420 research outputs found
Silane modification of the flax/epoxy system interface
Natural fibres (NF) are normally subjected to pre-treatment to ensure good fibre to matrix bonding and consequent mechanical properties and durability. To enhance the sustainability of NF composite systems, it would be sensible to minimise processes that incur environmental burdens. This research considers that addition of silane coupling agent to epoxy resin hardener may be an alternative to the direct chemical pre-treatment of NF before composites manufacture. The current study indicates that silane-in-hardener can eliminate the pre-treatment of fibres and generates composites with optimum mechanical properties
THOMA C. COCHRAN YRUBÉN E. REINA, Entrepreneurship in' Argetine Culture. Torcuato Di Tella and S. 1. A. M (Philade1phia: University of Pennsylvania Press, 1962).
La construcciĂłn dentro de un sistema educativo de un mecanismo para la reforma y la innovaciĂłn continuas.
Resumen en español.Resumen en inglés
Calibration of QM-MOURA three-axis magnetometer and gradiometer
Abstract. MOURA instrument is a three-axis magnetometer and gradiometer designed and developed for Mars MetNet Precursor mission. The initial scientific goal of the instrument is to measure the local magnetic field in the surroundings of the lander i.e. to characterize the magnetic environment generated by the remanent magnetization of the crust and the superimposed daily variations of the field produced either by the solar wind incidence or by the thermomagnetic variations. Therefore, the qualification model (QM) will be tested in representative scenarios like magnetic surveys on terrestrial analogues of Mars and monitoring solar events, with the aim to achieve some experience prior to the arrival to Mars. In this work, we present a practical first approach for calibration of the instrument in the laboratory; a finer correction after the comparison of MOURA data with those of a reference magnetometer located in San Pablo de los Montes (SPT) INTERMAGNET Observatory; and a comparative recording of a geomagnetic storm as a demonstration of the compliance of the instrument capabilities with the scientific objectives
Elites in Latin América, edited by Seymour Martin Lipset and Aldo Solario (New York: Oxford University Press, 1967, pp. 531. $9.50).
Gamma Irradiation of Magnetoresistive Sensors for Planetary Exploration
A limited number of Anisotropic Magnetoresistive (AMR) commercial-off-the-shelf (COTS) magnetic sensors of the HMC series by Honeywell, with and without integrated front-end electronics, were irradiated with gamma rays up to a total irradiation dose of 200 krad (Si), following the ESCC Basic Specification No. 22900. Due to the magnetic cleanliness required for these tests a special set-up was designed and successfully employed. Several parameters of the sensors were monitored during testing and the results are reported in this paper. The authors conclude that AMR sensors without front-end electronics seem to be robust against radiation doses of up to 200 krad (Si) with a dose rate of 5 krad (Si)/hour and up to a resolution of tens of nT, but sensors with an integrated front-end seem to be more vulnerable to radiation
Peroxidase expression in a cereal cyst nematode (Heterodera avenae) resistant hexaploid wheat line.
The incompatible interaction between plant and pathogen is often determined by the hypersensitive reaction (HR). This response is associated with accumulation of reactive oxygen species (ROS), which results in adverse growth conditions for pathogens. Two major mechanisms involving either NADPH oxidases or peroxidases have been proposed for generation of ROS. Peroxidases (PER, EC 1.11.1.7), present in all land plants, are members of a large multigenic family with high number of isoforms involved in a broad range of physiological processes. PER genes, which are expressed in nematode feeding sites, have been identified in several plant species (Zacheo et al. 1997). A strong correlation between HR and PER activities at four and seven days post nematode infection, was detected in roots of wheat lines carrying Cre2, Cre5 (from Ae. ventricosa) or Cre7 (from Ae. triuncialis) Heterodera avenae resistance genes (Andrés et al. 2001; Montes et al. 2003, 2004). We have studied changes in root of peroxidase mRNAs levels after infection by H. avenae of a wheat/Ae. ven¬tricosa introgression line (H-93-8) carrying Cre2 (Delibes et al. 1993). We also report and classify the predicted protein sequences derived from complete peroxidase transcripts
El gĂ©nero Lysaphidus (Hymenoptera: Braconidae) en la PenĂnsula IbĂ©rica
The genus Lysaphidus Smith, 1944 (Hymenoptera, Braconidae, Aphidiinae) is recorded for the first time from the Iberian Peninsula represented by two species: L. arvensis Stary, 1960, first record for the Iberian Peninsula, and L. santolinae n. sp., both of them parasitoids of Coloradoa Wilson,1910 genus (Homoptera, Aphididae). The mummies were collected on Santolina chamaecyparissus L. and Santolina rosmarinifolia L. (Asteraceae).Se detecta la presencia del gĂ©nero Lysaphidus Smith, 1944 (Hymenoptera, Braconidae, Aphidiinae) en la PenĂnsula IbĂ©rica, representado por dos especies, L. arvensis Stary, 1960, nueva cita para la Peninsula IbĂ©rica y L. santolinae n. sp., parasitoides ambos del gĂ©nero Coloradoa Wilson, 1910 (Homoptera, Aphididae), cuyas momias fueron recolectadas sobre Santolina chamaecyparissus L. y Santolina rosmarinifolia L. (Asteraceae)
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