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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Quantumness And Coherence In Photosynthesis, Brian Doolittle
Quantumness And Coherence In Photosynthesis, Brian Doolittle
Honors Theses
Long-lived oscillations lasting up to 1800 fs have been observed in the Fenna--Mathews--Olsen (FMO) Pigment-Protein complex. It is unclear if the oscillations are quantum or classical in origin. Quantized intra-pigment normal modes are responsible for these long-lived oscillations. In this thesis we simulate a bacteriachlorophyll dimer in the FMO Complex at physiological conditions. Our model describes two electronically coupled pigments coupled to the vibrational protein environment. Our goal is to find system parameters that allow long-lived quantum coherences to exist in photosynthetic complexes. We calculate the time evolution of our system's density matrix using the numerically exact quantum adiabatic path …
The Fluvial Sequence Of A Latest Changhsingian, Pre-Pt Extinction River Complex, Eastern Cape Province, South Africa, Tara Chizinski
The Fluvial Sequence Of A Latest Changhsingian, Pre-Pt Extinction River Complex, Eastern Cape Province, South Africa, Tara Chizinski
Honors Theses
The Permian–Triassic mass extinction, dated between 251.941 ± 0.037 and 251.880 ± 0.0371 Ma, is well documented in the marine record, but details of the event on land are still ambiguous and widely debated within the scientific community. This project focuses on the stratigraphic record leading up to the PT boundary at one of the critical sections in the Karoo Basin of South Africa, Wapadsberg Pass. A transition in river styles is reported to have occurred across the landscape from meandering Permian sandstone-dominated channels to Triassic braided complexes. This transition can be recorded by architectural elements, which reflect sensitive variations …
Deformation Mechanisms In The Metasedimentary Rocks Within The Kellyland Fault Zone, Washington County, Maine, Morgan E. Monz
Deformation Mechanisms In The Metasedimentary Rocks Within The Kellyland Fault Zone, Washington County, Maine, Morgan E. Monz
Honors Theses
This study focuses on a high-strain, strike-slip shear zone that juxtaposed metasedimentary rocks and a homogenous granite near the brittle-ductile transition, at a depth of 15-20 km. The metasedimentary rocks of the Flume Ridge Formation (FRF) exhibit a progressive deformation gradient of phase mixing and increasing fabric intensity across strike, northwest-to-southeast, approaching the center of the shear zone. Deformation mechanisms were controlled by metasomatic reactions in a fluid-rich fault zone. During deformation, biotite and potassium feldspar in the metasedimentary rocks reacted to form phengite—a much weaker phase. The nucleation and growth of weak phases, combined with phase mixing, decreased the …
Influence Of The Sea Surface Microlayer On Ozone Deposition Velocity, Kathryn Moore
Influence Of The Sea Surface Microlayer On Ozone Deposition Velocity, Kathryn Moore
Honors Theses
The biogeochemical cycles of both iodine and ozone are strongly linked to human health and global climate and are tightly coupled through chemical processes occurring in the surface ocean and troposphere. The concentration and distribution of these compounds have the potential to drive the oxidizing capacity and suite of chemical reactions occurring in the marine boundary layer. However, modeling coupled ocean-atmosphere systems involving them is challenging because of a limited understanding of the magnitude and dominant mechanisms controlling the fluxes of both species, in addition to temporally and spatially heterogeneous distributions of ozone and iodine in the sea surface and …
The Impact Of Dams On Nitrogen Cycling In The Messalonskee Stream, Rebecca K. Forgrave
The Impact Of Dams On Nitrogen Cycling In The Messalonskee Stream, Rebecca K. Forgrave
Honors Theses
The Messalonskee Stream in central Maine has five hydroelectric dams on 16.6km. Each dam drastically changes the flow regime of the stream, dividing it into segments with different patterns of sediment settling and organic matter retention. I investigated how these disruptions impact nitrogen cycling, specifically nitrification rates above and below each dam. I expected higher nitrification rates above the dams, where levels of organic matter are higher, and lower rates below the dam where scouring removes organic matter and fine sediment from the streambed. I measured sediment nitrification rates with a nitrapyrin-inhibition assay and potential drivers of nitrification including sediment …
Deformation Mechanisms In Mylonites At Fletcher Peak, Washington County, Me, Ariana S. Boyd
Deformation Mechanisms In Mylonites At Fletcher Peak, Washington County, Me, Ariana S. Boyd
Honors Theses
Mylonite formation and development is dependent on a number of factors including temperature, strain rate, and fluid fugacity. All three factors affect flow stress and viscosity; thus, a variance in each will affect the development of mylonites. This study focuses on factors leading to the formation of mylonite surrounded by ultramylonite of the same protolith, along-strike to one another at the center of a fault zone. The rocks in question are from the Deblois granite cut by the Kellyland fault zone, a ductile strike-slip fault zone within the larger Norumbega fault system in eastern Maine. The Deblois granite as a …
The Effect Of Azo Textile Dyes On Gross Primary Production And Community Respiration In An Artificial Environment, Theresa L. Petzoldt
The Effect Of Azo Textile Dyes On Gross Primary Production And Community Respiration In An Artificial Environment, Theresa L. Petzoldt
Honors Theses
Azo dyes are the largest category of textile dyes in production today, with over 100,000 tons of dye produced yearly in the United States. Ten to fifty percent of this dye is not fixed to the fabric during the textile production process, and is therefore discarded as effluent. Because dye waste is difficult to process in wastewater treatment facilities, it is important to understand how this waste affects aquatic systems using a whole ecosystem approach. This study used an artificial stream to model the effects of four azo dyes on benthic biofilm production and respiration. Dyes were found to have …
The Talbot Effect, Malia Kawamura
The Talbot Effect, Malia Kawamura
Honors Theses
The goal of this project is to experimentally investigate the optical Talbot effect and the electron Talbot effect. The Talbot effect is a near-field diffraction effect which occurs when plane waves are incident upon a grating. The Talbot effect creates full grating revivals at integral Talbot lengths and revivals with greater spatial periodicity at fractional Talbot lengths. We use a green helium neon laser and Ronchi rulings to take CCD camera images of the fractional Talbot revivals directly. Additionally, a photodiode records light intensity as a function of time as a second identical grating is moved to verify the presence …