A new inorganic framework in the synthesis of barium carbonate nanoparticles via convenient solid state decomposition route

BaCO₃, a common mineral with important applications in industry, has been synthesized in the orthorhombic phase with a high purity. As a new precursor, barium-o-phthalate complex was applied to prepare BaCO₃ nanoparticles via solvent-free thermal decomposition route. Thermogravimetric analysis (TGA) was applied to determine the thermal behavior of the complex. The products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). The best results were obtained for the sample prepared at 500 °C. Transmission electron microscopy (TEM) of this product shows “bean-like” shaped nanoparticles with an average size of 35–70 nm. The purity, composition and stoichiometry of the as-prepared sample were studied by Electron Diffraction X-ray spectroscopy (EDX) spectra.     

Synthesis, Characterization, and Optimization of Co2SnO4 Nanoparticles via Co-precipitation Method

Nano-structured pure Co₂SnO₄ powders have been synthesized using the co-precipitation method in the presence of oleic acid (OA) as a capping agent. The Taguchi L₄ statistical design was used to investigate the effect of the main parameters (i.e., OA concentration, calcination time, and calcination temperature) on Co₂SnO₄ formation, crystallite size, and morphology. Co₂SnO₄ particles were characterized by powder x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy, scanning electron microscopy (SEM), Fourier transform of infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and Brunauer-Emmett-Teller (BET) surface area measurements. The formation of small and well-crystalline particles, on the order of 41.12-90.60 nm in crystal size, has been determined from XRD patterns and confirmed by SEM and DLS. The specific surface area was measured by a BET method to be 25.43 m²/g. The particle size of the product was observed by DLS to be in the range of 40-105 nm. The results indicated that calcination temperature has the most significant effect on the produced cobalt stannate crystal size.     

Seasonal Influence on Vapor-and Particle-Phase Polycyclic Aromatic Hydrocarbon Concentrations in School Communities Located in Southern California

Ambient concentrations of 15 vapor-and particle-phase (PM _2.5 ) polycyclic aromatic hydrocarbons (PAHs), listed by the US EPA as priority pollutants, were measured between July 2002 and November 2003 in six Southern California communities participating in a multi-year chronic respiratory health study of schoolchildren. The communities were geographically distributed over two hundred kilometers, extending from Long Beach in coastal Los Angeles, to high mountain areas to the north and west of the Los Angeles basin, and south into Eastern San Diego County. Seasonal and spatial variation in the atmospheric concentrations of PAHs is of interest because this class of compounds includes potent mutagens, carcinogens, and species capable of generating reactive oxygen species (ROS) that may lead to oxidative stress. Naphthalene accounted for 95% of the total PAH mass; annual averages ranged from 89 to 142 ng m ^{? 3} . Benzo[ghi]perylene (BGP) and the pro-carcinogen benzo[a]pyrene (BAP), present almost exclusively in the particle-phase, ranged respectively from 38 to 231 pg m ^?3 and 75 and 111 pg m ^{? 3} , with the highest values observed in Long Beach, a community with a high volume of seaport-related activities, and Lancaster, a commuter dormitory community. A considerable increase in the particle-phase PAH concentration, relative to the vapor-phase, was observed as ambient temperature decreased. Cold/hot season ratios for PAHs in PM _2.5 averaged 5.7, reaching 54 at Long Beach. The presented data underscore the importance of seasonal variations on atmospheric PAH concentrations. These observations are relevant to future interpretation and analysis of community-scale human health effects research.     

Antimicrobial Ionic Liquid-Based Materials for Biomedical Applications

Excessive and unwarranted administration of antibiotics has invigorated the evolution of multidrug-resistant microbes. There is, therefore, an urgent need for advanced active compounds. Ionic liquids with short-lived ion-pair structures are highly tunable and have diverse applications. Apart from their unique physicochemical features, the newly discovered biological activities of ionic liquids have fascinated biochemists, microbiologists, and medical scientists. In particular, their antimicrobial properties have opened new vistas in overcoming the current challenges associated with combating antibiotic-resistant pathogens. Discussions regarding ionic liquid derivatives in monomeric and polymeric forms with antimicrobial activities are presented here. The antimicrobial mechanism of ionic liquids and parameters that affect their antimicrobial activities, such as chain length, cation/anion type, cation density, and polymerization, are considered. The potential applications of ionic liquids in the biomedical arena, including regenerative medicine, biosensing, and drug/biomolecule delivery, are presented to stimulate the scientific community to further improve the antimicrobial efficacy of ionic liquids.     

Effect of Ni Doping on the Structural and Optical Properties of TiO<Subscript>2</Subscript> Nanoparticles at Various Concentration and Temperature

TiO₂ nanopowders doped by Ni were prepared by sol–gel method. The effects of Ni ion (transition metal ion) doping on the physical structural and optical properties of TiO₂ have been investigated by X-ray diffraction (XRD), scanning electron microscopy and UV–Vis absorption spectroscopy. XRD results suggest that adding impurities has a significant effect on anatase phase stability, crystallinity, and particle size of TiO₂. The phase transformation from anatase to rutile was inhibited by Ni ion doped TiO₂ at temperatures 675 °C. The lowest band gap value (2.83 eV) was obtained for TiO₂-4%Ni sample calcined at 675 °C.     

Conflict resolution using game theory and rough sets

Conflicts occur naturally in the real world at all levels of society, individually, in groups or society as a whole. Almost all the existing conflict resolution models are unilateral in their decision‐making process. They do not consider the actions of the involved parties simultaneously. Therefore, in this paper, we aim to design a novel conflict resolution model based on game‐theoretic rough sets by constructing a game between all the concerned parties (players), computing the payoff of different strategies and classifying them following equilibrium rules. The proposed model yields more realistic and accurate results as it explores all possibilities and is flexible in determining different threshold values relative to the complexities of real‐life problems. Three real‐life conflict situations are solved with the proposed model, and a comprehensive analysis is done to validate the effectiveness of the proposed approach.