NOPR Collection:

On the instability problems in South Hlimen landslide, Mizoram

2014-11-05T09:42:03Z

Title: On the instability problems in South Hlimen landslide, Mizoram Authors: Kumar, Shiva; Singh, T N; Sawmliana, C Abstract: South Hlimen Quarry is one of the best quality sand stone quarries in the state of Mizoram. The problems of instability at the quarry site are due to the blocky nature of such gaint blocks are because of the intersection of the bedding and joint planes. On the 10^th August, 1992, the disastrous landslide took place as a result of planer and toppling failure of the blocky sandstones. The field observations indicated that such incident can be minimized in future, if a detail study can be conducted, recorded and classified as per International Society for Rock Mechanics (ISRM). In order to meet the increasing demand of sandstone production which arises with rapid urbanization of Aizawl, a more mechanized and systematic quarrying will be required, instead of a haphazard excavation from the foothill. It will help to protect the hiIIslopes as well as surrounding environments. Page(s): 78-80

An integral formulation for mass transfer of a reactive species in a channel from a moving surface with blowing

1997-04-01T00:00:00Z

Title: An integral formulation for mass transfer of a reactive species in a channel from a moving surface with blowing Authors: De, Sirshendu; Dhar, Joydip Abstract: An integral method for mass transfer analysis of a reactive species in laminar boundary layer in a channel from a moving surface with blowing is developed. The effects of relevant process parameters, e.g., Reynolds number, reaction rate, reaction order, Schmidt number and blowing, on mass transfer have been studied. When reaction rate is dominant compared to convection, several asymptotic solutions are formulated for high and low Schmidt number. The model presented in this paper provides a simplistic mathematical description of a complex situation encountered in several industrial applications like, post processing of extrusion in polymer processing rolling and moulding in metallurgical processes and in electrochemistry. Page(s): 71-77

Optimisation of rebetatising time and temperature for lowering martensitic transformation temperature in Cu- Zn-4% A1 shape memory alloy

1997-04-01T00:00:00Z

Title: Optimisation of rebetatising time and temperature for lowering martensitic transformation temperature in Cu- Zn-4% A1 shape memory alloy Authors: Prakash, Kuldip; Harchekar, V R Abstract: Cu-Zn-A1 shape memory alloy (SMA) is a new class of smart engineering materials which can be incorporated in varieties of heat sensitive devices. Its martensitic transformation temperature is very sensitive to alloy composition which can be raised to some extent by incorporating a bias spring or by dezincification. However, lowering this temperature, once obtained, poses problems. The present paper reports that martensitic transformation temperature could also be lowered to some extent (~ 20°C) without much adverse effect on the shape memory response in Cu-Zn-A1 (4 wt% A1) shape memory alloys, by rebetatising the material at lower temperature. Page(s): 67-70

Experimental investigations of pick-rock interface temperature in drag-pick cutting

1997-04-01T00:00:00Z

Title: Experimental investigations of pick-rock interface temperature in drag-pick cutting Authors: Loui, P John; Rao, K U M Abstract: Temperature developed during drag-pick cutting has been measured in laboratory, on a single pick orthogonal cutting tool. Other cutting responses such as cutting force, wear rate of picks, and depth of cut were also measured. All these measurements were carried out for different machining parameters such as thrust and cutting speed on five rock type’s viz., sandstone two varieties of granites and two varieties of limestones. For softer rocks (limestones), the maximum temperature ranged between 236 and 566°C whereas in harder rocks (granites) temperatures as high as 920°C were also recorded. This rise in temperature may be due to the frictional heat produced by the rubbing of the rake and flank faces of the drag cutter against the rock surface. The deleterious effect of high temperature, indicated by wear rate, has also been studied. Page(s): 63-66