Pikul Sarkar

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Hot-electron injection is widely used for accurate programming of on-chip floating-gate voltage and current references. The conventional programming approach involves adapting the duration and magnitude of the injection pulses based on a predictive model which is estimated by using measured data. However, varying the pulse-widths or amplitudes introduces(More)
The established model of the flashover of an insulator, whose surface is covered with a moist, conducting layer of pollution, envisages that it develops from the formation and bridging of a dry band by a partial-arc pre-discharge. This pre-discharge is assumed to possess arc characteristics, so that the electric field across the dry band will fall as the(More)
This paper describes a novel compressive self-powering technique that significantly extends the powering and sensing range of our previously reported piezo-floating-gate (PFG) sensors for applications in mechanical impact monitoring. At the core of the proposed technique is a nonlinear impedance circuit that dynamically loads the output of a piezoelectric(More)
Inclined-plane tests of silicone-rubber samples prepared with textured patterns of hemispherical protuberances are described. These are compared with the results obtained for conventional non-textured plane-surface samples of the same material. A remarkable improvement is achieved by such texturing: a material which normally fails the test is enabled to(More)
One of the major challenges in remotely powered sensors is that events being monitored can not be time-stamped due to the unavailability of a continuously active timer or system clock. Implementing such a timer would require access to a perennial source of energy, which for a structural health monitoring (SHM) application, could easily span several years.(More)
The shank regions of a polluted polymeric insulator are vulnerable to thermal damage from partial arcs. To alleviate this problem, it has recently been proposed to contour the polymeric surface with regular patterns of protuberances in order to reduce both the leakage current density and electric field strength in such regions, and by the same means to(More)
This paper describes the mechanical design, the software and hardware computer controls, and the measurement system used to construct the tracking wheel test facility as specified by the BS EN 62217:2006. The results of a long term test on polymeric insulators are also reported in the paper.
Electric field strength and leakage current density in the shank region of a polluted polymeric insulator may cause local dry-banding, with a risk of long-term degradation from partial-arc discharges. In a novel approach to dry-band control, the characteristics of silicone rubber surfaces with a textured finish are investigated and, depending on the(More)
Linear self-powering using a piezoelectric transducer is not well suited for detecting high-velocity mechanical impacts where the level of strain inside the structure could vary by orders of magnitude. In this paper we present a novel compressive self-powering technique that uses a non-linear impedance circuit to dynamically load the output of a(More)
The shank region of polluted polymeric insulators is susceptible to thermal damage where high current density and high electric field magnitude occurs. The recently proposed textured design consisting of hemispherical protuberances, aims to reduce the current density and the electric field gradient and increase the longitudinal creepage length without(More)