Particle Morphology Research Articles

Morphology, aspect ratio, and surface elemental composition of primary aerosol particles at urban region of India.

The PM2.5 and PM10 particles were characterized in terms of morphology (size and shape) and surface elemental composition at two different (traffic and industrial) locations in urban region of India and further linked to different morphological defining parameters. The overall PM2.5 and PM10 showed significant daily variability indicating higher PM10 as compared to PM2.5. PM2.5/PM10 ratio was found to be 0.58 ± 0.10 indicating the abundance of PM2.5. Soot aggregates, aluminosilicates, and brochosomes particles were classified based on morphology, aspect ratio (AR), and surface elemental composition of single particles. The linear regression analysis indicates the significant correlation between area equivalent (Daeq) and feret diameter (Dfd) (R2 0.86-0.98). Higher aspect ratio (1.48 ± 0.87-1.43 ± 0.50) was noted at traffic site as compared to industrial site (1.33 ± 0.58-1.29 ± 0.30), while circularity showed the opposite trend. Fractal dimension (Df) of soot aggregates estimated by the soot parameters method (SPM) were found to be 1.70, 1.72, and 1.88, mainly attributed to vehicular emissions, biomass, and industrial emission/coal burning, respectively. This further inferred that freshly emitted soot particles exhibited lacey in nature with spherical shape (Df 1.70) at traffic site, while at industrial location, they were different with compact shapes (Df 1.88) due to particle aging processes. This study inferred the synoptic changes in mass, chemical characteristics, and morphology of aerosol particles which provide the new insights into individual atmospheric particle and their dynamic nature.

Quinacridones as a Building Block for Sustainable Gliding Layers on Ice and Snow.

Quinacridone (QA) and 2,9-dimethylquinacridone (DQA) are synthetic substances suitable as a hard, abrasion-resistant, self-organizing gliding layer on ice and snow. For sustainable use, a large number of parameters must be considered to demonstrate that these non-biogenic substances and their by-products and degradation products are harmless to humans and the environment in the quantities released. For this task, available experimental data are used and supplemented for all tautomers by numerous relevant physical, chemical, toxicological and ecotoxicological estimated values based on various Quantitative Structure Activity Relationship (QSAR) methods. On the one hand, the low solubility of QA and DQA leads to stable gliding layers and thus, low abrasion and uptake by plants, animals and humans. On the other hand, the four hydrogen bond forming functional groups per molecule allow nanoparticle decomposition and enzymatic degradation in natural environments. All available data justify a sustainable use of QA and DQA as a gliding layer. The assessment of the toxicological properties is complemented by an investigation of the size and morphology of DQA particles, as well as field tests indicating excellent performance as a gliding layer on snow.

A Layered Titanate Nanowire Helps Pt/TiO2 Photocatalyst for Solar Hydrogen Evolution from Water with High Quantum Efficiency

Abstract Research into TiO2 photocatalysts for solar H2 evolution from water is still growing for environmentally benign and economically valid H2 production. Herein, in contrast to many researches on the modification of TiO2 toward higher photocatalytic activities, we develop a photocatalytically inactive TiO2-based nanostructure and use it, like graphene, as a booster of a benchmark TiO2. A layered potassium titanate with two-dimensional plate-like particle morphology was converted to the corresponding one-dimensional nanowire form via a hydrothermal reaction, after which the layered potassium titanate nanowire was acid-treated to obtain a layered titanate nanowire. This nanowire was completely inactive toward H2 evolution from water containing methanol under solar simulator irradiation. However, when Pt nanoparticle-loaded P25 TiO2 (Pt/P25) was mixed with a considerably smaller amount of the layered titanate nanowire in water, a durable composite was obtained and the composite showed a good photocatalytic activity three times higher than Pt/P25. The apparent quantum efficiency of the reaction at wavelength of 350 nm was 56%, which was higher than or comparable to those of the state-of-the-art TiO2-based photocatalysts. The possible reason for the enhanced photocatalytic activity of the Pt/P25 and layered titanate nanowire composite involved the transfer of photogenerated holes from Pt/P25 to the nanowire to suppress charge recombination and/or disaggregation (improved dispersion) of Pt/P25 particles on the nanowire.

Synthesis, characterization, and temperature-dependent luminescence of Tb3+-activated and self-activated Sr10(PO4)6Cl2 phosphors

In this work, a series of new nanosized phosphors based on strontium chlorapatite (Sr10(PO4)6Cl2, abbreviated as SrClAp) with varying terbium concentration were synthesized using a modified microwave-hydrothermal method. This study meticulously investigated the impact of Tb3+ concentration and annealing temperature on factors such as crystal purity, particle morphology, photoluminescence, chromatic properties, and the mechanism of thermal quenching.The synthesized phosphors underwent characterization using X-Ray Diffraction (XRD) and scanning electron microscopy (SEM) to verify their crystal structure purity and examine their morphology. Upon near-ultraviolet (NUV) excitation at the 378 nm line, the obtained nanosized powders emitted green light arising from the characteristic 5D4→7FJ (J = 6, 5, 4, 3) transitions of Tb3+ ions. Notably, a broad host-related emission was discernible at 80 K, with its intensity diminishing as the temperature increased. The mechanism governing this host-related emission and the process of its thermal quenching have been proposed. Moreover, a comprehensive exploration of the influence of ambient temperature on the emission of Tb3+-doped SrClAp was undertaken.

Gas and particle emissions from rifle and pistol firing

Emissions were sampled from firing an M4 carbine rifle and a M9 (military issue of Beretta 75 FS 9 mm pistol) to develop sampling methods and assess potential exposures and range contamination issues. Breech and muzzle emissions were sampled from the rifle when firing M855A1 ammunition (lead (Pb)-free slugs) in single- and triple-shot burst mode and from single pistol shots when firing 9 mm XM1152 ammunition (not Pb-free). Emissions were sampled for carbon monoxide (CO), carbon dioxide (CO2), methane, hydrogen cyanide, ammonia, particulate matter by size, polycylic aromatic hydrocarbons, and volatile organics. Analyses on the particles included elemental composition, size distribution, carbon composition (black, total, organic, and elemental carbon), and particle composition and morphology. Emission concentrations from both the rifle and pistol were characterized by CO/CO2 ratios between, approximately, 1/1 and 2/1, respectfully, indicating incomplete carbon oxidation. The initial particle size distribution was dominated in number by particles smaller than 40 nm but the high particle concentrations led to rapid agglomeration. The abundance of CO and metals of inhalable particle size are noteworthy and indicate that further assessment of exposure would determine potential inhalation health hazards, particularly in indoor firing ranges.

An acoustofluidic picoinjector

Droplet microfluidics has emerged as a valuable technology for a multitude of chemical and biomedical applications, offering the capability to create independent microenvironments for high-throughput assays. Central to numerous droplet microfluidic applications is the picoinjection of materials into individual droplets, yet existing picoinjection methods often exhibit high power requirements, lack biocompatibility, and/or suffer from limited controllability. Here, we present an acoustofluidic picoinjector that generates acoustic pressure at the droplet interface to enable on-demand, energy-efficient, and biocompatible injection at high precision. We validate our platform by performing acid-base titrations by iteratively injecting picoliter volume reagents into droplets to induce pH transitions detectable by color change in solution. Additionally, we demonstrate the versatility of the acoustofluidic picoinjector in the synthesis of metallic nanoparticles, yielding highly monodisperse and reproducible particle morphologies compared to conventional bulk-phase techniques. By facilitating controlled delivery of reagents or biological samples with unparalleled accuracy, acoustofluidic picoinjection broadens the utility of droplet microfluidics for a myriad of applications in chemical and biological research.

Experimental simulation evaluation and control measures of paving segregation for the stone matrix asphalt mixtures

The aggregate segregation for asphalt mixtures, characterized by non-uniform particle distribution, significantly undermines the quality and performance of pavements. This investigation aims to explore and reveal the mechanisms underlying segregation, including raw material properties and construction procedures. Novel evaluation methods, predictive metrics, and control measures were introduced using the developed apparatus. The results indicate that physical properties, particle morphology, and gradation are fundamental factors driving segregation. Spatial hindrance, interfacial friction, collision, and self-organization collectively coordinate particle spatial migration and distribution. Excessive coarse particles induce interstitial displacement, while that of fine particles trigger third-body lubrication. The lubricating-bonding factor η was proposed to characterize asphalt regulation. Segregation prediction based on composite angularity facilitates informed raw material selection. In addition, measures to improve paving quality and efficiency during loading, unloading, and auger mixing were proposed. This research contributes to the understanding of segregation mechanisms, enabling early prevention and effective management strategies.

Exploring Ficus religiosa inflorescence powder as an eco-friendly and sustainable solution for the removal of crystal violet with a disposal solution.

This study investigates the potential of using Ficus religiosa inflorescence (peepal tree) as an efficient solution for removing crystal violet from simulated and industrial wastewater. Various analyses were conducted to understand the adsorbent's structure, including particle morphology, BET surface area, FTIR, and pHZPC. The adsorption process was studied under different physicochemical factors such as temperature, concentration, contact time, and pH. Results revealed rapid adsorption, with 94.15% removal efficiency within the first 15min at neutral pH. The highest observed adsorption capacity was 198.03mgg-1, following pseudo-second-order kinetics (R2 = 0.99), indicating chemisorption. The Langmuir model accurately described the adsorption pathway (R2 = 0.99), showing monolayer adsorption. Thermodynamic analysis indicated an exothermic, feasible, and spontaneous process with increased entropy. The adsorbent could be easily regenerated using a 1:1 MeOH/H2O mixture for up to three cycles, yielding up to 73.86%. Real-time application with industrial effluent containing crystal violet showed up to 44.70% adsorption. The experiments demonstrated reliability with evaluated standard deviations (0.017935-0.000577) and relative standard deviations (0.439-0.673%), confirming statistical reliability. In conclusion, it presents a sustainable and eco-friendly approach for removing crystal violet dye from diverse wastewater sources.

Enabling the Strengthened Structural and Interfacial Stability of High‐Nickel LiNi0.9Co0.05Mn0.05O2 Cathode by a Coating‐Doping‐Microstructure Regulation Three‐In‐One Strategy

AbstractHigh‐nickel layered cathodes exhibit great promise in advancing high‐energy‐density batteries owing to their significant advantages in high energy capacity and low cost, but they suffer severe structural and interfacial deterioration during cycling, resulting in safety risk and reduced cycle life. Herein, drawing inspiration from the low melting point infusion capability of Sb2Se3, a three‐pronged strategy aimed at simultaneously achieving coating on primary and secondary particles surface, Sb doping and elongated and slimed primary particle morphology is proposed and developed to fortify the structural and interfacial stability of high‐nickel LiNi0.9Co0.05Mn0.05O2 (NCM90) cathode. The “melted and infused” Sb2Se3 plays a beneficial role in the defensive effect on primary and secondary particle's surfaces, mitigating the interfacial deterioration. In addition, the enhanced structural stability is achieved by both Sb5+ doping and regulated primary particle morphology, contributing to the alleviated particle breakage and ultimately reinforced cycling stability. Consequently, the Sb2Se3‐NCM90 electrodes significantly improve cycling performance, which maintain higher capacity retentions of 96.6% at 4.3 V after 100 cycles and 80.2% at 1C/5C after 500 cycles. The proposed coating‐doping‐microstructure regulation three‐in‐one strategy for improving the cycling stability of high‐nickel NCM cathodes offers innovative ideas for the design and advancement of high‐energy‐density lithium‐ion batteries.

Solution-Based Suspension Synthesis of Li2S-P2S5 Glass-Ceramic Systems as Solid-State Electrolytes: A Brief Review of Current Research.

All-solid-state batteries are set to be the next generation of batteries offering improved performance and safety over current conventional lithium-ion batteries. Glass-ceramic Li2S-P2S5 solid-state sulfide electrolytes are promising contenders to achieve all-solid-state batteries with exceptional ionic conductivity on the order of 10-2 S cm-1. Solid-state processing techniques for synthesizing sulfide solid electrolytes are energetically and time consumptive. However, proposed solution processing techniques offer faster and lower temperature processes rendering them scalable. The chemistries that underly solution processing of sulfide solid electrolytes are still not well understood. This brief review highlights key aspects of current research into solution-based suspension synthesis processing techniques of Li2S-P2S5 sulfide solid electrolytes discussing precursor stoichiometries, solvent selectivity, reaction conditions, chemical impurities, and particle morphology with the intent of promoting further research into solution processing of sulfide solid-state electrolytes.

A Comparative Evaluation of Powder Characteristics of Recycled Material from Bronze Grinding Chips for Additive Manufacturing.

In the manufacturing process of ship propellers, large quantities of grinding chips are generated. These grinding chips result from the finishing of the blade surfaces after the primary casting process of the propeller. The aim of this study was to investigate and compare different preparation processes used to produce chip powders with sufficient powder quality for the additive manufacturing process of directed energy deposition. The preparation of the samples was performed through different sieving, milling and re-melting processes. For the characterization of the prepared samples, powder analysis according to relevant industry standards was carried out. It was found that the re-melting processes result in superior powder quality for additive manufacturing in terms of particle size, morphology, and flowability. For some characteristics, the powder exhibits even better properties than those of commercial powders. Furthermore, the powder properties of the milled samples demonstrate a promising potential for use in additive manufacturing.

Supercritical hydrothermal synthesis of ultra-fine Cu powders

ABSTRACT Ultra-fine Cu powders were synthesized using supercritical water as a reaction medium and formic acid as a reducing agent. The effects of reducing agent, reaction temperature, and complexing agent on the phase constituents, particle size distributions and morphology of the synthesized ultra-fine Cu powders were investigated. A complex mixture of Cu2O and Cu powders formed by pure supercritical water while high purity homogeneous ultra-fine Cu powders can be synthesized by supercritical water with formic acid as a reducing agent. Moreover, fine tuning of particle size and morphology can be realized by the addition of Ethylenediamine tetraacetic acid (EDTA). The modification mechanism of EDTA on the surfaces of ultra-fine Cu powders was investigated by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. EDTA adsorbed on the surfaces of nanoparticles by the dehydration reaction of carboxyl groups in the molecule of EDTA and hydroxyl groups on surfaces of copper nanoparticles (CuOH).

The application of freeze-thaw cycle treatment on landfill sludge: Impact on physicochemical properties and physical-mechanical characteristics

The physical-mechanical properties of dewatered sludge are important for the stability of landfills and their resource utilization. In this study, the physical-mechanical properties of sludge were comprehensively investigated by considering its various properties (e.g., particle morphology and size, compression and consolidation characteristics, shear strength, dewatering capacity, and microstructure) under different freeze-thaw cycles. The results indicated that extracellular polymers (EPS) will be destroyed during freeze-thaw cycles, and bound and interstitial water are converted to free water, which also enhances the sludge's dewatering efficiency and strength. Furthermore, multiple freeze-thaw cycles significantly enhanced the consolidation efficiency, leading to a denser sludge cake under pressure. A dense sludge structure enhances particle interlocking, improving internal friction angle and shear strength. The highest treatment efficiency was observed after 1–3 freeze-thaw cycles. Sludge properties tend to be stable when the freeze-thaw cycles are over 6. The research results will provide a reference for sludge dewatering reduction and its resource utilization.

Dynamic magnesiothermic reduction of various silica to porous silicon structures for lithium battery anodes

A dynamic magnesiothermic reduction (DMR) of various silica having different size and porosity is conducted to study the effects of silica properties on the ⅰ) DMR reaction kinetics, ⅱ) properties of resulting porous silicon (pSi) microparticles, and ⅲ) performances of pSi/C composites as anodes in lithium batteries. A DMR kinetic study using the Ginstling–Brounstein diffusion model shows that the smaller the silica particle size, the higher the reduction rate and the lower the apparent activation energy. Irrespective of silica properties, all the resulting pSi particles have mesoporous structures. The pSi particles comprise interconnected small primary silicon nanoparticles (approximately 30–40 nm in diameter) to render similar particle morphologies to those of the parent silica. Owing to these appealing features of pSi particles, pSi/C composites exhibit excellent cycling performance for over 200 cycles and high rate capabilities, whereas SiMP/C (prepared with a non-porous silicon microparticles) loses most of its capacity in early cycles owing to high resistance build-up during cycling. Overall, the DMR of silica precursors of several micrometers or less in size (preferably porous precursors) are desirable for the production of high-purity pSi microparticles for use in high-capacity and stable anodes for advanced lithium batteries.

Crack Initiation in Compacted Graphite Iron with Random Microstructure: Effect of Volume Fraction and Distribution of Particles.

Thanks to the distinctive morphology of graphite particles in its microstructure, compacted graphite iron (CGI) exhibits excellent thermal conductivity together with high strength and durability. CGI is extensively used in many applications, e.g., engine cylinder heads and brakes. The structural integrity of such metal-matrix materials is controlled by the generation and growth of microcracks. Although the effects of the volume fraction and morphology of graphite inclusions on the tensile response of CGI were investigated in recent years, their influence on crack initiation is still unknown. Experimental studies of crack initiation require a considerable amount of time and resources due to the highly complicated geometries of graphite inclusions scattered throughout the metallic matrix. Therefore, developing a 2D computational framework for CGI with a random microstructure capable of predicting the crack initiation and path is desirable. In this work, an integrated numerical model is developed for the analysis of the effects of volume fraction and nodularity on the mechanical properties of CGI as well as its damage and failure behaviours. Finite-element models of random microstructure are generated using an in-house Python script. The determination of spacings between a graphite inclusion and its four adjacent particles is performed with a plugin, written in Java and implemented in ImageJ. To analyse the orientation effect of inclusions, a statistical analysis is implemented for representative elements in this research. Further, Johnson-Cook damage criteria are used to predict crack initiation in the developed models. The numerical simulations are validated with conventional tensile-test data. The created models can support the understanding of the fracture behaviour of CGI under mechanical load, and the proposed approach can be utilised to design metal-matrix composites with optimised mechanical properties and performance.

Polyaniline microspheres using potassium polyvinyl sulfate as template for large-area broadband electrochromic device with large infrared emissivity variation

In the development of polyaniline (PANI) based large-area broadband electrochromic devices, we employed a controlled deposition process using potassium polyvinyl sulfate (PVSK) as a template to regulate the morphology of PANI. This resulted in consistent spherical particle morphology and heightened electrochemical activity in PVSK-PANI films. The simple structure of PVSK, coupled with its similar IR absorption to polyethylene and sulfuric acid, mitigated any detrimental effects on the broadband electrochromic properties. In small-area (2 × 2 cm²) PVSK-PANI electrochromic devices, we observed maximum emissivity changes of 0.47, 0.51, and 0.49 in the 3-5 μm, 8-14 μm, and 2.5-15 μm ranges, respectively. Expanding our approach to large-area devices (20 × 20 cm2), we achieved even more promising results. The PVSK-PANI based electrochromic devices achieved maximum emissivity changes of 0.55, 0.46, and 0.46 within the same spectral ranges of 3-5 μm, 8-14 μm, and 2.5-15 μm, respectively. Notably, these large-area electrochromic devices demonstrated a remarkable capacity to modulate infrared temperature by up to 10.4 °C at a background temperature of 70 °C.

Auranofin-loaded PLGA nanoparticles alleviate cognitive deficit induced by streptozotocin in rats model: modulation of oxidative stress, neuroinflammatory markers, and neurotransmitters.

Alzheimer's disease remains an unsolved neurological puzzle with no cure. Current therapies offer only symptomatic relief, hindered by limited uptake through the blood-brain barrier. Auranofin, an FDA-approved compound, exhibits potent antioxidative and anti-inflammatory properties targeting brain disorders. Yet, its oral bioavailability challenge prompts the exploration of nanoformulation-based solutions enhancing blood-brain barrier penetrability. The study aimed to investigate the neuroprotective potential of auranofin nanoparticles in streptozotocin-induced AD rats. Auranofin-containing polylactic-co-glycolic acid nanoparticles were formulated by the multiple emulsion solvent evaporation method. Characterization was done by determining entrapment efficiency, particle size distribution, surface charge, and morphology. An in vivo study was performed by administering streptozotocin (3mg/kg/i.c.v., days 1 and 3), auranofin (5 and 10mg/kg), auranofin nanoparticles (2.5 and 5mg/kg), and donepezil (2mg/kg) for 14days orally. Behavioral deficits were evaluated using the open field test, Morris water maze, objective recognition test, change in oxidative stress levels, and AD markers in the brain. Following the decapitation of the rats, the brains were excised to isolate the hippocampus. Subsequent analyses included the quantification of biochemical and neuroinflammatory markers, as well as the assessment of neurotransmitter levels. The characterization of auranofin nanoparticles showed an entrapment efficiency of 98%, an average particle size of 101.5 ± 10.3nm, a surface charge of 27.5 ± 5.10mV, and a polydispersity index of 0.438 ± 0.12. In vivo, administration of auranofin and auranofin nanoparticles significantly reversed streptozotocin-induced cognitive deficits, biochemical alteration, neuroinflammatory markers, and neurotransmitter levels. The present finding suggests that auranofin nanoparticles have more significant neuroprotective potential than auranofin alone. The therapeutic efficacy may be attributed to its antioxidant and anti-inflammatory properties, as well as its positive neuromodulatory effects. Therefore, our findings suggest that it could be a promising candidate for Alzheimer's disease therapy.

Particle morphology and soil properties affect the retention of copper oxide nanoparticles in agricultural soils.

The interaction between nanoscale copper oxides (nano-CuOs) and soil matrix significantly affects their fate and transport in soils. This study investigates the retention of nano-CuOs and Cu2+ ions in ten typical agricultural soils by employing the Freundlich adsorption model. Retention of nano-CuOs and Cu2+ in soils was well fitted by the Freundlich model. The retention parameters (KD, KF, and N) followed an order of CuO NTs > CuO NPs > Cu2+, highlighting significant impact of nano-CuOs morphology. The KF and N values of CuO NPs/Cu2+ were positively correlated with soil pH and electrical conductivity (EC), but exhibited a weaker correlation for CuO NTs. Soil pH and/or EC could be used to predict KF and N values of CuO NPs or CuO NTs, with additional clay content should be included for Cu2+.The different relationship between retention parameters and soil properties may suggest that CuO NTs retention mainly caused by agglomeration, whereas adsorption and agglomeration were of equal importance to CuO NPs. The amendment of Ca2+ at low and medium concentration promoted retention of nano-CuOs in alkaline soils, but reduced at high concentration. These findings provided critical insights into the fate of nano-CuOs in soil environments, with significant implications for environmental risk assessment and soil remediation strategies.

In-situ synthesis and characterization of lightweight steel matrix composites reinforced by TiB2

This study aimed to synthesize lightweight steels in situ reinforced with 5 % and 10 vol% of TiB2 and evaluate the microstructural, physical, and mechanical properties. The Fe-(15;20 wt%)Mn-3 wt%Al-0.1 wt%C with 5 and 10 vol% of TiB2 were produced by spray forming followed by hot rolling and annealing. The concept of varying the manganese content was to assess the influence of the matrix constitution on the composite properties. The findings pointed to a direct correlation between the manganese content and the size and morphology of the TiB2 particles. The presence of the ceramic particles re-established the modulus of elasticity above 200 GPa only for composites with a predominantly ferritic matrix. The composites with a matrix composed mostly of austenite showed no gains in ductility during the tensile tests despite the activation of the TWIP effect. However, their wear behavior stands out positively.

ZnSe:Cu@ZnS core/shell quantum dots synthesis by photochemical method for ethanol gas sensing

In the present study, ZnSe, ZnSe:Cu and ZnSe:Cu@ZnS core/shell quantum dots (QDs) were synthesized at room temperature using the new and fast microwave-assisted photochemical approach recently reported by the authors. Gas sensors based on these QDs were made and their sensitivity was studied in response to different flows of ethanol gas. Morphology and elemental analyses (conducted via FESEM, TEM, EDS and Map) were performed alongside XRD line profile analysis using Halder-Wagner approach. TEM results showed that the synthesized QDs exhibited spherical morphology of particles with an average size of approximately 20 nm, except for ZnSe:Cu(1.5 %)@ZnS (including nanorods). Ethanol gas sensing measurements were conducted under ambient conditions. Coating the Cu (1.5 mol%)-doped cores with ZnS increased the sensitivity, while the undoped samples exhibited the opposite trend. Among the fabricated sensors, the most sensitive one was made of ZnSe without microwave irradiation (MWIR), although it lacked desired stability. Meanwhile, ZnSe:Cu(1.5 %)@ZnS nanorods were identified as the most sensitive (optimal) sample, demonstrating favorable stability. Consequently, the gas sensitivity of the optimal sample to various ethanol gas flow rates was tested. It was observed that gas sensitivity increased with increasing flow rate up to 150 ml/min and decreased somewhat at higher flow rates.