Granular Shape Research Articles

Impact of catalyst support morphology on 3D electrode structure and polymer electrolyte membrane fuel cell performance

AbstractPorous carbon‐based electrodes are frequently applied in electrochemical energy technologies, for instance in fuel cells and redox flow batteries. In previous work, we observed that the final structure of a fuel cell electrode is dominated by both the morphology of the support material and its processing into a 3D porous structure. Herein, the impact of catalyst support morphology on the performance of polymer electrolyte membrane fuel cells was studied comparing carbon‐supported platinum catalysts only differing in the shape of the carbon support material with otherwise similar features. Carbon‐supported Pt catalysts were obtained by carbonization of polyaniline (PANI) in long fibrous, short fibrous, and granular shape. The chemical identity of the PANI precursors was demonstrated by FTIR spectroscopy and elemental analysis (EA). The final carbon‐supported platinum catalysts were characterized by EA, Raman spectroscopy, XRD, and TEM exhibiting similar degree of carbonization, nanoparticle size, and nanoparticle dispersion. The effect of support morphology and the resulting differences in the 3D structure of the porous electrode were investigated by focused ion beam‐scanning electron microscopy slice and view technique and correlated to their fuel cell performance.

Microstructural/mechanical characterizations of electron beam welded IN738LC joint after post-weld heat treatment

The effect of post-weld heat treatment on microstructure and mechanical properties of electron beam welded IN738LC joint has been investigated. The fusion zone consists of γ-Ni matrix, bimodal-size γʹ particles, granular MC carbides (Ti-rich) and Cr-rich M23C6 carbide chain in IN738LC joint subjected to post-weld heat treatment. The secondary γʹ particle in fusion zone precipitates and grows ceaselessly with the increased aging time. The coarsening of γʹ particle follows the Lifshiitz-Slyozov-Wagner coarsening theory with a constant coarsening rate of 1.003 × 10−27m3/s. The secondary γʹ particle in base metal shows a similar size with that of fusion zone, but a lower volume fraction (52%) than that of fusion zone (54%). M23C6 carbide is easier to precipitate along high angle grain boundaries. As aging time increases, the morphology of M23C6 carbide changes from discrete granular shape to continuous chain. The thickness of M23C6 carbide also increases dramatically. Owing to smaller grain size and higher solute concentration in fusion zone, more M23C6 carbides form in FZ than that of base metal. With the increased aging time, the tensile strength of IN738LC joint at 900°C decreases gradually, while the elongation of joint firstly increases and then decreases, which is attributed to the increased channel width of γ-Ni matrix. Due to the formation of continuous M23C6 carbide chain, the rupture life of IN738LC joint firstly increases and then decreases as aging time increases. Combined with the mechanical properties and size stability of γʹ precipitates in IN738LC joint, 1125°C/2 h + 850°C/24 h is an optimized post-weld heat treatment regime.

Neurogenesis of Adult Circulating Blood Mononuclears in Vitro

Cellular therapy of injuries of the nervous system with autologous cellular material of the patient requires the development of methods of neurodifferentiation of stem and progenitor cells of the adult organism. The use of autologous cells is the most acceptable from the point of view of biosafety and compatibility. In our work, we investigated the possibility of directed neurogenesis of circulating blood precursors adhered fraction, obtained from the patient with spinal cord injury. These cells were cultured for 2 weeks using neuroinducers (retinoic acid, BDNF, NGF). During the first 3 days of cultivation, the adherent fraction of cells consisted of round cells of small and medium size with a large nucleus and a narrow rim of the cytoplasm, which gradually stratified and formed an oval and granular shape. Subsequent cultivation showed that the cells acquire morphological characteristics of different types of cells of the nervous system. At the end of this period, the predominant cell population was Nest+. The patient’s own cells after stimulation of neurogenic differentiation in vitro were removed, washed from medium components and injected into the spinal canal. Intracisterial and paraventricular administration of this fraction to the patient significantly improved impaired function.

EVALUATION OF HARVEST AGE ON PHYSICOCHEMICAL PROPERTIES AND ANTIOXIDANT CAPACITY OF BUTTERNUT PUMPKIN FLOUR

<p>Processing pumpkins (Cucurbita moschata) is one alternative to prolong its shelf life and to provide flexibility in uses.. The aim of this research was to find the right harvest time to produce pumpkin flour with high yield and good quality. The experiment was designed using a complete randomized block design with 4 replications. The treatments included the harvest age of 15, 20, 25, and 30 days after fruit set (DAFS). The data obtained were processed using ANOVA, and continued tested using DMRT. The pumpkin with various maturity levels was analysed for starch, moisture, ash, lipid, protein and carotenoid contents. Yield, potential as antioxidant, granular shape and size were also determined The results indicate that pumpkin harvested at 25 DAFS produced high yield and good quality flour.</p>

A critical state based viscoplastic model for crushable granular materials

Experimental studies have confirmed that the critical state of a granular material varies with alteration in granular fabric, particle shape and grain size. On the other hand, granular materials demonstrate significant strain rate dependency in the presence of particle crushing. While the first feature is well explored, the strain rate effects on the crushability of granular material and consequent critical state alteration are less ventured. This study highlights the strain rate dependence of the critical state of crushable granular materials like sand. A rate-dependent model is proposed bridging the macro and microscopic understanding. The model follows a consistent viscoplastic formulation without using any overstress function. The proposed model considers various loading rate effects at different porosities, confinements and pore water drainage conditions. Further, it can predict the strain rate-dependent particle crushing and dilation features that affect the critical state of granular materials. The model has been validated by comparing its responses with both the experimental and discrete particle simulations for drained and undrained triaxial conditions. An implicit stress return integration scheme is devised to enable accurate numerical response from the model.  Finally, a parametric study is presented that envisages the evolution of critical state due to coupled strain rate and particle crushing effect.

Investigation to Understand the Co Ions Inclusion in Ba3SnO Antiperovskites Structure

The current research focuses on the fabrication and characterization of barium tin oxide antiperovskite oxide Ba3SnO. BaO and Sn2O were used as precursors to synthesise the Ba3SnO by using solid state ceramic method. Co ion has been implanted using Pelletron Accelerator with different doses 1013, 5×1013, 1014 ions/cm2. The study includes the investigations of penetration depth range of Co ions in the target material, structural, surface morphology, verification of elemental composition, and band gap energy by using the characterization techniques SRIM, XRD, SEM, EDX, FTIR, and UV-Vis spectroscopy respectively. Phase identification of desired material assures by XRD. SEM results showed that the rough and sharp rod shape varies into a very smooth and fine granular shape by ion implantation. EDX plots confirm the existence of basic elements like Ba, Sn, Co and O. The FTIR identify the unknown material and components which confirmed the formation of B3SnO and incorporation of Co ions. UV-Vis spectroscopy results revealed that increasing the implanted ion dose causes a slight increase in band gap energy from 2.61 to 2.88 of this material. The obtained results allow us to conclude that the prepared sample contains a fine structure with no impurity. Therefore, we can say that this process is ideal for obtaining fine structured Ba3SnO.

Brevundimonas diminuta isolated from mines polluted soil immobilized cadmium (Cd2+) and zinc (Zn2+) through calcium carbonate precipitation: Microscopic and spectroscopic investigations

The toxic metal(loid)s TMs resistant bacterium Brevundimonas diminuta was isolated for the first time from mines polluted soil in Fengxian, China, and assessed for its potential for Cd and Zn precipitation in Cd and Zn co-contaminated aqueous solution at various Cd and Zn levels (20, 40, 80, 160, and 200 mg L−1), pH values (5, 6, 7, 8, and 9), and temperatures (20, 25, 30, and 35 °C). B. diminuta showed a high resistance to both Cd and Zn and was able to precipitate up to 99.2 and 99.7% of dissolved Cd and Zn respectively, at a pH of 7 and temperature of 30 °C. B. diminuta reduced the dissolved concentrations of Cd and Zn below the threshold levels in water. The 3D-EEM analysis revealed the presence of extracellular polymeric substances (EPS) such as tryptophan indicating bacterial growth under Cd/Zn stress. FTIR showed polysaccharides, CO32−, CaCO3, PO43−, and proteins, which may enhance bacterial growth and metal precipitation. SEM-EDS confirmed the leaf-like and granular shape of the biological precipitation and reduction in the percent weight of TMs, which promoted the adhesion/adsorption of Cd2+, Zn2+, and Ca2+. Moreover, XRD analysis confirmed the precipitation of Cd, Zn, and Ca in the form of CdCO3/Cd3(PO4)2, ZnCO3/ZnHPO4/Zn2(OH)PO4/Zn3(PO4)2, and CaCO3/Ca5(PO3)4OH, respectively. These findings indicate that Brevundimonas diminuta can be used for the bioremediation of TMs-contaminated aquatic environments.

Химический синтез наноструктурированного магнитотвердого сплава системы Nd-Fe-B

Hard magnetic nanopowders of the Nd15Fe78B7 alloy were synthesized from mixtures of Nd, Fe and Fe-B oxides with CaH2 in a hydrogen atmosphere at 800 °C by a reduction-diffusion process. Nd, Fe, Fe-B oxides were synthesized by chemical deposition. The resulting particles had a granular shape with an average size: Nd2O3 — 50 nm, Fe2O3 — 95 nm, Fe3BO6 — 57 nm. The particle size of the Nd15Fe78B7 alloy was 45–140 nm. It is shown that the proposed method is suitable for obtaining nanopowders of hard magnetic alloys of the Nd-Fe-B system.

Three‐dimensional quantitative analysis on granular particle shape using convolutional neural network

AbstractTo identify all desired shape parameters of granular particles with less computational cost, this study proposes a three‐dimensional convolutional neural network (3D‐CNN) based model. Datasets are made of 100 ballast and 100 Fujian sand particles, and the shape parameters (i.e., aspect ratio, roundness, sphericity, and convexity) obtained by conventional methods are used to label all particles. For the model training, by feeding the slice images of particles into the model, the contour of particles is automatically extracted, thereby the shape parameters can be learned by the model. Thereafter, the model is applied to predict shape parameters of new particles as model testing. All results indicate the model trained based on slice images cut from three orthogonal planes presents the highest prediction accuracy with an error of less than 10%. Meanwhile, the accuracy for concave and angular particles can be guaranteed. The rotation‐equivariant of the model is confirmed, in which the predicted values of shape parameters are roughly independent of orientations of the particle when cutting slice images. Superior to conventional methods, all desirable shape parameters can be obtained by one unified 3D‐CNN model and its prediction is independent of particle complexity and the number of triangular facets, thus saving computation cost.

Structural characterization, physicochemical properties and in vitro digestion of finger millet–resistant starch prepared by different methods

SummaryIn this study, the structural, physicochemical and digestion characteristics of finger millet–resistant starch (FRS) prepared by ultrasonic (UP‐FRS), ultrasonic‐autoclaving (UAP‐FRS), enzymolysis (EP‐FRS) and ozonation (OP‐FRS) were studied. Different preparation methods have different degrees of damage to the morphological structure and granular shape of the starch, but the resistant starch obtained by ultrasonic, ultrasonic‐autoclaving and enzymolysis exhibited a same crystallinity pattern (B‐type polymorph), and typical V‐type modified starch was obtained by ozone treatment. That caused them to have different physicochemical properties. The solubility (8.2%) and swelling power (2.5%) of OP‐FRS were the smallest; the sedimentation value of the UAP‐FRS increased steadily with the increase of time and showed the largest (16.7%). UP‐FRS required the most energy for complete gelatinization (ΔH, 145 J g−1), and the gelatinization temperature range of the samples was significantly different (P < 0.05). In addition, UP‐FRS and OP‐FRS had strong anti‐digestion ability in vitro, and their digestion rate was lower than 30%. All these results are expected to provide information on the preparation and application of FRS, and may indicate that the specific processing of food before consumption could be used as new pathways for regulating the digestibility properties of food.

Microstructure and compressive properties of solution heat-treated magnesium-Mg2Si in-situ composite foams after complex modification

In this study, open-cell Mg composite foams reinforced with in-situ Mg2Si were prepared. In order to refine the Mg2Si compound, the composite foams were co-modified with Y + Sb elements followed by solution heat treatment. The influences of complex modification and holding time of solution heat treatment on the microstructure and compressive properties of the composite foams were studied. The experimental results show that the morphology of Mg2Si is effectively changed by complex modification. The coarse dendritic primary Mg2Si (∼40 μm) is altered to the fine polygonal shape (∼10 μm); the coarse eutectic Mg2Si is transformed to a long rod or granular shape. Both compressive strength and energy absorption capacity of the composite foams are significantly increased. Additionally, with the increasing holding time of solution heat treatment, the eutectic Mg2Si undergoes obvious spheroidization, and the corner of the primary Mg2Si occurs passivation. Consequently, the compressive strength and energy absorption capacity are further improved.

Effect of pH on the Morphology and Microstructure of ZnO synthesized using Ananas comosus Peel Extract

This research investigated the effect of synthesis pH on the microstructure and morphology of the zinc oxide (ZnO) particles prepared using pineapple (Ananas comosus) peel extract. In this study, ZnO powder were synthesized at different pH, i.e. 8, 9, 10, 11, and 12. ZnO samples were characterized using UV-Vis spectroscopy, Fourier Transform InfraRed spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The UV-Vis absorbances spectroscopy shows the optical absorption peak of the ZnO sample occurred in a wavelength range of 300-360 nm, with bandgap energy of ∼3.22 eV. The FT-IR spectrum shows the peak of Zn-O absorption at the wavenumber of 437.55 cm-1 and the reduction of aromatic compounds with increasing of pH. The micrograph of ZnO particles synthesized at different pH shows that the pH affected the size and shape of ZnO. Micro-sized particles with a granular shape have been found at pH 8, and 9, a spherical shape have been found at pH 10, while micro-sized flower-shaped particles have been found at pH 11 and 12. The XRD pattern reveals a wurzite hexagonal ZnO crystal phase with the hkl plane of (101) as the strongest peak, as well as the purity of the sample increasing as the pH value rises. As the conclusion, synthesis pH has a significant impact on the optical, structural, and morphological properties of ZnO biosynthetic powder.

The effects of dual modification on functional, microstructural, and thermal properties of tapioca starch.

The aim of this study was to investigate the effects of dual modification on the functional, microstructural, and thermal properties of tapioca starch. Tapioca starch was first hydrolyzed by 0.14 M HCl for 0, 6, 12, 18, and 24 hr and then hydroxypropylated by adding 0%, 10%, 20%, and 30% (v/w) propylene oxide. The degree of hydroxypropylation, solubility, water absorption, rheological, thermal, and microstructure characterization of dually modified tapioca starch was determined. Hydroxypropylation did not cause any considerable changes in the starch granular size and shape of tapioca starch. Acid hydrolysis disrupts the starch granules, and the starches with smaller sizes were produced. The degree of molar substitution (DS) of dual modified starches ranged from 0.118 to 0.270. The dual modified starches significantly had higher solubility than native starch (p < .05). Hydrolysis of starches with acid decreases swelling power while hydroxypropylation increases the swelling power. The results also showed lower gelatinization (To, Tp, Tc, and ΔH) and pasting parameters (the peak and final viscosity, peak time, and pasting temperature) for the dual modified starches than other treatments. In summary, this study showed that dually modified tapioca starch has potential application in dip molding and coating.

Accelerated carbonation of alkaline construction sludge by paper sludge ash-based stabilizer and carbon dioxide

Construction sludge frequently has high alkalinity after its generation or during the intermediate treatment process. The aim of this study is to experimentally investigate the potential of combining accelerated carbonation and a paper sludge ash-based stabilizer (PSAS) to neutralize the alkalinity of construction sludge in a short period and to improve its strength for use as a recycled material. The experimental results indicate that the addition of a PSAS significantly granulated the alkaline sludge, and once granulated, the PSAS successfully accelerated the pH neutralization of the alkaline sludge. It was also found that the decrease in dry density ρd and the degree of saturation Sr of the PSAS-treated sludge was able to reduce the period required for the pH neutralization, tN. The decrease in ρd is thought to allow fresh CO2 gas to penetrate the specimen more easily. However, if Sr is below a certain limit, it does not strongly facilitate the reduction of tN. This implies that pH neutralization cannot be accelerated when the amount of water in the sludge is below a certain level. Moreover, it was found that mean particle diameter D50 also affected tN. The strength development of the PSAS-treated sludge was evaluated using a series of cone index tests. It was found that the strength of the alkaline sludge without the PSAS was significantly decreased by accelerated carbonation, but was significantly increased even after accelerated carbonation when the PSAS was present. Due to the porosities of the remaining PS ash particles, most of the contribution of the water absorption and retention performance of the PSAS to the strength development of the PSAS-treated sludge was secured after accelerated carbonation. In addition, the granulated particles of the PSAS-treated sludge retained their granular shape to some extent. Therefore, it is presumed that the friction and interlocking of the particles did not decrease significantly. It was also found that, after carbonation, the qc of the PSAS-treated sludge increased more rapidly than that of the alkaline sludge without the PSAS. A further detailed examination of the test results showed that under air-curing conditions, the qc of the treated sludge with accelerated carbonation increased relatively gradually compared to that of the treated sludge without accelerated carbonation.

Effects of yttrium addition on microstructure and mechanical properties of Inconel 718 alloy produced by sub-rapid solidification

In order to improve the mechanical properties of Inconel 718 alloy produced by sub-rapid solidification, the yttrium (Y) element was added during casting. One alloy with 0.1% weight Y content (0.1Y) and a reference alloy without Y addition (0Y) were produced, which involved homogenization, cold rolling, intermediate annealing, and aging treatment. The influences of Y addition on the microstructure and mechanical properties of Inconel 718 alloy were examined. Due to the precipitation of Ni3Y and Ni17Y2 particles, 0.1Y alloy exhibited a refined grain size and a lower recrystallization fraction. The average grain size of 0Y homogenized sample and 0.1Y homogenized sample were about 50.8 μm and 29.5 μm, respectively. Besides, a higher fraction of δ phase precipitated in the 0.1Y annealed sample, including a large amount of granular or short-rod shape δ phases and a small amount of needle-like δ phases. The area fraction of δ phase in the 0.1Y annealed sample was ~10.45%. However, the area fraction of δ phase in the 0Y annealed sample was lower (~7.93%), and needle-like δ phase was hardly observed under this condition. Compared with 0Y alloy, 0.1Y alloy showed better tensile properties. The 0.1Y alloy after aging treatment exhibited an excellent combination of ultimate tensile strength (~1400 MPa), and total elongation (~20%) when deformed at room temperature.

Exploring the Biomaterial-Induced Secretome: Physical Bone Substitute Characteristics Influence the Cytokine Expression of Macrophages.

In addition to their chemical composition various physical properties of synthetic bone substitute materials have been shown to influence their regenerative potential and to influence the expression of cytokines produced by monocytes, the key cell-type responsible for tissue reaction to biomaterials in vivo. In the present study both the regenerative potential and the inflammatory response to five bone substitute materials all based on β-tricalcium phosphate (β-TCP), but which differed in their physical characteristics (i.e., granule size, granule shape and porosity) were analyzed for their effects on monocyte cytokine expression. To determine the effects of the physical characteristics of the different materials, the proliferation of primary human osteoblasts growing on the materials was analyzed. To determine the immunogenic effects of the different materials on human peripheral blood monocytes, cells cultured on the materials were evaluated for the expression of 14 pro- and anti-inflammatory cytokines, i.e., IL-6, IL-10, IL-1β, VEGF, RANTES, IL-12p40, I-CAM, IL-4, V-CAM, TNF-α, GM-CSF, MIP-1α, Il-8 and MCP-1 using a Bio-Plex® Multiplex System. The granular shape of bone substitutes showed a significant influence on the osteoblast proliferation. Moreover, smaller pore sizes, round granular shape and larger granule size increased the expression of GM-CSF, RANTES, IL-10 and IL-12 by monocytes, while polygonal shape and the larger pore sizes increased the expression of V-CAM. The physical characteristics of a bone biomaterial can influence the proliferation rate of osteoblasts and has an influence on the cytokine gene expression of monocytes in vitro. These results indicate that the physical structure of a biomaterial has a significant effect of how cells interact with the material. Thus, specific characteristics of a material may strongly affect the regenerative potential in vivo.

Polyaniline-Decorated Carbon as Composite Carrier for Improving PtNi Catalyst Durability

Polyaniline (PANI) was synthesized on carbon cloth with a diffusion layer by an electrochemical technique and characterized by Fourier-transform infrared spectrometry, x-ray photoelectron spectroscopy, and scanning electron microscopy. PANI polymerized by a potentiostatic and a pulse potential method showed different morphologies. The former showed a granular shape and the latter a reticular structure. The reticular PANI was more suitable as a catalyst carrier based on the results of a cyclic voltammetry test. A PtNi catalyst electrodeposited on the reticular PANI-decorated carbon cloth (PtNi/PANI(PP)-C) had a smaller particle size and a homogeneous distribution. PtNi/PANI(PP)-C exhibited a higher electrochemical active surface area and better electrocatalytic activity according to the cyclic voltammetry and single cell polarization tests. Linear sweep voltammetry measurements indicated that PtNi/PANI(PP)-C showed excellent oxidation-reduction reaction activity through a four-electron transfer pathway. The results of an accelerated durability test showed that the performance degradation of PtNi/PANI(PP)-C was slower than that of PtNi/C. The reticular PANI-decorated carbon carrier improved the electrochemical activity and durability of the catalyst.

Synthesis, characterization and fuel parameters analysis of linseed oil biodiesel using cadmium oxide nanoparticles

Linseed oil biodiesel (LSOB) was synthesized from linseed oil by cadmium oxide nanoparticles applying transesterification reaction of oil with methanol. Cadmium oxide nanoparticles were synthesized through the hydrothermal method using cadmium acetate as precursor, sodium hydroxide for precipitation and urea as capping agent. The main analytical tools such as FT-IR, powder XRD and SE microscope were used to characterize newly prepared cadmium oxide nanoparticles. The appearance of new absorption band at 670 cm−1 has been assigned to Cd–O stretching vibration. XRD pattern indicate the purity and gave average particle size of 52 nm by Debye-Scherer formula. SEM images show granular shape of cadmium oxide nanoparticles with average particle size of 43 nm. The formation of linseed oil biodiesel was investigated using FT-IR and proton & carbon-13 NMR. GC-MS analysis of linseed oil biodiesel indicated six types of fatty acid methyl esters ranging from C16–C22 (mixture of both saturated and unsaturated). The fuel properties such as density, viscosity, cloud, pour and flash point were determined and compared with both ASTM standards for biodiesel and diesel.

Production of cross-linked resistant starch from tapioca starch and effect of reaction conditions on the functional properties, morphology, X‑ray pattern, FT-IR spectra and digestibility

The aim of this study was to investigate the effect of cross-linking temperature and pH on resistant starch (RS) formation as well as the functional, structural and morphology properties of tapioca starch. Tapioca starch was cross-linked using sodium trimetaphosphate (STMP) and sodium tripolyphosphate (STPP) at various temperature and pH. Increase in the reaction temperature and pH increased RS content and decreased swelling power (SP) of the samples. The sample cross-linked at 60 °C and pH 12 had the highest RS content (84.8%) and the lowest SP (3.0 g/g). The correlation coefficient between RS content and SP was 0.96. Cross-linking altered the pasting behavior significantly, while Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) patterns changed slightly. Cross-linking did not change the morphological structure and granular shape of the starch. In addition, cross-linked samples protect their original shapes during cooking and in vitro digestion probably since cross-linking restrict the water uptake and swelling due to the increase in the bonds within the molecule. Overall results proved that cross-linking at high temperature and high alkaline condition resulted in an increase in the RS content of tapioca starch.

Doping ZnS films with cobalt: Structural, compositional, morphological, optical, electrical, magnetic and photocatalytic properties

Co: ZnS (0, 6, 12 and 18 at. -%) nanostructures are mounted on glass substrates by chemical bath deposition (CBD) technique. X-ray diffraction (XRD) analysis shows cubic structure. Compositional study using X-ray photoelectron spectroscopy (XPS) establishes chemical states of Zn2+, S2−, Co2+ and some impurity elements such as C and O. Morphological study reveals the granular shape of the as-grown films. The average optical transmission is greater than 70% in the visible range. A band gap of about 3.70 eV is obtained. A slight enhancement of electrical properties is observed for a doping ratio equal to 12 at.-%. The photocatalytic activity of undoped ZnS and ZnS:(18 at.-% Co) is evaluated under visible light irradiation by following the discoloration of methylene blue. The photocatalytic efficiency achieved by ZnS:(18 at.-% Co) after 4 h of illumination is 69%.