Soil salinization is a gradual degradation process that begins as a minor problem and grows to become a significant economic loss if no control action is taken. It progressively alters the soil environment which eventually negatively affects plants and organism that were not originally adapted for saline conditions. Soil salinization arises from diverse sources such as side-effects of long-term use of agro-chemicals, saline parent rocks, periodic inundation of soil with saline water, etc. In Africa, soil salinization has not been adequately documented particularly in the croplands. The objective of this study was to identify trends of cropland salinization in Africa and how its relationship with long-term land use practices affected the soil environment. The study analysed soil salinization between 1965 and 2020 using measured electrical conductivity (EC), spatial modelling with environmental covariates, and national statistics on cropland expansion and application of mineral fertilizers, herbicides, and pesticides. The results showed increasing trends of EC in Africa due to climatic and land use drivers. Increasing trends of EC, which evidenced salinization, was found in 31 million hectares of topsoils and 18 million hectares of subsoils. About 2 million hectares of croplands were depicted with salinization and >25 million hectares at the risk of salinization in the arid and semi-arid areas. The study also found statistical relationships between semi-arid cropland salinization and trends of agro-chemical use and cropland sizes. There were significant (p < 0.001) positive correlations between semi-arid cropland salinization and trends of cropland expansion and applied nitrogenous fertilizers. It found that increasing trend of applied mineral nitrogenous fertilizers could double the odds of salinization in semi-arid croplands while cropland expansion could increase the odds of semi-arid cropland salinization by >10 %. These findings present ground-breaking baseline information for future works on sustainable land-use practices that can control cropland soil salinization in Africa.

Electron transport in complex fluids, biology, and soft matter is a valuable characteristic in processes ranging from redox reactions to electrochemical energy storage. These processes often employ conductor-insulator composites in which electron transport properties are fundamentally linked to the microstructure and dynamics of the conductive phase. While microstructure and dynamics are well recognized as key determinants of the electrical properties, a unified description of their effect has yet to be determined, especially under flowing conditions. In this work, the conductivity and shear viscosity are measured for conductive colloidal suspensions to build a unified description by exploiting both recent quantification of the effect of flow-induced dynamics on electron transport and well-established relationships between electrical properties, microstructure, and flow. These model suspensions consist of conductive carbon black (CB) particles dispersed in fluids of varying viscosities and dielectric constants. In a stable, well-characterized shear rate regime where all suspensions undergo self-similar agglomerate breakup, competing relationships between conductivity and shear rate were observed. To account for the role of variable agglomerate size, equivalent microstructural states were identified using a dimensionless fluid Mason number, [Formula: see text], which allowed for isolation of the role of dynamics on the flow-induced electron transport rate. At equivalent microstructural states, shear-enhanced particle-particle collisions are found to dominate the electron transport rate. This work rationalizes seemingly contradictory experimental observations in literature concerning the shear-dependent electrical properties of CB suspensions and can be extended to other flowing composite systems.

Ion implantation of laser induced graphite plasma has been performed for modifications in surface, optical, electrical and structural properties of CR-39. KrF Excimer laser (248 nm, 18 ns, 120 mJ), at an irradiance of 2.5 × 108 W cm-2 is utilized for the production of graphite plasma. The energy and fluence of graphite ions are estimated by Thomson parabola technique. The targets are implanted with energy of 710 KeV graphite ions for four fluences ranging from 26 × 1012 to 92 × 1015 ions/cm2, in presence of magnetic field of strength 90 mT. The digital optical analysis reveals well-arranged dendritic and island like structure formation on irradiated polymer surface. Confocal microscopic investigation illustrates the growth of nano/micro sized craters and hillocks for various ion fluences. Dissociation of bonds along with formation of new bonds is confirmed from Raman analysis. UV-Vis spectral analysis reveals that the optical transmittance values for visible regions of CR-39 are drastically reduced from 90 % to 68 % for maximum laser fluence of 92 × 1015 ions.cm-2. Significant improvement in electrical conductivity is achieved from 10-9 to 10-7 Scm-1 for lowest fluence value of graphite ions. SRIM software is utilized for the measurement of stopping power or Linear Energy Transfer (LTE) of 710 Kev graphite ions, is about, 55.53 eV/Ǻ, in the CR-39 targets.

The COVID-19 pandemic highlighted the need to create and study new substances with improved lipophilicity and antimicrobial properties, such as ionic liquids (ILs), with easily tunable physicochemical properties. Most ILs possess strong antibacterial effects, but ILs containing the imidazolium cation are even more effective than the positive control. Thus, in this study, three ionic liquids with 1-butyl-3-methylimidazolium cation and various carboxylate anions (phenylacetate, benzoate, and 4-methoxyphenylacetate) were synthesized and fully characterized. The interactions between the cations and anions were discussed based on the experimental density, viscosity, and electrical conductivity. From the measured electrical conductivity and viscosity, the Walden plot is constructed and ionicity of the studied ILs is discussed. The similarities and dissimilarities among the studied ILs and their physicochemical properties are analyzed by applying the hierarchical cluster analysis and in silico calculated properties. The antimicrobial activity of the studied ionic liquids is tested on two bacterial (E. coli and P. aeruginosa) and three fungi (P. verrucosum, A. flavus, and A. parasiticus) strains, finding that they showed improved antimicrobial activity compared to the individual components.

The remarkable stability, suitable thermomechanical characteristics, and acceptable electrical properties of donor-doped strontium titanates make them attractive materials for fuel electrodes, interconnects, and supports of solid oxide fuel and electrolysis cells (SOFC/SOEC). The present study addresses the impact of processing and thermochemical treatment conditions on the electrical conductivity of SrTiO3-derived ceramics with moderate acceptor-type substitution in a strontium sublattice. A-site-deficient Sr0.85La0.10TiO3-δ and cation-stoichiometric Sr0.85Pr0.15TiO3+δ ceramics with varying microstructures and levels of reduction have been prepared and characterized by XRD, SEM, TGA, and electrical conductivity measurements under reducing conditions. The analysis of the collected data suggested that the reduction process of dense donor-doped SrTiO3 ceramics is limited by sluggish oxygen diffusion in the crystal lattice even at temperatures as high as 1300 °C. A higher degree of reduction and higher electrical conductivity can be obtained for porous structures under similar thermochemical treatment conditions. Metallic-like conductivity in dense reduced Sr0.85La0.10TiO3-δ corresponds to the state quenched from the processing temperature and is proportional to the concentration of Ti3+ in the lattice. Due to poor oxygen diffusivity in the bulk, dense Sr0.85La0.10TiO3-δ ceramics remain redox inactive and maintain a high level of conductivity under reducing conditions at temperatures below 1000 °C. While the behavior and properties of dense reduced Sr0.85Pr0.15TiO3+δ ceramics with a large grain size (10-40 µm) were found to be similar, decreasing grain size down to 1-3 µm results in an increasing role of resistive grain boundaries which, regardless of the degree of reduction, determine the semiconducting behavior and lower total electrical conductivity of fine-grained Sr0.85Pr0.15TiO3+δ ceramics. Oxidized porous Sr0.85Pr0.15TiO3+δ ceramics exhibit faster kinetics of reduction compared to the Sr0.85La0.10TiO3-δ counterpart at temperatures below 1000 °C, whereas equilibration kinetics of porous Sr0.85La0.10TiO3-δ structures can be facilitated by reductive pre-treatments at elevated temperatures.

The necessity for high operational temperatures presents a considerable obstacle to the commercial viability of solid oxide fuel cells (SOFCs). The introduction of active co-dopant ions to polycrystalline solid structures can directly impact the physiochemical and electrical properties of the resulting composites including crystallite size, lattice parameters, ionic and electronic conductivity, sinterability, and mechanical strength. This study proposes cobalt-iron-substituted gadolinium-doped ceria (CoxFe1-xGDC) as an innovative, nickel-free anode composite for developing ceramic fuel cells. A new co-precipitation technique using ammonium tartrate as the precipitant in a multi-cationic solution with Co2+, Gd3+, Fe3+, and Ce3+ ions was utilized. The physicochemical and morphological characteristics of the synthesized samples were systematically analysed using a comprehensive set of techniques, including DSC/TGA for a thermal analysis, XRD for a crystallographic analysis, SEM/EDX for a morphological and elemental analysis, FT-IR for a chemical bonding analysis, and Raman spectroscopy for a vibrational analysis. The morphological analysis, SEM, showed the formation of nanoparticles (≤15 nm), which corresponded well with the crystal size determined by the XRD analysis, which was within the range of ≤10 nm. The fabrication of single SOFC bilayers occurred within an electrolyte-supported structure, with the use of the GDC as the electrolyte layer and the CoO-Fe2O3/GDC composite as the anode. SEM imaging and the EIS analysis were utilized to examine the fabricated symmetrical cells.

La0.6Sr0.4CoO3 (LSC) coatings with a thickness of 50-100 µm were deposited on Fe-25Cr ferritic stainless steel (DIN 50049) via screen printing. The required suspension had been prepared using fine LSC powders synthesised using EDTA gel processes. In its bulk form, the LSC consisted entirely of the rhombohedral phase with space group R-3c, and it exhibited high electrical conductivity (~144 S·cm-1). LSC-coated steel was oxidised in air at 1073 K, i.e., under conditions corresponding to SOFC cathode operation, for times of up to 144 h. The in situ electrical resistance of the steel/La0.6Sr0.4CoO3 layered system during oxidation was measured. The products formed on the samples after the oxidation reaction resulting from exposure to the corrosive medium were investigated using XRD, SEM-EDS, and TEM-SAD. The microstructural, nanostructural, phase, and chemical analysis of films was performed with a focus on the film/substrate interface. It was determined that the LSC coating interacts with the oxidised steel in the applied conditions, and a multi-layer interfacial zone is formed. Detailed TEM-SAD observations indicated the formation of a main layer consisting of SrCrO4, which was the reaction product of (La,Sr)CoO3, and the Cr2O3 scale formed on the metal surface. The formation of the SrCrO4 phase resulted in improved electrical conductivity of the investigated metal/ceramics layered composite material, as demonstrated by the low area-specific resistance values of 5 mΩ·cm2, thus making it potentially useful as a SOFC interconnect material operating at the tested temperature. In addition, the evaporation rate of chromium measured for the uncoated steel and the steel/La0.6Sr0.4CoO3 layered system likewise indicates that the coating is capable of acting as an effective barrier against the formation of volatile compounds of chromium.

Amorphous ZrO2 thin films with increasing Mg content were deposited on quartz substrates, by dip coating method. The films are transparent in the visible domain and absorbent in UV, with an optical band gap that decreases with the increase of Mg content, from 5.42 eV to 4.12 eV. The temperature dependent conductivity measurements showed typical semiconductor comportment. The decrease of the electrical conductivity by Mg doping was related to the increase of the OH groups (37% to 63%) as seen from X-ray Photoelectron Spectroscopy. It was found out that the electrical conductivity obeys the Meyer-Neldel rule. This rule, previously reported for different disordered material systems is obtained for ZrO2 for the first time in the literature. Exploring novel aspects of Mg-doped ZrO2, the present study underscores the origin of the Meyer-Neldel rule explained by the small-polaron hopping model in the non-adiabatic hopping regime. Determination of the presence of such a conduction mechanism in the samples hold promise for comprehending the important aspects, which might be a concern in developing various devices based on Mg-doped ZrO2.

The combination of hydrogel and fertilizer as slow release fertilizer hydrogel (SRFH) has become one of the most promising materials to overcome the shortcomings of conventional fertilizer by decreasing fertilizer loss rate, supplying nutrients sustainably, and lowering the frequency of irrigation. The hydrogel based on carboxymethyl cellulose (CMC) and polyacrylic acid (PAA) (CMC/PAA) was synthesized. All materials, Vinasse, hydrogel (CMC/PAA) and (Vinasse/CMC-PAA) were characterized by FTIR, XRD, and SEM. The formed hydrogel was applied to control the salinity of Vinasse to use it as a cheap and economical fertilizer. The results showed that using the prepared hydrogel with Vinasse (V/CMC-PAA) as a slow-release organic fertilizer decreased the EC value through the first six hours from 1.77 to 0.35 mmohs/cm. Also, using V/CMC-PAA can control and keep the potassium as fertilizer for 50 days. The productivity per feddan from the sugar cane crop increased by about 15%, and the number of irrigations decreased from 5 to 4 times.

This study undertook a comprehensive examination of the double perovskite complex Ba2FeWO6, investigating its structural, electrical, magnetic, thermal and elastic characteristics. The study used density functional theory (DFT), specifically the full potential linearized augmented plane wave (FP-LAPW) method. It also used different approximations, including the generalized gradient approximation (GGA) and the modified Trans-Blaha (TB-mBJ) approach, to improve the accuracy of the band gap estimation more accurate. Additionlly, the GGA + U approach, incorporating the Hubbard correction term (U), was utilized. Our findings indicate that Ba2FeWO6 exhibits indirect half-metallic band gaps in the (L-X) direction, with value of 0.91 eV and a net magnetic moment of 4 μB, predominatly influenced by the iron atom. The compound demonstrated exceptional characteristics suitable for thermoelectric applications, particularly at lower temperatures. Furthermore, the elasticity analysis revealed low brittleness, facilitates its manipulation in manufacturing procedures.