1,574 research outputs found
A Comparative Study of Physicochemical, Dielectric and Thermal Properties of Pressboard Insulation Impregnated with Natural Ester and Mineral Oil
No full textNatural ester is considered to be a substitute of mineral oil in the future. To apply natural ester in large transformers safely, natural ester impregnated solid insulation should be proved to have comparable dielectric strength and thermal stability to mineral oil impregnated solid insulation. This paper mainly focuses on a comparative study of physicochemical, ac breakdown strength and thermal stability behavior of BIOTEMP natural ester/pressboard insulation and Karamay 25# naphthenic mineral oil/pressboard insulation after long term thermal ageing. The physicochemical and dielectric parameters including moisture, acids and the ac breakdown strength of these two oil/pressboard insulation systems at different ageing status were compared. The permittivity and ac breakdown strength of these two oil/pressboard insulation systems at different temperatures were also investigated. And a comparative result of the thermal stability behavior of these two oil/pressboard insulation systems with different ageing status was provided at last. Results show that though natural ester has higher absolute humidity and acidity during the long ageing period, the lower relative humidity of natural ester helps to keep its ac breakdown strength higher than mineral oil. The pressboard aged in natural ester also has higher ac breakdown strength than that aged in mineral oil. The lower relative permittivity ratio of natural ester impregnated paper to natural ester is beneficial to its dielectric strength. Using natural ester in transformer, the resistance to thermal decomposition of the oil/pressboard insulation system could be also effectively improved
<i>No se sabe</i>: entrevista a Nilda Ester Radman
No full textEntrevista a la médica veterinaria y bacterióloga clínica industrial Nilda Ester Radman, profesora titular de Parasitología Comparada en la Facultad de Ciencias Veterinarias de nuestra universidad y estudiosa de las enfermedades zoonóticas.Al hacer clic en el enlace que figura en "Documentos relacionados", pueden accederse a todos los trabajos de Nilda Ester Radman presentes en el repositorio.Radio Universidad Nacional de La Plat
Quantitative Analysis Ageing Status of Natural Ester-paper Insulation and Mineral Oil-paper Insulation by Polarization/Depolarization Current
No full textPolarization and Depolarization Current (PDC) technique is an effective tool to assess the condition of oil-paper insulation system in power transformers. So far the PDC behaviors of mineral oil-paper insulation have been widely investigated. However, with the increasing number of transformer choosing natural ester as its insulation oil, it is important to investigate the PDC characteristics of natural ester-paper insulation to see whether the PDC technique can also be used to assess the condition of new insulation system using natural ester in transformers accurately. In this research, natural esterpaper insulation sample and mineral oil-paper insulation sample were subjected to thermally accelerated ageing experiment at 110 °C for 120 days. The PDC characteristics of natural ester-paper insulation sample and mineral oil-paper insulation sample were compared over the ageing process. A new method for assessing the ageing condition of the oil-paper insulation in terms of the depolarization charge quantity was proposed. Results show that the polarization/depolarization current of natural ester-paper insulation sample is higher than that of mineral oil-paper insulation sample with the same ageing intervals. The depolarization charge quantity of both kinds of oil-paper insulation sample is very sensitive to their ageing conditions. There is an exponential relation between the stable depolarization charge quantity of both kinds of oil-paper insulation sample and the degree of polymerization (DP) of paper. The depolarization charge quantity can be used to predict the ageing condition of oil-paper insulation providing the measurement temperature is kept the same
Registrazioni di carri e ruote negli archivi di Knossos: analisi filologica e considerazioni storiche
No full textA note on the Linear A & B ideogram AB 131/VIN(um) 'wine' and its variants: references to time notation?
No full textThis paper sets out to explore the possibility of detecting references to time notation expressed in a semasiographic fashion in the Linear A and Linear B ideogram for wine: AB 131/VIN(um). This sign occurs in three variants, namely AB 131a, AB 131b and A 131c, with the latter variant being attested only in Linear A. Evidence will be put forward to argue that graphic alteration of the form of the main sign (AB 131a) was used as a method to give rise to variants of the sign (AB 131b, A 131c) meant to convey chronological information in a semasiographic way, i.e. without recourse to phonetic writing
Ester Formation
No full textThe present invention is in the field of a process for producing an ester, such as a biobased ester, from an aqueous biomass comprising solution, batch wise or continuously, wherein use of raw material is limited and if possible re-used. The present invention is in the field of green technology.BT/BiotechnologyApplied Science
Unsex me here. Ambivalenza e metamorfosi di Lady Macbeth
No full textMacbeth is the tragedy of desire. Lady Macbeth’s identity is a fiction of closure, namely a metonymic part that cannot represent the whole, the predetermined complexity with which being coincides with its subjectuality, made even more evident by the non-allocation of a name from the author. Being of Lady Macbeth is an aporia that says the true, because it built on an identification of opposites and destined inevitably to death to get a resolution of the internal conflict that embodies
Signs of the times? Testing the chronological significance of Linear A and B palaeography
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