Bogdan Popović

ICTM pressure transmitter in the feed water system of the thermal power plant

This paper presents implementation of pressure transmitters, developed at Institute of Chemistry, Technology and Metallurgy (ICTM), within the feed water system existing in thermal power plant TENT-A located in Obrenovac, Serbia. For this purpose, high pressure transmitters (up to 400 bar), with standard current output (4-20) mA, digital display for in-situ reading and incorporated HART protocol for remote reading, are used. This type of monitoring enables higher degree of reliability, safety and energy efficiency of the feed water system. In order to optimize the energy efficiency aspect, special attention is focused on accuracy and precision of the measurements.

Structural and microhardness characterization of thin electrodeposited Ni/Cu multilayers on copper substrates

Multilayered composite systems of alternately electrodeposited nanocrystalline Cu and Ni films on cold-rolled microcrystalline copper substrates were fabricated. Highly-densified parallel interfaces which can give rise to high strength of composites are obtained by depositing layers at a very narrow spacing. The mechanical properties of the composite systems were characterized using Vickers microhardness testing with loads ranging from 1.96 N down to 0.049 N. Dependence of microhardness on layer thickness, Ni/Cu layer thickness ratio and total thickness of the film was investigated. The microhardness increased with decreasing the layer thickness down to 30 nm and it is consistent with the Hall-Petch relation. Composite hardness model of Korsunsky was applied to the experimental data in order to determine the composite film hardness. The highest value of all the composite film hardness values was obtained when the ratio of Ni : Cu layer thickness was 4:1.

The importance of remanufacturing in transmitters production

This paper presents a algorithm for the improvement of the manufacturing process developed and tested for small-scale enterprise. The validity of the algorithm can be seen through: defining basic elements, defining environmental factors, the importance of resources, and the analysis of input and output in the manufacturing process. The algorithm incorporates implemented strategies: remanufacturing and 4Rs. The paper analyzed the temperature transmitter at the end of its life circle. Reuse transmitter is realized through: checking, disassembly, replacement parts, cleaning, re-assembling and testing. The work provides an example of how to save energy and materials which appear as large losses in the manufacturing process.

Prevention of convex corner undercutting in fabrication of silicon microcantilevers by wet anisotropic etching

This paper presents microcantilever fabrication on {100} oriented Si substrate using bulk micromachining technique. Detailed characteristics of convex corner compensation design for 〈100〉 oriented beam for two etching solutions: 25 wt. % TMAH and 30 wt. % KOH water solutions at 80 °C are given.

Comparative microhardness analysis of various thin metallic multilayer composite films

Different composite systems of electrodeposited monolayered and multilayered thin metal films of Ni and Cu on cold-rolled copper substrates were made. Thin metal layers were deposited at narrow spacing of 300 nm and 150 nm and high strength of composites was obtained. Microhardness analysis was performed on the systems of ED Ni film (sulphate “Slotonik 20” electrolyte) / ED Cu film (sulphate electrolyte), ED Ni film (sulphamate electrolyte) / ED Cu film (sulphate electrolyte) and ED Ni film (sulphamate electrolyte) / ED Ni film (“Slotonik 20” electrolyte). Characterization of mechanical properties of the composite systems was done using Vickers microhardness testing with loads ranging from 0.049 N to 1.96 N. Dependence of microhardness for different composite systems on microstructure and Ni/Cu and Ni/Ni layer thickness ratio was investigated. Composite hardness model of Korsunsky was applied to the experimental data in order to determine the absolute composite film hardness. The highest value of all the composite film hardness values was obtained for the system of multilayered Ni films from two different electrolytes, and ”Slotonik 20” and sulphamate and with sublayer thickness ratio 1:2, respectively.