Mechanical Engineering Commons^™

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 …

Elastomer O-Ring Seal Swell Measurements For Sustainable Aviation Fuel Material Compatibility, Conor J. Faulhaber

Honors Theses

As efforts continue to fight climate change by transitioning energy sources away from fossil fuels and towards renewable alternative, the commercial aviation sector finds itself at danger of falling behind in emissions reductions. To combat this, the best term opportunity to reduce the industry’s contribution to greenhouse gas emissions has been identified as sustainable aviation fuel, or SAF, derived from renewable feedstocks like agricultural waste or used cooking oil. Currently, SAF is regulated to a 50%v blending limit with conventional petroleum-based fuel to maintain certain jet fuel properties, including material compatibility with elastomer o-ring seals. When these seals come in …

Multi-Robot Symbolic Task And Motion Planning Leveraging Human Trust Models: Theory And Applications, Huanfei Zheng

All Dissertations

Multi-robot systems (MRS) can accomplish more complex tasks with two or more robots and have produced a broad set of applications. The presence of a human operator in an MRS can guarantee the safety of the task performing, but the human operators can be subject to heavier stress and cognitive workload in collaboration with the MRS than the single robot. It is significant for the MRS to have the provable correct task and motion planning solution for a complex task. That can reduce the human workload during supervising the task and improve the reliability of human-MRS collaboration. This dissertation relies …

Using Strategic Options Development And Analysis (Soda) To Understand The Simulation Accessibility Problem, Andrew J. Collins, Ying Thaviphoke, Antuela A. Tako

Engineering Management & Systems Engineering Faculty Publications

Simulation modelling is applied to a wide range of problems, including defense and healthcare. However, there is a concern within the simulation community that there is a limited use and implementation of simulation studies in practice. This suggests that despite its benefits, simulation may not be reaching its potential in making a real-world impact. The main reason for this could be that simulation tools are not widely accessible in industry. In this paper, we investigate the issues that affect simulation modelling accessibility through a workshop with simulation practitioners. We use Strategic Options Development and Analysis (SODA), a problem-structuring approach that …

A Method Of Assessing Peripheral Stent Abrasiveness Under Cyclic Deformations Experienced During Limb Movement, Courtney Keiser, Kaspars Maleckis, Pauline Struczewska, Majid Jadidi, Jason N. Mactaggart, Alexey Kamenskiy

Department of Mechanical and Materials Engineering: Faculty Publications

Poor outcomes of peripheral arterial disease stenting are often attributed to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our goals were to develop a method of assessing the abrasiveness of peripheral nitinol stents and apply it to several commercial devices. Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera stents were deployed inside electrospun nanofibrillar tubes with femoropopliteal artery-mimicking mechanical properties and subjected to cyclic axial compression …

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 …

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 …

Revealing The Pulse-Induced Electroplasticity By Decoupling Electron Wind Force, Xing Li, Qi Zhu, Youran Hong, He Zheng, Jian Wang, Jiangwei Wang, Ze Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

Micro/nano electromechanical systems and nanodevices often suffer from degradation under electrical pulse. However, the origin of pulse-induced degradation remains an open question. Herein, we investigate the defect dynamics in Au nanocrystals under pulse conditions. By decoupling the electron wind force via a properly-designed in situ TEM electropulsing experiment, we reveal a non-directional migration of Σ3{112} incoherent twin boundary upon electropulsing, in contrast to the expected directional migration under electron wind force. Quantitative analyses demonstrate that such exceptional incoherent twin boundary migration is governed by the electron-dislocation interaction that enhances the atom vibration at dislocation cores, rather than driven by the …

Application Of Direct Feedback Tunable Diode Laser Absorption Spectroscopy Within A Hybrid Rocket Combustor, Connor Becnel

LSU Master's Theses

With interest in space travel and space-related science increasing in recent years, significant efforts to reduce the cost and increase the safety of rocket motors have become commonplace. Liquid rockets are currently the most commonly used system, but there is interest in the reduced complexity of hybrid rockets. For these hybrid rocket motors to become the norm, extensive research on their complex boundary layer combustion needs to be performed. Modeling these hybrid systems is of much interest to companies developing rocket motors; ultimately, small-scale experiments will help validate their behavior. This paper covers the application of a near-infrared tunable diode …

Environmentally Balanced Approaches To Future Deep Seabed Mining, Jonatan J. Víctor Mendoza Alarcón

World Maritime University Dissertations

No abstract provided.

Injustice Within Renewable Energy Life Cycles: Can Irena Offer A Solution?, G. Webster Ross

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

This paper explores case studies of green colonialism, supply chain injustices, and poor e-waste management within renewable energy life cycles, and investigates how the International Renewable Energy Agency (IRENA) may be the best suited organization to address and mitigate these issues on a global scale. While renewable energy technology is often heralded as the key to a sustainable future, the life cycle of these technologies is riddled with human rights violations and other injustices. To begin with, many of the minerals required for assembling the hardware are mined in unregulated environments, resulting in several injustices such as health and safety …

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 …

Laser Surface Texturing Of Both Thin Polytetrafluoroethylene Coatings And Stainless Steel Substrates For Improving Tribological Properties, Firuze Soltani-Kordshuli, Charles Miller, Nathaniel Harris, Min Zou

Mechanical Engineering Faculty Publications and Presentations

Hilbert curve patterns were laser-textured on both stainless steel substrates and polytetrafluoroethylene (PTFE) thin coatings by applying 15% and 5% of the 2.3-W full laser power, respectively. The nanomechanical and tribological behavior of both smooth and laser-textured PTFE coatings on both smooth and laser-textured stainless steel substrates were studied. It was found that laser-texturing thin PTFE coatings reduced the hardness of PTFE coatings and prevented the coating from tearing under nanoindenter scratches. Furthermore, laser-texturing on both PTFE coatings and the stainless steel substrate improved the coating wear life 29 times compared to the wear life of the control sample without …

Highly Efficient, Perfect, Large Angular And Ultrawideband Solar Energy Absorber For Uv To Mir Range, Shobhit K. Patel, Arun Kumar Udayakumar, G. Mahendran, B. Vasudevan, Jaymit Surve, Juveriya Parmar

Department of Mechanical and Materials Engineering: Faculty Publications

Although different materials and designs have been tried in search of the ideal as well as ultrawideband light absorber, achieving ultra-broadband and robust unpolarized light absorption over a wide angular range has proven to be a major issue. Light-field regulation capabilities provided by optical metamaterials are a potential new technique for perfect absorbers. It is our goal to design and demonstrate an ultra-wideband solar absorber for the ultraviolet to a mid-infrared region that has an absorptivity of TE/TM light of 96.2% on average. In the visible, NIR, and MIR bands of the solar spectrum, the absorbed energy is determined to …

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 …

Tuning The Mechanical Behavior Of Density-Graded Elastomeric Foam Structures Via Interlayer Properties., Kazi Z Uddin, Ibnaj A Anni, George Youssef, Behrad Koohbor

Henry M. Rowan College of Engineering Departmental Research

The concept of density-graded foams has been proposed to simultaneously enhance strain energy dissipation and the load-bearing capacities at a reduced structural weight. From a practical perspective, the fabrication of density-graded foams is often achieved by stacking different foam densities. Under such conditions, the adhesive interlayer significantly affects the mechanical performance and failure modes of the structure. This work investigates the role of different adhesive layers on the mechanical and energy absorption behaviors of graded flexible foams with distinct density layers. Three adhesive candidates with different chemical, physical, and mechanical characteristics are used to assemble density-graded polyurea foam structures. The …

Imaging Diagnostics For Jet Breakup Into Droplets: A Review, Anu Osta

Henry M. Rowan College of Engineering Departmental Research

A concise review of the recent developments in some of the standard optical diagnostics applied for primary jet breakup studies has been presented here. Primary breakup is the core breakup of liquid jets and sheets into droplets upon its interaction with the ambient gaseous atmosphere. This phenomenon is encountered in various aerodynamic, fluid dynamic, and combustion situations. The imaging diagnostics reviewed here include photography, high-speed imaging, shadowgraphy, digital holography, ballistic imaging, jet core illumination, thermal imaging, Mie imaging, x-ray phase contrast imaging, and laser-induced fluorescence. The advantages and limitations of each technique, their success, and future developmental trend are discussed.

Visualization Of Cathode Spot Control Using Laser Irradiation And Oxide Addition In Wire Arc Additive Manufacturing Of Titanium Alloys, Tae Hyun Lee, Cheolhee Kim, Je Hoon Oh, Dong Hyuck Kam

Mechanical and Materials Engineering Faculty Publications and Presentations

Arc instability is one of the most critical problems in gas-metal-arc (GMA) based wire arc additive manufacturing of titanium (Ti) alloys. It can result in a poor bead surface, surface oxidation, and spattering. In particular, the relocation of the cathode spot area is the main cause of big spatters because of the high thermal energy of the molten droplet at the molten pool surface. In this study, two cathode spot control techniques were applied using auxiliary laser heating and prelaid oxides, and the behaviors of the cathode spots and arc were visualized using high-speed photography. When the laser beam was …

Large Refrigerant Capacity In Superparamagnetic Iron Nanoparticles Embedded In A Thin Film Matrix, Kaushik Sarkar, Surabhi Shaji, Jeffrey E. Shield, Christian H. Binek, Dhananjay Kumar

Department of Mechanical and Materials Engineering: Faculty Publications

A magnetocaloric effect (MCE) with sizable isothermal entropy change (ΔS) maintained over a broad range of temperatures above the blocking temperature is reported for a rare earth-free superparamagnetic nanoparticle system comprising of Fe–TiN heterostructure. Superparamagnetic iron (Fe) particles were embedded in a titanium nitride (TiN) thin film matrix in a TiN/Fe/TiN multilayered pattern using a pulsed laser deposition method. High angle annular dark-field images in conjunction with dispersive energy analysis, recorded using scanning transmission electron microscopy, show a clear presence of alternating layers of Fe and TiN with a distinct atomic number contrast between Fe particles and TiN. Quantitative information …

Study Into The Sensitity Of The G-H Method To Blending Distance, Cory Goates, Doug Hunsaker

Browse all Datasets

A numerical lifting-line method (implemented in an open-source software package) is presented which can accurately estimate the aerodynamics of wings with arbitrary sweep, dihedral, and twist. Previous numerical lifting-line methods have suffered from grid convergence challenges and limitations in accurately modeling the effects of sweep, or have relied on empirical relations for swept-wing parameters and have been limited in their application to typical wing geometries. This work presents novel improvements in accuracy, flexibility, and speed for complex geometries over previous methods. In the current work, thin-airfoil theory is used to correct section lift coefficients for sweep, providing a more general …

Investigation Of Polymer Nanocomposites With Silicon Dioxide Fillers As Helium Cooled High-Temperature Superconducting Cable Dielectrics, Jordan Thomas Cook

Theses and Dissertations

In this thesis, three polymer nanocomposite configurations are fabricated for investigation as dielectrics in helium-cooled high-temperature superconducting (HTS) cables. Polyimide, polyamide, and polymethyl methacrylate are utilized as host polymers. The composite samples are synthesized through an in situ process, dispersing silicon dioxide nanoparticles throughout the polymer hosts. Fourier transform infrared spectroscopy and scanning electron microscopy were employed to validate the synthesis of each composite configuration. Thin film samples of each configuration were also tested for their dielectric strength at both room (300 K) and cryogenic (92 K) temperatures. When going from room to cryogenic temperatures, all materials demonstrated a significant …

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 …

Dehumidification Performance Of A Variable Speed Heat Pump And A Single Speed Heat Pump With And Without Dehumidification Capabilities In A Warm And Humid Climate, Koukouni P. Kone, Nelson Fumo

Mechanical Engineering Faculty Publications and Presentations

Conventional air conditioning systems in houses respond to thermal loads by means of controlling dry-bulb temperature through the thermostat. As part of the process to control temperature, dehumidification is also provided. However, as houses are becoming more efficient, supplemental dehumidification is often necessary for homes located in hot and humid climates to control relative humidity intentionally. This study compared the dehumidification performance of a residential air conditioning system working in three operations modes to emulate three different systems: a system with a variable speed mode, a single-speed system with an enhanced dehumidification mode, and a single-speed system operating in a …

Experimental Investigation Of Low Velocity And High Temperature Solid Particle Impact Erosion Wear, Evan Gietzen, Soroor Karimi, Nipun Goel, Siamack A. Shirazi, Michael Keller, Todd Otanicar

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Next generation Concentrating Solar Power (CSP) plants utilizing solid particles as the heat transfer medium (HTM) are expected to achieve greater operational efficiencies. However, the erosion from the solid particles can cause significant damage to component materials. Low particle speeds (1–2 m/s) are proposed as a means of preventing excessive damage to containment materials. Within the current investigation, solid particle erosion of three potential containment materials, stainless-steel grade 316L, a nickel alloy (Inconel 740H), and a refractory material (Tufcrete 60 M), are examined at a particle impact speed of 1.6 m/s. CarboBead-HSP 40/70 particles, a candidate HTM for CSP systems, …

A Nanofiber-Embedded Microfluidic Platform For Studying Neurobiology, Donghee Lee, Navatha Shree Sharma, S. M. Shatil Shahriar, Kai Yang, Zheng Yan, Jingwei Xie

Department of Mechanical and Materials Engineering: Faculty Publications

Due to their biomimetic properties, electrospun nanofibers have been widely used in neurobiology studies. However, mechanistic understanding of cell-nanofiber interactions is challenging based on the current in vitro culture systems due to the lack of control of spatiotemporal patterning of cells and difficulty in monitoring single cell behavior. To overcome these issues, we apply microfluidic technology in combination with electrospun nanofibers for in vitro studies of interactions between neurons and nanofiber materials. We demonstrate a unique nanofiber embedded microfluidic device which contains patterned aligned or random electrospun nanofibers as a new culture system. With this device, we test how different …

A Survey Of Smart Manufacturing For High-Mix Low-Volume Production In Defense And Aerospace Industries, Tanjida Tahmina, Mauro Garcia, Zhaohui Geng, Bopaya Bidanda

Manufacturing & Industrial Engineering Faculty Publications

Defense and aerospace industries usually possess unique high-mix low-volume production characteristics. This uniqueness generally calls for prohibitive production costs and long production lead-time. One of the major trends in advanced, smart manufacturing is to be more responsive and better readiness while ensuring the same or higher production quality and lower cost. This study reviews the state-of-the-art manufacturing technologies to solve these issues and previews two levels of flexibility, i.e., system and process, that could potentially reduce the costs while increasing the production volume in such a scenario. The main contribution of the work includes an assessment of the current solutions …

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.