Engineering Commons^™

Facile Production Of Large-Area Cell Arrays Using Surface-Assembled Microdroplets, Karla Perez-Toralla, Angel Olivera-Torres, Mark A. Rose, Amir Monemian Monemianesfahani, Keerthana Reddy, Ruiguo Yang, Stephen Morin

Department of Mechanical and Materials Engineering: Faculty Publications

Techniques that enable the spatial arrangement of living cells into defined patterns are broadly applicable to tissue engineering, drug screening, and cell–cell investigations. Achieving large-scale patterning with single-cell resolution while minimizing cell stress/damage is, however, technically challenging using existing methods. Here, a facile and highly scalable technique for the rational design of reconfigurable arrays of cells is reported. Specifically, microdroplets of cell suspensions are assembled using stretchable surface-chemical patterns which, following incubation, yield ordered arrays of cells. The microdroplets are generated using a microfluidic- based aerosol spray nozzle that enables control of the volume/size of the droplets delivered to the …

Characteristic Boundaries Associated With Three-Dimensional Twins In Hexagonal Metals, Shujuan Wang, Mingyu Gong, Rodney J. Mccabe, Laurent Capolungo, Jian Wang, Carlos N. Tomé

Department of Mechanical and Materials Engineering: Faculty Publications

Twinning is a critically important deformation mode in hexagonal close-packed metals. Twins are three-dimensional (3D) domains, whose growth is mediated by the motion of facets bounding the 3D twin domains and influences work hardening in metals. An understanding of twin transformations therefore necessitates that the atomic-scale structure and intrinsic mobilities of facets be known and characterized. The present work addresses the former point by systematically characterizing the boundary structures of 3D { ̄1012} twins in magnesium using high-resolution transmission electron microscopy (HRTEM). Eight characteristic facets associated with twin boundaries are reported, five of which have never been experimentally observed before. …

Fluid Mechanics Education Using Japanese Anime: Examples From “Castle In The Sky” By Hayao Miyazaki, Sangjin Ryu, Haipeng Zhang, Markeya S. Peteranetz, Tareq Daher

Department of Mechanical and Materials Engineering: Faculty Publications

Current K-12 and undergraduate student have grown up with constant exposure to visual popular culture (e.g., movies, TV programs, graphic novels, etc.). Because youth find pop culture references in the classroom to be engaging, many science and engineering instructors have shown that examples found in visual pop culture can be used to teach science and engineering concepts.1,2 One recent study on the efficay os using pop ulture for instruction found that high school studetns learning from graphic-novel styles comics acquired deeper understanding of complex subject matter and reported higher engagement with the instructional materials as compared to students learning from …

Rotating-Liquid-Based Hydrogel Bead Generator, Haipeng Zhang, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Hydrogel beads are widely used in various applications, but producing such beads often requires complicated devices. Instead, we propose an easy-to-adopt, cost effective, open source hydrogel bead generator. This generator consists of two modules. The first module rotates two immiscible liquids in rigid body motion: mineral oil as the continuous phase (CP) liquid on top, and a hydrogel cross-linking (CL) liquid at bottom. The second module injects a hydrogel pre-polymer solution as the dispersed phase (DP) liquid into the rotating CP liquid. As the DP liquid flows out of a syringe needle, its drops are pinched off by the shear …

Assistive Rehabilitation Elliptical System, Carl Nelson, Cale J. Stolle, Judith M. Burnfield, Thad W. Buster, Bernadette Mccrory

Department of Mechanical and Materials Engineering: Faculty Publications

An elliptical system is disclosed having a crank assembly configured to be adjusted in length to accommodate users having varying gaits. In some embodiments, the crank assembly includes a crank and an axle connection bracket that is slidably adjustable with respect to the crank. For example, the crank assembly can include a crank link having a longitudinal body, where the longitudinal body is connected to the crank at one end and includes a longitudinal slots slidably coupled with the axle connection bracket. The axle connection bracket is configured to slide through a plurality of positions along the longitudinal body. In …

Role Of Active Nanoliposomes In The Surface And Bulk Mechanical Properties Of Hybrid Hydrogels, R. Kadri, J. Bacharouch, K. Elkhoury, G. Ben Messaoud, C. Kahn, S. Desobry, M. Linder, Ali Tamayol, G. Francius, J.F. Mano, L. Sanchez-Gonzalez, E. Arab-Tehrany

Department of Mechanical and Materials Engineering: Faculty Publications

Nanoliposomes are widely used as delivery vehicles for active compounds. Nanoliposomes from rapeseed phospholipids were incorporated into interpenetrating polymer network hydrogels of gelatin methacryloyl and alginate. The multiscale physicochemical properties of the hydrogels are studied both on the surface and through the thickness of the 3D network. The obtained composite hydrogels exhibited strong mechanical properties and a highly porous surface. The blend ratio, as well as the concentration of nanoliposomes, affects the properties of the hydrogels. Nanofunctionalized hydrogels induced keratinocyte growth. These advantageous characteristics may open up many applications of the developed hydrogels in drug delivery and tissue engineering

Narrow Band Perovskite Single Crystal Photodetectors With Tunable Spectral Response, Jinsong Huang, Yanjun Fang

Department of Mechanical and Materials Engineering: Faculty Publications

Photoelectronic devices using perovskite single-crystal materials having a narrow spectral response, e.g., with a full-width-at-half-maximum response of less than about 20 nm, are provided. The response spectra are continuously (in frequency band) settable or tunable, e.g., from blue to red, by changing the halide composition and thus the band gap of the single crystals. The narrow-band response can be explained by the strong surface charge recombination of the excess carriers lose to the crystal surfaces generated by short wavelength light. The excess carriers generated by below-band gap excitation locate away from the surfaces and can be much more efficiently collect …

Crystallographic Orientation Dependence [email protected] Mechanical Responses Of Fecral Micropillars, Dongyue Xie, Binqiang Wei, Wenqian Wu, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Iron-chromium-aluminum (FeCrAl) alloys are used in automobile exhaust gas purifying systems and nuclear reactors due to its superior high-temperature oxidation and excellent corrosion resistance. Single-phase FeCrAl alloys with a body centered cubic structure plastically deform through dislocation slips at room temperature. Here, we investigated the orientation dependence of mechanical responses of FeCrAl alloy through testing single-crystal and bi-crystal micropillars in a scanning electron microscopy at room temperature. Single-crystal micropillars were fabricated with specific orientations which favor the activity of single slip system or two slip systems or multiple slip systems. The strain hardening rate and flow strength increase with increasing …

Hydrogel Microphone, Li Tan, Yang Gao, Qin Zhou, Yongmei Chen

Department of Mechanical and Materials Engineering: Faculty Publications

A device includes a capacitive sensor having a hydrogel structure that includes a first surface and a second surface. A first electrode is provided at the first surface of the hydrogel structure, the first electrode including a network of conductive nanoparticles extending into the hydrogel structure. A second electrode is provided at the second surface of the hydrogel structure.

Low Velocity Impact Of Hybrid Stacked Steel Plates, H. Hadidi, R. Q. Feng, M. P. Sealy

Department of Mechanical and Materials Engineering: Faculty Publications

Designing and manufacturing high-strength, low-weight parts with enhanced impact resistance is highly sought after in the transportation industry. The most common methods to improve strength-to-weight ratios of impact targets is a composite material composition or a favorable geometric design. An alternative method to improve impact performance is functionally gradient mechanical properties in a single material by hybrid additive stacking. In this study, low-velocity impact tests were conducted on hybrid stacked 1070 steel plates where individual layers were subjected to shot peening (SP) to functionally grade mechanical properties. Hybrid additive stacking refers to secondarily processing preferential layers within a stacked build …

Challenges In Path Planning Of High Energy Density Beams For Additive Manufacturing, Karunakaran K. P, Seema Negi, Arun Nambolan, Yogesh Patil, Milan Pandya, Sajan Kapil, Dmitriy Trushnikov, Michael P. Sealy, Alain Bernard

Department of Mechanical and Materials Engineering: Faculty Publications

As there are no cutting forces in High Energy Density (HED) beams like lasers and Electron Beam (EB), their speeds are limited only by their positioning systems. On the other hand, as the entire matrix of the 3D printed part has to be addressed by the thin beam in multiple passes in multiple layers, they have to travel several kilometers in tiny motions. Therefore, the acceleration of the motion system becomes the limiting factor than velocity or precision. The authors have proposed an area-filling strategy for EB to fill the layer with optimal squares to exploit analog and hardware computing. …

Adapting To Extreme Heat: Social, Atmospheric, And Infrastructure Impacts Of Air Conditioning In Megacities - The Case Of New York City, Harold Gamarro

Dissertations and Theses

Extreme heat events are becoming more frequent and intense in most large cities. Built-up surfaces also limit cooling mechanisms, leading to warmer conditions in cities, a phenomenon called the Urban Heat Island (UHI). This presents major challenges to reduce adverse health effects of hot weather, particularly in vulnerable populations like the elderly and low-income communities. Here we explore the overall impacts of increasing air conditioning (AC) system adoption in residences as an adaptive measure to reduce human health risks under heat waves, with New York City (NYC) as a case study. This study uses AC adoption data from the 2017 …

Toward Closing The Urban Surface Energy Balance Using Satellite Remote Sensing, Joshua Hrisko

Dissertations and Theses

The energy exchanges at the Earth’s surface are responsible for many of the processes that govern weather, climate, human health, and energy use. This exchange, commonly known as the surface energy balance (SEB), determines the near-surface thermodynamic state by partitioning the available energy into surface fluxes. The net all-wave radiation is often the primary energy source, while the heat storage and sensible and latent heat fluxes account for the majority of energy distributed elsewhere. While the SEB of various natural environments(trees, crops, soils) has been well-observed and modeled, the urban surface energy balance remains elusive. This is due to the …

Literature Review On Modeling Of Density Difference Pumping Strategy For Geothermal Applications, Lucas A. Ware

Graduate Theses, Dissertations, and Problem Reports (ETD)

The utilization of geothermal ground heat sources has been demonstrated at both large and small scales across the world. However, methods of extraction of the hot working fluids are often a source of energy inefficiency and high capital expense. Current techniques to extract geothermal fluids rely on mechanically and electrically driven down-hole components that require maintenance on a regular basis. In providing a solution, one approach that reduces complexity, decreases maintenance, and allows access to fluids at greater depth is an airlift approach. The airlift approach relies on injection of gas at a depth within a geothermal well to lift …

A Study On The Hydrodynamics Of A Bench-Scale Top-Fed Bubbling Fluidized Bed Gasifier Using Biomass And Coal As Feedstocks, Ali Can Sivri

Graduate Theses, Dissertations, and Problem Reports (ETD)

The production of synthetic gas (syngas) from renewable or carbon-neutral sources can significantly reduce greenhouse and other emissions associated with conventional fuels. One of the most promising technologies to efficiently convert carbonaceous feedstocks such as biomass, coal, or municipal waste into syngas for transportation, power, heat, electricity generation, and or production of added-value chemicals is the bubbling fluidized-bed gasifier (BFBG). However, the gasification process inside a BFBG is a very complex high-temperature multiphase flow phenomena still not well understood, particularly when binary mixtures are investigated. As a result, despite the numerous correlations in the literature developed to predict the hydrodynamics …

Environment Search Planning Subject To High Robot Localization Uncertainty, Jared Joseph Beard

Graduate Theses, Dissertations, and Problem Reports (ETD)

As robots find applications in more complex roles, ranging from search and rescue to healthcare and services, they must be robust to greater levels of localization uncertainty and uncertainty about their environments. Without consideration for such uncertainties, robots will not be able to compensate accordingly, potentially leading to mission failure or injury to bystanders. This work addresses the task of searching a 2D area while reducing localization uncertainty. Wherein, the environment provides low uncertainty pose updates from beacons with a short range, covering only part of the environment. Otherwise the robot localizes using dead reckoning, relying on wheel encoder and …

Influence Of Droplet Velocity, Spacing, And Inter-Arrival Time On Line Formation And Saturation In Binder Jet Additive Manufacturing, Trenton Colton, Nathan B. Crane

Faculty Publications

Binder Jetting (BJ) is a low-cost Additive Manufacturing (AM) process that uses inkjet technology to selectively bind particles in a powder bed. BJ relies on the ability to control, not only the placement of binder on the surface but also its imbibition into the powder bed. This is a complex process in which picoliter-sized droplets impact powder beds at velocities of 1-10 m/s. However, the effects of printing parameters such as droplet velocity, size, spacing, and inter-arrival time on saturation level (fraction of pore space filled with binder) and line formation (merging of droplets to form a line) are unknown. …

Development Of An Activity-Based Windowing Approach To Evaluate Real-World Nox Emissions From Modern Medium And Heavy-Duty Diesel Trucks, Rasik Pondicherry

Graduate Theses, Dissertations, and Problem Reports (ETD)

The introduction of in-use emissions regulations by the United States Environmental Protection Agency (U.S.EPA) requires medium-duty (MD) and heavy-duty (HD) engine manufacturers to demonstrate emissions compliance during in-fleet operation. In the United States (U.S.), the Not-to-Exceed (NTE) method is used to evaluate real-world emissions compliance from on-highway MD and HD trucks. Regulatory agencies, engine manufacturers and research entities have identified that the NTE method incorporates numerous exclusions and evaluates emissions compliance only under selective operating conditions that are favorable for the selective catalytic reduction (SCR) system to reduce oxides of nitrogen (NOx) emissions efficiently. Such operation is typically encountered only …

Development Of Bio-Based 2t Engine Oil In Marine Engine Application / Babooraman Shanmuganathan, Babooraman Shanmuganathan

Student Works (2020-2029)

Two-storke enginers are simple and lightweight two-cycle spark ignition engine with no oil sump is needed. The use of bio-based lubricants was analyzed to replace commercial mineral and synthetic-based lubricants. Lubricants were prepared by mixing three components of oil which comprise of base oil, additives, and solvent. In this research, four samples of base oil had been prepared with a different weight ratio of the PFAD-NPGester and Type II mineral. Then each of the simples were added with a similiar weight ratio of additives and solvent. A commercial lubricant was used as areference lubricant to be compared with samples prepared. …

A Numerical And Experimental Study On Effect Of Composition Of Ar-N2 Shielding Gas On The Weld Bead Profile And Its Prediction For Hot Wire Arc Additive Manufacturing, Niraj Pudasaini

College of Graduate Studies: Theses & Dissertations

Wire arc additive manufacturing is a process of making three-dimensional metal parts in a layer-by-layer approach using a feed wire and electric arc as a heat source. Wire arc additive manufacturing (WAAM) is becoming more popular due to its ability to create complex 3D parts, less build time, high deposition rate, and significant cost savings. Out of the many parameters used in WAAM, one of the important parameters is shielding gas which plays a significant role in material quality, properties, and defects. In this study, a controlled amount of Argon (Ar) and Nitrogen (N₂) shielding gases are used …

Experimental Evaluation Of Strength Degradation Temperature For Carbon Epoxy Filament Wound Composite, Jai Krishna Mishra, Surya Prakash Rao Ch Dr, Subhash Chandra Bose P Dr, Kishore Nath N Dr, Rama Rao Golla Mr

International Journal of Aviation, Aeronautics, and Aerospace

Polymeric composites have been widely used in various structural and thermal aerospace applications. Polymeric composites having high strength and high modulus reinforcement are ideally suited for lot of critical aerospace applications as structure is designed with high specific strength and high specific modulus. In case of launch vehicles/ missile one such application is design and manufacturing of solid rocket motor casing with polymeric composites as it give high performance and reduces inert weight of propulsion system. The high specific strength and high specific modulus of composite materials makes it ideal choice for designing the composite rocket motor case (CRMC). These …

Buckling Load Study On Pop Nut (Rivet) Using Finite Element Analysis, Saurabh Shankar Shegokar

Dissertations, Master's Theses and Master's Reports

This study highlights the material behavior in riveting operation that includes buckling load analysis using ABAQUS. Finite Element Analysis is used to find the buckling load vs. Displacement results and validated with the results obtained in physical testing of rivet (POP Nut). A mesh sensitivity study is performed using ABAQUS to understand the optimum mesh size for this analysis. An axisymmetric model with contact properties is created and simulated to reduce the simulation time using ABAQUS. The results obtained through Finite Element Analysis show a good resemblance with the testing results. Design changes were suggested to achieve better results that …

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

Department of Mechanical and 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 …

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

Department of Mechanical and 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 …

Mechanized Advent Calendar, Oma Skyrus, Sigrid Derickson, Tyler Koski, Daniel Clifton

Mechanical Engineering

Within this document, the “Naughty and Nice” team will describe the details associated with the completion of this project, which involves creating an animated advent calendar for the Cambria Christmas Market. The problem, the customers and stakeholders, and the general goals of the project are introduced. The team conducted background research; how this research helps in finding a solution or supporting the needs of the sponsor is illustrated. Initial research includes interviews with the sponsor and potential users, patent and existing product searches, and some technical research pertaining to the subject. The team found that there are not many existing …

Flight Test Data System For Strain Measurement, Zachary David Wilson

Master's Theses

This thesis describes the design and evaluation of two devices to be included in the next generation of the family of devices called the Boundary Layer Data System (BLDS). The first device, called the Quasi-Static Strain Data Acquisition System, is a continuation of the BLDS-M series of devices to be known as the Flight Test Data System (FTDS) that uses a modular approach to acquire non-flow, quasi-static mechanical strain measurements. Various breakout boards and development boards were used to synthesize the device, which were housed by a custom PCB board. The system is controlled by the Simblee^TM System on …

Multi-Scale Modeling Of The Lamellar Unit Of Arterial Media, Hozhabr Mozafari, Lulu Wang, Yuguo Lei, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The heterogeneity of the lamellar unit (LU) of arterial media plays an important role in the biomechanics of artery. Current two-component (fibrous component and a homogenous matrix) constitutive model is inappropriate for capturing the micro-structural variations in the LU, such as contraction/relaxation of vascular smooth muscle cells (VSMCs), fragmentation of the elastin layer, and deposition/disruption of the collagen network. In this work, we developed a representative volume element (RVE) model with detailed micro-configurations, i.e., VSMCs at various phenotypes, collagen fibers, and elastin laminate embedded in the ground substance. The fiber architecture was generated based on its volume fraction and orientations. …

Combined Molecular Dynamics And Phase Field Simulation Of Crystal Melt Interfacial Properties And Microstructure Evolution During Rapid Solidification Of Ti-Ni Alloys, Sepideh Kavousi

LSU Doctoral Dissertations

Phase field method has become a popular tool to investigate the microstructure evolution during the solidification. Quantitative predictions using this method is still limited, and in this dissertation, we try to study this problem from different perspectives.

Most of the phase field models consider the solid-liquid interface to be in local equilibrium. Solidification during some manufacturing processes like selective laser melting, and electron beam additive manufacturing is rapid and far from equilibrium which can result in supersaturated solid solutions, segregation-free crystals, or metastable phases. Before obtaining any conclusions from the phase field simulations, we must know the answer for “which …

Beyond The Toolpath: Site-Specific Melt Pool Size Control Enables Printing Of Extra-Toolpath Geometry In Laserwire-Based Directed Energy Deposition, Brian T. Gibson, Bradley S. Richardson, Tayler W. Undermann, Lonnie J. Love

Department of Mechanical and Materials Engineering: Faculty Publications

A variety of techniques have been utilized in metal additive manufacturing (AM) for melt pool size management, including modeling and feed-forward approaches. In a few cases, closed-loop control has been demonstrated. In this research, closed-loop melt pool size control for large-scale, laser wire-based directed energy deposition is demonstrated with a novel modification, i.e., site-specific changes to the controller setpoint were commanded at trigger points, the locations of which were generated by the projection of a secondary geometry onto the primary three-dimensional (3D) printed component geometry. The present work shows that, through this technique, it is possible to print a specific …

Effect Of Silica Fume In Concrete On Mechanical Properties And Dynamic Behaviors Under Impact Loading, Shijun Zhao, Qing Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

The effect of silica fume (SF) in concrete on mechanical properties and dynamic behaviors was experimentally studied by split Hopkinson pressure bar (SHPB) device with pulse shaping technique. Three series of concrete with 0, 12%, and 16% SF as a cement replacement by weight were produced firstly. Then the experimental procedure for dynamic tests of concrete specimens with SF under a high loading rate was presented. Considering the mechanical performance and behaviors of the concrete mixtures, those tests were conducted under five different impact velocities. The experimental results clearly show concrete with different levels of SF is a strain-rate sensitive …