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Impact of tsunami inundation on soil salinsaltion - up to one year after the 2011 Tohoku-okitsunami
No full textThe long-term effect of tsunami inundation on soil salinisation was assessed following the 2011 Tohoku-oki tsunami in two areas on the Sendai Plain, near Sendai airport in the Miyagi Prefecture and Matsukawa-ura near Soma in the Fukushima Prefecture. Data gathered over four sampling seasons 2, 5, 9 and 11 months after the tsunami near Sendai airport show that the salt content generally decreased with time. Concentrations were nevertheless higher in February 2012 than in October 2011, probably due to capillary action and evaporation following long periods with little precipitation in the winter, while the lower concentrations in October were attributed to dilution due to intense rainfall prior to the sampling period. In February 2012, the area with chloride concentrations over the guidelines for the establishment of rice seedlings still extended for nearly 1 km between 2.45 and 3.33 km inland. Chloride concentrations also reached the guideline values at the land surface 1.71 km inland. This corresponded to the limit of the area deemed not suitable for rice production by local rice farmers. However, recent observations revealed that rice crops were not only halted in 2011 but also in 2012, probably due to high salinisation of soil and/or surface and groundwater. Our study shows that soil salinisation was still recorded to nearly 15 cm depth in areas with fine-grained organic-rich soil ~2.5 km from the shoreline 11 months after the tsunami, and that water-leachable ions were preferentially retained in organic-rich muddy sediment and soil, reflecting the long-term impact of tsunami inundation. In Matsukawa-ura, salt crusts still covered the area flooded by the tsunami in February 2012 and both the soil and muddy tsunami deposit were characterised by high chloride and sulphate concentrations. The latter might also lead to sulphide toxicity. Remediation measures have been implemented in certain areas, but further research needs to be carried out to test the effectiveness of the measures being used to allow rice production to resume. © 2014, Springer Science+Business Media Dordrecht
Neutron tomographic analysis: Material characterization of silver and electrum coins from the 6th and 5th centuries BCE
No full textNeutron tomography was applied to study a set of Greek silver coins and a single Lydian electrum coin minted in the 6 and 5th centuries BCE. The investigation was conducted at the new neutron imaging station DINGO at ANSTO in order to demonstrate capabilities and to explore limits of this non-invasive method in characterizing numismatic materials. From the reconstructed volume of each sample, the morphology, porosity, inclusions, and presence of composite structures can be revealed and evaluated. This information can be used to elucidate ancient minting technology and to prove authenticity. Moreover, the state of conservation, corrosion processes and attempts to repair the coins can be determined. © 2016 Elsevier Inc
Introduction to the special issue for the 15th International Conference on Small-Angle Scattering (SAS2012)
Get PDFThe scientific publishing landscape is changing. Over the past few meetings of the
small-angle scattering community, it has become challenging for conference organizers to
publish traditional volumes of proceedings in scientific journals without impacting on
metrics of concern to many publishing houses, namely impact factor, despite an expressed need to have proceedings. Equally, many scientists would choose not to submit their
findings to proceedings and wish to communicate their work in high-impact-factor
journals only. From broadly canvassing the community, it has become evident that both
proceedings and selected articles have their own rightful place and are valuable sources
of reference for both the newcomer to the field and established researchers alike. As
such, for the first time, the organizers of the small-angle scattering conference have
published both proceedings (McGillivray et al., 2012) – reflecting the full content of the
meeting and reviewed to the extent that the work has been selected for conference
presentation – and, here, a special issue in what many would consider to be the traditional
and natural home for small-angle scattering, namely Journal of Applied Crystallography.
The production of this special issue has been a painstaking process. Attendees were
invited to submit articles on the basis that, not only would their work be exposed to
rigorous review but, even then, only selected articles would be published. The refereeing
process was strict and thorough, many papers were rejected, and all were improved. We
are grateful to all the authors that submitted material, whether selected or not, as well as
the Guest Co-editors – Andrew Jackson, Yoshiyuki Amemiya, Charles Dewhurst, Dmitri
Svergun and Aldo Craievich – the many referees for their invaluable effort which made
the publication of this special issue possible and, indeed, the entire scientific programme
committee that developed such a compelling programme. We would also like to thank
Lisa Stephenson and Peter Strickland at the IUCr Editorial Office in Chester, UK, for
their support and guidance. The resulting compilation provides an excellent overview of
the state of the art across the spectrum of small-angle neutron and X-ray scattering
(SANS and SAXS), covering the fields of application, theory, methods of analysis and
instrumentatio
Surface-to-mountaintop transport characterised by radon observations at the Jungfraujoch
Get PDFAtmospheric composition measurements at Jungfraujoch are affected intermittently by boundary-layer air which is brought to the station by processes including thermally driven (anabatic) mountain winds. Using observations of radon-222, and a new objective analysis method, we quantify the land-surface influence at Jungfraujoch hour by hour and detect the presence of anabatic winds on a daily basis. During 2010–2011, anabatic winds occurred on 40% of days, but only from April to September. Anabatic wind days were associated with warmer air temperatures over a large fraction of Europe and with a shift in air-mass properties, even when comparing days with a similar mean radon concentration. Excluding days with anabatic winds, however, did not lead to a better definition of the unperturbed aerosol background than a definition based on radon alone. This implies that a radon threshold reliably excludes local influences from both anabatic and non-anabatic vertical-transport processes. © Author(s),2014
Measurement of residual stresses in titanium aerospace components Formed via Additive Manufacturing
No full textIn the present study gas tungsten arc welding (GTAW) with automated wire addition was used to additively manufacture (AM) a representative thin-walled aerospace component from Ti-6Al-4V in a layer-wise manner. Residual strains, and hence stresses, were analysed quantitatively using neutron diffraction techniques on the KOWARI strain scanner at the OPAL research facility operated by the Australian Nuclear Science and Technology Organisation (ANSTO). Results showed that residual strains within such an AM sample could be measured with relative ease using the neutron diffraction method. Residual stress levels were found to be greatest in the longitudinal direction and concentrated at the interface between the base plate and deposited wall. Difficulties in measurement of lattice strains in some discrete locations were ascribed to the formation of the formation of localised texturing where α-Ti laths form in aligned colonies within prior β-Ti grain boundaries upon cooling. Observations of microstructure reveal basket-weave morphology typical of welds in Ti-6Al-4V. Microhardness measurements show a drop in hardness in the top region of the deposit, indicating a dependence on thermal cycling from sequential welds. © 2014, Trans Tech Publications
The effect of the crystallographic texture on intergranular stress corrosion crack paths
No full textIntergranular stress corrosion cracking (IGSCC) crack paths usually travel perpendicular to the applied load direction. Some instances of crack paths propagating in directions away from the perpendicular have been observed in low carbon steels. This study shows that the crystallographic texture is a critical factor that drives the IGSCC crack path. Residual shear strain induced by shear texture (induced by rolling processes) explains the inclination of the cracks at a certain depth and the continuous propagation of the cracks along the transverse directions. The residual strains coming from the manufacturing processes determine the crack propagation paths. © 2014, Elsevier B.V
Uptake and cellular distribution, in four plant species, of fluorescently labeled mesoporous silica nanoparticles
No full textMonodispersed mesoporous silica nanoparticles (MSNs) of optimal size and configuration were synthesized for uptake by plant organs, tissues and cells. These monodispersed nanoparticles have a size of 20 nm with interconnected pores with an approximate diameter of 2.58 nm. There were no negative effects of MSNs on seed germination or when transported to different organs of the four plant species tested in this study. Most importantly, for the first time, a combination of confocal laser scanning microscopy, transmission electron microscopy and proton-induced X-ray emission (micro-PIXE) elemental analysis allowed the location and quantification MSNs in tissues and in cellular and sub-cellular locations. Our results show that MSNs penetrated into the roots via symplastic and apoplastic pathways and then via the conducting tissues of the xylem to the aerial parts of the plants including the stems and leaves. The translocation and widescale distribution of MSNs in plants will enable them to be used as a new delivery means for the transport of different sized biomolecules into plants. © 2014, Springer-Verlag Berlin Heidelberg
Neutron diffraction study of MnNiGa2—Structural and magnetic behaviour
No full textMnNiGa2 crystallizes in the L21 (Heusler) structure and has a ferromagnetic ordering temperature TC ∼ 192 K. Rietveld refinement of the neutron diffraction patterns indicates that the Ga atoms occupy the equivalent 8c position, while Mn and Ni share the 4a (0, 0, 0) and 4b (0.5, 0.5, 0.5) sites with a mixed occupancy of Mn and Ni atoms. It is found that that ∼83% of Mn and ∼17% Ni are located at the 4a site while ∼83% of Ni and ∼17% Mn occupy the 4b site. There is no evidence of a magneto-volume effect around TC. In agreement with this finding, our detailed critical exponent analyses of isothermal magnetization curves and the related Arrott plots confirm that the magnetic phase transition at TC is second order. © 2014,AIP Publishing LLC
Single-crystal neutron diffraction and Raman spectroscopic study of hydroxylherderite, CaBePO4(OH, F)
No full textThe crystal structure, H bonding and chemical composition of hydroxylherderite from the Bennett pegmatite, Buckfield, Oxford County, Maine, USA were investigated by single-crystal X-ray diffraction and neutron Laue diffraction, electron microprobe analysis in wavelength-dispersive mode, inductively coupled plasma-atomic emission spectrometry and polarized Raman spectroscopy [ Ca (Na0.01Ca1.01)Σ1.02 Be (Be0.98Li0.01)Σ0.99 P (Si0.03P0.98)Σ1.01O4(OH0.67F0.33)Σ1, Z = 4, a = 9.7856(5), b = 7.6607(5), c = 4.8025(3) Å, b = 90.02(3)°, V= 360.02(4) Å3, space group P21/a]. The neutron-structure refinement converged with fully anisotropic displacement parameters to give a final agreement index R 1 = 0.0363 for 85 refined parameters and 1614 unique reflections with F o >4σ(F o). The structure refinement was used to determine the H position and geometry of H bonding in the structure. One H site was found on the O5 anion with an O–H interatomic distance, corrected for “riding motion”, of 0.996(2) Å. The H bond of hydroxylherderite is bifurcated with O2 and O4 acceptors forming H bonds with O5···O2 = 3.163(1) Å, H···O2 = 2.544(2) Å and O5–H···O2 = 121.8(1)°; O5···O4 = 3.081(1) Å, H···O4 = 2.428(2) Å and O5–H···O4 = 124.4(1)°. The highly non-linear O–H···O hydrogen bonds in hydroxylherderite and in the isotypic datolite [ideally CaBSiO4(OH)] are constrained by the tetrahedral network topology. Two main O–H stretching modes were observed in the Raman spectra at 3565 and 3620 cm–1, which are attributed to the bifurcated H bond. Two additional weak bands at 3575 and 3610 cm–1 are attributed to Si–P disorder in the tetrahedral sites. Results of this study will contribute to the correlation of H-bonding geometry and O–H stretching frequencies of highly non-linear H bonds.© The Mineralogical Society of Great Britain & Ireland
High coverage fluid-phase floating lipid bilayers supported by ω-thiolipid self-assembled monolayers
Get PDFLarge area lipid bilayers, on solid surfaces, are useful in physical studies of biological membranes. It is advantageous to minimize the interactions of these bilayers with the substrate and this can be achieved via the formation of a floating supported bilayer (FSB) upon either a surface bound phospholipid bilayer or monolayer. The FSB's independence is enabled by the continuous water layer (greater than 15 Å) that remains between the two. However, previous FSBs have had limited stability and low density. Here, we demonstrate by surface plasmon resonance and neutron reflectivity, the formation of a complete self-assembled monolayer (SAM) on gold surfaces by a synthetic phosphatidylcholine bearing a thiol group at the end of one fatty acyl chain. Furthermore, a very dense FSB (more than 96%) of saturated phosphatidylcholine can be formed on this SAM by sequential Langmuir–Blodgett and Langmuir–Schaefer procedures. Neutron reflectivity used both isotopic and magnetic contrast to enhance the accuracy of the data fits. This system offers the means to study transmembrane proteins, membrane potential effects (using the gold as an electrode) and even model bacterial outer membranes. Using unsaturated phosphatidylcholines, which have previously failed to form stable FSBs, we achieved a coverage of 73%. © 2014 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0/, which permits unrestricted use, provided the original author and source are credited