Search

This project aims to develop, characterize and assess fast-dissolving tablets of Isradipine utilizing the direct compression technique. The characterization process included evaluating various parameters such as friability, bulk density (BD), tapped density (TD), particle size distribution, disintegration time and post-compression attributes like hardness, average weight and thickness, along with the in-vitro drug release profile. The findings indicated that formulation F1 exhibited the shortest disintegration time, the highest drug content, and achieved 100% cumulative drug release within two hours. Additionally, formulations F2, F3, F4, F5 and F6 met all necessary criteria for effective tablet formulation. The evaluation tests for all preparations were successfully conducted. Variations in the disintegrant ratios across formulations resulted in differing drug release patterns and disintegration rates. Overall, the study demonstrates that Isradipine fast-dissolving tablets can significantly improve bioavailability while reducing both dosage and dosing frequency. [ABSTRACT FROM AUTHOR]

This is an article in the field of mineral materials. The utilization of desulfurized gypsum (FGD) to prepare more widely used hemihydrate gypsum plays a very important role in the resource utilization of industrial by-product gypsum. It can not only avoid the large-scale exploitation of natural gypsum, but also realize the resource utilization of desulfurized gypsum. In the process of converting FGD gypsum into hemihydrate gypsum, appropriate concentration of additive and sodium chloride were used as the reaction solution, and the process was heated and stirred under normal pressure. The effects of sodium chloride concentration, additive concentration, solid-liquid ratio, rotation speed and reaction temperature on the phase conversion time and crystal size of dihydrate to hemihydrate gypsum were studied. The increase of additive and sodium chloride concentration not only sped up the phase conversion process but also had a certain inhibitory effect on the average length and average aspect ratio of hemihydrate gypsum crystals. Higher or lower rotation speed hindered the nucleation and growth of hemihydrate gypsum crystals and affected the collision frequency of Ca2+ and SO42- in the NaCl added solution, thus delaying the formation of hemihydrate gypsum. Decreasing the solid-liquid ratio and increasing the temperature had a certain promoting effect on the phase conversion process. At a lower temperature, due to the insufficient driving force of the phase conversion process, it was difficult to transform FGD gypsum into hemihydrate gypsum. The optimal process conditions for preparing hemihydrate gypsum from FGD gypsum were determined as follows: sodium chloride concentration 10%, additive concentration 10%, solid-liquid ratio 1∶5, rotating speed 300 r/min, reaction temperature 100 ℃. Under the best process conditions, the reaction could be completed in 60 min. The average length of the prepared hemihydrate gypsum crystals was as high as 127 μm, and the average aspect ratio was as high as 19. At the same time, the relationship between the activity of water molecules in the solution, the degree of supersaturation and the reaction temperature was studied, and it was determined that the phase conversion process was determined by the temperature and the degree of supersaturation.

Six different commercial powders, finer than 45 μm, were used for examining the effects of particle characteristics on mean particle size and specific surface area. The measurements were carried out using the most commonly used air permeability- and laser light diffraction (scattering) techniques. As the air permeability method has been used as a benchmark for decades in the powder metallurgy (P/M) industry, the physical phenomena that govern the passage of gas through the powder bed under laminar flow conditions were also presented. The experimental data indicate that both methods give similar results for spherical powders. The advantage of laser light systems over gas permeameters is the ability to provide additional information on particle size distribution. Irregularly shaped powders should be analyzed by both techniques, relying on gas permeametry for surface area measurements and on laser light diffraction for the estimation of mean particle size and size distribution. Application of scanning electron microscopy as a complementary technique was found very helpful in the interpretation of data through visualization of individual particles. [ABSTRACT FROM AUTHOR]

Purpose: Products formulated for intramammary (IMM) infusion are intended for the delivery of therapeutic moieties directly into the udder through the teat canal to maximize drug exposure at the targeted clinical site, the mammary gland, with little to no systemic drug exposure. Currently, to our knowledge, there has been no in-vitro matrix system available to differentiate between IMM formulations. Our goal is to develop A custom tailored in-vitro "Matrix of Chemistry, Manufacturing and Control" (MoCMC) System to be a promising future tool for identifying inequivalent IMM formulations. MoCMC can detect inter and intra batch variabilities, thereby identifying potential generics versus brand product similarities or differences with a single numeric value and a specific & distinctive fingerprint. Methods: The FDA-approved IMM formulation, SPECTRAMASTⓇ LC, was selected as the reference product for the MoCMC. Twelve in-house test formulations containing ceftiofur hydrochloride were formulated and characterized. The MoCMC was developed to include six input parameters and three output parameters. The MoCMC system was used to evaluate and compare SPECTRAMASTⓇ LC with its in-house formulations. Results: Based on the MoCMC generated parameters, the distinctive fingerprints of MoCMC for each IMM formulations, and the statistical analyses of MCI and PPI values, in-house formulations, F-01 and F-02 showed consistency while the rest of in-house formulations (F-03-F-12) were significantly different as compared to SPECTRAMASTⓇ LC. Conclusion: This research showed that the MoCMC approach can be used as a tool for intra batch variabilities, generics versus brand products comparisons, post-approval formulations changes, manufacturing changes, and formulation variabilities. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Integral proteins or enzymes are still challenging to purify into their native state because of their need for an amphipathic environment and cofactors. Alkane hydroxylase (AlkB) is a membrane-bound enzyme that catalyzes the hydroxylation of a range of alkanes that have a broad spectrum of applications. In the current study, a novel approach has been explored for partial purification of alkane hydroxylase (AlkB) in its native state through restructuring the lipid bilayer of Penicillium chrysogenum SNP5 into a liposome to extend the native and protective environment to AlkB enzyme. Three different methods i.e., reverse-phase evaporation method (RPEM), detergent-based method (DBM), and ethanol injection method (EIM) have been used for reconstituting its native membrane into liposome. On characterizing liposomes through fluorescence imaging, AFM, and particle size analysis, the reverse-phase evaporation method gave the best results based on the size distribution (i.e., 100–300 nm), the morphology of liposomes, and maximum AlkB specific activity (i.e., 140.68 U/mg). The maximum reconstitution efficiency of 29.48% was observed in RPEM followed by 17.3% in DBM and 12.3% in EIM. On the characterization of the purified AlkB, the molecular weight was measured of 44.6 KDa and the thermostability of liposomes synthesized with the RPEM method was obtained maximum at 55 °C. This approach may open a new strategy for the purification of integral enzymes/proteins in their native state in the field of protein purification and its applications in diversified industries.

Copyright of Revue Française de Géotechnique is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Particle size and chemical composition are the basic parameters of nanomaterials. The nanoscale size endows nanomaterials with special properties different from bulk materials, such as surface and interface effect, small size effect, quantum size effect, macroscopic quantum tunneling effect and dielectric confinement effect. The type and content of chemical components determine the chemical properties of nanomaterials, such as chemical activity, catalytic selectivity, adsorption selectivity and biological affinity. To a large extent, particle size and chemical composition determine the application of nanomaterials in energy, electronics, environment, sensing, biomedicine and other fields. Therefore, the particle size and composition analysis of nanomaterials are of great significance for the optimization and application of their preparation process. Mass spectrometry is one of the main analytical techniques, which is used to detect the mass, elemental composition and chemical structure of particles or molecules, and it can analyze almost all types and forms of materials, with the characteristics of high analysis accuracy and high detection sensitivity. It has been more widely applied in nano-coating thickness analysis, nanomaterials composition analysis, trace impurity analysis and composition distribution analysis. In some recent research studies, mass spectrometry has also been used to analyze the number concentration, particle size and particle size distribution of nanoparticles, demonstrating its potential for particle size measurements in suspensions over a large size range. In this paper, the advances in studies on mass spectrometry in the analysis of the composition and particle size of nanomaterials were reviewed. The basic principles, advantages and disadvantages, range of application and application cases of inductively coupled plasma mass spectrometry, glow discharge mass spectrometry, secondary ion mass spectrometry and matrix-assisted laser desorption ionization mass spectrometry techniques applicable to the analysis of nanomaterials were introduced, demonstrating the potential of mass spectrometry in the characterization of nanomaterials. Finally, this paper summarized the challenges faced by mass spectrometry analysis technology in environmental interference, size characterization of particles with complex morphology, spatial resolution of components and insitu analysis. The strategies to overcome the above problems by designing special instruments for characterization of nanomaterials and combining with other separation and detection techniques were proposed, trying to provide some reference for the development of mass spectrometry characterization techniques of nanomaterials.

An important index to evaluate the process efficiency of coal preparation is the mineral liberation degree of pulverized coal, which is greatly influenced by the particle size and shape distribution acquired by image segmentation. However, the agglomeration effect of fine powders and the edge effect of granular images caused by scanning electron microscopy greatly affect the precision of particle image segmentation. In this study, we propose a novel image segmentation method derived from mask regional convolutional neural network based on deep learning for recognizing fine coal powders. Firstly, an atrous convolution is introduced into our network to learn the image feature of multi-sized powders, which can reduce the missing segmentation of small-sized agglomerated particles. Then, a new mask loss function combing focal loss and dice coefficient is used to overcome the false segmentation caused by the edge effect. The final comparative experimental results show that our method achieves the best results of 94.43% and 91.44% on AP50 and AP75 respectively among the comparison algorithms. In addition, in order to provide an effective method for particle size analysis of coal particles, we study the particle size distribution of coal powders based on the proposed image segmentation method and obtain a good curve relationship between cumulative mass fraction and particle size.

A recently developed Integral Suspension Pressure (ISP) sedimentation-based particle size analysis technique was tested as an alternative to the hydrometer method. The ISP method determines the particle size distribution using an electronic device, namely the PARIO meter. The PARIO meter provides an alternative to collecting manual readings with the hydrometer, by automatically recording differences in suspension pressure during a settling period of up to 24 h at a depth of 18 cm below the surface of the test suspension. The particle size distribution of the samples is then determined by inverse modeling the recorded pressure data. The objective of this study was to validate the accuracy of the ISP method compared to the hydrometer method using a number of soil mixtures manufactured from materials with known particle size composition. Nine soil mixtures with known reference values were analysed by the hydrometer and ISP methods. Statistical comparison of the results revealed that both measurement methods overestimated clay content and underestimated silt content, the hydrometer method providing more accurate results compared to the ISP method. Thirty-eight mixtures of soil were tested using the ISP method to further validate the accuracy. The results indicated that the accuracy of the ISP method depends on the mass of clay-sized particles and the species composition of the clay minerals in suspension. The ISP method obtained more accurate results for soil mixtures containing expandable clay minerals than to those containing non-expandable clays.

[Objective] It is of great significance for clarifying the influence of different pretreatment methods on the measurement of soil particle composition(PSD), which is the basis of studies on water transport, nutrient transport, soil erosion and sediment transport processes. Soil particle composition(PSD) is the basis of soil physical properties and has important implications for [Methods] Typical purple soil natural woodland profile soil(0-110 cm) was selected, and 9 pretreatment methods were adopted, including physical methods of soaking and shaking, and chemical methods of H2O2 and HCl treatment, and then particle analysis was carried out with a Mastersizer 2000 laser particle size analyzer. [Results](1) The median particle size of each physical pretreatment decreased by 33.79 μm on average compared with the direct measurement without any pretreatment(control). The median particle size under pretreatments of soaking, shaking for 2 h, and shaking for 10 h decreased sequentially, but their release effects on clay were weak. There was no significant difference in clay content between different shaking times(p＞0.05). The median particle size of each chemical treatment could be reduced by 32.72 μm on average compared with control. Among them, the H2O2 treatments had a stronger dispersing effect than the HCl treatments, and the clay contents of H2O2 treatments were the highest among all treatments, which were greater than 4%.(2) Each physical pretreatment method had a uniform dispersion effect among soil layers. Sensitivity to different H2O2 dosage of different layer of soil was middle(30-70 cm)＞lower(70-110 cm)＞upper(0-30 cm). Specifically, sand content in the 20-90 cm soil layer under sufficient H2O2 pretreatment increased by 9.5% and silt content decreased by 9.7% compared with 10 ml H2O2 pretreatment. Sensitivity to different HCl pretreatments of different layer of soil was upper and middle＞lower, specifically the sand content of the upper and middle soil(0-90 cm) increased by 6.2% on average under the treatment of 10 ml HCl plus acid washing compared with the treatment without acid washing. The silt content reduced by an average of 5.4%. There was no significant difference in clay content among soil layers under these treatments.(3) There was a significant linear correlation(r＞0.8) between the content of sand and silt and the content of organic matter in the profile under the treatment of sufficient H2O2, but there was no significant correlation between the content of calcium carbonate and any particles under the treatment of HCl. [Conclusion] There are significant differences in PSD between different pretreatment methods, and the amount of reagent in chemical pretreatments affects the PSD obviously, too. This study can provide a reference for the analysis of purple soil particle composition under different research purposes. [ABSTRACT FROM AUTHOR]

Establishing an alternative resource of rare earth elements (REEs) in coal by-products has been a topic of high interest for the past decade. Despite this, research that characterizes REEs in such materials produced in Australia is lacking. This paper focuses on the concentration and occurrence of REEs in power station coal ashes that represent a suite of major economic coal basins in Australia. The concentration of REEs in coal ash samples was determined by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). Fly ash and bottom ash generated at power stations that utilize coals from the Collie Basin in Western Australia contained elevated REE concentrations. A REE-rich fly ash containing 0.21% total rare earth oxides (REO) was subject to further analysis by Scanning Electron Microscopy with Energy Dispersive X-rays (SEM-EDX) and TESCAN Integrated Mineral Analysis (TIMA). Fine (avg. <5 μm) monazite grains were observed in the fly ash which were typically bound to Al/Si-rich phases. A substantial increase in the aqua regia-extractable fraction of REEs occurred when fly ash samples were milled to an ultrafine particle size. The current investigation has demonstrated that Australian coal ash may represent a promising resource of REEs as the demand for these metals increases. [ABSTRACT FROM AUTHOR]

In this work, a composite flocculant (polyferric titanium sulfate–polydimethyldiallylammonium chloride [PFTS–PDMDAAC]) with a rich spatial network structure was prepared for the treatment of simulated wastewater containing polystyrene (PS) micro–nanoparticles. Characterization results showed that the surface of the PFTS–PDMDAAC was a three‐dimensional network polymer of chain molecules that exhibited good thermal stability and formed an amorphous polymer containing multiply hydroxyl‐bridged titanium and iron. When n(OH−) : n(Fe) = 1:2, n(PO43−) : n(Fe) = 0.35, n(Ti) : n(Fe) = 1:8, n(DMDAAC) : n(Fe) = 5:100, and the polymerization temperature is 60°C, the prepared composite flocculant has the best effect. The effects of dosage, pH, and agitation intensity on the flocculation properties of PFTS–PDMDAAC were also studied. The optimal removal rates of PS‐μm and haze by PFTS–PDMDAAC were 85.60% and 90.10%, respectively, at a stirring intensity of 200 rpm, a pH of 9.0, and a PFTS–PDMDAAC dosage of 20 mg/L. The flocs produced by the PFTS–PDMDAAC flocculation were large and compact in structure, and the flocculation mechanism was mainly based on adsorption bridging. Kaolin played a promoting role in the process of PS‐μm removal by PFTS–PDMDAAC floc and accelerated the formation of large and dense flocs. This study provided a reference for the coagulation method to remove micro–nanopollutants in the actual water treatment process. Practitioner Points: A composite flocculant with rich spatial network structure (PFTS–PDMDAAC) was prepared.PFTS–PDMDAAC can effectively remove micro–nano polystyrene (PS) in wastewater.The floc produced by PFTS–PDMDAAC is large and compact in structure.The flocculation mechanism of PFTS–PDMDAAC is mainly adsorption bridging. [ABSTRACT FROM AUTHOR]

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This research describes a simple and straightforward combustion synthesis for SrY2O4:Dy3+ nanoparticles. The synthesis of SrY2O4:Dy3+ was carried out with the use of urea as a fuel. Characterization techniques including as X-ray diffraction (XRD), transmission electron microscope (TEM), and scanning electron microscopy were used to investigate the effect of the synthesis procedure on the structural behaviour of the phosphor. The existence of orthorhombic structure is indicated by XRD. X-ray widening, Williamson–Hall (W–H) analysis, and a size–strain plot were used to examine the effect of crystallite sizes and lattice strain on the peak broadening of SrY2O4:Dy3+. Uniform deformation model (UDM), uniform stress deformation model (USDM), and uniform deformation energy density model (UDEDM), as well as the size–strain plot method, were used to determine strain, stress, and energy density parameters for all XRD peaks (SSP). W–H analysis, SSP, and TEM results all agreed on the mean particle sizes. To quantify visual properties, a photoluminescence spectroscopic method was implemented. Intense emission at 553 nm, characteristic of emission generated by the energy level transition of the Dy3+ ion, was detected in the emission spectra. [ABSTRACT FROM AUTHOR]

Particle size and chemical composition are the basic parameters of nanomaterials. The nanoscale size endows nanomaterials with special properties different from bulk materials, such as surface and interface effect, small size effect, quantum size effect, macroscopic quantum tunneling effect and dielectric confinement effect. The type and content of chemical components determine the chemical properties of nanomaterials, such as chemical activity, catalytic selectivity, adsorption selectivity and biological affinity. To a large extent, particle size and chemical composition determine the application of nanomaterials in energy, electronics, environment, sensing, biomedicine and other fields. Therefore, the particle size and composition analysis of nanomaterials are of great significance for the optimization and application of their preparation process. Mass spectrometry is one of the main analytical techniques, which is used to detect the mass, elemental composition and chemical structure of particles or molecules, and it can analyze almost all types and forms of materials, with the characteristics of high analysis accuracy and high detection sensitivity. It has been more widely applied in nano-coating thickness analysis, nanomaterials composition analysis, trace impurity analysis and composition distribution analysis. In some recent research studies, mass spectrometry has also been used to analyze the number concentration, particle size and particle size distribution of nanoparticles, demonstrating its potential for particle size measurements in suspensions over a large size range. In this paper, the advances in studies on mass spectrometry in the analysis of the composition and particle size of nanomaterials were reviewed. The basic principles, advantages and disadvantages, range of application and application cases of inductively coupled plasma mass spectrometry, glow discharge mass spectrometry, secondary ion mass spectrometry and matrix-assisted laser desorption ionization mass spectrometry techniques applicable to the analysis of nanomaterials were introduced, demonstrating the potential of mass spectrometry in the characterization of nanomaterials. Finally, this paper summarized the challenges faced by mass spectrometry analysis technology in environmental interference, size characterization of particles with complex morphology, spatial resolution of components and insitu analysis. The strategies to overcome the above problems by designing special instruments for characterization of nanomaterials and combining with other separation and detection techniques were proposed, trying to provide some reference for the development of mass spectrometry characterization techniques of nanomaterials. [ABSTRACT FROM AUTHOR]

Six different commercial powders, finer than 45 μm, were used for examining the effects of particle characteristics on mean particle size and specific surface area. The measurements were carried out using the most commonly used air permeability- and laser light diffraction (scattering) techniques. As the air permeability method has been used as a benchmark for decades in the powder metallurgy (P/M) industry, the physical phenomena that govern the passage of gas through the powder bed under laminar flow conditions were also presented. The experimental data indicate that both methods give similar results for spherical powders. The advantage of laser light systems over gas permeameters is the ability to provide additional information on particle size distribution. Irregularly shaped powders should be analyzed by both techniques, relying on gas permeametry for surface area measurements and on laser light diffraction for the estimation of mean particle size and size distribution. Application of scanning electron microscopy as a complementary technique was found very helpful in the interpretation of data through visualization of individual particles.

Centrifugation is a promising method for direct recycling of lithium-ion battery materials from an aqueous slurry. The present work investigates the continuous fractionation of an aqueous anode slurry into the active material graphite and the conductive carbon black in a decanter centrifuge. To evaluate the separation success, two analytical methods utilizing the different particle sizes and sedimentation velocities of the materials were developed and tested. Both methods can detect graphite separation efficiencies up to 90 % based on centrate samples. The detectability of carbon black in sediment samples is more sensitive for the sedimentation analysis, which can measure carbon black separation efficiencies down to 1 %, in contrast to the particle size analysis, allowing the detection of separation efficiencies down to 10 %. Both methods provide similar results in terms of assessing the separation process in the lab-scale decanter centrifuge. At a centrifugal acceleration of 352 g and a volume flow of 66 l/h, more than 90 % graphite can be separated with a low carbon black deposition between 10 % and 20 %. Thus, a high recovery of graphite and carbon black from an aqueous anode slurry by using a decanter centrifuge is basically possible.

The modern food industry requires new analytical methods for high-demand food supplements, personalized diets, or bioactive foods development. One of the main goals of the food industry is to discover new ways of food fortification. This applies to food products or supplements for human and animal diets. In our research, we focused on the solid particles of AproTHEM (dried porcine hemoglobin), which is approved for animal feeding and as a meat product additive, and AproFER 1000 (heme iron polypeptides), which is still being investigated. The study showed the possible application of advanced techniques for the examination of iron-based food additives. We evaluated selected techniques for particle size and morphology examination such as laser diffraction, optical microscopy, as well as scanning electron microscopy, and briefly discussed their usefulness compared with other techniques. On the basis of our results, we proposed a path of microscopic analysis for the study of material homogeneity. The structure of heme iron was evaluated by X-ray diffraction, FT-IR, and Raman spectroscopy supported with thermal behavior analysis (differential scanning calorimeter). Furthermore, a portable colorimeter was applied for L*a*b* color analysis. Our study proved that for new food product development, particle size analysis as well as typically used advanced materials techniques can be successfully applied.

Cymbopogon citratus (DC) stapf. (Gramineae) is a herb known worldwide as lemongrass. The oil obtained, i.e., lemongrass oil has emerged as one among the most relevant natural oils in the pharmaceutical industry owing to its extensive pharmacological and therapeutic benefits including antioxidant, antimicrobial, antiviral and anticancer properties. However, its usage in novel formulations is constrained because of its instability and volatility. To address these concerns, the present study aims to formulate lemongrass-loaded SLN (LGSLN) using hot water titration technique. In the Smix, Tween 80 was selected as a surfactant component, while ethanol was taken as a co-surfactant. Different ratios of Smix (1:1, 1:2, 1:3, 2:1 and 3:1) were utilized to formulate LG-loaded SLN. The results indicated the fact that the LGSLN formulation (abbreviated as LGSLN1), containing lipid phase 10% w/w (i.e., LG 3.33% and SA 6.67%), Tween 80 (20% w/w), ethanol (20% w/w) and distilled water (50% w/w), revealed suitable nanometric size (142.3 ± 5.96 nm) with a high zeta potential value (− 29.12 ± 1.7 mV) and a high entrapment efficiency (77.02 ± 8.12%). A rapid drug release (71.65 ± 5.33%) was observed for LGSLN1 in a time span of 24 h. Additionally, the highest values for steady-state flux (Jss; 0.6133 ± 0.0361 mg/cm2/h), permeability coefficient (Kp; 0.4573 ± 0.0141 (cm/h) × 102) and enhancement ratio (Er; 13.50) was also conferred by LGSLN1. Based on in vitro study results, the developed SLN appeared as a potential carrier for enhanced topical administration of lemongrass oil. The observed results also indicated the fact that the phyto-cosmeceutical prospective of the nanolipidic carrier for topical administration of lemongrass oil utilizing pharmaceutically acceptable components can be explored further for widespread clinical applicability. [ABSTRACT FROM AUTHOR]

With the progress of beneficiation technology, the proportion of fine-grained tailings in beneficiation production is gradually increasing, which makes the requirements for hydraulic classification equipment for filling higher and higher. In view of the high proportion of fine-grained tailings for filling in Jinfeng Gold Mine, Guizhou, and the serious aging of hydraulic classification equipment, this paper studies the optimization of hydraulic classification equipment selection. The necessity and equipment parameters of replacing hydraulic classification equipment are determined through material balance calculation. The effect of replacing hydraulic classification equipment is evaluated from 5 aspects: tailings particle size, underflow yield rate, aggregate concentration, production test block strength and economic benefit. [ABSTRACT FROM AUTHOR]

Ore is an essential industrial raw material and strategic resource that plays an important role in China’s economic construction. The smart mine aims to build an unmanned, efficient, intelligent, and remote factory to improve quality, reduce cost, save energy, and increase the efficiency of mineral resource extraction. Ore image processing technology can automatically and efficiently complete a series of difficult and repetitive tasks, which constitutes an important part of smart mine construction. However, open-air operation modes, high-dust environments, and ore diversity have brought great challenges to ore image processing. Benefiting from its strong automatic feature extraction ability, deep learning can deeply perceive a complex environment, which enables it to play an important role in the ore image processing field and help traditional mining companies transform into efficient, green, and intelligent enterprises. This paper focuses on two production stages, including ore prospecting and belt transportation. We systematically summarize the main applications of deep learning in ore image processing, including ore classification, particle size analysis, and foreign material recognition, sort out the corresponding algorithms, and analyze their advantages and disadvantages. Specifically, according to the number of ores in an image, ore classification is divided into single-object and multi-object classifications. Single-object classification is mostly addressed by image classification networks, while multi-object classification is mostly accomplished by object detection and semantic segmentation networks. Single-object classification plays an important role in geological prospecting. Particle size refers to the size information of ores in an image. Generally, it can be divided into three modes: particle size statistics, particle size classification, and large block detection. Among these modes, the first and the third are mainly used in actual industrial production. Particle size statistics are determined mostly using semantic segmentation networks and can provide a reference for the control of crushers and conveyor belts. Large block detection is performed mostly by adopting object detection networks and can identify the oversized ore on an ore feeding belt and prevent material blockage accidents in the transfer buffer bin between the ore feeding belt and the ore receiving belt. Foreign material recognition detects harmful objects mixed in the ores on the belt to ensure product quality and prevent the belt from tearing. Object detection technology is often used to complete the task of foreign material recognition.

The widespread use of chlorine pre-oxidation in water purification has been limited in several countries owing to the production of carcinogenic byproducts when combined with naturally occurring organic matter. This study investigates the efficient use of potassium permanganate (KMnO4) pretreatment and coagulation enhancement as particle size and molecular weight distribution controlling parameters. KMnO4 pretreatment significantly reduced the apparent molecular weight of humic acid due to KMnO4 reduction and the continuous generation of manganese dioxide (MnO2) formed in situ under neutral and alkaline conditions. The MnO2 formed in situ had adsorption characteristics that enabled it to form large and stable flocs with the hydrolysis products of aluminum sulfate. However, under acidic conditions, KMnO4 pretreatment exhibited strong oxidation characteristics due to Mn(VII) reduction to Mn(II), and the mean particle floc size was the same as without KMnO4 pretreatment. Overall, KMnO4 pretreatment is a useful alternative strategy for traditional pre-oxidation using chlorine and a good coagulant enhancement agent in neutral and basic media. HIGHLIGHTS pH is crucial in the KMnO4 pretreatment mechanism.; Under acidic conditions, KMnO4 pretreatment results in the same mean particle floc size as alum alone.; The in situ formed MnO2 is incorporated with the alum hydrolysis product, forming larger flocs.; KMnO4 pretreatment under optimal conditions results in a significant reduction in the molecular weight distribution of humic acid.;

Internal erosion (IE) often occurs in poor graded sand, one of the traditional treatments is reducing the permeability by grouting. Today, nano-silica becomes a choice of grouting materials as its low viscosity and good penetration capacity. According to present literature, the effect of decreasing loss mass during IE after the improvement of nano-silica was rarely studied. One of the important reasons is that, mass loss during IE was previously focused and was weighed after filtering the effluent by electronic balance, more accurate weighing method should be studied after adding nano-silica which cannot be precisely weighed by electronic balance. In this paper, a new grading method is conducted to monitoring the particle size distribution in the effluent and illustrate the process of IE. Erosion time and permeability are also recorded and analyzed as comparison. The experimental results show that the grading method can monitor precisely the mass loss and the composition of the effluent, grading range of 1-1000 can be adopted to monitor the coagulation of silica gel particles (1-50 , average diameter 11±5 ) and fine sand particles (50-100 , average diameter 65±7 ), grading range of 1-1000 can be adopted to monitor the smaller coagulation of silica gel particles (concentrated in the range of 1-250 nm). Through grading method, the IE of nano-silica improved sand can be divided into three stages: Removal and release of unbonded nano-silica particles and unbonded fine particles; Movement and discharge of bonded particles; Expansion of pores and instability of the whole sample skeleton.

The China Society of Explosives and Blasting required a larger than 20% annual increase in the national use of digital electronic detonators since 2018. So, this article conducted a large number of on-site tests and then used the Hilbert–Huang Transform method to analyze and compare the vibration signals of digital electronic and nonel detonators during the excavation process of minor cross-sectional rock roadways from the perspective of time, frequency, and energy. Then, through vibration energy analysis, identification of actual delay time, and formula derivation, it was proved that the delay time error of the detonator can control vibration wave random interference and reduce vibration. The analysis results showed that when using a segmented simultaneous blasting network for excavation in small-sectioned rock tunnels, nonel detonators may provide more excellent protection to structures than digital electronic detonators. In the same segment, the timing error of nonel detonators produces a vibration wave with a random superposition damping effect, resulting in an average vibration reduction of 19.4% per segment compared to digital electronic detonators. However, digital electronic detonators are superior to nonel detonators for the fragmentation effect on rock. The research conducted in this paper has the potential to facilitate a more rational and comprehensive promotion of digital electronic detonators in China. [ABSTRACT FROM AUTHOR]

Water saturation of rock plays an important role in chipping efficiency and productivity of mechanical excavators. In this study, small-scale linear rock-cutting experiments were performed with a chisel pick on five sandstones, four gypsums, and three synthetic specimens under dry and water-saturated conditions at cutting depths of 1, 3, and 5 mm in order to investigate the mechanical effect of water on the rock-cutting process. In addition, chipping efficiency and cutting particle size distribution in both dry and saturated rock conditions were investigated using sieving analysis and particle size distribution indices. In addition, a new indicator was introduced for evaluating chipping efficiency. Analysis on cutting test results showed that water saturation causes (1) a reduction of production capacity of chisel pick ranging from 1 to 35%, (2) a reduction of chip size and parameters of particle size distribution, and (3) an increase in the proportion of fines produced from rock cutting. The results showed that the reduction of chisel production capacity is greater in saturated rock samples with higher porosity and water content when compared to the same dry conditions. The results of the sieving analysis revealed that all the size parameters of rock debris are reduced in saturated conditions compared to dry conditions. Highlights: Chipping efficiency was investigated in dry and saturated rock cutting with a simple chisel pick. The production capacity, chip size, and weight percentage of large chips were found to be lower in saturated cutting conditions. The proportion of fines was found to be higher in saturated rocks. The reduction of chisel production capacity was greater in saturated rocks with higher porosity and water content when compared to the same dry conditions. There was a strong correlation between cuttings size descriptors and production capacity in both dry and saturated conditions. [ABSTRACT FROM AUTHOR]

Purpose: The laser diffraction method has become increasingly popular during the last decades to measure the grain size distribution of various environmental particles originating from sediments, soils or river suspended sediments. However, the measurement of multimodal samples containing sands is still an issue. The aim of this study is to discuss the limits of the laser diffraction method in measuring the sand fraction of bimodal samples. Materials and methods: A systematic comparison of four commercially available laser diffraction instruments (Cilas 1190L, Fritsch Analysette 22 Nanotec, Malvern Mastersizer 3000, and Sequoia Lisst 200X) is performed on 12 unimodal and bimodal samples of glass beads and silica-rich natural sands. Results: Measured grain size distributions differ between the four instruments. Most important differences occur in bimodal samples containing a sand fraction, where some instruments have major difficulties to estimate the proportion of the fine towards coarse mode correctly, with errors up to 100%. Conclusion: In accordance with the observation of coarse particles accumulating in low-velocity areas within the sampling tank, the creation of an imperfect suspension within the sampling tank is considered as a main reason for the differences. The choice of the most suitable measurement parameters is crucial to obtain accurate and precise measurements. However, these parameters cannot be compared between the instruments, nor exist precise user guidelines. Therefore, testing several measurement parameters before analyzing novel sample compositions using laser diffraction is recommended. [ABSTRACT FROM AUTHOR]

The article offers a review of U.S. Pharmacopeia (USP) chapters relating to the stability, efficacy and safety of messenger RNA (mRNA)-based lipid nanoparticle (LNP)-based COVID-19 vaccines. Topics discussed include the control of particulate matter in injections, particle size distribution (PSD) in lipid injectable emulsions, and technology for quantifying the critical large-diameter tail (LDT) region in PSD.

The widespread use of chlorine pre-oxidation in water purification has been limited in several countries owing to the production of carcinogenic byproducts when combined with naturally occurring organic matter. This study investigates the efficient use of potassium permanganate (KMnO4) pretreatment and coagulation enhancement as particle size and molecular weight distribution controlling parameters. KMnO4 pretreatment significantly reduced the apparent molecular weight of humic acid due to KMnO4 reduction and the continuous generation of manganese dioxide (MnO2) formed in situ under neutral and alkaline conditions. The MnO2 formed in situ had adsorption characteristics that enabled it to form large and stable flocs with the hydrolysis products of aluminum sulfate. However, under acidic conditions, KMnO4 pretreatment exhibited strong oxidation characteristics due to Mn(VII) reduction to Mn(II), and the mean particle floc size was the same as without KMnO4 pretreatment. Overall, KMnO4 pretreatment is a useful alternative strategy for traditional pre-oxidation using chlorine and a good coagulant enhancement agent in neutral and basic media. [ABSTRACT FROM AUTHOR]

A Study of the process followed by an Emulsion Polyvinyl Chloride droplet in a spray dryer is necessary to understand the morphology of produced dry powder. For the Production of E-PVC, vinyl chloride monomer turns into liquid under pressure and high temperature. This liquid is extracted into the water in the form of emulsion with the help of an emulsifier, and polymerization is performed using water-soluble catalysts. Investigating the operational parameters of the latex drying process can provide helpful information for the design process. In the present study, a pilot plant of Arvand petrochemical spray dryer with a scale of 1:10 is constructed and studied. The purpose of this study is to experimentally analyze the drying of E-PVC in a pilot-scale spray dryer with a particular focus on determining the effects of drying conditions on the powder properties including morphology. For this purpose, the pilot-scale dryer is constructed, and the impact of various parameters such as inlet air temperature, atomization ratio, and latex concentration on outlet temperature and powder moisture content are investigated. A scanning electron microscope is employed to observe the particle morphology parameters mentioned above. The results showed that the outlet temperature decreased dramatically by increasing the atomization ratio and latex concentration. The results showed that more than 90% of the E-PVC particles are solid spheres. About 6% of donut-like particles, about 3% of particles with pore, less than 1% of broken hollow particles. The SEM image of latex used in experiments with a concentration of 40% and a Class D was taken to determine the shape of the latex particles. The picture showed that the particles were spherical before the drying, so the particles' final deformation is due to spray parameters changes during the drying process. From the morphological viewpoint, the number of agglomerates increased at higher inlet temperatures. More than 84% of particles maintained their spherical shape and have a diameter of 15-20 microns. [ABSTRACT FROM AUTHOR]

The process audit is an analysis for the operation of an equipment, to establish its performance and to make proposals for measures to increase production, decrease consumption and improve product quality. The objective of the process audit is to establish the actual state of operation for the cement grinding plant (the degree of loading with grinding bodies, the air speed in the mill, the granulation of the material at the entrance and the exit, the wear of the shields, energy consumption) and is the basis for proposing measures for optimization. The audit from a grinding plant is carried out in the following situations: upon commissioning (to record the initial condition of the equipment) after modernization/modifications of the equipment in the composition of the grinding plant whenever there are deviations from the expected performance as a routine test, at least once a year, to appreciate the real condition of the equipment. The paper presents some determinations made at a cement mill from a Romanian cement factory, the sampling method to carry out analyses and recommendations for improving production. [ABSTRACT FROM AUTHOR]

Objectives. The study aimed to develop new methods for the synthesis of cobalt ferrite (CoFe2O4), which is a precursor for the synthesis of CoFe2O4-based functional materials, as well as to study the physicochemical properties of the obtained phases.Methods. Two methods were used for the synthesis of CoFe2O4: (1) heterophase interaction of hydrated iron oxide with cobalt(II, III) oxide and (2) heterophase interaction of hydrated iron oxide with an aqueous solution of cobalt(II) sulfate (CCo = 0.147 mol/L, solid/liquid = 1:43). In both cases, the precursor was hydrated iron oxide (Fe2O3, 84.4 wt %), which was obtained by the heterophase interaction of iron(III) chloride with a concentrated ammonia solution (6.0–9.5 mol/L). The resulting intermediate products were subjected to thermal treatment at 750 °C (synthesis 1) and at 900 °C (synthesis 2) for 10–30 h in increments of 10 h. The synthesized phases and products of their thermolysis were studied by differential thermal analysis and differential thermogravimetry (DTA–DTG), X-ray diffraction analysis (XRDA), and granulometry.Results. The hydrated iron oxide sample remained amorphous even up to the crystallization temperature of 445 °C, which corresponds to the exothermic effect on the DTA curve. Further heating led to the α-modification of iron(III) oxide of the hexagonal system (a = b = 5.037 ± 0.002 Å; c = 13.74 ± 0.01 Å), which has an average particle size of 1.1 μm. XRDA results showed that a synthesis temperature of 750 °C (synthesis 1) and a heat treatment duration of 30 h were sufficient for the formation of a single-phase cobalt ferrite (a = 8.388 ± 0.002 Å) with an average particle diameter of 1.9 μm. For synthesis 2, a higher temperature of 900 °C was used because sample weight loss (about 12.5%) was observed in the temperature range of 720–810 °C based on the DTA results, which was due to the removal of SO2 and SO3. Moreover, when synthesis temperature and duration were at 900 °C and 30 h, respectively, CoFe2O4 with a = 8.389 ± 0.002 Å was formed. The results of the granulometric analysis showed that particles of different diameters were formed. The smallest particle size (1.5 μm) of cobalt ferrite was obtained by the heterophase interaction of hydrated iron(III) oxide (Fe2O3, 84.4 wt %) with an aqueous solution of cobalt sulfate with CCo = 0.147 mol/L. Conclusions. Depending on the method used for the synthesis of cobalt ferrite, particles of different diameters are formed. The smallest particle size of cobalt ferrite was obtained from the heterophase interaction of hydrated iron(III) oxide with an aqueous solution of cobalt(II) sulfate.

At present, the many domestic, large mined-out areas caused by single filling ability of the slurry flow state, thin layer flow and hardening after filling in multilayer structure generally need to finish filling for many times, because after a filling experience shows that filling body in the last solidification of flow, this leads to a lower one side of the roof, and far distance part of the filling body cannot pick up top. The determination of backfill strength is the key problem of the cemented backfill method, and it is affected by many factors. Therefore, through theoretical calculation, laboratory testing and numerical simulation methods, combined with the field filling process, this paper has verified the flow accumulation and stratification characteristics of stope layered filling slurry. When the slurry concentration is 60–73%, the slope increases exponentially from 2.5° to 8°. It is revealed that the delamination and meshing state are the key factors to determine the overall strength of large-scale stope filling through the testing of particle size distribution in interlayer and flow direction. The reduction effect of the number and Angle of structural weak surface formed by layering and filling on strength is revealed: cement–sand ratio 1:12, concentration 68%, standard curing R28 > 1.81 MPa. The strength reduction coefficient is 61.31% and 92.96% when the number of layers is 1–4. The higher the number of layers, the greater is the reduction coefficient, and when the stratification angle increases by 2, the strength of backfill decreases by 20–30%. The verification of stope filling coring shows that the in situ strength reaches 2.42 MPa, which is 0.61 MPa higher than the standard curing strength, with an increase of 33.7%. When the depth is from 1 m to 5 m, the strength increases from 2.26 MPa to 2.69 MPa, with an increase rate of 18.2%. Finally, through the research and application of the comprehensive technology of mining and filling coordination under the complex goaf group, the residual ore resources of Xianglushan tungsten mine are effectively recovered, the volume of goaf is significantly reduced, and the safety of goaf is improved. [ABSTRACT FROM AUTHOR]

The physicochemical, thermal, and tensile characteristics of Pennisetum glaucum stem powder (PGSP) are described in this article. According to chemical analysis, PGSP contains a larger percentage of cellulose (58.43 wt%) and lower percentages of hemicelluloses (12.86 wt%) and lignin (14.34 wt%). PGSP has a crystallinity index of 56.8%, with a crystallite size of 22.37 nm. A scanning electron microscopy and an atomic force microscopy were used to analyze the external morphology of PGSP. The thermogravimetric analysis of the PGSP exhibited a thermal constancy of 230°C and kinetic activation energy of 88.3 kJ/mol, indicating that it might be used as a filler material in thermoplastic resins with processing temperatures up to 230°C. Mechanical testing of PGSP‐reinforced epoxy composites signified that 9 wt% reinforcement is optimal to achieve improved properties. All the above findings of this investigation proved that PGSP can be used as a suitable primary and a secondary filler in polymer matrixes and it can also be used to make fused deposition modeling filaments for 3D printing. [ABSTRACT FROM AUTHOR]

The solid and gaseous residues of coal dust explosion are the physical evidence for analyzing the detonation site and propagation path and the basis for deploying rescue work. The 20 L spherical explosion system is used to conduct explosion experiments on lignite coal dust with different concentrations and particle sizes. And the particle size change of the solid residue and the flammability of the gaseous residue of the lignite coal dust explosion are analyzed. The results show that the particle size range of lignite coal dust explosion solid residues is larger than that of the original lignite coal dust. When the coal dust concentration is constant, as the particle size decreases, the D10 change rate of lignite coal dust explosion solid residues tends to increase negatively, the D50 change rate fluctuates in the range of 10% to 20%, and the D90 change rate tends to increase positively. When the coal dust particle size is constant, as the coal dust concentration increases, the D10 of the lignite coal dust explosion solid residue first decreases and then increases, while the D50 and D90 continue to increase. The lignite coal dust explosion gaseous residue mainly contains O2, CO, H2,CO2,CH4,C2H6,C2H4,C2H2 and C3H6. As the particle size of coal dust decreases or the concentration increases, the content of O2 and CO2 in the gaseous residue decreases continuously, and the content of hydrocarbon gases such as CO, H2 and CH4 increases continuously. When the coal dust particle size is constant, the flammability index of lignite coal dust explosion gaseous residue within the concentration range of 100-200 g/m3 is less than 1, indicating that the gaseous residue is not combustible. The flammability index of lignite coal dust explosion gaseous residue within the concentration range of 300-600 g/m3 is greater than 1, indicating that the gaseous residue is combustible. When the coal dust concentration is constant, the flammability index of lignite coal dust explosion gaseous residue with the particle size of 180-250 μm is less than 1, indicating that the gaseous residue is not combustible. The flammability index of lignite coal dust explosion gaseous residue with the particle size of 38-180 μm is greater than 1, indicating that the gaseous residue is combustible. The content of H2 and CO in the gaseous residue is the key factor affecting the flammability of lignite coal dust explosion gaseous residue. The flammability is mostly affected by H2, followed by CO.

Landslide dams have been recognised as significant components of multi-hazard cascading systems, linking slopes and rivers. Despite the potential for catastrophic consequences, landslide dam breaching and evolution remain under-researched and poorly understood, often due to the remoteness of large volume, valley-blocking landslides and the general lack of high resolution pre- and post-failure survey data. The Hapuku Rock Avalanche presents a unique opportunity to study landslide dam evolution and breaching timelines due to the accessibility of the site and the availability and resolution of pre- and post-failure remote sensing data. Field observations and mapping, sampling, geophysical surveying, and 27 remote sensing surveys from 2016 to 2022 have provided detailed data on the dam. The Hapuku landslide was the largest rock avalanche triggered by the 2016 Mw 7.8 Kaikōura earthquake sequence, occurring ∼9 km upstream of the main highway and rail corridor on the South Island of New Zealand. It dammed the Hapuku River, which rapidly formed a lake behind the 80 m-high deposit. Four major erosion events and three significant partial breach events, identified through observations and remote sensing data differencing, resulted in water outflow from the lake, significant erosion of the dam and deposition of sediment into the river. The partial breaches correspond with less than 1 in 10-year rainfall events in 2017 and 2018, and the first occurred 141 days after dam formation. Seepage and internal erosion of the dam were observed to be progressing upstream before the partial breaches, in which water overtopped the dam. The third partial breach event, 2 years after dam formation, was the most significant erosional event in the last 6 years. The dam has eroded episodically and more locally since 2018, and the degree of erosion appears to be decreasing with time, despite more intense storms. A small lake remains. The evolution of the Hapuku Rock Avalanche dam emphasises the complexity of dam and breaching evolution, which are often oversimplified.

The China Society of Explosives and Blasting required a larger than 20% annual increase in the national use of digital electronic detonators since 2018. So, this article conducted a large number of on-site tests and then used the Hilbert–Huang Transform method to analyze and compare the vibration signals of digital electronic and nonel detonators during the excavation process of minor cross-sectional rock roadways from the perspective of time, frequency, and energy. Then, through vibration energy analysis, identification of actual delay time, and formula derivation, it was proved that the delay time error of the detonator can control vibration wave random interference and reduce vibration. The analysis results showed that when using a segmented simultaneous blasting network for excavation in small-sectioned rock tunnels, nonel detonators may provide more excellent protection to structures than digital electronic detonators. In the same segment, the timing error of nonel detonators produces a vibration wave with a random superposition damping effect, resulting in an average vibration reduction of 19.4% per segment compared to digital electronic detonators. However, digital electronic detonators are superior to nonel detonators for the fragmentation effect on rock. The research conducted in this paper has the potential to facilitate a more rational and comprehensive promotion of digital electronic detonators in China.

• The powder grain size distribution functions obtained using different measurement techniques were compared. • Measurement methods reported different grain size results and had different accuracies. • The range of grain classes and the nature of the particle size distribution had a major influence on the results. This article concerns comparing the grain size distribution functions of mineral powder samples and analyzes errors obtained by various measurement methods. The research used three standard and currently most frequently used methods: sieve analysis, laser diffraction analysis and vision analysis. The most important research, from the point of view of unification of results, consisted in performing precise analyses of the grain size of mineral powders (fly ash, gneiss, quartz sand and Cu ore) in various grain classes. The measurement techniques used in the research and issues related to measurement analytics were characterized. The distribution functions of the grain size distributions of the tested material samples were obtained by different measurement methods and the measurement errors were compared. Using the coefficient of variation CV calculated for characteristic particle diameters, the accuracy of measurements made using various methods was analyzed. It has been shown that different particle size measurement techniques give significantly different particle size distributions for the same material, with the grain size distribution of the measured samples having a greater impact on the results than the material itself. The lowest values of the coefficients of variation were obtained for wet sieve analysis and the highest for laser diffraction. Reliable data informing about grain size distributions were generated for further model calculations necessary to standardize the results between measurement methods. [ABSTRACT FROM AUTHOR]

To achieve the utilization of fine ilmenite (especially −0.075 mm) produced in the titanium-magnetite processing plant in Panzhihua, a radial turbulent outer-cylinder magnetic separator (RTOCMS), was developed in this study. After optimizing the conditions of rotation speed and water flow, an RTOCMS concentrate with TiO2 grade of 22.84% and TiO2 recovery of 66.93% was obtained through one-stage roughing pre-concentration flowsheet. Magnetic force and competing forces were calculated and analyzed to illustrate the pre-concentration mechanism, and the results revealed that the combination of high water flow and high rotation speed resulted in the most effective for pre-concentration of the fine ilmenite in the RTOCMS process. In addition, particle size analysis of the concentrate product indicated that the RTOCMS was effective for the recovery of medium particle sizes (−0.075 + 0.038 mm), with a continued enhancement for the recovery of fine-grained products (−0.038 mm). Hence, the RTOCMS provides an effective way to pre-concentrate fine ilmenite ore. [ABSTRACT FROM AUTHOR]

The physical, hydrological, and physico-chemical properties of horticultural substrates are influenced by particle shape and size. Sieve analysis has been the predominate method used to characterize the particle size distribution of horticultural substrates. However, the literature shows a diversity of techniques and procedures. The effects of agitation time and sample size on particle size distributions of soilless substrates were evaluated for several measures of sieve analysis, including sieve rate (a calculation of the percentage of material passed for each unit time of agitation), distribution median, SD, mass relative span, skewness, and kurtosis. To obtain the standard sieve rate (0.1%/min), pine bark, peat, perlite, and coir required agitation times of 4 minutes and 47 seconds, 7 minutes and 18 seconds, 10 minutes, and 11 minutes, respectively. However, there was concern that unwanted particle breakdown may occur during the particle size analysis of some materials. Therefore, a sieve rate (0.15%/min) for more friable materials was also determined. As a result, the endpoint of sieving was reached sooner for pine bark, peat, perlite, and coir, at 3 minutes and 10 seconds, 4 minutes and 42 seconds, 5 minutes and 14 seconds, and 6 minutes and 24 seconds, respectively. Increasing agitation time resulted in decreased distribution median, SD, and skewness for all materials. Sample sizes half and twice the volume of the recommended initial volume sieved did not change particle size distributions. For more precise characterization of particle size distributions when characterizing substrate components, agitation times and sample sizes should be specified for each material or collectively for all materials to ensure consistency and allow comparisons between results. [ABSTRACT FROM AUTHOR]