The incorporation of magnetic barium hexaferrite nanoparticles in a transparent polymer matrix of poly(methyl methacrylate) (PMMA) is reported for the first time. The barium hexaferrite nanoplatelets doped with Sc3+, i.e., BaSc0.5Fe11.5O12 (BaHF), having diameters in the range 20 to 130 nm and thicknesses of approximately 5 nm, are synthesized hydrothermally and stabilized in 1-butanol with dodecylbenzenesulfonic acid. This method enables the preparation of monolithic nanocomposites by admixing the BaHF suspension into a liquid monomer, followed by in-situ, bulk free-radical polymerization.
COBISS.SI-ID: 18777878
Modifications of Cu and Cu40Zn surfaces were achieved by their immersions in ethanol solutions of stearic acid with and without the additions of Vitamin E. The surface morphologies, wettability, and corrosion resistance were characterised by means of SEM, water contact-angle, potentiodynamic measurements and EIS. The corrosive media was artificially prepared acid rain at 25 °C. Significant increase in the contact angle indicated that the biomimetic morphology effectively repelled water from the metal surface. Electrochemical measurements indicated that Vitamin E additionally improved the inhibitory properties of the as-prepared hydrophobic layer against corrosion. The inhibitive effectiveness increased to more than 99%.
COBISS.SI-ID: 28503847
Conventional treatment of wastewater from the metal finishing industry is generally based on physical-chemical treatment. Although the effluents from this can be discharged directly there is an increasing interest in industrial wastewater reuse. This requires further wastewater treatment. Here we studied the technical and economic feasibilities of adding an ultrafiltration process as a pre-treatment for removing dissolved and colloidal contaminants ) 0.4 nm, and to eliminate membrane fouling before a final reverse osmosis process resulting in permeate that would meet reuse criteria. The results show that the ultrafiltration - reverse osmosis treatment removed between 91.3% and 99.8% of the contaminants from the effluent, such as metal elements, organic, and inorganic compounds. Contaminants such as suspended solids, nickel, ammonium nitrogen, sulphate nitrogen, chemical oxygen demand, and biochemical oxygen demand were completely removed, the concentrations in the permeate being under the detection limits, thus the quality of the ultrafiltration - reverse osmosis process met the reuse criteria. This demonstrates the technological feasibility of wastewater reuse during electro-plating processes and the pre-treatment of powder coating processes. An economic feasibility analysis was performed based on a reuse capacity for 30,000 m3 per year of treated water for two selected production lines at the Gorenje facility at Velenje, Slovenia. Specifically, the current water costs (including the operational costs of wastewater treatment, potable water use for industrial process and pre-treatment, and taxes) were compared with the investment required to implement the ultrafiltration - reverse osmosis processes. Based on the presented scientific results, the analysis shows that there is a potential for implementing this process within the metal finishing industry.
COBISS.SI-ID: 18622998
A series of nickel–copper alloy magnetic nanoparticles with a range of Curie points from 51 °C to 63 °C were prepared by the reduction of intimately mixed nickel and copper oxides in a silica matrix using the sol–gel method. The silica matrix was subsequently removed with an etching solution, assisted by sonication. The alloy nanoparticles were characterized using X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA/SDTA), thermomagnetic analysis (TMA), transmission electron microscopy (TEM), magnetic measurements (SQUID, vibrating-sample magnetometer) and specific absorption rate measurements (SAR). The synthesized nanoparticles show a size in the range 15–20 nm, exhibited superparamagnetic behavior with a blocking temperature (TB) of approximately 135 K and a room-temperature magnetization of 3–9 emu/g, depending on the composition. The nanoparticles showed a relatively high effective anisotropy constant (Keff) and a significant heating ability in an alternating magnetic field. The synthesis method is straightforward and allows the preparation of homogeneous Ni–Cu alloy nanoparticles with a relatively narrow particle size distribution.
COBISS.SI-ID: 18811926
Pseudomonas aeruginosa is a highly successful nosocomial pathogen capable of causing a wide variety of infections with clone C strains most prevalent worldwide. In this study, we initially characterize a molecular mechanism of survival unique to clone C strains. We identified a P. aeruginosa clone C-specific genomic island (PACGI-1) that contains the highly expressed small heat shock protein sHsp20c, the founding member of a novel subclass of class B bacterial small heat shock proteins. sHsp20c and adjacent gene products are involved in resistance against heat shock. Heat stable sHsp20c is unconventionally expressed in stationary phase in a wide temperature range from 20 to 42°C. Purified sHsp20c has characteristic features of small heat shock protein class B as it is monodisperse, forms sphere-like 24-meric oligomers and exhibits significant chaperone activity. As the P. aeruginosa clone C population is significantly more heat shock resistant than genetically unrelated P. aeruginosa strains without sHsp20c, the horizontally acquired shsp20c operon might contribute to the survival of worldwide-distributed clone C strains.
COBISS.SI-ID: 21447688