Coal Fly Ash Utilization: Low Temperature Sintering of Wall Tiles

We present here a study of the sintering of fly ash and its mixture with low alkali pyrophyllite in the presence of sodium hexa meta phosphate (SHMP), a complex activator of sintering, for the purpose of wall tile manufacturing. The sintering of fly ash with SHMP in the temperature range 925–1050 °C produces tiles with low impact strength; however, the incremental addition of low alkali pyrophyllite improves impact strength. The impact strength of composites with ⩾40% (w/w) pyrophyllite in the fly ash–pyrophyllite mix satisfies the acceptable limit (19.6 J/m) set by the Indian Standards Institute for wall tiles. Increasing the pyrophyllite content results in an increase in the apparent density of tiles, while shrinkage and water absorption decrease. The strength of fly ash tiles is attributed to the formation of a silicophosphate phase; in pyrophyllite rich tiles, it is attributed to the formation of a tridymite-structured T-AlPO4 phase. Scanning electron micrographs show that the reinforcing rod shaped T-AlPO4 crystals become more prominent as the pyrophyllite content increases in the sintered tiles

Regional brain metabolism in schizophrenia: The influence of antipsychotics

Background: Schizophrenia has been associated with a plethora of metabolic changes in the brain that vary with duration and type of psychoses. Additionally, it has been observed that antipsychotics can further alter cerebral glucose metabolism. These changes resulting from antipsychotics have been postulated to be reflective of the duration and mechanism of action of the medication. Aims: We aimed to examine the influence of antipsychotics on brain metabolism in individuals with schizophrenia in a naturalistic setting. Settings and Design: A cross-sectional study was carried out by the psychiatry department of a tertiary care hospital in collaboration with the Radiation Medicine Centre. Materials and Methods: Eighteen male patients with schizophrenia in different phases of treatment underwent an 18F-deoxyglucose positron emission tomography scan in a resting state 12 hours after the last dose of antipsychotic. Statistical Analysis: The types and duration of treatment were then compared with the regional glucose uptake in 14 predetermined regions of interest. The relative Uptake Values were further compared using SPSS 11.0. Results: An immediate increase followed by a decrease in cortical uptake was noted while the basal ganglia uptake remained high, albeit with a decreasing trend. Typical antipsychotics were associated with lower frontal cortical and higher basal ganglia and cerebellar uptake as compared to atypical antipsychotics. Conclusion: The differential influence of the type and duration of antipsychotic on glucose uptake suggests a possible trend towards long-term side effects with typical medications that were not noted on clinical examination. This however needs to be confirmed with larger, controlled studies