Papers by Keyword: SAXS

Abstract: Main initiative of this study is to report the changes occurred in the particle size and distribution of nano-hydroxyapatite powders due to the novel effect of Plant Leaf Mediated Natural Extracts (PLMNEs). Wet-Chemical precipitation method is used to obtain homogeneous nano-hydroxyapatite powders. These nano-hydroxyapatite powders have been synthesized by using different precursors and relative concentrations. The natural extracts used as Natural Stabilizers (NSs) are derived from Soya Leaves (SL) and Spinach Leaves (SpL) for the preparation of nano-hydroxyapatite. Present study reports the morphological changes in nano-hydroxyapatite and has been characterized using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Small Angle X-Ray Scattering (SAXS). Till now no studies have been reported on synthesis of nano-hydroxyapatite using Plant Leaf Mediated Natural Extracts as precursors. The Natural Stabilizers used have been found to show evidence of several medicinal effects.

Abstract: The fibrillation mechanism of insulin in acid solution has been studied by small angle X-ray scattering (SAXS). It was observed that insulin monomer unfolded in both conditions. Furthermore, in zinc free solution, insulin tend to aggregate on heating start in the first 5 min. The fibrillation through aggregation process continues until 30 min on heating. The similar phenomenon occurs in the presence of zinc ions. The SAXS data suggest that the presence of zinc ions prevent the long cylindrical fibril at the beginning of heating. However, after 20 min heating, the large cylindrical fibril of insulin formed in both conditions.

Abstract: The performance of graphene/polymer nanocomposites depends on many factors but the major factor is a nanoparticles dispersion and distribution into the host matrix. The present work investigates the effect of the dispersion of graphene oxide upon the structure-property relations in metallocene linear low density polyethylene (PE), homo polypropylene (PP), and blends thereof. These nanocomposites were prepared by solvent processing, where DMF and o-xylene were used as solvents for Graphene Oxide (GO) powder and the polymers respectively, before the two components were combined to form a well-mixed initial state. Characterization of the structure and crystallization of the nanocomposites was carried out by small- and wide-angle X-ray scattering and diffraction (SAXS and WAXD). The chemical structures were characterized by Fourier transform infrared spectroscopy (FTIR) and by Raman spectroscopy, and the latter used to calculate the ID/IG value for a pure GO samples. The thermal properties of the resulting nanocomposites were investigated by DSC and TGA in order to obtain Melting temperature ( ), crystallization temperature ( ) and degree of crystallinity ( ) as well as a range of degradation temperatures. The effect of GO on the mechanical properties was studied via the ultimate tensile strength and elastic modulus.

Abstract: Fe₃O₄/Carboxymethyl Cellulose (CMC)/Polyvinyl Alcohol (PVA) hydrogel magnetic was successfully synthesized by using the freezing-thawing process. Meanwhile, the filler of Fe₃O₄ nanoparticles was successfully fabricated by co-precipitation method. Magnetic hydrogel and Fe₃O₄ was revealed by using X-Ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), Vibrating Sample Magnetometer (VSM), and Small Angle X-ray Scattering (SAXS) to investigate the content of elements in the Fe₃O₄ filler, the functional group network of samples, magnetic properties of magnetic hydrogel and Fe₃O₄, and nanostructure of magnetic hydrogel, respectively. The magnetic properties of magnetic hydrogel decreased as the decrease in the particle sizes of the Fe₃O₄ nanoparticles. On the other hand, the saturation magnetization of magnetic hydrogel decreased as the freezing-thawing route increased in number. This condition can be concluded that the distribution of the Fe₃O₄ filler in CMC/PVA magnetic hydrogel was more effective when the route number of freezing-thawing reached the maximum process (7x processes). Moreover, the nanostructure of magnetic hydrogel revealed the composition of the crystalline phase of CMC/PVA hydrogel of approximately 6 nm. By these characteristics, Fe₃O₄/CMC/PVA magnetic hydrogel is potential to be used as smart gel such as artificial muscle, switch-of, and the others.

Abstract: The information provided by different characterisation methods when measuring particle size varies depending on the chosen technique and analytical approach (e.g. light scattering, transmission electron microscopy, spectroscopy, x-ray scattering). This in turn has an impact on the accuracy of the results as well as comparability between methods and overall confidence on the analyses. The present study used a common sol-gel reaction to synthesise amorphous silica nanoparticles (aSiNPs) and characterised the product purity and homogeneity. The reaction involved hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in the presence of lysine, which acted as catalyst for the silica production and also as a capping agent for particle size control in a suspension kept at pH 8-10. According to DLS data, the stock suspension was stable for at least 6 months in Milli Q water without surfactant when kept at 4°C. This study focused on multi-method size and shape characterisation of the aSiNPs, involving the following techniques: DLS, TEM, FTIR, STEM and SAXS. These techniques provided information on hydrodynamic diameter, core particle dimensions, sphere equivalent size, and radius of gyration. Our results show two particle populations, one around 2 nm and the other around 7 nm in diameter. Notably, these two populations are not resolved (i.e. “visible”) by all methods used.

Abstract: Powders consisting of nanoparticles of zinc peroxide were prepared via a simple hydrothermal process using zinc acetate dihydrate and hydrogen peroxide precursors. The size of the crystallites was determined using x-ray powder diffraction. Over a period of 5 hours the crystallite radius increased from 4 nm – 9 nm at a temperature of 68 °C ± 5 °C, with growth rate constant of 0.23 nm³ min⁻¹ calculated using the Lifshitz, Slyozov, and Wagner model. The powders were further characterised with High Resolution Transmission Electron Microscopy, Energy Dispersive X-ray analysis, and Small Angle X-ray Scattering, showing well-crystallised ZnO₂ nanoparticles.

Abstract: We follow changes in the micro structure at several distances from the weld nugget of friction stir welded AlCuLi-alloy (AA2198) plates occurring due to the tool movement and the created heat by employing different methods: Small Angle X-ray Scattering (SAXS), giving information on type, size and density of precipitates, Differential Scanning Calorimetry (DSC), giving information on formed precipitates by their dissolution signal, and positron annihilation lifetime spectroscopy (PALS), being sensitive to vacancies and dislocations as well as to the formation and growth of precipitates. We start by characterizing the base material as a reference and proceed via the heat-affected zone to the weld nugget. By the use of complementary methods, we obtain information on structure, kind and distribution of precipitates and correlate this with hardness measurements.

Abstract: The data on atomic and electronic structure and some magnetic properties of graphite domains in activated carbon fibers (ACF) are presented. It has been established that graphite domains have nanometer sizes in all three dimensions, and consist of about three turbostratically stacked nanographenes. Such multilayer nanographene clusters (nanographites) are structural blocks of ACF and they are separated from each other by the micropores and/or sp³-amorphous carbon phase. From the data of magnetic methods of investigations, it follows that the density of states at the Fermi energy in nanographites is significantly larger than the value of that parameter in macroscopic graphite, which testifies the existence of edge π-electron states in them.

Abstract: Conformal metasurfaces are even more diffused in different fields from optics to electromagnetics. Advanced applications, as making object invisible to incident fields also known as cloaking, require high precision realizations, since the resonant answer of the system is very sensitive to geometry details. Practical realizations are provocative, since material characteristics and mechanical restrictions should also be considered. Multi- and inter-disciplinary interactions are mandatory to overcome such technological challenges. Due to its excellent esthetic characteristics, good physical and mechanical properties, Aluminium is widely used for deposition on different substrates: physical and chemical vapor depositions are very suitable for micro-metallization process and for the realization of multilayered structures. This paper presents some results about the behavior of a cylindrical-shape system realized by Al films deposition on flexible, polymeric organosilicon substrate.

Abstract: To examine perspectives of nanoparticle films in the role of active elements in strain sensors, morphological and electrical properties of self-assembled Au nanoparticle monolayer prepared by modified Langmuir-Schaefer technique onto supporting Mylar foil were studied under elongation. Along the probing of electrical response (characterized by the gauge factor of about 60), the small-angle x-ray scattering (SAXS) characterization assessed an average interparticle distance change, which was shown to vary proportionally to the substrate elongation. The approach allowed to unambiguously address the mechanism of the deformation-resistivity transduction.