Voltage gradient limitation of IGBTS by optimised gate-current profiles

Author(s):  
G. Schmitt ◽  
R. Kennel ◽  
J. Holtz
Author(s):  
Fabio Galeotti ◽  
Federica Capitani ◽  
Francesca Maccari ◽  
Veronica Mantovani ◽  
Nicola Volpi

Abstract Propolis is important in complementary and alternative medicine having well-known therapeutic applications. Artepillin C, a main component of Brazilian (green) propolis, has attracted great attention for its anticancer action. Consequently, the synthesis of artepillin C has been reported but, due to the limited yield and elevated costs, this biomolecule is largely produced from Brazilian propolis. We report the capillary electrophoresis (CE) separation of artepillin C in Brazilian propolis also comparing the results with those of HPLC-UV-MS. Optimal separation was obtained with a simple buffer constituted of sodium tetraborate 30 mM pH 9.2 and detection at 210 nm. Artepillin C and the polyphenols of propolis were fully separated with a voltage gradient of 30 to 8 kV and a current of 300 μA for a total run of 50 min. The sensitivity of CE-UV was 22 times greater than HPLC-UV and 100 times more than HPLC-MS with also a stronger reduction in the run time and a greater robustness and reproducibility. The development of CE as an effective and reliable method for the analysis of artepillin C is desired as the standardized quality controls are essential before propolis or its biomolecules can be adopted routinely in nutraceuticals, food ingredients and therapeutic applications.


IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Mehedi Hassan ◽  
M. J. Hossain ◽  
Rakibuzzaman Shah

2012 ◽  
Vol 253-255 ◽  
pp. 1098-1101
Author(s):  
Hong Tao Hu

The natural and electrokinetic enhanced migration method was studied by the experiments in groundwater contaminated by heavy metal Pb in this work. The experimental results showed that the variation rule of Pb reflected that its migration was weak and the removal efficiency was only 9.30% near the anode in the natural seepage condition, but under the enhanced migration and remediation function, the pollutants could be enriched and removed faster, thus the removal efficiency of Pb was 46.72% near the anode at the end of experiment when the experimental voltage gradient was 0.28V/cm, which made known that this electrokinetic enhanced migration of Pb in contaminated groundwater was more effective method than that of natural seepage migration and enhanced the removal of contaminant in aquifer.


2021 ◽  
pp. 108201322199161
Author(s):  
Merve Tuçe Tunç ◽  
Arda Akdoğan ◽  
Cemalettin Baltacı ◽  
Zeliha Kaya ◽  
Halil İbrahim Odabaş

Pekmez is a concentrated syrup-like food conventionally produced by vacuum evaporation process from sugar-rich fruits. In this study, the applicability of grape pekmez production by ohmic heating assisted vacuum evaporation (ΩVE) method was investigated. Conventional vacuum evaporation (CVE) and ΩVE methods were compared in terms of physicochemical properties, HMF (5-hydroxymethylfurfural) contents, rheological properties, and energy consumptions. ΩVE was run at four different voltage gradients (17.5, 20, 22.5, and 25 V/cm). Total process times for grape pekmez production were determined as 57, 28.5, 32, 39, and 50 minutes for CVE, ΩVE (25 V/cm), ΩVE (22.5 V/cm), ΩVE (20 V/cm) and ΩVE (17.5 V/cm), respectively. Energy consumption of CVE method was higher than ΩVE method for all voltage gradients. Energy efficiency increased as the voltage gradient increased. There was no significant difference between CVE and ΩVE methods for HMF contents. The results show that the ΩVE method could be an alternative to the CVE process for grape pekmez production.


Author(s):  
Farah Asyikin Abd Rahman ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Ungku Anisa Ungku Amirulddin ◽  
Miszaina Osman

AbstractThis paper presents a study on the performance of a fourth rail direct current (DC) urban transit affected by an indirect lightning strike. The indirect lightning strike was replicated and represented by a lightning-induced overvoltage by means of the Rusck model, with the sum of two Heidler functions as its lightning channel base current input, on a perfect conducting ground. This study aims to determine whether an indirect lightning strike has any influence with regard to the performance of the LRT Kelana Jaya line, a fourth rail DC urban transit station arrester. The simulations were carried out using the Electromagnetic Transients Program–Restructured Version (EMTP–RV), which includes the comparison performance results between the 3EB4-010 arrester and PDTA09 arrester when induced by a 90 kA (9/200 µs). The results demonstrated that the PDTA09 arrester showed better coordination with the insulated rail bracket of the fourth rail. It allowed a lower residual voltage and a more dynamic response, eventually resulting in better voltage gradient in the pre-breakdown region and decreased residual voltage ratio in the high current region.


2005 ◽  
Vol 49 (3) ◽  
pp. 505-511 ◽  
Author(s):  
Zhi Cui ◽  
Juin J. Liou ◽  
Yun Yue ◽  
Hei Wong

Sign in / Sign up

Export Citation Format

Share Document