Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Faculty Publications

Discipline
Institution
Keyword
Publication Year
File Type

Articles 1021 - 1050 of 3294

Full-Text Articles in Engineering

Comprehensive Second-Order Adjoint Sensitivity Analysis Methodology (2nd-Asam) Applied To A Subcritical Experimental Reactor Physics Benchmark: Iii. Effects Of Imprecisely Known Microscopic Fission Cross Sections And Average Number Of Neutrons Per Fission, Dan Gaberiel Cacuci, Ruixian Fang, J. A. Favorite, M. C. Badea, F. Di Rocco Oct 2019

Comprehensive Second-Order Adjoint Sensitivity Analysis Methodology (2nd-Asam) Applied To A Subcritical Experimental Reactor Physics Benchmark: Iii. Effects Of Imprecisely Known Microscopic Fission Cross Sections And Average Number Of Neutrons Per Fission, Dan Gaberiel Cacuci, Ruixian Fang, J. A. Favorite, M. C. Badea, F. Di Rocco

Faculty Publications

The Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) is applied to compute the first-order and second-order sensitivities of the leakage response of a polyethylene-reflected plutonium (PERP) experimental system with respect to the following nuclear data: Group-averaged isotopic microscopic fission cross sections, mixed fission/total, fission/scattering cross sections, average number of neutrons per fission (), mixed /total cross sections, /scattering cross sections, and /fission cross sections. The numerical results obtained indicate that the 1st-order relative sensitivities for these nuclear data are smaller than the 1st-order sensitivities of the PERP leakage response with respect to the total cross sections but are larger than those …

Go to article

First Principles Investigation Of Anomalous Pressure-Dependent Thermal Conductivity Of Chalcopyrites, Loay Flalfy, Denis Music, Ming Hu Oct 2019

First Principles Investigation Of Anomalous Pressure-Dependent Thermal Conductivity Of Chalcopyrites, Loay Flalfy, Denis Music, Ming Hu

Faculty Publications

The effect of compression on the thermal conductivity of CuGaS2, CuInS2, CuInTe2, and AgInTe2 chalcopyrites (space group I-42d) was studied at 300 K using phonon Boltzmann transport equation (BTE) calculations. The thermal conductivity was evaluated by solving the BTE with harmonic and third-order interatomic force constants. The thermal conductivity of CuGaS2 increases with pressure, which is a common behavior. Striking differences occur for the other three compounds. CuInTe2 and AgInTe2 exhibit a drop in the thermal conductivity upon increasing pressure, which is anomalous. AgInTe2 reaches a very low thermal conductivity of 0.2 W·m−1 ·K −1 at 2.6 GPa, being beneficial …

Go to article

Upcycling Single-Use Polyethylene Into High-Quality Liquid Products, Gokhan Celik, Robert M. Kennedy, Ryan A. Hackler, Magali Ferrandon, Akalanka Tennakoon, Smita Patnaik, Anne M. Lapointe, Salai Ammal, Andreas Heyden, Frédéric A. Perras, Marek Pruski, Susannah L. Scott, Kenneth R. Poeppelmeier, Aaron D. Sadow, Massimiliano Delferro Oct 2019

Upcycling Single-Use Polyethylene Into High-Quality Liquid Products, Gokhan Celik, Robert M. Kennedy, Ryan A. Hackler, Magali Ferrandon, Akalanka Tennakoon, Smita Patnaik, Anne M. Lapointe, Salai Ammal, Andreas Heyden, Frédéric A. Perras, Marek Pruski, Susannah L. Scott, Kenneth R. Poeppelmeier, Aaron D. Sadow, Massimiliano Delferro

Faculty Publications

Our civilization relies on synthetic polymers for all aspects of modern life; yet, inefficient recycling and extremely slow environmental degradation of plastics are causing increasing concern about their widespread use. After a single use, many of these materials are currently treated as waste, underutilizing their inherent chemical and energy value. In this study, energy-rich polyethylene (PE) macromolecules are catalytically transformed into value-added products by hydrogenolysis using well-dispersed Pt nanoparticles (NPs) supported on SrTiO3 perovskite nanocuboids by atomic layer deposition. Pt/SrTiO3 completely converts PE (Mn = 8000− 158,000 Da) or a single-use plastic bag (Mn = 31,000 Da) into high-quality liquid …

Go to article

Hydrologic Modeling As A Service (Hmaas): A New Approach To Address Hydroinformatic Challenges In Developing Countries, Michael A. Souffront Alcantara, E. James Nelson, Kiran Shakya, Christopher Edwards, Wade Roberts, Corey Krewson, Daniel P. Ames, Norman L. Jones, Angelica Gutierrez Oct 2019

Hydrologic Modeling As A Service (Hmaas): A New Approach To Address Hydroinformatic Challenges In Developing Countries, Michael A. Souffront Alcantara, E. James Nelson, Kiran Shakya, Christopher Edwards, Wade Roberts, Corey Krewson, Daniel P. Ames, Norman L. Jones, Angelica Gutierrez

Faculty Publications

Hydrologic modeling can be used to aid in decision-making at the local scale. Developed countries usually have their own hydrologic models; however, developing countries often have limited hydrologic modeling capabilities due to factors such as the maintenance, computational costs, and technical capacity needed to run models. A global streamflow prediction system (GSPS) would help decrease vulnerabilities in developing countries and fill gaps in areas where no local models exist by providing extensive results that can be filtered for specific locations. However, large-scale forecasting systems come with their own challenges. These New hydroinformatic challenges can prevent these models from reaching their …

Go to article

An Open-Source Tool To Facilitate The Processing Of Grace Observations And Gldas Outputs: An Evaluation In Bangladesh, Adam J. Purdy, Cédric H. David, Md. Safat Sikder, John T. Reager, Hrishikesh A. Chandanpukar, Norman L. Jones, Mir A. Matin Oct 2019

An Open-Source Tool To Facilitate The Processing Of Grace Observations And Gldas Outputs: An Evaluation In Bangladesh, Adam J. Purdy, Cédric H. David, Md. Safat Sikder, John T. Reager, Hrishikesh A. Chandanpukar, Norman L. Jones, Mir A. Matin

Faculty Publications

Bangladesh lies at the intersection of the Ganges, Brahmaputra, and Meghna rivers with a combined average discharge of 38,000 m3s−1 ranking fourth globally. Despite the volume of water flowing through and seasonally inundating parts of the landscape, groundwater reliance is necessary to support an intensive agricultural industry. Here we use newly-developed open-source software to combine observations from the Gravity Recovery and Climate Experiment (GRACE) satellites with hydrologic estimates of land water storage from the Global Land Assimilation Data System (GLDAS) to isolate basin-scale groundwater anomalies in Northwest Bangladesh from 2002 to 2016. We place our estimates in the context of …

Go to article

Enabling Stakeholder Decision-Making With Earth Observation And Modeling Data Using Tethys Platform, E. James Nelson, Sarva T. Pulla, Mir A. Matin, Kiran Shakya, Norm Jones, Daniel P. Ames, W. Lee Ellenburg, Kel N. Markert, Cédric H. David, Benjamin F. Zaitchik, Patrick Gatlin, Riley Hales Oct 2019

Enabling Stakeholder Decision-Making With Earth Observation And Modeling Data Using Tethys Platform, E. James Nelson, Sarva T. Pulla, Mir A. Matin, Kiran Shakya, Norm Jones, Daniel P. Ames, W. Lee Ellenburg, Kel N. Markert, Cédric H. David, Benjamin F. Zaitchik, Patrick Gatlin, Riley Hales

Faculty Publications

Tethys Platform is an open source framework for developing web-based applications for Earth Observation data. Our experience shows that Tethys significantly lowers the barrier for cloud-based app development, simplifies the process of accessing scalable distributed cloud computing resources and leverages additional software for data and computationally intensive modeling. The Tethys software development kit allows users to create web apps for visualizing, analyzing, and modeling Earth Observation data. Tethys platform provides a collaborative environment for scientists to develop and deploy several Earth Observation web applications across multiple Tethys portals. We work in partnership with leading regional organizations world-wide to help developing …

Go to article

Ligaos Is A Fast Li-Ion Conductor: A First-Principles Prediction, Xueling Lei, Wenjun Wu, Bo Xu, Chuying Ouyang, Kevin Huang Oct 2019

Ligaos Is A Fast Li-Ion Conductor: A First-Principles Prediction, Xueling Lei, Wenjun Wu, Bo Xu, Chuying Ouyang, Kevin Huang

Faculty Publications

Solid Li-ion conducting electrolytes are highly sought for all solid-state Li-batteries, which are considered the next-generation safe batteries. Here a systematic computational study on the intrinsic transport properties of lithium gallium oxysulfide, LiGaOS (S. G. Pmc21), as a potential solid-state Li-ion electrolyte have been reported. The phonon dispersion spectrum analysis indicates that LiGaOS crystal structure is dynamically stable. The energy band structure and density of states calculations suggest that LiGaOS is an insulator with a wide indirect band gap of ∼5.44 eV. The CI-NEB calculations reveal that the “kick-off” collective migration via Li-interstitials is the dominant conduction mechanism …

Go to article

A Hybrid Kinematic-Acoustic System For Automated Activity Detection Of Construction Equipment, Yong-Cheol Lee Oct 2019

A Hybrid Kinematic-Acoustic System For Automated Activity Detection Of Construction Equipment, Yong-Cheol Lee

Faculty Publications

Automatically recognizing and tracking construction equipment activities is the first step towards performance monitoring of a job site. Recognizing equipment activities helps construction managers to detect the equipment downtime/idle time in a real-time framework, estimate the productivity rate of each equipment based on its progress, and efficiently evaluate the cycle time of each activity. Thus, it leads to project cost reduction and time schedule improvement. Previous studies on this topic have been based on single sources of data (e.g., kinematic, audio, video signals) for automated activity-detection purposes. However, relying on only one source of data is not appropriate, as the …

Go to article

Synthesis Of Samarium-Based Metal Organic Compound Nanoparticles With Polychromatic-Photoluminescence For Bio-Tissue Fluorescence Imaging, Jian Xu Oct 2019

Synthesis Of Samarium-Based Metal Organic Compound Nanoparticles With Polychromatic-Photoluminescence For Bio-Tissue Fluorescence Imaging, Jian Xu

Faculty Publications

The development of nanomaterials with special optical window is critical for clinical applications and the optoelectronic industry. In this work, eight kinds of samarium-based metal organic compound nanoparticles (Sm-Fe, Sm-Ga, Sm-Mn, Sm-Na, Sm-Nb, Sm-W, Sm-Cu, and Sm-Al) were synthesized through a solution method. They show polychromatic-photoluminescence spectra extended from the UV to near-infrared (NIR) region when excited by 280 nm, 380 nm, 480 nm, 580 nm, and 785 nm light. They emit direct white light with respect to UV excitation. Tunable white-to-green fluorescence can be achieved by variation of excitation light around 300-400 nm. When they are excited by a …

Go to article

Nonlinearities And Carrier Dynamics In Refractory Plasmonic Tin Thin Films, Heather George, Jennifer Reed, Manuel R. Ferdinandus, Clayton Devault, Alexei Lagutchev, Augustine Urbas, Theodore B. Norris, Vladimir M. Shalaev, Alexandra Boltasseva, Nathaniel Kinsey Oct 2019

Nonlinearities And Carrier Dynamics In Refractory Plasmonic Tin Thin Films, Heather George, Jennifer Reed, Manuel R. Ferdinandus, Clayton Devault, Alexei Lagutchev, Augustine Urbas, Theodore B. Norris, Vladimir M. Shalaev, Alexandra Boltasseva, Nathaniel Kinsey

Faculty Publications

Titanium nitride is widely used in plasmonic applications, due to its robustness and optical properties which resemble those of gold. Despite this interest, the nonlinear properties have only recently begun to be investigated. In this work, beam deflection and non-degenerate femtosecond pump-probe spectroscopy (800 nm pump and 650 nm probe) were used to measure the real and imaginary transient nonlinear response of 30-nm-thick TiN films on sapphire and fused silica in the metallic region governed by Fermi-smearing nonlinearities. In contrast to other metals, it is found that TiN exhibits non-instantaneous positive refraction and reverse saturable absorption whose relaxation is dominated …

Go to article

Insulation Sensitivity Analysis For An Optimized Fabric Shelter Off-Grid Hybrid Energy System, Jay F. Pearson, Torrey J. Wagner, Steven Schuldt Oct 2019

Insulation Sensitivity Analysis For An Optimized Fabric Shelter Off-Grid Hybrid Energy System, Jay F. Pearson, Torrey J. Wagner, Steven Schuldt

Faculty Publications

During military and disaster relief operations, connecting to an established electrical grid is rarely an option. In these situations, camps consisting of poorly insulated fabric shelters are predominantly powered by inefficient diesel generators that require frequent fuel resupply. In order to reduce the fuel demand of these generators, camps may utilize photovoltaic-battery systems. This paper presents an innovative cost-performance model capable of optimizing solar array size, battery backup system, and shelter insulation type to minimize the operating cost of powering a single fabric shelter. Model performance was evaluated using one year of insolation, weather and energy requirement data from a …

Go to article

Wind Farm Layout Optimization With Loads Considerations, Andrew P. J. Stanley, Jennifer King, Andrew Ning Oct 2019

Wind Farm Layout Optimization With Loads Considerations, Andrew P. J. Stanley, Jennifer King, Andrew Ning

Faculty Publications

The objective of this paper is to improve the annual energy production of a wind farm by optimizing the layout of a wind farm, while considering fatigue loads on turbines. In this paper, the loads are estimated using the edgewise bending moment computed using CCBlade, a steady-state blade element momentum code. The edgewise bending moment is then used to calculate fatigue damage using Miner’s rule. The fatigue damage is used to constrain the layout optimization problem. We show that our method can predict blade root damage with similar trends to damage calculated with other methods, such as a complex, computationally …

Go to article

Air Force Space Programs: Comparing Estimates To Final Development Budgets, Christopher Elworth, Edward D. White, Jonathan D. Ritschel, Gregory E. Brown Oct 2019

Air Force Space Programs: Comparing Estimates To Final Development Budgets, Christopher Elworth, Edward D. White, Jonathan D. Ritschel, Gregory E. Brown

Faculty Publications

This article analyzes how development budget estimates, as reported in the Selected Acquisition Reports, change over time for primarily Air Force space programs. Government acquisition policy emphasizes the importance of developing an accurate point estimate for programs to ensure program budget efficiency; however, statistics imply space programs tend to underspend at the beginning of the program and to overspend at the end of Initial Operational Capability. This suggests new phasing methods that reflect the unique needs of space and perhaps other developmental-type programs by allocating more of the budget in later years rather than at the beginning of the program, …

Go to article

Possible Detection Of Low Energy Solar Neutrons Using Boron Based Materials, Nicole Benker, Elena Echeverria, Robert Olesen, Brant E. Kananen, John W. Mcclory, Yaroslav V. Burak, Volodymyr T. Adamiv, Ihor M. Teslyuk, George Glenn Peterson, Ben Bradley, Ethiyal R. Wilson, James C. Petrosky, Bin Dong, Jeffry Kelber, Jennifer Hamblin, Jaques Doumani, Peter A. Dowben, Alex Enders Oct 2019

Possible Detection Of Low Energy Solar Neutrons Using Boron Based Materials, Nicole Benker, Elena Echeverria, Robert Olesen, Brant E. Kananen, John W. Mcclory, Yaroslav V. Burak, Volodymyr T. Adamiv, Ihor M. Teslyuk, George Glenn Peterson, Ben Bradley, Ethiyal R. Wilson, James C. Petrosky, Bin Dong, Jeffry Kelber, Jennifer Hamblin, Jaques Doumani, Peter A. Dowben, Alex Enders

Faculty Publications

Solar neutrons have been detected aboard the International Space Station (ISS), using lithium tetraborate and boron carbide detector elements. We find that evidence of a solar neutron flux, as detected in a neutron calorimeter following subtraction of the proton background, with an energy of about 2 to 4 MeV. This solar neutron flux is likely no more than 250 to 375 neutrons cm−2sec−1, with a lower bound of 50–75 neutrons cm−2sec−1 at one au.

Go to article

Optical Response Of Bifeo3 Films Subjected To Uniaxial Strain, Andrew Herklotz, Stefania Rus, Changhee Sohn, Santosh Kc, Valentino Cooper, Er-Jia Guo, Thomas Ward Sep 2019

Optical Response Of Bifeo3 Films Subjected To Uniaxial Strain, Andrew Herklotz, Stefania Rus, Changhee Sohn, Santosh Kc, Valentino Cooper, Er-Jia Guo, Thomas Ward

Faculty Publications

The impact of single-axis lattice expansion on the optical response of BiFeO3 films is examined. Low-energy He implantation is used to tailor morphotropic phases of BiFeO3 films and study changes in their optical spectra with continuously increasing lattice expansion. He ion implantation of epitaxial rhombohedral (R)- and tetragonal (T)-like BiFeO3 films induces uniaxial out-of-plane strain that, on R-like films, eventually leads to a complete R-T phase transition. This approach allows us to provide insights into the optical response of BiFeO3 films. Strain doping of T-like films leads to a significant redshift of the optical absorption spectra that is theoretically explained …

Go to article

Adhesion Testing Of Printed Inks While Varying The Surface Treatment Of Polymer Substrates, Clayton Neff, Edwin Elston, Amanda Schrand, Nathan B. Crane Sep 2019

Adhesion Testing Of Printed Inks While Varying The Surface Treatment Of Polymer Substrates, Clayton Neff, Edwin Elston, Amanda Schrand, Nathan B. Crane

Faculty Publications

Additive manufacturing with conductive materials enables new approaches to printed electronics that are unachievable by standard electronics manufacturing processes. In particular, electronics can be embedded directly into structural components in nearly arbitrary 3D space. While these methods incorporate many of the same materials, the new processing methods require standard test methods to compare materials, processing conditions, and determine design limits. This work demonstrates a test method to quantitatively measure the adhesion failure of printed inks deposited on a substrate without changing the ink printing conditions. The proposed method is an adaption of single lap shear testing in which the lap …

Go to article

Evaluation And Demonstration Of Take Home Laboratory Kit, J. A. Rossiter, S. A. Pope, B. Ll. Jones, John Hedengren Sep 2019

Evaluation And Demonstration Of Take Home Laboratory Kit, J. A. Rossiter, S. A. Pope, B. Ll. Jones, John Hedengren

Faculty Publications

This paper discusses some of the reasons for producing take home laboratory kits. This is then supplemented by detailed presentation of three different types of take home kit, alongside the motivations for their design and an evaluation of their efficacy with students.

Go to article

Preparation Of Activated Biochar-Supported Magnetite Composite For Adsorption Of Polychlorinated Phenols From Aqueous Solutions, Byung-Moon Jun, Yejin Kim, Jonghun Han, Yeomin Yoon, Chang Min Park Sep 2019

Preparation Of Activated Biochar-Supported Magnetite Composite For Adsorption Of Polychlorinated Phenols From Aqueous Solutions, Byung-Moon Jun, Yejin Kim, Jonghun Han, Yeomin Yoon, Chang Min Park

Faculty Publications

For this study, we applied activated biochar (AB) and its composition with magnetite (AB-Fe3O4) as adsorbents for the removal of polychlorophenols in model wastewater. We comprehensively characterized these adsorbents and performed adsorption tests under several experimental parameters. Using FTIR, we confirmed successful synthesis of AB-Fe3O4 composite through cetrimonium bromide surfactant. We conducted adsorption tests using AB and AB-Fe3O4 to treat model wastewater containing polychlorophenols, such as 2,3,4,6-Tetrachlorophenol (TeCP), 2,4,6-Trichlorophenol (TCP), and 2,4-Dichlorophenol (DCP). Results of the isotherm and the kinetic experiments were well adapted to Freundlich’s isotherm model and the …

Go to article

Peptide Nanotube Encapsulated Enzyme Biosensor For Vapor Phase Detection Of Malathion, An Organophosphorus Compound, Christopher W. Edwards, Surachet Duanghathaipornsuk, Mark N. Goltz, Sushil Kanel, Dong-Shik Kim Sep 2019

Peptide Nanotube Encapsulated Enzyme Biosensor For Vapor Phase Detection Of Malathion, An Organophosphorus Compound, Christopher W. Edwards, Surachet Duanghathaipornsuk, Mark N. Goltz, Sushil Kanel, Dong-Shik Kim

Faculty Publications

This study explores the use of a butyrylcholinesterase (BChE)-based, reversible reaction biosensor using screen-printed electrodes (SPEs) having a smaller working surface area than the single-use electrodes previously studied. Previous research demonstrated the prospective application of a single-use biosensor fabricated with an acetylcholinesterase (AChE) enzyme encapsulated in peptide nanotubes (PNTs) and enhanced with horseradish peroxidase (HRP) to detect organophosphorus compounds (OPCs) in aqueous and gas phases. In the current study, potential improvements to the biosensor are investigated. BChE-based biosensors were fabricated using PNTs, HRP, and Nafion in combination to increase the reactive surface area, enhance sensitivity, and maintain enzyme stability. Cyclic …

Go to article

Segmentation Of Severe Occupational Incidents In Agribusiness Industries Using Latent Class Clustering, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher Sep 2019

Segmentation Of Severe Occupational Incidents In Agribusiness Industries Using Latent Class Clustering, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher

Faculty Publications

One of the principle objectives in occupational safety analysis is to identify the key factors that affect the severity of an incident. To identify risk groups of occupational incidents and the factors associated with them, statistical analysis of workers’ compensation claims data is performed using latent class clustering, for the segmentation of 1031 severe occupational incidents in agribusiness industries in the Midwest region of the United States between 2008–2016. In this study, severe incidents are those with workers’ compensation costs equal to or greater than $100,000 (USD). Based on the latent class clustering results, three risk groups are identified with …

Go to article

Fkrr-Mvsf: A Fuzzy Kernel Ridge Regression Model For Identifying Dna-Binding Proteins By Multi-View Sequence Features Via Chou's Five-Step Rule, Yi Zou, Yije Ding, Jijun Tang, Fei Guo, Li Peng Sep 2019

Fkrr-Mvsf: A Fuzzy Kernel Ridge Regression Model For Identifying Dna-Binding Proteins By Multi-View Sequence Features Via Chou's Five-Step Rule, Yi Zou, Yije Ding, Jijun Tang, Fei Guo, Li Peng

Faculty Publications

DNA-binding proteins play an important role in cell metabolism. In biological laboratories, the detection methods of DNA-binding proteins includes yeast one-hybrid methods, bacterial singles and X-ray crystallography methods and others, but these methods involve a lot of labor, material and time. In recent years, many computation-based approachs have been proposed to detect DNA-binding proteins. In this paper, a machine learning-based method, which is called the Fuzzy Kernel Ridge Regression model based on Multi-View Sequence Features (FKRR-MVSF), is proposed to identifying DNA-binding proteins. First of all, multi-view sequence features are extracted from protein sequences. Next, a Multiple Kernel Learning (MKL) algorithm …

Go to article

Quantitative Analysis Of Cerium-Gallium Alloys Using A Hand-Held Laser Induced Breakdown Spectroscopy Device, Ashwin P. Rao, Matthew Cook, Howard L. Hall, Michael B. Shattan Sep 2019

Quantitative Analysis Of Cerium-Gallium Alloys Using A Hand-Held Laser Induced Breakdown Spectroscopy Device, Ashwin P. Rao, Matthew Cook, Howard L. Hall, Michael B. Shattan

Faculty Publications

A hand-held laser-induced breakdown spectroscopy device was used to acquire spectral emission data from laser-induced plasmas created on the surface of cerium-gallium alloy samples with Ga concentrations ranging from 0–3 weight percent. Ionic and neutral emission lines of the two constituent elements were then extracted and used to generate calibration curves relating the emission line intensity ratios to the gallium concentration of the alloy. The Ga I 287.4-nm emission line was determined to be superior for the purposes of Ga detection and concentration determination. A limit of detection below 0.25%was achieved using a multivariate regression model of the Ga I …

Go to article

Ion Software-Defined Radio Metadata Standard Final Report, Sanjeev Gunawardena, Alexander Rugamer, Muhammad Subhan Hameed, Markel Arizabaleta, Thomas Pany, Javier Arribas Sep 2019

Ion Software-Defined Radio Metadata Standard Final Report, Sanjeev Gunawardena, Alexander Rugamer, Muhammad Subhan Hameed, Markel Arizabaleta, Thomas Pany, Javier Arribas

Faculty Publications

The ION GNSS SDR Metadata Standard describes the formatting and other essential PNT-related parameters of sampled data streams and files. This allows processors to seamlessly consume such data without the need to input these parameters manually. The technical development phase of the initial version of the standard has now been deemed complete and is currently undergoing the last remaining procedural steps towards adoption as a formal standard by the Institute of Navigation. This paper reports on the activities of the working group since September 2018 and summarizes the final products of the standard. It also reports on examples of early …

Go to article

Mechanical And Temperature Resilience Of Multi-Material Systems For Printed Electronics Packaging, Clayton Neff, Justin Nussbaum, Chris Gardiner, Nathan B. Crane, James L. Zunino, Mike Newton Sep 2019

Mechanical And Temperature Resilience Of Multi-Material Systems For Printed Electronics Packaging, Clayton Neff, Justin Nussbaum, Chris Gardiner, Nathan B. Crane, James L. Zunino, Mike Newton

Faculty Publications

In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of ‘printed packaging’ that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology—coined large area projection sintering (LAPS)—manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate …

Go to article

Reduction Of A Detailed Soot Model For Simulations Of Pyrolysing Solid Fuels, Alexander J. Josephson, Emily M. Hopkins, David O. Lignell, Rod R. Linn Aug 2019

Reduction Of A Detailed Soot Model For Simulations Of Pyrolysing Solid Fuels, Alexander J. Josephson, Emily M. Hopkins, David O. Lignell, Rod R. Linn

Faculty Publications

This work presents a computationally inexpensive soot formation model for use in simulating large solid-complex fuel systems. The proposed model evaluates three variables: number density of tars, bulk mass density of soot particles, and particle number density. Each of these variables are influenced by soot formation phenomena, and this model evaluates the most common of these phenomena: soot nucleation, surface reactions, and coagulation. Two separate simulations were carried out using this model and results were compared against simulations using a more detailed and computationally expensive model. Results are promising and show a meaningful reduction in model complexity and computational cost …

Go to article

Near-Field Effects On Partially Coherent Light Scattered By An Aperture, Milo W. Hyde Iv, Michael J. Havrilla Aug 2019

Near-Field Effects On Partially Coherent Light Scattered By An Aperture, Milo W. Hyde Iv, Michael J. Havrilla

Faculty Publications

We investigate how the near field affects partially coherent light scattered from an aperture in an opaque screen. Prior work on this subject has focused on the role of surface plasmons, and how they affect spatial coherence is well documented. Here, we consider other near-field effects that might impact spatial coherence. We do this by examining the statistics of the near-zone field scattered from an aperture in a perfect electric conductor plane—a structure that does not support surface plasmons. We derive the near-field statistics (in particular, cross-spectral density functions) by applying electromagnetic equivalence theorems and the Method of Moments. We …

Go to article

Characterization Of Mechanical Properties Of Thin-Film Li-Ion Battery Electrodes From Laser Excitation And Measurements Of Zero Group Velocity Resonances, Jing Yao, Joseph Cassler, Dean R. Wheeler, Brian A. Mazzeo Aug 2019

Characterization Of Mechanical Properties Of Thin-Film Li-Ion Battery Electrodes From Laser Excitation And Measurements Of Zero Group Velocity Resonances, Jing Yao, Joseph Cassler, Dean R. Wheeler, Brian A. Mazzeo

Faculty Publications

The mechanical properties of thin-film Li-ion battery electrodes are controlled by the microstructure of the constituent materials. In this work, a noncontact and nondestructive measurement of the mechanical properties of electrode films is performed by measurement of zero-group velocity (ZGV) resonances. Theoretical models are used to quantify the sensitivity of the ZGV resonances to changes in mechanical properties. The ZGV Lamb modes of a solid bilayer consisting of a thin metallic layer and a thin compliant coating layer are shown to be dependent on Young’s moduli, thicknesses, densities, and Poisson’s ratios of the layers. Experimental ZGV resonances are excited using …

Go to article

Limited Data Rolling Bearing Fault Diagnosis With Few-Shot Learning, Ansi Zhang, Shaobo Li, Yuxin Cui, Wanli Yang, Rongzhi Dong, Jianjun Hu Aug 2019

Limited Data Rolling Bearing Fault Diagnosis With Few-Shot Learning, Ansi Zhang, Shaobo Li, Yuxin Cui, Wanli Yang, Rongzhi Dong, Jianjun Hu

Faculty Publications

This paper focuses on bearing fault diagnosis with limited training data. A major challenge in fault diagnosis is the infeasibility of obtaining sufficient training samples for every fault type under all working conditions. Recently deep learning based fault diagnosis methods have achieved promising results. However, most of these methods require large amount of training data. In this study, we propose a deep neural network based few-shot learning approach for rolling bearing fault diagnosis with limited data. Our model is based on the siamese neural network, which learns by exploiting sample pairs of the same or different categories. Experimental results over …

Go to article

Use Of Logistic Regression To Identify Factors Influencing The Post-Incident State Of Occupational Injuries In Agribusiness Operations, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher Aug 2019

Use Of Logistic Regression To Identify Factors Influencing The Post-Incident State Of Occupational Injuries In Agribusiness Operations, Fatemeh Davoudi Kakhki, Steven Freeman, Gretchen Mosher

Faculty Publications

Agribusiness industries are among the most hazardous workplaces for non-fatal occupational injuries. The term “post-incident state” is used to describe the health status of an injured person when a non-fatal occupational injury has occurred, in the post-incident period when the worker returns to work, either immediately with zero days away from work (medical state) or after a disability period (disability state). An analysis of nearly 14,000 occupational incidents in agribusiness operations allowed for the classification of the post-incident state as medical or disability (77% and 23% of the cases, respectively). Due to substantial impacts of occupational incidents on labor-market outcomes, …

Go to article

Generalized Beam–Spring Model For Predicting Elastic Behavior Of Partially Composite Concrete Sandwich Wall Panels, Salam Al-Rubaye, Taylor Sorensen, Robert J. Thomas, Marc Maguire Aug 2019

Generalized Beam–Spring Model For Predicting Elastic Behavior Of Partially Composite Concrete Sandwich Wall Panels, Salam Al-Rubaye, Taylor Sorensen, Robert J. Thomas, Marc Maguire

Faculty Publications

Partially composite sandwich wall panels (SWP) have been used in the construction industry for at least twenty years. Currently there is limited codified guidance for designers of partially composite concrete SWP, but they are being designed safely and routinely. Design is often guided by the composite connector manufacturers who sell proprietary composite connectors often using a variation of truss-type matrix methods for prediction of elastic behavior of SWPs. The purpose of this paper is to quantify the accuracy of such a model in a uniform manner by developing a generalized version of these matrix models called the beam-spring model (BSM). …

Go to article

First Prev Next Last