Microwave characterization of polymer composite based on Biochar: A comparison of composite behaviour for Biochar and MWCNTs

In this work, Biochar is used as a filler in Epoxy resin for composite preparation. The electrical characteristics of composites are analyzed in function of different filler percentages. Results obtained are compared with composites based on multi-wall carbon nanotubes

Ceramide-induced BOK promotes mitochondrial fission in preeclampsia

Mitochondria are in a constant balance of fusing and dividing in response to cellular cues. Fusion creates healthy mitochondria, whereas fission results in removal of non-functional organelles. Changes in mitochondrial dynamics typify several human diseases. However, the contribution of mitochondrial dynamics to preeclampsia, a hypertensive disorder of pregnancy characterized by placental cell autophagy and death, remains unknown. Herein, we show that the mitochondrial dynamic balance in preeclamptic placentae is tilted toward fission (increased DRP1 expression/activation and decreased OPA1 expression). Increased phosphorylation of DRP1 (p-DRP1) in mitochondrial isolates from preeclamptic placentae and transmission electron microscopy corroborated augmented mitochondrial fragmentation in cytotrophoblast cells of PE placentae. Increased fission was accompanied by build-up of ceramides (CERs) in mitochondria from preeclamptic placentae relative to controls. Treatment of human choriocarcinoma JEG3 cells and primary isolated cytrophoblast cells with CER 16:0 enhanced mitochondrial fission. Loss- and gain-of-function experiments showed that Bcl-2 member BOK, whose expression is increased by CER, positively regulated p-DRP1/DRP1 and MFN2 expression, and localized mitochondrial fission events to the ER/MAM compartments. We also identified that the BH3 and transmembrane domains of BOK were vital for BOK regulation of fission. Moreover, we found that full-length PTEN-induced putative kinase 1 (PINK1) and Parkin, were elevated in mitochondria from PE placentae, implicating mitophagy as the process that degrades excess mitochondria fragments produced from CER/BOK-induced fission in preeclampsia. In summary, our study uncovered a novel CER/BOK-induced regulation of mitochondrial fission and its functional consequence for heightened trophoblast cell autophagy in preeclampsia

Mechanical properties of epoxy/multi-walled carbon nanotubes composites

In this paper, two types of multi-wall carbon nanotubes (MWCNTs) were dispersed into two different epoxy resins b high - shear mixing. Dispersion and homogenisation of nanofillers was analysed by Field Emission Scanning Electron Microscopy (FESEM). Microhardness of epoxy/MWCNTs nanocomposites, as well as of neat epoxy resins, is measure by Vickers method. The evolution of nanocomposites microhardness values were studied in function of curing time takin in account the influence of two different epoxy matrix and MWCNTs. Asymptotic values were analysed and compare with those of pure epoxy resin

Repurposing Face Masks after Use: From Wastes to Anode Materials for Na-Ion Batteries

Nowadays, face masks play an essential role in limiting coronavirus diffusion. However, their disposable nature represents a relevant environmental issue. In this work, we propose the utilization of two types of disposed (waste) face masks to prepare hard carbons (biochar) by pyrolytic conversion in mild conditions. Moreover, we evaluated the application of the produced hard carbons as anode materials in Na-ion batteries. Pristine face masks were firstly analyzed through infrared spectroscopy and thermogravimetric analysis. The pyrolysis of both mask types resulted in highly disordered carbons, as revealed by field-emission scanning electron microscopy and Raman spectroscopy, with a very low specific surface area. Anodes prepared with these carbons were tested in laboratory-scale Na-metal cells through electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic cycling, displaying an acceptable specific capacity along a wide range of current regimes, with a good coulombic efficiency (>98% over at least 750 cycles). As a proof of concept, the anodes were also used to assemble a Na-ion cell in combination with a Na3V2(PO4)(2)F-3 (NVPF) cathode and tested towards galvanostatic cycling, with an initial capacity of almost 120 mAhg(-1) (decreasing at about 47 mAhg(-1) after 50 cycles). Even though further optimization is required for a real application, the achieved electrochemical performances represent a preliminary confirmation of the possibility of repurposing disposable face masks into higher-value materials for Na-ion batteries

Convective Heat Transfer Enhancement for Electronic Device Applications using Patterned MWCNTs Structures

This article reports on the heat transfer characteristics of columnar Vertically Aligned Multiwall Carbon Nanotubes (VA-MWCNTs) grown on a patterned Si surface. In the first part, we describe the procedure for patterning the silicon (Si) surface and the growth of MWCNTS on these patterned surfaces. The diameter of MWCNTs grown by Chemical Vapor Deposition (CVD) technique was in the range of 30-80 nm. In the second part structures mimicking macroscopic finned heat sinks are used for enhancing forced convective heat transfer on a silicon substrate. Convective heat transfer coefficient has been experimentally measured for silicon substrates with and without MWCNT-based fins on it. The configuration with MWCNTs based fins shows an enhancement in convective heat transfer of 40% and 20%, as maximum and average value respectively, compared to the bare silicon. Experiments have been carried out in a wind tunnel with air as coolant in fully turbulent regime. These encouraging results and the possibility of growing structures directly on silicon can be regarded as a first step

Sistema E.V.A. 1.0

Dentro del campo del crecimiento y desarrollo, el cálculo antropométrico, es una de las herramientas más utilizadas para encontrar indicadores válidos del estado general del crecimiento biológico de una población en su interacción con los diversos factores sociales. Frente al evidente proceso de pauperización por el que viene transcurriendo el país, la evaluación del estado nutricional de la población infantil, tanto en sus aspectos poblacionales como individuales, se hace necesaria y cotidiana. Presentamos aquí un software de escritorio que permite el cálculo y la graficación de las principales variables antropométricas. El E.V.A. 1.0 (Evaluación y Visualización Antropométrica) brinda también la posibilidad de almacenar los datos, de incorporar tablas de comparación (por default el sistema trae las tablas de la SAP y del NCHS), y de exportar la información al programa EPINFO y a la mayoría de las aplicaciones estándar de escritorio (planillas de cálculo, procesadores de texto, etc.). La aplicación posee también una modalidad de sugerencias de diagnóstico, con referencias bibliográficas, que puede ser de ayuda, tanto para el profesional de A.P.S. como para el investigador.Asociación de Antropología Biológica de la República Argentin

Sistema E.V.A. 1.0

Dentro del campo del crecimiento y desarrollo, el cálculo antropométrico, es una de las herramientas más utilizadas para encontrar indicadores válidos del estado general del crecimiento biológico de una población en su interacción con los diversos factores sociales. Frente al evidente proceso de pauperización por el que viene transcurriendo el país, la evaluación del estado nutricional de la población infantil, tanto en sus aspectos poblacionales como individuales, se hace necesaria y cotidiana. Presentamos aquí un software de escritorio que permite el cálculo y la graficación de las principales variables antropométricas. El E.V.A. 1.0 (Evaluación y Visualización Antropométrica) brinda también la posibilidad de almacenar los datos, de incorporar tablas de comparación (por default el sistema trae las tablas de la SAP y del NCHS), y de exportar la información al programa EPINFO y a la mayoría de las aplicaciones estándar de escritorio (planillas de cálculo, procesadores de texto, etc.). La aplicación posee también una modalidad de sugerencias de diagnóstico, con referencias bibliográficas, que puede ser de ayuda, tanto para el profesional de A.P.S. como para el investigador.Asociación de Antropología Biológica de la República Argentin

Effect of the ingestion in the WRF model of different Sentinel-derived and GNSS-derived products: analysis of the forecasts of a high impact weather event

This paper presents the first experimental results of a study on the ingestion in the Weather Research and Forecasting (WRF) model, of Sentinel satellites and Global Navigation Satellite Systems (GNSS) derived products. The experiments concern a flash-floodevent occurred in Tuscany (Central Italy) in September 2017. The rationale is that numerical weather prediction (NWP) models are presently able to produce forecasts with a km scale  spatial resolution, but the poor knowledge of the initial state of the atmosphere may imply an inaccurate simulation of the weather phenomena. Hence, to fully exploit the advances in numerical weather modelling, it is necessary to feed them with high spatiotemporal resolution information over the surface boundary and the atmospheric column. In this context, the Copernicus Sentinel satellites represent an important source of data, because they can provide a set of high-resolution observations of physical variables (e.g. soil moisture, land/sea surface temperature, wind speed) used in NWP models runs. The possible availability of a spatially dense network of GNSS stations is also exploited to assimilate water vapour content. Results show that the assimilation of Sentinel-1 derived wind field and GNSS-derivedwater vapour data produce the most positive effects on the performance of the forecast

Biochar as a cheap and environmental friendly filler able to improve polymer mechanical properties

This study reports about the use of Biochar derived from maple tree as a filler in Epoxy resin. Maple tree blocks were pyrolyzed in inert atmosphere at 600 °C and 1000 °C respectively and were characterized morphologically. The composite mechanical properties, i.e. stress-strain curves and related parameters (ultimate tensile strength, Young modulus, resilience, tensile toughness) were recorded as well as their friction coefficient. It is shown that at very low wt.% of the filler, the Young modulus is increased while at higher wt.% (2 wt% and above) the fragile behavior of the resin was converted in a ductile one, as elongation at break increased from 0.02 to 0.12. A huge impact of the filler is observed on tensile toughness as for the best sample is increased 11 times with respect with pure resin. A simple model able to describe the results and make predictions on other wt.% is presented as well

study of carbon nanotubes based polydimethylsiloxane composite films

Thanks to their remarkable characteristics, carbon nanotubes (CNTs) have fields of applications which are growing every day. Among them, the use of CNTs as filler for polymers is one of the most promising. In this work we report on Polydimethylsiloxane (PDMS) composites with different weight percentages (0.0% to 3.0%) of multiwall carbon nanotubes (MWCNTs) having diameter 10?30 nm and length 20?30 ?m. To achieve optimum dispersion of CNTs in PDMS matrix, high speed mechanical stirring and ultrasonication were performed. By using the doctor blade technique, 70 ?m thick uniform films were produced on glass. They were subsequently thermally cured and detached from the glass to get flexible and self standing films. The surface morphological study done by FESEM, shows that CNTs are well dispersed in the PDMS. Raman spectroscopy and FTIR were used to investigate the possible structural changes in the polymer composite. To examine the optical behavior UV-VIS spectroscopy was employed in both specular and diffused modes. A linear increase in absorption coefficient is found with the increasing percentage of CNTs while the transmittance decreases exponentially. The results confirm the dependence of optical limiting effect on the quantity of MWCNTs. Based on optical study, MWCNTs/PDMS composite films can be a promising material to extend performances of optical limiters against laser pulses, which is often required in lasing systems