Viscosities and densities of ternary systems of CaCl 2 − NaCl−water were measured in the range of T = (293.15 to 323.15) K at 5 K intervals and up to 4.5 mol•kg −1 . Two equations based on the Exponential and Goldsack and Franchetto models were applied to correlate the experimental viscosity data as a function of concentration and temperature. The optimized parameters showed that the presence of CaCl 2 had a prevailing effect on the viscosity of the ternary solutions than NaCl. The dependency of the viscosity optimized parameters on temperature was investigated, too. The average absolute deviation between calculated and experimental viscosities was below 1.4 %. The work compared the above-mentioned two models to the known extended Jones− Dole equation and found that both models do correlate the viscosity at higher concentrations better than the Jones−Dole equation. However, the exponential model shows the superior representation for the experimental viscosity values over the other two studied models. Density data were successfully predicted with an average absolute deviation of less than 0.45 %.

In this study, magnetic Zinc Ferrite (ZnFe 2 O 4 )@TiO 2 nanofibers were prepared by low cost and nontoxic route; hydrothermal technique followed by electrospinning process. The prepared magnetic ZnFe 2 O 4 @TiO 2 nanofibers were morphologically and structurally analyzed by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and thermal gravimetric analysis (TGA). The prepared magnetic ZnFe 2 O 4 @TiO 2 nanofibers were utilized as photoanode for the fabrication of dye-sensitized solar cells (DSSCs) and presented applicable performance with 4.2% overall conversion efficiency with high short circuit current density (J SC ) of 10.16 mA/cm 2 . The maximum ∼42% incident photo-to-current conversion efficiency (IPCE) value was also recorded at 520 nm. In addition, ZnFe 2 O 4 @TiO 2 nanofibers were not only possessed the good conversion efficiency, but also shown excellent photocatalytic efficiency with magnetic properties towards the dye remediation. Prepared ZnFe 2 O 4 @TiO 2 nanofibers can be considered as a promising material for energy conversion and environmental applications.

Measured viscosity and density data for ternary aqueous solutions of CaCl2 and KCl are presented at temperatures between 293 and 323 K with 5 K increment. A modified Jones–Dole was introduced by adding extra terms and proved to be suitable for modelling of the viscosity data. Goldsack and Franchetto, Hu and Exponential models are used to correlate the viscosity data, too. Al models are correlated as a function of temperature and concentration. All models had successfully predicted the viscosity with high precision reaching a maximum average absolute deviation (AAD) of less than 2.3%. The modified Jones–Dole showed the best results among other models. Viscosity of the ternary solution is higher than the viscosity of water by about 15% at low concentrations and reaches about 270% at the highest concentrations. The amount of CaCl2 has more significant effect on the ternary mixture viscosity compared to KCl. This has created difficulty in measuring the viscosity and consequently the challenge in finding the different models parameters. Ternary solution densities were successfully correlate with Kumar’s model with AAD of less than 0.4%. Comparison of the ternary solution density and viscosity with the few available data literature showed a good agreement.

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Abstract:The critical properties of La 0.8 Ca 0.2 Mn 1−x Co x O 3 (x = 0, 0.1, 0.2 and 0.3) compounds were investigated by analysis of the magnetic measurements in the vicinity of their critical temperature. Arrott plots revealed that the paramagnetic PM-ferromagnetic (FM) phase transition for the sample with x = 0 is a first order transition, while it is a second order transition for all doped compounds. The critical exponents β, γ and δ were evaluated using modified Arrott plots (MAP) and the Kouvel-Fisher method (KF). The reliability of the evaluated critical exponents was confirmed by the Widom scaling relation and the universal scaling hypothesis. The values of the critical exponents for the doped compounds were consistent with the 3D-Heisenberg model for magnetic interactions. For x = 0.1, the estimated critical components are found inconsistent with any known universality class. In addition, the local exponent n was determined from the magnetic entropy change and found to be sensitive to the magnetic field in the entire studied temperature range.

In this study, the phytotoxic effects caused by the exposure to five different concentrations of two veterinary antibiotics (Tylosin, and Enrofloxacin) that are commonly used for the treatment of farm animals as antibacterial agents were considered. The impact of antibiotic residues was evaluated on the germination percentage, accumulation, and seedling elongation of the barley seeds using Petri dishes under controlled environmental conditions. The treatments were distributed randomly using Completely Randomized Design (CRD). The germination percentage was significantly inhibited with the increasing Enrofloxacin dose concentrations, while, it was to some extent on the contrary in the case of Tylosin, where seed germination was enhanced as a result of increasing Tylosin concentrations. Liquid chromatography-tandem mass spectrometry LC/MS-MS was used to detect and quantify the uptake dosage after drying and extracting the antibiotic compounds from the seedling.

Abstract:A method for the measurement of total mercury (T-Hg) in environmental samples using cold vapour atomic absorption spectrometry (CV AAS) has been validated yielding a dynamic range (0.04-10.00 µg/kg) and high certified reference material (CRM) recovery (>90%). The validation was carried out according to International Union of Pure and Applied Chemistry (IUPAC) validation and Eurachem Guides. A freeze-dried and homogenised sample was weighed and then digested using Suprapur acids (HNO 3 , H 2 SO 4 , and HF) with potassium dichromate solution in a hot block digestion system. A calibration curve was constructed (R 2 > 0.999). Two CRMs (Marine Sediment Reference Material (PACS-3) and Trace Elements in Muscle Tissue (Trace Elements and Methylmercury in Mussel Tissue (NIST2976)) were utilised for quality assurance and control. The limit of quantification (LOQ) calculated as 0.04 µg/kg, and uncertainty (U) calculated as 2%. The obtained results showed the suitability of this method for direct mercury measurement in environmental samples. Additionally, the proficiency of this method was recognised by accreditation under the standard of International Organization for Standardization (ISO/IEC 17025:2017) for competence of testing and calibration laboratories.

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