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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Un'Analisi della Variazione Lessicale Regionale Nell’Inglese di California Attraverso le Ricerche in Rete Limitate per Sito / AN ANALYSIS OF REGIONAL LEXICAL VARIATION IN CALIFORNIA ENGLISH USING SITE-RESTRICTED WEB SEARCHES

ASNAGHI, COSTANZA 12 March 2013 (has links)
Lo studio esamina la variazione lessicale regionale in forma scritta nell’inglese standard in California. Attraverso ricerche in rete limitate a 336 siti di giornali online con sede in 270 città in California, vengono raccolti i valori di 45 variabili continue di alternanze lessicali e quindi calcolati come proporzioni. Tecniche statistiche di autocorrelazione spaziale globale e locale analizzano i valori. I risultati delle analisi, riportati in 90 mappe, confermano la distribuzione regionale delle variabili in California. Le 45 variabili lessicali sono poi esaminate con tecniche statistiche multivariate per individuare le relazioni linguistiche tra le città della California esaminate. L’analisi fattoriale, che rappresenta il 50,5% della variazione nei dati, evidenzia tre aree nella distribuzione regionale lessicale: nord/sud, urbano/rurale, e aree centrali e basso meridionali/aree alto meridionali e del nord. L’analisi dei cluster gerarchica distingue inoltre sei regioni dialettali principali in California: quella del Nord, quella di Sacramento-Santa Cruz, quella della San Francisco Bay Area, quella centrale, quella alto meridionale, e quella basso meridionale. Cinque mappe multivariate sono fornite nella tesi. La spiegazione dei risultati si basa sia su modelli di insediamento storico che su una spiegazione socio-culturale, che si riflettono nel linguaggio in California. / The study examines regional lexical variation in written Standard California English. The values​of 45 continuous lexical alternation variables are gathered through site-restricted web searches in 336 online newspaper websites based in 270 locations in California and then calculated as proportions. Statistical techniques analyze global and local spatial autocorrelation values. The results of the analysis, reported in 90 maps, confirm the regional distribution of the variables in California. The 45 lexical variables are then analyzed with multivariate techniques to identify the linguistic relations between the surveyed California cities. Factor analysis, which accounts for 50.5% of the variation in the data, highlights three areas in the regional lexical distribution: north/south, urban/rural, central and lower southern/upper southern and northern areas. The hierarchical cluster analysis also distinguishes six major dialect regions in California: the North dialect region, the Sacramento-Santa Cruz dialect region, the San Francisco Bay Area dialect region, the Central dialect region, the Upper Southerns dialect region, and the Lower Southern dialect region. Five multivariate maps are provided in the thesis. The explanation of the results is based both on historical settlement patterns and on a socio-cultural explanation, which are reflected in the language in California.
12

Natural and Anthropogenic Sources Controlling Regional Groundwater Geochemistry on the Niagara Peninsula

Smal, Caitlin January 2017 (has links)
Groundwater chemistry on the Niagara Peninsula has been identified as highly mineralized in comparison to groundwaters collected from the same bedrock formations elsewhere in southern Ontario. Three geochemical zones were discerned using hierarchical cluster analysis and other geochemical and isotopic methods. The Escarpment Zone, located along the Niagara and Onondaga Escarpments, is characterized by unconfined aquifer conditions, parameters reflective of surficial contaminants, including road salt, and elevated HCO3, DOC, NO3-, coliform bacteria and tritium. In contrast, in the Salina Zone thick, low-permeability sediments and gypsiferous bedrock results in highly mineralized groundwaters with Ca-SO4 geochemical facies and elevated S2-, Ca2+, Mg2+, K+, Na+, SO42-, Cl-, Br-, Sr2+, NH4+ and CH4. The Guelph Zone contains the lowest electrical conductivity of the three zones and elevated F-. Outliers exist with groundwater geochemistry that differs from the local geochemical zone and the host aquifer. These sites have elevated SO42- (>1000 to 5200 mg/L) with depleted δ34SSO4 (-2.2 to 14.3‰ VCDT) signatures that differs starkly from Devonian and Silurian evaporites (~20 to 32 ‰) in the host formations. This exogenic SO4 was identified in a cross-formational northeast – southwest linear trend crossing three major groundwater flow systems. The lack of down-stream impact in these systems and tritium groundwater ages that are typically only decades old indicate a young, non-geological origin and implicate anthropogenic activities. Additionally, nine samples were identified with elevated methane concentrations and δ13CCH4 signatures within the thermogenic range. As thermogenic methane is not produced within shallow aquifers and would be short-lived in the presence of the ubiquitous sulfate, these samples imply recent upward migration of methane from depth through vertical conduits. Taken together, the evidence supports large-scale upward movement of fluids in the centre of the Niagara geochemical anomaly and more sporadic upward transport of gases over a wider area of the peninsula. The most likely vector is through corroded and leaking casings or boreholes of abandoned (century) gas wells that are common across the peninsula. / Thesis / Master of Science (MSc)
13

Atomic Layer Deposition and High Sensitivity-Low Energy Ion Scattering for the Determination of the Surface Silanol Density on Glass and Unsupervised Exploratory Data Analysis with Summary Statistics and Other Methods

Gholian Avval, Tahereh 18 July 2022 (has links)
With the increasing importance of hand-held devices with touch displays, the need for flat panel displays (FPDs) will likely increase in the future. Glass is the most important substrate for FPD manufacturing, where both its bulk and surface properties are critical for its performance. Many properties of the glass used in FPDs are controlled by its surface chemistry. Surface hydroxyls are the most important functional groups on a glass surface, which control processes that occurs on oxide surfaces, including wetting, adhesion, electrostatic charging and discharge, and the rate of contamination. In this dissertation, I present a new approach for determining surface silanol densities on planar surfaces. This methodology consists of tagging surface silanols using atomic layer deposition (ALD) followed by low energy ion scattering (LEIS) analysis of the tags. The LEIS signal is limited to the outermost atomic layer, i.e., LEIS is an extremely surface sensitive technique. Quantification in LEIS is straightforward in the presence of suitable reference materials. An essential part of any LEIS measurement is the preparation and characterization of the sample and appropriate reference materials that best represent the samples. My tag-and-count method was applied to chemically and thermally treated fused silica. In this work, I determined the silanol density of a fully hydroxylated fused silica surface to be 4.67 OH/nm2. This value agrees with the literature value for high surface area silica powder. My methodology should be important in future glass studies. Surface Science Spectra (SSS) is an important, peer-reviewed database of spectra from surfaces. Recently, SSS has been expanding to accept spectra from new surface techniques. I created the first SSS submission form for LEIS spectra (see appendix 5), and used it to create the first SSS LEIS paper (on CaF2 and Au reference materials, see chapter 3). I also show LEIS reference spectra for ZnO, and copper in the appendix 1. The rest of my dissertation focuses on my chemometrics/informatics and data analysis work. For example, I showed the performance and capabilities of a series of summary statistics as new tools for unsupervised exploratory data analysis (EDA) (see chapter 4). Unsupervised EDA is often the first step in understanding complex data sets because it can group, and even classify, samples according to their spectral similarities and differences. Pattern recognition entropy (PRE) and other summary statistics are direct methods for analyzing data - they are not factor-based approaches like principal component analysis (PCA) or multivariate curve resolution (MCR). I show that, in general, PRE outperforms the other summary statistics, especially in image analysis, although I recommend a suite of summary statistics be used in exploring complex data sets. In addition, I introduce the concept of divided spectrum-PRE (DS-PRE) as a new EDA method and use it to analyze multiple data sets. DS-PRE increases the discrimination power of PRE. I have also prepared a guide that discusses the vital aspects and considerations for chemometrics/informatics analyses of XPS data along with specific EDA tools that can be used to probe XPS data sets, including PRE, PCA, MCR, and cluster analysis (see chapter 5). I emphasize the importance of an initial evaluation/plotting of raw data, data preprocessing, returning to the original data after a chemometrics/informatics analysis, and determining the number of abstract factors to keep in an analysis, including reconstructing the data using PCA. In my thesis, I also show the analysis of commercial automotive lubricant oils (ALOs) with various chemometrics techniques (see chapter 6). Using these methods, the ALO samples were readily differentiated according to their American Petroleum Institute (API) classification and base oil types: mineral, semi-synthetic, and synthetic.

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