The Accelerated bridge construction (ABC) techniques are gaining popularity among the departments of transportation (DOTs) due to their reductions of on-site construction time and traffic delays. One ABC technique that utilizes precast deck panels has demonstrated some advantages over normal cast-in-place construction, but has also demonstrated some serviceability issues such as cracks and water leakage to the transverse joints. Some of these problems are addressed by applying longitudinal prestressing. This thesis evaluates the service and ultimate capacities in both flexure and shear, of the finite element models of the post-tensioned system currently used by Utah Department of Transportation (UDOT) and a proposed curved-bolt system to confirm the experimental results. The panels were built and tested under negative moment in order to investigate a known problem, namely, tension in the deck concrete. Shear tests were performed on specimens with geometry designed to investigate the effects of high shear across the joint. The curved-bolt connection not only provides the necessary compressive stress across the transverse joint but also makes future replacement of a single deck panel possible without replacing the entire deck. Load-deflection, shear-deflection curves were obtained using the experimental tests and were used to compare with the values obtained from finite element analysis. In flexure, the ultimate load predicted by the finite element model was lower than the experimental ultimate load by 1% for the post-tensioned connection and 3% for the curved-bolt connection. The shear models predicted the ultimate shear reached, within 5% of the experimental values. The cracking pattern also matched closely. The yield and cracking moment of the curved-bolt connection predicted by the finite element model were lower by 13% and 2%, respectively, compared to the post-tensioned connection in flexure.

In this thesis, we explore detailed voxel scene compression methods and editing thereof with the goal to design an interactive voxel viewer/editor, for e.g. a 3D printing appli- cation. We present state-of-the-art GPU compatible data structures and compare them. On top of the chosen data structure, we build standard editing tools known from 2D, capable of changing voxel color in real-time even on lower end machines. 1

The aim of this study was to arrive at a fundamental understanding of kimberlite weathering and of factors which affect the rate and extent of weathering. Weathering was evaluated by measuring the change in size distribution after immersing crushed kimberlite in solutions of various compositions. Reproducibility of the measurements was found to be good, with the cumulative mass passing a given size differing by 7% or less, as tested for various weathering conditions. Kimberlite mineralogy, specifically the swelling clay content, was found to play a central role: kimberlite ores containing no swelling clay were not prone to weathering under any of the conditions tested. The cation exchange capacity (CEC) correlates well with the swelling clay content and with the weathering behaviour. The cation exchange capacity may be used in conjunction with the swelling clay content, as a predictor of possible kimberlite behaviour; however, given the relative complexity and cost of measuring swelling clay content (by X-ray diffraction), the CEC is the preferred parameter for practical use. Cations in the weathering solution have a strong effect on kimberlite weathering; the strength of the effect followed the series Cu2+ > Li+ > Fe2+ > Ca2+ > Fe3+ > Mg2+, whereas K+ and NH4+ stabilised the kimberlite somewhat against weathering. This sequence was in reasonable correlation with the ionic potential (ratio of valency to ionic radius), but with exceptionally strong weathering effects of Cu2+, and (to a lesser extent) of Li+ and Fe2+. The strong effect of the latter group of cations may be related to their tendency to adsorb onto other crystal sites in addition to the interlayer – the associated change in surface energy can change the fracture behaviour of the kimberlite. Measurement of the layer spacing of the swelling clay (by X-ray diffraction) showed no correlation between the weathering effect of a cation and the associated thickness of the interlayer. For solutions of cupric ions, the identity of the anion (chloride or sulphate) has little effect on weathering. The size of the crushed kimberlite ore similarly has little effect on the relative extent of size degradation by weathering. The concentration of cupric ions affects weathering, as does the weathering time – although 85% of the weathering caused by 30 days' exposure was found to occur within the first 24 hours. Increasing the temperature to 40°C (in a magnesium chloride solution) also increased weathering strongly. The kinetics of exchange of cuprous and potassium ions was measured (for two different kimberlites); the apparent reaction order (with respect to the concentration of exchanging cations in solution) varied between 1 and 3.5, and exchange of potassium was more rapid. This work has practical implications for in-plant processing of kimberlite, possible alternative kimberlite processing routes which eliminate one or more crushing steps, and for the stability of mine tunnels which pass through kimberlite. / Thesis (PhD (Metallurgical Engineering))--University of Pretoria, 2006. / Materials Science and Metallurgical Engineering / PhD / unrestricted

This paper gives a brief overview on the published and accepted standards and methods for colour photography and print lightfastness measuring and evaluating. A comparison of selected valid standards and evaluation suggestions has been made. Sample sets was produced by various photographic processes and printing techniques. Identical sample sets were used in both long-term and accelerated ageing experiment. In this thesis, the degradation speed is expressed as a formal rate constant, which was calculated from the dependence of normalized gamut volume on the exposure dose. Photographs and prints were compared on calculated lifetime basis. A failure of reciprocity law was observed, which indicates a lower credibility of estimated lifetime predictions based on accelerated ageing.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第19340号 / 情博第592号 / 新制||情||103(附属図書館) / 32342 / 京都大学大学院情報学研究科社会情報学専攻 / (主査)教授 多々納 裕一, 教授 矢守 克也, 教授 守屋 和幸 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DGAM

Steel corrosion is one of the major distress mechanisms that causes the deterioration of reinforced concrete structures around the world. It is an electrochemical reaction between the reinforcing steel and the surrounding concrete that produces a mass loss of the metal. Through the process of corrosion in reinforced concrete, iron ions get oxidized to form corrosion products (CP). Although multiple experiments and studies have been developed to understand the rheological behavior of corrosion products, this topic stays inconclusive. This work aims to characterize corrosion products at micro-scale in order to trace the progress of the formation of rust, to determine its nature and to analyse its rheological behavior in reinforced concrete. An experimental procedure to produce CP in the laboratory is also presented in this research. In addition, material characterization methods have been used to identify the iron oxide phases present in CP, determine their viscosity and rheological behavior and to study how CP flows in a porous media. In order to identify the different stages in the corrosion process, the CP was analysed at 2, 4, 6 and 8 weeks. The experiments identified four phases of iron oxide for each period. Furthermore, it was found that CP behaves as a shear-thinning slurry and as a result, its viscosity decreases with the applied shear rate. In addition, the damage caused by CP on concrete depends on the w/c ratio of the concrete mix and the exposure time to a corroding environment. The rebar mass loss results show that CP is formed in layers around the rebar, and the flow of each CP layer can differ.

Studies of aging processes were conducted on pyrolysis oils produced from pine and cottonwood biomass (clear wood, whole tree, bark and needles/leaves). Accelerated aging at 80 °C for up to 504 h was employed to investigate the short and long-term effects of feedstock, phase separation, char particulates, and solvent addition on pyrolysis oil properties. Feedstock containing forestry residue was found to increase water content of neat pyrolysis oil and the collection method (total vs. fractionated) affects all of the properties with the largest impact on viscosity and as produced molecular weight. Post-condensation liquid filtration did not prevent aging-related water content or molecular weight increases during aging but did retard aging reactions in pine clear wood and pine bark pyrolysis oils. Methanol addition retarded the aging reactions in pine needle fractionated pyrolysis oil; at 15 wt% phase separation was prevented and molecular weight increased 11 % after 504 h of aging.

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The purpose of this study was to explore the relationship between time spent on a computer managed integrated learning system entitled Accelerated Math and traditional mathematics instruction on achievement as measured by standardized achievement tests of elementary school students. The variables of ability level, special education, grade, socioeconomic status, gender, classroom teacher, school attended, and degree of implementation were also considered. The population consisted of 542 students who were sixth, seventh, and eighth graders during the 2003-2004 school year and took the TerraNova each year. Data were gathered that covered the three-year period beginning in 2001 and ending in 2004. A t test for independent samples, analysis of variance (ANOVA), and analysis of covariance (ANCOVA) were used to identify the relationship between variables. The researcher’s investigation of the relationship between Accelerated Math use and mathematics achievement might assist educators in planning for use of technology as a supplement to traditional instruction. The information gathered from this research might be beneficial to other school systems seeking information on the relationship between a computermanaged integrated learning system and math achievement. The findings in this study were mixed. The use of Accelerated Math was associated with no effects and negative effects depending on the degree of implementation. The findings indicated that there were measurable differences in the performance of students who received Accelerated Math compared to students who did not receive Accelerated Math. Students who did not receive Accelerated Math had higher overall scores than students participating in the intervention. The study indicated that gender, special education, and ability groups did not have a significant interaction with the intervention (participation in Accelerated Math). The research revealed that there was a socioeconomic status interaction intervention with proficiency scores. The study revealed that there was a significant intervention interaction with school, teacher, and grade. There was a significant interaction intervention for both proficiency and value-added scores for each of these three independent variables. In addition, the research revealed that the degree of implementation was a significant factor in students' achievement.

The purpose of this study was to examine the effects of dual-enrollment participation on students' postsecondary achievement as measured by various factors. The researcher explored an approach to learning that allows students to navigate the invisible barriers between high school and college. The population consisted of 901 students in a community college in northeast Tennessee during the fall of 2007 following high school graduation the previous academic year. Data gathered from dual-enrollment participants were compared to data of peers of comparable ability level who chose not to participate in the program. The major findings of the study included the following: dual-enrollment participants were (a) slightly more likely to enroll full time rather than part time, (b) significantly less likely to be enrolled in remedial and developmental courses, (c) no more likely to complete the fall semester, (d) slightly more likely to complete the spring semester, (e) more likely to showcase a slightly higher fall semester grade-point average (GPA), and (f) no more likely to have a higher spring semester GPA.