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Number of results: 7
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Abstract

Food additives, especially E numbers, are widely perceived by consumers as artificial and harmful. However, the fact is that they are an essential ingredient in numerous products, many have “natural” origins and none of them pose a risk to health.
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Abstract

The work presents results of the investigations of effect of intensive cooling of alloy AC-AlSi7Mg with alloy additions on microstructure and mechanical properties of the obtained casts. The experimental casts were made in ceramic molds preliminarily heated to 180°C, into which AC-AlSi7Mg with alloy additions was poured. Within implementation of the research, a comparison was made of the microstructure and mechanical properties of the casts obtained in ceramic molds cooled at ambient temperature and the ones intensively cooled in a cooling liquid. Kinetics and dynamics thermal effects recorded by the TDA method were compared. Metallographic tests were performed with the use of optical microscope and strength properties of the obtained casts were examined: UTS, Elongation and HB hardness.
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Abstract

In this paper, the influence of Mo addition on the structure and mechanical properties of the NiCoMnIn alloys have been studied. Series of polycrystalline NiCoMnIn alloys containing from 0 to 5 mas.% of Mo were produced by the arc melting technique. For the alloys containing Mo, two-phase microstructure was observed. Mo-rich precipitates were distributed randomly in the matrix. The relative volume fraction of the precipitates depends on the Mo content. The numbers of the Mo rich precipitates increases with the Mo contents. The structures of the phases were determined by the TEM. The mechanical properties of the alloys are strongly affected by Mo addition contents. Brittleness of the alloys increases with the Mo contents.
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Abstract

Steel and cast-iron products, due to their low price and beneficial properties, are the most widely used among metals; their consumption has become an indicator of the economic development of countries. The characteristics of iron raw materials, in relation to current metallurgical requirements, are presented in the present this article. The globalization of the trade and development of steelmaking technologies have caused significant changes in the quality of raw materials in the last half-century forcing improvements in processing technologies. In many countries, standard concentrates (at least 60% Fe) are almost twice as rich as those processed in the mid-20th century. Methods of quality assessment have been improved and quality standards tightened. The quality requirements for the most important raw materials ‒ iron ores and concentrates, steel scrap, major alloy metals, coking coal, and coke, as well as gas and other energy media ‒ are reviewed in the present paper. Particular attention is paid to the quality testing methodology. The quality of many raw materials is evaluated multi-parametrically: both chemical and physical characteristics are important. Lower-quality parameters in raw materials equate to significantly lower prices obtained by suppliers in the market. The markets for these raw materials are diversified and governed by separate sets of newly introduced rules. Price benchmarks (e.g. for standard Australian metallurgical coal) or indices (for iron concentrates) apply. Some raw materials are quoted within the framework of the commodity market system (certain alloying components and steel scrap). The abandonment of the long-established system of multi-annual contracts has led to wide fluctuations in prices, which have reached a scale similar to that of other metals.
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Abstract

The study was conducted on 26 male, 30 days-old goats, separated from their mothers, divided into two equal groups: I - control and II - experimental, consisting of 13 animals each. All animals were fed with milk replacer, experimental group received additionally 50 g/kg body weight, additive of HMB, for 60 days. The following features were analyzed: body weight, daily increases of body weight, as well as hematological and biochemical blood features. Differences in body weight were found, between experimental and control group, after 60 days of experiment 0.57 kg (p≤0.01). The daily weight gain of experimental animals was higher in comparison with control group. Significant differences were also noted in results of hematological and biochemical blood parameters. Experimental animals showed a higher level of red blood cells as well as number of lymphocytes in comparison with the control group, (p≤0.01).Significant changes were also observed in the level of triglycerides, inorganic phosphorus and protein between both groups. The acid-base balance parameters and ionogram, showed a higher pH level (p≤0.05) HCO – act., HCO – std., BE, ctCO , O sat, K+, Cl– (p≤0.01), while the anion gap (AG) and Na+ were significantly lower in control group (p≤0.01).
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Abstract

The study presents the results of the investigations of the effect of Cu, Ni, Cr, V, Mo and W alloy additions on the microstructure and mechanical properties of the AlSi7Mg0.3 alloy. The examinations were performed within a project the aim of which is to elaborate an experimental and industrial technology of producing elements of machines and devices complex in their construction, made of aluminium alloys by the method of precision investment casting. It was demonstrated that a proper combination of alloy additions causes the crystallization of complex intermetallic phases in the silumin, shortens the SDAS and improves the strength properties: Rm, Rp0.2,HB hardness. Elevating these properties reduces At, which, in consequence, lowers the quality index Q of the alloy of the obtained casts. Experimental casts were made in ceramic moulds preliminarily heated to 160 °C, into which the AlSi7Mg0.3 alloy with the additions was cast, followed by its cooling at ambient temperature. With the purpose of increasing the value of the quality index Q, it is recommended that the process of alloy cooling in the ceramic mould be intensified and/or a thermal treatment of the casts be performed (ageing)(T6).
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Abstract

Transverse effective thermal conductivity of the random unidirectional fibre-reinforced composite was studied. The geometry was circular with random patterns formed using random sequential addition method. Composite geometries for different volume fraction and fibre radii were generated and their effective thermal conductivities (ETC) were calculated. Influence of fibre-matrix conductivity ratio on composite ETC was investigated for high and low values. Patterns were described by a set of coordination numbers (CN) and correlations between ETC and CN were constructed. The correlations were compared with available formulae presented in literature. Additionally, symmetry of the conductivity tensor for the studied geometries of fibres was analysed.
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