2,735 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
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
Actualización del tratamiento del Melanoma Coroideo: revisión bibliográfica
No full textMuñoz Castillo, Miguel; director de proyecto: Mata Díaz, Ester2020-2021Grado en MedicinaFacultad de Medicin
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
Apertura del fallimento e rapporti di lavoro
No full textA partire dall’apertura della procedura liquidatoria, i lavoratori sono sospesi senza retribuzione
e senza diritto di percepire misure di sostegno al reddito, a meno che non vi siano
rapide prospettive di cessione dell’azienda o di suoi rami. Per un certo periodo di tempo, inoltre,
ai prestatori è precluso dimettersi per giusta causa. Dopo essersi soffermati sulla natura e
sul fondamento giuridico della sospensione dei rapporti, regolata nell’art. 72 l.f. e, a partire dal
1° settembre 2021, nell’art. 189, d.lgs. n. 14/2019, ci si interroga sulla legittimità costituzionale
di tali norme che paiono arrecare un vulnus all’art. 4 Cost. e 38 Cost. per la combinazione fra
sospensione non retribuita del rapporto di lavoro e divieto di dimissioni “in tronco”.Starting from the opening of the liquidation procedure, employees are suspended without pay and without the right to receive income support measures, unless there are rapid prospects for the sale of the company. Furthermore, for a certain period of time, employees are not allowed to resign for just cause. After linging on the nature and the legal basis of the suspension of the contractual relation, the Author investigates the constitutional legitimacy of these rules which seem to cause a violation of art. 4 and art. 38 of the Constitution for the combination of unpaid suspension of the employment relationship and prohibition of immediate resignation
Black European Inscriptions and the Challenge to Modern Essentialist Identities: The Case of Bernardine Evaristo’s Soul Tourists
No full textThis essay shows how the London-born Anglo-Nigerian author Bernardine Evaristo contributes, with her Soul Tourists (2005), to deconstructing modern European nationalist and racially exclusivist models by means of anti-essentialist representational strategies. Centred around the voyage by car and across Europe which, in the late eighties, leads two black Britons, Stanley Williams and Jessie O’Donnell, from England to the Middle East, the novel becomes an imaginative vehicle through which Evaristo represents the black presence as intrinsic to Europe since the th century and foregrounds the substantial contribution of black and mixed-race men and women to the cultural development of Western civilisation
Nella biblioteca di Hartmann Schedel: l'index librorum aldino del 1498 e le Decades rerum Venetarum di Marcantonio Sabellico
No full textThe contribution examines the first catalogue issued by Aldo Manuzio on 1 October 1498 and in particular the copy in the Österreichische Nationalbibliothek in Vienna (Ink. 7.A.13). A careful examination of the manuscript annotations, known to be by Hartmann Schedel, has enabled the author to identify the volume in which Schedel had the catalogue bound in his lifetime: a copy of Marcantonio Sabellico’s Decades rerum Venetarum (Venice, Andrea Torresani, 1487) also in the Österreichische Nationalbibliothek (Ink. 7.A.7). A detailed description of the item and Schedel's textual and graphic additions reveals for the first time what was one of the most significant books in the humanist's library and allow us to reconstruct the overall context of its use in the years immediately following its publication
Effect of zirconium-based conversion treatments of zinc, aluminium and magnesium on the chemisorption of ester-functionalized molecules
No full textThe effect of zirconium-based conversion of thermally vaporized zinc, aluminium and magnesium on the chemisorption of dimethylsuccinate was studied using attenuated total reflection – Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. Two competing chemisorption mechanisms contribute to interfacial bond formation. Hydrogen interactions on one hand were shown to occur between metal hydroxides and non-hydrolysed ester-groups of the molecule. On the other hand, both native and zirconium-treated substrates were shown to form interfacial carboxylate bonds with dimethylsuccinate, evidencing their capability of hydrolysing ester groups towards more reactive acid groups. Both interactions were shown to correlate to the metal oxide acid-base properties.(OLD) MSE-
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