The possibilities of the classification of simulated observations in the GAIA photometric system are investigated. The data simulated by Barselona group [gaia.am.ub.es] from the BaSeL-2.2 and NextGen2 libraries of synthetic spectra are used. At first, the flux distribution curves of synthetic spectra for NextGen model atmospheres [ftp.hs.uni-hamburg.de] are compared with the observed flux distribution curves of stars of few spectral classes [Straižys V., Sviderskienė Z., 1972]. It was shown, that just the atmospheric models of hotter stars (Teff > 5000 °K) predict the observed energy distribution quite well. The observations in the GAIA photometric system simulated by Barcelona group are classified using the method of comparison of the color indices of standard and investigated stars. The observations of stars of two magnitudes (G=15 mag and G=18 mag) in the C1M photometric system are investigated in more detail. The analysis of the results shows that the classification is more definite when the bank of more solid standards is used. The errors of classification are smaller for the hotter (Teff > 10000 °K) and more luminous (G=15 mag) stars. The interstellar extinction AV is defined more precisely for hotter stars and the stars with larger AV value (3 ≤ AV ≤ 5). The computing time necessary to classify one star using the method of comparison of the color indices of standard and investigated stars is measured . The classification algorithm is written in PERL. The time... [to full text]

The research objective was to develop a new competitively priced, high strength macrosynthetic fiber for concrete reinforcement. Mechanical bond properties were examined through aligned and inclined pullout testing. Variables involved in optimizing these properties included materials, fiber cross section, and other changes made through manufacturing processes. In addition to extensive pullout testing, improvements to fiber properties were explored through tensile testing, creep testing, and fiber performance in concrete mixtures. Practical considerations were also made, such as manufacturing processes, cost, and workability. Properties of synthetic microfibers were also considered for use in engineered cementitious composites. Synthetic macrofibers containing PVDF demonstrated high bond strength in pullout testing. Fibers demonstrating the highest performance in FRC testing were those with additional mechanical anchorage such as fibrillation or embossment. EVA as an additive did not exhibit increased interfacial bond, but further research was recommended. Further research on deformed fibers containing PVDF was also recommended.

The purpose of this research was to determine uni-axial response of synthetic fibres required for structural design. The stress versus crack opening curves, required by RILEM for structural design of fibre reinforced concrete, were determined for each fibre type investigate and were used to compare the per fibre post-crack response, the pullout curves, and the flexural response. A study of the fibre distribution was conducted in order to determine the orientation factor required to predict the number of fibres expect in the tensile specimen crack face. The orientation factor, dosage, fibre geometry, and per fibre post-crack response were determined in order to predict the resulting tensile strength of a concrete mix. The tensile strength was compared to that of steel fibre currently being used in structural applications. The synthetic fibres tested only achieve a small percentage of their ultimate tensile strength; in order to produce synthetic fibres for structural applications, the bond strengths must be improved.

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In this project, three separate experiments were conducted to assess heavy metal removal from metal aqueous solutions and synthetic landfill leachate by adsorption using low-cost natural adsorbents. Fundamental batch investigations indicated that the 4.0-4.75 mm crushed mollusk shells and the Sphagnum peat moss were the best adsorbents for cadmium and nickel removal, respectively. Peat moss was also found to have the highest adsorption capacities for manganese and cobalt adsorption. The adsorption capacities of the peat moss and crushed mollusk shells used as natural adsorbents for the adsorption of cadmium and nickel from binary aqueous solutions in fixed-bed columns under continuous flow conditions were investigated. The life expectancy of each adsorbent in the fixed-bed columns was also assessed for different hydraulic loading rates. The flow rate of 1.5 mL/min (surface loading of 27.52 cm3/cm2•day) and bed depth of 15 cm were identified as the better operational conditions from the column testing. The results indicated that 47.9% and 42.7% cadmium and nickel removal efficiencies could obtained under these operational conditions, respectively. Finally, the peat moss and the crushed mollusk shells were packed in bench-scale down-flow fixed-bed columns to evaluate their adsorption capacities as natural low-cost adsorbents for the removal of heavy metals from aerated and non-aerated synthetic landfill leachate. The flow rate applied in this operation was 1.5 mL/min (surface loading of 27.52 cm3/cm2•day). Peat was found to have the best adsorption capacities in columns treating aerated synthetic leachate for cadmium (78.6%) and nickel (83.8%) removal efficiencies. / Thesis (Master, Civil Engineering) -- Queen's University, 2008-01-31 22:37:34.381

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