Rita Najjar

Lebanese University · Faculty of Science

Abandoned olive pruning residues (OLPR) are good source of carbon, an element required for the growth of Pleurotus ostreatus mushroom. The current study investigated the effect of implementation of olive pruning residues in oyster mushroom substrate. Based on mixtures of wheat straw (WS) (commercial control) and OLPR, four substrate types (treatmen...

Supplementation of the growing substrate affects the substrate temperature, the timing of consecutive harvests, and the production of oyster (Pleurotus ostreatus) mushroom. The study investigated the effect of two nitrogen-rich supplements, Lithovit®-Amino25 and Lithovit®-Urea50, added in two doses (3 or 5 g kg-1), once (at spawning or after first...

No previous study assessed the combined effect of olive pruning residues (OLPR) and spent coffee grounds (SCG) on P . ostreatus production and nutritional value. The aim of this study was to determine the capacity of P . ostreatus to degrade lignocellulosic nature of combined OLPR and SCG as well as their resultant nutrient composition. A complete...

Graphene aerogels (GAs) are amongst the lightest materials in the world. They attracted increasing interest in academia and industry because of their exceptional and unique properties, like high mechanical strength, electrical conductivity, thermal resistance, and adsorption capacity. In this review, we describe advances in research and development...

The Energy Efficiency Directive EED [1] defines the EU energy saving target as a maximum primary energy consumption (in Million Tone oil equivalent, Mtoe), that can be monitored with statistical data. Different energy savings methods can be used if data needed to measure the energy saving in an accurate manner are available (econometric models, bot...

Silver nanoparticles have been prepared using a “terminated gas condensation” technique. An unprecedented control of 5-6 nm-size nanoparticles with well defined shape and variable surface densities has been achieved. The technology is shown to permit independent control of both, plasmon resonance intensity and frequency position. On the basis of op...

Control of silver nanoparticles characteristics using a dedicated nano-clusters source and wavelength tuning of Plasmon resonance generated by small nanoparticles using different matrices. The results have been validated by advanced surface Plasmon modeling.

We evidence zero-dimensional exciton states trapped on isoelectronic Se centers in CdTe quantum wells, δ-doped with Se. Thanks to special precautions taken to have very high purity CdTe heterostructures, it is possible to observe, in photoluminescence spectra, sharp discrete lines arising from individual centers related to the Se doping. These emis...

Special growth conditions are presented in this work, in order to produce ZnTe/ZnSe type-II quantum dots and preserve them during the capping stage. A detailed study emphasizes the high sensitivity of the sample structure to Se/Zn ratio as opposed to other growth parameters. It is shown that nominally identical samples can evolve into two-dimension...

ZnTe/ZnSe type-II heterostructures interfaces were investigated versus growth conditions. A well controlled Se/Zn flux ratio allows us to control the structures type: quantum dots with excitonic recombination of around 5 ns photoluminescence decay time or a quantum well with spatially indirect recombination with a much longer decay close to 100 ns....

We present the photoluminescence and time resolved photoluminescence properties of an ensemble of ZnTe quantum dots embedded in a ZnSe matrix. Those heterostructures exhibit a type-II band alignment with holes confined within the dots and electrons kept in the close vicinity of the dots by coulomb attraction. We show that the structural and optical...

This work is based on the growth, by molecular beam epitaxy, of semiconductor heterostructures in which tellurium and selenium coexist. The goals are to develop optimized growth conditions and to study the specific physical properties due to this coexistence. More specifically, we worked on ZnTe/ZnSe type-II quantum wells and quantum dots, and on i...

We have performed a detailed study of the growth conditions of ZnTe strained on ZnSe to form nanometer-scale islands. We determined that the critical thickness for strain relaxation was 2 ML, rapidly followed by the onset of surface undulations due to a layer instability. Nevertheless, the changes in the surface morphology were not marked enough if...

During the growth of ZnTe by molecular beam epitaxy, we observed that, depending on the substrate temperature and flux ratio, the RHEED intensity oscillations can exhibit strong beats. Those beats are interpreted as a consequence of the coexistence, during growth, of c(2×2) and (2×1) surface reconstruction domains at the surface of (001)-ZnTe. The...

Ce travail repose sur le développement de la croissance, par épitaxie par jets moléculaires, d'hétérostructures présentant une alliance de deux familles de matériaux semi-conducteurs: les tellurures et les séléniures. Il tend à montrer l'originalité des propriétés physique spécifiques de cette association en développant deux cas: les puits et les b...

Self-assembled quantum dots (QDs) are of high interest for optical applications such as low-threshold lasers [1] or single sources for applications in quantum information processing [2,3]. It is well known, as demonstrated by a lot of groups, that the driving force for the islands formation is the strain relaxation between the two materials (Strans...