Engineering Commons^™

Optimal Design And Control Of A Lower-Limb Prosthesis With Energy Regeneration, Holly E. Warner

ETD Archive

The majority of amputations are of the lower limbs. This correlates to a particular need for lower-limb prostheses. Many common prosthesis designs are passive in nature, making them inefficient compared to the natural body. Recently as technology has progressed, interest in powered prostheses has expanded, seeking improved kinematics and kinetics for amputees. The current state of this art is described in this thesis, noting that most powered prosthesis designs do not consider integrating the knee and the ankle or energy exchange between these two joints. An energy regenerative, motorized prosthesis is proposed here to address this gap. After preliminary data …

A Psa Process For An Oxygen Concentrator, Aaron A. Moran

ETD Archive

Oxygen is used in a variety of chemical processes and for medical purposes throughout the world. Pressure swing adsorption (PSA) has become a viable alternative to cryogenic distillation for the separation of oxygen from air with the development of advanced adsorbents like zeolites. PSA processes are inherently complex because it is a dynamic process. Efficient operation of a PSA process is necessary in order to utilize the capacity of the adsorbent as much as possible and reduce the power requirements of the process.In this thesis, a novel zeolite adsorbent was utilized in a PSA process for oxygen generation with the …

Quikchill : Thermoelectric Water Cooler, Franz Louie Chua, Brandon Ohara, Rachel Reid, Bernadette Tong

Mechanical Engineering Senior Theses

Motivated by the increasing residential energy utilization projections and the fact that water and ice dispensers consume 20% of total refrigerator energy, a thermoelectric water chiller was designed to provide a more energy efficient alternative. Implementing the chiller under the sink provides a convenient means to source cold, filtered water, thereby eliminating the need for water and nice dispensers as well as filtering pitchers. The cooling chamber design integrates thermoelectric modules (TEMs), which operate on the Peltier effect to cool filtered water down to 14 [degrees] C. The implementation of TEMs reduced current dispenser energy consumption by 82.4%, from 91 …

Design, Fabrication, And Analysis Of A 3u Cubesat Platform, Todd Chun-Van Osdol, Charles Dorsey, Jake Hedlund, Thomas Hoye, Owen Jacobs, Kadja Klarreich-Giglio, Elliott Martin, Michael Ruiz, Michael Schlesselmann, Zachary Singh

Mechanical Engineering Senior Theses

The goal of this project is to develop a 3U CubeSat nanosatellite bus capable of short duration technology verification experiments while providing compelling handson student education opportunities. This 3U CubeSat platform has been prototyped by the design team in order to demonstrate its capabilities. This spacecraft, the Unspecified Payload Active Attitude Control Nanosatellite (UPAACN), is designed to perform a 3-6 month technology verification experiment for a NASA test component and an SCU single-axis attitude control system (AACS) in Low Earth Orbit (LEO). This project builds upon the flight heritage of SCU's Robotic Systems Laboratory (RSL) and improves its satellite development …

Formula Electric : Powertrain, Mark Allison, Bryan Bidwell, Stuart Hopson, Jackson Smith, Carlos Streegan, Dominic Villa

Interdisciplinary Design Senior Theses

The Santa Clara Formula Electric team designed, and manufactured a powertrain for an electric racecar according to the rules prescribed by the SAE International Formula Electric competition. The powertrain is divided into subsystems: the battery pack, battery pack cooling system, motor controller, and the motor. The battery pack was constructed, but full electrical connection of all cells were not made. The pack was not integrated with the motor and motor controller. In addition, due to time constraints, extensive testing could not be completed.

Project Omoverhi : Low-Cost, Neonatal Incubator, Richard Fong, Guillermo Gallardo, William Jeffery, Danny Maeda, Gabriel Romero

Interdisciplinary Design Senior Theses

Project Omoverhi, since its beginning in 2010-2011, has been focused on creating an incubator that has the capability of operating completely off grid. This year the project has been focused on redesigning the original system to reduce the cost to approximately $1000. In addition to this we have designed and implemented a control system that enables the user to set a desired temperature which can be maintained to within 1 degree Celsius. Before the project is able to be completed further work must be done. The thermal storage system that was initially proposed by the original team still needs to …

Thermoelectric Cookstove, Christine Horman, Matthew Lee, Mark Wagner

Mechanical Engineering Senior Theses

A fuel efficient cookstove tailored to the needs of Nicaraguan small business owners that incorporated insulation and thermoelectric power generation was built and validated. There is a 4 inch layer of pumice rock insulation around the combustion chamber, which significantly reduces convective heat losses to the environment. The stove's ventilation system is powered by the electricity generated by thermoelectric generators. Preheated air is forced into the combustion chamber, which increases the combustion efficiency, reducing the fuel consumption and the harmful smoke produced. Through various testing methods, we found that the controlled airflow to the charcoal fuel allows the stove to …

The Squad : Santa Clara Quadrotor Autonomous Drone, Jacob Adams, Peter Baumgartner, Mark Johnson, Michael Mccormick

Mechanical Engineering Senior Theses

We have constructed a quadrotor unmanned aerial vehicle (UAV) that could be used to supplement emergency response personnel, including police and military, when in the field. The SQUAD focused primarily on designing and constructing a sound structure for the UAV, as well as beginning controls work, which will be continued by another team at a later date. This quadrotor UAV has a video camera to provide a live video from its point of view to the user. It carries a global positioning system (GPS) to provide information on its location, and to navigate to waypoints in the immediate area. The …

Cerberus : A Human Powered Vehicle, Colin Austin, Miles Graugnard, Max Herrmannsfeldt, Dane Kornasiewicz, Leif Kjos, Terra Oldham, Toban Platt, Theodore Schapp, Sean Smith

Mechanical Engineering Senior Theses

A recumbent trike was designed and built for the ASME Human Powered Vehicle Challenge held at San Jose State University in April of 2013. The vehicle was designed to be low cost for use by commuters and as primary transportation in developing countries. The vehicle placed 11th overall in the competition out of 29 teams, and scored 8th in the innovation event, which was its best ranking out of the 5 individual events.

Phase Change Material In Automated Window Shades, Quinlan Adler, Jake Gallau, Alexander Zatopa, Ali Nash

Mechanical Engineering Senior Theses

The purpose of this report is to detail the development process for a phase change material window shading system, which stores solar thermal energy and later releases it indoors to provide nighttime space heating. To do this, wax-filled louvers with thermally absorptive front faces were developed and outfitted with a control system, which utilized historical weather data to orient the louvers to specific solar azimuthal angles, thus maximizing the thermal absorption. The system was tested against other common window treatments in a pair of thermally comparable testing structures, and was found to provide energy savings as high as 50%.

Icarus : Aerial Recording System, Jim Cochran, Nick Xydes, Jimmy Erskine, Audrey Kocmond

Mechanical Engineering Senior Theses

The goal of Project ICARUS is to create an aerial videography system that is easy to set up, inexpensive, portable, and highly adaptable to any situation. This is accomplished by using a balloon mounted camera rig that is grounded by a number of winches. This system is able to obtain a higher altitude than similar systems and is much more cost effective because the system can be applied to a number of circumstances such as sporting events, disaster relief, wildlife videography, and aerial monitoring, to name a few. The ICARUS system allows the user to control the position of an …

Damage Characterization And Analytical Modeling Of Quasi-Statically Indented Graphite/Epoxy-Honeycomb Core Composite Sandwich Stru, Abhendra K. Singh

Mechanical and Aerospace Engineering - Dissertations

The research conducted for this dissertation focused on understanding the nature and extent of barely visible impact damage (BVID) in composite sandwich structures. This was part of a larger research effort that included studies on the influence of BVID on the compressive strengths and failure modes of composite sandwich structures. In this dissertation, the nature and extent of BVID is studied in aluminum honeycomb core sandwich panels with eight and sixteen ply, quasi-isotropic, graphite/epoxy face sheets. The damage in the sandwich structure is created quasi-statically using spherical indentors of two different sizes. Apart from the face sheet thickness and indentor …

Microstructural-Based Modeling Of Electrical Percolation In Polymer Nanocomposites, Neelima Yellepeddi

Theses and Dissertations

Polymer nanocomposites (PNCs) represent a radical alternative to conventional filled polymers or polymer blends. In contrast to conventional composites, where the included phase is on the order of micrometers, PNCs are defined as those that have discrete constituents on the order of a few hundred nanometers. The value of PNCs is not solely based on tailoring mechanical properties, as in traditional composite design and manufacture, but rather on the potential for the design and optimization of multi-functional properties. There is major interest in these polymeric materials embedded with a conductive nanoscale filler. This is due to the possibility of designing …

Storwatts: Compressed Air Energy Storage System, Michael Biederer, John O'Malley Iii, Joseph Burke, Matthew Komo

Mechanical Engineering Senior Theses

The current problem with energy backup and grid stabilization systems is that both either require fuel and constant maintenance, such as diesel generators, or cannot perform at their peak operation and need constant replacement, like batteries. Our solution and the goal of the StorWatts senior design project was to design and create a small-scale compressed air energy storage system to be used in place of traditional energy backup and grid stabilization systems. The StorWatts system does not need fuel in order to store and generate power and therefore does not require constant refueling and maintenance. It also can work in …

Project Omoverhi : A Thermal Storage Solution, Peter J. Graham, P. Alexander Kranenburg, Tor C. Krog, Cameron C. Schwab

Mechanical Engineering Senior Theses

One principal energy source that is underutilized in the world today is solar energy. While the United States has tried to make a push for reusable and 'green' energy sources, these sources are frequently overlooked in developing nations. While the set up costs of solar energy may be expensive due to installation and the high cost of certain parts, the savings over time is well worth the initial cost. In many developing nations large areas of the country are off of the power grid or have inconsistent power. One way to help people living in these areas is by introducing …

Nanosatellite Fabrication And Analysis, Sam Harrison, Patrick Scott, Victor Zapien

Mechanical Engineering Senior Theses

The advancements in technologies used in the aerospace industry have allowed universities to experiment with and develop small-scale satellites. Universities are taking advantage of the relatively low development costs of nanosatellite programs to give students experience in the field of spacecraft design. The purpose of Santa Clara University's team, Nanosatellite Fabrication and Analysis, is to create a process to expedite the design, analysis, and fabrication phase of nanosatellite structures for students working on future satellite missions. The objective is to design four baseline nanosatellite structures to accommodate a range of potential missions where the designs are simple enough to be …

Design And Analysis Of A Low-Profile Two-Axis Solar Tracker With Hybridized Control, Laughlin Barker, Criselle Olaes, Joseph Valdez, Darcy Marumoto

Mechanical Engineering Senior Theses

The adoption of solar power technologies throughout the world is increasing rapidly. Solar trackers are a necessary component in Concentrated Solar Power (CSP) applications and have also shown up to 46% per annum energy increase in photovoltaic (PV) panels when compared with fixed mounted panels. To resist wind forces, trackers typically incorporate heavy structural components and reinforced concrete foundations. Thus, the manufacture and installation of trackers is costly due to their size, weight, and careful consideration of geological conditions. This work presents a new solar tracker design for use with concentrating solar power and photovoltaic panels. The tracker is comprised …

Solar Powered Water Purification System, Alina Carlson, Reece Kiriu, Andrew Nosé, Christopher Sugii, Erin Taketa, Alex Tamai

Mechanical Engineering Senior Theses

Santa Clara University's 2011-2012 Solar-Powered Water Purification System team is developing a solution to create a water distillation system, heated by solar troughs and solely powered by photovoltaic (PV) panels that can produce clean, drinkable water. This device would balance cost and efficiency to be marketable to lower-income locations, such as developing countries that suffer from shortages of clean water. In accomplishing this, the team will ensure that the system is sustainable and requires minimal maintenance.

Design Of A Liquid Fuel Injector For Alternative Fuel Studies In An Atmospheric Model Gas Turbine Combustor, John Stevenson

Honors Theses

A new liquid-fuel injector was designed for use in the atmospheric-pressure, model gas turbine combustor in Bucknell University’s Combustion Research Laboratory during alternative fuel testing. The current liquid-fuel injector requires a higher-than-desired pressure drop and volumetric flow rate to provide proper atomization of liquid fuels. An air-blast atomizer type of fuel injector was chosen and an experiment utilizing water as the working fluid was performed on a variable-geometry prototype. Visualization of the spray pattern was achieved through photography and the pressure drop was measured as a function of the required operating parameters. Experimental correlations were used to estimate droplet sizes …

Investigation Of The Design Of A Bistable Micro-Chemical-Mechanical Device Utilizing Lateral Buckling, Susan Lyn Barnes

Honors Theses

The Gracias Laboratory at Johns Hopkins University has developed microgrippers which utilize chemically-actuated joints to be used in micro-surgery. These grippers, however, take up to thirty minutes to close fully when activated biochemicals in the human body. This is very problematic and could limit the use of the devices in surgery. It is the goal of this research to develop a gripper that uses theGracias Laboratory's existing joints in conjunction with mechanical components to decrease the closing time. The purpose of including the mechanical components is to induce a state of instability at which time a small perturbation would cause …

Non-Collocation Problems In Dynamics And Control Of Mechanical Systems, Timothy M. Obrzut

ETD Archive

Characteristics of mechanical systems with non-collocated sensors and actuators are investigated. Transfer function zeros location as a function of sensor position, zero-pole interlacing, and re-location of zeros are discussed in a context of presented examples. Some of the presented examples involving non-collocation are supported by experimental data. A case study involving a high speed machining spindle is examined. The control problems associated with non-collocation are studied along with the methods to solve them

High-Level, Product Type-Specific Programmatic Operations For Streamlining Associative Computer-Aided Design, Nathan W. Scott

Theses and Dissertations

Research in the field of Computer Aided Design (CAD) has long focused on reducing the time and effort required of engineers to define three dimensional digital product models. Parametric, feature-based modeling with inter-part associativity allows complex assembly designs to be defined and re-defined while maintaining the vital part-to-part interface relationships. The top-down modeling method which uses assembly level control structures to drive child level geometry has proved valuable in maintaining these interfaces. Creating robust parametric models like these, however, is very time consuming especially since there can be hundreds of features and thousands of mathematical expressions to create. Even if …

Design And Manufacturing Of Functionally Graded Materials With Polymer Chain And Nano-Reinforcement Orientation For Compressive Applications, Sanjay Varma Kalidindi

Theses and Dissertations - UTB/UTPA

Functionally Graded Materials for compressive applications were designed and manufactured by tailoring the properties of Pure Polyethylene (PE) and Vapor Grown Carbon Nanofiber (VGCNF) Reinforced PE Composites. Properties of NRPC have been extensively studied. Properties are dependent on parameters such as the reinforcement/matrix interaction; reinforcement volume fraction, orientation, dispersion, and packing, and the final matrix microstructure. However, there is limited literature on their properties under compression loading. Compression strength studies for high density PE reinforced with VGCNF for different fiber volume fraction (0%, 5%, 10% and 15%) were carried out. The role of interface and alignment was studied. Samples were …

Electrorheology Of Fullerene Suspensions, Maricela Lizcano

Theses and Dissertations - UTB/UTPA

Electrorheological fluids are suspension materials whose rheological behavior changes with an applied voltage. In particular, the material changes from a fluid to a solid behavior with an applied voltage and reverses to its original state when the voltage is removed. This function classifies ER fluids as smart materials. ER fluids may be developed and used as mechanical devices with no mechanical parts such as pumps, actuators, and dampers. Until recently, research was concentrated with micro-particle suspension fluids. This research project investigates the electrorheology of carbon nano-particle suspension.

Comparison Of Sliding Mode And State-Feedback Control Applied To A Partially Treated Actively Constrained Layer Damped (Acld) Beam, Jose J. Rodriguez

Theses and Dissertations - UTB/UTPA

In this research, a sliding mode control (SMC) was utilized in the control of a partially treated, actively constrained layer damped (ACLD), Timoshenko beam model. The resulting vibration control was compared to the vibration control achieved by a state-feedback linear quadratic regulator (LQR) for several loading conditions. An observer was designed and model order reduction (MOR) was performed to achieve a simplified, efficient, and more controllable finite element system model. As a result of model simplification, modeling errors in the form of unstructured uncertainties were introduced into the system. It was determined that the SMC and LQR achieved similar vibration …

Composite Mechanical Property Enhancement Through The Use Of Y-End Shaped Short Fibers, Jin Tan

Theses and Dissertations - UTB/UTPA

This study uses Finite Element Analysis (FEA) to predict the mechanical property enhancement of the composites reinforced by end-shaped short fibers with different aspect ratios and volume fractions at microscale. Fibers used include conventional straight short fibers (CSSF), dumbbell-end shaped short fibers (DSSF), bone-end shaped short fibers (BSSF) and Y-end shaped short fibers (YSSF) with various lengths and angles. The critical distances between neighboring fiber ends for FEA modeling were theoretically deduced and numerically verified. This study has never been done before and the results fill a gap to this field.

In conclusion, planar-end Y-shaped short fiber reinforced composites showed …

Extension Of Stereolithography Mold Life Using Gas-Assisted Injection Molding, Dilip Bose Ramalingam Nagarajan

Theses and Dissertations - UTB/UTPA

Stereolithography (SL) molds show great promise for injection molding of limited number of parts, greatly reducing the time to product and production cost. However, they present challenges to designers because of their strength, thermal characteristics and shorter lifetimes compared to metal molds. Gas-assisted injection molding (GAIM) has been used to alleviate the problems of distortion and thermal damage. The use of GAIM makes it possible to produce a large number of parts compared to conventional injection molding in epoxy molds with higher quality. In this research solid models of the mold with different part geometry were created using CAD and …

Development Of A Novel Microreactor For Improved Chemical Reaction Conversion, Yu Liang

Doctoral Dissertations

Microreactors have been widely studied over the past two decades for different chemical reactions, to develop new analytical capabilities, and to obtain high mixing performance in the reactors. The main objectives of this work are to investigate the effect of different microchannel structures on the fluid properties and mixing behavior in microreactors, and to design, fabricate, and test a novel microreactor for higher conversion in a chemical reaction. The development of this novel microreactor is intended to provide a valuable guideline in achieving enhanced chemical mixing and to make available a solid research base for optimization of the yield of …

The Development Of An Accelerated Testing Facility For The Study Of Deposits In Land-Based Gas Turbine Engines, Jared Wilfred Jensen

Theses and Dissertations

Turbine engine efficiency modeling depends on many parameters related to fluid dynamics and heat transfer. Many of these parameters change dynamically once the engine enters service and begins to experience surface degradation. This thesis presents a validation of the design and operation of an accelerated testing facility for the study of foreign deposit layers typical to the operation of land-based gas turbines. It also reports on the use of this facility in an effort to characterize the change in thermal resistance on the surface of turbine blades as deposits accumulate. The facility was designed to produce turbine deposits in a …

Fatigue Of Drill Pipes Used In Horizontal Directional Drilling, Feibai Ma

Doctoral Dissertations

Fatigue is the most common cause of mini-HDD drill rod failure. It can occur at stress levels far below the normal operating stress in most drill stem components. Fatigue failures occur because the drill rod, after it has been forced into a curved path, undergoes a cyclic bending stress oscillating from tension to compression in concert with the other stress components caused by torque, thrust, or pullback.

When a rod breaks underground, there is considerable extra cost caused by the delay in “fishing” out the broken rod as well as the cost of replacing the rod. On the other hand, …