Hydrothermal Synthesis of Ferroelectric Mixed Potassium Niobate–Lead Titanate Nanoparticles

Potassium niobate–lead titanate solid‐solution nanoparticles have been synthesized using a new hydrothermal method. The key step is an in situ acid–base exothermic reaction with a large excess of KOH, generating an amorphous precipitated gel. This gel, when crystallized in an autoclave for 2 h at 190°C, produces a mixed perovskite solid solution with [KNbO₃]_0.8–[PbTiO₃]_0.2 (KNPT) composition, and parallelepiped particles rang in size from a few tens to a few hundreds of nanometer in length. This study proves that the pure perovskite phase can be obtained in spite of the different solubilities of the reactive cations in an ethanol–water solution. Dielectric measurements show that KNPT ceramic with a grain size of 50 nm is ferroelectric at room temperature. In addition, ceramics sintered at 950°C have an average grain size of 500 nm, and exhibit a maximum permittivity of 2100 at 1 kHz near T_C = 510 K and a remanent polarization P_r = 12 μC/cm²     

Ozonation And AOP Parameter Estimation From Countercurrent Film Absorber Data

Degradation of phenolic compounds in Kohtla-Järve oil shale ash dump wastewater (North-East Estonia) by O₃, O₃/UV, O₃/H₂O₂, O₃/H₂O₂/UV, O₃/TiO₂ and O₃/TiO₂/UV treatment in a countercurrent film absorber was studied experimentally. The mathematical model and the simulation algorithm of the processes were developed. The random search optimizer was applied to evaluate the values of reaction rate constant, mass transfer enhancement factor, stoichiometric coefficient and volatilization coefficient for organics into the process models. The evaluated coefficients for individual phenolic compounds, total content of phenolic compounds and COD for different oxidation systems are presented and discussed. “Operation” of the simulated film absorber (based on the evaluated coefficients) and the experimental column are compared.     

Olive oil authentication,traceability and adulteration detection using DNA‐based approaches

Olive oil is the fresh juice produced by pressing olive fruits. It serves as the main component of the Mediterranean diet and one of the most valuable products of the agro‐food industry, not only for its taste, but also for its high nutritional value. As it is considered the lipid constituent of the olive fruits, it is composed mainly of triglycerides and phenolics. Authentication and traceability of extra virgin olive oil is a challenging research task due to the complexity of fraudulent practices. Various chemical and biochemical techniques have been developed for determining the authenticity of olive oil. Olive oil DNA‐based analyses have gained attention in recent years, due to high specificity, sensitivity and reliability. DNA analyses have very high discriminating power because ultimately the unique identity of a variety or species is to a great extent genetically dependent. Polymorphisms are genetic variations which refer to the variation in populations or species. Molecular markers provide information on genetic variations and are valuable tools to determine olive oil authenticity. Molecular markers such as SNPs, microsatellites, SCARs and AFLPs have been used for the identification of the varietal origin of olive oils. This feature provides an overview of the current trends and critical issues on DNA‐targeted approaches used for traceability and authenticity of olive oil.     

Electrochemical performance of quaternary (1-x)ZnMn2O4/(x)MgFe2O4 solid solution as supercapacitor electrode

Novel nano quaternary metals solid solutions from MgFe₂O₄ and ZnMn₂O₄ were synthesized using a sol-gel procedure. The development of a solid solution and the formed phase were examined by phase analysis utilizing the X'Pert High Score Plus program and Fourier transform infrared (FTIR) spectroscopy technique. Rietveld analysis of X-ray diffraction data (XRD), scanning electron microscope (SEM/EDS) and transmission electron microscope (TEM) were applied to determine the lattice parameters, crystallite size, different cations distribution and elemental analysis of the formed solid solutions. The measured dielectric properties of obtained solid solutions are found to be affected by the composition ratio (x). The solid solution (1-x)ZnMn₂O₄/(x)MgFe₂O₄ samples exhibited a ferroelectric–paraelectric transition at ferroelectric Curie temperature (T_c). The different hopping mechanisms in the different samples were also examined. The electrochemical performance was tested and influence of composition ratio (x) on the cathodic and anodic potential was investigated. The specific capacitance (C_s) value of electrodes depended on the composition ratio (x) beside the type of cations forming oxides. The (0.9)MgFe₂O₄/(0.1)ZnMn₂O₄ sample showed the best performance as a supercapacitor material. The outstanding electrochemical property of the (0.9)MgFe₂O₄/(0.1)ZnMn₂O₄ electrode was further confirmed by EIS inspection. The super stability of MgFe₂O₄/ZnMn₂O₄ solid solution could be attributed to the activation of the solid solution materials during the CV cycling and the synergistic effects.     

Synthesis of manganese oxide/carbon nanotube nanocomposites using wet chemical method

Novel material with peculiar properties can be obtained by introducing foreign materials into the inner cavity of carbon nanotubes. It has been suggested that the materials encapsulated into the hollow regions of carbon nanotubes could result in a significant change of the properties of these small particles, forming new hybrid composites with extraordinary properties. In this short communication, filling of carbon nanotubes with manganese oxide by wet chemical method is demonstrated. Transmission electron microscopy (TEM) result showed the hollow structure of carbon nanotubes were filled with manganese oxide. Energy dispersive X-rays (EDX) spectra elucidate the presence of manganese oxide in the filled carbon nanotubes whereas SEM result showed that manganese oxide is not crystallized at the outer surface of carbon nanotubes.     

Effect of vanadium and tungsten doping on the structural,optical, and electronic characteristics of TiO2 nanoparticles

Journal of Materials Science: Materials in Electronics - Nanoparticles of TiO2 and Ti0.97M0.03O2 (M≡V, W) samples were produced using sol–gel procedure. Utilizing synchrotron x-ray...     

Controlling the optical characteristics of CdSx thin film by changing the stoichiometric ratio (x)

Journal of Materials Science: Materials in Electronics - CdSx thin films (x?=?1.0, 0.8, 0.6, 0.4, 0.2) were prepared by the sol–gel spin coating method. The grazing incidence...     

Environmental meso-economics in university curriculum: new master program in environmental technology and management

A new Master Program in environmental technology and management has been developed in the framework of the Swiss-Jordanian cooperation, to ensure sustainable knowledge transfer in environmental management, technology, and economics. The areas represented in this program are cleaner production, hazardous substances management, and meso-economic analysis. All of these areas are under the theme of integrated resources management. The program implementation is carried out at Princess Sumaya University for Technology PSUT through cooperation with universities and environmental organizations in Switzerland, which was started in February 2008. The need for establishing this program in Jordan emerged from the practical experience of the Swiss partners who are working in environmental management. It was found that the concept of integrated resources management and the efficient utilization of resources were under estimated by practitioners. This leads to the urge of establishing a comprehensive program to upgrade the capacity of practitioners and new graduates to be able to handle environmental resources in a sustainable manner. For this purpose, the program includes and promotes the use of a number of tools. Meso-economic analysis is introduced in the program as a suitable tool to reflect the environmental values in monetary perspective, and to fill the gap at a meso (sector level) between the traditional micro (enterprise level) and macro (country level). Thus, meso-analysis comes out with integrated picture about the whole country’s sector and its related environmental damage and remediation options.