Papers by Branka Kaludjerovic
DOAJ (DOAJ: Directory of Open Access Journals), 2009
Nanoparticles, Nanocapsules, Nanofibers, Nanoporous Structures, and Nanocomposites, Volume II, 2016
Influence of chemical agents on the surface area and porosity of
Metallurgical and Materials Engineering, 2020
Carbon materials with developed porosity are usually used as supports for platinum catalysts. Phy... more Carbon materials with developed porosity are usually used as supports for platinum catalysts. Physico-chemical characteristics of the support influence the properties of platinum deposited and its catalytic activity. In our studies, we deposited platinum on carbon fibrous like materials obtained from platanus seeds - achenes. The precursor was chemically activated with different reagents: NaOH, pyrogallol, and H2O2, before the carbonization process. Platinum was deposited on all substrates to study the influence of the substrate properties on the activity of the catalyst. Carbon materials were characterized by nitrogen adsorption/desorption isotherms measurements, X-ray diffraction, and scanning electron microscopy. It was noticed that the adsorption characteristics of carbon support affected the structure of platinum deposits and thus their activity.
Platinum supported on high surface area carbon material is one of the most intensively studied ca... more Platinum supported on high surface area carbon material is one of the most intensively studied catalysts. However, physicochemical characteristics and surface chemistry of carbon influence properties of the support itself as well as of a catalyst. In our studies we deposited platinum on hollow fibers with or without carbon cryogel. Carbon materials were characterized by nitrogen adsorption/desorption isotherms measurements, X-ray fluorescence spectrometry and scanning electron microscope. Deposition of platinum was performed chemically and electrochemically. The electrochemical deposition was performed on the grinded samples at the same conditions for all substrates with the aim to study the activity of the catalyst. It was noticed that the nature of carbon support affected structure of platinum deposits and thus their activity.
Science of Sintering, 2020
Carbonaceous materials as well as its form functionalized with metallic silver have been prepared... more Carbonaceous materials as well as its form functionalized with metallic silver have been prepared by hydrothermal carbonization of fructose. Results are presented to show that nanostructured silver was obtained through the functionalization process. The carbonaceous materials were characterized by: nitrogen adsorption/desorption measurement, XRD, SEM/EDS and FTIR. Samples functionalized with silver were analyzed by: XRD and SEM/EDS. The XRD analysis showed that the carbonaceous materials functionalized with silver by hydrothermal carbonization process were successfully performed. Size of silver particles was found to be approximately 32 nm, indicating formation of nanostructure. All samples were tested as an antimicrobial agent for water disinfection. Presence of nanostructured silver in the sample containing 1 mg/mL carbonaceous materials significantly decreased the number of CFU (dCFU = 97.33 %) if compared to the same sample containing the same amount of carbonaceous materials but without of silver (dCFU 65.33 %).
Zastita materijala, 2017
Optička molekularna anizotropija materijala i Rayleighevo rasejanje IZVOD Rayleighevo rasejanje i... more Optička molekularna anizotropija materijala i Rayleighevo rasejanje IZVOD Rayleighevo rasejanje izraženo formalizmom depolarizovanih i polarizovanih komponenti pruža mogućnosti za analizu optičke molekularne anizotropije za tečne materijale (čiste, razblažene rastvore sa velikim i malim molekulima). Postoje razni uređaji za merenje rasejanja, ali se i sa aparaturama sa statičkim rasejanjem dobija dosta podataka. Primenom He Ne lasera na osnovnom prelazu 632,8nm na uređaju laboratorijskog tipa, mereno je rasejanje organskih rastvarača karakterističnih za etaloniranje. Ova merenja su poslužila i za poređenje karakteristika materijala dobijenih sa spontanim izvorima i kvantnim generatorima-laserima. Na osnovu potvrde, ocenjena su i merenja manje poznatih materijala i od interesa za biološke procese (fitola i srodnih jedinjenja za sticanja uvida u ponašanje fitil grupe).
Science of Sintering, 2018
In presented paper, influence of temperature, precursor concentration and different hydroxides on... more In presented paper, influence of temperature, precursor concentration and different hydroxides on properties of activated carbon obtained from saccharose were investigated. The samples were prepared by hydrothermal treatment and activated using KOH, NaOH and LiOH. Two saccharose concentrations (0.5, 1.0 mol/dm3) and three temperatures (160, 200, 240 ?C) were changed in hydrothermal treatment. Activation processes were performed at 750?C under N2 atmosphere. Samples were characterized by X-ray powder diffractometry, elemental analysis, N2 adsorption-desorption measurements, Fourier-transform infrared spectrometry, scanning electron microscopy and thermal analysis. The obtained samples were tested for potential application in dyes removal from water solutions.
JOURNAL OF ENGINEERING & PROCESSING MANAGEMENT, 2019
Scattering of optical photons from the view of parallel methods related to absorption, scattering... more Scattering of optical photons from the view of parallel methods related to absorption, scattering, fluorescence, reflection with inclusion of the polarization states of laser beams from experiment and theory give many possibilities for obtaining indirect data on material, processes, and dynamics. As a method with minimal perturbations, if low power beams are involved, certain type of data is provided. In fundamental dependences of various material properties, many phenomenological and basic laws are covered. Several coupled variables, primarily with the processes of scattering, pointing out further possibilities for linking the obtained theoretical or experimental results were presented. By including simulations, this associates with biological environments / variables for properties equivalent to defined tissues, cells, and characteristics. Along with selected formalisms including Stokes vectors and scattering matrices, a biological cell as an object can be monitored in time and in...
Composites Part B: Engineering, 2017
for the synthesis, processing and characterization of materials for use in extreme conditions "CE... more for the synthesis, processing and characterization of materials for use in extreme conditions "CEXTREME LAB,
Zastita materijala, 2015
Nanostructures of noble metals (Pt and Ag) on carbon support were prepared from fructose and solu... more Nanostructures of noble metals (Pt and Ag) on carbon support were prepared from fructose and solution of the Nobel metal salts (H 2 PtCl 6 6H 2 O or AgNO 3) under hydrothermal conditions. Commercial fructose (C 6 H 12 O 6) acts as the carbon source and reducing agent and noble metal salts is a source of the metal to be incorporated in the new formed carbon material structure. The crystalline structure was examined by X-ray diffraction (XRD) and morphology investigated by scanning electron microscopy (SEM). The crystallite size of the deposited particles could be estimated by evaluating the line width of the Bragg peak applying the Scherrer method. All the XRD patterns clearly show the five main characteristic peaks of the face-centered cubic (fcc) crystalline for both Pt and Ag crystallite. The obtained Pt crystallite sizes were below 5.5 nm, while the Ag crystallite sizes were about 32 or 34nm.
Zastita materijala, 2015
Some considerations related to quantum electronics, acoustics and science of material based on ex... more Some considerations related to quantum electronics, acoustics and science of material based on experiment and theory The coupling of some fundamental sciences and issues arising from it are considered in this paper. The transport and optical characteristics belong to nowadays problems of material science. Some measurements and their interpretations for chosen condensed materials are considered. Various processes, which include directly optical and acoustic processes, are measured for solid and liquid materials. After obtained principal issues of measurement, coupling with them is performed. Principal links include dielectric, resistive, optical and acoustical performances. Nonlinear optical contribution up to optical-laser breakdown can be evaluated from linear data. Micellar laser scattering cover transient effects and is one of the topics in many sciences (including biology and ecology).
Zastita materijala, 2015
Structural properties of carbon microspheres obtained by hydrothermal treatment of fructose A car... more Structural properties of carbon microspheres obtained by hydrothermal treatment of fructose A carbon-rich solid product has been synthesized by hydrothermal treatment from fructose with HNO 3 at temperature of 140°C. The concentration of the precursor was changed in order to investigate how its change influences formation of carbon microspheres. pH value for every sample was the same, i.e. 1. The formation of the carbon rich solid through the hydrothermal carbonization of fructose is the consequence of dehydration reactions. Obtained carbon material is made of spherical micrometer-sized particles with the diameter in the 1-6 µm range, which can be modulated by modifying the concentration of fructose in solution. The best results are obtained with smaller concentrations of fructose. Spherical particles have more regular shape and they are less agglomerated. The structure and surface chemical properties of obtained material were characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectra and elemental analysis.
International Journal of Clothing Science and Technology, 2015
Purpose – The purpose of this paper is to present the results of interaction occurring during the... more Purpose – The purpose of this paper is to present the results of interaction occurring during the exposition of some specific carbon textile materials obtained in laboratory conditions to beams of various laser types. Design/methodology/approach – Carbon fabric materials – fiber, felt and cloth – obtained from different precursor materials and prepared at various process conditions (oxidized, partially carbonized, carbonized, graphitized), were exposed to pulses of various lasers (Nd3+: YAG, alexandrite, ruby). Findings – Depending on the laser power, plasma and destructive phenomena occurred. In the case of an interaction between a Nd3+: YAG laser beam and specimens of thickness in millimeter range, the authors have estimated the threshold of the energy density for drilling and discussed the possible models of the interaction. Research limitations/implications – The results have implications in the estimations of quality as well as in the improvement of material processing, giving ...
Zastita materijala, 2014
Optical material performances, measurement by laser implementation and interpretations Optical ma... more Optical material performances, measurement by laser implementation and interpretations Optical material performances along with main response functions belong to nondestructive measurements. Lasers brought new techniques beside accuracy increase. Nonlinear techniques introduced new solutions. These could be used in industry, biomedicine, and ecology with fast material description in various phases. The paper is elaborating optical characteristics in various phases and descriptions (purity, dynamics and optical breakdowns). From the scattering point of view, water represented medium, unstable when pure comparing to organic etalons. As solvent for macromolecules and polymers it is difficult to be observed. In solutions with surface active materials, the stability of the formation is important. A few aspects of experiments and scattering theories (static and dynamic) of mono and polychromatic light including nonlinear approaches were analyzed.
Chemical Industry and Chemical Engineering Quarterly, 2015
Laser beam interaction with carbon based material (glassy carbon) is analyzed in this paper. Nd3+... more Laser beam interaction with carbon based material (glassy carbon) is analyzed in this paper. Nd3+:YAG laser beam (1.06?m i.e. near infrared, NIR range) in ms regime with various energy densities is used. In all experiments, provided in applied working regimes, the surface damages have occurred. The results of laser damages are analyzed by light and electron scanning (SEM) microscopies. Program Image J is executed for quantitative analysis of generated damages based on micrographs obtained by light and SEM microscopes. Temperature distribution in exposed samples is evaluated by numerical simulations based on program packages COMSOL Multiphysics 3.5 in limited energy range.
OPTIKA '98: 5th Congress on Modern Optics, 1998
ABSTRACT It is well known that application of stimulated light may influence phase modifications ... more ABSTRACT It is well known that application of stimulated light may influence phase modifications and changes of carbon structure. These effects of laser irradiation, in different working regimes and atmospheres, are widely investigated for fullerenes and diamond structure, but for many other carbon materials, are not. In the presented experiments, we treated by Q-switch ruby and Nd3+ YAG laser beams different carbon clothes, produced by pyrolysis (T <EQ 1000 degree(s)C) of cellulose materials in inert atmosphere. The materials are interesting for many applications, including medical. The laser pulse energy was of order of 0.1 - 1 J, in one, or multi-pulse regime. Focused and unfocused beams were used to induce damages and oxidation of sample surfaces. the damages were analyzed by scanning electron microscopy and specific area is measured by Brunauer, Emmet and Teller method, before and after the interaction. Materials exhibited differences in the damaging level and the fiber breaking thresholds. Mechanisms of laser interaction leading to oxidation of carbon type materials are discussed, and the necessary experimental conditions for intended changes are analyzed.
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Papers by Branka Kaludjerovic