Crystallite Size Distribution Research Articles

Screening of optimum composition of superparamagnetic nanocomposite microparticles modified with various layered double hydroxides for phosphorus removal

Superparamagnetic nanocomposite microparticles (NCMPs) modified with various layered double hydroxides (LDHs) (MgFe, MgAl and their Zr-doped equivalents) were investigated for phosphorus (P) removal. Screening of optimum composition was performed based on the P removal performance of NCMP@LDH particles as well as their magnetic separability in a flow-through column as a function of NCMP content (100–1000 mg) and stability as a function of LDH content (20–100%). The results showed that except for NCMP@MgFe-Zr, all the other particles exhibited a partial dissolution of LDH components at each of the examined LDH contents. However, NCMP@MgFe-Zr showed no dissolution up to a LDH content of 60% at all, whereas a partial dissolution occurred at a LDH content of 80 and 100%. Results of magnetic separability test revealed that the NCMP@MgFe-Zr composed of 500 mg magnetic particle (NCMP) and 60% LDH was separated from the solution with a separation efficiency of 96.9%, while lower NCMP contents resulted in lower separation efficiencies. P removal efficiency and specific removal capacity of the NCMP@MgFe-Zr with the optimized composition was found to be 18.5% and 53.1 mg/g, respectively. The crystal structure, chemical composition, surface morphology, crystallite size and particle size distribution, functional groups and magnetic properties of the NCMP and NCMP@MgFe-Zr particles were confirmed by various characterization analysis. The observed results clearly demonstrates that the NCMP@MgFe-Zr with the optimized composition remained stable during the removal experiments and enabled the removal of P under the conditions of acidic pH and relatively high P concentration without LDH dissolution.

XANES and XRR study on phase evolution of TiO2 films developed using HiPIMS

High power impulse magnetron sputtering (HiPIMS) is one of the recent advanced techniques for the development of high quality TiO2 thin films. Due to the formation of high energetic ions in the discharge, HiPIMS can produce various crystalline phases of TiO2 (anatase and rutile) with low roughness as compared to conventional direct current magnetron sputtering (DCMS). This work emphasizes on the effect of oxygen partial pressure in the evolution of phases and oxidation states of TiO2 films deposited using HiPIMS along with a comparative study against DCMS grown films under similar oxygen environment. TiO2 thin films were prepared with DCMS and HiPIMS, as a function of oxygen content in the sputter gas flow. Thickness, density and roughness were calculated using XRR fitting and analysis. It was observed that HiPIMS deposited films were smoother and denser than DCMS grown films. Crystallite sizes of HiPIMS deposited films were significantly lower than DCMS. Phase growth analyses were performed using X-ray diffraction (XRD), Raman and XANES (X-ray absorption near-edge spectroscopy of the Ti L2,3 and O K-edges) spectroscopy. In HiPIMS grown films, the increase in O2 partial pressure changed the phase from rutile to mixed and then to anatase phase whereas only rutile and mixed phases were detected in DCMS grown film under similar oxygen environment. HiPIMS developed films were smooth, uniform free from cracks as observed in FESEM and Atomic Force microscope (AFM) morphological images. Lognormal crystallite size distribution values decreased with increasing O2 partial pressure. Crystal field splitting values of (Δo) between ∼1.9 and 2.2 eV indicate crystalline phase formation by XANES Ti L2,3-edge analysis. These findings point to better crystalline growth TiO2 thin films as compared to DC-MS. HiPIMS grown films shows phase transformation of rutile into mix phase and anatase with increase in oxygen partial pressure.

Sol-Gel Route for the Synthesis of CoFe2-x Er x O4 Nanocrystalline Ferrites and the Investigation of Structural and Magnetic Properties for Magnetic Device Applications.

This study reports the formation of Er-doped nanocrystalline cobalt ferrite with the formula CoFe2–xErxO4 (0.0 ≤ x ≤ 0.10) from nontoxic metal precursors Co(NO3)2·6H2O, Fe(NO3)3·9H2O, and Er(NO3)3·5H2O through an easy and economical sol–gel route in which citric acid is served as the chelating agent. The as-prepared powder was annealed at 700 °C for 3 h in ambient air to get the required spinel structure. The annealed samples were subjected to structural and magnetic characterization. The X-ray diffraction (XRD) data of the samples confirmed the cubic spinel structure formation. The average crystallite size evaluated from XRD data increased from 21 to 34 nm with the substitution of Er due to the larger atomic size of Er3+ than Fe3+. Moreover, the crystallite size obtained from XRD data are well matched with the particle size measured from transmission electron microscopy images. The lattice parameters obtained from XRD data agree well with the values estimated from theoretical cation distribution and Rietveld refinement calculation. The hysteresis curve exhibits the particles are soft ferromagnetic and the coercivity increased from 54.7 to 76.6 kA/m with maximum saturation magnetization, Ms = 61 emug–1 for 0.10 Er content. The squareness ratios were found to be less than 0.5, which indicates the single-domain nature of our particles. The blocking temperature measured from field cooled-zero field cooled curves is TB > 350 K for all the samples, which is much higher than the room temperature (300 K). The enhancement of saturation magnetization and coercivity has been explained based on the crystallite size, anisotropy constant, and cation distribution. Thus, the structural and magnetic properties of CoFe2O4 nanoparticles (NPs) can be tuned by Er incorporation and these NPs can be applied in different soft magnetic devices.

Development of MoO3-CdO nanoparticles based sensing device for the detection of harmful acetone levels in our skin and body via nail paint remover

Acetone plays a vital role as a cleanser for current cosmetic –products particularly nail paint, gels, fairness creams, face-wash, etc. Inhaling of acetone during cleaning skin and face can cause severe health issues which demand a highly sensitive acetone sensor. Formation of cadmium oxide (CdO) nanoparticles, two-dimensional molybdenum oxide (2D MoO3) nanosheets, and MoO3-CdO nanoparticles were investigated in terms of physical characteristics using the X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), Dynamic light scattering (DLS) and UV–visible absorption analysis. Characterization studies witnessed the formation of MoO3-CdO nanoparticles with a characteristic energy band gap, crystallite size, and particle size distribution as 3.80 eV, 38.69 nm, and 2–50 nm, respectively. As fabricated MoO3-CdO nanoparticles-based sensor exhibited an excellent response of 13.48 at 25 ppm with rapid response and recovery times of 6.95 s and 8.34 s respectively. Acetone sensing studies were also conducted for the products of a few commercial companies like Acetone pure, Beauty Company, and Lakme in nail polish removers. The study of MoO3-CdO nanoparticles may be used for acetone sensing in cosmetic applications.

Transmittance predictions for transparent alumina ceramics based on the complete grain size distribution or a single mean grain size replacing the whole distribution

A simple method, based on the equivalent composite model or the dense polycrystalline model, is proposed for predicting the in-line transmittance in ceramics with a grain size distribution of birefringent crystallites. It is shown that the transmittance predictions based on the Rayleigh-Gans approximation are indistinguishable from those based on Mie theory, so that the latter can be replaced by the former. Based on normal distributions of different position and width it is shown that size distributions with smaller mean sizes lead to higher transmittance, whereas the effect of the distribution width on the transmittance is comparatively weak (with the narrowest distribution being the most favorable for high transmittance). The key result of this paper is the fact that for the distributions investigated (normal and log-normal) the transmittance prediction based the whole grain size distribution can be replaced by a transmittance prediction based on the geometric mean of the intensity-weighted distribution.

Crystallite size distribution by two-dimensional XRD

The crystallite size distribution is an important parameter affecting the processing and properties of materials or products containing crystallites. The X-ray diffraction pattern collected with a two-dimensional detector may contain one or several spotty diffraction rings when an appropriate X-ray beam size is used. The spottiness of the diffraction ring is related to the size, size distribution, and orientation distribution of the crystallites. The intensity of a diffraction spot may represent its volume or size of a crystallite when a perfect Bragg condition is met. This paper introduces the algorithms and procedure to evaluate crystallite size distribution from a 2D diffraction pattern by rocking scan.

Thermal and Crystallization Behaviour of Polyphenylene Sulfide in Engineering Polymer Blends with HDPE

Abstract The thermal and crystallization behaviour of polyphenylene sulfide (PPS) in its blends with high density polyethylene (HDPE) is reported. Three grades of HDPE ranging in MFI from 0.4 to 52 were used in the investigation. The effect of composition and molecular weight of HDPE on the crystallization process and morphology of PPS in the blends has been investigated by the technique of Differential Scanning Calorimetry (DSC). In the blends, PPS crystallizes in presence of molten HDPE. It is observed that the morphology of PPS in terms of crystallite size and crystallite size distribution in the blends is significantly affected by blending with HDPE. The temperature onset of melting was found to increase with increasing HDPE content and the melting peak width was found to decrease with increasing HDPE content. This indicates a larger crystallite size and a narrower crystallite size distribution of PPS in blends. The effect is more pronounced in HDPE-rich compositions. The extent of the variation in the temperature onset of melting and peak width were comparable for all the grades of HDPE. The degree of crystallinity of PPS in the blends is reduced significantly (55–70%) in HDPE-rich blends. Therefore, it is concluded that the crystallization of PPS is affected by the presence of HDPE melt. The crystallization scans of PPS in the blends, obtained in the cooling mode, did not show any evidence of accelerated nucleation. On the other hand, a marginal reduction in the temperature onset of crystallization was observed. The temperature range of crystallization of PPS in the blends was found to be less for all compositions except for 90/10 (PPS/HDPE). In summary it is concluded that blending of HDPE with PPS influences the crystal growth of PPS significantly although the effect on its homogeneous nucleation is also considerable. As a result, the morphology of PPS crystallized in blends is different from that of the homopolymer. The changes in the morphology of PPS are not sensitive to the molecular weight of HDPE probably because of the high temperature of PPS crystallization relative to the melting point of HDPE.

Dislocation structure and crystallite size distribution in plastically deformed Ti determined by X-ray peak profile analysis

Abstract Ultrafine-grained titanium produced by equal channel angular pressing and subsequent cold rolling is studied by X-ray diffraction. It is found that a texture exists in which the hexagonal basal planes are parallel to the longitudinal axis of the billet. The crystallite size distribution and the dislocation structure are determined by X-ray diffraction peak profile analysis. The median and the variance of the crystallite size distribution are obtained as m = 39 nm and σ = 0.14, respectively. The dislocation model of anisotropic broadening of peak profiles enables to determine the active slip systems. It was found that all three possible hexagonal Burgers vectors of dislocations exist, with the composition of 66% <a> type, 33% <c> type and 1% <c + a> type.

A FIB-SEM Study of Illite Morphology in Aeolian Rotliegend Sandstones: Implications for Understanding the Petrophysical Properties of Reservoir Rocks

Diagenetic illite growth in porous sandstones leads to significant modifications of the initial pore system which result in tight reservoirs. Understanding and quantifying these changes provides insight into the porosity-permeability history of the reservoir and improves predictions on petrophysical behavior. To characterize the various stages of diagenetic alteration, a focused ion beam – scanning electron microscopy (FIB-SEM) study was undertaken on aeolian sandstones from the Bebertal outcrop of the Parchim Formation (Early Permian Upper Rotliegend group). Based on 3D microscopic reconstructions, three different textural types of illite crystals occur, common to many tight Rotliegend sandstones, namely (1) feldspar grain alterations and associated illite meshworks, (2) tangential grain coats, and (3) pore-filling laths and fibers. Reaction textures, pore structure quantifications, and numerical simulations of fluid transport have revealed that different generations of nano-porosity are connected to the diagenetic alteration of feldspars and the authigenic growth of pore-filling illites. The latter leads to the formation of microstructures that range from authigenic compact tangential grain coatings to highly porous, pore-filling structures. K-feldspar replacement and initial grain coatings of illite are composed primarily of disordered 1Md illite whereas the epitaxially grown illite lath- and fiber-shaped crystals occurring as pore-filling structures are of the trans-vacant 1Mtv polytype. Although all analyzed 3D structures offer connected pathways, the largest reduction in sandstone permeability occurred during the initial formation of the tangential illite coatings that sealed altered feldspars and the subsequent growth of pore-filling laths and fibrous illites. Analyses of both illite pore-size and crystallite-size distributions indicate that crystal growth occurred by a continuous nucleation and growth mechanism probably controlled by the multiple influx of potassium-rich fluids during late Triassic and Jurassic times. The detailed insight into the textural varieties of illite crystal growth and its calculated permeabilities provides important constraints for understanding the complexities of fluid-flow in tight reservoir sandstones.

Photocatalytic performance evaluation of visible active α-SnWO4 under different wavelengths

In current scenario, researches on visible light driven metal oxide semiconductor photocatalysts have much attention due to its better photocatalytic performance under solar radiation. The commercialized mixed phase TiO2 (Degussa P25) with anatase and rutile phase shows enhanced photocatalytic performance under UV light irradiation compared to its pristine phases. However, the performance of Degussa P25 is limited to UV region due to wide band gap. Among various metal oxide semiconductor photocatalysts, stannous tungstate (SnWO4) has attained much attention due to its favorable band gap and polymorphs nature. In this study, SnWO4 in α-phase was prepared via solvothermal synthesis. The structural analysis confirms the high crystalline nature of the sample with crystallite size distribution in nano scale in α-phase. The photocatalytic performance of the sample was performed under different wavelengths such as red light (700–635 nm), green light (560–520 nm), blue light (490–450 nm) of visible irradiation and in white light (700–400 nm). The sample showed enhanced photocatalytical performance in all the wavelengths compared to DP 25. The sample out performed in 490–450 nm (blue light) compared to white and other wavelength irradiation. The enhancement in the photocatalytic performance of the sample under blue light may be ascribed to the synergetic effect of the absorption of the sample and the light source.

Nitriding and Denitriding of Nanocrystalline Iron System with Bimodal Crystallite Size Distribution.

An artificially prepared nanocrystalline iron sample with bimodal crystallite size distribution was nitrided and denitrided in the NH3/H2 atmosphere at 350 °C and 400 °C. The sample was a 1:1 mass ratio mixture of two iron samples with mean crystallite sizes of 48 nm and 21 nm. Phase transformations between α-Fe, γ’-Fe4N and ε-Fe3-2N were observed by the in situ X-ray powder diffraction method. At selected steps of nitriding or denitriding, phase transformations paused at 50% of mass conversion and resumed after prominent variation of the nitriding atmosphere. This effect was attributed to the separation of phase transformations occurring between sets of iron crystallites of 48 nm and 21 nm, respectively. This was due to the Gibbs–Thomson effect, which establishes the dependence of phase transformation conditions on crystallite sizes.

Heat-stimulated crystallization and phase transformation of titania nanoparticles

To better understand the fundamental aspects of nanoparticle formation and transformation in the TiO2-H2O system the amorphous titania was synthesized as a precursor to studying crystal genesis, evolution, and transformation under heat treatment in air. The necessary depth of study was provided by comprehensive analysis using methods of PXRD, HT-PXRD, DSC-TG, TEM, BET adsorption, and helium pycnometry. The smallest crystallite size of the anatase phase is shown to be defined by the size of the initial amorphous titania nanoparticles. The amorphous state of initial titania nanoparticles is stabilized by water molecules incorporated into their structure. The anatase-to-rutile phase transition occurs when the average crystallite size of the anatase reaches the value of 35–45 nm. An explanation for a drastic change of the average crystallite size during the anatase-to-rutile transition repeatedly found in researches is in the difference in shapes of curves of crystallite size distribution.

Enhancement of electrical and magnetic properties of Al3+ substituted CuZn nano ferrites with structural Rietveld refinement

Nanoparticles of Cu0.65Zn0.35AlxFe2-xO4 (x = 0.00 to 0.10, in the step size of 0.025) were synthesized by employing the auto-combusted sol–gel process and annealed at 700 ˚C. The effect of Al3+ substituted Cu-Zn mixed nanoferrites on the structural, magnetic, dielectric, and electrical properties has been investigated. The behavior of the structural exploration of these compositions has been implemented by the X-ray diffraction technique and further refined through the Rietveld refinement technique which provides structural homogeneity parameters like crystal structure, crystallite size and cation distribution. The surface morphology revealed the existences of spherical shape nano-grains with narrow size distribution. Dielectric properties display reduction in space charge polarization with Al3+ content. From the electric modulus analysis, broader semicircles are obtained by the substitution of Al3+ in our parent compound. The addition of upto 5% Al content shows increment of both grain (Rg) and grain boundary resistance. Enhancement of Rg contribution with Al3+ content at high frequency region reduced eddy current losses remarkably. The rising trend of σac depicts the normal nature of the investigated materials with frequency, which is clarified by the electron hopping mechanism. The saturation magnetization (Ms) increased with nonmagnetic Al3+ substitution up to x =0.075 and upon application of Law of Approach to Saturation various hysteresis parameters like Ms, anisotropy constant are obtained.

Refinement of fundamental characteristic properties with homovalent Er/Y partial replacement of YBa2Cu3O7−y ceramic matrix

In the current work, the effect of partial substitution of Er-sites for the Y-sites in the bulk YBa2Cu3O7−y (YBCO) crystal system on the fundamental superconducting, electrical, crystallinity and structural morphology features is examined together with the reasons by means of powder X-ray diffraction (XRD), temperature-dependent electrical resistivity (ρ-T), scanning electron microscopy (SEM), electron dispersive X-ray (EDX) investigations and deduced calculation parameters. All the experimental test results show that the erbium impurities are successfully substituted by the yttrium sites in the bulk Y-123 crystal system, confirmed by sensitively the EDX and ρ-T measurement results. Moreover, it is found that all the fundamental characteristic quantities improve with the increment in the Er/Y partial substitution level up to the value of x = 0.03 beyond which the features tend to degrade dramatically. In this respect, the bulk Y1−xErxBa2Cu3O7−y ceramic compound prepared within the molar ratio of x = 0.03 crystallizes in the orthorhombic space group P4/mmm with a little distortion due to the refinement in the crystallinity quality, crystallite growth, oxygen ordering degree, scattering mechanism, intra and inter-grain boundary couplings, grain alignment distributions and orientations. The XRD results show that the optimum erbium content enables to develop seriously the fundamental crystallographic features (lattice strain, lattice cell constants, crystallite size distribution, dislocation density ratio, oxygen concentrations in the unit cells) of Y-123 crystal structure. However, the excess Er/Y substitution leads to enhance considerably the systematic structural problems and inhomogeneous distribution of strains (formed by the structural defects) in the YBCO crystal structure. Thus, the phase transition from orthorhombic to tetragonal (structural O–T transition) crystal structure is observed. In fact, the XRD result displays that the trivalent Er3+ particles may partially be replaced by the divalent Cu2+ host atoms in the bulk Y-123 crystal structure after the critic substitution level of x = 0.03. The optimum Er concentration causes to form more thermodynamically activated super-electrons in the homogeneous superconducting cluster percentages in the paths due to the induced polaronic effect, and accordingly the intrinsic overdoped nature of Y-123 ceramic system transits into optimally doped state. Similarly, the erbium ions enable to increase the mobile hole carrier concentration and homogeneities in the oxidation state of superconducting grains. Namely, the amplitude of pair wave function (Ψ = Ψ0e-iφ) is strength enough to form bipolarons in the polarizable lattices and localize of densities of electronic states (DOS) at Fermi level. SEM investigations picture that the surface morphology view and crystallinity quality develop remarkably with the increment in the erbium content up to the critical dopant level of x = 0.03 where the sample exhibits the best grain alignment orientations, densest and smoothest surface morphology with the combination of lowest porous and largest particle distributions well linked each other. All in all, this comprehensive work based on the analysis of Er/Y partial replacement mechanism along the YBa2Cu3O7−y ceramic matrix may open up a newly/novel and feasible area for the advanced engineering, heavy-industrial technology and large-scale applications of type-II superconducting materials.

Effect of sintering conditions on structural and morphological properties of Y- and Co-doped BaZrO3 proton conductors

BaZrO3-based materials doped with a trivalent cation have excellent chemical stability and relatively high proton conductivity which makes them potential proton conducting oxide materials for various electrochemical device applications such as hydrogen processing, high-temperature electrolysis, and solid electrolyte in fuel cells. However, BaZrO3 showed poor sinterability, requiring high sintering temperatures (1700–2100 °C) with longtime sintering (20–100 h) to achieve the desired microstructure and grain growth. This sintering problem can be solved by slightly doping BaZrO3 with a sintering aid element. Therefore, in this study, two different zirconate proton conductors: BaZr0·9Y0·1O3-α (BZY) and BaZr0·955Y0·03Co0·015O3-α (BZYC) were sintered in an air atmosphere and an oxygen atmosphere for 20 h in the temperature range of 1500–1640 °C. The sinterability was evaluated by analyzing the XRD diffraction patterns, lattice constant, lattice strain, crystallite size, relative density, open porosity, closed porosity, surface morphology, grain size, and grain boundary distribution, using the XRD, SEM, EDX, and Archimedes density measurement methods. It is concluded that in an oxygen atmosphere, sintering aid Co not only improves the relative density but also produces highly dense fine particles with clear grain boundaries which are promising for electrochemical hydrogen device applications.

Synthesis of α-Fe2O3/SiO2 nanocomposites for the enhancement of acetone sensing performance

Herein, a novel gas-sensing nanocomposite of α-Fe2O3/x%SiO2 (x = 0, 10, 15, 20, 30) was synthesized for the first time by sol-gel. With an increase in SiO2 concentration to 30 %, the average crystallite size and pore-size distribution of samples exhibited a decreasing trend. The surface area also showed an increasing trend with the introduction of SiO2. Gas-sensing measurement results revealed that the α-Fe2O3/20 %SiO2 nanocomposite showed the highest response (Ra/Rg = 50.20) to 500 ppm acetone at its optimal operating temperature of 290 °C, which was about 34 times higher than that of the pure α-Fe2O3 gas sensor. The response/recovery time of the α-Fe2O3/20 %SiO2-based sensor to 500 ppm acetone was 14 s/7 s. The response/recovery time of α-Fe2O3 was 25 s/21 s. After SiO2 was modified, the response/recovery speed increased. The results demonstrated the potential of α-Fe2O3/20 %SiO2-based gas sensors for sensitive and selective detection of acetone.

Hydrothermal synthesis of flower-like Cr2O3-doped In2O3 nanorods clusters for ultra-low isoprene detection

Isoprene is a typical biomarker for nonalcoholic fatty liver disease (NAFLD) and can be used for early screening in breath diagnosis. In this study, a simple hydrothermal synthesis of flower-like Cr2O3-doped In2O3 nanorods clusters materials for ultra-low isoprene detection was reported. This special flower-like nanorods clusters structure has the large specific surface area and the Cr2O3 doping improves in the distribution of different oxygen components, crystallite size, and carrier concentration, which synthetically contributes to the enhanced isoprene sensing performance. The results show that among all the sensors, the 1 wt% Cr2O3-doped In2O3 sensor exhibits reliable ppb-level detection ability with a concentration less than 5 ppb. Meanwhile, the sensor shows good long-term stability for 4 weeks and considerable selectivity over other common breathing gases (benzene, acetone, octane, pentane, ethanol, ammonia, and nitrogen dioxide). Furthermore, the sensor has good humidity resistance under different ambient humidity (0–92% RH). Thus, we believe the sensor based on the flower-like Cr2O3-doped In2O3 nanorods clusters has a potential application value for the detection of trace isoprene in breath analysis.

A linearized integral model for determining the nucleation parameters from metastable zone width data

By incorporating the combined effect of nucleation and growth rates on the crystallite size distribution, a linearized integral model was proposed in this work according to classical nucleation theory to determine the nucleation parameters from the metastable zone width (MSZW). Instead of the nucleation pre-exponential factor, the combined constant of nucleation and growth was introduced to account for the combined effect of nucleation and growth rates crystallite size distribution at the nucleation point. From the MSZW data of aqueous L-glycine solutions at different cooling rates for various initial saturation temperatures, the values of the interfacial energy and the combined constant of nucleation and growth were determined and discussed by using the proposed model in this work, as well as various models reported in the literature. The results indicated that the proposed model in this work leads to a lower value of the interfacial energy and a poorer fit of the data than those by the classical 3D nucleation theory approach.

Additive manufacturing of magnesium alloy using uniform droplet spraying: modeling of microstructure evolution

In this study a material model is developed to predict the solidification microstructure of an additive-manufactured, fully dense magnesium (Mg) alloy using uniform droplet spraying (UDS). Specifically, the crystallite size distribution is simulated by a solidification model, consisting of a nucleation/fragmentation and a constrained growth description, calibrated via microstructural data from a single droplet splat. This is enabled by a semi-analytical thermal modeling framework, based on the superposition of moving Green’s and Rosenthal functions for the temperature field generated by a Gaussian source distribution. The model is implemented for layered ellipsoidal deposit sections on planar substrates by multi-pass spraying, and its predictions are validated against measured crystal sizes by image analysis of experimental micrographs of a Mg97ZnY2 alloy, to an error margin of ± 15%. The computationally efficient simulation provides insights to the deposit microstructure, and is intended as a process observer in a closed-loop, adaptive control scheme based on infrared temperature measurements.

Physical properties of PVDF-GO/black-TiO2 nanofibers and its photocatalytic degradation of methylene blue and malachite green dyes.

Black TiO2 and graphene oxide (GO) have attracted intensive attention as an effective catalyst on visible light driven for photodegrading of dyes. In this study, nano-black TiO2 was prepared by a simple hydrogenation of the anatase titanium oxide, and the graphene oxide was prepared by applying the modified Hummers method. The diffuse reflectance spectroscopy has been investigated to find out the optical energy gaps of the treated and nano-black samples. The prepared powders and nanofiber membranes are carefully examined to ensure their single phase and compound structure formation as well as to measure the equivalent crystallite size and particle distributions. The optimum degradation efficiency of malachite green and methylene blue dyes occurred at pH values of 8 and 10, respectively. The maximum photocatalytic degradation efficiencies of malachite green (MG) and methylene blue (MB) were found to be 74 and 39%, respectively, under visible light after 30min. The degradation efficiency of MG is peaked at pH8 and 20mg of the nano-black TiO2. The stability and flexibility of the nanofibers allow their application in a continuous system and can be reused after several cycles.