1,721,011 research outputs found
Mechanical performance of historical wrought iron rods
No full textHistorical masonry buildings are often reinforced with ferrous tie rods. Before the late 18th century, such rods were hot formed by using wrought iron deriving from either the bloomery or the finery process; thereafter, the puddling process was introduced and gradually became prevalent. Several such tie rods are still in service in cultural-heritage buildings; their analysis can shed light on historical production processes and building techniques, and knowledge of their mechanical performance can be valuable for architectural conservation purposes. Four steel tie rods, which were retrieved from a 17th century masonry building in Turin, Italy, and are dated to the late 17th and early 19th centuries, are examined here, by means of chemical and microstructural analyses, tensile tests and fractographic examinations, and both the material fabrication procedure and its mechanical performance are discussed
Influence of iodide ions on corrosion of dual‐phase steel in sulfuric acid solution
No full textPotassium iodide was studied for its corrosion inhibition property on the corrosion of dual‐phase steel in 0.5M sulfuric acid at 25°C by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Scanning electron microscopy was used to characterize the steel surface. The inhibition efficiency increases with the concentration of iodide ions. The thermodynamic parameters Kads and ΔG0ads are calculated and discussed. The probable inhibitive mechanism is proposed from the viewpoint of adsorption theory
Assessing the corrosion resistance of binary Al–Sc alloys in chloride-containing environment
No full textThe corrosion behaviour of binary Al–Sc alloys (Al-0.3Sc and Al-1Sc, wt%) is investigated in de-aerated 0.6 M NaCl solution, performing potentiodynamic polarisation, potentiostatic transients and electrochemical impedance spectroscopy (EIS) measurements complemented with scanning electron microscopy (SEM). In the presence of chloride ions, both Al–Sc alloys experience localised corrosion (pitting). However, increasing Sc alloying addition leads to an increase of the breakdown potential and the extent of passivation domain, indicating improved resistance to initiation of pitting corrosion. Furthermore, EIS measurements performed at the breakdown state evidenced a higher Rct and a lower depression angle value for the Al-1Sc alloy compared to the Al-0.3Sc one, confirming its better localised corrosion behaviour. Spatial distribution and volume fraction of the Al3Sc secondary phase are microstructural features which play a very important role in determining the corrosion resistance of the Al-1Sc alloy
Influenza del tipo di trattamento termico sul comportamento elettrochimico di un acciaio per la lavorazione a freddo
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Identification of the preferential gaze position through elevation of visual fatigue in a selected group of VDU operators. A preliminary study
No full textA selected group of VDU workers were tested in an attempt to achieve objective evidence of visual fatigue and to identify a preferential monitor/gaze position during a particular work setting. Each subject was scored in a two-phase test. The highest mean scores were achieved when the monitor was lowered with respect to the primary/gaze position; the scores obtained with the monitor in primary or upward gaze position were significantly lower (p < 0.001). The downward gaze position should be considered more comfortable for both innervational and anatomical factors, as stated in previous studies of ocular mobility. A reduction of vertical saccades could also play a role in lessening visual fatigue in this gaze position
Electrochemical corrosion behaviour of binary magnesium - Heavy rare earth alloys
No full textThe corrosion properties of magnesium-heavy rare earth (RE) based alloys have been studied. Binary additions of gadolinium (Gd), dysprosium (Dy) and erbium (Er) to pure magnesium were made to a nominal 1 at.%. The corrosion resistance of Mg99Gd1, Mg99Dy1 and Mg99Er1 alloys has been assessed by using open circuit potential measurements, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) carried out in 0.075 M Na2B4O7 + 0.05 M H3BO3 solution, pH = 8.4. Electrochemical results showed that heavy RE alloying additions significantly improves the corrosion behaviour of magnesium. This improvement can be attributed to enhanced barrier properties of the corrosion products layer and additional active corrosion protection originated from the inhibiting action of the lanthanide cations entrapped as oxides/hydroxides in this surface layer
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