Size-strain separation in diffraction line profile analysis.

Separation of size and strain effects on diffraction line profiles has been studied in a round robin involving laboratory instruments and synchrotron radiation beamlines operating with different radiation, optics, detectors and experimental configurations. The studied sample, an extensively ball milled iron alloy powder, provides an ideal test case, as domain size broadening and strain broadening are of comparable size. The high energy available at some synchrotron radiation beamlines provides the best conditions for an accurate analysis of the line profiles, as the size-strain separation clearly benefits from a large number of Bragg peaks in the pattern; high counts, reliable intensity values in low-absorption conditions, smooth background and data collection at different temperatures also support the possibility to include diffuse scattering in the analysis, for the most reliable assessment of the line broadening effect.

Powder diffraction in Bragg-Brentano geometry with straight linear detectors.

A common way of speeding up powder diffraction measurements is the use of one- or two-dimensional detectors. This usually goes hand in hand with worse resolution and asymmetric peak profiles. In this work the influence of a straight linear detector on the resolution function in the Bragg-Brentano focusing geometry is discussed.

Treating childhood obesity.

Nearly a third of children and adolescents are overweight or obese, which puts them at higher risk for diseases such as hypertension, type 2 diabetes, stroke, coronary heart disease and some cancers. This article discusses strategies physicians can use to address the issue of weight with children and their families. It also describes the efforts of a Minnesota collaborative that is working to improve obesity care and ensure insurance coverage for it.

Evolution of internal stresses in the plain ferritic steel studied by neutron diffraction in situ upon tensile straining.

The present in situ neutron diffraction study aims to investigate the response of selected lattice planes in the polycrystalline material upon tensile loading. For this purpose, the 0.1C-0.