Mechanical Engineering Commons^™

Design And Development Of A Novel Test Method To Measure The Slipper / Swashplate Interface Fluid Film In A Positive Displacement Machine, Natalie A. Spencer

Open Access Theses

Although robust models of fluid film behavior between the slipper / swashplate lubricating interface in positive displacement machines have been developed, measuring this same fluid film thickness to a highly accurate degree inside a relatively unaltered axial piston unit has never been accomplished until now. A test method was created to close this gap in available data by measuring fluid film thickness between the slipper and swashplate in a 130cc axial piston pump. Precise knowledge of the gap height between the slipper and swashplate at various shaft angle locations during operation provides critical insight into machine behavior. The design, validation, …

A Numerical Procedure To Design The Optimal Axial Balance In External Gear Machines And Its Potential In Formulating Novel Efficient Design Solutions, Divya Thiagarajan

Open Access Theses

A novel numerical procedure to design the optimal axial balance in external gear machines (EGMs) has been formulated and developed in the present study. Lateral lubricating interfaces exist between the lateral bushes and the rotating gears in pressure compensated designs of EGMs and play a significant role in minimizing power losses arising from fluid shear stress and leakages from the gap. Moreover, lateral bushes in pressure compensated designs of EGMs perform significant functions of sealing the tooth space volumes while they transfer fluid from the inlet to the outlet port. ^ The losses from the lateral gap from these two …

A Web-Based Online Collaboration Platform For Formulating Engineering Design Projects, Sainath Varikuti

Open Access Theses

Effective communication and collaboration among students, faculty and industrial sponsors play a vital role while formulating and solving engineering design projects. With the advent in the web technology, online platforms and systems have been proposed to facilitate interactions and collaboration among different stakeholders in the context of senior design projects. However, there are noticeable gaps in the literature with respect to understanding the effects of online collaboration platforms for formulating engineering design projects. Most of the existing literature is focused on exploring the utility of online platforms on activities after the problem is defined and teams are formed. Also, there …

Optical Direct-Write Nanolithography Based On Self-Assembled Resist, Meghana Akella

Open Access Theses

Holographic display is being developed for next generation mobile phones. However, manufacturing of miniature gratings for the holographic projectors cost a few thousand dollars today, not making the concept practical for commercial purposes. In this thesis, we discuss the feasibility of self-assembled nanoparticles to manufacture holographic gratings cost-effectively and at the nanoscale. Using our approach, the gratings can be manufactured at the scale of 20nm and the cost per chip is expected to cost a few dollars.^ In this thesis, a hydrophobic SAM was used to modify the surface of silicon. Direct-write UV laser lithography was used for photothermal patterning …

Transverse Compression Of High-Performance Ballistic Fibers, Zherui Guo

Open Access Theses

High performance ballistic fibers have been in use for decades, specifically in protective applications against ballistic impact such as bulletproof vest layers and aircraft turbine engine fragmentation barriers. These high performance fibers have extremely high strength-to-weight ratios and high moduli of elasticity in the axial direction, making them extremely suitable for high impact situations. In particular, para-phenyleneterephthalamide (PPTA for short) fibers such as Kevlar^® and ultra-high-molecular-weight polyethylene fibers such as Dyneema^® are amongst the more popular high performance fibers in today's world. While the longitudinal mechanical response of these fibers have been extensively researched, their transverse mechanical response …

Cylinder Block / Valve Plate Interface Performance Investigation Through The Introduction Of Micro-Surface Shaping, Rene Chacon Portillo

Open Access Theses

Swash plate type axial piston machines are widely used positive displacement machines in different fields of industry ranging from aerospace, agriculture, automotive, heavy machinery, etc. Lubricating gaps are the main source of energy dissipation in axial piston machines. This type of machines have three lubricating interfaces: slipper/swash plate interface, piston cylinder and the cylinder block/valve plate interface. The cylinder block/valve plate interface being one of the most critical design elements of the machine. Extensive research has been done at Maha Fluid Power Research Center in Purdue University both to model this interface and to study the effects of micro-surface shaping …

Design, Development And Testing Of A Balance Board With Variable Torsional Stiffness And Time Delay, Denise Renee Cruise

Open Access Theses

The ability to balance and maintain upright posture can decline for a variety of reasons, such as aging and neuromuscular impairment. As the ability to balance declines, the risk of falling increases. Falls are a major cause of injury, and often lead to a dramatic decline in quality of life. Currently, to alleviate balance deficiencies, people participate in balance training, which most commonly refers to standing on an unstable balance board; the most common boards used are either passive wobble boards, or more advanced commercial systems such as the Biodex System SD ® or the Neurocom SMART Balance Master® . …

Laboratory Apparatus For Gas Turbine Combustion Development, Dustin Lee Cruise

Open Access Theses

The next generation of combustor technology will be required to meet the demands of a world more focused on greenhouse gases and global warming. Due to this new focus on emission control, combustors must produce less NO x , while operating in a higher pressure environment that is more prone to combustion instabilities.

This work focuses on the development of a lab and combustor that will be used for the next generation combustor development. The lab development includes layout and organization, facilities, measurement and instrumentation, automation of the testing process, and an imaging tool for diagnostics.

A Lean Direction Injection …

Design Of Optical Access For The Application Of Laser Doppler Velocimetry In A Low Specific Speed Centrifugal Compressor, Bryce Ashton Heckaman

Open Access Theses

The objective of this research has been to design optical access for the application of laser Doppler velocimetry (LDV) in a low specific speed centrifugal compressor. The ability to acquire non-intrusive flow measurements will provide valuable insight into tip leakage flow, secondary flow, and impeller/diffuser interactions within the centrifugal compressor. The current research facility houses a new low specific speed centrifugal compressor which design is based off a compressor that would be installed as the last stage of a high-pressure compressor.

The LDV optical access has been designed and includes two fused silica windows that are housed in stainless steel …

Optimal Control Of Unknown Nonlinear System From Inputoutput Data, Xin Jin

Open Access Theses

Optimal control designers usually require a plant model to design a controller. The problem is the controller's performance heavily depends on the accuracy of the plant model. However, in many situations, it is very time-consuming to implement the system identification procedure and an accurate structure of a plant model is very difficult to obtain. On the other hand, neuro-fuzzy models with product inference engine, singleton fuzzifier, center average defuzzifier, and Gaussian membership functions can be easily trained by many well-established learning algorithms based on given input-output data pairs. Therefore, this kind of model is used in the current optimal controller …

High Temperature Flooded Expansion For Solar Thermal Power Generation, Nelson Alexander James

Open Access Theses

Even though solar power usage has seen rapid growth over the past decade, fossil fuel generation sources are still generally a less expensive means of producing power. The Liquid-Flooded Ericsson Cycle (LFEC) was investigated as a high efficiency power cycle for reducing the cost of concentrated solar power (CSP) plants and helping to address this cost disparity. High temperature flooded expansion was identified as one of the main challenges in regards to utilizing the LFEC as a power cycle. Thermodynamic models were developed to help assess the performance of the LFEC and a load stand was constructed to test a …

Integration And Implementation Of High-Voltage Energy Storage Sub-System For A Parallel-Through-The-Road Plug-In Hybrid Electric Vehicle, Bilwa A. Jadhav

Open Access Theses

With research showing an alarming rate of increase in global warming and thus causing dangerous instabilities in the weather, a strong push has been initiated to reduce greenhouse gas emissions. Transportation being one of the top offenders in greenhouse gas emissions, has led the drive for improving the efficiency of the modern automobile. One of the current strategies for reducing the emissions produced by the transportation sector is hybrid vehicles powered from both a fuel such as gasoline, diesel, or hydrogen; and electricity. This merger has proven to be effective at decreasing harmful emissions including, carbon dioxide (CO 2 ) …

Fundamental Design Principles Of Novel Mems Based "Landau" Switches, Sensors, And Actuators : Role Of Electrode Geometry And Operation Regime, Ankit Jain

Open Access Dissertations

Microelectromechanical systems (MEMS) are considered as potential candidates for "More-Moore" and "More-than-Moore" applications due to their versatile use as sensors, switches, and actuators. Examples include accelerometers for sensing, RF-MEMS capacitive switches in communication, suspended-gate (SG) FETs in computation, and deformable mirrors in optics. In spite of the wide range of applications of MEMS in diverse fields, one of the major challenges for MEMS is their instability. Instability divides the operation into stable and unstable regimes and poses fundamental challenges for several applications. For example: Tuning range of deformable mirrors is fundamentally limited by pull-in instability, RF-MEMS capacitive switches suffer from …

High Fidelity Simulations Of Electrokinetic Phenomena In Microfluidic Devices, Qian Li

Open Access Dissertations

Electroosmotic flow with electrokinetic effects is the primary method of fluid handling in micro-total analysis systems. Under external applied electric fields, electrokinetic micro-devices allow for innovative functionality in a wide range of microfluidic applications including sample injection, separation, rapid micromixing, and miniaturized chemical and biochemical analysis and detection. This dissertation focuses on simulations of two electrokinetic phenomena, isotachophoresis (ITP) and electrokinetic instability (EKI). A set of coupled governing equations including the incompressible Naiver-Stokes equations, Nernst-Planck transport equations and a charge conservation equation are solved in the simulation. A multiblock in-house solver based on high-order finite difference schemes is developed to …

Novel Energy Efficient Electrohydraulic Steer-By-Wire Technology, Naseem Daher

Open Access Dissertations

Improving energy efficiency, productivity, safety, and comfort of mobile machines is of utmost priority to original equipment manufacturers, suppliers, and consumers given the escalating fuel prices and increased awareness to the environment and workplace hazards. A major breakthrough in the realm of high power motion control is pump displacement controlled (DC) actuation, which does away with hydraulic valves for motion control and uses a variable displacement pump as both a flow source and final control element, thus eliminating throttling losses associated with hydraulic control valves. This work deals with researching and implementing DC technology for realizing the steering function of …

Experimental And Numerical Investigation Of The Mechanism Of Blast Wave Transmission Through A Surrogate Head, Yi Hua, Praveen Akula, Linxia Gu, Jeff Berg, Carl A. Nelson

Department of Mechanical and Materials Engineering: Faculty Publications

This work is to develop an experiment-validated numerical model to elucidate the wave transmission mechanisms through a surrogate head under blast loading. Repeated shock tube tests were conducted on a surrogate head, i.e., water-filled polycarbonate shell. Surface strain on the skull simulant and pressure inside the brain simulant were recorded at multiple locations. A numerical model was developed to capture the shock wave propagation within the shock tube and the fluid-structure interaction between the shock wave and the surrogate head. The obtained numerical results were compared with the experimental measurements. The experiment-validated numerical model was then used to further understand …

Aerodynamic Study Of Forces Due To Wind Velocity And Angle Of Attack On Parabolic Solar Troughs, Brian Northshield

Doctoral Dissertations and Master's Theses

Scant literature exists of the atmospheric effects on parabolic solar troughs. The technology is relatively new, so supporting studies by consequence are as well.

This study examines the effects of wind at various speeds, with various angles of attack on parabolic solar troughs. This begins by picking up on previous study, corroborating previously found data, then introduces new angles of attack. The model includes the presence of the solar tube where other studies omit.

The purpose of this study is to build a data set which is useful for structural consideration. During the course of this study, it was found …

Simple Fall Criteria For Mems Sensors: Data Analysis And Sensor Concept, Alwathiqbellah Ibrahim, Mohammad I. Younis

Mechanical Engineering Faculty Scholarship

This paper presents a new and simple fall detection concept based on detailed experimental data of human falling and the activities of daily living (ADLs). Establishing appropriate fall algorithms compatible with MEMS sensors requires detailed data on falls and ADLs that indicate clearly the variations of the kinematics at the possible sensor node location on the human body, such as hip, head, and chest. Currently, there is a lack of data on the exact direction and magnitude of each acceleration component associated with these node locations. This is crucial for MEMS structures, which have inertia elements very close to the …

Automated Landing Site Determination For Unmanned Rotocraft Surveillance Applications, Justin Keith Mackay

Theses and Dissertations

Unmanned air vehicles have been increasing in their autonomous capabilities. This research furthers these capabilities by focusing on the automation of landing site determination for rotorcraft in urban environments. Automated landing saves energy and allows the aircraft to choose areas that are safe for people and the aircraft. Two methods are used to gather information about the terrain of potential landing sites. One method is 3D reconstruction from multiple camera images. The other method uses a range sensor to reconstruct the terrain. Both of these methods create an inertial terrain map of the environment in the form of a point …

Early Damage State Criterion From A Fault-Seeded Helicopter Gear Using Acoustic Emission And Neural Networks, Rudy L. Baum

Doctoral Dissertations and Master's Theses

In response to five failures since 2008 of the tail gearbox of multiple models of Sikorsky's H-60 helicopter, acoustic emission (AE) data collected from a rotating gearbox test stand at the Naval Air Station in Patuxtent River, MD, was used to monitor the initiation and propagation of a flaw from an electro-discharge machined (EDM) notch seeded on the face of a gear tooth. A period of testing was considered which spanned ~300,000 seconds or ~83 hours and culminates to a damage state such that a flaw has initiated on both ends of the EDM notch. AE data was analyzed for …

Energy Conservation By Intermittently Recirculating And Aerating An Aquaponics System With An Airlift, Bjorg Magnea Olafs

Doctoral Dissertations and Master's Theses

An airlift device providing aeration and circulation was designed to reduce electrical power requirements for aquaponics by eliminating the need for a water pump. The airlift performed better than predicted and achieved water flow rates of 10 L/min at 25 °C, in comparison to the theoretical design performance 2.65 L/min.

Koi (Cyprinus carpio) and sweet basil (Ocimum basilicum) were cultured for five weeks in two identical aquaponics systems. The system was located indoors and consisted of a fish tank, a sump tank, and a soil-free growth media bed under artificial lighting. The total water volume in each system was 230 …

Elastic Energy Absorption Via Compliant Corrugations, Sean S. Tolman

Theses and Dissertations

Elastic absorption of kinetic energy and distribution of impact forces are required in many applications. This may be achieved through the use of compliant corrugations. An innovative padding concept is investigated for such applications. Also, recent attention given to the potential for using origami in engineering applications may provide new corrugation configurations that are advantageous for energy absorption and force distribution. This work explores three areas related to these concepts.First, the parameters of a compliant, corrugated padding concept are investigated using Finite Element Analyses (FEA) and physical testing. The shape of the corrugation cross section is explored as well as …

A Computational Hybrid Method For Self-Intersection Free Offsetting Of Cad Geometry, Garrett Clark Bodily

Theses and Dissertations

Surface offsetting is a valuable tool used in Computer Aided Design (CAD). An offset surface is a collection of points that are at a constant distance from another surface. An offset surface is created in CAD by selecting a surface and then specifying the distance that the surface is to be offset. If a surface is selected and a distance of D is specified, then the resulting offset surface should always be distance D from the original surface. The surface offset tool can be used for many applications. Modeling of composites or other layered manufacturing processes rely heavily on offset …

Articulated Spine For A Robot To Assist Children With Autism, Brandon M. Norton

Theses and Dissertations

Autism spectrum disorder (ASD) affects about 1.5 million individuals in the US alone. The consequences of ASD affect families, caregivers, and social structures. This thesis adds to a growing group of people performing research on mitigating the effects of autism through robotics. Children with ASD tend to interact with robots more easily than with other humans. The goal of robotic therapy is not to help children interact with robots, but to generalize the behavior to humans. An articulated spine is a key to human emotional expression through shaping, weight shifting, and flow. Despite this importance, this feature is all but …

Investigation Of Potential Benefits Of Revising Exception 1 Under Florida Building Code, Energy Conservation, Section 101.4.7.1.1 Duct Sealing Upon Equipment Replacement, Florida Solar Energy Center, Janet Mcilvaine

FSEC Energy Research Center®

Section 101.4.7.1.1, Duct sealing upon equipment replacement (Mandatory), of the 2012 Supplement to the Florida Building Code, Energy Conservation went into effect briefly in 2013. The new section required sealing of accessible ducts at the time of HVAC equipment replacement. Exception #1 however, eliminates the requirement for ducts in conditioned space, and by doing so, effectively eliminates the sealing requirement for building cavities in conditioned space that are used as air distribution paths. However, test results show that these building cavities are often connected to adjacent unconditioned spaces, in effect they are not really in the conditioned space because they …

Analysis Of Different Techniques For Improving Performance Of Flat Plate Solar Collectors For Fruits Drying, Godfrey Mbabaye

Tanzania Journal of Engineering and Technology (TJET)

Fruits drying had become a broader technology in fruits and vegetables value addition. The technology is reported to be a promising way of drying without incurring higher cost but its adaptation has not been feasible in rural areas. Solar dryers have been developed but its poor performance limits its applicability. In this study, several techniques for modifications of traditional solar collector were addressed. It was observed that, varying collector designs in different techniques, a range of collector performances can be archived. The research shows that, collector efficiency can be improved by 9.6% when employing double duct counter flow compared to …

Investigating The Potential Of Residential District Energy, Nelson Fumo, Vicente Bortone, Juan Zambrano, Aleyani Zambrano

Mechanical Engineering Faculty Publications and Presentations

The International District Energy Association claims that district energy: improve energy efficiency, enhanced environmental protection, fuel flexibility, ease of operation and maintenance, reliability, comfort and convenience for customers, decreased life-cycle costs, decreased building capital costs, and improved architectural design flexibility. In the U.S.A. most of the installed district energy systems are found in buildings such as colleges and universities, healthcare installations, government installations, airports and community utilities, as well as industry. All these applications have proved the advantages of district energy. However, for typical neighborhoods in small cities in the U.S.A., the dispersion of the dwelling imposes additional challenges to …

Vehicle Multi-Pass Rut Volume And Mobility Power Study, William W. Barbour

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

This paper presents the relationship between applied power by a wheeled vehicle to soil and the rutting effects. Specifically, a strong positive relationship was found between cumulative applied power and total rut volume across multiple passes by the vehicle over the same tracks. Field-testing was conducted using a high-mobility multi-purpose wheeled vehicle (HMMWV) and two distinct soil types. Sensors on the vehicle measured torque and angular velocity of each of the four wheels, from which applied power was calculated. A rut profile meter was used to document the shape of the rut after set numbers of passes and this profile …

Initial Testing Of A Unitary Hvac System Advanced Control Module, Florida Solar Energy Center, Richard Raustad

FSEC Energy Research Center®

Testing of a unitary HVAC system advanced control module and the results.

Are Undergraduate Gpa And General Gre Percentiles Valid Predictors Of Student Performance In An Engineering Graduate Program?, Larry L. Howell, Carl D. Sorenson, Matthew R. Jones

Faculty Publications

While both subjective measures and quantitative metrics play an important role in admissions decisions, quantitative metrics are amenable to critical analysis using the tools of academic analytics. The hypotheses that motivated this study are: 1. Can an applicant’s undergraduate grade point average (UGPA) and scores on the Graduate Records Examinations (GRE) be used to accurately predict the performance of the applicant in a graduate mechanical engineering program? 2. Is a single construct based on these quantitative predictive metrics a valuable tool in efficiently making admissions decisions? This study analyzed the relationship between quantitative predictive metrics, available at the time of …