Mechanical Engineering Commons^™

Fused Filament Fabrication 3d Printing Using Low-Melting Alloys., Nirupama Warrier

Electronic Theses and Dissertations

Fused Filament Fabrication (FFF) 3D printing technology has been a popular method of creating prototypes using plastics in the timeliest and most affordable manner for electronic, automotive, and biomedical applications. 3D printing of metals and alloys using FFF technology could provide low-cost alternatives and solutions to the Laser-Powder Bed Fusion Process (L-PBF) and Binder Jetting processes (BJ). In current work, low melting alloys have been used as a starting material and evaluated for FFF 3D printing using two methodologies. In the first methodology, Sn60Bi40 alloy in the form of wire was used as the feedstock for FFF extrusion and process …

Material Properties Design Using Simulations And Experiments For Powder Injection Molding Of Lead Zirconate Titanate (Pzt)., Bhushan Pramod Bandiwadekar

Electronic Theses and Dissertations

Powder injection molding (PIM) process simulations can be performed to minimize the number of injection molding experiments by estimating material properties necessary for PIM simulations. In current work, lead zirconate titanate (PZT) powder-polymer binder feedstock was compounded for 45 vol. % and 52 vol. % solids loading. PIM experiments on designed micro-pillar array geometry were performed using 52 vol. % PZT. Using PIM experiments results as basis, PIM simulations were performed on designed micro-pillar array geometries to understand the effectiveness of PIM simulations with the use of estimated feedstock properties in predicting molding behavior that have micro-features. Additionally, PIM simulations …

A Comparative Study Of Wooden And Hyrbid Composite Crossarms Of An Electric Utility Pole, Rohit Avadhani

Mechanical and Aerospace Engineering Theses - Archive

Most of the cross arms in the country are made from wood. Wood, although easily accessible, has its own defects. Environmental effects which includes the expansion and contraction of wood over the years which will disrupt its structural integrity, the presence of termites and other insects which dig into wood and destroy it from the inside, Materials wastage when it comes to improving the structural strength by increasing the cross-sectional thickness and height The replacement of wood with composites seems like a logical idea and also a solution to most of the problems. The applications of composites in our day …

Effect Of Solder Voids And Distance To Neutral Point (Dnp) On Sjr Of Wcsp Under Reflow Condition And Thermal Cycling, Aniruddha Doiphode

Mechanical and Aerospace Engineering Theses - Archive

Since the introduction of Chip Scale Packages (CSP’s) in the early 2000s, they have become one of the biggest packaging trends in recent history. There are currently over 50 different types of CSP’s available throughout the industry and the numbers are increasing almost daily. Wafer Level Chip Scale Package’s (WCSP) is kind of CSP’s used widely due to its small form factor which offers efficient use of limited space and miniaturization of the electronic device. On the other hand, small form factor typically incurs greater initial cost in product design and development. In an electronic device, it is equally important …

Strength And Damage Prognosis Of Adhesive Bond And Inter-Ply Hybrid Composites Based On Dielectric Properties, Priyanshu K. Banerjee

Mechanical and Aerospace Engineering Theses - Archive

Composite materials have found their applications in a wide range of industries particularly in the aerospace and automotive sectors. This is because they are comparatively light-weight and provide a much better corrosion and wear resistance as compared to other ceramics and metals. Adhesive bonding can be used to improve the stress distribution between these composite materials. Moreover, adhesive bond decreases the weight and concentration of stresses in the structure. Broadband Dielectric Spectroscopy, BbDS is a robust tool used for analyzing the dielectric properties of a polymer composite. This method can be used to monitor the curing process of the specimen. …

Multiphase Flow Modeling And Analysis Of Phased Filling Process For Pulsed Detonation Engine, Nirmal Kumar Umapathy

Mechanical and Aerospace Engineering Theses - Archive

Filling of reactants into a pulsed detonation engine (PDE) should be carried out quickly because any lengthening of the fill time will lead to an increased cycle time. The fill process and, the purge process constitutes a large proportion of time in a cycle. The purpose of this research was to improve the time of fill by implementing various injection geometries in two injection schemes with five different premixed stoichiometric fuel-air mixture injected at wide range of velocity. The different configurations examined were end wall injection, side wall injection with ports angled and normal to the flow direction and staggered …

An Investigation Of Topology Optimization For Coupled Thermo-Structural Loading For Additive Manufacturing, Vaibhav Shankar Gaikwad

Mechanical and Aerospace Engineering Theses - Archive

This work investigates the ability of topology optimization methods to design multifunctional components with coupled thermo-structural loading for fabrication with additive manufacturing technologies. Topology Optimization is a mathematical approach developed to perform design optimization with the purpose of reducing material usage, while maximizing the structural and thermal performance, in accordance to specific design constraints. Additive manufacturing provides the capability to create internal structures and complex surfaces developed by topology optimization that would not be possible to produce by conventional manufacturing. The more structurally efficient configuration generated by topology optimization and fabricated with additive manufacturing can result in components with improved …

Numerical Study Of Droplet Evaporation, Ritul Gandhi

Mechanical and Aerospace Engineering Theses - Archive

Droplet evaporation plays a vital role in various engineering fields such as air/fuel premixing, inkjet printing and many more. The high rate of power dissipation from the integrated circuits and chips of electronic devices creates a need for cooling it to achieve their optimal functionality. The high rate of cooling can be achieved by thin film evaporation of water by phase change as compared to the air cooling methods. Therefore, the study of droplet evaporation is necessary to understand the underlying physics and effects of different parameters on cooling performance. Numerical study of droplet evaporation has been done by using …

Computational Investigation Of The Biomechanics Of Babywearing In Regards To Developmental Dysplasia Of The Hip, Gaurav Girish

Doctoral Dissertations and Master's Theses

Developmental Dysplasia of the Hip (DDH) is a congenital condition where an infant’s hip socket is either loose or otherwise unstable. DDH causes a joint instability where the femoral head is not properly situated inside the acetabulum. Etiology of the condition is in part congenital and developmental, with a difference of DDH prevalence between ethnicities. Incidence of DDH is also in some part dependent on cultural practices and activities of the mother and child. The exact nature of this cultural incidence is not clearly understood. A computational approach is hypothesized to identify the impact of babywearing position on the healthy …

Radiative Contour Mapping Using Uas Swarm, Zachary Cook

UNLV Theses, Dissertations, Professional Papers, and Capstones

The work is related to the simulation and design of small and medium scale unmanned aerial system (UAS), and its implementation for radiation measurement and contour mapping with onboard radiation sensors. The compact high-resolution CZT sensors were integrated to UAS platforms as the plug-and-play components using Robot Operation System. The onboard data analysis provides time and position-stamped intensities of gamma-ray peaks for each sensor that are used as the input data for the swarm flight control algorithm. In this work, a UAS swarm is implemented for radiation measurement and contour mapping. The swarm of UAS has advantages over a single …

Numerical Characterization Of The Flow Field And Heat Transfer Inside The Receiver Of A Parabolic Trough Solar Collector Carrying Supercritical Co2, Samad Gharehdaghimollahajloo

UNLV Theses, Dissertations, Professional Papers, and Capstones

The aim of this research is to provide a detailed numerical analysis of flow field and heat transfer inside the heat collecting element of a parabolic trough collector. The parabolic trough collector is used as the boiler in a direct Super Critical Carbon Dioxide (S-CO2) Brayton cycle.

A single collector is modeled and analyzed with different inlet conditions. The working fluid is supercritical since its pressure is increased to above critical pressure in the compressor while its temperature reaches 300 °C after passing through the recuperators and before entering the solar field. For the first time, this research considers both …

Theoretical And Experimental Investigation On The Multiple Shape Memory Ionic Polymer-Metal Composite Actuator, Qi Shen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Development of biomimetic actuators has been an essential motivation in the study of smart materials. However, few materials are capable of controlling complex twisting and bending deformations simultaneously or separately using a dynamic control system. The ionic polymer-metal composite (IPMC) is an emerging smart material in actuation and sensing applications, such as biomimetic robotics, advanced medical devices and human affinity applications. Here, we report a Multiple Shape Memory Ionic Polymer-Metal Composite (MSM-IPMC) actuator having multiple-shape memory effect, and is able to perform complex motion by two external inputs, electrical and thermal. Prior to the development of this type of actuator, …

Museum Wave Tank Design, David James Streng, Lisa Michelle Dischinger, John Frederick Niemoller

Mechanical Engineering

The Santa Maria Discovery Museum would like to add a tsunami wave tank to be one of their demonstrations. The wave tank needs to draw the attention of their young crowd and be educationally informative about the shapes and effects of waves. As this is a museum demonstration for children, the structure, user interface, and wave making mechanism must be durable.

We are a senior project team from California Polytechnic State University that worked on this project with Allan Hancock College and Stanford University. We created waves by rapidly moving a plunger vertically in the water column. This project allows …

Thermal-Fluid Dynamic Model Of Luge Steels, Brandon Stell

Master's Theses

Luge is an Olympic sport in which athletes ride feet-first on sleds down an ice-covered track. Competitors spring from the starting position and accelerate their sled by paddling with spiked gloves against the ice surface. Once the Luger leaves the starting section, their downhill motion is solely propelled by the effects of gravity. Athletes compete, one after the other, for the fastest time. Runs can differ by as little as a thousandth of a second, meaning that every minor sled adjustment, change of line choice, and shift of body position is critical. In the past, the sport of Luge has …

Single Tower Crane Allocation Models Using Ant Colony Optimization, Carlos Abelardo Treviño

Theses and Dissertations

The construction industry greatly benefits from the utilization of heavy machines and equipment to accomplish successful projects. Tower cranes, in specific, have a crucial role in the transportation of material loads across the site. Because these machines are fixed to the ground, it is essential for planners and managers to position them in a location that provides the most efficient transfer of materials possible. This is commonly known as the tower crane allocation problem, and many researchers have attempted to optimize the tower crane location using mathematical, artificial intelligence, and simulation approaches. However, many works from the literature contain critical …

Development Of An Insulated Solar Electric Cooker (Isec) With Thermal Storage For Use In Developing World Countries, Amanda Gyokery, Spencer W. Davis, Kyle Henry Smit

Mechanical Engineering

According to the World Health Organization, about half of the world’s population uses biomass stoves to cook their meals. However, biomass fires can be dangerous. Unattended biomass fires and indoor air pollution are responsible for an estimated 600,000 deaths annually and the creation of approximately 4 million instances of chronic disease. They also release CO2 and other pollutants into the air, and require the families to gather enough material to keep it burning (WHO 2017). Although cleaner cooking technology seems like a clear solution, often families are either unwilling to change how they cook food or are unable to afford …

Design And Analysis Of Compressed Air Power Harvesting Systems, Zachary James Sadler

Theses and Dissertations

Procedure for site discovery, system design, and optimization of power harvesting systems is developed with an emphasis on application to air compressors. Limitations for the usage of infrared pyrometers is evaluated. A system of governing equations for thermoelectric generators is developed. A solution method for solving the system of equations is created in order to predict power output from the device. Payback analysis is proposed for determining economic viability. A genetic algorithm is used to optimize the power harvesting system payback with changing quantities and varieties of thermoelectric generators, as well as the back work put into cooling the thermoelectric …

The Effects Of Exhaust Vent Location On Thermal Comfort Inside The Residential Buildings Equipped With An Evaporative Cooling System, Armin Saraei

UNLV Theses, Dissertations, Professional Papers, and Capstones

Inlet and outlet conditions, Including size and location, have significant effects on the air distribution, temperature, humidity and thermal comfort in the buildings. In the current study, various strategies are presented for exhaust air vents and the effects of inlet and outlet vents locations are evaluated on providing thermal comfort in the residential and industrial buildings. To provide thermal comfort, three key factors need to be investigated based on ASHRAE standard 55- 2013 as follows: Comfort Zone, Thermal Sensation and Draft Rate. Flow distribution is studied as well in order to investigate the strategies, which make more vorticity in the …

Investigating The Influence Of Functional And Nonfunctional Requirements On Change And Change Propagation, Nathaniel Conde Voris

Theses and Dissertations

The research presented in this thesis investigates the nature of change and change propagation in requirement documents as they are influenced by requirement type, that is, “Functional” or “NonFunctional,” and how an understanding of these types may refine utilization of the Automated Requirement Change Propagation Prediction (ARCPP) tool when used by design teams. Functionality is determined by asking the question “Does the requirement prescribe something for the project to accomplish?” This question separates the requirements into their requisite types. Using the ARCPP, the relationship and propagation scores were determined for each requirement. Furthermore, the number of relationships were determined for …

Design Of Metal Oxides/Metal Sulfides For The Improvement Of Sodium Ion Batteries, David E. Flores

Theses and Dissertations

Herein, the improvement in performance for sodium ion batteries (NIBs) is discussed from available literature and work conducted in the laboratory setting to demonstrate the ability of sodium to perform in the world of energy storage. The reason that sodium is being explored as an alternative to Lithium in energy storage devices is because of the potential depletion of the lithium in the world causing lithium prices to surge. Researchers show that many Sn, Sb, Ge, and other composites perform well as anode materials within NIBs. The research conducted in the dissertation applies the Forcespinning method to produce fibers for …

Study Of Latent Heat Thermal Energy Storage Systems For Concentrated Solar Power Plants, Hermes Chirino

Theses and Dissertations

Concentrated Solar Power (CSP) using phase change material (PCM) as the storage medium in the Thermal Energy Storage (TES) system is a promising technology for large scale utilization of solar thermal energy because heat latent heat thermal energy storage (LHTES) systems can store more energy as the latent heat during the melting process.

This study analyzes the different dimensionless parameters from the 1-D transient enthalpy-based mathematical model used to simulate the heat transfer and flow within the LHTES system. These dimensionless parameters are varied and analyzed with the main objective of increasing thermal energy storage efficiency and exergy efficiency of …

Effect Of Processing Parameters On The Electrochemical Performance Of Forcespun Metal Oxide/Carbon Composite Fibers For Li-Ion Batteries, Howard A. Campos

Theses and Dissertations

Metal oxides have been gaining interest as electrode materials for rechargeable Li-ion batteries due to various properties including low cost, low toxicity, and high theoretical capacity. In this research work the effect of two different metal oxide/carbon fiber composites, Fe3O4/C and ZnO/C, on the electrochemical performance for Li-ion batteries will be explored. This is also the first time that results are reported, to the best of our knowledge, of these fiber composites through the Forcespinning ® method. Scanning electron microscopy (SEM), Energy-Dispersive X-ray Analysis (EDS), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and electrochemical analysis were used to investigate …

A Globally Stable Attractor That Is Locally Unstable Everywhere, Phanindra Tallapragada, Senbagaraman Sudarsanam

Publications

We construct two examples of invariant manifolds that despite being locally unstable at every point in the transverse direction are globally stable. Using numerical simulations we show that these invariant manifolds temporarily repel nearby trajectories but act as global attractors. We formulate an explanation for such global stability in terms of the ‘rate of rotation’ of the stable and unstable eigenvectors spanning the normal subspace associated with each point of the invariant manifold. We discuss the role of this rate of rotation on the transitions between the stable and unstable regimes.

Development Of A Multiphase Photon Monte Carlo Method For Spray Combustion And Its Application In High-Pressure Conditions, Somesh Roy, Jian Cai, Michael F. Modest

Mechanical Engineering Faculty Research and Publications

In this work the development of a multiphase photon Monte Carlo (PMC) method with a focus on resolving radiative heat transfer in combustion simulations is presented. The multiphase PMC solver can account for description of participating media in both Lagrangian and Eulerian frameworks. The solver is validated against exact solutions in several one-dimensional configurations. The developed solver is then applied to Diesel spray combustions, where liquid spray droplets are assumed to be cold, nonemitting, large, and isotropically scattering. Several formulations for radiative properties of the Diesel spray are first explored. The PMC solver has then been coupled with the multiphase …

Towards Green Building: Energy Efficient Roof System For Buildings, Dhruv Sangal

Theses and Dissertations

The present work focusses on investigating the thermal performance of different energy efficient roof systems for buildings for different climates. Buildings constitutes about 40 percent of total energy consumed by United States, and previous research shows that 20 percent of the building cooling load comes through ceiling of a building. Thus, it is important to analyze different energy efficient roof systems which can help in reducing building cooling and heating load. The present study focusses on three technologies – green roof, radiant barriers and photovoltaics. To analyze the performance of these systems, a detailed energy based mathematical model were developed …

Temporal Transformation Of Barrier Islands A Round Nakdong Estuary, Sukzun Youn

Theses and Dissertations

The Nakdong Estuary system near Busan, South Korea consists of dynamic shorelines characterized by morphological transformations that result from both natural disasters (typhoons and flooding) and construction projects (Nakdong Estuary Dam, gates in the West Nakdong River and Busan New-ports). This study aims to synthesize existing data for tides, waves, bathymetry and meteorological data obtained from a variety of institutions with the objectives of (1) identifying and ranking major factors that influence morphological transformations and (2) determining how these factors influence morphological change over time. These objectives were met by analyzing patterns of flow and sediment transport using Center Point …

Deep Well Pump Seal, Peter M. Gordon, Matt C. Johnson, Dylan A. Smith

Mechanical Engineering

Lifewater International, a Christian non-profit, trains locals to repair water well hand pumps in various third world countries. It would be beneficial to retrofit difficult-to-repair hand pumps with a locally-made pump cylinder such as HydroMission's "SlapShot". The majority of the components in the "SlapShot" can be easily obtained in rural third world villages. However, the thick leather gaskets required to seal the water cylinder during the pumping operation are imported. These thick leather gaskets are expensive, and when they fail, this results in pumps being out of commission for extended periods of time. Lifewater has presented this problem to a …

Dyno-Mite Redesign, Brandon Joseph Miller, Daniel Robert Hoffman, Richard Demedici Young

Mechanical Engineering

The Cal Poly Mechanical Control Systems Laboratory currently employs an outdated device, known as the Motomatic, to teach students about various motor characteristics and control methods. These include open-loop vs. closed-loop control, speed vs. position control, and DC motor response curves. The current device does not function properly and produces unreliable data due to overwhelming non-linear effects such as stiction and shaft misalignment. Our team was tasked with designing a replacement device that retains many of the same educational goals as the original lab procedure, while also adding new educational goals pertaining to the device system dynamics. The new apparatus, …

Rogue Rotary - Modular Robotic Rotary Joint Design, Sean Wesley Murphy, Tyler David Riessen, Jacob Mark Triplett

Mechanical Engineering

This paper describes the design process from ideation to test validation for a singular robotic joint to be configured into a myriad of system level of robots.

Poly Spotlight Control, Ryan P. O'Neill, C. Oleg Frandle, Anthony T. Lombardi

Mechanical Engineering

When this project began, The Cambria Center for the Arts Theater used a manually-operated spotlight. The sound created by the fans, along with the sheer size of the spotlight, required that it be housed in an attic room above the theater and shined through a closed window. This trapped a lot of heat in the room and involved some risk with climbing into and out of the attic room. This project sought to remedy those issues by mounting a pair of newer LED spotlights inside the theater. Doing this required a method for remotely controlling and actuating the angular position …