Analysis of the Coupling Behavior of PEM Fuel Cells and DC-DC Converters

The connection between PEM fuel cells and common DC-DC converters is examined. The analysis is model-based and done for boost, buck and buck-boost converters. In a first step, the effect of the converter ripples upon the PEM fuel cell is shown. They introduce oscillations in the fuel cell. Their appearance is explained, discussed and possibilities for their suppression are given. After that, the overall behaviors of the coupled fuel cell-converter systems are analyzed. It is shown, that neither stationary multiplicities nor oscillations can be introduced by the couplings and therefore separate control approaches for both the PEMFC and the DC-DC converters are applicable

Orientation and distribution of recent gullies in the southern hemisphere of Mars: observations from HRSC/MEX and MOC/MGS data

Abstract not available

Ornithodoros quilinensis sp. nov. (Acari, Argasidae), a new tick species from the Chacoan region in Argentina

Ornithodoros quilinensis sp. nov. (Acari: Argasidae) is described from larvae collected on the small rodents Graomys centralis (Cricetidae: Sigmodontinae) in Argentina. The diagnostic characters for this new species are a combination of small size (520-540 μm), a dorsal plate oval in shape with a length of approximately 200 μm, 14 pairs of dorsal setae, hypostome short and narrower at the base (length from Ph1 to apex 133 μm (120-141)) with dental formula 2/2 and apex blunt, and the capsule of the Haller's organ irregular in shape and without reticulations. The analysis of the 16S rDNA sequences available for the genus Ornithodoros indicate that, phylogenetically, O. quilinensis represents an independent lineage only related to a Bolivian tick species of the genus Ornithodoros yet not formally described.Fil: Venzal, José M.. Universidad de la Republica, Salto; UruguayFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria Eea, Rafaela; ArgentinaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria Eea, Rafaela; ArgentinaFil: Mastropaolo, Mariano. Instituto Nacional de Tecnología Agropecuaria Eea, Rafaela; ArgentinaFil: Casás, Gustavo. UNIVERSIDAD DE LA REPUBLICA (UDELAR); . Universidad de la República; UruguayFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria Eea, Rafaela; Argentin