Electrochemical behaviour of serpentinite and forsterite in ferri/ferro cyanide benchmark redox system

Serpentinite rock collected near Kopaonik Mountain in Serbia is considered as a multiphase assemblage mostly consisting of mineral lizardite. Forsterite has been obtained by chemical-thermal treatment of grounded sample of serpentinite. Electrochemical features of these two materials were investigated by using modified carbon paste electrode (CPE) which included mixing analytes, graphite powder and parafin oil as a binder and packing the mixture in a Teflon holder. Morphological and structural characteristics of the samples were analyzed by SEM and XRD techniques which revealed presence of certain crystal phases and agregates of irregular shapes sized from 10 to 40 μm. Cyclic voltammetry was employed to study their electrochemical characteristics. The peak current height and peak-to-peak separation showed that the electrochemical reaction is quasi-reversible. Kinetic parameters were derived from Tafel analysis. Calculated kinetic parameters indicated prominent electrocatalytic effect of the minerals for ferri/ferro cyanide redox reaction in aquaeous solutionBook Of Abstracts of 4th Conference of The Serbian Society for Ceramic Material

ELECTROPHORETIC DEPOSITION AS AN EFFECTIVE AND SIMPLE PROCESSING TECHNIQUE FOR FABRICATION OF MAGNESIUM SILICATE HYDRATE (M-S-H) COATINGS ONTO STAINLESS STEEL SUBSTRATES

Magnesium silicate hydrate (M-S-H) was prepared via one-pot hydrothermal synthesis and electrophoretically deposited (EPD) onto stainless steel substrate (Type 304), varying different process parameters. The optimal conditions for the EPD process were found to be as follows. A stable suspension of material was achieved using isopropanol containing 1% water as dispersing medium and Mg-nitrate as charging additive. The best coating was obtained after three successively repeated EPD processes at a voltage of 30 V, accompanied by drying at room temperature between each EPD cycle. The coating showed a thickness of 31 µm and very smooth surface. After calcination at 900 °C coating retains its adherence to the substrate but undergoes a structural transformation from poorly crystallized M-S-H to well-crystallized clinoenstatite phase which is known for its biocompatibility. As a result, it densifies and shrinks giving grainy and slightly rough surface. Structural properties and parameters of the magnesium silicate hydrate (M-S-H) and clinoenstatite were acquired by XRD technique, while morphology was examined by the analysis of SEM micrographs. This study demonstrates that: i) M-S-H can be synthesized through simple hydrothermal route starting from simple, low-cost precursors, ii) EPD process is an effective technique for deposition of M-S-H materials onto stainless steel and iii) inosilicate mineral (clinoenstatite) can be successfully obtained from M-S-H by calcination at 900 °C. HIGHLIGHTSMagnesium silicate hydrate (M-S-H) was prepared via a one-pot hydrothermal synthesis.The optimal conditions for the electrolytic deposition process were determined.Kinetics of the process were investigated using the Hamaker`s equation.Clinoenstatite can be successfully obtained from M-S-H by calcination

Nanoemulsification synthesis route for obtaining highly efficient Ag3PO4 photocatalytic nanomaterial

Nanoemulsion technique based on Ouzo effect was applied for the fast and simple synthesis of Ag3PO4 at room temperature. X-ray powder diffraction analysis and Raman spectroscopy reviled that synthesized powder was single-phase. Using scanning electron microscopy analysis, it was found that the synthesized Ag3PO4 particles were near-spherical shape with an average diameter of 100 nm. The high value for the specific surface area of obtained powder was measured by Brunauer–Emmet–Teller method. Finally, the Ag3PO4 product was used as a photocatalyst for the photodegradation of crystal violet dye in an aqueous solution. Nanoemulsion strategy procedure provides a simple pathway to obtain a highly efficient single-phase Ag3PO4 photocatalyst

Stromalna reakcija u sinkronom in situ i invazivnom urotelnom karcinomu mokraćnog mjehura

The aim was to investigate stromal reaction, including inflammation and stromal desmoplasia in in situ and invasive urothelial carcinoma of urinary bladder and to determine the possible value of reactive stromal changes in the diagnosis of lamina propria invasion. We analyzed specimens from 24 consecutive patients with synchronous in situ and invasive urothelial carcinoma in the same biopsy. Specimens were obtained by transurethral resection, fixed and routinely stained with H&E and Mallory method. Immunohistochemistry was performed by monoclonal antibodies to vimentin, smooth muscle actin and desmin. The intensity of immunostaining was graded semiquantitatively on a scale of 0-3, and expressed as 0 = 0%; 1 = up to 33%; 2 = more than 33% to 66%; and 3 = more than 66% of positive stromal cells. The intensity of inflammation was labeled as 0 = no inflammation, 1 = weak, 2 = moderate, and 3 = dense inflammatory reaction. Mallory trichrome method showed predominantly no staining or weak green staining in 14/24 invasive and 20/24 in situ urothelial carcinomas (p>0.05). There was statistically significantly increased vimentin and smooth muscle actin immunostaining in the stroma of invasive carcinoma as compared with in situ carcinoma (p0,05). Utvrđena je statistički značajno jača reakcija na vimentin i glatkomišićni aktin u stromi invazivnih karcinoma u odnosu na karcinom in situ (p<0,05). Upalna reakcija je bila statistički značajno jača u invazivnim karcinomima (p<0,05). Imunohistokemijska izraženost miofibroblastičnih biljega bila je statistički značajno jača u invazivnim urotelnim karcinomima. Ovakvi rezultati mogu pomoći u dijagnozi invazije lamine proprije u invazivnom karcinomu mokraćnog mjehura

Examination of nanostructured CoMoO4 obtained by glycine nitrate procedure

The synthesis route by solution combustion, a glycine nitrate procedure (GNP) of CoMoO4 nanopowders by a glycine as a fuel and as a complexant was examined concerning the photocatalytic aspects and powder characteristics. The synthesized samples were investigated by differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and nitrogen adsorption method. In this work, we presented a simple and effective method for controlling the composition and morphology of CoMoO4. A single-phase α and β crystalline form of CoMoO4 compound was confirmed by X-ray diffraction (XRD). The photocatalytic testing of CoMoO4 nanopowders showed that these nanostructured materials can be promising solutions in photocatalytic processes toward green chemistry and sustainable development

Structural, Electronic and Mechanical Properties of Superhard B4C from First Principles

Boron carbide (B4C) has attracted great attention as a semiconducting material with excellent properties and has found various technological applications. High hardness value makes it a potentially superhard material as well as a low density, high degree of chemical inertness, high melting temperature, thermal stability, abrasion resistance, and excellent neutron absorption, contributed to the use of boron carbide as an abrasive material for extreme conditions, wear resistance components, body armors and as a nuclear absorber or solid-state neutron detector. However, B4C is known for its unusual structure, bonding, and substitutional disordering whose nature is not yet fully understood, and exhibits brittle impact behavior. In this study we investigated the chain-model structure with an arrangement of 12-boron atom icosahedra and linear 3-carbon atom chains, using available experimental data. We employed the DFT method with LDA and GGA- PBE functional, as implemented in the CRYSTAL17 software package. Electronic properties of boron carbide have been investigated by calculating the density of states (DOS) and band structure. Calculated mechanical properties have been investigated: bulk modulus, shear modulus, Young modulus, Poisson’s ratio, hardness, and elastic tensor constants, and compared with available experimental data

DFT study of new hybrid organic-inorganic perovskites: guanidinium-BX3 substituted by B=(Sr2+, Ca2+, Mg2+, Be2+) and X=(Cl-, F-)

Program and book of abstracts / 2nd International Conference on Innovative Materials in Extreme Conditions i. e. (IMEC2024), 20-22 March 2024 Belgrade, Serbia

Structure Prediction and Mechanical Properties of Silicon Hexaboride on Ab Initio Level

Silicon borides represent very appealing industrial materials for research owing to their remarkable features, and, together with other boride and carbide-based materials, have very wide applications. Various Si&ndash;B phases have been investigated in the past, however a limited number of studies have been done on the pristine SiB6 compound. Structure prediction using a data mining ab initio approach has been performed in pure silicon hexaboride. Several novel structures, for which there are no previous experimental or theoretical data, have been discovered. Each of the structure candidates were locally optimized on the DFT level, employing the LDA-PZ and the GGA-PBE functional. Mechanical and elastic properties for each of the predicted and experimentally observed modifications have been investigated in great detail. In particular, the ductility/brittleness relationship, the character of the bonding, Young&rsquo;s modulus E, bulk modulus B, and shear modulus K, including anisotropy, have been calculated and analyzed

Energy landscape exploration of the novel CrSi2N4 compound

Program and book of abstracts / 2nd International Conference on Innovative Materials in Extreme Conditions i. e. (IMEC2024), 20-22 March 2024 Belgrade, Serbia