Modeling and synthesis of carbon-coated LiMnPO4 cathode material: Experimental investigation and optimization using response surface methodology

Nanostructured LiMnPO4 cathode materials for lithium-ion batteries (LIBs) have been successfully prepared by a modified solvothermal method under controlled conditions. Polyethylene glycol (PEG-10000) was used as a solvent to optimize the particle size/mor­phology and as a carbon conductive matrix. In order to investigate the effect of synthesis parameters such as concentration of PEG-10000, reaction time and reaction temperature on the LiMnPO4 phase purity, Response surface methodology was carried out to find variations in purity results across the composition. The purity of all materials was checked using HighScore software by comparing the matched lines score to ones of reference data. As a result, it has been found that the pure phospho-olivine material LiMnPO4 can be syn­thesized using the following optimum conditions: PEG concentration = 0.1 mol l-1, reaction time = 180 min, and reaction temperature = 250 °C. The as-prepared LiMnPO4 under opti­mum conditions delivered an initial discharge capacity of 128.8 mAh g-1 at 0.05 C‑rate. The present work provides insights and suggestions for optimizing synthesis conditions of this material, which has been considered the next promising cathode candidate for high-energy lithium-ion batteries

Embryonic paratesticular rhabdomyosarcoma: a case report

INTRODUCTION: An embryonic paratesticular rhabdomyosarcoma is a very rare mesenchymal tumor. It is an intrascrotal tumor that is localized in paratesticular structures such as the epididymis or spermatic cord. Rhabdomyosarcoma is most often observed in children and adolescents, presenting as a painless scrotal mass. CASE PRESENTATION: Our patient was an 18-year-old Moroccan man who presented with a painless left scrotal mass that had evolved over four months. An inguinal orchiectomy was performed. A histological examination of the excised tissue revealed an embryonic rhabdomyosarcoma. Our patient had three sessions of chemotherapy with vincristine, actinomycin C and cyclophosphamide. Each chemotherapy session was conducted over five days, with a cycle of 21 days. Our patient was assessed two months after the last chemotherapy session and demonstrated good clinical improvement. CONCLUSION: Paratesticular rhabdomyosarcoma is a rare aggressive tumor manifesting in children and very young adults. Localized forms have a good prognosis whereas metastatic tumors show very poor results. A well-defined treatment based on surgery and chemotherapy yields good results

Mechanosynthezized Zn3V2O8 Mixed Oxide as Efficient Catalyst of Xylose Conversion to Glycolic Acid in Water

International audienceDifferent catalytic materials of mixed oxide of zinc and vanadium Zn3V2O8 were synthesized using co-precipitation, combustion, alginate gelation and mechanosynthesis methods. The synthesized mixed oxide Zn3V2O8 were characterized by several techniques including XRD, SEM, EDX, XPS and BET. Structural measurement revealed the influence of the synthesis method on the physical and catalytic proprieties of Zn3V2O8 materials. Catalytic performance of Zn3V2O8 has been studied by oxidation of xylose to organic acids in water at 150 degrees C for 1 h. Significantly, this is the first time that the Zn3V2O8 nano-oxide was used as catalyst for xylose oxidation in water. Zn3V2O8 can efficiently catalyze the synthesis of glycolic acid (70% selectivity and 60% yield) from xylose with excellent stability and reusability. The ability to regenerate the Zn3V2O8 was also assessed by determining the change in the reaction indices in successive reaction-regeneration cycles

Microwave-assisted selective oxidation of sugars to carboxylic acids derivatives in water over zinc-vanadium mixed oxide

Zinc-vanadium (Zn3V2O8) nanostructured mixed oxide (ZVO) was synthesized by precipitation method. The ZVO was characterized by TGA, XRD, N2-adsorption/desorption, NH3-TPD, XPS, SEM, and TEM. XPS and NH3-TPD analyses revealed that it was a Zn/V-based strong oxidant catalyst, with a mixture of both Lewis acid and Brønsted surface acid sites. The ZVO was found to be an efficient catalyst for selective oxidation of glucose and xylose to galacturonic and glycolic acid, respectively, under microwave activation. Response surface methodology was applied to find the optimal operating conditions for maximization of the sugar conversion and selectivity. There was a 60% selectivity of galacturonic acid and 46% of glycolic acid using glucose and xylose, respectively. The ability to regenerate the ZVO was assessed by determining the change in the reaction indices in successive reaction–regeneration cycles. The causes of performance activation were ascertained, characterizing the regenerated ZVO by XRD, SEM, and NH3-TPD

Effective Catalytic Delignification and Fractionation of Lignocellulosic Biomass in Water over Zn3V2O8 Mixed Oxide

International audienceThe conversion of poplar wood biomass to highly value-added chemicals and molecular building blocks was achieved by using the dispersed mixed oxide Zn3V2O8 (ZVO) in water under 100 kPa of 10% O-2/N-2 at 160, 180, and 200 degrees C for 4 h. This nanostructured mixed oxide was prepared via the precipitation process and then characterized by several techniques. The results showed that this mixed oxide has interesting catalytic properties and is a versatile catalyst for biomass delignification and lignin and hemicellulose depolymerization. ZVO exhibited high activity on poplar biomass delignification and fractionation (degree delignification > 97%) and lignin and holocellulose conversion with high yield into aromatic and furan compounds (80 mg/g initial wood at 200 degrees C), with high selectivities for 5-hydroxymethylfurfural (HMF) (25 mg/g of initial wood), vanillin, and syringaldehyde

Synthesis of CoFeO mixed oxides via an alginate gelation process as efficient heterogeneous catalysts for lignin depolymerization in water

A catalytic oxidative fragmentation of a lignin dimer and polymer extracted from wheat straw was successfully performed under eco-friendly conditions: 10% O2/N2 as the oxidizing agent, water as the solvent (pH ≈ 7), and Co3O4, Fe2O3 and CoFeO mixed oxides as heterogeneous catalysts and at temperatures of T = 150 °C and 200 °C. These catalysts unexpectedly showed tunable selectivity that directly depends on the composition of the selected bimetallic nanoparticles. High selectivity for benzoic acid and alkylbenzene (above 50%) was observed over Co50–Fe50 at 200 °C. Under similar conditions, the conversion of wheat organosolv lignin over Co50–Fe50 at 150 °C for 4 h yielded up to 50 wt% of monomeric species (based on dry lignin) and up to 19% of aromatic molecules with high selectivity to aromatic aldehydes (syringaldehyde and vanillin), up to 60%. An important fraction of water-soluble oligomers, with low molecular weights, was also formed during the catalytic treatment. The oxide nanomaterials were readily separated from the residual lignin during the recyclability test. The yield and the product distribution can be tuned by choosing the oxidation parameters: temperature, reaction time, oxygen partial pressure, solvent and catalyst charges

Sulfated Well-Defined Mesoporous Nanostructured Zirconia for Levulinic Acid Esterification

International audienceWell-organized zirconia (ZrO 2) nanoparticles forming mesoporous materials have been successfully synthesized via a facile micelle-templating method using cetyltrimethylammonium bromide as a structure-directing template to control the nucleation/growth process and porosity. The systematic use of such a surfactant in combination with a microwave-assisted solvothermal (cyclohexane/water) reaction enabled the control of pore size in a narrow-size distribution range (3−17 nm). The effect of solvent mixture ratio on the porosity of the synthesized oxide was determined, and the controlled growth of zirconia nanoparticles was confirmed by means of powder X-ray diffraction, small-angle X-ray scattering, transmission electron microscopy, selected area electron diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy as well as N 2 physisorption isotherm analysis. Then, the as-prepared nanostructured zirconia oxides were treated with sulfuric acid to have sulfated samples. The catalytic performances of these mesoporous zirconia nanoparticles and their sulfated samples were tested for levulinic acid (LA) esterification by ethanol, with quantitative conversions of LA to ethyl levulinate after 8 h of reaction

Workshop Marrakech

Premier titre de la collection « Architecture de paysage » rassemblant, sur une base annuelle, des recueils issus chacun des enseignements internationaux (Workshop_Atelier/terrain) menés par la Chaire UNESCO en paysage et environnement (CUPEUM) en collaboration avec les programme MOST (Management of Social Transformations), MAB (Man and Biosphere) et WHC (World Heritage Center) de l’UNESCO. Cette collection est dirigée par Philippe Poullaouec-Gonidec, fondateur et titulaire de la seule chaire UNESCO œuvrant dans le domaine du paysage dans le monde. Cet ouvrage diffuse les résultats du Workshop_Atelier/terrain réalisé à Marrakech (Maroc) en novembre 2004. Vitrine privilégiée d’un « Observatoire international des paysages périphériques : villes et métropoles » initié par la CUPEUM, ces recueils constitueront des points singuliers de réflexion sur la question de l’aménagement de la périphérie des villes et des métropoles de la région méditerranéenne