Polypropylene Composites Reinforced by Marine Posidonia Fiber Waste: Effect of Silane and Alkali treatment

This paper investigates the effects of chemical treatment and the reinforcement rate on the mechanical properties of polypropylene composites reinforced with Posidonia waste fibers. Increasing the reinforcement rate from 20% to 30% improved Young’s modulus and the flexural modulus of the composite. Silane treatment had a positive effect on all the mechanical properties of the composite; on the other hand, the alkali treatment improved the tensile strength but decreased the flexural property of the composite. The greatest Young’s and flexural moduli were obtained in the case of 30% reinforcement treated with silane. The increases in these properties were 57.95% and 44.84% for the tensile and flexural moduli, respectively, compared to pure polypropylene. The mechanical properties of the composite obtained were higher than those of hemp and jute produced under the same conditions using the single-screw extrusion process. The results show that Posidonia waste fiber is an effective candidate to be utilized to produce composites for the automotive industry, such as rear shelves, boot linings, spare wheel compartments, and interior doors, and that it has economic and ecologic advantages in comparison with hemp and jute fibers

Estimates of electronic interaction parameters for LaMMO3_3 compounds (MM=Ti-Ni) from ab-initio approaches

We have analyzed the ab-initio local density approximation band structure calculations for the family of perovskite oxides, La$M$O$_3$ with $M$=Ti-Ni within a parametrized nearest neighbor tight-binding model and extracted various interaction strengths. We study the systematics in these interaction parameters across the transition metal series and discuss the relevance of these in a many-body description of these oxides. The results obtained here compare well with estimates of these parameters obtained via analysis of electron spectroscopic results in conjunction with the Anderson impurity model. The dependence of the hopping interaction strength, t, is found to be approximately $r^{-3}$.Comment: 18 pages; 1 tex file+9 postscript files (appeared in Phys Rev B Oct 15,1996

Development of a Multifunctional Wet Laid Nonwoven from Marine Waste Posidonia oceanica Technical Fiber and CMC Binder

A Posidonia oceanica waste marine plant was used to produce a wet-laid nonwoven web for multifunction applications. To study the effect of some parameters related to the web characteristics (sheet weight, binder ratio, and pulp ratio) on the mechanical and physical properties of the web, we used a Box–Behnken design plan with three levels. The diagram of the superposed contours graphic method was used to find the optimum parameters of the process for the application of the Posidonia nonwoven fiber on an insulation field. With the measurement of the thermal conductivity properties using the box method, the results demonstrated that the nonwoven fiber from Posidonia oceanica marine waste had good insulation properties in comparison with other classical natural fibers (hemp, flax) used in the field of insulation with the big advantage of being a natural product

Electrocaloric effect and energy storage in lead free Gd0.02Na0.5Bi0.48TiO3 ceramic

International audienceThe electrocaloric effect (EC) was investigated in the ferroelectric lead-free Gd0.02Na0.5Bi0.48TiO3 (GdNBT) ceramics. A pure perovskite structure was observed by the X-ray diffraction in GdNBT ceramics synthesized by a solid-state reaction method. Dielectric measurements revealed the existence of different ferroelectric and antiferroelectric transformations in this material. Based on the temperature dependence of P-E loops, reversible electrocaloric temperature changes of about Delta T = 0.75 K at the electric field of 90 kV/cm and the EC responsivity Delta T/Delta E approximate to 0.08 x 10(-6) K m V-1 were obtained in the GdNBT ceramics. The energy-storage density W = 0.85 J cm(-3) and the associated efficiency (eta = 65%) at 413 K were determined from the P-E loops data. The simultaneous existence of EC responsivity and energy-storage density makes GdNBT very promising lead-free material and opens a great potential for its application in electronic devices. (C) 2017 Elsevier Masson SAS. All rights reserved

Development of a Multifunctional Wet Laid Nonwoven from Marine Waste <i>Posidonia oceanica</i> Technical Fiber and CMC Binder

A Posidonia oceanica waste marine plant was used to produce a wet-laid nonwoven web for multifunction applications. To study the effect of some parameters related to the web characteristics (sheet weight, binder ratio, and pulp ratio) on the mechanical and physical properties of the web, we used a Box–Behnken design plan with three levels. The diagram of the superposed contours graphic method was used to find the optimum parameters of the process for the application of the Posidonia nonwoven fiber on an insulation field. With the measurement of the thermal conductivity properties using the box method, the results demonstrated that the nonwoven fiber from Posidonia oceanica marine waste had good insulation properties in comparison with other classical natural fibers (hemp, flax) used in the field of insulation with the big advantage of being a natural product

Electrostatic energy storage in antiferroelectric like perovskite

International audienceLead-free ferroelectric Na0.5Bi0.5TiO3 (NBT) and NBT-doped Ln (Ln = Er and Ho) in both bulk and thin films forms were processed via solid-state reaction and solution deposition respectively. SEM investigations showed dense samples with fine-grained and smooth microstructure for thin films. A pure perovskite structure was observed by the X-ray diffraction for all specimens. The frequency dependences of the dielectric constant and loss tangent were investigated at room temperature and revealed a decrease in the dielectric losses with the introduction of the lanthanide element. The energy storage density (Wrec) was calculated using the obtained P–E loops. The stored and delivered energies were found depending on the form and composition of the sample