Mechanical Engineering Commons^™

Electromechanics Modelling Of The Effects Of Myocardial Infarction On Left Ventricular Remodelling, Chin Neng Leong

Student Works (2020-2029)

Myocardial infarction (MI) is one of the diseases with the highest mortality rate. Following MI, myocardium experiences abrupt changes in its loading condition due to the presence of infarct. In response to such changes, myocytes undergo adaptations to maintain homeostasis. However, maladaptation can happen and lead to remodelling, in which the left ventricle (LV) gradually loses its function and eventually turns into heart failure. Nevertheless, the mechanisms underlying LV remodelling are still poorly understood. In this study, a generic LV model was developed, incorporating realistic fibre orientation and excitable contracting myocardium. It was demonstrated that the developed model is capable …

Kinematic Analysis Of Forehand Drop Shot And Long Shot Services In Table Tennis, Ibrahim Norzuria

Student Works (2020-2029)

Table tennis is one of the most widely played sports in the world. A frequent hand movement is compulsory to execute stroke than other limbs, especially the projection of racket and ball speeds,which can help to improve players’ performance. Until now, research on table tennis serving is limited. Service was assumed important in table tennis because the effective serve may allow the serving player to have advantage and control over the game. The 3D dynamic analysis is the appropriate method to analyze a sport activity such as table tennis. Therefore, the aim of research was to determine the kinematic involved …

Dual-Axis Solar Tracker, Bryan Kennedy

All Undergraduate Projects

Renewable energies, and fuels that are not fossil fuel-based, are one of the prolific topics of debate in modern society. With climate change now becoming a primary focus for scientists and innovators of today, one of the areas for the largest amount of potential and growth is that of the capturing and utilization of Solar Energy. This method involves using a mechanical system to track the progression of the sun as it traverses the sky throughout the day. A dual-axis solar tracker such as the one designed and built for this project, can follow the sun both azimuthally and in …

Analyzing Concrete Beam Design: Verifying Predictions In T&Ee Classrooms, Andrew J. Hughes, Chris Merrill

Educational Leadership & Technology Faculty Publications

Design is often accepted as a fundamental aspect of engineering (Dym, et al., 2005). The design process is frequently portrayed as a set of steps. However, the design process is more complex than just a set of steps in a relatively fixed process. The complex nature of design, design thinking, questioning, and decision-making is exactly what technology and engineering classrooms are well suited to address. When addressing the question—“Why is technology and engineering education (T&EE) so important?”—the authors believe T&EE’s importance relates to our discipline’s ability to solve complex problems by balancing theory and practice in engaging hands-on learning scenarios …

Adjustable Short Throw Shifter (Asts), Joshua Franklin

All Undergraduate Projects

Every manual transmission vehicle has a shift lever for changing gears. The problem is that the shifting linkage is setup up for one kind of driving. Numerous vehicles have multiple settings for the suspension to adapt to varying driving scenarios (i.e. cruising, sport, track). No vehicle currently has an adjustable short throw shifter (ASTS) that can accommodate drag racing, drifting, sports car racing, rallying, off-roading, or casual driving. The design of the ASTS solves this problem by moving the central axis of rotation of the shifter up two inches, permitting the adjustment of the shifting throw between 20 and 40%. …

Hierarchical Mechanisms Of Lateral Interactions In High- Performance Fibers, Taylor A, Stockdale, Daniel P. Cole, Jeffrey M. Staniszewski, Michael R. Roenbeck, Dimitry Papkov, Steve R. Lustig, Youris A. Dzenis, Kenneth E. Strawhecker

Department of Mechanical and Materials Engineering: Faculty Publications

The processing conditions used in the production of advanced polymer fibers facilitate the formation of an oriented fibrillar network that consists of structures spanning multiple length scales. The irregular nature of fiber tensile fracture surfaces suggests that their structural integrity is defined by the degree of lateral (interfacial) interactions that exist within the fiber microstructure. To date, experimental studies have quantified interfacial adhesion between nanoscale fibrils measuring 10−50 nm in width, and the global fracture energy through applying peel loads to fiber halves. However, a more in-depth evaluation of tensile fracture indicates that fiber failure typically occurs at an intermediate …

Cardiorespiratory Fitness, Balance And Walking Improvements In An Adolescent With Cerebral Palsy (Gmfcs Ii) And Autism After Motor-Assisted Elliptical Training, Guilherme Manna Cesar, Thad W. Buster, Judith M. Burnfield

Department of Mechanical and Materials Engineering: Faculty Publications

Purpose: To quantify the impact of motor-assisted elliptical (ICARE) training on cardiorespiratory fitness, balance and walking function of an adolescent with walking limitations due to cerebral palsy.

Materials and methods: A thirteen-year-old boy with hemiplegic cerebral palsy (Gross Motor Function Classification System II) and autism participated. Peak oxygen consumption (peak VO₂, primary outcome measure), oxygen cost of walking, Pediatric Balance Scale (PBS), modified Timed Up and Go (mTUG), 2-Minute Walk Test (2MWT), and gait characteristics (speed, cadence, step length, single support time) were assessed prior to and after completion of 24 sessions of moderate- to vigorous- intensity ICARE …

Three-Dimensional Characterization Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer In Patients Following Lumbar Puncture, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Purpose: To develop and test an innovative semi-automatic method for quantifying the three-dimensional morphology of the peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer, with application to lumbar puncture (LP) patients. Methods: Nineteen patients undergoing LP were recruited. The optic nerve head images of both eyes were acquired in 12 radial directions using optical coherence tomography (OCT) before and after LP. For each OCT image, the ppRPE/BM layer was automatically segmented with manual corrections by independent graders when necessary. The linear regression model of the ppRPE/BM layer was fitted using the least squares approach, and the ppRPE/BM layer angle was measured …

Roboticdeviceswithonboard Control And Related Systems And Devices, Shane Michael Farritor, Erik Mumm, Philip Chu, Nishant Kumar, Jason Dumpert, Yutaka Tsutano

Department of Mechanical and Materials Engineering: Faculty Publications

The embodiments disclosed herein relate to various medical device components, including components that can be incorporated into robotic and/or in vivo medical devices. Certain embodiments include various modular medical devices for in vivo medical procedures.

Role Of Interfacial Transition Zones In The Fracture Of Cu/V Nanolamellar Multilayers, Siyuan Wei, Shijian Zheng, Lifeng Zhang, Yue Liu, Jian Wang, Xianping Wang, Jiangwei Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Plastic deformation and fracture behavior of Cu/V nanoscale metallic multilayers (NMMs) were systematically investigated through in situ transmission electron microscopy testing. Two different types of interfaces: sharp interfaces and interfacial transition zones (ITZs), formed in the as-fabricated Cu/V NMMs. Upon deformation, sharp interfaces and ITZs exert distinct influences on the fracture behavior of Cu/V NMMs. Sharp interfaces can impede the crack propagation by deflecting the crack propagation and blunting the crack tip, while the ITZs can induce microcracks and facilitate the fracture process. These findings shed light on the important roles of interface structures in the deformation of a broad …

R/C Mini Baja Car: Drive Train And Steering, Carlton R. Mcdonald

All Undergraduate Projects

The purpose of the Baja R/C Car is to compete in the ASME eFX competition in a series of events to prove the functionality of the vehicle. This series of events includes the Slalom, Drag, and Baja race, The Slalom is a test in the steering capability of the vehicle, the Drag is a test in the acceleration of the vehicle in a straight line, and the Baja puts all factors together in a race to test every component of the vehicle. This project is about building an R/C car that not only functions, but also has maximum performance capabilities …

Mechanical Footstep Power Generator, Mohammed Saleh Aljohani, Faisal Alonazi

All Undergraduate Projects

Mechanical Footstep Power generator

By Author: Mohammed Aljohani

Abstract

Modern technology is focusing on newer and better sources of energy. Among the important areas are power generation methods since electricity has become part of our lives. Various researchers have conducted surveys to find out the feasibility of converting renewable kinetic energy into electricity. Some of the works done in the past emphasized the selection of suitable materials and power generation systems designs that appear complicated and expensive. To ensure there is cost efficiency and energy efficiency better power generation systems need to be embraced.

The footstep power generator is a …

Low- And High-Drag Intermittencies In Turbulent Channel Flows, Rishav Agrawal, Henry C.-H. Ng, Ethan A. Davis, Jae Sung Park, Michael D. Graham, David J.C. Dennis, Robert J. Poole

Department of Mechanical and Materials Engineering: Faculty Publications

Recent direct numerical simulations (DNS) and experiments in turbulent channel flow have found intermittent low- and high-drag events in Newtonian fluid flows, at Reτ = uτh/ν between 70 and 100, where uτ, h and ν are the friction velocity, channel half-height and kinematic viscosity, respectively. These intervals of low-drag and high-drag have been termed “hibernating” and “hyperactive”, respectively, and in this paper, a further investigation of these intermittent events is conducted using experimental and numerical techniques. For experiments, simultaneous measurements of wall shear stress and velocity are carried out in a channel flow facility using hot-film anemometry (HFA) and laser …

A Numerical Simulation On The Airfoil S833 Equipped With Flapping Trailing Edge Fringes, H. Yu, Zifeng Yang

Mechanical and Materials Engineering Faculty Publications

Design optimization has been increasingly investigated for an airfoil, aiming to reduce the vorticity in the wake and increase the aerodynamic performance. In the current work, a two-dimensional (2D) S833 airfoil equipped with a flapping fringe at the trailing edge has been studied using computational fluid dynamics (CFD) simulations. The objective is to investigate the influence of the length (Lf) and flapping frequency (f) of the fringe on shedding vortices from the airfoil and the drag and lift coefficients. The validation of the current numerical approach for both static and dynamic motions of the airfoil was conducted. First, four different …

Multi-Well Plate Channel Device With Reversible Seals, Haipeng Zhang, Timothy Wei, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Atherosclerosis is a cardiovascular disease which causes over 26,000 yearly deaths in the United States. This disease involves accumulation of substances in arterial walls (or plaques) that occurs frequently to arterial regions experiencing low shear stress, such as bends and bifurcations. A possible reason of plaque growth in arterial walls is the change of endothelial cell (EC)’s shape, which is related to fluid shear stresses tangentially acting on intimal layer (the EC surface) of the arterial wall. Lambert et al. studied the relationship between EC shape and shear stress (Lambert et al., 2019) using a BioFlux system (Fluxion Bioscienes) and …

Universal Mechanical Exfoliation Of Large-Area 2d Crystals, Yuan Huang, Yu-Hao Pan, Rong Yang, Li-Hong Bao, Lei Meng, Hai-Lan Luo, Yong-Qing Cai, Guo-Dong Liu, Wen-Juan Zhao, Zhang Zhou, Liang-Mei Wu, Zhi-Li- Zhu, Ming Huang, Li-Wei Liu, Lei Liu, Peng Cheng, Ke-Hui Wu, Shi-Bing Tian, Chang-Zhi Gu, You-Guo Shi, Yan-Feng Guo, Zhi Gang Cheng, Jiang-Ping Hu, Lin Zhao, Guan-Hua Yang, Eli Sutter, Peter Sutter, Ye-Liang Wang, Wei Ji, Xing-Jiang Zhou, Hong-Jun Gao

Department of Mechanical and Materials Engineering: Faculty Publications

Two-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measure- ments of electron microscopy, photo spectroscopies and electrical transport. Large sus- pended …

Benign Ferroelastic Twin Boundaries In Halide Perovskites For Charge Carrier Transport And Recombination, Xun Xiao, Wenhao Li, Yanjun Fang, Ye Liu, Yuchuan Shao, Shuang Yang, Jingjing Zhao, Xuezeng Dai, Rashid Zia, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

Grain boundaries have been established to impact charge transport, recombination and thus the power conversion efficiency of metal halide perovskite thin film solar cells. As a special category of grain boundaries, ferroelastic twin boundaries have been recently discovered to exist in both CH3NH3PbI3 thin films and single crystals. However, their impact on the carrier transport and recombination in perovskites remains unexplored. Here, using the scanning photocurrent microscopy, we find that twin boundaries have negligible influence on the carrier transport across them. Photoluminescence (PL) imaging and the spatial-resolved PL intensity and lifetime scanning confirm the electronically benign nature of the twin …

Variations In Plantar Pressure Variables Across Elliptical Trainers In Older Adults, Judith M. Burnfield, Guilherme Manna Cesar, Thad W. Buster

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Ellipticals are used to address walking and cardiorespiratory training goals of older adults, some of whom are at risk for foot injuries. Variations in joint kinematics and muscle demands when using different ellipticals could lead to plantar pressure differences. This study explored plantar pressure variables during gait and use of four ellipticals.

Methods: Plantar pressures were recorded while 10 adults [68.1 (4.5) years] walked and used the True, Octane, Life Fitness, and SportsArt ellipticals. Repeated-measures ANOVAs (5 × 1) identified forefoot and heel differences across conditions.

Findings: Maximum forefoot forces and peak pressures were significantly lower than walking for …

การพัฒนาระบบติดตามสถานะรถยนต์สำหรับธุรกิจแบ่งปันรถยนต์โดยใช้ช่อง Obd-Ii, สรวิชญ์ สาครินทร์

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในช่วงไม่กี่ปีที่ผ่านมานี้ ธุรกิจแบ่งปันรถเช่าทั่วโลกเติบโตขึ้นอย่างมาก แต่การเช่ารถยนต์นั้นยังมีปัญหาอยู่สองข้อคือความไม่สะดวกต่อการทำสัญญาเช่ารถยนต์และการที่ไม่สามารถติดตามสถานะของรถยนต์ได้ เพื่อที่จะติดตามสถานะของถยนต์ เราต้องการระบบที่สามารถดึงข้อมูลดิบจากรถยนต์ส่งขึ้นสู่คลาวเซิฟเวอร์ในเวลาจริง ในช่วงเวลาเดียวกัน เทคโนโลยีอินเทอร์เน็ตทุกสรรพสิ่งได้ถูกนำไปใช้ในหลายๆอุตสาหกรรมเพื่อเพิ่มศักยภาพในการทำงาน เช่นอุตสาหกรรมการแพทย์ การเกษตร และการขนส่งอัจฉริยะ ดังนั้นธุรกิจแบ่งปันรถเช่านั้นจึงยังมีช่องว่างสำหรับการพัฒนาเพิ่มเติมด้วยเทคโนโลยีนี้เช่นกัน งานวิจัยนี้ได้ทำการพัฒนาอุปกรณ์สำหรับเชื่อมต่อภายในรถยนต์เรียกว่ากล่องโคบอกซ์ อุปกรณ์สามารถดึงข้อมูลที่ต้องการจากรถยนต์และสั่งล้อคหรือปลดล้อคได้ด้วยช่องโอบีดีทู อุปกรณ์สามารถรับสัญญาณตำแหน่งจีพีเอสและส่งข้อมูลที่ต้องการสู่คลาวไฟร์เบสเซิฟเวอร์ได้บนเวลาจริง อย่างไรก็ตาม ระบบติดตามสถานะของรถยนต์นี้สามารถทำงานได้ดีในรถยนต์ Toyota Altis 2016 เท่านั้น ผู้วิจัยจึงมีแผนในการพัฒนาระบบติดตามเพื่อรองรับกับรถยนต์รุ่นต่างๆต่อไปในอนาคต

Ultrahigh Strength And Plasticity In Laser Rapid Solidified Al–Si Nanoscale Eutectics, Huai-Hsun Lien, Jyoti Mazumder, Jian Wang, Amit Misra

Department of Mechanical and Materials Engineering: Faculty Publications

As-cast Al–20wt.% Si alloys were processed via laser rapid solidification (LRS) techniques to create eutectic microstructures with nanoscale interconnected, nanotwinned Si fibers. LRS morphologies exhibit higher flow stress, exceeding 800 MPa and uniform plastic deformation above 20% compared to as-cast alloy that fractures at strains below 8% at flow strength of approximately 200 MPa. The strengthening mechanisms of LRS morphologies are interpreted in terms of the interfacial constraints: increase in yield strength as well as strain hardening rate due to nanoscale confined slip in fibrous Al–Si eutectic, and load transfer and eventual plasticity in the nanoscale Si fibers.

Leidenfrost Droplet Microfluidics, Sidy Ndao, George Gogos, Dennis Alexander, Troy Anderson, Craig Zuhlke

Department of Mechanical and Materials Engineering: Faculty Publications

Systems and methods are described for propelling a liquid droplet in a Leidenforst state. A microfluidic device embodiment includes, but is not limited to, a solid structure having a patterned surface, the patterned surface including at least a first patterned region having a first Leidenfrost temperature with respect to a fluid, the first patterned region adjacent to the second patterned region, the first patterned region defining a path over which a droplet of the fluid is configured to travel in a Leidenfrost state.

Iron Pyrite Nanocrystals, Jinsong Huang, Baodong Mao, Christopher L. Exstrom

Department of Mechanical and Materials Engineering: Faculty Publications

An apparatus includes a nanocrystal. The nanocrystal includes a core including FeS2; and a coating including a ligand component capable of chemically interacting with both an iron atom and a sulfur atom on a surface of the core.

Colocalized Sensing And Intelligent Computing In Micro-Sensors, Mohammad H. Hasan, Ali Al-Ramini, Eihab Abdel-Rahman, Roozbeh Jafari, Fadi Alsaleem

Department of Mechanical and Materials Engineering: Faculty Publications

This work presents an approach to delay-based reservoir computing (RC) at the sensor level without input modulation. It employs a time-multiplexed bias to maintain transience while utilizing either an electrical signal or an environmental signal (such as acceleration) as an unmodulated input signal. The proposed approach enables RC carried out by sufficiently nonlinear sensory elements, as we demonstrate using a single electrostatically actuated microelectromechanical system (MEMS) device. The MEMS sensor can perform colocalized sensing and computing with fewer electronics than traditional RC elements at the RC input (such as analog- to-digital and digital-to-analog converters). The performance of the MEMS RC …

Microstructural Evolution Of Nanotwinned Al-Zr Alloy With Significant 9r Phase, N.A. Richter, Y.F. Zhang, D. Y. Xie, R. Su, Q. Li, S. Xue, T. Niu, J. Wang, H. Wang, Xinghang Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

Aluminum (Al) alloys have a multitude of applications, notably in the automotive, aerospace and coating industries, yet they exhibit significantly lower mechanical strength than conventional steels. Nanotwins drastically improve mechanical strength while retaining ductility. However, the high SFE of Al largely prevents twinning. Here, we synthesize Al-Zr alloy films containing an abundance of incoherent twin boundaries and 9R phases. These alloys exhibit an extended solid solubility of Zr, retaining a columnar nanotwinned structure across all compositions. These films reach a hardness up to 4.2 GPa with 10 at% Zr and demonstrate the capacity for producing strong Al alloys with nanotwins.

Atv Dynamics And Pediatric Rider Safety, James T. Auxier Ii

Theses and Dissertations--Biomedical Engineering

It has been observed through numerous academic and governmental agency studies that pediatric all-terrain vehicle ridership carries significant risk of injury and death. While no doubt valuable to safety, the post-hoc approach employed in these studies does little to explain the why and how behind the risk factors. Furthermore, there has been no prolonged, widespread, organized, and concerted effort to reconstruct and catalog the details and causes of the large (20,000+) number of ATV-related injuries that occur each year as has been done for road-based motor vehicle accidents. This dissertation takes the opposite approach from a meta-analysis and instead examines …

Influence Of Size Effects On Surface Generation During Finish Machining And Surface Integrity In Ti-6al-4v, Ian S. Brown

Theses and Dissertations--Mechanical and Aerospace Engineering

Finish machining is an essential manufacturing process that is used to enhance the mechanical characteristics of critical components. The deformation that occurs at the tool and workpiece interface in finish machining significantly affects a host of component properties, commonly referred to as “surface integrity” properties. Surface roughness is a machining deformation-affected characteristic that is of high relevance in contemporary manufacturing. However, over recent decades it has been made clear that the material properties of the deformed surface layers are relevant to component performance as well. Predicting the overall surface quality of a machined component is of great relevance to the …

Multiscale Modeling Of Carbon Fibers/Graphene Nanoplatelets/Epoxy Hybrid Composites For Aerospace Applications, Hashim Al Mahmud

Dissertations, Master's Theses and Master's Reports

Significant research effort has been dedicated for decades to improve the mechanical properties of aerospace polymer-based composite materials. Lightweight epoxy-based composite materials have increasingly replaced the comparatively heavy and expensive metal alloys used in aeronautical and aerospace structural components. In particular, carbon fibers (CF)/graphene nanoplatelets (GNP)/epoxy hybrid composites can be used for this purpose owing to their high specific stiffness and strength. Therefore, this work has been completed to design, predict, and optimize the effective mechanical properties of CF/GNP/epoxy composite materials at different length scales using a multiscale modeling approach. The work-flow of modeling involves a first step of using …

Increasing Access To Pv Technology Through Sustainable Racking: A Review Of Existing Literature And Ground Mounted Fixed Tilt Designs, And What Can Be Done Next, Parijata Prabhakara

Dissertations, Master's Theses and Master's Reports

There is a lack of literature on the structural balance of systems (BOS), also called racking, for ground mount, fixed-tilt solar PV systems. Literature that exists discusses mostly rooftop racking and installations, additional wind loading, and weight considerations imposed on roofs, and little guidance is provided in building codes. The lack of peer-reviewed guidance on design requirements for domestic and large-scale application solar PV racking systems leaves most consumers relying on expensive, patented, off-the-shelf hardware. As PV cell technology and module costs have improved, we can start to focus on PV BOS improvements (particularly racking) and move towards sustainable designs …

Effect Of Flow Velocity And Geometry On The Signal From A Piezoelectric Flow Rate Sensor, Jad Gerges Aboud

Open Access Theses & Dissertations

.

Jominy Hardenability Tester With In-Situ Heating, Luke Allen

Williams Honors College, Honors Research Projects

This project centers on building a Jominy Hardenability tester with In-Situ heating for the manufacturing lab at the University of Akron. A new process and setup will be designed using engineering concepts in order to make the testing more efficient and safer for the teaching and testing of metal hardness. The current Jominy testing setup has efficiency issues within the transfer of specimen from induction heater to testing rig. Our design will simplify the design by creating a test rig that removes the traveling aspect of the specimen which will limit the amount of premature cooling done and will be …