Trends in aircraft noise annoyance: the role of study and sample characteristics

Recently, it has been suggested that the annoyance of residents at a given aircraft noise exposure level increases over the years. The objective of the present study was to verify the hypothesized trend and to identify its possible causes. To this end, the large database used to establish earlier exposure-response relationships on aircraft noise was updated with original data from several recent surveys, yielding a database with data from 34 separate airports. Multilevel grouped regression was used to determine the annoyance response per airport, after which meta-regression was used to investigate whether study characteristics could explain the heterogeneity in annoyance response between airports. A significant increase over the years was observed in annoyance at a given level of aircraft noise exposure. Furthermore, the type of annoyance scale, the type of contact, and the response percentage were found to be sources of heterogeneity. Of these, only the scale factor could statistically account for the trend, although other findings rule it out as a satisfactory explanation. No evidence was found for increased self-reported noise sensitivity. The results are of importance to the applicability of current exposure-annoyance relationships for aircraft noise and provide a basis for decisions on whether these need to be updated.     

Odd random phase multisine EIS as a detection method for the onset of corrosion of coated steel

In this work, odd random phase multisine Electrochemical Impedance Spectroscopy (ORP-EIS) was used as a detection method for the onset of corrosion of coated steel. The possibility to use ORP-EIS as a rapid-screening test for corrosion was investigated. It is concluded that the detection of a non-linear behavior combined with a non-stationary behavior during the onset of corrosion can be used as a criterion in a rapid-screening test for corrosion of coated steel.     

The combination of surface enhanced Raman spectroscopy and an ionic liquid as a model system to study the adhesion interface between sulfur and brass

The adhesion of steel cord to rubber is very important for the quality of reinforced rubber products, e.g. tyres. Therefore, steel cord is often plated with brass, which will lead to Cu_xS bonds after reaction with sulfur compounds in the rubber. A unique in‐situ analytical method has been developed to investigate the sulfur–brass interface: the sulfuring process has been simulated via a heating process in a water‐free transparent ionic liquid with added sulfur and the reaction at the brass‐coated steel cord has been monitored in real time with Raman spectroscopy. The grown Cu_xS film seems to be similar to the layers at the steel cord interface in real rubber materials. The model system can also be used to perform electrochemical measurements at the same time. The thickness of the Cu_xS layer has been estimated from the measured current during a cathodic stripping process. Copyright © 2013 John Wiley & Sons, Ltd.     

Modeling of mass and charge transfer in an inverted rotating disk electrode (IRDE) reactor

In this work, the validation of a newly constructed inverted rotating disk electrode (IRDE) reactor is reported. Compared to the rotating disk electrode (RDE) reactor, the working electrode is changed in position from the top to the bottom of the electrochemical cell. The IRDE reactor is designed to facilitate the actual study of gas evolution reactions. It is studied whether the first-order analytical expression for the velocity field in an RDE reactor is also acceptable for an IRDE configuration. To that purpose, the kinetic parameters of the well-known ferri/ferro cyanide redox system are determined in both configurations and compared. This is done qualitatively by comparing the polarization curves obtained in the inverted and the conventional RDE configuration. Additionally, a statistically founded fitting algorithm is used to quantitatively determine the model parameters of the oxidation and reduction reaction. Not only the diffusion coefficients of Fe²⁺ and Fe³⁺ are calculated, but also the rate constants (k_ox and k_red) and the transfer coefficients (α_ox and α_red) are quantified and compared together with their respective standard deviation. It is found that the parameters of mass and charge transfer in both configurations agree well. So it is concluded that the same analytical equations of mass and charge transfer can be used in both the RDE and the IRDE reactor.