Engineering Commons^™

Correlative Imaging Of Three-Dimensional Cell Culture On Opaque Bioscaffolds For Tissue Engineering Applications, Mone’T Sawyer, Josh Eixenberger, Olivia Nielson, Jacob Manzi, Cadré Francis, Raquel Montenegro-Brown, Harish Subbaraman, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

Three-dimensional (3D) tissue engineering (TE) is a prospective treatment that can be used to restore or replace damaged musculoskeletal tissues, such as articular cartilage. However, current challenges in TE include identifying materials that are biocompatible and have properties that closely match the mechanical properties and cellular microenvironment of the target tissue. Visualization and analysis of potential 3D porous scaffolds as well as the associated cell growth and proliferation characteristics present additional problems. This is particularly challenging for opaque scaffolds using standard optical imaging techniques. Here, we use graphene foam (GF) as a 3D porous biocompatible substrate, which is scalable, reproducible, …

Synergic Antitumor Effect Of Photodynamic Therapy And Chemotherapy Mediated By Nano Drug Delivery Systems, Mozhgan Aghajanzadeh, Mostafa Zamani, Fereshteh Rajabi Kouchi, Josh Eixenberger, Dorsa Shirini, David Estrada, Farhad Shirini

Materials Science and Engineering Faculty Publications and Presentations

This review provides a summary of recent progress in the development of different nano-platforms for the efficient synergistic effect between photodynamic therapy and chemotherapy. In particular, this review focuses on various methods in which photosensitizers and chemotherapeutic agents are co-delivered to the targeted tumor site. In many cases, the photosensitizers act as drug carriers, but this review, also covers different types of appropriate nanocarriers that aid in the delivery of photosensitizers to the tumor site. These nanocarriers include transition metal, silica and graphene-based materials, liposomes, dendrimers, polymers, metal–organic frameworks, nano emulsions, and biologically derived nanocarriers. Many studies have demonstrated various …

First-Principles Studies Of Mof Absorption On Hydroxylated And Non-Hydroxylated Metal Oxide Surfaces And Implications For Atomic Layer Deposition Of Mos2, Matthew Lawson, Elton Graugnard, Lan Li

Materials Science and Engineering Faculty Publications and Presentations

Significant interest in two-dimensional transition metal dichalcogenides has led to numerous experimental studies of their synthesis using scalable vapor phase methods, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). ALD typically allows lower deposition temperatures, and nucleation of chemical precursors requires reactions with surface functional groups. A common first-principles method used to study ALD modeling is the calculation of activation energy for a proposed reaction pathway. In this work we calculated the partial charge densities, local density of states (LDoS), Bader charge analysis, adsorption energies, and charge density difference using density functional theory (DFT) to investigate the …

High-Performance Flexible Bismuth Telluride Thin Film From Solution Processed Colloidal Nanoplates, Madhusudan Kongara, Tony Varghese, Karthik Chinnathambi, Jesse Schimpf, Josh Eixenberger, Paul H. Davis, Yaqiao Wu, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

Thermoelectric generators are an environmentally friendly and reliable solid‐state energy conversion technology. Flexible and low‐cost thermoelectric generators are especially suited to power flexible electronics and sensors using body heat or other ambient heat sources. Bismuth telluride (Bi₂Te₃) based thermoelectric materials exhibit their best performance near room temperature making them an ideal candidate to power wearable electronics and sensors using body heat. In this report, Bi₂Te₃ thin films are deposited on a flexible polyimide substrate using low‐cost and scalable manufacturing methods. The synthesized Bi₂Te₃ nanocrystals have a thickness of 35 ± …

Mechanochemical Conversion Kinetics Of Red To Black Phosphorus And Scaling Parameters For High Volume Synthesis, Samuel V. Pedersen, Florent Muramutsa, Joshua D. Wood, Chad Husko, David Estrada, Brian J. Jaques

Materials Science and Engineering Faculty Publications and Presentations

Adopting black phosphorus (BP) as a material in electronic and optoelectronic device manufacturing requires the development and understanding of a large-scale synthesis technique. To that end, high-energy planetary ball milling is demonstrated as a scalable synthesis route, and the mechanisms and conversion kinetics of the BP phase transformation are investigated. During the milling process, media collisions rapidly compress amorphous red phosphorus (RP) into crystalline, orthorhombic BP flakes, resulting in a conversion yield of ≈90% for ≈5 g of bulk BP powder. Milling conversion kinetics, monitored via ex situ x-ray diffraction, manifest a sigmoidal behavior best described by the Avrami rate …

A Review Of Inkjet Printed Graphene And Carbon Nanotubes Based Gas Sensors, Twinkle Pandhi, Ashita Chandnani, Harish Subbaraman, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

Graphene and carbon nanotube (CNT)-based gas/vapor sensors have gained much traction for numerous applications over the last decade due to their excellent sensing performance at ambient conditions. Inkjet printing various forms of graphene (reduced graphene oxide or modified graphene) and CNT (single-wall nanotubes (SWNTs) or multiwall nanotubes (MWNTs)) nanomaterials allows fabrication onto flexible substrates which enable gas sensing applications in flexible electronics. This review focuses on their recent developments and provides an overview of the state-of-the-art in inkjet printing of graphene and CNT based sensors targeting gases, such as NO₂, Cl₂, CO₂, NH_{3 …}

Emerging Gene-Editing Modalities For Osteoarthritis, Alekya S. Tanikella, Makenna J. Hardy, Stephanie M. Frahs, Aidan G. Cormier, Kalin D. Gibbons, Clare K. Fitzpatrick, Julia Thom Oxford

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Osteoarthritis (OA) is a pathological degenerative condition of the joints that is widely prevalent worldwide, resulting in significant pain, disability, and impaired quality of life. The diverse etiology and pathogenesis of OA can explain the paucity of viable preventive and disease-modifying strategies to counter it. Advances in genome-editing techniques may improve disease-modifying solutions by addressing inherited predisposing risk factors and the activity of inflammatory modulators. Recent progress on technologies such as CRISPR/Cas9 and cell-based genome-editing therapies targeting the genetic and epigenetic alternations in OA offer promising avenues for early diagnosis and the development of personalized therapies. The purpose of this …

A Cathode Support Structure For Use In A Magnetron Oscillator Experiment, Daylon Black, Ryan Harper, Patrick Ward, Jacob Davlin, Omar Bentancourt, Donald Plumlee, Jim Browning

Electrical and Computer Engineering Faculty Publications and Presentations

A Low Temperature Cofired Ceramic (LTCC) material system has been used to develop a protype field emission cathode structure for use in an experimental magnetron oscillator. The structure is designed for used with 30 Gated Field Emission Array (GFEA) die electrically connected through silver metal traces and electrical vias. To approximate a cylinder, the cathode structure (48 mm long and 13.7 mm in diameter) is comprised of 10 faceted plates which cover the GFEA dies. Slits in the facet plates allow electron injection. The GFEA die (3 mm x 8 mm) are placed in axial columns of 3 and spaced …

A Parametric Study For In-Pile Use Of The Thermal Conductivity Needle Probe Using A Transient, Multilayered Analytical Model, Courtney Hollar, Austin Fleming, Kurt Davis, Ralph Budwig, Colby Jensen, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

By utilizing an in-pile measurement, thermal conductivity can be determined under prototypic conditions over a range of burnup. In this work we develop a multilayer quadrupoles analytical model to describe the transient thermal interactions between a line heat source (i.e. needle probe) and cylindrical nuclear fuel geometry for inpile thermal conductivity measurements. A finite element analysis of the detailed needle probe geometry was compared to results from the analytical model to verify the assumptions made in the analytical model. Experimentally, the needle probe was used to measure the thermal properties of polytetrafluoroethylene (PTFE) and stainless steel 304 with three different …

Simulation Of A Time-Varying Distributed Cathode In A Linear Format Crossed-Field Amplifier, Marcus Pearlman, Jim Browning

Electrical and Computer Engineering Faculty Publications and Presentations

The effects of a temporally modulated, distributed cathode in a linear format crossed-field amplifier (CFA) are simulated in VSim and analyzed. A linear format, 150 MHz, low power (100 W), moderate gain (7 dB), meander line CFA is used as the basis for the simulation model. This paper describes simulations with different time-varying distributed cathodes in which electron injection is modulated at the RF frequency both in and out of phase with the RF input. At low RF input power the modulated electron injection dominates the operation. Injecting in phase with the RF input shows gain increases from 23 dB …

Work In Progress: Mastery-Based Grading In An Introduction To Circuits Class, Noah Salzman, Kurtis D. Cantley, Gary L. Hunt

Electrical and Computer Engineering Faculty Publications and Presentations

Circuits is often the first required course in an electrical engineering curriculum that demands application of multiple concepts from prerequisite math and physics courses. This integration of knowledge can be a challenge for many students. Effective teaching methods can enhance the overall learning experience, increase program retention, and improve student understanding of foundational topics in electrical engineering. This paper outlines a mastery-based grading structure implemented in a sophomore-level circuits class. The focus is placed at this level because the course is a critical prerequisite for many other courses in the electrical and computer engineering (ECE) curriculum. The knowledge that students …

Thermal Transport In Layer-By-Layer Assembled Polycrystalline Graphene Films, David Estrada, Alondra Perez

Materials Science and Engineering Faculty Publications and Presentations

New technologies are emerging which allow us to manipulate and assemble 2-dimensional (2D) building blocks, such as graphene, into synthetic van der Waals (vdW) solids. Assembly of such vdW solids has enabled novel electronic devices and could lead to control over anisotropic thermal properties through tuning of inter-layer coupling and phonon scattering. Here we report the systematic control of heat flow in graphene-based vdW solids assembled in a layer-by-layer (LBL) fashion. In-plane thermal measurements (between 100 K and 400 K) reveal substrate and grain boundary scattering limit thermal transport in vdW solids composed of one to four transferred layers of …

Corrosion Initiation And Propagation On Carburized Martensitic Stainless Steel Surfaces Studied Via Advanced Scanning Probe Microscopy, Armen Kvryan, Corey M. Efaw, Kari A. Higginbotham, Olivia O. Maryon, Paul H. Davis, Elton Graugnard, Michael F. Hurley

Materials Science and Engineering Faculty Publications and Presentations

Historically, high carbon steels have been used in mechanical applications because their high surface hardness contributes to excellent wear performance. However, in aggressive environments, current bearing steels exhibit insufficient corrosion resistance. Martensitic stainless steels are attractive for bearing applications due to their high corrosion resistance and ability to be surface hardened via carburizing heat treatments. Here three different carburizing heat treatments were applied to UNS S42670: a high-temperature temper (HTT), a low-temperature temper (LTT), and carbo-nitriding (CN). Magnetic force microscopy showed differences in magnetic domains between the matrix and carbides, while scanning Kelvin probe force microscopy (SKPFM) revealed a 90–200 …

Open-Source Automated Chemical Vapor Deposition System For The Production Of Two-Dimensional Nanomaterials, Lizandra Williams-Godwin, Dale Brown, Richard Livingston, Tyler Webb, Lynn Karriem, Elton Graugnard, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

The study of two- dimensional (2D) materials is a rapidly growing area within nanomaterials research. However, the high equipment costs, which include the processing systems necessary for creating these materials, can be a barrier to entry for some researchers interested in studying these novel materials. Such process systems include those used for chemical vapor deposition, a preferred method for making these materials. To address this challenge, this article presents the first open-source design for an automated chemical vapor deposition system that can be built for less than a third of the cost for a comparable commercial system. The materials and …

Toward Improving Ambient Volta Potential Measurements With Skpfm For Corrosion Studies, Corey M. Efaw, Thiago Da Silva, Paul H. Davis, Lan Li, Elton Graugnard, Michael F. Hurley

Materials Science and Engineering Faculty Publications and Presentations

Scanning Kelvin probe force microscopy (SKPFM) is used in corrosion studies to quantify the relative nobility of different microstructural features present within complex metallic systems and thereby elucidate possible corrosion initiation sites. However, Volta potential differences (VPDs) measured via SKPFM in the literature for metal alloys exhibit large variability, making interpretation and application for corrosion studies difficult. We have developed an improved method for referencing SKPFM VPDs by quantifying the closely related work function of the probe relative to an inert gold standard whose modified work function is calculated via density functional theory (DFT). By measuring and tracking changes in …

A Spatiotemporal Pattern Detector, Robert Ivans, Kurtis D. Cantley

Electrical and Computer Engineering Faculty Publications and Presentations

A spatiotemporal pattern detector design is presented which can identify three fundamental spatiotemporal patterns consisting of two spikes (from different neurons or from the same neuron). These fundamental cases provide the building blocks for construction of more complicated arbitrary spatiotemporal patterns. The overall design consists of three primary subcircuits, and the operation of each is described. The detection of the three cases of spatiotemporal patterns, and the detection of a more complicated pattern by a network of Spatiotemporal Pattern Detectors, is then demonstrated through simulation using the Cadence Virtuoso platform.

Learning Behavior Of Memristor-Based Neuromorphic Circuits In The Presence Of Radiation, Sumedha Gandharava Dahl, Robert C. Ivans, Kurtis D. Cantley

Electrical and Computer Engineering Faculty Publications and Presentations

In this paper, a feed-forward spiking neural network with memristive synapses is designed to learn a spatio-temporal pattern representing the 25-pixel character ‘B’ by separating correlated and uncorrelated afferents. The network uses spike-timing-dependent plasticity (STDP) learning behavior, which is implemented using biphasic neuron spikes. A TiO₂ memristor non-linear drift model is used to simulate synaptic behavior in the neuromorphic circuit. The network uses a many-to-one topology with 25 pre-synaptic neurons (afferent) each connected to a memristive synapse and one post-synaptic neuron. The memristor model is modified to include the experimentally observed effect of state-altering radiation. During the learning process, …

Recovery Of Stem Cell Proliferation By Low Intensity Vibration Under Simulated Microgravity Requires Linc Complex, H. Touchstone, R. Bryd, S. Loisate, M. Thompson, X. Pu, R. Beard, J. T. Oxford, G. Uzer

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Mesenchymal stem cells (MSC) rely on their ability to integrate physical and spatial signals at load bearing sites to replace and renew musculoskeletal tissues. Designed to mimic unloading experienced during spaceflight, preclinical unloading and simulated microgravity models show that alteration of gravitational loading limits proliferative activity of stem cells. Emerging evidence indicates that this loss of proliferation may be linked to loss of cellular cytoskeleton and contractility. Low intensity vibration (LIV) is an exercise mimetic that promotes proliferation and differentiation of MSCs by enhancing cell structure. Here, we asked whether application of LIV could restore the reduced proliferative capacity seen …

Boron-Implanted Silicon Substrates For Physical Adsorption Of Dna Origami, Sadao Takabayashi, Shohei Kotani, Juan Flores-Estrada, Elijah Spears, Jennifer E. Padilla, Lizandra C. Godwin, Elton Graugnard, Wan Kuang, William L. Hughes

Materials Science and Engineering Faculty Publications and Presentations

DNA nanostructures routinely self-assemble with sub-10 nm feature sizes. This capability has created industry interest in using DNA as a lithographic mask, yet with few exceptions, solution-based deposition of DNA nanostructures has remained primarily academic to date. En route to controlled adsorption of DNA patterns onto manufactured substrates, deposition and placement of DNA origami has been demonstrated on chemically functionalized silicon substrates. While compelling, chemical functionalization adds fabrication complexity that limits mask efficiency and hence industry adoption. As an alternative, we developed an ion implantation process that tailors the surface potential of silicon substrates to facilitate adsorption of DNA nanostructures …

Introducing The Boise State Bangla Handwriting Dataset And An Efficient Offline Recognizer Of Isolated Bangla Characters, Nishatul Majid, Elisa H. Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

This introduces the Boise State Bangla Handwriting Dataset, a publicly accessible offline handwriting dataset of Bangla script. This can be found at https://scholarworks.boisestate.edu/saipl/1/

A basic character recognition method is presented where the features are extracted based on zonal pixel counts, structural strokes and grid points with U-SURF descriptors modeled with bag of features.

Benchmarking with this approach on 3 other publicly available Bangla datasets is reported. The highest classification accuracy obtained with an SVM classifier based on a cubic kernel is 96.8%.

De-Risking Transdisciplinary Research By Creating Shared Values, Donna C. Llewellyn, William L. Hughes

Materials Science and Engineering Faculty Publications and Presentations

This Lessons Learned Paper describes a yearlong faculty development pilot program that was designed to help a team of faculty de-risk their pursuit of wicked research problems. Wicked problems are extraordinarily difficult to solve due to their incomplete, contradictory, and at times changing requirements. They often include multiple stakeholders with competing interests and worldviews. As a result, they are risky by definition because they are difficult to fund, publish, and collaborate on. Presented here, a team of eleven faculty, from six different academic units, explored their personal and professional values during an initial off-site two and a half day retreat. …

Introducing The Xxx Bangla Handwriting Dataset And An Efficient Offline Recognizer Of Isolated Bangla Characters, Nishatul Majid, Elisa H. Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents a publicly accessible Bangla offline handwriting dataset, as well as benchmarking with a simple and robust isolated handwritten character recognition scheme. The dataset is named XXX Bangla Handwriting Dataset. The dataset contains 2 pages. The first has a 104 word/364 character essay. The essay uses 49 basic characters, all 11 vowel diacritics and 32 high frequency consonant conjuncts. The second page contains 84 isolated units containing all basic characters, numbers, vowel diacritics and several high frequency conjuncts. The initial release is based on the voluntary contribution of 100 different writers. One of the highlights and unique features …

Improving The Relative Calculations Of Volta Potential Differences Acquired From Scanning Kelvin Probe Force Microscopy (Skpfm) From Comparing An Inert Material To First-Principle Calculations, C. M. Efaw, T. Da Silva, P. H. Davis, L. Li, E. Graugnard, M. Hurley

Materials Science and Engineering Faculty Publications and Presentations

An improved relative scaling of Volta potential differences (VPD) acquired from scanning Kelvin probe force microscopy (SKPFM) was developed by quantifying the probe work function. In corrosion studies, SKPFM has been used to identify local nobility of complex metallic systems and provide theoretical corrosion initiation sites. However, large variability in measured VPD values for metallic phases has led to controversy in their interpretation. Tracking changes of the probe work function has been shown to decrease the variability seen in SKPFM results. To quantify the work function of SKPFM probes, the measured VPD of an inert gold standard was compared to …

Detection Of Methylation On Dsdna Using Nanopores In Mos2 Membrane, David Estrada

Materials Science and Engineering Faculty Publications and Presentations

Methylation at the 5-carbon position of the cytosine nucleotide base in DNA has been shown to be a reliable diagnostic biomarker for carcinogenesis. Early detection of methylation and intervention could drastically increase the effectiveness of therapy and reduce the cancer mortality rate. Current methods for detecting methylation involve bisulfite genomic sequencing, which are cumbersome and demand a large sample size of bodily fluids to yield accurate results. Hence, more efficient and cost effective methods are desired. Based on our previous work, we present a novel nanopore-based assay using a nanopore in a MoS₂ membrane, and the methyl-binding protein (MBP), …

Phase Separation In Ti-6al-4v Alloys With Boron Additions For Biomedical Applications: Scanning Kelvin Probe Force Microscopy Investigation Of Microgalvanic Couples And Corrosion Initiation, P. H. Davis, K. Robles, K. Livingston, S. Johns, V. A. Ravi, E. Graugnard, M. F. Hurley

Materials Science and Engineering Faculty Publications and Presentations

To investigate the effect of boron additions on the corrosion behavior of Ti-6Al-4V for potential use in biomedical implants and devices, cast samples of Ti-6Al-4V were alloyed with 0.01% to 1.09% boron by weight and subjected to hot isostatic pressing. Subsequent analysis via scanning Kelvin probe force microscopy and scanning electron microscopy/energy-dispersive spectroscopy revealed the presence of both alpha (α) and beta (β) phase titanium, enriched in aluminum and vanadium, respectively. At all concentrations, boron additions affected the grain structure and were dispersed throughout both phases, but above the solubility limit, needle-like TiB structures also formed. …

Vertically Integrated Projects (Vip) Programs: Multidisciplinary Projects With Homes In Any Discipline, Jocelyn B. S. Cullers, William L. Hughes, Donna C. Llewellyn

Materials Science and Engineering Faculty Publications and Presentations

A survey of papers in the ASEE Multidisciplinary Engineering Division over the last three years shows three main areas of emphasis: individual courses; profiles of specific projects; and capstone design courses. However, propagating multidisciplinary education across the vast majority of disciplines offered at educational institutions with varying missions requires models that are independent of the disciplines, programs, and institutions in which they were originally conceived. Further, models that can propagate must be cost effective, scalable, and engage and benefit participating faculty. Since 2015, a consortium of twenty-four institutions has come together around one such model, the Vertically Integrated Projects (VIP) …

Spatio-Temporal Pattern Recognition In Neural Circuits With Memory-Transistor-Driven Memristive Synapses, Kurtis D. Cantley, Robert C. Ivans, Anand Subramaniam, Eric M. Vogel

Electrical and Computer Engineering Faculty Publications and Presentations

Spiking neural circuits have been designed in which the memristive synapses exhibit spike timing-dependent plasticity (STDP). STDP is a learning mechanism where synaptic weight (the strength of the connection between two neurons) depends on the timing of pre-and post-synaptic action potentials. A known capability of networks with STDP is detection of simultaneously recurring patterns within the population of afferent neurons. This work uses SPICE (simulation program with integrated circuit emphasis) to demonstrate the spatio-temporal pattern recognition (STPR) effect in networks with 25 afferent neurons. The neuron circuits are the leaky integrate-and-fire (I&F) type and implemented using extensively validated ambipolar nano-crystalline …

A Cmos Synapse Design Implementing Tunable Asymmetric Spike Timing-Dependent Plasticity, Robert C. Ivans, Kurtis D. Cantley, Justin L. Shumaker

Electrical and Computer Engineering Faculty Publications and Presentations

A CMOS synapse design is presented which can perform tunable asymmetric spike timing-dependent learning in asynchronous spiking neural networks. The overall design consists of three primary subcircuit blocks, and the operation of each is described. Pair-based Spike Timing-Dependent Plasticity (STDP) of the entire synapse is then demonstrated through simulation using the Cadence Virtuoso platform. Tuning of the STDP curve learning window and rate of synaptic weight change is possible using various control parameters. With appropriate settings, it is shown the resulting learning rule closely matches that observed in biological systems.

Pulse Shape And Timing Dependence On The Spike-Timing Dependent Plasticity Response Of Ion-Conducting Memristors As Synapses, Kris A. Campbell, Kolton T. Drake, Elisa H. Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

Ion-conducting memristors comprised of the layered materials Ge₂Se₃/SnSe/Ag are promising candidates for neuromorphic computing applications. Here, the spike-timing dependent plasticity (STDP) application is demonstrated for the first time with a single memristor type operating as a synapse over a timescale of 10 orders of magnitude, from nanoseconds through seconds. This large dynamic range allows the memristors to be useful in applications that require slow biological times, as well as fast times such as needed in neuromorphic computing, thus allowing multiple functions in one design for one memristor type—a “one size fits all” approach. This work also …

A Validated Software Application To Measure Fiber Organization In Soft Tissue, Erica E. Morrill, Azamat N. Tulepbergenov, Christina J. Stender, Roshani Lamichhane, Raquel J. Brown, Trevor J. Lujan

Mechanical and Biomedical Engineering Faculty Publications and Presentations

The mechanical behavior of soft connective tissue is governed by a dense network of fibrillar proteins in the extracellular matrix. Characterization of this fibrous network requires the accurate extraction of descriptive structural parameters from imaging data, including fiber dispersion and mean fiber orientation. Common methods to quantify fiber parameters include fast Fourier transforms (FFT) and structure tensors, however, information is limited on the accuracy of these methods. In this study, we compared these two methods using test images of fiber networks with varying topology. The FFT method with a band-pass filter was the most accurate, with an error of 0.71 …