Three-phase voltage outages kompensator with cascaded multilevel converter

The paper presents a laboratory prototype of the three-phase transformer less voltage outages compensator with an energy storage based on high voltage supercapacitors. The system described is able to protect an isolated grid e.g. in industry against short voltage interruptions, dips and sags. An idea of a control method as well as a Digital controller has been presented, too

Pontastacus leptodactylus (Eschscholtz, 1823) and Faxonius limosus (Rafinesque, 1817) as New, Alternative Sources of Chitin and Chitosan

The growing demand for chitin and chitosan makes it necessary to look for new sources of these polymers and to develop more environmentally friendly methods for their isolation. The subjects of the current study were chitin and chitosan extracted from shells of two crayfish species: P. leptodactylus and F. limosus. The obtained polymers were characterized by physicochemical proper- ties (molecular weight, thermal stability, and structure). The obtained chitosan was evaluated regard- ing biocompatibility and antimicrobial activity. The yield of chitin obtained from P. leptodactylus and F. limosus with a standard method was 22 ± 2.7% and 20 ± 3.6% (w/w), respectively (a preliminary extraction with a natural deep eutectic solvent was performed successfully only for P. leptodactylus). The yield of chitosan production was 15 ± 0.3% and 14 ± 4.2%, respectively. Both chitosan samples showed antimicrobial activity against E. coli and S. aureus. Cytotoxicity assays revealed a time- and concentration-dependent effect, with a milder impact at concentrations up to 250 μg/mL. A more favourable profile was observed for chitosan from F. limosus shells

Application of Time Series Analyses in Big Data: Practical, Research, and Education Implications

ABSTRACT The application of Big Data and time series models is currently at an early stage. This paper examines the relevance and use of time series analyses for Big Data and business analytics by discussing the emergence of Big Data in business, presenting time series models, and providing an example of how time series models can be efficiently and effectively applied in accounting and auditing using Big Data. Using sophisticated Big Data and time series models, millions of transactions can be searched to spot patterns and detect abnormalities and irregularities. The time series model and Big Data analysis presented in this paper provide policy, practical, educational, and research implications. Businesses and management can use our suggested time series model and Big Data analysis in their predictive models of managerial strategies, decisions, and actions. Business schools and accounting programs can integrate the time series model, Big Data, and data analytics into business and accounting education.</jats:p