3,865 research outputs found
Assessment of nutrient entry pathways and dominating hydrological processes in lowland catchments
International audienceThe achievement of a good water quality in all water bodies until 2015 is legally regulated since December 2000 for all European Union member states by the European Water Framework Directive (EU, 2000). The aim of this project is to detect nutrient entry pathways and to assess the dominating hydrological processes in complex mesoscale catchments. The investigated Treene catchment is located in Northern Germany as a part of a lowland area. Sandy, loamy and peat soils are characteristic for this area. Land use is dominated by agriculture and pasture. Drainage changed the natural water balance. In a nested approach we examined two catchment areas: a) Treene catchment 517 km2, b) Kielstau catchment 50 km2. The nested approach assists to improve the process understanding by using data of different scales. Therefore these catchments serve not only as an example but the results are transferable to other lowland catchment areas. In a first step the river basin scale model SWAT (Soil and Water Assessment Tool, Arnold et al., 1998) was used successfully to model the water balance. Furthermore the water quality was analysed to distinguish the impact of point and diffuse sources. The results show that the tributaries in the Kielstau catchment contribute high amounts of nutrients, mainly nitrate and ammonium. For the parameters nitrate, ammonium and phosphorus it was observed as a tendency that the annual loads were increasing along the river profile of the Kielstau
Mini-garfagem: um novo metodo para a enxertia do mogno sul-americano (Swietenia macrophylla King).
bitstream/CNPF-2009-09/30404/1/com_tec62.pd
Static quantities of a neutral bilepton in the 331 model with right-handed neutrinos
A neutral vector boson can possess static electromagnetic properties provided
that the associated field is no self-conjugate. This possibility is explored in
the model with right-handed neutrinos, which
predicts a complex neutral gauge boson in a nontrivial representation of
the electroweak group. In this model the only nonvanishing form factors are the
CP-even ones, which arise from both the quark and gauge sectors, and contribute
to the magnetic dipole and the electric quadrupole moments of this neutral
particle.Comment: 10 pages, 6 figures, submitted to Phys. Rev.
Out-of-phase oscillation between superfluid and thermal components for a trapped Bose condensate under oscillatory excitation
The vortex nucleation and the emergence of quantum turbulence induced by
oscillating magnetic fields, introduced by Henn E A L, et al. 2009 (Phys. Rev.
A 79, 043619) and Henn E A L, et al. 2009 (Phys. Rev. Lett. 103, 045301), left
a few open questions concerning the basic mechanisms causing those interesting
phenomena. Here, we report the experimental observation of the slosh dynamics
of a magnetically trapped Rb Bose-Einstein condensate (BEC) under the
influence of a time-varying magnetic field. We observed a clear relative
displacement in between the condensed and the thermal fraction center-of-mass.
We have identified this relative counter move as an out-of-phase oscillation
mode, which is able to produce ripples on the condensed/thermal fractions
interface. The out-of-phase mode can be included as a possible mechanism
involved in the vortex nucleation and further evolution when excited by time
dependent magnetic fields.Comment: 5 pages, 5 figures, 25 reference
Use of low-cost class a evapotranspiration pan for reference evapotranspiration estimation in protected and field environments.
Currently, there are various methods for determining the Class A pan coefficient (Kp) in estimating reference evapotranspiration (ETo), which is of utmost importance for water management in agriculture. This study aimed to estimate ETo inside and outside agricultural greenhouses using a low-cost constructed Class A pan (TCA-c) method. To estimate ETo, it is necessary to establish the Kp, as ETo is the product of ECA multiplied by Kp. This study employed the calibration method, comparing ETo determined by Penman-Monteith (EToPM) with Class A pan evaporation (ECA) to determine Kp. EToPM served as the standard for correlations with reference evapotranspiration using the TCA-c method inside and outside an agricultural greenhouse, avoiding the installation of a "Class A" pan inside the greenhouse. The experiment was conducted at UFF's Gragoatá campus in Niterói - RJ. Four TCA-c pans were installed (three inside and one outside an agricultural greenhouse) and managed for one year. Principal Component Analyses (PCA) revealed significant differences in ETo throughout the seasons. Adjusted Kps were established for all pans. It was observed that ETo inside the greenhouse was lower than that estimated outside. It is recommended to install the TCA-c pan inside the greenhouse for ETo estimation, utilizing different Kps throughout the seasons
Generalized LUI propagation model for UAVs communications using terrestrial cellular networks
This work proposes an empirical propagation model to obtain the path loss and therefore determine the average received power of a signal for a specific outdoor urban scenario with UAVs. The proposed 3D propagation model for terrestrial cellular networks generalizes the LUI model and is valid in the frequency ranges of GSM, UMTS and LTE technologies. We report experimental work in 3D space, considering the height, the antennas base station tilt, sectorziation, angle and distances profile The experimental work included in this study is in good agreement with the proposed theoretical model, corroborating the idea that this model is a good contribution for cellular planning tools.info:eu-repo/semantics/acceptedVersio
Fermion contribution to the static quantities of arbitrarily charged vector bosons
We present an analysis of the one-loop contribution from left- and
right-handed fermions to the static electromagnetic properties of an
arbitrarily charged no self-conjugate vector boson . Particular emphasis is
given to the case of a no self-conjugate neutral boson . Regardless the
electric charge of the boson, a fermionic loop can induce the two CP-even
form factors but only one CP-odd. As a result the corresponding electric dipole
moment is directly proportional to the magnetic quadrupole moment. The CP-odd
form factor might be severely suppressed since it requires the presence of both
left- and right-handed fermions. The behavior of the form factors is analyzed
for several scenarios of the fermion masses in the context of the decoupling
theorem.Comment: 12 pages, 3 figures, submitted to Journal of Physics
Alkali activation of recycled ceramic aggregates from construction and demolition wastes
Environmental concerns are becoming increasingly more significant worldwide, thus creating the urgent need for new sustainable alternatives in the industrial sector. The present study assesses the fundamental properties of ceramic residue (CR) originated by demolition operations, specifically, the floor and wall tiles and sanitaryware furniture, for further incorporation in the construction sector, namely in alkali-activated bind- ers, mixed with other better-known precursors - fly ash (FA) and ladle furnace slag (LFS). Different CR/FA and CR/LFS weight ratios were considered and analyzed by mechanical behavior and microstructural analysis, which included uniaxial compression strength (UCS) tests, Scanning Electron Microscopy (SEM), X-ray Energy Dispersive Analyser (EDX), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Results obtained showed that the combination of CR and FA or LFS, activated with sodium silicate, produced UCS values higher than 20 MPa and 59 MPa, respectively, after 90 days curing.Activación alcalina de áridos cerámicos reciclados provenientes de residuos de construcción y
demolición. Globalmente, las preocupaciones ambientales son cada vez más significativas, creando así la necesidad urgente de nuevas alternativas sostenibles en el sector industrial. El presente estudio evalúa las propiedades
fundamentales de los residuos cerámicos (CR) provenientes de demolición, para ser reincorporados en el sector
de la construcción, principalmente como ligantes activados alcalinamente, mezclados con otros precursores más
conocidos: cenizas volantes (FA) y escorias de horno de cuchara (LFS). Se consideraron diferentes relaciones
de peso CR/FA y CR/LFS, se analizó el comportamiento mecánico y se realizó un análisis microestructural,
incluyendo pruebas de resistencia a la compresión (UCS), microscopía electrónica de barrido (SEM), análisis
por energías dispersivas de rayos X (EDX), Rayos-X (XRD) y espectroscopía infrarroja por transformada de
Fourier (FTIR). Los resultados mostraron que, a 90 días de curado, la combinación de CR y FA o LFS activada
con silicato de sodio produjo valores de UCS superiores a 20 MPa y 59 MPa, respectivamenteFoundation for Science and Technology - FCT/MCTES (PIDDAC), within the framework of the R&D Project “JUSTREST - Development of Alkali Binders for Geotechnical Applications Made Exclusively from Industrial Waste”, reference PTDC/ECM-GEO/0637/2014. The author would also like to acknowledge the support of the Secretary of Higher Education, Figure 8. FTIR spectra of starting materials, the ladle furnace slag (LFS); ceramic residue (MCR) – milled for 32 hours; fly ash (FA), and 75CR-25FA/SH or SS mixtures (M1 and M2) and 75CR-25LFS/SH or SS mixtures (M3 and M4), after 90 days curing time. Science, Technology and Innovation, SENESCYT (Spanish acronym) from Ecuador, reference No.
CZ03-000052-201
Low-cost class a evapotranspiration pan for reference evapotranspiration estimation in protected and field environments: a practical approach.
Currently, there are various methods for determining the Class A pan coefficient (Kp) in estimating reference evapotranspiration (ETo), which is of utmost importance for water management in agriculture. This study aimed to estimate ETo inside and outside agricultural greenhouses using a low-cost constructed Class A pan (TCA-c) method. To estimate ETo, it is necessary to establish the Kp, as ETo is the product of ECA multiplied by Kp. This study employed the calibration method, comparing ETo determined by Penman-Monteith (EToPM) with Class A pan evaporation (ECA) to determine Kp. EToPM served as the standard for correlations with reference evapotranspiration using the TCA-c method inside and outside an agricultural greenhouse, avoiding the installation of a "Class A" pan inside the greenhouse. The experiment was conducted at UFF's Gragoatá campus in Niterói - RJ. Four TCA-c pans were installed (three inside and one outside an agricultural greenhouse) and managed for one year. Principal Component Analyses (PCA) revealed significant differences in ETo throughout the seasons. Adjusted Kps were established for all pans. It was observed that ETo inside the greenhouse was lower than that estimated outside. It is recommended to install the TCA-c pan inside the greenhouse for ETo estimation, utilizing different Kps throughout the seasons
- …