Engineering Commons^™

An Investigation Of Process Parameters To Optimize The Fiber Diameter Of Electrospun Vascular Scaffolds Through Experimental Design, Steffi Wong

Biomedical Engineering

No abstract provided.

Characterization And Analysis Techniques Of A Dynamic In Vitro Blood-Brain Barrier Model, Ryan Everett Woodhouse

Biomedical Engineering

The blood-brain barrier (BBB) is responsible for maintaining the sensitive environment required by the brain. Although the BBB is necessary for proper functioning of the brain, it acts as an obstacle for doctors attempting to treat neurological disease. For a drug to act upon the brain, it must first pass through the discriminating BBB. For this reason, much research has been performed in recent years in order to create an in vitro model of the BBB on which drugs targeted for the central nervous system may be tested. The main goal of this project is to create an in vitro …

The Development And Validation Of A Finite Element Model Of A Canine Rib For Use With A Bone Remodeling Algorithm., Scott J. Sylliaasen

Master's Theses

Studies are currently being performed to determine the effects of bisphosphonate treatments on the structure and density of bone tissue. One of the pathways for gaining a better understanding of the effects of this and other treatments involves creating a computer simulation. Theory suggests that bone tissue structure and density are directly related to the manner in which the tissue is loaded. Remodeling is the process in which bone tissue is resorbed in areas of low stress distributions, and generated in areas of high stress distributions. Previous studies have utilized numerical methods and finite element methods to predict bone structure …

Control Of Longitudinal Pitch Rate As Aircraft Center Of Gravity Changes, John Andres Cadwell Jr.

Master's Theses

In order for an aircraft to remain in stable flight, the center of gravity (CG) of an aircraft must be located in front of the center of lift (CL). As the center of gravity moves rearward, pitch stability decreases and the sensitivity to control input increases. This increase in sensitivity is known as pitch gain variance. Minimizing the pitch gain variance results in an aircraft with consistent handling characteristics across a broad range of center of gravity locations.

This thesis focuses on the development and testing of an open loop computer simulation model and a closed loop control system to …

Static And Fatigue Failure Response Of Woven Carbon Fiber Specimens With Double Edge Notches, Ahmad J. Amini

Master's Theses

Carbon fiber composites are continually seeing increased use in aerospace applications. It is necessary to understand their failure modes in order to properly design and perform analysis on structures constructed primarily from them. This thesis studies woven carbon fiber composites with and without double-edge notches in a series of static and fatigue tests performed on an Instron 8801 servo-hydraulic testing system.

Specimens were constructed of Advanced Composites Group product # LTM45EL woven carbon fiber pre-preg/epoxy and were cut to approximately 9-inch in length and 1-inch in width. Notches were cut into some of the specimens using a slitting saw blade …

Effects Of Cloud-Induced Photovoltaic Power Transients On Power System Protection, Joel A. Nelson

Master's Theses

As the world strives towards finding alternative sources of power generation, photovoltaic generation has become an increasingly prevalent alternative energy source on power systems world-wide. This paper studies the effects that incorporating photovoltaic generation has on the existing power systems and their power system protection schemes. Along with the addition of this emerging alternative energy source comes the volatility of PV power generation as cloud-cover produces erratic variations in solar irradiance and PV power production. Such variations in PV power may lead to unfavorable operating conditions and power system failures. The issues addressed in this paper include a study of …

Artificial Skin Tactile Sensor For Prosthetic And Robotic Applications, Ross James Miller

Master's Theses

To solve the problem of limited tactile sensing in humanoid robotics as well as provide for future planned mechanical prostheses, an innovative tactile sensor system was created and embedded into two realistic-looking artificial skin gloves. These artificial skin tactile sensors used small piezoelectric ceramic disks to measure applied force at multiple points on each glove. The gloves were created using silicone rubber to simulate both the texture and look of human skin, while maintaining both flexibility and durability. The sensor outputs were buffered by high-impedance voltage-following operational amplifiers, and then read sequentially using a multiplexing scheme by a microcontroller. Sensor …

The Effectiveness Of Damage Arrestment Devices In Delaying Fastener-Hole Interaction Failures In Carbon Fiber Polyurethane Foam Composite Sandwich Panels Subjected To Static And Dynamic Loading Under Increased Temperatures, Dominic E. Surano

Master's Theses

A study was conducted to investigate simple, cost-effective manufacturing techniques to delay skin-core delamination, micro-buckling and bearing stress failures resulting from fastener-hole interactions. Composite sandwich panels, with and without damage arrestment devices (DADs), were subjected to monotonic compression at a rate of 5mm per second, and compression-compression fatigue at 50% yield at an amplitude of 65%, under temperatures of 75, 100, 125, 150, 175, and 200 °F.

The sandwiches tested were composed of two-layer cross-weave carbon fiber facesheets, a polyurethane foam core, and an epoxy film adhesive to join the two materials. The most successful method to delay the aforementioned …

Assessment Of Morphology And Hemodynamics In Normal And Remodeled Microvasculature With Parameter Sensitivity Analysis, Shilpi Ghosh

Master's Theses

The goal of this study was to compare the morphological and hemodynamic characteristics of normal and remodeled vascular networks in the mouse gracilis muscle. To this end, previously developed models to assess flows and vascular branching were used to assess the normal and remodeled microcirculatory networks. The analysis revealed that the average individual vessel flow rates for vessels of similar caliber and total volumetric flow rates in the networks do not change for vessels of the same caliber after remodeling. Connectivity changes and average diameters primarily change in the larger arterioles after remodeling. A few correlations could be made between …

Anaerobic Co-Digestion Of Wastewater Treatment Pond Algae With Wastewater Sludge, Daniel Eric Heimel

Master's Theses

Microalgae harvested from wastewater treatment ponds can be anaerobically digested to produce biogas, a renewable fuel resource. However, past experiments have shown some limitations of algae digestion. Algal cell walls are thought to be resistant to digestion, and the high protein content of algae can lead to ammonia toxicity in digesters. Co-digestion of algae with substrates containing higher C:N ratios (e.g., waste paper) can be used to maintain non-inhibitory ammonia concentrations and increase methane production. However, high carbon waste co-substrates have become costly or are not readily available in many communities. Although domestic wastewater sludge has only a marginally higher …

Development Of Cubesat Vibration Testing Capabilities For The Naval Postgraduate School And Cal Poly San Luis Obispo, Marissa Brummitt

Master's Theses

The Naval Postgraduate School is currently developing their first CubeSat, the Solar Cell Array Tester CubeSat, or NPS-SCAT. Launching a CubeSat, such as NPS-SCAT, requires environmental testing to ensure not only the success of the mission, but also the safety of other CubeSats housed in the same deployer. This thesis will address the development of CubeSat vibration testing methodology at NPS, including subsystem testing, engineering unit qualification, and flight unit testing. In addition, the new Cal Poly CubeSat Test POD Mk III will be introduced and evaluated based upon comparison with the Poly Picosatellite Orbital Deployer (P-POD). Using examples from …

A New Ac-Dc Converter Using Bridgeless Sepic, M. R. Sahid, A. H. M. Yatim, Taufik

Electrical Engineering

A new bridgeless power factor correction circuit (PFC) based on single ended primary inductance converter (SEPIC) is proposed. The number of component conducted at each subinterval mode is reduced compared to the existing topologies. Analysis of the converter operated in discontinuous-conduction mode (DCM) is discussed. Experimental circuit for the proposed converter is developed with universal input voltage capability for 50V DC output voltage connected to 100W load. The simulation and experimental results are presented to show the performances of the proposed circuit.

Improved Rf Power Extraction From 1.55Μm Ge/Si N-I-P Photodiodes With Load Impedance Optimization, Andrew L. Huard, Molly Piels, Anand Ramaswamy, John E. Bowers, Dennis J. Derickson

Electrical Engineering

The RF output power of Ge/Si n-i-p waveguide photodetectors is improved by increasing the load impedance. The maximum extracted RF power at 3GHz is 17.13dBm with a compression current of 42mA using a 100Ὠ load.

A New Multiphase Multi-Interleaving Buck Converter With Bypass Lc, Taufik, Randyco Prasetyo, Dale Dolan, Dodi Garinto

Electrical Engineering

As the number of transistors in microprocessors increases, their power demand increases accordingly. This poses design challenges for their power supply module called VRM (Voltage Regulator Module) especially when operated at sub voltage range. This paper presents the design of a new multiphase multi-interleaving topology that addresses these challenges. A lab scaled hardware prototype of the new topology shows improved load regulation, output voltage ripple and dynamic response time compared to a commercially available power supply module.

Characterization Of Inconel 718: Using The Gleeble And Varestraint Testing Methods To Determine The Weldability Of Inconel 718, Nathaniel Oscar Knock

Master's Theses

Nickel based superalloys were developed to withstand the severe thermal and mechanical environment associated with rocket propulsion systems and jet engines. In many alloy systems the strength of a component rapidly deteriorates as the operating temperature increases. Nickel based superalloys, however, retain strength over a range of temperatures which includes the operating range for many propulsion systems. This improved performance is accomplished by a combination of solid-solution strengthening, precipitation strengthening and grain-boundary strengthening. Furthermore, super-alloy systems are designed for ease of fabrication, to include machining, welding and heat treating. Inconel 718 was developed to overcome problems with post-weld cracking that …

Application Of Differential Evolution To Determine The Hepwm Angles Of A Three Phase Voltage Source Inverter, N Bahari, Z. Salam, Taufik

Electrical Engineering

This paper presents an efficient Differential Evolution (DE) based solution for harmonic elimination pulse-width modulation (HEPWM). The aim is to solve for the set of transcendental equations that determine the switching angles of the HEPWM waveform. The objective function of the DE is designed to minimize (to near zero) the selected harmonics and at the same time allows for the fundamental component of the output voltage to be controlled independently. To verify the method, simulation is carried out using MATLAB simulink. The computed switching angles are applied to a three phase voltage source inverter. Typical results are shown and discussed.

An Investigation Of The Influence Of Diaphragm Flexibility On Building Design Through A Comparison Of Forced Vibration Testing And Computational Analysis, Blake Alan Roskelley

Master's Theses

An assessment of the validity of idealizing a concrete diaphragm as rigid was performed through the modal analysis of three existing buildings. Modal analysis was performed both by physical experimentation and computational analysis. Experimental determination of the mode shapes shows that two of the three buildings’ diaphragms exhibited flexible behavior. The experimental results were compared to computational analysis results and were shown to be similar, confirming that that the two building diaphragms are not rigid. As a standard, diaphragms with aspect ratios less than three are permitted to be idealized as rigid per ASCE 7-05. To determine the effect of …

Design And Implementation Of User Level Socket Application Programming Interface With Socket Splitting And Mediation, Scott Walter Holzer

Master's Theses

Over the past few decades, the size and scope of the Internet has grown exponentially. In order to maintain support for legacy clients, new applications and services have been limited by dependence on traditional sockets and TCP, which provide no support for modifying endpoints after connection setup. This forces applications to implement their own logic to reroute communications to take advantage of composable services or handle failover. Some solutions have added socket operations that allow for endpoints to be redirected on the fly, but these have been limited in scope to handling failover and load balancing.

We present two new …

Fuzzy Logic Control Of An Inverted Pendulum Robot, Kyle Reid

Electrical Engineering

The inverted pendulum is a classical problem in controls.  The inherit instabilities in the setup make it a natural target for a control system.  Over the years it has been the benchmark for testing new and innovative control theories such as Fuzzy Logic.  During the course of this project a software fuzzy logic controller was implemented using a PIC microcontroller.  At the conclusion of the experiment an interesting realization was made about the nature of Fuzzy Logic and its applicability in the world of controls.

A Study Of Golf Club Head Kinematics Near Impact, Stephen James Murphy, David Wadsworth Lavelle, Kevin Philip Melancon

Mechanical Engineering

No abstract provided.

Can Spr Be Used To Interrogate The Double Layer Of Nacl, Brandon Kawula

Biomedical Engineering

Solutions of reagent grade salt .1, .01, .001, .0001, .00001M were run through a SPR to see if SPR had enough resolution to detect the formation of the electric double layer. We found that NaCl did in fact return a detectable signal. The signal shape seems to depend on concentration. While more study may need to be done to get definite information it looks like SPR can interrogate the double layer.

Designing A Photovoltaic System Hybrid For A Health Clinic In Camilo Ortega, Nicaragua, Jeremy Holliman

Electrical Engineering

As developing nations continue to foster the development of their technologies and economies, industrialized nations have taken an active approach in providing green and sustainable alternatives for them to consider. Non-profit organizations like Engineers Without Borders holds sustainable international development as paramount to all international projects that their student and professional chapters undertake. The Cal Poly Engineers Without Borders student chapter has implemented a variety of projects from slow sand filters to compressed earth blocks, and the Nicaragua team is in the process of designing a health clinic for the Camilo Ortega community. In order to power the health clinic, …

Evaluation Of The Stress-Energy Methodology To Predict Transmitted Shock Through Expanded Foam Cushions, J. Singh, L. Ignatova, E. Olsen, P. Singh

Industrial Technology and Packaging

Mechanical stresses experienced by packages in the distribution environment include shock and vibration amongst several others. The destructive effects of these hazards can typically be restricted by using cushioning materials to help protect fragile goods during distribution. ASTM D1596 is the conventional standard used to determine shock absorbing performance of a cushioning material for a given combination of static loading, thickness, and drop height. This industry-accepted standard, however, requires significant amounts of transmitted shock data and can be expensive with respect to costs associated with testing and materials amongst others. Alternate stress-energy-based methodologies, developed in the past decade, recommending a …

Modeling And Numerical Investigation Of Hot Gas Defrost On A Finned Tube Evaporator Using Computational Fluid Dynamics, Oai The Ha

Master's Theses

Defrosting in the refrigeration industry is used to remove the frost layer accumulated on the evaporators after a period of running time. It is one way to improve the energy efficiency of refrigeration systems. There are many studies about the defrosting process but none of them use computational fluid dynamics (CFD) simulation. The purpose of this thesis is (1) to develop a defrost model using the commercial CFD solver FLUENT to simulate numerically the melting of frost coupled with the heat and mass transfer taking place during defrosting, and (2) to investigate the thermal response of the evaporator and the …

Analysis And Simulations Of Z-Source Inverter Control Methods, B. Y. Husodo, M. Anwari, S. M. Ayob, Taufik

Electrical Engineering

In this paper, two different control methods for Z-source inverter are examined. The Simple Boost and the Maximum Boost control methods of the inverter are analyzed and compared each other using simulation with MATLAB/Simulink. The Simple Boost control with independence relation between modulation index and shoot-through duty ratio is also simulated and analyzed. The selection of high modulation index and shoot-through duty ratio can reduce the inverter’s dc link voltage overshoot and increasing power delivery capacity of the inverter.

Work In Progress - Role Of Faculty In Promoting Lifelong Learning: Initial Findings, John Chen, Susan M. Lord, Katharyn Nottis, Michael Prince, Candice Stefanou, Jonathon Stolk

Mechanical Engineering

Calls for educational reform emphasize the need for student-centered learning approaches that foster lifelong learning. To be a lifelong learner includes characteristics consistent with those of self-directed learners, such as being curious, motivated, reflective, analytical, persistent, flexible, and independent. Instructor support of students’ self-directed learning (SDL) development relies on understanding and balancing these factors in the classroom. Engineering educators play a critical role in influencing outcomes related to SDL through their design of courses that support students’ transitions from controlled to autonomous learning behaviors. This study will examine a variety of engineering courses and pedagogical approaches. Each will be characterized …

Modelling And Analysis Of Dynamic Capacity Complexity In Multi-Stage Production, Ahmed M. Deif, Hoda A. Elmaraghy

Industrial Technology and Packaging

The uncertainty associated with managing dynamic capacity problem is the main source of its complexity. This article presents a system dynamics approach to model and analyse operational complexity of dynamic capacity in multi-stage production. The unique feature of this approach is that it captures the stochastic nature of three main sources of complexity associated with dynamic capacity. These are the demand, internal manufacturing delay and capacity scalability delay. The developed model was demonstrated by an industrial case study of multi-stage printed circuit board assembly line. The analysis of simulation experiments showed that ignoring complexity sources can lead to wrong decisions …

Assessment Of State Recycling Regulations In The United States, Nazli Yesiller, James L. Hanson, Samuel A. Vigil

Civil and Environmental Engineering

This investigation was conducted to identify the current status of state recycling regulations in U.S. using an extensive survey. Questions were included regarding: baseline waste generation and recycling trends; recycling regulatory trends; quantitative thresholds; integration of science, engineering, and economic principles; material properties; and legislative status of regulations. The majority of the surveyed states had regulations for recycling activities, which were less strict than solid waste regulations, and required permits for operation of recycling facilities. A low percentage of the states regulated generators, transporters, and handlers and a high percentage regulated recyclers. In general, transfer stations and recycling centers were …

Modernización De Proyectos De Riego, Charles M. Burt

BioResource and Agricultural Engineering

Un diseño moderno es el resultado de un proceso de reflexión, el cual selecciona la configuración y componentes físicas considerando un programa de operación bien definido y realista basado en el concepto de servicio.

Medición De Gasto En Canales De Riego Y...Otras Cosas, Charles M. Burt

BioResource and Agricultural Engineering

Nuestra opción preferida para Eiqupos de “flujo crítico ” (vertedor or aforador) son Aforadores Replogle (Garganta Larga)