Feedback Control of Particle Positions using Electric Fields and Chemical Gradients

Programmable self-assembly is a promising route to new biomaterial and metamaterial synthesis methods. An important step towards programmable self-assembly is moving component parts to desired locations. We do this by designing and simulating a controller that modifies an external field to move particles on desired paths. We first design a controller using electric fields by modifying established methods, then we apply the insights gained from the electric field controller to a chemical controller that uses model predictive control

Interannual variability in North American grassland biomass/productivity detected by SeaWinds scatterometer backscatter

We analyzed 2000–2004 growing-season SeaWinds Ku-band microwave backscatter and MODIS leaf area index (LAI) data over North America. Large anomalies in mid-growing-season mean backscatter and LAI, relative to 5-year mean values, occurred primarily in the western Great Plains; backscatter and LAI anomalies had similar spatial patterns across this region. Backscatter and LAI time series data for three ∼103 km2 regions in the western Great Plains were strongly correlated (r2 ∼ 0.6–0.8), and variability in mid-growing season values was well-correlated with annual precipitation (October through September). The results indicate that SeaWinds backscatter is sensitive to interannual variability in grassland biomass/productivity, and can provide an assessment that is completely independent of optical/near-infrared remote sensing instruments

A high resolution gravity survey for the detection of Pleistocene aquifers underlying the Fort Berthold Indian Reservation, North Dakota

A high resolution gravity survey was performed over portions of McLean, Mountrail, and Ward Counties in central North Dakota during the fall and winter of 1990-1991. The study was performed to locate and map Pleistocene sand and gravel aquifers. Well data indicate that aquifers beneath the study area range in thickness from 1 to 60 meters. The Bouguer gravity anomalies resulting from these shallow aquifers was estimated to be on the order of 1 to 2 mgals. Previous studies have focused on available well data and by mapping topographic lows. Due to the inferential nature of these studies, the detailed gravity method was chosen as an attractive and cost-effective method of further defining these aquifers. Station locations were established at 0.4 km spacings along accessible roads using the Global Positioning Satellite system. Of the 4000 stations that were occupied, approximately 2700 station locations were satisfactorily produced. The gravity readings were obtained by using three La Coste and Romberg Model G gravity meters. Corrections for meter calibration, solar and lunar tides, instrument drift, station latitude, and elevation were made by the computer program GRAVPAC (LaCoste and Romberg, 1989). The resulting Bouguer gravity anomalies were examined for suspect data. Questionable data were removed. Strong regional components to the gravity field necessitated the use of filtering methods. These methods included using published data, upward continuation, and wavelength filtering. The upward continuation and. wavelength filtering were performed using the computer program FFTFIL (Hildenbrand, 1983). Both the published data and the upward continuation methods produced reasonable regional anomaly patterns, but difficulties were encountered when attempting to remove the regional field from the Bouguer gravity anomalies. The wavelength filtering method yielded satisfactory results using a filter window of 1.5 km to 10 km. The regional field was compared. With structure contour maps produced from deep oil well data to ensure that an appropriate field had been removed. A three-dimensional computer modelling program was written to simulate the observed gravity anomalies. Forward modelling was then performed by adjusting density contrast, depth and thickness parameters. Shallow water well data were used to establish initial model parameters. The modelling generated reasonable results which made it possible to infer probable channel locations, depths, and thicknesses. The major limitations of the computer modelling were lengthy processing times and limited geologic data. The filtered gravity signals show several discernible low anomaly patterns which are interpreted to be stream channel aquifers. Aquifers with significant density contrasts (\u3e0.2 g/cm3) and sufficient areal extent and thicknesses were located by this method

PMKNS for PIE: Parsed Morphological KATR Networks of Sanskrit for Proto-Indo-European

In this thesis, I construct two computational networks for Sanskrit to test theories of nominal accentuation as a way of examining the simplicity of each theory. I will be examining the Paradigmatic Approach and the Compositional Approach to nominal accentuation. For the Paradigmatic Approach, nominals are categorized into mobile and static categories based on how the accent appears in the paradigm (Fortson 2010). For the Compositional Approach, accent mobility is a result of the combination of morphemes and their inherent accent states (Kirparsky 2010). To construct these networks, I use the KATR extension to the DATR language for lexical knowledge representation (Finkel et al. 2002). In Chapter 1, I give an overview of Proto-Indo-European (PIE) accentuation and KATR. Chapter 2 presents my methods and connects the hypothetical nature of PIE to the well-documented Indo-European (IE) language Sanskrit. In Chapters 3 and 4, I use a guided derivation of a Sanskrit r-stem nominal pitr̥- and a Sanskrit a-stem nominal sukha- to walk us through each step. Chapter 5 is an analysis of my results for the two networks from chapters 3 and 4 and then the overall conclusions I have drawn from the project and suggests further areas of expansion