Temperature dependence of electric properties of GO and GO/WPA films on interdigital electrodes

In sensor devices the material of choice should be highly dependent on perturbation of environmental parameters. In order to achieve good sensitivity and selectivity of sensing devices to temperature, humidity or concentration of different gasses, the materials with adjustable properties are highly desirable. Electric properties of graphene oxide (GO) can be easily tuned by modification of surface chemistry and anchoring of functional compounds onto its two-dimensional structure. Prior to application of sensing device, research and development of materials system is the most essential step. In this work, the formation of GO and GO/12-tungstophosphoric acid (WPA) films with 6 wt.% of WPA on interdigital electrodes was investigated by variation of dip-coating parameters (receding angle and time between steps). Obtained films were thermally reduced in argon atmosphere after which optical microscopy was used to evaluate morphology and stability of deposited GO and GO/WPA films. Impedance spectroscopy was used to investigate the electric properties of the obtained films in range from 10 Hz to 100 kHz. Measured impedance values were correlated to the degree of material detachment and deposition parameters i.e. films showing the lowest impedance values had the smallest area of detached film. Additionally, impedance values were measured depending on the environment temperature which showed that GO/WPA films exhibit the lowest impedance values and good sensitivity to changes of temperature making it good a candidate for sensing devices.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Investigating the influence of hydrothermal treatment on oxygen functional groups in graphene oxide-based nanocomposites

Different hierarchical ordering of nanomaterials, either as individual components or in the form of nanocomposites, is one of the approaches used for the development of supercapacitors. In this work, the effect of hydrothermal treatment on oxygen functional groups of nanocomposites between graphene oxide (GO), 12-tungstophosphoric acid (WPA), and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) was examined. The mentioned materials were hydrothermally treated for 4, 8 and 12 hours at 180 °C in order to understand how interaction between the components is influencing development of surface chemistry. The results of Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), and temperature-programmed desorption (TPD) are showing the surface and structural changes of GO (individually and in nanocomposite) as a result of hydrothermal treatment. Both FTIR and RAMAN confirm the presence of WPA and PTCDA. Additionally, it appears that hydrothermal treatment has no impact on the structural changes in PTCDA, which is consistent across various temperature conditions. TPD results indicate that prolonged hydrothermal treatment leads to a gradual increase of the number of functional groups of GO. However, the number of desorbed groups is influenced by the WPA and PTDCA components. This research offers new insights into GO, WPA, and PTCDA interactions which can have useful implications for development of electrochemical supercapacitors.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Solvothermaly synthesized copper doped bismuth vanadate

Photoeletrochemical (PEC) water splitting is a promising method for clean energy production and different oxide materials have been explored to find the right solution. Among them, as one of the most promising photoanode materials, bismuth vanadate (BiVO4) has attracted a lot of attention due to the suitable band gap edge alignment, lowcost synthesis method and great visible light harvesting features. Nowdays, research related to the BiVO4 is mostly oriented towards repairing poor charge transfer properties which exist due to the high rate of electron–hole recombination. Metal doping is one of the strategies to improve these intrinsic drawbacks. Herein, we report physicochemical properties of solvothermaly sinthesized pristine BiVO4, 1%-, 2.5%- and 5%- Cu-doped BiVO4 powders at 180 ºC for 8 h. X-ray diffraction (XRD) study indicates that, depending on the degree of doping, material exists in monoclinic or tetragonal scheelite phase. Pure monoclinic phase was formed in a case of pristine, 1%- and 2.5%- Cu doped samples. After doping with 5 %, phase transition occurred and material showed tetragonal phase. Scanning electron microscopy (SEM) reveals that samples with monoclinic phase consists of worm-like and prismatic structures while tetragonal samples exhibited spherical shape. Furthermore, structure was examined with Raman and FTIR spectroscopy. The results were in accordance with diffraction study where band positions were well matched with phase composition. Optical properties were characterized with UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. Monoclinic samples showed band gap around 2.4 eV, while sample with tetragonal phase has band gap around 2.8 eV. PL showed that that monoclinic samples possess better recombination features than tetragonal ones. Photoelectrochemical measurements suggest that material is sensitive towards visible light and, after doping, improved its performance towards oxygen evolution reaction.8th Conference of Young Chemists of Serbia; 29th October, Belgrade, Serbi

Teaching in conditions of difficult knowledge transfer due to the state of emergency caused by the pandemic

Introduction/purpose: This paper presents the transformation of the current, classical approach to teaching. Online platforms enable students with and without disabilities to follow classes without hindrance during the lecture period. After the lecture, they are allowed to view video and presentation materials. The main advantage of this way of teaching is the possibility of attending classes from any location and from any device; it is only important to be connected to the Internet. Methods: Full integration with the already existing Faculty Information System has been performed. The paper describes a new approach to teaching and illustrates the expected benefits of online teaching. The platforms used in this integration are Microsoft Azure, Microsoft Office 365 Admin, Microsoft Teams, Microsoft Stream and Microsoft SharePoint. Results: The result of the test of work with students showed that by introducing a system for online teaching, we directly affect the improvement and quality of teaching. Conclusion: Considering all the results, it can be concluded that the transition to the online way of teaching allows end listeners a comprehensive transfer of knowledge as well as re-listening to the same. This model can be used for an unlimited number of users in all Institutions, regardless of whether the field of activity of these Institutions is of educational origin.info:eu-repo/semantics/publishedVersio

Language of Advertisement in the 19th, 20 th and 21st Centuries

Tema je ovog rada jezik oglasa 19., 20. i 21. stoljeća. U prvom dijelu rada određuju se i opisuju reklamne poruke i njihova retorika. Reklamna poruka određena je cijelim nizom različitih čimbenika – u njezinu kreiranju značajan je položaj same reklame u odnosu na ostale informacije koje se u tome mediju nude. Pri određivanju pripadnosti reklamnih poruka pojedinom funkcionalnom stilu prikazane su odlike reklamnih poruka koje odgovaraju odlikama određenih funkcionalnih stilova. O jezičnim se ulogama raspravlja preuzimajući nazivlje i osnovne odrednice Romana Jakobsona. Odlike su potkrijepljene prikazom primjera reklamnih poruka preuzetih, većinom, iz Branislava, Narodne obrane, Hrvatskoga lista i Glorije. U radu su opisana i pojedina pravopisna i semantička obilježja reklama 19., 20. i 21. stoljeća te primjer zabranjenih reklamnih poruka iz 20. stoljeća. Nakon svega istraženog u okviru rada izveden je zaključak o jeziku oglasa u trima stoljećima

Evaluacija performansi savremenih sistema distribucije znanja

U ovoj disertaciji je prikazana analiza transformacije klasičnog pristupa nastavi u novi, savremeniji onlajn metod. Glavna prednost ovakvog načina prenosa znanja ogleda se u velikoj fleksibilnosti kako slušaoca tako i predavača. Slušaoci i predavači imaju mogućnost da prisustvuju predavanju sa bilo koje fizičke lokacije i sa bilo kog uređaja, uz preduslov obezbeđene Internet konekcije. Pri istraživanju prenosa znanja izvršena je kompletna integracija testirane platforme sa već postojećim informacionim sistemom. Prikazane su mane kao i načini za njihovo prevazilaženje. U disertaciji su ilustrovane prednosti onlajn nastave. Sve definisane promene postojećeg sistema su realizovane na osnovu anketnog ispitivanja studenata od strane menadžmenta univerziteta. Rezultat trogodišnjeg angažmana sa studentima i predavačima doveo je do rezultata da uvođenjem onlajn sistema za realizaciju nastave pozitivno utičemo na poboljšanje i kvalitet obrazovanja. U navedenom periodu tokom integracije korišćene su Microsoft Office 365, Microsoft SharePoint, Microsoft Azure, Microsoft Stream, Microsoft Teams, kao i druge platforme. Navedene platforme omogućile su realizaciju u fizičkom, onlajn i hibridnom obliku. Uvidom u dobijene rezultate dolazi se do zaključka da je prelazak na onlajn način prenosa znanja omogućio krajnjim slušaocima veoma kvalitetan i sveobuhvatan prenos znanja kao i mogućnost ponovnog preslušavanja istog. Navedeni model je moguće implementirati na neograničenom broju potencijalnih korisnika u različitim institucijama nevezano od toga da li je polje delovanja tih institucija obrazovnog porekla

Language of Advertisement in the 19th, 20 th and 21st Centuries

Tema je ovog rada jezik oglasa 19., 20. i 21. stoljeća. U prvom dijelu rada određuju se i opisuju reklamne poruke i njihova retorika. Reklamna poruka određena je cijelim nizom različitih čimbenika – u njezinu kreiranju značajan je položaj same reklame u odnosu na ostale informacije koje se u tome mediju nude. Pri određivanju pripadnosti reklamnih poruka pojedinom funkcionalnom stilu prikazane su odlike reklamnih poruka koje odgovaraju odlikama određenih funkcionalnih stilova. O jezičnim se ulogama raspravlja preuzimajući nazivlje i osnovne odrednice Romana Jakobsona. Odlike su potkrijepljene prikazom primjera reklamnih poruka preuzetih, većinom, iz Branislava, Narodne obrane, Hrvatskoga lista i Glorije. U radu su opisana i pojedina pravopisna i semantička obilježja reklama 19., 20. i 21. stoljeća te primjer zabranjenih reklamnih poruka iz 20. stoljeća. Nakon svega istraženog u okviru rada izveden je zaključak o jeziku oglasa u trima stoljećima