Sinha, Santanu2015-09-162023-10-262015-09-162023-10-262007ROLL NO.02612103http://172.17.1.107:4000/handle/123456789/150Supervisor: S. B. SantraA new site percolation model namely the directed spiral percolation (DSP) model is constructed imposing directional and rotational constraints simultaneously on the ordinary percolation model. the DSP model can be used to study the critical propcrties of disordered systems under crossed external bias fields. The bias fields could be of electric and magnetic in nature when the motion of charged particles are considered. In order ...enPHYSICSThesis