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Articles 1291 - 1320 of 2906

Full-Text Articles in Physical Sciences and Mathematics

Wireless Network Signal Analysis, Nathan P. Sharp, Dr. Mark E. Clement Jan 2014

Wireless Network Signal Analysis, Nathan P. Sharp, Dr. Mark E. Clement

Journal of Undergraduate Research

The process of measuring wireless signal strength for networks can be complex and subjective. There is no “tried and true” way of determining the best layout for a network, but with some fairly simple analysis, much can be done to improve the performance of the network. Empirical data shows how much different materials inhibit the signal (see Fig. 1-3 below). For example, in an office setting, determining if brick walls or cubical walls are more penetrable will be very useful when laying out a wireless network.

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Improved Hyperweb Search Efficiency Through Index Replication, Jared Holcomb, Dr. Scott Woodfield Jan 2014

Improved Hyperweb Search Efficiency Through Index Replication, Jared Holcomb, Dr. Scott Woodfield

Journal of Undergraduate Research

The hyperweb is a network based on a modified hypercube1 topology. It is used to create a peerto- peer network for a distributed database (such as a genealogical database.) Two major drawbacks that a peer-to-peer network suffers are a low reliability rate for individual nodes and a slower search speed as the system grows. Both of these problems can be addressed by replicating data across several nodes. First, any particular node has a relatively high probability of being down so a copy of the information a node contains is stored on several other nodes, thereby decreasing the total probability of …

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Interrelation Of Faultng, Karsting And Calcite Veining Near The South Flank Fault Zone Of The Uinta Mountains, Utah, Erin T. Duerichen, Dr. Jeffrey D. Keith Jan 2014

Interrelation Of Faultng, Karsting And Calcite Veining Near The South Flank Fault Zone Of The Uinta Mountains, Utah, Erin T. Duerichen, Dr. Jeffrey D. Keith

Journal of Undergraduate Research

In the Uinta Mountains, south of the South Flank Fault Zone, a thick sequence of Mississippian limestone is exposed. In the Blind Stream area, this limestone is transected by a series of north-south trending faults and fractures, with associated karsting (ie: large, collapsed cavities resulting from underground fluid migration, dissolving the carbonate rock) and calcite veining.

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Ä13c Isotope Analysis Of Pennsylvanian Carbonates In Arrow Canyon, Nevada, Julia Kahmann, Dr. Scott Ritter Jan 2014

Ä13c Isotope Analysis Of Pennsylvanian Carbonates In Arrow Canyon, Nevada, Julia Kahmann, Dr. Scott Ritter

Journal of Undergraduate Research

Carbonate rocks, when sampled and analyzed for their carbon isotopes, carry an isotopic signature that may be used as a correlation tool. When other tools do not suffice, or the present correlation needs to be enhanced, isotope analysis is an appropriate alternative. Arrow Canyon Nevada has extensive, continuous, cyclical packages of pristine limestone making the location a prime candidate for isotopic analysis. As an isotopic signal for the limestone cycles is established, the resulting isotope carbon curve may be used as a correlative to91 for other basins along the Pennsylvanian paleo-margin.

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Ratios Of Positive Definite Matrices, Dena Plant, Dr. Wayne Barrett Jan 2014

Ratios Of Positive Definite Matrices, Dena Plant, Dr. Wayne Barrett

Journal of Undergraduate Research

As our research began we focused on proving the hypothesis that for a 4 x 4 Positive Definite matrix A, the ratio

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Length Minimizing Network For N Points On The K-Torus, W. Lauritz Petersen, Dr. Denise Halverson Jan 2014

Length Minimizing Network For N Points On The K-Torus, W. Lauritz Petersen, Dr. Denise Halverson

Journal of Undergraduate Research

Our project consisted of several components with the end goal being: given n points on the ktorus (a donut with k number of holes), what would the shortest path network be to connect all the n points (network meaning a network of paths connecting each of the n-points).

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Optimal Energy Recovery In Finite Time For Linearly Dissipative Systems, Mark Meilstrup, Dr. Scott Glasgow Jan 2014

Optimal Energy Recovery In Finite Time For Linearly Dissipative Systems, Mark Meilstrup, Dr. Scott Glasgow

Journal of Undergraduate Research

Many physical processes involve the loss or dissipation of energy. For example, when pushing a box across the floor, some of the energy that is spent will be lost to frictional forces. Our research is concerned with the study of the energy which is lost, and also the energy which is recoverable, in the more complex setting of a linearly dissipative optical system. We consider some electromagnetic pulse, such as a laser beam, entering and interacting with an absorbing medium, such as glass or some gas. When the pulse exits the medium, some of the energy has been absorbed, and …

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Attachment Of Carbon Nanotubes To Atomic Force Microscopy Probe Tips With A Silicon Dioxide Thin-Film, Jed Whittaker, Dr. Robert Davis Jan 2014

Attachment Of Carbon Nanotubes To Atomic Force Microscopy Probe Tips With A Silicon Dioxide Thin-Film, Jed Whittaker, Dr. Robert Davis

Journal of Undergraduate Research

Atomic force microscopy (AFM) is a useful method for obtaining images of surfaces on the nanometer scale. It has been used to image surfaces in many environments, including in atmosphere, vacuum and fluids. The resolution of these images is subject to the size of the probe tip, which is pyramidal. It has been shown that the attachment of a carbon nanotube to an AFM probe tip increases resolution significantly, in both air and fluids1. The nanotubes have initially been attached by Van der Waals forces, individually, which are too weak for applications in fluids. For use in fluids, glues and …

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The Landau Damping Of A Manhole Cover, Landau Damping, Dr. Ross L. Spencer Jan 2014

The Landau Damping Of A Manhole Cover, Landau Damping, Dr. Ross L. Spencer

Journal of Undergraduate Research

Research groups at BYU and the University of California at San Diego (UCSD) are actively investigating the properties of pure-electron plasmas, which fall into the more general class of nonneutral plasmas. Electrons are excited and injected into a Malmberg-Penning trap where they form a cylindrical plasma. By perturbing the confining electrical potentials of the trap, various wave motions can be induced in the plasma. Some of these waves exhibit a phenomenon called Landau damping which transfers energy from the wave motion to the kinetic energy of the electrons, causing the wave to attenuate.

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Variability In Quasars, Catherine Morris, Dr. Eric Hintz Jan 2014

Variability In Quasars, Catherine Morris, Dr. Eric Hintz

Journal of Undergraduate Research

This project looked for variability in quasars 3C273 and Mark 509. Between May 2003 and July 2003 several nights of data were taken on these quasars. The project was also to see if “good” data on quasars could be obtained using the BYU 16” telescope, since not much research has been done on this topic at BYU. Over the summer data were also taken on various other quasars whose brightness ranged between 12 and 14.

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Using Maple For Calculations In The Clifford Algebra, Jared R. Stenson, Dr. Jean-Francois S. Van Huele Jan 2014

Using Maple For Calculations In The Clifford Algebra, Jared R. Stenson, Dr. Jean-Francois S. Van Huele

Journal of Undergraduate Research

In order to progress we are often forced to adopt certain conventions. Just over a century ago, several new scientific ideas were emerging which increased the need to revise our mathematical methods and adopt new standard approaches. The Clifford Algebra was one proposed formalism that met the needs of the day yet, for whatever reason, was left behind in favor of the conventional math we are familiar with. However, as we’ve delved deeper into modern science many are now looking back to this forgotten approach because of its conceptual ease and geometrical structure [1]. Understanding the nature, benefits, and limitations …

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A New Light At The End Of The Tunnel: Steps Toward A Nanocrystal Led, Jorj Ian Owen, Dr. Robert C. Davis Jan 2014

A New Light At The End Of The Tunnel: Steps Toward A Nanocrystal Led, Jorj Ian Owen, Dr. Robert C. Davis

Journal of Undergraduate Research

A light emitting diode (LED) is a semiconductor device that gives off light. An LED works by the combination of electrons and electron holes (a moving, positive charge caused by missing electrons). As the electron and electron hole combine, the electron joins the atom in an excited state (some greater than minimum energy level). The high-energy electron will then decay into a lower energy state by emitting a photon, a packet of energy. LEDs are useful for many reasons. For example, they are extremely efficient in converting electricity into light (unlike conventional tungsten bulbs), they do not get very hot, …

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Self-Referencing Interferometric Measurement Of Microradian Wedge Angles, Rebecca Olson, Dr. Scott D. Bergeson Jan 2014

Self-Referencing Interferometric Measurement Of Microradian Wedge Angles, Rebecca Olson, Dr. Scott D. Bergeson

Journal of Undergraduate Research

We developed a new interferometric method of measuring the wedge angles of beamsplitters and the deviation angles of penta prisms. This method could easily be extended to certify the angles on other optical pieces as well. We built the interferometer and analyzed the images using equipment that we already had in the lab, including a helium-neon laser, a CCD camera, framegrabbing computer hardware, and standard optical components.

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A High Power Green Laser, Bonnie J. Mclaughlin, Dr. Scott Bergeson Jan 2014

A High Power Green Laser, Bonnie J. Mclaughlin, Dr. Scott Bergeson

Journal of Undergraduate Research

High power green lasers are used extensively in laboratories for numerous applications. The cost for commercial green lasers is around $60,000. When I was searching for a research project for my senior thesis for my BS in Physics, Dr. Bergeson proposed I build a green laser for use in the experiments of the Atomic Molecular and Optical (AMO) research group. The laser was designed to pump other lasers with specific wavelengths for studying calcium at extremely low temperatures. We had also hoped to form a kit for building such lasers.

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Potential Inhibitors Of Hiv Integrase, Daniel A. Gubler, Dr. Matt A. Peterson Jan 2014

Potential Inhibitors Of Hiv Integrase, Daniel A. Gubler, Dr. Matt A. Peterson

Journal of Undergraduate Research

The purpose of my research is to synthesize a new class of enediynes that mimic linbenzoadenosine derivatives and have potential for inhibiting HIV integrase. This new class of enediynes is shown in Figure 1. Upon synthesis we will evaluate the biological activity of these compounds.

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Statistical Process Control Methods For Multiple Stream Processes: A Comparative Study, Jared Caleb Christensen, Dr. Scott D. Grimshaw Jan 2014

Statistical Process Control Methods For Multiple Stream Processes: A Comparative Study, Jared Caleb Christensen, Dr. Scott D. Grimshaw

Journal of Undergraduate Research

The Shewhart control chart is the most common statistical process control (SPC) tool used to determine stability. One fundamental assumption of the Shewhart chart is that the output comes from a single, continuous stream. This implies the monitoring of a single source of variation. Filling machines at many beverage plants violate this assumption because there are central filling units with multiple heads filling individual bottles. The variability of the central filling units is the “natural, continuous variability” of the process in terms of a Shewhart chart. The heads add another source of variability. A different methodology needs to be implemented …

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Orca Research Report, Jeanna Chilton, Dr. Gary Lawlor Jan 2014

Orca Research Report, Jeanna Chilton, Dr. Gary Lawlor

Journal of Undergraduate Research

The work I was able to do for the research on the minimal surface area of the octahedron was time consuming, but unfortunately did not bring about any profound knowledge for anyone besides myself.

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Fast Simulation Methods For Electrons In A Penning Trap, Brent A. Chipman, Dr. Ross Spencer Jan 2014

Fast Simulation Methods For Electrons In A Penning Trap, Brent A. Chipman, Dr. Ross Spencer

Journal of Undergraduate Research

The motivation for this work comes from the paper “Parametrically Pumped Electron Oscillators” by J. Tan and G. Gabrielse (1). Tan and Gabrielse describe a number of unexplained behavior exhibited by electrons confined in a parametrically pumped penning trap. In order to gain a better understanding of the mechanisms behind the behavior, numerical simulations of the trap are necessary. Though the equations of motion for the electrons are relatively easy to write and solve, the amount of computing time required makes this approach practically impossible. The purpose of my research was to develop a faster method for solving the problem.

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Constructing The Remote Observatory For Variable Object Research, Jason A. Gilbert, Dr. J. Ward Moody Jan 2014

Constructing The Remote Observatory For Variable Object Research, Jason A. Gilbert, Dr. J. Ward Moody

Journal of Undergraduate Research

Scientists who attempt to unravel the mysteries of the universe have some physical limitations to deal with in their quest. For example, an observer must stay up all night to operate the telescopes that record the data. There are now automated telescopes that allow the scientist to enter a list of objects (stars, asteroids, planets, galaxies, etc.) into the telescope’s computer, and the telescope will move by itself to each one, taking and recording data throughout the course of the night. Some telescopes can even be operated remotely so the scientists can run them from their offices, or even their …

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Measurement Techniques And Computational Methods For Acoustic Data In Concert Halls, Gordon Dix, Dr. Tim Leishman Jan 2014

Measurement Techniques And Computational Methods For Acoustic Data In Concert Halls, Gordon Dix, Dr. Tim Leishman

Journal of Undergraduate Research

Designing and constructing a world-class concert hall is the culmination of many different, yet interrelated, disciplines. The architects must make the building structurally sound, while preserving its aesthetic beauty. Electricity, water, air conditioning, heating, and many other aspects of the inner workings of the hall must be designed and installed properly, while keeping in mind the intent of the structure. Acoustic consultants will often work closely with the architects to ensure that the hall has no acoustic flaws. An acoustical plan for the building must take into account many of the design features of the hall and can become quite …

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Multi-Scale Neotectonic Study Of The Clear Lake Fault Zone In The Sevier Desert Basin (Central Utah), Brandon D. Heiner Jan 2014

Multi-Scale Neotectonic Study Of The Clear Lake Fault Zone In The Sevier Desert Basin (Central Utah), Brandon D. Heiner

Theses and Dissertations

A multi-scale high-resolution geophysical and geological study was conducted in the Sevier Desert, central Utah, found within the Colorado Plateau-Basin and Range Transition Zone. The region is marked by with Quaternary volcanics and faulting as young as 660 yr B.P., with many fault scarps thought to have the potential for 7+ magnitude earthquakes. Three locations within the Sevier Desert which represent three different tectonic expressions of possible faulting at the surface were selected. These include a location found within surface sedimentation, a location with surface sedimentation and sub-surface basalts and a location with basalts, at the surface with very limited …

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Collisional Dynamic Elements Of The Pyrazine - N2o System:Middle And Low J States, La Moyne Tyler Mix Jan 2014

Collisional Dynamic Elements Of The Pyrazine - N2o System:Middle And Low J States, La Moyne Tyler Mix

Theses and Dissertations

Unimolecular reactions based on the Lindemann - Hinchelwood mechanism are important to understanding combustion and atmospheric processes. The main feature of this mechanism is the energy transfer probability distribution function, P(E',E). We have chosen to study P(E',E) through gas phase collisional dynamics probed with IR transient absorption spectroscopy. Post-collision absorption line widths for the pyrazine-N2O system are used to calculate lab frame translational temperatures. The translational temperatures reveal that collisions with large rotational energy transfer also transfer large amounts of translational energy. For J states >47 the relationship is linear indicating a constant impact parameter. Line widths for J=47 through …

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How Well Does Multiple Ocr Error Correction Generalize?, William B. Lund, Eric K. Ringger, Daniel D. Walker Jan 2014

How Well Does Multiple Ocr Error Correction Generalize?, William B. Lund, Eric K. Ringger, Daniel D. Walker

Faculty Publications

As the digitization of historical documents, such as newspapers, becomes more common, the need of the archive patron for accurate digital text from those documents increases. Building on our earlier work, the contributions of this paper are: 1. in demonstrating the applicability of novel methods for correcting optical character recognition (OCR) on disparate data sets, including a new synthetic training set, 2. enhancing the correction algorithm with novel features, and 3. assessing the data requirements of the correction learning method. First, we correct errors using conditional random fields (CRF) trained on synthetic training data sets in order to demonstrate the …

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A Mathematical Model Of Collagen Lattice Contraction, J. C. Dallon, Emily J. Evans, H Paul Erhlich Jan 2014

A Mathematical Model Of Collagen Lattice Contraction, J. C. Dallon, Emily J. Evans, H Paul Erhlich

Faculty Publications

Two mathematical models for fibroblast-collagen interaction are proposed which reproduce qualitative features of fibroblast populated collagen lattice contraction in time. Both models are force based and model the cells as individual entities with discrete attachment sites however the collagen lattice is modeled differently for each model. In the collagen lattice model the lattice is more interconnected and formed by triangulating nodes to form the fibrous structure. In the collagen fiber model the nodes are not triangulated, are less interconnected, and the collagen fibers are modeled as a string of nodes. Both models suggest that the overall increase in stress of …

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Counting Threshold Graphs And Finding Inertia Sets, Christopher Abraham Guzman Dec 2013

Counting Threshold Graphs And Finding Inertia Sets, Christopher Abraham Guzman

Theses and Dissertations

This thesis is separated into two parts: threshold graphs and inertia sets. First we present an algorithmic approach to finding the minimum rank of threshold graphs and then progress to counting the number of threshold graphs with a specific minimum rank. Second, we find an algorithmic and more automated way of determining the inertia set of graphs with seven or fewer vertices using theorems and lemmata found in previous papers. Inertia sets are a relaxation of the inverse eigenvalue problem. Instead of determining all the possible eigenvalues that can be obtained by matrices with a specific zero/nonzero pattern we restrict …

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Geology Of The Birdseye 7.5-Minute Quadrangle, Utah County, Utah:Â Implications For Mid-Cenozoic Extension And Deposition Of The Moroni Formation, Don L. Bagshaw Dec 2013

Geology Of The Birdseye 7.5-Minute Quadrangle, Utah County, Utah:Â Implications For Mid-Cenozoic Extension And Deposition Of The Moroni Formation, Don L. Bagshaw

Theses and Dissertations

Geologic structures within the Birdseye 7.5 minute quadrangle Utah County, Utah have been related by previous workers to both the Jurassic Arapien Shale diapirism and to the mid-Cenozoic extensional collapse of the Charleston-Nebo Thrust. Whichever model proves valid, it will have implications for oil exploration and interpretation of the subsurface geologic structure in the region. A detailed map of the quadrangle was constructed to better constrain which mechanism was responsible for the deformation. Exposures of Arapien Shale near, and within the Birdseye quadrangle show no evidence of diapiric movement. Arapien involvement in the deformation of Tertiary rocks in the center …

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Development And Validation Of An Automated Directivity Acquisition System Used In The Acquisition, Processing, And Presentation Of The Acoustic Far-Field Directivity Of Musical Instruments In An Anechoic Space, Nicholas J. Eyring Dec 2013

Development And Validation Of An Automated Directivity Acquisition System Used In The Acquisition, Processing, And Presentation Of The Acoustic Far-Field Directivity Of Musical Instruments In An Anechoic Space, Nicholas J. Eyring

Theses and Dissertations

A high spatial resolution acoustic directivity acquisition system (ADAS) has been developed to acquire anechoic measurements of the far field radiation of musical instruments that are either remote controlled or played by musicians. Building upon work performed by the BYU Acoustic Research Group in the characterization of loudspeaker directivity, one can rotate a musical instrument with sequential azimuthal angle increments under a fixed semicircular array of microphones while recording repeated notes or sequences of notes. This results in highly detailed and instructive directivity data presented in the form of high-resolution balloon plots. The directivity data and corresponding balloon plots may …

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Synthesis, Characterization, And Application Of High Surface Area, Mesoporous, Stabilized Anatase Tio2 Catalyst Supports, Rebecca Elizabeth Olsen Dec 2013

Synthesis, Characterization, And Application Of High Surface Area, Mesoporous, Stabilized Anatase Tio2 Catalyst Supports, Rebecca Elizabeth Olsen

Theses and Dissertations

Nanomaterials have attracted substantial attention in the area of catalysis due to the unique properties they exhibit such as high surface areas, intricate pore networks and unique morphologies. TiO2 has attracted attention as a catalyst since the discovery of its high photocatalytic activity by Fuishima and Honda in 1972. Given its high thermal stability, low cost, low environmental impact, and versatility, TiO2 is a widely used commercial catalyst and catalyst support. TiO2 is used in many applications such as photocatalysis is also an excellent support material for noble metals in a number of oxidative synthesis and pollution-control reactions. Though TiO2 …

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Record Linkage, Stasha Ann Bown Larsen Dec 2013

Record Linkage, Stasha Ann Bown Larsen

Theses and Dissertations

This document explains the use of different metrics involved with record linkage. There are two forms of record linkage: deterministic and probabilistic. We will focus on probabilistic record linkage used in merging and updating two databases. Record pairs will be compared using character-based and phonetic-based similarity metrics to determine at what level they match. Performance measures are then calculated and Receiver Operating Characteristic (ROC) curves are formed. Finally, an economic model is applied that returns the optimal tolerance level two databases should use to determine a record pair match in order to maximize profit.

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Nonlinear Spectroscopic Investigation Of Adsorption To C-18 Model Stationary Phase, Anthony D. Peterson Dec 2013

Nonlinear Spectroscopic Investigation Of Adsorption To C-18 Model Stationary Phase, Anthony D. Peterson

Theses and Dissertations

Reversed-phase liquid chromatography (RPLC) is a commonly used separation technique in chemistry. Nevertheless, the mechanistic interactions at the molecular level among the eluent, analyte, and the stationary phase are not fully understood. Because of this limited understanding, optimization of the separation must be done experimentally. Learning more about molecular interactions should aid in improving separations. We are currently using second-harmonic generation (SHG) spectroscopy to investigate how analytes adsorb to the surface. SHG is a spectroscopic technique that produces signal only at places of non-isotropic symmetry; this typically occurs at surfaces. SHG can be used to produce surface isotherms of test …

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