Geometric Analysis Of Insect Wing Vein Network,
2022
University of Nebraska at Omaha
Geometric Analysis Of Insect Wing Vein Network, Jacob White, Ying Hu, Sangjin Ryu, Seunghee Kim, Haipeng Zhang
Department of Mechanical and Materials Engineering: Faculty Publications
An insect wing consists of a thin membrane supported by a system of veins, and flow of blood through the system of veins is critical for maintaining healthy insect wings. Better understanding of the insect wing vein circulation requires to know how the efficiency of blood flow in an insect wing relates to the geometric shape of the vein. Our investigation of the wing vein network of a dragonfly Anax junius follows the idea of Murray’s law, which is established in the study of efficiency of the vein network and the geometric shape of the vein. Instead of using the …
Pressure-Induced Phase Transition And Electronic Structure Changes In Equiatomic Fev,
2022
University of Texas at El Paso
Pressure-Induced Phase Transition And Electronic Structure Changes In Equiatomic Fev, Homero Reyes Pulido
Open Access Theses & Dissertations
Classical molecular dynamics methods can accurately describe a broad set of many-atomssystems. Although more economical, the results given by this framework lack the precision capable of density functional theory (DFT). Therefore, the structural stability of the B2 phase of a body-centered-cubic iron-vanadium (FeV) alloy using DFT on the electronic structure level is analyzed to verify and further explain classical results obtained by our group in this same alloy. Using Quantum Espresso and Phonopy for the computational simulations, the plotted band structure, electronic density of states (eDOS), phonon dispersions, charge density, and Fermi surfaces for various compressed unit cells are presented. …
Characterization Of 3d Stereolithography (Sla) Printed Polymer For Autonomous-Flow Microfluidic Devices,
2022
University of Texas at El Paso
Characterization Of 3d Stereolithography (Sla) Printed Polymer For Autonomous-Flow Microfluidic Devices, Michelle Gamboa
Open Access Theses & Dissertations
3D Stereolithography (SLA) printing is a high-throughput, precise and reproducible manufacturing platform which makes it a desirable technique to develop microfluidic devices for bioanalytical applications. However, limited information exists regarding the physical, chemical, and biological properties of the polymer resins used in 3D SLA printing. This project demonstrates the characterization of a commercially available 3D SLA printed resin polymer used to develop an autonomous-flow (self-driven) microfluidic device. In this investigation, time-dependent materials characterization was done on the Formlabs clear V4 resin to observe changes in mechanical and surface properties. The clear, printed polymer was analyzed with attenuated total reflectance (ATR), …
Reflectance Spectral Characterization And Taxonomy Applications Of Spacecraft Materials To Aid Space Situational Awareness,
2022
University of Texas at El Paso
Reflectance Spectral Characterization And Taxonomy Applications Of Spacecraft Materials To Aid Space Situational Awareness, Jacqueline Andrea Reyes
Open Access Theses & Dissertations
The increasing number of space missions involving successfully deployed spacecraft have resulted in an augmented density of artificial objects positioned in orbital domains near Earth. With this steady accumulation of objects in space, it has become increasingly imperative to characterize spacecraft materials, which may ultimately be contributors to the orbital debris population. In an effort to identify unique material-specific spectroscopic markers, a variety of spacecraft materials frequently utilized in the aerospace industry to construct typical spacecraft were analyzed using reflectance spectroscopy as a characterization technique for assessment on material type according to optical features. This is significant in providing information …
Crack Control And Bond Performance Of Alternative Coated Reinforcements In Concrete,
2022
Clemson University
Crack Control And Bond Performance Of Alternative Coated Reinforcements In Concrete, Sachin Sreedhara
All Dissertations
Concrete cracking in structures is a ubiquitous problem which can lead to the deterioration of the structure. Other than affecting the strength aspect of a structure, cracking impacts the serviceability criteria as well. Although cracking phenomenon in any structure is highly inevitable, it has to be minimized in order to maintain a structure’s life effectively. Cracking in reinforced concrete structures is related to the bond strength developed between the bar and the concrete. It also depends on an ability of the bar to resist the stresses due to shrinkage to minimize the crack. Another important aspect is the resistance offered …
Octopus-Inspired Adhesive Skins For Intelligent
And Rapidly Switchable Underwater Adhesion,
2022
Iowa State University
Octopus-Inspired Adhesive Skins For Intelligent And Rapidly Switchable Underwater Adhesion, Sean T. Frey, A. B. M. Tahidul Haque, Ravi Tutika, Elizabeth V. Krotz, Chanhong Lee, Cole B. Haverkamp, Eric J. Markvicka, Michael D. Bartlett
Department of Mechanical and Materials Engineering: Faculty Publications
The octopus couples controllable adhesives with intricately embedded sensing, processing, and control to manipulate underwater objects. Current synthetic adhesive–based manipulators are typically manually operated without sensing or control and can be slow to activate and release adhesion, which limits system-level manipulation. Here, we couple switchable, octopus-inspired adhesives with embedded sensing, processing, and control for robust underwater manipulation. Adhesion strength is switched over 450× from the ON to OFF state in <50 ms over many cycles with an actively controlled membrane. Systematic design of adhesive geometry enables adherence to nonideal surfaces with low preload and independent control of adhesive strength and adhesive toughness for strong and reliable attachment and easy release. Our bio-inspired nervous system detects objects and autonomously triggers the switchable adhesives. This is implemented into a wearable glove where an array of adhesives and sensors creates a biomimetic adhesive skin to manipulate diverse underwater objects.
A Pilot Study On The Nanoscale Properties Of Bone Tissue Near Lacunae In
Fracturing Women,
2022
University of Nebraska-Lincoln
A Pilot Study On The Nanoscale Properties Of Bone Tissue Near Lacunae In Fracturing Women, Wen Qian, Roman Schmidt, Joseph A. Turner, Sue P. Bare, Joan M. Lappe, Robert R. Recker, Mohammed P. Akhter
Department of Mechanical and Materials Engineering: Faculty Publications
The goal of this study is to investigate the causes of osteoporosis-related skeletal fragility in postmenopausal women. We hypothesize that bone fragility in these individuals is largely due to mineral, and/or intrinsic material properties in the osteocyte lacunar/peri-lacunar regions of bone tissue. Innovative measurements with nanoscale resolution, including scanning electron microscope (SEM), an atomic force microscope that is integrated with infrared spectroscopy (AFM-IR), and nanoindentation, were used to characterize osteocyte lacunar and peri-lacunar properties in bone biopsies from fracturing (Cases) and matched (Age, BMD), non-fracturing (Controls) postmenopausal healthy women. In the peri-lacunar space, the nanoindentation results show that the modulus …
Microfluidic Device For Localized Electroporation,
2022
University of Nebraska-Lincoln
Microfluidic Device For Localized Electroporation, Justin Brooks, Arian Jaberi, Ruiguo Yang
Department of Mechanical and Materials Engineering: Faculty Publications
Electroporation is a common method of transfection due to its relatively low risk and high transfection efficiency. The most common method of electroporation is bulk electroporation which is easily performed on large quantities of cells yet results in variable levels of viability and transfection efficiency across the population. Localized electroporation is an alternative that can be administered on a similar scale but results in much more consistent with higher quality transfection and higher cell viability. This paper discusses the creation and use of a simple and cost-effective device using porous membrane for performing localized electroporation.
Phase Space Analysis Of Nonlinear Wave Propagation In A Bistable
Mechanical Metamaterial With A Defect,
2022
University of Nebraska-Lincoln
Phase Space Analysis Of Nonlinear Wave Propagation In A Bistable Mechanical Metamaterial With A Defect, Mohammed A. Mohammed, Piyush Grover
Department of Mechanical and Materials Engineering: Faculty Publications
We study the dynamics of solitary waves traveling in a one-dimensional chain of bistable elements in the presence of a local inhomogeneity (`defect'). Numerical simulations reveal that depending upon its initial speed, an incoming solitary wave can get transmitted, captured or reflected upon interaction with the defect. The dynamics are dominated by energy exchange between the wave and a breather mode localized at the defect. We derive a reduced-order two degree of freedom Hamiltonian model for wave-breather interaction, and analyze it using dynamical systems techniques. Lobe dynamics analysis reveals the fine structure of phase space that leads to the complicated …
Effect Of Dispersions Of Al2o3 On The Physical And Mechanical Properties Of Pure Copper And Copper-Nickel Alloy,
2022
Future University in Egypt (FUE)
Effect Of Dispersions Of Al2o3 On The Physical And Mechanical Properties Of Pure Copper And Copper-Nickel Alloy, Samah El-Khatib, A. H. Elsayed, A. Y. Shash, A. El-Habak
Future Engineering Journal
This paper illustrates the mechanical and physical properties of pure Cu and Cu-Ni (50-50 wt. %) alloy mixed with Al2O3 (1-4 wt. %) as micro-particles reinforcement materials. The attained composite alloy specimens' characteristics were estimated such as microstructure, relative density, electrical and thermal conductivity, hardness, and compression yield stress properties to adjust the suitable optimum percentage of reinforcing material which has the best physical and mechanical properties with different main matrix materials whether pure Cu powder or Cu-Ni mechanical alloy. The micron-sized Al2O3 was added to enhance the mechanical and physical properties of the …
The Dark Annulus Of A Drop In A Hele-Shaw Cell Is Caused By
The Refraction Of Light Through Its Meniscus,
2022
University of Nebraska-Lincoln
The Dark Annulus Of A Drop In A Hele-Shaw Cell Is Caused By The Refraction Of Light Through Its Meniscus, Sangjin Ryu, Haipeng Zhang, Carson Emeigh
Department of Mechanical and Materials Engineering: Faculty Publications
Knowing the meniscus shape of confined drops is important for understanding how they make first contact and then coalesce. When imaged from the top view by brightfield microscopy, a liquid drop (e.g., corn syrup) confined in a Hele-Shaw cell, surrounded by immiscible liquid (e.g., mineral oil), had a dark annulus, and the width of the annulus decreased with increasing concentration of corn syrup. Since the difference in the annulus width was presumed to be related to the meniscus shape of the drops, three-dimensional images of the drops with different concentrations were obtained using confocal fluorescence microscopy, and their cross-sectional meniscus …
Modular Cable - Driven Surgical
Robots,
2022
Lincoln , NE
Modular Cable - Driven Surgical Robots, Carl A. Nelson, Nicholas Nelson
Department of Mechanical and Materials Engineering: Faculty Publications
A surgical robot can be configured for minimally invasive surgery ( MIS ) and other types of surgery with modular link geometry and disposable components. In some examples, the surgical robot includes a cable driver comprising at least one drive motor configured for tensioning a cable. The surgical robot includes an articulated surgical tool coupled to the drive motor by the cable. The articulated surgical tool comprises at least first and second articulated links and a joint coupling the first and second articulated links. The cable passes through the joint, and the joint comprises an elastic antagonist biased in opposition …
Gross Positioning Device And
Related Systems And Methods,
2022
University of Nebraska - Lincoln
Gross Positioning Device And Related Systems And Methods, Mark A. Reichenbach, Shane M. Farritor
Department of Mechanical and Materials Engineering: Faculty Publications
Disclosed herein are gross positioning systems for use with robotic surgical devices to provide gross positioning of the robotic surgical devices. The gross positioning systems have a base, a first arm link operably coupled to the base, a second arm link operably coupled to the first arm link, a third arm link operably coupled to the second arm link, and a slidable coupling component slidably coupled to the third arm link.
Monolithic Integration Of Hybrid
Perovskite Single Crystals With
Silicon For Highly Sensitive X - Ray
Detectors,
2022
Lincoln , NE
Monolithic Integration Of Hybrid Perovskite Single Crystals With Silicon For Highly Sensitive X - Ray Detectors, Jinsong Huang, Wei Wei
Department of Mechanical and Materials Engineering: Faculty Publications
Perovskite single crystal X - ray radiation detector devices including an X - ray wavelength - responsive active layer including an organolead trihalide perovskite single crystal, a substrate layer comprising an oxide, and a binding layer disposed between the active layer and the substrate layer. The binding layer including a binding molecule having a first functional group that bonds to the organolead trihalide perovskite single crystal and a second functional bonds with the oxide. Inclusion of the binding layer advantageously reduces device noise while retaining signal intensity.
A Review Of Current Construction Guidelines To Inform The Design Of Rammed Earth Houses In Seismically Active Zones,
2022
Technological University Dublin
A Review Of Current Construction Guidelines To Inform The Design Of Rammed Earth Houses In Seismically Active Zones, David Thompson, Charles Augarde, Juan Pablo Osorio
Articles
Sustainability in the materials we use for construction is a prime concern, focusing on reducing the embodied energy and carbon footprints of the materials used. The cement used in concrete products is responsible for a significant proportion of Man's CO2 emissions and its production requires substantial energy input, as do fired clay products. For this reason, products formed from unfired earthen materials are of increasing interest and the current challenges include devising means of robust design for strength and to address durability concerns. One form of earthen construction that employs an in-situ method is rammed earth, and it is a …
Passivation Of Defects In
Perovskite Materials For Improved
Solar Cell Efficiency And Stability,
2022
Lincoln , NE
Passivation Of Defects In Perovskite Materials For Improved Solar Cell Efficiency And Stability, Jinsong Huang, Xiaopeng Zheng
Department of Mechanical and Materials Engineering: Faculty Publications
Semiconductor devices , and methods of forming the same , include a cathode layer , an anode layer , and an active layer disposed between the cathode layer and the anode layer , wherein the active layer includes a perovskite layer . A passivation layer is disposed directly on a surface of the active layer between the cathode layer and the active layer , the passivation layer including a layer of material that passivates both cationic and anionic defects in the surface of the active layer .
Challenges And Signal Processing Of High Strain Rate Mechanical Testing,
2022
Mississippi State University
Challenges And Signal Processing Of High Strain Rate Mechanical Testing, Barae Lamdini
Theses and Dissertations
Dynamic testing provides valuable insight into the behavior of materials undergoing fast deformation. During Split-Hopkinson Pressure Bar testing, stress waves are measured using strain gauges as voltage variations that are usually very small. Therefore, an amplifier is required to amplify the data and analyze it. One of the few available amplifiers designed for this purpose is provided by Vishay Micro-Measurements which limits the user’s options when it comes to research or industry. Among the challenges of implementing the Hopkinson technology in the industry are the size and cost of the amplifier. In this work, we propose a novel design of …
Ultrahigh Strength-High Ductility Combination Low Density Austenitic Steel: Effect Of Aging Temperature And Strain Rate,
2022
The University of Texas at El Paso
Ultrahigh Strength-High Ductility Combination Low Density Austenitic Steel: Effect Of Aging Temperature And Strain Rate, Jaehyun Kim
Open Access Theses & Dissertations
The objective of the study was to optimize the post-thermal treatment of hot rolled Fe-0.92C-26.3Mn-8.79Al-0.05Nb steel. In this regard, the hardness of the experimental steel was studied as a function of aging time and/or strain rate. The study provided an understanding of aging heat treatment for the experimental steel, which was processed by vacuum induction melting, followed by thermo-mechanical rolling involving multiple passes. The rolled steel was subsequently annealed at 900 °C for 4 h followed by water quenching. X-ray diffraction in scanning mode of 2¸=20-100o indicated the presence of austenite structure. In order to study the influence of aging …
Phonon Thermodynamics Of Bcc Zirconium With Machine Learning,
2022
The University of Texas at El Paso
Phonon Thermodynamics Of Bcc Zirconium With Machine Learning, Vanessa Judith Meraz
Open Access Theses & Dissertations
First principles-based simulations have allowed us to explore emerging phenomena in a variety of systems. Its steadfast practicality has led to an increase in molecular and materials design ranging from drug discovery to planetary formation. However ubiquitous in its field, one of its biggest drawbacks is its computational cost, notably so in molecular dynamics simulations. To counter this setback, there have been many leading efforts in machine learning methods, whether it be in algorithms or network architectures. Our contribution uses an active learning algorithm paired with a tensor field network, e3nn. By steadily feeding new data points to our model, …
Suitability Of Low-Cost Additive Manufacturing For Polymer Electrolyte Fuel Cells,
2022
The University of Texas at El Paso
Suitability Of Low-Cost Additive Manufacturing For Polymer Electrolyte Fuel Cells, David Alexander
Open Access Theses & Dissertations
The purpose of this dissertation is to study the feasibility of low-cost additive manufacturing to fabricate polymer electrolyte fuel cell bipolar plate materials. Traditional manufacturing techniques include molding, milling, hollow embossing, hydro-forming, rolling, and electromagnetic forming. These processes are employed when a design has been selected due to higher costs at low volumes. The combination of high initial costs and bipolar plates being the most expensive component of the polymer electrolyte fuel cell creates incentive to mitigate this obstacle. The feasibility of low-cost additive manufactured bipolar plates will be proven by fabrication, post-processing, and characterization of printed test specimen. The …
