Design and Simulation of InGaN -Junction Solar Cell

The tunability of the InGaN band gap energy over a wide range provides a good spectral match to sunlight, making it a suitable material for photovoltaic solar cells. The main objective of this work is to design and simulate the optimal InGaN single-junction solar cell. For more accurate results and best configuration, the optical properties and the physical models such as the Fermi-Dirac statistics, Auger and Shockley-Read-Hall recombination, and the doping and temperature-dependent mobility model were taken into account in simulations. The single-junction In 0.622 Ga 0.378 N (Eg = 1.39 eV) solar cell is the optimal structure found. It exhibits, under normalized conditions (AM1.5G, 0.1 W/cm 2 , and 300 K), the following electrical parameters: sc = 32.6791 mA/cm 2 , oc = 0.94091 volts, FF = 86.2343%, and = 26.5056%. It was noticed that the minority carrier lifetime and the surface recombination velocity have an important effect on the solar cell performance. Furthermore, the investigation results show that the In 0.622 Ga 0.378 N solar cell efficiency was inversely proportional with the temperature

Indirect techniques for astrophysical reaction rates determinations

Direct measurements of nuclear reactions of astrophysical interest can be challenging. Alternative experimental techniques such as transfer reactions and inelastic scattering reactions offer the possibility to study these reactions by using stable beams. In this context, I will present recent results that were obtained in Orsay using indirect techniques. The examples will concern various astrophysical sites, from the Big-Bang nucleo synthesis to the production of radioisotopes in massive stars

Study of 12C(α,γ)16O reaction via the transfer reaction 12C(7Li,t)16O

International audienceThe 12C(a,g )16O reaction plays an important role in helium burning in massive stars and their evolution. However, despite many experimental studies, the low-energy cross section of 12C(a,g )16O remains highly uncertain. The extrapolation of the measured cross sections to stellar energies (E=300 keV) is made difficult by the presence of the two sub-threshold states at 6.92 (2+) and 7.12 (1−) MeV of 16O. In order to further investigate the contribution of these twosubthreshold resonances to the 12C(a,g )16O cross section, we performed a new determination of the a-reduced widths of the 6.92 and 7.12 MeV of 16O via a measurement of the transfer reaction 12C(7Li,t)16O at two incident energies, 34 and 28 MeV. The measured and calculated differential cross sections are presented as well as the obtained spectroscopic factors and the a-reduced widths for the 2+ and 1− sub-threshold states and their effect on the R-matrix calculations of 12C(a,g )16O

Study of key resonances in the 30P(p,γ)31S reaction in classical novae

Among reactions with strong impact on classical novae model predictions, 30P(p,γ)31S is one of the few remained that are worthy to be measured accurately, because of their rate uncertainty, as like as 18F(p,α)15O and 25Al(pγ)26Si. To reduce the nuclear uncertainties associated to this reaction, we performed an experiment at ALTO facility of Orsay using the 31P(3He,t)31S reaction to populate 31S excited states of astrophysical interest and detect in coincidence the protons coming from the decay of the populated states in order to extract the proton branching ratios. After a presentation of the astrophysical context of this work, the current situation of the 30P(p,γ)31S reaction rate will be discussed. Then the experiment set-up of this work and the analysis of the single events will be presented

Study of the 26Al(n,p)26Mg and 26Al(n,α)23Na reactions using the 27Al(p,p')27Al inelastic scattering reaction

26Al was the first cosmic radioactivity ever detected in the galaxy as well as one of the first extinct radioactivity observed in refractory phases of meteorites. Its nucleosynthesis in massive stars is still uncertain mainly due to the lack of nuclear information concerning the 26Al(n,p)26Mg and 26 Al(n,α)23Na reactions. We report on a single and coincidence measurement of the 27Al(p,p')27Al(p)26Mg and 27Al(p,p')27Al(α)23Na reactions performed at the Orsay TANDEM facility aiming at the spectroscopy study of 27Al above the neutron threshold. Fourteen states are observed for the first time within 350 keV above the 26Al+n threshold

Patrimoine : voyage des mots. Heritage, Erbe, Beni culturali, Turâth, Tigemmi

International audienc

Patrimoine: voyages des mots. Heritage, Erbe, Beni culturali, Turâth, Tigemmi

Cette réflexion consacrée aux mots du patrimoine couvre plusieurs langues européennes et extra- européennes (français, anglais, allemand, italien, arabe, kabyle), tout en focalisant sur les années 1970 à nos jours, période de la montée en puissance en France de la notion de patrimoine et l’alignement de son sens à l’échelle mondiale. On favorisera une approche comparative par contraste afin de saisir les convergences et décalages d’un contexte à l’autre. L’entrée en la matière est toutefois vaste: elle peut être étymologique et linguistique, culturelle et sociologique, économique ou juridique. Ce dernier volet n’est pas à négliger car la mise en place de conventions internationales du patrimoine mondial, a posé comme langue principale de communication le français, mais a nécessité par la suite d’établir un lexique en plusieurs langues, faisant découvrir l’absence dans les cultures extra-européennes, africaine ou extrême-orientale par exemple, d’une terminologie équivalente. Cela ne veut pas dire que la notion de patrimoine y était inexistante mais qu’elle se présentait différemment. Il n’est pas aisé en effet de normaliser et de fixer un terme unique pour signifier une notion aussi étendue que celle de «patrimoine», autour de laquelle gravitent souvent d’autres notions liées à l’histoire et la mémoire, à l’identité culturelle, aux langues, à la dimension politique. Comment signifier une notion à travers des mots qui peuvent être réducteurs si l’on considère les multiples pratiques sociales et culturelles

Design and Simulation of InGaN p-n Junction Solar Cell

The tunability of the InGaN band gap energy over a wide range provides a good spectral match to sunlight, making it a suitable material for photovoltaic solar cells. The main objective of this work is to design and simulate the optimal InGaN single-junction solar cell. For more accurate results and best configuration, the optical properties and the physical models such as the Fermi-Dirac statistics, Auger and Shockley-Read-Hall recombination, and the doping and temperature-dependent mobility model were taken into account in simulations. The single-junction In0.622Ga0.378N (Eg = 1.39 eV) solar cell is the optimal structure found. It exhibits, under normalized conditions (AM1.5G, 0.1 W/cm2, and 300 K), the following electrical parameters: Jsc=32.6791 mA/cm2, Voc=0.94091 volts, FF = 86.2343%, and η=26.5056%. It was noticed that the minority carrier lifetime and the surface recombination velocity have an important effect on the solar cell performance. Furthermore, the investigation results show that the In0.622Ga0.378N solar cell efficiency was inversely proportional with the temperature

Treatment of artificial pharmaceutical wastewater containing amoxicillin by a sequential electrocoagulation with calcium salt followed by nanofiltration

International audienceThe present study deals with the treatment of an artificial pharmaceutical waste which contained amoxicillin (AMX) by using successively an electrocoagulation (EC) with Ca(NO3)2 as an electrolyte and a nanofiltration (NF) with a Nanomax-50 membrane. The effect of the current intensity and of the operating pressure was investigated for separately EC and NF, respectively. The AMX removal as a function of pH and initial AMX concentration was also investigated for the separately conducted EC and NF processes. The best percentage removal of AMX by EC and NF was recorded to be 52.7 % and 99.0 %, respectively. In the case of the sequential processes EC followed by NF, the removal of AMX was 98.2 % and 97.5 % at pH 2.5 and 10, respectively. The contribution of both EC and NF towards the AMX removal efficiency in the case of the sequential process was very much significant. It is remarkable that the EC pre-treated feed into NF was explored with several benefits such as high removal efficiency, calcium involved in EC process, prolonged membrane life and reduced power consumption. The electrogenerated solids (the sediment and the cathode deposit) were characterized using Fourier Transform Infra-red spectroscopy (FTIR), Energy Dispersive Spectroscopy (EDS) coupled to Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS) and Thermo Gravimetry Analysis (TGA). It appeared that calcium was involved in the electrogenerated solids. It gave a cathode deposit of Ca(OH)2 in which some AMX was embedded