Engineering Commons^™

Fate And Transport Of The Microbiome In Built Environments, Dahae Seong

Theses and Dissertations

Buildings are complex ecosystems evolving continuously. Indoor components such as occupants, ventilation system, and building structures influence the microbiome. To shed light on how the microbial population in a building will respond to such a fluid system, the fundamental interactions between microbes and the indoor ecosystem must be understood. Buildings are being designed as air-tight structures to save energy; however, this could lead to degradation of indoor air quality through indoor sources of contaminants and/or containment of pollutants in the room or introduce outdoor pollutants indoors depending on the ventilation conditions. In addition, transmission of infectious microbes in indoors threaten …

Shape-Selective Silver Catalysts For Ethylene Epoxidation, Kaveh Shariati

Theses and Dissertations

Epoxidation of ethylene with oxygen over promoted silver catalyst is one of the most important examples of heterogeneous catalysis to date with a multi-billion dollar annual market. Ethylene oxide (EO) can be used directly as a sterilizer, disinfectant, and fungicide, or as an intermediate chemical for producing ethylene glycol, detergents, antifreeze, polyesters, as well as a variety of other commercial chemicals. Thus, ethylene oxide is known as one of the highest volume chemicals produced in the chemical industry, accounting for approximately 40-50% of the total value of organic chemicals produced by heterogeneous oxidation. Considering the application of EO in detergents …

Multi-Fidelity Surrogate And Reduced-Order Model-Based Microfluidic Concentration Gradient Generator Design, Haizhou Yang

Theses and Dissertations

The microfluidic concentration gradient generator (μCGG) is an important device to generate and maintain concentration gradients (CGs) of biomolecules for understanding and controlling biological processes. However, determining the optimal operating parameters of μCGG is still a significant challenge, especially for complex CGs in cascaded networks. To tackle such a challenge, this study presents multi-fidelity surrogate and reduced-order model-based optimization methodologies for accurate and computationally efficient design of μCGGs.

The surrogate-based optimization (SBO) method is first proposed for the design optimization of μCGGs based on an efficient physics-based component model (PBCM). Various combinations of regression and correlation functions in Kriging and …

Quantifying And Elucidating The Effect Of Co2 On Aemfcs, Yiwei Zheng

Theses and Dissertations

Anion exchange membrane fuel cells (AEMFCs) have recently received significant attention as a future high efficiency, environmentally friendly energy conversion device. This attention is due to the potential advantages that AEMFCs can offer compared the much more common, and commercialized, proton exchange membrane fuel cells (PEMFCs) – most notably lower cost. However, there are several remaining roadblocks for the AEMFC technology to be widely adopted, such as: i) the stability of the anion exchange membranes (AEMs) and anion exchange ionomer (AEIs); ii) the development of highly active catalysts with either low platinum group metal (PGM) loading or catalysts that are …

Unsupervised Learning For Anomaly Detection In Remote Sensing Imagery, Husam A. Alfergani

Theses and Dissertations

Landfill fire is a potential hazard of waste mismanagement, and could occur both on and below the surface of active and closed sites. Timely identification of temperature anomalies is critical in monitoring and detecting landfill fires, to issue warnings that can help extinguish fires at early stages. The overarching objective of this research is to demonstrate the applicability and advantages of remote sensing data, coupled with machine learning techniques, to identify landfill thermal states that can lead to fire, in the absence of onsite observations. This dissertation proposed unsupervised learning techniques, notably variational auto-encoders (VAEs), to identify temperature anomalies from …

Investigation Of Distracted Driving Events In New Jersey, Ahmed Sajid Hasan

Theses and Dissertations

Every year, thousands of people die in the United States due to crashes involving distracted driving, with this cause contributing to 25% of all fatal traffic crashes in New Jersey in particular. Over the past several years, various techniques (e.g., surveys, crash reports, videos, and simulations) were developed and implemented by the transportation safety community to identify and evaluate distracted driving events. However, these methods collect cross-sectional data on individual subjects and do not provide the actual number of distractions on the road. To fill this gap, this study collected longitudinal data on distracted driving events in the state of …

Delivery Optimization And Evaluation Of Biomechanics Of An Injectable Nucleus Pulposus Replacement Device, Zachary Rustin Brown

Theses and Dissertations

Lower back pain effects up to 80% of people at some point in their life, a majority of cases being the result of degenerative disc disease. Treatment options for degenerative disc disease are limited, jumping from physical therapy to major spinal fusion and total disc replacement surgery with little to no approaches in between. Furthermore, surgical treatments have not shown to be more effective than conservative treatments and reducing pain and disability over the long term. Hydrogels have shown promise as a potential nucleus pulposus replacement device. Their properties are controllable and can be implanted into the body through minimally …

Mechanical And Material Characterization Of Advanced Materials For Tissue Regeneration, Bailey Kylara Ricketts Jackson

Theses and Dissertations

In natural disasters and military deployment operations, injury to long bone can cause extensive damage and be difficult to treat and heal quickly. Explosive devices and trauma often produce long-bone (>2-cm length) wounds that are more complicated than common fractures. Due to the size and complexity of these injuries, they can be difficult to treat in a battlefield environment and take a long time to heal completely and properly. Even after the long healing period, these injuries often require rehabilitation to strengthen the muscles that have weakened in the wounded limb. For military applications especially, these effects can put …

Fabrication And Comparative Study Of Horizontal And Vertical Electrospun Protein-Polysaccharide Nanofiber Biomaterials, Ashley Rivera-Galleti

Theses and Dissertations

The use of biocompatible and biodegradable composite materials for biomedical applications has attracted the attention of many researchers in the past few years. In this study, we fabricated nanofibers of silk fibroin and cellulose and its derivatives to amalgamate their unique properties into a single material. The production of these nanofibers via electrospinning is of particular interest, and whereas several studies have been done on normal nanofibers, the formation of branched nanofibers is an exciting area not currently explored. Blend solutions are formed by dissolving silk and cellulose/cellulose acetate in formic acid separately and mixing to achieve the desired ratios. …

Design Of A Custom Digital Light Projection Printer For In-Situ Production Of Composites With Improved Thermomechanical Properties, Margaret Anne Gillan

Theses and Dissertations

This work seeks to improve upon the existing state-of-the-art for vat photopolymerization additive manufacturing; namely, producing in-situ composites that combine the precision and high-performance materials of the vat photopolymerization with the strength of fiber-reinforced polymer composites. A custom-designed digital light projection printer was designed and built for printing composites, which includes an automated fiber tape system to place woven E-glass fiber mats in-situ. To validate the performance improvement of composites versus the neat matrix, composites were fabricated on the custom printer with hand-placed fiber mats. A high-performance, dual-cure resin was used for these studies. The effect of layer height on …

Development Of An Origami Inspired Composite Deployable Structure Utilizing Compliant Joints As Surrogate Folds, Samuel Porter Smith

Theses and Dissertations

This work presents the design and construction of a self-deployable, self-stiffening,and retractable (SDSR) space array from carbon fiber reinforced polymers (CFRP’s) and a working prototype is demonstrated. The effort required developing principles for the design of high-strain composite flexural joints and their integration into angled composite panels. Designing LET arrays in angled panels is explored. Analysis of simple composite LET joints is presented for two degrees of freedom. Validation of the composite LET modeling is sought through numerical methods and empirical testing. Testing of several composite LET joint specimens is conducted and the results are reported. Results indicate that (while …

Characterizing Behaviors And Functions Of Joints For Design Of Origami-Based Mechanical Systems, Nathan Chandler Brown

Theses and Dissertations

This thesis addresses a number of challenges designers face when designing deployable origami-based arrays, specifically joint selection, design, and placement within an array. In deployable systems, the selection and arrangement of joint types is key to how the system functions. The kinematics and performance of an array is directly affected by joint performance. This work develops joint metrics which are then used to compare joint performances, constructing a tool designers can use when selecting joints for an origami array. While often a single type of joint is used throughout an array, this work shows how using multiple types of joints …

Rainbow Trapping Effect In 2d Axisymmetric Broadband Acoustic Energy Harvesters, Louis Alexander Gormley

Theses and Dissertations

Acoustic energy harvesters (AEHs) collect otherwise unused ambient acoustic waves for conversion into useful electrical energy. This promising technology has potential applications ranging from grid-independent electronics to structural health monitoring systems. AEHs capture specific acoustic frequencies of interest using structures with frequency-matched component geometries. Despite the multitude of potential geometries suitable for AEH structures, existing AEH research has predominantly focused on the acoustic wave trapping performance of unidimensional or linear bidimensional AEH structures.

This study intended to broaden AEH bandwidth and capture efficiency by investigating the acoustic rainbow trapping performance of a novel 2D axisymmetric AEH design. A Finite Element …

Engineering A High-Throughput Screening Platform For Assessing Developmental Neurotoxicity Throughout Head- Regeneration In Schmidtea Mediterranea, Johnathan James Morris

Theses and Dissertations

The increase in commercially used chemicals that are inadequately evaluated for safety and risk to development has created a reticent threat to human health. Addressing these deficiencies is compounded by limited methodologies to determine the etiology of exposure-related developmental neurotoxicity (DNT). Current means of assessing DNT are largely retrospective and limited by the expensive, time-consuming, and labor-intensive use of laboratory animal models, thereby motivating a global research effort to produce alternative chemical screening assays. In this work, we have developed a novel high- throughput platform that serves as a new tool to evaluate the effects of exogenous chemical exposure on …

Acclimation Of Contact Impedance And Wrist-Based Pulsatile Signal Measurements Through Electrical Bioimpedance, Diego A. Leon

Theses and Dissertations

The purpose of this research is to expand the understanding of certain properties of electrodes used for electrical bioimpedance measurements. Specifically, this work investigates the acclimation effect of the skin-electrode interface contact impedance. It also attempts to study the relationship between electrode spacing and amplitude of bioimpedance pulsatile signals. It was found that as soon as dry electrodes are placed on the skin, the contact impedance exponentially decreases until it reaches a constant level. The acclimation time, time to reach a constant contact impedance, is dependent of the electrode size and frequency. Increasing the size of the electrode, as well …

Metodat E Llogaritjes Së Aftësisë Mbajtëse Të Themelit Për Objektin E Banimit Në Rrugën “Kemajl Hetemi”, Ferizaj, Lulzime Pira

Theses and Dissertations

Qëllimi i këtij punimi është bazuar në hulumtimet gjeologo – gjeomekanike me shpimet që janë kryer direkt në terren (in situ). Në bazë të thellësisë së shpimeve janë nxjerrë mostrat për të definuar parametrat fiziko – mekanik për llogaritjen e aftësisë mbajtëse të tokës në lokacionin e caktuar ku do të bëhet ndërtimi.

Toka është një material shumë poroz dhe heterogjen, prandaj është shumë me rëndësi përcaktimi i metodave të llogaritjes së aftësisë mbajtëse të themelit ku struktura mbështetet dhe i përcjell ngarkesat në themel varësisht prej sipërfaqes së themelit.

Në këtë punim diplome janë zbatuar dy metoda …

Characterization Of Anisotropic Materials Using Scattered Field Measurements, Hirsch M. Chizever

Theses and Dissertations

This research uses monostatic far-zone scattered field measurements to estimate the permittivity of biaxial materials at X-Band. Utilizing Radar Cross Section (RCS) measurement techniques, this effort examines the efficacy of whole-sample TEM illumination in the estimation of anisotropic permittivity, in contrast with traditional subsample illumination methods. The research examines the impact that dielectric supports have on measurement error and uncertainty in permittivity estimates. Following an incremental approach, the research first demonstrates successful estimation of permittivity for isotropic spheres followed by a Teflon isotropic cube. Finally, the method is applied to uniaxial and biaxial cubes whose anisotropic permittivity is validated through …

Applying Model-Based Systems Engineering And Fidelity Quantification To Support Fair Fight In A Distributed Simulation System, Nathaniel Erbe, David Lemmer

Theses and Dissertations

Current 5th and 6th generation fighter aircraft capabilities, and the DoD's push towards digital engineering have created an environment in which simulated testing using live, virtual, and constructive assets has increasing utility. These simulations need to be credible in the eyes of the stakeholders, which for distributed simulation systems includes establishing fair fight between simulation services. Fair fight is when multiple simulations interoperate without generating one-sided systematic advantages. Issues that impede fair fight can be categorized into interoperability issues at the simulations implementation level and incompatible representations of reality between underlying models. This research used model-based systems engineering to generate …

Requirements Analysis And Architecture For An Operational Study Of Fatigue In Usaf Mobility Aircrew, Jonathan F. Mecham

Theses and Dissertations

Aircrew fatigue in flight operations is a known hazard that has driven the creation of fatigue-reducing regulation and fatigue risk management systems industry wide. In addition, biomathematical models have been created and tested to forecast the effectiveness of aircrew under conditions of time-zone shifts and long duty days. However, limited operational studies exist to validate these models or to help understand how individual factors can affect them. Operational studies have a variety of limitations that make gathering typical data regarding fatigue or sleep difficult. This research takes systems requirement analysis approach to design a study that measures effects of circadian …

Interdependent Infrastructure Recovery Using Multilayered Networks And Optimization, Brigham A. Moore

Theses and Dissertations

Interdependent infrastructure recovery modeling and simulation are complicated due to various interdependent connections and complexities. Current efforts have identified both operational and restoration interdependency subtypes and coupling strategies that have not been integrated into one comprehensive model. This research presents a model which simultaneously integrates nine interdependency subtypes and four coupling strategies in a multi-objective format to provide the most tailorable and comprehensive network-based recovery model available. This research also created a defense-centric interdependent infrastructure database by modifying the existing CLARC database. This research then addressed assumptions regarding recovery work management in order to address the impact of work crew …

Performance Improvement Through Better Understanding Of Supply Chain Resilience, Amanda L. Femano

Theses and Dissertations

Businesses operate every day in a disruptive environment. Supply and demand uncertainty, natural disasters, global pandemics, and mishaps can all cause chaos to a supply chain’s flow. It is impossible to predict every disruption a supply chain may encounter. The best an organization can do to protect network performance is to build resilience in the supply chain and life-blood of its operations. Ensuring that a supply chain has the proper built-in mechanisms to resist and recover from disruptions is referred to as Supply Chain Resilience (SCR). While it is generally agreed that SCR can be improved through the implementation of …

Optimal Incorporation Of Non-Traditional Sensors Into The Space Domain Awareness Architecture, Albert R. Vasso

Theses and Dissertations

The United States Government is the world’s de facto provider of space object cataloging data, but is challenged to maintain pace in an increasingly complex space environment. This work advances a multi-disciplinary approach to better understand and evaluate an underexplored solution recommended by national policy, in which current collection capabilities are augmented with non-traditional sensors. System architecting and literature identify likely needs, performance measures, and contributors to a conceptualized Augmented Network. Multiple hypothetical telescope architectures are modeled and simulated on four separate days throughout the year, then evaluated against performance measures and constraints using optimization. Decision analysis and Pareto optimality …

Collaborative All-Source Navigation With Integrity, Jonathon S. Gipson

Theses and Dissertations

The novel ARMAS-SOM framework fuses collaborative all-source sensor information in a resilient manner with fault detection, exclusion, and integrity solutions recognizable to a GNSS user. This framework uses a multi-filter residual monitoring approach for fault detection and exclusion and is augmented with an additional "observability" EKF sub-layer for resilience. We monitor the a posteriori state covariances in this sub-layer to provide intrinsic awareness when navigation state observability assumptions required for integrity are in danger. This is used to selectively augment the framework with offboard information to preserve resilience. By maintaining split parallel collaborative and proprioceptive estimation instances and employing a …

Improvements To Emissive Plume And Shock Wave Diagnostics And Interpretation During Pulsed Laser Ablation Of Graphite, Timothy I. Calver

Theses and Dissertations

This dissertation covers nanosecond pulsed laser ablation of graphite for 4-5.7 J/cm² fluences with 248 nm and 532 nm lasers in 1-180 Torr helium, argon, nitrogen, air, and mixed gas. Three experiments were performed to improve the interpretation of common diagnostics used to characterize pulsed laser ablation, find simple but universal scaling relationships for comparing dynamics across different materials and ablation conditions, and provide a systematic analysis of graphite emissive plume and shock wave dynamics. A scaling of the Sedov-Taylor energy ratio was developed and validated for a range of studies despite differences in wavelength, pulse duration, fluence, and …

Application Of Vortex Tubes To Gas Turbine Film Cooling, Matthew N. Fuqua

Theses and Dissertations

To improve thermal efficiency and reduce fuel consumption, gas turbine engines typically operate at increasingly higher turbine inlet temperatures--well in excess of turbine blade material limits--and film cooling schemes are normally employed to reduce metal temperatures within acceptable limits and prevent structural failure. Cooling requirements vary across a blade surface, but there currently exists no means by which coolant temperatures can be locally adjusted to facilitate optimized usage across a blade. Ranque-Hilsch vortex tubes were investigated as a means of adjusting coolant temperatures solely by fluidic means, induced by the phenomenon of temperature separation. Analytical frameworks were developed to determine …

Pseudospectral Methods Of Robust Optimal Motion Planning For Multi-Aperture Space Systems With Motion And Vibration Compensation, Brian W. Bishop

Theses and Dissertations

For multi-body, flexible systems, the ability to achieve rapid reorientation maneuvers can be impacted by nonlinear dynamics and uncertainty in the model parameters impacting the ability to achieve an optimal trajectory computed using nominal parameter values. Trajectory sensitivity to parameter variations increases final pointing error and residual vibrational energy in the system. This manuscript explores using pseudospectral methods to generate robust optimal control trajectories minimizing trajectory sensitivity to parameter variations and derives maneuvers minimizing residual energy and pointing error. The robustness of open-loop optimal control is compared to a standard maneuver derived using traditional methods demonstrating the ability to simultaneously …

Neutron Energy Tuning Assemblies For Nuclear Weapon Environment Applications At The National Ignition Facility, Nicholas J. Quartemont

Theses and Dissertations

An energy tuning assembly was developed to spectrally shape the National Ignition Facility deuterium-tritium fusion neutron source to a notional thermonuclear and prompt fission neutron spectrum to fulfill neutron source capability gaps. The experimental neutron environment was characterized with activation dosimetry, neutronics and covariance models, and unfolded to determine the as-fielded neutron spectrum. The first energy tuning assembly was demonstrated to create synthetic spectrally accurate post-detonation fission products, enhancing U.S. technical nuclear forensics capabilities. ATHENA, a second-generation energy tuning assembly, was also optimized to meet similar objectives, but the new platform neutron fluence efficiency was increased by a factor of …

Enterprise Resource Allocation For Intruder Detection And Interception, Adam B. Haywood

Theses and Dissertations

This research considers the problem of an intruder attempting to traverse a defender's territory in which the defender locates and employs disparate sets of resources to lower the probability of a successful intrusion. The research is conducted in the form of three related research components. The first component examines the problem in which the defender subdivides their territory into spatial stages and knows the plan of intrusion. Alternative resource-probability modeling techniques as well as variable bounding techniques are examined to improve the convergence of global solvers for this nonlinear, nonconvex optimization problem. The second component studies a similar problem but …

Evaluating Testing Procedures For Openflow Controller Network Re-Provisioning Time, Steven J. Jensen

Theses and Dissertations

Software-Defined Networking promises several advantages over traditional networking architectures, but has seen little adoption. Recently codified controller evaluation methodologies have seen little validation without strong statistical analysis of the results. The research developed an environment testing implementing a published Network Re-provisioning Time methodology to evaluate five OpenFlow controllers. The methodology is strong with required parameters but had issues with some edge cases. Further refinement and adding a convergence metric may close the gaps.

Deep Learning For Weather Clustering And Forecasting, Nathaniel R. Beveridge

Theses and Dissertations

Clustering weather data is a valuable endeavor in multiple respects. The results can be used in various ways within a larger weather prediction framework or could simply serve as an analytical tool for characterizing climatic differences of a particular region of interest. This research proposes a methodology for clustering geographic locations based on the similarity in shape of their temperature time series over a long time horizon of approximately 11 months. To this end an emerging and powerful class of clustering techniques that leverages deep learning, called deep representation clustering (DRC), are utilized. Moreover, a time series specific DRC algorithm …