In this paper, analytical closed-form expressions to accurately estimate the pull-in characteristics of an electrostatically-actuated doubly-clamped nanobeam are derived and examined. In this regard, a coupled electro-mechanical problem for the nano-actuator is first presented assuming a single mode approximation while taking into account all the possible structural, electrical and nanoscale ef...

Load shedding has been extensively studied because of multiple power system failure occurrences worldwide. Reliable techniques are required to provide rapid and precise load shedding to avert voltage collapse in power networks. Meta-heuristic optimization approaches are currently the widely developed methods because of their robustness and flexibility in dealing with complex and non-linear syst...

This paper compares two different Optimal Power Flow (OPF) formulations that consider voltage security in power systems. The techniques are both based on multi-objective optimization methodologies, so that operating costs and losses can be minimized while maximizing the “distance” to voltage collapse. The techniques are described in detail and compared to study their similarities, as well as a...

Current collapse effects in an Al0.25Ga0.75N/GaN HFET have been investigated under pulsed bias conditions, and a detailed investigation of current responses to changes in drain or gate bias voltage (drain-lag and gate-lag, respectively) has been performed. Three components of transient current response to changes in drain and gate bias voltages are distinguished. Surface treatment using KOH etc...

We investigate the impact of structural disorder on electronic transport in gold nanocrystal monolayers. Arrays ranging from void-filled networks to well-ordered superlattices show clear voltage thresholds VT due to Coulomb blockade, and temperature-independent conduction indicative of quantum tunneling. Current-voltage characteristics of arrays with and without long-range structural order were...

The purpose of this paper is to study the reactive power sensitivity as an index for finding out the weakest bus. Voltage Collapse point is also determined from the P-V and Q-V curves of the weakest and next weakest bus. The way of finding out Voltage Stability Margin is also proposed. Finally, a method to compensate the reactive power of the weakest bus to improve its stability is also propose...

Power system security is one of the major concerns in competitive electricity markets driven by trade demands and regulations. If the system is found to be insecure, timely corrective measures need to be taken to prevent system collapse. This paper presents an approach based on a counterpropagation neural network (CPNN) to identify and rank the contingencies expected to reduce or eliminate the ...

This paper focuses on experimental results to prove that motor current signature analysis (MCSA) can diagnose shorted turns in low voltage stator windings of 3-phase induction motors using LabVIEW. The diagnostic strategy is presented and variables that influence the diagnosis are discussed. Current spectra from motors with short-circuited turns (with and without short circuit current limiting ...

By solving the problem of very long test time on reliability qualification for Light-emitting Diode (LED) products, the accelerated degradation test with a thermal overstress at a proper range is regarded as a promising and effective approach. For a comprehensive survey of the application of step-stress accelerated degradation test (SSADT) in LEDs, the thermal, photometric, and colorimetric pro...

Outage of a heavily loaded transmission line or tripping of large generating unit may lead the system toward collapse. Under such circumstances, compared to other measures, load shedding procedure is an efficient method to make the power system voltage stable when many system variables are out of their normal ranges and the system is driven toward collapse. This paper introduces the concept of ...