Search results for " mesurament"
showing 10 items of 23 documents
L-Band Vegetation optical depth and effective scattering albedo estimation from SMAP
2017
Abstract Over land the vegetation canopy affects the microwave brightness temperature by emission, scattering and attenuation of surface soil emission. Attenuation, as represented by vegetation optical depth (VOD), is a potentially useful ecological indicator. The NASA Soil Moisture Active Passive (SMAP) mission carries significant potential for VOD estimates because of its radio frequency interference mitigation efforts and because the L-band signal penetrates deeper into the vegetation canopy than the higher frequency bands used for many previous VOD retrievals. In this study, we apply the multi-temporal dual-channel retrieval algorithm (MT-DCA) to derive global VOD, soil moisture, and ef…
SMOS REFLEX 2003: L-band emissivity characterization of vineyards
2005
The goal of the Soil Moisture and Ocean Salinity mission over land is to infer surface soil moisture from multiangular L-band radiometric measurements. As the canopy affects the microwave emission of land, it is necessary to characterize different vegetation layers. This paper presents the Reference Pixel L-Band Experiment (REFLEX), carried out in June-July 2003 at the Vale/spl grave/ncia Anchor Station, Spain, to study the effects of grapevines on the soil emission and on the soil moisture retrieval. A wide range of soil moisture (SM), from saturated to completely dry soil, was measured with the Universitat Polite/spl grave/cnica de Catalunya's L-band Automatic Radiometer (LAURA). Concurre…
Experimental demonstration of the physics of resonant cavities
2005
We describe an undergraduate experiment that demonstrates the physics of cavity resonators. A mobile wall lets students alter the position of the nodes, thus changing the mode pattern. The nodal structure is made apparent by placing a metallic plate at different positions inside the cavity. A technique for dielectric characterization also is introduced, which helps students understand the boundary conditions in dielectrics, as well as highlighting the characteristics of fields in cavities.
Measurement of lifetimes in Fe-62,Fe-64, Co-61,Co-63, and Mn-59
2017
Lifetimes of the 4(1)(+) states in Fe-62,Fe-64 and the 11/2(1)(-) states in Co-61,Co-63 and Mn-59 were measured at the Grand Accelerateur National d'Ions Lourds (GANIL) facility by using the Advanced Gamma Tracking Array (AGATA) and the large-acceptance variable mode spectrometer (VAMOS++). The states were populated through multinucleon transfer reactions with a U-238 beam impinging on a Ni-64 target, and lifetimes in the picosecond range were measured by using the recoil distance Doppler shift method. The data show an increase of collectivity in the iron isotopes approaching N = 40. The reduction of the subshell gap between the nu 2p(1/2) and nu 1g(9/2) orbitals leads to an increased popul…
D-0-(D-0)over-bar mixing in the weak-gauged U(4)(L)circle times U(4)(R) chiral Lagrangian model
1998
The D-0- mixing is analyzed in a weak gauged U(4)(L) x U(4)(R) chiral lagrangian model where the electroweak interaction is introduced as a gauge theory over the meson degrees of freedom. This model allows a particular realization of the G.I.M. mechanism and then could be useful in the study of processes where G.I.M. suppression is effective. As a test of the model we have also analyzed the K-0- mixing. We find am, in good agreement with the experimental result and we show that the D-0- mixing is very much suppressed in agreement with previous estimates in the Heavy Quark expansion framework.
Design and Study of a Wide-Band Printed Circuit Board Near-Field Probe
2021
Magnetic near-field probes (NFP) represent a suitable tool to measure the magnetic field level from a small electromagnetic interference (EMI) source. This kind of antenna is useful as a magnetic field probe for pre-compliance EMC measurements or debugging tasks since the user can scan a printed circuit board (PCB) looking for locations with strong magnetic fields. When a strong H-field point is found, the designer should check the PCB layout and components placement in that area to detect if this could result in an EMI source. This contribution focuses on analyzing the performance of an easy to build and low-cost H-field NFP designed and manufactured using a standard PCB stack-up. Thereby,…
Quasi-digital conversion for resistive devices: application in GMR-based IC current sensors
2013
Resistive devices, including sensors, are used in a huge range of applications within different scenarios. When a complete system is considered, a quasi-digital output is often recommendable. If the conversion is operated at device level, some problems such as noise disturbs, insertion losses and so on, can be reduced. In this work, we describe a resistance-tofrequency (R-f) converter with a suggested application in low current monitoring by means of GiantMagnetoResistance (GMR) sensors. Specific devices have been designed and microfabricated. The system has been tested by means of discrete components with a PCB. The complete microsystem monolithic integration in a standard CMOS technology …
Construcció i validació d'instruments per avaluar competències genèriques, en educació superior
2019
espanolSe presenta una alternativa de evaluacion para las competencias genericas que se desarrolan en educacion superior, considerando su caracteristica de multidimensionalidad. Se construyen instrumentos para evaluar la dimension cognitiva, afectiva y conductual del pensamiento critico, comunicaciom, iniciativa emprendedora y trabajo en equipo y, responsabilidad social. Se analiza su validez de constructo, por medio del anaaisis factorial exploratorio y confiabilidad, a traves del calculo del coeficiente de consistencia interna –alfa de Cronbach– de una muestra de 493 estudiants de primer ano de carrera, durant 2015. Los resultados sugieren que se dispone de instrumentos confiables y va- l…
La contribución a la Década de la Educación por un Futuro Sostenible. Un compromiso ineludible para educadores e investigadores (Editorial)
2007
Vivimos una situación de auténtica emergencia planetaria , expresión acuñada por el biólogo Richard Bybee (1991) para llamar la atención sobre el conjunto de problemas de alcance global y estrechamente relacionados a los que la humanidad ha de hacer hoy frente. Una contaminación pluriforme y sin fronteras que envenena suelos, ríos y mares, hace irrespirable el aire y está provocando un acelerado cambio climático qué amenaza con hacer inhabitable nuestro planeta.
Measurements of the 90,91,92,94,96 Zr n, gamma cross-sections at n_TOF
2005
Neutron capture cross sections of the 90,91,92,94,96Zr have been measured over the energy range from 1 eV to 1 MeV at the spallation neutron facility n TOF at CERN in 2003. The innovative features of the neutron beam, in particular the high instantaneous flux, the high energy resolution and low background, together with improvements of the neutron sensitivity of the capture detectors make this facility unique for neutron-induced reaction cross section measurements with much improved accuracy. The preliminary results of the Zr measurements show capture resonance strengths generally smaller than in previous measurements. Peer Reviewed