Hard X-ray techniques suitable for polymer experiments

Polymers have been studied since 1979 with 8-12 keV synchrotron radiation X-ray scattering methods and the number and sophistication of the experiments have rapidly grown ever since. More recently, new experimental techniques have been developed that use softer or harder X rays in less conventional ways. This article provides a brief overview of the possibilities of hard X-ray techniques and indicates some areas that might gain from further developments

Investigating the interstellar dust through the Fe K-edge

The chemical and physical properties of interstellar dust in the densest regions of the Galaxy are still not well understood. X-rays provide a powerful probe since they can penetrate gas and dust over a wide range of column densities (up to $10^{24}\ \rm{cm}^{-2}$). The interaction (scattering and absorption) with the medium imprints spectral signatures that reflect the individual atoms which constitute the gas, molecule, or solid. In this work we investigate the ability of high resolution X-ray spectroscopy to probe the properties of cosmic grains containing iron. Although iron is heavily depleted into interstellar dust, the nature of the Fe-bearing grains is still largely uncertain. In our analysis we use iron K-edge synchrotron data of minerals likely present in the ISM dust taken at the European Synchrotron Radiation Facility. We explore the prospects of determining the chemical composition and the size of astrophysical dust in the Galactic centre and in molecular clouds with future X-ray missions. The energy resolution and the effective area of the present X-ray telescopes are not sufficient to detect and study the Fe K-edge, even for bright X-ray sources. From the analysis of the extinction cross sections of our dust models implemented in the spectral fitting program SPEX, the Fe K-edge is promising for investigating both the chemistry and the size distribution of the interstellar dust. We find that the chemical composition regulates the X-ray absorption fine structures in the post edge region, whereas the scattering feature in the pre-edge is sensitive to the mean grain size. Finally, we note that the Fe K-edge is insensitive to other dust properties, such as the porosity and the geometry of the dust.Comment: 11 pages, 10 figures. Accepted for publication in Astronomy and Astrophysic

Past, present and future—sample environments for materials research studies in scattering and spectroscopy; a UK perspective

Small angle x-ray scattering and x-ray absorption fine structure are two techniques that have been employed at synchrotron sources ever since their inception. Over the course of the development of the techniques, the introduction of sample environments for added value experiments has grown dramatically. This article reviews past successes, current developments and an exploration of future possibilities for these two x-ray techniques with an emphasis on the developments in the United Kingdom between 1980–2020

Addressing decision making for remanufacturing operations and design-for-remanufacture

Remanufacturing is a process of returning a used product to at least original equipment manufacturer original performance specification from the customers' perspective and giving the resultant product a warranty that is at least equal to that of a newly manufactured equivalent. This paper explains the need to combine ecological concerns and economic growth and the significance of remanufacturing in this. Using the experience of an international aero-engine manufacturer it discusses the impact of the need for sustainable manufacturing on organisational business models. It explains some key decision-making issues that hinder remanufacturing and suggests effective solutions. It presents a peer-validated, high-level design guideline to assist decision-making in design in order to support remanufacturing. The design guide was developed in the UK through the analysis of selections of products during case studies and workshops involving remanufacturing and conventional manufacturing practitioners as well as academics. It is one of the initial stages in the development of a robust design for remanufacture guideline

Infrared activity of hydrogen molecules trapped in Si

The rovibrational-translational states of a hydrogen molecule moving in a cage site in Si, when subjected to an electrical field arising from its surroundings, are investigated. The wave functions are expressed in terms of basis functions consisting of the eigenfunctions of the molecule confined to move in the cavity and rovibrational states of the free molecule. The energy levels, intensities of infrared and Raman transitions, effects of uniaxial stress, and a neighboring oxygen defect are found and compared with existing experimental data

Assessment of sample preparation bias in mass spectrometry-based proteomics

For mass spectrometry-based proteomics, the selected sample preparation strategy is a key determinant for information that will be obtained. However, the corresponding selection is often not based on a fit-for-purpose evaluation. Here we report a comparison of in-gel (IGD), in-solution (ISD), on-filter (OFD), and on-pellet digestion (OPD) workflows on the basis of targeted (QconCAT-multiple reaction monitoring (MRM) method for mitochondrial proteins) and discovery proteomics (data dependent acquisition, DDA) analyses using three different human head and neck tissues (i.e. nasal polyps, parotid gland, and palatine tonsils). Our study reveals differences between the sample preparation methods, for example with respect to protein and peptide losses, quantification variability, protocol-induced methionine oxidation and asparagine/glutamine deamidation as well as identification of cysteine containing peptides. However, none of the methods performed best for all types of tissues, which argues against the existence of a universal sample preparation method for proteome analysis

Spatial distribution of precipitation recycling in the Amazon basin Elfatih

A free-boundary theory for the shape of the ideal dripping icicle Phys. Fluids 18, 083101 (2006) Grain growth theories and the isothermal evolution of the specific surface area of snow J. Appl. Phys. 95, 6175 (2004) Automated spectro-goniometer: A spherical robot for the field measurement of the directional reflectance of snow Rev. Sci. Instrum. 74, 5179 (2003) Comment on "Grain boundary ridge on sintered bonds between ice crystals" [J. Appl. Phys. 90, 5782 (2001)] J. Appl. Phys. 93, 783 (2003) Sintering in a dry snow cover J. Appl. Phys. 84, 4585 (1998) Additional information on AIP Conf. Proc. ABSTRACT Precipitation recycling is the contribution of evaporation within a large region to precipitation in that same region. The rate of recycling is a diagnostic measure of the coupling of land surface hydrology and regional climate. Here we describe the spatial and seasonal variability of the precipitation recycling process over the Amazon basin. The results are based on data of evaporation and water vapor fluxes from the European Center for Medium Range Weather Forecast (ECMWF). We estimate that 25% of all the rain that falls in the Amazon basin is contributed by evaporation within the basin. The contribution of recycled water vapor increases westward and southward with significantly different spatial distributions in the different seasons. INTRODUCTION Hydrology affects climate in many different ways. Evaporation provides the water vapor necessary for precipitation processes. Latent heat fluxes associated with evaporation and condensation provide an important energy transport mechanism in the Earth's atmosphere. Because land surface hydrology plays such a significant role in maintaining the equilibrium of regional climate, many recent studies t,2,3 suggest that anthropogenic changes in surface hydrology, e.g., deforestation of the Amazon basin, may result in serious impacts on climate. The precipitation recycling rate is a diagnostic measure of the current degree of coupling and the potential interactions of land surface hydrology and regional climate. Previous studies suggested different ways for computing precipitation recycling. Budyko 4 provides a spatially lumped estimate of precipitation recycling. It describes the seasonal but not the spatial distribution of the recycling rate. Lettau 5 describes precipitation recycling along a single streamline. We study both the spatial and seasonal variability of the recycling process. We consider two species of water vapor molecules; those which evaporate outside the region and molecules which evaporate within the region. The definition of the word 'region' includes all the area under study which is the Amazon basin. It is not restricted to the area of a single grid point. For a finite control volume of the atmosphere, conservation of mass requires the following relations