Challenges, opportunities, and solutions for converged satellite and terrestrial networks

International audienceThe current trend in telecommunications services provisioning is shifting toward global ubiquitous networking and unified service architecture. Given the diversity of access technologies, this global ubiquitous networking cannot be possible without efficient interworking between the different access players. This leads to the necessity of defining, implementing, and deploying common services control architecture, able to support a wide variety of services for users in a variety of roles (consumer, producer, or manager of communication and media). This article defines some issues related to the interworking operation between the satellite and terrestrial domains. It suggests some solutions and discusses their potential

Efficiency of a Pretreatment by Electrocoagulation with Aluminum Electrodes in a Nanofiltration Treatment of Polluted Water

International audienceThe decrease of quality and availability of waters induces the research of hyphenated technologies for improving purification processes. The paper is devoted to the water treatment of a lack which accumulates a diversified pollution arising from a lot of industries. The investigated lack water contained heavy metals, fecal bacteria and high chemical pollution as measured by its chemical oxygen demand (COD). An electrocoagulation was applied as water pretreatment of a nanofiltration process. The electrocoagulation was carried out in a batch experiment with two parallel aluminum plates of 15 cm2. Water analysis showed a decrease of the COD from 60 to 5 mg L-1, depending upon current density, current charge and solution pH. Thanks to electrocoagulation efficiency, the most probable number (MPN) of bacteria decreased from 2500 to 2 MPN/100 mL. This disinfection allowed the performing of a continuous coupling treatment of electrocoagulation and nanofiltration by using a cylindrical aluminum anode and an organic Nanomax50 membrane respectively

A new spectral index for the extraction of built-up land features from Landsat 8 satellite imagery

Extracting built-up areas from remote sensing data like Landsat 8 satellite is a challenge. We have investigated it by proposing a new index referred as Built-up Land Features Extraction Index (BLFEI). The BLFEI index takes advantage of its simplicity and good separability between the four major component of urban system, namely built-up, barren, vegetation and water. The histogram overlap method and the Spectral Discrimination Index (SDI) are used to study separability. BLFEI index uses the two bands of infrared shortwaves, the red and green bands of the visible spectrum. OLI imagery of Algiers, Algeria, was used to extract built-up areas through BLFEI and some new previously developed built-up indices used for comparison. The water areas are masked out leading to Otsu’s thresholding algorithm to automatically find the optimal value for extracting built-up land from waterless regions. BLFEI, the new index improved the separability by 25% and the accuracy by 5%.open access</p

Chlorophyll a–violaxanthin interactions in monolayers at air–water interface and in Langmuir–Blodgett films

Short distance interactions of chlorophyll a with violaxanthin (Viol) were studied in monolayers at the air-water interface and in Langmuir-Blodgett films. The surface pressure–area ( π– A) isotherms for Chl a, Viol, and Chl a–Viol mixtures clearly indicate the formation of two types of complexes between Chl a and Viol with the stoichiometric ratios of 2:1 and 1:1. The complexes formed between Chl a and Viol are reflected by the changes in molecular organization of Viol in monolayers. As the fluorescence properties of Chl a molecules are known to be strongly dependent on changes in the degree of its aggregation, we followed the changes in fluorescence at different molar ratios. The molecular aggregations are noticed by the changes in band intensities at 683 and 730 nm in fluorescence emission spectra and an increase in the relative intensity of fluorescence short lifetime component of Chl a. Chl a–Viol interactions in monolayers were also made clear by the analysis of the shortwave region of the photoacoustic spectra explaining very efficient singlet-singlet excitation energy transfer from caratenoid to Chl a. Further, Chl a–Viol interactions and modeling of the formation of the complexes were also discussed based on the FTIR spectra of pure components as well as mixed systems