The Preparation and Contact Drying Performance of Encapsulated Microspherical Composite Sorbents Based on Fly Ash Cenospheres.

Sorption technologies are essential for various industries because they provide product quality and process efficiency. New encapsulated microspherical composite sorbents have been developed for resource-saving contact drying of thermolabile materials, particularly grain and seeds of crops. Magnesium sulfate, known for its high water capacity, fast sorption kinetics, and easy regeneration, was used as an active moisture sorption component.

Thermokinetic Study of Aluminum-Induced Crystallization of a-Si: The Effect of Al Layer Thickness.

The effect of the aluminum layer on the kinetics and mechanism of aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) in (Al/a-Si) multilayered films was studied using a complex of in situ methods (simultaneous thermal analysis, transmission electron microscopy, electron diffraction, and four-point probe resistance measurement) and ex situ methods (X-ray diffraction and optical microscopy). An increase in the thickness of the aluminum layer from 10 to 80 nm was found to result in a decrease in the value of the apparent activation energy E of silicon crystallization from 137 to 117 kJ/mol (as estimated by the Kissinger method) as well as an increase in the crystallization heat from 12.3 to 16.

Characterization of Silicate Glass/Mullite Composites Based on Coal Fly Ash Cenospheres as Effective Gas Separation Membranes.

Membrane technology is a promising method for gas separation. Due to its low energy consumption, environmental safety, and ease of operation, membrane separation has a distinct advantage over the cryogenic distillation conventionally used to capture light inert gases. For efficient gas recovery and purification, membrane materials should be highly selective, highly permeable, thermally stable, and low-cost.

A Challenge toward Novel Quaternary Sulfides SrLnCuS (Ln = La, Nd, Tm): Unraveling Synthetic Pathways, Structures and Properties.

We report on the novel heterometallic quaternary sulfides SrLnCuS (Ln = La, Nd, Tm), obtained as both single crystals and powdered samples. The structures of both the single crystal and powdered samples of SrLaCuS and SrNdCuS belong to the orthorhombic space group but are of different structural types, while both samples of SrTmCuS crystallize in the orthorhombic space group with the structural type KZrCuS. Three-dimensional crystal structures of SrLaCuS and SrNdCuS are formed from the (Sr/Ln)S capped trigonal prisms and CuS tetrahedra.

Quaternary Selenides EuLnCuSe: Synthesis, Structures, Properties and In Silico Studies.

In this work, we report on the synthesis, in-depth crystal structure studies as well as optical and magnetic properties of newly synthesized heterometallic quaternary selenides of the EuLnCuSe composition. Crystal structures of the obtained compounds were refined by the derivative difference minimization (DDM) method from the powder X-ray diffraction data. The structures are found to belong to orthorhombic space groups (structure type BaMnS for EuLaCuSe and structure type EuCuS for EuLnCuSe, where Ln = Sm, Gd, Tb, Dy, Ho and Y) and (structure type KZrCuS for EuLnCuSe, where Ln = Tm, Yb and Lu).

Carbon Double Coated FeO@C@C Nanoparticles: Morphology Features, Magnetic Properties, Dye Adsorption.

This work is devoted to the study of magnetic FeO nanoparticles doubly coated with carbon. First, FeO@C nanoparticles were synthesized by thermal decomposition. Then these synthesized nanoparticles, 20-30 nm in size were processed in a solution of glucose at 200 °C during 12 h, which led to an unexpected phenomenon-the nanoparticles self-assembled into large conglomerates of a regular shape of about 300 nm in size.

Magnetic Fractions of PM, PM, and PM from Coal Fly Ash as Environmental Pollutants.

Characterization of magnetic particulate matter (PM) in coal fly ashes is critical to assessing the health risks associated with industrial coal combustion and for future applications of fine fractions that will minimize solid waste pollution. In this study, magnetic narrow fractions of fine ferrospheres related to environmentally hazardous PM, PM, and PM were for the first time separated from fly ash produced during combustion of Ekibastuz coal. It was determined that the average diameter of globules in narrow fractions is 1, 2, 3, and 7 μm.

Effect of Multiplicity Fluctuation in Cobalt Ions on Crystal Structure, Magnetic and Electrical Properties of NdCoO and SmCoO.

The structural, magnetic, electrical, and dilatation properties of the rare-earth NdCoO and SmCoO cobaltites were investigated. Their comparative analysis was carried out and the effect of multiplicity fluctuations on physical properties of the studied cobaltites was considered. Correlations between the spin state change of cobalt ions and the temperature dependence anomalies of the lattice parameters, magnetic susceptibility, volume thermal expansion coefficient, and electrical resistance have been revealed.

Crystal structure variations in the series SrLnCuS (Ln = La, Pr, Sm, Gd, Er and Lu).

The crystal structures of the complex sulfides SrLnCuS (Ln = Sm, Gd, Er and Lu) have been determined and refined using powder X-ray diffraction. The crystals are found to be orthorhombic, with the structure type changing consecutively in the order BaLaCuS → EuCuS → KZrCuS as the Ln ionic radius decreases in the order La/Pr → Sm/Gd → Er/Lu. Variations of the structure parameters along the series of compounds studied are analyzed, and an effect caused by crystallochemical contraction on the stabilization of the respective structure types is demonstrated.

Accurate unrestrained DDM refinement of crystal structures from highly distorted and low-resolution powder diffraction data.

The structure of benzene:ethane co-crystal at 90 K is refined with anisotropic displacement parameters without geometric restraints from high-resolution synchrotron X-ray powder diffraction (XRPD) data using the derivative difference method (DDM) with properly chosen weighting schemes. The average C-C bond precision achieved is 0.005 Å and the H-atom positions in ethane are refined independently.

Methane oxidation over A-site ordered and disordered Sr(0.8)Gd(0.2)CoO(3-δ) perovskites.

A tetragonal phase Sr0.8Gd0.2CoO3-δ with ordered Gd(3+)/Sr(2+) ions and oxygen vacancy sites is found to be about five times less active in the reaction of methane combustion than a quenched cubic perovskite phase with randomly distributed (disordered) Gd(3+)/Sr(2+) ions over the A-sites of the crystal lattice.

Complete crystal structure of decafluorocyclohex-1-ene at 4.2 K from original neutron diffraction data.

The crystal structure model of decafluorocyclohex-1-ene at 4.2 K derived from simulated powder diffraction data and solid-state energy minimization [Smrčok et al. (2013).

Structure and sorption properties of a zeolite-templated carbon with the EMT structure type.

An ordered microporous carbon material was prepared by the nanocasting process using the EMC-2 zeolite (EMT structure type) as a hard template. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed long-range ordering in the material that resulted from the negative replication of the host template. The carbon porous network replicating the zeolite structure was modeled by overlapped spherical voids with diameters determined from the XRD pattern that displayed up to six distinct peaks.

Diffraction analysis of mesostructured mesoporous materials.

Ordered mesostructured mesoporous materials, combining nano-organization with atomic disorder, are both attractive and challenging objects of investigation by X-ray and neutron diffraction. The development of diffraction mesostructure analysis methods and their applications in studies on structural characterization, formation processes and physisorption phenomena in these advanced materials are summarized in this tutorial review. The focus here is on the techniques that allow extracting mesostructure parameters and peculiarities of density distribution in the materials from the Bragg reflection positions and intensities.

Revision of the Mg(ClO4)2·4H2O crystal structure.

A revision is presented of the restrained Rietveld analysis of the crystal structure of magnesium perchlorate tetrahydrate, Mg(ClO(4))(2)·4H(2)O, recently published by Robertson & Bish [(2010), Acta Cryst. B 66, 579-584]. The actual symmetry of the material is shown to be C2/m.

Formation of bimetallic Au-Pd and Au-Pt nanoparticles under hydrothermal conditions and microwave irradiation.

The reduction of chlorocomplexes of gold(III) from muriatic solutions by nanocrystal powders of palladium and platinum at 110 and 130 °C under hydrothermal conditions and the action of microwave irradiation has been investigated. The structure and composition of the solid phase have been characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and chemical methods. Bimetallic particles with a core-shell structure have been revealed.

Sonochemical coating of paper by microbiocidal silver nanoparticles.

Colloidal silver has gained wide acceptance as an antimicrobial agent, and various substrates coated with nanosilver such as fabrics, plastics, and metal have been shown to develop antimicrobial properties. Here, a simple method to develop coating of colloidal silver on paper using ultrasonic radiation is presented, and the coatings are characterized using X-ray diffraction (XRD), high resolution scanning electron microscope (HRSEM), and thermogravimetry (TGA) measurements. Depending on the variables such as precursor concentrations and ultrasonication time, uniform coatings ranging from 90 to 150 nm in thickness have been achieved.

Synthesis of ZnO and Zn nanoparticles in microwave plasma and their deposition on glass slides.

This work represents a new method to synthesis of ZnO and/or Zn nanoparticles by means of microwave plasma whose electrons are the reducing agents. Glass quadratic slides sized 2.5 x 2.

Highly Luminescent Zn(x)Cd(1-x)Se/C Core/Shell Nanocrystals: Large Scale Synthesis, Structural and Cathodoluminescence Studies.

Zn(x)Cd(1-x)Se/C core/shell nanocrystals with 31-39 nm semiconducting core and 11-25 nm carbon shell were synthesized from solid state precursors in large scale amounts. A mixture of spherical and tripod nanostructures were obtained only in the one-step reaction (ZC3), where the Zn- and Cd-precursors were reacted simultaneously, rather than in the two step reactions (ZC1 and ZC2), where largely spherical nanostructures were observed. Rietveld analysis of the X-ray diffraction patterns of the samples prepared in three different ways, all under their autogenic pressure, reveal varying compositions of the Zn(x)Cd(1-x)Se nanocrystal core, where the cubic phases with higher Zn content were dominant compared to the hexagonal phases.

Direct observation of stacking faults and pore connections in ordered cage-type mesoporous silica FDU-12 by electron tomography.

The porous structure and the periodic array of cavities in ordered mesoporous materials with large, three-dimensionally arranged and interconnected pores is thoroughly described by combining electron tomography, small-angle X-ray diffraction, and nitrogen sorption techniques. We used the ability of the electron tomography to provide local three-dimensional information of a nano-object and compared the results to those of the other characterization techniques which furnish global information. We showed thus that the face-centered cubic (fcc) structure usually assigned to the FDU-12 materials is in fact an intergrowth of cubic and hexagonal close-packing structures.

Improvement of the Kruk-Jaroniec-Sayari method for pore size analysis of ordered silicas with cylindrical mesopores.

In this work, the X-ray diffraction structure modeling was employed for analysis of hexagonally ordered large-pore silicas, SBA-15, to determine their pore width independently of adsorption measurements. Nitrogen adsorption isotherms were used to evaluate the relative pressure of capillary condensation in cylindrical mesopores of these materials. This approach allowed us to extend the original Kruk-Jaroniec-Sayari (KJS) relation (Langmuir 1997, 13, 6267) between the pore width and capillary condensation pressure up to 10 nm instead of previously established range from 2 to 6.

X-ray diffraction structure analysis of MCM-48 mesoporous silica.

The structure of MCM-48 mesoporous silicate materials has been fully characterized from X-ray diffraction data by applying recently developed methods of mesostructure analysis and full-profile refinement. The pore wall thickness of both as-made and calcined MCM-48 was determined with high precision to be 8.0(1) Angstrom.

Assessment of ordered and complementary pore volumes in polymer-templated mesoporous silicas and organosilicas.

A method to determine the volumes of ordered mesopores and complementary small pores in polymer-templated ordered mesoporous silicas and organosilicas is proposed on the basis of the existing relation between the pore width and unit cell values obtained by the XRD structure modeling and the adsorption pore volume.

Powder diffraction crystal structure analysis using derivative difference minimization: example of the potassium salt of 1-(tetrazol-5-yl)-2-nitroguanidine.

The crystal structure of the potassium salt of 1-(tetrazol-5-yl)-2-nitroguanidine [K(C2H3N8O2)] was solved and refined from X-ray powder diffraction data by applying the derivative difference minimization (DDM) method. The compound is of interest as an energetic substance. The structure model was found from a Patterson search.

Transformation of highly ordered large pore silica mesophases (Fm3m, Im3m and p6mm) in a ternary triblock copolymer-butanol-water system.

Exceptional control of the phase behavior of highly ordered large pore mesostructured silica (with the choice of Fm3m, Im3m or p6mm symmetry) is achieved using a triblock copolymer (EO(106)PO(70)EO(106)) and butanol at low acid concentrations.