A cellular model for the Mössbauer isomer shift of 99Ru, 193Ir, 195Pt and 197Au in transition metal alloys

It is demonstrated that the isomer shift of Mössbauer nuclei in transition metal alloys can be quantitatively described in terms of an atomic cell model. The isomer shift ΔE, relative to the pure metal as a reference, is derived from a change in boundary conditions for the atomic cell; $\text{ΔE = PΔφ}{}^1\text{+ QΔn}{}_{\mathrm{ws}}$, where ø¹ is the electronegativity parameter, n_ws the cell boundary electron density and P and Q are constants for a given Mössbauer nucleus. For solid solutions there is in addition a relatively small size mismatch term.     

On the sign of the anomalous hall effect in ferromagnetic alloys

Low temperature experimental data on the anomalous Hall resistivity in some binary Ni- and Fe-based alloys are analysed in terms of contributions depending linearly and quadratically on the impurity concentration. It is demonstrated that both contributions, which can be identified with the mechanisms of skew scattering and side displacement, can have the negative as wel as the positive sign.     

Noise annoyance from stationary sources: relationships with exposure metric day-evening-night level (DENL) and their confidence intervals

Relationships between exposure to noise [metric: day-evening-night levels (DENL)] from stationary sources (shunting yards, a seasonal industry, and other industries) and annoyance are presented. Curves are presented for expected annoyance score, the percentage "highly annoyed" (%HA, cutoff at 72 on a scale from 0 to 100), the percentage "annoyed" (%A, cutoff at 50 on a scale from 0 to 100), and the percentage "(at least) a little annoyed" (%LA, cutoff at 28 on a scale from 0 to 100). The estimates of the parameters of the relations are based on the data from a field study (N=1875) at 11 locations (2 shunting yards, 1 seasonal industry, 8 other industries) in the Netherlands. With the same (yearly) DENL, the seasonal industry causes less annoyance than the other industries, while the other industries cause less annoyance than the shunting yards. It appears that annoyance caused by vibrations from shunting yards and annoyance caused by noise from through trains are (partly) responsible for the relatively high annoyance from shunting yards. The relatively low annoyance from the seasonal industry presumably is related to the presence of a relatively quiet period. Results for the two shunting yards and the seasonal industry are based on fewer data than the other industrial sources, and are indicative. The same patterns of influence of age and noise sensitivity that are generally found are also found in this study. For comparison, results regarding transportation sources are also given, including previously unpublished results for expected annoyance.     

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.     

The heat of solution and interaction effects for noble gas atoms in metals

A simple model is presented from which the enthalpy of solution of noble gases in arbitrary metals can be estimated quantitatively.The heat of solution is derived as the interfacial energy at the contact interface between the metal and a noble gas atomic cell in solution.The model picture offers an explanation for the strong attraction between noble gas atoms, in particular helium, and vacancies, other noble gas atoms or metallic impurities with a low surface energy.     

The anomalous hall effect in nickel alloys: Contributions from skew scattering and side displacement in the two-current model

The anomalous Hall angle in ferromagnetic alloys contains two contributions, skew scattering and side displacement both of which depend on the source of electrical resistivity: φ_an = φ_sk + b?. Experimental data on φ_an for 250 binary and ternary nickel based alloys are analysed in terms of the two-current model. For a large number of solute metals, values for φ^↑_sk and φ^↓_sk are derived. It is observed that the value of b varies systematically with the fraction of the current carri ed by spin-up carriers. The results suggest that φ^↓_sk and b^↓_sk are of the same (positive) sign, while for the opposite spin direct ion they are both negative.