Papers by Keyword: Aggregation

Abstract: This study aimed to evaluate filter efficiency for TiO₂ nanoparticle deposition across varied water chemistry and simulated conditions. The experimental results provided collision attachment efficiencies (α) of 0.001, 0.002, and 0.01 and filter coefficients (λ) of -0.003, -0.01, and -0.02. The authors used these collision attachment efficiencies to assess filter efficacy under simulated conditions, mainly removing naturally occurring nanoparticles spanning sizes from 1 to 100 nm. This experiment uncovered a strong correlation between TiO₂ nanoparticle deposition and water ionic strength, with aggregation becoming more pronounced as ionic strength increased. This phenomenon was especially prominent in instances lacking alum addition. Notably, the presence of alum resulted in the nanoparticles maintaining a dispersed state in the water, attaining enhanced stability by introducing excessive positive charges. Consequently, this study underscores how manipulating water's ionic strength can effectively induce nanoparticle destabilization during filtration. The implications of these findings are significant, as practical data about the behavior of diminutive like TiO₂ nanoparticles has been notably lacking.

Abstract: This study reviewed the synthesis of Titania with different shapes in the presence of cetyltrimethylammonium chloride (CTAC) as the famous stabilizer for directly altering the morphology and dimensions. These CTAC stabilizers usually provide the synthesis of Titania with a narrow size distribution and mostly single-crystalline structures in high yields. Many papers on the synthesis of Titania are available. However, only a few articles focus on the synthesis of Titania using CTAC as the stabilizer. The general rule for the shape transformation of Titania by CTAC stabilizer can be easily summarized based on the literature during the last ten year from https://www.sciencedirect.com/ as the data source.

Abstract: Gold nanoparticles (AuNPs) have received considerable attention recently because of their chemical properties and potential applications in the medical field.Monodispersed AuNPs in this paper are successfully synthesized by using some stabilized ligands including 3,5-dinitrobenzoic acid (DNBA) and sodium acetate (SA) dispersible in aqueous media, where NaBH₄ was used as a reducing agent to reduce KAuCl₄ from Au (III) to Au (0).The synthesized AuNPs are characterized by using UV–Vis spectroscopy to evaluate their surface plasmon resonance (SPR) absorption in a wavelength range of 500–650 nm. The size and morphology of AuNPs were determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS), where the results displayed that AuNPs with a strong SPR peak around 530 nm and 536 nm with an average size of 10 ± 1.2 nm and 14.0 ± 0.9 nm at the initial time for both DNBA-AuNP and SA-AuNP respectively. The synthesized AuNPs illustrate perfect chemical stability for more than 24 weeks in an aqueous solution. Therefore, the size of DNBA-AuNP was smaller and most stable than SA-AuNP, which may be due to 2 nitro groups that have resonance with the benzene ring leading to an increase in the stability of AuNPs.The stability of AuNPs in this work was monitored at a range of pH 2-12. Where high stability was showed at pH 6.6 ± 0.5, while the aggregation appears at more than pH 10 and less than pH.3.5.Herein, in this paper AuNPs have shown remarkable results against multi-drug resistance Pseudomonas aeruginosa. AuNP functionalized by SA ligand is shown to have a greater biological effect and be more effective than DNBA-AuNP. Due to the high stability of AuNP prepared in this work, it can be further tested to be an improved choice for more biomedical applications in the future.

Abstract: The effect of interfacial adhesion reduction at intensification of the nanofiller initial particles aggregation was found. It can be described with a simple empirical equation. The indicated equation precision is enough for prediction of the particulate-filled polymer nanocomposites reinforcement degree. The physical grounds of this effect can be described within the framework of fractal analysis.

Abstract: The fibrillation mechanism of insulin in acid solution has been studied by small angle X-ray scattering (SAXS). It was observed that insulin monomer unfolded in both conditions. Furthermore, in zinc free solution, insulin tend to aggregate on heating start in the first 5 min. The fibrillation through aggregation process continues until 30 min on heating. The similar phenomenon occurs in the presence of zinc ions. The SAXS data suggest that the presence of zinc ions prevent the long cylindrical fibril at the beginning of heating. However, after 20 min heating, the large cylindrical fibril of insulin formed in both conditions.

Abstract: The simple percolation model, in which critical indices are defined by the form of a reinforcing component of nanostructured composite structure, was proposed for the description of reinforcement degree for nanostructured composites polymer/2D-nanofiller. The indicated critical indices are close by absolute values to standard percolation indices. The form of reinforcing component controls the type of nanostructured composite. It has been shown that reinforcement degree of these nanomaterials is independent on modulus of elasticity of nanofiller, but is defined by its structure (aggregation level), created in polymer matrix. The percolation indices of a percolation model, which are due to the form of reinforcing component and nanocomposite type, are defined by its main characteristic – the fraction of phases division surface in overall sample volume and are the basic factor, controlling reinforcement degree of nanostructured composites.

Abstract: This study aimed to investigate the in-vivo effect of a static magnetic field (SMF) on blood falling time and velocity in a capillary tube. We generated a magnetic field using Helmholtz coils. We exposed rats with 2.4±0.2mT for a duration of one-four weeks and 1-8hrs/day. Blood samples were withdrawn and passed through a capillary viscometer under gravity. Results showed a significant reduction of blood falling time and an increase of blood falling velocity at 2 weeks exposure. The 4hrs and 8hrs exposure per day have reduced the blood falling time from 129±3.94sec to 53.2±1.80sec and 55±2.92sec respectively. The 2hrs exposure for 1 week reduced blood falling velocity from 0.19±0.004cm/sec-0.12±0.002cm/sec. The 4hrs exposure/day showed a similar trend to control samples for the entire durations except for the 4 weeks exposure, which took a long time to pass through the capillary.

Abstract: Carbon nanotubes aggregation process in aggregates (bundles) has been studied. This process results in essential reduction of nanocomposites attainable elasticity modulus. The bundles packing density is defined by aggregation expectation time and corresponding carbon nanotube walk dimension up to sticking with a similar nanotube.

Abstract: The applicability of irreversible aggregation model for theoretical description of nanofiller particles aggregation processes in polymer nanocomposites has been shown. The correspondence of the indicated model and strength dispersive theory results was obtained. The main factors, influencing on nanoparticles aggregation process, were revealed.

Abstract: Microporous aluminum fumarate (A520) is one of the very few metal-organic frameworks (MOFs) that have been promoted to the level of commercial applications and has recently been proven to exhibit a rigid character with an accessible permanent porosity. This study explored the maximum loading amount of A520 for mixed matrix membrane (MMM) preparation by blending it with polyimide (PI) using N-methylpyrrolidone (NMP) as solvent, without compromising the membrane integrity. Scanning electron microscope (SEM) images revealed that MOFs were able to infiltrate the pores and structures of the polymer, improving the interface and mechanical properties of the polymer, as supported by different characterizations like dynamic mechanical analysis (DMA), x-ray diffraction (XRD), and positron annihilation lifetime spectroscopy (PALS). Results showed that MOF loading beyond 10wt% revealed aggregations that compromised the integrity of the membrane.