This thesis is a study of tunability of edge-coupled filters. Microstrip edge-coupled bandpass filters are planar structures and have advantages such as easy design procedures and simple integration into circuits. Three tuning techniques were implemented. The first technique involved the loading of one open end of each coupled into tunable capacitors. The second technique used a tunable resonator in series with the edge-coupled blocks. The final design made use of tunable feedback sections. A detailed mathematical analysis of each design was performed. MATLAB code based on the analyses was written. The MATLAB simulations were compared to Agilent Advanced Design System (ADS) simulations in order to and the minimum design parameters required to arrive at an approximate solution. ADS simulations were used to accurately determine the final design. The tunable filters with a series capacitor and feedback were fabricated on RO4003C boards from Roger's Corporation, having a dielectric constant of 3.55. The built boards were then tested with the HP 8510c network analyzer. The measured results were compared to the ADS simulations. The filter with a tuning capacitor in series with the coupled sections had high insertion loss of -20 dB and tuning range in terms of KHz. The design involving feedback had advantages over the previous design since the insertion loss was better than -14 dB and it had a tuning range of 91 MHz. It was observed from simulations that the design had an adjustable tunability range and bandwidth as the width was varied.

In non-relativistic quantum mechanics, stationary states of molecules and atoms are described by eigenvectors of the Hamiltonian operator. For one-electron systems, such as the hydrogen atom, the solution of the eigenvalue problem (Schro ̈dinger’s equation) is straightforward, and the results show excellent agreement with experiment. Despite this success, the multi electron problem corresponding to virtually every system of interest in chemistry has resisted attempts at exact solution. Perhaps the most popular method for obtaining approximate, yet very accurate results for the ground states of molecules is the coupled cluster approximation. Coupled cluster methods move beyond the simple, average field Hartree-Fock approximation by including the effects of excited configurations generated in a size consistent manner. In this paper, the coupled cluster approximation is developed from first principles. Diagrammatic methods are introduced which permit the rapid calculation of matrix elements appearing in the coupled cluster equations, along with a systematic approach for unambiguously determining all necessary diagrams. A simple error bound is obtained for the ground state energy by considering the coupled cluster equations as entries in the first column of a matrix whose eigenvalues are the exact eigenvalues of the Hamiltonian. In addition, a strategy is considered for treating the error in the ground state energy perturbatively.

Animals rely on the integration of a variety of external cues to understand and respond appropriately to their environment. The relative amounts of food and constitutively secreted pheromone detected by the nematode C. elegans determines how it will develop and grow. Starvation conditions cause the animal to enter a protective stage, termed dauer. Dauer animals are non-eating, long-lived and stress resistant. Yet, when these animals are introduced to food replete conditions they will recover from dauer and proceed into normal development. Furthermore, food restriction has been demonstrated to extend the lifespan of a wide-range of species including C. elegans. However, the exact mechanism by which food signals are detected and transduced by C. elegans to influence development and longevity remains unknown. Here, we identify a G protein-coupled receptor (GPCR) DCAR-1 that acts in two chemosensory neurons to mediate food signaling in an autophagy-related manner. The DCAR-1 ligand Dihydrocaffeic acid (DHCA) competes with dauer-inducing pheromone to promote growth. DHCA is a key intermediate in the shikimate pathway, which is required to synthesize folate and aromatic amino acids. We report that dcar-1 mutations influence dauer formation and extend wildtype lifespan via a mechanism of dietary restriction. Moreover, we show that the lifespan extension of dcar-1 mutants is completely dependent on autophagy gene atg- 18. Furthermore, our data suggests metabolites derived from shikimate are food signals that control aging and dauer development through GPCR signaling in C. elegans. These studies will contribute to the delineation of mechanisms behind the beneficial effects of dietary restriction in eukaryotic organisms. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

The Atascadero Subbasin, located on the central coast of California, is a small, hydraulically separated sub-region of the Paso Robles Groundwater Basin. Three local cities operate approximately 40 wells to pump the Subbasin for their entire water supply needs. Past studies have questioned sustainability of the Subbasin as the combined pumping rate by the three cities is nearing the perennial yield of the Subbasin. The studies have been inconclusive as some areas of the Subbasin have seen increases in water table elevation thus questioning the assessment that consumption is nearing perennial yield. The objective of this research was to perform a water balance study for the aquifer and examine sustainability of the Subbasin. Surface water and groundwater models were developed to investigate the interaction between the Salinas River Alluvium Soils and the deeper Paso Robles Formation based on pumping from different shallow and deep wells. Surface water hydrology of the Subbasin was studied using HEC-HMS, and Visual MODFLOW was used to model the aquifer. Both HEC-HMS and Visual MODFLOW was calibrated to improve simulation accuracy. HEC-HMS was used to quantify natural recharge to the aquifer and to simulate streamflow and water level for the Salinas River. HEC-GeoHMS was used to delineate the watershed, create sub-watersheds and channel networks, and to extract sub-watershed inputs that were used to build HEC-HMS from geospatial data including land use, soil and topography data. Different hydrogeologic layers were defined to represent the alluvium and deeper soils. Results show that currently the Atascadero Subbasin does not appear to be in overdraft as shallow groundwater wells pump Salinas River underflow and the alluvium appears to be providing some recharge to the deeper aquifer. These findings would provide municipal and water managers better understanding of where their water comes from, the effects of their pumping, and could help with developing sustainable management strategies for the Subbasin.

The weathering of apatite is the foundation of the phosphorus cycle and essential to life, yet little is known about the nanoscale mechanisms driving apatite weathering. Deciphering nanoscale dissolution in apatite is a significant step to understand phosphate weathering behavior, that was key to the development of life. Determining what controls apatite weathering can impact many areas of environmental and medical mineralogy such as dentistry, contaminant scavenging, geochronology, and paleoenvironment studies. The aim of this study was to characterize apatite dissolution across scales with an emphasis on the nanoscale mechanisms. Recent research on the weathering of silicate minerals at the nanoscale has provided telling evidence of a relatively new chemical weathering model referred to as coupled interfacial dissolution-precipitation (CIDR) mechanism. We hypothesize that this mechanism could be broadened to phosphate minerals. To investigate crystals of Durango fluorapatite (FAP) and hydroxyl-chlorapatite (HAP) were hydrolyzed in flow-through devices with pH 3 HNO3 solutions. Apatites used in the study were chemically and structurally characterized via Single Crystal-XRD, with particular emphasis on the anion composition and atomic arrangement. Determination of the mechanisms of dissolution was carried at multiple scales using ICP-OES chemical analysis (macroscale), SEM (microscale) and STEM-HAADF-EDS/EELS on FIB liftouts (nanoscale). At the macroscale, The anionic composition of the apatite controlled its weathering rate. As expected, HAP dissolution occurred at faster rates compared to FAP. SEM characterization of the crystal surfaces pre- and post-dissolution revealed the development of etch pits during dissolution, however, more pronounced for FAP than HAP. Observation of the mineral/solution interface at the nanoscale using STEM-HAADF revealed the development of a nanometric amorphous layer likely depleted in Ca compared to P. The observation of a sharp crystalline/amorphous transition and 5 to 15 nanometers thick amorphous surface altered layer, associated with a depletion in Ca suggests that similar to silicate, apatite is subject to a coupled interfacial dissolution-reprecipitation mechanism. This potential discovery could transform our understanding of phosphate behavior in medical and environmental mineralogy fields.

The development of a high-resolution coupled one-dimensional/two-dimensional hydrodynamic model of Charles City, Iowa is presented in this study as part of a larger Iowa Flood Center initiative to create a library of steady inundation maps for communities in Iowa which have a high risk of flooding. Channel geometry from bathymetric surveys and surface topography from LiDAR were combined to create the digital elevation model (DEM) used in numerical simulations. Coupled one- and two-dimensional models were used to simulate flood events; the river channel and structures were modeled one-dimensionally, and the floodplain was modeled two-dimensionally. Spatially distributed roughness parameters were estimated using the 2001 National Land Cover Dataset. Simulations were performed at a number of mesh resolutions, and the results were used to investigate the effectiveness of re-sampling simulation results using higher- resolution DEMs. The effect of removing buildings from the computational mesh was also investigated. During 2011, the stream channel geometry is being changed as part of a recreational park in downtown Charles City. After incorporating the planned changes to the stream channel, the model was used to create a library of steady inundation maps which are available on the Iowa Flood Center website.

No description available.

This project involved designing and building a radiochromic film (RCF) densitometer using a still digital camera as the light detector and light emitting diode, LED, as the light source. The behaviour of the LED and charged coupled device (CCD) in the still digital camera, under different light exposure settings (by changing LED current and camera shutter speed) were measured and an optimal setting was determined. Additionally, methods were devised and tests were carried out in order to spread the illumination area of the single light source. Uniform spreading of the LED illumination area was possible by the use of two diffusers placed at an optimum separation distance that was determined in this work. The usefulness of this custom-made RCF densitometer was demonstrated by using this device to image exposed RCF and using the film analysis software, Image J, to determine the film absorbed dose. Two clinical situations were examined: open and virtual wedge radiation beams. It was concluded that still digital cameras can be used in RCF densitometers provided they can capture and store raw images, a single diffused LED can illumination an area large enough for RCF densitometry and appropriate film analysis software is needed to extract and handle the large volume of greyscale data from the RCF.

The domain of medical imaging analysis has burgeoned in recent years due to the availability and affordability of digital radiographic imaging equipment and associated algorithms and, as such, there has been significant activity in the automation of the medical diagnostic process. One such process, cephalometric analysis, is manually intensive and it can take an experienced orthodontist thirty minutes to analyse one radiology image. This thesis describes an approach, based on genetic programming, neural networks and machine learning, to automate this process. A cephalometric analysis involves locating a number of points in an X-ray and determining the linear and angular relationships between them. If the points can be located accurately enough, the rest of the analysis is straightforward. The investigative steps undertaken were as follows: Firstly, a previously published method, which was claimed to be domain independent, was implemented and tested on a selection of landmarks, ranging from easy to very difficult. These included the menton, upper lip, incisal upper incisor, nose tip and sella landmarks. The method used pixel values, and pixel statistics (mean and standard deviation) of pre-determined regions as inputs to a genetic programming detector. This approach proved unsatisfactory and the second part of the investigation focused on alternative handcrafted features sets and fitness measures. This proved to be much more successful and the third part of the investigation involved using pulse coupled neural networks to replace the handcrafted features with learned ones. The fourth and final stage involved an analysis of the evolved programs to determine whether reasonable algorithms had been evolved and not just random artefacts learnt from the training images. A significant finding from the investigative steps was that the new domain independent approach, using pulse coupled neural networks and genetic programming to evolve programs, was as good as or even better than one using the handcrafted features. The advantage of this finding is that little domain knowledge is required, thus obviating the requirement to manually generate handcrafted features. The investigation revealed that some of the easy landmarks could be found with 100\% accuracy while the accuracy of finding the most difficult ones was around 78\%. An extensive analysis of evolved programs revealed underlying regularities that were captured during the evolutionary process. Even though the evolutionary process took different routes and a diverse range of programs was evolved, many of the programs with an acceptable detection rate implemented algorithms with similar characteristics. The major outcome of this work is that the method described in this thesis could be used as the basis of an automated system. The orthodontist would be required to manually correct a few errors before completing the analysis.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.