Engineering Commons^™

Development Of A Finite Element Method For Light Activated Polymers, Craig Hamel

Theses

Traditional Shape Memory Polymers (SMPs) belong to a class of smart materials which have shown promise for a wide range of applications. They are characterized by their ability to maintain a temporary deformed shape and return to an original parent permanent shape. The first SMPs developed responded to changes in temperature by exploiting the difference in modulus and chain mobility through the glass transition temperature. However, in recent years, new SMPs have been developed that respond to other stimuli besides temperature; these can include electricity, magnetism, changes in chemical concentration, and even light.

In this thesis, we consider the photo-mechanical …

Simulation Of Electronic And Optical Properties Of Graphene, Biao Leng

Theses

Graphene is a recently discovered two-dimensional crystal. Due to its excellent electronic properties, transport properties, optical properties, and many other features, it has tremendous potential for applications in many areas. This thesis discusses the structure and properties of graphene using several different models of graphene and carries out detailed theoretical studies and calculations of its electronic and optical properties. Using two modules of Materials Studio, CASTAP and Doml3, four graphene models have been constructed. Their electronic and optical properties have also been calculated via these two modules. By comparing the results of calculations with experimental results and the literature, the …

Differentiation Of Mouse Embryonic Stem Cells Into Insulin-Producing Cells: Optimization To Enhance The Overall Differentiation Efficiency, Xiaotang Ma

Theses

Embryonic stem cells have the potential to differentiate into multiple cell types including insulin-producing cells (IPCs), which is becoming one of the promising cell sources for treating type 1 diabetes mellitus. However, in order to achieve functional stem cell-derived cells, it is important to generate more mature IPCs and to keep long-term viability post differentiation process. In this study, we varied several factors including different embryonic body culture conditions, digested cells seeding density and various coatings required for differentiation to optimize a previously established protocol to enhance the overall differentiation efficiency. Moreover, a three-dimensional in vitro collagen tissue culture system …

Thermal Properties Of Graphene, Vishal Vijay Nakhate

Theses

The two-dimensional (2D) monolayer structure of carbon atoms were initially considered as unstable. The 2D materials have recently been discovered and many researchers have started analyzing these materials. Graphene, a two-dimensional allotrope of graphite with sp2 bonded carbon atoms, is arranged in honeycomb structure. Graphene has excellent thermal conductivity and can be considered as a potential material for applications in the electronics industry where heating of materials is a serious concern.

In this study, thermal properties of p and n doped graphene nanosheets and nanoribbons are studied as function of percentage composition of the dopants and the direction of dissipation …

Tendon Reflex Protocol For Exploring The Mechanisms Associated With Whole Body Vibration, Ikechukwu Okeke

Theses

Whole body vibration (WBV) machines have in recent years been widely used as rehabilitation equipment. Whole body vibration has been shown to have positive effects on muscle response. Cerebral palsy (CP) is a neurodevelopmental condition that includes a group of non-progressive, but often changing, motor impairment syndromes arising in the early stages of human development. The aim of this project was to design a protocol and related instruments to assess the tendon reflex in response to WBV. Both a press pedal used for measuring the force exerted by the foot and a hammer used for measuring the stimulating force were …

Behavior Of Deformed Dermal Fibroblasts Seeded On A Silicon Membrane Under High Levels Of Strain, Laura Osorno

Theses

The main objective of this thesis is to understand, from a molecular perspective, the morphological and functional abnormalities of human dermal fibroblasts as a response to deformation produced by a normal force that can lead to the potential formation of stretch marks in pregnant women, adolescents, and people with Cushing's syndrome. The main function of dermal fibroblasts is to produce the essential fibrous components of the extracellular matrix (ECM) of the skin.

In order to study the mechanism of stretch mark formation, neonatal human dermal fibroblasts were seeded on a silicon membrane for controlled deformation. Upon reaching a confluence of …

Processing And Characterization Of Graphene And Graphene On Silicon, Cheng Peng

Theses

Graphene has become a promising material for applications in many areas including electronic devices, batteries and space crafts. Although it has a bright future, the commercial production of graphene has not yet been realized. In this thesis, an overview of the properties and applications of graphene is presented. The early research of preparing graphene and its composites is summarized, which gives the basis to synthesize graphene and improve the process. In this study, graphene oxide (GO) and graphene have been successfully made using graphite; graphene layer has been coated on the surface of a silicon wafer. The resulting specimens are …

Design, Construction And Characterization Ofa Magnetic Augmented Rotation System (Mars) Based Wind Turbine, Da Li

Theses

Magnetic Augmented Rotation System (MARS) works by magnetic field coupling, to transfer torque from the driver to the rotor without contact. This characteristic has significant applications to the wind turbine but research in combination of MARS and wind turbine has not been done in the literature. In this thesis, a small-scale wind turbine is designed, built and characterized in a prototype wind tunnel. The test results are analyzed and computer-aided software simulation is used as an auxiliary method to understand the mechanism of MARS. The power coefficient of this new wind turbine is estimated to be about 40%. The “gear …

Optical Properties Of Black Silicon - An Analysis, Suramya Sekhri

Theses

Silicon is the preeminent solar cell material of the day because it is the first semiconductor that was learned to commercialize and continues to be the principal semiconducting material used in photovoltaic technology for the manufacture of solar cells. Silicon, an indirect band gap semiconducting material, has a reflectance of about 30% in the visible range of wavelengths. Standard Silicon solar cells are not entirely useful in the infrared spectrum region. In order to enhance the performance of Silicon solar cells, reflectance losses must be minimized and absorption must be maximized. In the solar cell industry, anti-reflection (AR) coating is …

An Extended Duration Operation For Solid Hollow Fiber Cooling Crystallization Method, Chi Jin

Theses

As recently demonstrated by Chen et al. [1], the solid hollow fiber cooling crystallization method to achieve continuous polymer coating/encapsulation of submicrometer particles, has advantages of no problem with high pressure, easy scale-up and production of free-flowing coated particles. There is a concern whether this crystallization method can be applied for an extended duration coating process; it was not investigated in the previous study. Therefore, in order to examine this problem, in this work, the duration of the whole crystallization coating process has been greatly extended from 5 min to 60 min and 120 min. For the purpose of being …

Significant Degradability Enhancement In Multilayer Coating Of Polycaprolactone-Bioactive Glass/Gelatin-Bioactive Glass On Magnesium Scaffold For Tissue Engineering Applications, Mostafa Yazdimamaghani, Mehdi Razavi, Daryoosh Vashaee, Venkata Raveendra Pothineni, Jayakumar Rajadas, Lobat Tayebi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Magnesium (Mg) is a promising candidate to be used in medical products especially as bone tissue engineering scaffolds. The main challenge for using Mg in biomedical applications is its high degradation rate in the body. For this reason, in this study, a multilayer polymeric layer composed of polycaprolactone (PCL) and gelatin (Gel) reinforced with bioactive glass (BaG) particles has been applied on the surface of Mg scaffolds. The materials characteristics of uncoated Mg scaffold, Mg scaffold coated only with PCL-BaG and Mg scaffold coated with PCL-BaG and Gel-BaG have been analyzed and compared in detail. Scanning electron microscope (SEM) equipped …

Capacitance Measurements Of Defects In Solar Cells: Checking The Model Assumptions, Justin R. Davis

Senior Theses

Capacitance measurements of solar cells are sensitive to minute changes in charge in the material. For that reason, capacitance is used in several methods to electrically characterize defects in the solar cell. Standard interpretations of capacitance rely on many assumptions, which, if wrong can skew the results. We explore possible alternative explanations for capacitance transitions, such as a non-ideal back contact and series resistance. Using Drive Level Capacitance Profiling measurements, a capacitance step is linked to a defect between the energy bands of a solar cell.

Thermally/Mechanically Responsive Polymeric Composites With Shape Memory/Self-Healing Properties, Hossein Birjandi Nejad

Dissertations - ALL

Smart materials with the ability to respond to external stimulus have attracted tremendous attention in both academic institutions and industry. Such unique aspect of these materials make them great candidates to address current challenges in the world of Materials Science including those that no human intervention is a necessity. The objective of this dissertation is to employ different techniques to develop novel thermally and mechanically responsive polymeric composites for several industrial applications.

In Chapter 2, the curing kinetics and polymerization induced phase separation (PIPS) of an epoxy matrix with and without a semicrystalline thermoplastic was investigated. Same PIPS technique studied …

Climate Change Assessment In Columbia River Basin (Crb) Using Copula Based On Coupling Of Temperature And Precipitation, Yueyue Qin

Dissertations and Theses

The multi downscaled-scenario products allow us to better assess the uncertainty of the variations of precipitation and temperature in the current and future periods. Joint Probability distribution functions (PDFs), of both the climatic variables, might help better understand the interdependence of the two, and thus in-turn help in accessing the future with confidence. In the present study, we have used multi-modelled statistically downscaled ensemble of precipitation and temperature variables. The dataset used is multi-model ensemble of 10 Global Climate Models (GCMs) downscaled product from CMIP5 daily dataset, using the Bias Correction and Spatial Downscaling (BCSD) technique, generated at Portland State …

Reversible Circuits Synthesis Based On Exor-Sum Of Products Of Exor-Sums, Linh Hoang Tran

Dissertations and Theses

Power dissipation in modern technologies is an important matter and overheating is a severe concern for both manufacturer (impossibility of introducing new and smaller scale technologies and limited temperature range for operating the product) and customer (power supply, which is especially important for mobile systems). One of the main profits that reversible circuit carries is theoretically the zero power dissipation in the sense that it is independent of underlying technology; irreversibility means heat generation. In the other words, reversible circuits may offer a feasible solution in the future that will aid certain reduction of the power loss.

Reversible circuits are …

A Study Of Mixing In A Magnetohydrodynamic (Mhd) Microfluidic Cell By Numerical Simulations, Fangping Yuan, Kakkattukuzhy M. Isaac

Collaborative Research: Actively Controllable Microfluidics with Film-Confined Redox-Magnetohydrodynamics -- Video and Data

No abstract provided.

Santa Clara Creek Restoration, Scott Cameron

Civil, Environmental and Sustainable Engineering Senior Theses

The Santa Clara River Valley is an area that has traditionally had a considerably high water table and that remains relatively true today as a result of a local adoption of imported surface water to meet most needs. Historically, the result of this high water table was a network of meandering waterways throughout the valley, several of which came extremely close to our own Santa Clara University. Despite this, there are no natural surface water systems that exist in this location today. In 1851, a Santa Clara county surveyor report showed one creek in particular that flowed nearly to the …

Power Maximization Of A Three-Phase Hydrokinetic Turbine, Matthew Carleson

Senior Theses

As Earth`s expendable resources dwindle, the need for alternative, renewable energy sources grows. Out of this need, an old favorite source is rising in popularity: small water turbines. Water-driven turbines first began as a means for turning mills and eventually evolved into massive dams that can power whole regions. This project focused on the construction of, and testing the properties of, a small pico-hydro power turbine. By using compressed air to drive the turbine, a representation of the peak power output was measured, serving as a basis for determining the value of pico-power systems in regards to the world`s current …

Best Practices For Designing An Undergraduate Engineering Curriculum, Subrata Das, Komal K. Das, Krishna Singh

Journal of Research Initiatives

This article offer examples of best practices for planning instructional learning within the naturalistic setting and based on real learning experiences. The inquiry, based on practices and strategies proven successful in an undergraduate engineering class is the focus of this best practices article. This article is also a useful guide for administrators, practitioners, and undergraduate educators who make decisions on instructional delivery and scholarship. The instructional activities offer core instruction and curriculum modules on best practices for effective college instruction.

Effects Of Individualized Centrifugation Training On Orthostatic Tolerance In Men And Women, Nandu Goswami, Joyce Evans, Stefan Schneider, Melanie Von Der Wiesche, Edwin Mulder, Andreas Rössler, Helmut Hinghofer-Szalkay, Andrew P. Blaber

Biomedical Engineering Faculty Publications

AIMS: Exposure to artificial gravity (AG) at different G loads and durations on human centrifuges has been shown to improve orthostatic tolerance in men. However, the effects on women and of an individual-specific AG training protocol on tolerance are not known.

METHODS: We examined the effects of 90 minutes of AG vs. 90 minutes of supine rest on the orthostatic tolerance limit (OTL), using head up tilt and lower body negative pressure until presyncope of 7 men and 5 women. Subjects were placed in the centrifuge nacelle while instrumented and after one-hour they underwent either: 1) AG exposure …

Fast Semivariogram Computation Using Fpga Architectures, Yamuna Sri Lagadapati

Electrical Engineering Theses

The semivariogram is a statistical measure of the spatial distribution of data, and is based on Markov Random Fields (MRFs). Semivariogram analysis is a computationally intensive algorithm that has typically seen applications in the geosciences and remote sensing areas. Recently, applications in the area of medical imaging have been investigated, resulting in the need for efficient real time implementation of the algorithm. A semi-variance, Î(h), is defined as the half of the expected squared differences of pixel values between any two data locations with a lag distance of h. Due to the need to examine each pair of pixels in …

Potable Water Production From Third River In Nasiriyah City, Ahmed Faiq Al-Alawy, Jaafar Jabbar Madlool, Ali Ibrahim Neamah

The Hilltop Review

The present work aims to study the efficiency of coagulation/ flocculation as pretreatment then using membrane technology, microfiltration (MF) and Reverse Osmosis (RO), for treatment of water of Third River in Nasiriyah city in Iraq. Effects of operating parameters such as coagulant dosage, speed and time of slow mixing step and settling time in the pretreatment stage were studied. Also feed turbidity and TSS in the MF stage were studied. Also feed concentration, temperature and operating time, in the RO stage were studied. The results showed that the optimum dosage for alum was 40, 45 and 50 ppm. While, for …

Predictive Modeling Of Oxygen Transmission Through Micro-Perforations For Packaging Applications, Ayman Abdellatief, Bruce A. Welt, Jason Butler, Eric Mclamore, Arthur Teixeira, Sanjay Shukla

Journal of Applied Packaging Research

Methods for creating precise perforations in respiring produce packaging are being increasingly adopted. Knowledge of oxygen transfer through perforated packaging and oxygen distribution in packages is necessary for successful packaging design of fresh produce. An approach to modeling perforated packaging performance was developed using a cylindrical chamber with precision perforations using Fick’s second law. The model was simulated using two techniques including Finite Element Method (FEM) using commercially available software and Finite Volume Method (FVM) through programming. Perforations were approximated as a source term in the second method. Both simulation techniques showed trends similar to experimental data.

Interview With Bill Baney, Rca Heritage Program

RCA Oral History Transcripts

Interview with Bil Baney for the RCA Heritage Program Oral History grant.

Interview With Ted And Rita Markiewitz, Rca Heritage Program

RCA Oral History Transcripts

Interview with Ted and Rita Markiewitz for the RCA Heritage Program Oral History grant.

Interview With Hal Pschunder, Rca Heritage Program

RCA Oral History Transcripts

Interview with Hal Pschunder for the RCA Heritage Program Oral History grant.

Branch Cutter Adapter For Electric Impact Gun, Cullen Hubbard

Mechanical Engineering and Technology Senior Projects

There are many homeowners that would like to maintain the trees around their homes but cannot do so. The drive of this project was to develop a 0g mechanism which would provide a senior citizen or an individual with limited upper body strength, with the ability to cut through branches that would otherwise pose challenging. The design would allow the end user to cut a branch by simply pulling a trigger. A branch cutting attachment was designed to attach to the front of a DeWALT cordless impact gun. This attachment will convert the rotational torque and motion from the impact …

Collapsible Wheelchair Wheel Design, Joseph Fischer

Mechanical Engineering and Technology Senior Projects

Portability, convenience, and efficiency are becoming more and more prevalent as technology increases. This is also true with wheelchairs; Wheelchairs are being designed to fold and collapse smaller and smaller with every iteration but there is one parameter that remains constant, the wheel. No matter how small the wheelchair frame folds it is always limited by its’ wheel’s diameter. This project aims to create a collapsible wheel design to accompany a foldable wheelchair in order to make it more portable and storable. Since the diameter of the wheel is the limiting factor in a foldable wheelchair, the relatively small width …

Custom Glasses Cases, Nikolas Ivan Klukas

Mechanical Engineering and Technology Senior Projects

The modern market is centralized around technological advances that improve and better everyday life. With approximately 150 million Americans that use corrective eye-ware on a daily basis, the need for improved technology in glasses cases is inevitable. Current glasses cases work to either protect the glasses and are big and bulky, or are made smaller to be more easily transported. The concept is to take any pair of glasses and make a custom case for them. The programs being utilized to complete the project are solidworks and excel. The process is started by making a base layout of the glasses …

Composite Brake Rotor Assembly By Utilizing Replaceable Friction Surfaces, John Evert

Mechanical Engineering and Technology Senior Projects

This project investigated a proof of concept design involving a rotor fabricated from aluminum with replaceable friction surfaces with greater or equal performance characteristics in order to reduce cost and maintenance. The replaceable friction surfaces provide a means to mitigate cost to the end user. The structure is constrained by the dimensions, 11.75” diameter and 1.25” width and serves as a direct replacement rotor for a circle track racecar. Analyses provide a direct comparison in static mass, moments of inertia, and forced convection thermal calculations in order to determine if the concept was viable. Requirements for a successful design were …