Physical Sciences and Mathematics Commons^™

A Microreactor System For Measuring Size Selectivity In Porous Wo3 Sensor Materials, Meng Lu

Electronic Theses and Dissertations

Our interest in studying reactions catalyzed by high surface area W0₃ powders is based on their potential application as the active material in sensors for low level (ppb) detection of flammable or toxic gases. A series of porous W0₃ powders with both meso- and micro-porosity have been synthesized by Waghe and Tripp. Preliminary results of the response of sensors fabricated from these materials indicated the possibility of size selectivity on the molecular scale. To provide support for the hypothesis of size selectivity and understand the reaction kinetics of alcohols over the new porous W0₃ powders for sensor …

Implications Of Spatial Autocorrelation And Dispersal For The Modeling Of Species Distributions, Volker Bahn

Electronic Theses and Dissertations

Modeling the geographical distributions of wildlife species is important for ecology and conservation biology. Spatial autocorrelation in species distributions poses a problem for distribution modeling because it invalidates the assumption of independence among sample locations. I explored the prevalence and causes of spatial autocorrelation in data from the Breeding Bird Survey, covering the conterminous United States, using Regression Trees, Conditional Autoregressive Regressions (CAR), and the partitioning of variance. I also constructed a simulation model to investigate dispersal as a process contributing to spatial autocorrelation, and attempted to verify the connection between dispersal and spatial autocorrelation in species' distributions in empirical …

Climatic And Lithogenic Controls On Soil Organic Matter-Mineral Associations, Rota Wagai

Electronic Theses and Dissertations

Interactions of organic matter (OM) with soil mineral phases strongly affect the storage and dynamics of soil OM as well as other ecosystem processes. This study examined aspects of organo-mineral associations in soils at different scales. First, I assessed the potential controls of climate and parent rock type on organo-mineral associations using two sets of undisturbed tropical forest soils developed on two contrasting rocks along an altitudinal gradient in Borneo, Southeast Asia. Density fractionations showed that OM stored in surface mineral soils partitioned towards plant detritus fraction under cooler climates on both rock types. Thus climate exerted stronger control on …

Hierarchies For Event-Based Modeling Of Geographic Phenomena, Rui Zhang

Electronic Theses and Dissertations

Modeling the dynamic aspect, or change, of geographic phenomena is essential to explain the evolution of geographic entities and predict their future. Event-based modelling, describing the occurrences rather than states of geographic phenomena, gives an explicit treatment of such change, but currently does not have the support of the mechanisms to enable the shifts among different granularities of events. To account for different tasks, a hierarchical representation of the event space at different granularities is needed.

This thesis presents an event-based model; a general framework for representing events based on precondition and postcondition using Allen's temporal interval logic. It captures …

Ramanujan's Formula For The Riemann Zeta Function Extended To L-Functions, Katherine J. Merrill

Electronic Theses and Dissertations

Ramanujan's formula for the Riemann-zeta function is one of his most celebrated. Beginning with M. Lerch in 1900, there have been many mathematicians who have worked with this formula. Many proofs of this formula have been given over the last 100 years utilizing many techniques and extending the formula. This thesis provides a proof of this formula by the Mittag-Leffler partial fraction expansion technique. In comparison to the most recent proof by utilizing contour integration, the proof in this thesis is based on a more natural growth hypothesis. In addition to a less artificial approach, the partial fraction expansion technique …

Early Paleozoic Orogenesis In The Maine-Quebec Appalachians, Christopher Charles Gerbi

Electronic Theses and Dissertations

Accretionary orogens, such as the Appalachian orogen, form by episodic docking of oceanic and continental fragments. Two factors that exert significant control on the development of an accretionary orogen are: (1) the nature and source of the accreting fragments, and (2) the thermal and deformational structure of the crust. This study addresses aspects of both of these controls. In the Northern Appalachians, a long-lived but untested hypothesis suggested that Early Paleozoic accretion in western Maine, which marked the initiation of Appalachian development, involved the docking of an island arc. My goal was to test this hypothesis for the Maine-Qukbec segment …

Porphyroblast Kinematics And Crenulation Cleavage Development In The Aureole Of The Mooselookmeguntic Pluton, Western Maine, Matthew E. Dupee

Electronic Theses and Dissertations

The porphyroblastic pelitic schists of western Maine are ideal for studying the deformation and metamorphism that accompanies pluton emplacement. A regional lowpressure, high-temperature metamorphic event affected the areally extensive Silurian sediments with the thermal peak occuning ca. 404 Ma. This metamorphism produced the widespread assemblage staurolite + andalusite + biotite +I- garnet, and occurred during the late stages of development of a northeast-trending, steeply-dipping axial-surface foliation. A period of extensive plutonism accompanied and followed this Acadian-aged deformation and metamorphism. This study focuses specifically on the contact aureole of the Mooselookmeguntic pluton emplaced ca. 370 Ma. Contact metamorphism accompanied the development …

Digital Vertical Aerial Camera System For High-Resolution Site Inspections In Conservation Easment Monitoring, Kenton Williams

Electronic Theses and Dissertations

A three-level satellite to ground monitoring scheme for conservation easement monitoring has been implemented in which high-resolution imagery serves as an intermediate step for inspecting high priority sites. A digital vertical aerial camera system was developed to fulfill the need for an economical source of imagery for this intermediate step. A method for attaching the camera system to small aircraft was designed, and the camera system was calibrated and tested. To ensure that the images obtained were of suitable quality for use in Level 2 inspections, rectified imagery was required to provide positional accuracy of 5 meters or less to …

Data Structures And Algorithms For Efficient Solution Of Simultaneous Linear Equations From 3-D Ice Sheet Models, Rodney A. Jacobs

Electronic Theses and Dissertations

Two current software packages for solving large systems of sparse simultaneous l~neare equations are evaluated in terms of their applicability to solving systems of equations generated by the University of Maine Ice Sheet Model. SuperLU, the first package, has been developed by researchers at the University of California at Berkeley and the Lawrence Berkeley National Laboratory. UMFPACK, the second package, has been developed by T. A. Davis of the University of Florida who has ties with the U. C. Berkeley researchers as well as European researchers. Both packages are direct solvers that use LU factorization with forward and backward substitution. …