TO ERADICATION OF VOLTAGE SAG AND HARMONICS IN DISTRIBUTION SYSTEM USING DVR WITH CAPACITOR COMPENSATION SCHEME

Power Quality (PQ) is that the most vital perspectives on transmission and distribution ranges. The availability of high-grade electric powered offerings wished for the customers illustrates this idea. The voltage sag and swell square degree the most not unusual PQ problems that in particular rise up in the distribution systems because of the truth that it's going to cause tool tripping, failure of stress systems, closure for home and business instrumentality. The Dynamic Voltage Restorer (DVR) associated nonparallel has amazing dynamic talents and is a flexible solution for PQ troubles. Ultra-capacitors (UCAP) have quality developments like excessive strength and espresso electricity density important for the mitigation of voltage sag and swell. This paper offers AN extended DVR topology capable of handing over deep, prolonged mitigation for power terrific troubles. Within the planned DVR, UCAP is employed as strength storage because it offers immoderate electricity in a totally short c software language length of it gradual. The DVR is protected into Ultra capacitor via a bifacial DC-DC converter which facilitates in supplying a rigid dc-link voltage and conjointly enables in compensating transient voltage sag and voltage swell. PI Controller is hired in DVR for electricity exceptional improvement. The simulation model for the proposed device has been superior in MATLAB and therefore the performance over famous DVR is legitimate with the effects obtained

Insights into Electrochemical Oxidation of NaO₂ in Na–O₂ Batteries via Rotating Ring Disk and Spectroscopic Measurements

O₂ reduction in aprotic Na–O₂ batteries results in the formation of NaO₂, which can be oxidized at small overpotentials (<200 mV) on charge. In this study, we investigated the NaO₂ oxidation mechanism using rotating ring disk electrode (RRDE) measurements of Na−O₂ reaction products and by tracking the morphological evolution of the NaO₂ discharge product at different states of charge using scanning electron microscopy (SEM). The results show that negligible soluble species are formed during NaO₂ oxidation, and that the oxidation occurs predominantly via charge transfer at the interface between NaO₂ and carbon electrode fibers rather than uniformly from all NaO₂ surfaces. X-ray absorption near edge structure (XANES), and X-ray photoelectron spectroscopy (XPS) measurements show that the band gap of NaO₂ is smaller than that of Li₂O₂ formed in Li–O₂ batteries, in which charging overpotentials are much higher (∼1000 mV). These results emphasize the importance of discharge product electronic structure for rationalizing metal–air battery mechanisms and performance

Towards a methodology for integrated history and philosophy of science

We respond to two kinds of skepticism about integrated history and philosophy of science: foundational and methodological. Foundational skeptics doubt that the history and the philosophy of science have much to gain from each other in principle. We therefore discuss some of the unique rewards of work at the intersection of the two disciplines. By contrast, methodological skeptics already believe that the two disciplines should be related to each other, but they doubt that this can be done successfully. Their worries are captured by the so-called dilemma of case studies: On one horn of the dilemma, we begin our integrative enterprise with philosophy and proceed from there to history, in which case we may well be selecting our historical cases so as to fit our preconceived philosophical theses. On the other horn, we begin with history and proceed to philosophical reflection, in which case we are prone to unwarranted generalization from particulars. Against worries about selection bias, we argue that we routinely need to make explicit the criteria for choosing particular historical cases to investigate particular philosophical theses. It then becomes possible to ask whether or not the selection criteria were biased. Against worries about unwarranted generalization, we stress the iterative nature of the process by which historical data and philosophical concepts are brought into alignment. The skeptics' doubts are fueled by an outdated model of outright confirmation vs. outright falsification of philosophical concepts. A more appropriate model is one of stepwise and piecemeal improvement