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Heavy metal pollution in wastewater has always been a serious environmental problem because heavy metals are not biodegradable and can be accumulated in living tissues. Copper is widely used in various important industrial applications. The increasing level of heavy metals in the aquatic system due to incomplete treatment of industrial wastewater by existing conventional methods is of environmental concern. Therefore, there has been an increasing interest in the possibility of using biological treatments. It is important to evaluate the performance of biomass with actual industrial effluent to ensure its field applicability. Hence the experiments were conducted with actual industrial effluents collected from Effluent Treatment Plant (ETP) and tannery industry.

This investigation describes and analyses the experimental results pertinent to the penetration of steel plates of varying hardness in the range HV295–HV520 and of thickness 20 and 80 mm by ogive-shaped 20-mm-diameter projectiles over the velocity range 300–800 m s −1 . All the tests were carried out at normal impact angle, i.e. zero obliquity. The experimental results presented include the variation of depth of penetration, crater volume, lip height, bulge height and diameter, plugged length and diameter and specific energy absorption capacity with impact velocity for tests on each plate of a given hardness and thickness. Selected data and observations relating to the plastic zone size and shape surrounding the penetrating projectile, incidence and extent of adiabatic shear band (ASB) formation and plate spalling have also been presented. These experimental data have been interpreted in terms of the appropriate penetration mechanisms like ductile hole formation, bulging followed by star cracking, ASB-induced shear plugging, etc., and also by making use of the fact that the projectile undergoes substantial deformation when penetrating the harder plates (HV450 and HV520). It is also demonstrated that the resistance to penetration and hence the mechanism of penetration is very much dependent on whether the penetration occurs under plane strain or plane stress conditions. For example, ASB-induced plugging occurs only under plane stress conditions while projectile deformation is dominant only under plane strain conditions even in harder plates.

Summary This investigation describes and analyses the experimental results pertinent to the penetration of steel plates of 20, 40 and 80 mm thickness by non-deforming, ogive shaped 20 mm diameter projectiles over the velocity range 300–800 m/s. All the tests were carried out at normal impact angle, i.e. zero obliquity. The experimental results presented include the variation of the depth of penetration, crater volume, lip height, bulge height and diameter and specific energy absorption capacity with impact velocity in 20, 40 and 80 mm plates. Selected data on the size and shape of the plastic zone in the plate surrounding the penetrating projectile have also been obtained. These experimental data have been rationalized on the basis of energy based models: one for constrained, plane strain penetration and the other for bulging characterized by unconstrained, plane stress plastic flow.

Random hopping processes between discrete sites along a finite open chain or around a closed finite loop are examined. Closed form formulae are prescribed for the dependence of the ESR (electron spin resonance) line shape on the chain length and hopping rate. Significant differences between the closed loop and open chain are demonstrated. Deviation at short time from the results of diffusion in a continuum is presented.