The Electrospun Ceramic Hollow Nanofibers

Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity, and their sensitivity. In particular, semiconductor ceramic hollow nanofibers show greater space charge modulation depth, higher electronic transport properties, and shorter ion or electron diffusion length (e.g., for an enhanced charging–discharging rate). In this review, we discuss and introduce the latest developments of ceramic hollow nanofiber materials in terms of synthesis approaches. Particularly, electrospinning derivatives will be highlighted. The electrospun ceramic hollow nanofibers will be reviewed with respect to their most widely studied components, i.e., metal oxides. These nanostructures have been mainly suggested for energy and environmental remediation. Despite the various advantages of such one dimensional (1D) nanostructures, their fabrication strategies need to be improved to increase their practical use. The domain of nanofabrication is still advancing, and its predictable shortcomings and bottlenecks must be identified and addressed. Inconsistency of the hollow nanostructure with regard to their composition and dimensions could be one of such challenges. Moreover, their poor scalability hinders their wide applicability for commercialization and industrial use

Simplified Method for Single Line to Ground-Fault Location in Electrical Power Distribution Systems

Power distribution systems play important roles in modern society. When distribution system outages occur, speedy and precise fault location is crucial in accelerating system restoration, reducing outage time and significantly improving system reliability, and then improves the quality of services and customer satisfaction. In this paper, we propose a reduced algorithm utilizing the sum of sending-end currents of the three phases to calculate the fault current, and therefore, avoid the iterative aspect of the classic algorithm for single line to ground fault location and reduce its computational charge. The test results are obtained from the numerical simulation using the data of a distribution line recognized in the literature

Effect of the structural features of biobased linear polyester plasticizers on the crystallization of polylactides

This work presents, for the first time, a detailed report on how the nucleation and crystallization of polylactide (PLLA) are affected by biobased aliphatic polyesters plasticizers. Three biobased polyesters were synthesized via solvent-free two-stage melt polycondensation of adipic acid (AdA) with three different biobased aliphatic diols and used as plasticizers for poly (L-lactic acid) (PLLA). The molecular structure of the synthesized polyesters was proved using H-1 NMR, C-13 NMR and Fourier transform infrared (FTIR) spectroscopy. PLLA/AdA-based blends containing 10 wt% of the polyester plasticizers were studied by tensile tests, dynamic mechanical analysis (DMA), wide-angle x-ray scattering (WAXS), differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM). Adding the plasticizers to PLLA decreased T-g by up to 11 degrees C and significantly increased the elongation at break by about 8 times compared with neat PLLA. The addition of 10 wt% of any AdA-based plasticizer to PLLA increases the nucleation rate from the glassy state by around 50-110 % depending on the plasticizer. The overall crystallization rate from the glassy state was 2-3 times faster for the plasticized PLLAs than neat PLLA. These results are a consequence of the lower energy barrier for both nucleation and growth processes. The incorporation of AdA-based linear polyesters had an incremental impact on the crystal growth rate (or secondary nucleation) of PLLA spherulites from the melt and glassy states. In conclusion, the AdA-based aliphatic polyesters allowed to enhance PLLA crystallization rates and showed interesting potential for the formulation of fully biobased PLLA blends.The authors are grateful to the Luxembourg National Research Fond (FNR) for financial support (CATBIOSE project INTER/ANR 15/9903334) . We would like to acknowledge Coraline Sirot, Regis Vaude-mont and Benot Marcolini who continuously provide a friendly and supportive environment to help us conduct our work. We acknowledge the financial support from the BIODEST project; this project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 778092. This work has also received funding from the Basque Government through grant IT1309-19

Apport de l'IRM dans la maladie de Creutzfeldt-Jakob: à propos d'un cas

La maladie de Creutzfeld-Jacob (MCJ) est une affection très rare et fatale qui atteint le système nerveux central. Elle est caractérisée par une détérioration mentale aboutissant à une démence progressive, une symptomatologie pyramidale et extra-pyramidale ainsi que des myolclonies. Un diagnostic précoce est essentiel pour prévenir la transmission interhumaine. Nous rapportons le cas d'un patient âgé de 62 ans chez qui le diagnostic de MCJ sporadique a été retenu, en se basant sur le tableau clinique fait de syndrome démentiel avec myoclonies précédées de troubles du comportement, des hallucinations et de dépression, et sur les données de l'IRM encéphalique qui a montré des hyper signaux au niveau du striatum et au niveau cortical en séquences pondérées Flair et diffusion

UV-stable paper coated with APTES-modified P25 TiO2 nanoparticles

In order to inhibit the photocatalytic degradation of organic material supports induced by small titania (TiO2) nanoparticles, highly photocatalytically active, commercially available P25-TiO2 nanoparticles were first modified with a thin layer of (3-aminopropyl) triethoxysilane (APTES), which were then deposited and fixed onto the surface of paper samples via a simple, dip-coating process in water at room temperature. The resultant APTES-modified P25 TiO2 nanoparticle-coated paper samples exhibit much greater stability to UV-illumination than uncoated blank reference paper. Very little, or no, photo-degradation in terms of brightness and whiteness, respectively, of the P25-TiO2-nanoparticle-treated paper is observed. There are many other potential applications for this Green Chemistry approach to protect cellulosic fibres from UV-bleaching in sunlight and to protect their whiteness and maintain their brightness

Contribution à l'étude morphologique, ultrastructurale et chimique de la figue de barbarie. Les polysaccharides pariétaux: charactérisation et modification chimique

In a general context of food and non food valorization of the prickly pear, we were interested in the morphological analysis of the peel and the seeds of the fruit. The cell wall polysaccharides of the different tissues were isolated, purified, and their characterization was achieved by chemical methods as well as high resolution 1H and 13C NMR and CP/MAS. The other aspects of the work describe the chemical modification of the cellulose microfibrills. First of all, the oxidization of cellulose samples by the TEMPO-NaOCl-NaBr system were studied and the different parameters conditions were optimized in order to prepare polyglucuronic acid samples. Secondly, we studied the coupling, via peptide linkages, with poly(N-isopropylacrylamide) in order to synthesize thermosensitive biopolymers starting from oxidized cellulose samplesDans un contexte général de valorisation alimentaire et non alimentaire du figuier de barbarie, nous nous sommes intéressés lors de cette étude à l'analyse morphologique de la pelure et des graines du fruit. Les polysaccharides pariétaux des différentes parois ont été isolés, purifiés, et leurs caractérisations ont été réalisées grâce aux méthodes chimiques ainsi qu'à la RMN haute résolution (1H et 13C) et en phase solide (CP/MAS). L'autre aspect du travail décrit la modification chimique des microfibrilles de cellulose. Il traite, dans un premier temps, de l'oxydation de la cellulose par le système TEMPO-NaOCl-NaBr et les conditions opératoires ont été optimisées dans le but de préparer des échantillons d'acide polyglucuroniques. La seconde étape met l'accent sur le greffage, via un couplage peptidique, du poly-N-isopropylacrylamide en vue d'élaborer des biopolymères thermostimulables à partir de la cellulose oxydée