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The quality of some medicinal plants and their water extracts from South East Serbia is determined on the basis of metal content using atomic absorption spectrometry. The two methods were used for the preparation of water extracts, to examine the impact of the preparation on the content of metals in them. Content of investigated metals in both water extracts is markedly lower then in medicinal plants, but were higher in water extract prepared by method (I), with exception of lead content. The coefficients of extraction for the observed metal can be represented in the following order: Zn > Mn > Pb > Cu > Fe. Correlation coefficients between the metal concentration in the extract and total metal content in plant material vary in the range from 0.6369 to 0.9956. This indicates need the plants to be collected and grown in the unpolluted area and to examine the metal content. The content of heavy metals in the investigated medicinal plants and their water extracts is below the maximum allowable values, so they are safe to use

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Abstract. The heat produced in metal cutting process has negative influence on the cutting tool and the machined part in many aspects. This paper deals with measurement of cutting temperature during single-point dry machining of the AISI 4140 steel, using an infrared camera. Various combinations of cutting parameters, i.e. cutting speed, feed rate and depth of cut lead to different values of the measured cutting temperature. Analysis of the measured data should explain the trends in temperature changes depending on changes in the cutting regimes. Furthermore, the temperature data is modelled using response surface methodology and fuzzy logic. The models obtained should determine the influence of cutting regimes on cutting temperature. The main objective is the reduction of cutting temperature, i.e. enabling metal cutting process in optimum conditions. Key words: machining, cutting temperature, infrared thermography, response surface methodology, fuzzy logic.Application of response surface methodology and fuzzy logic based system for determining metal cutting temperature Total amount of heat produced in metal cutting process can be calculated as a sum of heat produced by the three mentioned sources:where: Q -total amount of generated heat, Q S 1 -amount of heat generated by heat source S 1 , Q S 2 -amount of heat generated by heat source S 2 , Q S 3 -amount of heat generated by heat source S 3.The heat balance during metal cutting process can be expressed as follows:where: Q 1 -amount of heat carried away in the chips, Q 2 -amount of heat remaining in the cutting tool, Q 3 -amount of heat passing into the work-piece, Q 4 -amount of heat radiated to the surrounding air.

Aluminum is a metal that is being increasingly used in the packaging