Rectangular Particles Research Articles

Visible Light Driven Defect Mediated Photocatalytic Activity of Spray Pyrolyzed Ga and Al Doped ZnO Thin Film Electrodes

AbstractGa and Al doped ZnO thin film electrodes are spray deposited and explored for photocatalytic deterioration of methylene blue dye. X‐ray diffraction unveils both films to have highly textured growth along the (002) plane. The surface morphology is found to have near spherical and distorted rectangular particles for Ga and Al dopants, respectively. Photoluminescence emission study reveals that both films have visible light emissions in the violet, blue, and green regions due to oxygen vacancy defects. The deposited films exhibit a reasonably higher transmittance of 89 and 77 % with mobility of 30.5 and 29.6 cm2/Vs for Ga and Al doped ZnO, respectively. Cyclic test and photo‐corrosion studies performed for selected samples were indicating significant stability. Based on these findings the electrodes are explored for the photocatalytic degradation of methylene blue dye and are found to have significant efficiency upon LED and sunlight irradiation.

Ultra-subwavelength rect-particles for wideband phase velocity equalization in coupled lines

This paper presents a procedural approach for utilizing ultra-subwavelength rectangular chiral particles embedded in the substrate to eliminate the spurious response of the coupled transmission lines by equalizing the even and odd mode phase velocities in a large bandwidth, making it applicable to wideband coupled-line based structures. Even and odd mode phase velocities, is equalized with the BW of 4 GHz, spanning the range 0.5–4.5 GHz, the normalized phase velocity Root Mean Square Error is less than 0.005.

Label-free biosensor on chip (BoC) based on localized surface plasmon resonance for monitoring temperature and blood hemoglobin concentration

On-chip localized surface plasmon resonance (LSPR) biosensor on chip (BoC) is a type of label-free biosensor that utilizes the plasmonic resonances of metal nanostructures to detect changes in the refractive index of the local environment. This results in changes in the intensity and wavelength of the surface plasmon resonance, which can be used to quantify the presence and concentration of biomolecules such as proteins, nucleic acids, and cells. In this paper, we propose a novel on-chip device with a microfluidic channel that contains the biological fluid under test. We have obtained sharp resonance peaks in the wavelength range between 700–800 nm with a sensitivity of 509 nm R−1IU−1 which is good compared to other on-chip devices. The main advantage of our design is the less complex manufacturing process compared to other BoCs. Our design consists of a central cavity that is surrounded by silver and consists of rectangular pillar-shaped silver particles placed in the cavity. Two very promising applications of this device are label-free temperature sensing and blood hemoglobin (Hb) concentration sensing with a resolution of 0.222 nm/°C for temperature and 1. 34 nm/(g/dL) for Hb. However, it can be used for any kind of sensing application that involves refractive index changes as the sensing platform.

Histopathologic and transmission electron microscopic findings in monkeypox cutaneous lesions.

a few pathologic and ultrastructural findings of monkeypox skin lesions are available in the literature. To integrate such evidence, we aimed to describe the pathologic features of monkeypox skin lesions and to show monkeypox virions by transmission electron microscopy (TEM). we studied the cutaneous biopsies of three patients affected by monkeypox during the 2022 monkeypox outbreak. Skin biopsies have been collected only from body sites with a recent laboratory-confirmed mpox virus infection, defined by a polymerase chain reaction (PCR) positive result in specimens taken through skin swabs. in all the samples the epidermis showed keratinocytes ballooning degeneration; perivascular/periadnexal infiltrates composed of neutrophils and lymphocytes were observed in the deep dermis. Immunohistochemistry showed that the infiltrate was mostly composed of CD3+ T-cells. TEM revealed monkeypox virus-like particles in various stages of morphogenesis in the dermis and epidermis; virions were interspersed among keratinocytes and within their cytoplasm. At the intracellular level, virions showed a biconcaveshaped central core, surrounded by lateral bodies and an external membrane; they also appeared as rectangular, brick-shaped, or oval particles with eccentric nucleoids. The histologic features of our skin samples confirmed the few other studies on this topic, except for the eosinophilic inclusions of the cytoplasm of keratinocytes (Guarnieri's bodies). the role of molecular biology is crucial for monkeypox diagnosis but when it is not disposable and/or in doubtful cases, skin biopsy and TEM may be helpful to establish the diagnosis.

Synthesis, spectroscopy, band gap energy and electrical conductivity of poly(dopamine–co–aniline) copolymer

Copolymerization is used to improve the solubility and processability of polymers and copolymers includes the individual properties of homopolymer. In this study, the poly(dopamine-co-aniline) (poly(DA-co-ANI) copolymer was synthesized and the UV–vis. absorption, optical band gap energy, fluorescence, FT-IR, SEM-EDS, MALDI-TOF-MS, XRD and electrical conductivity have been investigated. The obtained results for the poly(DA-co-ANI) copolymer were compared with the PDA and PANI homopolymers. It was observed that the poly(DA-co-ANI copolymer is soluble easily in NMP and DMF solvents. The optical band gap energy of the poly(DA-co-ANI) copolymer film were calculated. as 1.00 eV with favorable indirect transition. The poly(DA-co-ANI) copolymer showed the FL emission maximum bands at 390 and 533 nm wavelengths. It was observed from the SEM images that the poly(DA-co-ANI) has 0–1500 nm crystalline rectangular particles prepared in acidic media and 0–600 nm amorphous particles prepared in basic media. The electrical conductivity of the poly(DA-co-ANI) was 1.35 × 10−6 S/cm. In the MALDI-TOF-MS measurements, the number-average molecular weight of the copolymer was found as 2628 Da with a distribution up to 5500 Da. The poly(DA-co-ANI) copolymer, soluble in NMP and DMF solvents and with a low optical band gap energy can be utilized as optical, fluorescent, and semi-conductive material in biomedical applications.

Multistate Dynamic Pathways for Anisotropic Colloidal Assembly and Reconfiguration.

We report the controlled interfacial assembly and reconfiguration of rectangular prism colloidal particles between microstructures of varying positional and orientational order including stable, metastable, and transient states. Structurally diverse states are realized by programming time dependent electric fields that mediate dipolar interactions determining particle position, orientation, compression, and chaining. We identify an order parameter set that defines each state as a combination of the positional and orientational order. These metrics are employed as reaction coordinates to capture the microstructure evolution between initial and final states upon field changes. Assembly trajectory manifolds between states in the low-dimensional reaction coordinate space reveal a dynamic pathway map including information about pathway accessibility, reversibility, and kinetics. By navigating the dynamic pathway map, we demonstrate reconfiguration between states on minute time scales, which is practically useful for particle-based materials processing and device responses. Our findings demonstrate a conceptually general approach to discover dynamic pathways as a basis to control assembly and reconfiguration of self-organizing building blocks that respond to global external stimuli.

Impact of grain geometry on chlorohydrocarbon contaminant transformation and reductive dichlorination activity

Porous media widely exists in natural aquifers, engineering materials (such as materials used to remove contaminants from water) and oil reservoirs, etc. Due to the complexity of particles contained in porous media, the fluid flow and contaminants transport are undoubtedly affected by the particle geometry of porous media. Two kinds of particle geometry models are developed to assess whether the geometry of grain plays an important role on chlorohydrocarbon contaminant transport and bioremediation. Porous medium properties such as tortuosity, permeability and entry pressure are quantified for the two kinds of particle geometries. Meanwhile, a laboratory experiment for perchloroethylene (PCE) transport is performed in a two-dimensional (2D) sandbox to verify permeability and entry pressure derived by different particle geometries. Comparison between geometry models and experimental results indicate rectangular particles (RP) with high μ (the ratio of width to length) and ellipse particles (EP) with low η (the ratio of semi-long axis to semi-shorter axis) agree well with the experiment. Moreover, the grains geometry that forms the porous matrix's solid domain applied in the experiment is also identified according to the numerical simulation of PCE migration. Furthermore, two kinds of particle geometries are coupled with UTCHEM, to derive the effects of particle geometry on Trichloroethylene (TCE) transport, redistribution and biodegradation by methanotrophs for a realistic three-dimensional (3D) aquifer application. Results suggest the geometry of grain has a significant influence on the properties of a porous medium. The remediation efficiency became higher when μ increased for RP and η decreased for EP. PCE infiltration rate was lowest for RP with high μ and EP with low η. Simulation results based on realistic groundwater bioremediation indicated RP with μ = 0.9, EP with η = 1.1 and EP with η = 1.3 achieved the highest bioremediation efficiency for TCE contamination.

Removing antibiotic resistance genes through the synergistic effect of hydroxyl radical and hypochlorite radical generated in a CeO2@CNT electrified membrane – NaClO system

The removal of antibiotic resistance genes (ARGs) is important for inhibiting the spread of antibiotic resistance in the aquatic environment. In this study, a series of coupled advanced oxidation-disinfection systems were developed based on a carbon nanotube membrane modified with different CeO2 nanocrystals and NaClO (denoted as CeO2@CNT-NaClO system). The removal performance of ARGs by the CeO2@CNT-NaClO systems was tested by treating the simulated water samples containing Pseudomonas sp. HLS-6 with sul1 genes and Escherichia coli TOP10F with tetA genes. The results showed that the CeO2@CNT-NaClO system showed the superior disinfection efficiencies compared to using sole CeO2@CNT electrified membrane and sole NaClO. After treatment by the CeO2@CNT-NaClO system, Pseudomonas sp. HLS-6 and Escherichia coli TOP10F were completely inactivated, and the absolute abundances of sul1 and tetA genes decreased by 4.8 log and 1.8 log, respectively. The probe compounds and quenching experiments showed the synergistic effect of •OH and •ClO is the main contributor to the high removal efficiencies of ARGs by the CeO2@CNT-NaClO system. The rectangular CeO2 particles with (200) and (111) crystal facets exhibited the largest amounts of oxygen vacancy and Lewis acid sites, which favored the coupled system to generate the highest cumulative concentration of •OH and •ClO. This led to a synchronous high-efficiency removal of ARGs and antibiotics in the CeO2@CNT-NaClO system.

Simulation and verification of particle flow with an elastic collision by the immersed edge-based smoothed finite element method

The immersed edge-based smoothed finite element method (IES-FEM) is proposed for the study of elastic collision particulate flow. Particle collision becomes more realistic by using the penalty function and the hyperelastic constitutive model. The effects of grid resolution and Reynolds numbers on particle terminal velocity and drag coefficient are discussed to verify the calculation accuracy and stability. Single-particle collisions with the bottom and side walls are analyzed and experimentally verified. Results show that the calculation error of IES-FEM is less than 0.6% when the fluid grid size is 0.5 times the particle mesh size and the time step is 10–4 s. Particle drag coefficient and flow characteristics agree well with the published models and experiment results. To demonstrate the capabilities of IES-FEM in complex elastic particle systems, the collision and rebound of multiple particles are determined, including the drafting–kissing–tumbling of two circular particles; the chase, collision, and deformation of rectangular particles; and the repeated formation and separation of particle clusters. This work extends the application of IES-FEM in particle-resolved direct numerical simulation methods, which will provide an optional tool for future elastic blood cell flow and collision.

Influence of 3-aminopropyltriethoxysilane/tetraethylorthosilicate mixture pretreatment on the microstructure and corrosion resistance of zeolite coating

ABSTRACT The influence of silane pretreatment with five different volume ratios (100/0, 75/25, 50/50, 25/75, and 0/100) of 3-aminopropyltriethoxysilane (APTES)/tetraethylorthosilicate (TEOS) on microstructure and corrosion resistance of the hydrothermal synthesized zeolite coatings on the H13 steel substrates was investigated. The surface of the zeolite coatings on the 100/0, 75/25, and 50/50 mixture of the APTES/TEOS pretreated substrates was composed of intergrown rectangular particles. Additionally, pores were observed. A 25/75 mixture of APTES/TEOS pretreatment smoothed the edges and angles of zeolite particles with gel-like materials filled in the pores. In pure TEOS pretreatment, microcracks, and much gel-like materials were observed on the zeolite coating. The electrochemical test revealed that the zeolite coating on a 50/50 mixture of the APTES/TEOS pretreated substrate exhibited the highest corrosion resistance in 3.5 wt-% NaCl solution. This was because a 50/50 mixture of APTES/TEOS pretreatment advantageously promoted development of a dense and thick gel layer, which enhanced the intergrowth of zeolite particles.

Efficient Removal of Lead(II), Cadmium(II) and Zinc(II) from Aqueous Solutions by Bis[2‐(1H‐benzimidazol‐2‐il)phenyl]disulfide, a Solid Chelating Agent

AbstractThe bis[2‐(1H‐benzimidazol‐2‐yl)phenyl]disulfide [bis(2phSbz)] was characterized by SEM, nitrogen adsorption and desorption, PXRD, and TGA analysis. It was evaluated as a solid chelating adsorbent to remove lead(II), cadmium(II), and zinc(II) ions from aqueous solutions. Bis(2phSbz) consists of agglomerated, rectangular particles of non‐uniform size, lacking porosity and roughness. Metal ion sorption is pH dependent. The equilibrium data are described by the Langmuir model, while the pseudo‐second‐order model fits metal ions′ adsorption kinetics best. The maximum adsorption capacities for lead(II), cadmium(II), and zinc(II) were 543.82, 482.56, and 306.96 mg/g, respectively. In a competitive test, bis(2phSbz) was found to be able to selectively remove lead(II) from multicomponent solutions. Desorption efficiencies higher than 65 % can be achieved using EDTA 0.1 M as a desorption agent. From a theoretical standpoint, we corroborate the experimental results in terms of some significant quantum mechanics descriptors. Bis(2phSbz) may be a novel and potentially valuable chelating adsorbent for lead(II) removal.

Effects of the inlet particle spatial distribution on the performance of a gas-solid cyclone separator

The present study was aimed at the inlet particle spatial distribution of a gas-solid separator with high solid loading and investigated its effects on cyclone performance and the inner flow pattern. The flow fields of a cyclone with different rectangular particle flow areas on the inlet surface were numerically simulated using a four-way coupling method. The simulated results indicate that reducing the inlet particle flow area and lowing the inlet particle position can effectively reduce the scattered particles inside the cyclone separator and enhance the separation performance. Vertically gathering the particles to the centerline can also weaken the particle back-mixing. The particles near the roof account for the swirling particle ceiling phenomenon. The inlet particle spatial distribution affects the pressure drop mainly by affecting the gas tangential velocity in the cylinder body. Moreover, compared to the horizontal particle distribution on the inlet surface, the vertical particle distribution has greater effects on cyclone performance.

Self-organizing single-line particle trains with differently shaped particles in a channel flow

The inertial migration of differently shaped rectangular particles and elliptical particles in a channel flow and the self-organization of single-line particle trains are studied using the lattice Boltzmann method. The effects of particle shape, particle aspect ratio (α), Reynolds number (Re), blockage ratio (k), and particle concentration (Φ) on self-organizing single-line particle trains are explored. The results show that a single-line particle train is dynamically formed, with circular particle trains having a more pronounced dynamic process than rectangular and elliptical particle train. The inclination of height (IH) for the particles in the train is the main reason for the dynamic formation of a single-line particle train. Due to the changes of orientation angle under different flow conditions, the rectangular particle trains always have a larger IH and smaller interparticle spacing than the elliptical particle trains when the train is just formed. The effect of α on the spacing of elliptical particle trains is more sensitive than other shapes. Rectangular particles and elliptical particles with large Φ and Re and small k are prone to self-organize the single-line particle trains with stable spacing for a long travel distance. With increasing Φ, Re, and k, IH increases and the interparticle spacing decreases.

Lateral Migration of Variously Shaped Particles: A Computational Study

AbstractThe current work deals with the simulation of lateral migration of differently shaped particles in a straight channel through which fluid flows with a Poiseuille pattern of flow. The immersed boundary method based on feedback force is adopted for the current work. The equilibrium positions and migration times for circular, elliptical, rectangular, square, and biconcave particles are studied and presented. The cases of neutral and massive (high ratio of particle density to fluid density) particles are presented, and in both scenarios the biconcave particle attains its equilibrium position closest to the bottom wall and the elliptical particle acquires its equilibrium position closest to the channel center. Also, the migration time is highest for the biconcave particle, whereas it is lowest for the rectangular particle.

The effects of particle shape on inertial focusing

This paper proposes a 2D particle inertial focusing model by the immersed boundary–lattice Boltzmann method (IB-LBM), aiming to study the effects of particle shapes on their focusing state. First, as the validation, we investigated the inertial focusing of circular particles and got consistent focus positions with other previous reports. Then, the inertial focusing of the circle, rectangle, ellipse, and capsule particles were studied in detail. The results revealed that the particle shapes significantly influence the focusing positions, self-rotation, and running speed. At a given Reynolds number, the circular particle has a minimum average distance to the pipe center in the focus state, then follows the elliptical, capsular, and rectangular particles. The elliptical particle’s self-rotation cycle is in approximately the cubed relation to the long-short axis ratio. Moreover, the rectangle particle runs fastest at the same Reynolds number, followed by capsule, ellipse, and circle particles. Our study and the above results can provide a significant reference for screening or separating particles with different shapes in microfluidic devices.

Effect of Ratio of Divergent to Parallel Length in Rectangular Cross Section Nozzle and Particle Size on Spray Pattern of Copper Coating by High Pressure Cold Spray

Effect of Ratio of Divergent to Parallel Length in Rectangular Cross Section Nozzle and Particle Size on Spray Pattern of Copper Coating by High Pressure Cold Spray

Effect of various morphology of in situ generated NbC particles on the wear resistance of Fe-based cladding

To improve the wear resistance of Fe-based cladding, NbC particles with different morphology are generated in situ by adding Nb, Cr3C2 and C with different content. The composition of samples and the morphology of NbC particles generated in situ are revealed by XRD, SEM and EDS. The wear resistance is studied by a reciprocating friction and wear testing machine. The wear mode and the wear mechanism of each sample are investigated. The results show that although NbC particles are generated in situ in samples with different Nb, Cr3C2 and C content, the morphology of NbC particles is varied. The wear resistance of samples containing cross-shaped NbC particles is more outstanding than that of samples containing only rectangular NbC particles. In addition, changing Nb, Cr3C2 and C content does not result in a change in wear mode, but leads to the formation of continuous lattice structure of Cr0.19Fe0.7Ni0.11 and Cr23C6 compounds at grain boundaries and a change in the wear resistance. When the additions of Nb, Cr3C2 and C are 11.2 wt%, 8.6 wt% and 0.2 wt% respectively, the coefficient of friction of the sample is the lowest, and the wear resistance is the most outstanding.

GeoBioMed perspectives on kidney stone recurrence from the reactive surface area of SWL-derived particles

Shock wave lithotripsy (SWL) is an effective and commonly applied clinical treatment for human kidney stones. Yet the success of SWL is counterbalanced by the risk of retained fragments causing recurrent stone formation, which may require retreatment. This study has applied GeoBioMed experimental and analytical approaches to determine the size frequency distribution, fracture patterns, and reactive surface area of SWL-derived particles within the context of their original crystal growth structure (crystalline architecture) as revealed by confocal autofluorescence (CAF) and super-resolution autofluorescence (SRAF) microscopy. Multiple calcium oxalate (CaOx) stones were removed from a Mayo Clinic patient using standard percutaneous nephrolithotomy (PCNL) and shock pulse lithotripsy (SPL). This produced approximately 4–12 mm-diameter PCNL-derived fragments that were experimentally treated ex vivo with SWL to form hundreds of smaller particles. Fractures propagated through the crystalline architecture of PCNL-derived fragments in a variety of geometric orientations to form rectangular, pointed, concentrically spalled, and irregular SWL-derived particles. Size frequency distributions ranged from fine silt (4–8 μm) to very fine pebbles (2–4 mm), according to the Wentworth grain size scale, with a mean size of fine sand (125–250 μm). Importantly, these SWL-derived particles are smaller than the 3–4 mm-diameter detection limit of clinical computed tomography (CT) techniques and can be retained on internal kidney membrane surfaces. This creates clinically undetectable crystallization seed points with extremely high reactive surface areas, which dramatically enhance the multiple events of crystallization and dissolution (diagenetic phase transitions) that may lead to the high rates of CaOx kidney stone recurrence after SWL treatment.

Study of Micro-Parameters of DEM Model on the Laboratory Experiment Results Obtained from Poorly Cemented Sandstone

Borehole convergence during or after drilling is one of the primary indicators of borehole instability. Early recognition of borehole instability is critical in achieving successful and timely completion of drilling operations and for borehole exploitation. A series of numerical simulations was conducted to investigate the borehole convergence of poorly cemented sandstones using the Discrete Element Method (DEM). Rectangular 2-dimensional Particle Flow Code 2D (PFC2D) models were generated to study the effect of contributing micro-parameters such as stiffness ratio, friction angle, friction coefficient and effective modulus on the behaviour of poorly cemented sandstone subjected to triaxial compression tests. A good agreement between the calibrated numerical models and the experimental data obtained from the laboratory was observed. The results showed that the stiffness ratio was found to be a dominant factor in calibrating the numerical model, and the friction coefficient was the most influential micro-parameter.

Effect of particle morphology on fatigue crack propagation mechanism of TiB2-reinforced steel matrix composites

Fatigue crack growth mechanisms of as-cast and hot-rolled TiB2-reinforced steel matrix composites (SMCs) fabricated by eutectic solidification are systematically investigated through in-situ scanning electron microscopy (SEM) fatigue experiment system. The experiment results show that the as-cast SMC exhibits a relatively superior fatigue crack growth resistance with respect to the hot-rolled SMC. A lower FCGR at the low and intermediate stress intensity factor (ΔK) range in as-cast SMC is found, which is related to the TiB2 particle morphology. Hexagonal and rectangular primary particles have a high Young’s modulus and strong interfacial bonding, which inhibits the advancing of plastic deformation in front of the crack tip. Three-dimensional interconnected eutectic particle phases composed of dendrites can produce a hardening effect at crack tip and restrain the generation of plastic deformation in this morphology region. The stress-strain field in front of the crack tip is changed by the hard TiB2 particles, which leads to the deflection of the crack path. Hence, the tortuous crack path created by facing these particles causes reduction in the effective driving force of the crack tip and slows the FCGR. The net mismatch between the surfaces lead to premature contact and roughness-induced crack closure further reducing the FCGR. In comparison, large number of hot-rolled micro-cracks in the hot-rolled SMC are detrimental to fatigue crack growth resistance through the coalesce mechanism of micro-cracks, thereby accelerating the FCGR.