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Abstract

The paper presents the theory of constraints (TOC) as a method used to improve results in a complex, multiplants organization. In the article the assumptions of this method has been presented as well as iterative approach concerning how to launch it in practice. Main indicators for organizational effectiveness assessment have also been presented. The maximization of production assets utilization is a key issue for competitive organization in the changing market conditions. An appropriate usage of the theory of constraints enables efficient allocation of financial assets among particular plants within a capital group. An application of a method has been presented based on throughput analyses and its influence to improve financial results of one plant organization and synergy effect in multiplants organization. The theory of constraints can be used in almost every kind of business sectors, among them are metal and foundry industries. It allows to be implemented in production organizations as well as in any other company’s profiles. Everywhere the constraint has been defined there is a chance to achieve an improvement following the presented method. The examples have been taken from the casting plants which use continuous and mold casting technologies. The examples show that TOC approach can be successfully employed as the improvement tool of foundries’ performances.
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Abstract

The investigations were carried out in order to assess the effect of thermophilic fermentation on changes in concentration of seven congeners with codes: 28, 52, 101, 118, 138, 153 and 180 in sewage sludge. The total concentration of PCBs was the highest before the process of thermophilic fermentation. On the tenth day of the process of fermentation it was found that the total concentration of LCB doubled the previous level, whereas in higher chlorinated PCBs this value decreased twice. After the process of thermophilic digestion, all the determined congeners of PCBs were still present. However, their total concentration was reduced by 84% on the fourteenth day of the process. Low concentration of heavy metal ions in the liquid phase of sewage sludge was observed. The metal ions precipitated and remained bound throughout the stabilization process. Metal speciation analysis was performed, and revealed some changes in the chemical forms of the metals during the stabilization process of sludge. The highest increase of zinc, copper, nickel, cadmium, and chromium concentration was observed in the organic-sulfide fraction, whereas the highest increase of lead was found in the residual fraction. Thermophilic methane fermentation did not cause the accumulation of heavy metals in the mobile fractions of sludge.
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Abstract

This work presents the results of a study whose aim was to determine the influence of algal blooms on precipitation of heavy metals. The scope of the study covered culture of a mixed population made up of Scenedesmus and Pseudokirchneriella algae in experimental conditions and initiating a metal biosorption process with the use of culture biomass by administering ions of Zn(II) and Ni(II). The process was controlled by assessing the level of biosorption of metals entered at a one-off basis in the form of Zn(II) and Ni(II) salts or in the form of mixture of both ions, in comparison to the control sample, at different exposure times (2 hours and 24 hours). The presence of metals was determined both in the biomass and in the culture medium. The presented results of the study confirm the effectiveness of Chlorophyta in the process of zinc and nickel biosorption. A phenomenon of competitiveness between the metals was observed when they were administered at the same time.
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