Magnetization studies of chemically prepared manganese dioxides

A study is made of the magnetization properties of commercial, chemically prepared, manganese dioxides which are intended for use in dry cells, zinc alkaline cells and magnesium cells. The technique employs a vibrating sample magnetometer and the properties are measured as a function of applied fields at room temperature. A correlation is found between the shift of the (411) XRD peak and the magnetization behaviour. The results indicate that the magnetizability that is observed in these mostly α-phase containing samples can be accounted for by the average Mn-Mn distance and the consequent interactions between manganese spins mediated by O2- and OH-. Of particular interest to magnetic moments of MnO2 samples with traces of δ phases is the prediction that the extent of the modification of the birnessite phase has a significant influenc

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Studying the STA effects on aluminium alloy joints by friction welding

This article examines the properties of joints fabricated by friction welding (FW) using AA6061-T6 and AA7075 as examples of both similar and dissimilar metals. It also looks at how heat treatment after welding affects the metallurgical characteristics of the joint. The heat treatment method under investigation combines solutionizing heat treatment with synthetic ageing (STA). The tensile characteristics, microhardness, and microstructure of the as-welded and STA-treated welded specimens are assessed in the paper using mechanical testing equipment and metallurgical characterization methods. The findings demonstrate that the joint characteristics are enhanced by precipitate nucleation occurring in the joint interface of the FW similar and dissimilar joint under STA treatment. On the other hand, the STA influence on the tensile strength (TS) of joints made with AA7075 was greater than that of similar joints made with AA6061-T6, as well as dissimilar joints made with both AA6061-T6 and AA7075. Additionally, after STA treatment, the similar joints showed a uniform distribution of hardness. However, in the dissimilar joint after STA treatment, the hardness dropped suddenly on the AA6061-T6 side, specifically from the partially deformed zone (PDZ) towards the heat affected zone (HAZ).</p

Hybrid K-Medoids with Energy-Efficient Sunflower Optimization Algorithm for Wireless Sensor Networks

Wireless sensor network (WSN) sensor nodes should have adequate energy. Reduced energy usage is essential to maximize the endurance of WSNs. Combining WSN with a more significant energy source, a cluster head (CH), is another effective strategy for extending WSN durability. A CH is dependent on the communication inside and between clusters. A CH’s energy level extends the cluster’s life for the complete WSN. Determining the energy required in WSNs while developing clustering algorithms is challenging. For maintaining energy efficiency in WSNs, this research offers K-medoids with sunflower-based clustering and a cross-layer-based optimal routing approach. An efficient fitness function generated from diverse objectives is used to choose the CH. After CH selection, sunflower optimization (SFO) indicates the best data transmission line to the sink node. The proposed protocol, SFO-CORP, increased the network lifetime by 19.6%, 13.63%, 11.13%, and 4.163% compared to the LEACH, EECRP, FEEC-IIR, and CL-IoT protocols, respectively. The experimental results showed that it performed better for packet delivery ratio, energy consumption, end-to-end delay, network lifetime, and computation efficiency

Defects, conductivity and photoconductivity in Ar+ bombarded KTaO 3

Oxygen vacancies play a crucial role in the conductivity of oxides. Here, we report the photoresponse of the electron doped surface of Ar + bombarded oxygen vacant (001) KTaO 3 (KTO) single crystal. The bombardment time defines the amount of oxygen vacancies and hence the electron doping level. The time evolution of photoresponse to daylight illumination remains independent of the carrier density and follows the biexponential function. By contrast, the amplitude of the photoresponse increases with the decreasing charge carrier density. The samples show distinct responses in terms of amplitude as well as response time to the illumination with laser light of wavelengths 633, 532, and 405nm. The defect states distribution within the bandgap is calculated with the photoconductivity relaxation, which involves deep sensitizing hole traps. The combined results of electrical conductivity, photoconductivity, atomic force microscopy, and Kelvin probe force microscopy suggest that the conductivity produced on the KTO surface is not continuous throughout the surface. Rather, Ar + bombardment creates oxygen deficiency patches that are oriented along some preferential crystal orientations and interconnected with each other, thus producing percolating conducting channels on the surface of the sample. Under light illumination, photocarriers are generated in these conducting channels