Energetic analysis of hard facing and weld cladding of an air powered drop hammer damaged ram

This paper studies problems of hard facing of damaged and initially cracked mechanical engineering heavy parts of complex geometry such as large rams of air powered drop hammers. During long-term exploitation, these parts are subjected to thermal fatigue due to cyclic temperature changes and variable impact compression. Taking into consideration high ram costs and difficulties to purchase ram, the necessity of its reparation becomes obvious. The choices of the most suitable technologies of hard facing and welding of an initially cracked ram are also studied here. Besides the techno-economic analysis, an energetic analysis is performed as an additional criterion in assessment of the proposed technology

Pumpkin pulp extracts from a Serbian Cucurbita maxima Breeding Collection: Phenol profile and in vitro bioactivity

Methanolic pulp extracts from the four selected Serbian accessions of Cucurbita maxima were evaluated for phenol profile cytotoxic effects and antimicrobial activity. The results revealed that quinic acid and amentoflavone were the most abundant phenols. The extracts increased the viability of HTR-8 SV/Neo, JEG-3, JAR cells, with the most pronounced increase in the treatment with MAX 113 extract. Furthermore, in HeLa cells, the extracts showed a modest cytotoxic effect. The antimicrobial effects evaluation showed that out of four pumpkin extracts, MAX 117 could moderately suppress the growth of Staphylococcus aureus and Staphylococcus epidermidis (MIC=1000 µg/mL). The observed biological effects indicate the potential medicinal properties of these pumpkin extracts and contribute to the varietal selection of the most suitable accessions in national breeding programs as candidates for improving human health

Characterization of potassium salts of 12-tungstophosphoric acid

Potassium salts of 12-tungstophosphoric acid with varying amounts of cation, KxH3 - xPW12O40(x = 1, 2, 3) have been prepared and their characteristics investigated by thermal analyses. FT-IR and micro-Raman spectroscopy and SEM-EDS analysis. It was found that the number of replaced protons by potassium ions in the 12-tungstophosphoric acid structure has influence on the presence of different protonic species, their dynamic equilibrium and on the conductivity of salts. The results reported in this study have been applied to improve the structural model of insoluble acidic salts. It is shown that an acidic potassium salt presents a mixture of neutral salt and unreacted acid. The nature of this mixture depends on the number of replaced protons-oxonium ions by cations. Preliminary measurements with synthesized compounds as solid electrolytes in fuel cells have been done, too. (C) 2010 Elsevier Ltd. All rights reserved