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Chemistry and physics have made major advances in recent years, yielding much more complex systems with high hierarchical order across multiple length scales. Accordingly, characterization tools are required that can elucidate the structure of such new materials over all length scales. Simultaneous small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) measurements are a unique tool to study such complexity and can be applied to very different fields of science. The OPUS (Option USANS) project is the study of a USANS option for SANS instruments, designed to be very versatile and easy to implement. The main idea is to provide the opportunity to study at the same time, and under the same experimental conditions, complex systems such as polymers, bio-systems, complex fibres and self-assembling systems. More specifically, this work presents the design of an option that could be applied to the suite of SANS instruments at the European Spallation Source (ESS) which will allow exploration of a Q range with a minimum Q down to one order of magnitude lower than the value attainable with the standard SANS instrument at the ESS. The proposed setup, based on the SAMBA (small-angle multi-beam analysis) approach, is very easy and fast to implement on a conventional SANS instrument and constitutes a multi-beam approach involving two multi-slits and a set of lenses near the sample position. This contribution describes all the focusing elements necessary to attain the proposed configuration and a detailed study using McStas simulations to optimize all the parameters involved for two SANS instruments: the future LoKI at the ESS and the present D11 at the Institut Laue–Langevin, the latter used as a benchmark for the model. Simulations performed without taking into account gravity effects show that the multi-beam approach allows extending the Q ranges to 9 × 10−5–7 × 10−4 Å−1 and 5 × 10−5–3 × 10−4 Å−1 for LoKI and D11, respectively.

The Ni-Mn-Ga ferromagnetic shape memory alloys (FSMAs) are a group of active materials that undergo martensitic transformations (MTs) induced by temperature, stress and/or magnetic fields, resulting in large recoverable mechanical deformations. Their fast response and high energy density make them ideal candidates for implementation in sensors and actuators. Recently, the development of high-temperature FSMAs (HTFSMAs), working at temperatures over 373 K, has become an important task to meet the current requirements of modern technologies. The magnetic and magnetoelastic properties of FSMAs are very sensitive to the interactions between the magnetic moments of atoms that, in turn, depend on the atomic positions within the lattice. Here we investigate a series of the polycrystalline Ni45Mn25-xGa20Co5Cu5Fex (x = 0, 1, 2 and 5 at%) HTFSMAs. Their MT and Curie temperatures, the crystal structures of the martensitic and austenitic phases, the temperature evolutions of the lattice parameters of both phases and the atomic site occupancies have been studied by means of powder neutron diffraction measurements, complemented by standard characterization techniques. Based on the atomic site occupancies and additional measurements of the saturation magnetization, the influence of the structure and atomic ordering on the magnetism in these materials is analysed. The most promising candidate for high temperature magnetic actuation is the alloy with Fe 5 at%, following a combination of the high MT and Curie temperatures, around 370 K and 440 K, respectively, with a low tetragonality ratio, c/a approximate to 1.16, in the proximity of MT. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

This work introduces an innovative, sustainable, and scalable synthesis of iron oxides nanoparticles (NPs) in aqueous suspension. The method, based on ion exchange process, consists of a one-step procedure, time and energy saving, operating in water and at room temperature, by cheap and renewable reagents. The influence of both oxidation state of the initial reagent and reaction atmosphere is considered. Three kinds of iron nanostructured compounds are obtained (2-lines ferrihydrite, layered-structure iron oxyhydroxide δ-FeOOH, and cubic magnetite), in turn used as precursors to obtain hematite and maghemite NPs. All the produced NPs are characterized by a high purity, small particles dimensions (from 2 to 50 nm), and high specific surface area values up to 420 m2/g, with yields of production &gt, 90%. In particular, among the most common iron oxide NPs, we obtained cubic magnetite NPs at room temperature, characterized by particle dimensions of about 6 nm and a surface area of 170 m2/g. We also obtained hematite NPs at very low temperature conditions (that is 2 h at 200 °C), characterized by particles dimensions of about 5 nm with a surface area value of 200 m2/g. The obtained results underline the strength of the synthetic method to provide a new, sustainable, tunable, and scalable high-quality production.

7 figures.-- Supplementary data available.-- © 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/, Crystallization under stringent cylindrical confinement leads to novel quasi-one-dimensional materials. Substances with strong cohesive interactions can eventually preserve the symmetries of their bulk phase compatible with the restricted geometry, while those with weak cohesive interactions develop qualitatively different structures. Frozen molecular deuterium (D2), a solid with a strong quantum character, is structurally held by weak dispersive forces. Here, the formation of one-dimensional D2 crystals under carbon nanotube confinement is reported. In contradiction with its weak cohesive interactions, their structures, scrutinized using neutron scattering, correspond to definite cylindrical sections of the hexagonal close-packed bulk crystal. The results are rationalized on the grounds of numerical calculations, which point towards nuclear quantum delocalization as the physical mechanism responsible for the stabilization of such outstanding structures., This work has been partly supported by the Spanish Agencia Estatal de Investigación (AEI), Fondo Europeo de Desarrollo Regional (FEDER, EU), Ministerio de Economía y Competitividad (MINECO), Ministerio de Ciencia, Innovación y Universidades (MCIU), under Grants No. MAT2016-75354-P (AEI/FEDER, EU), FIS2015-64654-P (MINECO/FEDER, EU), MAT2015-68394-R (MINECO/FEDER, EU), PGC2018-097018-B-I00 (MCIU/AEI/FEDER, EU), MAT2012-33633 (MINECO/FEDER, EU), MAT2012-39199-C02-02 (MINECO/FEDER, EU), by EU COST Action CM1405 “Molecules in Motion” (MOLIM), and by Spanish Ministerio de Ciencia e Innovación under Grants No. MAT2007-65711-C04-01, MAT2007-65711-C04-05, MAT2002-04540-C05-02, MAT2002-04540-C05-03, and MAT2002-04540-C05-04.

Ceramics are complex objects and a rich source of information: they constitute a large part of the staple memory of past and present human activities. A deep understanding of traditional ceramics is an essential key to designing new ceramic materials. The demanding synthesis of ceramics with fine-tuned properties, such as enhanced mechanical, electrical, optical or magnetic characteristics, must be associated with cutting-edge analysis procedures in order to improve the engineering process. In this context, we describe a neutron-based non-destructive approach to investigating the nanoporosity of an historical pottery matrix as an effective investigation technique for exploring both traditional and advanced ceramic materials. Fil: Mondelli, Claudia. Institut Laue Langevin; Francia Fil: Zorzi, Sandro. Universita' Ca' Foscari Di Venezia; Italia. Institut Laue Langevin; Francia Fil: Ricci, Giulia. Universita' Ca' Foscari Di Venezia; Italia Fil: Galván Josa, Víctor Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina Fil: Balliana, Eleonora. Universita' Ca' Foscari Di Venezia; Italia Fil: Schweins, Ralf. Institut Laue Langevin; Francia Fil: Cattaruzza, Elti. Universita' Ca' Foscari Di Venezia; Italia

The use of fuel cells is strategic in the global energy system; their inclusion in eco-cars, avoiding CO 2 emission, represents a crucial enhancement for the environment. For this reason, any improvement in their use and optimization is fundamental for our society. Since one of the main components in these cells is their polymeric proton exchange membrane, in this work, the commercial Fumapem F-14100 and F-1850 membranes have been studied, both representing a cheap and effective alternative in direct methanol fuel cell (DMFC) applications. Their characterization will provide a new insight about them, in order to optimize and improve future fuel cell operation conditions. Small angle neutron scattering (SANS) has been used in this work to achieve a nanometric structural characterization of these membranes, which is key for understanding their physicochemical properties. Starting from SANS measurements, empirical fitting models were applied in order to obtain global sample features, which allowed to propose a lamellar water channel structure. Then, 2D scattering length density maps generated by Monte Carlo simulations were optimized to match the experimental SANS intensity profiles by using the inverse Fourier transform method. In addition, the crystalline contribution from the sample ordered domains was also studied by using X-ray diffraction.

The synthesis, characterization and photoreduction ability of a new class of carbon dots made from fish scales is here described. Fish scales are a waste material that contains mainly chitin, one of the most abundant natural biopolymers, and collagen. These components make the scales rich, not only in carbon, hydrogen and oxygen, but also in nitrogen. These self-nitrogen-doped carbonaceous nanostructured photocatalyst were synthesized from fish scales by a hydrothermal method in the absence of any other reagents. The morphology, structure and optical properties of these materials were investigated. Their photocatalytic activity was compared with the one of conventional nitrogen-doped carbon dots made from citric acid and diethylenetriamine in the photoreduction reaction of methyl viologen.

Sodium montmorillonite (Na–Mt) was synthesized with the aim to investigate the adsorption and diffusion of hydrogen gas in a model smectite at high pressures (up to 90 bar) and non-cryogenic temperature (363 K). Na–Mt samples were synthesized from hydrogels in mild conditions (493 K and autogenous pressure). Two further Na–Mt samples with different levels of structural iron were prepared to investigate the effect of iron on the textural and hydrogen adsorption properties. Structural and elemental analyses confirmed that well crystalline smectite samples were obtained according to the nominal chemical formulae. Nitrogen adsorption–desorption isotherms revealed that the synthesized materials have specific areas in the range 90–120 m2/g and are mainly mesoporous. High pressure volumetric measurements showed that hydrogen absorption at 363 K saturated between 40 and 60 bar, reaching 0.2 ± 0.02 wt% (i.e. ∼1.0 mmol/g) at the plateau. Quasi-elastic neutron scattering revealed that hydrogen diffuses inside the clay porous network according to the Fick's law (continuous diffusion), while jump diffusion cannot be excluded at distances lower than 6.3 A, i.e. less than the one between two Na+ exchangeable ions. The hydrogen self-diffusion coefficients in the temperature range 25–300 K were determined to fall in the interval 0.1–1.0 · 10−7 m2 s−1. The results are compared with H2(g) adsorption and diffusion in other systems.

Ca(OH)2nanoparticles in hydro-alcoholic dispersion (nanolime) are currently used for eco-compatible treatments of carbonate-based substrates in the field of Cultural Heritage conservation. Unfortunately, at present nanolime is synthesized by processes which present some drawbacks (considerable cost, multiple steps, low specific production yield), thus limiting the potential of its applications. We have developed a single-step procedure, based on an ion exchange process, making it possible to produce pure and crystalline Ca(OH)2nanoparticles easily in water, at room temperature and ambient pressure, starting from cheap or renewable reactants. The simplicity of the process and its time- and energy-saving aspects are very promising factors for extending the production from lab to industrial scale. The aim of this paper is to investigate the structural and morphological features of the nanoparticles produced and to analyze the influence of crucial parameters of the synthesis process (i.e. time, water usage, reagent concentration and reaction volume) on the nanoparticles' characteristics. The nanolime produced is investigated by XRD, FTIR, TEM and AFM techniques. The nanoparticle reactivity in the carbonation process is also investigated, by varying the suspension concentration, the solvent and relative humidity conditions. Pure, crystalline and very reactive Ca(OH)2nanoparticles are obtained. The nanoparticles are constituted of thin lamellas, composed of primary hexagonal nanoparticles

Polarized neutron scattering has been used to obtain the magnetic moment at specific crystallographic sites of the austenitic and martensitic phases of two nonstoichiometric Ni-Mn-Ga single crystals with close composition. These alloys have been chosen because they exhibit different structures in the paramagnetic state and inverse positions of the respective martensitic transformation and Curie temperature. The diffraction analysis revealed a remarkable result: Despite the similar alloy composition, the magnetic moments of Mn are quite different for the two alloys at the same crystallographic position. Furthermore, such a difference enabled us to assess that the exchange coupling between Mn atoms switches from ferro- to antiferromagnetic at a distance between 2.92 and 3.32 Å in the martensite. These results are of great importance to guide first principles calculations that, up to now, have not been contrasted with experiments at the atomic level.

The Callovo-Oxfordian clay-rich rock formation is currently considered as host rock barrier in the French geological repository facility for radioactive waste (Meuse/Haute-Marne). After the closure of the facility, hydrogen gas is expected to develop mainly from anaerobic corrosion of steel containers and other ironcontaining structures. Gas pressure build-up could impact the safety of the repository. It is therefore important to acquire in-depth knowledge on the interaction between hydrogen gas and surrounding clay rock in terms of uptake ability and diffusion. Hydrogen uptake capacity was evaluated on dried clay rock samples: (i) at 20K, to allow for hydrogen liquefaction and determine the maximal Hy uptake of the clay, and (ii) at typical pressure and temperature conditions expected to develop in the repository (up to 363 K and a hydrogen pressure of 40-60 bar). H-2 absorption on the dried raw Callovo-Oxfordian start to saturate at about 30-40 bar, and the average adsorption above 40 bar is about 0.1% in weight. Quasi-elastic neutron scattering spectroscopy was used to study the diffusion mechanism of hydrogen gas in the clay rock at the microscopic scale and to determine hydrogen self-diffusion coefficients in the dry samples in the temperature range 25-300 K. Neutron data suggested that hydrogen diffuses in the dry clay rock according to Fick's law. The findings reported in this work can help to better understand the behavior of H-2 in clay rock samples. (c) 2014 Elsevier Ltd. All rights reserved.

The biological relevance of trehalose, glycerol, and their mixtures in several anhydrobiotic and cryobiotic organisms has recently promoted both experimental and simulation studies. In addition, these systems are employed in different industrial fields, such as pharmaceutical and cosmetic industries, as additives in mixtures for cryopreservation and in several formulations. This review article shows an overview of Inelastic Neutron Scattering (INS) data, collected at different temperature values by the OSIRIS time-of-flight spectrometer at the ISIS Facility (Rutherford Appleton Laboratory, Oxford, UK) and by the IN4 and IN6 spectrometers at the Institut Laue Langevin (ILL, Grenoble, France), on trehalose/glycerol mixtures as a function of the glycerol content. The data analysis allows determining the Boson peak behavior and discussing the findings in terms of fragility in relation to the bioprotective action of trehalose and glycerol.

This paper reports significant results about the effects of repeated treatments to protect a mediaeval Italian mortar from capillarity-absorbed water, by using for the treatments, our no-commercial hydro-alcoholic suspensions ofcalcium hydroxidenanoparticles(nanolime). The mortars samples came from the historical site, where preliminary thermographic inspection were performed to detect the damp zones. Before treatments, the samples were analyzed from a mineralogical and chemical point of view, by means of several techniques, asoptical microscopy(OM), thin section observations (PFM), porosimetric investigations, X-ray fluorescence (XRF), X-ray diffraction (XRD),infrared spectroscopy(FT-IR) and thermal analysis (TG-DTA). The size-grading curve of the aggregate and the binder/aggregate ratio were examined too. Then, the efficacy of nanolime protective treatments on this mortar versus the nanolime concentrations was investigated. For this aim, capillarity tests as well as porosimetric investigations, before and after the treatments, were performed. The obtained results were remarkably promising both in terms of the reduction of water absorbed by capillarity (up to 60%) together with an adequate decrease of porosity (up to 23%), fixing the protective effect of such eco-friendly and very compatible approach.

Calcium hydroxide nanoparticles in hydro-alcoholic dispersion are introduced as an effective conservation material for carbonatic substrates, thanks to their promising carbonation efficacy in ambient air. However, the current methods to synthesize such dispersions are characterized by some drawbacks that strongly limit applications. The aim of this work is to investigate structure, morphology and carbonatation efficacy of calcium hydroxide nanoparticles in aqueous suspension, produced by our alternative and original method of synthesis, based on the use of an ion exchange resin. Actually, the method allows to produce pure, nanosized and reactive Ca(OH)2 particles, operating at room temperature, without intermediate steps to eliminate undesired compounds, drastically reducing the time, and with a potential ability to be easily scaled up to provide larger amounts of nanoparticles. By X-ray diffraction techniques, we have investigated reactivity of the synthesized nanoparticles, in relation to the carbonatation process in air, by varying the suspension concentration. Preliminary results on the kinetics of the carbonatation process are presented too. Morphological analysis, performed by transmission electron microscopy, shows both hexagonal particles, often quarries, of side dimensions less than 100 nm, and spherical particles (

Today, one of the major challenges in biophysics is to disclose the molecular mechanisms underlying biological processes. In such a frame, the understanding of the survival strategies in extreme conditions received a lot of attention both from the scientific and applicative points of view. Since nature provides precious suggestions to be applied for improving the quality of life, extremophiles are considered as useful model-systems. The main goal of this review is to present an overview of some systems, with a particular emphasis on trehalose playing a key role in several extremophile organisms. The attention is focused on the relation among the structural and dynamic properties of biomolecules and bioprotective mechanisms, as investigated by complementary spectroscopic techniques at low- and high-temperature values.

In this work inelastic neutron scattering (INS) collected at different temperature values by the IN4 and IN6 spectrometers at the Institute Laue Langevin (ILL, Grenoble, France) on mixtures of two glass-forming bioprotectant systems, i.e. trehalose and glycerol, as a function of concentration are presented. The data analyses show that in the investigated mixtures the fast local dynamics, measured by INS, exhibits a switching-off maximum at very low glycerol content both at very low and very high temperature. This effect can be accounted for by a not-ideal mixing process of the pure constituents which gives rise to an increased hydrogen bonding network strength.

Neutron diffraction measurements on (Cs(2)O)(0.14)(B(2)O(3))(0.86) glass were performed at varying temperature over an extended range from room temperature to 800 K. It was found that, in the same Q range where the first sharp diffraction peak (FSDP) is observed in the static structure factor of almost all glass-forming systems, cesium borate glass shows two peaks. The intensities of these peaks increase with temperature, and their positions shift to lower Q values, in agreement with the peculiarities of the FSDP of network glasses. A description of this anomalous temperature dependence in terms of thermal relaxations of strained bonding arrangements of boron oxide units lying on the boundaries of cages present in the boron skeleton matrix is suggested. By comparing the diffraction patterns of a (Cs(2)O)(0.14)(B(2)O(3))(0.86) sample before and after a high-temperature thermal treatment with the spectra of cesium crystals, a correspondence between the medium-range structure in the glass and the related crystalline phases has been inferred.

The structures of the full series of alkali borate glasses (M(2)O)(x)(B(2)O(3))(1-x) (M = Li, Na, K, Rb and Cs) at two different concentrations, x = 0.14 and x = 0.30, have been investigated by means of molecular dynamics simulations. Additional compositions have also been investigated for the lithium and caesium borate glasses (x = 0.10, 0.20, 0.25, and 0.40). The main experimental trends are well reproduced by the simulations, even if the agreement is not quantitative. Our results indicate that lithium atoms can enter into the matrix of pure vitreous B(2)O(3) without inducing large modifications in the B-O network, even at large concentrations. However when the other alkali ions are added to the initial structure, the network opens to accommodate the larger size of the cation. These modifications induce the appearance of a low-Q shoulder or pre-peak, whose intensity increases with increasing alkali concentration as well as with increasing alkali size. (C) 2007 Elsevier B.V. All rights reserved.

Small-to-medium-angle neutron diffraction as well as a full neutron polarization study of CMR manganites of general formula La0.7Pb0.3(Mn1-xFex)O-3, from x = 0 up to x = 0.2, reveal the presence of nanometre-sized magnetic domains having characteristic dimensions about one order of magnitude smaller than the crystal grain sizes. The role played by such entities as main drivers of the magnetic ordering transition is established here by analysis of the diffraction data. The model employed is then validated from data derived from polarized neutron diffraction. The latter also provides a direct insight into the presence of antiferromagnetic regions that arise as a consequence of competing interactions brought about by Fe substitution on the Mn site. The results are finally discussed within the context of recent findings on related materials.

A study on the effect of Fe doping on the magnetic properties of La 0.7 Pb 0.3 Mn 1 - x Fe x O x , x = 0 and x = 0.2 perovskites is conducted using muon spectroscopy and macroscopic static magnetization measurements. For x = 0 , magnetization curves show a clear ferromagnetic component while a 20% Fe doping leads to the appearance of a kink in zero-field curves at low temperatures, attributed to progressive spin freezing together with a reduction of the ferromagnetic component. On dynamic grounds, we show that this effect translates into the appearance of non-exponential relaxation as T c is crossed from above.

The present neutron-scattering experimental findings concern with a study of fragility of trehalose, maltose, and sucrose/water mixtures. The fragility degree has been characterized by a new defini...

This work furnishes new experimental findings on glass-forming systems, i.e. homologues disaccharides (trehalose, maltose, sucrose)/H 2 O mixtures obtained by using elastic incoherent neutron scattering. Such a technique allows to characterize the different degree of “strength” of the investigated systems by means of the analysis of both the elastic intensity and the mean square displacement behaviours as a function of temperature and Q . The better cryptoprotectant effectiveness of trehalose in comparison with the other disaccharides is ascribed to lower fragility of the matrix in which biostructures are immersed, i.e. of the trehalose/water mixture.

In this work results on glass-forming systems, i.e. homologues disaccharides (trehalose, maltose, sucrose)/H2O mixtures obtained by using elastic incoherent neutron scattering are shown. The different degree of "strength" of the investigated systems, highlighted by the results, has been quantitatively characterized by using a new operative definition of "fragility". The connection between the fragility degree and the cryptoprotection degree is also discussed.

The use of calcium hydroxide nanoparticles (nanolime) in hydro-alcoholic suspensions represents a good enhancement in particular in the conservation of stones and surfaces of interest in Cultural Heritage. In this work we have produced nanolime by using our alternative method of synthesis (based on the use of a surfactant agent in the original solution) and we have studied, for the first time, structural and morphological properties of the synthesized nanoparticles directly in hydro-alcoholic suspension by synchrotron X-ray diffraction technique and transmission electron micro-scope observations. The particles characterization was performed on suspensions synthesized by varying surfactant content in the synthesis procedure and the water/alcohol ratio, too. We have found that only pure and crystalline Ca(OH)2 particles produced during the synthesis procedure and they maintained stably in suspension. These particles were hexagonally plated and regularly shaped with side dimension ranging from 300 to 40 nm or less; they had a platy habit and they presented, particularly with high alcohol content in suspension, a preferred orientation along z-axis.

In this work a route for BaZrO3 synthesis that assures homogeneity and stoichiometry of the final powder is proposed. The route consists in the complexation of the metallic ions by citric acid and ammonia in an aqueous solution. After an accurate drying of the initial solution, the crystalline phase of barium zirconate is obtained at relatively low temperature (about 700°C) and in relative short times utilising cheap starting reagents. A detailed description of the different steps of a preparation of 300 g of final product and a comparison with BaZrO3 powders produced by a typical solid state reaction are reported. The powders are characterised during the various steps by thermal analysis (DTA-TGA) and by structural and morphological techniques (XRD, FTIR and granulometric measurements). A preliminary investigation of the sintering process is reported: SEM imaging and dilatometric measurements were performed to evaluate different sintering behaviours of the powders prepared by wet and solid state methods.

Double exchange (DE)-mediated ferromagnetism in manganites, in which the Zener pair (Mn3+/Mn4+) is a key factor, is marked by the coexistence of the magnetic transition and the metal-insulator transition, thus distinguishing itself from superexchange (SE)-mediated ferromagnetism. Through detailed magnetization, transport and XAS studies, it was proposed by some of us that a unique magnetic pair-making effect occurs in Ru-substituted La0.6Pb0.4Mn1−xRuxO3 by virtue of variable valency of Ru and Mn. Ru ion, exhibiting a variable valency of Ru4+ and Ru5+, governs the DE-mediated coupling by initiating a magnetic pair-making effect with Mn3+ and Mn4+ states. Neutron diffraction measurements carried out on these compounds in the temperature range 4.2–500 K reveal the microscopic nature of magnetic ordering. Data obtained, in conjunction with data from other experimental techniques above, show that (i) Ru participates in the DE interaction with Mn for x⩽0.4, (ii) there is a weakening of DE due to depletion of Ru5+ for x>0.4, and (iii) SE ferromagnetic interactions are favored for x>0.4.

Calcium hydroxide nanoparticles in aqueous suspensions (also called nanolime) were successfully employed in Cultural Heritage conservation thanks to the ability of favoring readhesion of the pictorial layer on original carbonatic substrates or allowing to a better superficial cohesion and protection of treated stones. In this work, we have synthesized nanolime particles in aqueous suspension by two different methods. The produced particles were characterized in the laboratory, in terms of structural and morphological features, by means of X-Ray diffraction powder (XRD) and by transmission electron microscopy (TEM), respectively. Nanoparticles were crystalline, regularly shaped, hexagonally plated and with side dimensions generally ranging from 300 nm to 30 nm or less. Crystal structure of nanolime particles directly in the aqueous suspension, has been also analyzed by synchrotron diffraction from X-ray synchrotron radiation (SR-XRD); data have been analyzed by means of the Rietveld method and we have investigated the structure of Ca(OH)2 particles in suspension in terms of cell parameters, atomic coordinates, bond lengths and angles.

Results concerning the identification of a spin-glass transition in perovskites using the IN10 backscattering spectrometer at ILL are presented. The observed temperatures of these transitions agree with the previously obtained ones by means of DC and AC susceptibility measurements. Such a behaviour has been interpreted in terms of a transition from a polaronic liquid to a polaronic glass state.

The Maya blue (MB) is an artificial pigment created between 500-800 A.D. and used in murals, pottery and sculptures by Mayas and other people in Mesoamerica. MB is resistant to age, acid, weathering, biodegradation and even modern chemical solvents, but the chemical reasons behind the resistance to chemical aggressions are still under debate. Water plays a fundamental role in the interactions between indigo and clay. The dynamics of the clay's zeolitic and structural water molecules during the formation of MB, usually stabilized by moderate heating, has been monitored by means of neutron inelastic scattering. Neutron incoherent scattering in these samples is only due to the hydrogen atoms, so the signal is very sensitive to the amount of released water, providing detailed information on the dehydration process. A simultaneous analysis of the coherent elastic scattering and the incoherent scattering allows observing and quantifying how the structure of the clay is affected by dehydration. Here we show that a quite resistant pigment can be obtained at room temperature simply by dehydrating a palygorskite-indigo mixture employing only vacuum, without any thermal treatment.

In the present contribution, a procedure for molecular motion characterization based on the evaluation of the Mean Square Displacement (MSD), through the Self-Distribution Function (SDF), is presented. It is shown how MSD, which represents an important observable for the characterization of dynamical properties, can be decomposed into different partial contributions associated to system dynamical processes within a specific spatial scale. It is also shown how the SDF procedure allows us to evaluate both total MSD and partial MSDs through total and partial SDFs. As a result, total MSD is the weighed sum of partial MSDs in which the weights are obtained by the fitting procedure of measured Elastic Incoherent Neutron Scattering (EINS) intensity. We apply SDF procedure to data collected,by IN13, IN10 and IN4 spectrometers (Institute Laue Langevin), on aqueous mixtures of two homologous disaccharides (sucrose and trehalose) and on dry and hydrated (H2O and D2O) lysozyme with and without disaccharides. It emerges that the hydrogen bond imposed network of the water-trehalose mixture appears to be stronger with respect to that of the water-sucrose mixture. This result can justify the higher bioprotectant effectiveness of trehalose. Furthermore, it emerges that partial MSDs of sucrose and trehalose are equivalent in the low Q domain (0÷1.7) Å−1 whereas they are different in the high Q domain (1.7÷4) Å−1. This suggests that the higher structure sensitivity of sucrose should be related to the small spatial observation windows. Moreover, the role of the instrumental resolution in EINS is considered. The nature of the dynamical transition is highlighted and it is shown that it occurs when the system relaxation time becomes shorter than the instrumental energy time. Finally, the bioprotectants effect on protein dynamics and the amplitude of vibrations in lysozyme are presented.

Quantum crystals are characterized by zero-point-energy motions large enough to explore the details of the interaction potential beyond the harmonic approximation even at zero temperature. By making recourse to ultrahigh-resolution neutron spectroscopy, we have probed simultaneously three observables sensitive to anharmonic effects in solid para-H 2 over a wide temperature range, namely, Bragg scattering, molecular root-mean-square displacements, and the spectral linewidth of the J=0→ 1 rotational transition which, on average, amounts to a half-width at half-maximum of 1.8±0.2 οeV. These three quantities show no measurable variation with temperature, thus signaling the existence of a fully expanded crystal across the entire solid phase. Our results provide unambiguous experimental evidence for the intrinsic quantum character of this fundamental molecular solid. © 2012 American Physical Society., Work supported in part by Grant No. MAT2007-65711- C04-01 from the Spanish Ministerio de Ciencia e Innovación. FFA gratefully acknowledges the UK Science & Technology Facilities Council for financial support

The main aim of the present work is to investigate the dynamical effects of the addition of disaccharides to hydrated lysozyme. The Self-Distribution-Function procedure is at first applied on Elastic Incoherent Neutron Scattering data obtained by the IN13 spectrometer on trehalose/H(2)O and sucrose/H(2)O where it highlights a different Q-dependence for the two disaccharides. Then a quantitative analysis of the Mean Square Displacement of lysozyme/trehalose/H(2)O and of lysozyme/sucrose/H(2)O from Elastic Incoherent Neutron Scattering data obtained by the IN10 spectrometer is presented. It is shown how the resolution function gives rise to a time integration of a given time-dependent Mean Square Displacement function. Furthermore the analysis shows that the protein dynamical transition, registered at a temperature value of about T = 200-220 K in the H(2)O hydrated lysozyme sample, is inhibited by the addition of the disaccharides. (C) 2010 Elsevier B.V. All rights reserved.

By using the fixed energy window method in incoherent elastic neutron scattering, molecular motions in the 150 ps timescale in highly oriented multilayers of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) membranes in excess of water (D2O) have been studied as a function of temperature, in the range from 27 to 325 K. The same system in partially deuterated form and with the addition of a pore-forming peptide (gramicidin) has also been investigated. By proper orientation of the membrane plane with respect to the scattering wavevector Q, information on in plane and out of plane motions of lipid membranes have been derived. Two relevant dynamical transitions were observed at T = 297 K and at T = 270 K. The former is related to the structural main transition from gel to liquid phase of the phospholipid bilayer, while the latter is related to a transition of the aqueous solvent. The inclusion of gramicidin shifts the main transition down to 294 K and the second transition up to 276 K. In both cases the observed dynamical transitions show an enhanced mobility in the direction normal to the membrane plane.

The aim of the present work is to investigate the chemical physics mechanisms of protein stabilization by homologous disaccharides (trehalose, maltose and sucrose). On this purpose the structural and dynamical properties of dUTPase-inhibitor candidate and dUTPase-inhibitor candidate/disaccharide mixtures have been investigated by elastic neutron scattering (ENS), quasi-elastic neutron scattering (QENS) and photon correlation spectroscopy (PCS). The decrease in the ENS intensity profiles vs temperature for the disaccharide-water mixtures is less marked in the case of trehalose/ water mixture. This indicates that trehalose shows a larger structural resistance to temperature changes and a higher 'rigidity' in comparison with maltose/H2O and sucrose/H2O Mixtures. In addition the protein/hydrated-disaccharide mixtures show a linear dependence between the solvent viscosity and the local mean-square displacement of hydrated dUTpase/disaccharide systems. This result shows that the protein dynamics is coupled with that of the surrounding matrix. Furthermore, QENS results on the binary disaccharide-H2O/D2O mixtures indicate that the water dynamics is affected by all the disaccharides and particularly by trehalose. Finally, PCS findings indicate that the protein hydrodynamic radius in solution does not change at low disaccharide concentrations, while reveal, at high disaccharide concentration, a breakdown of the Stokes-Einstein law. The experimental findings are discussed and interpreted in the frame of the current theories. (C) 2007 Elsevier B.V. All rights reserved.

The spin dynamics of substituted colossal magnetoresistive (CMR) manganites of general formula ${\mathrm{La}}_{0.7}{\mathrm{Pb}}_{0.3}({\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x}){\mathrm{O}}_{3}$, $0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.2$ is investigated by means of neutron spin-echo measurements. Substitution of Mn by Fe leads to a strong decrease of the temperature of macroscopic magnetic long-range ordering with a concomitant enhancement of the CMR effect. For $x=0.2$, a long-range-ordered state is not achieved as a result of the increase in antiferromagnetic interactions brought forward by ${\mathrm{Fe}}^{+3}$-Mn couplings. The results display two relaxations having well separated decay constants. A fast process with a relaxation time of about $10\phantom{\rule{0.3em}{0ex}}\mathrm{ps}$ within the paramagnetic phase is found for all compositions. It shows a remarkably strong dependence with temperature and sample composition as the apparent activation energy for spin diffusion as well as the preexponential term exemplify. The physical origin of such a fast relaxation is assigned to heavily damped or overdamped spin waves (spin diffusion) on the basis of some signatures of excitations having finite frequencies found for the parent compound ${\mathrm{La}}_{0.7}{\mathrm{Pb}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}$ at temperatures just below ${T}_{c}$, together with preliminary data on the effect of Fe doping on the stiffness constant. A slower relaxation is present for all compositions. Its temperature dependence follows the behavior of the macroscopic magnetization, and its intensity grows within the ordered ferromagnetic state. Its physical origin is ascribed to collective reorientation of nanoscale ferromagnetic domains on the basis of the wave-vector dependence of its relaxation rate and amplitude.

The chemical order of three off-stoichiometry Ni–Mn–Ga compositions has been measured in the austenitic phase using powder and single-crystal neutron diffraction. The compositions studied, 48–52 at.% nickel, having excess manganese and deficient in gallium, are of technical interest due to the observed large room-temperature, magnetic-field-induced strain. It has been determined that compositions with less than 50% nickel have the excess Mn atoms occupying Ni and Ga sites. Compositions enriched in nickel are best fit with Ni atoms in excess of 50% occupying Mn sites while the excess and displaced Mn occupy Ga sites. The saturation magnetic moments calculated from the site occupations determined here and using Ni and Mn moments reported for Ni2MnGa, agree within 4% with the low-temperature measured moments.

The spectrum of collective excitations of liquid deuterium in the bulk and confined within a MCM-41 matrix having pores of an average diameter of 2.4 nm has been studied by means of neutron scattering and molecular dynamics simulations. The main effects of confining liquid D-2 consist in a shift of the characteristic frequencies associated with damped density oscillations to higher energies. A strong decrease in diffusivity is also observed upon confinement.

4 págs.; 3 figs.; Open Access funded by Creative Commons Atribution Licence 3.0; 7th Meeting of the Spanish Neutron Scattering Association (SETN), Recent neutron scattering measurements have revealed that para-Hydrogen prepared in its fundamental state solidifies in a crystal that do not show temperature response (temperature independent molecular displacement and first rotational level linewidth as well as negligible thermal expansion). Here, it is argued that such unique behaviour in the crystal phase can be understood if the crystallization is driven by pure quantum fluctuations., Work supported in part by grants MAT2007-65711-C04-01 and MAT2012-33633 from the Spanish Ministerio de Economía y Competitividad.

The crystal and magnetic structures of (Pr0.55Ca0.45)(Mn1-yCry)O3 (y = 0.00, 0.03, 0.06) have been investigated between 5 and 300 K by means of neutron powder diffraction followed by Rietveld refinement and dc magnetic measurements. An orthorhombic-to-monoclinic phase transition occurs on cooling in (Pr0.55Ca0.45)MnO3; at lower temperature charge ordering in the Mn sub-lattice, coupled with orbital ordering, induces an anti-ferromagnetic (AFM) spin ordering within the monoclinic phase. Cr substitution at the Mn site hinders the phase transition, although for the y = 0.03 sample small amounts of the monoclinic phase co-exist at low temperature with the main phase characterized by an orthorhombic structure. In addition Cr favours ferromagnetism (FM) participating to the double exchange mechanism. Cr substitution prevents charge ordering, favouring double exchange and hence FM spin ordering within the Mn sub-lattice. The Curie temperature of the Cr substituted samples is independent on the Cr content.

We present a comparative study of the excitations in bulk and liquid ${\mathrm{D}}_{2}$ confined within the pores of MCM-41. The material (Mobile Crystalline Material-41) is a silicate obtained by means of a template that yields a partially crystalline structure composed by arrays of nonintersecting hexagonal channels of controlled width having walls made of amorphous ${\mathrm{SiO}}_{2}$. Its porosity was characterized by means of adsorption isotherms and found to be composed by a regular array of pores having a narrow distribution of sizes with a most probable value of $2.45\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. The assessment of the precise location of the sample within the pores is carried out by means of pressure isotherms. The study was conducted at two pressures which correspond to pore fillings above the capillary condensation regime. Within the range of wave vectors where collective excitations can be followed up $(0.3\ensuremath{\leqslant}Q\ensuremath{\leqslant}3.0\phantom{\rule{0.3em}{0ex}}{\mathrm{\AA{}}}^{\ensuremath{-}1})$, we found confinement brings forward a large shortening of the excitation lifetimes that shifts the characteristic frequencies to higher energies. In addition, the coherent quasielastic scattering shows signatures of reduced diffusivity.

Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose's supramolecular structure, which allows access to degradation agents, in ancient and modern samples. For the first time, SANS data were interpreted in terms of water-filled pores, with their sizes increasing from 1.61 nm up to 1.97 nm in natural and artificially aged papers. The protective effect of gelatine sizing was also observed.