Concentration Of Nanoparticles Research Articles

A multi-technique analytical approach to support (eco)toxicological investigation of zinc oxide nanoparticles

Understanding the mechanism of toxicity of nanoparticles and their behavior in biological environments is crucial for designing materials with reduced side effects and improved performance. Among the factors influencing nanoparticle behavior in biological environments, the release and bioavailability of potentially toxic metal ions can alter equilibria and cause adverse effects. In this study, we applied two on-line Field-Flow Fractionation (FFF) strategies and compared the results with off-line benchmarking centrifugal ultrafiltration to assess a key descriptor, namely the solubility of zinc oxide (ZnO) nanoparticles. We found that, at the highest nanoparticle concentrations, the nanoparticle-ion ratio quickly reaches equilibrium, and the stability is not significantly affected by the separation technique. However, at lower concentrations, dynamic, non-equilibrium behavior occurs, and the results depend on the method used to separate the solid from the ionic fraction, where FFF yielded a more representative dissolution pattern. To support the (eco)toxicological profiling of the investigated nanoparticles, we generated experimental data on colloidal stability over typical (eco)toxicological assay durations. The Zeta Potential vs pH curves revealed two distinct scenarios typical of surfaces that have undergone significant modification, most likely due to pH-dependent dissolution and re-precipitation of surface groups. Finally, to enhance hazard assessment screening, we investigated ion-dependent toxicity and the effects of exposure to fresh water. Using an in vitro human skin model, we evaluated the cytotoxicity of fresh and aged ZnO nanoparticles (exposed for 72 h in M7), revealing time-dependent, dose-dependent, and nanoparticle-dependent cytotoxicity, with lower toxicity observed in the case of aged samples.

Optical trapping-induced crystallization promoted by gold and silicon nanoparticles.

This study investigates the promotion of sodium chlorate (NaClO3) crystallization through optical trapping, enhanced by the addition of gold nanoparticles (AuNPs) and silicon nanoparticles (SiNPs). Using a focused laser beam at the air-solution interface of a saturated NaClO3 solution with AuNPs or SiNPs, the aggregates of these particles were formed at the laser focus, the nucleation and growth of metastable NaClO3 (m-NaClO3) crystals were induced. Continued laser irradiation caused these m-NaClO3 crystals to undergo repeated cycles of growth and dissolution, eventually transitioning to a stable crystal form. Our comparative analysis showed that AuNPs, due to their significant heating due to higher photon absorption efficiency, caused more pronounced size fluctuations in m-NaClO3 crystals compared to the stable behavior observed with SiNPs. Interestingly, the maximum diameter of the m-NaClO3 crystals that appeared during the size fluctuation step was consistent, regardless of nanoparticle type, concentration, or size. The crystallization process was also promoted by using polystyrene nanoparticles, which have minimal heating and electric field enhancement, suggesting that the reduction in activation energy for nucleation at the particle surface is a key factor. These findings provide critical insights into the mechanisms of laser-induced crystallization, emphasizing the roles of plasmonic heating, particle surfaces, and optical forces.

Calcium alginate films loaded with copper-molybdenum oxide nanoparticles for antimicrobial applications

The rise in petroleum-based plastic waste, driven by increased consumption from delivery services and e-commerce, necessitates the search for sustainable alternatives like alginate-based materials to mitigate environmental risks. However, alginate, a biopolymer, has limited physico-chemical properties, lacks antibacterial capacity, and exhibits low antiviral activity. To address these issues, this study synthesized Cu3Mo2O9 semiconductor nanoparticles (CMO) and integrated them into alginate films crosslinked with Ca2+, producing advanced nanocomposite films with varying nanoparticle concentrations (0–10 wt%). CMO nanoparticles release Cu2+ and Mo6+ ions and generate reactive oxygen species (ROS), even in the dark. Results show that CMO weakly interacts with alginate blocks, causing slight structural changes but not significantly altering mechanical or thermal properties. CMO released Cu2+ (150–250 ppb at 24 h) and Mo6+ ions (5–8 ppm at 24 h), with Cu2+ undergoing cation exchange with Ca2+ crosslinking ions. Antibacterial tests demonstrated the composites' effectiveness against Gram-negative Pseudomonas aeruginosa (97.30 % and 91.36 % growth inhibition at 5 % and 10 % CMO), Gram-positive methicillin-resistant Staphylococcus aureus (87.26 % and 96.82 % inhibition at 5 % and 10 % CMO), and Mycobacterium smegmatis (99.83 % and 99.97 % inhibition at 5 % and 10 % CMO). These composites also showed antiviral activity against bacteriophage phi 6 (99.81 % and 92.66 % inactivation at 5 % and 10 % CMO) and bacteriophage MS2 (92.32 % and 92.93 % inactivation at 5 % and 10 % CMO). The primary mechanism is attributed to the release of Cu2+ cations and ROS generation. These nanocomposite films exhibit broad-spectrum antimicrobial activity, offering potential industrial applications in packaging and antimicrobial surfaces.

Tiny silver bullets: silver nanoparticles are insecticidal to Culicoides sonorensis (Diptera: Ceratopogonidae) biting midge larvae.

Insecticide formulations with safer environmental profiles and limited off-target effects are desirable to manage medical and veterinary pests. Silver nanoparticles are insecticidal against mosquitos, nonbiting midges, and other insects. The biting midge, Culicoides sonorensis Wirth and Jones, is a vector of agriculturally important pathogens in much of the United States, and this study aimed to examine the insecticidal properties of silver nanoparticles in larvae of this species. Mortality of third-instar larvae was assessed daily for 7 days after exposure to concentrations of silver nanoparticles, sorghum polymer particles, and hybrid silver-sorghum polymer particles. Both silver nanoparticles and silver-sorghum polymer particles were insecticidal, but sorghum polymer particles alone did not significantly contribute to larval mortality. Concentrations of 100mg/liter of silver nanoparticles achieved >50% mortality at day 7, and 200mg/liter treatments achieved >75% larval mortality within 24h. The antimicrobial properties of silver nanoparticles were also examined, and culturable bacteria were recovered from larval-rearing media at 200mg/liter but not at 400mg/liter of silver nanoparticles. These data suggest that C. sonorensis larval mortality is primarily caused by silver nanoparticle toxicity and not by the reduction of bacteria (i.e., a larval food source). This work describes the first use of silver nanoparticles in C. sonorensis and shows the potential insecticide applications of these nanoparticles against this agricultural pest. The grain-polymer particles also successfully carried insecticidal silver nanoparticles, and their utility in loading diverse compounds could be a novel toxin delivery system for biting midges and similar pests.

Fabrication of PMMA nanocomposite biomaterials reinforced by cellulose nanocrystals extracted from rice husk for dental applications

The primary objective of global studies is to develop the properties and durability of polymers for various applications. When it comes to dental disability, denture base materials must have sufficient mechanical and tribological performance in order to withstand the forces experienced in the mouth. This work aims to investigate the effects of the addition of low content of cellulose nanocrystals (CNC) on the mechanical and tribological performance of the polymethyl methacrylate (PMMA) nanocomposites. Different weight percent of CNC (0, 0.2, 0.4, 0.6, and 0.8 wt%) were added to the PMMA matrix followed by ball milling to evenly distribute the nanoparticles reinforced phase in the matrix phase. The findings emphasize the significant impact of CNC integration on the performance of PMMA nanocomposites. By increasing the content of the CNC nanoparticles, the mechanical properties of PMMA were improved. In addition, the tribological outcomes demonstrated a significant reduction in the friction coefficient besides an enhancement in the wear resistance as the weight percentage of nanoparticles increased. The surface of the worn samples was investigated by utilizing SEM to identify the wear mechanisms corresponding to the different compositions. In addition, a finite elment model (FEM) was developed to ascertain the thickness of the worn layer and the generated stressed on the surfaces of the nanocomposite throughout the friction process.

Enhancing Polylactic Acid Properties with Graphene Nanoplatelets and Carbon Black Nanoparticles: A Study of the Electrical and Mechanical Characterization of 3D-Printed and Injection-Molded Samples.

This study investigates the enhancement of polylactic acid (PLA) properties through the incorporation of graphene nanoplatelets (GNPs) and carbon black (CB) for applications in 3D printing and injection molding. The research reveals that GNPs and CB improve the electrical conductivity of PLA, although conductivity remains within the insulating range, even with up to 10% wt of nanoadditives. Mechanical characterization shows that nanoparticle addition decreases tensile strength due to stress concentration effects, while dispersants like polyethylene glycol enhance ductility and flexibility. This study compares the properties of materials processed by injection molding and 3D printing, noting that injection molding yields isotropic properties, resulting in better mechanical properties. Thermal analysis indicates that GNPs and CB influence the crystallization behavior of PLA with small changes in the melting behavior. Dynamic Mechanical Thermal Analysis (DMTA) results show how the glass transition temperature and crystallization behavior fluctuate. Overall, the incorporation of nanoadditives into PLA holds potential for enhanced performance in specific applications, though achieving optimal conductivity, mechanical strength, and thermal properties requires careful optimization of nanoparticle type, concentration, and dispersion methods.

Development of a cellulose nanofiber composite film containing CuO/ZnO nanoparticles and its human norovirus inactivation properties in clams

Human norovirus (HuNoV) threatens human health worldwide, highlighting the critical need for antiviral materials. In this study, copper and zinc nanoparticles (NPs) as inorganic antiviral materials and a cellulose nanofiber (CNF) were selected to construct a hybrid inorganic-organic composite film (CuO/ZnO NPs-CNF) against MS2 and murine norovirus 1 (MNV-1) (surrogates for HuNoV) viruses. Selected NPs concentrations (50 µM of CuO NPs and 5 mM of ZnO NPs) showed non-toxicity (89.88 % of cell viability) through the MTT assay. Upon the development and characterization of the CuO/ZnO NPs-CNF film, high compatibility between CuO/ZnO NPs and CNF was identified, along with consistent thickness, low moisture content, and water solubility. A synergistic antiviral effect was exhibited in vitro and on the film against MS2 and MNV-1 in the mentioned co-treated inorganic matrix within 1 h. The antiviral stability of the film was also maintained at various temperatures (−18 °C, 5 °C, and 25 °C) and humidities (20–30 %, 50–60 %, and 70–80 %). When a synergistic antiviral effect was exhibited on the CuO/ZnO NPs-CNF film against both MS2 and MNV-1, mechanisms analysis by SDS-PAGE and RT-qPCR revealed that there were damages to both capsid protein and RdRP. The application of CuO/ZnO NPs-CNF film on clams resulted in a significant decrease in the survival rate of MS2 by up to 65.67 % and MNV-1 by up to 78.62 % when treated at low temperatures compared to the CNF film. Taken together, these results suggest that the CuO/ZnO NPs-CNF film could be used as potential anti-HuNoV agent in the food industry.

Analysis of impulse withstand voltage of ester-based nanofluids

Ester-based nanofluids constitute an effective ecological alternative to petroleum-derived dielectric fluids for electrical engineering industry. Pulse induced dielectric breakdown is a key cause of power device failure. In this paper, we deal with the lightning impulse breakdown voltage (LI BDV) in natural and synthetic ester-based (NE and SE) nanofluids with various concentrations of magnetite (Fe3O4) and fullerene (C60) nanoparticles. The nanofluids show a decrement in positive polarity LI+ BDV as compared with the base ester. Negative polarity LI- BDV in the nanofluids is similar to that of base oils. Weibull statistical distributions are applied to analyse the results at different cumulative probabilities of 1 %, 10 %, and 50 %. Natural ester with C60 nanoparticles shows higher positive LI+ BDV values at a low probability level, while the negative LI- BDV reaches higher values at higher probability levels. The decreased LI BDV in NE and SE due to the magnetite nanoparticles are attributed to the nanoparticle clustering and percolation. The tendency of C60 nanoparticles to enhance the LI BDV in NE but not in SE is interpreted in the view of the nanoparticle concentration and oil's viscosity effect on the streamer branching and propagation.

Repurposing Cotton Gin Trash for Cellulose Nanofibril-Silver Hybrid and Ultralight Silver-Infused Aerogel.

Cellulose nanofibril-silver (CNF-Ag) hybrid and ultralight silver-infused aerogel were produced using cotton gin trash (CGT), an abundant agro-waste material. This repurposing of CGT was achieved by exploiting its potential for CNF extraction and the in situ synthesis of silver nanoparticles (Ag NPs). CNFs were extracted from CGT through a mechanical shearing process. These CNFs served as a multifunctional nanotemplate for the controlled reduction of Ag ions, efficient nucleation, and stabilization of NPs, resulting in the production of a high concentration of Ag NPs (ca. 19 wt %) within the CNFs. Transmission electron microscopy images of cross-sectioned CNFs confirmed the uniform dispersion of NPs (ca. 18 nm diameter) inside the CNFs. Rietveld refinement analysis of X-ray diffraction patterns revealed that CNFs produced smaller Ag crystallites compared to CGT microparticles. The CNF-Ag hybrid was then fabricated into an aerogel using freeze-drying, with its weight being light enough to rest on a cotton flower's stamen. The infusion of Ag NPs led to approximately 20% reductions in the specific surface area and pore volume of the aerogel.

Thermal energy storage, heat transfer, and thermodynamic behaviors of nano phase change material in a concentric double tube unit with triple tree fins

The contribution of this study is the proposal of a synergistic composite enhancement strategy involving tree fins and nanomaterials to improve the low thermal performance of phase change material (lauric acid) in a typical double tube latent heat thermal energy storage unit. The effects of nanoparticle concentrations and tree fin branching angles on the fluid dynamics, melting time, heat transfer, energy storage, and entropy generation characteristics were investigated. By employing tree fins, the melting time was respectively reduced by up to 60.20% and 36.05% compared to the finless case and the rectangular fins, while the energy storage power was respectively boosted by up to 143.36% and 37.45%. The increase of nanoparticle concentration was beneficial for melting heat transfer, and the dendritic fins with a bottom angle of 90° and a top angle of 30° yielded the highest energy storage performance. The total entropy generation of the melting process was mainly governed by the thermal entropy generation, and it showed a decreasing trend with the increase of time. In contrast to the finless configuration, the incorporation of fins diminished the integrated entropy generation value. Similarly, an elevation in nanoparticle concentration also led to a reduction of the integrated entropy generation value.

Green Synthesis of Iron Nanoparticles Using Spinacia oleracea and Their Role in Antioxidant Defence

The green synthesis of iron oxide nanoparticles (Fe2O3) using Spinacia oleracea leaf extract is explored in this study. Iron oxide nanoparticles are noted for their unique properties, such as enhanced chemical reactivity due to their high specific surface area to volume ratios. Unlike traditional physical and chemical methods, green synthesis presents an environmental friendly alternative, leveraging biological processes for nanoparticle production. This method is particularly significant due to its potential applications in various fields, including medicine, where iron nanoparticles demonstrate antibacterial activity. However, limited research exists on their antioxidant properties. In this research, Spinacia oleracea leaf extract is utilized to synthesize iron oxide nanoparticles, followed by characterization using UV-Visible spectroscopy, FTIR, XRD, and SEM techniques. The results underscore the necessity for further investigation into the impact of nanoparticles on biological processes and the long-term effects of high nanoparticle concentrations on ecological stability. Additionally, this study includes an evaluation of antioxidant properties of the nanoparticles to address gaps in current research. Key Words Green synthesis, iron oxide, ecological stability, antioxidant, biological, nanoparticles.

Fabrication of omniphobic PVDF membrane with SiO2–FeOOH hierarchical structures for robust membrane distillation

Omniphobic membrane has been demonstrated as an effective strategy to mitigate membrane wetting and fouling risks in membrane distillation (MD) processes. In this work, novel omniphobic membranes with hierarchical re-entrant surface structure were fabricated. Firstly, the FeOOH nanorods were deposited on the polydopamine (PDA) pre-treated poly (vinylidene fluoride) PVDF membrane. After that, the SiO2 nanoparticles (NPs) were coated on the FeOOH nanorods via electrostatic attraction to form hierarchical structures. Finally, the fluorosilane was utilized to reduce the membrane surface free energy, contributing to PVDF based omniphobic membranes. The effects of reaction time, FeCl3·6H2O and SiO2 NPs concentrations on membrane properties, including membrane surface morphology, average pore size, contact angles (CAs), surface roughness and permeate flux, were investigated in detail. The resulting omniphobic membranes showed high CAs towards various tested liquids, such as 0.4 mM sodium dodecyl sulfate (SDS) solution (143.9 ± 0.8°), hexadecane (113.5 ± 3.2°) and mineral oil (132.5 ± 2.8°). This membrane exhibited outstanding performance in a continuous 50-h vacuum membrane distillation (VMD) process with a 10 wt% NaCl feed solution. Besides, the anti-oil-fouling properties were further assessed with a feed solution containing 200-ppm hexadecane and 3.5-wt% NaCl, the omniphobic membrane exhibited steady permeate flux of above 24.18 kg m−2 h−1 and a 99.99 % rejection rate during 50-h testing. Finally, the omniphobic membrane showed high anti-wetting properties by SDS/salt solution. This work introduces a new strategy for fabricating omniphobic membranes that shows significant potential for treating complex industrial wastewaters.

Transformer for low concentration image denoising in magnetic particle imaging.

Objective.Magnetic particle imaging (MPI) is an emerging tracer-basedin vivoimaging technology. The use of MPI at low superparamagnetic iron oxide nanoparticle concentrations has the potential to be a promising area of clinical application due to the inherent safety for humans. However, low tracer concentrations reduce the signal-to-noise ratio of the magnetization signal, leading to severe noise artifacts in the reconstructed MPI images. Hardware improvements have high complexity, while traditional methods lack robustness to different noise levels, making it difficult to improve the quality of low concentration MPI images.Approach.Here, we propose a novel deep learning method for MPI image denoising and quality enhancing based on a sparse lightweight transformer model. The proposed residual-local transformer structure reduces model complexity to avoid overfitting, in which an information retention block facilitates feature extraction capabilities for the image details. Besides, we design a noisy concentration dataset to train our model. Then, we evaluate our method with both simulated and real MPI image data.Main results.Simulation experiment results show that our method can achieve the best performance compared with the existing deep learning methods for MPI image denoising. More importantly, our method is effectively performed on the real MPI image of samples with an Fe concentration down to 67μgFeml-1.Significance.Our method provides great potential for obtaining high quality MPI images at low concentrations.

A critical review on synthesis and application aspect of venturing the thermophysical properties of hybrid nanofluid for enhanced heat transfer processes

Recently, nanofluids (NFs) have gathered significant attention among researchers due to their varied properties, which can be made per the requirements. NFs, created by infusing nanoparticles into a base-fluid, enhance their fundamental properties. A hybrid nanofluid (HNF) is a nanofluid (NF) containing different types of nanoparticles, and it is being studied for its customizable properties. Recently, researchers delved into the applications regarding HNFs, particularly in cases relating to heat transfer (HT). This study analyzes HNFs’ preparation methods and thermophysical properties, giving more importance to their applications in HT, including heat-exchange, solar thermal, and cooling systems. Considering stability, the two-step synthesis method is preferred over the single-step method. Multiple research efforts have led to the development of a fluid that possesses superior HT capabilities compared to the base-fluid. However, while bettering HT, an increase in volume concentration (VC) also raised challenges such as increased viscosity and pressure drop, particularly in porous media, necessitating additional pumping power. The use of turbulators and other configurations, along with HNF in systems like parabolic trough solar collectors (PTSCs), enhances solar thermal systems (STSs) by improving their HT capabilities. An advantageous use of EG-based multiwalled carbon nanotubes (MWCNTs) NF in solar collectors (SCs) is their ability to increase thermal efficiency and decrease carbon dioxide emissions, making them an attractive choice for use in SCs. Researchers face significant challenges in determining the ideal composition and concentration of nanoparticles in HNFs to attain optimal HT without causing excessive viscosity that could impede practical usability. Specifically, this study examines the distinctive thermophysical characteristics of HNFs that substantially improve their efficacy in HT applications.

Optimizing nano-TiO2 and ZnO integration in silica-based high-performance concrete: Mechanical, durability, and photocatalysis insights for sustainable self-cleaning systems

This research presents novel findings by exploring the synergistic effects of incorporating nano-sized titanium dioxide (TiO₂) and zinc oxide (ZnO) nanoparticles into a high-performance concrete (HPC) matrix. The study utilized Response Surface Methodology (RSM) to determine the optimal combinations of TiO₂ and ZnO for achieving peak performance within the matrix. Various combinations of TiO₂ and ZnO, ranging from 0 % to 2 %, were incorporated into HPC mixes, focusing on evaluating their effects on compressive strength (CS), splitting tensile strength (STS), flexural strength (FS), durability, and photocatalytic properties. The results revealed that maintaining higher proportions of TiO₂ over ZnO led to superior mechanical properties, with the most effective combination determined to be 2 % TiO₂ and 1.33 % ZnO, which agrees with the prediction by the RSM model and verified through experimental testing. However, these combinations did not significantly enhance the durability properties of the HPC samples when exposed to acidic curing for three months.On the other hand, the photocatalytic properties of HPCs with different combinations of TiO₂ and ZnO were significantly improved. The combination with the maximum content of both nanoparticles had only 23.7 % of Rhodamine B remaining on its surface after 100 hours of UV radiation. Comparing the individual effects of TiO₂ with ZnO, it was observed that a higher TiO₂ dosage (2 %) caused earlier Rhodamine B discolouration compared to a higher ZnO dosage (2 %). Therefore, based on the photocatalytic degradation efficiency, it was concluded that the concrete can confer self-cleaning properties under UV radiation and serve as a precursor for developing self-cleaning concrete composites for more sustainable and resilient structures.

Application of Box-Behnken design with RSM to predict the heat transfer performance of thermo-magnetic convection of hybrid nanofluid inside a novel oval-shaped annulus enclosure

The study of flow around a stationary or rotating circular cylinder holds substantial importance in numerous engineering disciplines, including building, bridge, and structural engineering. This knowledge is utilized to manage flow-induced vibrations, implement blowing or suction techniques, control moving surfaces, and develop acoustic thrusters and synthetic jets. The current aims to analyze the numerical and RSM optimization with Box–Behnken design (BBD) for the buoyancy driven convective flow and heat management features of Magneto Fe3O4−MWCNTs/water hybrid nanofluid filled inside a novel oval-shaped annulus enclosure with concentric hot circular cylinder. The water used as base fluid and iron oxide and Multiwall carbon nanotubes as nanoparticles. The finite element method is employed to solve numerically the coupled equations. The RSM optimization with Box–Behnken design (BBD) is applied to optimize the heat transfer rate across different three factors. The stream lines, isotherms and line graphs are design for different flow parameters effect. The results indicated that heat transfer is enhanced by using of hybrid nanofluid. The velocity is reduced via increment in Hartmann number. The local Nusselt number is increases with increment in the values of the Rayleigh number. Furthermore the Heat transfer rate is boosted up with increases the concentration of nanoparticles.

Evaluation of cold plasma treatment technology in biosynthesized silver nanoparticles encapsulated with chitosan by Aliinostoc persicum SA14 against HepG-2

Hepatocellular carcinoma (HCC) is the commonest cancer and the third most common cause of cancer-related mortality. The combination of cold atmospheric plasma (CAP) and nanoparticles is a promising treatment for hepatocellular carcinoma cancers. In the present study, activated water was prepared using the cold atmospheric plasma technique (JET and PAW), and then the biosynthesis ability of silver nanoparticles by the cyanobacterium Aliinostoc persicum SA14 was measured after cultivation in the culture medium containing activated water at 5, 15, and 20 min. After the encapsulation of nanoparticles with chitosan and UV–visible spectroscopy analysis, the characterization of AgNPs, including FTIR analysis. X-ray diffraction, particle size and zeta potential, SEM, TEM, as well as cytotoxicity assays against HepG-2 cell lines, were performed. The comparison of the absorption spectra of silver oxide nanoparticles prepared by the boiling-dender method at concentrations and different times showed that the production of silver nanoparticles was confirmed for all three samples based on the amount of absorption obtained. The outcomes of field emission scanning electron microscopy at all magnifications exhibited that spherical nanoparticles are scattered on the surface of the polymer matrix. Furthermore, the FT-IR spectrum and XRD crystallography confirmed the success of chitosan's production of microcoated silver nanoparticles. The results of the cytotoxicity test against HepG-2 cell lines showed that with increasing concentrations of silver nanoparticles, the survival frequency of cancer cells declined significantly. In conclusion, the tests confirmed that the silver nanoparticles produced by cyanobacteria act as both a stabilizing and reducing agent. The results indicated that CAP decreases nanoparticle size, decreases surface charge distribution of AgNP, and induces uptake, aggregation, and enhanced cytotoxicity against HepG-2 in vitro. The chitosan-AgNPs with cold plasma could have potential applications in the food, agricultural, and pharmaceutical industries.

Do nanoparticles and colloids replenish soil phosphorus in the rhizosphere of winter wheat?

The rhizosphere is generally depleted in nutrients, but as a hotspot of microbial activity it fosters crop P uptake. We hypothesized that P contents of water extractable nanoparticles (<0.1 μm) and small sized colloids (<0.45 μm) differ between non-rhizosphere and rhizosphere soil. To test this hypothesis, rhizosphere and non-rhizosphere soils (Luvisol and Cambisol) were sampled at harvest period of winter wheat near Selhausen (Germany). Microaggregate and colloidal fractions in the size range of 53–250 μm, 20–53 μm, 0.45–20 μm, and <0.45 μm were separated by wet-sieving and centrifugation. Subsequently, the colloids <0.45 μm were further isolated in 0.66–20 nm, 20–100 nm and 100–450 nm fractions using asymmetric flow field flow fractionation (AF4) and directly analyzed by online coupled organic carbon detector (OCD) and inductively coupled plasma mass spectrometry (ICP-MS) for element composition. No significant differences (p > 0.05) were measured between rhizosphere and non-rhizosphere soil P contents of microaggregate fractions. The rhizosphere soil, however, showed ∼26 % depletion of average P content in the 0.66–20 nm fraction, which went along with an enrichment of P content of the 100–450 nm fraction by a factor of two. Apparently, P uptake by plants results in a redistribution of P in the rhizosphere, with small nanoparticles providing available P to plants while excess residual P is bound to fine colloids.

Thermal magnetization transport analysis featuring darcian and multi-physical rheological characteristics in chemically reactive dual convective tangent-hyperbolic nanomaterial confined by vertical cone

The Soret-Dufour characteristics elaborate the phenomena of cross-diffusion where solutal gradients yield heat flux (Dufour aspect) and thermal gradients engender mass flux (Soret effect). Such consideration finds significance in multi-component fluid systems, influencing both heat-mass transportation processes. This study evaluates the porous medium characteristics in convectively heated tangent-hyperbolic nanomaterial driven by a magnetized convected cone. The analysis features Buongiorno nanomaterial model which accounts Brownian motion together with thermophoresis. Thermal transport expression which reports heat transfer characteristics is modeled by considering thermal radiation, convective thermal conditions and heat generation while mass transfer considers the chemical reaction effects. Dimensional expressions are converted into dimensionless forms deploying similarity transformations ensuing in a set of ODEs (ordinary differential expressions) which are computed by deploying bvp4c algorithm. Graphical and tabular behavior of velocity, nanoparticles concentration and temperature fields is inspected corresponding to related variables. This research highlights key findings, revealing a decrease in Nusselt number with increasing heat generation, Dufour parameter and thermophoresis parameter values while opposite trends are verified for radiation parameter values. The velocity function declines for escalating Weissenberg number, magnetic field and permeability parameters but it upsurges with material and buoyancy parameters.

Size resolved particle contribution to vehicle induced ultrafine particle number concentration in a metropolitan curbside region

The concentrations and behavior of nano particles (10–1000 nm) in Delhi, a densely populated megacity, in different seasons (winter, spring, summer, monsoon, and autumn) are examined, for the first time. The concentration of particles is classified into four different sizes as Nnuc (10–30 nm, nucleation), Nsatk (30–50 nm, small Aitken), Nlatk (50–100 nm, large Aitken), and Nacc (100–1000 nm, accumulation mode), and the total (10–1000 nm) particle number concentration (PNC) as Ntotal. PNC ranges between 104 cm−3 and 106 cm−3 over Delhi during the year, and the highest concentration occurs in winter. Winter concentration is 2, 1.6 and 1.3 times higher than monsoon, summer, autumn and spring concentrations, respectively. Nnuc, Nsatk, Nlatk and Nacc and their respective contributions to total PNC exhibit significant seasonal variations. During winter Nlatk and Nacc contribute more to total due to coagulation, with Nacc alone contributing >40% to total PNC. Nnuc, Nsatk, and Nlatk are higher in spring and summer during mid-day due to nucleation and/or ultrafine particle burst events. The direct primary emissions from engine exhaust produce a prominent double hump structure during morning and evening peak hours in winter and autumn. PNC and their contributions exhibit day-night variations as they are influenced by variations in emission sources and meteorological parameters (wind speed, relative humidity, temperature, solar radiation and boundary layer height) between day and night. Carbon monoxide correlates positively with Nacc in all seasons (R2 ≥ 0.5) as fossil fuel emission is a predominant source for gases and particles in the study environment. These quantitative results on seasonal variations of nano particles and air pollutants together with the knowledge on seasonal variations in meteorological parameters and atmospheric dynamics provide a foundation which can positively contribute better to the urban planning and devising mitigation measures aimed at improving air quality and public health.