Engineering Commons^™

Anomalous Stranski-Krastanov Growth Of (111)-Oriented Quantum Dots With Tunable Wetting Layer Thickness, Christopher F. Schuck, Simon K. Roy, Trent Garrett, Paul J. Simmonds

Materials Science and Engineering Faculty Publications and Presentations

Driven by tensile strain, GaAs quantum dots (QDs) self-assemble on In_0.52Al_0.48As(111)A surfaces lattice-matched to InP substrates. In this study, we show that the tensile-strained self-assembly process for these GaAs(111)A QDs unexpectedly deviates from the well-known Stranski-Krastanov (SK) growth mode. Traditionally, QDs formed via the SK growth mode form on top of a flat wetting layer (WL) whose thickness is fixed. The inability to tune WL thickness has inhibited researchers’ attempts to fully control QD-WL interactions in these hybrid 0D-2D quantum systems. In contrast, using microscopy, spectroscopy, and computational modeling, we demonstrate that for GaAs(111)A QDs, we …

Normalization Of Unconstrained Handwritten Words In Terms Of Slope And Slant Correction, Suman Kumar Bera, Akash Chakrabarti, Sagnik Lahiri, Elisa H. Barney Smith, Ram Sarkar

Electrical and Computer Engineering Faculty Publications and Presentations

In offline handwritten text slope (or skew) and slant are inevitably introduced, but to varying degrees depending on several factors, such as the writing style, speed and mood of the writers. Therefore slope and slant detection in offline handwritten text and their subsequent correction have become the critical preprocessing steps for document analysis and retrieval systems to neutralize the variability of writing styles and to improve the performance of word and character recognition systems. In this paper, we present new methods that use two novel core-region detection techniques to estimate both the slope and slant angles of offline handwritten word …

Machine Learning Predictions Electronic Couplings For Charge Transport Calculations Of P3ht, Evan D. Miller, Matthew L. Jones, Mike M. Henry, Bryan Stanfill, Eric Jankowski

Materials Science and Engineering Faculty Publications and Presentations

The purpose of this work is to lower the computational cost of predicting charge mobilities in organic semiconductors, which will benefit the screening of candidates for inexpensive solar power generation. We characterize efforts to minimize the number of expensive quantum chemical calculations we perform by training machines to predict electronic couplings between monomers of poly-(3-hexylthiophene). We test five machine learning techniques and identify random forests as the most accurate, information-dense, and easy-to-implement approach for this problem, achieving mean-absolute-error of 0.02 [× 1.6 × 10⁻¹⁹ J], R² = 0.986, predicting electronic couplings 390 times faster than quantum chemical calculations, …

Characterization Of Zirconium Oxides Part I: Raman Mapping And Spectral Feature Analysis, Corey M. Efaw, Jordan L. Vandegrift, Michael Reynolds, Samuel Mcmurdie, Brian J. Jaques, Hui Xiong, Michael F. Hurley

Materials Science and Engineering Faculty Publications and Presentations

Raman mapping of sectioned zirconium cladding oxides was performed to analyze different spectral features before and after breakaway, as well as between zirconium and its alloys Zr-2.65Nb, Zry-3, and Zry-4. Oxide phase composition, or percent tetragonality, was defined to compare tetragonal to monoclinic zirconia. Percent tetragonality was spatially mapped to support distinction of zirconia phase distribution. A tetragonal-rich layer was seen at the metal/oxide interface, while post-breakaway samples exhibited increased amount of tetragonal phase in the bulk of their oxides. Spatial mapping of spectral peak location and half-width at half-maximum was accomplished to distinguish differences in stability mechanisms of tetragonal-rich …

Oxidation Behavior Of Welded Zry-3, Zry-4, And Zr–1nb Tubes, Jordan Vandegrift, Clemente J. Parga, Ben Coryell, Darryl P. Butt, Brian J. Jaques

Materials Science and Engineering Faculty Publications and Presentations

The Transient Reactor Test (TREAT) facility is a research reactor designed to simulate rapid transients to test new fuel designs. TREAT's cladding is exposed to unique conditions compared to normal water reactors. These conditions include: exposure to air at high temperatures (≥600 °C), rapid heating (≈700 °^C/_s), and cladding geometry that includes chamfers and welds. This work investigates the effects of chamfering and welding on the oxidation behavior of zirconium alloys (Zircaloy-3, Zircaloy-4, and Zr–1Nb). Tube specimens were examined under isothermal and transient conditions in dry and humid air. The effect of weld type (tungsten inert …

Inas(111)A Homoepitaxy With Molecular Beam Epitaxy, Kevin D. Vallejo, Trent A. Garrett, Kathryn E. Sautter, Kevin Saythavy, Baolai Liang, Paul J. Simmonds

Materials Science and Engineering Faculty Publications and Presentations

The authors have established a robust set of growth conditions for homoepitaxy of high-quality InAs with a (111)A crystallographic orientation by molecular beam epitaxy (MBE). By tuning the substrate temperature, the authors obtain a transition from a 2D island growth mode to step-flow growth. Optimized MBE parameters (substrate temperature = 500 °C, growth rate = 0.12ML/s, and V/III ratio ≥ 40) lead to the growth of extremely smooth InAs(111)A films, free from hillocks and other 3D surface imperfections. The authors see a correlation between InAs surface smoothness and optical quality, as measured by photoluminescence spectroscopy. This work establishes InAs(111)A as …

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 …

Kinetics Of Silver Photodiffusion Into Amorphous S-Rich Germanium Sulphide – Neutron And Optical Reflectivity, Yoshifumi Sakaguchi, Hidehito Asaoka, Maria Mitkova

Electrical and Computer Engineering Faculty Publications and Presentations

Silver photodiffusion is one of the attractive photo-induced changes observed in amorphous chalcogenides. In this research, we focus on amorphous S-rich germanium sulphide and study the kinetics of the silver photodiffusion by neutron reflectivity, as well as optical reflectivity. It was found from the neutron reflectivity profiles with 30 s time resolution that silver dissolved into the germanium sulphide layer, forming a metastable reaction layer between the Ag and the germanium sulphide layers, within 2 min of light exposure. Subsequently, silver slowly diffused from the metastable reaction layer to the germanium sulphide host layer until the Ag concentration in both …

Utilizing A Single Silica Nanospring As An Insulating Support To Characterize The Electrical Transport And Morphology Of Nanocrystalline Graphite, David Estrada, Paul H. Davis, Twinkle Pandhi

Materials Science and Engineering Faculty Publications and Presentations

A graphitic carbon, referred to as graphite from the University of Idaho thermolyzed asphalt reaction (GUITAR), was coated in silica nanosprings and silicon substrates via the pyrolysis of commercial roofing tar at 800 °C in an inert atmosphere. Scanning electron microscopy and transmission electron microscopy images indicate that GUITAR is an agglomeration of carbon nanospheres formed by the accretion of graphitic flakes into a ~100 nm layer. Raman spectroscopic analyses, in conjunction with scanning electron microscopy and transmission electron microscopy, indicate that GUITAR has a nanocrystalline structure consisting of ~1–5 nm graphitic flakes interconnected by amorphous sp³ bonded carbon. …

Heat Wave Intensity Duration Frequency Curve: A Multivariate Approach For Hazard And Attribution Analysis, Omid Mazdiyasni, Mojtaba Sadegh, Felicia Chiang, Amir Aghakouchak

Civil Engineering Faculty Publications and Presentations

Atmospheric warming is projected to intensify heat wave events, as quantified by multiple descriptors, including intensity, duration, and frequency. While most studies investigate one feature at a time, heat wave characteristics are often interdependent and ignoring the relationships between them can lead to substantial biases in frequency (hazard) analyses. We propose a multivariate approach to construct heat wave intensity, duration, frequency (HIDF) curves, which enables the concurrent analysis of all heat wave properties. Here we show how HIDF curves can be used in various locations to quantitatively describe the likelihood of heat waves with different intensities and durations. We then …

A Simple Method To Characterize High Rate Twin Boundary Kinetics In Ni-Mn-Ga, Bibek Karki, Peter Müllner

Materials Science and Engineering Faculty Publications and Presentations

Experimental characterization of twin boundary kinetics is essential to systematically test and reproduce the actuation properties of Magnetic Shape Memory (MSM) elements at high rates. Here, we present a simple, nondestructive, experimental method to quantify the dynamic response of an MSM crystal and extract the major material properties that govern its kinetics. The tested sample is subjected to a mechanical pulse that is produced by a simple off-the-shelf solenoid. The mechanical pulse leads to actuation of the tested MSM Ni–Mn–Ga single crystal within 10 ms, during which the twin boundary velocity varies between zero and 2 m/s. The displacement and …

Comparison Of The Electrical Response Of Cu And Ag Ion-Conducting Sdc Memristors Over The Temperature Range 6 K To 300 K, Kolton Drake, Tonglin Lu, Md. Kamrul H. Majumdar, Kristy A. Campbell

Electrical and Computer Engineering Faculty Publications and Presentations

Electrical performance of self-directed channel (SDC) ion-conducting memristors which use Ag and Cu as the mobile ion source are compared over the temperature range of 6 K to 300 K. The Cu-based SDC memristors operate at temperatures as low as 6 K, whereas Ag-based SDC memristors are damaged if operated below 125 K. It is also observed that Cu reversibly diffuses into the active Ge₂Se₃ layer during normal device shelf-life, thus changing the state of a Cu-based memristor over time. This was not observed for the Ag-based SDC devices. The response of each device type to sinusoidal …

Elementary School Student Development Of Stem Attitudes And Perceived Learning In A Stem Integrated Robotics Curriculum, Yu-Hui Ching, Dazhi Yang, Sasha Wang, Youngkyun Baek, Steve Swanson, Bhaskar Chittoori

Educational Technology Faculty Publications and Presentations

Robotics has been advocated as an emerging approach to engaging K-12 students in learning science, technology, engineering, and mathematics (STEM). This study examined the impacts of a project-based STEM integrated robotics curriculum on elementary school students’ attitudes toward STEM and perceived learning in an afterschool setting. Three elementary school teachers and 18 fourth to sixth graders participated in an eight-week-long program. Quantitative and qualitative data were collected and analyzed, and showed students’ attitudes toward math improved significantly at the end of the robotics curriculum. Three specific areas of learning were identified, including STEM content learning and connection, engagement and perseverance, …

Implementing Population-Based Mass Drug Administration For Malaria: Experience From A High Transmission Setting In North Eastern Uganda, Richard Elliott

Materials Science and Engineering Faculty Publications and Presentations

Background: Mass drug administration (MDA) is a suggested mean to accelerate efforts towards elimination and attainment of malaria-free status. There is limited evidence of suitable methods of implementing MDA programme to achieve a high coverage and compliance in low-income countries. The objective of this paper is to assess the impact of this MDA delivery strategy while using coverage measured as effective population in the community and population available.

Methods: Population-based MDA was implemented as a part of a larger program in a high transmission setting in Uganda. Four rounds of interventions were implemented over a period of 2 years at …

Oxidation Behavior Of Zirconium, Zircaloy-3, Zircaloy-4, Zr-1nb, And Zr- 2.5nb In Air And Oxygen, Jordan L. Vandegrift, Patrick M. Price, John-Paul Stroud, Clemente J. Parga, Isabella J. Van Rooyen, Brian J. Jaques, Darryl P. Butt

Materials Science and Engineering Faculty Publications and Presentations

The Transient Reactor Test (TREAT) facility at the Idaho National Laboratory currently utilizes a legacy Zircaloy- 3 cladding, which is no longer commercially available. TREAT is air cooled and routinely operates at temperatures well above that of traditional reactor designs. This study investigates the oxidation behavior of pure zirconium and its alloys (Zircaloy-3, Zircaloy-4, Zr-1Nb, Zr-2.5Nb) in Ar+20%O₂ and N₂+20%O₂ atmospheres at temperatures ranging from 400–800 °C to determine which alloy should be implemented as TREAT's cladding. While the oxidation behavior of zirconium based cladding materials has been extensively documented, this study focuses on direct comparison …

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 …

Reinforcement Learning For Self Organization And Power Control Of Two-Tier Heterogeneous Networks, Roohollah Amiri, Mojtaba Ahmadi Almasi, Jeffrey G. Andrews, Hani Mehrpouyan

Electrical and Computer Engineering Faculty Publications and Presentations

Self-organizing networks (SONs) can help manage the severe interference in dense heterogeneous networks (HetNets). Given their need to automatically configure power and other settings, machine learning is a promising tool for data-driven decision making in SONs. In this paper, a HetNet is modeled as a dense two-tier network with conventional macrocells overlaid with denser small cells (e.g. femto or pico cells). First, a distributed framework based on multi-agent Markov decision process is proposed that models the power optimization problem in the network. Second, we present a systematic approach for designing a reward function based on the optimization problem. Third, we …

Teaching The Hardware Implementation Of Cybesecurity Encryption Algorithms On Fpga Using Hands-On Projects, Nader Rafla, H. Shelton Jacinto, Luka Daoud

Electrical and Computer Engineering Faculty Publications and Presentations

Cybersecurity is an important concept in today’s age of information and is of major interest to keep information secure, helping to protect sensitive information in the presence of untrusted third-parties. This has presented the need for an implemented hardware variant of secure algorithms with small footprint to help add protection while reducing processing time/overhead on a standard processor.

In this work we present two hands-on projects that are designed specifically to teach these two concepts using project-based learning techniques in an innovative cooperative learning environment. The learning environment served to combine both student-peer learning and jigsaw strategies.

The technical contents …

Easing Students’ Transitions To University Via A Summer Bridge And Outdoor Experience Program, Noah Salzman, Ann Delaney, Catherine Rose Bates, Donna C. Llewellyn

Electrical and Computer Engineering Faculty Publications and Presentations

In this Complete Evidence-based Practice paper, we describe the development and evolution of a combined academic summer bridge program and outdoors experience program designed to support the academic success and development of incoming STEM majors at Boise State University. First-time, first-year students’ transitions to university can be challenging for a wide variety of reasons, including increased independence, leaving behind parents and friends while simultaneously struggling to form new peer groups, and adapting to more rigorous coursework with less externally imposed structure than prior learning experiences. These challenges, especially those related to students’ sense of belonging and connection to other students, …

Lessons Learned About Building An Assertive Community, Donna C. Llewellyn, William L. Hughes, Megan F. Gambs

Materials Science and Engineering Faculty Publications and Presentations

One of our observations in this lessons learned paper is that there is underwhelming faculty development related to scholarship other than on how to submit and sometimes how to write proposals. This de facto service model misses everything outside of the proposal-writing process; which is the least important, but is often the most celebrated, rewarded, and supported phase. Inspired by national Centers for Teaching & Learning, and modeled after the emerging Communities of Transformation literature, we are piloting a Center for Transformative Research at Boise State University. The vision of our Center is to build and sustain an ASSERTive community …

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 …

Using Reflection To Facilitate Writing Knowledge Transfer In Upper-Level Materials Science Courses, Jennifer C. Mallette, Harold Ackler

English Literature Faculty Publications and Presentations

When students enter upper-level engineering courses, they may bring with them unclear or inconsistent approaches to writing in engineering. Influenced by their past experiences with writing, students encountering engineering genres such as reports and proposals may struggle to write successfully. They may struggle in part because of the messiness inherent in writing knowledge transfer: a student who successfully completed freshman composition may still be unable to transfer skills, habits of mind, and approaches to writing from that setting to engineering because the rhetorical situations look drastically different. Yancey, Robertson, and Taczak define transfer as a “dynamic rather than a static …

Happy Hours Are A Godsend, Krishna Pakala, Diana Bairaktarova, Samantha Schauer

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Office hours that happen in a virtual environment are called virtual office hours. This type of student-faculty interaction can be easily hosted from a faculty computer/mobile device/tablet. With an invitation, students can login to the online session and join their instructor and peers in a virtual space. Using mobile technologies, students can join virtual office hours from a variety of locations including a library, outdoors, on a commute ride home, while caring for children, eating dinner, and even while grocery shopping. Virtual office hours allow for more flexibility of student-faculty interaction. They are an alternative to traditional office hours. This …

Work In Progress: First-Year Engineering College Students: Value Created From Participating In A Living/Learning Community, Krishna Pakala, Kim M.B. Tucker, Samantha Schauer

Mechanical and Biomedical Engineering Faculty Publications and Presentations

This Work in Progress paper examines how to capture the perceived value obtained from firstyear engineering college students (FYECS) from participating in the Engineering and Innovation Residential College (EIRC), a living learning community (LLC). People are social by nature and thrive through collaborating and living with others who share similar passions; however, oftentimes FYECS do not have a community of like-minded peers where support, innovation, discourse, and collaboration can take place. Adding to FYECS struggles is the fact that many do not have a mentor in their related field and are unable to start building their professional repertoire, network, technical …

Voices Of Our Students: Using Evidence-Based Methods To Inform A Multidisciplinary Engineering Program Design, Vicki Stieha, Noah Salzman, Amy J. Moll

Materials Science and Engineering Faculty Publications and Presentations

Listening carefully to our students and integrating the variables that matter to them is a step that we can take to increase the number of women and underrepresented minority graduates in engineering. This paper shares an evaluative case study as we report findings from data gathering tools guiding our continuous improvement process. The findings illuminate students’ perceptions of their engineering design course and curriculum. We conclude by discussing the pedagogical decisions the teaching team is making as a result of listening to our students’ voices.

High Speed Roll-To-Roll Printable Transistor Enabled By A Pulsed Light Curable Cnt Ink, Harish Subbaraman

Electrical and Computer Engineering Faculty Publications and Presentations

This paper reports the first high speed roll-to-roll printable transistor using a carbon nanotube (CNT) semiconducting layer. The transistor is made possible through the development of a pulsed light curable CNT ink compatible with typical drop on demand inkjet cartridges. This CNT ink uses a xylene based solvent with methanol, glycerin, and Triton X-100 modifiers to create an evaporable solution with appropriate absorption spectra for a mercury or xenon flash lamp with strong energy transmission in the UVB to mid visible light range, allowing the solution to absorb the energy from the flash lamp and evaporate. Transistor dimensions were defined …

Impact Of Beam Misalignment On Hybrid Beamforming Noma For Mmwave Communications, Mojtaba Ahmadi Almasi, Mojtaba Vaezi, Hani Mehrpouyan

Electrical and Computer Engineering Faculty Publications and Presentations

This paper analyzes the effect of beam misalignment on rate performance in downlink of hybrid beamforming-based non-orthogonal multiple access (HB-NOMA) systems. First an HB-NOMA framework is designed in multiuser millimeter wave (mmWave) communications. A sum-rate maximization problem is formulated for HB-NOMA, and an algorithm is introduced to design digital and analog precoders and efficient power allocation. Then, regarding perfectly aligned line-of-sight (LoS) channels, a lower bound for the achievable rate is derived. Next, when the users experience misaligned LoS or non-LoS (NLoS) channels, the impact of beam misalignment is evaluated. To this end, a misalignment factor is modeled and each …

Predicting Power-Transformer Bushings’ Seismic Vulnerability: Mounting Stiffness And Coupling, Jon Bender, Arvin Farid

Civil Engineering Faculty Publications and Presentations

Large power transformers are both expensive and vulnerable to seismic failure. Excessive amplification of earthquake loading to power transformer bushings beyond the bushings’ rated strength can occur if the system’s structural dynamics produce unpredictable and unfavorable resonance behavior. Determining the degree of vulnerability to large seismic amplifications is not straight-forward, and general design recommendations do not always resolve problems that can potentially arise. This paper considers a number of Case studies in an attempt to postulate a set of critical factors, which might facilitate better prediction of bushing amplification. Further, several additional Case studies are summarized in order to add …

Synergy And Timing: A Concurrent Mass Medical Campaign Predicted To Augment Indoor Residual Spraying For Malaria, Richard C. Elliott, David L. Smith, Dorothy C. Echodu

Materials Science and Engineering Faculty Publications and Presentations

Background: Control programmes for high burden countries are tasked with charting effective multi-year strategies for malaria control within significant resource constraints. Synergies between different control tools, in which more than additive benefit accrues from interventions used together, are of interest because they may be used to obtain savings or to maximize health impact per expenditure. One commonly used intervention in sub-Saharan Africa is indoor residual spraying (IRS), typically deployed through a mass campaign. While possible synergies between IRS and long-lasting insecticide-treated nets (LLINs) have been investigated in multiple transmission settings, coordinated synergy between IRS and other mass medical distribution campaigns …

A Robust Decision Support Leader-Follower Framework For Design Of Contamination Warning System In Water Distribution Network, Mohammad S. Khorshidi, Mohammad Reza Nikoo, Elham Ebrahimi, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

In recent years, several models have been proposed to inoculate Water Distribution Systems (WDS) against impacts of accidental and/or intentional compromised water quality through optimal deployment of online monitoring sensors in the network, which is referred to as Contamination Warning Systems (CWS). Translating such modeling efforts to real-world practice is, however, a challenge as different involved parties may pursue conflicting goals and modeling-based recommendations may not justify all stakeholders’ criteria. It is, hence, pivotal to develop conflict resolution methodologies to support engagement of different stakeholders in securing a safe water distribution. The decision making structure for CWS design is often …