Junaid, Bushiri M; Wilson, E V; Vaidyan, V K(June , 2010)
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Abstract:
Urolithiasis is identified to be a major urological disorder affecting people all over the world irrespective of their age, sex and race. Urinary stone samples resected from the urinary bladders of two patients belonging to tropical region, Kollam District of Kerala State, India are investigated by using XRD,SEM, EDAX, TGA, DSC and FTIR to understand its chemical structure. Uric acid shows exothermic peak around 432°C is due to the decomposition with the evolution of CO and cracking of the remaining products. Results of analytical studies reveal that samples under investigation consist mainly in uric acid and hydrated uric acid. Hydrogen bonding exists in hydrated uric acid samples
Description:
Journal of Optoelectronics and Biomedical Materials Vol. 2, Issue 2, June 2010, p. 85 - 90
Deepa, Nair G; Alex, Fraaij; Adri, Klaassen A K; Arno, Kentgens P M(Elsevier, 2008)
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Abstract:
Various factors determine the applicability of rice husk ash (RHA) as a pozzolanic material. The amount and accessibility of reactive sites is
thought to be a key factor. A structural study of RHA samples in relation to their reactivity has been performed; Silica in RHA formed by burning
rice husk in a laboratory furnace under continuous supply of air have been characterized as a function of incineration temperature, time and
cooling regime. The characterization methods included chemical analyses, conductivity measurements, microscopic analysis, X-ray diffraction
(XRD) and 29Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR). In line with earlier observations, the analyses show that the
highest amounts of amorphous silica occur in samples burnt in the range of 500 °C–700 °C. The 29Si NMR data allow direct identification of the
reactive silanol sites in the RHA samples. De-convolution of the NMR spectra clearly shows that the quickly cooled RHA resulting from burning
rice husk for 12 h at 500 °C has the highest amount of silanol groups. This sample also induced the largest drop in conductivity when added to a
saturated calcium hydroxide solution giving an indication of its reactivity towards lime. Therefore, this RHA is the favorable sample to be used as
pozzolanic cement additive