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Mechanical Engineering

2022

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Full-Text Articles in Engineering

Comparative Analysis Of Injection Of Pyrolysis Oil From Plastics And Gasoline Into The Engine Cylinder And Atomization By A Direct High-Pressure Injector, Magdalena Szwaja, Jeffrey Naber, David Shonnard, Daniel G. Kulas, Ali Zolghadr, Stanislaw Szwaja Dec 2022

Comparative Analysis Of Injection Of Pyrolysis Oil From Plastics And Gasoline Into The Engine Cylinder And Atomization By A Direct High-Pressure Injector, Magdalena Szwaja, Jeffrey Naber, David Shonnard, Daniel G. Kulas, Ali Zolghadr, Stanislaw Szwaja

Michigan Tech Publications

The article discusses the results of experimental studies on the course of pyrolysis oil injection through the high-pressure injector of a direct-injection engine. The pyrolysis oil used for the tests was derived from waste plastics (mainly high-density polyethylene—HDPE). This oil was then distilled. The article also describes the production technology of this pyrolysis oil on a laboratory scale. It presents the results of the chemical composition of the raw pyrolysis oil and the oil after the distillation process using GC-MS analysis. Fuel injection tests were carried out for the distilled pyrolysis oil and a 91 RON gasoline in order to …


Bio-Inspired Micromachined Volumetric Flow Sensor With A Big Dynamic Range For Intravenous Systems, Lansheng Zhang, Yingchen Yang, Georgios A. Bertos, Chang Liu, Huan Hu Dec 2022

Bio-Inspired Micromachined Volumetric Flow Sensor With A Big Dynamic Range For Intravenous Systems, Lansheng Zhang, Yingchen Yang, Georgios A. Bertos, Chang Liu, Huan Hu

Mechanical Engineering Faculty Publications and Presentations

Real-time monitoring of drug delivery in an intravenous infusion system can prevent injury caused by improper drug doses. As the medicine must be administered into the vein at different rates and doses in different people, an ideal intravenous infusion system requires both a low flow rate and large dynamic range monitoring. In this study, a bio-inspired and micromachined volumetric flow sensor is presented for the biomedical application of an intravenous system. This was realized by integrating two sensing units with different sensitivities on one silicon die to achieve a large dynamic range of the volumetric flow rate. The sensor was …


Phase-Averaged, Frequency Dependence Of Jet Dynamics In A Scaled Up Vocal Fold Model With Full And Incomplete Closure, Nathaniel Wei, Abigail Haworth, Hunter Ringenberg, Michael Krane, Timothy Wei Dec 2022

Phase-Averaged, Frequency Dependence Of Jet Dynamics In A Scaled Up Vocal Fold Model With Full And Incomplete Closure, Nathaniel Wei, Abigail Haworth, Hunter Ringenberg, Michael Krane, Timothy Wei

Department of Mechanical and Materials Engineering: Faculty Publications

This study focuses on frequency dependence effects on glottal jet dynamics with a focus on the physiological condition in which the vocal folds do not fully close. Incomplete closure occurs naturally in children and adult females. But there are also pathological conditions that can be problematic. Experiments were conducted using a 10× scaled-up model in a free surface water tunnel. Two-dimensional vocal fold models with semicircular medial surfaces were stepper motor driven inside a square duct with constant opening and closing speeds. Cases with complete vocal fold closure and incomplete closure to only 15% of the maximum gap were examined. …


Sars-Cov-2 Detecting Rapid Metasurface-Based Sensor, Shobhit K. Patel, Jaymit Surve, Juveriya Parmar, Khaled Aliqab, Meshari Alsharari, Ammar Armghan Dec 2022

Sars-Cov-2 Detecting Rapid Metasurface-Based Sensor, Shobhit K. Patel, Jaymit Surve, Juveriya Parmar, Khaled Aliqab, Meshari Alsharari, Ammar Armghan

Department of Mechanical and Materials Engineering: Faculty Publications

We have proposed a novel approach to detect COVID-19 by detecting the ethyl butanoate which high volume ratio is present in the exhaled breath of a COVID-19 infected person. We have employed a refractive index sensor (RIS) with the help of a metasurface-based slotted T-shape perfect absorber that can detect ethyl butanoate present in exhaled breath of COVID-19 infected person with high sensitivity and in-process SARS-CoV-2. The optimized structure of the sensor is obtained by varying several structure parameters including structure length and thickness, slotted T-shape resonator length, width, and thickness. Sensor’s performance is evaluated based on numerous factors comprising …


Wind-Powered Continuous Reverse Osmosis Water Desalination, Aliah Adriana Binti Khairul Hisham Dec 2022

Wind-Powered Continuous Reverse Osmosis Water Desalination, Aliah Adriana Binti Khairul Hisham

Discovery Undergraduate Interdisciplinary Research Internship

Water scarcity is a grave issue that is faced by lots of people worldwide. This phenomenon is further exacerbated by climate change, overpopulation, and water-intense industrial activities. To combat this issue, reverse osmosis (RO) water desalination system is broadly introduced in order to produce freshwater while maintaining the desired thermodynamic efficiency and economic feasibility. RO water desalination is a process of separating freshwater from salt water using a semi-permeable membrane. In status quo, there are various forms of energy present in RO system (e.g: hydraulic, mechanical, electrical energy, etc.) to power the hydraulic components. The conversion from one form of …


Retention Forces For Drops On Microstructured Superhydrophobic Surfaces, Shaur Humayun, R. Daniel Maynes, Julie Crockett, Brian D. Iverson Dec 2022

Retention Forces For Drops On Microstructured Superhydrophobic Surfaces, Shaur Humayun, R. Daniel Maynes, Julie Crockett, Brian D. Iverson

Faculty Publications

Accurate models of retention forces between drops and superhydrophobic (SH) surfaces are required to predict drop dynamics on the surface. This retention force is, in turn, useful in modeling heat transfer rates for dropwise condensation on a SH surface. Drop contact angle distribution and base area on SH surfaces are essential factors for predicting retention forces. The present work measures the contact angle distribution and base area shapes of various drop sizes over a wide range of solid fraction for inclined microstructured SH surfaces at the point of drop departure. Base area shape was found to be well approximated using …


Nanoscale Imaging Of Antiferromagnetic Domains In Epitaxial Films Of Cr2O3 Via Scanning Diamond Magnetic Probe Microscopy, Adam Erickson, Syed Qamar Abbas Shah, Ather Mahmood, Ilja Fescenko, Christian H. Binek, Adbelghani Laraoui Dec 2022

Nanoscale Imaging Of Antiferromagnetic Domains In Epitaxial Films Of Cr2O3 Via Scanning Diamond Magnetic Probe Microscopy, Adam Erickson, Syed Qamar Abbas Shah, Ather Mahmood, Ilja Fescenko, Christian H. Binek, Adbelghani Laraoui

Department of Mechanical and Materials Engineering: Faculty Publications

We report direct imaging of boundary magnetization associated with antiferromagnetic domains in magnetoelectric epitaxial Cr2O3 thin films using diamond nitrogen vacancy microscopy. We found a correlation between magnetic domain size and structural grain size which we associate with the domain formation process. We performed field cooling, i.e., cooling from above to below the Néel temperature in the presence of a magnetic field, which resulted in the selection of one of the two otherwise degenerate 180° domains. Lifting of such a degeneracy is achievable with a magnetic field alone due to the Zeeman energy of a weak …


Biomechanical And Sensory Feedback Regularize The Behavior Of Different Locomotor Central Pattern Generators, Kaiyu Deng, Alexander J. Hunt, Nicholas Szczecinski, Matthew Tresch, Hillel J. Chiel, Charles Heckman, Roger Quinn Dec 2022

Biomechanical And Sensory Feedback Regularize The Behavior Of Different Locomotor Central Pattern Generators, Kaiyu Deng, Alexander J. Hunt, Nicholas Szczecinski, Matthew Tresch, Hillel J. Chiel, Charles Heckman, Roger Quinn

Mechanical and Materials Engineering Faculty Publications and Presentations

This work presents an in-depth numerical investigation into a hypothesized two-layer central pattern generator (CPG) that controls mammalian walking and how different parameter choices might affect the stepping of a simulated neuromechanical model. Particular attention is paid to the functional role of features that have not received a great deal of attention in previous work: the weak cross-excitatory connectivity within the rhythm generator and the synapse strength between the two layers. Sensitivity evaluations of deafferented CPG models and the combined neuromechanical model are performed. Locomotion frequency is increased in two different ways for both models to investigate whether the model’s …


Out Of The Wood: Sojurn Cyclery, Jay H. Kinsinger Dec 2022

Out Of The Wood: Sojurn Cyclery, Jay H. Kinsinger

Engineering and Computer Science Faculty Contributions to the Popular Press

No abstract provided.


High Throughput And Highly Controllable Methods For In Vitro Intracellular Delivery, Justin Brooks, Grayson Minnick, Prithvijit Mukherjee, Arian Jaberi, Lingqian Chang, Horacio D. Espinosa, Ruiguo Yang Dec 2022

High Throughput And Highly Controllable Methods For In Vitro Intracellular Delivery, Justin Brooks, Grayson Minnick, Prithvijit Mukherjee, Arian Jaberi, Lingqian Chang, Horacio D. Espinosa, Ruiguo Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In vitro and ex vivo intracellular delivery methods hold the key for releasing the full potential of tissue engineering, drug development, and many other applications. In recent years, there has been significant progress in the design and implementation of intracellular delivery systems capable of delivery at the same scale as viral transfection and bulk electroporation but offering fewer adverse outcomes. This review strives to examine a variety of methods for in vitro and ex vivo intracellular delivery such as flow-through microfluidics, engineered substrates, and automated probe-based systems from the perspective of throughput and control. Special attention is paid to a …


Prediction Of Meltpool Depth In Laser Powder Bed Fusion Using In-Process Sensor Data, Part-Level Thermal Simulations, And Machine Learning, Grant King Dec 2022

Prediction Of Meltpool Depth In Laser Powder Bed Fusion Using In-Process Sensor Data, Part-Level Thermal Simulations, And Machine Learning, Grant King

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The goal of this thesis is the prevention of flaw formation in laser powder bed fusion additive manufacturing process. As a step towards this goal, the objective of this work is to predict meltpool depth as a function of in-process sensor data, part-level thermal simulations, and machine learning. As motivated in NASA's Marshall Space Flight Center specification 3716, prediction of meltpool depth is important because: (1) it can serve as a surrogate to estimate process status without the need for expensive post-process characterization, and (2) the meltpool depth provides an avenue for rapid qualification of microstructure evolution. To achieve the …


Study On The Spatiotemporal Dynamic Of Ground-Level Ozone Concentrations On Multiple Scales Across China During The Blue Sky Protection Campaign, Haoji Wu, Lin Pei, Xiaowei Zhu, Bin Guo, Dingming Zhang, Multiple Additional Authors Dec 2022

Study On The Spatiotemporal Dynamic Of Ground-Level Ozone Concentrations On Multiple Scales Across China During The Blue Sky Protection Campaign, Haoji Wu, Lin Pei, Xiaowei Zhu, Bin Guo, Dingming Zhang, Multiple Additional Authors

Mechanical and Materials Engineering Faculty Publications and Presentations

Surface ozone (O3), one of the harmful air pollutants, generated significantly negative effects on human health and plants. Existing O3 datasets with coarse spatiotemporal resolution and limited coverage, and the uncertainties of O3 influential factors seriously restrain related epidemiology and air pollution studies. To tackle above issues, we proposed a novel scheme to estimate daily O3 concentrations on a fine grid scale (1 km × 1 km) from 2018 to 2020 across China based on machine learning methods using hourly observed ground-level pollutant concentrations data, meteorological data, satellite data, and auxiliary data including digital elevation model (DEM), land use …


Architectural Control Of Mesenchymal Stem Cell Phenotype Through Nuclear Actin, Janet Rubin, Andre J. Van Wijnen, Gunes Uzer Dec 2022

Architectural Control Of Mesenchymal Stem Cell Phenotype Through Nuclear Actin, Janet Rubin, Andre J. Van Wijnen, Gunes Uzer

Mechanical and Biomedical Engineering Faculty Publications and Presentations

There is growing appreciation that architectural components of the nucleus regulate gene accessibility by altering chromatin organization. While nuclear membrane connector proteins link the mechanosensitive actin cytoskeleton to the nucleoskeleton, actin’s contribution to the inner architecture of the nucleus remains enigmatic. Control of actin transport into the nucleus, plus the presence of proteins that control actin structure (the actin tool-box) within the nucleus, suggests that nuclear actin may support biomechanical regulation of gene expression. Cellular actin structure is mechanoresponsive: actin cables generated through forces experienced at the plasma membrane transmit force into the nucleus. We posit that dynamic actin remodeling …


Parametric Modeling Of Biomimetic Sharkskin For Wire Edm For Drag Reduction And Hydrophobicity, Joel Maxwell Dec 2022

Parametric Modeling Of Biomimetic Sharkskin For Wire Edm For Drag Reduction And Hydrophobicity, Joel Maxwell

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This research sets out to demonstrate the viability of parametric modeling for biomimetic sharkskin in the effort to reduce drag and create a self-cleaning surface. Multiple designs were created to be machined by Wire EDM on stainless steel and titanium and were comparatively tested. Limitations of current manufacturing processes to economically produce naturally occurring structures such as sharkskin, emphasize the need to be able to calculate the most accurate design for a given manufacturing process. By designing a simplified but parametrically consistent model compared to an accurately depicted 3D model of sharkskin, the textured samples produced can be further tested …


Development And Characterization Of Forcespinning® Mesquite Gum Nanofibers, Cristobal Rodriguez, Victoria I. Padilla, Karen Lozano, Alexa Villarreal, Luis A. Materon, Robert Gilkerson Dec 2022

Development And Characterization Of Forcespinning® Mesquite Gum Nanofibers, Cristobal Rodriguez, Victoria I. Padilla, Karen Lozano, Alexa Villarreal, Luis A. Materon, Robert Gilkerson

Mechanical Engineering Faculty Publications and Presentations

In this study, nanofibers incorporating Prosopis glandulosa mesquite gum (MG) exudate combined with biodegradable polymers, pullulan (PL) and chitosan (CH), were produced via the Forcespinning® technique. The nonwoven composite membranes were characterized via scanning electron microscopy followed by thermogravimetric and Fourier-transform infrared spectroscopy analysis. MG nanofiber composites comprised long, continuous fibers with an average fiber diameter of 523 ± 180 nm and 760 ± 225 nm for 18.1 and 28 wt% of MG, respectively. These composite membranes were water-stable after crosslinking via heat treatment with a ∼3 % water absorption capacity, and demonstrated a thermal capability with an increasing …


Machine Learning-Based Classification Of Combustion Events In An Rcci Engine Using Heat Release Rate Shapes, Radhika Sitaraman, Sadaf Batool, Hoseinali Borhan, Javad Mohammadpour Velni, Jeffrey Naber, Mahdi Shahbakhti Nov 2022

Machine Learning-Based Classification Of Combustion Events In An Rcci Engine Using Heat Release Rate Shapes, Radhika Sitaraman, Sadaf Batool, Hoseinali Borhan, Javad Mohammadpour Velni, Jeffrey Naber, Mahdi Shahbakhti

Michigan Tech Publications

Reactivity controlled compression ignition (RCCI) mode offers high thermal efficiency and low nitrogen oxides (NOx) and soot emissions. However, high cyclic variability at low engine load and high pressure rise rates at high loads limit RCCI operation. Therefore, it is important to control the combustion event in an RCCI engines to prevent abnormal engine combustion. To this end, combustion in RCCI mode was studied by analyzing the heat release rates calculated from the in-cylinder pressure data at 798 different operating conditions. Five distinct heat release shapes are identified. These different heat release traces were characterized based on start of combustion, …


Efects Of Non‑Newtonian Viscosity On Arterial And Venous Fow And Transport, Sabrina Lynch, Nitesh Nama, C Alberto Figueroa Nov 2022

Efects Of Non‑Newtonian Viscosity On Arterial And Venous Fow And Transport, Sabrina Lynch, Nitesh Nama, C Alberto Figueroa

Department of Mechanical and Materials Engineering: Faculty Publications

It is well known that blood exhibits non-Newtonian viscosity, but it is generally modeled as a Newtonian fluid. However, in situations of low shear rate, the validity of the Newtonian assumption is questionable. In this study, we investigated differences between Newtonian and non-Newtonian hemodynamic metrics such as velocity, vorticity, and wall shear stress. In addition, we investigated cardiovascular transport using two different approaches, Eulerian mass transport and Lagrangian particle tracking. Non-Newtonian solutions revealed important differences in both hemodynamic and transport metrics relative to the Newtonian model. Most notably for the hemodynamic metrics, in-plane velocity and vorticity were consistently larger in …


Prediction Of Curing Time/Shear Strength Of Non-Conductive Adhesives Using A Neural Network Model, Kyung-Eun Min, Jae-Won Jang, Jun-Ki Kim, Sung Yi, Cheolhee Kim Nov 2022

Prediction Of Curing Time/Shear Strength Of Non-Conductive Adhesives Using A Neural Network Model, Kyung-Eun Min, Jae-Won Jang, Jun-Ki Kim, Sung Yi, Cheolhee Kim

Mechanical and Materials Engineering Faculty Publications and Presentations

Electronic packaging has been developed with high resolution and fine interconnection pitches. Non-conductive adhesives (NCAs) have been growing with the increase of I/O pad count and density, along with fine pad bond pitch interconnections. Prediction and optimization of NCA characteristics are inherently complicated due to various and extensive materials composing NCAs. In this study, a framework predicting the curing time and shear strength of an NCA is established by a neural network model. NCA formulations with 4 resins, 3 hardeners, 8 catalysts, and a coupling agent were selected from in-house experiments, and an artificial neural network (ANN) with one dense …


Enhanced Electron Correlation And Significantly Suppressed Thermal Conductivity In Dirac Nodal-Line Metal Nanowires By Chemical Doping, Amanda L. Coughlin, Zhiliang Pan, Jeonghoon Hong, Tongxie Zhang, Xun Zhan, Wenqian Wu, Dongyue Xie, Tian Tong, Thomas Ruch, Jean J. Heremans, Jiming Bao, Herbert A. Fertig, Jian Wang, Jeongwoo Kim, Hanyu Zhu, Deyu Li, Shixiong Zhang Nov 2022

Enhanced Electron Correlation And Significantly Suppressed Thermal Conductivity In Dirac Nodal-Line Metal Nanowires By Chemical Doping, Amanda L. Coughlin, Zhiliang Pan, Jeonghoon Hong, Tongxie Zhang, Xun Zhan, Wenqian Wu, Dongyue Xie, Tian Tong, Thomas Ruch, Jean J. Heremans, Jiming Bao, Herbert A. Fertig, Jian Wang, Jeongwoo Kim, Hanyu Zhu, Deyu Li, Shixiong Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

Enhancing electron correlation in a weakly interacting topological system has great potential to promote correlated topological states of matter with extraordinary quantum properties. Here, the enhancement of electron correlation in a prototypical topological metal, namely iridium dioxide (IrO2), via doping with 3d transition metal vanadium is demonstrated. Single-crystalline vanadium-doped IrO2 nanowires are synthesized through chemical vapor deposition where the nanowire yield and morphology are improved by creating rough surfaces on substrates. Vanadium doping leads to a dramatic decrease in Raman intensity without notable peak broadening, signifying the enhancement of electron correlation. The enhanced electron correlation is further …


Exosomes Derived From Differentiated Human Admsc With The Schwann Cell Phenotype Modulate Peripheral Nerve-Related Cellular Functions, Bo Liu, Yunfan Kong, Wen Shi, Mitchell Kuss, Ke Liao, Guoku Hu, Peng Xiao, Jagadesan Sankarasubramanian, Chittibabu Guda, Xinglong Wang, Yuguo Lei, Bin Duan Nov 2022

Exosomes Derived From Differentiated Human Admsc With The Schwann Cell Phenotype Modulate Peripheral Nerve-Related Cellular Functions, Bo Liu, Yunfan Kong, Wen Shi, Mitchell Kuss, Ke Liao, Guoku Hu, Peng Xiao, Jagadesan Sankarasubramanian, Chittibabu Guda, Xinglong Wang, Yuguo Lei, Bin Duan

Department of Mechanical and Materials Engineering: Faculty Publications

Peripheral nerve regeneration remains a significant clinical challenge due to the unsatisfactory functional recovery and public health burden. Exosomes, especially those derived from mesenchymal stem cells (MSCs), are promising as potential cell-free therapeutics and gene therapy vehicles for promoting neural regeneration. In this study, we reported the differentiation of human adipose derived MSCs (hADMSCs) towards the Schwann cell (SC) phenotype (hADMSC-SCs) and then isolated exosomes from hADMSCs with and without differentiation (i.e., dExo vs uExo). We assessed and compared the effects of uExo and dExo on antioxidative, angiogenic, antiinflammatory, and axon growth promoting properties by using various peripheral nerve-related cells. …


A Novel Voc Breath Tracer Method To Evaluate Indoor Respiratory Exposures In The Near- And Far-Fields; Implications For The Spread Of Respiratory Viruses, Hooman Parhizkar, Mark Fretz, Aurelie Laguerre, Jason Stenson, Richard Corsi, Kevin Van Den Wymelenberg, Elliott T. Gall Nov 2022

A Novel Voc Breath Tracer Method To Evaluate Indoor Respiratory Exposures In The Near- And Far-Fields; Implications For The Spread Of Respiratory Viruses, Hooman Parhizkar, Mark Fretz, Aurelie Laguerre, Jason Stenson, Richard Corsi, Kevin Van Den Wymelenberg, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Background

Several studies suggest that far-field transmission (>6 ft) explains a significant number of COVID-19 superspreading outbreaks.

Objective

Therefore, quantifying the ratio of near- and far-field exposure to emissions from a source is key to better understanding human-to-human airborne infectious disease transmission and associated risks.

Methods

In this study, we used an environmentally-controlled chamber to measure volatile organic compounds (VOCs) released from a healthy participant who consumed breath mints, which contained unique tracer compounds. Tracer measurements were made at 0.76 m (2.5 ft), 1.52 m (5 ft), 2.28 m (7.5 ft) from the participant, as well as in the …


Wind Tunnel Research, Dynamics, And Scaling For Wind Energy, Majid Bastankhah, Raul Bayoan Cal, Nicholas Hamilton Nov 2022

Wind Tunnel Research, Dynamics, And Scaling For Wind Energy, Majid Bastankhah, Raul Bayoan Cal, Nicholas Hamilton

Mechanical and Materials Engineering Faculty Publications and Presentations

The interaction of wind turbines with turbulent atmospheric boundary layer (ABL) flows represents a complex multi-scale problem that spans several orders of magnitudes of spatial and temporal scales. These scales range from the interactions of large wind farms with the ABL (on the order of tens of kilometers) to the small length scale of the wind turbine blade boundary layer (order of a millimeter). Detailed studies of multi-scale wind energy aerodynamics are timely and vital to maximize the efficiency of current and future wind energy projects, be they onshore, bottom-fixed offshore, or floating offshore. Among different research modalities, wind tunnel …


Wind Plant Controls, Nicholas Hamilton, Dennice Gayme, Raúl Bayoán Cal Nov 2022

Wind Plant Controls, Nicholas Hamilton, Dennice Gayme, Raúl Bayoán Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

The development of operational strategies for wind farms as an integrated plant system to achieve a variety of goals from elevating power production to reducing maintenance needs has generated a great deal of interest in recent years. Achieving these operational goals requires an estimate of the energy available and the wind conditions affecting each turbine. The importance of the aerodynamic interaction of wind turbines with the dynamic atmospheric resource means that wakes (the momentum deficit due to power extraction) and their interactions through the farm have the largest influence on the available energy. Predicting the influence of wakes and their …


Remote Sensing Evidence For Significant Variations In The Global Gross Domestic Product During The Covid-19 Epidemic, Bin Guo, Wencai Zhang, Lin Pei, Xiaowei Zhu, Pingping Luo, Weili Duan Nov 2022

Remote Sensing Evidence For Significant Variations In The Global Gross Domestic Product During The Covid-19 Epidemic, Bin Guo, Wencai Zhang, Lin Pei, Xiaowei Zhu, Pingping Luo, Weili Duan

Mechanical and Materials Engineering Faculty Publications and Presentations

Coronavirus disease 2019 (COVID-19) has been spreading rapidly and is still threatening human health currently. A series of measures for restraining epidemic spreading has been adopted throughout the world, which seriously impacted the gross domestic product (GDP) globally. However, details of the changes in the GDP and its spatial heterogeneity characteristics on a fine scale worldwide during the pandemic are still uncertain. We designed a novel scheme to simulate a 0.1° × 0.1° resolution grid global GDP map during the COVID-19 pandemic. Simulated nighttime-light remotely sensed data (SNTL) was forecasted via a GM(1, 1) model under the assumption that there …


Phase Space Analysis Of Nonlinear Wave Propagation In A Bistable Mechanical Metamaterial With A Defect, Mohammed A. Mohammed, Piyush Grover Nov 2022

Phase Space Analysis Of Nonlinear Wave Propagation In A Bistable Mechanical Metamaterial With A Defect, Mohammed A. Mohammed, Piyush Grover

Department of Mechanical and Materials Engineering: Faculty Publications

We study the dynamics of solitary waves traveling in a one-dimensional chain of bistable elements in the presence of a local inhomogeneity (“defect”). Numerical simulations reveal that depending upon its initial speed, an incoming solitary wave can get transmitted, captured, or reflected upon interaction with the defect. The dynamics are dominated by energy exchange between the wave and a breather mode localized at the defect. We derive a reduced-order two degree of freedom Hamiltonian model for wave-breather interaction and analyze it using dynamical systems techniques. Lobe dynamics analysis reveals the fine structure of phase space that leads to the complicated …


Feedforward Control Of Thermal History In Laser Powder Bed Fusion: Toward Physics-Based Optimization Of Processing Parameters, Alex Riensche, Benjamin D. Bevans, Ziyad M. Smoqi, Reza Yavari, Ajay Krishnan, Josie Gilligan, Nicholas Piercy, Kevin D. Cole, Prahalada K. Rao Nov 2022

Feedforward Control Of Thermal History In Laser Powder Bed Fusion: Toward Physics-Based Optimization Of Processing Parameters, Alex Riensche, Benjamin D. Bevans, Ziyad M. Smoqi, Reza Yavari, Ajay Krishnan, Josie Gilligan, Nicholas Piercy, Kevin D. Cole, Prahalada K. Rao

Department of Mechanical and Materials Engineering: Faculty Publications

We developed and applied a model-driven feedforward control approach to mitigate thermal-induced flaw formation in laser powder bed fusion (LPBF) additive manufacturing process. The key idea was to avert heat buildup in a LPBF part before it is printed by adapting process parameters layer-by-layer based on insights from a physics-based thermal simulation model. The motivation being to replace cumbersome empirical build-and-test parameter optimization with a physics-guided strategy. The approach consisted of three steps: prediction, analysis, and correction. First, the temperature distribution of a part was predicted rapidly using a graph theory-based computational thermal model. Second, the model-derived thermal trends were …


Changing Climates And Extreme Weather For Minnesota, Patrick A. Tebbe Nov 2022

Changing Climates And Extreme Weather For Minnesota, Patrick A. Tebbe

Mechanical and Civil Engineering Department Publications

Climate change is impacting the design, prediction, and operation of HVAC systems for the built environment, and will continue to do so for the foreseeable future. This presentation reviews climate predictions for the upper Midwest and how they will affect the HVAC industry. Topics such as changing design conditions, extreme weather impact, and increased electrification will be addressed.


Elastomer O-Ring Seal Swell Measurements For Sustainable Aviation Fuel Material Compatibility, Conor J. Faulhaber Nov 2022

Elastomer O-Ring Seal Swell Measurements For Sustainable Aviation Fuel Material Compatibility, Conor J. Faulhaber

Honors Theses

As efforts continue to fight climate change by transitioning energy sources away from fossil fuels and towards renewable alternative, the commercial aviation sector finds itself at danger of falling behind in emissions reductions. To combat this, the best term opportunity to reduce the industry’s contribution to greenhouse gas emissions has been identified as sustainable aviation fuel, or SAF, derived from renewable feedstocks like agricultural waste or used cooking oil. Currently, SAF is regulated to a 50%v blending limit with conventional petroleum-based fuel to maintain certain jet fuel properties, including material compatibility with elastomer o-ring seals. When these seals come in …


Ai-Enabled Droplet Detection And Tracking For Agricultural Spraying Systems, Praneel Acharya, Travis A. Burgers, Doang Nguyen Nov 2022

Ai-Enabled Droplet Detection And Tracking For Agricultural Spraying Systems, Praneel Acharya, Travis A. Burgers, Doang Nguyen

Mechanical Engineering Faculty Publications

his work leverages recent advancements in com- puter vision and deep learning to detect and track the motion of droplets captured by a camera. While classical computer vision techniques have been employed for detection and tracking, those approaches have limitations and are not trivially extended to droplets. We approach the problems of droplet detection and tracking through a data-driven framework, in which an annotated database of droplet images is built and object detection and tracking models are trained on this database. The accuracy of the model is evaluated and the whole process is discussed. At this point, droplet geometric properties …


Using Strategic Options Development And Analysis (Soda) To Understand The Simulation Accessibility Problem, Andrew J. Collins, Ying Thaviphoke, Antuela A. Tako Nov 2022

Using Strategic Options Development And Analysis (Soda) To Understand The Simulation Accessibility Problem, Andrew J. Collins, Ying Thaviphoke, Antuela A. Tako

Engineering Management & Systems Engineering Faculty Publications

Simulation modelling is applied to a wide range of problems, including defense and healthcare. However, there is a concern within the simulation community that there is a limited use and implementation of simulation studies in practice. This suggests that despite its benefits, simulation may not be reaching its potential in making a real-world impact. The main reason for this could be that simulation tools are not widely accessible in industry. In this paper, we investigate the issues that affect simulation modelling accessibility through a workshop with simulation practitioners. We use Strategic Options Development and Analysis (SODA), a problem-structuring approach that …