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Electric field distortion caused by space charge accumulation is one of the challenges in the development of insulating liquid immersed converter transformers and battery energy storage. This paper studies the impact of temperature and moisture content on field distortion in synthetic ester through an improved computational model incorporating the time-development permittivity of insulating liquid, and the test results indicated highly accurate simulation results of electric field distribution can be produced compared with the previous model. Charge mobility and charge density in synthetic ester were extracted from frequency dielectric spectroscopy test results, which were then used to calculate field distortion by the developed computational model. Simulation results indicated that the field distortion in synthetic ester decreases with temperature due to the enhanced permittivity caused by space charge accumulation, while it increases with moisture content due to the increased charge density from the dissociation of water. [ABSTRACT FROM AUTHOR]

The lumped element network model has been proven to be an efficient tool for the interpretation of transformer Frequency Response Analysis. However, it is challenging to obtain parameters of the model if transformer design information is unavailable. In such a case, optimisation algorithms can be used for gray‐box model parameter estimation. A methodology is developed by the authors to establish a transformer network model without winding design data, and instead, end‐to‐end open circuit Frequency Response and other terminal test results are utilised; and Genetic Algorithm is applied to approximate the unknown parameters of the model. The modelling approach developed is independent of the unit number of the network model and therefore guarantees the accuracy of optimisation. Furthermore, it can deal with transformers with a complicated winding structure such as interleaved disc type winding. Two single windings, helical and interleaved disc type, and a single‐phase 144/13 kV 60 MVA transformer are used to demonstrate the method. FRA spectra produced by the best estimated gray‐box model and the corresponding white‐box model are compared. The main features in amplitude and phase spectra are well matched, with low values of Relative Standard Deviation, for both single windings and transformer. Estimated electrical parameters show a high consistency with reference values, which are calculated based on winding design data. This validates the methodology and gives confidence to apply grey‐box modelling for FRA interpretation. [ABSTRACT FROM AUTHOR]

The Himalayan marmot (Marmota himalayana), a natural host and transmitter of plague, is also susceptible to the hepadnavirus infection. To reveal the genetic basis of the hepadnavirus susceptibility and the immune response to plague, we systematically characterized the features of immune genes in Himalayan marmot with those of human and mouse. We found that the entire major histocompatibility complex region and the hepatitis B virus pathway genes of the Himalayan marmot were conserved with those of humans. A Trim (tripartite motif) gene cluster involved in immune response and antiviral activity displays dynamic evolution, which is reflected by the duplication of Trim5 and the absence of Trim22 and Trim34. Three key regions of Ntcp, which is critical for hepatitis B virus entry, had high identity among seven species of Marmota. Moreover, we observed a severe alveolar hemorrhage, inflammatory infiltrate in the infected lungs and livers from Himalayan marmots after infection of EV76, a live attenuated Yersinia pestis strain. Lots of immune genes were remarkably up-regulated, which several hub genes H2r[gamma], Tra29, and Nlrp7 are placed at the center of the gene network. These findings suggest that Himalayan marmot is a potential animal model for study on the hepadnavirus and plague infection. Key words: Himalayan marmot, immune system, hepadnavirus, plague. La marmotte de l'Himalaya (Marmota himalayana), un hote naturel qui peut transmettre la peste, est egalement sensible a l'infection par l'hepadnavirus. Afin de reveler l'assise genetique de la sensibilite a l'hepadnavirus et de la reponse immunitaire a la peste, les auteurs ont systematiquement caracterise les genes du systeme immunitaire chez la marmotte de l'Himalaya avec ceux chez l'humain et la souris. Les auteurs ont trouve que la region entiere du complexe majeur d'histocompatibilite et les genes du sentier du virus de l'hepatite B chez la marmotte de l'Himalaya sont conserves avec ceux presents chez l'humain. Un groupe de genes Trim (<< a motif tripartite >>) implique dans la reponse immunitaire et l'activite antivirale presentait une evolution dynamique, laquelle se reflete par la duplication de Trim5 et l'absence des genes Trim22 et Trim34. Trois regions cles de Ntcp, lequel est critique pour l'entree du virus de l'hepatite B, presentaient un fort niveau d'identite au sein de sept especes de Marmota. De plus, les auteurs ont observe une severe hemorragie alveolaire, un infiltrat inflammatoire dans les poumons et le foie chez des marmottes de l'Himalaya apres infection avec l'EV76, une souche vivante attenuee du Yersinia pestis. Plusieurs genes du systeme immunitaire etaient remarquablement plus fortement exprimes, dont plusieurs genes (H2r[gamma], Tra29 et Nlrp7) qui sont au coeur de reseaux de genes. Ces observations suggerent que la marmotte de l'Himalaya constitue une espece modele potentielle pour l'etude de l'infection avec l'hepadnavirus et la peste. [Traduit par la Redaction] Mots-cles : marmotte de l'Himalaya, systeme immunitaire, hepadnavirus, peste., Introduction The Himalayan marmot (Marmota himalayana) is a marmot species that inhabits alpine grasslands throughout the Himalayan regions and on the Tibetan Plateau (Nikol'skii and Ulka 2006; Hoffmann et al. [...]

At present, the development of electric vehicles (EV) is limited by the lack of charging facilities. While the construction of charging stations is slowing down because of the small ownership of EV and the high operational cost. The mobile charging vehicles (MCV) are proposed to replace the charging station. At first, this paper introduces the MCV’s operation architecture. Then the spatial charging demand is estimated based on the travel chain. At last, the allocation method of mobile charging vehicles is studied in detail with the result of estimation result. The simulation result shows that proper number of MCV can replace the function of charging station as well as meet the needs of charging services. DOI: http://dx.doi.org/10.5755/j01.eie.24.1.20153

A three-dimensional model based on molecular dynamics has been developed to describe the formation of a single cathode spot in vacuum arcs. The formation of the cathode spot is assumed to be controlled by the plasma ions, the effect of which is simulated in LAMMPS through the process of ion bombardment. The cathode is represented by structured copper atoms, while the ions are continuously injected into the domain with a certain velocity towards the cathode surface. Ion bombardment leads to the appearance of a crater, which is caused by the accumulation of pressure effect against the relaxation of substrate temperature. The size of the crater is found to be determined by the spatial distribution of the injected ions. The formation of the cathode spot is also scrutinised by electron emission from the cathode surface with variable surface temperature during the cathode spot development process. In addition, the evaporated atoms forming the metal vapour are observed. This study provides a description of the formation of the cathode spot at microscale, which shall be helpful to further studies of the arc rooting and arc contact (electrode) erosion in vacuum environment. [ABSTRACT FROM AUTHOR]