Engineering Commons^™

One Dimensional Computer Modeling Of A Lithium-Ion Battery, Ashwin S. Borakhadikar

Browse all Theses and Dissertations

Renewable energy storage is vitally important to many applications for which batteries are the finest choice. As energy storage technology may be applied to a number of areas that differ in power and energy requirements, modeling of battery performance is required. In recent years, a lot of research has been done in this area but, the earliest model was designed by Marc Doyle, T. F. Fuller, and J. Newman in 1993. This work involves the development of a one-dimensional computer model of a lithium-ion battery which consists of three domains: the negative electrode, the separator, and the positive electrode. The …

A Numerical And Experimental Investigation Of Steady-State And Transient Melt Pool Dimensions In Additive Manufacturing Of Invar 36, Chigozie Nwachukwu Obidigbo

Browse all Theses and Dissertations

The use of additive manufacturing (AM) in tooling enables low production components to be fabricated with lower costs, reduced waste, increased design flexibility and reduced lead time. Invar 36 is a popular metal tooling material known for its low coefficient of thermal expansion. This work uses thermal finite element (FE) modeling as a tool to determine the feasibility of using Invar 36 in AM and to investigate the transient effect from common scanning strategies. Results show that the steady-state melt pool dimensions behave similar to traditional AM materials for varying process parameters. Transient results show that the melt pool response …

Modeling Two Phase Flow Heat Exchangers For Next Generation Aircraft, Hayder Hasan Jaafar Al-Sarraf

Browse all Theses and Dissertations

Two-phase heat exchangers offer the potential of significant energy transfer by taking advantage of the latent heat of vaporization as the working fluid changes phase. Unfortunately, the flow physics of the phase change process is very complex and there are significant gaps in the fundamental knowledge of how several key parameters are affected by the phase change process. Therefore, an initial investigation modeling a two-phase flow heat exchanger has been accomplished. Many key assumptions have been defined which are critical to modeling two-phase flows. This research lays an initial foundation on which further investigations can build upon. Two-phase heat exchangers …

Anisotropy Evolution Due To Surface Treatment On 3d-Printed Fused Deposition Modeling (Fdm) Of Acrylonitrile Butadiene Styrene (Abs), Blake E. Lozinski

Honors Undergraduate Theses

Purpose: This paper will present insight to the methodology and results of the experimental characterization of Acrylonitrile Butadiene Styrene (ABS) using Fused Deposition Modeling (FDM). The work in this research explored the effects of print orientation, surface treatment, and ultraviolet (UV) light degradation with the utilization of Digital Image Correlation (DIC) on ABS tensile specimens.

Design/methodology: ABS specimens were printed at three build orientations (flat (0 degrees), 45 degrees, and up-right (90 degrees)). Each of these specimens were treated with three different surface treatments including a control (acrylic paint, Cyanoacrylate, and Diglycidyl Bisphenol A) followed by exposure to UV light …

Multi-Axial Thermomechanical Characterization Of Shape Memory Alloys For Improved Stability, Douglas Nicholson

Electronic Theses and Dissertations

Shape recovery in shape memory alloys (SMAs) occurs against external stress by means of a reversible thermoelastic solid state phase transformation typically between so-called austenite, martensite and R-phases. The ability to do work enables their use as high-force actuators in automotive and aerospace applications while superelastic NiTi is of interest in biomedical devices such as stents. Both R-phase and martensite can detwin, reorient and undergo a thermal or stress induced transformation. For these reasons, it is difficult from ordinary macroscopic measurements to decouple elastic and inelastic contributions (from their respective phases) from the overall deformation. In situ neutron diffraction is …

Development Of High Efficiency Dry Powder Inhalers For Use With Spray Dried Formulations, Dale Farkas

Theses and Dissertations

Dry powder inhalers (DPIs) are advantageous for delivering medication to the lungs for the treatment of respiratory diseases because of the stability of the powders, relative low cost, synchronization of inhalation and dose delivery, and many design options that can be used for optimization. However, currently marketed DPIs are very inefficient in delivering medications to the lungs. This study has developed multiple new high efficiency DPIs for use with spray dried excipient enhanced growth (EEG) powder formulations based on the following platforms: capsule-based for oral inhalation, high-dose for oral inhalation, inline with 3D rod array dispersion, and inline with capillary …

Development Of An Excel® Rocket Simulator For Application In Middle School, High-School, And University Stem Education, Melvin Lee Hortman

All Master's Theses

Water rocket activities are one of the most popular STEM activities used in primary, secondary, and higher education yet are void of engineering, though engineering is heavily implied in the STEM acronym. This study investigated the amount of engineering present in water rocket activities, and options for emphasizing engineering more in water rocket activities using an open-platform flight simulator for use by educators to enable students to predict flight parameters of a water rocket they designed, and test those predictions against experimental data. The simulator was constructed in Excel® with many functions, but the function validated in this study was …

Investigation Of The Use Of 3-D Printer Platform As Building Block For Rapid Design Of Research And Manufacturing Tool, Handy Chandra

Dissertations, Master's Theses and Master's Reports

This thesis attempts to show how an open source 3-D printer platform, the self replicating rapid prototype (RepRap), could be used to accelerate the development of research and manufacturing tools. Two projects are shown as examples, both utilizing components of the 3-D printer platform.

The first project is to develop an instrument capable of performing automated large-area four-point probe measurements. A modified RepRap 3-D Printer with a four-point probe in place of the 3-D printer head is utilized as a precision positioning platform. The printer together with custom designed measurement circuit and software performs automated measurement on multiple points on …

A Computational Study Of The Kinematics Of Femoroacetabular Morphology During A Sit-To-Stand Transfer, Brandon K. Marine

Theses and Dissertations

Computational modeling in the field of biomechanics is becoming increasingly popular and successful in practice for its ability to predict function and provide information that would otherwise be unobtainable. Through the application of these new and constantly improving methods, kinematics and joint contact characteristics in pathological conditions of femoroacetabular impingement (FAI) and total hip arthroplasty (THA) were studied using a lower extremity computational model. Patients presenting with FAI exhibit abnormal contact between the femoral neck and acetabular rim leading to surrounding tissue damage in daily use. THA is the replacement of both the proximal femur and acetabular region of the …

Eliminating The Illusion Of Learning From Engineering Courses, Jason Weaver

Faculty Publications

This paper describes the efforts of the author to incorporate tools into an undergraduate engineering course to help facilitate better learning and assess proficiency more effectively by avoiding the illusion of learning. Several techniques are used, including suggestions from the recent book Make It Stick by Brown, Roediger, and McDaniel. Student feedback and instructor observations are discussed, and future recommendations for the course are given

Adaptive Scheduling For Operating Room Management, Honghan Ye

Theses and Dissertations--Mechanical Engineering

The perioperative process in hospitals can be modelled as a 3-stage no-wait flow shop. The utilization of OR units and the average waiting time of patients are related to makespan and total completion time, respectively. However, minimizations of makespan and total completion time are NP-hard and NP-complete. Consequently, achieving good effectiveness and efficiency is a challenge in no-wait flow shop scheduling. The average idle time (AIT) and current and future idle time (CFI) heuristics are proposed to minimize makespan and total completion time, respectively. To improve effectiveness, current idle times and future idle times are taken into consideration …

The Limits & Effects Of Draw On Properties And Morphology Of Pan-Based Precursor And The Resultant Carbon Fibers, Sarah Edrington

Theses and Dissertations--Mechanical Engineering

The process, structure, and property relationship of PAN fiber as a precursor to carbon fiber was studied. The limitations of stable spinning and property improvement associated with hot draw in solution spinning were found and quantified. Conditions were varied to generated precursor fiber up to the limit of draw, from which actual samples were collected for thermal conversion to carbon fiber. Samples of PAN and subsequent carbon fiber were characterized using tensile testing and x-ray analysis. The effects of draw on modulus and break stress, as well as the orientation of the crystalline structure of both parent precursor and resultant …

Shape Memory Behavior Of Dense And Porous Niti Alloys Fabricated By Selective Laser Melting, Soheil Saedi

Theses and Dissertations--Mechanical Engineering

Selective Laser Melting (SLM) of Additive Manufacturing is an attractive fabrication method that employs CAD data to selectively melt the metal powder layer by layer via a laser beam and produce a 3D part. This method not only opens a new window in overcoming traditional NiTi fabrication problems but also for producing porous or complex shaped structures. The combination of SLM fabrication advantages with the unique properties of NiTi alloys, such as shape memory effect, superelasticity, high ductility, work output, corrosion, biocompatibility, etc. makes SLM NiTi alloys extremely promising for numerous applications.

The SLM process parameters such as laser power, …

Computational Investigation Of Transmural Differences In Left Ventricular Contractility And Hydrogel Injection Treatment For Myocardial Infarction, Hua Wang

Theses and Dissertations--Mechanical Engineering

Heart failure (HF) is one of the leading causes of death and impacts millions of people throughout the world. Recently, injectable hydrogels have been developed as a potential new therapy to treat myocardium infarction (MI). This dissertation is focused on two main topics: 1) to gain a better understanding the transmural contractility in the healthy left ventricle (LV) wall and 2) investigate the efficacy of the hydrogel injection treatment on LV wall stress and function. The results indicate that a non-uniform distribution of myocardial contractility in the LV wall provide a better representation of normal LV function. The other important …

Data-Driven Adaptive Reynolds-Averaged Navier-Stokes K - Ω Models For Turbulent Flow-Field Simulations, Zhiyong Li

Theses and Dissertations--Mechanical Engineering

The data-driven adaptive algorithms are explored as a means of increasing the accuracy of Reynolds-averaged turbulence models. This dissertation presents two new data-driven adaptive computational models for simulating turbulent flow, where partial-but-incomplete measurement data is available. These models automatically adjust (i.e., adapts) the closure coefficients of the Reynolds-averaged Navier-Stokes (RANS) k-ω turbulence equations to improve agreement between the simulated flow and a set of prescribed measurement data.

The first approach is the data-driven adaptive RANS k-ω (D-DARK) model. It is validated with three canonical flow geometries: pipe flow, the backward-facing step, and flow around an airfoil. For all 3 test …

Effects Of Temperature, Orientation, Load Level And Indenter Shape On The Indentation Response Of Niti-Based Shape Memory Alloys, Peizhen Li

Theses and Dissertations--Mechanical Engineering

Owing the capability of recovering large deformations through reversible phase transformation, shape memory alloys (SMAs) are well-known for their unique behaviors such as shape memory effect (SME) and superelasticity (SE), which can also be characterized by instrumented indentation techniques. Nickel titanium (NiTi) SMAs have been extensively used for nano/micro-indentation studies and widely applied to biomedical and other elaborate medical devices.

In this study, indentation responses of NiTi, NiTiHf, NiTiHfPd and NiTiHfCu alloys were investigated using spherical and Berkovich indenters at room temperature. Spherical and Berkovich indentation hardness, modulus, and work/depth recoverable ratio of these NiTi-based alloys were revealed as a …

Analytical And Boundary Element Solutions Of Bulk Reacting Lined Ducts And Parallel-Baffle Silencers, Jundong Li

Theses and Dissertations--Mechanical Engineering

Lined silencers of various configurations are used to attenuate the noise from building HVAC equipment, gas turbines, and other machinery. First-mode analytical solutions are presented for sound attenuation along rectangular lined ducts, parallel-baffle silencers, and circular lined ducts. The sound absorptive lining is treated using a bulk property model. The analytical solutions entail solving a nonlinear characteristic equation in the transverse direction after the rigid-wall boundary condition is applied. The solution is compared to the boundary element solution and a local impedance analytical solution for several test cases.

A Framework And Metrics For Sustainable Manufacturing Performance Evaluation At The Production Line, Plant And Enterprise Levels, Aihua Huang

Theses and Dissertations--Mechanical Engineering

Sustainable manufacturing is becoming increasingly important due to scarcity of natural resources, stricter regulations and increasing customer demand for sustainable products. Sustainable manufacturing involves the use of sustainable processes and systems to produce more sustainable products. In order to meet these demands for sustainable products, manufacturing companies have to adopt numerous strategies to achieve sustainable manufacturing. The approach for evaluating sustainable products and processes have been investigated in previous work where product/process sustainability indices were proposed. However, no comprehensive methods are available for sustainable manufacturing performance evaluation at the system level. This work aims to develop two alternate methods for …

Advances In Multi-Agent Flocking: Continuous-Time And Discrete-Time Algorithms, Brandon Wellman

Theses and Dissertations--Mechanical Engineering

We present multi-agent control methods that address flocking in continuous-time and discrete-time settings. The method is decentralized, that is, each agents controller relies on local sensing to determine the relative positions and velocities of nearby agents. In the continuous-time setting, each agent has double-integrator dynamics. In the discrete-time setting, each agent has the discrete-time double-integrator dynamics obtained by sampling the continuous-time double integrator and applying a zero-order hold on the control input. We demonstrate using analysis, numerical simulations, and experimental demonstrations that agents using the flocking methods converge to flocking formations and follow the centralized leader (if applicable).

Development Of A Supplier Segmentation Method For Increased Resilience And Robustness: A Study Using Agent Based Modeling And Simulation, Adam J. Brown

Theses and Dissertations--Mechanical Engineering

Supply chain management is a complex process requiring the coordination of numerous decisions in the attempt to balance often-conflicting objectives such as quality, cost, and on-time delivery. To meet these and other objectives, a focal company must develop organized systems for establishing and managing its supplier relationships. A reliable, decision-support tool is needed for selecting the best procurement strategy for each supplier, given knowledge of the existing sourcing environment. Supplier segmentation is a well-established and resource-efficient tool used to identify procurement strategies for groups of suppliers with similar characteristics. However, the existing methods of segmentation generally select strategies that optimize …

Utilization Of Empirical Models To Determine The Bulk Properties Of Compressed Sound Absorptive Materials, Ruimeng Wu

Theses and Dissertations--Mechanical Engineering

Empirical models based on flow resistivity are commonly used to determine the bulk properties of porous sound absorbing materials. The bulk properties include the complex wavenumber and complex characteristic impedance which can be used directly in simulation models. Moreover, the bulk properties can also be utilized to determine the normal incidence sound absorption and specific acoustic impedance for sound absorbing materials of any thickness and for design of layered materials. The sound absorption coefficient of sound absorbing materials is measured in an impedance tube using wave decomposition and the measured data is used to determine the flow resistivity of the …

Autonomous Quadrotor Collision Avoidance And Destination Seeking In A Gps-Denied Environment, Thomas C. Kirven

Theses and Dissertations--Mechanical Engineering

This thesis presents a real-time autonomous guidance and control method for a quadrotor in a GPS-denied environment. The quadrotor autonomously seeks a destination while it avoids obstacles whose shape and position are initially unknown. We implement the obstacle avoidance and destination seeking methods using off-the-shelf sensors, including a vision-sensing camera. The vision-sensing camera detects the positions of points on the surface of obstacles. We use this obstacle position data and a potential-field method to generate velocity commands. We present a backstepping controller that uses the velocity commands to generate the quadrotor's control inputs. In indoor experiments, we demonstrate that the …

High Sensitivity Refractometer Based On Reflective Smf-Small Diameter No Core Fiber Structure, Guorui Zhou, Qiang Qu, Rahul Kumar, Wai Pang Ng, Hao Liu, Longfei Niu, Nageswara Lalam, Xiaodong Yuan, Yuliya Semenova

Conference Papers

A high sensitivity refractive index sensor based on a single mode-small diameter no core fiber structure is proposed. In this structure, a small diameter no core fiber (SDNCF) used as a sensor probe, was fusion spliced to the end face of a traditional single mode fiber (SMF) and the end face of the SDNCF was coated with a thin film of gold to provide reflective light. The influence of SDNCF diameter and length on the refractive index sensitivity of the sensor has been investigated by both simulations and experiments, where results show that the diameter of SDNCF has significant influence. …

Variable Oxidation & Defects In Ti-6al-4v Material In Electron Beam Melting Additive Manufacturing, Edward Patton Clark

Electronic Theses and Dissertations

Powder-based metal in additive manufacturing (AM) is advantageous for rapid prototyping of parts and components, with the benefit of reusing powder to reduce production costs. A common driver in the aerospace industry is free-form complex geometries which can be created using CAD software to optimize specifications with strength-to-weight ratios in components. Weight optimization of aircraft components using additive manufacturing reduces material, which significantly reduces production cost in comparison to cast and wrought metallic products. Large biomedical and aerospace industries heavily invest in feedstock metal powders that have low density under structural stresses and high temperatures, resulting in superior resistance to …

Effect Of Vibration Of Unconsolidated Sand On The Performance Of Interferometric Vibration Sensors, Cody Berrey

Electronic Theses and Dissertations

Interferometric vibration sensors are widely used for ground vibration measurements where traditional contact sensors are not desired. Laser Doppler vibrometers (LDV) and digital speckle pattern interferometers are studied in this thesis. The working principle of laser Doppler vibrometry and digital shearography is described. The effect of vibration of the unconsolidated sand on the performance of both sensors is experimentally investigated.

The vibration of unconsolidated sand can cause an increase of noise in the laser Doppler vibrometer output and cause speckle decorrelation in digital speckle pattern interferometry (referred to as digital shearography). An experimental investigation of the effect of varying the …

Advancing Intersection Management By Utilizing Cost Effective Intelligent Vehicle Concepts And Vehicle-To-Infrastructure Communication Techniques, Bernard O. Ibru

Electronic Theses and Dissertations

Intelligent Transport Systems (ITS) is a growing field of research which focuses on the alleviation of traffic congestion and road accidents caused by miscommunication or confusion of human drivers. Intelligent Intersection Management is a subdivision of ITS which focuses on the seamless management of vehicles arriving at, traversing and exiting intersections to prevent congestion and collision within or around the intersection. This research sought to develop a cost effective method of implementing wireless Vehicle-to-Infrastructure (V2I) communication based Intelligent Intersection Management, by employing the use of 1:4.5 scale version autonomous vehicle prototypes, on a similarly scaled four-way intersection. This was accomplished …

Audio-Based Productivity Forecasting Of Construction Cyclic Activities, Chris A. Sabillon

Electronic Theses and Dissertations

Due to its high cost, project managers must be able to monitor the performance of construction heavy equipment promptly. This cannot be achieved through traditional management techniques, which are based on direct observation or on estimations from historical data. Some manufacturers have started to integrate their proprietary technologies, but construction contractors are unlikely to have a fleet of entirely new and single manufacturer equipment for this to represent a solution. Third party automated approaches include the use of active sensors such as accelerometers and gyroscopes, passive technologies such as computer vision and image processing, and audio signal processing. Hitherto, most …

Precise Flow-Control Using Photo-Actuated Hydrogel Valves And Pid-Controlled Led Actuation, Colm Delaney, Simon Coleman, Jeff Whyte, Nigel Kent, Dermot Diamond

Articles

Herein we demonstrate remarkable control of flow within fluidic channels using photo-actuated hydrogel valves. By polymerizing the valves in situ it has been possible to create highly reproducible valves. Through the use of an LED platform and a PID algorithm we have generated extremely accurate flow control and created prototype devices to document their potential application within the microfluidics field.

The Evaluation And Implementation Of Magnetic Fields Suitable For Biaxial Cyclic Testing Of Magnetorheological Elastomers, Dave Gorman

Doctoral

This thesis addresses the current lack of specification of magnetic fields currently used in the physical testing of Magnetorheological Elastomers MREs as well as providing the first comparative test results for MREs subject to both biaxial and uniaxial cyclic loading in the same magnetic field. In order to design an electromagnetic array capable of generating a suitable magnetic field for the cyclic biaxial testing of MREs, a review of currently used magnetic fields for uniaxial testing of MREs was carried out and a suitable array was modelled and evaluated with both 2D and 3D FEA software. Once the FEA analysis …

Precision Control Of Flow Rate In Microfluidic Channels Using Photoresponsive Soft Polymer Actuators, Colm Delaney, Peter Mccluskey, Simon Coleman, Jeffrey Whyte, Nigel Kent, Dermot Diamond

Articles

A novel approach that allows control of flow in microfluidic channels with unsurpassed performance using light is described. Valve structures have been created using photoresponsive hydrogels based on spiropyran-functionalised pNIPAAm hydrogels photopolymerised around pillar structures within the channels. Valve actuation is controlled from outside the fluidic system using externally located LEDs. Highly precise and accurate flow rates can be selected by passing real-time flow rate measurements into a PID algorithm. The optimised algorithm also minimises overshoot of the selected flow rate, eliminates flow rate drift, and improves the system response time. In addition to the dramatic improvements in flow rate …