The technology transfer of non-ferrous alloys casting during the middle age

The article reports on the findings from the metallographic analysis of 13th c. archaeological objects from Chełm (eastern Poland). The group submitted for analysis includes jeweller’s dies used in the production of women’s ceremonial ornaments, crucibles and bronze ornaments. The Mongol invasion of 13th c. had caused craftsmen from central areas of East Europe to flee and seek shelter in the western parts of Rus. It may be safe to interpret the finds from Chełm as the remains of a jeweller’s workshop, the site of casting and working copper alloys and silver. The analysis of the technology used in casting copper alloys and silver in the jeweller’s workshop were made using optical microscopy, X-ray spectroscopy and X-ray radiography

Copper alloys in investment casting technology

This paper presents research results in the field of casting technology of copper and copper alloys using the investment casting technology, both from historical as well as modern technology perspective. The analysis of exemplary elements of the old casting moulds is included, as well as the Bronze Age casts. The chemical content of various copper alloys was determined and the application of lost wax method was confirmed in the Bronze Age workshop. At present, investment casting method is used for manufacturing high-quality casts, especially products for power engineering that is why it demands respecting very rigorous technological requirements. The casts were characterised based on microstructure research, chemical composition and conductivity in relation to oxygen content

A functional variant in the Stearoyl-CoA desaturase gene promoter enhances fatty acid desaturation in pork

There is growing public concern about reducing saturated fat intake. Stearoyl-CoA desaturase (SCD) is the lipogenic enzyme responsible for the biosynthesis of oleic acid (18:1) by desaturating stearic acid (18:0). Here we describe a total of 18 mutations in the promoter and 3′ non-coding region of the pig SCD gene and provide evidence that allele T at AY487830:g.2228T>C in the promoter region enhances fat desaturation (the ratio 18:1/18:0 in muscle increases from 3.78 to 4.43 in opposite homozygotes) without affecting fat content (18:0+18:1, intramuscular fat content, and backfat thickness). No mutations that could affect the functionality of the protein were found in the coding region. First, we proved in a purebred Duroc line that the C-T-A haplotype of the 3 single nucleotide polymorphisms (SNPs) (g.2108C>T; g.2228T>C; g.2281A>G) of the promoter region was additively associated to enhanced 18:1/18:0 both in muscle and subcutaneous fat, but not in liver. We show that this association was consistent over a 10-year period of overlapping generations and, in line with these results, that the C-T-A haplotype displayed greater SCD mRNA expression in muscle. The effect of this haplotype was validated both internally, by comparing opposite homozygote siblings, and externally, by using experimental Duroc-based crossbreds. Second, the g.2281A>G and the g.2108C>T SNPs were excluded as causative mutations using new and previously published data, restricting the causality to g.2228T>C SNP, the last source of genetic variation within the haplotype. This mutation is positioned in the core sequence of several putative transcription factor binding sites, so that there are several plausible mechanisms by which allele T enhances 18:1/18:0 and, consequently, the proportion of monounsaturated to saturated fat.This research was supported by grants from the Spanish Ministry of Science and Innovation (AGL2009-09779 and AGL2012-33529). RRF is recipient of a PhD scholarship from the Spanish Ministry of Science and Innovation (BES-2010-034607). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of manuscript

Effect of concrete substrate texture on the adhesion properties of PCC repair mortar

peer reviewedThe study of adhesion of repair materials on concrete structures implies a good knowledge of the influence of concrete surface characteristics. A large research project has been realized with regards to the influence of concrete substrate strength and preparation technique efficiency. Three types of concretes and four types of surface preparation have been combined in order to obtain twelve different concrete slabs. They have been characterized according different destructive and non destructive techniques: Schmidt hammer, compressive strength, superficial cohesion (pull-off tests), Impact Echo measurements and cracking quantification (microscopical observations). Finally, a polymer cement concrete mortar has been applied and adhesion has been evaluated by means of pull-off and laboratory tensile tests. The relationships between parameters describing surface quality (roughness, cracking), adhesion strength and stress wave propagation have been analysed

Geometrical properties of polymer films produced in blown molding extrusion process

Właściwości folii wytwarzanej metodą wytłaczania z rozdmuchiwaniem można ocenić na podstawie stopnia rozciągania folii w kierunku poprzecznym, stopnia rozciągania w kierunku wzdłużnym oraz parametrów geometrycznych, to jest grubości i szerokości folii. Właściwości te zależą w dużej mierze od warunków technologicznych procesu, geometrii oraz konstrukcji głowicy wytłaczarskiej, jak również rodzaju tworzywa. W pracy przedstawiono charakterystykę procesu wytłaczania z rozdmuchiwaniem folii jednowarstwowej przy zastosowaniu trzech rodzajów tworzyw poliolefinowych. Zaprezentowano badania wpływu zmiany warunków technologicznych procesu przetwórstwa na parametry charakteryzujące rozciąganie rozdmuchiwanej folii oraz jej właściwości geometryczne.Properties of the films produced by extrusion blow molding can be evaluated by the degree of stretching the film in the cross direction and stretch ratio in the longitudinal direction and geometric parameters, i.e. the thickness and width of the film. These properties depend on the conditions of the technological process, geometry and construction of extrusion head as well as the type of polymer. Process of extrusion blow-molding single-layer films using three types of polyolefins was described. Measurements and studies of the impact of changes in the conditions of technological process of processing parameters characterizing the stretch blown film and geometrical characteristics of the resulting single-layer films were used