86,921 research outputs found
Accelerating the charge inversion algorithm with hierarchical matrices for gas insulated systems
No full textSurface charges accumulating on dielectrics during long-time operation of Gas Insulated High Voltage Direct Current (HVDC-GIS) equipments may affect the stable operation and could possibly trigger surface flashovers. In industrial applications, to quantify and identify the location of the surface charge accumulation from experimental measurements, the surface potential distribution is evaluated using, e.g., electrostatic probes, then the charge density is determined by solving an electrostatic problem based on an inversion procedure known as Charge Inversion Algorithm. The major practical limitation of such procedure is the inversion and the storage of the fully dense matrix arising from the representation via Integral Equations of the electrostatic phenomenon, resulting in O(N3) computational complexity and O(N2) memory requirement. In this paper it is shown how hierarchical matrices can be efficiently used to accelerate the charge inversion algorithm and, more importantly, reduce the..
A comparison between current-based integral equations approaches for eddy current problems
No full textIn this paper, a comparison between two current-based Integral Equations approaches for eddy current problems is presented. In particular, the very well-known and widely adopted loop-current formulation (or electric vector potential formulation) is compared to the less common J–φ formulation. Pros and cons of the two formulations with respect to the problem size are discussed, as well as the adoption of low-rank approximation techniques. Although rarely considered in the literature, it is shown that the J–φ formulation may offer some useful advantages when large problems are considered. Indeed, for large–scale problems, while the computational efforts required by the two formulations are comparable, the J–φ formulation does not require any particular attention when non-simply connected domains are considered
Application of FFT-PEEC method for nonlinear inductance extraction
No full textThis paper shows how the recently proposed Partial Element Equivalent Circuit (PEEC) method accelerated by the Fast Fourier Transform (FFT) (i.e., the FFT-PEEC method) can be efficiently adopted for the extraction of inductances when nonlinear ferromagnetic materials are involved. An efficient and simplified strategy for the inductance extraction by means of FFT-PEEC is proposed in order to speed-up the parameter extraction for many coil-current values. Such tool finds practical applications in the modelling of electromagnetic devices where the magnetic saturation of ferromagnetic media may be an undesirable phenomenon which, however, cannot be neglected, e.g., in power electronics or integrated inductors. Moreover, such tool can be particularly useful during the design of electronic devices which exploit saturation effects, such as voltage regulators, tunable core inductors, magnetic amplifiers, and fluxgate magnetometers
First meeting of the European canine lymphoma group: Workshop: State of the art and comparative aspects in canine lymphoma: CH-Lugano, 22 June 2013
No full textThis satellite meeting to the 12th International Conference on Malignant Lymphoma was conceived to bring together European researchers focused on canine lymphoma to explore several facets of this promising model of human disease. A series of invited lectures showed striking similarities between the two diseases namely in topics related to pathogenesis, diagnosis and classification and therapy. In particular, the potential value of the model was shown at the level of the NF-kappa B/p65 pathway, the Bcl-2 family of proteins, Ki67 and the S-phase fraction, as well as the MMPs, VEGF and PDGF. The utility of the growing body of well-characterized canine cell lines was stressed. The value of cytology and flow cytometry as tools for diagnosis, disease progression monitoring and prognosis were emphasized, whereas the failure so far of the standard immunohistochemical panel to differentiate between germinal centre and non-germinal centre diffuse large B-cell lymphomas subtypes in dogs was discussed. Further contributions included the report of encouraging results from a chemo-immunotherapy trial administered to dogs with diffuse large B-cell lymphoma, an overview on the use of radiation therapy for canine lymphoma and the role of surgery in splenic lymphoma. Altogether, the success of this meeting, attended by more than 160 participants, documents the rising interest for the spontaneous canine lymphoma model. Copyright (C) 2013 John Wiley & Sons, Ltd
Paraneoplastic alopecia associated with hepatocellular carcinoma in a cat
No full textA 15-year-old spayed female domestic shorthair cat presented with alopecia associated with hepatocellular carcinoma. Clinical signs, which had commenced 6 months previously, included loss of appetite, loss of weight, and depression. As reported by the owner, the cat developed alopecia a week before referral. The hair loss was localized to the ventral aspect of the thorax and abdomen, medial aspect of front and hind limbs, and ventral aspect of the tail, and was associated with histological features consistent with paraneoplastic alopecia. At necropsy, multiple hepatic nodules were observed, and subsequent histopathological investigation showed cords and sheets of hepatocyte-like neoplastic cells positive for the hepatocyte marker (Hep Par 1), thereby demonstrating the hepatocellular origin of the tumour, which was diagnosed as a hepatocellular carcinoma. This is the first report of feline paraneoplastic alopecia associated with hepatocellular carcinoma confirmed by the Hep Par 1 marker
Hemispheric differences in the recognition of partly occluded objects by newly hatched domestic chicks (Gallus gallus)
No full textUn paesaggio culturale dell'Alta Padovana:evoluzione dell'ecotipo "a prato stabile" nei territori del Medio Brenta.
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