Mechanical Engineering Commons^™

System Architecture Optimization Using Hidden Genes Genetic Algorithms With Applications In Space Trajectory Optimization, Shadi Ahmadi Darani

Dissertations, Master's Theses and Master's Reports

In this dissertation, the concept of hidden genes genetic algorithms is developed. In system architecture optimization problems, the topology of the solution is unknown and hence, the number of design variables is variable. Hidden genes genetic algorithms are genetic algorithm based methods that are developed to handle such problems by hiding some genes in the chromosomes. The genes in the hidden genes genetic algorithms evolve through selection, mutation, and crossover operations. To determine if a gene is hidden or not, binary tags are assigned to them. The value of the tags determine the status of the genes. Different mechanisms are …

A New Technique To Determine Accommodation Coefficients Of Cryogenic Propellants, Kishan Bellur

Dissertations, Master's Theses and Master's Reports

The control of propellant boil-off is essential in long-term space missions. However, a clear understanding of cryogenic propellant phase change and the values of accommodation coefficients are lacking. To that effect, a new method to determine accommodation coefficients using a combination of neutron imaging, thin film evaporation modeling and CFD modeling has been established. Phase change experiments were conducted in the BT-2 Neutron Imaging Facility at the National Institute of Standards and Technology (NIST) by introducing cryogenic vapor (H2 and CH4) at a set pressure into Al6061 and SS316L test cells placed inside a 70mm cryostat. Condensation is achieved by …

Analysis Of The Shock Response Spectrum And Resonant Plate Testing Methods, William Larsen

Dissertations, Master's Theses and Master's Reports

Intricacies of the shock response spectrum were discovered and investigated by testing a circular plate structure with integral damping. Effects on the SRS from physical alterations to the nonlinear structure were monitored from low and high shock impulses. A method was developed and validated to estimate high amplitude shock inputs from low amplitude frequency response functions. Finite element models explored variable thickness plate designs.

Control Oriented Modeling Of An Automotive Drivetrain For Anti-Jerk Control, Gurijala Venkat Prithvi Reddy

Dissertations, Master's Theses and Master's Reports

Drivability is an important metric during the development of an automobile. Calibration engineers spend a significant amount of time trying to improve the drivability of vehicles for various driving conditions. With an increase in the available computational power in an automobile, novel model-based methods are being implemented for further improving the drivability, while reducing calibration time and effort. Phenomenon known as clunk and shuffle, which are caused due to backlash and compliance in the driveline, are a major cause of issues related to drivability and noise, vibration and harshness (NVH) during tip-in and tip-out scenarios.

This thesis focuses on developing …

Experimental And Computational Investigation Of Dual Fuel Diesel- Natural Gas Rcci Combustion In A Heavy-Duty Diesel Engine, Mufaddel Dahodwala

Dissertations, Master's Theses and Master's Reports

Among the various alternative fuels, natural gas is considered as a leading candidate for heavy-duty applications due to its availability and applicability in conventional internal combustion diesel engines. Compared to their diesel counterparts natural gas fueled spark-ignited engines have a lower power density, reduced low-end torque capability, limited altitude performance, and ammonia emissions downstream of the three-way catalyst. The dual fuel diesel/natural gas engine does not suffer with the performance limitations of the spark-ignited concept due to the flexibility of switching between different fueling modes. Considerable research has already been conducted to understand the combustion behavior of dual fuel diesel/natural …

Experimental And Modeling Study Of Particulate Matter Oxidation Under Loading Conditions For A Scr Catalyst On A Diesel Particulate Filter, Abhishek Jadav

Dissertations, Master's Theses and Master's Reports

The heavy-duty diesel engines use a Diesel Oxidation Catalyst (DOC), a Catalyzed Particulate Filter (CPF), a Selective Catalytic Reduction (SCR) with urea injection and a Ammonia Oxidation Catalyst (AMOX), to meet the US EPA 2010/2013 particulate matter (PM) and NO_x emission standards. However, it is not possible to achieve the 2015 California low NO_x standards with this arrangement. Hence, there is a need to improve the existing aftertreatment system. This can be achieved by coating the SCR catalyst on a diesel particulate filter (DPF), thus combining the PM filtration and NO_x reduction functionality into a single device. …

Physical Modeling Of Lithium-Ion Aging For Automotive Applications, Anurag Kamal

Dissertations, Master's Theses and Master's Reports

This thesis extends the full-scale electrochemical model for a Lithium-ion battery based on the porous electrode theory to incorporate aging mechanisms of solid electrolyte interface formation, cyclic electrode degradation, and lithium plating during overcharge, automotive vibrations, mechanical stress, and cell temperature, as reported in the existing literature. Further, the thesis presents the scope of the parameters used in the model to enable designers to extend the equations for new mechanisms and variability of other parameters.

An increased set of equations makes the complexity of the model even higher, and it would be very computationally complex to simulate this model. This …

Cold Start Analysis And Modeling Of A Direct-Injection Gasoline Engine, Yash Borghate

Dissertations, Master's Theses and Master's Reports

In this thesis, two different works related to cold start of a direct-injection (DI) gasoline engine are shown. First, effect of split injection is studied on engine exhaust temperature and hydrocarbon emissions for cold start conditions. Instead of single injection, two injections are done, one injection during the intake stroke and one injection during the compression stroke. Split injection is known to reduce jet wall wetting, thus reducing the hydrocarbon emissions from engine itself. Further, split injection reduces engine cycle-by-cycle variability with respect to the single injection case. Correlations between start of injection for the injection in the intake stroke …

Modeling And Analysis For Driveline Jerk Control, Prince Lakhani

Dissertations, Master's Theses and Master's Reports

In modern-day automotive industry, automotive manufacturers pay keen attention to driver’s safety and comfort by ensuring good vehicle drivability, feel of acceleration, limiting jerk and noise. The vehicle driveline plays a critical role to meet these criteria. By using high-fidelity simulation tool such as AMESim®, it is now possible to accurately model the vehicle driveline to be tested for different scenarios. With Simulink®, one can develop an efficient torque-based control system to limit the driveline oscillations and the generated noise. So, a joint simulation is used which provides a platform to evaluate the estimators and control system while considering the …

Kinesthetic Learning Experience Simulation Using An Online Intervention To Improve Hands-On Ability, David Leach

Dissertations, Master's Theses and Master's Reports

Students enrolled in mechanical and manufacturing engineering programs employ differing levels of mechanical aptitude and practical hands-on ability. Many students lack practical experience tinkering with mechanical devices and mechanisms prior to entering their post-secondary years. Student attention spans in traditional classroom environments appear to be decreasing with the ever-increasing addiction to immediate gratification provided by electronic devices, gaming software, and social media platforms. The question is then raised whether or not modern engineering students have the ability to improve mechanical aptitude by simulating a kinesthetic or tactile learning experience through an online tutorial. This project describes the development and testing …

Development Of Bosch Rate Of Injection Measurement Procedure And Results, Tyler Menucci

Dissertations, Master's Theses and Master's Reports

Recent developments in internal combustion engine technology have shown that gasoline compression ignition (GCI) combustion modes provide a viable pathway to meet future emission regulations. Lower octane middle distillate gasoline like fuels have also been formulated for GCI combustion applications and have shown similar benefits of improved fuel conversion efficiency and a reduction in particulate matter and nitrogen oxide emissions. As these gasoline like GCI fuels have not been well studied, characterization of their rate of injection (ROI) will be beneficial to supplement injector spray characterization measurements and the development of computational fluid dynamic simulations. A fuel collection method and …

Commercialization Of The Carbon Nanotube Thermophone For Active Noise Control Applications, Steven A. Senczyszyn

Dissertations, Master's Theses and Master's Reports

The rate of commercialization for technology developed in junction with academic institutions has risen dramatically over the past 30 years. Since the introduction of the Bayh-Dole Act in 1980, the amount of intellectual property owned by academic institutions has increased exponentially, and with that, there has also been an increase in the number of university spinouts generated. However, the increase of spinouts does not match the rate of increase in intellectual property. The National Science Foundation has created the Innovation Corps (I-Corps) program to help bridge this gap and provide academic professionals and students the tools necessary to commercialize technology …

An Experimental And Computational Study Of Fuel Spray Interaction: Fundamentals And Engine Applications, Le Zhao

Dissertations, Master's Theses and Master's Reports

An efficient spray injection results in better vaporization and air-fuel mixing, leading to combustion stability and reduction of emissions in the internal combustion (IC) engines. The impingement of liquid fuels on chamber wall or piston surface in IC engines is a common phenomenon and fuel film formed in the spray-piston or cylinder wall impingement plays a critical role in engine performance and emissions. Therefore, the study of the spray impingement on the chamber wall or position surface is necessary.

To understand the spray-wall interaction, a single droplet impingement on a solid surface with different conditions was first examined. The droplet-wall …

Design Optimization And High Cycle Fatigue Analysis And Of A Differential Case, Praveen Bulusu Surya Naga

Dissertations, Master's Theses and Master's Reports

Lightweight Innovations for Tomorrow (LIFT) is a consortium with several industries, universities and research institutes. It is operated by the American Lightweight Materials Manufacturing Innovation Institute (ALMMII). One of their projects, melt 5a, is to develop high silicon ductile iron (DI) alloys with improved mechanical properties and thin walled DI castings. These alloys have high strength to weight ratio compared to that of standard ductile iron (7003). Using these alloys, components can be re-designed that are much lighter which results in improved fuel efficiency, and reduced manufacturing costs and emissions. I

In this project, a differential case is being re-designed …

Spray And Combustion Studies Of High Reactivity Gasoline In Comparison To Diesel Under Advanced Compression Ignition Engine Conditions, Meng Tang

Dissertations, Master's Theses and Master's Reports

Gasoline compression ignition (GCI) technology has demonstrated great potentials in improving fuel economy and reducing engine-out NO_x and particulate matter emissions. Development and application of the GCI technology on multi-cylinder engines require both fundamental understandings of the gasoline spray combustion characteristics and accurate numerical tools. Due to the large differences in the thermo-physical and the chemical properties between gasoline and diesel range fuels, differences in the spray combustion characteristics between gasoline and diesel is expected. Reports on the gasoline spray combustion characteristics under conditions relevant to medium to heavy-duty engines are scarce and this dissertation aims to fill in …

Thermomagnetic Convective Cooling Of Hall Effect Thruster, Elizabeth M. Vanheusden

Dissertations, Master's Theses and Master's Reports

This work proposes and shows that thermomagnetic convection could be used in zero gravity to cool components of a Hall-effect thruster. A ferrofluid cavity was develop in the thermal and geometric model of a Hall-effect thruster. Simulations show that with an Ionic Liquid Ferrofluid after two minutes of thruster operations thermomagnetic convection occurs and in zero gravity will produce a larger velocity then natural convection that occurs in earth gravity. However, experiments did not result in heat transfer enhancement due to the limitation of the ferrofluid. Replacement of the Ferrotec EFH1 dispersant with dodecylbenzene did not result in Ionic Liquid …

Optimal Control Of Wave Energy Converters, Shangyan Zou

Dissertations, Master's Theses and Master's Reports

In this dissertation, we address the optimal control of the Wave Energy Converters. The Wave Energy Converters introduced in this study can be categorized as the single body heaving device, the single body pitching device, the single body three degrees of freedoms device, and the Wave Energy Converters array. Different types of Wave Energy Converters are modeled mathematically, and different optimal controls are developed for them. The objective of the optimal controllers is to maximize the energy extraction with and without the motion and control constraints. The development of the unconstrained control is first introduced which includes the implementation of …

Experimental Investigation Of Impinged Droplet Dynamics, Nitisha Ahuja

Dissertations, Master's Theses and Master's Reports

The fuel spray wall interaction phenomenon plays an essential role in determining the emissions and performance of an internal combustion engine. The investigation of single droplet wall interaction is crucial to understanding of a spray wall impingement process. This report is a compilation of the experimental work done to understand the droplet impingement characteristics, through optical diagnostics and temperature measurement. Different fuels and different surface under ambient and elevated temperature conditions are used for these tests, with two objectives: Development of a common depositionsplashing criteria; and Understanding droplet post impingement dynamics variation with factors like: Weber number (ratio of inertia …

Analysis Of Injection Parameters Influencing Gasoline Direct Injection Compression Ignition (Gdici) Engine Operation In Ltc Using Naphtha, Devyani Patil

Dissertations, Master's Theses and Master's Reports

A multi-dimensional CFD study using MTU-KIVA-Geq-CHEMKIN code has been carried out for direct injection compression ignition engine combustion fueled with heavy naphtha, light naphtha, and PRF50 in low-temperature combustion (LTC) regime. At constant fueling, combustion characteristics are investigated as a function of injection timing and injection pressure. Further, operating limits of fuel confined by combustion efficiency, noise level (Maximum Pressure rise rate) and emissions at exhaust valve opening (EVO) are evaluated using parametric variation of initial gas temperature, exhaust gas recirculation fraction, boost pressure. Research conducted focuses on ability of fuel to get good combustion which is combustion efficiency > / …

Multi-Robot Mission Planning With Energy Replenishment, Bingxi Li

Dissertations, Master's Theses and Master's Reports

Success of numerous long-term robotic explorations in air, on the ground, and under water is dependent on the ability of the robots to operate for an extended period of time. The continuous operation of robots hinges on smart energy consumption and replenishment of the robots. This dissertation addresses the multi-robot system continuous operation problem by developing two mission planning architectures regarding two types of energy replenishment, which can be adapted to different mission scenarios based on mission requirements and available resources.

The first type of energy replenishment utilizes static charging stations to provide a recharging opportunity to primary working robots, …

Optimization And Control Of An Array Of Wave Energy Converters, Jianyang Lyu

Dissertations, Master's Theses and Master's Reports

This study explored optimal configuration of both the array layout and the dimension of each WEC in the array. The array contains heaving buoys with full interaction and exact hydrodynamics. Optimization of dimension was done on each WEC in the array with a given optimal layout, and a higher q-factor was achieved. Both impedance matching optimal control and derivative control were employed, which provides both theoretical maximum energy and a more realistic case. Then the work was expanded to optimization of both the array layout and the dimension of each WEC in the array. An average of 39.21% higher q-factor …

Agile–Stage Gate Management (Asgm): Npd Implementation Practices From Global Firms Developing Complex, Physical Products, John J. Salvato

Dissertations, Master's Theses and Master's Reports

Stage Gate Management (SGM) has been used successfully by global organizations to direct the New Product Development process (NPD) for years, recently a new variant of this venerable approach has emerged. Researchers and firms have begun to intersperse elements of Agile, as popularized for the development of software, to create an Agile – Stage Gate Management (ASGM) hybrid NPD framework. Agile practitioners believe in process waste reduction, an intense focus on customers, and the creation of nimble entrepreneurial project teams, which, for software products, has positively impacted development time to market, resource utilization, and market success, more generally, improved business …

Pressure Measurements Inside Multiple Cavities Of A Torque Converter And Cfd Correlation, Edward De Jesus Rivera

Dissertations, Master's Theses and Master's Reports

A torque converter was instrumented with 29 pressure transducers. The pressure transducers were located in multiple cavities. The instrumented cavities included, four transducers mounted on the impeller shell, on the channel between blades. Six transducers mounted on the pressure and suction sides on the middle streamline of a turbine blade. Another seven transducers mounted on the pressure and suction sides of the core, middle and shell streamlines of a stator blade. Seven transducers mounted on the torque converter clutch cavity. Finally, five on the cavity between the pressure plate and the turbine shell. The torque converter was part of a …

Impact Of Pretreatment Methods On Fast Pyrolysis Of Biomass, Yash Donepudi

Dissertations, Master's Theses and Master's Reports

Biomass is considered a renewable source of energy with minimum carbon foot print if managed sustainably. The majority of the worlds energy is spend on transportation, and fast pyrolysis of biomass could be a potential route for production of a sustainable liquid transportation fuel. However, there are several hurdles in the conversion process. This work addresses these hurdles by investigating the impact of several pretreatment methods on fast pyrolysis including thermal pretreatment (torrefaction), comminution/grinding, mineral reduction. The impact of important parameters like heat transfer medium, conversion temperature and particle size were also investigated.

A mild thermal pretreatment of biomass (~10-15% …

Nanotextured Titanium Surfaces For Implants: Manufacturing And Packaging Aspects, Sachin Bhosle

Dissertations, Master's Theses and Master's Reports

It has been shown that nanotexturing the surface of otherwise smooth titanium orthopedic materials increases osteoblast proliferation in vitro, and the bone-implant contact area and pullout force in vivo. However, this prior work has not focused on the requirements for scale-up to industrial processes. This dissertation reports on titanium surface modifications by electrochemical anodization using a benign NH₄F electrolyte, and a hybrid electrolyte also containing AgF, rather than hazardous hydrofluoric acid used elsewhere. Nanotube fabrication of Ti6Al4V foils, rods, thermal plasma sprayed commercial implants, and laser and e-beam melted powder materials was demonstrated.

It was found …

Computational Studies On Biomechanics Of Concussion And On Efficacy Of Football Helmets, David Labyak

Dissertations, Master's Theses and Master's Reports

Football helmets have been used for many years to prevent head injuries to players. Over the years, the helmet design has evolved from a crude leather head covering to the more recent form fitting helmets that are seen today. The one design feature that has been common in the majority of all helmets is a hard polycarbonate shell with a foam cushion padding. The main goal of the padding layer was to reduce the amount of linear acceleration during an impact event. The one feature that has been overlooked is how stiff the padding is in rotation.

The purpose of …

Utilizing Reprap Style 3d Printers For The Manufacturing Of Composite Heat Exchangers, John Laureto

Dissertations, Master's Theses and Master's Reports

The low cost 3D printing market is currently dominated by the application of RepRap (self-replicating rapid-prototyper) variants. Presented in this document are practical utilizations of RepRap technology. Developed are innovative processes to manufacture composite materials systems for thermal management solutions.

First, a laser polymer welder system is validated by quantifying maximum peak load and weld width of linear low density polyethylene (LLDPE) lap welds as a function of linear energy density. The development of practical engineering data, in this application, is critical to producing mechanically durable welds. Developed laser and printer parameter sets allow for manufacturing of LLDPE multi-layered heat …

A Study Of High Temperature Heat Pipes And The Impact Of Magnetic Field On The Flow Of Liquid Metal, Udit Sharma

Dissertations, Master's Theses and Master's Reports

A study of high temperature heat pipe was conducted to understand its characteristics. A review of working fluid, temperature, wick structure, problems, operational limit and applications was done. Alkali metal were concluded as the most viable candidate for the working fluid.

The impact of three parameters namely magnetic field, heat flux and temperature was analyzed on the performance of HTHP (High Temperature Heat Pipe). The presence of magnetic field had the most considerable impact on reducing the pumping limit of the heat pipe while the temperature had almost negligible effect. Magnetic field results in the pressure drop and adversely affect …

Advanced Uses For Carbon Nanotubes: A Spherical Sound Source And Hot-Films As Microphones, Micaela M. Thiery

Dissertations, Master's Theses and Master's Reports

Super-aligned carbon nanotube (CNT) thin-film is used to create thermophones. The thermal properties of CNT film allow it to rapidly heat and cool when supplied AC power producing temperature and pressure gradients and, therefore, audible sound. The advantages of CNT thermophones include eliminating all moving components of traditional speakers and reducing the weight of the speaker itself by using CNT film, which is nearly weightless. Additionally, the flexibility of CNT film provides the unique opportunity to construct loudspeakers of various sizes and geometries. In this work, a spherical CNT thermophone is designed, manufactured, and tested for directivity with the overall …

Analysis Of Aeroelastic Effects On The 3-Dimensional Interference Of Wind-Turbine Rotors, Anurag Rajan

Dissertations, Master's Theses and Master's Reports

Greater penetration of wind energy demands better utilization of available wind. This has led to a formidable increase in the rotor diameter over the past few years. Bigger rotors call for lighter, more flexible blades to reduce loads and improve fatigue life. As a result, future blades will deform substantially more than the relatively stiff blades of the past. More efficient use of wind power also calls for incorporating advanced active and passive control strategies and increasing the range of velocities over which wind energy is captured. Hence an improvement in the quality of numerical simulations capable of capturing the …