Search results for "Energy engineering"
showing 10 items of 1099 documents
DC/DC converter topologies for electrolyzers: State-of-the-art and remaining key issues.
2017
In recent years, the use of electrolyzers to produce cleanly and efficiently hydrogen from renewable energy sources (i.e. wind turbines, photovoltaic) has taken advantage of a growing interest from researchers and industrial. Similarly to fuel cells, DC/DC converters are needed to interface the DC bus with the electrolyzer. Usually, electrolyzers require a low DC voltage to produce hydrogen from water. For this reason, a DC/DC buck converter is generally used for this purpose. However, other DC/DC converter topologies can be used depending on the feature of the electrolyzer and electrical grid as well. The main purpose of this paper is to present the current state-of-the-art of DC/DC conver…
Supplementary frequency regulation in non-synchronous AC system connected via MTDC
2019
Abstract In smart grid power system operation, frequency regulation is one of the most critical tasks towards power balance in the grid. This paper presents the schemes for improvement in operation of secondary loop of turbine-generator unit for frequency regulation in non-synchronous AC areas connected via multi-terminal direct current (MTDC) network. Two schemes have been discussed; (i) voltage droop based lead/lag compensator and (ii) DC power modulation at converter terminal depending upon frequency deviation from each AC area. In the first scheme, droop design based on lead/lag compensator using DC voltage deviation is introduced as supplementary signal at turbine-generator unit in eac…
Characterization of clamp-on current transformers under nonsinusoidal conditions
2009
This paper reports the performance of clamp-on current transformers under nonsinusoidal conditions. A set of experimental measurements helped to determine the ratio and the phase errors under two conditions: 1) sinusoidal excitation with frequencies from 45 to 1000 Hz and 2) nonsinusoidal excitation using the fundamental frequency and one harmonic, with adjusted phase shift. It was found that ratio and phase errors are affected by the phase angle between the harmonic and the fundamental and the harmonic amplitude. The effects of conductor location in the current transformer's window and of the air-gap width were also investigated. It was concluded that harmonic phase and ratio errors measur…
Atrofia muscular espinal y bulbar Enfermedad de Kennedy. Aspectos clínicos y genéticos
2019
La atrofia muscular espinal y bulbar es una enfermedad neurologica caracterizada por degeneracion gradual de la motoneurona inferior, que resulta en debilidad muscular, atrofia y fasciculaciones. Es una entidad de etiologia genetica con mecanismo de herencia ligado al cromosoma X recesivo, por lo que afecta a varones, en la que se produce una expansion del triplete CAGn en el gen del receptor de androgenos. Se manifiesta por signos de insensibilidad a los androgenos (ginecomastia e infertilidad). A partir de los 20-30 anos, aproximadamente, comienzan los signos de afectacion de la motoneurona inferior a nivel espinal con calambres y temblor de accion y posteriormente debilidad muscular. En …
“ABORDAJES. SOBRE COMUNICACIÓN Y CULTURA”
2020
“IMÁGENES DESCARNADAS. CUERPO, POLÍTICA E IMAGINACIÓN”
2020
Video Art by Mexican Women Artists in the 21st Century. Context and Dissemination
2015
The new art history arises, from an interdisciplinary view, theoretical and practical embodiment issues related with contemporary art and its inclusion and development in university world. At the same time,gender studies have been incorporated into the development of postgraduate curriculum, placing value on the art work of women, continuing the contestation to the canon already started in the twentieth century. These gender discourses have assumed new technologies as the most versatile media format with unlimited field for image dissemination. Consequently, in the context of globalization, the intangible and digitalformats have become priority means when developing feminist and post-femini…
Interesterification of triglycerides with methyl acetate for biodiesel production using a cyclodextrin-derived SnO@γ-Al2O3 composite as heterogeneous…
2022
International audience; Particle morphology and surface properties of metal oxides are topics of great importance in the field of heterogeneous catalysis. Herein, we have developed a molecular-colloidal coassembly approach combined with an ultrasonic-assisted precipitation method to fabricate SnO@γ-Al2O3 composites with tuneable pore size and well-defined octahedral-shape crystal structure. The supramolecular assemblies formed between the randomly methylated β-cyclodextrin (RaMeβCD) and Pluronic F127 were employed as template to tailor the size and shape of γ-Al2O3 nanoparticles and direct their assembly almost exclusively on the surface of micrometer-sized SnO single …
WITHDRAWN: Perspective on hydrogen energy carrier and its automotive applications
2013
Assessing the quality of the sampling of fuel peat using computer simulation
1995
A simulation scheme to assess and improve the performance of the sampling of fuel peat is considered. The scheme provides a practical possibility to inspect all possible sources of variation and error. Test results from a district heating plant are reported.