways. We used a multi-muscle biomechanical model to analyze how passive torque components change due to an animal’s size-scale during locomotion. By changing the size-scale of the model, we characterized emergent muscular responses at the hip as a result of the changing constituent torque profile. Specifically, we found that activation phases between extensor and …

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Experimental Studies Of Low-Load Limit In A Stoichiometric Micro-Pilot Diesel Natural Gas Engine, Vinicius Bonfochi Vinhaes, Gordon Mctaggart-Cowan, Sandeep Munshi, Mahdi Shahbakhti, Jeffrey Naber Jan 2022

Experimental Studies Of Low-Load Limit In A Stoichiometric Micro-Pilot Diesel Natural Gas Engine, Vinicius Bonfochi Vinhaes, Gordon Mctaggart-Cowan, Sandeep Munshi, Mahdi Shahbakhti, Jeffrey Naber

Michigan Tech Publications, Part 1

While operating at light loads, diesel pilot-ignited natural gas engines with lean pre-mixed natural gas suffer from poor combustion efficiency and high methane emissions. This work investigates the limits of low-load operation for a micro-pilot diesel natural gas engine that uses a stoichiometric mixture to enable methane and nitrogen oxide emission control. By optimizing engine hardware, operating conditions, and injection strategies, this study focused on defining the lowest achievable load while maintaining a stoichiometric equivalence ratio and with acceptable combustion stability. A multi-cylinder diesel 6.7 L engine was converted to run natural gas premix with a maximum diesel micro-pilot contribution …

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Algorithms For Rapid Trip Detection In Human Walking Using Inertial Sensors, Chadi Ellouzi Jan 2022

Algorithms For Rapid Trip Detection In Human Walking Using Inertial Sensors, Chadi Ellouzi

Theses and Dissertations

Trips and falls are one of the most common causes for injuries among elderly. The existing trip-and-falls studies primarily focus on the proactive fall prevention approaches, while active prevention strategies remain largely unexplored. This thesis aims to provide first steps towards active trip-and-fall prevention by developing various algorithms capable of detecting trip in human walking faster than the human voluntary reactions (~200 ms). The measurements of human kinematics are used as the inputs in the algorithms. The proposed algorithms include three threshold-based detection methods, an optimized elastic time-series alignment tool called dynamic time warping (DTW) that overcomes problems of time …

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Matrix Acidizing In Carbonate Formations, Ofelia Gomez Chacon, Maysam Pournik Jan 2022

Matrix Acidizing In Carbonate Formations, Ofelia Gomez Chacon, Maysam Pournik

Mechanical Engineering Faculty Publications

Matrix acidizing in carbonate reservoirs is a process that has been long used to increase productivity in oil and gas producing formations. The main goal is to create wormholes that bypass the damage in the formation. Hydrochloric acid (HCl) is the main acid used for this; however, it has several disadvantages that affect the success of these treatments. Its high reaction rate, inability to divert, and corrosive nature are a few of the reasons why research in this area has focused on finding alternative fluids. This paper discusses studies on successful alternatives to HCl. It has been observed that emulsified …

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Evaluation Of The Accuracy Of Different Pv Estimation Models And The Effect Of Dust Cleaning: Case Study A 103 Mw Pv Plant In Jordan, Loiy Al-Ghussain, Moath Abu Subaih, Andres Annuk Jan 2022

Evaluation Of The Accuracy Of Different Pv Estimation Models And The Effect Of Dust Cleaning: Case Study A 103 Mw Pv Plant In Jordan, Loiy Al-Ghussain, Moath Abu Subaih, Andres Annuk

Mechanical Engineering Graduate Research

The estimation of PV production has been widely investigated previously, where many empirical models have been proposed to account for wind and soiling effects for specific locations. However, the performance of these models varies among the investigated sites. Hence, it is vital to assess and evaluate the performance of these models and benchmark them against the common PV estimation model that accounts only for the ambient temperature. Therefore, this study aims to evaluate the accuracy and performance of four empirical wind models considering the soiling effect, and compare them to the standard model for a 103 MW PV plant in …

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Spatters And Spills: Spreading Dynamics For Partially Wetting Droplets, Sylvia C. L. Durian, Sam Dillavou, Kwame Markin, Adrian Portales, Bryan O. Torres Maldonado, William T. M. Irvine, Paulo E. Arratia, Douglas J. Durian Jan 2022

Spatters And Spills: Spreading Dynamics For Partially Wetting Droplets, Sylvia C. L. Durian, Sam Dillavou, Kwame Markin, Adrian Portales, Bryan O. Torres Maldonado, William T. M. Irvine, Paulo E. Arratia, Douglas J. Durian

Mechanical Engineering Faculty Publications

We present a solvable model inspired by dimensional analysis for the time-dependent spreading of droplets that partially wet a substrate, where the spreading eventually stops and the contact angle reaches a nonzero equilibrium value. We separately consider small droplets driven by capillarity and large droplets driven by gravity. To explore both regimes, we first measure the equilibrium radius vs a comprehensive range of droplet volumes for four household fluids, and we compare the results with predictions based on minimizing the sum of gravitational and interfacial energies. The agreement is good and gives a reliable measurement of an equilibrium contact angle …

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Multi-Objective Optimization On Dimensional Accuracy, Edge And Surface Quality Of 3d-Printed Parts By Fused Deposition Modelling, Islam Hamdy Salem Jan 2022

Multi-Objective Optimization On Dimensional Accuracy, Edge And Surface Quality Of 3d-Printed Parts By Fused Deposition Modelling, Islam Hamdy Salem

Theses and Dissertations

Fused Deposition Modelling (FDM) is one of most common additive manufacturing (AM) techniques used in manufacturing field. It has been increasingly used because of its low cost and simplicity. Although FDM can save time through eliminating pre-processing tooling-up to produce the end-user product, still a better final product quality, like mechanical properties, dimensional accuracy and surface finish, is needed. This thesis addresses the maximization of involved printing parameters in one reliable model. Hence, a wider investigation is conducted in this research via experimental work in order to obtain a comprehensive model that involves and relates more parameters in a single …

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