[en] This study presents the levels of the chloroform formation during water disinfiction treatment by chlorination with the subsequent formation of by-products like trihalomethanes (THMs) are formed. These THMs in drinking water are found in the form of chloroform, bromodichloromethane, Chlorodibromomethane and bromoform. Out of these four compounds chloroform is the major culprit and Contribute 9.0% of the total THMs concentration (I). Therefore the present work was focused on the Estimation of levels of chloroform in the drinking water samples of Karachi city (Pakistan) by using Bootstrapping statistical technique with regards to the average cancer risk in the community. (author)

[en] With the extensive increase in the utilization of energy resources in the modern era, the need of energy extraction from various resources has pronounced in recent years. Thus comprehensive efforts have been made around the globe in the technological development of turbo machines where means of energy extraction is energized fluids. This development led the eviation industry to power boost due to better performing engines. Meanwhile, the structural conformability requirements relative to the functional requirements have also increased with the advent of newer, better performing materials. Thus there is a need to study the material behavior and its usage with the idea of selecting the best possible material for its application. In this work a gas turbine blade of a small turbofan engine, where geometry and aerodynamic data was available, was analyzed for its structural behavior in the proposed mission envelope, where the engine turbine is subjected to high thermal, inertial and aerodynamic loads. FE linear stress analysis was carried out on the turbine blade. The results revealed the upper limit of UTS for the blade. Based on the limiting factor, high performance alloys were selected from the literature. The two most recommended alloy categories for gas turbine blades are NIMONIC and INCONEL from where total of 21 types of INCONEL alloys and 12 of NIMONIC alloys, available on on commercial bases, were analyzed individually to meet the INCONEL alloys for further analysis. On the basis of stress-strain behavior of finalized alloys, the FE restriction of UFOS of 1.33 and yield strength. Final selection is made keeping in view other factors like manufacturability and workability in due consideration. (author)

[en] Building materials are considered as one of the main sources of internal and external hazards inside in building. External hazards are due to gamma rays emitted from Ra-226, Th-232 and K-40. For the estimation of external and internal hazards from the construction material, the values of Ra-226, Th-232 and K-40 concentrations in the building material and rate of radon exhalation from construction material are of great importance. The exhalation rate is base done the detection of alpha-particle inside the closed container. Measurements of concentration of Ra-226, Th-232 and K-40 were done, by gamma ray spectrometer. (author)

[en] Building materials are considered as one of the main sources of internal and external hazards inside in building. Almost all types of internal hazards are concerned with alpha-decay and its short lived decay products. External hazards are due to gamma-rays emitted from Ra-226, Th-232 and K-40. For the estimation of external and internal hazards from the construction material, the values of Ra-226, Th-232 and K-40 concentrations in the building material and rate of radon exhalation from construction materials are of great importance. The exhalation rate is base on the detection of alpha particles inside the closed container. Measurements of concentration of Ra-226, Th-232 and K-40 were done by gamma-ray spectrometer. (author)

[en] The indoor radon concentration is due to the diffusion of radon from the building materials. Its variation is generally the reflection of two factors, ventilation and exhalation rate from the building materials. In our measurements radon concentration in different portions of houses varies from 31.05 Bq m/sup -3/ to 61.24 Bq m /sup -3/. This variation is due to different ventilation conditions. Sand with exhalation rate of 2.84 Bq m /sup -2/h/sup -1/ is considered as the major source of radon concentration inside the houses, while stone-crush exhaling with 1.49 Bq m/sup -2/h/sup -1/ contributes the least for the build-up of radon in the houses, monitored. (author)

[en] Radon anomalies prior to an earthquake have been considered as an important precursor for earthquake prediction. The study of radon anomalies for earthquake prediction, however, require long term continuous monitoring. The solid state nuclear track detectors are well suite for such study. The radon concentration variations, prior to an earthquake, have been observed at four different stations by us with variable detector exposure time and holes, having different depths augured for radon monitoring. A positive correlation has been observed between radon build up and occurrence of an earthquake at many instances even when the distances between the radon monitoring stations and earthquake epicenters was as far as hundreds of kilometers. It has further been observed that radon signal for the arrival of an earthquake is received earlier and more enhanced in deeper holes in which radon monitoring device (steel tube containing CN-85 plastic track detector) is placed. (author)