Predrag Jovanic

Emulsion Stability Evaluation Using Fractal Dimensions Approach

There are many developed strategies for evaluating emulsion stability, aimed at determining the life circle of emulsions. Most of them are based on rheological properties of emulsions. There are, however, very few based on direct emulsion observations. In this paper we present a developed method for the emulsion stability evaluation by direct observation of optical emulsion properties. We propose the fractal dimension approach as a stability quantification measure. The method is based on the measure of emulsion transmittance properties, which are directly dependent on the emulsion stability at the moment of measurement. The oil in water emulsion was used as a test emulsion. The system is classified as stable emulsion and our intention was to find the moment when it starts to break. Emulsion transmittance properties were measure applying a system for acquisition of visual information, which is based on a CCD camera and a fast PC configuration equipped with the capturing software. The acquired sets of visual information were analyzed by the OZARIA software package. The fractal dimensions were determined by the box counting method. For these experiments, 100 boxes of different sizes were used. Experimental emulsions were measured after 7, 14, 21 and 28 days from the moment of creation. A slight increase in fractal dimensions was observed, which indicates that the emulsions are still in the stable region, or from the fractal point of view emulsion are still regular and no significant irregularities were observed. From the first experiments the applied methodology proved to be sensitive enough to be used for emulsions stability evaluation.

The Characterization of the Selected Trees Damaged During Severe Weather Episode on the Mountain Avala (Serbia) Using IR Thermography, ICP-OES, and Microbiological Analysis

Selected plants of white fir and lime, damaged during severe weather episode on the mountain Avala (Serbia) in summer 2014, were analyzed and characterized (including their spatial soil samples) by inductively coupled plasma optical emission spectroscopy (ICP-OES), infrared (IR) thermography, and microbiological method such as enumeration of cultivable microorganisms. The results obtained from chemical and microbiological analyses provided valuable information on possible biotic and abiotic stressors such as soil fungi and heavy metals, which could affect the health status of trees, while IR thermography visualized this status in a very specific and effective way. The results of ICP-OES analysis clearly showed that the investigated heavy metals (Cu, Zn, Pb, As, Cd, and Ni) were less likely crucial factors responsible for ruined health status of damaged trees. The role of soil fungi was not clear, since the results of microbiological analysis only provided evidence that their amounts in all investigated soil samples were within normal ranges as well as that their amounts in the corresponding samples of the uprooted trees were much greater than in the case of snapped trees. Therefore, further molecular characterization of microorganisms should be performed to identify if pathogenic species are present and clarify their role. Nevertheless, all used methods, especially IR thermal imaging as a totally non-invasive, fast and very comfortable technique, can be recommended as very useful in preventive screening of the trees’ health status and for early detection of tissue decay that usually hamper trees survival or resistance to extreme weather events.

New approach for water quality analysis and modeling

Watercourses present a special case of water reservoirs. Regardless to the method of their investigation, there is still a search for the convenient method for processing of collected measurements of water quality parameters. Research direction was defined by the EU directive framework for aquatic bodies. Taking into consideration the existing methods for water quality analysis, this paper presents a proposal of a new method for analysis and modeling the aquatic body behavior. The measurements conducted at five stations on the river Ibar in the period from 2007 to 2012 are used as a basis. The basic method is based on multivariable analysis of unevenly time spaced measuring data. The basis was the correlation analysis that defined dependent parameters for determination the SWQI indices. Analyses have shown that the obtained results can be used for establishing an integral monitoring the water quality of aquatic system of the river Ibar. Also, they pointed out the possible directions for measurement and analysis upgrading.