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Linfield University

Theses/Dissertations

Articles 31 - 46 of 46

Full-Text Articles in Physical Sciences and Mathematics

Protein Folding & Self-Organized Criticality, Arun Bajracharya May 2016

Protein Folding & Self-Organized Criticality, Arun Bajracharya

Senior Theses

Proteins are known to fold into tertiary structures that determine their functionality in living organisms. However, the complex dynamics of protein folding and the way they consistently fold into the same structures is unknown. Experimental studies of the folding process are difficult as proteins are made of more than one subunit and possess a high degree of conformational flexibility. Theoretically, self-organized criticality (SOC) has provided a framework for understanding complex systems in various scientific disciplines through scale invariance and the associated "fractal" power law behavior. Evidence of this criticality phenomena has been found in neural systems, cell cultures, and anesthetized …

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Capacitance Measurements Of Defects In Solar Cells: Checking The Model Assumptions, Justin R. Davis May 2015

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.

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Power Maximization Of A Three-Phase Hydrokinetic Turbine, Matthew Carleson May 2015

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 …

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Effect Of Seam-Height On Curveballs, Joseph S. Carroll May 2015

Effect Of Seam-Height On Curveballs, Joseph S. Carroll

Senior Theses

The difference in seam-height between raised and flat-seam baseballs causes them to react differently when thrown by a pitcher. Altering the seam-height on the ball changes the amount of drag force on it as it travels through the air. The goal of this experiment is to measure the difference in vertical deflection between the two types of balls when pitched with curveball topspin. It was discovered that the baseball with raised-seams experiences more vertical deflection than the flat-seam ball.

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Measuring Charge Carrier Mobility In Graphene, Christina A. Harmon May 2015

Measuring Charge Carrier Mobility In Graphene, Christina A. Harmon

Senior Theses

This research reports measurements of electron mobility in Graphene Field Effect Transistors (GFET), gated with liquid. Mobility is a quantity describing how easily charge carriers move through a material. GFET biosensors have the greatest sensitivity when the mobility is high; therefore, increasing mobility should improve sensitivity of these and similar devices. An optimal method was established for preparing samples and taking measurements of a liquid-gate device. Sheet conductivity was measured using van der Pauw geometry and carrier density was determined from measurements of the liquid-gate capacitance. It is shown that mobility improves after the graphene surface is cleaned by an …

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Measuring Strain In Trusses, Spencer Metzsch May 2015

Measuring Strain In Trusses, Spencer Metzsch

Senior Theses

Strain is an important quantity in engineering design and materials science that relates the deformation of a material to its original length, through a percentage. Different materials exhibit particular qualities under loading, for example the amount of strain due to a certain magnitude of force, or the amount of strain that can be borne before failure. This experiment aims to compare the relative strengths of three common truss configurations by measuring the strain in their members under loading. The Queen’s post truss was found to be the best at minimizing strain under similar loading conditions.

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Does Protein Folding Exhibit Self-Organized Criticality?, Addison Wisthoff May 2014

Does Protein Folding Exhibit Self-Organized Criticality?, Addison Wisthoff

Senior Theses

Proteins are known to fold into tertiary structures that determine their functionality in living organisms. By understanding the general features of this folding process, that are independent of specific proteins, folding can be better understood. Self-organized critical systems exhibit behavior that scales with system size. In this project, I wrote a simulation of a simplistic three-dimensional cubic lattice protein model. The model consisted of only two different types of amino acids, one being hydrophobic and the other hydrophilic, known as the HP model. To identify self-organized criticality in proteins, there must be clear signs of power law behavior in the …

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Optimization Of Chemical Vapor Deposition Grown Graphene, Andrew Tan May 2014

Optimization Of Chemical Vapor Deposition Grown Graphene, Andrew Tan

Senior Theses

Graphene can be used as the active film in a gas sensor. To provide the best possible electrical properties, it is important that graphene films be single-layered and single-crystalline. A low vacuum chemical vapor deposition (CVD) chamber was constructed to grow graphene with these properties. The effect of growth parameters, such as annealing times and methane partial pressure, on the quality of graphene was investigated. Raman spectra of graphene were used to quantify the characteristics of the synthesized graphene. Graphene synthesized through CVD has two major peaks, the G (~1570cm-1) and the 2D peak (~2700 cm-1). …

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Line Defects In Single Crystal Ceb6 Electron Emitters, Nicholas Fairhart May 2014

Line Defects In Single Crystal Ceb6 Electron Emitters, Nicholas Fairhart

Senior Theses

Electron emitters are essential components in many microscopy systems, including scanning electron microscopes, transmission electron microscopes, and scanning Auger microprobes. One feature of good electron emitter materials is a low surface work function. CeB6 is one such material. Line defects seen in CeB6 affect the work function of the emitting surface, causing the emitted electrons to have a wider spread of energies. This causes chromatic aberration, reducing the resolution of the microscope systems. The purpose of this research is to find the source of these line defects in the CeB6 emitter fabrication process. It was suspected that …

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Comparison Of The Performance Of Metal And Wood Baseball Bats, Kramer Lindell May 2014

Comparison Of The Performance Of Metal And Wood Baseball Bats, Kramer Lindell

Senior Theses

In baseball, bats made of metal are designed to perform like bats made of wood. To test how similarly they actually perform, both types of bats were used by hitters in a batting cage off of a pitching machine. The pitching machine's velocity could be adjusted as needed. A radar gun was used to measure the velocity of a batted baseball. The exiting velocities of balls hit with metal and wood bats were compared. The natural bending modes were also analyzed to compare the size of each sweet spot. It was discovered that when missing the sweet spot the bats …

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Constructing And Testing A Permanent-Magnet Railgun, Yangfan Wu May 2013

Constructing And Testing A Permanent-Magnet Railgun, Yangfan Wu

Senior Theses

A modified magnetic railgun has been built and investigated. Permanent magnets were used to supply the magnetic field and a car battery was used to provide the current. The projectile has been successfully shot out. An alternative way to create a magnetic field is running a large current through the rails. Preliminary calculations revealed that the current will need to be enormous in order to provide a satisfactory magnetic field. For such a large current a huge capacitor pool would be necessary. Strong permanent magnets are available and allow us to bypass the difficulties of simply using the current in …

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Investigating The Benefit Of Using Magnetorheological Fluids In A Shock Absorber, Chao Guo May 2013

Investigating The Benefit Of Using Magnetorheological Fluids In A Shock Absorber, Chao Guo

Senior Theses

The beneficial properties of magnetorheological fluids are applied in the design and testing of a prototype suspension system. Because viscosity of these fluids increased tremendously under the influence of a magnetic field, a suspension shock absorber containing magnetorheological fluids fluid is proposed. The shock system tested displayed resistance to motion with respect to the magnetic field strength.

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Correlating Fiber Quality Assurance Tests For The Nova Far Detector Modules, Amanda K. Bowers Jan 2013

Correlating Fiber Quality Assurance Tests For The Nova Far Detector Modules, Amanda K. Bowers

Senior Theses

In an effort to better understand the most fundamental units of matter, physicists are drawn to study the elusive neutrino. Measuring various parameters of neutrinos resulting from their oscillations between three different flavor states can lead to an explanation for the asymmetry between matter and antimatter in the universe. Because they are massless and weakly interacting, detecting these leptons has been a challenging feat. However, large-scale collaborations, such as NOvA, are now able to build detectors that capture information about a neutrino's interaction with atomic matter. During their propagation through space, neutrinos oscillate between various flavor states. Physicists are …

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Seismic Modeling With An Earthquake Shake Table, Jordan E. Barnes May 2012

Seismic Modeling With An Earthquake Shake Table, Jordan E. Barnes

Senior Theses

An earthquake shake table was constructed with three orthogonal directions of motion to simulate seismic waves. The peak amplitude and directions of motion are adjustable by the user. The table’s acceleration was measured at different amplitude settings for all three directions of motion, and that data was fit to the Peak Ground Acceleration (PGA) scale. This allows the table motion to be calibrated to the proper magnitude of an earthquake. An earthquake equivalent to 5.0 intensity on the PGA scale was achieved.

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Automatic Pet Door With Magnetic Field Activation, Alex J. Keith May 2012

Automatic Pet Door With Magnetic Field Activation, Alex J. Keith

Senior Theses

Pet doors were initially created for the consumer that has a pet but does not want to hassle with letting the pet in and out of the house or allowing them access to food and shelter. The market has been flooded with automatic pet doors that are activated by a magnetic field, radio frequency or other activation signal. These doors are designed to be installed in a door or door frame. These doors, however, are very expensive, made of low-cost materials, and are limited in the places that they can be installed. Also, because they commonly use elaborate motors built …

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A Maskless Photolithography Apparatus For The Microfabrication Of Electrical Leads, Kyel Lambert May 2012

A Maskless Photolithography Apparatus For The Microfabrication Of Electrical Leads, Kyel Lambert

Senior Theses

Graphene is a new and exciting, two-dimensional material. Particularly interesting are the electrical features of graphene. The small size of graphene used in this experiment (on the scale of microns) presents the need for small electrical leads. Photolithography can be used to make appropriately sized leads by depositing metal onto substrates in specific patterns. The technique uses light to transfer geometric patterns onto a light sensitive photoresist on the surface of a substrate. We have built a low cost, maskless photolithography apparatus assembled from a computer, a consumer grade projector, and a microscope. With multiple exposures, we can make features …

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