Safety risk management in Bosnian-Herzegovinian underground coal mines is not based on a systematic approach and standardized risk management methods. Mostly there is a traditional approach present, i.e. reaction to incidents/accidents that happen. This paper aims to point out the need for proactive approach introduction with an emphasis on importance of ventilation systems failure mechanism simulation analysis in planning of people and property defense and rescue in crisis situations. Based on ventilation parameters measuring results for a given research site (brown coal mine), a model was developed on which a simulation analysis was performed for three characteristic ventilation failure cases: spontaneous oxidation at the longwall exit, collapse at the entrance to the longwall and methane outburst - preparation of a new excavation field. VnetPC and CFD “Fluent” software packages were used to simulate mine ventilation. Keywords: risk management, brown coal mine, safety, ventilation system, longwall, simulation analysis, VnetPC, Fluent.

Brown coal mining conducted at greater depths, characterised with severe mining-geological conditions often results in deviation from the applied mining methods. Experiences gained in mechanised longwall mining of roof plate in deeper parts of Raspotočje mine, using method of roof caving without safety pillars left behind the working panels indicates to shortcomings of the applying mining method. Frequent occurences of spontaneous mine fires, of hazardous gasses well above the limit values, and constant exposure to rock bursts of various in- tensity resulted in application of three longwall face ventilation regimes: conventional „U“ ventilation system, ventilation with gas channel and middle hallway, and separate ventilation of the upper part of the longwall face. This paper presents experience based information gained in a five years period of mining, analysed using one- factor and two factor regression analyses applied to a number of technical-technological parameters (ventilation, mining system, etc) influencing occurences of spontaneous mine fires and increased gas release in various ventilation regimes at longwall face aimed to give basic guidelines for minimisation and elimination of certain hazards. Keywords: ventilation regime, spontaneous fires, gas release, mechanised longwall.

The term transport chain includes the sum of all flows in which the transported goods are in motion, starting from the suppliers of raw materials, through intermediaries-wholesalers and retailers, all the way to the final consumers. The transport chain also includes numerous services that also contribute to increasing the value of the product. What will be the concrete structure of the transport chain, first of all, depends on the characteristics of the product itself, which is required by the final consumer, and which must be offered by the manufacturer. At the same time, the demands of consumers are based on the characteristics of their way of life and lifestyle, including the demands imposed by religious beliefs. These are specific requirements that, for example, are imposed on the Islamic faith through Sharia law. It strictly prescribes what is permissible for Islamic believers (permitted goods, services or behaviors) and is called halal. When we consider the Halal standard and its application in logistics, it means that all members of the supply chain in the Halal product system must comply with Sharia law. It specifically imposes the need for halal certification; specific hygienic and sanitary premises. At the same time, the procedures must be controlled by specially qualified persons and organizations, which are accepted by Islam.

Abstract Acrylamide (AA) is a well-known industrial monomer with carcinogenic, mutagenic, neurotoxic and endocrine disruptive effects on living organisms. AA has been the subject of renewed interest owing to its presence in various food products. We investigated the potential adverse effects of oral AA treatment on the endocrine pancreas of juvenile rats using histochemical, immunohistochemical, stereological and biochemical methods. Thirty juvenile male Wistar rats were divided into one control and two AA treatment groups: one treated with 25 mg/kg AA and the other treated with 50 mg/kg AA for 21 days. We found a significant decrease in β-cell mass. The significant decrease in β-cell optical density and unchanged blood glucose levels indicate that normoglycemia in AA treated rats may result from intensive exocytosis of insulin-containing secretory granules. By contrast with β-cells, we observed increased α-cell mass. The slight increase in α-cell cytoplasmic volume suggests retention of glucagon in α-cells, which is consistent with the significant increase in α-cell optical density for AA treated animals. The number of islets of Langerhans did not change significantly in AA treated groups. Our findings suggest that AA treatment causes decreased β-cell mass and moderate α-cell mass increase in the islets of Langerhans of juvenile male Wistar rats.

In this paper, a numerical study of fluid flow through a pair of corrugated plates was carried out. The aim of the study was to observe and understand the behaviour of the flow and vortex formation through channels where the fluid is subjected to a periodic increase and decrease in the crosssectionarea. The simulations were done in two dimensional space. A wide range of Reynolds numbers were used for each plate. The Reynolds number used was a function of the average plate spacing (Havg) and the laminar flow velocity. Reynolds numbers used were in the range between 200 and 1000.

The Zero emissions concept envisages all industrial inputs being used in final products or converted into value-added inputs for other industries or processes. In this way, industries are reorganized into clusters such that each industry's wastes / by-products are fully matched with the input requirements of another industry, and the integrated whole produces no waste of any kind. This technique is based on the well-established economic analysis tool known as the input/output approach. In the framework of the zero emission concept capture of CO2 plays an important role. CO2 can be captured and permanently stored, or it can be re-used. Carbon sequestration is a two-step process where the capture of CO2 from a gas stream is followed by its permanent storage. The capture step contributes 75% to the overall carbon sequestration process cost. For this reason, the scientific community has paid a great attention to the development of new processes for CO2 capture. Currently, there is a wide range of technologies to separate CO2 from gas streams. They are based on different physical and chemical processes including absorption, adsorption, cryogenics and membrane technology. The choice of a suitable technology depends on the characteristics of the flue gas stream and, as a consequence, on the power plant technology. As an alternative to conventional process es for CO2 separation and capture, membrane technology shows great potentiality for CO2 capture owing to its easy applicability, efficiency, flexibility, ability to maintain high CO2 pressure and to perform separations at low energy penalties. CO2-selective membranes allow separation of CO2 from different gas streams, such as: flue gas (post-combustion system), natural gas (natural gas processing) and hydrogen (pre-combustion systems) or oxygen from nitrogen (in an oxyfuel combustion system). In the framework of zero emission concept, this paper gives an overview and analysis of the types of membranes used and membrane technology application in CO2 capture from the point of cost and energy consumption.

In order to obtain a better heat transfer, it is important to enhance fluid mixing in heat exchangers. Since there are negative effects when heat exchangers are operating in turbulent regime (like significant pressure drop, increased size of the pump) it is necessary to apply the techniques which would provide better fluid mixing when heat exchangers are operating in laminar regime. Investigations have shown that use of sinusoidal instead of flat plates results in this effect. This study is a result of two dimensional simulation of fluid flow between two parallel sinusoidal plates. Simulation was done with the use of modified Openlb code, based on lattice Boltzmann method. Reynolds number was varied from 200 to 1000, and space between the plates was varied from 3cm to 5 cm. Results showed that sinusoidal plates enhance fluid mixing, especially with greater values of Re and smaller space between the plates, which is in agreement with previous investigations.

This paper is concerned with numerical study of the two-sided lid-driven fluid flow in a staggered cavity. The ANSYS FLUENT commercial software was used for the simulation, In one of the simulated cases the lids are moving in opposite directions (antiparallel motion) and in the other they move in the same direction (parallel motion). Calculation results for various Re numbers are presented in the form of flow patterns and velocity profiles along the central lines of the cavity. The results are compared with the existing data from the literature. In general, a good agreement is found, especially in the antiparallel motion, while in the parallel motion the same flow pattern is found, but the velocity profiles are slightly different. [Projekat Ministarstva nauke Republike Srbije, br. 46010]

This paper is concerned with numerical study of fluid flow through a pair of corrugated platest. The aim was to observe and understand the behavior of the flow and vortex formation through channels where the fluid is subjected to a periodic increase and decrease in cross-section area. The plates modeled for the study had sinusoidal profiles. A pair of plates with 180 o phase shift was simulated in two-dimensional spaces. The Reynolds number was a function of the average plate spacing (Havg) and the laminar flow velocity and it was in the range between 200 and 1000.

Membrane process efficiency in the dairy industry is impaired by the formation of deposits during filtration processes. This work describes cleaning procedures for ceramic tubular membrane (50 nm) fouled with whey proteins. Also, mathematical modelling was performed to obtain models which allow deeper insight into the mechanisms involved during cleaning procedures. The caustic solutions (0.2%w/w, 0.4%w/w and 1.0%w/w NaOH) and the mixture of two commercial detergents (0.8%w/w P3-ultrasil 69+0.5% w/w P3-ultrasil 67 and 1.2% P3-ultrasil 69+0.75 P3-ultrasil 67) were used as chemical cleaning agents. The results showed that the best flux recovery was achieved with 0.4%w/w NaOH solution. After analyzing the experimental data, five parameter and six parameter kinetic models were suggested for alkali and detergent cleaning, respectively. The changes of total and specific resistances, as well as the change of the effective pore diameter and deposit thickness during cleaning are estimated by applying these models.

Bojana B. Prodanic, Aleksandar I. Jokic, Jelena Đ. Markovic and Zoltan Z. Zavargo 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“ - Pecinci 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.

The transport of gaseous components through porous media could be described according to the well-known Fick model and its modifications. It is also known that Fick’s law is not suitable for predicting the fluxes in multicomponent gas mixtures, excluding binary mixtures. This model is still frequently used in chemical engineering because of its simplicity. Unfortunately, besides the Fick’s model there is no generally accepted model for mass transport through porous media (membranes, catalysts etc.). Numerous studies on transport through porous media reveal that Dusty Gas Model (DGM) is superior in its ability to predict fluxes in multicomponent mixtures. Its wider application is limited by more complicated calculation procedures comparing to Fick’s model. It should be noted that there were efforts to simplify DGM in order to obtain satisfactory accurate results. In this paper linearized DGM, as the simplest form of DGM, is tested under conditions of zero system pressure drop, small pressure drop, and different temperatures. Published experimental data are used in testing the accuracy of the linearized procedure. It is shown that this simplified procedure is accurate enough compared to the standard more complicated calculations.