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Coal mine fire is a common phenomenon in Indian coalfields and great concerned on safety of the person engaged in mining operations. In opencast coal mine, particularly where the extraction of previously developed coal pillars has been carried out by opencast mining method, chances of spontaneous fire became more frequent and complicated. In such prevailing situations deep holes charging and blasting operation in hot strata may create every possibility to premature detonation of explosives, which leads to fatalities. Henceforth, it is imperative to use appropriate methodology to combat the fires and make it possible for wining of coal safely. This paper highlighted a methodology adopted for safe and effective management of fire by using two different chemical additives admixed with water to bring down temperature under safe workable limit in short duration of time and also make it suitable for charging and blasting operation in hot deep drill holes. On the basis of the magnitude of fires 0.5 to1.0% concentrations of MgCl2 and CaCl2 mixed with water were applied for cooling of high temperature fire in coal bench, overburden as well as hot blast holes with encouraging results in supressing of the flames and rapid cooling of hot strata. [ABSTRACT FROM AUTHOR]

Aims: To determine the results of pars plana vitrectomy (PPV) and silicone oil infusion (SOI) in severe proliferative diabetic retinopathy (PDR). Methods: The records of 23 eyes (21 patients: 12 [...]

Konkan Railway has many unstable slopes along the 741 km long route from Roha to Thokur in the states of Maharashtra, Goa and Karnataka in India. Frequent cases of boulder fall, slope failure and landslide used to occur on the track during the rainy season. Such cases have resulted in several severe train accidents, traffic interruptions, loss of lives and assets. Hence the Konkan Railway Corporation deployed several geotechnical measures such as wire-netting, retaining wall, rock bolting and shotcreting for stability enhancement. However, none of these measures proved effective and accidents continued. Finally, the Konkan Railway Corporation decided to redesign the cut-slopes using blasting. Excavation of hard rock for its removal without damaging the existing track (2- 3 m away from the slope) and disrupting the traffic, was a daunting task. An unplanned blast would have resulted in the closure of the route for hours. The present study explains the method in which entire cutting was redesigned by formation of 5 to 2 m wide berms at an interval of 6 m bench height from rail track level using novel direction controlled blasting technique. Further, stability of the cut-slope, before and after exacavation, has been determined using kinematic analysis and 3D numerical modelling. Similar technique can be adopted to widen or stabilize an active transportation route in hills. [ABSTRACT FROM AUTHOR]

Specimens of the amorphous Fe[sub 72]Cu[sub 1]Nb[sub 4.5]Si[sub 13.5]B[sub 9] alloy have been nanocrystallized by furnace (FA) and current (CA) annealing and analyzed by simultaneous small-angle (SAXS) and wide-angle (WAXS) x-ray scattering using the beam-line 5.2L at Elettra Synchrotron Source, Trieste. The analysis has been carried out also dynamically on untreated samples current heated in situ. Significant differences in the SAXS regime have been observed between the FA and CA samples having the same amount of nanocrystallization as determined from previous WAXS and Mo¨ssbauer measurements. These differences can be attributed to a lower contrast of the nanocrystallites in the CA samples as compared to FA samples. The Mo¨ssbauer spectra show that in FA and CA samples the nanocrystalline grains consist of a nonstoichiometric partially disordered Fe[sub 3]Si phase, and indicate the presence of boron atoms in the nanocrystals of CA samples. This is in agreement with the lower contrast found by SAXS and implies a lower segregation of boron atoms and/or of borides at the boundaries of nanocrystallites of CA samples, accounting for their lower brittleness. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]