By corrosion effect, the surface of the metal becomes so rough that there are reduction in metal strength as a consequence of nicking. It should be added that the continuing effects of corrosion produces deep and sharp notches in the metal. It causes tiny cracks that allow further penetration of corrosion. As results of this activities, the dynamic hardness by simultaneously highly corrosion effect substantially decreases so that it may lead to fatigue failure, as shown in this paper. It is also not possible to establish any qualitative or quantitative legality between dynamic strength and corrosion effects. This hold for the effect of corrosion on unloaded metal element. This must be tested in all chance.

This paper, on the example of a typical loaded welded assembly, made optimization of its dimensions in terms of the cost of welding. In such an elaboration the mathematical optimization model with limitation functions has also been presented and it should be taken into account in the process of designing by the technologist and designer. To solve the presented problem the method of geometric programming was proposed that has in detail been elaborated in the paper in the form of an algorithm suitable for the application. In this way the optimization or primary task was reduced to a dual task through a proper function, which is much easier to solve. The method has been illustrated on a practical computational example with a different number of limitation functions. It is shown that in case of a lower degree of complexity the solution can be reached by maximizing the corresponding dual function by means of mathematical analysis. In case of a higher degree of complexity, it is necessary to use some of the methods of non-linear programming. In this case the solution of the problem is simplified due to the minimization of a linear equation.

In the last decade of the 20 th century, the problems of poverty and social exclusion became topical on a European scale. Bearing in mind Serbia’s European perspective, social policy has been gaining in significance. Serbia is a transition country lagging behind other ex-socialist countries, something that is evident in almost all socio-economic, political and societal spheres. In that context, Serbia has no consistent and uniform national strategy of social development, and this ranks it at the very top of the European tree where poverty and social exclusion are concerned. Neither factor is an individual’s choice, but rather emerge as the consequence of different social and cultural circumstances. Such multi-dimensional problems imply a responsibility for society as a whole and modern, relevant and sustainable solutions are a necessity. Serbia must diminish the gap to Europe in the field of economic-social indicators, which is only possible through economic, social and societal advancement. Here, both co-operation and co-ordination with European partners will be required.

The subject of the research is influence of sulfuric acid on morphology of electrochemically obtained copper powder during galvanostatic electrolysis mode. In this paper electrodeposition of copper powder from sulphate electrolyte was carried out. Electrolytes with three different concentrations of Cu2+ (7 g/dm3, 18 g/dm3 and 33 g/dm3) were used, each in combination with three different concentrations of H2SO4 (100 g/dm3, 150 g/dm3 and 200 g/dm3), so that copper powder was deposited from nine electrolytes. Copper wire with surface area of 1cm2 was used as cathode, and copper anode in the form of metal sheet was pressed against the wall of electrochemical cell that had volume of 500 cm³. Experiments were carried out at room temperature, and electrolyte stirring was performed using a magnetic stirrer. Copper powder was deposited galvanostatically at current densities of j = 1500 A/m2, j=2000 A/m2 and j=2500 A/m2. Produced copper powder was removed from cathode every three minutes. All the characteristics of powder depend on the size and shape (morphology) of particles and they are mutually correlated. Research of morphology and size of particle was carried out using scanning electron microscopy (SEM). Increase of H2SO4 concentration causes increase in branching of copper powder. It was concluded that the size of copper powder grains reduces with the increase in concentration of H2SO4.

This paper examines industrialization and structural change induced thereof, which are the main drivers and bearers of economic development. The author observes that the industry of the Republic of Serbia is devastated due to sudden and premature tertiarization as well as inadequate reforms. The current structures of both the economy and the industry do not have a sufficient capacity to ensure sustainable economic development; hence, the aim of the research presented in this paper is to emphasize the importance of reindustrialization and the implementation of structural changes in the Republic of Serbia. The paper starts from the premise that industry is the main driver and the bearer of economic growth and development. Therefore, it is necessary for the Republic of Serbia to turn to reindustrialization and implement structural changes in this sector given the fact that the levels of the development and competitiveness of the industry are correlated to the intensity of industrialization. The research findings indicate that developed industrial countries are characterized by more effective structural changes and more propulsive production that creates higher value-added products. This reflects not only at the level of the industrial development but also at the level of the competitiveness, volume and quality of exports.

The most promising biofuels are bioethanol, biodiesel, pure pl ant oil, and biomethane. Many biofuels generate large benefits when compared to fossil fuels. The use of bioethanol will largely depend on the potentialof available and continuously re -growing biomass, the feedstock sources. Bioethanol produced from renewable feedstock has great potential to reduce greenhouse gasses emissions related to the combustion of fossil fuels. It has chemical and physical properties that are close to fuels from fossil fuels and can be used to exchange petrol in existing engines. Generally bioethanol is expected to have large socio-economic impacts, especially for local actors. Bioethanol production opens new market opportunities for agricultural products and thus new income options for farmers. In the future agriculture will not onl y play a role in food production, but also in energy provision.