Production et transformation de la patate douce

Cultivée pour ses tubercules comestibles, la patate est une herbacée à tiges rampantes et volubiles pouvant atteindre 3 m de long. Facile à cultiver avec un cycle court, sa production est peu coûteuse et donne des rendements satisfaisants. Elle constitue un aliment idéal pour combattre la malnutrition. Le manuel décrit l’itinéraire technique à suivre pour la production améliorée de la patate douce. Il regorge d’informations pratiques sur sa transformation et sa consommation tout en mettant l’accent sur l’aspect nutritionnel de cette plante. Le lecteur y trouvera aussi des indications économiques et financières nécessaires pour la culture de cette plante à tubercules

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. Here, we introduce the molten-salt synthesis (MSS) method for making metal oxide nanomaterials. Advantages over other methods include its simplicity, greenness, reliability, scalability, and generalizability. Using pyrochlore lanthanum hafnium oxide (La2Hf2O7) as a representative, we describe the MSS protocol for the successful synthesis of complex metal oxide nanoparticles (NPs). Furthermore, this method has the unique ability to produce NPs with different material features by changing various synthesis parameters such as pH, temperature, duration, and post-annealing. By fine-tuning these parameters, we are able to synthesize highly uniform, non-agglomerated, and highly crystalline NPs. As a specific example, we vary the particle size of the La2Hf2O7 NPs by changing the concentration of the ammonium hydroxide solution used in the MSS process, which allows us to further explore the effect of particle size on various properties. It is expected that the MSS method will become a more popular synthesis method for nanomaterials and more widely employed in the nanoscience and nanotechnology community in the upcoming years

Excitation-Dependent Photoluminescence of BaZrO3:Eu3+ Crystals

The elucidation of local structure, excitation-dependent spectroscopy, and defect engineering in lanthanide ion-doped phosphors was a focal point of research. In this work, we have studied Eu3+-doped BaZrO3 (BZOE) submicron crystals that were synthesized by a molten salt method. The BZOE crystals show orange–red emission tunability under the host and dopant excitations at 279 nm and 395 nm, respectively, and the difference is determined in terms of the asymmetry ratio, Stark splitting, and intensity of the uncommon 5D0 → 7F0 transition. These distinct spectral features remain unaltered under different excitations for the BZOE crystals with Eu3+ concentrations of 0–10.0%. The 2.0% Eu3+-doped BZOE crystals display the best optical performance in terms of excitation/emission intensity, lifetime, and quantum yield. The X-ray absorption near the edge structure spectral data suggest europium, barium, and zirconium ions to be stabilized in +3, +2, and +4 oxidation states, respectively. The extended X-ray absorption fine structure spectral analysis confirms that, below 2.0% doping, the Eu3+ ions occupy the six-coordinated Zr4+ sites. This work gives complete information about the BZOE phosphor in terms of the dopant oxidation state, the local structure, the excitation-dependent photoluminescence (PL), the concentration-dependent PL, and the origin of PL. Such a complete photophysical analysis opens up a new pathway in perovskite research in the area of phosphors and scintillators with tunable properties. View Full-Tex

New Model for Discussing the Diffusion Phenomena Effect on a Thermoelastic Plate Associated With Three-phase Lag

Here, a new model was used to discuss the effect of a magnetic field on an isotropic, homogeneous, elastic material with generalized thermoelastic diffusion with two-temperature using a new technique. Most researchers in this domain discussed the behavior of the solution depending on two ways: the Laplace method and the normal mode method. Those two methods fail in explaining some of the physical meaning of the problems, especially the behavior of time. On the other hand, the separation of variables method solves the system of equations and gets the analytical solution directly. Copper material is used to discuss the results found in some magnetic field

Combining global and local semantic contexts for improving biomedical information retrieval

Présenté lors de l'European Conference on Information Retrieval 2011International audienceIn the context of biomedical information retrieval (IR), this paper explores the relationship between the document's global context and the query's local context in an attempt to overcome the term mismatch problem between the user query and documents in the collection. Most solutions to this problem have been focused on expanding the query by discovering its context, either \textit{global} or \textit{local}. In a global strategy, all documents in the collection are used to examine word occurrences and relationships in the corpus as a whole, and use this information to expand the original query. In a local strategy, the top-ranked documents retrieved for a given query are examined to determine terms for query expansion. We propose to combine the document's global context and the query's local context in an attempt to increase the term overlap between the user query and documents in the collection via document expansion (DE) and query expansion (QE). The DE technique is based on a statistical method (IR-based) to extract the most appropriate concepts (global context) from each document. The QE technique is based on a blind feedback approach using the top-ranked documents (local context) obtained in the first retrieval stage. A comparative experiment on the TREC 2004 Genomics collection demonstrates that the combination of the document's global context and the query's local context shows a significant improvement over the baseline. The MAP is significantly raised from 0.4097 to 0.4532 with a significant improvement rate of +10.62\% over the baseline. The IR performance of the combined method in terms of MAP is also superior to official runs participated in TREC 2004 Genomics and is comparable to the performance of the best run (0.4075)

New Model for Discussing the Diffusion Phenomena Effect on a Thermoelastic Plate Associated with Three-phase Lag

Here, a new model was used to discuss the effect of a magnetic field on an isotropic, homogeneous, elastic material with generalized thermoelastic diffusion with two-temperature using a new technique. Most researchers in this domain discussed the behavior of the solution depending on two ways: the Laplace method and the normal mode method. Those two methods fail in explaining some of the physical meaning of the problems, especially the behavior of time. On the other hand, the separation of variables method solves the system of equations and gets the analytical solution directly. Copper material is used to discuss the results found in some magnetic field

ELECTROCHEMICAL BEHAVIOR AND ANALYSIS OF MONURON HERBICIDE IN WATER USING VOLTAMMETRIC METHODS AND PRE ACTIVATED CARBON PASTE ELECTRODE

This research work dealt with the electrochemical behavior and voltammetric analysis of monuron, a phenyl urea herbicide. The sensitive enhancement of the monuron electrochemical signal, using a pre-activated carbon paste electrode, and the explanation of its mechanism were the main findings of this study. Unlike most used herbicides (linuron, diuron, fenuron, etc), monuron was rarely studied before by electrochemical methods. Indeed the square wave voltammetry allowed to optimize and to analyze monuron in water samples; the results showed two linear ranges of concentration: from 1.98 to 0.39 µg mL-1 and from 0.35 to 0.08 µg mL-1, with detection and quantification limits of LOD= 0.016 µg mL-1 and LOQ= 0.054µg mL-1 respectively. Besides these quantitative results, the anodic oxidation of monuron has been explained by an irreversible adsorption-controlled process, following a “one electron – one proton” mechanism

Spectrum of quenched twisted mass lattice QCD at maximal twist

Hadron masses are computed from quenched twisted mass lattice QCD for a degenerate doublet of up and down quarks with the twist angle set to pi/2, since this maximally twisted theory is expected to be free of linear discretization errors. Two separate definitions of the twist angle are used, and the hadron masses for these two cases are compared. The flavor breaking, that can arise due to twisting, is discussed in the context of mass splittings within the Delta(1232) multiplet.Comment: 23 pages, 16 figures, added discussion of pion decay constan

Samarium-Activated La2Hf2O7 Nanoparticles as Multifunctional Phosphors

Recent developments in the field of designing novel nanostructures with various functionalities have pushed the scientific world to design and develop high-quality nanomaterials with multifunctional applications. Here, we propose a new kind of doped metal oxide pyrochlore nanostructure for solid-state phosphor, X-ray scintillator, and optical thermometry. The developed samarium-activated La2Hf2O7 (LHOS) nanoparticles (NPs) emit a narrow and stable red emission with lower color temperature and adequate critical distance under near-UV and X-ray excitations. When the LHOS NPs are exposed to an energetic X-ray beam, the Sm3+ ions situated at the symmetric environment get excited along with those located at the asymmetric environment, which results in a low asymmetry ratio of Sm3+ under radioluminescence compared to photoluminescence. High activation energy and adequate thermal sensitivity of the LHOS NPs highlight their potential as a thermal sensor. Our results indicate that these Sm3+-activated La2Hf2O7 NPs can serve as a multifunctional UV, X-ray, and thermographic phosphor