Search results for "Solai"

"Mettre le soleil en bouteille" : les appareils de Mouchot et l'imaginaire solaire au début de la troisième République

2010

International audience; Dans l’imaginaire commun, le XIXe siècle reste associé au charbon. Le mineur incarne la figure du prolétaire et la machine à vapeur symbolise la révolution industrielle. Pourtant, on sait que cette prépondérance du charbon ne fut jamais totale, l’énergie hydraulique subsiste durablement et de multiples autres trajectoires technologiques et énergétiques ont été expérimentées. Au début de la Troisième République, alors que le régime s’appuie sur la science et la technique, un bref moment d’exaltation de l’énergie solaire et de ses possibilités d’avenir voit ainsi le jour. Devant la crainte de l’épuisement des gisements de houille, face à l’expansion impériale et aux né…

Sonnenbarke und zyklisches Weltbild. Überlegungen zum Verständnis der spätbronzezeitlichen Ikonographie in Mitteleuropa

2005

International audience

Development of Kesterite (Cu2ZnSnS4) absorber material for solar cell application.

2021

Kesterite-based solar cells still suffer from limited efficiency due to various problems related to the absorber and device interfaces. Absorber defects and non-ideal band alignment at the absorber/buffer hetero-interface, resulting in a cliff-like conduction band offset (CBO), and non-ideal absorber/back contact interfaces are the main factors limiting efficiency.This thesis focuses mainly on the absorber-related problems such as the secondary phases and the band alignment at the absorber-buffer heterojunction as well as the back interface.In the first part, the properties of the absorber layer were studied. Thin layers of Cu2ZnSnS4 (CZTS) were obtained by chemical route. This study reveal…

Timing and patterns of the ENSO signal in Africa over the last 30 years: insights from normalized difference vegetation index data.

2014

Abstract A more complete picture of the timing and patterns of the ENSO signal during the seasonal cycle for the whole of Africa over the three last decades is provided using the normalized difference vegetation index (NDVI). Indeed, NDVI has a higher spatial resolution and is more frequently updated than in situ climate databases, and highlights the impact of ENSO on vegetation dynamics as a combined result of ENSO on rainfall, solar radiation, and temperature. The month-by-month NDVI–Niño-3.4 correlation patterns evolve as follows. From July to September, negative correlations are observed over the Sahel, the Gulf of Guinea coast, and regions from the northern Democratic Republic of Congo…

I solai latero-cementizi ed il metodo semiprobabilistico agli stati limite

2012

I principali riflessi del metodo semiprobabilistico agli stati limite nel progetto dei solai laterocementizi

2008

Solai in legno e gesso - sperimentazioni

2010

Synthesis of oligomers and polymers doped with porphyrins for solar energy conversion

2017

The aim of this thesis was to elaborate new electron donor materials for organic solarcells. This emerging photovoltaic technology is rapidly expanding, and has yet already reached the limit for its large-scale commercialization. The low manufacturing cost of organic photovoltaic devices make then competitive face to well-established inorganic technologies. Their biggest advantage is their weight and their mechanical properties which make them flexible. They should play a key role in future as a complement to classic solar cells, with their use in specific applications. We developed polymers by using different chomophores, well-known for their interesting photophysical properties: the porph…

Etude numérique du comportement thermique d’un séchoir solaire utilisant un lit thermique pour le stockage d’énergie

2018

This thesis presents a numerical study of an indirect natural convection solar dryer for drying agricultural products (Figs). The first part analyzes a solar dryer containing a drying chamber coupled to a reversed absorber and a solar chimney. Simulations were made to determine the dynamic and thermal fields under the influence of the variation of the solar chimney configuration and the size of the inlet opening. The governing equations based on the standard k-ε turbulence model are solved by the finite volume method using the ANSYS-Fluent commercial code. The second part analyzes the effect of adding a thermal storage in the form of a gravel bed in the drying chamber. The bed is modeled as…

Analysis of cloudiness and solar radiation diurnal cycles for a better understanding of the forests greenness mean annual cycle in Central Africa.

2016

To better understand the Central Africa forests sensitivity toclimate variability, we jointly analyse the mean annual cycles of greenness, rainfall, cloudiness and solarradiation for the target region 0-5°N/12-19°E using high resolution satellite data. Our results demonstrate theimportance of the diurnal scale for understanding the mean annual cycles of rainfall, cloudiness and solarradiation and the way they shape those of forest greenness. They also suggest that whereas the March-Mayrainy season appears optimal for greenness especially because of favorable light conditions, water availabilityis the main controlling factor in December-January the main dry season and in February at the star…