Digital Commons Network^™

Improvements To The Automatic Calibration Of Digital Focusing Color Schlieren Systems, Robert C. Frazee

LSU Master's Theses

As a diagnostic method, Schlieren imaging offers the unique ability to visualize flows with a completely non-intrusive method. By visualizing small changes in the refractive index of a fluid, Schlieren imaging is able to visualize changes in temperature, pressure, and composition. While historic Schlieren methods have been limited to providing largely qualitative information, modern Schlieren methods are able to extract quantitative information from flow phenomena. This is possible through either Background Oriented Schlieren (BOS) or Digital Focusing Color Schlieren (DFCS) methods. While BOS is relatively flexible, it requires a large amount of computational effort to process each frame of captured …

Simulation Of Supercritical Multiphase Flows Using Machine Learning, Nelson P. Longmire

Mechanical Engineering ETDs

In many technologies, such as rocket engines and modern power plants, the pressures of the fluids in these systems have increased to increase efficiency. As a result, the fluids are under pressures higher than the critical pressure meaning the fluids are supercritical. Supercritical fluids are unique as a liquid/gas phase equilibrium no longer exists, and a process called pseudo boiling occurs where the fluid properties have steep gradients, which lead to interesting fluid mechanics and heat transfer characteristics. Our understanding of supercritical fluids has had exciting advances over the years. However, there are still phenomena that are still not well …

Meshless Large Eddy Simulation Of Propeller-Wing Interactions With Reformulated Vortex Particle Method, Eduardo Alvarez, Andrew Ning

Faculty Publications

The vortex particle method (VPM) has gained popularity in recent years due to a growing need to predict complex aerodynamic interactions during preliminary design of electric multirotor aircraft. However, VPM is known to be numerically unstable when vortical structures break down close to the turbulent regime. In recent work, the VPM has been reformulated as a large eddy simulation (LES) in a scheme that is both meshless and numerically stable, without increasing its computational cost. In this study, we build upon this meshless LES scheme to create a solver for interactional aerodynamics. Rotor blades are introduced through an actuator line …

Sensitivity Analysis Of Frost Deposition In Turbulent Flow Over A Cold Plate Using Direct Numerical Simulation, N. Farzaneh, ‪Nadim Zgheib, S. A. Sherif, S. Balachandar

Mechanical Engineering Faculty Publications

We use a recently-developed, turbulence-informed physics-based model to study frost buildup over a flat plate subjected to turbulent flow. The plate temperature is held fixed but varied across simulations in the range −10◦C ≤ T∗ p ≤ −5◦C. Similarly, the free-stream temperature and humidity ratio are also held fixed but varied across simulations in the range 0◦C ≤ T∗∞ ≤ 20◦C and 3.77 × 10−3 ≤ ew∞ ≤ 1.47×10−2, respectively. We find the Nusselt and Sherwood numbers, when scaled by the frost surface to free stream temperature and humidity ratio difference, respectively, to become independent of free-stream temperature and humidity …

How Dynamic Adsorption Controls Surfactant‑Enhanced Boiling, Mario R. Mata, Brandon Ortiz, Dhruv Luhar, Vesper Evereux, H. Jeremy Cho

Mechanical Engineering Faculty Research

Improving boiling is challenging due to the unpredictable nature of bubbles. One way to enhance boiling is with surfactants, which alter the solid–liquid and liquid–vapor interfaces. The conventional wisdom established by previous studies suggests that heat transfer enhancement is optimized near the critical micelle concentration (CMC), which is an equilibrium property that depends on surfactant type. However, these studies only tested a limited number of surfactants over small concentration ranges. Here, we test a larger variety of nonionic and anionic surfactants over the widest concentration range and find that a universal, optimal concentration range exists, irrespective of CMC. To explain …

Finite Element-Based Machine Learning Model For Predicting The Mechanical Properties Of Composite Hydrogels, Yasin Shokrollahi, Pengfei Dong, Peshala T. Gamage, Nashaita Patrawalla, Vipuil Kishore, Hozhabr Mozafari, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

In this study, a finite element (FE)-based machine learning model was developed to predict the mechanical properties of bioglass (BG)-collagen (COL) composite hydrogels. Based on the experimental observation of BG-COL composite hydrogels with scanning electron microscope, 2000 microstructural images with randomly distributed BG particles were created. The BG particles have diameters ranging from 0.5 μm to 1.5 μm and a volume fraction from 17% to 59%. FE simulations of tensile testing were performed for calculating the Young’s modulus and Poisson’s ratio of 2000 microstructures. The microstructural images and the calculated Young’s modulus and Poisson’s ratio by FE simulation were used …

Computational Simulations Of The Effects Of Gravity On Lymphatic Transport, Huabing Li, Huajian Wei, Timothy P. Padera, James W. Baish, Lance L. Munn

Faculty Journal Articles

Physical forces, including mechanical stretch, fluid pressure, and shear forces alter lymphatic vessel contractions and lymph flow. Gravitational forces can affect these forces, resulting in altered lymphatic transport, but the mechanisms involved have not been studied in detail. Here, we combine a lattice Boltzmann-based fluid dynamics computational model with known lymphatic mechanobiological mechanisms to investigate the movement of fluid through a lymphatic vessel under the effects of gravity that may either oppose or assist flow. Regularly spaced, mechanical bi-leaflet valves in the vessel enforce net positive flow as the vessel walls contract autonomously in response to calcium and nitric oxide …

A Study Into Proton Exchange Membrane Fuel Cell Power And Voltage Prediction Using Artificial Neural Network, Tabbi Wilberforce, Mohammad Biswas

Mechanical Engineering Faculty Publications and Presentations

Polymer Electrolyte Membrane fuel cell (PEMFC) uses hydrogen as fuel to generate electricity and by-product water at relatively low operating temperatures, which is environmentally friendly. Since PEMFC performance characteristics are inherently nonlinear and related, predicting the best performance for the different operating conditions is essential to improve the system's efficiency. Thus, modeling using artificial neural networks (ANN) to predict its performance can significantly improve the capabilities of handling multi-variable nonlinear performance of the PEMFC. This paper predicts the electrical performance of a PEMFC stack under various operating conditions. The four input terms for the 5 W PEMFC include anode and …

Keys To Genus Of Calanoid Copepods Of China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Calanoid Copepods Of China Seas, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

Calanoid copepods are a well-recognized taxonomic group of Crustacea. They were already placed, with one cyclopoid (Scribella) and five calanoid (Acartia, Calanus, Candacia, Euchirus (= Euchaeta), and Pontella) genera, under a single taxonomic unit, the Calanidae, by Dana [1]. Giesbrecht and Sars are the two early principal contributors to the taxonomy of Copepoda, including the Calanoida.

Based on the location of the body articulation, Giesbrecht [2] divided copepods into two groups, the Gymnopleoden and Podopleoden. All copepods, characterized by an articulation between the fifth pedigerous (leg-bearing) somite and genital somite, separating the body into an anterior part (prosome) and a …

Calanoid Copepods Of China Seas-Introduction And Acknowledgement, Chang-Tai Shih, Qing-Chao Chen, Yang-Chi Lan, Shih-Hui Hsiao, Chi-Yu Weng

Journal of Marine Science and Technology–Taiwan

No abstract provided.

Optimal Synthesis Of Crank-Rocker Mechanisms With Optimum Transmission Angle For Desired Stroke And Time-Ratio Using Genetic Programming, Bahman Ahmadi, Behnam Ahmadi

Michigan Tech Publications, Part 1

Dimensional synthesis of crank-rocker mechanisms applied to provide some desired values of stroke and time ratio, is of utmost importance for designing an efficient mechanism. In the synthesis and manufacturing of crank-rocker mechanisms, the designers are further challenged by other design criteria, such as quality of motion. In this study, a novel approach based on genetic programming (GP) is proposed for dimensional synthesis of planar crank-rocker mechanisms with optimum transmission angle over the desired stroke and time-ratio. An analytical approach is elaborated which leads to an interesting relationship of length of the coupler and rocker links. It is, therefore, advised …

Analysis Of Mechatronically Controlled Turbines And Their Layout Schemes Used In Middle-Class Internal Combustion Engines, F Umerov, A Yangibaev

Technical science and innovation

This article will talk about the prospects for the possible use of gas-cylinder equipment on turbine internal combustion engines with a direct power supply system, consider the main possible methods of using such equipment and their results, identifying the best among them, taking such well-known car models as Chevrolet Tracker and Chevrolet Onyx as an example. Today there is an increase in the trend of transferring the car to two fuel supply. Installing gas-cylinder equipment on a turbo has also become quite popular. It is not difficult to make such a translation. It is only important to do this in …

The Vibration Sources Of Car Tractor Attachments, Sh Kh Kurbanov, U A. Rajapbayev

Technical science and innovation

This article presents measures to protect against the noise of operators during the work of machine-tractor units, and to prevent the occurrence of vibration as a result of tractor movement during work. Methods of acoustic processing of noise and vibration D-144; It has been proven that the noise characteristics of D-240T engines vary depending on the frequency of rotation of the crankshaft.

Preface For Millard Beatty, E. Baesu, Roger Fosdick

Department of Mechanical and Materials Engineering: Faculty Publications

Professor Beatty has contributed a wide variety of research papers and book articles on topics in finite elasticity, continuum mechanics and classical mechanics, including some fundamental experimental work. His works are clear and informative and expose a didactic quality. In the following, we briefly touch upon some of the highlights of his research involvement throughout the years.

Impulse, Fall 2022, University Marketing And Communications, Jerome J. Lohr College Of Engineering

Impulse (Jerome J. Lohr College of Engineering Publication)

2 | Sanjeev Kumar Takes Helm as College’s 12th Dean
5 | College Develops Partnerships in India, Turkey
6 | Faculty News
8 | Aerofly — Profs, Alum Partner To Build Unique Drone
10 | Researchers Find Way to Extend Produce Shelf Life
12 | SDSU Claims National Title in Quarter-Scale Tractors
14 | Nation’s Top ASCE Chapter Housed at SDSU
16 | National Geo-Video Title Won By State Students
18 | Summer Brings Engineering Camps to Campus
20 | Haleigh Timmer — Money on the Court, In Classroom
22 | Daniel Burkhalter — Day in the Life of Student-Athlete …

Nemesis Setup For Indirect Detection Of Wimps, W. H. Trzaska, Alexander Barzilov, T. Enqvist, K. Jedrzejczak, J. Joutsenvaara, M. Kasztelan, O. Kotavaara, P. Kuusiniemi, K. K. Loo, J. Orzechowski, J. Puputti, M. Slupecki, J. Szabelski, I. Usoskin, T. E. Ward

Mechanical Engineering Faculty Research

We summarize the evidence for DM-like anomalies in neutron multiplicity spectra collected underground with Pb targets by three independent experiments: NEMESIS (at 210 m.w.e.) NMDS (at 583 m.w.e.), and ZEPLIN-II (at 2850 m.w.e.). A new analysis shows small but persistent anomalies at high neutron multiplicities. Adjusted for differences in detection efficiencies, the positions of the anomalies are consistent between the three systems. Also, the intensities match when corrected for the acquisition time and estimated detection efficiency. While the three measurements are inconclusive when analyzed separately, together, they exclude a statistical fluke to better than one in a million. To prove …

Mems411: We Rock N’ Roverin', Amy L. Xue, Ash Caine, Emily Ma

Mechanical Engineering Design Project Class

The goal of this project is to create a remotely-controlled rover that can reliably collect dice. The customer, Chiamaka Asinugo, requires a device that meets the needs of a potential challenge that the WURocketry Team might face in future “NASA Student Launch” competitions. These needs include the rover being able to fit into a theoretical payload cylinder that is 5.36" in diameter and 8.5" long and the rover weighing less than 3.5 lbs.

Mems 411: Cnc Fabric Dispenser, Hayato Takai, Lizbet Suarez Mendoza, Jp Bermudez, Jeffrey Dai

Mechanical Engineering Design Project Class

This project aims to help Mary Ruppert-Stroescu with her zero-waste fashion project. The goal of this tool is to help Mary efficiently lay down fabric across a sheet of sticky paper to make a yard of reused fabric. The goal of our team was to create a machine that can work alongside Mary, rather than having her spend all her time at the machine. We wanted to make a machine that can work independently of Mary, so that she can focus her time on other things.

100s of lbs of fabric waste is part of American today. Mary's mission is …

Mems 411: Softball Pitching Machine, Sebastian Laboy, Molly Mcnamara, Thomas Burke

Mechanical Engineering Design Project Class

This report includes our complete final project for MEMS 411 in the Fall 2022 semester. For this project, we chose to fill the need for a pitching machine solely focused on the needs of softball players. For this project, our customer is a collegiate softball player named McKenna Jablonske.

Mems 411: Frame Redesign For A Dac Machine, Alyssa Bolander, Aaron Lombardi, Harry Hixson

Mechanical Engineering Design Project Class

This report focuses on the redesign of a 3’’ T-slot aluminum DAC frame. This design process focuses on minimizing cost and fasteners as the new frame will be made out of welded square steel tubing.

Mems 411: T-Shirt Strip Dispenser, Andrei Schwartz, Evan Dorsel, Amy Gong, Rosie Finglass

Mechanical Engineering Design Project Class

Develop a device to facilitate the t-shirt strip lay down process for Prof. Mary Ruppert-Stroescu

Mems 411: Fire Temperature Gradient Sensor, Anna-Sophia Eberhardt, Dexter Allen, Christopher Allen, Mikayla Jenkins

Mechanical Engineering Design Project Class

Fire Temperature Gradient Sensor to understand the interaction between prescribed forest floor burns and tick-borne disease ecology.

Aircraft Engine Particulate Matter Emissions From Sustainable Aviation Fuels: Results From Ground-Based Measurements During The Nasa/Dlr Campaign Eclif2/Nd-Max, Tobias Schripp, Bruce E. Anderson, Uwe Bauder, Bastian Rauch, Joel C. Corbin, Greg J. Smallwood, Prem Lobo, Ewan C. Crosbie, Michael A. Shook, Richard C. Miake-Lye, Zhenhong Yu, Andrew Freedman, Philip D. Whitefield, Claire E. Robinson

Chemistry Faculty Research & Creative Works

The use of alternative jet fuels by commercial aviation has increased substantially in recent years. Beside the reduction of carbon dioxide emission, the use of sustainable aviation fuels (SAF) may have a positive impact on the reduction of particulate emissions. This study summarizes the results from a ground-based measurement activity conducted in January 2018 as part of the ECLIF2/ND-MAX campaign in Ramstein, Germany. Two fossil reference kerosenes and three different blends with the renewable fuel component HEFA-SPK (Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene) were burned in an A320 with V2527-A5 engines to investigate the effect of fuel naphthalene/aromatic …

High-Throughput Computation Of Interfacial Thermal Management Of Wide-Bandgap Semiconductors, Hao-Wen Chen

Theses and Dissertations

As semiconductor electronics, in particular high electron mobility transistors, get hot in operation, people are trying to incorporate different semiconductor materials to solve the problem of heat dissipation to maintain the device efficiency and performance. In this master thesis, two different packages, LAMMPS and almaBTE, that are focusing on micro-scale and atomic scale respectively, are used to simulate the heat transfer process across interfaces in two different scales. In the LAMMPS simulation, the research is exploring how the location of atoms and the thickness of interfacial layers will influence the interfacial thermal conductance. On the other hand, using the almaBTE …

Shear Localization In The Metallic Nanolayered Composites, Shujing Dong

Theses and Dissertations

In this dissertation, the influences of layer thickness (h), interface orientation relationship (OR) and dislocation slip activities on shear band (SB) formation mechanisms was investigated by means of molecular dynamics (MD) simulations.

The effect of h and dislocation slip systems on the shear localization in Cu-FCC/Nb-BCC MNCs was studied. The strain softening observed in those samples was triggered by the SB formation. The microstructure evolutions and dislocation slips revealed that the unsymmetrical dislocation transmission across the interface induces the shear localization and promotes the SB formation. The quantitative analysis of the change in the separation distance of initially …

A Hybrid Experimental-Computational Study: Prediction Of Flow Fields And Full-Field Pressure Distributions On Three-Tab Asphalt Roofing Shingles Subjected To Hurricane Velocity Winds, Troy A. Myers

Theses and Dissertations

A novel hybrid experimental-computational study is performed to predict the flow fields and pressure distributions on the measured shapes of flexible, three-tab asphalt roofing shingles undergoing increasing uplift when exposed to hurricane velocity winds. StereoDIC analysis is performed to measure the transient full-field deformed shapes of full-size three-tab asphalt shingles when subjected to hurricane velocity winds for two hours. Steady state computational fluid dynamics (CFD) simulations of the shingled roof facsimile-plenum region representative of the experiments are successfully performed. The simulations are performed to predict wind loading of the uplifted shingle shapes by utilizing the measured full-field three-dimensional uplifted shapes …

Planar Compliance Realization With Two 3-Joint Serial Mechanisms, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

In this paper, the realization of any specified planar compliance with two 3R serial elastic mechanisms is addressed. Using the concept of dual elastic mechanisms, it is shown that the realization of a compliant behavior with two serial mechanisms connected in parallel is equivalent to its realization with a 6-spring fully parallel mechanism. Since the spring axes of a 6-spring parallel mechanism indicate the geometry of a dual 3R serial mechanism, a new synthesis procedure for the realization of a stiffness matrix with a 6-spring parallel mechanism is first developed. Then, this result is extended to a geometric construction-based synthesis …

Investigation Of Adhesion, Deformation Mechanics, And Electrical Properties Of Ag/Sio2/Pdms Tri-Layers For Stretchable Electronic Applications, Rhandy Joe Paladines

Theses and Dissertations

The motivation behind this research is to improve the interfacial layer bonding of metallic thin films to PDMS substrates with the aid of a buffer layer. The physical vapor deposition (PVD) technique of sputtering was used to deposit bilayer thin films of silver (Ag) and silicon dioxide (SiO2) on PDMS. Two chamber pressures were used in this work, 5 and 20 mTorr, to investigate the role of this parameter in determining the interfacial adhesion and the role in determining the resistance sensitivity. Studies of the surface energy and increased bonding strength for metallization are carried out. Surface characterization using atomic …

A Cfd-Based Scaling Analysis On Liquid And Paint Droplets Moving Through A Weak Concurrent Airflow Stream, Masoud Arabghahestani, Nelson Akafuah, Tianxiang Li, Kozo Saito

Progress in Scale Modeling, an International Journal

We conducted volume of fluids (VOF) multiphase model numerical simulations to obtain the interaction among all the major governing forces identified in our previous paper. Our numerical experiments are intended to assess the droplet generation process and the jetting behavior by providing specific input conditions, offering CFD as a tool to study scaling correlations instead of physical experiments. Water droplets that can represent waterborne paints were generated by piezo-generated sinusoidal waveforms at the inlet of the nozzle. The governing forces included the external piezo-based wave-generation force, the inertial force of droplets, the inertial force of air, the viscose force of …