Papers by Gustavo Dominguez
IEEE Transactions on Power Delivery, 2013
ABSTRACT
The optical emission of high current electric arcs confined between polymeric (PA6 - C6H11ON- and... more The optical emission of high current electric arcs confined between polymeric (PA6 - C6H11ON- and PMMA -C5H8O2-) and ceramic (Al2O 3) walls has been investigated experimentally in air. Arcs standing between copper electrodes with a separation of 8 mm under AC currents with peak values of 2 kA are studied here. The arc optical emission in the range between 250 and 700 nm is measured with a fast spectrometer at the mid-section of the arc column, while the spatial variations of the radiation is recorded with high speed photography. It is found that the ablation of the polymeric walls strongly reduce the intensity of emitted copper peaks as well as the arc column radius. Furthermore, a strong hydrogen Balmer-alpha peak is detected, which indicates the strong injection of hydrogen in the arc atmosphere by the ablation of the polymeric walls.
L'invention concerne une utilisation d'une composition polymere presentant de meilleures ... more L'invention concerne une utilisation d'une composition polymere presentant de meilleures proprietes electriques CC dans une couche de câble d'alimentation et un câble enveloppe d'au moins une couche comprenant ladite composition polymere.
La presente invention porte sur un materiel d'isolation pour des applications electriques hau... more La presente invention porte sur un materiel d'isolation pour des applications electriques haute tension comprenant un melange presentant entre 0 et 95 % en poids d'un premier constituant comprenant un polymere d'olefine Ci-8, et entre 5 et 100 % d'un second constituant comprenant un ionomere, l'ionomere etant un copolymere d'un polymere d'olefine C 1-8 et un acide acrylique partiellement neutralise et/ou un comonomere d'acide methacrylique ou une forme anhydride de celui-ci, comprenant entre 1 et 20 % en poids d'un comonomere, un sel de metal multivalent et un degre de neutralisation entre 1 et 100 %. La quantite totale de polymere d'olefine C 1-8 du premier et du second constituant est entre 80 et 99,5 % du poids total du materiau d'isolation. Le materiau d'isolation a une epaisseur d'au moins 3 mm. L'invention concerne egalement un procede de preparation et un materiau d'isolation, des applications electriques haute tensi...
26th International Conference on Electrical Contacts (ICEC 2012)
ABSTRACT
AIP Conference Proceedings, 2008
With the aim to investigate the influence of slight differences in the chemical structure of a fa... more With the aim to investigate the influence of slight differences in the chemical structure of a family of polymers on the response of these to electric perturbation fields, the relaxation behavior of three dimethoxy phenyl isomers of poly(benzyl methacrylate) have been studied.
2013 IEEE International Conference on Solid Dielectrics (ICSD), 2013
In high voltage DC applications one of the most critical parameters of insulation materials is th... more In high voltage DC applications one of the most critical parameters of insulation materials is the conductivity. It is however challenging to measure conductivity accurately, since it is influenced by composition, morphology, sample thickness, temperature, electric field strength and electrode material. There is no standard electrode material used for electrical characterization of insulation in research. It is known that different electrode materials give rise to different conduction currents and different space charge inside a polymer sample. It is also believed that oxide layers on metal electrodes influence the activation energy of the interface between the polymer sample and the metal electrode. In the present work, a pure non-stabilized LDPE was used to investigate different electrode materials. The following materials were investigated: brass, copper, aluminum, gold, silver and semi conductive polymer. The method of application of the electrodes onto the polymer samples was also varied. The results indicate that the contact material and the method how to connect the material to the polymer sample had an influence on the time behavior of the DC conductivity during 24h of polarization. It could be shown that the applied electrical field influenced the crystal structure of the sample.
Polymer, 2005
... a, Departamento de Termodinámica Aplicada, ETSII, Universidad Politécnica de Valencia, Camino... more ... a, Departamento de Termodinámica Aplicada, ETSII, Universidad Politécnica de Valencia, Camino de Vera s/n, 46071 Valencia, Spain. b, Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile. ...
2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2011
A new test cell is designed for making breakdown test on solid insulation materials for DC cables... more A new test cell is designed for making breakdown test on solid insulation materials for DC cables. Different from a conventional method, the new system uses a specially designed test chamber instead of insulation oil as ambient medium in order to prevent experiment failure from external flashover. The measure eliminates the need of the liquid and has ability to create
Polymer, 2005
By means of thermal sampling techniques, the fine structure of the g-relaxation zone of poly(meth... more By means of thermal sampling techniques, the fine structure of the g-relaxation zone of poly(methyl cyclohexyl methacrylate)s (P2MCHMA), (P3MCHMA), (P4MCHMA) were analyzed. Results reveal that in this relaxation zone, at least two peaks are present. These peaks are attributed to the cis and trans isomers. Loss permittivity of the polymers under study in this relaxation zone has been reproduced from the partial depolarization data by using the elementary relaxation times and activation energies. Results are in relatively good agreement with the experimental data previously obtained. Molecular mechanic calculations have been carried out in order to elucidate the characteristics and molecular origin of the relaxations observed in this zone. An interpretation of the height of the peaks associated to the cis-and trans-isomer in terms of strain energy (SE) have been carried out.
Macromolecules, 2006
The relaxation behavior of poly(3-methylbenzyl methacrylate), poly(3-fluorobenzyl methacrylate), ... more The relaxation behavior of poly(3-methylbenzyl methacrylate), poly(3-fluorobenzyl methacrylate), and poly(3-chlorobenzyl methacrylate) was thoroughly studied by broadband dielectric spectroscopy with the aim of investigating the influence of slight differences in ...
Macromolecules, 2010
ABSTRACT This work reports a comparative study of the response of poly(2,3-dimethoxybenzyl methac... more ABSTRACT This work reports a comparative study of the response of poly(2,3-dimethoxybenzyl methacrylate), poly(2,5-dimethoxybenzyl methacrylate), and poly(3,4-dimethoxybenzyl methacrylate) to electrical perturbation fields over wide frequency and temperature windows with the aim of investigating the influence of the location of the dimethoxy substituents in the phenyl moieties on the relaxation behavior of the polymers. The dielectric loss isotherms above Tg exhibit a blurred relaxation resulting from the overlapping of secondary relaxations with the glass−rubber or α relaxation. At high temperatures and low frequencies, the α relaxation is hidden by the ionic conductive contribution to the dielectric loss. As usual, the real component of the complex dielectric permittivity in the frequency domain increases with decreasing frequency until a plateau is reached corresponding to the glass−rubber (α) relaxation. However, at high temperatures, the real permittivity starts to increase again with decreasing frequency until a second plateau is reached, a process that presumably reflects a distributed Maxwell−Wagner−Sillars relaxation or α′ absorption. The α and α′ processes appear respectively as asymmetric and symmetric relaxations in the loss electrical modulus isotherms in the frequency domain. To facilitate the deconvolution of the overlapping absorptions, the time retardation spectra of the polymers were computed from the complex dielectric permittivity in the frequency domain using linear programming regularization parameter techniques. The spectra exhibit three secondary absorptions named, in increasing order of time γ′, γ, and β followed by the α relaxation. At long times and well separated from the α absorption the α′ relaxation appears. The replacement of the hydrogen of the phenyl group in position 2 by the oxymethyl moiety enhances the dielectric activity of the poly(dimethoxybenzyl methacrylate)s. The temperature dependence of the relaxation times associated with the different relaxations is studied, and the molecular origin of the secondary relaxations is qualitatively discussed.
Journal of Polymer Science Part B: Polymer Physics, 2006
Journal of Non-Crystalline Solids, 2007
Thermally stimulated depolarization current experiments (TSDC) have been carried out on poly(dicy... more Thermally stimulated depolarization current experiments (TSDC) have been carried out on poly(dicyclohexyl itaconate) (PDCHI) in the glassy state. The polymer exhibits three relaxation zones in the interval of temperature studied: a d-relaxation at $130 K, a complex cprocess, in the temperature interval of 140 K to 200 K, and the b-process in the range of 210-270 K. The loss factor of PDCHI in the glassy zone has been reproduced from the partial depolarization data by using the elementary relaxation times and activation energies. The results show the existence of at least two relaxation processes in c-and b-zones. A tentative explanation of the molecular origin of the observed secondary relaxations has been done by means of molecular mechanics (MM). At this respect, we perform a comparison of the relaxational data of PDCHI and those corresponding to PCHMA. This comparison allows us to confirm the relevant role played by the cyclohexyl ring in the d-and c-relaxations.
The Journal of Chemical Physics, 2005
The relaxation behavior of poly͑2,3-dichlorobenzyl methacrylate͒ is studied by broadband dielectr... more The relaxation behavior of poly͑2,3-dichlorobenzyl methacrylate͒ is studied by broadband dielectric spectroscopy in the frequency range of 10 −1-10 9 Hz and temperature interval of 303-423 K. The isotherms representing the dielectric loss of the glassy polymer in the frequency domain present a single absorption, called  process. At temperatures close to T g , the dynamical ␣ relaxation already overlaps with the  process, the degree of overlapping increasing with temperature. The deconvolution of the ␣ and  relaxations is facilitated using the retardation spectra calculated from the isotherms utilizing linear programming regularization parameter techniques. The temperature dependence of the  relaxation presents a crossover associated with a change in activation energy of the local processes. The distance between the ␣ and  peaks, expressed as log͑f max; / f max;␣ ͒ where f max is the frequency at the peak maximum, follows Arrhenius behavior in the temperature range of 310-384 K. Above 384 K, the distance between the peaks remains nearly constant and, as a result, the ␣ onset temperature exhibited for many polymers is not reached in this system. The fraction of relaxation carried out through the ␣ process, without  assistance, is larger than 60% in the temperature range of 310-384 K where the so-called Williams ansatz holds.
The Journal of Chemical Physics, 2008
This work describes the calculation of retardation time spectra by minimization of the square of ... more This work describes the calculation of retardation time spectra by minimization of the square of the differences between experimental compliance results and those recalculated from the spectra. Spectra were computed taking analytical complex dielectric results as the basis of the minimization process. Comparison of the spectra computed from both the complex dielectric permittivity and the dielectric loss with those calculated analytically shows that minimization methods based on complex dielectric permittivity data are more accurate than those based only on loss dielectric results.
Polymer, 2005
By means of thermal sampling techniques, the fine structure of the g-relaxation zone of poly(meth... more By means of thermal sampling techniques, the fine structure of the g-relaxation zone of poly(methyl cyclohexyl methacrylate)s (P2MCHMA), (P3MCHMA), (P4MCHMA) were analyzed. Results reveal that in this relaxation zone, at least two peaks are present. These peaks are attributed to the cis and trans isomers. Loss permittivity of the polymers under study in this relaxation zone has been reproduced from the partial depolarization data by using the elementary relaxation times and activation energies. Results are in relatively good agreement with the experimental data previously obtained. Molecular mechanic calculations have been carried out in order to elucidate the characteristics and molecular origin of the relaxations observed in this zone. An interpretation of the height of the peaks associated to the cis-and trans-isomer in terms of strain energy (SE) have been carried out.
The Journal of chemical …, 2005
The relaxation behavior of poly(2,3-dichlorobenzyl methacrylate) is studied by broadband dielectr... more The relaxation behavior of poly(2,3-dichlorobenzyl methacrylate) is studied by broadband dielectric spectroscopy in the frequency range of and temperature interval of . The isotherms representing the dielectric loss of the glassy polymer in the frequency domain present a single ...
…, 2006
The relaxation behavior of poly(3-methylbenzyl methacrylate), poly(3-fluorobenzyl methacrylate), ... more The relaxation behavior of poly(3-methylbenzyl methacrylate), poly(3-fluorobenzyl methacrylate), and poly(3-chlorobenzyl methacrylate) was thoroughly studied by broadband dielectric spectroscopy with the aim of investigating the influence of slight differences in ...
Uploads
Papers by Gustavo Dominguez