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Due to the absence of the rotor windings, the brushless doubly fed reluctance generator (BDFRG) presented a much better efficiency with less complicated control and modelling than that introduced by the brushless doubly fed induction generator. As a result, the BDFRG gained more preference than that of the doubly fed induction generator. Moreover, this result led to the emerging of the (BDFRG) as one of the most promising generators in the new modern wind turbines. This paper introduces modelling as well as control strategy for the grid-connected BDFRG-based wind turbine systems. This study was carried out using MATLAB/Simulink environment.

Three-dimensional graphene (3DG) sponge has attracted increasing attention because it combines the unique properties of cellular materials and the excellent performance of graphene. Preparation of 3DG sponge depends mainly on the self-assembly of graphene oxide sheets. In the case of using uniform large graphene oxide and ultralarge graphene oxide sheets, the nematic liquid crystals (LCs) phases are formed at low concentration. After chemical reduction, the LCs of GO solution are converted to 3DG sponges with a high degree of orientation, offering a new methodology to regulate the controlled large GO sheets. The orientation of GO solution can be inherited by 3DG sponge, making the sponge to have a large-scale ordered network structure. The 3D elastic graphene sponges have low density and good elasticity, promising for the applications in strain sensing, shock damping, and energy cushioning. Our work explores a novel strategy for organizing the ordered alignment of controlled large GO sheets and exploring the relationship between the microstructures and mechanical properties of 3DG sponge.

We have synthesized fusiform gold nanoparticles by recovering gold from a solution of gold nanoparticles obtained by dispersing of gold electrodes in hexane by pulsed plasm in liquid method. Formation of fusiform gold nanoparticles with length from 50 to 150 nm, and diameter of 5–15 nm was achieved by pulsed plasma in liquid method. Fusiform gold nanoparticles obtained by our method are different from the spindle-shaped gold nanoparticles which were synthesized from the growth solution, due to their loose structure, while spindle-shaped gold nanoparticles are dense and much larger in size (length 300–400 nm, diameter ~ 100–150 nm). In addition to this work, dumbbell-shaped magnetite/gold (Fe3O4/Au) nanoparticles were synthesized by using magnetite nanoparticles obtained in a cetylpyridinium bromide (CpyBr) solution with concentration of 0.1% and a gold nanosolution, where 0.1% sodium citrate solution was applied as a reducing agent. Our proposed method is characterized by the forming of discharge localization during the electrodes erosion process, simpler and does not require use of nuclei in the form of spherical gold nanoparticles and presence of growth solution. Fusiform gold nanoparticles were formed by simple reduction with sodium citrate from gold nano-solution.

In this research, the physical, chemical and biological properties of 19 soil indicators using 80 samples (0–25 cm) were quantified to measure the soil quality index (SQI) in Miandoab region, Iran, across different land uses. These properties include aggregate stability (AS), bulk density (BD), soil moisture content (θm), saturation percentage (SP), particle size fractions (clay, silt, sand), pH, EC, available P and K, OC, total N, C/N, CaCO3, sequestration of organic carbon (SOC), CEC, microbial respiration (MR) and microbial population (MP). Principal component analysis (PCA) was used as a dimension reduction method to separate farmlands and orchards as two different land uses. The linear SQI and nonlinear SQI were calculated, and the results showed a clear difference in SQI as affected by the aforementioned land uses. The specific contribution of each minimum data set also showed that soil OC, N, MR, MP, silt, CaCO3, AS and BD had the highest importance to SQI. The linear SQI value was more significantly affected by the physical properties than the chemical and biological ones. It varies from the maximum value of 35.17% in the farmland to 37.74% in the orchard. On the other hand, the nonlinear SQI showed the highest contribution of biological SQI in the farmland (73.94%) followed by the orchard (64.15%). Finally, both linear and nonlinear equations may be acceptable for assessing SQI using the aforementioned soil properties. Furthermore, it is the biological properties that have the main role in terms of evaluating the effect of land use conversion on soil quality.

Flexible manipulators are widely used in overhead cranes for industrial purposes and accurate control of the tip point of such a system is very difficult. Control of a 6DOF flexible manipulator is attempted in this study. Model of the manipulator is built in sim-mechanics environment of MATLAB and simulated. Joints of the manipulator are made flexible with the use of joint spring and damper. The behavior of the system was found to be unstable and a controller was used to bring the stability. For this purpose, a conventional PID controller was used and its gain values are tuned using different approaches in this study. Finally, a manually designed fuzzy logic-based approach was also used to tune the PID gains and compared with that of the conventional tuning approaches. In order to apply controller to the system, equivalent linearized transfer function of the model is derived in MATLAB. Among all the conventional tuned PID controllers applied, RRT-based method has performed best in terms of phase margin and gain margin. Also, the performance of fuzzy logic-tuned PID controller was found to be better compared to the conventional PID tuned controllers.

Diffusion bonding was accomplished between Ti–6Al–4V alloy and AISI 304 austenitic stainless steel utilizing copper as an interlayer in the holding time variety of 45–105 min for 925 °C under 14 MPa load in a vacuum. After bonding, the microstructural study including metallographic examination and energy dispersive spectroscopy, microhardness survey, lap shear strength test, and ram tensile test were accomplished. From the results, holding time is a major influence to develop the microstructural characteristics and improve the joints quality. The occasion of various intermetallic compounds, for example, CuTi, Cu3Ti2, FeTi, Fe2Ti, Cr2Ti has been expected from the ternary phase diagrams of Fe–Cu–Ti and Fe–Cr–Ti. These reaction items were insisted on the X-ray diffraction method. The highest bond strength of 268 MPa was attained for the pair bonded at 90 min holding time. This is a direct result of the better combination of the mating surface. With the expansion in holding time to 105 min, the quality was reduced caused by the expanded volume fraction of discontinuities.

This study utilized the FTIR technique to investigate and assess the herbicide 2, 4-Dichlorophenoxyacetic acid-induced blood serum toxicity. The study was conducted on 15 albino Wistar rats, divided into two groups: a control group (5 rats) and an intoxicated group (10 rats). Serum samples were investigated using the FTIR technique, and the obtained spectra from both groups were analyzed. Our results indicated a reduction in glucose, lipid, and protein content and remarkable changes in the secondary structure of protein in response to herbicide toxicity. A rise in the DNA content was also noticed. Our findings prove the FTIR technique's capability to detect biochemical changes in biological samples due to toxicity.

The present work aimed to carry out the machining of EN-42 spring steel in wire electrical discharge machining with zinc-coated brass wire using distilled water as a dielectric medium. The effect of WS2 powder added in a dielectric medium, on the metal removal rate and surface roughness has been evaluated. With the use of WS2, the conductivity of the dielectric is found to be constantly equal to 10 S/m, which is a very promising feature. WS2 enhances dielectric life, metal removal rate, and surface roughness significantly. The effect of cryogenically treated wire on the metal removal rate and surface roughness during machining has been carried out. Taguchi method and genetic algorithm were used to optimize machining performance measures. Both methods provide optimum parameters and target value. The results of the Taguchi method show more error as compared to the genetic algorithm. The on time can be predicted as the most significant parameter according to the Taguchi method. From the results, it is observed that higher on time shows better metal removal rate and lower on time shows a better surface finish.

The incidence of heavy metal contamination in Zamfara State, northern Nigeria, due to artisanal mining in some villages has resulted in the pollution of a vast area of land and water. This study evaluated the extent of environmental risks caused by heavy metals. It involved five (5) villages (Bagega, Dareta, Sunke, Tunga, and Abare) where mining activities were taking place and Anka town with no record of mining activities served as control. In each of the five villages, three sites (3) were identified as a mining site, processing site, and village making a total of sixteen (16) sites. Bulked soil samples were collected in triplicate and analyzed for iron, lead, cadmium, chromium, zinc, and nickel using flame atomic absorption spectrophotometry. Measured concentrations of the heavy metals in soils were then used to calculate the pollution and ecological risk pose by heavy metals. Their concentrations were in the order Fe > Pb > Cr > Zn > Cd > Ni, with Pb and Cd having a concentration higher than permissible levels for soils and accounted for 98.64% of the total potential ecological risk. Also, all the different pollution indices examined showed that all the sites were polluted with Cd, and all the processing sites were polluted with Pb. This reveals that processing sites pose more risk to heavy metal contamination. Correlation analysis showed a highly significant (p < 0.001) positive correlation between Pb and Zn, Cr and Ni, and a significant (p < 0.01) positive correlation between Fe and Pb, Zn and Cr. The principal component analysis suggested that Pb, Zn, Cr, and Ni likely originated from the same source, i.e., mining activities, and Fe and Cd originated from the abundant parent material in the study area.