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Number of results: 4
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Abstract

An attempt has been made to synthesize the aluminium based ex-situ (Al-SiC) and in-situ (Al-TiB2) formed metal matrix composites with varying weight percentage of reinforcement contents such as 4wt.%, 6wt.% and 8wt.%. Synthesized composites were subjected to a cold extrusion process followed by heat treatment according to the ASTM B 918-01 standards. The mechanical properties of in-situ composites were evaluated as per the ASTM guidelines and compared with ex-situ formed composites and base metal properties. Superior properties were noticed in the in-situ formed composites and the mechanical properties such as yield strength, Ultimate tensile strength (UTS) and Hardness for both ex-situ and in-situ composites were found to increase with increasing the reinforcement addition. Cold extruded Al-8 wt.% SiC composite properties such as hardness, yield strength and UTS are 87 RB, 152 MPa, 216 MPa respectively. Whereas, for Al-8 wt.% TiB2 composite, the corresponding properties are 94 RB, 192 MPa, 293 MPa. The morphology of the composites is analysed by Optical and Scanning Electron Microscopic (SEM) whereas presence of reinforcement particles such SiC and TiB2 along with intermetallic phases Mg2Si and Al5FeSi are confirmed by EDX, XRD and Element Mapping analyses.
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Authors and Affiliations

B. Gobalakrishnan
1
C. Rajaravi
2
Gobikrishnan Udhayakumar
3
P.R. Lakshminarayanan
4

  1. CARE College of Engineering, Department of Mechanical Engineering, Trichy-620 009, Tamil Nadu, India
  2. Hindusthan College of Engineering and Technology, Coimbatore – 641 032, Tamilnadu, India
  3. Sona College of Technology, Department of Mechanical Engineering, Salem – 636 005, Tamil Nadu, India
  4. Annamalai University, Department of Manufacturing Engineering, Annamalai Nagar-608 002, Tamil Nadu, India
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Abstract

Post-mining dumps are a common sight in the industrial areas of Silesia (Poland). Despite several reclamation projects, many of them still constitute an unresolved problem. It is not only a matter of unaesthetic view – they often pose a threat to the environment and the people living nearby. Despite revitalization, some dumps are not properly maintained and are at the risk of slope failure. Such places require constant geodetic observation and stability control. In this article, the example of a dump located in the city of Gliwice was used to show the possibilities offered by the use of photogrammetry and unmanned aerial vehicles (UAV) for cyclic checks of the embankment condition. The current state of the dump and the results of interventions after two incidents of slope failure,were observed. The main slopes of the terrain surface and at the selected cross-sections were determined in two flight missions. The obtained geometrical data were used in the further numerical analysis. Finite Element Method model representing one of the escarpment cross-sectionswas built to estimate the factor of safety and determine the main mechanisms responsible for the failure. Elastic-perfectly plastic Coulomb-Mohr model was used to describe the behaviour of the minestone and the ‘ c – tan φ reduction’ – for calculation of the stability. The problem of reliable material properties’ estimation was emphasized. The analysis included the impact of seepage and total head difference on the slope stability. It was concluded that the rainfall intensity had a decisive influence on the instability of the dump.
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Authors and Affiliations

Magdalena Wróblewska
1
ORCID: ORCID
Magdalena Kowalska
1
ORCID: ORCID
Marian Łupieżowiec
1
ORCID: ORCID

  1. Silesian University of Technology, Faculty of Civil Engineering, Department of Geotechnics and Roads, Akademicka 5, 44-100 Gliwice, Poland
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Abstract

The author reflects on the evaluation of the notion of money in history. In many situations coins and banknotes were a proof for the existence of local, independent, political power. People’s attitude toward money was quite an important matter, too; in many situations neither money nor those professionally dealing with money were appreciated socially. Numerous utopian movements disliked money. Communism was one of them. The communist economy was driven — at least in theory — by overwhelming planning rather than by the incentive of money. After the fall of communism a question arised whether all or nearly all public activity should be driven by money or whether some domains of social activity should rather be kept as public domains.

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Authors and Affiliations

Marcin Kula
ORCID: ORCID

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