X-ray Mapping Research Articles

Effects of tungsten and cobalt concentration on microstructure and anticorrosive property of cobalt-tungsten alloys

The replacement of chrome coatings for materials that maintain the same properties has become the Co-W alloy relevant. In this context, we proposed to evaluate the effects of the Co and W concentration in the electrolytic bath on the faradaic efficiency, morphology, and anticorrosive property of the Co-W alloy. The diffractograms indicated a tendency to amorphization when the W concentration increased from 0.1 to 0.3 M, and the faradaic efficiency achieved values close to 70%. Alloy surfaces demonstrated a homogeneous composition according to the energy-dispersive X-ray mapping. The increase of Co and W concentration promoted the formation of rounded structures and reduced the space between the microcracks. Moreover, the high concentration of these promoted greater corrosion resistance with a corrosion current density of 1.83 µA cm−2.

BiVO4/WO3 nano-composite: characterization and designing the experiments in photodegradation of sulfasalazine.

A BiVO4-WO3 nano-composite (NC) was hydrothermally prepared and characterized by different techniques including X-ray diffraction (XRD), scanning electron microscope equipped with an energy-dispersive X-ray (EDX) analyzer, X-ray mapping, UV-Vis reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The average crystallite size of 8.5nm was estimated for the composite by the Williamson-Hall equation. The band gap energies of 2.46, 3.02, and 2.95eV were obtained for the direct electronic transitions of BiVO4, WO3, and the composite, respectively. The point of zero charges (pHpzc) of the composite was also estimated at 5. The composite was then used in the photodegradation of sulfasalazine (SSZ). When the moles of WO3 was four times greater than BiVO4, the best photocatalytic activity and the lowest PL intensity were obtained. The simultaneous effects of the experimental variables on the boosted photocatalytic activity of the composite (to the single semiconductors) were studied by the response surface methodology (RSM). A significant quadratic model was confirmed for processing the data based on the F value of a model F value of 63.55 > F0.05, 14, 13 = 2.55. This was also confirmed by LOF F value of 2.56 < F0.05, 10, 3 = 8.79. Besides, the multiple correlation coefficients R2 (R2 = 0.9856), adjusted R2 (adj-R2 = 0.9701), and predicted R2 (pred-R2 = 0.9098) confirm the goodness of the model. The optimal run included CSSZ 9mg/L, pH4, 40min irradiation time, and 0.8g/L of the composite under the visible light irradiation.

Efficient photocatalysis of organic dyes under simulated sunlight irradiation by a novel magnetic CuFe2O4@porphyrin nanofiber hybrid material fabricated via self-assembly

The main aim of this study was to synthesize an innovative magnetic CuFe2O4@porphyrin nanofiber hybrid material via one-step re-precipitation self-assembly of freebase-tetracarboxy-porphyrin (TCPP), in the presence of CuFe2O4 nanoparticles. The resultant hybrid materials were thoroughly characterized using scanning electron microscopy, energy-dispersive X-ray mapping, X-ray diffractometry, and Fourier-transform infrared, and UV–vis spectroscopy. Results showed well-integration of CuFe2O4 nanoparticles into TCPP nanofiber network, with the average size of CuFe2O4 being less than 100 nm and diameter and length of TCPP aggregate being approximately 20 nm and several µm, respectively. The as-prepared hybrid material possessed strong magnetic properties with a saturated magnetization value of approximately 25 emu/g. This photocatalyst was highly efficient in the removal of rhodamine B (RhB) dye, with the rate constant reaching 2.1 × 10−2 min−1. This paper describes in detail a plausible photocatalytic mechanism for RhB removal by CuFe2O4@porphyrin nanofiber hybrid material.

Bioactive glass scaffold architectures regulate patterning of bone regeneration in vivo

The architecture of bone scaffolds, such as pore dimensions, connectivity and orientation can regulate osteogenic defect repair, as can their rate of degradation. Synthetic bone grafts have historically been developed with foam structures to mimic trabecular bone. Now, Additive Manufacturing techniques enable production of open and regular pore architectures with improved compressive strengths. Here, we compare two types of bioactive glass scaffolds, made of the highly biodegradable ICIE16 composition, with distinctively different architectures but matched interconnect sizes (~150 µm), produced via two different techniques: gel-cast foaming and direct ink writing. A rabbit lateral femoral defect model was used to compare the effect of their architecture on in vivo bone regeneration, relative to a defect only control group, after 4 and 10 weeks of implantation. 3D X-ray microcomputed tomography (micro-CT), correlated to histology and back-scatter electron microscopy (BS-SEM) permitted quantitative evaluation of new bone ingrowth and degradation of the scaffolds. Both foam and printed scaffolds showed equal or higher bone ingrowth compared to the control group. After 4 weeks, the foam group showed the highest osteogenesis, with 51% more bone ingrowth than the defect only controls, but after 10 weeks the defect treated with the printed scaffold had the most bone ingrowth (40% more than the empty defect). Energy dispersive X-ray (EDS) mapping revealed degradation of the glass and calcium-phosphate deposition. The foam group showed more rapid degradation than the printed group, due to higher total porosity (even though interconnected pore size was equivalent). The foam scaffold appeared to allow rapid bone ingrowth and cancellous bone formation, whereas the printed scaffold seemed to provoke cortical-like bone formation, while remaining in place for longer than the 10 week study. While the foam's concave architectures promote initial bone ingrowth, the higher strength open pore channels of the printed scaffolds are beneficial for scaffolds made of highly degradable bioactive glasses.

Uncovering Magnetic Turbulence in Young Supernova Remnants with Polarized X-Ray Imaging

Abstract Observations of young supernova remnants (SNRs) in X-rays and γ-rays have provided conclusive evidence for particle acceleration to at least TeV energies. Analysis of high-spatial-resolution X-ray maps of young SNRs has indicated that the particle acceleration process is accompanied by strong nonadiabatic amplification of magnetic fields. If Fermi acceleration is the mechanism producing the energetic cosmic rays (CRs), the amplified magnetic field must be turbulent, and CR-driven instabilities are among the most probable mechanisms for converting the shock ram pressure into magnetic turbulence. The development and evolution of strong magnetic turbulence in collisionless plasmas forming SNR shells are complicated phenomena which include the amplification of magnetic modes, anisotropic mode transformations at shocks, as well as the nonlinear physics of turbulent cascades. Polarized X-ray synchrotron radiation from ultrarelativistic electrons accelerated in the SNR shock is produced in a thin layer immediately behind the shock and is not subject to the Faraday depolarization effect. These factors open up possibilities to study some properties of magnetic turbulence, and here we present polarized X-ray synchrotron maps of SNR shells assuming different models of magnetic turbulence cascades. It is shown that different models of anisotropic turbulence can be distinguished by measuring the predominant polarization angle direction. We discuss the detection of these features in Tycho’s SNR with the coming generation of X-ray polarimeters such as the Imaging X-ray Polarimetry Explorer.

FEGSEM X-Ray Mapping System with Multiple SDDs for Quantitative X-Ray Mapping and Imaging

FEGSEM X-Ray Mapping System with Multiple SDDs for Quantitative X-Ray Mapping and Imaging

ColorSEM: Livetime Quantitative X-ray Mapping in an Integrated EDS Workflow

ColorSEM: Livetime Quantitative X-ray Mapping in an Integrated EDS Workflow

X-ray Mapping Characterisation of Hybrid Alkaline Cement Discolouration Area

X-ray Mapping Characterisation of Hybrid Alkaline Cement Discolouration Area

Structural interpretation of cryo-EM image reconstructions

The productivity of single-particle cryo-EM as a structure determination method has rapidly increased as many novel biological structures are being elucidated. The ultimate result of the cryo-EM experiment is an atomic model that should faithfully represent the computed image reconstruction. Although the principal approach of atomic model building and refinement from maps resembles that of the X-ray crystallographic methods, there are important differences due to the unique properties resulting from the 3D image reconstructions. In this review, we discuss the practiced work-flow from the cryo-EM image reconstruction to the atomic model. We give an overview of (i) resolution determination methods in cryo-EM including local and directional resolution variation, (ii) cryo-EM map contrast optimization including complementary map types that can help in identifying ambiguous density features, (iii) atomic model building and (iv) refinement in various resolution regimes including (v) their validation and (vi) discuss differences between X-ray and cryo-EM maps. Based on the methods originally developed for X-ray crystallography, the path from 3D image reconstruction to atomic coordinates has become an integral and important part of the cryo-EM structure determination work-flow that routinely delivers atomic models.

Desalination of dye utilizing carboxylated TiO2/calcium alginate hydrogel nanofiltration membrane with high salt permeation

In order to recover dyes from textile wastewater, a self-supported carboxylated titanium dioxide/calcium alginate (TiO2-COOH/CaAlg) hydrogel nanofiltration membrane was prepared using TiO2-COOH as the reinforcing agent. The Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX) mapping scanning spectra were employed to characterize the distribution of TiO2-COOH nanoparticles on the membrane surface. The pore size distribution, zeta potential and mechanical performance of the membrane were evaluated. The rejections for single dye solutions, salt solutions and dye/salt mixture solutions were also examined. The results indicate that the TiO2-COOH nanoparticles are dispersed uniformly on the membrane surface. Compared to CaAlg membrane, the tensile strength of 20 wt% TiO2-COOH/CaAlg membrane is enhanced by 328%. At the operating pressure of 0.1 MPa, the rejection ratios of 20 wt% TiO2-COOH/CaAlg membrane for 100 mg/L Brilliant blue G250, Direct black 38 and Congo red are 98.4%, 96.8% and 95.9% respectively, and the permeate flux is about 14.1 L·m−2·h−1. Meanwhile, this membrane possesses the low rejection ratios for inorganic salts (16.1%, 15.6%, 12.3% and 9.0% for MgSO4, Na2SO4, MgCl2 and NaCl, respectively), excellent dye anti-fouling property and good stability in the long-term filtration for dye/salt mixture solution.

A new poly carboxylic catex polymer-gold nanoparticles modified electrode for determination of paraquat by voltammetry method

A new catex polymeric-gold nanoparticle composite modified electrode for the determination of paraquat (PQ) in various samples is introduced. Fabrication of the electrode is based on casting a poly carboxylic polymer on a glassy carbon electrode, which was prepared separately in an electrochemical system; after which electrodeposition of the gold particles on the surface of electrode took place. The morphology of the electrode surface was investigated by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometry (EDS) and mapping. Chemical structure of prepared composite was studied by differential scanning calorimetry (DSC), Fourier-transform infrared spectrometry (FTIR), and H NMR spectrometry. The obtained results show that the prepared polymer is a weak catex with carboxylate groups. The presence of the gold particles in the composite enhanced the sensitivity of the electrode for the determination of paraqaut. The application of this electrode for determination of paraquat is based on the redox property of paraquat. The fabricated electrode shows a wide range of linearity (1.9 × 10−8−7.8 × 10-7 mol L-1) and LOQ (7.78 × 10-10). The mean, standard deviation and RSD for five repetitive determinations of paraquat (3.20 × 10-7 mol L-1) are 3.15 × 10-7 mol L-1, ±1.40 × 10−8 mol L-1 and 4.28 % respectively. This electrode was successfully applied for determination of paraquat in natural waters and soils. The obtained results were compared with the results of standard methods. The characteristic parameters of the offered method were compared with other electrochemical methods.

Compression behaviour of granules produced via twin-screw melt granulation: Effect of initial particle size on granulation efficiency

This study focuses on the impact of initial particle size on the tabletability and the deformation behaviour (i.e. plasticity) of granules produced by twin-screw melt granulation (TSMG). As model substances, three different grades of anhydrous dicalcium phosphate (aDCP) were melt-granulated with polyethylene glycol 6000 (PEG) using a twin-screw granulator. Compaction performance of the granules and the corresponding physical mixtures (PM) was evaluated by in-die and out-of-die compaction analysis. A major impact on granules deformation behaviour was found for the relation of the specific surface area of the filler material to the binder content. A relative yield pressure (YP) was introduced to describe the enhancement in plastic deformation behaviour, defined as the plasticity performance factor (PPF). Furthermore, a modified Kawakita model was used to describe the granulation efficiency, compared to a calculated physical mixture model. Granules under investigation showed an increased plastic deformation, enhanced tabletability and reduced elastic recovery (ER). The binder was shown to be finely distributed and to fill the voids between the aDCP particles (image analysis of the carbon energy dispersive X-ray maps). A small initial particle size of filler material (DI-CAFOS® A7 and A12) was more efficient than a larger particle size (DI-CAFOS® A60). A very low particle size (DI-CAFOS® A7) required the addition of 1% (w/w) colloidal silicon dioxide to enable feeding of the material into the granulator. Moreover, due to the larger surface area of these particles, a higher amount of binder was necessary to achieve a low PPF and a high tensile strength (TS).

Green Synthesis of CuO nanoparticles via Plectranthus amboinicus leaves extract with its characterization on structural, morphological, and biological properties

Synthetic synthesis of nanoparticles is harmful to human and environment due to pollution. The use of harmful chemicals in synthetic method has avoided in the biosynthesis. To overcome the hurdles in synthesis of nanoparticles, the biogenic synthesis of CuO nanoparticles has been done with Plectranthus amboinicus leaf extracts. The biosynthesis provides the enhanced efficiency compared to synthetic methods. It establishes the environmentally friendly and pollution-free approach. The powder X-ray diffraction (XRD) pattern exhibited a crystalline nature with the crystallite size in 20–35 nm. The Fourier-Transform InfraRed (FTIR) spectrum explicated the Cu and O metal oxide bonds. The UV–visible analysis emphasized the stability of CuO nanoparticles with the inference of the Surface Plasmon Resonance band at 398 nm. The photoluminescence study displayed the bluish–green emission nature peak at 491 nm. The particle size analyzer manifested the synthesized CuO nanoparticles majority in 5–40 nm. The field-emission scanning electron micrographs (FESEM) and high-resolution transmission electron micrographs (HRTEM) exposed the spherical, circular-shaped nanoparticles with size in 5–30 nm range. The energy dispersive X-ray diffraction (EDAX) spectrum and mapping proved the CuO nanoparticles formation. The antimicrobial activity reported the potent nature of formed CuO nanoparticles on bacteria and fungi. The antioxidant activity identified the effective free-radical scavenging activity nature at 95% in 80 μg/mL and IC50 value at 40.10 μg/mL concentration. The anti-inflammatory activity assessed the efficient nature of CuO nanoparticles in protein denaturation of Egg albumin at 92% in 500 μg/mL and IC50 value at 243.08 μg/mL concentration. The anti-diabetic activity established the effective inhibition on α-Amylase at 94% in 500 μg/mL and IC50 value at 317.19 μg/mL concentration. The anti-larvicidal activity manifested the potent inhibition on Anopheles subpictus mosquito larvae within 24 h in 100 ppm concentration and which exhibited low LC50 value.

Low temperature synthesis of highly pure cordierite materials by spark plasma sintering nano-oxide powders

The development of cordierite ceramics, using traditional materials and conventional methods, remains a key challenge because of the high and narrow sintering temperature range. In this work, single-phase cordierite ceramics were produced by spark plasma sintering nano-oxide powders, at low temperatures. A starting mixture of Al2O3, SiO2, and MgO nano-powders with the composition of stoichiometric cordierite was first sonicated, then, sintered in the temperature range 900–1200 °C. The raw powders, sonicated powder mixture, phase transformations, and fracture surface of sintered specimens were characterized by using an x-ray diffractometer and a field emission scanning electron microscope (FE-SEM). The hardness and fracture toughness were measured using the indentation technique. The influence of testing conditions, process parameters, characterization technique, and calculation method on hardness and fracture toughness was investigated. The FE-SEM images, x-ray maps, and EDS results revealed the homogeneity and stoichiometry of the sonicated powder and sintered samples. Highly pure α-cordierite was formed at 1150 °C. Samples that were sintered at 1150 and 1200 °C had bulk density of 2.58 g/cm3 (relative density of 100%), and maintained low average grain sizes of 28.68 and 34.95 nm, respectively. With the decrease in the temperature from 1200 to 1150 °C, the hardness of cordierite was slightly increased from 8.25 ± 0.158 to 8.46 ± 0.188 GPa, the fracture toughness was marginally improved from 2.2 ± 0.158 to 2.25 ± 0.238 MPa mm1/2, and the critical strain energy release rate was raised from 32.46 to 33.95 J/m2.

Astronomers unveil epic X-ray map of the Universe

Astronomers unveil epic X-ray map of the Universe

Microwave-Assisted Degradation of Paracetamol Drug Using Polythiophene-Sensitized Ag-Ag2O Heterogeneous Photocatalyst Derived from Plant Extract.

Ag–Ag2O nanoparticles were synthesized using Osmium sanctum plant extract. The nanoparticles were sensitized with polythiophene (PTh) and were characterized via scanning electron microscopy with energy dispersive X-ray and elemental mapping, transmission electron microscopy, X-ray diffraction (XRD), Fourier-transform infrared, and UV–vis spectroscopy analyses. The elemental mapping results revealed that the samples were composed of C, S, Ag, and O elements which were uniformly distributed in the nanohybrid. XRD analysis confirmed the crystalline nature of Ag–Ag2O nanoparticles, and the average particle size was found to be ranging between 36 and 40 nm. The optical band gap of Ag–Ag2O, PTh, and Ag–Ag2O/PTh was found to be 2.49, 1.1, 1.5, and 0.68 eV. The catalytic activity of Ag–Ag2O, PTh, and Ag–Ag2O/PTh was investigated by degrading paracetamol drug under microwave irradiation. Around 80% of degradation was achieved during 20 min irradiation. All degradation kinetics were fitted to the pseudo-first-order model. A probable degradation pathway for paracetamol degradation was proposed based on liquid chromatography mass spectrometry analysis of degraded fragments.

X-ray mapping in a scanning transmission electron microscope of InGaAs quantum dots with embedded fractional monolayers of aluminium

We investigate AlGaAs/GaAs superlattices as well as InGaAs/GaAs quantum wells and epitaxial quantum dots (QDs) where during the molecular beam epitaxy of InGaAs QDs the aluminium flux cell was opened briefly to incorporate fractional monolayers of Al into the InGaAs. We show that x-ray mapping with a large collection angle is capable of detecting 0.3–0.4 fractional Al monolayers with a resolution of just under 1 nm.

Studying ZIF-8 SURMOF Thin Films with a Langatate Crystal Microbalance: Single-Component Gas Adsorption Isotherms Measured at Elevated Temperatures and Pressures.

Characterizing the adsorption behavior of thin films at technical operation ranges is highly relevant in order to obtain appropriate experimental parameters, as well as to evaluate their possible integration in multiple applications. Nonetheless, gathering such experimental data is not a trivial task. In the case of metal-organic framework thin films, a particular interesting class of highly porous coatings, determination of adsorption isotherms at elevated temperatures and pressures is not commonly reported. Using a custom-designed langatate crystal microbalance following the principle for piezoelectric microbalances, but under harsher conditions, allowed us to present adsorption equilibrium measurements on a zeolitic imidazolate framework-8 (ZIF-8) surface-mounted metal-organic framework (SURMOF) thin film at temperatures between 35 and 100 °C and at a pressure range up to 10 bars. The layer-by-layer liquid-phase epitaxy approach was used to deposit ZIF-8 SURMOF thin films on langatate crystals. X-ray diffraction, infrared reflection absorption spectroscopy, and scanning electron microscopy combined with energy dispersive X-ray mapping were used to gather deeper information on the ZIF-8 thin film growth. Single-component isotherms were collected for different gases of practical interest, that is, CO2, C2H6, C2H4, C3H8, and C3H6. The measurements were obtained at 35, 50, 75, and 100 °C at a gauge pressure range up to 10 bars. The collected data showed a clear preferential adsorption of ethane over ethylene, whereas only a slight difference was found between propane and propylene. Additionally, the experimental data allowed for the determination of adsorption equilibrium constants and saturation loadings of the ZIF-8 material as a thin SURMOF film, which is of great importance for its integration in multiple applications, such as sensor devices or in membrane-based separation.

Microstructural and morphological development of eggshell powder and flyash-based geopolymers

The microstructural and morphological development of eggshell powder (ESP) and flyash (FA)-based geopolymer, prepared using alkaline liquid activator which is a mixture of sodium silicate and sodium hydroxide solution, was investigated. Various synthesis parameters for geopolymer were adopted to study the microstructural changes viz. precursor combination (70% ESP and 30% FA, 50% ESP and 50% FA, 30% ESP and 70% FA), activator ratio (Na2SiO3/NaOH–0.5, 1, and 2) and curing temperature (25, 50, and 80 °C). Morphological features and structural characterization of raw precursor materials were analyzed using an X-ray diffractometer (XRD), X-ray fluorescent (XRF), and Scanning electron microscopy (SEM) techniques. The process of geopolymerization was explicated using SEM with an energy dispersive X-ray spectrometer (SEM-EDX) and mapping. Increase in curing temperature altered the morphology of ESP-FA geopolymer. Curing of samples at the lower temperature resulted in unreacted precursor particles, whereas curing at the higher temperature resulted in the porous structure. Formation of Nan–(–Si–O–Al–O–Si–O–Si–O–)n– was confirmed in the optimum geopolymer as Si/Al and Na/Al ratios were found greater than 1. The co-existence of calcium silicate hydrate (C-S-H) gel with the main geopolymeric gel and its bonding with the remaining unreacted precursor particles have also been confirmed.

Synthesis of Functionalized Magnetic Nanoparticles, Their Conjugation with the Siderophore Feroxamine and its Evaluation for Bacteria Detection.

In the present work, the synthesis of magnetic nanoparticles, its coating with SiO2, followed by its amine functionalization with (3-aminopropyl)triethoxysilane (APTES) and its conjugation with deferoxamine, a siderophore recognized by Yersinia enterocolitica, using a succinyl moiety as a linker are described. Magnetic nanoparticles (MNP) of magnetite (Fe3O4) were prepared by solvothermal method and coated with SiO2 (MNP@SiO2) using the Stöber process followed by functionalization with APTES (MNP@SiO2@NH2). Then, feroxamine was conjugated with the MNP@SiO2@NH2 by carbodiimide coupling to give MNP@SiO2@NH2@Fa. The morphology and properties of the conjugate and intermediates were examined by eight different methods including powder X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive X-Ray (EDX) mapping. This exhaustive characterization confirmed the formation of the conjugate. Finally, in order to evaluate the capacity and specificity of the nanoparticles, they were tested in a capture bacteria assay using Yersinia enterocolitica.