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In this paper the influence of ventilation air velocity on properties of metal working fluids (MWF) aerosol/mist is presented. Aerosol characteristics were monitored in the chamber as well as at the entrance of ventilation pipe by optical particle size analyzer. Aerosol was generated from 6% water emulsion of three commercial MWF. Four different velocities, less than the velocity of secondary atomization, were examined (1, 3, 6, 8 m/s). Droplets size distribution, mass concentration (mg/m3), as well as number concentration (P/cm3) were measured and analyzed. From the results obtained it may be seen that coalescence is more pronounced as the velocity increases, although the number concentration decreases, due to higher air dilution. Therefore, more droplets are in a whirling motion at higher air velocities, hence more random collisions are possible. Further analysis shows that there is one value of air velocity under which the maximum difference between the aerosol in chamber and the aerosol at the entrance of the pipe can be observed. This velocity could be named specific velocity and depends on the given aerosol properties. It could be assumed that specific velocity is conditioned by the properties of oil from which emulsion is prepared. Oil viscosity and molar mass have greatest influence on the specific velocity.

This work investigates influence of different process parameters such as transmembrane pressure, flow rate and concentration of wheat starch suspension on the average permeate flux and permeate flux decline. Used membrane in all experiments was 19 channels ceramic membrane with 0.2 μm pore size. Experimental results were analyzed using response surface methodology. It is observed that the significant average permeate flux enhancement of 200% was achieved by the increase of the transmembrane pressure, while the increase of flow rate and concentration affected the increase in average permeate flux in the range of 40-100%. Permeate flux decline was almost independent of the transmembrane pressure, but the increase of the flow rate, as well as the decrease of the concentration led to decrease of permeate flux decline in the range of 20-50%.

Methods that can provide adequate accuracy in the estimation of variables from incomplete information are desirable for the prediction of fermentation processes. A feed-forward back-propagation artificial neural network was used for modelling of thick juice fermentation. Fermentation time and starting sugar content were usedas input variables, i.e. nodes. Neural network had one output node (ethanol content, yeast cell number or sugar content). The hidden layer had nine neurons. Garson's algorithm and connection weights were used for interpreting neural network. The inadequacy of Garson's algorithm can be seen by comparing with the results of regression analysis, which indicates that the influence of the fermentation time is higher. A better agreement of the results was obtained using network connection weights, a method that can be used to determine the relative importance of input variables.

General trend of free trade at the regional level as well as in the direction of European Union has motivated sugar factories located in Serbia to invest into technologies that are more efficient in order to make their products more competitive in the markets of Europe. Until 2005, the project of energy efficiency improvement in Serbian sugar factories was conducted in Crvenka and Žabalj. Now, they have energy consumption around 1 MJ/kg beet, in contrast to the previous consumption of 1.2 up to 1.5 MJ/kg beet. Further improvements are possible but investments would be high. A result of measurements taken during 2006, after the sugar factory "Donji Srem" - Pećinci was reconstructed showed that a considerable saving has been achieved. The first set of measurements showed that the energy consumption was 1.01 MJ/kg beet, which was 20% higher than intended, but at the same time energy savings were about 30% lower with respect to the values before the reconstruction.

Different authors have investigated hot air drying of sugar beet pulp, but no data on drying kinetics can be found in the literature. The aim of this study was to find suitable model for drying kinetics of sugar beet pulp. Of all models applied to drying curves, the best results were obtained for logarithmic equation. Also it was found that pressing of sugar beet pulp reduces time needed for drying by 10%, without any change in drying kinetics or any significant influence on coefficient of rehydration ratio.

A mathematical model of diafiltration with variable volume is presented in this study. The characteristics of the process were examined, both with constant flux and variable flux. In the case of variable flux, the equations for the flux were taken from the literature, based on different theories. The time dependence of the macro solute concentration, the amount of out-wash liquid, the out-wash degree of the micro solute were studied. The results show that the accomplishment of a high concentration of macro solutes, required more time and out-wash liquid. In order to remove small amounts of micro solutes larger amounts of out-wash liquid must be used. For high degrees of out-washing, the velocity of the process increases and the amount of out-wash liquid decreases. It was observed that the rejection coefficient decreased with macro solute penetration through the membrane causing decrease of the process velocity.

A model with simultaneous ultrafiltration and diafiltration, which includes the rejection coefficients, is presented in this study. Adding a diafiltration solution at a constant, lower rate than the filtrate rate results in a constant decrease of the solution volume in the tank. This enables the simultaneous attainment of the desired macrosolute concentration and microsulute dilution. The proposed model, based on incomplete macrosolute rejection and incomplete mi-crosolute permeation through a membrane, as well as constant permeate flux, is compared to the classical constant volume, diafiltration process. The obtained results show that less diafiltration volume is necessary with this process. Simultaneously, the duration of the process, for higher purification requirements, is shorter in this case.

Flux declines versus time during cross-flow microfiltration of wheat starch suspensions were modeled using fuzzy logic systems under different conditions of transmembrane pressure, flow rate, and suspension concentration. Fuzzy modeling is one of the most efficient methods for empirical modeling, especially for non-linear systems, and does not require any prior knowledge about the process. The influence of the process parameters on the dynamic behavior of the permeate flux was determined by comparing the permeate flux decline versus the volume curves, considering a constant value of the volumetric concentration factor during batch cross-flow filtration. At the transient stages of the filtration process, the permeate flux was shown to be strongly dependent on all process parameters, within the examined range. [ABSTRACT FROM AUTHOR]

Clean technology or clean production is the most important factor for the economic growth of a society and it will play the main role not only in the area of cleaner production, but also in sustainable development. The development of clean technology will be the main factor of the company's strategy in the future. Each company, which wants to reach the competitive position at the market and wants to be environmentally friendly, has to accept the new approach in corporate management and the strategy of new clean technology. The main principles of clean technology are based on the concept of maximum resource and energy productivity and virtually no waste. This approach may be limited by human resources and the level of their environmental knowledge. Companies are committed to the development of the workers' skills, and thus to the improvement of the company for the full implementation of the environmental legislation and clean production concept. Based on this commitment, one of Tempus projects is designed to improve the university-enterprise cooperation in the process of creating sustainable industry in Serbia, Bosnia and Herzegovina and the Former Yugoslav Republic of Macedonia. To achieve this goal, partner universities will create special courses on sustainable industry and thus enhance the lifelong learning process and cooperation between industry and universities in the Western Balkan countries. [ABSTRACT FROM AUTHOR]

Abstract: The Autonomous Province of Vojvodina is an autonomous province in Serbia, containing about 27% of its total population according to the 2002 Census. It is located in the northern part of the country, in the Pannonia plain. The importance of sector of the environment protection becomes even larger and observable, especially with respect of the strategic determination of Government of the AP of Vojvodina, the Republic of Serbia on the association with the European economic area (EEA) and joining with the states – members of the European Union (EU). Restitution of the concept of the cleaner production (CP) significantly helps to companies and the responsible persons (especially in the domain of industry) to harmonize their business activities with law demands concerning the environment protection, as well as to improve their processes and the process sequences. This makes a starting base for the obtaining of the integrated license for the installations that are included in a list of installations that have to obtain an integrated licenses (some 250 installations), on the basis of the Law on the integrated prevention and control of pollution of Vojvodina, the Republic of Serbia, for which the dead point is the year 2015. [Copyright &y& Elsevier]

Abstract: In this study, the policy, market conditions and food security of biomass energy sources are assessed for supplying the future needs of Vojvodina. The Autonomous Province of Vojvodina is an autonomous province in Serbia, containing about 27% of its total population according to the 2002 Census. It is located in the northern part of the country, in the Pannonia plain, in southeastern Europe. Vojvodina is an energy-deficient province. Vojvodina also has a large potential for renewable energy, especially energy from biomass (biodiesel and bio-ethanol). The lack of knowledge about renewable energy technologies by most policy-makers, potential consumers, and energy firm managers has played against renewable energy developments. The environmental impacts of programs that encourage biofuel production, farmland land requirements and the impacts on food production are also discussed, considering the life cycle analysis (LCA) as a tool. It is concluded that the rise in the use of biofuels is inevitable and that international cooperation, regulations and certification mechanisms must be established regarding the use of land, the mitigation of environmental and social impacts caused by biofuel production. It is also mandatory to establish appropriate working conditions and decent remuneration for workers of the biofuels production chain. [Copyright &y& Elsevier]