Using x-ray powder diffraction as a cost effective tool in cement industry

Rietveld Analysis of cement diffraction patterns have been used to determined the composition of cement since John Taylor\u27s pioneering work in the 1990\u27s. Since then many workers have used this techniques to analyse cement and supplementary cementitious materials and their hydration products, both for research and production control purposes. Nevertheless there are a number of factors, including the amorphous content of the cement and relative proportion of mineral polymorphs present in the initial clinker, whose impact on analysis are still not completely understood. X-ray powder diffraction beamlines from the Brazilian Synchrotron Light Laboratory (LNLS) and the Australian Synchrotron, which produce more intensity and better resolution than normal x-ray diffraction sources, were used to investigate cement diffraction patterns and the hydration products of a range of cement pastes cured for up to 28 days. This study highlights the information that can be obtained from X-ray diffraction analysis for controlling and optimizing cement production and concrete durability.<br /

Características morfogênicas e estruturais do capim-tanzânia submetido a doses de fósforo e nitrogênio Morphogenetic and structural characteristics of tanzaniagrass submited to phosphorus and nitrogen fertilization

O experimento foi realizado em casa de vegetação, no período de maio a agosto de 2005, com o objetivo de avaliar o efeito da adubação fosfatada e nitrogenada sobre as características morfogênicas e estruturais do capim-tanzânia. As avaliações morfogênicas englobaram as taxas de aparecimento e alongamento de folhas e a taxa de alongamento de colmo. As avaliações estruturais foram o número total de folhas e número de folhas verdes por perfilho, número de perfilhos da planta e comprimento final da folha. Foi utilizado delineamento inteiramente casualizado em esquema fatorial 4 x 2, sendo quatro doses de fósforo (0, 50, 100 e 150 kg/ha de P2O5) e duas doses de nitrogênio (0 e 100 kg/ha de N) com quatro repetições. Foram utilizados vasos com capacidade de 6,3 litros cada, que, após desbaste, permaneceram com quatro plantas por vaso. As doses de N e P foram determinantes para as taxas de alongamento de folhas e alongamento de colmo, o número de perfilhos por planta e número de folhas verdes por perfilho. O suprimento de nitrogênio teve efeito positivo sobre a taxa de aparecimento de folhas, o número total de folhas e o comprimento final da folha do capim-tanzânia. A maioria das variáveis estudadas foi influenciada pela aplicação de fósforo, quando associada à aplicação do nitrogênio.<br>The experiment was accomplished in a greenhouse from May to August of 2005, with the objective of to evaluate the effect of phosphorus and nitrogen fertilization on morphogenetic and structural characteristicas of Tanzania grass. The morphogenetic evaluations included leaf appearance, leaf elongation rate, and stem elongation rate. The structural evaluations measurements were: number of leaves, number of green leaves, number of tillers per plant, and final leaf length. It was used a complete randomized experimental design in 4 x 2 factorial scheme, being four phosphorus doses (0, 50, 100, and 150 kg of P2O5/ha) and two doses of nitrogen (0 and 100 kg of N/ha), with four replicates. It was utilized pots with 6.3 liters capacity each, leaving four plants per pot after staging. The N and P combination affected leaf elongation rate, stem elongation rate, number of tillers per plant, and number of green leaves per tillers. Nitrogen supply had a positive effect on leaf appearance rate, number of leaves, and final leaf length of tanzaniagrass. The majority of the studied variables were affected by the use of phosphorus when associated to N fertilization