The title compound, [Co2Na2{μ2-N(SiMe3)2}4](μ4-O), (I), represents a new entry in the class of inverse crown ethers. In the mol-ecule, each Co atom is formally in the oxidation state +II. The structure contains one half of a unique mol-ecule per asymmetric unit with the central μ4-oxido ligand residing on an inversion center, leading to a planar coordination to the Na and Co atoms. In the cryst...

Let (S,≤) be a strictly totally ordered monoid, R be a commutative ring and M be an R-module. We show the following results: (1) If (S,≤) satisfies the condition that 0 ≤ s for all s ∈ S, then the module [[MS,≤]] of generalized power series is a semi Hopfian [[RS,≤]]-module if and only if M is a semi Hopfian R-module; (2) If (S,≤) is artinian, then the generalized inverse polynomial module [MS,...

In this study, thermodynamic properties, namely retention volume, infinitely dilute weight fraction activity coefficient, Flory–Huggins interaction parameter, solubility parameter of the polymer, partition coefficient and diffusion coefficients of the various solvents in poly(methyl methacrylate co butyl methacrylate) (PMMA co BMA) at infinite dilution of the solvent have been determined by inv...

In this study, magnetic iron oxide nanoparticles (Fe3O4) with the size range of 20-30 nm were prepared by the modified controlled chemical co-precipitation method from the solution of ferrous/ferric mixed salt-solution in alkaline medium. In this process polyethylene glycol was used as a surfactant to prevent the solution from agglomeration. The prepared magnetic nanoparticles were characterize...

In this study, SiO2 nanoparticles were successfully synthesized via sol-gel precipitation method and the effects of different parameters such as temperature, ethanol, ammonia and tetraethylorthosilicate (TEOS) contents based on water were investigated in a systematic way applying Taguchi experimental design method. It was found that, among all the investigated parameters, ethanol as a co-solven...

Abstract Accurate estimates of the carbon dioxide (CO 2 ) fluxes at earth’s surface are imperative for comprehending cycle mechanisms and providing reliable global warming predictions. Furthermore, they can also provide valuable science-based information that will be helpful in reducing human-induced CO emissions. Inverse analysis is a prominent method quantitatively estimating spatiotemporal v...

The magnetic flux density change ΔB caused by the inverse magnetostrictive effect is key for achieving high-performance vibration power generation. As magnetization curve of polycrystalline Fe–47.6 at. % Co–2.3 V (Fe–Co–V) alloy became easier to magnetize applying tensile stresses, value estimated from curves depended significantly on fields. Hence, generation a U-shaped unimorph device using F...

The complexation reactions between methylthymol blue (MTB) and Co2+, Ni2+, Cu2+, Zn2+ and Pb2+ ions have been studied in different water-methanol mixtures at pH 4.45 and 25 °C by a spectrophotometric technique. The stepwise stability constants of the resulting 1:1 and 2:1 (metal ion to ligand) complexes were determined from the absorban...

The performance of geostatistical and spatial interpolation techniques for estimation of spatial variability of heavy metals and water quality mapping of groundwater resources in Ramiyan district (Golestan province- Iran) were investigated. 24 spring/well water samples were collected and the concentration of heavy metals (Ni, Co, Pb, Cd and Cu) was determined using Differential Pulse Polarograp...