The Hubble Servicing Mission Controversy: Is the Risk of a Manned Mission Reasonable?

The National Academy of Sciences Committee recommended that NASA abandon a robotic mission to repair the Hubble Space Telescope and fly a manned mission to repair it instead. Is their assessment to recommend a manned mission sound? Does it meet the criteria of the Columbia Accident Investigation Board

Study of calcium phosphate (DCPD) electrodeposition process on a Mg-3Al-1Zn magnesium alloy surface

Evaluation of calcium phosphating process realized on Mg-3Al-1Zn alloy surface after grinding was investigated by electrochemical tests supported by photodocumentation. The electrodeposition treatment was performed by electrochemical method in water solution of Ca(NO3)2.4H2O, (NH4)2HPO4 and H2O2. The formation of calcium phosphate was divided into several stages and described using light microscopy. The progress in corrosion protection of created calcium phosphate layer in 0.9% NaCl after particular electrodeposition steps was evaluated by electrochemical impedance spectroscopy. The results in the form of Nyquist plots were analyzed using equivalent circuits

Study of calcium phosphate (DCPD) electrodeposition process on a Mg-3Al-1Zn magnesium alloy surface

Evaluation of calcium phosphating process realized on Mg-3Al-1Zn alloy surface after grinding was investigated by electrochemical tests supported by photodocumentation. The electrodeposition treatment was performed by electrochemical method in water solution of Ca(NO3)2.4H2O, (NH4)2HPO4 and H2O2. The formation of calcium phosphate was divided into several stages and described using light microscopy. The progress in corrosion protection of created calcium phosphate layer in 0.9% NaCl after particular electrodeposition steps was evaluated by electrochemical impedance spectroscopy. The results in the form of Nyquist plots were analyzed using equivalent circuits

Corrosion resistance of AZ31 magnesium alloy influenced by conventional cutting fluid

This paper deals with the evaluation of cutting fluid impact on corrosion resistance of AZ31 magnesium alloy in aggressive environment containing chloride ions supported by photo documentation. Ground samples were immersed in the standard commercial cutting fluid for 5 minutes to simulate conditions during machining process at the temperature of 22 ± 2 °C and subsequently cleaned and immersed in 0.1M NaCl solution at the temperature of 22 ± 2°C in order to measure electrochemical corrosion characteristics. Cyclic potentiodynamic polarization (CPP) tests were chosen as a testing method. The measured CPP curves of immersed samples and ground samples were analysed by Tafel extrapolation method. The values of obtained electrochemical characteristics show that the chosen cutting fluid has negative effect on corrosion resistance of AZ31 magnesium alloy in sodium chloride solution.

Influence of mictrostructure features on the corrosion behaviourof AZ91 alloy in chloride media

The influence of the microstructure of as-cast AZ91 magnesium alloy, which applied to solution annealing treatment and ageing treatment respectively, was evaluated in terms of its corrosion behaviour in 0.1 M NaCl solution at room temperature. The corrosion process was monitored by electrochemical impedance spectroscopy (EIS) and the surface was characterized by scanning Kelvin probe force microscopy (SKPFM). The extent of corrosion damage was dependent on the microstructure. Surface potential maps indicated that, the surface potential of α-matrix is more positive than surface potential of β phase

The Corrosion Properties of S355J2 Steel Welded Joint in Chlorides Environment

Nowadays are steels the most used structural material for creation of constructions in different types of industry for lot of applications but suffer from unsatisfactory corrosion resistance in the presence of aggressive chlorides. Steel S355J2 represents common type steel for constructions. Very important property of S355J2 steel is weldability. S355J2 steel was welded by submerged arc welding (SAW) method. Corrosion resistance of welded joint was evaluated by electrochemical methods - linear polarization (LP) and electrochemical impedance spectroscopy (EIS). Results from electrochemical tests are general electrochemical characteristics - ECorr, iCorr, vCorr and RP. Environments for testing were solutions with different concentration of chlorides (0.01M, 0.1M and 1M NaCl solution). Difference of corrosion resistance between base material and weld metal is app. 14.5 %. This difference is preserved in all concentrations of tested environments. The highest corrosion resistance was reached by base material in 0.01M NaCl and the lowest corrosion resistance was reached by weld metal in 1M NaCl

Preparing Evaluation Set for Complex Problems of Recognition and Disambiguation of Named Entities through Crowdsourcing

Práca sa zaoberá prípravou vyhodnocovacej sady pre problémy rozpoznávania a zjednoznačňovania pomenovaných entít. Vyhodnocovacia sada je výsledkom automatizovaného spracovania a crowdsourcingu. Vyhodnocovacia sada môže byť použitá na testovanie pokročilých prípadov v rozpoznávaní a zjednoznačňovaní pomenovaných entít.This Master's Thesis prepares Evaluation Set for Problems of Recognition and Disambiguation of Named Entities. Evaluation Set is created using Automatization and Crowdsourcing. Evaluation Set can be used in testing Edge Cases in Recognition and Disambiguation of Named Entities.