In irrigation schemes under rotational water supply in semiarid region, the water allocation and irrigation scheduling are often based on a fixed-area proportionate water depth with every irrigation cycle irrespective...In irrigation schemes under rotational water supply in semiarid region, the water allocation and irrigation scheduling are often based on a fixed-area proportionate water depth with every irrigation cycle irrespective of crops and their growth stages, for an equitable water supply. An experiment was conducted during the 2004- 2005 season in Haouz irrigated area in Morocco, which objective was i) to evaluate the effects of the surface irrigation scheduling method (existing rule) adopted by the irrigation agency on winter wheat production compared to a full irrigation method and ii) to evaluate drip irrigation versus surface irrigation impacts on water saving and yield of winter wheat. The methodology was based on the FAO-56 dual approach for the surface irrigation scheduling. Ground measurements of the Normalized Difference Vegetation Index (NDVI) were used to derive the basal crop coefficient and the vegetation fraction cover. The simple FAO-56 approach was used for drip irrigation scheduling. For surface irrigation, the existing rule approach resulted in yield and WUE reductions of 22% and 15%, respectively, compared with the optimized irrigation scheduling proposed by the FAO-56 for full irrigation treatment. This revealed the negative effects of the irrigation schedules adopted in irrigation schemes under rotational water supply on crops productivity. It was also demon-strated that drip irrigation applied to wheat was more efficient with 20% of water saving in comparison with surface irrigation (full irrigation treatment). Drip irrigation gives also higher wheat yield compared to surface irrigation (+28% and +52% for full irrigation and existing rule treatments respectively). The same improvement was observed for water use efficiency (+24 and +59% respectively).展开更多
Considering the cosmological constantΛas a thermodynamic pressure and its conjugate quantity as a thermodynamic volume as proposed by Kubiznak and Mann[J.High Energy Phys.1207(2012)033],we discuss the critical behavi...Considering the cosmological constantΛas a thermodynamic pressure and its conjugate quantity as a thermodynamic volume as proposed by Kubiznak and Mann[J.High Energy Phys.1207(2012)033],we discuss the critical behavior of charged AdS black hole in arbitrary dimensions d.In particular,we present a comparative study in terms of the spacetime dimension d and the displacement of critical points controlling the transition between the small and the large black holes.Such behaviors vary nicely in terms of d.Our result shows that the equation of state for a charged Reissner–Nordstrom AdS black hole predicts an universal number given by(2d-5)/(4d-8).The three-dimensional solution is also discussed.展开更多
We reconsider the study of critical behaviors of Kerr—Newman Anti-de Sitter(AdS)black holes in four dimensions.The study is made in terms of the moduli space parameterized by the charge Q and the rotation parameter a...We reconsider the study of critical behaviors of Kerr—Newman Anti-de Sitter(AdS)black holes in four dimensions.The study is made in terms of the moduli space parameterized by the charge Q and the rotation parameter a,relating the mass M of the black hole and its angular momentum J via the relation a=J/M.Specifically,we discuss such thermodynamical behaviors in the presence of a positive cosmological constant considered as a thermodynamic pressure and its conjugate quantity as a thermodynamic volume.The equation of state for a charged Reissner—Nordstrom AdS black hole predicts a critical universal number depending on the(Q,a)moduli space.In the vanishing limit of the a parameter,this prediction recovers the usual universal number in four dimensions.Then,we find the bounded region of the moduli space allowing the consistency of the model with real thermodynamical variables.展开更多
This paper describes the design and simulation by HFSS simulator of a probe-fed Planar Inverted-F Antenna (PIFA) for the use in PCS band [1850 MHz - 1990 MHz]. A methodology based on parametric simulations (parameters...This paper describes the design and simulation by HFSS simulator of a probe-fed Planar Inverted-F Antenna (PIFA) for the use in PCS band [1850 MHz - 1990 MHz]. A methodology based on parametric simulations (parameters are ground plan dimensions, height of radiating plate, feeding point position, shorting plate dimensions and positioning) was used to design optimized antenna. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameter, resonant frequency, SWR, bandwidth impedance in feeding point, gain, 2D and 3D diagram pattern, Fields distribution. The simulation results are interesting and respect the mean PCS requirements.展开更多
This paper describes the design and simulation by HFSS simulator of a probe-fed and multi-band Planar Inverted-F Antenna (PIFA) for the 4G mobile networks. The antenna works in 8 bands. Five bands are auctioned by FCC...This paper describes the design and simulation by HFSS simulator of a probe-fed and multi-band Planar Inverted-F Antenna (PIFA) for the 4G mobile networks. The antenna works in 8 bands. Five bands are auctioned by FCC for 4G (LTE and WiMax) such 710 MHz, 1900 MHz (PCS), 2.3 GHz (WCS band), 3.65 GHz (rural 4G) and 5.8 GHz (FCC unlicensed band). The antenna allows working around 910 MHz ISM band. The GPS signal can be received in GPS L2 band around the frequency 1575 MHz. The antenna offers also a wideband around 8.62 GHz. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameters, resonant frequency, bandwidth, radiation efficiency, gain and diagram pattern. The results are very interesting and respect mostly the requirements.展开更多
The Van Hoof effect is a phase shift existing between the radial velocity curves of hydrogen and metallic lines within the atmosphere of pulsating stars.In this article,we present a study of this phenomenon through th...The Van Hoof effect is a phase shift existing between the radial velocity curves of hydrogen and metallic lines within the atmosphere of pulsating stars.In this article,we present a study of this phenomenon through the spectra of the brightest pulsating star RR Lyr of RR Lyrae stars recorded for 22 yr.We based ourselves,on the one hand,on 1268 spectra(41 nights of observation)recorded between the years 1994 and 1997 at the Observatory of Haute Provence(OHP,France)previously observed by Chadid and Gillet,and on the other hand on 1569 spectra(46nights of observation)recorded at our Oukaimeden Observatory(Morocco)between 2015 and 2016.Through this study,we have detected information on atmospheric dynamics that had not previously been detected.Indeed,the Van Hoof effect which results in a clear correlation between the radial velocities of hydrogen and those of the metallic lines has been observed and analyzed at different Blazhko phases.A correlation between the radial velocities of different metallic lines located in the lower atmosphere has been observed as well.For the first time,we were able to show that the amplitude of the radial velocity curves deduced from the lines of hydrogen and that of FeⅡ(λ4923.921?)increases toward the minimum of the Blazhko cycle and decreases toward the maximum of the same Blazhko cycle.Furthermore,we found that the Van Hoof effect is also modulated by the Blazhko effect.Thus,toward the minimum of the Blazhko cycle the Van Hoof effect is more visible and at the maximum of the Blazhko cycle,this effect is minimal.We also observed the temporal evolution of the amplitudes of the radial velocities of the lower and upper atmosphere.When observed over a long time,we can interpret it as a function of the Blazhko phases.展开更多
We study the Hawking radiation of 3D rotating hairy black holes. Specifically, we compute the transition probability of bosonic and fermionic particles in such backgrounds. Then, we show that the transition probabilit...We study the Hawking radiation of 3D rotating hairy black holes. Specifically, we compute the transition probability of bosonic and fermionic particles in such backgrounds. Then, we show that the transition probability is independent of the nature of the particle. It is observed that the charge of the scalar hairy B and the rotation parameter a control such a probability.展开更多
This paper describes a novel methodology to design PIFA (Planar Inverted-F Antenna) antennas based on parametric simulations. The parameters considered in the parametric design are ground plan dimensions, height of ra...This paper describes a novel methodology to design PIFA (Planar Inverted-F Antenna) antennas based on parametric simulations. The parameters considered in the parametric design are ground plan dimensions, height of radiating plate, feeding point position, shorting plate width and position. The choice of the parameters that must be varied independently or simultanously is important to design optimized antenna. The author studied two scenarios in precedent works [1,2]. He exposes here a third scenario of varing antenna parameters to design and simulate by HFSS (High Frequency Simulator Structure) simulator a probe-fed dual band PIFA for the use in GSM 850 band (824 MHz - 894 MHz) and PCS 1900 band (1850 MHz - 1990 MHz). The author compares the three scenarios and establishes a novel methodology to design optimized and miniaturized antennas mounted on mobile handsets.展开更多
This paper describes the design and simulation by HFSS simulator of a probe-fed Planar Inverted-F Antenna (PIFA) for the use in GSM900 band [890 MHz - 960 MHz] and DCS1800 band [1710 MHz - 1880 MHz]. A methodology bas...This paper describes the design and simulation by HFSS simulator of a probe-fed Planar Inverted-F Antenna (PIFA) for the use in GSM900 band [890 MHz - 960 MHz] and DCS1800 band [1710 MHz - 1880 MHz]. A methodology based on parametric simulations (parameters are ground plan lenght, height of radiating plate, feeding point position, shorting plate width and position) was used to design optimized antenna. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameter, resonant frequency, VSWR, bandwidth, impedance in feeding point, gain, diagram pattern and Fields distribution. The results were very interesting and respect the GSM requirements.展开更多
This paper describes the design and simulation by High Frequency Structure Simulator (HFSS) of a probe-fed Planar Inverted-F Antenna (PIFA) for the Ultra Wide Band (UWB) personal area networks. The slim antenna presen...This paper describes the design and simulation by High Frequency Structure Simulator (HFSS) of a probe-fed Planar Inverted-F Antenna (PIFA) for the Ultra Wide Band (UWB) personal area networks. The slim antenna presents a height of 2 mm and a bandwidth of more than 766 MHz. This bandwidth was improved by etching a U-slot in the antenna patch. The bandwidth offered then by the antenna is 839 MHz around the resonant frequency of 9 GHz. The improvement of bandwidth was accompanied by decreasing in gain and radiation efficiency. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameter, resonant frequency, bandwidth, radiation efficiency, gain and diagram pattern. The results are very interesting and respect the Federal Communications Commission (FCC) requirements.展开更多
This study aims at discussing longitudinal effects on the variability of the vertical E × B drift velocity at low latitudes, specifically over African sector. To this effect, observations from ground-based magnet...This study aims at discussing longitudinal effects on the variability of the vertical E × B drift velocity at low latitudes, specifically over African sector. To this effect, observations from ground-based magnetometers and the Ion Velocity Meter experiment onboard C/NOFS satellite are analyzed in conjunction with equatorial electric field and neutral wind model estimates under geomagnetically quiet conditions in the years 2012-2013. Notwithstanding the limitation in data over Africa, the combination of ground-based and in-situ observations confirmed the existence of longitudinal differences in the E × B between the Atlantic, Western and Eastern African sectors. This was well reproduced by the equatorial electric field model (EEFM) which showed that during noon, the peak of the equatorial electric field (EEF) was the lowest in the Atlantic sector, with an increasing trend towards the Eastern longitude. The Horizontal Wind Model 14 (HWM14) showed that the eastward zonal (poleward meridional) wind velocity was the lowest (highest) in the Eastern sector. Furthermore, the zonal (meridional) wind increased (decreased) from the Eastern to the Atlantic sector. These results highlight the contribution of the neutral wind velocity in driving the longitudinal difference in the vertical drift velocity over Africa.展开更多
文摘In irrigation schemes under rotational water supply in semiarid region, the water allocation and irrigation scheduling are often based on a fixed-area proportionate water depth with every irrigation cycle irrespective of crops and their growth stages, for an equitable water supply. An experiment was conducted during the 2004- 2005 season in Haouz irrigated area in Morocco, which objective was i) to evaluate the effects of the surface irrigation scheduling method (existing rule) adopted by the irrigation agency on winter wheat production compared to a full irrigation method and ii) to evaluate drip irrigation versus surface irrigation impacts on water saving and yield of winter wheat. The methodology was based on the FAO-56 dual approach for the surface irrigation scheduling. Ground measurements of the Normalized Difference Vegetation Index (NDVI) were used to derive the basal crop coefficient and the vegetation fraction cover. The simple FAO-56 approach was used for drip irrigation scheduling. For surface irrigation, the existing rule approach resulted in yield and WUE reductions of 22% and 15%, respectively, compared with the optimized irrigation scheduling proposed by the FAO-56 for full irrigation treatment. This revealed the negative effects of the irrigation schedules adopted in irrigation schemes under rotational water supply on crops productivity. It was also demon-strated that drip irrigation applied to wheat was more efficient with 20% of water saving in comparison with surface irrigation (full irrigation treatment). Drip irrigation gives also higher wheat yield compared to surface irrigation (+28% and +52% for full irrigation and existing rule treatments respectively). The same improvement was observed for water use efficiency (+24 and +59% respectively).
文摘Considering the cosmological constantΛas a thermodynamic pressure and its conjugate quantity as a thermodynamic volume as proposed by Kubiznak and Mann[J.High Energy Phys.1207(2012)033],we discuss the critical behavior of charged AdS black hole in arbitrary dimensions d.In particular,we present a comparative study in terms of the spacetime dimension d and the displacement of critical points controlling the transition between the small and the large black holes.Such behaviors vary nicely in terms of d.Our result shows that the equation of state for a charged Reissner–Nordstrom AdS black hole predicts an universal number given by(2d-5)/(4d-8).The three-dimensional solution is also discussed.
文摘We reconsider the study of critical behaviors of Kerr—Newman Anti-de Sitter(AdS)black holes in four dimensions.The study is made in terms of the moduli space parameterized by the charge Q and the rotation parameter a,relating the mass M of the black hole and its angular momentum J via the relation a=J/M.Specifically,we discuss such thermodynamical behaviors in the presence of a positive cosmological constant considered as a thermodynamic pressure and its conjugate quantity as a thermodynamic volume.The equation of state for a charged Reissner—Nordstrom AdS black hole predicts a critical universal number depending on the(Q,a)moduli space.In the vanishing limit of the a parameter,this prediction recovers the usual universal number in four dimensions.Then,we find the bounded region of the moduli space allowing the consistency of the model with real thermodynamical variables.
文摘This paper describes the design and simulation by HFSS simulator of a probe-fed Planar Inverted-F Antenna (PIFA) for the use in PCS band [1850 MHz - 1990 MHz]. A methodology based on parametric simulations (parameters are ground plan dimensions, height of radiating plate, feeding point position, shorting plate dimensions and positioning) was used to design optimized antenna. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameter, resonant frequency, SWR, bandwidth impedance in feeding point, gain, 2D and 3D diagram pattern, Fields distribution. The simulation results are interesting and respect the mean PCS requirements.
文摘This paper describes the design and simulation by HFSS simulator of a probe-fed and multi-band Planar Inverted-F Antenna (PIFA) for the 4G mobile networks. The antenna works in 8 bands. Five bands are auctioned by FCC for 4G (LTE and WiMax) such 710 MHz, 1900 MHz (PCS), 2.3 GHz (WCS band), 3.65 GHz (rural 4G) and 5.8 GHz (FCC unlicensed band). The antenna allows working around 910 MHz ISM band. The GPS signal can be received in GPS L2 band around the frequency 1575 MHz. The antenna offers also a wideband around 8.62 GHz. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameters, resonant frequency, bandwidth, radiation efficiency, gain and diagram pattern. The results are very interesting and respect mostly the requirements.
文摘The Van Hoof effect is a phase shift existing between the radial velocity curves of hydrogen and metallic lines within the atmosphere of pulsating stars.In this article,we present a study of this phenomenon through the spectra of the brightest pulsating star RR Lyr of RR Lyrae stars recorded for 22 yr.We based ourselves,on the one hand,on 1268 spectra(41 nights of observation)recorded between the years 1994 and 1997 at the Observatory of Haute Provence(OHP,France)previously observed by Chadid and Gillet,and on the other hand on 1569 spectra(46nights of observation)recorded at our Oukaimeden Observatory(Morocco)between 2015 and 2016.Through this study,we have detected information on atmospheric dynamics that had not previously been detected.Indeed,the Van Hoof effect which results in a clear correlation between the radial velocities of hydrogen and those of the metallic lines has been observed and analyzed at different Blazhko phases.A correlation between the radial velocities of different metallic lines located in the lower atmosphere has been observed as well.For the first time,we were able to show that the amplitude of the radial velocity curves deduced from the lines of hydrogen and that of FeⅡ(λ4923.921?)increases toward the minimum of the Blazhko cycle and decreases toward the maximum of the same Blazhko cycle.Furthermore,we found that the Van Hoof effect is also modulated by the Blazhko effect.Thus,toward the minimum of the Blazhko cycle the Van Hoof effect is more visible and at the maximum of the Blazhko cycle,this effect is minimal.We also observed the temporal evolution of the amplitudes of the radial velocities of the lower and upper atmosphere.When observed over a long time,we can interpret it as a function of the Blazhko phases.
文摘We study the Hawking radiation of 3D rotating hairy black holes. Specifically, we compute the transition probability of bosonic and fermionic particles in such backgrounds. Then, we show that the transition probability is independent of the nature of the particle. It is observed that the charge of the scalar hairy B and the rotation parameter a control such a probability.
文摘This paper describes a novel methodology to design PIFA (Planar Inverted-F Antenna) antennas based on parametric simulations. The parameters considered in the parametric design are ground plan dimensions, height of radiating plate, feeding point position, shorting plate width and position. The choice of the parameters that must be varied independently or simultanously is important to design optimized antenna. The author studied two scenarios in precedent works [1,2]. He exposes here a third scenario of varing antenna parameters to design and simulate by HFSS (High Frequency Simulator Structure) simulator a probe-fed dual band PIFA for the use in GSM 850 band (824 MHz - 894 MHz) and PCS 1900 band (1850 MHz - 1990 MHz). The author compares the three scenarios and establishes a novel methodology to design optimized and miniaturized antennas mounted on mobile handsets.
文摘This paper describes the design and simulation by HFSS simulator of a probe-fed Planar Inverted-F Antenna (PIFA) for the use in GSM900 band [890 MHz - 960 MHz] and DCS1800 band [1710 MHz - 1880 MHz]. A methodology based on parametric simulations (parameters are ground plan lenght, height of radiating plate, feeding point position, shorting plate width and position) was used to design optimized antenna. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameter, resonant frequency, VSWR, bandwidth, impedance in feeding point, gain, diagram pattern and Fields distribution. The results were very interesting and respect the GSM requirements.
文摘This paper describes the design and simulation by High Frequency Structure Simulator (HFSS) of a probe-fed Planar Inverted-F Antenna (PIFA) for the Ultra Wide Band (UWB) personal area networks. The slim antenna presents a height of 2 mm and a bandwidth of more than 766 MHz. This bandwidth was improved by etching a U-slot in the antenna patch. The bandwidth offered then by the antenna is 839 MHz around the resonant frequency of 9 GHz. The improvement of bandwidth was accompanied by decreasing in gain and radiation efficiency. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameter, resonant frequency, bandwidth, radiation efficiency, gain and diagram pattern. The results are very interesting and respect the Federal Communications Commission (FCC) requirements.
文摘This study aims at discussing longitudinal effects on the variability of the vertical E × B drift velocity at low latitudes, specifically over African sector. To this effect, observations from ground-based magnetometers and the Ion Velocity Meter experiment onboard C/NOFS satellite are analyzed in conjunction with equatorial electric field and neutral wind model estimates under geomagnetically quiet conditions in the years 2012-2013. Notwithstanding the limitation in data over Africa, the combination of ground-based and in-situ observations confirmed the existence of longitudinal differences in the E × B between the Atlantic, Western and Eastern African sectors. This was well reproduced by the equatorial electric field model (EEFM) which showed that during noon, the peak of the equatorial electric field (EEF) was the lowest in the Atlantic sector, with an increasing trend towards the Eastern longitude. The Horizontal Wind Model 14 (HWM14) showed that the eastward zonal (poleward meridional) wind velocity was the lowest (highest) in the Eastern sector. Furthermore, the zonal (meridional) wind increased (decreased) from the Eastern to the Atlantic sector. These results highlight the contribution of the neutral wind velocity in driving the longitudinal difference in the vertical drift velocity over Africa.
