With the proliferation of wireless communications and rapid advances in technologies, algorithms for efficiently answering queries about large number of spatial data are needed. Spatial data consists of spatial objects including data of higher dimension. Neighbor finding is one of the most important spatial operations in the field of spatial data structures. In recent years, many researchers have focused on finding efficient solutions to the nearest neighbor problem (NN) which involves determining the point in a data set that is the nearest to a given query point. It is frequently used in Geographical Information Systems (GIS). A block B is said to be the neighbor of another block A, if block B has the same property as block A has and covers an equal-sized neighbor of block A. Jozef Voros has proposed a neighbor finding strategy on images represented by quadtrees, in which the four equal-sized neighbors (the east, west, north, and south directions) of block A can be found. However, based on Voros's strategy, the case that the nearest neighbor occurs in the diagonal directions (the northeast, northwest, southeast, and southwest directions) will be ignored. Moreover, there is no total ordering that preserve proximity when mapping a spatial data from a higher dimensional space to a 1D-space. One way of effecting such a mapping is to utilize space-filling curves. Space-filling curves pass through every point in a space and give a one-one correspondence between the coordinate and the 1D-sequence number of the point. The Peano curve, proposed by Orenstein, which maps the 1D-coordinate of a point by simply interleaving the bits of the X and Y coordinates in the 2D-space, can be easily used in neighbor finding. But with the data ordered by the RBG curve or the Hilbert curve, the neighbor finding would be complex. The RBG curve achieves savings in random accesses on the disk for range queries and the Hilbert curve achieves the best clustering for range queries. Therefore, in this thesis, we first show the missing case in the Voros's strategy and show the ways to find it. Next, we show that the Peano curve is the best mapping function used in the nearest neighbor finding. We also show the transformation rules between the Peano curve and the other curves such that we can efficiently find the nearest neighbor, when the data is linearly ordered by the other curves. From our simulation, we show that our proposed two strategies can work correctly and faster than the conventional strategies in nearest neighbor finding. Finally, we present a revised version of NA-Trees, which can work for exact match queries and range queries from a large, dynamic index, where an exact match query means finding the specific data object in a spatial database and a range query means reporting all data objects which are located in a specific range. By large, we mean that most of the index must be stored in secondary memory. By dynamic, we mean that insertions and deletions are intermixed with queries, so that the index cannot be built beforehand.

No description available.

The aim of this study was to estimate how different filling materials affect the mobilization of pollution residue in remediated soil. The aim was also to assess criteria that should be fulfilled for the soil properties of these filling materials. The study was partly based on target value calculations where the impact of varied TOC, hydraulic conductivity and porosity affected the mobility of toluene, trichloroethene, benso(a)pyrene and arsenic residue in the soil. An evaluation of the potential mobility of soil pollution residues where filling materials had been used was carried out for five different locations in Sweden. Soil samples were collected before remediation of contaminated soil, and afterwards when the fillings were restored. Sample analyzes were made for TOC and soil water. The results from the study show that the TOC and porosity content in filling materials has a significant impact on the mobility of soil pollution residues. Filling materials with less TOC than the remediated soil will contribute to an increased mobility of organic pollution residues to the air, surface water and groundwater, whilst lower soil porosity, or rather lower soil water content will contribute to an increased mobility of airborne pollution residues. The results also show that in Sweden the use of filling materials with both lower TOC and soil water content is common. To avoid an increased mobilization of pollution residues from remediated soils, filling materials should contain TOC and soil water equals the contents in the remediated soil.

This thesis discusses the chemistry and physics of Cu and H2O on ZnO surfaces, based primarily on results from quantum chemical calculations. The underlying context is heterogeneous catalysis, where Cu/ZnO-mixtures are used in the industrial synthesis of methanol and in the water gas shift reaction. Electron transfer between small Cu clusters and ZnO is central to this thesis, as are the design and use of models that can describe realistic and very large-scale ZnO surface structures while still retaining the electronic nature of the system. Method and model enhancements as well as tests and validations constitute a large part of this thesis. The thesis demonstrates that the charges of small Cu clusters, adsorbed on the non-polar ZnO(10-10) surface, depend on whether the Cu clusters contain an even or odd number of atoms, and whether water is present (water can induce electron transfer from Cu to ZnO). On the polar Zn-terminated ZnO(0001) surface, Cu becomes negatively charged, which causes it to attract positively charged subsurface defects and to wet the ZnO(0001) surface at elevated temperatures. When a Cu cluster on a ZnO surface becomes positively charged, this happens because it donates an electron to the ZnO conduction band. Hence, it is necessary to use a method which describes the ZnO band gap correctly, and we show that a hybrid density functional, which includes a fraction of Hartree-Fock exchange, fulfills this requirement. When the ZnO conduction band becomes populated by electrons from Cu, band-filling occurs, which affects the adsorption energy. The band-filling correction is presented as a means to extrapolate the calculated adsorption energy under periodic boundary conditions to the zero coverage (isolated adsorbate, infinite supercell) limit. A part of this thesis concerns the parameterization of the computationally very efficient SCC-DFTB method (density functional based tight binding with self-consistent charges), in a multi-scale modeling approach. Our findings suggest that the SCC-DFTB method satisfactorily describes the interaction between ZnO surfaces and water, as well as the stabilities of different surface reconstructions (such as triangularly and hexagonally shaped pits) at the polar ZnO(0001) and ZnO(000-1) surfaces.

Thesis (M.S.)--University of Michigan, 1976.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xiv, 215 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 143-147).

Thesis (M.S.)--University of Michigan, 2003. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1976.

We prove two new results about 0-1-fillings of skew diagrams avoiding long increasing and decreasing chains. In the first half of the thesis, we show that for a large class of skew diagrams, there is a bijection between sparse fillings avoiding an increasing chain of fixed length and sparse fillings avoiding a decreas- ing chain of the same length. In the second half, we extend a known inequality between the number of sparse 0-1-fillings of skew diagrams avoiding an increasing chain of length 2 and a decreasing chain of length 2 to all 0-1-fillings. 1

Foram avaliadas algumas propriedades físico-químicas, como o pH, liberação de íons cálcio, tempo de presa, solubilidade e radiopacidade de 3 cimentos a base do agregado de trióxido mineral, clínquer do cimento Portland e um epóxico experimental. Foram avaliados os cimentos MTA Angelus branco, MTA Bio, cimentos experimentais, MTA fotopolimerizável e Sealepox RP e o Clínquer de cimento Portland acrescido de 20% de óxido de bismuto e 5% de sulfato de cálcio. Para as avaliações do pH e da liberação de íons cálcio foram utilizados tubos de polietileno com 1,0 mm de diâmetro interno e 10,0 mm de comprimento, com apenas uma das extremidades aberta. Esses tubos foram preenchidos com os cimentos e imediatamente imersos em tubos de ensaio contendo 10 mL de água deionizada, onde permaneceram durante todo o período experimental. Realizaram-se avaliações nos períodos de 3, 24, 72 e 168 horas, sempre se renovando a água deionizada ao final de cada período. Os ensaios de tempo de presa, solubilidade e radiopacidade, foram realizados conforme a norma #57 da ADA. Em relação ao tempo de presa, também foi utilizada a agulha de Gilmore de 453,6 g, para a presa final, conforme recomenda a norma #C266-03 da ASTM. Os resultados demonstraram que todos os cimentos apresentaram pH alcalino e liberaram íons cálcio em todos os períodos, com tendência de redução nos períodos finais. Quanto aos tempos de presa, os cimentos MTA Angelus branco e o cimento experimental MTA Bio apresentaram os menores tempos. Já o Clínquer apresentou valores intermediários, e o Sealepox RP, apresentou os tempos mais longos. O cimento MTA fotopolimerizável, por suas características próprias, não foi submetido a esse teste. Em relação ao ensaio de solubilidade, o cimento que mais se aproximou das recomendações da ADA, foi o Sealepox RP, com valores próximos a 1%, enquanto que os cimentos MTA Angelus branco, MTA Bio e o Clínquer acrescido ao radiopacificador e sulfato de cálcio apresentaram valores maiores. O MTA fotopolimerizável apresentou valores menores. Em relação à radiopacidade, a maioria dos cimentos estudados apresentou valores superiores à da dentina, com resultados semelhantes entre si, com exceção do MTA fotopolimerizável, que apresentou valor próximo ao da dentina. / Some properties had been evaluated physicochemical, such as pH, release of calcium ions, setting time, solubility and radiopacity of 3 retrograde filling the base of the aggregate of mineral trioxide, to clínquer of the Portland cement and an experimental epoxy sealer. Experimental cements MTA white Angelus, MTA Bio, light-curing MTA and Sealepox RP and the Clínquer of cement Portland increased of 20% of bismuth oxide and 5% of calcium sulphate had been evaluated. For the evaluations of pH and the release of calcium ions had been used polyethylene pipes with 1,0 mm of internal diameter and 10,0 mm of length, with only one of the extremities open. These pipes had been filled with cements and immediately immersed in pipes of 10 assay I contend mL of distilled water, where they had remained all during the experimental period. Evaluations in the periods of 3, 24, 72 and 168 hours, always if renewing the distilled water to the end of each period. The assays of setting time, solubility and radiopacity, had been carried through in agreement the norm #57 of the ADA. In relation to the setting time, also g was used the needle of Gilmore of 453,6, for the final canine tooth, as it recommends to the norm #C266-03 of the ASTM. The results had demonstrated that all the cements had presented pH alkaline and had liberated calcium ions in all the periods, with trend of reduction in the final periods. How much to the setting time, cements MTA white Angelus and experimental cement MTA Bio had presented the lesser times. Already the Clínquer presented intermediate values, and Sealepox RP, presented the times longest. Light-curing cement MTA, by its proper characteristics, was not submitted to this test. In relation to the solubility assay, the cement that more was come close to the recommendations of the ADA, was Sealepox RP, with next values 1%, whereas cements MTA white Angelus, MTA Bio and the Clínquer increased to the bismuth oxide and calcium sulphate had presented bigger values. The light-curing MTA presented less resulted . In relation to the radiopacity, the majority of studied cements presented more values to the one of the dentine, with similar results between itself, exception of the light-curing MTA, that presented value next to the one to the dentine.