Search results for " technologies"
showing 10 items of 2721 documents
Existence of fixed point for GP(Λ;Θ)-contractive mappings in GP-metric spaces
2017
We combine some classes of functions with a notion of hybrid $GP_{(\Lambda,\Theta )}$ - $H$ - $F$ - contractive mapping for establishing some fixed point results in the setting of $GP$-metric spaces. An illustrative example supports the new theory.
Un estudio comparativo entre dos herramientas de respuesta de audiencia en las aulas universitarias
2019
El objetivo de este texto es investigar la influencia del uso de herramientas tecnológicas en las aulas universitarias. En concreto, analizamos y evaluamos la aplicación de dos herramientas de respuesta de audiencia libres (específicamente Socrative y Kahoot!) como herramientas que fomentan la participación y asistencia de los alumnos a las sesiones teóricas y facilitan el proceso de enseñanza-aprendizaje. Se analiza si estas herramientas pueden ser utilizadas como motivadoras, fomentadoras de la participación del alumnado y facilitadoras del aprendizaje. Además, la opinión de los estudiantes sobre la utilidad de estas herramientas en el aula y como métodos de enseñanza-aprendizaje. La mues…
Resistive communications based on neuristors
2017
Memristors are passive elements that allow us to store information using a single element per bit. However, this is not the only utility of the memristor. Considering the physical chemical structure of the element used, the memristor can function at the same time as memory and as a communication unit. This paper presents a new approach to the use of the memristor and develops the concept of resistive communication.
Melting temperature prediction by thermoelastic instability: An ab initio modelling, for periclase (MgO)
2021
Abstract Melting temperature (TM) is a crucial physical property of solids and plays an important role for the characterization of materials, allowing us to understand their behavior at non-ambient conditions. The present investigation aims i) to provide a physically sound basis to the estimation of TM through a “critical temperature” (TC), which signals the onset of thermodynamic instability due to a change of the isothermal bulk modulus from positive to negative at a given PC-VC-TC point, such that (∂P/∂V)VC,TC = -(∂2F/∂V2) VC,TC = 0; ii) to discuss the case of periclase (MgO), for which accurate melting temperature observations as a function of pressure are available. Using first princip…
The Acoustic Wave Behavior Within the PEA Cell for Space Charge Measurement
2018
In order to evaluate the acoustic wave behavior within the Pulsed Electro Acoustic (PEA) cell, a simulation model has been developed in this work. The model, implemented in Matlab environment, is based on the analogy between acoustic and electrical quantities. Therefore, it was possible to model the PEA cell as cascade connected lossy transmission lines. The model has been validated theoretically by making a comparison with a simulation result found in literature. The experimental validation has also been made by using the PEA cell of the LEPRE high voltage lab. In addition, four graphs have been realized. Two of them can be used to establish in easy and fast way to obtain the minimum groun…
Identification of parameters and harmonic losses of a deep-bar induction motor
2017
High frequency harmonics from a frequency converter causes additional losses in a deep-bar induction motor. The harmonics have their own amplitude and phase with respect to the fundamental signal, but the harmonic loss is only dependent on the amplitude of harmonics. A deep-bar induction motor can be modelled by a triple-cage circuit to take skin effect into account. The triple cage circuit having many parameters could be estimated from a small-signal model of the machine by using Differential Evolution. The correctly estimated parameters make the triple-cage circuit valid in a wide range of frequencies. However, the triple-cage circuit is very complicated which makes it difficult to model …
Investigation on partial discharges in HVDC cables after polarity reversal events
2020
Due to the accumulation of space charge inside the insulating layer of HVDC cables, the electric field under load conditions may be altered compared to what is established in HVAC cables. For example, a high thermal gradient leads to the inversion of the electric field pattern until the maximum value is reached in proximity of the dielectric-semicon interfaces. These maximum values can be further increased due to transient overvoltages and polarity reversal events until reaching electric field values higher than the rated ones. The main goal of this research is to investigate the possibility that, during these transient phenomena, conditions are created that favor the occurrence of partial …
Bathymetric estimation using MERIS images in coastal sea waters.
2007
Bathymetric estimation using remote sensing images has previously been applied to high spatial resolution imagery such as CASI, Ikonos, or SPOT but not on medium spatial resolution images (i.e., MERIS). This choice can be justified when there is a need to map the bathymetry on large areas. In this letter, we present the results of the bathymetry estimation over a large known area, the Gulf of Lion (France), expanding over 270times180 km
Intercomparison of Soil Moisture Retrieved from GNSS-R and from Passive L-Band Radiometry at the Valencia Anchor Station
2019
In this paper, the SOMOSTA (Soil Moisture Monitoring Station) experiment on the intercomparison of soil moisture monitoring from Global Navigation Satellite System Reflectometry (GNSS-R) signals and passive L-band microwave radiometer observations at the Valencia Anchor Station is introduced. The GNSS-R instrument has an up-looking antenna for receiving direct signals from satellites, and a dual-pol down-looking antenna for receiving LHCP (left-hand circular polarization) and RHCP (right-hand circular polarization) reflected signals from the soil surface. Data were collected from the three different antennas through the two channels of Oceanpal GNSS-R receiver and, in addition, calibration …
Assessment of the Potential Evapotranspiration MODIS Product Using Ground Measurements in the Pampas
2018
Evapotranspiration is the hydrological variable of greatest relevance in the Argentina Pampas Region (APR). The estimation of potential evapotranspiration (PET) in this area becomes essential since primary productivity is directly linked to water availability. In order to evaluate the MOD16_A2 product of evapotranspiration (ET), a comparison with in situ measurements was conducted. We used ET data provided by the Oficina de Riesgo Agropecuario, corresponding to 24 stations placed in the region covering all seasons for the years 2012 to 2014. Results show an overestimation of 86% and 52% in Autumn-Winter and Spring-Summer, respectively. Mean Absolut Error (MAE) range between ±0.9 and ±2.1 mm…