Determination of the Insulation Condition in Synchronous Generators: Industrial Methods and Case Study

[EN] Electrical Machines, and especially Synchronous Generators (SG), take a significant position in Power Generation plants and in Industry Production Lines and their unscheduled outages may have very negative repercussions. One of the main reasons for their failure relies on the degradation of their stator and rotor insulation systems. Although there are several industrial methods that are commonly used for diagnosing the health of such parts, some critical aspects remain unsolved. This paper reviews the different diagnostic methods and techniques that are most commonly used in practice to determine the condition of these two insulation systems in SG, emphasizing their respective drawbacks and analyzing their variants. Consequently, a case study on a SG operating in a Power Plant in Greece which illustrates the application of all these methods is presented.Part of this research was funded by Generalitat Valenciana, Conselleria de Educacion, Investigacion, Cultura y Deporte, under Grant AICO/2019/224. The authors of this article would like to thank Pericles Stratigopoulos, director of the Komotini Power Plant, Public Power Corporation S.A., Greece, for providing the pictures of the stator and rotor and the measurements for this SG.Verginadis, D.; Antonino-Daviu, J.; Karlis, A.; Danikas, M. (2022). Determination of the Insulation Condition in Synchronous Generators: Industrial Methods and Case Study. IEEE Industry Applications Magazine. 28(2):67-77. https://doi.org/10.1109/MIAS.2021.3114659677728

Agent-based interoperability for e-government

The provision of valuable e-government services depends upon the capacity to integrate the disperse provision of services by the public administration and thus upon the availability of interoperability platforms. These platforms are commonly built according to the principles of service oriented architectures, which raise the question of how to dynamically orchestrate services while preserving information security. Recently, it was presented an e-government interoperability model that preserves privacy during the dynamic orchestration of services. In this paper we present a prototype that implements that model using software agents. The model and the prototype are briefly described; an illustrative use case is presented; and the advantages of using software agents to implement the model are discussed. © Springer International Publishing Switzerland 2013

Brokerage for Quality Assurance and Optimisation of Cloud Services: An Analysis of Key Requirements

As the number of cloud service providers grows and the requirements of cloud service consumers become more complex, the latter will come to depend more and more on the intermediation services of cloud service brokers. Continuous quality assurance and optimisation of services is becoming a mission-critical objective that many consumers will find difficult to address without help from cloud service intermediaries. The Broker@Cloud project envisages a software framework that will make it easier for cloud service intermediaries to address this need, and this paper provides an analysis of key requirements for this framework. We discuss the methodology that we followed to capture these requirements, which involved defining a conceptual service lifecycle model, carrying out a series of Design Thinking workshops, and formalising requirements based on an agile requirements information model. Then, we present the key requirements identified through this process in the form of summarised results

Data Mining in Electrical Machine Maintenance Reports

Industrial electrical machine maintenance logs pertinent information, such as fault causality and earlier indications, in the form of a semi-standardized report, previously written and now in digital form. New practices in predictive maintenance, state-of-the-art condition monitoring, include increasing applications of machine learning. Reports contain a large volume of natural text in various languages and semantics, proving costly for feature extraction. This chapter aims to present novel techniques in information extraction to enable literature access to this untapped information reserve. A high level of correlation between text features and fault causality is noted, encouraging research for extended application in the scope of electrical machine maintenance, especially in artificial intelligence indication detection training. Furthermore, these innovative models can be used for decision-making during the repair. Information from well-trained classifiers can be extrapolated to advance fault causality understanding

PLAY: Semantics-based Event Marketplace

International audienceIn this paper we present PLAY Platform, a Web-oriented distributed semantic middleware that serves as an Event M arketplace: the place where heterogeneous events can be integrated and combined. The purpose of the platform is to derive useful information from diverse real-time sources such as collaborative processes. The platform provides technology where instant results are needed or where heterogeneous data must be integrated on the fly or where the data arrive fast enough to require the stream processing nature of our approach. The main advantages of the platforms are its scalability (cloud-based nature) and the expressivity of the event combinations that can be defined (using both real-time and historical data). The platform has been applied in a use case about Personal data management. In this paper we present some results from the validation, focusing on smartphone and social media integration

A facile approach to hydrophilic oxidized fullerenes and their derivatives as cytotoxic agents and supports for nanobiocatalytic systems

A facile, environment-friendly, versatile and reproducible approach to the successful oxidation of fullerenes (oxC60) and the formation of highly hydrophilic fullerene derivatives is introduced. This synthesis relies on the widely known Staudenmaier’s method for the oxidation of graphite, to produce both epoxy and hydroxy groups on the surface of fullerenes (C60) and thereby improve the solubility of the fullerene in polar solvents (e.g. water). The presence of epoxy groups allows for further functionalization via nucleophilic substitution reactions to generate new fullerene derivatives, which can potentially lead to a wealth of applications in the areas of medicine, biology, and composite materials. In order to justify the potential of oxidized C60 derivatives for bio-applications, we investigated their cytotoxicity in vitro as well as their utilization as support in biocatalysis applications, taking the immobilization of laccase for the decolorization of synthetic industrial dyes as a trial case.Peer ReviewedPostprint (published version

Synthesis, structural characterization and biological studies of novel mixed ligand Ag(I) complexes with tri-phenylphosphine and aspirin or salicylic acid

Two new mixed ligand silver(I) complexes of formulae {[Ag(tpp)3(asp)](dmf)} (1) (aspH = o-acetylsalicylic acid and tpp = triphenylphosphine) and [Ag(tpp)2(o-Hbza)] (2) (o-HbzaH = o-hydroxy-benzoic acid) were synthesized and characterized by elemental analyses, spectroscopic techniques and X-ray crystallography at ambient conditions. Three phosphorus and one carboxylic oxygen atoms from a de-protonated aspirin ligand in complex 1 and two phosphorus and two carboxylic oxygen atoms from a chelating o-Hbza anion in complex 2 form a tetrahedral geometry around Ag(I) ions in both complexes. Complexes 1 and 2 and the silver(I) nitrate, tpp, aspNa and o-HbzaH were tested for their in vitro cytotoxic activity against leiomyosarcoma cells (LMS), human breast adenocarcinoma cells (MCF-7) and normal human fetal lung fibroblasts (MRC-5) cells with Thiazolyl Blue Tetrazolium Bromide (MTT) assay. For both cell lines 1 and 2 were found to be more active than cisplatin. Additionally, 1 and 2 exhibit lower activity on cell growth proliferation of MRC-5 cells. The type of LMS cell death caused by 1 and 2 were evaluated in vitro by use of flow cytometry assay. The results show that at concentrations of 1.5 and 1.9 lV of complex 1, 44.1% and 69.4%, respectively of LMS cells undergo programmed cell death (apoptosis). When LMS cells were treated with 1.6 and 2.3 lM of 2, LMS cells death was by 29.6% and 81.3%, respectively apoptotic. Finally, the influence of the complexes 1 and 2, upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was kinetically and theoretically studied. The binding of 1 and 2 towards LOX was also investigated by Saturation Transfer Difference (STD) 1 H NMR experiment

Interactions of biologically active substances with electromagnetic fields: experimental study

The effects of electromagnetic fields (EMFs) have been proved by a large number of studies and specifically from epidemiological studies. A major “breakthrough” in EMFs research is to establish the mechanism by which EMFs cause alterations on biological systems. In this PhD thesis, the effects of the resonant electromagnetic spectrum of the SnMNA complex on in vitro, ex vivo and in vivo models and the possible synergistic phenomenon of the complex activity and its EMFs spectrum were studied. Furthermore, the effects of morphine’s resonant electromagnetic spectrum as analgesic in a series of in vivo experiments were studied. In vitro studies showed that SnMNA complex presented potent cytotoxic activity (200 times more potent than of cisplatin) on LMS and MCF-7 cells and let both cell lines to apoptosis. The percentage of apoptotic cells was increasing as the concentrations of SnMNA were increasing, while cells presented growth arrest at G2/M phase of cell cycle. In vivo studies showed that SnMNA complex caused total necrosis of tubules and glomeruli in kidneys and dilatation of sisunoids and vacuolation of liver hepatocytes at a single dose of 80mg/kg BW, while chronic administration (4 repeated times) of 5.4mg/kg BW presented mild toxicity. Moreover, SnMNA administration at 4x5.4mg/kg BW prolonged the Mean Survival Time (MST) at about 200% while 30% of these animals were cured. Data from aggregometer analysis revealed that SnMNA complex could also act as an antiplatelet agen, indicating its possible antimetastatic effects. Twenty seven resonant-electromagnetic frequencies (r-EMFs) were selected from the transformation of chemical shifts (in ppm) of NMR spectrum of SnMNA complex. Exposure of LMS and MCF-7 cells on these r-EMFs increased the cytotoxic activity, while the cytotoxic activity of the complex and its EMFs (synergy) was similar to that of SnMNA complex. Also, exposure of LMS cells to the r-EMFs caused apoptosis similar to that caused by complex, while cells presented growth arrest at G2/M phase of cell cycle. Exposure of tumor-bearing Wistar rats to r-EMFs prolonged the MST and 30% were cured, while no toxic effects were presented. Exposure of rats on 36 r-EMFs, derived from morphine’s NMR spectrum, increased by 50% the index of analgesic activity similar to that of morphine’s administration (10mg/kg BW). The latter indicates that the appropriate “information” of biologically active substance could be transferred by exposure of various targets to its resonant electromagnetic fields (energy fingerprint). This exposure can cause similar effects compared to those caused by the biological active substances. Concluding, the NMR spectrum and so the r-EMFS of active substances can be used to cause similar effects as those of the initial substances without any side effect.Η επίδραση των ηλεκτρομαγνητικών πεδίων στα βιολογικά συστήματα έχουν αποδειχθεί μέσω ενός μεγάλου αριθμού μελετών και πιο συγκεκριμένα από επιδημιολογικές μελέτες. Ένα σημαντικό βήμα στην έρευνα των ηλεκτρομαγνητικών πεδίων είναι να αποδειχθεί ο μηχανισμός με τον οποίο αυτά μπορούν να προκαλέσουν αλλαγές στα ζώντα συστήματα. Στην παρούσα διδακτορική διατριβή μελετήθηκε η επίδραση του φάσματος συντονισμού του SnMNA συμπλόκου σε in vitro, ex vivo και in vivo μοντέλα και η πιθανή εμφάνιση του φαινομένου της συνέργειας των δράσεων του συμπλόκου και του ηλεκτρομαγνητικού φάσματος συντονισμού αυτού. Επίσης, μελετήθηκε η επίδραση του φάσματος συντονισμού της μορφίνης σε in vivo μοντέλα στην αύξηση της αναλγητικής ικανότητας σε επίμυες Wistar. Τα in vitro πειράματα έδειξαν ότι το SnMNA παρουσιάζει ισχυρή κυτταροτοξική δράση (200 φορές ισχυρότερη από την πλατίνα) στα LMS και MCF-7 κύτταρα και οδηγεί τα κύτταρα σε αποπτωτικό θάνατο. Σε αυξανόμενες συγκεντρώσεις του SnMNA αυξάνεται το ποσοστό της απόπτωσης με το μεγαλύτερο ποσοστό των κυττάρων να βρίσκεται στη φάση G2/M. Τα in vivo πειράματα έδειξαν ότι προκαλεί νεφροτοξικότητα με ολική νέκρωση των σωληναρίων και των σπειραμάτων των νεφρών στην εφάπαξ δόση των 80mg/kg ΣΒ, ενώ στη χορήγηση 4x5.4mg/kg ΣΒ (χρόνια τοξικότητα) εμφανίστηκε ήπια τοξικότητα. Επίσης, αύξησε (4x5.4mg/kg ΣΒ) το μέσο χρόνο επιβίωσης των καρκινοπαθών πειραματόζωων της ομάδας πειράματος κατά 200%, ενώ το 30% αυτών επιβίωσε. Παράλληλα, το SnMNA λειτούργησε και ως αντιμεταστατικός παράγοντας βάσει των αποτελεσμάτων της αιμοπεταλιακής συσσώρευσης. Από το NMR φάσμα του SnMNA προέκυψαν 22 συχνότητες συντονισμού. Η έκθεση των LMS και MCF-7 κυττάρων σε αυτές τις συχνότητες οδήγησε σε αύξηση της κυτταροτοξικότητας, ενώ στην περίπτωση της συνέργειας η δράση αυτή ήταν ανάλογη της δράσης του συμπλόκου. Η έκθεση στις συχνότητες προκάλεσε απόπτωση αντίστοιχη του συμπλόκου, ενώ το μεγαλύτερο ποσοστό των εκτιθέμενων κυττάρων βρίσκεται στη φάση G2/M. Επίσης, δεν προκάλεσε τοξικότητα στους φυσιολογικούς επίμυες Wistar, ενώ επιμήκυνε το μέσο χρόνο επιβίωσης στους καρκινοπαθείς επίμυες και το 30% αυτών επιβίωσε. Η έκθεση των πειραματόζωων για 5 ώρες στο ηλεκτρομαγνητικό φάσμα 36 συχνοτήτων συντονισμού της μορφίνης οδήγησε σε αύξηση της αναλγησίας στο ήμισυ αυτής που προκαλεί η χορήγηση της μορφίνης σε δόση 10mg/kg ΣΒ. Είναι πιθανό ότι μέσω της εκπομπής των ΗΜΓΣΣ να μεταφέρεται η κατάλληλη «πληροφορία» του εκάστοτε μορίου (ενεργειακό αποτύπωμα) η οποία μπορεί να αναπαραγάγει παραπλήσια αποτελέσματα όπως το αρχικό μόριο. Η λήψη του NMR φάσματος οποιουδήποτε βιολογικά δραστικού μορίου και η χρησιμοποίηση των συχνοτήτων συντονισμού αυτού δίνει τη δυνατότητα προσομοίωσης της δράσης του τουλάχιστον σε πολύ μεγάλο βαθμό και χωρίς την εμφάνιση ανεπιθύμητων παρενεργειών