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2023

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Articles 5521 - 5550 of 9780

Full-Text Articles in Engineering

Science Club, Danielle Gibson, Krista Andersen Apr 2023

Science Club, Danielle Gibson, Krista Andersen

Honors Program: Expanded Learning Clubs

Honors After School program for elementary age children to engage with scientific principles. Students performed hands-on experiments to explore various STEM fields. Each weekly lesson consisted of a different concept to be learned or explored by early elementary aged students.


Earthquake Resistant Buildings, Admin Stem For Success Apr 2023

Earthquake Resistant Buildings, Admin Stem For Success

STEM for Success Showcase

Students learn about earthquakes and engineering by building a structure that can survive an earthquake.


Farmer's Tower, Admin Stem For Success Apr 2023

Farmer's Tower, Admin Stem For Success

STEM for Success Showcase

Students are challenged to help a famer build a tower to monitor their crops using only wood planks and pumpkins.


Balloon Tower Activity, Admin Stem For Success Apr 2023

Balloon Tower Activity, Admin Stem For Success

STEM for Success Showcase

This activity challenges students to build a safe and sound tower using only balloons and tape.


Load-Deformation Behavior Of Tension-Only X-Brace Roof Truss Diaphragms, Benjamin Johnson Meek Apr 2023

Load-Deformation Behavior Of Tension-Only X-Brace Roof Truss Diaphragms, Benjamin Johnson Meek

Theses and Dissertations

The alternative seismic design provisions for diaphragms provided in ASCE 7-22 Minimum design loads and associated criteria for buildings and other structures Section 12.10.3 account for both diaphragm ductility and displacement capacity, producing more accurate design forces and decreased detailing when compared to conventional seismic design methods. However, the diaphragm design force reduction factor has not yet been determined for tension-only roof truss diaphragms, a common system used in metal buildings. In this study, experimental tests of two cantilevered diaphragm subassembly specimens with tension-only rod bracing were conducted to determine the load-deformation behavior of the system. The first specimen used …


From Point Estimates To Predictive Distributions In Machine Learning Models - A Statistical Importance Sampling Framework, Giuseppina Carannante Apr 2023

From Point Estimates To Predictive Distributions In Machine Learning Models - A Statistical Importance Sampling Framework, Giuseppina Carannante

Theses and Dissertations

In this thesis, we leverage powerful statistical frameworks for optimal sequential estimation and tracking in non-linear and non-Gaussian dynamical models, which enjoy proven (asymptotic) optimality properties. Initially, we build upon our previous work, which employed first-order Taylor series approximation to propagate the first two predictive moments, to derive Bayesian encoder-decoder networks. This work introduced the notion of dense, pixel-level uncertainty map that is crucial in fields, such as autonomous vehicles and medical segmentation. We then extended the Bayesian framework to an ensembling scheme based on ensemble Kalman Filtering (EnKF). While EnKF represents the predictive distribution with an ensemble of draws, …


Pumpkin Tower Activity, Admin Stem For Success Apr 2023

Pumpkin Tower Activity, Admin Stem For Success

STEM for Success Showcase

In this activity, students are challenged to build a tower to help a farmer watch his crops using only pumpkins and wood planks. Attached is a lesson plan and a teacher reflection on the activity


Haptic Systems: Trends And Lessons Learned For Haptics In Spacesuits, Mohammad Amin Kuhail, Jose Berengueres, Fatma Taher, Mariam Alkuwaiti, Sana Z. Khan Apr 2023

Haptic Systems: Trends And Lessons Learned For Haptics In Spacesuits, Mohammad Amin Kuhail, Jose Berengueres, Fatma Taher, Mariam Alkuwaiti, Sana Z. Khan

All Works

Haptic technology uses forces, vibrations, and movements to simulate a sense of touch. In the context of spacesuits, proposals to use haptic systems are scant despite evidence of their efficacy in other domains. Existing review studies have sought to summarize existing haptic system applications. Despite their contributions to the body of knowledge, existing studies have not assessed the applicability of existing haptic systems in spacesuit design to meet contemporary challenges. This study asks, “What can we learn from existing haptic technologies to create spacesuits?”. As such, we examine academic and commercial haptic systems to address this issue and draw insights …


Reconfigurable Metatiles With Circular Maze-Like Space-Coiling-Based Acoustic Metastructure For Low-To-Mid Frequency Sound Attenuation, Sanjay Kumar, Heow Pueh Lee Apr 2023

Reconfigurable Metatiles With Circular Maze-Like Space-Coiling-Based Acoustic Metastructure For Low-To-Mid Frequency Sound Attenuation, Sanjay Kumar, Heow Pueh Lee

Durham School of Architectural Engineering and Construction: Faculty Publications

This study presents a compact, lightweight, and reconfigurable acoustic metatile for sound mitigation applications. The metatile prototype is designed based on a circular maze-like acoustic metastructure, which utilizes a space-coiling technique for enhanced acoustic performance in low-to-mid frequencies. The proposed labyrinthine acoustic metadisk structure comprises a central hollow front face sheet and two coiling-up backing cavities. Experimental results show that the metadisk has high absorption peaks of 0.81 and 0.75 at 574 and 1436 Hz, respectively, and exhibits high sound transmission loss (STL) values (≥25 dB) in separate wide frequency bands between 100–580 Hz and 820–1600 Hz. Based on the …


Mechanical Characterization Of Additively Manufactured Alloys Compared To Their Wrought Counterparts, Laith A. Alqawasmi Apr 2023

Mechanical Characterization Of Additively Manufactured Alloys Compared To Their Wrought Counterparts, Laith A. Alqawasmi

Mechanical Engineering ETDs

Additive manufacturing is a method of manufacturing based on building parts layer by layer, allowing for more control over shape of the product, therefore reducing machining costs, reducing material waste, faster production times and the ability to build complex engineering design that other manufacturing technologies won’t be able to produce. This research is on the tensile and indentation testing (following ASME standards) of 3D printed Ti-6Al-4V and Inconel 718 built by powder-based direct energy deposition technology. Ti-6Al-4V is an attractive material for the aerospace and aviation industry, and Inconel 718, a nickel-chromium based superalloy, is an attractive material for usage …


First Episodic Atmospheric Deposition Of Nutrients To Utah Lake: Statistical Analysis And Characterization, Cristian Alun Dorrett Apr 2023

First Episodic Atmospheric Deposition Of Nutrients To Utah Lake: Statistical Analysis And Characterization, Cristian Alun Dorrett

Theses and Dissertations

Atmospheric deposition (AD) is a significant but poorly understood source of nutrients to many aquatic systems around the world. Accurate characterization of the nutrient budgets of aquatic systems is critical to good management decisions, so a better understanding of AD-related nutrient loads is essential, especially for water bodies where nutrient loads from atmospheric deposition are significant. Due to its large surface area, proximity to Great Basin dust sources, high values of atmospheric particulates due to inversions, and the high phosphorus content of local soils, Utah Lake, in the semi-arid Utah Valley, USA, experiences significant phosphorus loading from AD. The lake …


Simulations Of Electrode Heterogeneity And Design For Lithium-Ion Batteries, Amir Sina Hamedi Apr 2023

Simulations Of Electrode Heterogeneity And Design For Lithium-Ion Batteries, Amir Sina Hamedi

Theses and Dissertations

This work develops three models for simulation of the high-current operation of Li-ion batteries. Simulation as a tool can provide understanding beyond what experiments can offer. Different types of electrodes such as graphite, silicon, and NMC are modeled to study cell performance and aging under aggressive operating conditions. The first part of this work focuses on the effect of electrode microscale lateral heterogeneity on the degradation of conventional Li-ion batteries, especially for fast-charge applications. The non-uniform pore distribution leads to the nonuniform current density and state of charge (SoC), which can finally result in non-uniform Li plating and aging. The …


Stretchable Sensors For Soft Robotic Grippers In Edge-Intelligent Iot Applications, Prosenjit Kumar Ghosh, Prabha Sundaravadivel Apr 2023

Stretchable Sensors For Soft Robotic Grippers In Edge-Intelligent Iot Applications, Prosenjit Kumar Ghosh, Prabha Sundaravadivel

Electrical Engineering Faculty Publications and Presentations

The rapid development of electronic material and sensing technology has enabled research to be conducted on liquid metal-based soft sensors. The application of soft sensors is widespread and has many applications in soft robotics, smart prosthetics, and human-machine interfaces, where these sensors can be integrated for precise and sensitive monitoring. Soft sensors can be easily integrated for soft robotic applications, where traditional sensors are incompatible with robotic applications as these types of sensors show large deformation and very flexible. These liquid-metal-based sensors have been widely used for biomedical, agricultural and underwater applications. In this research, we have designed and fabricated …


Designing An Equity-Centered Framework And Crosswalk For Integrated Elementary Computer Science Curriculum And Instruction, Carla Strickland, Andrea Ramírez-Salgado, Lauren Weisberg, Latoya Chandler, Jeanne Di Domenico, Elizabeth M. Lehman, Maya Israel Apr 2023

Designing An Equity-Centered Framework And Crosswalk For Integrated Elementary Computer Science Curriculum And Instruction, Carla Strickland, Andrea Ramírez-Salgado, Lauren Weisberg, Latoya Chandler, Jeanne Di Domenico, Elizabeth M. Lehman, Maya Israel

Journal of Computer Science Integration

As computer science (CS) education becomes more prevalent in K-12 instruction, it is critical for educators, researchers, and curriculum developers to identify culturally responsive and pedagogically inclusive approaches that can increase participation, access, and feelings of belonging for students from historically marginalized communities. In response, we developed an equity-centered curricular framework and illustrative crosswalk that synchronizes three distinct pedagogical approaches: culturally responsive pedagogy (CRP), Universal Design for Learning (UDL), and project-based learning (PBL). We describe the framework’s theoretical underpinnings and explain how this framework informed the development of an integrated elementary science+CS curricular unit and provide examples of its implementation. …


Modifying Barium Hexaferrite Magnets By Adding Sol-Gel Synthesized Cobalt Ferrite Phase, Thanida Charoensuk, Wannisa Thongsamrit, Anuchit Hunyek, Komkrich Chokprasombat, Pongsakorn Jantaratana, Chitnarong Sirisathitkul Apr 2023

Modifying Barium Hexaferrite Magnets By Adding Sol-Gel Synthesized Cobalt Ferrite Phase, Thanida Charoensuk, Wannisa Thongsamrit, Anuchit Hunyek, Komkrich Chokprasombat, Pongsakorn Jantaratana, Chitnarong Sirisathitkul

Karbala International Journal of Modern Science

Combining various types of ferrites brings about magnetic properties desirable for different applications. This study aims to modify barium hexaferrite (BaFe12O19) by physically mixing it with cobalt ferrite (CoFe2O4). BaFe12O19/CoFe2O4 magnets were produced by ball-milling and pressing sol-gel-derived ferrite powders. The ferrite composites showed variations in magnetic properties from BaFe12O19 magnets with a saturation magnetization of 69.46 emu/g and a maximum energy product of 0.4529 MGOe. For the BaFe12O19:CoFe2O4 weight ratio of 4:1, both satura-tion …


Building Rotary Fans, Admin Stem For Success, Natalie Wilson Apr 2023

Building Rotary Fans, Admin Stem For Success, Natalie Wilson

STEM for Success Showcase

Students are challenged to build a working rotary fan


Paper Chain Challenge, Admin Stem For Success, Natalie Wilson Apr 2023

Paper Chain Challenge, Admin Stem For Success, Natalie Wilson

STEM for Success Showcase

Activity Plan and teacher reflection on an activity where students work to creatively design the longest possible chain with limited materials


Bridge Building, Admin Stem For Success Apr 2023

Bridge Building, Admin Stem For Success

STEM for Success Showcase

Students learn about different bridge styles and designs in this activity that challenges them to build their own successful bridge.


Lock Box Challenge, Admin Stem For Success, Natalie Wilson Apr 2023

Lock Box Challenge, Admin Stem For Success, Natalie Wilson

STEM for Success Showcase

Students are challenged to make a lock box


Analysis Of Shielding Effectiveness Against Electromagnetic Interference (Emi) For Metal-Coated Polymeric Materials, Javad Baqersad, Seyed Jamaleddin Mostafavi Yazdi, Andrej Lisitski, Seongchan Pack, Huseyin R. Hiziroglu Apr 2023

Analysis Of Shielding Effectiveness Against Electromagnetic Interference (Emi) For Metal-Coated Polymeric Materials, Javad Baqersad, Seyed Jamaleddin Mostafavi Yazdi, Andrej Lisitski, Seongchan Pack, Huseyin R. Hiziroglu

Mechanical Engineering Publications

Lightweight materials, such as polymers and composites, are increasingly used in the automotive and aerospace industries. Recently, there has been an increase in the use of these materials, especially in electric vehicles. However, these materials cannot shield sensitive electronics from electromagnetic interference (EMI). The current work investigates the EMI performance of these lightweight materials using an experimental setup based on the ASTM D4935-99 standard and EMI simulation using the ANSYS HFSS. This work studies how metal coating from zinc and aluminum bronze can improve the shielding performance of polymer-based materials, such as polyphenylene sulfide (PPS), polyetheretherketone (PEEK), and polyphthalamide (PPA). …


Marble Run Maze Challenge, Admin Stem For Success Apr 2023

Marble Run Maze Challenge, Admin Stem For Success

STEM for Success Showcase

Students are asked to use provided materials to design and build a successful marble run. Attached is the activity worksheet for students and the teacher reflection on the activity.


Rubber Band Car Activity, Admin Stem For Success, Natalie Wilson Apr 2023

Rubber Band Car Activity, Admin Stem For Success, Natalie Wilson

STEM for Success Showcase

Student learn about forces and engineering by designing a car powered by rubber bands


Windmill Building Activity, Admin Stem For Success, Natalie Wilson Apr 2023

Windmill Building Activity, Admin Stem For Success, Natalie Wilson

STEM for Success Showcase

Students are challenged to build a windmill that can lift weight


To Study Heart Rate Dynamics Of Preterm Infants Using Lstm Based Deep Learning Model, Soniya Poudel Chhetri Apr 2023

To Study Heart Rate Dynamics Of Preterm Infants Using Lstm Based Deep Learning Model, Soniya Poudel Chhetri

Electrical Engineering Theses

Babies born prematurely are more likely to experience serious medical problems called Bradycardia, where their heart rate drops below 100 beats per minute(bpm). Bradycardia can decrease cerebral blood velocities by 10-50% from their normal level [6], potentially harming the infant's developing brain and other vital organs. Healthcare professionals working in Neonatal Intensive Care Units (NICUs) face challenges evaluating the likelihood of these events occurring in preterm babies based on their physiological signals. Forecasting and tracking bradycardia events before time will help save thousands of preterm infants from losing their lives. While time series analysis of heart rate data is one …


Proposed Mitigation Framework For The Internet Of Insecure Things, Mahmoud M. Elgindy, Sally M. Elghamrawy, Ali I. El-Desouky Apr 2023

Proposed Mitigation Framework For The Internet Of Insecure Things, Mahmoud M. Elgindy, Sally M. Elghamrawy, Ali I. El-Desouky

Mansoura Engineering Journal

Intrusion detection systems IDS are increasingly utilizing machine learning methods. IDSs are important tools for ensuring the security of network data and resources. The Internet of Things (IoT) is an expanding network of intelligent machines and sensors. However, they are vulnerable to attackers because of the ubiquitous and extensive IoT networks. Datasets from intrusion detection systems (IDS) have been analyzed deep learning methods such as Bidirectional long-short term memory (BiLSTM). This research presents an BiLSTM intrusion detection framework with Principal Component Analysis PCA (PCA-LSTM-IDS). The PCA-LSTM-IDS is comprised of two layers: extracting layer which using PCA, and the anomaly BiLSTM …


Claw Hand Activity, Admin Stem For Success, Natalie Wilson Apr 2023

Claw Hand Activity, Admin Stem For Success, Natalie Wilson

STEM for Success Showcase

Activity plan where students practice coding principles by programming the actions of a claw hand


Balloon Boat Races, Admin Stem For Success, Natalie Wilson Apr 2023

Balloon Boat Races, Admin Stem For Success, Natalie Wilson

STEM for Success Showcase

Students build balloon boats to learn buoyancy and practice engineering design skills.


A Threshold Helium Leakage Detection Switch With Ultra Low Power Operation, Sulaiman Mohaidat, Fadi M. Alsaleem Apr 2023

A Threshold Helium Leakage Detection Switch With Ultra Low Power Operation, Sulaiman Mohaidat, Fadi M. Alsaleem

Department of Mechanical and Materials Engineering: Faculty Publications

Detecting helium leakage is important in many applications, such as in dry cask nuclear waste storage systems. This work develops a helium detection system based on the relative permittivity (dielectric constant) difference between air and helium. This difference changes the status of an electrostatic microelectromechanical system (MEMS) switch. The switch is a capacitive-based device and requires a very negligible amount of power. Exciting the switch’s electrical resonance enhances the MEMS switch sensitivity to detect low helium concentration. This work simulates two different MEMS switch configurations: a cantilever-based MEMS modeled as a single-degreefreedom model and a clamped-clamped beam MEMS molded using …


Building Structures, Admin Stem For Success Apr 2023

Building Structures, Admin Stem For Success

STEM for Success Showcase

This activity challenges students to build a safe and sound structure using only candy and toothpicks.


Dash And Dot Robots, Admin Stem For Success, Natalie Wilson Apr 2023

Dash And Dot Robots, Admin Stem For Success, Natalie Wilson

STEM for Success Showcase

Activity plan using robots to teach students engineering and technology