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- Physics (10)
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Articles 1 - 18 of 18
Full-Text Articles in Physical Sciences and Mathematics
The Biomechanics Of Ballistochory In Impatiens Pallida, Lua Del Campo
The Biomechanics Of Ballistochory In Impatiens Pallida, Lua Del Campo
Pomona Senior Theses
This research is an analysis of the explosive seed dispersal of Impatiens pallida fruit. Data was taken using high-speed video and analyzed using LoggerPro video analysis software. From the videos we discerned a qualitative model for dehiscence, a description of how the process unfolds, and from our data we deduced quantitative values for the velocity, momentum, and energy of the system. We were also able to glean a lower bound of Young’s modulus E of the fruit tissue. These results and the tools of analysis that generate them are the foundation for the development of a theoretical model of the …
H I Line Profiles Of Galaxies: Tilted Ring Models, Erica Nelson
H I Line Profiles Of Galaxies: Tilted Ring Models, Erica Nelson
Pomona Senior Theses
Two-dimensional information on the kinematics and spatial distribution of gas in spiral galaxies is encoded in radio observations of their one-dimensional 21-cm neutral hydrogen (HI) line profiles. More than ten thousand HI profiles have been published and are publicly available. In order to explore the parameter space mapped out by the 21-cm neutral hydrogen line pro file, we have modified and run a FORTRAN-based computer simulation code. We have identified 7 control parameters that define the morphology of the modelled galaxy: they describe the neutral hydrogen gas distribution (density and spatial location of the gas), characteristics of its rotation curve, …
A Study Of Interacanding And Companion Galaxies: Implications For Cosmology, Kristen Petrillo
A Study Of Interacanding And Companion Galaxies: Implications For Cosmology, Kristen Petrillo
Pomona Senior Theses
This paper examined a few different types of interacting galaxies and the implications the data has on cosmological theories. An analysis of the Holmberg Effect, Holmberg (1969)’s observation that companion galaxies tend to be near the poles of edge-on galaxies rather than in the planes, was done by reexamining the spirals viewed by Holmberg. Only using radial velocity confirmed companions to test for this effect showed that if anything, the opposite of the Holmberg effect is true. However, due to small number statistics, more edge-on spirals and their companions would have to be viewed in order to determine if this …
Shaping Graphene: An Alternative Approach, Ian W. Frank
Shaping Graphene: An Alternative Approach, Ian W. Frank
Pomona Senior Theses
With experimentation on graphene (an atomic layer of graphite) becoming more and more common it is imperative that we have the capability to shape the material beyond the random manner in which it is deposited by mechanical exfoliation. This capability would be invaluable not only for the interesting electronic and optical properties that can be obtained, but also potentially for characterizing the mechanical resonators that we have been able to fabricate here at Pomona College by suspending few-layer graphene sheets over trenches in SiO2. We propose novel methods for etching graphene that should allow us to shape the material when …
Bridging The Gender Gap In Quantum Physics, Gordon Stecklein
Bridging The Gender Gap In Quantum Physics, Gordon Stecklein
Pomona Senior Theses
Why is it important to study the gender gap in physics? Despite entering the workforce in increasing numbers over the last fifty years, women remain severely underrepresented in science and technology-related careers, particularly in positions of authority. Simultaneously, numerous studies verify that women have the ability to perform as well as – or better than – males in physics, and, when presented in certain lights, as many women as men show an interest in physics. Changes must be made in order to strive for equality and, given the changing demographic of the workforce, increase our country’s diminishing scientific prowess.
Acoustical Measurement Of The Human Vocal Tract: Quantifying Speech & Throat-Singing, Bryant R. Foresman
Acoustical Measurement Of The Human Vocal Tract: Quantifying Speech & Throat-Singing, Bryant R. Foresman
Pomona Senior Theses
The field of biological acoustics has witnessed a steady increase in the research into overtone singing, or “throat-singing,” in which a singer utilizes resonance throughout the vocal tract to sing melodies with the overtones created by a vocal drone. Recent research has explored both how a singer vocalizes in order to obtain rich harmonics from a vocal drone, as well as how further manipulations of the vocal apparatus function to filter and amplify selected harmonics. In the field of phonetics, vowel production is quantified by measuring the frequencies of vocal tract resonances, or formants, which a speaker manipulates to voice …
Determining The Agn Fraction Of Galaxy Groups, Rachel Paterno-Mahler
Determining The Agn Fraction Of Galaxy Groups, Rachel Paterno-Mahler
Pomona Senior Theses
Using the Chandra X-ray Observatory, Martini et al. (2006) found that the AGN fraction of galaxy clusters was five times higher than previous optical studies suggested. Using visual observations only, Dressler et al. (1985) estimated the AGN fraction of field galaxies to be 5%, while that of clusters was thought to be 1%. To understand the role that the environment plays in AGN fueling, the author studied a variety of environments, ranging from the field to groups to clusters. Will the AGN fraction of groups also be higher than that of the field? The author demonstrates how the AGN fraction …
Fuzzy Blackholes, Anand Murugan
Fuzzy Blackholes, Anand Murugan
Pomona Senior Theses
The fuzzball model of a black hole is an attempt to resolve the many paradoxes and puzzles of black hole physics that have revealed themselves over the last century. These badly behaved solutions of general relativity have given physicists one of the few laboratories to test candidate quantum theories of gravity. Though little is known about exactly what lies beyond the event horizon, and what the ultimate fate of matter that falls in to a black hole is, we know a few intriguing and elegant semi-classical results that have kept physicists occupied. Among these are the known black hole entropy …
The Effects Of Spin-Orbit Coupling On Gravitational Wave Uncertainties, C. L. Wainwright
The Effects Of Spin-Orbit Coupling On Gravitational Wave Uncertainties, C. L. Wainwright
Pomona Senior Theses
Paper discusses the expected uncertainty of orbital parameters of binary stars as measured by the space-based gravitational wave observatory LISA (Laser Interferometer Space Antenna) and how the inclusion of spin in the model of the binary stars affects the uncertainty. The uncertainties are found by calculating the received gravitational wave from a binary pair and then performing a linear least-squares parameter estimation. The case of a 1500 solar mass black hole that is 20 years from coalescing with a 1000 solar mass black hole--both of which are 50 x 10^6 light years away--is analyzed, and the results show that the …
A Simple Organic Solar Cell, Gordon Patrick Whyburn
A Simple Organic Solar Cell, Gordon Patrick Whyburn
Pomona Senior Theses
Finding renewable sources of energy is becoming an increasingly important component of scientific research. Greater competition for existing sources of energy has strained the world’s supply and demand balance and has increased the prices of traditional sources of energy such as oil, coal, and natural gas. The experiment discussed in this paper is designed to identify and build an inexpensive and simple method for creating an effective organic solar cell.
Investigation Of Carbon Nanotube Growth Using A Nozzle Cvd Method, James Mcfarland
Investigation Of Carbon Nanotube Growth Using A Nozzle Cvd Method, James Mcfarland
Pomona Senior Theses
This work uses a modification of the chemical vapor deposition (CVD) technique to study the effects of source gas flow geometry (and the corresponding parameters) on carbon nanotube growth. Our approach is to flow the carbon-containing source gas through a nozzle, projecting the gas stream onto targeted regions of the substrate. This technique not only allows the potential for localized nanotube growth, but also offers an interesting opportunity to provide an experimental test of theoretical nanotube growth models.
The Viscous Catenary, John Koulakis
The Viscous Catenary, John Koulakis
Pomona Senior Theses
Variational techniques are used to develop a theory for the time evolution of a thin strand of viscous fluid suspended from two points. The shape of the strand is approximated to be a parabola and energy conservation is used to derive a differential equation modeling the change in height over time. Data is collected with a high resolution camera and a strobe light to obtain the position and shape of the strand over multiple intervals of time. Three very different and unexpected types of behaviors are observed depending on the initial thickness and shape of the filament. The approximation fits …
Deep-Uv Light Emitting Diodes: An Experimental Investigation Of Characterization And Optimization Techniques, Eric M. Fraser
Deep-Uv Light Emitting Diodes: An Experimental Investigation Of Characterization And Optimization Techniques, Eric M. Fraser
Pomona Senior Theses
Light emitting diodes (LEDs) and laser diodes (LDs) have many advantages over conventional light sources. Current commercial LEDs span the spectrum from IR to near- UV. There are a variety of applications for devices that extend into the deep-UV, including biological agent detection and optical storage. The nitride material system is a set of semiconducting compounds that have wavelengths that span a broad range, from yellow to deep-UV. AlGaN has a direct bandgap that extends into the deep-UV range; we will try to grow device-quality material, deposited epitaxially using metalorganic chemical vapor deposition on sapphire substrates.
Deep-Uv Light Emitting Diodes: An Experimental Investigation Of Characterization And Optimization Techniques, Eric M. Fraser
Deep-Uv Light Emitting Diodes: An Experimental Investigation Of Characterization And Optimization Techniques, Eric M. Fraser
Pomona Senior Theses
Light emitting diodes (LEDs) and laser diodes (LDs) have many advantages over conventional light sources. Current commercial LEDs span the spectrum from IR to near- UV. There are a variety of applications for devices that extend into the deep-UV, including biological agent detection and optical storage. The nitride material system is a set of semiconducting compounds that have wavelengths that span a broad range, from yellow to deep-UV. AlGaN has a direct bandgap that extends into the deep-UV range; we will try to grow device-quality material, deposited epitaxially using metalorganic chemical vapor deposition on sapphire substrates.
Patterning Polymer Thin Films: Lithographically Induced Self Assembly And Spinodal Dewetting, Regina C. Carns
Patterning Polymer Thin Films: Lithographically Induced Self Assembly And Spinodal Dewetting, Regina C. Carns
Pomona Senior Theses
In an age in which the microchip is ubiquitous, the rewards for novel methods of microfabrification are great, and the vast possibilities of nanotechnology lie just a little ahead. Various methods of microlithography offer differing benefits, and even as older techniques such as optical lithography are being refined beyond what were once considered their upper limits of resolution, new techniques show great promise for going even further once they reach their technological maturity. Recent developments in optical lithography may allow it to break the 100-nm limit even without resorting to x-rays.
Steps Toward The Creation Of A Carbon Nanotube Single Electron Transistor, R. Matthew Ferguson
Steps Toward The Creation Of A Carbon Nanotube Single Electron Transistor, R. Matthew Ferguson
Pomona Senior Theses
This report details work toward the fabrication of a single-electron transistor created from a single-walled carbon nanotube (SWNT). Specifically discussed is a method for growing carbon nanotubes (CNTs) via carbon vapor deposition (CVD). The growth is catalyzed by a solution of 0.02g Fe(NO3)3·9H2O, 0.005g MoO2(acac)2, and 0.015g of alumina particles in 15mL methanol. SWNT diameter ranges from 0.6 to 3.0 nm. Also discussed is a method to control nanotube growth location by patterning samples with small islands of catalyst. A novel “maskless” photolithographic process is used to focus light from a lightweight commercial digital projector through a microscope. Catalyst islands …
Maskless Projection Lithography, J. David Musgraves
Maskless Projection Lithography, J. David Musgraves
Pomona Senior Theses
Photolithography is a key element of the modem integrated circuit process. It is photolithography, combined with metal deposition, that allows a three dimensional circuit to be built up on a two dimensional surface. Since it is such an important part of the semiconductor manufacturing industry, a massive base of research in this area already exists. The problem with this pre-existing research is that it is geared solely toward industrial purposes, as opposed to more academic research areas. The goal of my research is to move this industrial process into the academic setting of Pomom College.
Steps Toward The Creation Of A Carbon Nanotube Single Electron Transistor, R. Matthew Ferguson
Steps Toward The Creation Of A Carbon Nanotube Single Electron Transistor, R. Matthew Ferguson
Pomona Senior Theses
This report details work toward the fabrication of a single-electron transistor created from a single-walled carbon nanotube (SWNT). Specifically discussed is a method for growing carbon nanotubes (CNTs) via carbon vapor deposition (CVD). The growth is catalyzed by a solution of 0.02g Fe(NO3)3·9H2O, 0.005g MoO2(acac)2, and 0.015g of alumina particles in 15mL methanol. SWNT diameter ranges from 0.6 to 3.0 nm. Also discussed is a method to control nanotube growth location by patterning samples with small islands of catalyst. A novel “maskless” photolithographic process is used to focus light from a lightweight commercial digital projector through a microscope. Catalyst islands …