Mića Jovanović

Modeling selected emulsions and double emulsions as memristive systems

The recent development in basic and applied science and engineering of finely dispersed systems is presented in general, but more attention has been paid to the liquid-liquid finely dispersed systems or to the particular emulsions and double emulsions. The selected systems for theoretical and experimental research were emulsions and double emulsions that appeared in the pilot plant for extraction of uranium from wet phosphoric acid. The objective of this research was to try to provide a new or different approach to elaborate the complex phenomena that occur at developed liquid-liquid interfaces. New concepts were introduced, the first is a concept of an entity, and the corresponding classification of finely dispersed systems and the second concept consider the introduction of an almost forgotten basic electrodynamics element memristor, and the corresponding memristive systems. Based on these concepts a theory of electroviscoelasticity was proposed and experimentally corroborated using the selected representative liquid-liquid system. Also, it is shown that the droplet, and/or droplet-film structure, that is, selected emulsion and/or double emulsion may be considered as the particular example of memristive systems.

Breaking of double emulsions based on electrohydrodynamics principles.

This research focuses on the modeling of the liquid-liquid dispersed system, including particular insight on the electrocoalescence (EC) process that occurs during the breaking of double emulsions. The representative system, used in this work, was taken from the pilot plant for solvent extraction of uranium from wet phosphoric acid. The chosen framework required for elucidation of the EC process is based on the electrohydrodynamic (EHD) principles. During the model development it was necessary to consider several theoretical concepts for easier understanding and description of the related events. The first is the concept of entities, and corresponding classification of finely dispersed systems. The second concept is an introduction of almost forgotten basic electrodynamics element the memdiode or memristor as a current controlled device, and corresponding memristive systems. Hence, the conclusions that may be withdrawn from the presented results and findings could enable easier designing of the solutions for a breaking of double emulsions problems, that is, the entrainment problems that may arise in some pilot or industrial plants. Finally, the perspectives and the remaining challenges, considering the here discussed concepts and model based on the EHD principles, are mentioned.

Landfill design: need for improvement of water and soil protection requirements in EU Landfill Directive

This paper deals with environmental policy issues related to a landfill design. The final product of numerous waste treatments should be placed on a landfill. Before waste disposal, the ground should be protected by a mineral layer with properties required by the related regulation. In order to prevent environment pollution, EU adopted the Landfill Directive 1999/31/EC. The most important technical requirements related to the characteristics of the layer material are water permeability and thickness. The performed comparative national regulatory analysis raised the question of the need for more uniform elaboration of the directive requirements over the whole European Union area (including EU candidates). The choice of the material for the impermeable mineral layer, which should be made during landfill design, is a very important decision. Methods for the determination of the permeability coefficient were analysed, showing that the Directive should define hydraulic gradient as a physical quantity and define its value through measurement of the permeability coefficient. The paper analyses whether some parts of the Directive, as landfill design BAT and base for national legislative acts, require further elaboration in order to provide sufficient information about proper protection of soil and water. Using integrated approach, seven amendments on the directive annex I were suggested related to (a) the meaning of the term artificially established geological barrier, (b) layer thickness, (c) water permeability coefficient determination, (d) mineral layer lifecycle, (e) the meaning of the term sealing and (f) leaching control of material joints.

Waste reduction algorithm used in environmental impact assessment: Case study of bitumene production

Waste reduction algorithm - WAR is a tool helping process engineers for environmental impact assessment. WAR algorithm is a methodology for determining the potential environmental impact (PEI) of a chemical process. In particular, the bitumen production process was analyzed following three stages: a) atmospheric distillation unit, b) vacuum distillation unit, and c) bitumen production unit. Study was developed for the middle sized oil refinery with capacity of 5000000 tones of crude oil per year. Results highlight the most vulnerable aspects of the environmental pollution that arise during the manufacturing process of bitumen. The overall rates of PEI leaving the system (PEI/h) - Iout PEI/h are: a) 2.14105, b) 7.17104 and c) 2.36103, respectively. The overall rates of PEI generated within the system - Igen PEI/h are: a) 7.75104, b) -4.31104 and c) -4.32102, respectively. Atmospheric distillation unit have the highest overall rate of PEI while the bitumen production unit have the lowest overall rate of PEI. Comparison of Iout PEI/h and Igen PEI/h values for the atmospheric distillation unit, shows that the overall rate of PEI generated in the system is 36.21% of the overall rate of PEI leaving the system. In the cases of vacuum distillation and bitumen production units, the overall rate of PEI generated in system have negative values, i.e. the overall rate of PEI leaving the system is reduced at 60.11% (in the vacuum distillation unit) and at 18.30% (in the bitumen production unit). Analysis of the obtained results for the overall rate of PEI, expressed by weight of the product, confirms conclusions.Waste reduction algorithm (WAR) is a tool designed to help process engineers for environmental impact assessment. The WAR algorithm is a methodology for determining the potential environmental impact (PEI) of a chemical process. In particular, the bitumen production process was analyzed in the following three stages: a) atmospheric distillation unit, b) vacuum distillation unit, and c) bitumen production unit. The study was developed for a middle-sized oil refinery with a capacity of 5000000 t of crude oil per year. The results highlight the most vulnerable aspects of the environmental pollution that arise during the manufacturing process of bitumen. The overall rates of PEI leaving the system (PEI/h) - Iout PEI/h are: a) 2.14×105, b) 7.17×104 and c) 2.36×103, respectively. The overall rates of PEI generated within the system - Igen PEI/h are: a) 7.75×104, b) -4.31×104 and c) -4.32×102, respectively. The atmospheric distillation unit had the highest overalll rate of PEI while the bitumen production unit had the lowest overall rate of PEI. Comparison of Iout PEI/h and Igen PEI/h values for the atmospheric distillation unit showed that the overall rate of PEI generated in the system was 36.21% of the overall rate of PEI leaving the system. In the cases of vacuum distillation and bitumen production units, the overall rate of PEI generated in system had negative values, i.e., the overall rate of PEI leaving the system was reduced at 60.11 (in the vacuum distillation unit) and at 18.30% (in the bitumen production unit). Analysis of the obtained results for the overall rate of PEI, expressed by weight of the product, confirmed the conclusions.

Upotreba biološkog monitoringa u cilju zaštite životne sredine

Various natural phenomena, such as earthquakes, volcanic activity, or floods, but also changes due to human activity, can influence the health of human beings. The inability of humankind to, using basic principles of ecology, reduce their negative influence on the living environment can be considered one of the biggest failures of the 21st century. Having in mind that the human factor is one of the biggest causes of changes in biological systems, managing this influence requires thorough assessment and control, which is most easily done using biological monitoring. The aim of this paper is to present the basic principles of biological monitoring, as well as demonstrate the most useful methods and examples of their use in health impact assessment.

Defining the Needs and Developing an Informational System for the Monitoring and Assessment of Landfil Gas for Municipal Landfils

Serbia is the largest country in the region, and with a little over 7.5 million people has more than 3600 waste dupmsites. When low level of recycling (less than 10%) and existance of only 7 larger landfils is taken into account, it becomes clear that there is a need for upgrading the waste management in our country in order to prevent the negative influences on the environment and human health, but also to satisfy the requirements necessary to join the European Union. There are many models alowing to estimate the quantities of landfil gas, and several solutions exist in the form of Excel sheets, but there is no integrated software solution which would facilitate monitoring of municipal waste landfilling, estimating emissions, and reporting. The aim of this paper is to analyze the needs for a software solution of this kind and present the basic steps in the development of this software solution.

Ispitivanje mogućnosti uklanjanja sintetskih boja u mikroreaktorskim sistemima

Dyes are an important class of pollutants. Usage of synthetic dyes in the textile industry as a consequence has high amounts of colored wastewater. Before discharging, colored water has to be treated to achieve quality prescribed by law. Decolorization is a complex process which includes application of different chemical reagents which leads to additional water contamination. Our earlier works showed success in decolorization of wastewater contaminated with Reactive Orange 16. This paper deals with possibility of decolorization of wastewater, contaminated with Basic Yellow 28 and Acid Blue 111, in microreactor system using diluted solution of NaOCl.

Mogućnost odgovara zdravstvenih ustanova na industrijske akcidente-primer zdravstvene ustanove u opštini Obrenovac

Based on the Hyogo and Sendai Framework for Disaster Risk Management caused by natural or human factors, a study was conducted on the territory of Obrenovac municipality regarding the readiness of health care facilities to respond to potential industrial accidents. Local health care facilities are public service provider which often represent the primary level in the hierarchy of providing health care services to the local population in case of smaller or larger industrial accidents. Through our paper we will present the methodology used for calculating the hospital safety index defined by the World Health Organization, the possibility to apply this method of evaluation on health care facilities in Serbia, the preliminary results of our studies and suggested procedures for overcoming organiza-tional, architectural, and construction problems in the primary health care facility of Obrenovac.

Shrinking core models applied to the sodium silicate production process

The sodium silicate production process, with the molar ratio SiO2/Na2O = 2, for detergent zeolite 4A production, is based on quartz sand dissolving in NaOH aqueous solution, with a specific molality. It is a complex process performed at high temperature and pressure. It is of vital importance to develop adequate mathematical models, which are able to predict the dynamical response of the process parameters. A few kinetic models were developed within this study, which were adjusted and later compared to experimental results. It was assumed that SiO2 particles are smooth spheres, with uniform diameter. This diameter decreases during dissolving. The influence of particle diameter, working temperature and hydroxide ion molality on the dissolution kinetics was investigated. It was concluded that the developed models are sufficiently correct, in the engineering sense, and can be used for the dynamical prediction of process parameters.