Growth of Acidithiobacillus thiooxidans Biofilm on Glass, Concrete and Stoneware

Biofilms formed by various microorganisms are often responsible for microbiologically induced corrosion of materials exposed to moisture. Many bacteria strains may form biofilms on different mineral materials including concrete and stoneware. Among them, the sulfur-oxidizing bacteria of Acidithiobacillus genus, especially of A. thiooxidans species play an essential role in these materials' destruction. In the present study we observed comparable intensity of A. thiooxidans growth on concrete and glass, and slower biofilm formation on stoneware. Prolongation of incubation time caused an increase in biomass of A. thiooxidans biofilm formed on glass and stoneware. Amongst the investigated mineral materials, the concrete proved to be the most susceptible to deterioration by A. thiooxidans bacteria.

Investigation of Luminescent Poly(propylene imine) Dendrimer

Luminescence phenomenon from NH2-terminated third generation poly(propylene imine) dendrimers in water was investigated. Two excitation bands (340 and 370 nm) and corresponding emission bands (∼400 and ∼450 nm, respectively) were detected. Emission bands were intensified with time, heating and air-bubbling and converged at certain intensities, where the ∼400 nm band was red-shifted. The initially weak emission band at ∼450 nm in an alkaline solution was intensified up to the comparable intensity to the strongest emission band at ∼400 nm in an acidic solution, after long time. While 1H NMR spectra depended on pH owing to the protonation of amine, those were slightly affected by the time, heating and air-bubbling. However, no new 1H NMR signals appeared even after long time, indicating no finding of chemical structure change of dendrimer. This suggests that the luminescent property should result from any interaction of amine with oxygen but not the chemical reaction.

Partial melting of metapelites in the Gagnon terrane below the high-pressure belt in the Manicouagan area (Grenville Province): pressure–temperature (P–T) and U–Pb age constraints and implications

Metapelites of the parautochthonous Gagnon terrane at the footwall of the high-pressure (high-P) belt in the Manicouagan area (central Grenville Province) preserve an impressive textural record of partial melting reactions, mainly in polymineralic inclusions within garnet. The dominant textures were developed within the pressure–temperature (P–T) field of the continuous dehydration melting reaction biotite + kyanite (or sillimanite) + plagioclase + quartz = garnet + K-feldspar + melt, with sillimanite instead of kyanite in the southern part of the footwall. Inferred P–T paths have a hair-pin form in the range of 750–850 °C and 1000–1500 MPa for the kyanite-bearing rocks. Monazite crystallization ages are consistently late Grenvillian, either 995 or 985 Ma, and one sample contains monazite of both ages. Two of these samples also contain inherited monazite with ages of 1738 ± 5 and 1719 ± 30 Ma, indicative of an earlier metamorphic event. Tonalite and diorite from the same area yield Archean zircon crystallization ages and titanite ages of 961 ± 3 and 956 ± 4 Ma, the youngest in the Manicouagan region. The late Grenvillian metamorphism was of comparable intensity but ~50 Ma younger than in the overlying high-P belt in this area and therefore seems to be unrelated to the emplacement of the latter over the Parautochthonous Belt, as previously suggested. Rather, this younger metamorphism suggests a reactivation of the footwall by underthrusting of the Gagnon terrane during the waning stages of convergence, and a link with a major coeval post-tectonic thermal event farther south in the hinterland.

HIGH-ORDER DIFFRACTION IN PHOTOREFRACTIVE SBN:Ce DUE TO NON-SINUSOIDAL GRATINGS FORMED BY BEAMS OF COMPARABLE INTENSITY

We have observed multiple-order diffraction from photorefractive gratings formed by two input beams of comparable intensity that interfere in a single crystal of SBN:Ce. High-order diffraction occurs both in the direction of two-beam coupling gain and in the opposite direction. These results are in good agreement with the predictions of a theoretical model that interprets high-order diffraction as a form of Raman-Nath scattering from a highly anharmonic diffraction grating that is formed by a light intensity distribution having a large depth of modulation.

Building damage in Westport

The earthquake of 24 May 1968, was the second of damaging intensity to be experienced in Westport recently. The earlier (1962) quake was of smaller magnitude; but centred, as it was, at Westport it was probably felt with comparable intensity there. Restoration of widespread damage it caused undoubtedly reduced the extent of damage from the 1968 earthquake. Nevertheless the survey after the Inangahua earthquake showed clearly that some of the "remedial work” that followed the 1962 earthquake was simply patching up of surfaces, with no structural significance. Not surprisingly the 1962 wounds so "treated" appeared again in 1968.

ALLUVIAL CONE CONSTRUCTION BY ALPINE MUDFLOW IN A HUMID TEMPERATE REGION

In a humid, temperate area of central-western Alberta, a mudflow occurred along Hell's Creek, a short tributary of the Smoky River in July, 1962, during a heavy rainstorm. Flows had not occurred during the previous 3 years, even though rains of comparable intensity had fallen. The source area is a steep-sided rock amphitheater, cut in deformed shales and siltstones, and almost devoid of vegetation. The mud moved over a mile in a narrow stream valley and spread across the lower part of an alluvial cone. The exposed lithology of the cone suggests that mudflow is the principal agent in construction of this and other cones of the region. Deposition of the cone has diverted the course of a large river.