Mechanical Engineering Commons^™

Mechanical Reinforcement Of Polyacrylamide Hydrogels Using Pristine Single-Walled Carbon Nanotubes, Wuxiang Feng

Graduate Dissertations and Theses

Hydrogels have great promise as an innovative biomedical material possessing many advantages such as high water content, porous structure, and excellent biocompatibility. Although hydrogels have been used to develop some successful applications, they commonly do not have sufficient mechanical strength required for artificial soft tissues. Here, the author fabricated reinforced PAAm hydrogels using single-walled carbon nanotubes as reinforcing materials. The fusion of SWCNTs and the PAAm matrix successfully generated SWCNTs/PAAm hybrid gels with improved mechanical strength. Moreover, the aqueous dispersion of SWCNTs used for engineering the hybrid gels remained excellent stability after two months. SEM images from previous research and …

Gait Modeling Using Genetic Algorithm Optimized Four-Bar Linkages, Hazen James Hamather

Graduate Theses - Mechanical Engineering

Important in diagnosing gait abnormalities and pathologies is knowing the position of the leg at various points throughout the gait cycle. This is currently done with motion capture technology but the demand for Inertial Measurement Unit (IMU) based navigation and position tracking has been on the rise. A required component of this alternative is a gait model that can accurately predict the position of points of interest. In this thesis, a Kalman Filter is constructed using a contrived model to test if, given an accurate gait model, the filter can converge to an accurate and true position solution. Also presented …

A Human Powered Micro-Generator For Charging Electronic Devices, John Adam

Senior Theses

A hand-pulled generator has been designed and tested. A preliminary result has been obtained and discussed. This device was created to provide outlet-free charging. Electronic devices are useful when going out into the wilderness. A portable power supply is necessary to keep an electronic device alive. This project created a device that converts human energy into electricity to charge electronic devices. This thesis overviews the device’s design, build, and tests. Two different tests were run to determine that the device is capable of charging the storage battery. The device presented can provide 14 minutes of charging time with one hour …

Effects Of Tension On Resonant Frequencies Of Strings, Blake Burnett

Senior Theses

This project tests and explores resonance of strings. Since all materials and mechanisms are affected by vibrations, it is important to know the frequencies at which resonance occurs. To explore this subject, strings were used as a model material to test the effect tension has on resonance. The fundamental frequencies and the corresponding modes of resonance were used to analyze the data. The results of this experiment show that increasing tension on a string increases its resonance frequency. Understanding the physics behind resonance frequency allows systems to be designed to take advantage of resonance properties, or to avoid resonance where …

Measuring The Double Layer Capacitance Of Electrolyte Solutions Using A Graphene Field Effect Transistor, Agatha Ulibarri

Senior Theses

When operating graphene field effect transistors (GFETs) in fluid, a double layer capacitance (C_dl) is formed at the surface. In the literature, the C_dl is estimated using values obtained using metal electrode experiments. Due to the distinctive electronic and surface properties of graphene, there is reason to believe these estimates are inadequate. This work seeks to directly characterize the double layer capacitance of a GFET. A unique method for determining the C_dl has been implemented, and data has been obtained for three electrolytes and one ionic fluid. The results yield dramatically lower C_dl values than …

The Effects Of Surface Pace In Baseball, Jason Farlow

Senior Theses

A baseball travels across different surfaces at different paces. The goal of this experiment is to find a percentage difference in speeds the ball will reflect off a given surface. The energy lost on the turf surface was far more significant than on dirt surface as the turf lost an average of 26% of its energy as compared to just 16% of the energy on dirt. In the Northwest conference, teams play on four turf-based infields and five dirt-based infields. The results of this study suggest that kinetic friction forces are more significant in reducing ball rebound speed than in …

A Numerical Investigation Of Bio-Inspired Scaffolds And Surface Textures, Yucong Gu

Graduate Theses and Dissertations

Synthetic scaffolds are widely used as implants to repair bone fracture. Without a proper design, scaffolds could pose significant health risks to the patient and fail to heal the bone properly. A good synthetic scaffold needs to have high porosity and large pore size to allow new bone cells to form on it. However, a scaffold with higher porosity and larger pore size tends to have reduced mechanical strength. Thus, it is important to find a structural design which allows the implant to have a high porosity and large pore size while retaining high strength. In this research, a 3D-printable …

Microheater Array Powder Sintering (Maps) For Printing Flexible Electronics, Nicholas Holt

Graduate Theses and Dissertations

Microheater array powder sintering (MAPS) is a novel additive manufacturing process that uses an array of microheaters to selectively sinter powder particles. MAPS shows great promise as a new method of printing flexible electronics by enabling digital curing of conductive inks on a variety of substrates. MAPS operation relies on establishing a precision air gap of a few microns between an array of microheaters, which can reach temperatures of 600°C, and a layer of conductive ink which can be deposited onto a flexible substrate. This system presents challenges, being: the fabrication of a microheater that can reach suitable temperatures in …

Fluid Phase Separation Via Nanochannel Array, John Lee

Graduate Theses and Dissertations

Microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS) generate ideas and techniques for creating new devices at the micro/nano scale. This dissertation study designed a gas generator system utilizing nanochannels for phase separation that is useful for micro-pneumatic actuators, micro-valves, and micro-pumps. The new gas generator has the potential to be an integral part of a propulsion system for small-scale satellites. Nano/picosatellites have limited orientation capability partly due to the current limitations of microthruster devices. Development of a self-contained micro propulsion system enables dynamic orbital maneuvering of pico- and nano-class satellites.

Additionally, the new gas generator utilizes a high efficiency, green …

Temperature And Stress Analysis During Tank Decanting And Refilling Process, Zhe Liu

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

In the present work, an analytical expression for the temperature distribution of the cross-section of a natural gas transport tank is derived by time-matching Green’s Function method. The tank decanting process can produce a living temperature decrease inside the tank wall while the filling process can produce a large temperature increase. This behavior can cause damage to the inner layer of the tank. The damage occurs in the form of excessive stress in the wall which is combined mechanical stress and thermal stress. Therefore, thermo-elasticity analysis is another objective of the present work. A simplified mechanical model is established in …

Experimental Investigation Of Fischer-Tropsch Synthesis With A Modified Catalyst Support, Pawarat Bootpakdeetam

Mechanical and Aerospace Engineering Dissertations - Archive

Energy demand has been rapidly increasing in the last 30 years due to the population growth and high demand by industries. However, as natural energy sources are limited, they cannot meet this increased energy demand. Therefore, alternative energies have become an option to sustain current and future energy demands. One promising and reliable alternative energy is the Fischer-Tropsch synthesis (FTS), which is a gas-to-liquid (GTL) technology that converts syngas from a low-value feedstock, for example, from coal, biomass, or natural gas, into a high-value liquid hydrocarbon. In addition, FTS is a highly exothermic catalytic reaction that requires careful thermal management …

Reconfigurable Electrochemical Biosensor Enabled By Digital Microfluidic Devices, Ali Farzbod

Mechanical and Aerospace Engineering Dissertations - Archive

The increasing demand for improving the health care quality in developed countries with synchronous advances in the microfabrication of CMOS devices results in the emergence of the Lab-on-a-chip (LOC) field. The ultimate goal of LOC's is to achieve the complete integration of biomedical protocols, such as sample pre-processing and separation and analysis of biosamples on a chip. Electrowetting on dielectric (EWOD) as a distinctive digital microfluidic (DMF) is capable of manipulating droplets less than a microliter along the electrode arrays by applying AC voltages. EWOD chips, as microfluidic platforms, are inherently electrical and do not have to deal with problems …

A Two Stage Event Based Data Driven Controller For Improved Grasping Of An Artificial Hand, Christopher Abrego

Mechanical and Aerospace Engineering Dissertations - Archive

The human hand is one of the greatest (if not the greatest) tool known to mankind for grasping objects. So much so, that researchers have been investigating the development of artificial biomimetic hands in an effort to mimic their functionality and dexterity with the indent to apply the technology to various robotic platforms; ranging from end effectors for industrial pick-and-place robotics, to upper-limb prosthetics, to humanoids. There are certain features that make this endeavor challenging such as the mechanical design, actuation and sensorization, and functionality as well as the interaction from both the view point of interacting with an end …

Finite Element Analysis Of Composite Water Buffer Drum, Chinmay Shrikrishna S Godbole

Mechanical and Aerospace Engineering Theses - Archive

Composite materials offer many advantages for to many industries and developments based on their low density, corrosion resistance, and high strength to weight ratio. In addition, the use of composites allows for more design flexibility for products, the properties to meet specific design requirements, thus promoting better system oriented and cost-effective solutions. However, on a high performance equated basis, the economic incentive to use composite components can often be demonstrated based on their capability to reduce system and life cycle costs. Water buffer drum which is a pressure vessel holds a specified volume of fluid with desired temperature and pressure. …

On The Development And Integration Of Pneumatic Extrusion Module And A Methodology To Identify Process Parameters For Additive Manufacturing Using Machine Learning, Kashish Dhal

Mechanical and Aerospace Engineering Theses - Archive

Commonly used additive manufacturing platforms have a single extrusion module based on Fused Filament Fabrication (FFF) and their processing software generates G-Codes for this FFF module using defined process parameters. These platforms and software do not accommodate different processing modules such as viscous extruders or Direct Ink Writing (DIW). This research is focused on the development of a Pneumatic Extrusion Module (PEM) capable of dispensing viscous materials such as gels or slurries controlled through a digital pneumatic valve. A PEM is developed, integrated and its performance is evaluated on a multi-modality additive manufacturing platform in the MARS Lab. The operation …

Experimental Analysis Of A Single-Phase Direct Liquid Cooled Server Performance At Extremely Low Temperatures For Extended Time Periods, Gautam Gupta

Mechanical and Aerospace Engineering Theses - Archive

A data center is a centralized facility that we use for housing the computer systems and its related components such as high-end servers, redundant data connection and security controls. The next radical change in the thermal management of data centers is to shift from conventional cooling methods like air-cooling to direct liquid cooling (DLC) to deal with high thermal mass. The past few years have consistently seen wider adoption of direct liquid cooling because of its simplicity and high heat dissipation capacity. Passive single phase engineered fluid immersion cooling has several other benefits like better server performance, even temperature profile …

Quasi-One-Dimensional Scramjet Combustor Flow Solver Using The Numerical Propulsion System Simulation, Long Vu

Mechanical and Aerospace Engineering Theses - Archive

The flow field inside a scramjet engine combustor involves complex phenomena such as fuel-air mixing, combustion chemistry, and flow separation. In order to determine the properties of the flow along the length of the combustor, mass, momentum and energy balance equations are solved simultaneously using a numerical method. While a full three dimensional computational simulation gives detailed results with high order of accuracy, it demands a great amount of time and computational resource. A low order analysis produces a fast overall picture of the combustor operation which in turn provides valuable information suitable for the preliminary design process. This research …

Robot Motion Tracking Using Time-Of-Flight And Structured Light Sensors For Indoor Navigation, Karan Vishnu Rao

Mechanical and Aerospace Engineering Theses - Archive

Simultaneous localization and mapping for mobile robots has been an active research field for several years with focus on the problems of accuracy and dependability of the data from the robot's peripherals. The position estimates for mobile and industrial robots is usually achieved by using the information from the global positioning system in an outdoor environment and for indoor environment, technologies such as LiDAR sensors and Infrared (IR) camera based motion capture systems such as VICON (TM) are used. The main issue with these approach for indoor navigation is the monetary cost to associated with these technologies. The purpose of …

Comparison Of Carbon Steel And Composite Side Wall Of Light Rail Vehicle By Finite Element Analysis, Dilraj Singh

Mechanical and Aerospace Engineering Theses - Archive

A Railroad car is a vehicle used for carrying passengers and cargo. In the modern era, rail vehicles are designed as lightweight structures with the aim to minimize mass, operational energy demands, and CO2 emissions. Light rail vehicle is used at street level where they have direct contact with normal traffic and have a short distance between stations. In order to reduce dwell time at stops, and so, the vehicle can accelerate and deaccelerate easily, weight should be less and that is why low floor design is adopted these days. The sidewall is a crucial part of the car body …

Airflow Path And Flow Pattern Analysis Of Sub-Micron Particulate Contaminants In A Data Center With Hot Aisle Containment System Utilizing Direct Air Cooling, Satyam Saini

Mechanical and Aerospace Engineering Theses - Archive

The percentage of the energy used by data centers for cooling their equipment has been on the rise. With it has been the necessity for exploring new and more efficient methods, both from an engineering as well as business point of view, to contain this energy demand. The PCB boards are becoming more densely populated with multitude of smaller hardware on them, thereby, increasing its cooling requirements. Literature suggests that almost 40% of the total energy consumption in a typical Data Center is used for cooling purposes. Air cooling has always been the first choice for IT companies to cool …

Experimental Characterization Of Vertically Split Distribution Wet- Cooling Media Used In Direct Evaporative Cooling Of Data Center, Ahmed Al Khazraji

Mechanical and Aerospace Engineering Theses - Archive

When operating in direct evaporative cooling (DEC) mode, the amount of moisture added to a system can be controlled by frequently modulating water supply to the wet cooling media. Though many challenges arise due to geographical and site conditions, this concept can be applied to data centers to serve as a cost-effective alternative for maintaining the operating temperature of the facility at any weather condition. However, this method results in scale and mineral build up on the media because of an irregular water distribution. To prevent the scale formation, the operators allow the water supply continuously on the cooling media …

Investigation On Effective Modulus And Stress Concentration Factor Of 3d Reinforced Composite By Finite Element Analysis Method, Chandra Bhaskar Reddy Pittu

Mechanical and Aerospace Engineering Theses - Archive

Micromechanics of Composites aims to analyze the localized stresses inside any given constituents of the composite structure. This Thesis is focused on Calculating the effective modulus and the Stress concentration factor of the 3D straight Fiber Composite using Finite Element(FE). The compressive and a Shear response of a 3D Straight fiber composite comprising three directional E Glass Fibers reinforced in an epoxy matrix is analysed. This result is the 10% of overall Composite Ductility and a 10% of overall Shear displacement load in the orthogonal directions. FE calculations are reported to analyse the response of 3d reinforcement as of with …

Optimization Of Heating, Ventilation, And Air-Conditioning (Hvac) Chilled Water Plant Systems, Cliff Odhiambo Nudi

Mechanical and Aerospace Engineering Theses - Archive

Heating, Ventilation, and Air-conditioning accounts for about 60% of the total energy consumed in commercial facilities including office buildings, hospitals, retail stores, warehouses, campuses, manufacturing facilities, medical facilities, etc. As the cost of electricity and energy continue to rise, building owners and facility managers continue to witness a rise in the Total Cost of Ownership. Chilled water plant system is the largest consumer of energy in HVAC system consuming 75% of the total energy used in HVAC according to the Department of Energy. Operating chilled water plant systems at the recommended AHRI Standard 550/590 for performance rating of water chilling …

Design And Experimental Study Of Hydrostatic Thrust Air Foil Bearing, Myong Sok Song

Mechanical and Aerospace Engineering Theses - Archive

Oil-free bearing technology has several advantages over conventional oil-lubricated bearings. These advantages include high-speed operation, reduced weight, and increased reliability. Consequently, oil-free technology is expected to replace conventional bearings in a variety of applications. However, many challenges need to be addressed for widespread adoption of oil-free technology such as lower load capacity during start/stop and issues with controlling temperature. Thrust bearings, unlike their radial counterparts, are used for supporting axial loads and have become more important in recent years because of layout requirements other than double overhang configuration gaining consideration for specialized applications. Moreover, the requirements are demanding more extreme …

Simulation, Control And Testing Of A Custom 5-Dof Robotic Manipulator System, Roopak M. Karulkar

Mechanical and Aerospace Engineering Theses - Archive

Open chain manipulators are a well posed problem, however it was necessary to build a system customized to meet the needs of the Unmanned Ground Vehicle developed in the Aerospace Systems Laboratory. Considering that there are multiple such small ground vehicles, the main design constraint on the system was to be modular and lightwieght to enable quick swapping from both, a hardware and a software point of view. The purpose of this thesis is design, simulation and control a modular 5-Degree-of-Freedom manipulator with versatility in end effector configuration. This was achieved through the Robot Operating System which brings a high …

Experimental Investigation Of Thermophysical Properties Of Enhanced Nitrate Salt Nanofluids For Thermal Energy Storage (Tes) In Concentrated Solar Power (Csp) Systems, Vamsi Kiran Eruvaram

Mechanical and Aerospace Engineering Theses - Archive

The main source for energy production right now is from thermal, nuclear energy. But in the near future we might have crisis of coal so we need alternate renewable source for energy production the solution for that is sun, since solar energy is renewable and abundantly available. Concentrated solar power (CSP) technologies is one of the best solution to overcome this energy crisis, because it works from solar energy. If the CSP is incorporated with thermal energy storage (TES) we can produce energy even during night. TES with 15-hour storage capacity (Gemasolar) is already commercialized to operate a CSP plant …

Additive Manufacturing Process Investigation For The Fabrication Of Composite Scaffolds For Soft Tissue Application, Parimal Patel

Mechanical and Aerospace Engineering Theses - Archive

Additive manufacturing has been investigated and employed in the bio-medical domain for the fabrication of various devices and scaffolds. In various soft tissue engineering applications, multi-functional multi-material scaffolds are required for cell proliferation, structural integrity, bio-compatibility and tissue regeneration. In this research, an additive manufacturing methodology is developed to allow the fabrication of bio-composite scaffolds using a multi-modality in-house built platform. The researched materials for printing are Poly-L-Lactic Acid (PLLA) and a newly developed photo-curable radiopaque polymer called Rylar (Poly glycerole sebacate fumarate gadodiamide) mixed with a cross-linking agent Poly (Ethylene glycol) diacrylate (PEGDA). The developed methodology uses a Fused …

Reliability Of A 2.5d Tsv Package, Neha Vinayak Gaikwad

Mechanical and Aerospace Engineering Theses - Archive

In the recent years, the Through Silicon Vias (TSVs) are helping a huge variety of the 3D IC and the 2.5D IC packaging applications to try to fulfill their requirements of functionality and higher connectivity at the expense of lower power consumption and minimum heat dissipation. The TSVs offer great interconnect density, high device density, short connection paths, great space efficiency and high interconnect bandwidth. The basic difference between a 3D TSV package and a 2.5D TSV package is that the 2.5D one interconnects the dies side by side on a silicon interposer, over its entire length. The interposer, placed …

Mass Fabrication & Evolution Of Beads On Fiber, Kirthika Suresh

Mechanical and Aerospace Engineering Theses - Archive

In this work, we systematically explore the relation between the coating speeds and the finally formed liquid beads on fiber. The main focus of the paper lies with contact angle, length and height of beads on fiber and the fiber drawing velocity. For this purpose, free energy variation method is applied, based upon which the boundary conditions for the beads-on-fiber system and governing equations were re-derived. A combination of both, first and the second kind of the Legendre’s elliptical functions are used to determine the geometrical shape of the beads. Contact angle is extracted from the experimental data by using …

Predicting Mechanical Behavior Of 3d Printed Structures Using Mechanics Of Composites And Fracture, Megha Tangri

Mechanical and Aerospace Engineering Theses - Archive

Recently, additive manufacturing, or 3D printing as it is more commonly called, has taken a big leap in the manufacturing industry. This technology is rapidly moving from prototyping to manufacturing using metals, polymers, concrete and even composites. Unlike subtractive methods of manufacturing, additive manufacturing can be used to manufacture parts with highly directional mechanical properties. This research focuses on predicting tensile failure of 3D printed polymer structures in different raster orientations using composites lamination theory. Previously it was found experimentally that tensile strengths of 3D printed specimens decrease when raster orientations changes from 0° to 90°. The proposed model developed …