Engineering Commons^™

Stainless-Steel Column For Robust High Temperature Microchip Gas Chromatography, Abhijit Ghosh, Austin R. Foster, Jacob C. Johnson, Carlos R. Vilorio, Luke T. Tolley, Brian D. Iverson, Aaron R. Hawkins, H. Dennis Tolley, Milton L. Lee

Faculty Publications

This paper reports the first results of a robust, high performance, stainless-steel microchip gas chromatography (GC) column that is capable of analyzing complex real world mixtures as well as operating at very high temperatures. Using a serpentine design, a 10 m column with an approximately semicircular cross section with a 52 µm hydraulic diameter (D_h) was produced in a 17 cm x 6.3 cm x 0.1 cm rectangular steel chip. The channels were produced using a multilayer chemical etch and diffusion bonding process, and metal nuts were brazed onto the inlet and outlet ports allowing for column interfacing …

Towards Overcoming The Curse Of Dimensionality: The Third-Order Adjoint Method For Sensitivity Analysis Of Response-Coupled Linear Forward/Adjoint Systems, Uncertainty Quantification And Predictive Modeling With Applications To Nuclear Energy Systems, Dan Gabriel Cacuci

Faculty Publications

This work presents the Third-Order Adjoint Sensitivity Analysis Methodology (3rd-ASAM) for response-coupled forward and adjoint linear systems. The 3rd-ASAM enables the efficient computation of the exact expressions of the 3rd-order functional derivatives (“sensitivities”) of a general system response, which depends on both the forward and adjoint state functions, with respect to all of the parameters underlying the respective forward and adjoint systems. Such responses are often encountered when representing mathematically detector responses and reaction rates in reactor physics problems. The 3rd-ASAM extends the 2nd-ASAM in the quest to overcome the “curse of dimensionality” in sensitivity analysis, uncertainty quantification and predictive …

Towards Overcoming The Curse Of Dimensionality: The Third-Order Adjoint Method For Sensitivity Analysis Of Response-Coupled Linear Forward/Adjoint Systems, With Applications To Uncertainty Quantification And Predictive Modeling, Dan Gabriel Cacuci

Faculty Publications

This work presents the Third-Order Adjoint Sensitivity Analysis Methodology (3rd-ASAM) for response-coupled forward and adjoint linear systems. The 3rd-ASAM enables the efficient computation of the exact expressions of the 3rd-order functional derivatives ("sensitivities") of a general system response, which depends on both the forward and adjoint state functions, with respect to all of the parameters underlying the respective forward and adjoint systems. Such responses are often encountered when representing mathematically detector responses and reaction rates in reactor physics problems. The 3rd-ASAM extends the 2nd-ASAM in the quest to overcome the "curse of dimensionality" in sensitivity analysis, uncertainty quantification and predictive …

Comprehensive Second-Order Adjoint Sensitivity Analysis Methodology (2nd-Asam) Applied To A Subcritical Experimental Reactor Physics Benchmark: I. Effects Of Imprecisely Known Microscopic Total And Capture Cross Sections, Daniel Gabriel Cacuci, Ruixian Fang, Jeffrey A. Favorite

Faculty Publications

The subcritical polyethylene-reflected plutonium (PERP) metal fundamental physics benchmark, which is included in the Nuclear Energy Agency (NEA) International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook, has been selected to serve as a paradigm illustrative reactor physics system for the application of the Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) that was developed by Cacuci. The 2nd-ASAM enables the exhaustive deterministic computation of the exact values of the 1st-order and 2nd-order sensitivities of a system response to the parameters underlying the respective system. The PERP benchmark is numerically modeled in this work by using the deterministic multigroup neutron transport equation discretized …

Comprehensive Second-Order Adjoint Sensitivity Analysis Methodology (2nd-Asam) Applied To A Subcritical Experimental Reactor Physics Benchmark: Ii. Effects Of Imprecisely Known Microscopic Scattering Cross Sections, Daniel Gabriel Cacuci, Ruixian Fang

Faculty Publications

This work continues the presentation commenced in Part I of the second-order sensitivity analysis of nuclear data of a polyethylene-reflected plutonium (PERP) benchmark using the Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM). This work reports the results of the computations of the first- and second-order sensitivities of this benchmark's computed leakage response with respect to the benchmark's 21,600 parameters underlying the computed group-averaged isotopic scattering cross sections. The numerical results obtained for the 21,600 first-order relative sensitivities indicate that the majority of these were small, the largest having relative values of O (10(-2)). Furthermore, the vast majority of the (21600)(2) second-order …

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 …

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 …

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 …

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 …

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 …

Communication: First-Principles Evaluation Of Alkali Ion Adsorption And Ion Exchange In Pure Silica Lta Zeolite (Vol 149, 131102, 2018), Vancho Kocevski, Benjamin D. Zeidman, Charles H. Henager Jr., Theodore M. Besmann

Faculty Publications

Using first-principles calculations, we studied the adsorption of alkali ions in pure silica Linde Type A (LTA) zeolite. The probability of adsorbing alkali ions from solution and the driving force for ion exchange between Na+ and other alkali ions at the different adsorption sites were analyzed. From the calculated ion exchange isotherms, we show that it is possible to exchange Na+ with K+ and Rb+ in water, but that is not the case for systems in a vacuum. We also demonstrate that a solvation model should be used for the accurate representation of ion exchange in an LTA and that …

Relative Navigation Of Fixed-Wing Aircraft In Gps-Denied Environments, Gary J. Ellingson, Kevin M. Brink, Timothy Mclain

Faculty Publications

The future impact of small unmanned aircraft will depend in part on how well they can navigate in GPS-denied and GPS-degraded environments. While several GPS-denied navigation methods have been introduced, small fixed-wing aircraft have, for the most part, been neglected. This paper introduces a method to enable GPS-denied fixed-wing flight while accounting for fixed-wing-specific sensing requirements. This work uses a methodology called relative navigation as an overarching framework. The development of an odometry-like, front-end, EKF-based estimator that utilizes only a monocular camera and an inertial measurement unit is presented. The filter uses the measurement model of the multi-state-constraint Kalman filter. …

Wetting Metamorphosis Of Hydrophobic Fluoropolymer Coatings Submerged In Water And Ultrasonically Vibrated, Matthew Trapuzzano, Nathan B. Crane, Rasim Guldiken, Andrés Tejada-Martínez

Faculty Publications

Many important processes, from manufacture of integrated circuit boards, to an insect’s ability to walk on water, depend on the wetting of liquids on surfaces. Wetting is commonly controlled through material selection, coatings, and/or surface texture. However, wetting is sensitive to environmental conditions. In particular, some hydrophobic fluoropolymer coatings are sensitive to extended water exposure as evidenced by a declining contact angle and increasing contact angle hysteresis. Understanding “degradation” of these coatings is critical to applications that employ them. The durability of a series of fluoropolymer coatings were tested by measuring the contact angle before, during, and after extended submersion …

Takeoff And Performance Tradeoffs Of Retrofit Distributed Electric Propulsion For Urban Transport, Kevin Moore, Andrew Ning

Faculty Publications

While vertical takeoff and landing aircraft have shown promise for urban air transport, distributed electric propulsion on existing aircraft may offer immediately implementable alternatives. Distributed electric propulsion could potentially decrease takeoff distances enough to enable thousands of potential inter-city runways. This conceptual study explores the effects of a retrofit of open-bladed electric propulsion units. To model and explore the design space we use blade element momentum method, vortex lattice method, linear-beam finite element analysis, classical laminate theory, composite failure, empirically-based blade noise modeling, motor and motor-controller mass models, and gradient-based optimization. With liftoff time of seconds and the safe total …

Binder Jetting: A Review Of Process, Materials, And Methods, Mohsen Ziaee, Nathan B. Crane

Faculty Publications

Binder Jet printing is an additive manufacturing technique that dispenses liquid binding agent on powder. Layers are formed repeatedly to build up a physical article. Binder jetting (BJ) can be adapted to almost any powder with high production rates. The BJ process utilizes a broad range of technologies including printing methods, powder deposition, dynamic binder/powder interaction, and post-processing methods. A wide variety of materials have been demonstrated including polymers, metals, and ceramics, but a common challenge is developing printing and post-processing methods that maximize part performance. This article presents a broad review of technologies and approaches that have been applied …

Simulated Tremor Propagation In The Upper Limb: From Muscle Activity To Joint Displacement, Thomas Corie, Steven Knight Charles

Faculty Publications

Although tremor is the most common movement disorder, there are few non-invasive treatment options. Creating effective tremor suppression devices requires a knowledge of where tremor originates mechanically (which muscles) and how it propagates through the limb (to which degrees of freedom, DOF).

To simulate tremor propagation, we created a simple model of the upper limb, with tremorogenic activity in the 15 major superficial muscles as inputs and tremulous joint displacement in the 7 major DOF as outputs. The model approximated the muscle excitation-contraction dynamics, musculoskeletal geometry, and mechanical impedance of the limb.

From our simulations, we determined fundamental principles for …

Transverse Vibration Of Clamped-Pinned-Free Beam With Mass At Free End, Jonathan Hong, Jacob Dodson, Simon Laflamme, Austin Downey

Faculty Publications

Engineering systems undergoing extreme and harsh environments can often times experience rapid damaging effects. In order to minimize loss of economic investment and human lives, structural health monitoring (SHM) of these high-rate systems is being researched. An experimental testbed has been developed to validate SHM methods in a controllable and repeatable laboratory environment. This study applies the Euler-Bernoulli beam theory to this testbed to develop analytical solutions of the system. The transverse vibration of a clamped-pinned-free beam with a point mass at the free end is discussed in detail. Results are derived for varying pin locations and mass values. Eigenvalue …

Intrinsic Coating Morphology Modulates Acute Drug Transfer In Drug-Coated Balloon Therapy, Gary H. Chang, Dara A. Azar, Chimera Lyle, Vipul C. Chitalia, Tarek Shazly, Vijaya B. Kolachalama

Faculty Publications

The hallmark of drug-coated balloon (DCB) therapy for the treatment of peripheral vascular disease is that it allows for reopening of the narrowed lumen and local drug delivery without the need for a permanent indwelling metal implant such as a stent. Current DCB designs rely on transferring drugs such as paclitaxel to the arterial vessel using a variety of biocompatible excipients coated on the balloons. Inherent procedural challenges, along with limited understanding of the interactions between the coating and the artery, interactions between the coating and the balloon as well as site-specific differences, have led to DCB designs with poor …

Concrete Crack Detection And Monitoring Using A Capacitive Dense Sensor Array, Jin Yan, Austin Downey, Alessandro Cancelli, Simon Laflamme, An Chen, Jian Li, Filippo Ubertini

Faculty Publications

Cracks in concrete structures can be indicators of important damage and may significantly affect durability. Their timely identification can be used to ensure structural safety and guide on-time maintenance operations. Structural health monitoring solutions, such as strain gauges and fiber optics systems, have been proposed for the automatic monitoring of such cracks. However, these solutions become economically difficult to deploy when the surface under investigation is very large. This paper proposes to leverage a novel sensing skin for monitoring cracks in concrete structures. This sensing skin is constituted of a flexible electronic termed soft elastomeric capacitor, which detects a change …

Vibration-Based In-Situ Detection And Quantification Of Delamination In Composite Plates, Hanfei Mei, Asaad Migot, Mohammad Faisal Haider, Roshan Joseph, Md Yeasin Bhuiyan, Victor Giurgiutiu

Faculty Publications

This paper presents a new methodology for detecting and quantifying delamination in composite plates based on the high-frequency local vibration under the excitation of piezoelectric wafer active sensors. Finite-element-method-based numerical simulations and experimental measurements were performed to quantify the size, shape, and depth of the delaminations. Two composite plates with purpose-built delaminations of different sizes and depths were analyzed. In the experiments, ultrasonic C-scan was applied to visualize the simulated delaminations. In this methodology, piezoelectric wafer active sensors were used for the high-frequency excitation with a linear sine wave chirp from 1 to 500 kHz and a scanning laser Doppler …

Vibration-Based In-Situ Detection And Quantification Of Delamination In Composite Plates, Hanfei Mei, Asaad Migot, Mohammad Faisal Haider, Roshan Joseph, Md Yeasin Bhuiyan, Victor Giurgiutiu

Faculty Publications

This paper presents a new methodology for detecting and quantifying delamination in composite plates based on the high-frequency local vibration under the excitation of piezoelectric wafer active sensors. Finite-element-method-based numerical simulations and experimental measurements were performed to quantify the size, shape, and depth of the delaminations. Two composite plates with purpose-built delaminations of different sizes and depths were analyzed. In the experiments, ultrasonic C-scan was applied to visualize the simulated delaminations. In this methodology, piezoelectric wafer active sensors were used for the high-frequency excitation with a linear sine wave chirp from 1 to 500 kHz and a scanning laser Doppler …

Enhanced Carbon Dioxide Electrolysis At Redox Manipulated Interfaces, Wenyuan Wang, Lizhen Gan, John P. Lemmon, Fanglin Chen, John T. S. Irvine, Kui Xie

Faculty Publications

Utilization of carbon dioxide from industrial waste streams offers significant reductions in global carbon dioxide emissions. Solid oxide electrolysis is a highly efficient, high temperature approach that reduces polarization losses and best utilizes process heat; however, the technology is relatively unrefined for currently carbon dioxide electrolysis. In most electrochemical systems, the interface between active components are usually of great importance in determining the performance and lifetime of any energy materials application. Here we report a generic approach of interface engineering to achieve active interfaces at nanoscale by a synergistic control of materials functions and interface architectures. We show that the …

Impact Of Pulse Length On The Accuracy Of Defect Depth Measurements In Pulse Thermography, James Pierce, Nathan B. Crane

Faculty Publications

Pulse thermography is a nondestructive testing method in which an energy pulse is applied to a surface while the surface temperature evolution is measured to detect sub surface defects and estimate their depth. This nondestructive test method was developed on the assumption of instantaneous surface heating, but recent work has shown that relatively long pulses can be used to accurately determine defect depth in polymers. This paper examines the impact of varying input pulse length on the accuracy of defect depth quantification as a function of the material properties. Simulations using both thermoplastics and metals show that measurement error is …

Electrochemical Conversion Of Methane To Ethylene In A Solid Oxide Electrolyer, Changli Zhu, Shisheng Hou, Xiuli Hu, Jinhai Lu, Fanglin Chen, Kui Xie

Faculty Publications

Conversion of methane to ethylene with high yield remains a fundamental challenge due to the low ethylene selectivity, severe carbon deposition and instability of catalysts. Here we demonstrate a conceptually different process of in situ electrochemical oxidation of methane to ethylene in a solid oxide electrolyzer under ambient pressure at 850 °C. The porous electrode scaffold with an in situ-grown metal/oxide interface enhances coking resistance and catalyst stability at high temperatures. The highest C2 product selectivity of 81.2% together with the highest C2 product concentration of 16.7% in output gas (12.1% ethylene and 4.6% ethane) is achieved while the methane …

Controlling The Oxygen Electrocatalysis On Perovskite And Layered Oxide Thin Films For Solid Oxide Fuel Cell Cathodes, Gene Yang, Wonsang Jung, Sung-Jin Ahn, Dongkyu Lee

Faculty Publications

Achieving the fast oxygen reduction reaction (ORR) kinetics at the cathode of solid oxide fuel cells (SOFCs) is indispensable to enhance the efficiency of SOFCs at intermediate temperatures. Mixed ionic and electronic conducting (MIEC) oxides such as ABO₃ perovskites and Ruddlesden-Popper (RP) oxides (A₂BO₄) have been widely used as promising cathode materials owing to their attractive physicochemical properties. In particular, oxides in forms of thin films and heterostructures have enabled significant enhancement in the ORR activity. Therefore, we aim to give a comprehensive overview on the recent development of thin film cathodes of SOFCs. We …

Developable Mechanisms On Developable Surfaces, Todd G. Nelson, Trent K. Zimmerman, Robert J. Lang, Spencer P. Magleby, Larry L. Howell

Faculty Publications

The trend toward smaller mechanism footprints and volumes, while maintaining the ability to perform complex tasks, presents the opportunity for exploration of hypercompact mechanical systems integrated with curved surfaces. Developable surfaces are shapes that a flat sheet can take without tearing or stretching, and they represent a wide range of manufactured surfaces. This work introduces “developable mechanisms” as devices that emerge from or conform to developable surfaces. They are made possible by aligning hinge axes with developable surface ruling lines to enable mobility. Because rigid-link motion depends on the relative orientation of hinge axes and not link geometry, links can …

Influence Of Micro-Structured Superhydrophobic Surfaces On Nucleation And Natural Convection In A Heated Pool, Adam Cowley, Daniel Maynes, Julie Crockett, Brian D. Iverson

Faculty Publications

This word experimentally explores sub-boiling pool nucleation on micro-structured superhydrophobic surfaces. All surfaces tested were submerged in a 20 mm deep pool of water and heated from below to maintain a constant surface temperature, while the side walls of the pool were insulated, and the top was covered. Three thermocouples positioned in the pool obtain the average pool temperature. A heat flux sensor is placed directly beneath the surface to measure the heat flux supplied to the pool. Free convection heat transfer coefficients are obtained for the sub-boiling temperature range of 40 – 90 ºC. Six surface types are studied: …

High-Throughput 3d Reconstruction Of Stochastic Heterogeneous Microstructures In Energy Storage Materials, Yanxiang Zhang, Mufu Yan, Yanhong Wan, Zhenjun Jiao, Yu Chen, Fanglin Chen, Changrong Xia, Meng Ni

Faculty Publications

Stochastic heterogeneous microstructures are widely applied in structural and functional materials, playing a crucial role in determining their performance. X-ray tomography and focused ion beam serial sectioning are frequently used methods to reconstruct three-dimensional (3D) microstructures, yet are demanding techniques and are resolution-limited. Here, a high-throughput multi-stage 3D reconstruction method via distance correlation functions is developed using a single representatively large-sized 2D micrograph for stochastic microstructures, and verified by X-ray micro-tomography datasets of isotropic and anisotropic solid oxide fuel cell electrodes. This method provides an economic, easy-to-use and high-throughput approach for reconstructing stochastic heterogeneous microstructures for energy conversion and storage …

Use Of Flexible Sensor To Characterize Biomechanics Of Canine Skin, Austin Downey, Jin Yan, Eric M. Zellner, Karl H. Kraus, Iris V. Rivero, Simon Laflamme

Faculty Publications

Background Suture materials and techniques are frequently evaluated in ex vivo studies by comparing tensile strengths. However, the direct measurement techniques to obtain the tensile forces in canine skin are not available, and, therefore, the conditions suture lines undergo is unknown. A soft elastomeric capacitor is used to monitor deformation in the skin over time by sensing strain. This sensor was applied to a sample of canine skin to evaluate its capacity to sense strain in the sample while loaded in a dynamic material testing machine. The measured strain of the sensor was compared with the strain measured by the …

Recent Advances In Piezoelectric Wafer Active Sensors For Structural Health Monitoring Applications, Hanfei Mei, Mohammad Faisal Haider, Roshan Prakash Joseph, Asaad Migot, Victor Giurgiutiu

Faculty Publications

In this paper, some recent piezoelectric wafer active sensors (PWAS) progress achieved in our laboratory for active materials and smart structures (LAMSS) at the University of South Carolina: http: //www.me.sc.edu/research/lamss/ group is presented. First, the characterization of the PWAS materials shows that no significant change in the microstructure after exposure to high temperature and nuclear radiation, and the PWAS transducer can be used in harsh environments for structural health monitoring (SHM) applications. Next, PWAS active sensing of various damage types in aluminum and composite structures are explored. PWAS transducers can successfully detect the simulated crack and corrosion damage in aluminum …