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Georgia Tech
1.
McCracken, Michael Thomas.
Fabrication, testing and analysis for non-destructive inspection of bonded composite joints.
Degree: MS, Mechanical Engineering, 2019, Georgia Tech
URL: http://hdl.handle.net/1853/62395 
► Carbon fiber reinforced polymer (CFRP) has risen in usage among many industries including aerospace, automotive, and wind energy. CFRP is used structurally due to its…
(more)
▼ Carbon fiber reinforced polymer (CFRP) has risen in usage among many industries including aerospace, automotive, and wind energy. CFRP is used structurally due to its light weight, corrosion resistance, and mechanical properties. However, there are large differences between CFRP and conventionally used metals. One major issue with using CFRP is creating a reliable bonded joint for joining and repair applications during both manufacturing and services/maintenance. For various reasons, using conventional fasteners is not desirable for creating CFRP joints. Instead, adhesives are widely used to bond CFRP to other materials. Adhesive bonding is not nearly as well understood as conventional fastening. Because adhesives are not well understood, it is difficult to determine how reliable an adhesively bonded joint is. One effective way of assessing the bond reliability is through non-destructive inspection (NDI). There are currently no effective NDI methods available for detecting a “kissing bond,” a bond that has physical contact with the adherend, but very little interfacial strength. Kissing bonds form unexpectedly and can cause a disbond under loads much smaller than expected. In order to study kissing bonds and their detection, these weakened bonds must be reliably fabricated in a controlled environment. In order for NDI detection of kissing bonds to be studied effectively, it must be tested on bonded joints which have been fabricated in a controlled manner. This thesis presents a method of controlled fabrication which can produce reliably strong and weak kissing bonds, specifically for the purpose of NDI research in mind.
Advisors/Committee Members: Ruzzene, Massimo (advisor), Zhang, Chuck (advisor), Ruzzene, Massimo (advisor), Zhang, Chuck (advisor), Wang, Yan (committee member).
Subjects/Keywords: CFRP; NDI; Fabrication; Kissing bond
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APA (6th Edition):
McCracken, M. T. (2019). Fabrication, testing and analysis for non-destructive inspection of bonded composite joints. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62395
Chicago Manual of Style (16th Edition):
McCracken, Michael Thomas. “Fabrication, testing and analysis for non-destructive inspection of bonded composite joints.” 2019. Masters Thesis, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/62395.
MLA Handbook (7th Edition):
McCracken, Michael Thomas. “Fabrication, testing and analysis for non-destructive inspection of bonded composite joints.” 2019. Web. 17 Apr 2021.
Vancouver:
McCracken MT. Fabrication, testing and analysis for non-destructive inspection of bonded composite joints. [Internet] [Masters thesis]. Georgia Tech; 2019. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/62395.
Council of Science Editors:
McCracken MT. Fabrication, testing and analysis for non-destructive inspection of bonded composite joints. [Masters Thesis]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/62395
Georgia Tech
2.
Wen, Yuchen.
Stream of variation and shape control for composite fuselage assembly.
Degree: PhD, Industrial and Systems Engineering, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/62617
► Composite parts have been increasingly used in aerospace industry because of their high strength-to-weight ratio and stiffness-to-weight ratio. Due to the diversity of suppliers and…
(more)
▼ Composite parts have been increasingly used in aerospace industry because of their high strength-to-weight ratio and stiffness-to-weight ratio. Due to the diversity of suppliers and variation in the fabrication process of composite parts, dimensional variability of composite fuselages inevitably exists. One of the critical challenges to reduce the dimensional variability of the assembly process is the complex property of composite materials. The traditional physical models applied to metal materials cannot be directly applied here. It is of high importance to develop systematic methodologies to conduct dimensional analysis, variation reduction, and optimal shape adjustment for the composite fuselages’ assembly process. Based on these motivations, this dissertation focuses on developing systematic methodologies for effective system modeling, quality control and variability reduction in the composite fuselages assembly process. These advanced methodologies enable a better understanding of the composite fuselage structure with actuator applied, a more accurate handling of the fuselage shape control system, and a more precise way to analyze the residual stress during the fuselage assembly process. This dissertation is organized as follows. Chapter 1 introduces a new shape control system with 10 actuators that is able to conduct dimensional shape adjustment before the airplane fuselage assembly process. In Chapter 2, a feasibility study is conducted to evaluate the proposed shape control concept. In the feasibility analysis, an accurate finite element model is developed to mimic the fabrication of composite fuselage, which includes the detailed materials setting, ply design, geometry and fixture structures. The finite element model is validated and calibrated based on physical experimental data with a real fuselage on the production floor. The results show that the single-plane with ten actuators scheme is feasible for shape control, and that actuators do not damage the fuselage. In Chapter 3, a surrogate model considering four types of uncertainties (actuator uncertainty, part uncertainty, modeling uncertainty, and unquantified uncertainty) has been developed for automatic optimal shape control of the system proposed in Chapter 2. A maximum likelihood estimation (MLE) algorithm is used for parameter estimation and response prediction. Afterwards, the surrogated model considering uncertainties is embedded into a feedforward control algorithm, which is achieved by conducting multivariate optimization to minimize the weighted summation of dimensional deviations of the response from the target. We show that the surrogate model considering uncertainties achieves satisfactory prediction performance and the automated optimal shape control system can significantly reduce the assembly cycle time with improved dimensional quality. In Chapter 4, two active learning algorithms are proposed for Gaussian process considering uncertainties, which are the variance-based weighted active learning algorithm and D-optimal weighted active…
Advisors/Committee Members: Shi, Jianjun (advisor), Wang, Ben (committee member), Paynabar, Kamran (committee member), Zhang, Chuck (committee member), Jin, Judy (committee member).
Subjects/Keywords: Finite element analysis; Surrogate model
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APA (6th Edition):
Wen, Y. (2018). Stream of variation and shape control for composite fuselage assembly. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62617
Chicago Manual of Style (16th Edition):
Wen, Yuchen. “Stream of variation and shape control for composite fuselage assembly.” 2018. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/62617.
MLA Handbook (7th Edition):
Wen, Yuchen. “Stream of variation and shape control for composite fuselage assembly.” 2018. Web. 17 Apr 2021.
Vancouver:
Wen Y. Stream of variation and shape control for composite fuselage assembly. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/62617.
Council of Science Editors:
Wen Y. Stream of variation and shape control for composite fuselage assembly. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/62617
Georgia Tech
3.
Shi, Xinran.
Composite index development via data fusion for system monitoring, diagnosis and decision-making.
Degree: PhD, Industrial and Systems Engineering, 2020, Georgia Tech
URL: http://hdl.handle.net/1853/62778
► In a modern multistage manufacturing system, numerous sensors are installed in each manufacturing device, equipment, or station for in-situ, real-time monitoring of the process variables…
(more)
▼ In a modern multistage manufacturing system, numerous sensors are installed in each manufacturing device, equipment, or station for in-situ, real-time monitoring of the process variables and product quality. Though each sensing data plays a central role in the given task, it is desirable to build a composite index to assess the overall performance of the system based on associated sensing information. This thesis proposes methodologies to establish a composite index via data fusion for monitoring, diagnosis, and maintenance decision making in aspects of complex multistage manufacturing systems, which includes (1) A novel composite index to monitor real-time product quality for continuous production of Carbon Nanotube buckypaper. Massive high-dimensional data are collected from the Raman spectroscopy sensor. The obtained spectrum data provide detailed nanostructure information within seconds, which can be decomposed into multiple effects associated with diverse quality characteristics of buckypaper. However, the decomposed effects are still high-dimensional, and a systematic quantification method for buckypaper quality assessment has been lacking. The proposed construction scheme for the composite index integrates penalized mixed-effects decomposition (PMD), weighted cross-correlation, and maximum margin clustering methods, to deliver a single quality index for fast product quality monitoring. (2) A novel automatic analytical framework to streamline the identification procedure of the process variables influencing the quality variable. It is desirable to conduct data analysis to identify the dependency between process variables and the quality variables without the involvement of highly trained data scientists. When coping with potential quality problems of the hot-rolling process, it can automatically identify the prominent process variables. The proposed framework identifies the process variables affecting product quality through feature extraction, clustering, and running permutation tests on multiple types of statistical models. (3) A composite index, termed AvaIlability-Degradation (AID), is proposed for integrating the degradation status of sensing information at the component-levels with the machine availability information at the plant-level. A proactive maintenance plan gives a manufacturer the capability to prolong the life of machinery and prevent the unexpected breakdown of production. However, there are no systematic methodologies to implement the concept in a semiconductor manufacturing system with cluster tools. Towards this end, we have further developed a model for AID integrated optimal proactive maintenance scheduling, which incorporates prognostic and diagnostics information in a three-level proactive maintenance decision-making framework. Additionally, we have validated the proposed strategy with a simulated semiconductor manufacturing process.
Advisors/Committee Members: Shi, Jianjun (advisor), Wang, Ben (committee member), Zhang, Chuck (committee member), Paynabar, Kamran (committee member), Jin, Jionghua (committee member).
Subjects/Keywords: Composite index; Multi-stage manufacturing; Data fusion; Quality assessment; Diagnosis; Maintenance scheduling
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APA (6th Edition):
Shi, X. (2020). Composite index development via data fusion for system monitoring, diagnosis and decision-making. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62778
Chicago Manual of Style (16th Edition):
Shi, Xinran. “Composite index development via data fusion for system monitoring, diagnosis and decision-making.” 2020. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/62778.
MLA Handbook (7th Edition):
Shi, Xinran. “Composite index development via data fusion for system monitoring, diagnosis and decision-making.” 2020. Web. 17 Apr 2021.
Vancouver:
Shi X. Composite index development via data fusion for system monitoring, diagnosis and decision-making. [Internet] [Doctoral dissertation]. Georgia Tech; 2020. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/62778.
Council of Science Editors:
Shi X. Composite index development via data fusion for system monitoring, diagnosis and decision-making. [Doctoral Dissertation]. Georgia Tech; 2020. Available from: http://hdl.handle.net/1853/62778
Georgia Tech
4.
Ebrahimi, Samaneh.
Modeling high dimensional multi-stream data for monitoring and prediction.
Degree: PhD, Industrial and Systems Engineering, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/62198
► This dissertation concentrates on solving problems related to monitoring and predicting high-dimensional, streaming data using new data mining methods. Of the plethora of problems that…
(more)
▼ This dissertation concentrates on solving problems related to monitoring and predicting high-dimensional, streaming data using new data mining methods. Of the plethora of problems that exist, this dissertation attempts to focus on three of them. As a first topic, we propose a new monitoring and diagnosis approach based on PCA for monitoring high-dimensional, multi-stream data. For monitoring, one commonly used method in high dimensions are based on Principal Component Analysis (PCA). For PCA-based monitoring, most of the existing methods focus on PCs with the highest variance. However, we argue that this is an inappropriate approach for the purpose of monitoring. Therefore, we show that adaptively chosen PCs are significantly better for process monitoring. Consequently, we develop a novel monitoring method based on this principle named Adaptive PC Selection (APC). More importantly, we integrate a novel diagnostic approach to enable a streamlined SPC. The PC-based Signal Recovery (PCSR) diagnostics approach draws inspiration from Compressed Sensing to use Adaptive Lasso for identifying the sparse change in the process. We theoretically motivate our approach and do performance evaluation of our integrated Monitoring and Diagnostics method through simulation and case studies. For the second topic, we propose a novel methodology for dynamically monitoring sparse networks. For this, we focus on modeling the network connections in financial institutions. The interconnectedness of financial institutions can function as a mechanism for the propagation and amplification of shocks throughout the economy, thus contributing to financial crises. As such, network analysis has become a critical tool for assessing interconnectedness and systemic risk levels. Hence, we create a monitoring system to detect changes within a sequence of sparse networks constructed from an interbank lending market in the European Union. The approach combines a state space model with the Hurdle model to capture temporal dynamics of the edge formation process, which is modeled as a function of node and edge attributes and estimated using an extended Kalman Filter. Afterwards, Exponential Weighted Moving Average (EWMA) control charts are used to monitor the network sequence in real time in order to distinguish the gradual change resulting from the typical edge dynamics from abrupt changes in trading patterns caused by fundamental changes in market conditions. We find that the proposed methodology would have raised alarms for regulators prior to several key events and announcements by the European Central Bank during the 2007-2009 financial crisis, demonstrating the promise of the approach as an early warning system. In the last topic, we propose a novel deep learning approach for classification of multimedia data. The method is the extension to the Classification Restricted Boltzmann Machine (ClassRBM). The Restricted Boltzmann Machines (RBMs) and Deep Boltzmann Machines (DBMs) methods have been successfully applied for unsupervised learning. A new…
Advisors/Committee Members: Paynabar, Kamran (advisor), Shi, Jianjun (committee member), Gebraeel, Nagi (committee member), Zhang, Chuck (committee member), Mankad, Shawn (committee member).
Subjects/Keywords: Monitoring; High-dimensional; Streaming data; Multimedia; Diagnostics; Networks; Classification; Discriminative learning; Deep learning
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APA (6th Edition):
Ebrahimi, S. (2018). Modeling high dimensional multi-stream data for monitoring and prediction. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62198
Chicago Manual of Style (16th Edition):
Ebrahimi, Samaneh. “Modeling high dimensional multi-stream data for monitoring and prediction.” 2018. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/62198.
MLA Handbook (7th Edition):
Ebrahimi, Samaneh. “Modeling high dimensional multi-stream data for monitoring and prediction.” 2018. Web. 17 Apr 2021.
Vancouver:
Ebrahimi S. Modeling high dimensional multi-stream data for monitoring and prediction. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/62198.
Council of Science Editors:
Ebrahimi S. Modeling high dimensional multi-stream data for monitoring and prediction. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/62198
Georgia Tech
5.
Cai, Fan.
Development of 3-D RF microsystems using additive manufactruing technology.
Degree: PhD, Electrical and Computer Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/58161
► This work intends to explore advanced 3-D integration for state-of-the-art components in wireless systems using various 3-D printing technologies. Several packaging techniques are discussed that…
(more)
▼ This work intends to explore advanced 3-D integration for state-of-the-art components in wireless systems using various 3-D printing technologies. Several packaging techniques are discussed that utilize the inherent benefits of the 3-D printing techniques. The compatible materials of the 3-D printing system are assessed for their large processing format and compatibility with the build-up process. Single layer and multilayer interconnects, transmission lines are investigated at RF and millimeter-wave (mm-wave) to explore the benefits of each in terms of convenience, reliability, cost, and performance. For the first time，the operation frequency fabricated by 3-D printing is up to D band. A novel vertical via interconnect is applied to the integration of state-of-the-art SoP. Additionally, interconnects that route the signal directly from the chip interface to matching networks are implemented on novel flexible organic material PEN are designed. This work also investigates the possible applications for cavity structures where the benefits of 3-D printing can be exploited for highly integrated receiver systems. Active and passive components are incorporated on LCP using a system-on-package approach to improve performance and enhance capability of the antenna. Wire bond interconnects are utilized as a convenient, low-cost packaging solution, ideal for prototype development.
Advisors/Committee Members: Papapolymerou, John (advisor), Cressler, John (committee member), Peterson, Andrew (committee member), Alexopoulos, Christos (committee member), Zhang, Chuck (committee member).
Subjects/Keywords: 3-D printing; Additive manufacturing technology; Microsystems; MM-wave; RF
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APA (6th Edition):
Cai, F. (2016). Development of 3-D RF microsystems using additive manufactruing technology. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58161
Chicago Manual of Style (16th Edition):
Cai, Fan. “Development of 3-D RF microsystems using additive manufactruing technology.” 2016. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/58161.
MLA Handbook (7th Edition):
Cai, Fan. “Development of 3-D RF microsystems using additive manufactruing technology.” 2016. Web. 17 Apr 2021.
Vancouver:
Cai F. Development of 3-D RF microsystems using additive manufactruing technology. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/58161.
Council of Science Editors:
Cai F. Development of 3-D RF microsystems using additive manufactruing technology. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/58161
Georgia Tech
6.
Chien, An-Ting.
Multi-functional PAN based composite fibers.
Degree: PhD, Materials Science and Engineering, 2014, Georgia Tech
URL: http://hdl.handle.net/1853/54304
► Various nano-fillers can introduce specific functions into polymer and expand their application areas. Myriad properties, such as mechanical, electrical, thermal, or magnetic properties can be…
(more)
▼ Various nano-fillers can introduce specific functions into polymer and expand their application areas. Myriad properties, such as mechanical, electrical, thermal, or magnetic properties can be combined with original polymer characteristics, including flexible, light weight, and ease of use. These composites can be used to produce multi-functional fibers as the next generation textile or fabrics. In this research, Polyacrylonitrile (PAN) is adopted as the main polymer with different nano-fillers, such as carbon nanotube (CNT), iron oxide nanoparticle, and graphene oxide nanoribbon (GONR). Using gel-spinning technology, PAN-based composite fibers are fabricated in single- or bi-component fibers. Fibers are also characterized for their structure, morphology, mechanical properties, as well as for their electrical, thermal, or magnetic properties. For example, bi-component fibers with polymer sheath and polymer-CNT core as well as polymer-CNT sheath and polymer core are processed. With electrical and thermal conductivity introduced by CNT, such bi-components fibers can be applied for wearable electronics or for thermal management. Joule-heating effect owing to applied electrical current on single component PAN/CNT fibers is also investigated. With controllable electrical conductivity and fiber temperature, this active functional fiber can be applied for temperature regulation fibers or new carbon fiber manufacturing process. Another example is magnetic fiber with superparamagnetic iron oxide nano-particles. These novel magnetic fibers with high strength can be used for actuator, inductors, EMI shielding, or microwave absorption. GONR is also discussed and used to reinforce PAN-based fibers. Several theoretical models are considered to analyze the observed results.
Advisors/Committee Members: Kumar, Satish (advisor), Griffin, Anselm (committee member), Yao, Donggang (committee member), Zhang, Chuck (committee member), Chae, Hangi (committee member).
Subjects/Keywords: Composites; Polyacrylonitrile; Gel spinning; Bi-component fibers; Carbon nanotube; Graphene; Iron oxide nanoparticle; functional materials; Wearable electronics; Joule heating; Superparamagnetism; Carbon fibers
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APA (6th Edition):
Chien, A. (2014). Multi-functional PAN based composite fibers. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54304
Chicago Manual of Style (16th Edition):
Chien, An-Ting. “Multi-functional PAN based composite fibers.” 2014. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/54304.
MLA Handbook (7th Edition):
Chien, An-Ting. “Multi-functional PAN based composite fibers.” 2014. Web. 17 Apr 2021.
Vancouver:
Chien A. Multi-functional PAN based composite fibers. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/54304.
Council of Science Editors:
Chien A. Multi-functional PAN based composite fibers. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/54304
Georgia Tech
7.
Newcomb, Bradley Allen.
Gel spun PAN and PAN/CNT based carbon fibers: From viscoelastic solution to elastic fiber.
Degree: PhD, Materials Science and Engineering, 2015, Georgia Tech
URL: http://hdl.handle.net/1853/54881
► This study focuses on the processing, structure, and properties of gel spun polyacrylonitrile (PAN) and polyacrylonitrile/carbon nanotube (PAN/CNT) carbon fibers. Gel spun PAN based carbon…
(more)
▼ This study focuses on the processing, structure, and properties of gel spun polyacrylonitrile (PAN) and polyacrylonitrile/carbon nanotube (PAN/CNT) carbon fibers. Gel spun PAN based carbon fibers are manufactured beginning with a study of PAN dissolution in an organic solvent (dimethylformamide, DMF). Homogeneity of the PAN/DMF solution is determined through dynamic shear rheology, and the slope of the Han Plot (log G’ vs log G’’). Solutions were then extruded into gel spun fibers using a 100 filament fiber spinning apparatus in a class 1000 cleanroom. Fibers were then subjected to fiber drawing, stabilization, and carbonization, to convert the PAN precursor fiber into carbon fiber. Carbon fiber tensile strength was shown to scale with the homogeneity of the PAN/DMF solution, as determined by the slope of the log G’ vs log G’’ plot. After the development of the understanding between the homogeneity of the PAN/DMF solutions on the gel spun PAN based carbon fiber tensile properties, the effect of altering the fiber spinning processing conditions on the gel spun PAN based carbon fiber structure and properties is pursued. Cross-sectional shape of the gel spun PAN precursor fiber, characterized with a stereomicroscope, was found to become more circular in cross-section as the gelation bath temperature was increased, the amount of solvent in the gelation bath was increased, and when the solvent was switched from DMF to dimethylacetamide (DMAc). Gel spun fibers were then subjected to fiber drawing, stabilization, and carbonization to manufacture the carbon fiber. Carbon fibers were characterized to determine single filament tensile properties and fiber structure using wide-angle x-ray diffraction (WAXD) and high resolution transmission electron microscopy (HRTEM). It was found that the carbon fiber tensile properties decreased as the carbon fiber circularity increased, as a result of the differences in microstructure of the carbon fiber that result from differences in fiber spinning conditions. In the second half of this study, the addition of CNT into the PAN precursor and carbon fiber is investigated. CNT addition occurs during the solution processing phase, prior to gel spinning. As a first study, Raman spectroscopy is employed to investigate the bundling behavior of the CNT after gel spinning and drawing of the PAN/CNT fibers. By monitoring the peak intensity of the (12,1) chirality in the as-received CNT powder, and in differently processed PAN/CNT fibers, the quality of CNT dispersion can be quickly monitored. PAN/CNT fibers were then subject to single filament straining, with Raman spectra collected as a function of PAN/CNT filament strain. As a result of the PAN/CNT strain, stress induced G’ Raman band shifts were observed in the CNT, indicating successful stress transfer from the surrounding PAN matrix to the dispersed CNT. Utilization of the shear lag theory allows for the calculation of the interfacial shear strength between the PAN and incorporated CNT, which is found to increase as the quality of CNT (higher…
Advisors/Committee Members: Kumar, Satish (advisor), Griffin, Anselm (committee member), Shofner, Meisha (committee member), Yao, Donggang (committee member), Zhang, Chuck (committee member).
Subjects/Keywords: Carbon fiber; Carbon nanotubes
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APA ·
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APA (6th Edition):
Newcomb, B. A. (2015). Gel spun PAN and PAN/CNT based carbon fibers: From viscoelastic solution to elastic fiber. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54881
Chicago Manual of Style (16th Edition):
Newcomb, Bradley Allen. “Gel spun PAN and PAN/CNT based carbon fibers: From viscoelastic solution to elastic fiber.” 2015. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/54881.
MLA Handbook (7th Edition):
Newcomb, Bradley Allen. “Gel spun PAN and PAN/CNT based carbon fibers: From viscoelastic solution to elastic fiber.” 2015. Web. 17 Apr 2021.
Vancouver:
Newcomb BA. Gel spun PAN and PAN/CNT based carbon fibers: From viscoelastic solution to elastic fiber. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/54881.
Council of Science Editors:
Newcomb BA. Gel spun PAN and PAN/CNT based carbon fibers: From viscoelastic solution to elastic fiber. [Doctoral Dissertation]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/54881
Georgia Tech
8.
Lahoti, Geet.
CLUSTERING AND FEATURE DETECTION METHODS FOR HIGH-DIMENSIONAL DATA.
Degree: PhD, Industrial and Systems Engineering, 2019, Georgia Tech
URL: http://hdl.handle.net/1853/63511
► The majority of the real-world data are unlabeled. Moreover, complex characteristics such as high-dimensionality and high variety pose significant analytical challenges. In statistical and machine…
(more)
▼ The majority of the real-world data are unlabeled. Moreover, complex characteristics such as high-dimensionality and high variety pose significant analytical challenges. In statistical and machine learning, supervised and unsupervised methods are used to analyze labeled and unlabeled data, respectively. Compared to supervised learning methods, unsupervised learning is less developed. Therefore, this dissertation focuses on developing unsupervised methods to perform clustering and feature detection tasks in real-world high-dimensional data settings. Specifically, we develop methods to cluster censored spatio-temporal data, detect pixel-level features in medical imaging data, and adaptively detect anomalies in industrial optical inspection images and candidates’ emotions in interview videos. The overarching objective of these methods is to help stakeholders improve the performance of the associated systems in terms of user engagement, patient comfort, customer satisfaction, and product quality.
Advisors/Committee Members: Zhang, Chuck (advisor), Paynabar, Kamran (committee member), Shi, Jianjun (committee member), Wang, Ben (committee member), Qian, Zhen (committee member).
Subjects/Keywords: Statistical Modeling; Machine Learning; Service Systems
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APA (6th Edition):
Lahoti, G. (2019). CLUSTERING AND FEATURE DETECTION METHODS FOR HIGH-DIMENSIONAL DATA. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/63511
Chicago Manual of Style (16th Edition):
Lahoti, Geet. “CLUSTERING AND FEATURE DETECTION METHODS FOR HIGH-DIMENSIONAL DATA.” 2019. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/63511.
MLA Handbook (7th Edition):
Lahoti, Geet. “CLUSTERING AND FEATURE DETECTION METHODS FOR HIGH-DIMENSIONAL DATA.” 2019. Web. 17 Apr 2021.
Vancouver:
Lahoti G. CLUSTERING AND FEATURE DETECTION METHODS FOR HIGH-DIMENSIONAL DATA. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/63511.
Council of Science Editors:
Lahoti G. CLUSTERING AND FEATURE DETECTION METHODS FOR HIGH-DIMENSIONAL DATA. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/63511
Georgia Tech
9.
Taylor, Christine L.
ADHESION EVALUATION AND ASSEMBLY PROCESS DEVELOPMENT FOR PRINTED SILVER INK ON FLEXIBLE SUBSTRATES.
Degree: PhD, Mechanical Engineering, 2019, Georgia Tech
URL: http://hdl.handle.net/1853/64063
► Flexible substrates with printed electronics are being increasingly sought for the widespread and cost-effective use of flexible electronics. With printed ink on flexible substrates, several…
(more)
▼ Flexible substrates with printed electronics are being increasingly sought for the widespread and cost-effective use of flexible electronics. With printed ink on flexible substrates, several items need to be examined: synthesis of ink, deposition of ink, curing of ink, line and spacing of ink, adhesion of ink, fracture strength of ink, electrical characteristics of ink, etc. Among these items, adhesion of ink to the substrate plays an important role in the overall reliability of printed ink on flexible substrate.
In this work, the adhesion and interfacial characteristics of printed conductors were determined though modified shear and peel experimental techniques. Modification to the tests were needed for handling the ink-jet printed films due to manufacturing considerations. (1) These films often are designed to be porous so that the films are more flexible by lower the stiffness. (2) Ink-jetting films often are composed of thin layers that are stacked-up to reach the desired thickness. (3) Depending on the tool and the file conversion to bitmap (or designated file extension) for the printer, the film may show indication of the path taken by the tool head with slight spaces between passes. A numerical model based on sequential crack growth was developed to examine how much the plastic deformation accounts for the experimentally measured peel energy. Lastly, a fully-additive printing process was demonstrated with resistors which resulted in around 6.5 MPa shear strength. For the assemblies, the joint strength of the ink for the joint to traces was stronger than the adhesion strength of the ink to flexible substrate.
Advisors/Committee Members: Sitaraman, Suresh K. (advisor), Harris, Tequilia (committee member), Wang, Yan (committee member), Zhang, Chuck (committee member), Markondeya Raj, Pulugurtha (committee member).
Subjects/Keywords: Adhesion; Printed electronics
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APA (6th Edition):
Taylor, C. L. (2019). ADHESION EVALUATION AND ASSEMBLY PROCESS DEVELOPMENT FOR PRINTED SILVER INK ON FLEXIBLE SUBSTRATES. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/64063
Chicago Manual of Style (16th Edition):
Taylor, Christine L. “ADHESION EVALUATION AND ASSEMBLY PROCESS DEVELOPMENT FOR PRINTED SILVER INK ON FLEXIBLE SUBSTRATES.” 2019. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/64063.
MLA Handbook (7th Edition):
Taylor, Christine L. “ADHESION EVALUATION AND ASSEMBLY PROCESS DEVELOPMENT FOR PRINTED SILVER INK ON FLEXIBLE SUBSTRATES.” 2019. Web. 17 Apr 2021.
Vancouver:
Taylor CL. ADHESION EVALUATION AND ASSEMBLY PROCESS DEVELOPMENT FOR PRINTED SILVER INK ON FLEXIBLE SUBSTRATES. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/64063.
Council of Science Editors:
Taylor CL. ADHESION EVALUATION AND ASSEMBLY PROCESS DEVELOPMENT FOR PRINTED SILVER INK ON FLEXIBLE SUBSTRATES. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/64063
10.
Lyons, Kevin Mark.
Tensile testing and stabilization/carbonization studies of polyacrylonitrile/carbon nanotube composite fibers.
Degree: MS, Materials Science and Engineering, 2012, Georgia Tech
URL: http://hdl.handle.net/1853/45915
► This study focuses on the processing, structure and properties of polyacrylonitrile (PAN)/ carbon nanotube (CNT) composite carbon fibers. Small diameter PAN/CNT based carbon fibers have…
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▼ This study focuses on the processing, structure and properties of polyacrylonitrile (PAN)/ carbon nanotube (CNT) composite carbon fibers. Small diameter PAN/CNT based carbon fibers have been processed using sheath-core and islands-in-a-sea (INS) fiber spinning technology. These methods resulted in carbon fibers with diameters of ~3.5 μm and ~1 μm (for sheath-core and INS respectively). Poly (methyl methacrylate) has been used as the sheath or the sea component, which has been removed prior to carbonization. These fibers have been stabilized and carbonized using a batch process. The effect of stabilization has been characterized by Fourier Transform Infrared Spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC). A non-isothermal extent of cyclization (Mcyc) from the DSC kinetics study was developed in order to obtain an unbiased method for determining the optimal stabilization condition. The results of Mcyc were found to be in good agreement with the experimental FTIR and WAXD observations. The carbon fiber fracture surfaces have been examined using SEM. Various test parameters that affect the tensile properties of the precursor fiber (both PAN and PAN/CNT), as well as carbon fiber have been studied. In an attempt to validate single filament tests, fiber tow testing has also been done using standard test methods. Batch processed carbon fibers obtained via sheath-core geometry exhibited tensile strengths as high as 6.5 GPa, while fibers processed by islands-in-a-sea geometry exhibited strength values as high as 7.7 GPa.
Advisors/Committee Members: Kumar, Satish (Committee Chair), Chae, Han Gi (Committee Member), Griffin, Anselm (Committee Member), Zhang, Chuck (Committee Member).
Subjects/Keywords: Bi-component spinning; Polymer nanocomposites; Polymer; Mechanical properties; Tensile Testing; Polymeric composites; Nanotubes; Carbon fibers
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APA ·
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APA (6th Edition):
Lyons, K. M. (2012). Tensile testing and stabilization/carbonization studies of polyacrylonitrile/carbon nanotube composite fibers. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/45915
Chicago Manual of Style (16th Edition):
Lyons, Kevin Mark. “Tensile testing and stabilization/carbonization studies of polyacrylonitrile/carbon nanotube composite fibers.” 2012. Masters Thesis, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/45915.
MLA Handbook (7th Edition):
Lyons, Kevin Mark. “Tensile testing and stabilization/carbonization studies of polyacrylonitrile/carbon nanotube composite fibers.” 2012. Web. 17 Apr 2021.
Vancouver:
Lyons KM. Tensile testing and stabilization/carbonization studies of polyacrylonitrile/carbon nanotube composite fibers. [Internet] [Masters thesis]. Georgia Tech; 2012. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/45915.
Council of Science Editors:
Lyons KM. Tensile testing and stabilization/carbonization studies of polyacrylonitrile/carbon nanotube composite fibers. [Masters Thesis]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/45915
11.
Mu, Xiaoming.
Photomechanics of polymers and its applications to active structures and additive manufacturing.
Degree: PhD, Mechanical Engineering, 2017, Georgia Tech
URL: http://hdl.handle.net/1853/58706
► Photopolymer is responsive to ultraviolet or visible light and changes its properties for various applications such as actuation, shape morphing and additive manufacturing. Compared to…
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▼ Photopolymer is responsive to ultraviolet or visible light and changes its properties for various applications such as actuation, shape morphing and additive manufacturing. Compared to thermal polymerization, photopolymerization has the similar propagation, termination and chain transfer steps while the initiation step is photoinduced. The objectives of this dissertation research are to study the photomechanics of polymers including light activated polymer and two stage reactive polymer, and explore their applications in photoinduced actuation, material property evolutions, and 3D printing of porous polymers. For the photomechanical study of light activated polymers, a constitutive model based on phase evolution theory is developed to capture the photoinduced stress relaxation. A laminated composite is designed to achieve photo-induced bending in a free-standing state. For two-stage reactive polymers, a photo-thermoviscoelastic model is developed to describe the significant property change during the 2nd stage evolution and the photoinduced viscoelasticity observed in the experiments. Moreover, various photopolymers are mixed with salt particulates to 3D print a polymer-salt composite which can be immersed in water to leach salts and generate pores. Porous polymer structures with 74% porosity can be 3D printed with the advantages of self-supporting, biocompatibility and shape memory effect. The porous parts can be infiltrated by secondary materials to improve the strength or become conductive, and be metalized by electroless nickel plating. In summary, this dissertation presents the study of light interactions with polymers focusing on actuation, property control and 3D printing of functional porous polymer.
Advisors/Committee Members: Qi, Hang Jerry (advisor), Xia, Shuman (committee member), Zhang, Chuck (committee member), Meaud, Julien (committee member), Jacob, Karl (committee member).
Subjects/Keywords: Photomechanics; Active structures; Additive manufacturing
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APA ·
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MLA ·
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Manager
APA (6th Edition):
Mu, X. (2017). Photomechanics of polymers and its applications to active structures and additive manufacturing. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58706
Chicago Manual of Style (16th Edition):
Mu, Xiaoming. “Photomechanics of polymers and its applications to active structures and additive manufacturing.” 2017. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/58706.
MLA Handbook (7th Edition):
Mu, Xiaoming. “Photomechanics of polymers and its applications to active structures and additive manufacturing.” 2017. Web. 17 Apr 2021.
Vancouver:
Mu X. Photomechanics of polymers and its applications to active structures and additive manufacturing. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/58706.
Council of Science Editors:
Mu X. Photomechanics of polymers and its applications to active structures and additive manufacturing. [Doctoral Dissertation]. Georgia Tech; 2017. Available from: http://hdl.handle.net/1853/58706
12.
Yue, Xiaowei.
Engineering-driven data analytics for In situ process monitoring of nanomanufacturing.
Degree: PhD, Industrial and Systems Engineering, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/61625
► Carbon Nanotubes (CNTs) buckypaper is a multifunctional platform material with superior mechanical and electrical characteristics. One of the critical roadblocks to scale-up production of high-quality…
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▼ Carbon Nanotubes (CNTs) buckypaper is a multifunctional platform material with superior mechanical and electrical characteristics. One of the critical roadblocks to scale-up production of high-quality buckypaper is the in situ process monitoring. This dissertation focuses on developing systematic methodologies for effective data analytics and process monitoring of nanomanufacturing. A novel generalized wavelet shrinkage (GWS) method was proposed to realize data denoising and signal enhancement for in-line Raman spectroscopy. A penalized mixed-effects decomposition (PMD) was developed to perform data decomposition and solve the multichannel profile detection problem in nanomanufacturing. We also proposed a novel tensor mixed-effects (TME) model to do high-dimensional data analytics for massive Raman mapping data with complex structure. In addition, different algorithms for parameter estimation were developed for these three approaches. Furthermore, by using numerical simulation and case study, we evaluated the performance of the proposed approaches. The GWS can significantly increase the signal-to-noise ratio as well as improve the accuracy and efficiency of Raman spectroscopy. The PMD lays a solid foundation for monitoring fabrication consistency, uniformity, and defect information, simultaneously. The TME provides us the capability to analyze massive high-dimensional data with mixed effects, and explore the complex correlations. It can be used to quantify the degree of alignment of CNTs buckypaper.
Advisors/Committee Members: Shi, Jianjun (advisor), Wang, Ben (committee member), Paynabar, Kamran (committee member), Zhang, Chuck (committee member), Jin, Jionghua (committee member).
Subjects/Keywords: Data analytics; Nanomanufacturing; Carbon nanotube; Mixed effects; Machine learning
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❌
APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Yue, X. (2018). Engineering-driven data analytics for In situ process monitoring of nanomanufacturing. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/61625
Chicago Manual of Style (16th Edition):
Yue, Xiaowei. “Engineering-driven data analytics for In situ process monitoring of nanomanufacturing.” 2018. Doctoral Dissertation, Georgia Tech. Accessed April 17, 2021.
http://hdl.handle.net/1853/61625.
MLA Handbook (7th Edition):
Yue, Xiaowei. “Engineering-driven data analytics for In situ process monitoring of nanomanufacturing.” 2018. Web. 17 Apr 2021.
Vancouver:
Yue X. Engineering-driven data analytics for In situ process monitoring of nanomanufacturing. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Apr 17].
Available from: http://hdl.handle.net/1853/61625.
Council of Science Editors:
Yue X. Engineering-driven data analytics for In situ process monitoring of nanomanufacturing. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/61625
. 
Open Access Theses and Dissertations
