Suspended Particle Size Research Articles

Sinking Versus Suspended Particle Size Distributions in the North Pacific Subtropical Gyre

AbstractThe particle size distribution (PSD) is a fundamental property that influences all aspects of phytoplankton ecology. In particular, the size (e.g., diameter d [μm]) and sinking speed w (m/day) of individual particles are inextricable, but much remains unknown about how d and w are related quantitatively for bulk particulate matter. There is significant interest in inferring sinking mass fluxes from PSDs, but doing so requires knowing how both mass and w scale with d. To this end, using both laser diffraction and imaging, we characterized for the first time both sinking and suspended PSDs in the oligotrophic North Pacific subtropical gyre. Comparing these PSDs via a power law parameterization indicates an approximately linear w‐to‐d scaling, suggesting particles are more fractal‐like than sphere‐like in this respect. This result is robust across multiple instruments, depths, and sediment trap deployments and is made comparatively precise by a high degree of replication.

A national‐scale study of spatial variability in the relationship between turbidity and suspended sediment concentration and sediment properties

AbstractTurbidity, an index of light side‐scattering, depends on the mass concentration of suspended sediment (SS) within water. Turbidity of river water is regulated by the presence of suspended particulate matter and is used to identify visual changes in response to SS. We used data from the New Zealand National River Water Quality Network, to calculate “specific turbidity” (K; turbidity normalised to mass concentration of suspended particulates). Specific turbidity is shown here to be an effective metric to assess the effect of suspended material composition and particle size distribution of suspended particulate matter over different landscape characteristics, and the effect on SS‐turbidity relationships. Of the catchment characteristics considered in our study, specific turbidity was most responsive to lithological factors, and relatively insensitive to land use and soil parameters. Decreasing particle size has a positive linear response to K, attributed to the higher proportion of ultra‐fine particulate material that is generated by certain lithologies, underscoring the lithological influence on K. SS‐turbidity relationships, therefore, vary spatially across New Zealand's national record of water clarity, and K is considered a useful index for inter‐catchment comparison of SS than turbidity alone.

Seasonal and tidal variability of the hydrology and suspended particulate matter in the Van Uc estuary, Red River, Vietnam

Abstract This study explores the seasonal and tidal changes in flow and suspended matter dynamics in the tropical and macrotidal Van Uc River estuary (North Vietnam) and aims at understanding, among others, the sediment delivery to the ocean and the processes behind the estuarine siltation. Four campaigns took place during the contrasting high flow and low flow seasons, for each during neap and spring tides. Water and suspended matter fluxes, salinity, turbidity and particle size distribution (PSD) were measured for 24 h at three cross sections along the estuary. During the high-flow season, the estuary was mixed, with seaward sediment flux during neap tide and ephemeral up-estuary sediment flux at spring tides due to tidal distortion. During the low-flow season, the system transitioned from partially mixed to highly stratified with salty waters intrusions, salt wedge presence and up-estuary sediment flux varying with the tidal regime. The highest up-estuary sediment flow occurred during low-flow at spring tides and represented ⅔ of the outflow. The lower river discharge, the higher PSD variation. The increasing proportion of microflocs with increasing salinity as compared to primary particles and flocculi was observed at both seasons. Higher tidal variations of PSD at spring tides indicate the strong effect of turbulent shear. These findings also provide a new benchmark for hydro-sedimentary model calibration/validation.

Effect of Particle Size and Viscosity of Suspensions on Topical Ocular Bioavailability of Budesonide, a Corticosteroid.

Purpose: To determine the effect of particle size and viscosity of suspensions on topical ocular bioavailability of budesonide, a corticosteroid drug. Methods: Budesonide microparticle and nanoparticle (MP and NP) suspensions were prepared with or without homogenization and microfluidization. Using different grades of hydroxyl propyl methyl cellulose, low viscosity NP (NP-LV) and low and high viscosity MP (MP-LV and MP-HV) were prepared. Suspensions were characterized for particle size, viscosity, and osmolality. Budesonide suspensions were administered topically to rabbits and aqueous humor was collected and analyzed for budesonide. Budesonide Cmax, tmax, and the area under the concentration time curve (AUC (0-6h)) values were determined. The geometric mean ratio of AUC and bioequivalence was evaluated using a bootstrap method. Results: The particle sizes for NP and MP were ∼700 and 2,000 nm. The viscosities for low and HV formulations were ∼5 and 50 cP. The geometric mean budesonide Cmax values for the suspensions NP-LV, MP-LV, and MP-HV were 0.22, 0.22, and 0.31 μg/g, tmax values were 0.67, 0.60 and 0.53 h, and AUC0-6h values were 0.72, 0.53, and 0.95 μg h/g, respectively. Bootstrap analysis indicated that the 90% confidence intervals of the geometric mean ratio of AUC0-6h values were 1.00-1.74 (MP-HV vs. NP-LV), 0.57-0.96 (MP-LV vs. NP-LV), and 0.45-0.70 (MP-LV vs. MP-HV). Conclusions: The 3 budesonide suspensions assessed in this study were not bioequivalent. Results suggested that an increase in viscosity improves the bioavailability of budesonide from the microsuspension formulation.

Relationship between particle size and lung retention time of intact solid lipid nanoparticle suspensions after pulmonary delivery

The relationship between the particle size and lung retention time of inhaled nanocarriers was unclear, and this uncertainty hampered the design of nanocarriers for pulmonary delivery. The debate resulted from a lack of knowledge regarding the integrity of the involved nanocarriers. A distinguishable bioimaging probe which could differentiate between integrated and disintegrated nanocarriers by emitting different signals was introduced to address this problem. The aza-BODIPY structured aggregation-caused quenching (ACQ) probes were promising candidates, because they showed intense fluorescence signals in intact nanocarriers while quenched after the decomposition of nanocarriers. This attribute was called an on-off switch. In this paper, ACQ probes were encapsulated into a solid lipid nanoparticle suspension (SLNS) with different particle sizes (120–480 nm), and the relationship between particle size and lung retention time after pulmonary delivery was investigated in BALB/c mice. The results showed that a larger particle size led to a longer lung retention time. By comparing with the results of a non-water-quenching probe, the SLNS systems were found to be mostly intact in the pulmonary region. These findings will serve as a firm basis for the design and development of nanocarriers for pulmonary delivery.

Smartphone‐Based Colorimetric Method to Quantify Iron Concentration and to Determine the Nanoparticle Size from Suspensions of Magnetic Nanoparticles

AbstractAdvanced uses of smartphones are changing lifestyles, and may have a great impact in materials science in the near future. In this work, the use of these devices to develop fast, simple, and cheap methods to characterize magnetic nanoparticle suspensions is tested. A series of dilutions of a wide library of magnetic nanoparticles, composed of iron oxide materials in the range between 3 and 43 nm, with two different shapes and four different coatings is prepared. The colloid color is analyzed using the RGB (red, green, blue) color model. Ratios of these parameters are correlated with the suspension iron concentration and with the nanoparticles average size. A linear relationship between the color (in particular the G/R ratio) and both the colloid iron content and the particles size is found. The link between these parameters allows the development of two new methods to determine either the concentration or the particle size of magnetic nanoparticle suspensions just by acquiring images from suspensions of iron oxide magnetic nanoparticles with a smartphone.

Rabies Vaccine Characterization by Nanoparticle Tracking Analysis

There are concerns that effectiveness and consistency of biopharmaceutical formulations, including vaccines, may be compromised by differences in size, concentration and shape of particles in suspension. Thus, a simple method that can help monitor and characterize these features is needed. Here, nanoparticle tracking analysis (NTA) was used to characterize particle concentration and size distribution of a highly-purified rabies vaccine (RABV), produced in Vero cells without raw materials of animal origin (RMAO). The NTA technique was qualified for characterization of RABV particles by assessing the stability profile of vaccine particles over 5–55 °C. Antigenicity of the viral particle was also monitored with the enzyme-linked immunosorbent assay (ELISA) and NTA. RABV particle size diameters were 100–250 nm (mean:150 nm), similar to sizes obtained when labelled with rabies anti-G D1–25 monoclonal antibody, suggesting mainly antigenic virus-like particles, also confirmed by transmission electron microscopy. Thermal stress at 55 °C decreased the concentration of anti-G D1–25-labelled particles from 144 hours, coherent with conformational changes leading to loss of G protein antigenicity without impacting aggregation. Results from RABV antigenicity assessment during the 24 months monitoring of stability showed good correlation between NTA and ELISA. NTA is a suitable approach for the characterization of biopharmaceutical suspensions.

Investigation of suspended particle size effects on clogging of soil filters under laminar flow

Soil filters that are commonly used to stabilize base soils in infrastructures are gradually prone to microparticle accumulation. Sequestration and accumulation of suspended solid particles in fluid on the media surfaces of the filter lead to porosity and permeability reduction through the porous medium and cause physical clogging. This reduces hydraulic conductivity and eventually filters drainage capacity. This study evaluated the reduction in hydraulic conductivity and porosity of a soil filter with sand bed (average diameter 3.55 mm) affected by suspended particles in the fluid of silica and with the average sizes of 4, 20 and 40 microns with a concentration 1 g/L. Results show input suspended particle size has been effective on the reduction rate of the hydraulic conductivity and larger microsilica particles reduce hydraulic conductivity and porosity particularly in early days of filtration more rapidly. For the 4, 20 and 40-micron microparticles, the pressure drop is stabilized after 14, 10 and 7 days, respectively. The average stabilized values are 540, 1460 and 1200 Pascal, respectively. Pressure drop increase during the operation of the soil filter shows that hydraulic conductivity and porosity in porous media is reduced under different circumstances of input microsilica particle size.

Effect of solvents and dispersants on polyol synthesis of V–ZrSiO4 nanopigment stable suspension for ink application

The polyol method was implemented to prepare stable V–ZrSiO4 suspensions as ceramic ink. It was shown how the rheology, surface tension, viscosity, and particle size of suspensions were affected by the length of polyol solvent and dispersants. The effect of ethylene glycols, diethylene glycol (DEG), triethylene glycol, and tetraethylene glycol as solvents, as well as polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide as dispersants on the ink properties was investigated. The X-ray diffraction, Fourier-transform infrared (FTIR), electron microscopy (FESEM/TEM) and dynamic light scattering analyses were performed to characterize the features of nanopigments. Crystalline V–ZrSiO4 nanopigment was obtained at 1100°C by DEG solvent in the presence of PVP. The sizes of the resulting nanoparticles were in the range of 10–50 nm. The achieved suspensions were tested as ceramic inks on a tile, and the colorimetric CIELAB parameters were measured. The CIE L*a*b* values confirmed the blue color. The surface tension and viscosity of prepared ceramic ink, as well as microstructure of the annealed nanopigments, were in the range required for drop-on-demand inkjet printers.

An Experimental Method for Generating Shear-Free Turbulence Using Horizontal Oscillating Grids

An experimental apparatus driven by horizontal oscillating grids in a water tank is proposed for generating shear-free turbulence, which is measured using Particle Image Velocimetry (PIV). The performances of the proposed apparatus are investigated through the instantaneous and root-mean-square (RMS) velocity, Reynolds stress, length and time scale, frequency spectra and dissipation rate. Results indicate that the turbulence at the core region of the water tank, probably 8 cm in length, is identified to be shear-free. The main advantage of the turbulence driven by horizontal oscillating mode is that the ratios of the longitudinal turbulent intensities to the vertical values are between 1.5 and 2.0, consistent with those ratios in open-channel flows. Additionally, the range of the length scale can span the typical sizes of suspended particles in natural environments, and the dissipation rate also agrees with those found in natural environments. For convenience of experimental use, a formula is suggested to calculate the RMS flow velocity, which is linearly proportional to the product of oscillating stroke and frequency. The proposed experimental method in this study appears to be more appropriate than the traditional vertical oscillating mode for studying the fundamental mechanisms of vertical migratory behavior of suspended particles and contaminants in turbulent flows.

Hydraulic, wash-off and sediment transport experiments in a full-scale urban drainage physical model

This paper presents a dataset obtained from hydraulic and sediment transport experiments performed in a full-scale urban drainage physical model of 36 m2. The study seeks to accurately measure sediment mobilization through the different parts of the model (surface, gully pots and pipe system), also obtaining a precise characterization of water flow and using realistic rainfall simulator to ensure the transferability of the results. Three different rain intensities and five sediment granulometries were tested in 6 hydraulic and 23 wash-off and sediment transport experiments. The following experimental data were produced: surface elevations and 2D runoff velocities measured by visualization techniques; surface and in-pipe water depths; flow discharges, total suspended solids concentrations and particle size distribution at the entrance of the gully pots and at the pipe system outlet; and sediment mass balances. This data is optimal for developing and validating wash-off and sediment transport formulations in urban drainage models, towards better treatment and management techniques for minimizing the impact of urban surface pollutants on the environments of towns and cities.

Powder hybrid nanomaterial: Detonation nanodiamonds – Carbon nanotubes and its stable reversible water nanofluids

A hybrid nanomaterial composed of detonation nanodiamonds-multi-walled carbon nanotubes (DND-CNT) in powdered form and the form of stable recoverable water nanofluid was obtained. The ability to obtain a hybrid material in the form of powder, as well as in the form of an aqueous suspension opens the way for the creation of new composite materials based on metals and polymers, as well as new types of nanofluids. Particle size in water suspension was investigated by dynamic light scattering (DLS) method and has been shown that while the original DND was agglomerates with the particle size about one μm, the particles size of a hybrid material in water suspension was 40–60 nm. Such result was achieved by growing multi-walled carbon nanotubes on the surface of nanodiamonds aggregates coated with a metal catalyst using catalyst chemical vapor deposition (CCVD) method for nanotubes growth. The resulting nanomaterial is a powdered hybrid material obtained based on a scalable technology. The measured electrical conductivity of the water suspension amounted to 35 μS/cm what is 6 times higher than the electrical conductivity of the pure distilled water.

Determination of the size of suspended organic particles from light scattering phase function and their relationship to the water trophic state

Determination of the size of suspended organic particles from light scattering phase function and their relationship to the water trophic state

ОЧИСТКА КАРЬЕРНЫХ ВОД ПАО «СЕВЕРАЛМАЗ» ОТ ДИСПЕРСНЫХ ЧАСТИЦ ГЛИНИСТОГО МИНЕРАЛА САПОНИТА МЕТОДОМ СГУЩЕНИЯ

In the article, the process of water purification mainly from suspended particles of clay mineral saponite is considered. Those particles are formed during the process of diamond mining in the quarry water of M.V. Lomonosov Mining and Processing Plant owned by PJSC «Severalmaz». The scheme of the existing technology of sedimentation of suspended particles using the acoustic method is shown. Using the granulometry method the size of suspended particles in free volume was studied, and the sedimentation rate of suspended substances was calculated using Stokes' formula. The mineral composition of suspended particles in the quarry water is determined using Х-ray phase analysis. Calculations of the sedimentation rates of suspended particles are given for aluminum sulfate – traditionally used in water clarification – and for calcium-aluminosilicate reagent developed when taking into account the mineral composition. The results of measurements of pH of the clarified water, the content of residual aluminum, and the indicator of turbidity of the water are shown

Fibrillated Cellulose via High Pressure Homogenization: Analysis and Application for Orodispersible Films.

Powdered cellulose (PC) and microcrystalline cellulose (MCC) are common excipients in pharmaceuticals. Recent investigations imply that particle size is the most critical parameter for the different performance in many processes. High-pressure homogenization (HPH) was used to reduce fiber size of both grades. The effect of the homogenization parameters on suspension viscosity, particle size, and mechanical properties of casted films was investigated. PC suspensions showed higher apparent viscosities and yield stresses under the same process conditions than MCC. SLS reduced shear viscosity and thixotropic behavior of both cellulose grades probably due to increased electrostatic repulsion. Homogenization reduced cellulose particle sizes, but re-agglomeration was too strong to analyze the particle size correctly. MCC films showed a tensile strength of up to 16.0MPa and PC films up to 4.1MPa. PC films disintegrated within 30s whereas MCC films did not. Mixtures of MCC and PC led to more stable films than PC alone, but these films did not disintegrate anymore. Diclofenac sodium was incorporated in therapeutic dose with drug load of 47% into orodispersible PC films. The content uniformity of these films fulfilled requirements of Ph.Eur and the films disintegrated in 12s. In summary, PC and MCC showed comparable results after HPH and most differences could be explained by the smaller particle size of MCC suspensions. These results confirm the hypothesis that mainly the fiber size during processing is responsible for the existing differences of MCC and PC in pharmaceutical process, e.g., wet-extrusion/spheronization.

Effects of total suspended solids, particle size, and effluent temperature on the kinetics of peracetic acid decomposition in municipal wastewater.

In this study, the influence of total suspended solids (TSS) and particle size as well as effluent temperature on peracetic acid (PAA) decomposition kinetics in municipal wastewater was investigated. PAA decomposition was best described following second order kinetics in primary effluent (PE) and first order kinetics in secondary effluent (SE) samples. For synthetic samples prepared by varying TSS levels, PAA demand increased on average by about 0.042 mg/L in PE and 0.034 mg/L in SE for every 10 mg/L increase in TSS. Similarly, the PAA decay rate constant in these samples increased at a rate of 0.0014 L/mg.min and 0.00039 min-1, respectively, per 10 mg/L TSS. To examine the effect of particle size, synthetic samples with narrow size fractions (20-45, 45-75, and 75-90 μm) were prepared. It was found that samples with smaller particle size fractions had a greater PAA demand and decay rate constant. Effluent temperature also enhanced the PAA decomposition rate with the calculated activation energies for PE and SE samples being 29,980 J/mol and 34,860 J/mol, respectively.

Rheological assessment of cohesive energy density of highly concentrated stereolithography suspensions

The structures of viscous, highly concentrated suspensions used in stereolithography tend to have varying states of flocculation. This phenomenon is directly related to the interparticle spacing and the interparticle forces. The interparticle spacing impacts the depth of cure behavior of the suspensions. In this study, the interparticle forces were determined using the cohesive energy density model. A relationship between particle size distribution of dry powders and cohesive energy density was established. The results showed that the interparticle interactions, size, and coalescence of particles in stereolithography suspensions can be described by the cohesive energy density measurement. It was established that there was no relationship between the cohesive energy density and depth of cure behavior.

Effects of suspended micro- and nanoscale particles on zooplankton functional diversity of drainage system reservoirs at an open-pit mine

Water from mining drainage is turbid because of suspensions. We tested the hypothesis that the chemical composition as well as shape and size of particles in suspensions of natural origin affect the density and functional diversity of zooplankton. The suspensions were analyzed with atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and optical microscopy. Elements found in the beidellite clays were also identified in the mineral structure of the particles. As the size of the microparticles decreased, the weight proportions of phosphorus, sulfur, and chlorine increased in the suspensions. These conditions facilitated the biomass growth of large and small microphages and raptorials. As the size of the nanoparticles decreased, the shares of silicon, aluminum, iron, and magnesium increased. These conditions inhibited raptorials the most. Ecosystem functionality was the highest with intermediate suspension parameters, which were at the lower range of the microphase and the upper range of the nanophase. The functional traits of zooplankton demonstrate their potential for use as sensitive indicators of disruptions in aquatic ecosystems that are linked with the presence of suspensions, and they facilitate gaining an understanding of the causes and scales of the impact of suspensions.

Effect of suspended particles with different grain sizes on the bioaccumulation of PAHs by zebrafish (Danio rerio).

The physicochemical characteristics are different for suspended particles (SPS) with different sizes in rivers. Here, we studied the effect of SPS (1 g L-1) with three different sizes (63-106 μm, 20-63 μm, and <20 μm) on the bioaccumulation of deuterated polycyclic aromatic hydrocarbons (phenanthrene-d10, anthracene-d10, fluoranthene-d10 and pyrene-d10) in zebrafish using passive dosing devices to maintain the freely dissolved concentrations of PAHs-d10 constant in water. The results showed that all the three grain size SPS could be ingested by zebrafish, and there was no significant difference in the amount of ingested SPS among the three grain sizes. The concentrations (lipid-normalized or not) of PAHs-d10 in zebrafish were promoted in the presence of the three different size SPS, and the PAH-d10 concentrations in zebrafish increased with decreasing particle size. Compared with the systems without SPS, the lipid-normalized concentrations of PAHs-d10 increased by 12%-72%, 34%-130%, and 60%-196%, respectively in zebrafish in systems with 63-106 μm, 20-63 μm, and <20 μm of SPS after exposure for 20 h. The stronger effect of SPS with smaller grain sizes was probably due to their lower organic carbon content, lower ratio of black carbon to organic carbon content, smaller particle size, and higher dissolved organic matter contents, which could promote the desorption of PAHs-d10 from ingested SPS and bioaccessibility of PAHs-d10 to zebrafish. This study suggests that in addition to SPS concentration, the suspended particle size should be considered in ecological risk assessment for hydrophobic organic compounds in aquatic environment.

The Effect of Medium Acidity on the Size of Polystyrene Particles in Suspension

The Effect of Medium Acidity on the Size of Polystyrene Particles in Suspension