Synthesis of Cyano-Benzylidene Xanthene Synthons Using a Diprotic Brønsted Acid Catalyst, and Their Application as Efficient Inhibitors of Aluminum Corrosion in Alkaline Solutions.

Novel cyano-benzylidene xanthene derivatives were synthesized using one-pot and condensation reactions. A diprotic Brønsted acid (i.e., oxalic acid) was used as an effective catalyst for the promotion of the synthesis process of the new starting xanthene-aldehyde compound. Different xanthene concentrations (ca. 0.1-2.0 mM) were applied as corrosion inhibitors to control the alkaline uniform corrosion of aluminum. Measurements were conducted in 1.0 M NaOH solution using Tafel extrapolation and linear polarization resistance (LPR) methods. The investigated xanthenes acted as mixed-type inhibitors that primarily affect the anodic process. Their inhibition efficiency values were enhanced with inhibitor concentration, and varied according to their chemical structures. At a concentration of 2.0 mM, the best-performing studied xanthene derivative recorded maximum inhibition efficiency values of 98.9% (calculated via the Tafel extrapolation method) and 98.4% (estimated via the LPR method). Scanning electron microscopy (SEM) was used to examine the morphology of the corroded and inhibited aluminum surfaces, revealing strong inhibitory action of each studied compound. High-resolution X-ray photoelectron spectroscopy (XPS) profiles validated the inhibitor compounds' adsorption on the Al surface. Density functional theory (DFT) and Monte Carlo simulations were applied to investigate the distinction of the anticorrosive behavior among the studied xanthenes toward the Al (111) surface. The non-planarity of xanthenes and the presence of the nitrile group were the key players in the adsorption process. A match between the experimental and theoretical findings was evidenced.

Modification of the Structure and Linear/Nonlinear Optical Characteristics of PVA/Chitosan Blend through CuO Doping for Eco-Friendly Applications.

The solution casting technique is utilized to fabricate blank and CuO-doped polyvinyl alcohol/chitosan (PVA/CS) blends for eco-friendly applications. The structure and surface morphologies of prepared samples were explored by Fourier transform infrared (FT-IR) spectrophotometry and scanning electron microscopy (SEM), respectively. FT-IR analysis reveals the incorporation of CuO particles within the PVA/CS structure. SEM analysis exposes the well-dispersion of CuO particles in the host medium. The linear/nonlinear optical characteristics were found on the basis of UV-visible-NIR measurements. The transmittance of the PVA/CS decreases upon CuO increasing to 20.0 wt%. The optical bandgap (Eg dir./Eg ind.) decreases from 5.38/4.67 eV (blank PVA/CS) to 3.72/3.12 eV (20.0 wt% CuO-PVA/CS). An obvious improvement in the optical constants of the PVA/CS blend is achieved by CuO doping. The Wemple-DiDomenico (WDD) and Sellmeier oscillator models were utilized to examine the CuO role dispersion behavior of the PVA/CS blend. The optical analysis shows clear enrichment of the optical parameters of the PVA/CS host. The novel findings in the current study nominate CuO-doped PVA/CS films for applications in linear/nonlinear optical devices.

Mechanical stress in the urbanized Roman Phoenician coast.

OBJECTIVE: Skeletal populations from Byblos, Beirut, and Tyre were studied to assess mechanical stress along the Roman Phoenician coast. MATERIALS: The sample included 153 adult skeletons. METHODS: Skeletal remains were macroscopically assessed for osteoarthritis, intervertebral disc disease (IDD), and Schmorl's nodes. RESULTS: The Byblos population experienced higher levels of mechanical stress than the Beirut and Tyre ones. Sex-based differences were also found in all skeletal assemblages with males likely engaging in physically more demanding tasks. CONCLUSIONS: The variation in mechanical stress, and associated physically demanding tasks, between these populations can be attributed to their differing political and economic status during the Roman period; textual sources highlight the economic and political dominance of Beirut and Tyre, emanating from their status as coloniae. SIGNIFICANCE: This study represents one of the first attempts to investigate mechanical stress in coastal Phoenicia during the Roman period. It provides valuable insights into the biocultural structure of understudied communities at the periphery of the Roman world, and can serve as a basis for further future research into the occupational patterns of Phoenician communities. LIMITATIONS: The contextual information for these skeletal populations is very limited and does not allow secure conclusions regarding their representativeness. The sample sizes are also rather small, especially when divided per sex and age. SUGGESTIONS FOR FURTHER RESEARCH: Further investigation employing complementary methods such as cross-sectional geometric properties and entheseal changes is needed to reconstruct the occupational patterns of these communities, taking into account cultural, environmental, and temporal factors.

The anthropogenic radiotoxic element of 137Cs accumulate to biota in the Mediterranean Sea.

The abundance of 137Cs radionuclide in the Mediterranean Sea has limited study despite its environmental effects in seafood chains. For this purpose, the activity concentration of 137Cs in sediment and seawater have been determined using a high-resolution HPGe gamma-spectrometry system. The average activity concentrations in sediment and water were 14.16 Bq kg-1 and 1.74 mBq L-1, respectively. The results were used as input data of ERICA Tool modelling software to assess marine organisms' accumulation and dose. The highest and lowest accumulate activity concentration values were observed in birds (9.24E-01 Bq kg-1) and the Vascular plant (1.37E-02 Bq kg1), respectively. The total dose rate value was ranged between 1.94E-06 µGy h-1 (Phytoplankton) to 4.70E-03 µGy h-1 (Polychaete worm). The total dose rates of 137Cs to the selected organisms were all <0.001 µGy h-1, and there is no significant risk to marine biota in the study area.

Exploring the FTIR, Optical and Nuclear Radiation Shielding Properties of Samarium-Borate Glass: A Characterization through Experimental and Simulation Methods.

(Tl2O3)30-(Li2O)10-(B2O3)(60-y)-(Sm2O3)y glass system with various Sm2O3 additives (y = 0, 0.2, 0.4, 0.6) was studied in detail. The vibrational modes of the (Tl2O3)30-(Li2O)10-(B2O3)(60-y) network were active at three composition-related IR spectral peaks that differed from those mixed with Samarium (III) oxide at high wavenumber ranges. These glass samples show that their permeability increased with the Samarium (III) oxide content increase. Additionally, the electronic transition between localized states was observed in the samples. The MAC, HVL, and Zeff values for radiation shielding parameters were calculated in the energy range of 0.015-15 MeV using the FLUKA algorithm. In addition, EBF, EABF, and ΣR values were also determined for the prepared glasses. These values indicated that the parameters for shielding (MAC, HVL, Zeff, EBF, EABF, and ΣR) are dependent upon the Samarium (III) oxide content. Furthermore, the addition of Samarium (III) oxide to the examined glass samples greatly reinforced their shielding capacity against gamma photon. The findings of the current study were compared to analyses of the XCOM software, some concretes, and lead. In the experiment, it was found that the SMG0.6 glass sample was the strongest shield.

A study of the nanostructure and efficiency of solid-state dye-sensitized solar cells based on a conducting polymer.

In this work the nanostructure and efficiency of solid-state dye-sensitized solar cells based on a conducting polymer have been investigated. A conducting polymer has been used as a solid-state electrolyte in the dye-sensitized solar cells. The polymer used in this study is a form of polythiophene synthesized in aqueous media. The obtained polymers were in two different structures: nanoparticles and networks. The structure of the synthesized polymers has been investigated using transmission electron microscope (TEM) and atomic force microscope (AFM). Furthermore, the optical and electrical properties of the synthesized polymers have also been considered. Solid-state dye-sensitized solar cells (SSDSCs) have been successfully constructed using these two polymers in addition to the linear poly(3-hexylthiophene) (P3HT). The photovoltaic characteristics of the assembled solar cells showed a good performance under annealing at 100 °C when using the network structure of polythiophene with a conversion power efficiency of 0.83%, while the nanoparticles polythiophene achieved 0.15% efficiency compared to 5.6 × 10-5% when using P3HT.