An investigation is made into the effects of water jet pressure, nozzle diameter, traverse speed of the nozzle over the rock surface and the number of times the jet passes over the same area on the penetration of a water jet into Indiana limestone. The effectiveness of the cut is judged on the depth of cut established and the specific energy of rock removal. Pressure is varied in the range from...

The family Streptaxidae in Laos is revised. Twelve species are known, mainly from limestone areas, in the genera Discartemon Pfeiffer, 1856, Perrottetia Kobelt, 1905, Haploptychius Möllendorff, 1906, and Indoartemon Forcart, 1946. Three new species, Perrottetia unidentata sp. n. and Perrottetia megadentata sp. n. from northern and central Laos, and Indoartemon diodonta sp. n. from central Laos,...

Soil and rock surfaces support microbial communities involved in mineral weathering processes. Using selective isolation, fungi were obtained from limestone surfaces of Mayan monuments in the semi-arid climate at Yucatan, Mexico. A total of 101 isolates representing 53 different taxa were studied. Common fungi such as Fusarium, Pestalotiopsis, Trichoderma, and Penicillium were associated with s...

a simple, rapid and economic procedure was presented to remove lead(ii) from aqueous solution under the optimized conditions. it is based on the sorption of pb2+ ions from aqueous solutions onto limestone fines (ls), which is an inexpensive and widespread over the globe, followed by flotation with oleic acid (hol) surfactant. the different parameters (namely: solution ph, sorbent, surfactant an...

This paper aims at investigating the influence of partial replacement of Portland cement with ultrafine fillers compared to limestone powder on the durability and mechanical characteristics of concrete. For this purpose, ultrafine calcium carbonate materials with different specific surface areas of 9.7 and 15.1 m2/g and limestone powder (0.72 m2/g) were used. The results indicate that the ultra...