Triangular Particles Research Articles

Finite element simulation of the effect of particle shape and thermal residual stress on the tensile properties of NbCp/Fe composites

To optimize the microstructure and properties of NbCp/Fe composites, this study considered factors such as load transfer, plastic strain, matrix damage, and interface debonding. A two-dimensional finite element model was constructed using ABAQUS software. Random adsorption algorithm was used to realize the random distribution of particles within the representative volume element, and interface damage was described using a cohesive zone model. The effects of particle shape and thermal residual stress on the tensile properties of NbCp/Fe composites were investigated. The results show that circular particles uniformly distribute the stress during the tensile process, effectively enhancing the tensile properties of the composites. Conversely, triangular particles, with obvious sharp corners, reduce their tensile properties, particularly in the presence of thermal residual stresses, which further aggravates the stress concentration between the particles and the matrix. This leads to a decrease in the strength and toughness of the material.

Colorimetric detection of platinum (IV) ions based on triangular silver nanoprism particles in aqueous environmental sample

Colorimetric detection of platinum (IV) ions based on triangular silver nanoprism particles in aqueous environmental sample

Synthesis and Investigation of Electrochemical Studies on Thulium Tellurite (TmTeO3) for Supercapacitor Electrode Application

Thulium tellurite ([Formula: see text]) is synthesized by hydrothermal method. It exhibits nearly cuboid-shaped particles along with triangular particles. [Formula: see text] is found to be monoclinic. The energy gap is 5.87[Formula: see text]eV, the Urbach energy value is 0.287[Formula: see text]eV and the refractive index is 1.881. The size of the particle is determined as 107[Formula: see text]nm. Optical transitions between energy levels assign absorption and emission peaks. Tm, was found in the oxide matrix as Tellurite. Magnetic susceptibility between 20[Formula: see text]K and 300[Formula: see text]K decreases with temperature, reaches saturation and aligns all Thulium spins. M–H curve confirms paramagnetic nature at 300[Formula: see text]K and feeble ferromagnetic nature at 77[Formula: see text]K. Cyclic voltammogram and chronopotentiometry analysis exhibit pseudo-capacitive behavior. The potential window is 0.82. Specific capacitance is found to be 87[Formula: see text]F/g. Chronopotentiometry analysis shows 55[Formula: see text]F/g specific capacitance. Impedance analysis shows a pseudo-capacitive nature. [Formula: see text] symmetrical supercapacitor device is fabricated with potential window of 1.52[Formula: see text]V. A specific capacitance of 37.75[Formula: see text]F/g at 1 A/g, energy density 6.055[Formula: see text]Wh kg[Formula: see text] and power density 760.99[Formula: see text]W kg[Formula: see text] was achieved. Impedance analysis shows low series resistance of 2.567[Formula: see text][Formula: see text] and charge transfer resistance of 0.473[Formula: see text][Formula: see text]. Cyclic performance with 80% specific capacitance retention is observed after 5000 cycles. The [Formula: see text] symmetric supercapacitor electrodes possess good electrochemical properties due to wider potential window, long cycle stability and notable energy density.

Shape-interaction dualism: unraveling complex phase behavior in triangular particle monolayers

This paper examines the effect of finite attractive and repulsive interactions on the self-assembly of triangular-shaped particles on a triangular lattice. The ground state analysis of the lattice model has revealed an infinite sequence of ordered structures, a phenomenon referred to as the ‘devil’s staircase’ of phase transitions. The model has been studied at finite temperatures using both the transfer-matrix and tensor renormalization group methods. The concurrent use of these two methods lends credibility to the obtained results. It has been demonstrated that the initial ordered structures of the ‘devil’s staircase’ persist at non-zero temperatures. Further increase of the attraction between particles or a decrease of the temperature induces the appearance of subsequent ordered structures of the ‘devil’s staircase’. The corresponding phase diagram of the model has been calculated. The phase behavior of our model agrees qualitatively with the phase behavior of trimesic acid adsorption layer on single crystal surfaces.

Investigation of the Thermodynamics for the Removal of As(III) and As(V) from Water Using Synthesized ZnO Nanoparticles and the Effects of pH, Temperature, and Time

In the present study, the removal of both As(III) and As(V) from aqueous solutions using synthesized ZnO nanomaterials was achieved. The ZnO nanomaterial was synthesized using a precipitation technique and characterized using XRD, SEM, and Raman spectroscopy. XRD confirmed the ZnO nanoparticles were present in the hexagonal wurtzite structure. SEM of the particles showed they were aggregates of triangular and spherical particles. The average nanoparticle size was determined to be 62.03 ± 4.06 nm using Scherrer’s analysis of the three largest diffraction peaks. Raman spectroscopy of the ZnO nanoparticles showed only ZnO peaks, whereas the after-reaction samples indicated that As(V) was present in both As(V)- and As(III)-reacted samples. The adsorption of the ions was determined to be pH-independent, and a binding pH of 4 was selected as the pH for reaction. Batch isotherm studies showed the highest binding capacities occurred at 4 °C with 5.83 mg/g and 14.68 mg/g for As(III) and As(V), respectively. Thermodynamic studies indicated an exothermic reaction occurred and the binding of both As(III) and As(VI) took place through chemisorption, which was determined by the ΔH values of −47.29 and −63.4 kJ/mol for As(V) and As(III), respectively. In addition, the change in Gibbs free energy, ΔG, for the reaction confirmed the exothermic nature of the reaction; the spontaneity of the reaction decreased with increasing temperature. Results from batch time dependency studies showed the reaction occurred within the first 60 min of contact time.

Replica symmetry breaking in a colloidal plasmonic random laser with gold-coated triangular silver nanostructures.

Plasmonic random lasers have drawn significant attention recently due to their versatility, low threshold, and the possibility of achieving tunable and coherent/incoherent outputs. However, in this Letter, the phenomenon of replica symmetry breaking is reported in intensity fluctuations of a rarely used colloidal plasmonic random laser (RL) illumination. Triangular nanosilver scatter particles produced incoherent RL action when used in a dimethylformamide (DMF) environment in a Rhodamine-6G gain medium. The use of gold-coated triangular nanosilver as the scatterer in place of triangular nanosilver offered a dual contribution of scattering and lower photo-reabsorption, which caused a reduction in the lasing threshold energy of 39% compared to that obtained with the latter. Further, due to its long-term photostability and chemical properties, a phase transition from the photonic paramagnetic to the glassy phase is observed experimentally in the RL system used. Interestingly, the transition occurs at approximately the lasing threshold value, which is a consequence of stronger correlation of modal behaviors at high input pump energies.

Heat transfer characteristic of particle flow around the out-wall of different geometries

In this study, large-scale simulations were carried out for different tube banks to explore the effect of geometrical factors. In addition, the heat transfer experiment of dense particles was carried out to validate the heat transfer model used in discrete element method. The stagnation zone and void zone with nearly triangular shape are found in staggered tubes. The stagnation zone with rectangular shape is formed between vertical adjacent tubes of the aligned tube, and the width of stagnation zone is one third of the tube diameter. A triangular particle blockade zone is formed in the rectangular stagnation zone. The heat transfer rate of staggered tubes is increased by 26% compared with that of the aligned tubes. The staggered elliptical-like combined tubes bank with chamfers significantly increase the heat transfer rate by 54.2% with the same heat transfer coefficient, compared with the staggered circular tubes bank. The local heat transfer performance can be enhanced by the addition of chamfers at the junction area of tubes. When penetration thermal resistance is dominant compared with the contact thermal resistance, the circular tube has higher heat transfer coefficient compared with elliptical-like combined tube with chamfers. The thermal resistance models for different tubes are developed.

Study on the grinding force of single grain in rail grinding based on open-type belt grinding

In the realm of machining, there exists a heightened demand for improved surface integrity of workpieces. Abrasive belt grinding presents several advantages, including a high grinding ratio, superior surface finish quality, and lower grinding temperature. Additionally, the precision placement of abrasive grains in the form of triangular pyramids further enhances the efficacy of this method. It has played an important role in the field of precision machining. Accurately predicting its grinding force is vital for improving its processing quality. In this study, an open-type belt grinding method was developed, the grinding force of triangular pyramid-shaped abrasive grains in rail grinding was analyzed and calculated using oblique cutting theory, the accuracy of the proposed model was verified experimentally, and the effects of abrasive rotation angle, wear height, cutting depth, grinding speed, and rake angle on the grinding force were analyzed, and the relevant laws were obtained. According to the findings, the grinding force displays an initial rise followed by a decline as the triangular pyramid abrasive particles' rotational angle increases. The grinding force demonstrates a linear growth in tandem with an increase in grinding depth. Furthermore, the grinding force rises proportionally with an increase in abrasive wear height. The proposed model can be used for the prediction and calculation of grinding forces of other shape abrasive grains as well.

Lemon-Juice-Based Microwave Synthesis and Optical Characterization of Anisotropic Gold Nanoparticles

Anisotropic gold nanoparticles (AuNPs) were synthesized using microwave (MW)-assisted route. Lemon extract was used as both reducing and stabilizing agent. Subsequent UV treatment was carried out to modify the particle size and shape. Distribution of triangular and pentagonal-shaped particles were found to increase in number. Moreover, up to 60% increase in particle size was also observed. Change in optical property and appearance of plasmon modes were clear indication of the modification caused. Local density of photonic states (LDOS) and electric field distribution were obtained through computational simulation using MATLAB toolbox. Experimental results were used as the input values for the simulation. Dipolar distribution was observed along the boundaries of the spherical NPs, while for triangular and pentagonal-shaped NPs, they were found to be concentrated along their edges and corners. The results presented here encourage us to choose an alternative eco-friendly, quick and simple route to synthesize gold NPs of various shapes for various application such as in viral detection, nanobiomaterials, biomedical images, detection-therapy, etc.

Biological activity of silver nanoparticles synthesized with Paenibacillus polymyxa exopolysaccharides

Recently, there has been increased interest in the synthesis of nanoparticles by using natural polysaccharides. These polysaccharides are eco-friendly, nontoxic, and cheap to prepare. On the other hand, the attention in hydrocolloids and films has significantly enhanced, and their application is very promising in the food, pharmaceutical, perfumery and cosmetics, oil, paper, and textile industries. In this context, the present study is aimed to prepare silver nanoparticles by using viscous and superviscous exopolysaccharides of the rhizobacterium Paenibacillus polymyxa strains, CCM 1465 and 88A, and examined the properties of the resultant nanoparticles. We examined the synthesis and properties of silver nanoparticles under variable synthetic conditions by using exopolysaccharides of the rhizobacteria Paenibacillus polymyxa CCM 1465 and 88A. To prepare nanoparticles, we used different combinations of exopolysaccharide and silver nitrate concentrations: 1–10 mg/mL and 1–40 mM, respectively. The resulting solutions were alkalinized from pH 7.5–12 and heated for 15, 30, and 60 min to determine the optimal synthetic conditions. We found that the exopolysaccharides of strains CCM 1465 and 88A reduced silver ions and acted as nanoparticle stabilizers. The prepared spherical, oval, and triangular particles were stable and ranged in size from 2 to 40 nm, depending on the strain and on the experimental conditions. The nanoparticles showed antibacterial and antifungal activity against Escherichia coli K-12, Pseudomonas aeruginosa 50.3, Bacillus subtilis 26-D, and Fusarium oxysporum. In addition, the nanoparticles were active against SK-MEL-2 human melanoma cells. This finding shows the promise of further research on the exopolysaccharides of P. polymyxa 1465 and 88А in different fields of science, including medicine.

Tailoring Room Temperature Ferromagnetism and Observation of Electrolyte of Widest Potential Window in Gd0.75Se Nano Particles

AbstractUniformly distributed rectangular nanoparticles with some triangular particles of gadolinium selenide (Gd0.75Se) are prepared by the chemical precipitation method. It crystallizes in a cubic structure. It shows paramagnetic behavior along with interesting weak ferromagnetism at room temperature. In the present study, the cyclic voltammogram of electrolyte of Gd0.75Se shows pseudocapacitive behavior with a wider potential window of 3.75 V. The wider potential window electrolyte enhances applications in the super capacitor field for energy storage. The specific capacitance is 21 F g−1, and the energy density is 146 Wh kg−1. The observed high power density is 4.2 kW kg−1. The energy gap is 1.55 eV. A study of photoluminescence confirms the presence of native point defects.

Study on the Variation Characteristics of the Average Velocity of Special-Shaped Flake Particle Systems Moving in Elliptical Drums

Researching the moving speed of particles in a drum is helpful to the optimal design of the rotating device. In this paper, the average mixing velocity of flake particles with different shapes in an elliptical drum is studied. In detail, the mixing systems of rectangular, triangular, and circular flake particles and circular particles are studied; the rollers with different eccentricities are studied; the velocity and periodic variation characteristics of the particle system at 15 rpm and 45 rpm are compared and analyzed; the variation curves of particle average velocity, velocity peak fitting curve (PFC), velocity trough fitting curve (TFC), and velocity fitting under various working conditions are drawn. The results show that the average velocity fluctuation range of the particle system increases gradually with the increase of the eccentricity of the rotating device and the volume of flake particles; the fluctuation of particle average velocity fitting curve and PFC curve in the elliptical drum has a certain cycle, while the fluctuation of the above two curves in the circular rotary device has almost no cycle.

Numerical simulations of polygonal particles settling within non-Newtonian fluids

The settling of circular and polygonal particles within non-Newtonian fluids is investigated by combining the lattice Boltzmann method (LBM) and the discrete element method (DEM). The immersed moving boundary (IMB) scheme with good numerical stability is adopted to couple LBM and DEM. To efficiently calculate the solid coverage ratio in IMB, a novel method is developed, which simply involves judging whether the square is fully occupied by the particle and subdividing the square crossed by the fluid–solid boundary. After validations, the drafting–kissing–tumbling dynamics of two particles settling in the Newtonian and power-law fluids are studied first. It shows that the shear-thickening fluid has a longer kissing duration than the Newtonian and shear-thinning fluids. The kissing duration of squared particles (0.29–0.41 s) is shorter than triangular particles (0.32–0.84 s) and much shorter than circular particles (0.61–0.98 s). Then, the settling of multiple and multi-shape particles in a closed cavity is analyzed. The disturbed area of kinematic viscosity induced by particle motion in the shear-thinning fluid is 21.0–22.5 cm2, significantly larger than in the shear-thickening fluid (10.1–10.8 cm2). Circular particles have a larger disturbed area than the polygonal particles due to the larger settling velocity. Moreover, compared with the Newtonian and shear-thinning fluids, the shear-thickening fluid has a smaller vertical length of particle cluster, meaning a positive influence on the agglomeration of particles.

Thermofluid characterization of nanofluids in spray cooling

The current study addresses a parametric characterization of nanofluid sprays as a way to improve the thermal performance of spray cooling systems. The nanofluids are prepared using as base solution of distilled water with 0.05% (m/m) cetyltrimethylammonium bromide – CTAB in which nanoparticles of alumina and silver are mixed at different concentrations, namely 0.5%, 1% and 2% (m/m). The effect of the shape of the nanoparticles is also considered. These nanofluids are sprayed using a pressure-swirl atomizer and impact, vertically at two different heights, onto an AISI 304 stainless steel foil. This foil is heated by Joule effect, with two imposed currents, delivering 915 and 2100 W/m2. Infrared thermography is used to measure the thermal footprint from which the dissipated heat flux is calculated. Results show that, in steady state operation, the lowest surface temperature is obtained with the 0.5% (m/m) alumina nanofluid, while increasing alumina nanoparticles, concentration increases the radial temperature distributions on the surface. Results also show a mild effect of the shape of the nanoparticles. Hence, lowest surface foil temperatures are achieved with the silver nanofluid with spherical particles, when compared with the same nanofluid with triangular particles. Heat transfer coefficients decreased with increasing thermal conductivity and dynamic viscosity of the nanofluids. On the other hand, a positive correlation is found between the specific heat capacity of the nanofluids and the spray cooling capacity. For the range of experimental conditions covered in this work, nanofluids have proven to increase the thermal performance of the spray.

Synthesis of the S/AgBr nano/micropowder in DMSO-water system

A new synthesis method of S/AgBr nano/micropowder based on sulfur and silver halide was developed. The nano/micropowder was obtained in the DMSO-water system, in two stages. Initially, sulfur was dissolved in DMSO at 120°C. The resulting solution was cooled to room temperature and separated from sulfur by filtration. Then, pre-prepared water solutions of AgNO3 and NaBr were introduced drop by drop into a sulfur solution in DMSO, at room temperature. The phase composition and structure of the precipitated powdery sediment were studied by X-ray diffraction analysis (XRD) and Raman spectroscopy. Scanning electron microscopy (SEM) was used to study the morphology and particle size. XRD showed the presence of the crystalline phase of AgBr, while the Raman spectra were characterized by the presence of sulfur and AgBr peaks. The SEM results showed that the S/AgBr is represented by oval, spherical and triangular particles of a homogeneous structure; the particle size was in the range from 300 to 800 nm.

Effect of Geometrical Properties on Localized Surface Plasmon Resonance of Gold Nanoparticles

This work reportson plasmonic effects (i.e light scattering and absorption properties) induced by two different gold nanoparticles (AuNPs)-shaped: spherical particle and triangular particle. The scattering cross-section and electric field profiles have been investigated by using theboundary element method (MNPBEM toolbox). Two configurations: the isolated AuNPand the coupledtwo-gold NPsystem have been considered to evaluate the localized surface plasmon resonance (LSPR) in eithersingle or coupled AuNPstructures. The effect of the surrounding medium on the scattering behavior of the NPs has also been examined. Then the dependence of “hotspot” intensity on the distance between two NPs has been recognized by mapping the electric field profile. The obtained results can be used as the guidelines for synthesizing AuNP structures to employ LSPR for sensing or other applications.

Dynamic soft sensor modeling method fusing process feature information based on an improved intelligent optimization algorithm

The lack of real-time and accurate melting index forecast model puts forward challenges to the online quality detection and control of the polypropylene industrial production. Meanwhile, the key process characteristics of dynamic and time delay are not fully and effectively integrated into the soft sensor model. Therefore, a novel dynamic soft sensing (DSS) modeling method using the orthogonal echo state network (OESN) based on the cumulative mutual information (CMI) threshold setting integrating an improved differential evolution algorithm (IDE) (OESN-CMI-IDE) is proposed. The mutual information of each candidate auxiliary variable relative to the dominant variable is calculated and sorted to determine the CMI threshold and select the corresponding auxiliary variable. Then an IDE algorithm is used to optimize the parameters of the OESN model, which has faster convergence, higher accuracy and stronger robustness than that of DE, self-adaptive DE (jDE), DE with time varying scale factor (DETVSF), line decreased inertia weight particle swarm optimization (LDPSO), flexible exponential inertia weight particle swarm optimization (FEPSO), and oscillating triangular inertia weight particle swarm optimization (OTPSO) in terms of evolutionary computing competition benchmark function tests. Finally, the proposed method is applied to predict the melt index in an actual polypropylene plant. The experimental results demonstrate that the prediction effect of the proposed method is better than that of the OESN model optimized by DE, jDE, DETVSF, LDPSO, FEPSO, OTPSO and the OESN model without optimization, which can escort the online monitoring and advanced control of the melt index in the propylene industry.

Colloidal Particles with Triangular Patches.

Self-assembling colloidal particles into clathrate hydrates requires the particles to have tetrahedral bonds in the eclipsed conformation. It has been suggested that colloidal particles with eclipsed triangular-shaped patches can form clusters in the eclipsed conformation that leads to colloidal clathrate hydrates. However, in experiments, patches have been limited to circular shapes due to surface energy minimization. Here, we extend the particle synthesis strategy and show that colloidal particles with triangular patches can be readily fabricated by controlling the viscosity of the liquid oil droplets during a colloidal fusion process. The position, orientation, curvature, shape, and size of the patches are all exclusively determined by the intrinsic symmetry of the colloidal clusters, resulting in dipatch particles with eclipsed patches and tetrahedral patchy particles with patch vertices pointing toward each other. Patch curvature can be controlled by tuning the viscosity of the oil droplets and using different surfactants. Using strain-promoted azide-alkyne cycloaddition, single-stranded DNA can be selectively functionalized on the patches. However, after annealing these particles, dipatch particles form chains because the patches are too small to form clathrate hydrates. Under certain conditions, tetrahedral triangular patchy particles should prefer the eclipsed conformation, as it maximizes DNA hybridization. However, we observe random aggregates, which result from having triangular patches that are too big. We estimate that tetrahedral patchy particles that can crystallize need to be less than 1 μm in diameter.

A simple method to design interaction potentials able to generate a desired geometrical pattern

The ability to tailor effective interactions at the molecular level to provide a platform to create advanced functional materials is a challenge for the scientific community. The main goal is to develop a good interaction potential model driving the formation of a given set of target structures. In this work, we propose a simple method to design interaction potentials able to generate a desired geometrical pattern. The methodology combines the Ground State Energy (GSE) method with simulation techniques. To illustrate the method we explored a subfamily of square-shoulder + square well potentials, our target are square and triangular particle arrays. We found that the GSE method predictions were qualitatively correct at non-zero temperatures. The proposed methodology allowed us to build the phase diagram of one member of this family of potentials that exhibits: vapour, liquid, and different crystalline lattices (triangular, square, rhomboid). We show that the GSE method is a powerful and inexpensive computational tool to test the viability of the desired particle array at zero-temperature and also as an initial step to design phase diagrams of model potentials.

The eggshell structure in apteryx; form, function, and adaptation.

Apteryx is a genus of flightless birds endemic to New Zealand known to lay very large eggs in proportion to body weight. The eggshell of Apteryx is unusually thin and less porous than allometrically expected possibly as a compensation for a very long incubation period. Past studies have been carried out on Apteryx australis, a species which once comprised all kiwi with brown plumage, now separated into three distinct species. These species use different habitats and live at different latitudes and altitudes, therefore generating a need to revise our knowledge of the attributes of their eggshells. In this study, we measured the physical characteristics and water conductance on eggshell fragments of these three species and Great‐spotted Kiwi and relate them to the environmental conditions of their respective environments; we also measured the water vapor conductance of Brown Kiwi eggs of late stages of incubation. We found that several trade‐offs exist between incubation behavior, environmental conditions, and eggshell structure. We found differences between species in eggshell water vapor conductance seemingly related to altitude; Brown Kiwi and Rowi generally inhabiting lower altitudes had the highest conductance and Tokoeka, generally living in montane environments, the lowest. This is achieved by an increased eggshell thickness rather than a pore area reduction. Finally, the water vapor conductance late in incubation was 58% higher than infertile unincubated eggs, suggesting a drastic increase in conductance throughout the long incubation period. Using the values previously reported, we calculated the embryonic eggshell thinning to be 32.5% at the equatorial region of the eggshell. We describe several new features, such as triangular mineral particles in the cuticle, reported for the extinct Trigonoolithus amoei, and confirmed the existence of plugged pores. We suggest that these structures provide microbial protection needed by a burrow nesting species with a long incubation period.