Determination Of Particle Size Distribution Research Articles

Multiple scattering effects for polydisperse scatterers in soft media

We explore the effects of polydispersity in 3D heterogeneous media consisting of scattering species (e.g., droplets, particles) in viscous liquids using a multiple scattering formulation to define effective speed and attenuation spectra. We adopt a published formulation [A. L. Gower, M. J. A. Smith, W. J. Parnell, and I. D. Abrahams, in Proceedings of the Royal Society of America (2018), p. 474] that rigorously extends multiple scattering theory to multi-component systems and show that in the long wavelength region it is consistent with a previous heuristic methodology applied to polydisperse scatterers. We investigate cases of a monomodal size distribution of finite width, and multi-modal size distributions with similar species. Further, systems of mixed scatterer species (i.e., different types of scatterer) with different sizes and distributions are considered. We will discuss the implications for inversion of ultrasonic spectra to determine particle size distributions and for the design of materials with targeted properties by varying composition (concentrations of different scatterer species) and scatterer properties.

Digital microscopic image application (DMIA), an automatic method for particle size distribution analysis in waste activated sludge.

An important physical property in environmental samples is particle size distribution. Several processes exist to measure particle diameter, including change in electrical resistance, blocking of light, the fractionation of field flow and laser diffraction (these being the most commonly used). However, their use requires expensive and complex equipment. Therefore, a digital microscopic imaging application (DMIA) method was developed adapting the algorithms used in the helminth egg automatic detector software coupled with a neural network (NN) and Bayesian algorithms. This allowed the determination of particle size distribution in samples of waste activated sludge (WAS), recirculated sludge (RCS), and pre-treated sludge (PTS). The recirculation and electro-oxidation pre-treatment processes showed an effect in increasing the degree of solubilization, decreasing particle size and breakage factor with ranges between 44.29%, and 31.89%. Together with a final NN calibration process, it was possible to compare results. For example, the 90th percentile of equivalent diameter value obtained by the DMIA with the corresponding result for the laser diffraction method. DMIA values: 228.76 μm (WAS), 111.18 μm (RCS), and 84.45 μm (PTS). DMIA processing has advantages in terms of reducing complexity, cost and time, and offers an alternative to the laser diffraction method.

Nanofragmentation of Expanded Polystyrene Under Simulated Environmental Weathering (Thermooxidative Degradation and Hydrodynamic Turbulence)

Fragmentation of macroplastics into microplastics in the marine environment is probably one of the processes that have generated most drive for developing the microplastics research field. Thus, it is surprising that the level of scientific knowledge on the combinative effect of oxidative degradation and mechanical stressors on fragmentation is relatively limited. Furthermore, it has been hypothesized that plastic fragmentation continues into the nanoplastic size domains, but environmentally realistic studies are lacking. Here the effects of thermooxidative aging and hydrodynamic conditions relevant for the shoreline environment on the fragmentation of expanded polystyrene (EPS) were tested in laboratory simulations. The pre-degraded EPS was cut into pieces and subjected to mechanical, hydrodynamic simulations during four-day stirring experiments. Subsamples were filtered and subsequently analyzed with light microscopy with automated image analysis particle size distribution determinations, polymer identification with Raman spectroscopy, Scanning Electron Microscopy (SEM) with automated image analysis particle size distribution. The nanoplastic size fraction was measured using nanoparticle tracking analysis. In addition, the degree of polymer oxidation was spectroscopically characterized with Fourier transform infrared (FTIR) spectroscopy. The results illustrate that fragmentation of the mesoplastic objects is observed already after 2 days, but that is more distinct after 4 days, with higher abundances for the smaller size fractions, which imply more release of smaller sizes or fragmentation in several steps. For the nanoplastic fraction, day four shows a higher abundance of released or fragmented particles than day two. The conclusions are that nanofragmentation is an important and understudied process and that standardized test protocols for both thermooxidative degradation and mechanical treatments mimicking realistic environmental conditions are needed. Further testing of the most common macro- and mesoplastic materials to assess the rates and fluxes of fragmenting particles to micro- and nanoplastic fractions should be conducted.

Application of Photocatalysis Methods to Enhance Sludge Disintegration

This paper investigated the disintegration of waste sludge with different photocatalytic processes. For this objective, the effects of initial pH, reaction time, TiO2 amount with Fe2+, Fe0 and H2O2 doses on the disintegration degree (DD) were determined. Soluble chemical oxygen demand (SCOD) was used as the main parameter in the study. Process optimizations, kinetic study and Disintegration degree calculation were performed based on the SCOD parameter. In order to observe the effect of UV light, UV-A, UV-B, UV-C lights were used, and the best DD was determined. In addition, SEM analyzes were performed to determine Particle Size Distribution, toxicity and sludge characterization in raw sludge and disintegrated sludge. As a result of optimization studies, optimum pH 3, reaction time 60 min, 6 g/kg TS Fe2+, 4 g/kg TS Fe0, 40 g/kg TS/20 g/kg TS H2O2 and 0.8 g/l TiO2 doses were obtained. The highest DD was obtained in the TiO2/Fe0/H2O2/UVB process with 69.49%, while the lowest DD value was obtained in the TiO2/Fe2+/UVC and TiO2/Fe0/UVC processes with 15.25%. Results suggest that the amount of sludge was reduced between 19.2% and 34.6% by photocatalytic disintegration. As a result, it was concluded that the Photocatalysis process is a feasible and efficient process for disintegration of sludge.

Determination of particle size distribution and electrokinetic potential of phyllosilicate powders by photon correlation spectroscopy

Determination of particle size distribution and electrokinetic potential of phyllosilicate powders by photon correlation spectroscopy

Applicability of laser diffraction method for soil particle size distribution analysis of five soil orders in the water erosion region of China

Soil particle size distribution (PSD) is a critical parameter for soil loss estimation in many water erosion models. The laser diffraction method (LDM) has been increasingly applied for soil PSD determination in recent decades, and its applicability and reliability need systematical examinations. The objective was to evaluate the performance of LDM for PSD determination of five soil orders in the water erosion region of China relative to the traditional sieve-pipette method (SPM). A total of 465 soil samples were collected in the five water erosion subregions of China, which correspond to five soil orders of Mollisols, Alfisols, Entisols, Inceptisols, and Oxisols. All the samples were analyzed with LDM for the four size fractions widely employed in water erosion models (i.e., 100 to 2,000, 53 to 100, 2 to 53, and &lt;2 μm), and the corresponding results were compared to those obtained by SPM. The comparisons show varying results between LDM and SPM for the sand content, or the two sand-sized fractions of 100 to 2,000 and 53 to 100 μm. LDM consistently overestimated the silt content and underestimated the clay fraction, yet the magnitude of either the overestimation or underestimation varied among soil orders. The PSD discrepancies shifted the textural classes of 44.8% to 96.2% of the soil samples and, on average, increased the soil erodibility <i>K</i> factor by 0.010 to 0.034 t MJ^–1 h mm^–1 for different soil orders. The optimal clay/silt and silt/sand boundaries of LDM were derived to match the size fractions measured by SPM. Nevertheless, except for the silt/sand boundary of 58.2 μm for one soil order, each of the other threshold boundaries held a Lin’s concordance correlation coefficient less than 0.8, suggesting moderate or poor agreement between LDM and SPM. Linear regression models were also established to convert the four size fractions between the two methods for all the samples as well as for each soil order. However, not all the conversion models were statistically significant at the level of 0.05. Those that were significant varied among soil orders for each size fraction. These findings hold important practical implications for soil PSD determination and water erosion modeling in China and elsewhere.

Plant morphological and functional characteristics combined with elevation and aspect influence phytogenic mound parameters in a dry-hot valley

Isolated plants growing on steep slopes with erodible bedrock are usually associated with the formation of phytogenic mounds in semiarid and arid ecosystems. Identifying the plant characteristics that affect phytogenic mounds and predicting a plant community’s potential for erosion control are of great interest to workers seeking to improve the management of degraded ecosystems. We studied the phytogenic mounds of three dominant perennial grass species found between 1,400 and 1,700 m above sea level in Jiangjiagou Gully: <i>Heteropogon contortus, Eulaliopsis binata</i>, and <i>Eriophorum comosum</i>. Morphological and functional characteristics were measured for a total of 42 individuals from the three grass species on both sunny and shady slope aspects. Soil samples were collected from the mounds and from bare land 30 cm upslope from each mound to determine particle size distribution. Morphological and functional characteristics, as well as mound parameters, were summarized using principal component analysis (PCA). Pearson’s correlation analysis, linear regression analysis, and redundancy analysis were conducted to identify the relationships between plant characteristics and mound parameters. Then we used analysis of covariance to examine the combined effects of aspect and elevation and plant characteristics on mound parameters. We found that there are no differences in morphological characteristics, functional characteristics, or mound parameters between the three grass species, or soil particle size distribution between mounds and bare land. PCA shows that mound parameters are best correlated (positively) with interception length and total dry weight. Crown length in the direction of the slope and root width are also positively correlated with maximum height and maximum width but to a lesser extent. Plant morphological and functional characteristics can explain greater than 60% of the variance of all mound parameters except maximum length, with the greatest contributions from crown length and interception length. Aspect and elevation, combined with some plant characteristics, also affected mound parameters. Our study indicates that perennial grass species can accumulate sediment deposits during growth in a dry-hot valley. Our results provide useful information for evaluating the function of plants in erosion control and for identifying ways to improve the effectiveness of species in mound formation in dry-hot valley ecosystems.

Antimicrobial Activity of Nanostructured Lipid Carriers Loaded Punica granatum Seed Oil against Staphylococcus epidermidis

Nanostructured lipid carriers (NLCs), due to their impressive benefits, have recently been considered in different areas. Besides, NLC loaded with essential oils is attractive for finding more effective antimicrobial products, especially against common bacteria such as Staphylococcus epidermidis (S. epidermidis). This study aims to prepare and characterize NLCs encapsulated with Punica granatum (P. granatum) seed oil (PGS oil-loaded NLCs) and examine the antimicrobial effect of this combination against S. epidermidis. PGS oil-loaded NLCs were prepared using a hot melt homogenization method. Later, they were characterized by determining particle size distribution (particle size analyzer), morphology (scanning electron microscopy (SEM)), and zeta potential (surface charge of NLCs). Minimum inhibitory concentrations (MIC) of PGS oil-loaded NLCs were assessed and compared with seed oil emulsion of P. granatum against S. epidermidis. PGS oil-loaded NLCs were spherical shaped nanoparticles, with a mean size of 102.10 nm and narrow size distribution (PDI = 0.26). The antibacterial assay showed PGS oil-loaded NLCs to have a higher in vitro antimicrobial activity than seed oil emulsion of P. granatum. To conclude, NLCs may be a favorable carrier to develop new antimicrobial agents. Lay Summary: The lipid nanoparticles such as nanostructured lipid carriers (NLCs) appeared as products first on the cosmetic market. Their advantages help them to be used in different healthcare and cosmetic products. With regard to previous studies, Punica granatum (P. granatum) extract shows antimicrobial and antioxidant properties that could be a valuable natural source against the wide ranges of bacteria. Then, P. granatum seed oil (PGS oil-loaded NLCs) prepared in this study can be used in dental and skin-related materials as a new natural antimicrobial product.

Визначення властивостей несферичних порошків сплаву ВТ20 для моделювання щільності упакування

The study of unfavorable titanium alloy powders of VT20 grades was carried out and the methods of computer analysis were applied to determine the parameters of their optimal packaging. Metallographic studies were performed on a scanning electron microscope EVO-40XVP, and elemental analysis was performed using an energy dispersion spectrometer OXFORD INCA Energy 350. Determination of particle size distribution of powders was performed using image analysis software ImageJ. The surface morphology of non-spherical particles of VT20 alloy powder was studied for three different fractions: 100 ... 160 μm, 160 ... 200 μm and 200 ... 250 μm. It is shown that the powder particles are characterized by a nonspherical shape and a small difference in size. There is a tendency according to which when the particle size of the powder of the investigated alloy decreases, their shape approaches spherical. According to the results of particle size analysis, it was found that the usual sieve analysis does not allow to fully assess the distribution of powder by fractions. It was found that for the fraction 200 ... 250 μm the dominant particles are with an average diameter of 226 μm, for the fraction 160 ... 200 μm - 177 μm and for the fraction 100 ... 160 μm - 114 μm, respectively. Thus, for the fraction of titanium powder of the BT20 brand 200 ... 250 the polydispersity is 6.4%, for the fraction 160 ... 200 - 8.3%, and for the fraction 100 ... 160 - 9.1%. It is established that the fluidity of titanium alloy powders of the BT20 brand is: for the fraction 200 ... 250 μm - 62.35 s, for the fraction 160 ... 200 μm - 65.44 s, and for the fraction 100 ... 160 - 68, 73 s. That is, the highest value of fluidity is characterized by the powder with the largest particle size. Simulation of the pre-defined volume filling was performed using the "Spheres test" program. The average radii of particles of VT20 titanium alloy powder particles and the probability of the sizes of each of fractions of powder which is necessary at filling of the set volume was calculatedthe possibility of their precipitation have been established. Based on the obtained results, the packing density of VT20 titanium alloy powders was calculated depending on their fractional composition. It is confirmed that as the particle size of the powder decreases, their packing density increases. The surface morphology of non-spherical particles of VT20 alloy powder of different fractional composition and their particle size characteristics were studied. It is shown that with decreasing fractional composition of powder fractions, their homogeneity and bulk density increase. It was found that finer fractions are characterized by poorer fluidity. The simulation results determine the optimal fractional composition of the powder to fill the pre-specified volume. It is shown that as the size of the test particles decreases, their packing density increases. Keywords: additive production, titanium, microstructure, particle size distribution, bulk density, fluidity, packing density modelingmodelling.

Characterisation of Mg-Zn-Ca-Y powders manufactured by mechanical milling

Purpose: This paper explains mechanical synthesis which uses powders or material chunks in order to obtain phases and alloys. It is based on an example of magnesium powders with various additives, such as zinc, calcium and yttrium. Design/methodology/approach: The following experimental techniques were used: X-ray diffraction (XRD) method, scanning electron microscopy (SEM), determining particle size distributions with laser measuring, Vickers microhardness. Findings: The particle-size of a powder and microhardness value depend on the milling time. Research limitations/implications: Magnesium gained its largest application area by creating alloys in combination with other elements. Magnesium alloys used in various industry contain various elements e.g. rare-earth elements (REE). Magnesium alloys are generally made by casting processes. Consequently, the search for new methods of obtaining materials such as mechanical alloying (MA) offers new opportunities. The MA allows for the production of materials with completely new physico-chemical properties. Originality/value: Thanks to powder engineering it is possible to manufacture materials with specific chemical composition. These materials are characterized by very high purity, specified porosity, fine-grain structure, complicated designs. These are impossible to obtain with traditional methods. Moreover it is possible to refine the process even further minimalizing the need for finishing or machining, making the material losses very small or negligible. Furthermore material manufactured in such a way can be thermally or chemically processed without any problems.

Simultaneous determination of primary particle size distribution and thermal accommodation coefficient of soot aggregates using low-fluence LII.

For the ill-posed inverse problem of LII-based nanoparticle size measurement, recovered primary particle size distribution (PPSD) is sensitive to the uncertainty of LII model parameters. In the absence of reliable prior knowledge, the thermal accommodation coefficient (TAC) and fractal-dependent shielding factor are often required to be inferred simultaneously with the PPSD. In the simplified LII model for low fluence regime, TAC and fractal-dependent shielding factor are combined to define a new fractal-dependent TAC. The present study theoretically verified the feasibility of inferring PPSD and fractal-dependent TAC from the normalized LII signals. Moreover, the inversion is independent of prior knowledge of most full LII model parameters, which is attributed to low laser fluence, normalized signal, and fractal-dependent TAC.

CHARACTERIZATION OF SIZE AND SHAPE OF AMMONIUM PERCHLORATE PARTICLE FROM CHINA, SOUTH KOREA, AND INDONESIA AND THEIR INFLUENCES ON PROPERTIES OF PROPELLANT

The aim of this study is to obtain characteristics of ammonium perchlorate particle that used in Rocket Technology Center (LAPAN). Characterization begin from the determination of particle size distribution with Particle Size Analyzer. The SEM is used to obtain information about the morphology of AP, furthermore, the results are reprocessed using ImageJ software to analyze the shape of AP particle, and the Surface area was obtained by using BET. Characteristic of AP such as particle size, shape, and surface area are important parameters because those are directly related to propellant combustion energy. Ammonium perchlorate was procured from China, South Korea, and Indonesia with a particle size of 200µm From this study, the particle size of APC200, APH200 and API200 was obtained, which are 265 µm, 236 µm, and 242 µm, with particle shape aggregate value of 0,68, 0,38 and 0,33, roundness of 0,57, 0,79,0,63, and surface area of 1,104 m2/g, 5,561 m2/g, and 2,972 m2/g.

Simple Method to Measure the Aerodynamic Size Distribution of Porous Particles Generated on Lyophilizate for Dry Powder Inhalation.

Recently, statistical techniques such as design of experiments are being applied for efficient optimization of oral formulations. To use these statistical techniques for inhalation formulations, efficient methods for rapid determination of the aerodynamic particle size distribution of many samples are needed. Therefore, we aimed to develop a simple method to measure aerodynamic particle size distribution that closely agrees with the results of inhalation characteristic tests. We added attachments for dispersion to the aerodynamic particle sizer (APS) so that formulations could be dispersed under the same condition as for multi-stage liquid impinger (MSLI) measurement. Then, we examined the correlation between MSLI and APS using lyophilizate for dry powder inhalation formulations that generate porous particles just on inhalation. It is difficult to obtain the accurate aerodynamic particle size distribution of porous particles by APS because the particle density is difficult to estimate accurately. However, there was a significant correlation between MSLI and APS when the particle density settings for APS measurement was calculated by a conversion factor based on the result of MSLI. The APS with dispersion attachments and this conversion factor can measure a number of samples in a short time, thereby enabling more efficient optimization of dry powder inhalers.

Particle Size Distribution of Kalamazoo River Sediments by FieldSed

The FieldSed is an inexpensive portable device for performing an image-based soil particle size analysis. The process, which includes the image analysis, is referred to as SedImaging (short for sediment imaging). The FieldSed was used for an investigation of Kalamazoo River sediments to generate over 100 particle size distributions (PSDs). Core samples taken from the river were tested in a nearby field lab. When necessary, samples were processed prior to testing in the FieldSed to remove particles greater than 2.0 mm and those finer than 0.075 mm. Doing so was necessary to ensure the efficiency of the current SedImaging method. A small number of specimens was selected for quality control testing to determine the reproducibility of SedImaging results. This testing also involved sieve analyses in ascertaining the agreement between SedImaging and sieving results. The control test results presented in this paper demonstrate that the FieldSed is a promising device that can rapidly, accurately, and repeatedly determine particle size distributions in field labs for geotechnical and geoenvironmental applications.

Evaluation of Dantrolene Granules Extemporaneously Reformulated from Capsules in a Pharmacy.

Dantrolene capsule, an effective therapeutic agent for the treatment of spasticity, is administered to children who cannot swallow the capsule after reformulation into a powder. The powdered drug can alter the specified dosage and it is also difficult to dispense the powdered formulation because of its bulky and sticky nature. To resolve these problems, we reformulated dantrolene capsules into granules using a centrifugal planetary mixer in the pharmacy. The granules containing lactose-cornstarch, D-mannitol, or microcrystalline cellulose as a diluent were examined to determine particle size distribution, flowability, drug content uniformity, and disintegration time. The granules with microcrystalline cellulose were superior to the other forms, owing to their smaller size, good drug content uniformity, and rapid disintegration. We further investigated the usability of the granules in the dispensing procedure (dividing and packing) and in the dosing process (retrieval from package) using the powders as controls. The deviation of the divided amount and loss on dosing were reduced relative to the powders. In addition, drug dissolution properties and storage stability for 12 months were the same as those of the powders. Therefore, we concluded that dantrolene granules are excellent alternatives as an extemporaneous preparation in pharmacies.

Analytical method development and comparability study for AmBisome® and generic Amphotericin B liposomal products

Liposomal Amphotericin B, known as AmBisome®, is a life-saving antifungal product that sold $407 million in 2019. AmBisome® has a rather complex physical structure in that Amphotericin B (AmpB) forms a stable ionic complex with the lipid bilayer to maintain AmBisome®’s low toxicity and high stability in systemic circulation. Failed attempts to reproduce AmBisome®’s precise structure has resulted in faster drug release and higher toxicity both in vitro and in vivo. In this study, we established several analytical methodologies to quantify liposomal AmpB components, characterize thermal properties of the liposome, and determine particle size distribution, AmpB aggregation state, and drug release kinetics. We applied these methodologies together with in vitro hemolytic potential and antifungal activity tests to characterize multiple lots of AmBisome® and two generic products approved in India, Phosome® and Amphonex®. We also used Fungizone®, a micellar AmpB formulation, and “leaky” AmpB liposomes as negative controls. Our results showed that Phosome® and Amphonex® were both similar to AmBisome®, while Fungizone® and ‘leaky” liposomes exhibited differences in both thermal properties and AmpB aggregation state, leading to faster drug release and higher toxicity. Due to the increased interest of the pharmaceutical industry in making generic AmBisome® and the lack of standard analytical methods to characterize liposomal AmpB products, the methodologies described here are valuable for the development of generic liposomal AmpB products.

Selected physical and chemical properties of soil under different agricultural land-use types in Ile-Ife, Nigeria

This study examined changes in soil properties under different types of agricultural land-use. This was done with a view to extending knowledge on the nature of soil properties under long-term land-use practices. The study investigated six types of land-use: paddock, continuously cropped, secondary forest, teak, oil palm, and cacao plantations. Soil strength and saturated hydraulic conductivity were determined in-situ at two soil depths (0–15 and 15–30 cm) across the land-use types. Soil samples were collected to determine particle size distribution, bulk density, aggregate stability, pH, organic carbon, cation exchange capacity, total nitrogen, and available phosphorus. The data obtained were subjected to analysis of variance and Duncan's multiple range test was used to separate significant means at p ≤ 0.05. The results showed that land-use types such as forest, cacao and continuously cropped had higher saturated hydraulic conductivity, while soil bulk density was highest under continuously cropped land-use type (1.55 g cm−3). The soil aggregates of forest, teak, and oil palm land-use types were more stable, but soil under oil palm land-use had the highest soil strength (5.65 kg m−2). Soil pH across the land-use types was slightly acidic to strongly acidic, while soil organic carbon was least in continuously cropped land (3.87 g kg−1). The total nitrogen content of soil across the land-use types was high, but the available phosphorus was low. Paddock, cacao, and continuously cropped land-use types had higher cation exchange capacity. The results implied that continuous cultivation led to depletion in soil physical and chemical properties, whereas, afforestation and cultivation of tree crops conserved soil properties better. Therefore, the establishment of tree crop plantations and conservative soil management practices such as manuring, mulching, liming, and conservation tillage were suggested to prevent agricultural lands from degradation in areas with soils under similar conditions.

Assessment of a New Ginsenoside Rh2 Nanoniosomal Formulation for Enhanced Antitumor Efficacy on Prostate Cancer: An in vitro Study.

IntroductionGinsenoside Rh2, purified from the Panax ginseng root, has been demonstrated to possess anticancer properties against various cancerous cells including colorectal, breast, skin, ovarian, prostate, and liver cancerous cells. However, the poor bioavailability, low stability on gastrointestinal systems, and fast plasma elimination limit further clinical applications of Ginsenoside Rh2 for cancer treatments. In this study, a novel formulation of niosomal Ginsenoside Rh2 was prepared using the thin film hydration technique.MethodsThe niosomal formulation contained Span 60 and cholesterol, and cationic lipid DOTAP was evaluated by determining particle size distribution, encapsulation efficiency, the polydispersity index (PDI), and surface morphology. The cytotoxic effects of free Ginsenoside Rh2 and Ginsenoside Rh2-loaded niosomes were determined using the MTT method in the PC3 prostate cancer cell line. For the investigation of the in vitro cellular uptake of Ginsenoside Rh2-loaded niosome, two formulations were prepared: the Ginsenoside Rh2-loaded niosomal formula containing 5% DOTAP and the Ginsenoside Rh2-loaded niosomal formula without DOTAP.ResultsThe mean size, DPI, zeta potential, and encapsulation efficiency of the Ginsenoside Rh2-loaded nanoniosomal formulation containing DOTAP were 93.5±2.1 nm, 0.203±0.01, +4.65±0.65, and 98.32% ±2.4, respectively. The niosomal vesicles were found to be round and have a smooth surface. The release profile of Ginsenoside Rh2 from niosome was biphasic. Furthermore, a two-fold reduction in the Ginsenoside Rh2 concentration was measured when Ginsenoside Rh2 was administered in a nanoniosomal form compared to free Ginsenoside Rh2 solutions in the PC3 prostate cancer cell line. After storage for 90 days, the encapsulation efficiency, vesicle size, PDI, and zeta potential of the optimized formulation did not significantly change compared to the freshly prepared samples. The cellular uptake experiments of the niosomal formulation demonstrated that by adding DOTAP to the niosomal formulation, the cellular uptake was enhanced.DiscussionThe enhanced cellular uptake and cytotoxic activity of the Ginsenoside Rh2 nanoniosomal formulation on the PC3 cell make it an attractive candidate for application as a nano-sized delivery vehicle to transfer Ginsenoside Rh2 to cancer cells.

Internal Volumes of Pharmaceutical Compendial Induction Port, Next-Generation Impactor With and Without Its Pre-separator, and Several Configurations of the Andersen Cascade Impactor With and Without Pre-separator.

Background: Determination of aerosol aerodynamic particle size distributions (APSD) from dry-powder inhalers (DPIs), following quality control procedures in the pharmacopeial compendia, requires that the flow through the measurement apparatus, comprising induction port, optional pre-separator, and cascade impactor, starts from zero on actuation of the inhaler, using a solenoid valve to apply vacuum to the apparatus exit. The target flow rate, governed by the inhaler resistance, is reached some time afterward. Understanding the behavior of the DPI design-specific flow rate-rise time curve can provide information about the kinetics of the initial powder dispersion in the inhaler and subsequent transport through the APSD measurement equipment. Accurate and precise measures of the internal volume of each component of this apparatus are required to enable reliable relationships to be established between this parameter and those defining the flow rate-rise time curve.Methods: An improved method is described that involves progressive withdrawal of an accurately known volume of air from the interior passageways of the apparatus-on-test that are closed to the outside atmosphere. This approach is applicable for determining internal volumes of components having complex internal geometries. Filling some components with water, along with volumetric or gravimetric measurement, has proven valuable for the induction port and for checking other measurements.Results: Values of internal volume are provided for the USP (United States Pharmacopeia)/PhEur (European Pharmacopoeia) induction port, the Next-Generation Impactor (NGI™) with and without its pre-separator, and various Andersen 8-stage cascade impactor configurations with and without their pre-separators.Conclusion: These data are more accurate and precise, and therefore update those reported by Copley et al.

Computational Fluid Dynamics Simulation of Iron Ore Reduction in Industrial‐Scale Fluidized Beds

Detailed simulations of industrial‐scale fluidized beds such as the FINEX process are still unfeasible due to the wide range of spatial scales. Due to the computational limitations it is common to apply coarse grids, which do not resolve all relevant structures. In our previous study (Schneiderbauer, AIChE J. 2017, 63, 3562), we have presented subgrid models, which enable the coarse grid simulation of dense large‐scale gas–solid flows. Herein, these corrections are applied to a parcel‐based the dense discrete phase model (DDPM), allowing to study the hydrodynamics of the FINEX process. Furthermore, the parcel approach is augmented by an unreacted shrinking core model (USCM) to account for the direct reduction of the iron ore particles by the reducing agents of H2 and CO. This DDPM model is tested first for a cold pilot‐scale fluidized bed, and second, the USCM approach is validated for the direct reduction in a lab‐scale fluidized bed. Finally, the model is applied to the FINEX process. The results show fairly good agreement with measurements of the average bed voidage and with experimentally determined particle size distributions. The results further indicate that fines are immediately reduced, whereas the reduction of the largest ore grains takes considerably longer.