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Articles 6121 - 6150 of 29998

Full-Text Articles in Mechanical Engineering

Effect Of Indentation On Sandwich Composite Structure Mechanical Behavior, Marius V. Jatulis Mar 2022

Effect Of Indentation On Sandwich Composite Structure Mechanical Behavior, Marius V. Jatulis

Master's Theses

Composite sandwich structures are prevalent in engineering applications where high strength to weight ratios are critical. A composite sandwich includes the addition of a core material between two composite face sheets to increase ultimate stress in compression and bending loading cases. The performance of many composite sandwich structure configurations is well understood in the undamaged case. This analysis examines a type of damage, low velocity indentation, and determines the effect on mechanical behavior. The scope of the analysis includes manufacturing sandwich composite structures, creating indentation in the composite, and testing the sandwich composite structure. The mechanical behavior of the composite …

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Enhanced Immunoprecipitation Techniques For The Identification Of Rna-Binding Protein Partners: Igf2bp1 Interactions In Mammary Epithelial Cells, Saja A. Fakhraldeen, Scott M. Berry, David J. Beebe, Avtar Roopra, Celia M. Bisbach, Vladimir S. Spiegelman, Natalie M. Niemi, Caroline M. Alexander Mar 2022

Enhanced Immunoprecipitation Techniques For The Identification Of Rna-Binding Protein Partners: Igf2bp1 Interactions In Mammary Epithelial Cells, Saja A. Fakhraldeen, Scott M. Berry, David J. Beebe, Avtar Roopra, Celia M. Bisbach, Vladimir S. Spiegelman, Natalie M. Niemi, Caroline M. Alexander

Mechanical Engineering Faculty Publications

RNA-binding proteins (RBPs) regulate the expression of large cohorts of RNA species to produce programmatic changes in cellular phenotypes. To describe the function of RBPs within a cell, it is key to identify their mRNA-binding partners. This is often done by crosslinking nucleic acids to RBPs, followed by chemical release of the nucleic acid fragments for analysis. However, this methodology is lengthy, which involves complex processing with attendant sample losses, thus large amounts of starting materials and prone to artifacts. To evaluate potential alternative technologies, we tested “exclusion-based” purification of immunoprecipitates (IFAST or SLIDE) and report here that these methods …

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Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz Mar 2022

Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz

Faculty Publications

Structural optimization is a methodology used to generate novel structures within a design space by finding a maximum or minimum point within a set of constraints. Topology optimization, as a subset of structural optimization, is often used as a means for light-weighting a structure while maintaining mechanical performance. This article presents the mathematical basis for topology optimization, focused primarily on the Bi-directional Evolutionary Structural Optimization (BESO) and Solid Isotropic Material with Penalization (SIMP) methodologies, then applying the SIMP methodology to a case study of additively manufactured lattice cells. Three lattice designs were used: the Diamond, I-WP, and Primitive cells. These …

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Vapor-Selective Active Membrane Energy Exchanger With Mechanical Ventilation And Indoor Air Recirculation, Andrew J. Fix, Bryan C. Pamintuan, James Braun, David M. Warsinger Mar 2022

Vapor-Selective Active Membrane Energy Exchanger With Mechanical Ventilation And Indoor Air Recirculation, Andrew J. Fix, Bryan C. Pamintuan, James Braun, David M. Warsinger

School of Mechanical Engineering Faculty Publications

It is widely known that increasing outdoor air ventilation rates in buildings can help improve indoor air quality and mitigate the spread of diseases. However, cooling and dehumidifying outdoor air requires significantly more energy than treating indoor recirculated air. Recent developments in water vapor-selective membranes, which use a vapor partial pressure gradient to remove water vapor from air, offer a unique opportunity to provide highly efficient dehumidification in HVAC systems that can justify high outdoor air ventilation rates without drastic increases in energy consumption. This work presents an analysis of a novel membrane HVAC system referred to as the Active …

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Pedagogical Approaches For Facilitating Engineering Leadership Development, Teresa J. Didiano, Annie E. Simpson, David J. Bayless Mar 2022

Pedagogical Approaches For Facilitating Engineering Leadership Development, Teresa J. Didiano, Annie E. Simpson, David J. Bayless

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This article describes transformative, impactful pedagogical practices that engage students in the process of leadership development. We share practical examples of instructional strategies and facilitation techniques from curricular and co-curricular initiatives.

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Thermo-Fluidic Transport Process In A Novel M-Shaped Cavity Packed With Non-Darcian Porous Medium And Hybrid Nanofluid: Application Of Artificial Neural Network (Ann), Dipak Kumar Mandal, Nirmalendu Biswas, Nirmal K. Manna, Dilip Kumar Gayen, Rama S. R. Gorla, Ali J. Chamkha Mar 2022

Thermo-Fluidic Transport Process In A Novel M-Shaped Cavity Packed With Non-Darcian Porous Medium And Hybrid Nanofluid: Application Of Artificial Neural Network (Ann), Dipak Kumar Mandal, Nirmalendu Biswas, Nirmal K. Manna, Dilip Kumar Gayen, Rama S. R. Gorla, Ali J. Chamkha

Faculty Publications

In this work, an attempt has been made to explore numerically the thermo-fluidic transport process in a novel M-shaped enclosure filled with permeable material along with Al2O3-Cu hybrid nanoparticles suspended in water under the influence of a horizontal magnetizing field. To exercise the influence of geometric parameters, a classical trapezoidal cavity is modified with an inverted triangle at the top to construct an M-shaped cavity. The cavity is heated isothermally from the bottom and cooled from the top, whereas the inclined sidewalls are insulated. The role of geometric parameters on the thermal performance is scrutinized thoroughly …

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Baja Sae Semi-Active Suspension, Philip Pang, Stassa Cappos, Harrison Hirsch, John Deboer Mar 2022

Baja Sae Semi-Active Suspension, Philip Pang, Stassa Cappos, Harrison Hirsch, John Deboer

Mechanical Engineering

This Final Design Review (FDR) Report outlines the senior design project of the Baja SAE Semi-Active Suspension group, which includes mechanical and electrical engineering students at California Polytechnic State University San Luis Obispo. This document compiles the Baja SAE Semi-Active Suspension senior project team’s research and development of a semi-active suspension system for the Cal Poly Racing Baja SAE racecar. The goal is to design a system that adjusts the damping constant of the racecar’s spring-damper suspension while the vehicle is being driven in order to improve vehicle dynamics and driver comfort. None of the semi-active dampers that exist on …

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Astm Test Fixture For Spinal Screws, Sarah K. Pickering, Matthew W. Rowen, Kaajal N. Khanna, Thomas A. Sunding Mar 2022

Astm Test Fixture For Spinal Screws, Sarah K. Pickering, Matthew W. Rowen, Kaajal N. Khanna, Thomas A. Sunding

Biomedical Engineering

This document is an overview report of the Cal Poly Senior Project ASTM Test Fixture for SeaSpine orthopedic bone screws. The main application of orthopedic screws is to fasten implants directly to the bone structure, enhancing structural integrity. Testing for breaking angle, insertion torque, removal torque, axial pullout strength, and self-tapping force as specified in the ASTM F543 Annexes provides the FDA with vital screw mechanics and ensures manufacturing uniformity. The test system is comprised of custom and off the shelf components allowing for interchangeability, in case of part failure, and a low overall cost. It is mechanically capable of …

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System Performance Model And Control System For A Small-Scale Horizontal Axis Wind Turbine, Niko Banks Mar 2022

System Performance Model And Control System For A Small-Scale Horizontal Axis Wind Turbine, Niko Banks

Master's Theses

Predicting the performance of wind turbines is a key part of the turbine design process and operation, as predictive models play a large role in determining potential power output and efficiency at different operating conditions to help maximize production. On small-scale wind turbines performance models become more complex, as the rotor aerodynamic performance depends not only on the tip speed ratio, but also on the flow Reynolds number. An accurate predictive model that includes this behavior on small-scale wind turbines can be used to find the optimal operating conditions for power output, and is also a critical component of the …

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Amplitude And Wavelength Scaling Of Sinusoidal Roughness Effects In Turbulent Channel Flow At Fixed ReΤ, Sparsh Ganju, Sean C. C. Bailey, Christoph Brehm Feb 2022

Amplitude And Wavelength Scaling Of Sinusoidal Roughness Effects In Turbulent Channel Flow At Fixed ReΤ, Sparsh Ganju, Sean C. C. Bailey, Christoph Brehm

Mechanical Engineering Faculty Publications

Direct numerical simulations are performed for incompressible, turbulent channel flow over a smooth wall and different sinusoidal wall roughness configurations at a constant Reτ = 720. Sinusoidal walls are used to study the effects of well-defined geometric features of roughness-amplitude, a, and wavelength, λ, on the flow. The flow in the near-wall region is strongly influenced by both a and λ. Establishing appropriate scaling laws will aid in understanding the effects of roughness and identifying the relevant physical mechanisms. Using inner variables and the roughness function to scale the flow quantities provides support for Townsend’s hypothesis, …

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A Continuum Damage Approach To Spallation And The Role Of Microinertia, S. B. Qamar, John A. Moore, Nathan R. Barton Feb 2022

A Continuum Damage Approach To Spallation And The Role Of Microinertia, S. B. Qamar, John A. Moore, Nathan R. Barton

Mechanical Engineering Faculty Research and Publications

Spall failure is of interest due to its prevalence in high strain rate problems in which the spallation is driven by the interaction of release waves. In this article, a porosity-based damage model that includes microinertial effects is used to examine spall failure. The model is successfully calibrated to plate impact-driven experiments and then used to evaluate experimental conditions producing more extreme strain rate conditions, such as those in laser-driven experiments. The incorporation of microinertia allows us to better understand the increase in apparent macroscopic spall strength seen at high strain rates. Correspondingly, we conclude that the incorporation of microinertial …

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Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi Feb 2022

Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi

Faculty Publications

Conventional microcarriers used for expansion of human mesenchymal stem cells (hMSCs) require detachment and separation of the cells from the carrier prior to use in clinical applications for regeneration of articular cartilage, and the carrier can cause undesirable phenotypic changes in the expanded cells. This work describes a novel approach to expand hMSCs on biomimetic carriers based on adult or fetal decellularized bovine articular cartilage that supports tissue regeneration without the need to detach the expanded cells from the carrier. In this approach, the fetal or adult bovine articular cartilage was minced, decellularized, freeze-dried, ground, and sieved to produce articular …

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Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi Feb 2022

Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi

Faculty Publications

Conventional microcarriers used for expansion of human mesenchymal stem cells (hMSCs) require detachment and separation of the cells from the carrier prior to use in clinical applications for regeneration of articular cartilage, and the carrier can cause undesirable phenotypic changes in the expanded cells. This work describes a novel approach to expand hMSCs on biomimetic carriers based on adult or fetal decellularized bovine articular cartilage that supports tissue regeneration without the need to detach the expanded cells from the carrier. In this approach, the fetal or adult bovine articular cartilage was minced, decellularized, freeze-dried, ground, and sieved to produce articular …

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Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci Feb 2022

Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci

Faculty Publications

This work presents the fourth-order comprehensive sensitivity analysis methodology for nonlinear systems (abbreviated as “4th-CASAM-N”) for exactly and efficiently computing the first-, second-, third-, and fourth-order functional derivatives (customarily called “sensitivities”) of physical system responses (i.e., “system performance parameters”) to the system’s (or model) parameters. The qualifier “comprehensive” indicates that the 4th-CASAM-N methodology enables the exact and efficient computation not only of response sensitivities with respect to the customary model parameters (including computational input data, correlations, initial and/or boundary conditions) but also with respect to imprecisely known material boundaries, caused by manufacturing tolerances, of the system under consideration. The 4th-CASAM-N …

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Comparative Study Of Decision Tree Models For Bearing Fault Detection And Classification, Armin Moghadam, Fatemeh Davoudi Kakhki Feb 2022

Comparative Study Of Decision Tree Models For Bearing Fault Detection And Classification, Armin Moghadam, Fatemeh Davoudi Kakhki

Faculty Research, Scholarly, and Creative Activity

Fault diagnosis of bearings is essential in reducing failures and improving functionality and reliability of rotating machines. As vibration signals are non-linear and non-stationary, extracting features for dimension reduction and efficient fault detection is challenging. This study aims at evaluating performance of decision tree-based machine learning models in detection and classification of bearing fault data. A machine learning approach combining the tree-based classifiers with de-rived statistical features is proposed for localized fault classification. Statistical features are extracted from normal and faulty vibration signals though time do-main analysis to develop tree-based models of AdaBoost (AD), classification and regression trees (CART), LogitBoost …

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Large Scale Dataset Of Real Space Electronic Charge Density Of Cubic Inorganic Materials From Density Functional Theory (Dft) Calculations, Fancy Qian Wang, Kamal Choudhary, Jianjun Hu, Ming Hu Feb 2022

Large Scale Dataset Of Real Space Electronic Charge Density Of Cubic Inorganic Materials From Density Functional Theory (Dft) Calculations, Fancy Qian Wang, Kamal Choudhary, Jianjun Hu, Ming Hu

Faculty Publications

Driven by the big data science, material informatics has attracted enormous research interests recently along with many recognized achievements. To acquire knowledge of materials by previous experience, both feature descriptors and databases are essential for training machine learning (ML) models with high accuracy. In this regard, the electronic charge density ρ(r), which in principle determines the properties of materials at their ground state, can be considered as one of the most appropriate descriptors. However, the systematic electronic charge density ρ(r) database of inorganic materials is still in its infancy due to the difficulties in …

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Auto-Ethnographic Reflections: Lessons From Leading A Stem Initiative For Girls In School While We Ourselves Were In School, Kayli Heather Battel, Kritin Mandala, Sreyoshi Bhaduri, Natalie Anna Foster, Lilianny Virguez, Lissa Erickson, Krishna Pakala Feb 2022

Auto-Ethnographic Reflections: Lessons From Leading A Stem Initiative For Girls In School While We Ourselves Were In School, Kayli Heather Battel, Kritin Mandala, Sreyoshi Bhaduri, Natalie Anna Foster, Lilianny Virguez, Lissa Erickson, Krishna Pakala

Mechanical and Biomedical Engineering Faculty Publications and Presentations

In this paper, we use an auto-ethnographic approach to describe first-hand the reflections and learnings from leading an organization to help school children, especially girls, familiarize themselves with STEM and Cyber Security. The primary authors and ethnographers are founders of STEM initiatives for young learners. The primary author is a recent high school graduate who has taken up an engineering field, and two other contributing authors are high-schoolers currently leading these initiatives. With help from the three engineering educators on our authorship team, we use our individual self-narratives to develop a set of recommendations for other young engineering educators across …

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Opportunities From Disruption: How Lifelong Learning Helped Create More Connected Classrooms, Krishna Pakala, Sreyoshi Bhaduri Feb 2022

Opportunities From Disruption: How Lifelong Learning Helped Create More Connected Classrooms, Krishna Pakala, Sreyoshi Bhaduri

Mechanical and Biomedical Engineering Faculty Publications and Presentations

The coronavirus pandemic has led to instructors worldwide seeking ways to engage students better through virtual platforms. As the world interacts online, more than ever before, this paper reflects on an educator’s experience with the virtual teaching and learning spaces pre and during the ongoing pandemic. Autoethnography is a research methodology that analyzes a phenomenon through the use of self-narratives, which would otherwise remain private or buried. This paper uses an autoethnographic approach to describe first-hand. the experiences and learnings of an educator at a Western US Public University. This paper describes how first as an international student, a first …

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Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu Feb 2022

Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu

Tanzania Journal of Engineering and Technology (TJET)

Gesture recognition is broadly utilized within the field of sensing. There are basically three gesture recognition methods based on computer vision, depth sensor and motion sensor. Motion sensor-based gesture recognition has few input data, fast speed, and direct access to three- dimensional information of the hand. The advantages of traditional motion sensor-based gesture recognition have gradually become a current research hotspot. The essence of traditional motion sensor-based gesture recognition is a pattern recognition problem, and its accuracy depends heavily on the feature dataset extracted from prior experience. Unlike traditional pattern recognition methods, deep learning can be used to a large …

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Economic Analysis Of Islanded Microgrid: A Case Study Of Kisiju Village - Coastal Region, Jackson Justo Feb 2022

Economic Analysis Of Islanded Microgrid: A Case Study Of Kisiju Village - Coastal Region, Jackson Justo

Tanzania Journal of Engineering and Technology (TJET)

The concept of Microgrid (MG) has gained significant attention of researchers and projects on the business side of electrical power generation and utilization, particularly in electrification of islanded areas such as villages. Most of these microgrids are powered by renewable energy resources (RERs) and they distribute power in low voltage distribution networks. Hence, these systems are faced with reliability problems due to the intermittency nature of RERs which affect the technical as well as the return on Investment of specific projects. In the latter context, reliability and economic analysis of the MG systems is an inevitable choice. This paper presents …

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Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John Feb 2022

Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John

Tanzania Journal of Engineering and Technology (TJET)

In portfolio optimization, the fundamental goal of an investor is to optimally allocate investments between different assets. Mean-variance optimization methods make unrealistic assumptions to solve the problem of optimal allocation. On the other hand, when realistic constraints like holding size and cardinality are introduced it leads to optimal asset allocation which differ from the mean variance optimization. The resulting optimization problem become quite complex as it exhibits multiple local extrema and discontinuities. Heuristic algorithms work well for the complex problem. Therefore, a heuristic algorithm is developed which is based on hill climbing complete (HC-C). It is utilized to solve the …

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Effect Of Processing Parameters And Build Orientation On Microstructure And Performance Of Aisi Stainless Steel 304l Made With Selective Laser Melting Under Different Strain Rates, Tan Pan, Xinchang Zhang, Aaron Flood, Sreekar Karnati, Wei Li, Joseph William Newkirk, Frank W. Liou Feb 2022

Effect Of Processing Parameters And Build Orientation On Microstructure And Performance Of Aisi Stainless Steel 304l Made With Selective Laser Melting Under Different Strain Rates, Tan Pan, Xinchang Zhang, Aaron Flood, Sreekar Karnati, Wei Li, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

Selective laser melting (SLM) process allows greater geometry flexibility; therefore, it has become more widespread in its deployment in the industry for fabricating metal alloys. However, a material characterization study is needed in order to understand better the correlation between the process, microstructure, and performance. In the current study, the raw SLM fabricated AISI stainless steel 304 L was fabricated with different processing parameters and build orientations (horizontal, inclined, and vertical). The tensile behavior was evaluated under different strain rates (0.0001/s, 0.001/s, 0.01/s, and 0.1/s) and then compared to commercial cold-rolled and annealed counterparts. Grain structures, tensile strength, elongation-to-failure, strain …

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State Of Industry 5.0—Analysis And Identification Of Current Research Trends, Aditya Akundi, Daniel Euresti, Sergio Luna, Wilma Ankobiah, Amit Lopes, Immanuel Edinbarough Feb 2022

State Of Industry 5.0—Analysis And Identification Of Current Research Trends, Aditya Akundi, Daniel Euresti, Sergio Luna, Wilma Ankobiah, Amit Lopes, Immanuel Edinbarough

Manufacturing & Industrial Engineering Faculty Publications

The term Industry 4.0, coined to be the fourth industrial revolution, refers to a higher level of automation for operational productivity and efficiency by connecting virtual and physical worlds in an industry. With Industry 4.0 being unable to address and meet increased drive of personalization, the term Industry 5.0 was coined for addressing personalized manufacturing and empowering humans in manufacturing processes. The onset of the term Industry 5.0 is observed to have various views of how it is defined and what constitutes the reconciliation between humans and machines. This serves as the motivation of this paper in identifying and analyzing …

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Open-Loop Control Of Electrostatic Levitation Actuators To Enhance The Travel-Range Of Optical Switches, Mohammad Mousavi, Mohammad Alzgool, Daniel Lopez, Shahrzad Towfighian Feb 2022

Open-Loop Control Of Electrostatic Levitation Actuators To Enhance The Travel-Range Of Optical Switches, Mohammad Mousavi, Mohammad Alzgool, Daniel Lopez, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

Command shaping is a driving technique for handling the large settling time of the high-Q-MEMS actuators. The strong nonlinearity due to the electrostatic actuation limits the linear operation range in cantilevered or torsional micro-mirrors where command shaping techniques can be applied for positioning. Experimental and simulation results of this research demonstrate the effectiveness of using electrostatic levitation to overcome the actuation nonlinearities and a significant increase in the operation range. The motivation for this research is that applying the nonlinear command shaping causes complexity in command manipulation and requires an accurate knowledge of the nonlinear terms involved in the system …

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Modification Of Superabsorbent Hydrogels For Industrial Wastewater Treatment, Md. Owaleur Rahman, Md. Abdul Halim, Anjan Deb, Shafi Ahmed, Md. Wasikur Rahman, N. C. Dafader, S. M. Nur Alam, Shahjalal Khandaker, Md. Jahangir Alam Feb 2022

Modification Of Superabsorbent Hydrogels For Industrial Wastewater Treatment, Md. Owaleur Rahman, Md. Abdul Halim, Anjan Deb, Shafi Ahmed, Md. Wasikur Rahman, N. C. Dafader, S. M. Nur Alam, Shahjalal Khandaker, Md. Jahangir Alam

Mechanical Engineering Faculty Publications

A breakthrough in superabsorbent hydrogel (SAH) preparation was studied in the current issue by blending potato starch and acrylic acid for wastewater treatment. Gamma irradiation source (60Co irradiation) was used to irradiate SAH from 1 to 10 kGy dose at room temperature (~27°C). The swelling ratio, water absorption, equilibrium water content, and gel fraction properties of the hydrogel were investigated. The as-prepared hydrogel treated with KOH (THG) showed excellent absorption capacity but less mechanical stability compared to untreated hydrogel (UHG). The gel fraction of treated SAH was slightly lower in methanol, but the utmost in water at 5 kGy infers …

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Six-Bar Linkage Models Of A Recumbent Tricycle Mechanism To Increase Power Throughput In Fes Cycling, Nicholas A. Lanese, David H. Myszka, Anthony L. Bazler, Andrew P. Murray Feb 2022

Six-Bar Linkage Models Of A Recumbent Tricycle Mechanism To Increase Power Throughput In Fes Cycling, Nicholas A. Lanese, David H. Myszka, Anthony L. Bazler, Andrew P. Murray

Mechanical and Aerospace Engineering Faculty Publications

This paper presents the kinematic and static analysis of two mechanisms to improve power throughput for persons with tetra- or paraplegia pedaling a performance tricycle via FES. FES, or functional electrical stimulation, activates muscles by passing small electrical currents through the muscle creating a contraction. The use of FES can build muscle in patients, relieve soreness, and promote cardiovascular health. Compared to an able-bodied rider, a cyclist stimulated via FES produces an order of magnitude less power creating some notable pedaling difficulties especially pertaining to inactive zones. An inactive zone occurs when the leg position is unable to produce enough …

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Strong Laser Polarization Control Of Coherent Phonon Excitation In Van Der Waals Material Fe3Gete2, Yu Gong, Ming Hu, Nico Harris, Zhonghua Yang, Ti Xie, Alem Teklu, Narayanan Kuthirummal, Jacob Koenemann, Xianghan Xu, Sang-Wook Cheong, Will Mcloud, Cheng Gong Feb 2022

Strong Laser Polarization Control Of Coherent Phonon Excitation In Van Der Waals Material Fe3Gete2, Yu Gong, Ming Hu, Nico Harris, Zhonghua Yang, Ti Xie, Alem Teklu, Narayanan Kuthirummal, Jacob Koenemann, Xianghan Xu, Sang-Wook Cheong, Will Mcloud, Cheng Gong

Faculty Publications

Optical manipulation of coherent phonon frequency in two-dimensional (2D) materials could advance the development of ultrafast phononics in atomic-thin platforms. However, conventional approaches for such control are limited to doping, strain, structural or thermal engineering. Here, we report the experimental observation of strong laser-polarization control of coherent phonon frequency through time-resolved pump-probe spectroscopic study of van der Waals (vdW) materials Fe3GeTe2. When the polarization of the pumping laser with tilted incidence is swept between in-plane and out-of-plane orientations, the frequencies of excited phonons can be monotonically tuned by as large as 3% (~100 GHz). Our first-principles …

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Per-Person And Whole-Building Voc Emission Factors In An Occupied School With Gas-Phase Air Cleaning., Brett W. Stinson, Aurélie Laguerre, Elliott T. Gall Feb 2022

Per-Person And Whole-Building Voc Emission Factors In An Occupied School With Gas-Phase Air Cleaning., Brett W. Stinson, Aurélie Laguerre, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Using real-time measurements of CO and volatile organic compounds (VOCs) in the air handler of an occupied middle school, we quantified source strengths for 249 VOCs and apportioned the source to the building, occupants and their activities, outdoor air, or recirculation air. For VOCs quantified in this study, there is a source to the outdoors of 8.6 ± 1.8 g/h in building exhaust air, of which 5.9 ± 1.7 g/h can be attributed to indoor sources (the building and occupants and their activities). The corresponding whole-building area emission factor from indoor sources is 1020 ± 300 μg/(m h), including reactive …

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A Tale Of Two Sides: Modeling Great Salt Lake Flows To Help Balance Current Ecosystem Influences, Eric Larsen Feb 2022

A Tale Of Two Sides: Modeling Great Salt Lake Flows To Help Balance Current Ecosystem Influences, Eric Larsen

Research on Capitol Hill

USU senior Eric, hailing from Spanish Fork, studies mechanical engineering and funded this project through an engineering student grant. While there are several sampling stations that measure the waterflow of the Great Salt Lake, there are gaps in the data they collect that limit our ability to predict how water moves between the north and south sides of the lake. Eric has been developing machine learning models that more accurately portray the flows. This has applications for both GSL ecological preservation and the brine shrimp and salt industries. Eric loved how hands-on this project was, seeing the phenomenon that his …

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Storage Minimization Of Marine Energy Grids Using Polyphase Power, Salman Husain, Gordon Parker, Wayne W. Weaver Feb 2022

Storage Minimization Of Marine Energy Grids Using Polyphase Power, Salman Husain, Gordon Parker, Wayne W. Weaver

Michigan Tech Publications, Part 1

Multiple wave energy converter (WEC) buoys can be used to establish a WEC array-powered microgrid collectively forming a Marine Energy Grid (MEG). An oceanic domain with gravity waves will have significant spatial variability in phase, causing the power produced by a WEC array to have high peak-to-average ratios. Minimizing these power fluctuations reduces the demand for large energy storage by WEC array-powered DC microgrids while also reducing losses in the undersea cable to the shore. Designs that reduce energy storage requirements are desirable to reduce deployment and maintenance costs. This work demonstrates that polyphase power in conjunction with an energy …

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