Mechanical Engineering Commons^™

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 …

Study Of Wire Arc Additive Manufacturing With Aluminum Alloy 2219, Sritam Kumar Dash

Theses and Dissertations

This thesis discusses WAAM (wire arc additive manufacturing) technology using TIG (Tungsten Inert Gas) welding method with aluminum 2219 as the substrate and aluminum 2319 as the filler material. The most important characteristic of this method of manufacturing is very little wastage of material as it does not follow the conventional method of manufacturing where material is removed from a bigger block to finally achieve the desired shape. This method uses a layer by layer approach to build the part. Generally, in additive manufacturing, the production time may vary depending on the type of method used. The material deposition rate …

Enhanced Heat Transfer In Spray Cooling Through Surface Modifications: An Experimental And Computational Study, Azzam Saadi Salman

Theses and Dissertations

Today, dissipating high heat flux safely is one of the greatest challenges for thermal engineers in thermal management systems, and it becomes a critical barrier to technological developments for many engineering applications. Due to technological advances and aggressive micro-miniaturization of electronic components, the surface area of most devices has shrunk while the computational power increased exponentially. Therefore, the amount of heat dissipated from surfaces has increased significantly. Numerous cooling techniques have been introduced to replace the traditional air cooling systems and to maintain the efficiency and reliability of electronic components. Microelectronics work efficiently and safely at surface temperatures of < 100 ℃ and 125 ℃ for general and defense applications, respectively. One of the proposed alternative schemes is spray cooling, which is considered one of the most advanced cooling methods. It is used for high and ultra-high heat flux dissipation, as it can dissipate 150-200 W/cm2 while maintaining the surface temperature within this range. Also, spray cooling removes a large amount of energy at a lower liquid flow rate compared to other cooling techniques, such as jet impingement and microchannel heat sink. The thermal performance of spray cooling systems can be enhanced either actively or passively. Active enhancement is a very efficient technique; however, it adds more pumping power. The present work focuses on three main objectives: evaluating and analyzing spray cooling performance, developing a three-dimensional numerical multi-phase model for heat transfer process in spray cooling and enhancing the thermal performance of spray cooling passively.

First, …

Computational Wave Field Modeling In Anisotropic Media, Sajan Shrestha

Theses and Dissertations

In this thesis, a meshless semi-analytical computational method is presented to compute the ultrasonic wave field in generalized anisotropic material while understanding the physics of wave propagation in detail. To understand the wave-damage interaction in an anisotropic material, it is neither feasible nor cost-effective to perform multiple experiments in the laboratory. Hence, recently the computational nondestructive evaluation (CNDE) received much attention to performing the NDE experiments in a virtual environment. In this thesis, a fundamental framework is constructed to perform the CNDE experiment of a thick composite specimen in a Pulse-Echo (PE) and through-transmission mode. To achieve the target, the …

Using A Nondispersive Wave Propagation For Measuring Dynamic Fracture Initiation Toughness Of Materials: Experimental And Numerical Based Study, Ali Fahad Fahem

Theses and Dissertations

Fracture mechanics has been a subject of great interest in the engineering community for decades. During this period, fracture parameters such as Stress Intensity Factor (SIF), J-integral, and Crack-Tip Opening Displacement (CTOD) have been developed and used to characterize the fracture properties of most engineering materials under quasi-static loading condition. Usually, these properties are obtained experimentally by using standard methods such as ASTM E399, E1820 or E1920 to evaluate the stress intensity factor ������ ������������, elastic-plastic toughness ������ ������������ and crack tip opening displacement (CTOD) respectively. Conversely, most critical engineering applications are subjected to a sudden or high strain rate …

Quantification Of Material Degradation For Material State Awareness Of Composite Materials., Vahid Tavaf

Theses and Dissertations

The objectives of this research are to develop a comprehensive method to quantify the material degradation of composite materials in the presence of distributed damages and predict the failure in the defected composites using the updated effective material properties. Defects can grow in composites at the macro scale caused by the microscale voids, matrix cracks, fiber breakages starting from manufacturing processes to the high and low cycle fatigue loads, high temperature, and high humidity during operation. Hence, to predict a more realistic failure model, it is necessary to consider the repercussions of degraded materials. The proposed research work is divided …

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 …

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 …

Surrogate Formulation Based On Chemical Functional Group Analysis, Stuart Nates

Theses and Dissertations

Chemical kinetic characteristics of real fuels exhibit high-dimensional complexity due to the excessive number of molecules and molecular classes. As a method of projecting this high-dimensional complexity, which is pertinent to real fuels, to the low-dimensional description, either a surrogate approach or detailed experiments have been utilized, can guide the construction of chemical kinetic models for real fuel. Although the validity of the surrogate approach has been extensively demonstrated by a wide range of canonical experiments for whole fuel/air mixtures, the use of empirical fuel property indicators still worries whether or not the surrogate mixture truly captures the more complex …

A Model For Condensation Heat Transfer In Hydrophobic-­Hydrophilic Surfaces, Abdulwahab E. Alhashem

Theses and Dissertations

The primary focus of this research is to provide a validated model for a comprehensive understanding of hydrophobic-­‐hydrophilic condensation on patterned-­‐ hybrid surface. Establishing the model requires the modeling of fully dropwise condensation (DWC) before applying modifications to evaluate heat transfer performance of patterned-­‐hybrid condensation surface.

The model for fully DWC consists of defining expressions for heat transfer through a single drop, maximum radius of the drop and drop-­‐size distribution which all are primarily based on the work in the literature. In this work the author utilized a proposed modified version of the simulation for drop-­‐size distribution for fully DWC, …

Impact Of Cycloalkanes On Ignition Propensity Measured As Derived Cetane Number In Multi-Component Surrogate Mixtures, Dalton Odell Carpenter

Theses and Dissertations

Cycloalkanes are one type of hydrocarbons present in real jet fuels. The distinct cyclic structure of the cyclo-alkanes impacts the chemical kinetic behavior differently compared to n- and iso-alkanes. At high temperatures, thermal decomposition reactions dominate, producing n-alkyl radicals similar to the oxidation reactions of n-alkanes thus promoting the reactivity. Whereas in low temperatures, the presence of the ring structure essentially suppresses the formation of alkylhydroperoxy radicals (QOOH) from alkylperoxy radicals (RO2), thus exhibiting similar reactivity to iso-alkanes. In previous generations of surrogate fuels, the cyclo-alkane functional group were largely ignored due to low levels of cycloalkanes in traditional jet …

Enhancing Thermal-Hydraulic Performance Of Parallel And Counter Flow Mini-Channel Heat Sinks Utilizing Secondary Flow: A Numerical And Experimental Study, Amitav Tikadar

Theses and Dissertations

Continual growth of hydraulic and thermal boundary layers along stream wise direction in conventional straight fin mini-channel heat sink causes gradual deterioration of their thermal performance. To enhance thermal-hydraulic performance by breaking and redevelopment of the boundary layers, this research aims to introduce a novel inter-connected mini-channel sinks. Two inter-connectors were positioned transversely between two adjacent mini-channels, which segmented the flow domain into three zones. Secondary flow was generated through the inter-connectors utilizing the pressure difference of the adjacent channels resulting in hydraulic and thermal boundary layers disruption and hence enhanced thermal-hydraulic performance of the mini-channel heat sink was achieved. …

3d Topology Optimization Of Spatially Reinforced Composites, Luis G. Bahamonde Jácome

Theses and Dissertations

Topology optimization is a numerical design tool used to generate structural concepts that present optimal load paths for a given set of functional requirements. This functional generative design capability has been used to lightweight high performance structures with 1D, 2D and 3D stress states. On the other hand, fiber-reinforced composites are the perfect candidate material to use in high performance structures due to the tailorability of their stiffness and strength properties. Although numerical tools that simultaneously tailor the composite material properties while optimizing the structural topology exist, these tools are inherently limited to 1D and 2D stress states.

This work …

Mechanical Characterization And Non-Destructive Evaluation Of SicF/SicM Composites For Nuclear Applications, Donald J. Mccleeary

Theses and Dissertations

The SiC_f/SiC_m composite material is a promising candidate for accident tolerant fuel cladding in light water reactors and for structural elements in high temperature reactors. The material demonstrates exceptional toughness when compared to monolithic ceramics. It is critical to characterize the mechanical behavior, internal damage and ultimate strength of these composites under relevant loading conditions. In this thesis, the author developed and improved several mechanical characterization and non-destructive evaluation methods and applied them to SiC_f/SiC_m composites. Impulse excitation (IE) analysis of damaged SiC_f/SiC_m composite disks following controlled impact testing shows a …

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 …

Acoustoelastic Metamaterial With Simultaneous Noise Filtering And Energy Harvesting Capability From Ambient Vibrations, Fariha Mir

Theses and Dissertations

Harvesting unused and untapped energy from ambient vibration noise and acoustic sound waves is an emerging field of research in the recent years. Utilization of the energy with a wide band of the frequency spectrum from the vibrational sources alone stands as one of the most promising ways to power small electronic devices, smartphones, local structural health monitoring (SHM) sensors and home and workshop appliances. Various sources of ambient vibration and acoustic noise can be found around us in our everyday life. These sources are abundant in almost all the engineering industries and manufacturing facilities for example in aerospace, mechanical …

Plasma Surface Functionalization Of Afp Manufactured Composites For Improved Adhesive Bond Performance, Ibrahim Sarikaya

Theses and Dissertations

High-performance composite structures not only require a reliable fabrication process when creating primary structures, but also a high fidelity and repeatable bonding process for the assembled components. During the assembly process, surface contaminants are a major concern as they have the potential to compromise the bond quality resulting in poor bond strength, low failure load, and undesirable failure modes of the adhesively bonded structures. This is further complicated by composite materials inherently possessing low surface energy and thus exhibiting low adhesive property. Therefore, detecting and removing contaminants on the pre-bond composite surface is an active research topic in pursuit of …

Surface Science And Engineering Of Nano-Structured Cathodes For Intermediate Temperature Solid Oxide Fuel Cells, Yeting Wen

Theses and Dissertations

The bulk-to-surface Sr-segregation can seriously compromise the stability of oxygen electrocatalysis in Sr-doped perovskite oxides such as La1-xSrxCoO3-δ and La1-xSrxCo1- yFeyO3-δ and limit their practical applications as cathode materials in solid oxide fuel cells. Although such chemical instability has been actively studied in recent years, fundamental understanding of Sr-segregation process vs temperature and time, particularly under real-world conditions, as well as the suppression method, are still needed. This PhD dissertation aims to acquire fundamental knowledge of Sr-segregation process under practical conditions in solid oxide fuel cells and develop suppression method to ensure the long-term stability through surface modifications.

To gain …

Cpu Cooling Pulse Device For Enhanced Heat Transfer, Hannah Farabee, Noémie L. Iñiguez, Hugo Nunez, Wendy Zwanka

Senior Theses

Ice Dragon Cooling is a company which researches thermofluids and heat transfer technologies. The company’s present research focuses on HVAC and computer applications, with an emphasis on nanofluid development. To support Ice Dragon’s mission, the company wants a product that enhances heat transfer efficiency in liquid-cooled CPU systems. The product is to be a pulse device which increases the turbulence of a liquid across a computer CPU cooling block, thereby expediting heat transfer away from the CPU.

The needs for Ice Dragon Cooling were determined based on engineering knowledge and industry consultation. After further analysis, it was determined that increasing …

Structural Health Monitoring And Non-Destructive Inspection Of Composite And Metallic Structures, Asaad Qasim Migot

Theses and Dissertations

Structural Health Monitoring (SHM) and Nondestructive Testing (NDT) techniques are being used as effective tools for investigating variety of civil, mechanical, and aerospace applications. In recent years, these techniques become such incredible tools for continuously monitoring of various structures. The aim of the dissertation work is to develop SHM and NDT methodologies for acoustic emission sources localization, damage detection and quantification in metallic and composite structures using a network of sensors, guided wave and developed imaging methods. This work is implemented through preparing metallic and composite specimens, setting up experiments, designing efficient networks of sensors, modeling guided wave interaction with …

Numerical Analysis On Convective Cooling Augmented By Evaporative Heat And Mass Transfer For Thermal Power Plant Application, Sudipta Saha

Theses and Dissertations

This thesis work describes a numerical study on the effect of evaporative cooling on the augmentation of forced convective cooling. In recent years, on-demand phase change boosted cooling has drawn major interest where convective heat transfer is augmented/aided by evaporative heat and mass transport processes. This dual mode (convection and evaporation) cooling method is envisioned to drastically enhance the heat transfer coefficient where conventional convective cooling has already reached its maximum value and furthermore dry cooling is still a desired objective. A multi- dimensional mathematical model has been developed to conduct simulations over a range of operating parameters to obtain …