Engineering Commons^™

Material State Awareness For Composites Part Ii: Precursor Damage Analysis And Quantification Of Degraded Material Properties Using Quantitative Ultrasonic Image Correlation (Quic), Subir Patra, Sourav Banerjee

Faculty Publications

Material state awareness of composites using conventional Nondestructive Evaluation (NDE) method is limited by finding the size and the locations of the cracks and the delamination in a composite structure. To aid the progressive failure models using the slow growth criteria, the awareness of the precursor damage state and quantification of the degraded material properties is necessary, which is challenging using the current NDE methods. To quantify the material state, a new offline NDE method is reported herein. The new method named Quantitative Ultrasonic Image Correlation (QUIC) is devised, where the concept of microcontinuum mechanics is hybrid with the experimentally …

Material State Awareness For Composites Part I: Precursor Damage Analysis Using Ultrasonic Guided Coda Wave Interferometry (Cwi), Subir Patra, Sourav Banerjee

Faculty Publications

Detection of precursor damage followed by the quantification of the degraded material properties could lead to more accurate progressive failure models for composite materials. However, such information is not readily available. In composite materials, the precursor damages—for example matrix cracking, microcracks, voids, interlaminar pre-delamination crack joining matrix cracks, fiber micro-buckling, local fiber breakage, local debonding, etc.—are insensitive to the low-frequency ultrasonic guided-wave-based online nondestructive evaluation (NDE) or Structural Health Monitoring (SHM) (~100–~500 kHz) systems. Overcoming this barrier, in this article, an online ultrasonic technique is proposed using the coda part of the guided wave signal, which is often neglected. Although …

The Effects Of Joule Heating On Electric-Driven Microfluidic Flow, Alexander P. Spitzer

Journal of the South Carolina Academy of Science

This study sought out to more clearly understand the relationship between Joule heating and fluid flow in microfluidic environments, and more specifically, under what circumstances would the fluid flow in the device possibly hinder an experiment being run on it. It had been previous theorised that an electric field may produce turbulence and even vortices within the fluid, which this study attempted to reproduce. Several variables were tested, namely insulating and conducting fluids, higher and lower AC voltages, Newtonian vs. non-Newtonian fluids, and higher and lower DC voltages. A correlation between these variables and turbulent flow was found, with more …

Reconstructing Yeasts Phylogenies And Ancestors From Whole Genome Data, Bing Feng, Yu Ling, Lingxi Zhou, Roufan Xia, Fei Hu, Chao Liu

Faculty Publications

Phylogenetic studies aim to discover evolutionary relationships and histories. These studies are based on similarities of morphological characters and molecular sequences. Currently, widely accepted phylogenetic approaches are based on multiple sequence alignments, which analyze shared gene datasets and concatenate/coalesce these results to a final phylogeny with maximum support. However, these approaches still have limitations, and often have conflicting results with each other. Reconstructing ancestral genomes helps us understand mechanisms and corresponding consequences of evolution. Most existing genome level phylogeny and ancestor reconstruction methods can only process simplified real genome datasets or simulated datasets with identical genome content, unique genome markers, …

Reconstructing Yeasts Phylogenies And Ancestors From Whole Genome Data, Bing Feng, Yu Lin, Lingxi Zhou, Yan Guo, Robert Friedman, Roufan Xia, Chao Liu, Jijun Tang

Faculty Publications

Phylogenetic studies aim to discover evolutionary relationships and histories. These studies are based on similarities of morphological characters and molecular sequences. Currently, widely accepted phylogenetic approaches are based on multiple sequence alignments, which analyze shared gene datasets and concatenate/coalesce these results to a final phylogeny with maximum support. However, these approaches still have limitations, and often have conflicting results with each other. Reconstructing ancestral genomes helps us understand mechanisms and corresponding consequences of evolution. Most existing genome level phylogeny and ancestor reconstruction methods can only process simplified real genome datasets or simulated datasets with identical genome content, unique genome markers, …

Modelling Human Activity Through Structural Vibrations With Alternate Computational Devices To Increase Cost Efficiency, Elaine Patterson

Journal of the South Carolina Academy of Science

Every event that occurs has a reaction, whether it be a pebble causing ripples in a pond or a bullet distressing a wall. Within a structure, these vibrations caused by a specific event in a medium can be measured with an accelerometer, and just as the vibrations caused by a bullet differ observably from those caused by a pebble, vibrations caused by walking vary from those caused by falling, running or jumping. To the eye, these differences are slight to severe, but when that signal is dissected, it is identifiably unique by its cause and location with extensive applications from …

Improving Rolling Bearing Fault Diagnosis By Ds Evidence Theory Based Fusion Model, Xuemei Yao, Shaobo Li, Jianjun Hu

Faculty Publications

Rolling bearing plays an important role in rotating machinery and its working condition directly affects the equipment efficiency. While dozens of methods have been proposed for real-time bearing fault diagnosis and monitoring, the fault classification accuracy of existing algorithms is still not satisfactory. This work presents a novel algorithm fusion model based on principal component analysis and Dempster-Shafer evidence theory for rolling bearing fault diagnosis. It combines the advantages of the learning vector quantization (LVQ) neural network model and the decision tree model. Experiments under three different spinning bearing speeds and two different crack sizes show that our fusion model …

The Aspergillus Flavus Homeobox Gene, Hbx1, Is Required For Development And Aflatoxin Production, Jeffrey W. Cary, Pamela Y. Harris-Coward, Leslie Scharfenstein, Brian M. Mack, Perng-Kuang Chang, Qijian Wei, Matthew Lebar, Carol Carter-Wientjes, Rajtilak Majumdar, Chandrani Mitra, Sourav Banerjee, Anindya Chanda

Faculty Publications

Homeobox proteins, a class of well conserved transcription factors, regulate the expression of targeted genes, especially those involved in development. In filamentous fungi, homeobox genes are required for normal conidiogenesis and fruiting body formation. In the present study, we identified eight homeobox (hbx) genes in the aflatoxin-producing ascomycete, Aspergillus flavus, and determined their respective role in growth, conidiation and sclerotial production. Disruption of seven of the eight genes had little to no effect on fungal growth and development. However, disruption of the homeobox gene AFLA_069100, designated as hbx1, in two morphologically different A. flavus strains, CA14 and AF70, resulted in …

Study Of Ultra Wide Band Gap Alxga1-Xn Field Effect Transistors For Power Electronic Applications, Sakib Mohammed Muhtadi

Theses and Dissertations

High Aluminum content Al_xGa_1-xN (x > 30%) has attracted intense research interest nowadays as “Ultra Wide Band Gap (UWBG)” material due to large band gap (> 3.4 eV). The critical electric field (EC) of UWBG semiconductor AlGaN is significantly higher than GaN. Moreover, electron saturation velocity is also comparable to GaN. These attractive material properties are the needs for getting large breakdown voltage and high thermal stability which are the requirements for next generation power semiconductor devices. Theoretical possibilities show UWBG AlGaN based devices are an emerging class and can outperform conventional GaN based devices even at …

The Shifting Discourse On Third Places: Ideological Implications, Mark N. Wexler, Judy Oberlander

Journal of Ideology

Within the social sciences, literature on third places attempts to assist in the construction of a social concept of “place”. This notion of a place is an idealization of the bridging space with home and family on one side, and work with the rule-based impersonality of life in mass society, on the other. Like the idea of work-life balance—as seen through the vocabulary of placemaking—third places provide people with a place in which there is a balance between the emotive attachments of home and family and the challenge striving for merit and reward in the marketplace. To date, third places …

Improvement Of Phylogenetic Method To Analyze Compositional Heterogeneity, Zehua Zhang, Kecheng Guo, Gaofeng Pan, Jijun Tang, Fei Guo

Faculty Publications

Background: Phylogenetic analysis is a key way to understand current research in the biological processes and detect theory in evolution of natural selection. The evolutionary relationship between species is generally reflected in the form of phylogenetic trees. Many methods for constructing phylogenetic trees, are based on the optimization criteria. We extract the biological data via modeling features, and then compare these characteristics to study the biological evolution between species.

Results: Here, we use maximum likelihood and Bayesian inference method to establish phylogenetic trees; multi-chain Markov chain Monte Carlo sampling method can be used to select optimal phylogenetic tree, resolving local …

Multiphysics Simulation Of Low-Amplitude Acoustic Wave Detection By Piezoelectric Wafer Active Sensors Validated By In-Situ Ae-Fatigue Experiment, Yeasin Bhuiyan, Victor Giurgiutiu

Faculty Publications

Piezoelectric wafer active sensors (PWAS) are commonly used for detecting Lamb waves for structural health monitoring application. However, in most applications of active sensing, the signals are of high-amplitude and easy to detect. In this article, we have shown a new avenue of using the PWAS transducer for detecting the low-amplitude fatigue-crack related acoustic emission (AE) signals. Multiphysics finite element (FE) simulations were performed with two PWAS transducers bonded to the structure. Various configurations of the sensors were studied by using the simulations. One PWAS was placed near to the fatigue-crack and the other one was placed at a certain …

Proton Transfer In Molten Lithium Carbonate: Mechanism And Kinetics By Density Functional Theory Calculations, Xueling Lei, Kevin Huang, Changyong Qin

Faculty Publications

Using static and dynamic density functional theory (DFT) methods with a cluster model of [(Li2CO3)8H]+, the mechanism and kinetics of proton transfer in lithium molten carbonate (MC) were investigated. The migration of proton prefers an inter-carbonate pathway with an energy barrier of 8.0 kcal/mol at the B3LYP/6-31 G(d,p) level, which is in good agreement with the value of 7.6 kcal/mol and 7.5 kcal/mol from experiment and FPMD simulation, respectively. At transition state (TS), a linkage of O–H–O involving O 2p and H 1 s orbitals is formed between two carbonate ions. The calculated trajectory of H indicates that proton has …

Spatial Variation Analysis For Measured Indoor Massive Mimo Channels, Qi Wang, Bo Ai, David W. Matolak, Ruisi He, Ke Guan, Zhangdui Zhong, Dapeng Li

Faculty Publications

As one of the most important candidate technologies for the fifth-generation wireless communication systems, massive MIMO technology has been widely studied recently because of the significant improvements it can provide in terms of spectrum efficiency and power efficiency. As the foundation of wireless communication, research on propagation characteristics for massive MIMO channels is of primary importance. This paper investigates the characteristics for massive MIMO channels in an indoor hall scenario at 6-GHz. Channel measurements were conducted with a bandwidth of 200 MHz in both line of sight (LOS) and non-LOS (NLOS) conditions. The statistical parameters in the delay domain were …

Static And Dynamic Strain Monitoring Of Reinforced Concrete Components Through Embedded Carbon Nanotube Cement-Based Sensors, Antonella D’Alessandro, Filippo Ubertini, Enrique García-Macías, Rafael Castro-Triguero, Austin Downey, Simon Laflamme, Andrea Meoni, Annibale Luigi Materazzi

Faculty Publications

The paper presents a study on the use of cement-based sensors doped with carbon nanotubes as embedded smart sensors for static and dynamic strain monitoring of reinforced concrete (RC) elements. Such novel sensors can be used for the monitoring of civil infrastructures. Because they are fabricated from a structural material and are easy to utilize, these sensors can be integrated into structural elements for monitoring of different types of constructions during their service life. Despite the scientific attention that such sensors have received in recent years, further research is needed to understand (i) the repeatability and accuracy of sensors’ behavior …

An Ameliorated Prediction Of Drug–Target Interactions Based On Multi-Scale Discrete Wavelet Transform And Network Features, Cong Shen, Yijie Ding, Jijun Tang, Xinying Xu, Fei Guo

Faculty Publications

The prediction of drug–target interactions (DTIs) via computational technology plays a crucial role in reducing the experimental cost. A variety of state-of-the-art methods have been proposed to improve the accuracy of DTI predictions. In this paper, we propose a kind of drug–target interactions predictor adopting multi-scale discrete wavelet transform and network features (named as DAWN) in order to solve the DTIs prediction problem. We encode the drug molecule by a substructure fingerprint with a dictionary of substructure patterns. Simultaneously, we apply the discrete wavelet transform (DWT) to extract features from target sequences. Then, we concatenate and normalize the target, drug, …

An Ensemble Deep Convolutional Neural Network Model With Improved D-S Evidence Fusion For Bearing Fault Diagnosis, Shaobo Li, Guoka Liu, Xianghong Tang, Jianguang Lu, Jianjun Hu

Faculty Publications

Intelligent machine health monitoring and fault diagnosis are becoming increasingly important for modern manufacturing industries. Current fault diagnosis approaches mostly depend on expert-designed features for building prediction models. In this paper, we proposed IDSCNN, a novel bearing fault diagnosis algorithm based on ensemble deep convolutional neural networks and an improved Dempster–Shafer theory based evidence fusion. The convolutional neural networks take the root mean square (RMS) maps from the FFT (Fast Fourier Transformation) features of the vibration signals from two sensors as inputs. The improved D-S evidence theory is implemented via distance matrix from evidences and modified Gini Index. Extensive evaluations …

An Ensemble Deep Convolutional Neural Network Model With Improved D-S Evidence Fusion For Bearing Fault Diagnosis, Shaobo Li, Guokai Liu, Xianghong Tang, Jianguang Lu, Jianjun Hu

Faculty Publications

Intelligent machine health monitoring and fault diagnosis are becoming increasingly important for modern manufacturing industries. Current fault diagnosis approaches mostly depend on expert-designed features for building prediction models. In this paper, we proposed IDSCNN, a novel bearing fault diagnosis algorithm based on ensemble deep convolutional neural networks and an improved Dempster–Shafer theory based evidence fusion. The convolutional neural networks take the root mean square (RMS) maps from the FFT (Fast Fourier Transformation) features of the vibration signals from two sensors as inputs. The improved D-S evidence theory is implemented via distance matrix from evidences and modified Gini Index. Extensive evaluations …

An Advanced Multi-Sensor Acousto-Ultrasonic Structural Health Monitoring System: Development And Aerospace Demonstration, Joel Smithard, Nik Rajic, Stephen Van Der Velden, Patrick Norman, Cedric Rosalie, Steve Galea, Hanfei Mei, Bin Lin, Victor Giurgiutiu

Faculty Publications

A key longstanding objective of the Structural Health Monitoring (SHM) research community is to enable the embedment of SHM systems in high value assets like aircraft to provide on-demand damage detection and evaluation. As against traditional non-destructive inspection hardware, embedded SHM systems must be compact, lightweight, low-power and sufficiently robust to survive exposure to severe in-flight operating conditions. Typical Commercial-Off-The-Shelf (COTS) systems can be bulky, costly and are often inflexible in their configuration and/or scalability, which militates against in-service deployment. Advances in electronics have resulted in ever smaller, cheaper and more reliable components that facilitate the development of compact and …

Investigation Of Mimo Channel Characteristics In A Twosection Tunnel At 1.4725 Ghz, Rongchen Sun, David W. Matolak, Cheng Tao, Liu Liu, Zhenhui Tan, Tao Zhou

Faculty Publications

This paper presents results from a wide band single-input–single-output (SISO) and 16 16 virtual multiple-input–multiple-output (MIMO) measurement campaign at a center frequency of 1.4725 GHz in a 100-meter long tunnel laboratory which is terminated by a vertical wall with a metallic door. The path loss, root-mean-square delay spread (RMS-DS) characteristics, and power delay profiles (PDPs) are described. In addition, we provide results for the MIMO channel amplitude matrix, which offers a new perspective in understanding MIMO characteristics in tunnel scenarios. Our measurement results are analyzed and compared to ray tracing simulations. The relationships among the angle spread, channel matrix singular …

Road Accidents Bigdata Mining And Visualization Using Support Vector Machines, Usha Lokala, Srinivas Nowduri, Prabhakar K Sharma

Publications

Useful information has been extracted from the road accident data in United Kingdom (UK), using data analytics method, for avoiding possible accidents in rural and urban areas. This analysis make use of several methodologies such as data integration, support vector machines (SVM), correlation machines and multinomial goodness. The entire datasets have been imported from the traffic department of UK with due permission. The information extracted from these huge datasets forms a basis for several predictions, which in turn avoid unnecessary memory lapses. Since data is expected to grow continuously over a period of time, this work primarily proposes a new …

Children's Law Center Site Redevelopment, Caroline Olivia Haggard, Javonte Isaac, Joshua Joslin, E'Lexus Nelson, Ana Vieira, Adrien Williams, David Zalla

Senior Theses

Soda City Engineering and Consulting was contracted by the USC School of Law to redevelop the Children’s Law Center site in Columbia, SC. Currently, the site does not comply with current standards and specifications. The objective of this project is to completely redevelop the site with a new annex building and ensuring everything is up to code, while still allowing the historic structure to maintain its use throughout construction.

Dynamic Model And Control Of Quadrotor In The Presence Of Uncertainties, Courage Agho

Theses and Dissertations

This thesis considers the control of quadrotor using a linear PID control and ℒ1 adaptive control. In a justifiable concept, PID controller can be used to control a quadrotor, but in the presence of uncertainties or disturbance, the quadrotor can’t be automatically adjusted to control the changing dynamics of the quadrotor. To solve the problem associated with uncertainties, various control methodology can be used for controlling the changing dynamic of quadrotor, but in this thesis, ℒ1 adaptive control is used because it allows for fast and robust adaptation for desired transient performance in the presence of matched and unmatched uncertainties. …

Multidisciplinary Shape Optimization Of A Composite Blended Wing Body Aircraft, Charles Maxwell Boozer

Theses and Dissertations

A multidisciplinary shape optimization tool coupling aerodynamics, structure, and performance was developed for battery powered aircraft. Utilizing high-fidelity computational fluid dynamics analysis tools and a structural wing weight tool, coupled based on the multidisciplinary feasible optimization architecture; aircraft geometry is modified in the optimization of the aircraft’s range or endurance. The developed tool is applied to three geometries: a hybrid blended wing body, delta wing UAS, the ONERA M6 wing, and a modified ONERA M6 wing. First, the optimization problem is presented with the objective function, constraints, and design vector. Next, the tool’s architecture and the analysis tools that are …

Evaluation And Modeling Of The Different Material Properties Of The Captive And Wild Diets Of Carnivores, Jill Den Outer, Bethany Janos, Elizabeth Mccourt, William Molair

Senior Theses

Specific to captive BFFs, the most significant changes in cranial morphology are related to an increase in zygomatic arch width. The zygomatic arch region is the area along which the masseter muscle (a critical muscle of mastication for carnivores) is stretched3 . Mechanical stability of muscular tissues has been shown to be closely related to the structural integrity of the surrounding bones. In mice, mechanical unloading of the hind legs has been shown to induce muscular atrophy, which led to increased porosity and fragmentation in the femur and tibia4. As less force is required for a captive ferret to fully …

Beer, Booze, And Biofuels: An Introduction To Chemical Engineering, Kayla Revelle, Jacob Lambert, Kelly Kopchak

Senior Theses

The goal of this thesis project was to provide the layout, curriculum, and scheduling for an introductory course regarding chemical engineering for non-majors. Throughout the course of our studies in chemical engineering and engineering in general it had come to our attention that there were many myths regarding the classes and curriculum. We had heard countless times things such as “I am glad I’m not an engineering major”, “those classes seem so hard and boring”, or “It’s all math”. The purpose of this project and class was to dispel those myths and show non-majors what chemical engineering is all about. …

Bird's Eye View: Cooperative Exploration By Ugv And Uav, Shannon Hood

Theses and Dissertations

This paper proposes a solution to the problem of cooperative exploration using an Unmanned Ground Vehicle (UGV) and an Unmanned Aerial Vehicle (UAV). More specifically, the UGV navigates through the free space, and the UAV provides enhanced situational awareness via its higher vantage point. The motivating application is search and rescue in a damaged building. A camera atop the UGV is used to track a fiducial tag on the underside of the UAV, allowing the UAV to maintain a fixed pose relative to the UGV. Furthermore, the UAV uses its front facing camera to provide a birds-eye-view to the remote …

Cost And Fuel Usage Optimization Of Activating Solution Based Silica Fume Geopolymer Concrete, Lateef Najeh Assi

Theses and Dissertations

Development of sustainable construction materials has been the focus of research efforts worldwide in recent years. Concrete is a major construction material; hence, finding alternatives to ordinary Portland cement is of extreme importance due to high levels of carbon dioxide emissions associated with its manufacturing process. Geopolymer concrete is a potential solution; however, concerns about the high cost and the low real fuel energy efficiency are obstacles against its increase in the market share.

In this thesis, the current cost and fuel (thermal energy) usage are calculated. In addition, the cost and fuel usage were optimized based on previous experimental …

Low Bandwidth Communication For Networked Power Hardware-In-The-Loop Simulation, Sean Borgsteede

Theses and Dissertations

Power-Hardware-In-the-Loop (PHIL) simulations allow the design and validation of power hardware components in virtual power system schemas with near real-time operation. This technique is increasingly used in the development cycle of many products to reduce design costs and increase design fidelity. The Hardware under Test (HuT) interfaces with a simulation of the user’s choosing through a hardware interface (HI). The digitally simulated system (DSS) runs on the real-time simulator before sending a reference value to the hardware interface to enforce. In this virtual to real interface, closed-loop stability and the simulation accuracy are the two paramount criteria in regards to …

Physical Characterization Of Electrodeposited Pcb Copper Foil Surfaces, Blessing Kolawole Ojo

Theses and Dissertations

Given that data rates of computers is on the rise and optimization of bus speeds continue to be of importance in improving the system performance, different models for a prediction of the impact of the surface roughness of copper foil have been developed and incorporated into different software’s and applications used by design engineers.

With different models known to have been created for characterization of electrodeposited copper, they have been mostly affected by the need for higher frequencies as they are mostly useful for prediction at frequency of a few GHz. With the introduction of a new model (known as …