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2019

Mechanical Engineering

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Full-Text Articles in Engineering

Modeling, Simulation, And Validation Of Process-Structure-Property Relationships In Fused Filament Fabrication, Aaron Grant Dec 2019

Modeling, Simulation, And Validation Of Process-Structure-Property Relationships In Fused Filament Fabrication, Aaron Grant

Electronic Theses and Dissertations

As additive manufacturing (AM) grows in popularity, the need for better simulation tools to predict the process-structure-property relationships of AM parts becomes ever more necessary to employ the technology in design of functional parts with varying degrees of complexity and performance requirements. Many simulation tools and techniques have been developed that aim to achieve this goal, and the main purpose of this research is to explore how well different simulation tools and modeling approaches can capture various AM-specific features such as inter-raster and end-of raster voids, and residual stresses induced by dissimilar rates of thermal expansion. Process simulation of fused ...


Quantitative Peel Test For Thin Films/Layers Based On A Coupled Parametric And Statistical Study, Maysam Rezaee, Li Chih Tsai, Muhammad Istiaque Haider, Armin Yazdi, Ehsan Sanatizadeh, Nathan P. Salowitz Dec 2019

Quantitative Peel Test For Thin Films/Layers Based On A Coupled Parametric And Statistical Study, Maysam Rezaee, Li Chih Tsai, Muhammad Istiaque Haider, Armin Yazdi, Ehsan Sanatizadeh, Nathan P. Salowitz

Mechanical Engineering Faculty Articles

The adhesion strength of thin films is critical to the durability of micro and nanofabricated devices. However, current testing methods are imprecise and do not produce quantitative results necessary for design specifications. The most common testing methods involve the manual application and removal of unspecified tape. This overcome many of the challenges of connecting to thin films to test their adhesion properties but different tapes, variation in manual application, and poorly controlled removal of tape can result in wide variation in resultant forces. Furthermore, the most common tests result in a qualitative ranking of film survival, not a measurement with ...


Failure Of High Strength Concrete Under Dynamic Uniaxial Compression, Colin Loeffler Dec 2019

Failure Of High Strength Concrete Under Dynamic Uniaxial Compression, Colin Loeffler

Mechanical Engineering Research Theses and Dissertations

The failure strength of concrete materials has been widely shown to be dependent on experimental parameters such as specimen geometry and strain-rate. The effects of specimen geometry have been shown both theoretically and experimentally to be a result of the quasi-brittle nature of concrete. While the failure strength of concrete has been widely reported to increase significantly when deformed at high strain-rates, the physical mechanisms driving this phenomenon remain the source of debate amongst researchers. This means that constitutive models designed to predict this rate dependent behavior are not based on the real physical mechanisms that drive this behavior but ...


Smart Factories, Dumb Policy? Managing Cybersecurity And Data Privacy Risks In The Industrial Internet Of Things, Scott J. Shackelford Dec 2019

Smart Factories, Dumb Policy? Managing Cybersecurity And Data Privacy Risks In The Industrial Internet Of Things, Scott J. Shackelford

Minnesota Journal of Law, Science & Technology

No abstract provided.


Generalized Ultrasonic Scattering Model For Arbitrary Transducer Configurations, Andrea P. Arguelles, Joseph A. Turner Dec 2019

Generalized Ultrasonic Scattering Model For Arbitrary Transducer Configurations, Andrea P. Arguelles, Joseph A. Turner

Mechanical & Materials Engineering Faculty Publications

Ultrasonic scattering in polycrystalline media is directly tied to microstructural features. As a result, modeling efforts of scattering from microstructure have been abundant. The inclusion of beam modeling for the ultrasonic transducers greatly simplified the ability to perform quantitative, fully calibrated experiments. In this article, a theoretical scattering model is generalized to allow for arbitrary source and receiver configurations, while accounting for beam behavior through the total propagation path. This extension elucidates the importance and potential of out-of-plane scattering modes in the context of microstructure characterization. The scattering coefficient is explicitly written for the case of statistical isotropy and ellipsoidal ...


Fft Phase Shift Of Water Wave Analysis, Chu-Kuan Lin, Shih-Yu Hsu, Jaw-Guei Lin Dec 2019

Fft Phase Shift Of Water Wave Analysis, Chu-Kuan Lin, Shih-Yu Hsu, Jaw-Guei Lin

Journal of Marine Science and Technology

The fast Fourier transform (FFT) has been accepted as a tool for signal processing. This study conducted a series of numerical experiments using Matlab. By conducting FFT analysis on designated wave trains, the FFT results revealed that an extra phase shift of ��ሺ2�� ��⁄ ሻ , with N representing the number of data points for an i-th wave component, was implicitly added to the analyzed phases during the analysis. When extra phase shifts were subtracted from the analyzed phases of each component, signals could be completely reconstructed in the time domain with an acceptable difference. This study tested component and non-component waveforms ...


Acoustic Design Optimization With Isogeometric Analysis And Differential Evolution, Garrett W. Dodgen Dec 2019

Acoustic Design Optimization With Isogeometric Analysis And Differential Evolution, Garrett W. Dodgen

Mechanical Engineering Theses

The objective of this study is to utilize shape optimization to enhance the performance of devices relying on acoustic wave propagation. Particularly, the shape of a horn speaker and an acoustic energy harvester were optimized to enhance their performance at targeted frequencies. High order Isogeometric Analysis (IGA) was performed to estimate the acoustic pressure with minimum geometry and pollution errors [1]. The analysis platform was then combined with Differential Evolution (DE) to optimize the geometry of the horn speaker and energy harvester at a given frequency. These cases effectively demonstrate two applications of Isogeomtric shape optimization for devices relying on ...


System And Method For Determining Operating Deflection Shapes Of A Structure Using Optical Techniques, Javad Baqersad Dec 2019

System And Method For Determining Operating Deflection Shapes Of A Structure Using Optical Techniques, Javad Baqersad

Mechanical Engineering Patents

A system for measuring total operating deflection shapes of a structure includes one or more imagers, each including two cameras spaced apart from one another and each oriented and positioned to have corresponding fields of view of a different corresponding section of the structure, with the corresponding sections that may include overlap area of the structure within each of the different sections of the structure. Each of the cameras generates a corresponding data stream, which is communicated to a controller, which is configured to measure the response of the structure to an excitation, such as a vibration or an impulse ...


Biomechanical Analysis Of Open-Skull High-Rate Traumatic Brain Injury Using Finite Element Mouse Brain Model, Lihong Lu Dec 2019

Biomechanical Analysis Of Open-Skull High-Rate Traumatic Brain Injury Using Finite Element Mouse Brain Model, Lihong Lu

Electronic Thesis and Dissertation Repository

To better understand traumatic brain injury (TBI), it is necessary to correlate with injuries, which are observed from in vivo laboratory experiments, to brain mechanical responses, which can so far be best predicted by finite element (FE) models. Firstly, a previously validated FE model was improved to investigate the effect of repeated impacts and lateral movements on brain responses to ensure the accuracy and reproducibility of controlled cortical impact (CCI) across different labs. Then, a new FE mouse brain model with the detailed three-dimensional (3D), non-linear vasculature was developed to study how the vasculature affected brain response in CCI and ...


Synthesis And Connection Of Iridium Hydrogen Evolution Catalyst To Chlorella Vulgaris Photosystem I For Light-Driven Hydrogen Evolution, Anna Ramirez Dec 2019

Synthesis And Connection Of Iridium Hydrogen Evolution Catalyst To Chlorella Vulgaris Photosystem I For Light-Driven Hydrogen Evolution, Anna Ramirez

Honors Program Theses and Projects

Hydrogen gas has been shown to be a promising energy source as options other than fossil fuels are being looked at in the face of anthropogenic climate change. It is known that anthropogenic climate change is caused by the production of greenhouse gases being let into the atmosphere, specifically a common reason for this is the burning of fossil fuels for energy. The overall goal of this project is to design a biochemical hybrid system that will be used to make H 2 gas and does not require the use of fossil fuels. Burning hydrogen as fuel produces only water ...


Group A: Asme Student Design Challenge, Dakshi Jindal, Ashley Perry, Ben Liao Dec 2019

Group A: Asme Student Design Challenge, Dakshi Jindal, Ashley Perry, Ben Liao

Mechanical Engineering Design Project Class

This year's student design competition is termed "Building to the Sky." Student teams are required to build a compact engineering system capable of manufacturing a tower made of only standard-sized sheets of paper.


Asme Design Challenge: The Jenga Stacker, Zachary Lin, Alex Chernauskas, Mitch Dorsey, Alex Remmers Dec 2019

Asme Design Challenge: The Jenga Stacker, Zachary Lin, Alex Chernauskas, Mitch Dorsey, Alex Remmers

Mechanical Engineering Design Project Class

The 2020 ASME Design Challenge requires teams to build a compact engineering system capable of manufacturing a tower made exclusively from standard-sized sheets of paper. The validation of the design will include testing for manufacturing speed, height of tower, and ability to support a load. Our senior design project focuses on the stacking mechanism and is designed to stack a 4 in x 4 in tower out of prepared 4 in x 1.5 in x 1.75 in paper boxes from the ground up.


Group E: Improved Greens Harvester, Paige Grittner, Paul Harding, Ned Curran, Jennifer Mata Dec 2019

Group E: Improved Greens Harvester, Paige Grittner, Paul Harding, Ned Curran, Jennifer Mata

Mechanical Engineering Design Project Class

The Improved Greens Harvester is a project designing an improved machine that will be used to harvest crops by our client, EarthDance Organic Farm School in Ferguson, MO. The goal of our design was to provide a simple, easy-to-use, and easyto-fix machine that would cut and collect baby green leaves as the user walks along the plant bed. We first sought to address issue with the client’s current machine including low cutting accuracy, strain on the user’s body, frequent jamming, and low efficiency. Our initial design was a cart design that included: an oscillating blade for cutting, a ...


Improved Greens Harvester, Sharon Park, Khalil Clark, Millyn Brieschke Dec 2019

Improved Greens Harvester, Sharon Park, Khalil Clark, Millyn Brieschke

Mechanical Engineering Design Project Class

This paper attempts to provide a prototype of the improved greens harvester. Some inconveniences of the users, including not able to cut greens at a constant length, greens getting clogged in between the brush and the basket, and the need to empty the basket a lot of times. This paper describes problem understanding, concept generation, concept selection, concept embodiment, working prototype, and design refinement. Through these analyses and processes, an improved greens harvester solving the inconveniences is designed. The improved greens harvester has a higher greens harvester with wheels that makes using the harvester less troublesome. Band saw is stuck ...


Group S- Arliss Project, Preston Bailey, Zach Stelwagon, Cal Reynolds, James Hardy Dec 2019

Group S- Arliss Project, Preston Bailey, Zach Stelwagon, Cal Reynolds, James Hardy

Mechanical Engineering Design Project Class

Our project was the ARLISS competition project, more specifically the second part of the project where the vehicle must survive a drop and drive to a known location over rough desert terrain. We interviewed our professor, Dr. Potter, who had previous experience with the project to understand what was required in our design. The project started with creating concept ideas and deciding on one, which initially was an airplane to avoid designing a landing mechanism and having to drive over rough terrain. However, this design proved to have too many flaws and was scrapped. The new design was a small ...


Development Of High-Speed Photoacoustic Imaging Technology And Its Applications In Biomedical Research, Yun He Dec 2019

Development Of High-Speed Photoacoustic Imaging Technology And Its Applications In Biomedical Research, Yun He

Engineering and Applied Science Theses & Dissertations

Photoacoustic (PA) tomography (PAT) is a novel imaging modality that combines the fine lateral resolution from optical imaging and the deep penetration from ultrasonic imaging, and provides rich optical-absorption–based images. PAT has been widely used in extracting structural and functional information from both ex vivo tissue samples to in vivo animals and humans with different length scales by imaging various endogenous and exogenous contrasts at the ultraviolet to infrared spectrum. For example, hemoglobin in red blood cells is of particular interest in PAT since it is one of the dominant absorbers in tissue at the visible wavelength.The main ...


Cfd Simulation Investigating The Effects Of Groove Geometry On Heat Transfer For Internally Grooved Tubes, Richard Zaven Saroukhanoff Dec 2019

Cfd Simulation Investigating The Effects Of Groove Geometry On Heat Transfer For Internally Grooved Tubes, Richard Zaven Saroukhanoff

UNLV Theses, Dissertations, Professional Papers, and Capstones

This numerical study investigates the thermal performance of internally grooved tubes used in heat exchangers. In order to enhance the performance of heat exchangers, turbulence promoters are inserted along the streamwise flow. The use of inserts, grooves, and augmentations along the axial length of the tube creates disturbances that improve the overall heat transfer due to enhanced fluid mixing and greater surface contact boundary walls. However, the implementation of tube wall augmentations creates an increase in pressure drop across the tube which must be compensated for with additional pumping power for the working fluid. Therefore, in order to analyze the ...


Ambient Temperature Dependence Of Air-Cooled Condenser Performance And Parameters, Alexander Darr Smith Dec 2019

Ambient Temperature Dependence Of Air-Cooled Condenser Performance And Parameters, Alexander Darr Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Thermoelectric power generation uses 38% of total fresh water withdrawals and majority of that water is used during steam condensation. Air-cooled condensers are an alternative to water-cooled condensers for power generation. Ambient air temperature affects the performance of air-cooled condensers. A small air-cooled condenser was run under the ambient air temperature extremes of Las Vegas in order to examine the system performance and air-side heat transfer parameters. Three different sets of tubes with different surface areas and geometries were studied. The condenser is equipped with several air velocity sensors, thermocouples and thermistors to measure the conditions to develop the air-side ...


3d Chocolate Printer Bed Design, Dean Oken, Jacob Margolin, Ben Hartmann, Sam Grossman Dec 2019

3d Chocolate Printer Bed Design, Dean Oken, Jacob Margolin, Ben Hartmann, Sam Grossman

Mechanical Engineering Design Project Class

The client wished for a device to gain the interest of young undergraduate students into basic thermal science and fluid dynamics concepts. A 3D printer bed was created from concept to prototype design and paired with chocolate dropper teams to complete the project and accomplish the client's goals.


Mems 411 Group L (Fall 2019) - Speedy Seeder Final Report, Michael Morrow, Christopher Nelson, Ross Frame Dec 2019

Mems 411 Group L (Fall 2019) - Speedy Seeder Final Report, Michael Morrow, Christopher Nelson, Ross Frame

Mechanical Engineering Design Project Class

The Speedy Seeder or ”SS” is a device designed to decrease the time it takes to fill one seed plot by hand to roughly sixteen percent of the time. The customer of the SS is EarthDance Organic Farms School. EarthDance fills a large number of plots each year by placing a seed in every single compartment which come in three sizes: 32, 72, and 128 compartments per plot. Filling a single plot by hand can take roughly 8 minutes. The SS makes filling a plot much easier and faster, allowing a single plot to be filled in under 75 seconds ...


Experimental Study Of Condensation In A Thermoacoustic Cooler With Various 3d Printed Regenerators Using Water Vapor As The Working Fluid, Aibek Bekkulov, Andrew Luthen, Ben Xu Dec 2019

Experimental Study Of Condensation In A Thermoacoustic Cooler With Various 3d Printed Regenerators Using Water Vapor As The Working Fluid, Aibek Bekkulov, Andrew Luthen, Ben Xu

Mechanical Engineering Faculty Publications and Presentations

Thermoacoustics (TA) deals with the conversion of heat into sound and vice versa. The device that transfers energy from a low temperature reservoir to a high temperature one by utilizing acoustic work is called TA cooler (TAC). The main components of a typical TAC are a resonator, a porous regenerator (e.g. stack of parallel plates) and two heat exchangers. The thermoacoustic phenomenon takes place in the regenerator where a nonzero temperature gradient is imposed, and interacts with the sound wave. The low temperature at the cold end of TAC can be used to condense water from the humid air ...


Integrated Design Approach For Coronary Stents Using Flexinol Shape Memory Alloy, Matthew Lucci Dec 2019

Integrated Design Approach For Coronary Stents Using Flexinol Shape Memory Alloy, Matthew Lucci

Mechanical Engineering Theses

This research seeks to develop and verify a model for control of the shape memory alloy (SMA) Flexinol and apply such findings to practical application of the material as a platform for bare metal stenting technologies. Utilizing experimental data and material properties, a mathematical model of the thermoelectric contraction behavior of Flexinol wire samples was developed. This model accounted for variable resistance due to the shape memory effect of the Flexinol wire as it experiences a crystalline phase change. It also accounted for the change in the cross-sectional area of the wire as the wire experienced thermal expansion and contraction ...


Energy Modelling To Evaluate The Thermal Regulation Of Aquaculture Raceways Using Geothermal Heat Exchange, Mitchell H. Kuska Dec 2019

Energy Modelling To Evaluate The Thermal Regulation Of Aquaculture Raceways Using Geothermal Heat Exchange, Mitchell H. Kuska

Electronic Thesis and Dissertation Repository

Raceways are used in the aquaculture industry to farm fish species that swim against an upstream current. Raceways often draw water from a large waterbody and hence, their temperature changes due to seasonal variation, which directly affect the production yield. This study investigates a novel approach to regulate the raceway water temperature in a sustainable way by utilizing geothermal energy exchange. Energy models were developed to simulate heat transfer in a geothermal borehole heat exchange system and in the raceway system. The two models were then coupled to simulate the thermal regulation of the raceway water via borehole heat exchangers ...


Numerical And Semi-Analytical Estimation Of Convective Heat Transfer Coefficient For Buildings In An Urban-Like Setting, Anwar Demsis Awol Dec 2019

Numerical And Semi-Analytical Estimation Of Convective Heat Transfer Coefficient For Buildings In An Urban-Like Setting, Anwar Demsis Awol

Electronic Thesis and Dissertation Repository

Urban building arrangements such as packing density, orientation and size are known to influence the microclimate surrounding each building. Studies on the impact of urban microclimatic changes on convective heat transfer coefficient (CHTC) from a stock of buildings, however, have been rare in surveyed literature. The present study focuses on numerical and analytical investigation of CHTC from building-like models with homogeneous set of equal and unequal planar and frontal densities. Consequently, the study discusses the CHTC response in relation to broader changes in the urban surface form. Part of the process involves the development of a simplified one-dimensional semi-analytical CHTC ...


Violin Bow-Hand Prosthetic, Jonathan Smith, Jonathon Azziz, Shawn Pavey Dec 2019

Violin Bow-Hand Prosthetic, Jonathan Smith, Jonathon Azziz, Shawn Pavey

Mechanical Engineering Design Project Class

The violin bow hand prosthetic was designed for a young violin player seeking to upgrade the functionality of his current violin prosthetic device. His current device is rigid, forcing him to play mostly with his shoulder. Since the strength of his wrist was unknown, we designed a prosthetic with enough brace flexibility to enable the user to control the bow motion with his own wrist. We also added an axis of rotation and spring mechanism to supplement this motion and provide him the equivalence of fine finger adjustments. The full design process of the prosthetic is documented in this report ...


Group M: Arliss Canister Vehicle, Greyson Bourgeois, Eleanor Macklin, Romail Dawani, Rachel Sample Dec 2019

Group M: Arliss Canister Vehicle, Greyson Bourgeois, Eleanor Macklin, Romail Dawani, Rachel Sample

Mechanical Engineering Design Project Class

This project is a dicycle designed for the ARLISS Canister Competition. In this competition, the device is loaded into a rocket which is then launched to about 12000 ft before releasing the device. Then it must safely land and autonomously navigate to a predetermined GPS location on the ground. Due to the fact that this is a mechanical engineering design project and the time restrictions of this class, we focused on the physical aspect of the project, such as building a device that can survive the launch and landing and traverse several kilometers through the desert, forgoing the autonomous navigation ...


T-Shirt Strip Dispenser, Maxwell Dimgba, Syeda Mohsin, Sabrina Nguyen Dec 2019

T-Shirt Strip Dispenser, Maxwell Dimgba, Syeda Mohsin, Sabrina Nguyen

Mechanical Engineering Design Project Class

There is a massive amount of waste around the textile industry. New garments are constantly being made and old garments are consistently finding themselves in landfills. This project aims to cut down on this waste. Mary Susan RuppertStroescu of the Sam Fox School at Washington University in St. Louis has developed a process to turn old garments into new ones in a practice known as up-cycling. By cutting old garments into half-inch strips, laying and adhering them flat on a sheet of dissolvable paper, and sewing over them in interesting patterns she is able to create extraordinary new designs. This ...


Violin Bow-Hand Prosthetic, Ron Hayes Jr, Kc Cook, Romario Lobban, Muriel Drexler Dec 2019

Violin Bow-Hand Prosthetic, Ron Hayes Jr, Kc Cook, Romario Lobban, Muriel Drexler

Mechanical Engineering Design Project Class

The violin bow-hand prosthetic aims to mimic the natural hold and motion of a violinist’s bow-hand. The prosthetic is for a violinist who is missing the majority of their hand, but still has full range of motion in the wrist. Focusing on maintaining a natural playing style greatly influenced the design of the device to be user safe, durable, comfortable, easy to use, inexpensive, and practical. Many of these features were achieved by using 3D printed plastic and foam composites. These materials were selected based on strength and deflection analyses of 3-D simulations performed in SolidWorks and the ease ...


Group N: Fluid Flow Testing Apparatus, Jonathan Fleming, Braden Kerr, Abel Soloman Dec 2019

Group N: Fluid Flow Testing Apparatus, Jonathan Fleming, Braden Kerr, Abel Soloman

Mechanical Engineering Design Project Class

A fluid flow testing apparatus was needed to accurately test valves relative to the conditions seen in the factory of a local St. Louis brewery. After concept generation, a rotating track that toggled the valve between open and closed was decided on by the team. Construction of an initial prototype was done over 3 weeks with a total budget of 400 USD. The initial prototype satisfied almost all of the performance goals: capable of cycling 200 times without intervention, 1 paper-towel of leakage at most, and upper reservoir level consistency within 10 percent. To improve the initial prototype, the team ...


Energy Performance Certification: Misassessment Due To Assuming Default Heat Losses, Ciara Ahern, Brian Norton Dec 2019

Energy Performance Certification: Misassessment Due To Assuming Default Heat Losses, Ciara Ahern, Brian Norton

Articles

Energy Performance Certificates (EPCs) are issued when dwellings are constructed, sold or leased in the EU. Where the cost of obtaining the required data is prohibitive, EPC assessors use nationally applicable default-values. To ensure that dwellings are not assigned a wrongly-higher EPC rating, a standardised thermal bridging transmittance coefficient (Y-value) is typically adopted for all existing dwellings while worst-case overall heat loss coefficients (U-values) are used. Default U-values are applied to a specific building element type (roof, wall, floor etc.) based on building codes and regulations applicable at time of construction. Due to significant building fabric upgrades, default U-values are ...