Construction and test of low cost X-ray tomography scanner for physical-chemical analysis and nondestructive inspections

X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe the development of a low cost micro-CT X-ray scanner that is being developed for nondestructive testing. This tomograph operates using a microfocus X-ray source and contains a silicon photodiode as detectors. The performance of the system, by its spatial resolution, has been estimated through its Modulation Transfer Function - MTF and the obtained value at 10% of MTF is 661 μm. It was built as a general purpose nondestructive testing device. © 2009 American Institute of Physics.

Integrated X-ray crystallography, optical and computational methods in studies of structure and luminescence of new synthesized complexes of lanthanides with ligands derived from 2,6-diformylpyridine

The reaction of 2,6-diformylpyridine-bis(benzoylhydrazone) [dfpbbh] and 2,6-diformylpyridine-bis(4-phenylsemicarbazone) [dfpbpsc] with lanthanides salts yielded the new chelates complexes [Eu(dfpbpsc-H +) 2]NO 3 (1), [Dy(fbhmp) 2][Dy(dfpbbh-2H +) 2]·2EtOH·2H 2O (fbhmp = 2-formylbenzoylhydrazone-6-methoxide-pyridine; Ph = phenyl; Py = pyridine; Et = ethyl) and [Er 2(dfpbbh-2H +) 2(μ-NO 3)(H 2O) 2(OH)]·H 2O. X-ray diffraction analysis was employed for the structural characterization of the three chelate complexes. In the case of complex 1, optical, synthetic and computational methods were also exploited for ground state structure determinations and triplet energy level of the ligand and HOMO-LUMO calculations, as well as for a detailed study of its luminescence properties. © 2010 Elsevier Ltd. All rights reserved.

Fe K-edge X-ray absorption spectroscopy study of Pb(Fe2/3W 1/3)O3-PbTiO3 multiferroic ceramics

The present paper is a comprehensive study concerning Fe K-edge X-ray absorption spectroscopy (XAS) measurements, which were performed to characterize the local structure of (1 - x)Pb(Fe2/3W1/3)O 3-xPbTiO3 samples as a function of temperature and PbTiO3 content. Results obtained by the fits of extended X-ray absorption fine structure consist with rhombohedral symmetry for Pb(Fe 2/3W1/3)O3 composition at temperatures lower than room temperature. This result is in apparent disagreement with X-ray and neutron diffraction characterization which have been reported. This apparent disagreement is related to the fact that XAS probes the short-range order, whereas X-ray diffraction provides structural information about the average structure. Moreover, as the PbTiO3 content increases, a disorder has been detected at local structure of the FeO6 octahedron. Analysis of X-ray absorption near edge structure spectra did not show modifications in intensity nor energy of transitions. © 2013 American Institute of Physics.

Monte Carlo simulation applied in total reflection X-ray fluorescence: Preliminary results

The X-ray Fluorescence (XRF) analysis is a technique for the qualitative and quantitative determination of chemical constituents in a sample. This method is based on detection of the characteristic radiation intensities emitted by the elements of the sample, when properly excited. A variant of this technique is the Total Reflection X-ray Fluorescence (TXRF) that utilizes electromagnetic radiation as excitation source. In total reflection of X-ray, the angle of refraction of the incident beam tends to zero and the refracted beam is tangent to the sample support interface. Thus, there is a minimum angle of incidence at which no refracted beam exists and all incident radiation undergoes total reflection. In this study, we evaluated the influence of the energy variation of the beam of incident x-rays, using the MCNPX code (Monte Carlo NParticle) based on Monte Carlo method. © 2013 AIP Publishing LLC.

Evaluation via multivariate techniques of scale factor variability in the rietveld method applied to quantitative phase analysis with X ray powder diffraction

ABSTRACT: The present work uses multivariate statistical analysis as a form of establishing the main sources of error in the Quantitative Phase Analysis (QPA) using the Rietveld method. The quantitative determination of crystalline phases using x ray powder diffraction is a complex measurement process whose results are influenced by several factors. Ternary mixtures of Al2O3, MgO and NiO were prepared under controlled conditions and the diffractions were obtained using the Bragg-Brentano geometric arrangement. It was possible to establish four sources of critical variations: the experimental absorption and the scale factor of NiO, which is the phase with the greatest linear absorption coefficient of the ternary mixture; the instrumental characteristics represented by mechanical errors of the goniometer and sample displacement; the other two phases (Al2O3 and MgO); and the temperature and relative humidity of the air in the laboratory. The error sources excessively impair the QPA with the Rietveld method. Therefore it becomes necessary to control them during the measurement procedure.

Multivariate curve resolution analysis applied to time-resolved synchrotron X-ray Absorption Spectroscopy monitoring of the activation of copper alumina catalyst

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Crystallization and preliminary X-ray crystallographic analysis of importin-alpha from Neurospora crassa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Limits of Visual Detection for Finasteride Polymorphs in Prepared Binary Mixtures: Analysis by X-ray Powder Diffraction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Quantitative phase analysis from X-ray diffraction in Y-TZP dental ceramics: A critical evaluation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crystallization and preliminary X-ray diffraction analysis of a novel sphingomyelinase D from Loxosceles gaucho venom

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of femur of orchiectomized guinea pigs by bone densitometry using dual-energy x-ray absortiometry (DXA) and mechanical testing

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Copper ore type definition from Sossego Mine using X-ray diffraction and cluster analysis technique

This paper presents the classification of 110 copper ore samples from Sossego Mine, based on X-ray diffraction and cluster analysis. The comparison based on the position and the intensity of the diffracted peaks allowed the distinction of seven ore types, whose differences refer to the proportion of major minerals: quartz, feldspar, actinolite, iron oxides, mica and chlorite. There was a strong correlation between the grouping and the location of the samples in Sequeirinho and Sossego orebodies. This relationship is due to different types and intensities of hydrothermal alteration prevailing in each body, which reflect the mineralogical composition and thus the X-ray diffractograms of samples.

Preparation and characterization of chloroaluminum phthalocyanine-loaded solid lipid nanoparticles by thermal analysis and powder X-ray diffraction techniques

Solid lipid nanoparticles (SLN) without drug and SLN loaded with chloroaluminum phthalocyanine (AlClPc) were prepared by solvent diffusion method in aqueous system and characterized by thermal analyses and X-ray diffraction (XRD) in this study. Determination of particle size, zeta potential (ZP), and encapsulation efficiency were also evaluated. SLN containing AlClPc of nanometer size with high encapsulation efficiency and ZP were obtained. The results indicated that the size of SLN loaded with AlClPc is larger than that of the inert particle, but ZP is not changed significantly with incorporation of the drug. In differential scanning calorimetry (DSC) curves, it was observed that the melting point of stearic acid (SA) isolated and in SLN occurred at 55 and 64 degrees C, respectively, suggesting the presence of different polymorphs. DSC also shows that the crystallinity state of SLN was much less than that of SA isolated. The incorporation of drug in SLN may have been favored by this lower crystallinity degree of the samples. XRD techniques corroborated with the thermal analytic techniques, suggesting the polymorphic modifications of stearic acid.

Direct Determination of Sugar Cane Quality Parameters by X-ray Spectrometry and Multivariate Analysis

Current methods for quality control of sugar cane are performed in extracted juice using several methodologies, often requiring appreciable time and chemicals (eventually toxic), making the methods not green and expensive. The present study proposes the use of X-ray spectrometry together with chemometric methods as an innovative and alternative technique for determining sugar cane quality parameters, specifically sucrose concentration, POL, and fiber content. Measurements in stem, leaf, and juice were performed, and those applied directly in stem provided the best results. Prediction models for sugar cane stem determinations with a single 60 s irradiation using portable X-ray fluorescence equipment allows estimating the % sucrose, % fiber, and POL simultaneously. Average relative deviations in the prediction step of around 8% are acceptable if considering that field measurements were done. These results may indicate the best period to cut a particular crop as well as for evaluating the quality of sugar cane for the sugar and alcohol industries.

Probing the cosmic distance-duality relation with the Sunyaev-Zel'dovich effect, X-ray observations and supernovae Ia

Context. The angular diameter distances toward galaxy clusters can be determined with measurements of Sunyaev-Zel'dovich effect and X-ray surface brightness combined with the validity of the distance-duality relation, D-L(z)(1 + z)(2)/D-A(z) = 1, where D-L(z) and D-A(z) are, respectively, the luminosity and angular diameter distances. This combination enables us to probe galaxy cluster physics or even to test the validity of the distance-duality relation itself. Aims. We explore these possibilities based on two different, but complementary approaches. Firstly, in order to constrain the possible galaxy cluster morphologies, the validity of the distance-duality relation (DD relation) is assumed in the Lambda CDM framework (WMAP7). Secondly, by adopting a cosmological-model-independent test, we directly confront the angular diameters from galaxy clusters with two supernovae Ia (SNe Ia) subsamples (carefully chosen to coincide with the cluster positions). The influence of the different SNe Ia light-curve fitters in the previous analysis are also discussed. Methods. We assumed that eta is a function of the redshift parametrized by two different relations: eta(z) = 1 +eta(0)z, and eta(z) = 1 + eta(0)z/(1 + z), where eta(0) is a constant parameter quantifying the possible departure from the strict validity of the DD relation. In order to determine the probability density function (PDF) of eta(0), we considered the angular diameter distances from galaxy clusters recently studied by two different groups by assuming elliptical and spherical isothermal beta models and spherical non-isothermal beta model. The strict validity of the DD relation will occur only if the maximum value of eta(0) PDF is centered on eta(0) = 0. Results. For both approaches we find that the elliptical beta model agrees with the distance-duality relation, whereas the non-isothermal spherical description is, in the best scenario, only marginally compatible. We find that the two-light curve fitters (SALT2 and MLCS2K2) present a statistically significant conflict, and a joint analysis involving the different approaches suggests that clusters are endowed with an elliptical geometry as previously assumed. Conclusions. The statistical analysis presented here provides new evidence that the true geometry of clusters is elliptical. In principle, it is remarkable that a local property such as the geometry of galaxy clusters might be constrained by a global argument like the one provided by the cosmological distance-duality relation.