Search results for "secondary [vertex]"
showing 10 items of 319 documents
A New Multipactor Effect Model for Dielectric-Loaded Rectangular Waveguides
2019
Multipactor is an electron discharge that may appear in particle accelerators and microwave devices such as filters, multiplexers, and RF satellite payloads in satellite on-board equipment under vacuum conditions. When some resonance conditions are satisfied, secondary electrons get synchronized with the RF fields, and the electron population inside the device grows exponentially leading to a multipactor discharge. This multipactor discharge has some negative effects that degrade the device performance: increase of signal noise and reflected power, heating of the device walls, outgassing, detuning of resonant cavities, and even the partial or total destruction of the component. The main aim…
Study of the Secondary Electron Yield in Dielectrics Using Equivalent Circuital Models
2018
[EN] Secondary electron emission has an important role on the triggering of the multipactor effect; therefore, its study and characterization are essential in radio-frequency waveguide applications. In this paper, we propose a theoretical model, based on equivalent circuit models, to properly understand charging and discharging processes that occur in dielectric samples under electron irradiation for secondary electron emission characterization. Experimental results obtained for Pt, Si, GaS, and Teflon samples are presented to verify the accuracy of the proposed model. Good agreement between theory and experiments has been found.
Reuse of urban-treated wastewater from a pilot-scale horizontal subsurface flow system in Sicily (Italy) for irrigation of Bermudagrass (Cynodon dact…
2016
Constructed wetlands (CW) are one of the most important biological technology for the treatment and reuse of wastewaters. The aim of this study was to evaluate the reuse of treated wastewater (TWW) from CW for irrigation of Bermudagrass turf (Cynodon dactylon (L.) Pers.) and assess the effects of TWW on the biometric and qualitative parameters of the turfgrass and on chemical–physical soil properties. The research was carried out in Sicily (Italy) in a pilot-scale horizontal subsurface flow system which was fed with urban TWW following secondary treatment from an activate sludge wastewater treatment plant. The pilot-system included three separate parallel units. The outflow TWW flowed downh…
Direct exposure to solar radiation causes radial growth eccentricity at the beginning of the growing season in Robinia pseudoacacia
2020
Abstract Our study investigated the effect of stem temperature increase on xylem formation in Robinia pseudoacacia tree-trunks, caused by direct exposure to solar radiation. It is important to determine factors which may improve the concentricity of deposited wood tissue and intensify xylogenesis because a strong irregularity of wood tissue deposited in the radial direction in mature trees of R. pseudoacacia reduces the commercial value of the wood. Samples of vascular cambium along with adjacent tissues were collected from the southern (illuminated) and northern (shaded) side of tree-trunks growing in the inner and peripheral (thus exposed to direct sunlight) zones of the research plot. Sa…
Integrating refugees into higher education – the impact of a new online education program for policies and practices
2018
Gaining access to higher education (HE) is a serious concern for refugees. Although studies on the integration and success of refugees in HE are scarce, the challenges associated with this issue as...
Unity Makes Strength: A Review on Mutualistic Symbiosis in Representative Insect Clades
2019
Settled on the foundations laid by zoologists and embryologists more than a century ago, the study of symbiosis between prokaryotes and eukaryotes is an expanding field. In this review, we present several models of insect–bacteria symbioses that allow for the detangling of most known features of this distinctive way of living, using a combination of very diverse screening approaches, including molecular, microscopic, and genomic techniques. With the increasing the amount of endosymbiotic bacteria genomes available, it has been possible to develop evolutionary models explaining the changes undergone by these bacteria in their adaptation to the intracellular host environment. The establishmen…
Universidad e Hispanidad. Tres décadas de trayectorias entrecruzadas del ministro José Ibáñez Martín y el catedrático exiliado Mariano Ruiz-Funes
2017
Presentamos la lucha desde el exilio intelectual republicano contra dos de las políticas del franquismo, la reforma de la universidad y la apropiación del término de hispanidad para los fines propagandísticos y proselitistas del nuevo régimen. Estas cuestiones son tratadas a partir de las trayectorias profesionales y vitales de dos políticos destacados, Mariano Ruiz-Funes y José Ibáñez Martín, desde sus inicios en la provincia de Murcia durante la década de 1920, en la cátedra de derecho penal uno y de enseñanza secundaria el otro, su militancia política, los servicios en misiones internacionales durante la guerra y, finalmente, la actividad de uno en la Unión de Profesores Universitarios E…
Quantification of propagating and standing surface acoustic waves by stroboscopic X-ray photoemission electron microscopy.
2018
The quantification of surface acoustic waves (SAWs) in LiNbO3 piezoelectric crystals by stroboscopic X-ray photoemission electron microscopy (XPEEM), with a temporal smearing below 80 ps and a spatial resolution below 100 nm, is reported. The contrast mechanism is the varying piezoelectric surface potential associated with the SAW phase. Thus, kinetic energy spectra of photoemitted secondary electrons measure directly the SAW electrical amplitude and allow for the quantification of the associated strain. The stroboscopic imaging combined with a deliberate detuning allows resolving and quantifying the respective standing and propagating components of SAWs from a superposition of waves. Furth…
El tratamiento de los phrasal verbs en los manuales de inglés lengua extranjera
2020
In this article we will study how phrasal verbs (PhVs) are dealt with in a representative sample of EFL student’s books of Secondary Education and Baccalaureate. From both a quantitative and qualitative point of view, the following aspects will be analysed: (i) whether PhVs are explicitly included into the index of each manual; (ii) whether there are any specific theoretical sections explaining their syntactic and semantic characteristics (and if so, what they consist of); (iii) whether there are any activities and/or exercises designed to practice and internalize these structures and, if any, to which methodological approach they attend; if any differences in the treatment of the PhVs may …
Innovations and Challenges: Conceptualizing CLIL Practice
2018
The continued emergence of content and language integrated learning (CLIL) is linked to how it creates, adopts, and leads to the design of innovative didactic processes. In systems, theory emergenc...