Wearable Electrospun Piezoelectric Mats Based on a PVDF Nanofiber-ZnO@ZnS Core-Shell Nanoparticles Composite for Power Generation.

This work adopted a strategy to use new functional high-performance piezoelectric materials for sustainable energy production in wearable self-powered electrical devices. An innovative modification in electrospinning was used to produce highly aligned nanofibers. In the nanogenerator, the flexible membrane constituents were tunefully combined. The novel composite nanofibers were made of Poly (vinylidene fluoride) PVDF, loaded with ZnO@ZnS core-shell nanoparticles to achieve a non-brittle performance of the hetero nanoparticles and piezoelectric polymer. A nanofiber mat was inserted between two thermoplastic sheets with conductive electrodes for application in wearable electronic devices. Complete spectroscopic analyses were performed to characterize the nanofiber's material composition. It is shown that the addition of 10 wt % ZnO@ZnS core-shell nanoparticles significantly improved the piezoelectric properties of the nanofibers and simultaneously kept them flexible due to the exceedingly resilient nature of the composite. The superior performance of the piezoelectric parameter of the nanofibrous mats was due to the crystallinity (polar ß phase) and surface topography of the mat. The conversion sensitivity of the PVDF device recorded almost 0.091 V/N·mm3, while that of the PVDF-10 wt % ZnO@ZnS composite mat recorded a sensitivity of 0.153 V/N·mm3, which is higher than many flexible nano-generators. These nanogenerators provide a simple, efficient, and cost-effective solution to microelectronic wearable devices.

Spectroscopic study of the coloring techniques used in Egyptian ceramics from the ptolemaic and roman period.

The manufacture of the Egyptian Faience through the periods of Ptolemaic and roman shows intense use of polychrome; our main concerns in this research are investigating the parameters controlling the blue color variation and the production of the apple green Faience. Archaeological faience samples belonging to the Ptolemaic and Roman periods representing various color hues were extensively studied using multiple spectroscopic techniques to explore the color palette of the Egyptian artist in this period and highlight the most significant features of their ways of coloring and fabrications. X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) results revealed quartz-rich body feature for all samples, with defined boundaries in some samples due to coloring techniques. The investigated Faience are not lead-alkaline glazes but possibly soda (plant ash) or mixed-alkali glazes with inter-particle glass phases. The high lead content accompanied by antimonite and percentage of sulphur suggested the usage of natron salt flux. The apple green glazes are a yellow lead antimonite mixed with copper oxides. The color varies from deep apple green to light apple green based on the content of oxides in the sample.

Safe and economic disposal of water treatment residuals by reusing it as a substitution layer in roads construction (spectroscopic and geotechnical study).

Cost-effective construction techniques, such as reusing waste materials, play important role in dramatically reduce costs. In recent years, sludges have gained considerable attention as a geotechnical material. Increase in the demand of drinking water from purification plants produces a huge amount of water treatment residuals (WTRs). The disposal of such residues can be considered problematic issue. In this study, innovate and economic method to disposal of WTRs was presented. Comprehensive experimental investigations have been done to determine the effect of utilizing WTRs as a substitution layer in collapsing soil through roads construction processes. The investigations extended to the geotechnical and spectroscopic properties. Tests were carried out on the soil sample mixing with 0, 4, 8, 12, and 16% of WTRs. The samples morphology and composition are characterized by scanning electron microscopy (SEM) and the energy dispersive spectroscope analyzer (EDS). The microstructure and organic constituents are analyzed by X-ray diffraction (XRD) and the Fourier transform infrared (FTIR). The geotechnical measurements include particle size distribution (PSD), single odometer test (SOT), modified proctor test, and the California bearing ratio (CBR). The microstructure analysis confirms that WTRs acted as a pore filler to decrease in porosity and create a denser and solidified structure which reduces the suction and maximum collapse potential. Mineralogical analyses implied that the soil with WTRs turns into a rich medium with metal cations and organic matters that react with minerals to form binding materials. From the geotechnical point of view, WTRs can be safely deposed by mixing with collapsing soil as a subgrade of road construction up to a value of 10% without any impact or reduction on CBR values. The reduction in the required amount of subgrade required by 10% effectively decreases the cost of road construction. Moreover, the results illustrate the remarkable improvement in the collapse potential of the soil, which is reduced by about 24.7% by mixing it with 10% WTRs.

Spectroscopic studies on the phosphorus adsorption in salt-affected soils with or without nano-biochar additions.

Biochar amendment may be an effective solution of maintaining phosphorus (P) and sustaining agricultural production in salt affected soils. However, the behavior of P adsorption in salt-affected soils with nano-biochar (nB) amendment is unclear. Batch adsorption experiments were conducted to investigate the impacts of different levels of soil salinity amended with nB at rates of 0, 0.10%, 0.20%, and 0.50% (w/w) on the P adsorption isotherm and also, mechanisms of P adsorption by using spectroscopic analysis. The results showed that P adsorption increased with increasing soil salinity with or without nB addition. Under level of 120 mg P L-1, adsorption capacity of P increased from 992.8 mg kg-1 for high saline soil (S5) to 1144.0 mg kg-1 after treated with 0.20% nB. The results of P adsorption were agreed with Langmuir and Freundlich isotherm models. Fourier transform infrared analysis (FTIR) of nB showed that the surface of nB decorated with oxygenated functional groups which play an important role in the adsorption of P anions. Analyzes of FTIR and XRD indicated that the main adsorption mechanism for P adsorption on nB in salt affected soils was surface precipitation. Our findings suggest that the nano-biochar amendment in salt affected soils can be a promising enhancer for P adsorption.

Characterization of Carnobacterium maltaromaticum LMA 28 for its positive technological role in soft cheese making.

Carnobacterium maltaromaticum is a lactic acid bacterium isolated from soft cheese. The objective of this work was to study its potential positive impact when used in cheese technology. Phenotypic and genotypic characterization of six strains of C. maltaromaticum showed that they belong to different phylogenetic groups. Although these strains lacked the ability to coagulate milk quickly, they were acidotolerant. They did not affect the coagulation capacity of starter lactic acid bacteria, Lactococcus lactis and Streptococcus thermophilus, used in dairy industry. The impact of C. maltaromaticum LMA 28 on bacterial flora of cheese revealed a significant decrease of Psychrobacter sp. concentration, which might be responsible for cheese aging phenomena. An experimental plan was carried out to unravel the mechanism of inhibition of Psychrobacter sp. and Listeria monocytogenes and possible interaction between various factors (cell concentration, NaCl, pH and incubation time). Cellular concentration of C. maltaromaticum LMA 28 was found to be the main factor involved in the inhibition of Psychrobacter sp. and L. monocytogenes.