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Abstract

In the paper, on the basis of the performed tests, low-cycle fatigue characteristics (LCF) of selected light metal alloys used among others in the automotive and aviation industries were developed. The material for the research consisted of hot-worked rods made of magnesium alloy EN-MAMgAl3Zn1, two-phase titanium alloy Ti6Al4V and aluminium alloy AlCu4MgSi(A). Alloys used in components of means of transport should have satisfactory fatigue, including low-cycle fatigue, characteristics. Low-cycle fatigue tests were performed on an MTS-810 machine at room temperature. Low-cycle fatigue tests were performed for three total strain ranges Δεt = 0.8%, 1.0% and 1.2% with a cycle asymmetry coefficient R = –1. On the basis of the obtained results, characteristics of the fatigue life of materials, cyclic deformation σa = f(N) and cyclic deformation of the tested alloys were developed. The tests showed that titanium alloy Ti6Al4V was characterised by the highest fatigue life Nf, whereas the lowest fatigue life was found in the tests of the aluminium alloy AlCu4MgSi(A).
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Abstract

Reduction of three industrial nickel oxides (Goro, Tokyo and Sinter 75) with a hydrogen bearing gas was revisited in the temperature interval from 523 to 673 K (250 to 400°C). A pronounced incubation period is observed in the temperature interval tested. This period decreases as the reduction temperature increases. Thermogravimetric data of these oxides were fitted using the Avrami-Erofeyev kinetic model. The reduction of these oxides is controlled by a nucleation and growth mechanism of metallic nickel over the oxides structure. Rate kinetic constants were re-evaluated and the activation energy for the reduction of these oxides was re-calculated.
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Abstract

In the design of asphalt mixtures for paving, the choice of components has a remarkable importance,as requirements of quality and durability must be assured in use, guaranteeing adequate standardsof safety and comfort. In this paper, an approach of analysis on the aggregate materials using fractal geometry is proposed. Following an analytical and an experimental approach, it was possible to find a correlation betweencharacteristics of the asphalt concrete (specific gravity and porosity) and the fractal dimension ofthe aggregate mixtures. The studies revealed that this approach allows to draw the optimal fractal dimension and, conse-quently, it can be used to choose an appropriate aggregate gradation for the specific application;once the appropriate initial physical parameters are finalized. This fractal approach could be employed for predicting the porosity of mixed asphalt concretes,given as input the fractal characteristics of the aggregate mixtures of the concrete materials.
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Abstract

Green-geo-engineering with geosynthetic reinforced soil structures is of increasing practice around the world. Poland is among the leading countries with the third biggest geogrid market in Europe. The German EBGEO 2010 Guideline for Soil Reinforcement with Geosynthetics as first European Guideline for Geosynthetics linked to the Eurocode 7, and the new design code for Japanese railway structures under seismic loading are introduced. New research results from the Geotechnical Institute of the RWTH Aachen, Germany, dealing with the soil/reinforcement interaction and new approaches for design codes for the reinforcement of base courses in traffic areas based on lab and field tests in the USA are presented.
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